Version 2 INSPEC search: cPbL Aug 12 2000 Find AUTHOR INAN, U.S. or AUTHOR INAN, U. S. or AUTHOR INAN, U. 272 citations CAUTION!!!!!!!!! Inan first-authored two papers in May 1996 in GRL. One should be called Inan1May96 and the other Inan15May96!! Also, corrected quotes in "early/fast" title. ---------------------------------------------------------------------------- The following are from the large search, described at the top of this document -------------------------------------------------------------------------- /usr/tmp/citation.tmp.28355 @ARTICLE{SalvatiMar00, author={Salvati, M.A. and Inan, U.S. and Rosenberg, T.J. and Weatherwax, A.T.}, title={ Solar wind control of polar chorus }, journal={Geophysical Research Letters}, volume={27}, number={5}, year={2000}, month={Mar}, pages={649-52}, abstract={ The intensity of chorus as observed at several high latitude ground stations in the Antarctic is highly correlated with the solar wind dynamic pressure exerted on the magnetopause boundary. In two different cases, intense chorus and associated precipitation measured as riometer absorption were abruptly interrupted by several minutes of deep quieting. Satellite measurements of solar wind dynamic pressure showed the intensity of chorus to rapidly respond to magnetospheric compression and relaxation over an extended region as evidenced by the fact the effect was observed at multiple sites }, keywords={ atmospheric radiation magnetosphere solar wind magnetosphere radiowave emission plasma wave polar chorus solar wind control solar wind interaction solar wind magnetosphere interaction intensity high latitude Antarctic dynamic pressure magnetopause boundary intense chorus associated precipitation deep quieting magnetospheric compression relaxation AD 1997 02 23 AD 1997 04 11 }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoFeb00, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Fractal structure of sprites }, journal={Geophysical Research Letters}, volume={27}, number={4}, year={2000}, month={Feb}, pages={497-500}, abstract={ A large scale model of sprites based on a phenomenological probabilistic approach to modeling of streamer corona discharges is developed. The model utilizes the experimentally documented macroscopic properties of positive and negative streamer coronas in air and allows a realistic determination of the propagation of multiple breakdown branches in a self-consistent electric field. The model results reproduce the large scale volumetric shapes of sprites, agree with the experimentally documented thundercloud charge moment changes in sprites producing cloud to ground lightning discharges (CGs), and demonstrate fundamental asymmetries between sprites generated by CGs of positive and negative polarity }, keywords={ fractals ionospheric disturbances lightning thunderstorms fractal structure sprites streamer corona discharges macroscopic properties multiple breakdown branches self-consistent electric field large scale volumetric shapes thundercloud charge moment changes cloud to ground lightning discharges }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SampathJan00, author={Sampath, H.T. and Inan, U.S. and Johnson, M.P.}, title={ Recovery signatures and occurrence properties of lightning-associated subionospheric VLF perturbations }, journal={Journal of Geophysical Research}, volume={105}, number={A1}, year={2000}, month={Jan}, pages={183-91}, abstract={ Subionospheric VLF signatures of lightning-associated ionospheric disturbances observed at multiple sites in the central United States are used to investigate the occurrence properties and recovery signatures of characteristic perturbations exhibiting rapid onset followed by slow recoveries. The two different types of events, so-called early/fast and lightning-induced electron precipitation (LEP) [Inan et al., 1996], are distinguished by the lack of presence of a few hundred millisecond delay between VLF event onsets and causative lightning discharges, respectively. Analysis of recovery signatures of the two types of events indicate subtle but distinct differences in the recovery rates. A majority of early/fast events were found to exhibit a more rapid initial recovery to pre-event levels during the first 20 s of recovery, when compared to LEP events. This experimental evidence indicates that the physical nature of the ionospheric disturbance involved in the two classes of events are different, consistent with a theoretical suggestion [Inan et al., 1996]. The occurrence properties of early/fast events observed by the Holographic Array for Ionospheric Lighting (HAIL) receivers indicate that ionospheric disturbances act primarily as forward scatterers }, keywords={ atmospheric electron precipitation atmospherics ionospheric disturbances lightning recovery signatures occurrence properties lightning-associated subionospheric VLF perturbations lightning-associated ionospheric disturbances central United States lightning-induced electron precipitation delay }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{ErgunJan00, author={Ergun, R.E. and Larson, D.E. and Phan, T. and Taylor, D. and Bale, S. and Carlson, C.W. and Roth, I. and Angelopoulos, V. and Raeder, J. and Bell, T. and Inan, U.S. and Bougeret, J.-L. and Manning, R.}, title={ Feasibility of a multisatellite investigation of the Earth's magnetosphere with radio tomography }, journal={Journal of Geophysical Research}, volume={105}, number={A1}, year={2000}, month={Jan}, pages={361-73}, abstract={ Describes the scientific motivation, basic principles, and feasibility of a relatively new measurement technique, radio tomography, and shows how it can be used to investigate the Earth's magnetosphere. The authors demonstrate that a multisatellite radio tomography experiment can produce two-dimensional images of plasma density in the Earth's magnetosphere at sufficient spatial (1/2 R/sub E/) and temporal (À10 s) resolution to address key problems of magnetospheric physics. The imaging technique incorporates well-established radio science methods and computed tomography. Several coplanar satellites are required in orbits that encompass the imaged area. The authors suggest that the large-scale images are more valuable when combined with in situ observations, supporting an unambiguous interpretation of the in situ data and an investigation of the interdependence of small- and large-scale plasma processes }, keywords={ atmospheric techniques magnetosphere magnetospheric electromagnetic wave propagation tomography Earth magnetosphere measurement technique multisatellite radio tomography experiment magnetospheric physics imaging technique radio science methods coplanar satellites large-scale images in-situ observations plasma processes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellJan00, author={Bell, T.F. and Inan, U.S. and Helliwell, R.A. and Scudder, J.D.}, title={ Simultaneous triggered VLF emissions and energetic electron distributions observed on POLAR with PWI and HYDRA }, journal={Geophysical Research Letters}, volume={27}, number={2}, year={2000}, month={Jan}, pages={165-8}, abstract={ The authors report simultaneous observations of energetic 1-20 keV electrons and VLF emissions triggered within the plasmasphere by pulses from ground based VLF transmitters, using the PWI and HYDRA instruments on the POLAR spacecraft. The 1-20 keV electrons have the correct energy to interact with the input pulses through gyroresonance. Emissions are generated by the pulses only when the particle flux is enhanced well above background and the particle pitch angle distribution is very highly anisotropic, with the average equatorial pitch angle exceeding À75 degrees . Because of these high pitch angles, the particles are trapped typically within 7 degrees of the magnetic equator. Only pulses which propagate within whistler mode ducts are observed to trigger emissions. The observed pitch angle anisotropies are much larger than those assumed in present models of the VLF emission triggering phenomenon, and thus the authors' observations provide a starting point for understanding the emission process }, keywords={ atmospheric radiation magnetosphere magnetosphere radiowave emission VLF triggered emission energetic electron distribution POLAR PWI HYDRA plasmasphere ground based VLF transmitter radiowave excitation gyroresonance particle pitch angle distribution equatorial pitch angle whistler mode duct pitch angle anisoptropy radiowave heating experiment AD 1996 AD 1997 1 to 20 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Barrington-LeighDec99, author={Barrington-Leigh, C.P. and Inan, U.S. and Stanley, M. and Cummer, S.A.}, title={ Sprites triggered by negative lightning discharges }, journal={Geophysical Research Letters}, volume={26}, number={24}, year={1999}, month={Dec}, pages={3605-8}, abstract={ High altitude air breakdown, manifested as "red sprites", is reported in close association with negative cloud-to-ground lightning (-CG) on at least two occasions above an unusual storm on August 29, 1998. Data from high speed photometry, low-light-level video, and receivers of lightning electromagnetic signatures in the frequency range 10 Hz to 20 kHz are used to establish the association and indicate that the causative -CG discharges effected unusually large vertical charge moment changes ( Delta M/sub Qv/) of up to 1550 C.km in 5 ms. The existence of sprites caused by -CG events, rather than the regularly associated +CG events, has immediate implications for sprite models and observations }, keywords={ atmospheric electricity ionospheric disturbances lightning photometry negative lightning discharges sprite triggering high altitude air breakdown red sprites negative cloud-to-ground lightning AD 1998 08 29 high speed photometry low-light-level video lightning EM signatures vertical charge moment changes sprite models sprite observations N Gulf of California Mexico 10 Hz to 20 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JohnsonDec99, author={Johnson, M.P. and Inan, U.S. and Lauben, D.S.}, title={ Subionospheric VLF signatures of oblique (nonducted) whistler-induced precipitation }, journal={Geophysical Research Letters}, volume={26}, number={23}, year={1999}, month={Dec}, pages={3569-72}, abstract={ Subionospheric very low frequency (VLF) signal perturbations observed at multiple sites in association with individual lightning discharges exhibit onset delays which steadily increase with increasing L-value. The timing of the onsets and the inferred spatial extent (À1000 km) of the ionospheric disturbance are consistent with those expected for electron precipitation induced by obliquely propagating (i.e., nonducted) whistlers }, keywords={ atmospheric electron precipitation ionospheric electromagnetic wave propagation magnetospheric electromagnetic wave propagation radiation belts whistlers magnetosphere radiation belt radiowave propagation whistler subionospheric signature VLF signature nonducted whistler-induced precipitation oblique whistler-induced precipitation trapped particle wave particle interaction EM wave onset delay L-value spatial extent timing ionospheric disturbance electron precipitation obliquely propagating whistler }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{DemirkolDec99, author={Demirkol, M.K. and Inan, U.S. and Bell, T.F. and Kanekal, S.G. and Wilkinson, D.C.}, title={ Ionospheric effects of relativistic electron enhancement events }, journal={Geophysical Research Letters}, volume={26}, number={23}, year={1999}, month={Dec}, pages={3557-60}, abstract={ The relativistic electron population as measured both at geosynchronous orbit and at low altitudes at subauroral latitudes exhibits pronounced fluctuations in association with magnetospheric substorm and solar activity. A ground-satellite correlative study based on amplitude and phase measurements of VLF signals propagating in the Earth-ionosphere waveguide indicates that the relativistic electron enhancements are accompanied by similar enhancements in nighttime ionospheric conductivity produced by associated enhanced precipitation. VLF signal amplitudes are found to exhibit >10 dB changes, showing the same 27 day cycle and 2-3 day rise and fall time pattern as relativistic electron enhancement events recorded by GOES 7 and SAMPEX, and indicating that the nighttime lower ionospheric electron density at subauroral latitudes is detectably affected by 27-day periodicity in solar rotation }, keywords={ atmospheric electron precipitation ionosphere ionospheric disturbances ionospheric electromagnetic wave propagation ionosphere magnetosphere interaction ionospheric effect relativistic electron enhancement event subauroral latitude fluctuations substorm solar activity magnetic storm ionospheric disturbance VLF signal Earth-ionosphere waveguide night nighttime electrical conductivity enhanced precipitation elecron precipitation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanNov99, author={Inan, U.S. and Lehtinen, N.G. and Lev-Tov, S.J. and Johnson, M.P. and Bell, T.F. and Hurley, K.}, title={ Ionization of the lower ionosphere by gamma -rays from a magnetar: detection of a low energy (3-10 keV) component }, journal={Geophysical Research Letters}, volume={26}, number={22}, year={1999}, month={Nov}, pages={3357-60}, abstract={ A gigantic periodic flare from the soft gamma repeater SGR 1900+14 produced enhanced ionization at ionospheric altitudes of 30 to 90 km, which was observed as unusually large amplitude and phase changes of very low frequency (VLF) signals propagating in the Earth-ionosphere waveguide. The VLF signals remained perturbed for À5 min and exhibited the 5.16 s periodicity of the giant flare detected on the Ulysses spacecraft (Hurley et al., 1999). Quantitative analysis indicates the presence of an intense initial low energy (3-10 keV) photon component that was not detectable by the Ulysses instrument }, keywords={ atmospheric ionisation gamma-ray effects gamma-ray sources (astronomical) ionospheric disturbances lower ionosphere ionization gamma -rays magnetars low energy component detection gigantic periodic flare soft gamma -ray repeater enhanced ionization ionospheric altitudes VLF signals low energy photon component 30 to 90 km 5.16 s 3 to 10 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{LehtinenNov99, author={Lehtinen, N.G. and Bell, T.F. and Inan, U.S.}, title={ Monte Carlo simulation of runaway MeV electron breakdown with application to red sprites and terrestrial gamma ray flashes }, journal={Journal of Geophysical Research}, volume={104}, number={A11}, year={1999}, month={Nov}, pages={24699-712}, abstract={ A three-dimensional Monte Carlo model of the uniform relativistic runaway electron breakdown in air in the presence of static electric and magnetic fields is used to calculate electron distribution functions, avalanche rates, and the direction and velocity of avalanche propagation. The authors also derive the conditions required for an electron with a given momentum to start an avalanche in the absence of a magnetic field. The results are compared to previously developed kinetic and analytical models and their own analytical estimates, and it is concluded that the rates used in many early models [e.g., Lehtinen et al., 1997; Taranenko and Roussel-Dupre, 1996; Yukhimuk et al., 1998; Roussel-Dupre et al., 1998] are overestimated by a factor of À10. The Monte Carlo simulation results are applied to a fluid model of runaway electron beams in the middle atmosphere accelerated by quasi-electrostatic fields following a positive lightning stroke. In particular, the authors consider the case of lightning discharges which drain positive charge from remote regions of a laterally extensive (>100 km) thundercloud, using a Cartesian two-dimensional model. The resulting optical emission intensities in red sprites associated with the runaway electrons are found to be negligible compared to the emissions from thermal electrons heated in the conventional type of breakdown. The calculated gamma ray flux is of the same order as the terrestrial gamma ray flashes observed by the Burst and Transient Source Experiment detector on the Compton Gamma Ray Observatory }, keywords={ atmospheric electricity atmospheric radiation gamma-rays lightning mesosphere mesosphere middle atmosphere electric discharge electricity electric breakdown model Monte Carlo simulation runaway MeV electron breakdown red sprite gamma ray flash gamma-ray emission lightning three-dimensional model gamma-rays relativistic runaway electron distribution function avalanche rate propagation velocity propagation direction quasi-electrostatic field optical emission }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{LaubenAug99, author={Lauben, D.S. and Inan, U.S. and Bell, T.F.}, title={ Poleward-displaced electron precipitation from lightning-generated oblique whistlers }, journal={Geophysical Research Letters}, volume={26}, number={16}, year={1999}, month={Aug}, pages={2633-6}, abstract={ New simulation results show that obliquely propagating lightning-generated whistlers which fill vast volumes of the magnetosphere readily induce significant energetic electron precipitation over large regions of the ionosphere, depositing appreciable energy flux to the upper atmosphere at locations substantially poleward of the lightning source. These results provide a new interpretation for the observed spatial relationships between lightning discharges and subsequently disturbed ionospheric regions inferred from subionospheric signal perturbations (i.e. Trimpi-events) reported in several lightning-induced electron precipitation (LEP) studies }, keywords={ atmospheric electron precipitation magnetospheric electromagnetic wave propagation whistlers magnetosphere radiowave propagation poleward displaced electron precipitation lightning-generated oblique whistlers whistler simulation obliquely propagating oblique propagation ionosphere poleward displacement lightning wave particle interaction Trimpi-event }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JohnsonAug99, author={Johnson, M.P. and Inan, U.S. and Lev-Tov, S.J. and Bell, T.F.}, title={ Scattering pattern of lightning-induced ionospheric disturbances associated with early/fast VLF events }, journal={Geophysical Research Letters}, volume={26}, number={15}, year={1999}, month={Aug}, pages={2363-6}, abstract={ Simultaneous observations of early/fast very low frequency (VLF) events at nine closely spaced (À65 km) sites are used together with a numerical model of the propagation and scattering of VLF signals in the Earth-ionosphere waveguide to directly measure the scattering pattern of associated ionospheric disturbances. In cases when the causative lightning is within 700 km of the north-south array of observing sites, early/fast VLF events are typically observed at no more than 2 or 3 sites, which indicates a narrow beam of the scattered signal in the forward direction. In the different cases studied, forward scattering patterns exhibit 15 dB beamwidths of less than 30 degrees consistent with horizontal extent of 90+or-30 km }, keywords={ atmospherics Earth-ionosphere waveguide electromagnetic wave scattering ionospheric disturbances lightning scattering pattern lightning-induced ionospheric disturbances early/fast VLF events fast VLF events propagation scattering Earth-ionosphere waveguide ionospheric disturbances }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoMay99, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Mesospheric electric field transients due to tropospheric lightning discharges }, journal={Geophysical Research Letters}, volume={26}, number={9}, year={1999}, month={May}, pages={1247-50}, abstract={ A physical picture and quantitative two-dimensional electromagnetic modeling of mesospheric electric field transients produced by cloud-to-ground (CG) lightning discharges with short duration currents (<0.5 ms) are presented. The range of applicability of existing quasi-electrostatic models of sprites and the physical conditions under which relatively weak CG lightning discharges (thundercloud charge moment changes less than 50 C *10 km) may initiate sprites are discussed in the context of experimental findings }, keywords={ atmospheric electricity lightning mesosphere mesospheric electric field transients tropospheric lightning discharges 2D EM modelling cloud-to-ground lightning discharges short duration currents quasi-electrostatic models sprites thundercloud charge moment changes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{VeronisJun99, author={Veronis, G. and Pasko, V.P. and Inan, U.S.}, title={ Characteristics of mesospheric optical emissions produced by lightning discharges }, journal={Journal of Geophysical Research}, volume={104}, number={A6}, year={1999}, month={Jun}, pages={12645-56}, abstract={ A new 2D cylindrically symmetric EM model of the lightning-ionosphere interaction includes effects of both the lightning radiated EM pulses (EMP) and the quasi-electrostatic (QE) fields, thus allowing effective studies of lightning-ionosphere interactions on time scales ranging from several microseconds to tens of milliseconds. The temporal and spatial evolution of the electric field, lower ionospheric electron density, and optical emissions calculated with the new model are used to investigate theoretically the effects of the lightning return stroke current waveform and of the observational geometry on the optical signals observed with a photometer. For typical lightning discharges of À100 mu s duration the ionospheric response is dominated by the EMP-induced heating leading to the highly transient and laterally expanding optical flashes known as elves. The optical signal characteristics are found to be highly sensitive to both the observational geometry and the current waveform. The onset delay with respect to the lightning discharge, the duration, and the peak magnitude of optical emissions are highly dependent on the elevation and azimuth angles of field of view of individual photometric pixels. The shape of the optical signal clearly reflects the source current waveform. For a waveshape with risetime of À50 mu s or longer a double-pulse shape of the photometric signal is observed. For cloud to ground lightning discharges of À1 ms duration removing substantial amount of charge, heating and ionization changes induced by the QE field lead to the mesospheric luminous glows with lateral extent <100 km, referred to as sprites }, keywords={ atmospheric radiation atmospheric temperature electromagnetic pulse electron density ionospheric disturbances lightning mesosphere mesospheric optical emissions lightning discharges 2D cylindrically symmetric electromagnetic model lightning-ionosphere interaction EM pulses quasi-electrostatic fields time scales temporal evolution spatial evolution lower ionospheric electron density lightning return stroke current waveform observational geometry EMP-induced heating optical flashes elves onset delay duration source current waveform risetime double-pulse shape photometric signal ionization changes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{ReisingApr99, author={Reising, S.C. and Inan, U.S. and Bell, T.F.}, title={ ELF sferic energy as a proxy indicator for sprite occurrence }, journal={Geophysical Research Letters}, volume={26}, number={7}, year={1999}, month={Apr}, pages={987-90}, abstract={ Broadband ELF/VLF measurements of sferics near Ft. Collins, Colorado, demonstrate that ELF sferic energy is a proxy for sprite occurrence which can be used to estimate the number of sprites produced by a thunderstorm. Ultra-long range (À12000 km) measurements at Palmer Station, Antarctica, confirm the application of this proxy to storms where no video observations of sprites are available. Comparison with high-resolution photometer measurements demonstrate the simultaneity of sprite luminosity and an ELF "second pulse" believed to be radiated by electrical currents within the sprite body (Cummer et al., 1998). Measurements of the second ELF pulse are used to identify a quantitative relationship between the current in sprites and total sprite luminosity }, keywords={ atmospherics thunderstorms ELF sferic energy proxy indicator sprite occurrence broadband ELF/VLF measurements Ft. Collins Colorado thunderstorms ultra-long range measurements Palmer Station Antarctica high-resolution photometer measurements comparison electrical currents second ELF pulse total sprite luminosity }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Barrington-LeighMar99, author={Barrington-Leigh, C.P. and Inan, U.S.}, title={ Elves triggered by positive and negative lightning discharges }, journal={Geophysical Research Letters}, volume={26}, number={6}, year={1999}, month={Mar}, pages={683-6}, abstract={ Optical flashes in the lower ionosphere due to the transient heating caused by lightning electromagnetic pulses (EMP) are unambiguously identified with the Fly's Eye photometric array. Data from a thunderstorm over Mexico recorded at Langmuir Laboratory on August 27 1997 demonstrate that relatively common negative cloud-to-ground lightning is a previously unrecognized major cause of elves. The spatial extent of the transient heating is shown optically to be typically at least 200-700 km laterally, indicating the possibility for accumulation of ionization effects produced by successive flashes within large nighttime thunderstorm systems. One especially bright event suggests that temporal fine-structure in the causative very low frequency EMP can manifest itself in the photometric record of elves }, keywords={ ionosphere lightning mesosphere thermosphere elf elves optical emission upper atmosphere thermosphere middle atmosphere mesosphere lightning triggered negative lightning discharge positive lightning lightning electric discharge optical flash lower ionosphere transient heating lightning electromagnetic pulse EMP thunderstorm storm Mexico AD 1997 08 27 negative cloud-to-ground lightning cause spatial extent ionization effec temporal fine-structure }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CummerNov98, author={Cummer, S.A. and Inan, U.S. and Bell, T.F.}, title={ Ionospheric D region remote sensing using VLF radio atmospherics }, journal={Radio Science}, volume={33}, number={6}, year={1998}, month={Nov}, pages={1781-92}, abstract={ Lightning discharges radiate the bulk of their electromagnetic energy in the very low frequency (VLF, 3-30 kHz) and extremely low frequency (ELF, 3-3000 Hz) bands. This energy, contained in impulse-like signals called radio atmospherics or sferics is guided for long distances by multiple reflections from the ground and lower ionosphere. This suggests that observed sferic waveforms radiated from lightning and received at long distances (>1000 km) from the source stroke contain information about the state of the ionosphere along the propagation path. The focus of this work is on the extraction of nighttime D region electron densities (in the altitude range of À70-95 km) from observed VLF sferics. In order to accurately interpret observed sferic characteristics, we develop a model of sferic propagation which is based on an existing frequency domain subionospheric VLF propagation code. The model shows that the spectral characteristics of VLF sferics depend primarily on the propagation path averaged ionospheric D region electron density profile, covering the range of electron densities from À10/sup 0/ to 10/sup 3/ cm/sup -3/. To infer the D region density from observed VLF sferics, we find the electron density profile that produces a modeled sferic spectrum that most closely matches an observed sferic spectrum. In most nighttime cases the quality of the agreement and the uncertainties involved allow the height of an exponentially varying electron density profile to be inferred with a precision of À0.2 km }, keywords={ atmospherics D-region electron density ionospheric electromagnetic wave propagation ionospheric techniques radiowave propagation remote sensing ionospheric D-region remote sensing VLF radio atmospherics lightning discharges electromagnetic energy VLF ELF impulse-like signals radio atmospherics sferics multiple reflections propagation path nighttime D-region electron densities frequency domain subionospheric VLF propagation code spectral characteristics 3 Hz to 30 kHz 70 to 95 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{FosterNov98, author={Foster, J.C. and Cummer, S. and Inan, U.S.}, title={ Midlatitude particle and electric field effects at the onset of the November 1993 geomagnetic storm }, journal={Journal of Geophysical Research}, volume={103}, number={A11}, year={1998}, month={Nov}, pages={26359-66}, abstract={ Millstone Hill incoherent scatter radar elevation scans across midlatitudes captured the ionospheric response to storm-induced electric field and precipitation-induced changes near the equatorward extent of the expanding auroral region during the early phases of the November 3-4, 1993, magnetic storm. Solar wind-induced magnetospheric compression was observed at À2307 UT [Borovsky et al.] and a prompt, short-duration (10 min) increase in the upward plasma velocity to >100 m/s at À2319 UT on November 3, 1993 signaled the onset of the storm-induced enhancement of the east ward electric field over Millstone Hill in the premidnight sector at 54 degrees invariant latitude ( Lambda ). This resulted in an uplifting of the F-region ionosphere above the site by À80 km by 2330 UT. Formation of a narrow ionospheric trough poleward of the Millstone site accompanied the auroral convection enhancement at somewhat later times while plasma sheet precipitation produced the ionization at altitudes between 200 and 300 km at Lambda <60 degrees observed by the radar. Strong precipitation of energetic particles from the outer radiation belt was observed by SAMPEX at 58.5 degrees Lambda , near the equatorward limit of the plasmasheet precipitation observed by DMSP and Millstone Hill. Amplitude perturbations of VLF signals propagating in the Earth-ionosphere waveguide serve to localize the energetic radiation belt precipitation to latitudes between 56 degrees Lambda and 58.5 degrees Lambda and provide accurate timing of storm-induced energetic precipitation, whose onset was at À2332 UT in the premidnight sector. A later enhancement of the eastward electric field at latitudes equatorward of Millstone Hill and the storm-induced trough led to a perturbation of the midlatitude ionosphere to Lambda <40 degrees and is the subject of a companion paper }, keywords={ ionosphere ionospheric disturbances magnetic storms ionosphere magnetosphere interaction ionospheric disturbance middle latitude midlatitude particles electric field onset magnetic storm geomagnetic storm AD 1993 11 03 AD 1993 11 04 ionospheric response storm-induced electric field precipitation-induced change expanding auroral region F-region ionospheric trough convection enhancement plasma sheet precipitation particle precipitation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SmithOct98, author={Smith, A.J. and Engebretson, M.J. and Klatt, E.M. and Inan, U.S. and Arnoldy, R.L. and Fukunishi, H.}, title={ Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations }, journal={Journal of Geophysical Research}, volume={103}, number={A10}, year={1998}, month={Oct}, pages={23611-22}, abstract={ Describes amplitude modulations in the frequency range 0-500 mHz of ELF/VLF (0.5-4.0 kHz) radio wave power recorded throughout 1993 and 1995 at Halley and South Pole stations, Antarctica, which lie in approximately the same magnetic meridian and at geomagnetic latitudes ( Lambda ) of 61 degrees and 74 degrees , respectively. Data from the intermediate automatic geophysical observatories P2 and P3 ( Lambda =70 degrees and 72 degrees , respectively) were also analyzed where available. In agreement with earlier work, spectrograms have revealed the frequent daytime (typically 0700-1700 MLT) occurrence of modulations lying almost entirely within the two period ranges: 10-60 s and 4-6 s. The first range corresponds to quasiperiodic (QP) emissions, while the latter is typical of the two-hop whistler mode echo period in the plasma trough, and the events are termed periodic emissions (PEs). QP occurrence rates higher than some earlier studies (335 station-days out of 667 examined) may be attributable to the sensitive spectral analysis technique. The type I QPs (i.e. those correlated with geomagnetic pulsations observed at South Pole and/or P2/P3) were consistent with an upstream wave driver, controlled by the IMF cone angle. Type II QPs (uncorrelated with magnetic pulsations) were always accompanied by PEs, suggesting a link between the two. The authors propose that type II QPs are driven by field line resonant ULF waves which in turn are generated by field-aligned currents arising from PE induced electron precipitation }, keywords={ magnetospheric electromagnetic wave propagation radiowave propagation periodic ELF emissions periodic VLF emissions quasiperiodic ELF emissions quasiperiodic VLF emissions Antarctic stations amplitude modulations radio wave power AD 1993 to 1995 Halley station South Pole station Antarctica intermediate automatic geophysical observatories P2 P3 spectrograms two-hop whistler mode echo period plasma trough periodic emissions spectral analysis geomagnetic pulsations South Pole IMF cone angle field line resonant ULF waves field-aligned currents electron precipitation 0.5 to 4 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoMay98, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Ionospheric effects due to electrostatic thundercloud fields }, journal={Journal of Atmospheric and Solar-Terrestrial Physics}, volume={60}, number={7-9}, year={1998}, month={May}, pages={863-70}, abstract={ Electrostatic thundercloud fields are shown to heat lower ionospheric electrons significantly under night time conditions. The effect is maximized under conditions of higher altitudes of thundercloud charges, larger magnitudes of these charges, and larger scale heights of ambient conductivity profiles. The lower ionospheric conductivity can be modified as a result of the heating by up to one order of magnitude in regions with a characteristic lateral extent of À150 to 350 km. The vertical extent of the heated region is À10 km, at altitudes of À70-80 km, reaching above 85 km in some cases, depending on the ambient night-time conductivity profile. The electron heating may potentially alter the chemical balance in the D-region, modify the ambient levels of optical emissions and the magnitude of electrostatic thundercloud fields which map to higher ionospheric altitudes }, keywords={ atmospheric composition atmospheric electricity atmospheric temperature D-region ionospheric disturbances thunderstorms electrostatic thundercloud fields ionospheric effects lower ionospheric electrons night time conditions thundercloud charges scale height vertical extent electron heating chemical balance D-region optical emissions magnitude 0 to 100 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoSep98, author={Pasko, V.P. and Inan, U.S. and Bell, T.F. and Reising, S.C.}, title={ Mechanism of ELF radiation from sprites }, journal={Geophysical Research Letters}, volume={25}, number={18}, year={1998}, month={Sep}, pages={3493-6}, abstract={ Charge and current systems associated with sprites constitute a part of the large scale atmospheric electric circuit, providing a context for physical understanding of recently discovered ELF radiation originating from currents flowing within the body of sprites. It is shown that the impulse of the electric current driven in the conducting body of the sprite by lightning generated transient quasi-electrostatic fields produces significant electromagnetic radiation in the ELF range of frequencies, comparable to that radiated by the causative lightning discharge }, keywords={ atmospheric radiation atmospherics lightning mesosphere thermosphere thunderstorms radiowave emission ELF ELF radiation sprite mechanism mesosphere thermosphere ionosphere atmospherics thunderstorm vertical electric current vertical current }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{LaBelleSep98, author={LaBelle, J. and Weatherwax, A.T. and Perring, J. and Walsh, E. and Trimpi, M.L. and Inan, U.S.}, title={ Low-frequency impulsive auroral hiss observations at high geomagnetic latitudes }, journal={Journal of Geophysical Research}, volume={103}, number={A9}, year={1998}, month={Sep}, pages={20459-68}, abstract={ Wave receivers in Antarctic Automatic Geophysical Observatories (AGOs) measure spectral features of low-frequency impulsive auroral hiss emissions which cannot be observed at northern hemisphere sites or near manned Antarctic stations due to man-made interference. From observations at AGO-P1 (À80 degrees invariant latitude) the authors distinguish two spectral types of LF impulsive auroral hiss: normal events, in which the power spectral density is a decreasing function of frequency throughout the LF band, presumably peaking in the VLF band below the frequency range of the LF/MF/HF receiver; and LF cutoff events, for which the power spectral density peaks in the LF band with little or no power at VLF. Out of a large sample of impulsive auroral hiss events observed at AGO-P1, 64% are the normal type, 14% are the LF-cutoff type, and 22% are a mixture of both. A hiss propagation model similar to that of Makita (1979) was used to evaluate approximately whether the observed occurrence statistics of LF cutoff auroral hiss are consistent with previous models of auroral hiss generation and propagation. The results indicate that LF cutoff auroral hiss can be explained by propagation effects and suggest that the observed LF cutoff occurrence statistics are consistent with LF impulsive auroral hiss originating at or ducted to altitudes of 2000-5000 km }, keywords={ atmospherics LF impulsive auroral hiss high geomagnetic latitudes Antarctic Automatic Geophysical Observatories low-frequency impulsive auroral hiss emissions wave receivers AGO-P1 normal event LF cutoff events VLF band power spectral density peaks hiss propagation model auroral hiss generation auroral hiss propagation effects }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{LaubenAug98, author={Lauben, D.S. and Inan, U.S. and Bell, T.F. and Kirchner, D.L. and Hospodarsky, G.B. and Pickett, J.S.}, title={ VLF chorus emissions observed by POLAR during the January 10, 1997, magnetic cloud }, journal={Geophysical Research Letters}, volume={25}, number={15}, year={1998}, month={Aug}, pages={2995-8}, abstract={ VLF chorus emissions occur near the dawn meridian in fast response (<60 s) to magnetospheric perturbations caused by sudden fluctuations in solar wind dynamic pressure and southward turnings of the interplanetary magnetic field (IMF) at the arrival of the January 10, 1997 magnetic cloud. Raytracing analysis indicates the likely chorus source region to be near the magnetic equator with rays launched at oblique wave normal angles, for which likely resonant electron energies are in the range EÀ14-30 keV, consistent with observed particle data }, keywords={ atmospheric radiation atmospherics interplanetary magnetic fields magnetospheric electromagnetic wave propagation plasma waves solar wind VLF chorus emissions POLAR observations AD 1997 01 10 magnetic cloud dawn meridian magnetospheric perturbations sudden fluctuations solar wind dynamic pressure southward turning interplanetary magnetic field raytracing analysis chorus source region magnetic equator oblique wave normal angles resonant electron energies particle data 14 to 30 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{VossJun98, author={Voss, H.D. and Walt, M. and Imhof, W.L. and Mobilia, J. and Inan, U.S.}, title={ Satellite observations of lightning-induced electron precipitation }, journal={Journal of Geophysical Research}, volume={103}, number={A6}, year={1998}, month={Jun}, pages={11725-44}, abstract={ Lightning-induced electron precipitation (LEP) from the Earth's radiation belt has been observed on numerous occasions with detectors on the low-altitude S81-1/SEEP satellite. A sequence of seven LEP events on September 9, 1982, and eight events on October 20, 1982, are correlated on a one-to-one basis with one-hop whistlers at Palmer, Antarctica. The temporal profile within a LEP burst has a remarkable fine structure. It is shown to be associated with bunches of magnetically guided and focused 100-to-200 keV electrons that are repeatedly scattered by the atmosphere and bounce between the northern and southern hemispheres. The delay time between the lightning sferic and the arrival of the first electron bunch increases with increasing L as predicted by the first-order order gyresonance theory. The global distribution of strong LEP events observed with the SEEP payload correlates with lightning activity and shows a preferred distribution at 2130 km for the most perturbed case with larger enhancements in selected narrower spectral regions. The predicted IR enhancements should be observable to an orbiting IR sensor }, keywords={ atmospheric electricity atmospheric radiation atmospheric temperature carbon compounds thunderstorms infrared glow thunderstorms heating lower ionospheric electrons CO/sub 2/ emission excitation rate electron collisions steady-state two-dimensional electrostatic-heating upward coupling vibrational energy transfer line-by-line nonLTE limb-viewing radiance profiles charge distributions ambient ionic conductivities tangent heights 4.3 mum N/sub 2/ CO/sub 2/ }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarJul97, author={Sonwalkar, V.S. and Carpenter, D.L. and Helliwell, R.A. and Walt, M. and Inan, U.S. and Caudle, D.L. and Ikeda, M.}, title={ Properties of the magnetospheric hot plasma distribution deduced from whistler mode wave injection at 2400 Hz: ground-based detection of azimuthal structure in magnetospheric hot plasmas }, journal={Journal of Geophysical Research}, volume={102}, number={A7}, year={1997}, month={Jul}, pages={14363-80}, abstract={ Siple station VLF wave injection experiments aimed at finding the properties of the magnetospheric hot plasma were conducted for a 9-hour period between 1705 and 0210 UT on January 23-24, 1988. A special frequency versus time format, lasting 1 min and transmitted every 5 min, consisted of a sequence of pulses, frequency ramps, and parabolas, all in a 1-kHz range centered on 2400 Hz. The transmitted signals, after propagating along a geomagnetic field-aligned duct were recorded at Lake Mistissini, Canada. At various times during the 9-hour interval the Siple signals showed features characteristic of wave-particle interactions, including wave growth, sidebands, and triggered emissions. On the assumption that gyroresonant interactions were responsible for the observed wave growth and saturation, the timescales over which those phenomena varied provide constraints on the possible energetic electron population within the duct. The authors conclude that ground-based active and passive wave experiments have substantial potential for investigating properties of the hot plasma of the magnetosphere }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation magnetospheric hot plasma distribution whistler mode wave injection ground-based detection azimuthal structure Siple station VLF wave injection experiments AD 1988 01 23 to 24 geomagnetic field-aligned duct Siple signals wave-particle interactions wave growth sidebands triggered emissions gyroresonant interactions energetic electron population ground-based active experiments passive wave experiments 2400 Hz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CarpenterJul97, author={Carpenter, D.L. and Sonwalkar, V.S. and Helliwell, R.A. and Walt, M. and Inan, U.S. and Ikeda, M. and Caudle, D.L.}, title={ Probing properties of the magnetospheric hot plasma distribution by whistler mode wave injection at multiple frequencies: evidence of spatial as well as temporal wave growth }, journal={Journal of Geophysical Research}, volume={102}, number={A7}, year={1997}, month={Jul}, pages={14355-62}, abstract={ Discusses and illustrates the use of wave injection at multiple discrete frequencies to study temporal changes in magnetospheric hot electrons with parallel (gyroresonant) velocities in various nonoverlapping ranges. The data studied were acquired during a special 9-hour period of 1.9-2.9 kHz VLF transmissions from Siple Station, Antarctica, to Lake Mistissini, Canada, on January 23-24, 1988. The amplitudes of the leading edges of constant frequency pulses at 1900, 2150, and 2400 Hz were found to vary independently with time. This is interpreted as evidence of a spatial amplification process that accompanied the well known and more readily identifiable phenomena of exponential temporal growth to a saturation level. Evidence of wave-hot plasma interactions showed a dependence on df/dt of the input signal frequency versus time format; in general, the slow frequency ramps showed the highest amplitudes and the fast ramps and parabolas the lowest, in agreement with past work }, keywords={ magnetospheric electromagnetic wave propagation plasma plasma waves whistlers magnetospheric hot plasma distribution whistler mode wave injection spatial wave growth temporal wave growth wave injection multiple frequencies temporal changes magnetospheric hot electrons gyroresonant velocities VLF transmissions Siple Station AD 1988 01 23 to 24 spatial amplification process wave-hot plasma interactions 1.9 to 2.9 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoJul97, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Sprites as evidence of vertical gravity wave structures above mesoscale thunderstorms }, journal={Geophysical Research Letters}, volume={24}, number={14}, year={1997}, month={Jul}, pages={1735-8}, abstract={ Large area multicell thunderstorms lead to the formation of vertically oriented cylindrical structures of gravity waves at mesospheric altitudes closely resembling those observed in optical emissions associated with transient luminous glows called sprites }, keywords={ atmospheric movements gravity waves lightning mesosphere thunderstorms lightning mesosphere middle atmosphere movement gravity wave vertically oriented cylindrical structure sprite sprites vertical gravity wave structure mesoscale thunderstorm optical emission optical emissions transient luminous glow model penetrative convection mesoscale convective complex }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CummerJul97, author={Cummer, S.A. and Inan, U.S.}, title={ Measurement of charge transfer in sprite-producing lightning using ELF radio atmospherics }, journal={Geophysical Research Letters}, volume={24}, number={14}, year={1997}, month={Jul}, pages={1731-4}, abstract={ Transient high altitude optical emissions referred to as "sprites" are believed to occur as a result of the transfer of large amounts of charge (\100-300 C) from cloud altitudes of 5-10 km to the ground. Using a general subionospheric ELF propagation model, the authors quantitatively interpret magnetic field waveforms of ELF radio atmospherics originating in mid-western U.S. lightning discharges and observed at Stanford (\1800 km range) to determine the temporal variation of the lightning current and thereby measure the charge transfer during the stroke. For 6 sprite-producing lightning current waveforms observed on July 24, 1996, the authors find that 25 to 325 coulombs of charge was transferred during the first 5 ms of the discharges, assuming a 10 km altitude for the initial charge }, keywords={ atmospherics clouds ionospheric electromagnetic wave propagation lightning thunderstorms atmosphere troposphere thunderstorm thundercloud electric current electric charge transfer sprite-producing lightning sprites ELF radio atmospherics transient high altitude optical emission cloud subionospheric ELF propagation model magnetic field waveform United States USA temporal variation lightning current AD 1996 07 24 }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CummerApr97, author={Cummer, S.A. and Bell, T.F. and Inan, U.S. and Chenette, D.L.}, title={ VLF remote sensing of high-energy auroral particle precipitation }, journal={Journal of Geophysical Research}, volume={102}, number={A4}, year={1997}, month={Apr}, pages={7477-84}, abstract={ Ground-based measurements of VLF transmitter signals propagating in the Earth-ionosphere waveguide can be used to determine the location of nighttime high-energy (>or approximately=100 keV) auroral particle precipitation. When the region of auroral particle precipitation passes over a VLF propagation path, disturbances in the D-region of the ionosphere created by the high-energy particles perturb the amplitude of VLF signals propagating below in a characteristic manner. Continuous nighttime observations of the amplitude of the signal from the NLK transmitter (24.8 kHz, Jim Creek, Washington) were made in Gander, Newfoundland, during November 1993 and January 1994. Simultaneous images of atmospheric X-rays created by auroral particle precipitation taken by the AXIS instrument on the UARS satellite were examined for times when large-scale auroral particle precipitation extended over the NLK-Gander propagation path. Quantitative characteristics of the precipitation-associated NLK signal perturbations are established from days which clearly exhibit good correlation between the AXIS images and VLF data, and a larger data set from the months of November 1993 and January 1994 is examined statistically to determine the effectiveness of the VLF technique in capturing particle precipitation events. The number of particle precipitation onsets seen in the AXIS images that can be readily identified in the VLF amplitude data is found to be almost 94%. VLF propagation model calculations show that the observed VLF amplitude decreases are consistent with propagation under conditions of enhanced lower ionosphere electron density caused by auroral electron precipitation and suggest that electrons with energies greater than 100 keV are responsible for the VLF amplitude perturbations }, keywords={ atmospheric electron precipitation atmospheric ion precipitation ionospheric techniques ionosphere measurement technique radiowave propagation VLF remote sensing high-energy auroral particle precipitation electron precipitation VLF transmitter signal Earth-ionosphere waveguide location nighttime high-energy precipitation D-region NLK transmitter USA Washington Newfoundland Canada Gander AD 1993 AD 1994 signal perturbation VLF technique ion precipitation 24.8 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoMar97, author={Pasko, V.P. and Inan, U.S. and Bell, T.F. and Taranenko, Y.N.}, title={ Sprites produced by quasi-electrostatic heating and ionization in the lower ionosphere }, journal={Journal of Geophysical Research}, volume={102}, number={A3}, year={1997}, month={Mar}, pages={4529-61}, abstract={ Quasi-electrostatic (QE) fields that temporarily exist at high altitudes following the sudden removal (e.g., by a lightning discharge) of thundercloud charge at low altitudes lead to ambient electron heating (up to \5 eV average energy), ionization of neutrals, and excitation of optical emissions in the mesosphere/lower ionosphere. Model calculations predict the possibility of significant (several orders of magnitude) modification of the lower ionospheric conductivity in the form of depletions of electron density due to dissociative attachment to O/sub 2/ molecules and/or in the form of enhancements of electron density due to breakdown ionization. Results indicate that the optical emission intensities of the 1st positive band of N/sub 2/ corresponding to fast (\1 ms) removal of 100-300 degrees C of thundercloud charge from 10 km altitude are in good agreement with observations of the upper part ("head" and "hair" [Sentman et al., 1995]) of the sprites. The typical region of brightest optical emission has horizontal and vertical dimensions \10 km, centered at altitudes 70 km and is interpreted as the head of the sprite. The model also shows the formation of low intensity glow ("hair") above this region due to the excitation of optical emissions at altitudes \85 km during \500 mu s at the initial stage of the lightning discharge. Comparison of the optical emission intensities of the 1st and 2nd positive bands of N/sub 2/, Meinel and 1st negative bands of N/sub 2//sup +/ and 1st negative band of O/sub 2//sup +/ demonstrates that the 1st positive band of N/sub 2/ is the dominating optical emission in the altitude range around \70 km, which accounts for the observed red color of sprites, in excellent agreement with recent spectroscopic observations of sprites. Results indicate that the optical emission levels are predominantly defined by the lightning discharge duration and the conductivity properties of the atmosphere/lower ionosphere (i.e., relaxation time of electric }, keywords={ airglow atmospheric ionisation ionosphere ionospheric disturbances lightning mesosphere stratosphere thunderstorms thunderstorm lightning mesosphere ionosphere optical emission airglow middle atmosphere quasi-electrostatic heating sprite ionization electron heating model calculation breakdown ionization ionospheric disturbance thundercloud charge head hair red color }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanMar97, author={Inan, U.S. and Barrington-Leigh, C. and Hansen, S. and Glukhov, V.S. and Bell, T.F. and Rairden, R.}, title={ Rapid lateral expansion of optical luminosity in lightning-induced ionospheric flashes referred to as elves' }, journal={Geophysical Research Letters}, volume={24}, number={5}, year={1997}, month={Mar}, pages={583-6}, abstract={ Data acquired by a new array of horizontally spaced photometers boresighted with a low-light-level camera provide the first measurement of the rapid lateral expansion of optical luminosity in lightning-induced ionospheric flashes referred to as elves', occurring over time scales substantially less than 1 ms. The narrow individual fields-of-view of (2.2 degrees *1.1 degrees ) provide a spatial resolution of \20-km at a range of 500 km, enabling the documentation of expansion occurring over a horizontal range of 200 km with a time resolution of \30 mu s. The observed dynamic features of elves are consistent with a model in which the optical output is produced as a result of heating by the electromagnetic pulse (EMP) from a lightning discharge }, keywords={ atmospheric radiation atmospheric temperature ionospheric disturbances lightning plasma radiofrequency heating rapid lateral expansion optical luminosity lightning-induced ionospheric flashes elves dynamic features heating electromagnetic pulse lightning discharge }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CarpenterJan97, author={Carpenter, D.L. and Galand, M. and Bell, T.F. and Sonwalkar, V.S. and Inan, U.S. and LaBelle, J. and Smith, A.J. and Clark, T.D.G. and Rosenberg, T.J.}, title={ Quasiperiodic \5-60 s fluctuations of VLF signals propagating in the Earth-ionosphere waveguide: a result of pulsating auroral particle precipitation? }, journal={Journal of Geophysical Research}, volume={102}, number={A1}, year={1997}, month={Jan}, pages={347-61}, abstract={ Subionospheric very low frequency and low-frequency (VLF/LF) transmitter signals received at middle-latitude ground stations at nighttime were found to exhibit pulsating behavior with periods that were typically in the \5-60 s range but sometimes reached \100 s. The amplitude versus time shape of the pulsations was often triangular or zigzag-like, hence the term "zigzag effect." Variations in the envelope shape were usually in the direction of faster development than recovery. Episodes of zigzag activity at Siple, Antarctica (L\4.3), and Saskatoon, Canada (L\4.2), were found to occur widely during the predawn hours and were not observed during geomagnetically quiet periods. The fluctuations appeared to be caused by ionospheric perturbations at the \85 km nighttime VLF reflection height in regions poleward of the plasmapause. The authors infer that in the case of the Saskatoon and Siple data, the perturbations were centered within \500 km of the stations and within \100-200 km of the affected signal paths. Their horizontal extent is inferred to have been in the range \50-200 km. The assembled evidence, supported by Corcuff's (1996) research at Kerguelen (L\3.7), suggests that the underlying cause of the effect was pulsating auroral precipitation }, keywords={ atmospheric elementary particle precipitation Earth-ionosphere waveguide radiowave propagation quasiperiodic fluctuations VLF signals Earth-ionosphere waveguide pulsating auroral particle precipitation subionospheric LF transmitter signals zigzag effect envelope shape Siple Antarctica Saskatoon Canada ionospheric perturbations nighttime VLF reflection height 5 to 60 s }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Grossman96, author={Grossman, D.A. and Sweeney, K.J. and Frieder, O.}, title={ Client/server performance testing: a case study of a personnel application }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={925-34 vol.2}, abstract={ We present a simulation-based approach to client/server performance testing. This approach uses the Promark Rhobot/Win testing tool to simulate execution of and measure performance of a client/server application. We describe a case study of a large personnel application and address a variety of complexities unique to the client/server environment }, keywords={ business data processing client-server systems distributed databases personnel program testing software performance evaluation virtual machines client server performance testing case study personnel application simulation-based approach Promark Rhobot Win testing tool performance evaluation distributed database }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kostin96, author={Kostin, A.E.}, title={ A protocol for distributed scheduling in a processor network }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={915-24 vol.2}, abstract={ A distributed scheduler is proposed which is based on a special communication protocol in a processor network. An informal description of the protocol used by the scheduler is provided. The protocol was implemented as a model in terms of the extended Petri nets (E-nets). The results of a simulation study are compared to the behaviour of an ideal, centralized scheduler }, keywords={ multiprocessor interconnection networks Petri nets processor scheduling protocols virtual machines distributed scheduling protocol processor network communication protocol extended Petri nets simulation study centralized scheduler job scheduling modeling }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Al-Khayatt96, author={Al-Khayatt, S. and Cooling, J.E.}, title={ Issues in the design of a kernel for distributed, embedded systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={901-13 vol.2}, abstract={ In a number of parallel computations, tasks may be naturally distributed in a functional partitioning manner. Functionally distributed systems are often modelled and controlled as a set of communicating, distributed sub-tasks (processes). The software for such systems invariably reflects the distributed nature of the application. Moreover, the software design and support of such a functional distribution of sub-tasks depends on the degree of interaction of these processes among the different nodes. The design approach advocated in the paper is particularly appropriate to real-time applications. Moreover, it should result in the generation of high quality software which has good run-time performance. This paper is organised to address two issues: task management in a distributed environment; and kernel design to support functional partitioning and the use of distributed variables }, keywords={ message passing network operating systems operating system kernels real-time systems software performance evaluation software quality systems analysis distributed embedded systems kernel design parallel computations distributed tasks functional partitioning functionally distributed systems communicating processes software design real-time applications high quality software run-time performance task management distributed variables message passing }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Chi-Ming-Chung96, author={Chi-Ming Chung and Shih, T.K. and Ying-Hong Wang and Ying-Feng Kou and Yuh-Long Shyy}, title={ Concurrent programming testing and metrics based on task decomposition }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={891-900 vol.2}, abstract={ Software testing and metrics are two important approaches to assure the reliability and quality of software. Testing and metrics of sequential programs have been a fairly sophisticated process, with various methodologies and tools available for use in building and demonstrating the correctness of a program being tested. The emergence of concurrent programming in the recent years, however, introduces new testing problems and difficulties that cannot be solved by testing techniques of traditional sequential programs. One of the difficult tasks is that concurrent programs can have many instances of execution for the same set of input data. Many concurrent program testing methodologies are proposed to solve controlled execution and determinism. There are few discussions of concurrent software testing from the inter-task viewpoints. Yet, the common characteristics of concurrent programming are explicit identification of the large grain parallel computation units (tasks), and the explicit inter-task communication via a rendezvous-style mechanism. We focus the testing view on concurrent programming through task decomposition. We propose four testing criteria to test a concurrent program. The programmer can choose an appropriate testing strategy depending on the properties of concurrent programs. Associated with the strategies, four equations are provided to measure the complexity of concurrent programs }, keywords={ parallel programming program testing program verification software metrics software quality software reliability concurrent programming testing software metrics task decomposition software reliability software quality sequential programs methodologies software tools program correctness controlled execution determinism large grain parallel computation explicit inter-task communication rendezvous-style mechanism program complexity }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Adda96, author={Adda, M. and Dwyer, J. and Bouridane, A.}, title={ The architecture of a RISC multithread processor }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={877-89 vol.2}, abstract={ The major concerns for constructing efficient general purpose massively parallel computers are the programmability and the hardware latency. The latency, which emanates during local or remote memory accesses or during concurrent synchronization of operations, tends to leave the processor idle for several clock cycles and hence deteriorates the performance of the whole system. We present the architecture of a simple RISC multithread processor (RISC-MP). When interleaving the execution of several operations belonging to separate threads, the processor tolerates the local memory, network and synchronization latencies imposed by the components of the system. The processor switches between threads every clock cycle, and allows them to communicate through register banks without necessarily sharing any memory }, keywords={ general purpose computers multiprogramming parallel architectures parallel machines parallel programming performance evaluation reduced instruction set computing synchronisation RISC multithread processor architecture general purpose massively parallel computers programmability hardware latency remote memory access concurrent synchronization clock cycles performance RISC-MP local memory synchronization latencies register banks }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cinar96, author={Cinar, A. and Arslan, A.}, title={ Two approaches on blending }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={869-76 vol.2}, abstract={ Blending is the joining of sharp edges or corners in the intersecting or nonintersecting region of 2D or 3D objects with smooth surfaces or curves, or the smoothing of sharp edges or corners of objects. Two different methods and the relation between these methods are given and blend shapes are realized with the help of the first method. The first method is the creation of surfaces with approximation curves based on three points and the second method is the solution of a parabolic partial differential equation (PPDE) taking the intersection curves as boundary conditions. While the first method is well suited for interactive operations, the second method, which is based on a more detailed mathematical work, needs much more computational power }, keywords={ finite difference methods parabolic equations partial differential equations solid modelling blending sharp edge joining sharp corner joining intersecting region nonintersecting region 2D objects 3D objects smooth surfaces curves sharp edge smoothing sharp corner smoothing blend shapes approximation curves surface creation parabolic partial differential equation intersection curves boundary conditions interactive operations solid modelling }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Stemposz96, author={Stemposz, E.J. and Rutkowski, A.}, title={ Determining faces of a 3D object in engineering drawings based on planar graphs }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={861-8 vol.2}, abstract={ The authors present a method of determining the set of 3D object faces from its projections. The main tool is the algorithm enumerating all inner cycles in a planar undirected simple graph. Since the most time consuming operation they use is sorting of n-element set the computational complexity of the method is O(nlgn) }, keywords={ computational complexity edge detection engineering graphics graph theory image reconstruction object recognition sorting stereo image processing 3D object face determination projections algorithm inner cycle enumeration planar undirected simple graph engineering drawings n-element set sorting computational complexity }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Sarukhanyan96, author={Sarukhanyan, A.G. and Grigoryan, A.M.}, title={ Decomposition of the Hadamard matrices by orthogonal vectors. The paired algorithm for computing of 1-D Hadamard transform }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={851-60 vol.2}, abstract={ The first part of the paper is devoted to the classical algorithm of the Walsh-Hadamard fast transform using only nlog/sub 2/n addition operations where n is a power of two. A problem of decomposition of Hadamard matrices of arbitrary older n,n identical to O(mod4) by orthogonal (-1, +1)-vectors of length k is investigated. An algorithm of the Hadamard fast transform which uses only nlog/sub 2/k+n(n/k-1) addition operations, and in some cases is more efficient than the classical algorithm, is proposed. In the second part, the fast algorithm of computation of the one-dimensional unitary discrete Hadamard transform by means of the paired transform is given. It is proved that to compute the N-point transform only O(N) addition-subtraction operations are necessary }, keywords={ computational complexity Hadamard matrices Hadamard transforms matrix decomposition vectors Hadamard matrix decomposition orthogonal vectors paired algorithm 1D Hadamard transform computation classical algorithm Walsh-Hadamard fast transform addition operations 1D unitary discrete Hadamard transform paired transform addition-subtraction operations N-point transform }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Atmaca96, author={Atmaca, H. and Bulut, M. and Demir, D. and Pazar, S.}, title={ A new fuzzy Kohonen clustering network based on histogram for image segmentation }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={845-9 vol.2}, abstract={ The fuzzy Kohonen clustering network (FKCN) algorithm is proposed for image segmentation. However, for iterative operations this algorithm takes a very long time. Therefore, care has been taken in order to make the FKCN algorithm realistically useful for image segmentation. A new FKCN algorithm has been developed which is based on an image histogram. Theoretical analysis and experimental results show that computing time is decreased and the proposed FKCN is a successful algorithm for image segmentation }, keywords={ computational complexity fuzzy neural nets image segmentation pattern recognition self-organising feature maps fuzzy Kohonen clustering network algorithm image segmentation image histogram iterative operations computing time }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Babaev96, author={Babaev, A. and Guler, B.}, title={ Adequacy theorems for fuzzy models }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={837-44 vol.2}, abstract={ Adequacy fuzzy systems for classic logical inference rules are investigated and necessary conditions are stated. The problem is considered by regarding input and projection using variations and necessary theorems are proved. An application of these theorems is discussed }, keywords={ fuzzy logic fuzzy systems inference mechanisms theorem proving adequacy fuzzy systems classic logical inference rules adequacy theorems fuzzy models input projection variations theorem proving }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Benslimane96, author={Benslimane, A.}, title={ On the use of reachability graph for protocols analysis }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={827-36 vol.2}, abstract={ In a complete protocol design process, it is often important to validate the protocol for general correctness properties such boundedness, deadlock and unspecified reception freedom. Reachability analysis has proved to be one of the most effective methods for protocol validation based on the state transition model. Consequently, many protocol validation tools have been built based on the technique of reachability analysis. The author presents the VALIPRO (Validation of Protocols) validation tool for communication protocols modeled as a number of communicating finite states machines. It allows a user-friendly and graphic introduction of automata and proposes four methods of validation. Deadlocks, unspecified receptions, blocking reception states, and capacity overflow are detected by this tool }, keywords={ computer graphics finite state machines formal specification formal verification protocols reachability analysis protocol analysis reachability graph protocol design protocol validation correctness properties boundedness deadlock unspecified reception freedom reachability analysis state transition model VALIPRO validation tool communication protocols communicating finite states machine automata graphical method blocking reception states capacity overflow }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Korver96, author={Korver, H. and Sellink, M.P.A.}, title={ On automating process algebra proofs }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={815-25 vol.2}, abstract={ Groote and Springintveld (1995) incorporated several model-oriented techniques-such as invariants, matching criteria, state mappings-in the process-algebraic framework of mu CRL for structuring and simplifying protocol verifications. The authors formalise these extensions in Coq, which is a proof development tool based on type theory. In the updated framework, the length of proof constructions is reduced significantly. Moreover, the new approach allows for more automation (proof generation) than was possible in the past. The results are illustrated by an example in which they prove two queue representations equal }, keywords={ formal verification process algebra protocols queueing theory theorem proving type theory automated process algebra proofs model-oriented techniques invariants matching criteria state mappings mu CRL protocol verification structuring protocol verification simplification Coq proof development tool type theory proof construction length proof generation queue representations }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Moreaux96, author={Moreaux, P.}, title={ Combining aggregation and decomposition methods for performance evaluation of complex systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={805-14 vol.2}, abstract={ To reduce the complexity of computation of performance indices of parallel systems, the author presents a new exact method combining the aggregation and decomposition methods of the state space. Aggregation is performed by the use of the stochastic well-formed net (SWN) Petri net model and decomposition follows tensor methods initiated by Plateau (1985). The author generalizes previous work to provide results for asynchronous as well as synchronous composition of submodels. The author highlights the problems of such an approach and derives necessary conditions on the modelled systems that allow for the two methods to be combined. For parallel systems satisfying these necessary conditions, models with corresponding algorithms are developed }, keywords={ Markov processes parallel algorithms Petri nets software performance evaluation decomposition methods aggregation methods performance evaluation computational complexity performance indices parallel systems complex systems state space stochastic well-formed net tensor methods asynchronous submodel composition synchronous submodel composition algorithms Petri net model }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Abdulla96, author={Abdulla, P.A. and Kindahl, M.}, title={ Using lossy channel systems for the verification of communication protocols }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={793-803 vol.2}, abstract={ The authors consider the class of finite-state systems communicating through unbounded but lossy FIFO channels (called lossy channel systems). These systems have infinite state spaces due to the unboundedness of the channels. Lossy channel systems are able to model e.g. link protocols such as the alternating bit protocol, HDLC, and the bounded retransmission protocol. In an earlier paper, they showed that the problems of checking reachability, safety properties, and eventuality properties are decidable for lossy channel systems. The decidability results were obtained under the assumption that message delivery through a channel may take an arbitrary amount of time. They consider a variant of lossy channel systems where message deliveries have zero delays. This new model allows one to analyze new classes of protocols which are not covered by the original model }, keywords={ decidability formal verification losses protocols safety telecommunication channels communication protocol verification finite-state systems lossy FIFO channels unbounded FIFO channels lossy channel systems infinite state spaces link protocols alternating bit protocol HDLC bounded retransmission protocol reachability safety properties eventuality properties decidability message delivery zero delays }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Inal96, author={Inal, H. and Ersoy, C.}, title={ A heuristic approach for finding the minimum delay spanning tree in topological design of interconnected LANs }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={785-91 vol.2}, abstract={ As the use of local area networks (LANs) increases, the need for interconnecting LANs has become an important topic. Some of the reasons for interconnecting LANs are obtaining higher reliability, security, and performance, and to increase the number of stations supported. Bridges are data link layer devices that store and forward frames between similar or dissimilar LANs. The paper describes a heuristic algorithm for finding a minimum delay spanning tree that is used by transparent bridges to interconnect LANs. The interconnected network is represented as a graph in which nodes correspond to LANs to be interconnected. The edges selected in the graph to form a tree correspond to connections provided by transparent bridges. In order to measure the quality of the solutions, the authors found the global minimum for small size problems. The algorithm finds solutions very close to the global minimum for small size problems. For larger size problems, they created 5000 trees that satisfy constraints for 15, 20 and 30 nodes to show that the heuristic algorithm will give better solutions than randomly selected trees. They tested the algorithm for various size problems to evaluate its time complexity. The time analysis gave O(n/sup 2/) complexity }, keywords={ computational complexity computer network reliability LAN interconnection local area networks security trees (mathematics) interconnected LANs topological design minimum delay spanning tree local area networks reliability security performance stations data link layer devices heuristic algorithm transparent bridges graph nodes edges small sized problems global minimum constraints time complexity time analysis }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Billionnet96, author={Billionnet, A. and Costa, M.-C. and Wei-Ying Thang}, title={ Task allocation and computing architecture optimization. An application at EDF }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={775-84 vol.2}, abstract={ The purpose of this article is to place the task allocation problem in a computing architecture design concept. This problem is the main concern of EDF (Electricite de France) engineers in charge of validating, and even optimizing, computing architectures by simulation. We describe the design process and we specify the types of applications and architectures concerned with our study. Then, we present an application concerning the design of an electricity control and monitoring system and we propose a model of the tasks, the databases and the links. We have selected two criteria to evaluate the quality of an allocation: a balanced distribution of "loads" between the processors and a limited use of the communication lines. We associate a mathematical model with the problem and we solve it using a simulated annealing heuristic }, keywords={ computerised monitoring database management systems electricity supply industry heuristic programming parallel architectures power system control resource allocation simulated annealing virtual machines task allocation computing architecture optimization EDF simulation electricity control electricity monitoring system databases quality load balancing communication lines mathematical model simulated annealing heuristic }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kasapoglu96, author={Kasapoglu, H. and Erdogan, N.}, title={ DRM: distributed raw-data manager }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={771-4 vol.2}, abstract={ The paper presents the logical implementation of shared memory on a physically distributed memory system. A collection of workstations connected by an Ethernet network serves as the platform of implementation. DRM-distributed raw-data manager-is a software tool that provides the distributed shared data paradigm at user-level, through run-time library routines. It combines the general and convenient programming model of shared memory systems with the computing power of distributed memory systems, hiding the details of data distribution and communication management required by the message passing model }, keywords={ distributed memory systems local area networks message passing parallel programming shared memory systems workstations DRM distributed raw-data manager shared memory physically distributed memory system workstations Ethernet network software tool user-level distributed shared data paradigm run-time library routines programming model data distribution communication management message passing model }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Khan96, author={Khan, A.S. and Simonenko, V. and Pham Hong Hanh}, title={ Theoretical adding for solving problem of maximum matching in distributed systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={759-69 vol.2}, abstract={ The paper provides a theoretical basis that supports a new approach for solving the assignment problem in dynamic scheduling in distributed systems. The key idea of the approach is to divide the process of scheduling into preliminary analysis of initial data and finding the solution with the support of the results of this analysis. The analysis algorithm is built on the principle of step-by-step forming and is called adaptive multi-analyzing algorithm (AMA). This algorithm is based on theoretical task assignment. The time complexity of the proposed algorithm varies from O[Nlog(N)+E] to less. The adding of this algorithm based on their theoretical system for analyzing initial data allows them to decrease the whole time complexity for finding the schedule of jobs and resources. These advances of AMA are shown using the results of experiments in the simulation of multiprocessing systems as well }, keywords={ computational complexity distributed algorithms multiprocessing systems processor scheduling virtual machines maximum matching distributed systems assignment problem dynamic scheduling theoretical adding initial data analysis step-by-step forming adaptive multi-analyzing algorithm task assignment time complexity job scheduling resource scheduling multiprocessing system simulation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Coppa96, author={Coppa, F. and Nardelli, E. and Talamo, M.}, title={ Discrete representation of spatial relations }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={749-58 vol.2}, abstract={ The authors show how to represent spatial objects in discrete space so that testing of containment and intersection relations between objects in the continuum can be done correctly. They characterize containment and intersection relations between spatial objects in terms of containment and intersection between sets of points of Z/sup 2/. The model is based on a mapping from spatial objects in real space to their representations in the discrete world such that topological relations on spatial objects are preserved. The mapping makes reference to a suitable topology whose underlying set is a canonical decomposition of the real plane in square cells }, keywords={ database theory geographic information systems spatial data structures topology visual databases spatial relations discrete representation spatial object representation discrete space containment relation testing intersection relation testing continuum containment relations intersection relations real space topological relations canonical decomposition real plane square cells }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cak96, author={Cak, S. and Ersak, A.}, title={ Fuzzy c-means clustering based color selection in ray tracing }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={745-8 vol.2}, abstract={ Color selection from a ray tracer output is normally made by using the output image histogram for finding the frequently used colors in the image. Although the execution time is short in using the histogram method, the image quality visually degrades in return. The fuzzy c-means clustering algorithm can alternatively be used for the color selection in order to reduce the level of image quality degradation. The study, based on the fact that dominant peaks of the histogram are almost equal to the fuzzy centroids of clusters, takes the histogram peaks as iteratively determined fuzzy centroids of FCM. This reduces the computational burden in FCM and besides that it improves the overall performance }, keywords={ colour graphics fuzzy set theory image colour analysis ray tracing fuzzy c-means clustering based color selection ray tracing ray tracer output fuzzy c-means clustering algorithm image quality degradation dominant histogram peaks iteratively determined fuzzy centroids performance }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Sarfraz96, author={Sarfraz, M.}, title={ An alternative to the NURBS of degree three }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={735-44 vol.2}, abstract={ A constructive approach is adopted to build a B-spline-like basis for a rational cubic spline with a cubic numerator and quadratic denominator. This formulation is quite useful for producing well controlled shape effects when compared to th NURBS and it does work as an alternative to the NURBS (the author calls it ANURBS). This ANURBS method is also a C/sup 2/ alternative to the GC/sup 2/ v-splines and the Gamma splines. The method for evaluating this rational cubic B-spline curve is suggested by a transformation to Bernstein-Bezier form. A comparative study, regarding the better shape control as compared to the NURBS, is also made }, keywords={ CAD CAD/CAM curve fitting engineering graphics splines (mathematics) degree three NURBS B-spline-like basis rational cubic spline cubic numerator quadratic denominator shape effects ANURBS method GC2 v-splines Gamma splines rational cubic B-spline curve Bernstein-Bezier form }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cuppens96, author={Cuppens, F. and Gabillon, A.}, title={ A query language for a multilevel object-oriented database }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={723-34 vol.2}, abstract={ The paper proposes a formal model for answering queries in a multilevel object-oriented database (OODB). The MultiView model is a multilevel security model for an OOBD. It provides a user cleared at a given security level with a consistent and complete view of the multilevel OODB corresponding to her clearance level. The formal definition of the MultiView model is based on first-order logic. An OODB secured with the MultiView model is associated with its own logical theory. The authors show how the first-order language they defined can be used to query a multilevel OODB secured with the MultiView model }, keywords={ authorisation object-oriented databases query languages query processing multilevel object-oriented database formal model query answering query language MultiView model multilevel security model security level clearance level first-order logic logical theory first-order language }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Bayram96, author={Bayram, Z.O. and Bryant, B.R. and Altmay, U.}, title={ ROSE: a practical higher-order functional/logic language }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={713-22 vol.2}, abstract={ The authors present a higher-order functional/logic language, ROSE. The programs of ROSE are made up of conditional constructor based term rewriting systems. The conditions in the rules can optionally be committing. The operational semantics of the language is conditional narrowing, augmented to deal with committing conditions. The major innovation of the language is the use of committing guards and backtracking to make possible very practical, operationally oriented programs. They show many practical examples, one of which is the definition of the extra logical function not, which implements the negation-as-finite-failure rule in the context of functional/logic programming }, keywords={ backtracking computational linguistics functional languages functional programming logic programming logic programming languages rewriting systems higher-order functional/logic language ROSE language ROSE programs constructor based term rewriting systems operational semantics conditional narrowing committing conditions committing guards backtracking operationally oriented programs not logical function negation-as-finite-failure rule functional/logic programming }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Gaibisso96, author={Gaibisso, C. and Nardelli, E. and Proietti, G.}, title={ Incremental constraints maintenance in concurrent logic programming }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={703-12 vol.2}, abstract={ The authors consider an algorithmic problem related to the incremental maintenance of constraints in a context of concurrent constraint logic programming (CC). They consider CC languages defined on symbolic, non-structured finite domains, where concurrent agents working on different sets of constraints define different partitions into equivalence classes over the universe of feasible values. An equivalence class of a partition contains the values which are equivalent as far as the satisfaction of the related set of constraints is concerned. The problem of knowing which are the equivalence classes with respect to the various agents can be modelled by means of a variant of the well-known disjoint set union problem. They introduce a data structure for such a variant which leads to an optimal worst case cost in dealing with the new defined operation, paying a cost which is proportional to the size of the returned intersection. They also provide the conditions under which the introduced data structure has better performances than the extension of classical approach for the set union problem }, keywords={ constraint handling data structures equivalence classes logic programming languages parallel languages parallel programming incremental constraints maintenance concurrent constraint logic programming algorithmic problem concurrent constraint logic programming languages symbolic nonstructured finite domains concurrent agents equivalence classes feasible values disjoint set union problem data structure optimal worst case cost returned intersection }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cavusoglu96, author={Cavusoglu, A. and Demirer, M. and Cayir, H.}, title={ A multi-lingual system for teaching programming language constructs }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={699-702 vol.2}, abstract={ One of the major problems of lecturers is teaching beginners programming language constructs. To overcome this problem a reconfigurable user friendly interpreter has been developed. The system allows users to change the interpreted graphical language which is used to solve maze problems formed by the user. The user has the freedom to change the language which is targetted to teach programming constructs similar to Pascal. At the moment the user can either use Turkish or English (predefined) for programming. In other cases, the user has to input the keywords for the new language (i.e. French, German etc.) to match their English equivalents }, keywords={ computer science education program interpreters teaching visual languages multi-lingual system programming language construct teaching reconfigurable user friendly interpreter interpreted graphical language maze problems Pascal Turkish language English language keywords }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Karaman96, author={Karaman, F.S.}, title={ Building a multimedia Web site by using JAVA and JAVA applets }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={693-8 vol.2}, abstract={ The answer to the question what makes the World Wide Web so powerful is that the client-side calculations frees the server from dependence on the client's operating system. It makes the Web simultaneously system independent and a minimal consumer of the bandwidth. By creating a standard way to transmit functions, not just data, over network lines, the reliability and authority of the server database can be used with the power of the client computer so that the Web will not be just an information publishing network-as it was during its short history-but a universal database. In this study the usage in multimedia environments of one tool (JAVA), which is well on its way to perform these changes, is examined. JAVA is a programming language (akin to C++) developed specifically for the Web by SUN Microsystems. Java applets-small applications built for specific tasks-are compact and platform independent, or rather dependent only on whether client's platform's browsers support the language. Web developers are going to be able to link applets to HTML documents, effectively turning the browser into an ad hoc application window. So the study covers building a Web site for a well known local Rock band including multimedia applications such as using sound (five songs of the band), video (an interview with the members of the band) and so on using JAVA and JAVA applets }, keywords={ Internet multimedia systems object-oriented languages object-oriented programming multimedia Web site JAVA applets World Wide Web client-side calculations system independent server database client computer information publishing network universal database multimedia environments JAVA programming language Web developers HTML documents browser ad hoc application window local Rock band multimedia applications video }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Oyman96, author={Oyman, E.I. and Ersoy, C.}, title={ Multipoint communication in multimedia applications }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={685-91 vol.2}, abstract={ Choosing a route that minimizes the network cost between multicasting parties is a decision problem which is closely related with the Steiner tree problem (STP), and is known to be NP complete. Several heuristics have been proposed for solving STP that run in polynomial time and result in reasonable solutions. However, they have the drawback that they are not designed for multimedia applications which require certain quality of service (QoS) guarantees. We investigate the success of simulated annealing (SA) for solving this problem. We experimented with example problems of different size and obtained promising results }, keywords={ computational complexity minimisation multimedia communication multimedia computing simulated annealing trees (mathematics) multipoint communication multimedia applications network cost minimisation multicasting parties decision problem Steiner tree problem STP NP complete polynomial time quality of service QoS guarantees simulated annealing }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Brown96, author={Brown, J.C. and Chase, M.R. and Cooper, M.A. and Kirkwood, P.J. and Sadik, A.K.}, title={ A Postscript document management system }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={675-84 vol.2}, abstract={ Postscript is an ideal, as yet unexplored storage format for document management: its advantages are listed in comparison with raster files, and with text marked up with SGML or HTML. A prototype system is described, written in 20,000 lines of C and interfacing to the portable Display Postscript interpreter and X Graphics User Interface. Screen snapshots show the document catalogue, Boolean query facility on author, title and document text, the document viewer and automatically generated contents list and alphabetic index. An interactive graphical reading path solves the "lost in hyperspace" problem, and a browsable semantic network supports users, unsure of the exact query terms they seek. Indexing performance data is presented for a large document. Analysis methods for indexing Postscript are discussed, and a general method, with acceptable indexing time, is proposed for Postscript coming from any source. The wider applicability of these techniques is discussed }, keywords={ desktop publishing indexing information retrieval page description languages Postscript document management system storage format C portable Display Postscript interpreter X Graphics User Interface document catalogue Boolean query facility document viewer automatically generated contents list alphabetic index interactive graphical reading path lost in hyperspace problem browsable semantic network query terms indexing performance data indexing time }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{McNeill96, author={McNeill, M.D.J. and White, M. and Lister, P.F.}, title={ Graphics codesign for multimedia systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={667-74 vol.2}, abstract={ The design of graphics systems for multimedia applications requires a wealth of considerations regarding hardware/software trade-offs and price/performance issues. Often a family of architectures is designed to cover a broad range of performance abilities and provide a clear path for future products. We present a codesign environment targeted specifically at the graphics accelerator market. GALADRIEL allows the design, test and simulation of architectures on the desktop using a library of reusable components and technology databases. Each functional component has one or more implementations (in software and/or a high level hardware description language) and associated performance metrics to permit the investigation of price/performance issues at a number of stages throughout the design process. A novel cosimulation technique is employed to verify designs }, keywords={ computer graphic equipment computer graphics hardware description languages high level synthesis multimedia computing software reusability graphics codesign multimedia systems graphics systems design multimedia applications hardware/software trade-offs price/performance issues performance abilities future products codesign environment graphics accelerator market GALADRIEL reusable components technology databases functional component high level hardware description language performance metrics design process novel cosimulation technique design verification }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Davenport96, author={Davenport, D.}, title={ On computation and its relation to cognition }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={657-66 vol.2}, abstract={ Many people now view the human mind as a sort of computer, but what exactly does that entail? The paper examines the general notion of computation and its relationship to cognition. The necessarily functional perspective that it presents, is shown to be coherent with the arguments of J. Searle (1990; 1992) and S. Harnad (1995). One interesting consequence of these views is that the concept of formal symbol systems is seen to be compatible with computation in general, including connectionism, not just the symbolic view it is normally associated with }, keywords={ artificial intelligence cognitive systems neural nets philosophical aspects cognition human mind computation functional perspective formal symbol systems connectionism symbolic view artificial intelligence philosophical foundations chinese room symbol grounding }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Ucoluk96, author={Ucoluk, G.}, title={ Level of consciousness as an evaluation criteria for natural and artificial intelligence: a life independent approach }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={651-5 vol.2}, abstract={ It is argued that a false value assertion is made by referring to Life' as valuable. Consciousness' is proposed instead. A Life' independent definition of consciousness' is given and the components for a measure of the level of consciousness' are introduced. A brief discussion follows on some ethical problems that arise }, keywords={ artificial intelligence philosophical aspects professional aspects social aspects of automation consciousness level evaluation criteria artificial intelligence natural intelligence life independent approach false value assertion life independent definition level of consciousness ethical problems }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cicekli96, author={Cicekli, N.}, title={ A temporal reasoning approach to knowledge-based simulations }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={641-50 vol.2}, abstract={ A simple logical framework for knowledge based simulation systems is presented. Special consideration is given to the simulation of systems which involve discontinuous change. An abbreviated form of R.A. Kowalski and M. Sergot's (1986) event calculus is introduced as a basis for tackling the problem and it is extended first with a convention for representing causal laws, and then to include higher order persistence and potential events. A logic programming approach to the computational problem is adopted and a logic program presented which is efficient yet which retains many of the logical properties of the set of event calculus axioms. It is hoped that the framework described will serve as a basis of a rule based simulation system with temporal reasoning facilities }, keywords={ digital simulation knowledge based systems knowledge representation logic programming process algebra temporal reasoning temporal reasoning approach knowledge based simulation systems discontinuous change causal law representation higher order persistence potential events logic programming approach computational problem logical properties event calculus axioms rule based simulation system temporal reasoning facilities }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Turhan96, author={Turhan, M.}, title={ A GBML approach to DFA construction and its application to Turkish word inflection }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={627-40 vol.2}, abstract={ The construction of the grammar that accepts a given set of strings is a machine learning problem. In this work it has been shown that genetic based machine learning (GBML) can successfully be used in the generation of some grammars. A genetic algorithm (GA) engine is developed and Turkish word inflection which has an agglutinative nature, is used as the testbed for the proposed technique. Results for a subset of all word inflections, namely the noun inflections is presented }, keywords={ genetic algorithms grammars learning (artificial intelligence) natural languages word processing GBML approach DFA construction Turkish word inflection grammar generation strings machine learning problem genetic based machine learning genetic algorithm engine agglutinative nature noun inflections }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{El-Den96, author={El-Den, J.}, title={ Suitability of object oriented concepts for computer supported cooperative work }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={615-26 vol.2}, abstract={ The paper looks at computer supported cooperative work (CSCW) and how the object oriented (OO) concepts are introduced to facilitate many of the concerns that are still under research in CSCW. The paper also looks at an improved version of a previously presented model for CSCW (J. El-Den, 1995). The paper ends with an example for the model }, keywords={ abstract data types groupware object-oriented methods object-oriented programming object oriented concepts computer supported cooperative work CSCW OO concepts groupware object classes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Chi-Ming-Chung96, author={Chi-Ming Chung and Shih, T.K. and Shyy, D.Y. and Chun-Chia Wang}, title={ A graph-theoretical metric for object-oriented software complexity }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={603-14 vol.2}, abstract={ Software metrics are widely used to measure software complexity and assure software quality. However, research in the field of the software complexity of a class hierarchy has not yet been carefully studied. We introduce a novel factor named URI (Unit Repeated Inheritance) and an important method named ILT (Inheritance Level Technique) to realize and measure the object oriented software complexity of a class hierarchy. The approach is based on the graph theoretical model for measuring the hierarchical complexity in inheritance relations. The proposed metric shows that inheritance has a close relation to the object oriented software complexity and reveals that overuse of repeated (multiple) inheritance will increase software complexity and be prone to implicit software errors }, keywords={ graph theory inheritance object-oriented programming software metrics software quality graph theoretical metric object oriented software complexity software metrics software quality class hierarchy URI Unit Repeated Inheritance ILT Inheritance Level Technique graph theoretical model hierarchical complexity inheritance relations multiple inheritance implicit software errors }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Thevenoux96, author={Thevenoux, P. and Larouche, G. and Barrat, B.}, title={ Improving programming re-usability via an object oriented approach in multi-sensor system evaluation }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={597-601 vol.2}, abstract={ This paper presents an object-oriented approach used to manage the performance evaluation of a highly complex multi-sensor system. Emphasis is placed on the design phase using OMT and the concepts of inheritance and virtuality are put forward to stress the re-usability factor }, keywords={ infrared imaging inheritance object-oriented programming performance evaluation radar signal processing sensor fusion software reusability software reusability object oriented approach multisensor system evaluation object oriented programming performance evaluation design phase OMT inheritance virtuality radar IR camera range laser }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Van-Bommel96, author={Van Bommel, M.}, title={ Operations on incremental multiple inheritance hierarchies }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={589-95 vol.2}, abstract={ Emerging programming and database definition languages permit the declaration of multiple inheritance hierarchies. The efficient computation of lattice operations on hierarchies for large software systems is a difficult problem. Permitting incremental update of the hierarchy further complicates the issue. Presented is a technique for the efficient encoding of multiple inheritance hierarchies in an incremental fashion. The encoding builds a mapping to a Boolean lattice of binary words, leading to almost constant-time lattice operations. Contrary to earlier works only supporting subsumption computations, the operations of greatest lower bound (GLB) and least upper bound (LUB) are also supported }, keywords={ database languages database theory inheritance object-oriented databases object-oriented languages incremental multiple inheritance hierarchies programming languages database definition languages lattice operations large software systems Boolean lattice binary words constant-time lattice operations subsumption computations greatest lower bound least upper bound class hierarchy object oriented database }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Van-Der-Schoot96, author={Van Der Schoot, H. and Ural, H.}, title={ Deciding deadlock-freedom of daisy-chain protocols by fair reachability analysis }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={579-88 vol.2}, abstract={ A relief strategy called fair reachability analysis (Gouda and Han, 1985) is extended for the verification of daisy-chain protocols, which are defined in the communicating finite state machine model as networks of n>or=2 processes with a bidirectional, serial link structure. Fair reachability analysis is shown to decide the deadlock detection problem for daisy-chain protocols whose fair reachable global state space is finite. A sufficient condition for this finiteness is also given }, keywords={ concurrency control finite state machines formal verification protocols reachability analysis deadlock-freedom daisy-chain protocols fair reachability analysis protocol verification communicating finite state machine model bidirectional serial link structure deadlock detection problem }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Antonova96, author={Antonova, G.S.}, title={ MTIE estimations for different SONET/SDH synchronization network topologies }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={575-8 vol.2}, abstract={ Synchronization is always a problem of different layers in a distributed system. The essential SONET/SDH features, which are high-speed and pointer activity, cause problems in applying traditional solutions for clock synchronization offered for digital networks. This paper introduces the maximum time interval error (MTIE) estimations for different SONET/SDH synchronization network topologies. These estimations were done by experiments with the universal model of the synchronization network, obtained using a simulation method, which scientists have not applied before. The model consists of the primary reference source (PRS) model, slave clock model, represented by phase-locked loop (PLL), and synchronization link model. MTIE estimations were obtained for four different synchronization network topologies }, keywords={ clocks errors phase locked loops SONET synchronisation synchronous digital hierarchy timing SONET SDH synchronization network topologies distributed system pointer activity clock synchronization maximum time interval error estimations simulation method primary reference source model slave clock model phase-locked loop synchronization link model }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kutlu96, author={Kutlu, A. and Ekiz, H. and Baba, M.D. and Powner, E.T.}, title={ Implementation of "Comb" based wireless access method for control area network }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={565-73 vol.2}, abstract={ Wireless communication, within the context of industrial applications, is an important issue for accessing the sensors and actuators through a wireless channel. More importantly, the question of interest is to operate in the broadcast mode, where any node needs to receive the data from any other node within the coverage area of each other. In this paper, the "Comb" based wireless access method is implemented for the control area network (CAN) which is a half duplex, serial data communication protocol for automotive and industrial applications. In this scheme, the transmitter node generates a binary sequence-known as a comb-before the actual frame to solve the contention situation. If the message has a higher priority, it is transmitted before any other messages without cancelling the transmission. Following a general description of the control area network, the Comb based wireless access method is presented. The results obtained from the simulations are given }, keywords={ actuators binary sequences data communication industrial control protocols sensors wireless LAN Comb wireless access method control area network wireless communication industrial applications sensors actuators broadcast mode half duplex serial data communication protocol automotive applications transmitter node binary sequence simulations }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Calamoneri96, author={Calamoneri, T. and Petreschi, R.}, title={ Visual representations of Trivalent Cayley Interconnection Networks }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={555-64 vol.2}, abstract={ We deal with Trivalent Cayley Interconnection Networks and we present two new representations of them emphasizing their geometric characteristics, both on the three-dimensional space and on the bidimensional grid. Looking inside these representations, we solve two problems related to them: the optimal area layout and the shortest routing problem }, keywords={ geometry graph theory multiprocessor interconnection networks network routing optimisation visual representations Trivalent Cayley Interconnection Networks geometric characteristics three-dimensional space 3D space bidimensional grid optimal area layout shortest routing problem graph theory }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Altinay96, author={Altinay, O. and Tulunay, E. and Tulanay, Y.}, title={ On data organization, training strategy and network size when using neural networks for identification purposes }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={551-4 vol.2}, abstract={ Multilayer perceptrons are employed for nonlinear system identification. This short communication, which is a product of experience gained in such identification effort, presents comments on data organization, neural network training strategy and network complexity. Points discussed lead to justifiable results in general }, keywords={ backpropagation data handling feedforward neural nets identification multilayer perceptrons data organization training strategy network size neural networks network complexity multilayer perceptrons nonlinear system identification backpropagation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Birol96, author={Birol, I. and Hacinhyan, A. and Ziya Perdahct, N.}, title={ Choice of time steps in simulating chaotic systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={543-9 vol.2}, abstract={ Overflows caused by the positive Lyapunov exponents of chaotic systems are the principal source of error in their simulation. In this work, it is shown that the Wiesel (1993) algorithm for Lyapunov exponent calculation represents a system which exactly maintains an orthonormal basis for the tangent flow. The choice of simulation time steps for chaotic systems is also considered. Suggested bounds for the time step are validated for the Lorenz (1963) and Rossler (1976) systems }, keywords={ chaos error analysis integration Lyapunov matrix equations simulation time steps chaotic systems simulation positive Lyapunov exponents error Lyapunov exponent calculation orthonormal basis tangent flow numerical integration }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Genc96, author={Genc, I. and Guzelis, C.}, title={ One-dimensional signal recognition by two-dimensional dynamical arrays }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={535-42 vol.2}, abstract={ This paper gives a general approach to one-dimensional (1-D) signal recognition by means of two-dimensional (2-D) arrays of dynamical cells. The 2-D arrays are used for transforming feature signals obtained in a feature extraction stage into 2-D feature signals which are easy to be classified. The motivation of using 2-D dynamical arrays for 1-D signals is mainly biological. It is known that many biological neural networks in the cerebral cortex of the brain are indeed 2-D layers of dynamical neurons interconnected through lateral feedback and that they define some topological feature maps. Kohonen's phoneme map is such an example introduced as a simplification of the human auditory cortex. Another motivation comes from the fact that some 2-D artificial neural networks such as Kohonen's self organizing feature map are very suitable for nonlinear data projection to visualize high dimensional data in pattern recognition. This paper extends the classical recognition systems in two directions: the proposed 2-D arrays are dynamical as opposed to the existing algebraic ones allowing time varying signals; feature signals to be processed are extracted from 1-D signals by a transformation which might be nonlinear and/or dynamical. As a specific application acoustic alarm signal classification is presented in the paper, so that discrete wavelet transformation (DWT) is used for extracting feature signals and cellular neural networks (CMNs) as 2-D dynamical arrays }, keywords={ acoustic signal processing alarm systems arrays brain models cellular neural nets feature extraction pattern classification self-organising feature maps wavelet transforms one-dimensional signal recognition 1D signal recognition two-dimensional dynamical arrays 2D dynamical arrays feature signals feature extraction biological neural networks cerebral cortex brain cellular neural networks lateral feedback topological feature maps phoneme map human auditory cortex neural networks self organizing feature map nonlinear data projection pattern recognition data visualization time varying signals acoustic alarm signal classification discrete wavelet transformation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Gulmezoglu96, author={Gulmezoglu, M.B. and Keskin, M. and Barkana, A.}, title={ Isolated word-recognition with a neural network which extracts personal differences }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={527-34 vol.2}, abstract={ A voice signal contains psychological and physiological properties of the person as well as the dialect differences, the acoustical environment effects and the phase differences. For these reasons the same word uttered by different speakers can be very different. In this paper, a neural network (NN) is developed to extract the common properties of a spoken word which is represented as a vector. The inputs of the NN are formed from the Energy+Cepstral (ECEP) parameters which are derived from the time domain samples. The outputs of the NN are the elements of the common vector and this vector is used in isolated word recognition. The weights in the NN are the elements of the orthonormal vectors }, keywords={ neural nets psychology speech recognition vectors isolated word recognition neural network personal difference voice signal psychological properties physiological properties dialect acoustical environment phase difference vector time domain samples orthogonalization weights orthonormal vectors }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Sagiroglu96, author={Sagiroglu, S.}, title={ Identification of linear dynamic systems using multi-layered perceptrons }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={517-26 vol.2}, abstract={ The identification of dynamic systems can be carried out by means of feedforward neural networks or recurrent neural networks. Multilayered perceptrons, as feedforward networks, are versatile and relatively simple to implement. This paper describes the use of multilayered perceptrons to identify linear dynamic systems. Both the order and parameters of the systems to be identified are unknown. The structure of a neural network capable of dealing with systems of up to a given maximum order i is detailed. Such a network is termed an i-th order network. Results of computer simulations using a 5th-order network to identify systems of up to the 5th order are presented }, keywords={ control system analysis computing digital simulation feedforward neural nets identification linear systems multilayer perceptrons linear dynamic systems identification multilayered perceptrons feedforward neural networks unknown system order unknown parameters computer simulations 5th-order network backpropagation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Henson96, author={Henson, M.C.}, title={ Vernacular rules for general recursion }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={507-16 vol.2}, abstract={ We present rules for the informal construction of programs by general recursion and explore a proof-theoretic interpretation of these constructions within a non-extensional constructive theory of operations and types. We present a result (the adequacy theorem) which guarantees that interpretable constructions are correct. This work contributes to the study of informal mathematical arguments }, keywords={ programming theory recursive functions set theory vernacular rules general recursion informal program construction proof-theoretic interpretation nonextensional constructive theory operations types adequacy theorem interpretable constructions correctness guarantee informal mathematical arguments constructive set theory intensional semantics program derivation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Godskesen96, author={Godskesen, J.C.}, title={ Telecommunications service validation and interaction detection }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={495-505 vol.2}, abstract={ The major contribution of this paper is a technique that allows for early off-line validation of telecommunications services and detection of unintended interaction between them. The technique utilizes the standardized specification languages SDL (Specification and Description Language, MSC (Message Sequence Charts) and TTCN (Tree and Tabular Combined Notation), and the commercially available specification tools SDT and ITEX. Telecommunications services have traditionally been validated online by means of testing at a rather late stage in the development process. With the technique advocated in this paper, services may, as a supplement to the traditional approach, be validated and interaction detected already at the design phase. In the paper, we show how each of the services Call-Waiting and Call-Forward-on-Busy can be specified as an extension of the core telecommunications service Basic-Call. We indicate how service validation and test case generation from the validated service specifications can be carried out by tool support. Finally, we demonstrate how the derived test cases can be used for detecting service interaction on a combined specification of Call-Waiting and Call-Forward-on-Busy }, keywords={ formal verification project support environments specification languages telecommunication computing telecommunication services telephony telecommunications service validation unintended interaction detection early off-line validation standardized specification languages SDL MSC TTCN commercially available specification tools SDT ITEX design phase Call-Waiting Call-Forward-on-Busy Basic-Call service test case generation Specification and Description Language Message Sequence Charts Tree and Tabular Combined Notation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Hadj-Rabia96, author={Hadj-Rabia, N. and Habrias, H.}, title={ Formal specification from NIAM model: a bottom up approach }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={483-94 vol.2}, abstract={ Presents automatic techniques for generating B specifications from a NIAM (Natural-language Information Analysis Method) model. Specifications contain not only the data structure of the NIAM model but also some basic operations according to graphical constraints. We describe a bottom-up approach to specify the dynamic aspects of an information system. The use of this approach should help in finding ambiguities and deficiencies in the requirements specification and/or in the very high-level specification of transactions. It should contribute to improvements in the quality of the programs, because many errors can be detected before implementation (reification). Furthermore, this can considerably reduce the costs of testing and maintenance. We illustrate our approach with examples which show how the specification of our information system can be built through the specification of its subsystems }, keywords={ data structures error detection formal specification program testing software maintenance software quality transaction processing formal specification NIAM model bottom-up approach automatic B specification generation Natural-Language Information Analysis Method data structure basic operations graphical constraints information system dynamics ambiguities deficiencies requirements specification very high-level specification transactions program quality error detection reification software testing costs software maintenance costs implementation subsystem specification }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Drias96, author={Drias, H.}, title={ Counting and testing satisfiability }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={473-82 vol.2}, abstract={ In this paper, we propose a new algorithm for computing solutions of satisfiability. It is then slightly modified to solve the corresponding decision problem. Probabilistic analyses are performed and show average polynomial time complexity for both cases. A comparison with algorithm "IS" proposed by J. Franco (1986) and previous works on SAT show that our results outperform these other algorithms }, keywords={ computability computational complexity decision theory probability satisfiability testing decision problem probabilistic analyses average polynomial time complexity algorithm IS algorithm performance solution counting checking }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Turner96, author={Turner, K.J. and McClenaghan, A. and Chan, C.}, title={ Specification and animation of reactive systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={355-64 vol.1}, abstract={ SOLVE (Specification using an Object-based, LOTOS-defined, Visual language) is designed to allow formal requirements capture, particularly for reactive systems. The SOLVE language is object-based, and formally defined using LOTOS (Language Of Temporal Ordering Specification). SOLVE is supported by tools that allow direct visual animation of systems specified in this language. Animation is supported by translating a SOLVE specification automatically into a LOTOS specification, and then graphically simulating this. A further application is embodied in the XDILL tool that supports requirements specification and visual animation of digital logic circuits. Several illustrative SOLVE examples are given }, keywords={ computer animation data visualisation engineering graphics formal specification logic CAD logic circuits object-oriented languages specification languages visual languages reactive systems formal requirements capture specification object-based LOTOS-defined visual language SOLVE language direct visual animation automatic SOLVE specification translation LOTOS specification graphical simulation XDILL tool visual animation digital logic circuits }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Dalkilic96, author={Dalkilic, M.E.}, title={ Register and function unit binding in architecture synthesis }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={225-34 vol.1}, abstract={ One of the primary jobs in translating a behavioral specification into a register-transfer level architecture is binding. Typically, binding follows operation scheduling and is composed of three strongly interrelated NP-hard subtasks: function unit (FU) binding, register binding, and interconnect binding. Register binding (assignment of variables to registers) and FU binding (assignment of operations to function units) problems are addressed. Register and FU binding algorithms based on a bipartite matching model are presented. The goal is to find a binding which minimizes the hardware cost. The FU and register binding algorithms are implemented and they compare favourably to other approaches }, keywords={ computer architecture logic design processor scheduling architecture synthesis behavioral specification translation register-transfer level architecture function unit binding register unit binding operation scheduling NP-hard subtasks interconnect binding binding algorithms bipartite matching model minimized hardware cost }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Ozer96, author={Ozer, E. and Orencik, B. and Akyokus, S.}, title={ An imprecise interrupt handling scheme in superscalar processors }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={207-12 vol.1}, abstract={ An imprecise interrupt handling mechanism is proposed for superscalar processors which employ out-of-order issue and out-of-order execution policies to achieve high performance. The proposed scheme is based on inserting shadow latch stacks between stages of processor pipelines to save processor contexts. This scheme is especially useful to accommodate nested interrupts }, keywords={ interrupts pipeline processing reduced instruction set computing imprecise interrupt handling scheme superscalar processors out-of-order issue policies out-of-order execution policies high performance system shadow latch stacks processor pipelines processor context saving nested interrupts }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Giloi96, author={Giloi, W.K. and Lindemann, C. and Pletner, S.}, title={ Performance modeling of novel node architectures for multiprocessor systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={213-23 vol.1}, abstract={ We analyze the performance of several design alternatives for the node architecture of two innovative distributed memory parallel architectures: the 2-processor node of MANNA and the 4-processor node of META. The analysis is based on the use of deterministic and stochastic Petri nets. The MANNA node architecture features two processors, the application processor and the communication processor, which share the node memory via a bus. The aim of the META design is a node that allows for a multi-threaded architecture with several threads being executed in parallel. Therefore, the META node consists of several processors and several memory units connected through a crossbar. The purpose of the study is to provide a basis for the node design decisions by providing quantitative results concerning processor and memory utilization for several design alternatives. These quantitative results can also be utilized for the validation of results obtained by a detailed hardware simulation study }, keywords={ distributed memory systems multiprocessor interconnection networks multiprogramming parallel architectures performance evaluation Petri nets stochastic processes virtual machines performance modeling novel node architectures multiprocessor systems distributed memory parallel architectures two-processor node MANNA four-processor node META deterministic Petri nets stochastic Petri nets application processor communication processor bus multi-threaded architecture memory units crossbar node design validation hardware simulation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kant96, author={Kant, M.}, title={ The twisted d-cube and the folded hypercube, two interesting topologies for efficient routing }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={197-205 vol.1}, abstract={ In this paper, the problem of routing messages along a shortest path in the folded hypercube and the twisted d-cube is considered. Boolean routing schemes are proposed for them, and two algorithms are presented for the one-to-one routing on a shortest path between source and destination. The authors prove that the space complexity for the storage of the communication information is O(2/sup d/) bits for the twisted d-cube, and O(2/sup n/(n-s)) bits for the folded hypercube FHC(n) }, keywords={ Boolean functions communication complexity distributed algorithms graph theory hypercube networks message passing multiprocessor interconnection networks network routing twisted d-cube folded hypercube routing topology message routing shortest path Boolean routing schemes distributed algorithms one-to-one routing space complexity communication information storage }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Birecik96, author={Birecik, S. and Kurugollu, F.}, title={ Comparison of thresholding methods for morphological edge detection }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={193-6 vol.1}, abstract={ In this paper, the binary morphological edge detection method is compared with other well-known edge detection methods in the literature. Different thresholding methods are used to binarize test images, then morphological edge detection is performed on the resulting images, and the figure of merit for measuring the performance of the edge detector is calculated }, keywords={ edge detection mathematical morphology software performance evaluation thresholding methods binary morphological edge detection method image binarization figure of merit edge detector performance measurement }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Starovoitov96, author={Starovoitov, V.}, title={ On qualitative comparison of methods for low-level image processing }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={189-92 vol.1}, abstract={ A new measure of dissimilarity between grey-scale images is presented. It may be used for the comparison of algorithms devoted to the same task, like edge-preserving noise smoothing, restoration, edge detection or thresholding. We consider the requirements of the measure and propose a multilevel measure design. Each level of the measure calculation (pixel-to-pixel, pixel-to-window, window-to-window and image-to-image) is based on different distance values. Experimental results with real images illustrate the performance of the proposed measure as a comparator }, keywords={ image processing low-level image processing methods image dissimilarity measure grey-scale images algorithm comparison edge-preserving noise smoothing image restoration edge detection thresholding multilevel measure design pixel-to-pixel level pixel-to-window level window-to-window level image-to-image level distance values performance digital images method comparison }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Erdogan96, author={Erdogan, A. and Leblebicioglu, K. and Halici, U. and Atalay, V.}, title={ Extraction of optimal texture features by a genetic algorithm }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={183-8 vol.1}, abstract={ This paper describes an approach for the supervised segmentation of images. Optimal local texture features are determined by a genetic algorithm. Several feature measures, most of which are based on the co-occurrence matrix, are suggested as basic texture measures. In the training phase, optimum ranges of these measures are determined on an image containing known texture regions. The genetic algorithm is of the elitist type and employs "roulette wheel selection" with fitness scaling }, keywords={ feature extraction genetic algorithms image segmentation image texture matrix algebra optimal texture feature extraction elitist genetic algorithm supervised image segmentation local texture features feature measures cooccurrence matrix training phase optimum ranges known texture regions roulette wheel selection fitness scaling }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Ozcan96, author={Ozcan, E. and Mohan, C.K.}, title={ Simulated annealing and genetic algorithms for partial shape matching }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={173-81 vol.1}, abstract={ Partial shape matching may be viewed as an optimization problem, to be solved using methods such as simulated annealing (SA) and genetic algorithms (GAs). We apply and compare both these methods for matching input shapes with model shapes described in terms of features such as line segments and angles. The quality of matching is gauged using a measure derived from attributed shape grammars. Current results show that both SA and GAs succeed in the shape matching task. A GA is faster and yields the global optimum more often than the versions of SA implemented }, keywords={ attribute grammars genetic algorithms image matching simulated annealing simulated annealing genetic algorithms partial shape matching optimization input shape matching model shapes line segments angles matching quality attributed shape grammars global optimum pattern recognition attributed strings evolutionary computing }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kapus96, author={Kapus, T. and Brezocnik, Z.}, title={ Incorporating real time into a concurrent temporal logic of actions }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={163-72 vol.1}, abstract={ Although the temporal logic of actions (TLA) is not a real-time temporal logic by definition, it can be employed for specifying and verifying real-time properties by interpreting an ordinary variable of the logic as representing real time. Models of TLA formulae are state (and also action) sequences. We call a temporal logic, similar to TLA, whose models are some partially ordered state (and also action) sets, a "concurrent temporal logic of actions". Due to the structure of its models, an originally non-real-time concurrent temporal logic of actions cannot express real-time properties. This paper, however, shows that time can be incorporated into it by introducing a special variable }, keywords={ distributed algorithms formal specification formal verification real-time systems sequences set theory temporal logic concurrent temporal logic of actions real-time properties specification real-time properties verification state sequences action sequences partially ordered sets posets variable true concurrency partial order runs }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Levin96, author={Levin, V. and Bounimova, E. and Basbugoglu, O. and Inan, K.}, title={ A bilingual specification environment for software/hardware co-design }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={153-62 vol.1}, abstract={ A new bilingual specification environment consisting of the two languages SDL and S/R is described. The new design is based on the SDL-to-S/R compiler that was implemented at a previous phase and introduces the necessary interface semantics as restrictions on special SDL shell processes that encapsulate the interfaced S/R modules. The environment can be used in SW/HW co-design by involving the verification engine COSPAN geared to the S/R language specification }, keywords={ formal specification formal verification logic design program compilers specification languages systems analysis bilingual specification environment software hardware co-design SDL S/R specification languages compiler interface semantics shell processes verification engine COSPAN Specification and Description Language }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Zamulin96, author={Zamulin, A.V.}, title={ Algebraic specification of an Oberon compiler }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={143-52 vol.1}, abstract={ A case study of the application of the algebraic specification technique to the formal definition of a real-world-language compiler has been performed. The programming language Oberon has been chosen for the purpose. Some results of the study are presented in the paper. The main attention is given to the formal definition of compiler data structures and semantic functions mapping an Oberon program into a term of an abstract target machine }, keywords={ algebraic specification data structures object-oriented languages object-oriented programming program compilers algebraic specification Oberon compiler formal definition programming language compiler data structures semantic functions abstract target machine object oriented language }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Varpaaniemi96, author={Varpaaniemi, K.}, title={ Finding small stubborn sets automatically }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={133-42 vol.1}, abstract={ State space generation is often needed in the analysis of concurrent and distributed systems. The stubborn set method is one of the techniques that try to alleviate the state space explosion encountered in state space generation. An algorithm for finding a stubborn set having as few enabled transitions as possible is presented. The practicality of the algorithm is motivated with the aid of examples }, keywords={ distributed algorithms formal verification graph theory minimisation systems analysis stubborn set method state space generation concurrent systems distributed systems verification systems analysis state space explosion distributed algorithm graph theory minimisation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Ping-Kuen-Chen96, author={Ping-Kuen Chen and Gwo-Dong Chen and Jorng-Tzong Horng}, title={ A hierarchical view mechanism for supporting a navigation query in object-oriented databases }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={123-32 vol.1}, abstract={ When a manager in a company wants to know what is going on, he always needs to read the summary reports then goes on to different levels of detail for interesting areas found in the summary reports. However, managers usually cannot deal with a complex database schema and a sophisticated query language. Therefore, a hierarchical view mechanism and navigation query facilities are required so that a manager can just click buttons and find the data he wants. Existing database view mechanisms do not support this. We propose a hierarchical view mechanism for users to navigate and locate data from levels of summary data to levels of detail }, keywords={ business data processing human factors object-oriented databases query languages query processing user interfaces hierarchical view mechanism navigation query object-oriented databases manager company summary reports complex database schema query language database view mechanisms levels of detail }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Bostan96, author={Bostan, B. and Yazici, A.}, title={ UDOOM: uncertainty in deductive object-oriented data modeling }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={113-22 vol.1}, abstract={ Uncertainty modeling and manipulation is required in deductive object-oriented models to handle complex objects with uncertain properties. The authors propose a data model called UDOOM for not only representing complex objects and having deduction capabilities but also for handling uncertainty }, keywords={ deductive databases object-oriented databases uncertainty handling uncertainty modeling uncertainty manipulation deductive object-oriented data modeling complex object handling uncertain properties UDOOM data model complex object representation deduction capabilities }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Dogac96, author={Dogac, A. and Ozhan, G. and Kilic, E. and Ozcan, F. and Nural, S. and Mancuhan, S. and Dengi, C. and Koksal, P. and Halici, U. and Arpinar, B. and Evrendilek, C. and Sadjadi, V.}, title={ An interoperability infrastructure for developing multidatabase systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={103-12 vol.1}, abstract={ A multidatabase system (MDBS) allows the users to simultaneously access autonomous, heterogenous databases using a single data model and a query language. This provides for achieving interoperability among heterogeneous, federated DBMSs. The authors describe the interoperability infrastructure of a multidatabase system, namely METU interoperable DBMS (MIND). The architecture of MIND is based on the OMG distributed object management model. It is implemented on top of a CORBA compliant ORB, namely, ObjectBroker. The interface of the generic database object is defined in CORBA IDL and multiple implementations of this interface, one for each component DBMSs, namely, Oracle7, Sybase, Adabas D and MOOD (METU Object-Oriented Database System) are provided. The main components of MIND which are built on this infrastructure are a global query manager, a global transaction manager, a schema integrator, interfaces to supported database systems and a graphical user interface }, keywords={ distributed databases graphical user interfaces object-oriented databases open systems query languages query processing transaction processing multidatabase system development interoperability infrastructure simultaneous autonomous heterogenous database access data model query language federated DBMS METU interoperable DBMS architecture OMG distributed object management model CORBA compliant ORB ObjectBroker generic database object interface CORBA IDL interface Oracle7 Sybase Adabas D MOOD global query manager global transaction manager schema integrator graphical user interface }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Aniorte96, author={Aniorte, P. and Meyranx, J.}, title={ Terminological database design: an approach based on the use of conceptual graphs }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={93-102 vol.1}, abstract={ A considerable interest in terminological databases is emerging in many fields of research. Nevertheless, little work has been done on such databases. The authors' objective is to propose an approach for database design, based on the conceptual graph theory, which has the ability to model the semantics of an application domain, and which proves to be well-suited to the terminologist's approach }, keywords={ database management systems database theory graph theory nomenclature tree data structures terminological database design conceptual graphs semantics modelling }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Gultekin96, author={Gultekin, A. and Gokmen, M.}, title={ Adaptive shape from shading }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={83-92 vol.1}, abstract={ Extracting surface orientation and surface depth from one or more images is a classic problem in computer vision. Shape-from-shading (SFS) deals with the recovery of 3D shape from a single shaded image. The shape is recovered by minimizing an energy functional involving constraints such as smoothness. In this constrained problem, although the smoothness constraint helps to stabilize the minimization process, it pushes the reconstruction toward a smooth surface. The authors present a new adaptive shape-from-shading method which reduces this oversmoothing by controlling the smoothness spatially over the image space. In order to improve the quality of the reconstruction, they also integrated this adaptive SFS algorithm and photometric stereo technique to recover shape by using more than one input image. The new algorithm is robust, data driven and updates both the gradient field and height map simultaneously. A hierarchical implementation of the algorithm is used to speed up the iterative scheme. Typical SFS and photometric stereo results are given to illustrate the usefulness of the approach }, keywords={ computer vision image reconstruction stereo image processing surface orientation extraction surface depth extraction computer vision adaptive shape from shading 3D shape recovery shaded image minimized energy functional constraints smoothness reconstruction oversmoothing photometric stereo technique adaptive algorithm input image gradient field updating height map updating iterative scheme }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Cloppet96, author={Cloppet, F. and Stamon, G.}, title={ Analysis of images of cells with neurites }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={73-81 vol.1}, abstract={ The study is concerned with segmentation of cytological images and extraction of cellular entities in order to provide quantitative data about the number of cells in culture (statistical tests, morphology, model of evolution, etc....). This quantitative data is useful in biology to evaluate the consequences of the application of active substances on morphological changes and cellular viability. The authors have implemented algorithms to extract cell contours and to split and merge each contour in order to obtain individual cells at the end of the analysis process }, keywords={ biology computing cellular biophysics computational geometry edge detection image segmentation neurites cell image analysis cytological image segmentation cellular entity extraction quantitative data culture biology active substance application morphological changes cellular viability algorithms cell contour extraction contour splitting contour merging }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Carkacioglu96, author={Carkacioglu, A. and Yarman-Vural, F.T.}, title={ Markov random fields texture similarity }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={63-72 vol.1}, abstract={ The paper deals with a class of textures which can be represented by a Markov random fields (MRF) model. Although the MRF model has been successfully employed for many texture generation and classification problems, numerical studies indicate that the success of the results heavily depends on the texture type. Binary textures are generated by the MRF model and examined for various texture alphabets. The study introduces new concepts, namely, base clique, base clique chain and n/sup th/ order clique chain. These concepts are then used to define mean clique length (MCL) and clique standard deviation (CSD) as measures of texture. The association between the appearance of texture and the texture measures is investigated. The simulation experiments are performed on various texture alphabets to quantify the data type by using the MCL and CSD texture measures. The factors that shape the structure of the texture are investigated }, keywords={ image classification image texture Markov processes random processes Markov random fields model texture similarity texture generation texture classification texture type binary textures texture alphabet base clique base clique chain nth order clique chain mean clique length clique standard deviation texture measures simulation data type image processing }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Ekinci96, author={Ekinci, M. and Thomas, B.T.}, title={ Multi-camera vision-based navigation of autonomous road vehicles in complex road networks }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={53-62 vol.1}, abstract={ Presents a computer vision system for an autonomous road vehicle (ARV) that is capable of negotiating complex road junctions and intersections in real time. The roads are detected from a sequence of monochromatic images captured by a multi-video-camera. A model-based object approach is used for detecting the road junctions in images. In this approach, the results of a region-growing segmentation process and an edge detection process using edge segments are fused based on a model voting strategy to locate the road junction surface. A multi-camera vision-based re-orientation mode has been used to guide the ARV during the turning process. Results are presented for real road intersection images and performed on the experimental ARV in real time }, keywords={ computerised navigation edge detection image segmentation image sequences mobile robots real-time systems road vehicles robot vision sensor fusion traffic control multi-camera vision-based navigation autonomous road vehicles complex road networks computer vision complex road junctions road intersection images real-time computing monochromatic image sequence road detection multi-video-camera model-based object approach region-growing segmentation process edge detection process edge segments data fusion model voting strategy road junction surface location vision-based reorientation mode turning process }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Groote96, author={Groote, J.F. and van Maaren, H.}, title={ Equivalence of the concave optimisation method and d'Agostino's tableaux for propositional logic }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={41-51 vol.1}, abstract={ Both d'Agostino's (1992) tableau system and the optimisation of concave associated functions can be used to determine whether formulas in propositional logic are contradictory, satisfiable or tautological. Both systems have very different roots and appear incompatible at first sight: d'Agostino's tableau system comes from the realm of logic, while concave optimisation is a typical technique that stems from operations research. We show that both techniques are computationally equivalent, in the sense that they simulate each other polynomially regarding proof length and proof search }, keywords={ computability concave programming formal logic operations research theorem proving concave optimisation method tableaux propositional logic concave associated functions contradictory formulas satisfiable formulas tautological formulas operations research computationally equivalent techniques polynomial simulation proof length proof search }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Evans96, author={Evans, A.S.}, title={ An assertional verification method for Z specifications of concurrent systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={29-39 vol.1}, abstract={ Presents a a set of inference rules for formally proving safety and liveness properties of extended Z specifications of concurrent systems. The rules are based on assertional verification techniques but are implemented in W, the emerging deductive calculus for Z. Thus, they can be verified by existing Z proof tools. The techniques presented are suitable for specifying and verifying properties of a variety of concurrent systems types, including communication-based systems, as is illustrated by the simple buffer case study presented in this paper }, keywords={ calculus formal logic formal specification formal verification inference mechanisms multiprocessing programs multiprocessing systems safety assertional verification method extended Z specifications concurrent systems inference rules formal proof safety properties liveness properties W deductive calculus Z proof tools communication based systems buffer }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Orava96, author={Orava, F.}, title={ Formal analysis of a railway interlocking system }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={17-27 vol.1}, abstract={ A high-level specification of a railway interlocking system expressed in CCS is presented. Safety-critical properties are formulated in the modal mu -calculus and verified using the Concurrency Workbench. The main functionality of the system is to establish safe paths-train routes-through a railyard. The properties verified express that the routes established are indeed safe, and that if the conditions for a safe route are fulfilled, then that route will eventually be established }, keywords={ calculus of communicating systems formal specification formal verification railways safety signalling formal analysis railway interlocking system high-level specification CCS safety-critical properties verification modal mu -calculus Concurrency Workbench safe path establishment train routes railyard railway signalling automatic verification model checking process algebra }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Klaudel96, author={Klaudel, H. and Riemann, R.-C.}, title={ Consistent equivalence notion for a class of high level Petri nets }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={7-16 vol.1}, abstract={ This paper presents an equivalence relation and a set of transformation rules on a class of high-level Petri nets, called M-nets, which are designed as a compact high-level representation of Petri boxes (Best et al., 1992). Boxes are equivalence classes of labelled Petri nets. As the main result, it is shown that the set of transformation rules is complete with respect to the equivalence relation in the finite case }, keywords={ equivalence classes Petri nets consistent equivalence notion equivalence relation transformation rules high-level Petri nets M-nets compact high-level representation Petri boxes equivalence classes labelled Petri nets completeness finite case }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 /usr/tmp/citation.tmp.28355 @ARTICLE{ReisingDec96, author={Reising, S.C. and Inan, U.S. and Bell, T.F. and Lyons, W.A.}, title={ Evidence for continuing current in sprite-producing cloud-to-ground lightning }, journal={Geophysical Research Letters}, volume={23}, number={24}, year={1996}, month={Dec}, pages={3639-42}, abstract={ Radio atmospherics launched by sprite-producing positive cloud-to-ground lightning flashes and observed at Palmer Station, Antarctica, exhibit large ELF slow tails following the initial VLF portion, indicating the presence of continuing currents in the source lightning flashes. One-to-one correlation of sferics with NLDN lightning data in both time and arrival azimuth, measured with an accuracy of +or-1 degrees at \12,000 km range, allows unambiguous identification of lightning flashes originating in the storm of interest. Slow-tail measurements at Palmer can potentially be used to measure continuing currents in lightning flashes over nearly half of the Earth's surface }, keywords={ atmospherics lightning thunderstorms atmosphere troposphere electric field electric current continuing current sprite-producing cloud-to-ground lightning thunderstorm atmospherics positive cloud-to-ground lightning flash Palmer Station Antarctica large ELF slow tail source lightning flash sferics NLDN lightning }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Al-Ayyoub96, author={Al-Ayyoub, A.-E. and Day, K.}, title={ The hyperstar interconnection network }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={463-72 vol.1}, abstract={ A multiprocessor interconnection topology, the hyperstar, based on the Cartesian product of star graphs, is presented. The basic properties of the hyperstar are discussed and proved. These include reduced degree and diameter, hierarchical structure, vertex symmetry, optimal routing, and shortest path characterization. The hyperstar is shown to be a member of the Cayley class of symmetric graphs. Embeddings of hypercubes, star graphs, meshes, and Hamiltonian cycles are discussed. An optimal one-to-all broadcasting algorithm is obtained and analyzed. Furthermore, a comparative study between the hyperstar and seven related networks is also conducted. The comparison is based on scalability, communication cost, link requirements, cost/performance ratio, and other static parameters such as degree, diameter, and average diameter }, keywords={ broadcasting graph theory multiprocessor interconnection networks reconfigurable architectures hyperstar interconnection network multiprocessor interconnection topology Cartesian star graphs reduced degree reduced diameter hierarchical structure vertex symmetry optimal routing shortest path characterization Cayley symmetric graphs embedded hypercubes embedded star graphs embedded meshes Hamiltonian cycles optimal one-to-all broadcasting algorithm scalability communication cost link requirements cost/performance ratio static parameters average diameter }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Akgun96, author={Akgun, B.T. and Peksen, E. and Harmanci, A.E.}, title={ Heterogeneous task migration mechanism in BAG distributed real-time operating system }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={453-62 vol.1}, abstract={ The task migration facility of the distributed real time operating system, BAG, is presented. The SDL model has been selected as the real time programming model. The task migration mechanism of BAG which is essentially based on user level states, improves performance and also simplifies problems related to the continuity of message handling. This mechanism has been separately deviced for homogeneous and heterogeneous systems. The heterogeneous migration mechanism is specially emphasized }, keywords={ electronic messaging network operating systems programming real-time systems heterogeneous task migration mechanism BAG distributed real time operating system task migration facility SDL model real time programming model user level states message handling heterogeneous systems homogeneous systems heterogeneous migration mechanism }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Al-Mouhamed96, author={Al-Mouhamed, M. and Seiden, S. and Abu-Haimed, H.}, title={ Minimization of memory and network contention for accessing arbitrary power-of-2 data patterns }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={443-52 vol.1}, abstract={ Finding general XOR schemes to minimize memory and network contention for accessing arrays with arbitrary sets of data templates is presented. A combined XOR matrix is proposed, together with a necessary and sufficient condition for conflict free access. We present a new characterization of the baseline network. Finding an XOR matrix for combined templates is shown to be an NP complete problem. A heuristic is proposed for finding XOR matrices by determining the constraints of each template matrix and solving a set of simultaneous equations for each row. Evaluation shows significant reduction of memory and network contention compared to interleaving and to static row-column-diagonals storage }, keywords={ computational complexity matrix algebra memory architecture minimisation storage allocation storage management network contention memory contention minimisation arbitrary power-of-2 data pattern access XOR schemes arbitrary sets data templates combined XOR matrix sufficient condition conflict free access baseline network combined templates NP complete problem heuristic template matrix simultaneous equations }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Gul96, author={Gul, E.}, title={ A mathematical model for multiprocessor implementation of an algorithm }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={437-42 vol.1}, abstract={ A mathematical model is derived for a multiprocessor implementation of a target tracking algorithm. The practical implementation of this algorithm confirms the results obtained from the model. This analysis is useful to predict multiprocessor performance of an algorithm }, keywords={ military computing multiprocessing systems parallel algorithms target tracking mathematical model multiprocessor implementation target tracking algorithm practical implementation multiprocessor performance }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Gueaieb96, author={Gueaieb, W.}, title={ The practical significance of simple classification rules }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={427-36 vol.1}, abstract={ The author adopts the classification algorithm T2, derived by Auer et al. (1995), to show that simple classification algorithms, with decision trees of depth 2, usually lead to accuracies which are very close to those produced by complex ones, such as C4.5. As a consequence, the author suggests that T2 may be used as a challenging practical metric to evaluate the accuracies of complex classification algorithms. Furthermore, the author shows how to take advantage of the cases where decision trees, with low depth and number of leaves, produce close or higher accuracies than those with higher depth and number of leaves, by showing how to determine the relative relevance, and detect any possible redundancies among some of the attributes of the dataset in use }, keywords={ decision theory learning (artificial intelligence) pattern classification redundancy trees (mathematics) simple classification rules T2 classification algorithm simple classification algorithms decision trees depth 2 algorithms accuracies practical metric complex classification algorithms accuracy evaluation leaves relative relevance redundancies dataset }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Matwin96, author={Matwin, S. and Rouget, T.}, title={ Explainable induction with an imperfect qualitative model }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={415-25 vol.1}, abstract={ The paper addresses the problem of learning concept descriptions that are interpretable/explainable. Explainability is understood as the ability to justify the learned concept in terms of the existing background knowledge. The starting point for the work was an existing system that would induce only fully explainable rules. The system performed well when the model used during induction was complete and correct. In practice, however, models are likely to be imperfect, i.e. incomplete and incorrect. The authors report a new approach that achieves explainability with imperfect models. The basis of the system is the standard inductive search driven by an accuracy-oriented heuristic, biased towards rule explainability. The bias is abandoned when there is heuristic evidence that a significant loss of accuracy results from constraining the search to explainable rules only. The user can express their relative preference for accuracy vs. explainability. Experiments indicate that, even with a partially incomplete and/or incorrect model, insisting on explainability results in only a small loss of accuracy. They also show how the new approach can repair a faulty model using evidence derived from data during induction }, keywords={ explanation heuristic programming knowledge based systems learning by example search problems uncertainty handling imperfect qualitative model concept description learning explainable induction interpretability explainability background knowledge standard inductive search accuracy-oriented heuristic rule explainability constrained search accuracy partially incorrect model partially incomplete model faulty model repair evidence }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Arzu-Sigman96, author={Arzu Sigman, N. and Alpaslan, F.N. and Yarman Vural, F.T.}, title={ An Ottoman-Turkish transcription system }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={405-14 vol.1}, abstract={ A system for transcribing Ottoman text into modern Turkish alphabet is described. This system utilizes Ottoman text coded by ASCII characters as input. It is assumed that all the characters in the Ottoman text are recognized by an OCR system which outputs the Ottoman characters as ASCII-coded compound structures (i.e. subwords). All the compound structures that are obtained from the test documents are stored in a B+-tree which is named OCST (Ottoman Compound Structure Table). All the transcriptions are produced by the help of the Ottoman-Turkish dictionary, which is kept as a tree in the memory. The inner nodes of the tree are Ottoman compound structures and the leaf nodes are Turkish transcriptions. The output text composed of Turkish transcriptions is produced by processing the input }, keywords={ character sets computational linguistics linguistics optical character recognition tree data structures Ottoman-Turkish transcription system Ottoman text transcription modern Turkish alphabet ASCII characters OCR system ASCII-coded compound structures B+-tree Ottoman Compound Structure Table OCST Ottoman-Turkish dictionary inner tree nodes leaf nodes output text input processing }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Bayram96, author={Bayram, Z.O.}, title={ SSST (State-Space Search Tool): a probabilistic forward-chained expert system shell with full backtracking }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={395-404 vol.1}, abstract={ The author describes a probabilistic backtracking forward-chained expert system shell that performs a best-first search of the state-space consisting of working memory states. The state space that needs to be traversed can be narrowed significantly through tactful use of the context mechanism. Fail conditions detect forbidden working memory states and cause immediate backtracking. Heuristic information about which rules should have higher priority are encoded in the rules at the granularity level of condition elements in the form of importance factors. Facts in the working memory have associated with them confidence factors, which allows the representation of uncertain information. The paradigm that results as the combination of this specific set of features permits declarative specification of the state space required for the solution of many kinds of scheduling problems and other kinds of problems requiring intelligent search of the state space with possible backtracking }, keywords={ backtracking expert system shells forward chaining heuristic programming inference mechanisms probabilistic backtracking forward-chained expert system shell SSST State-Space Search Tool best-first state-space search working memory states context mechanism fail conditions forbidden working memory state detection heuristic information rule priority condition element granularity level importance factors confidence factors uncertain information declarative specification scheduling problems intelligent state space search }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Levin96, author={Levin, V. and Bounimova, E. and Inan, K.}, title={ An interface implementation using a formal compiler specification method }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={385-94 vol.1}, abstract={ The paper presents a new formal compiler specification method that has evolved out of a number of realistic applications including the current application reported in the paper and describes how it is used as a formal method tool for compiler design and implementation problems }, keywords={ application program interfaces formal specification program compilers formal compiler specification method formal method tool compiler design interface implementation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Bernardo96, author={Bernardo, M. and Donatiello, L. and Gorrieri, R.}, title={ A stochastic process algebra model for the analysis of the alternating bit protocol }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={375-84 vol.1}, abstract={ The authors illustrate an application of the integrated approach for modeling and analyzing concurrent systems proposed by the authors in 1995. The case study concerns the alternating bit protocol. The protocol is specified by means of a set of terms of the stochastic process algebra EMPA, and then studied from the functional and the performance point of view after constructing the semantic models associated with the terms }, keywords={ parallel processing Petri nets process algebra protocols software performance evaluation system monitoring stochastic process algebra model alternating bit protocol analysis integrated modeling/analysis method concurrent systems EMPA stochastic process algebra performance functional analysis semantic models }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Lilius96, author={Lilius, J. and Pelz, E.}, title={ An M-net semantics for B(PN)/sup 2/ with procedures }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={365-74 vol.1}, abstract={ The authors extend the M-net semantics for the concurrent programming language B(PN)/sup 2/, a high-level net semantics which is original by its full compositionality, to B(PN)/sup 2/ with procedures. To this end they introduce a procedure-box concept for M-nets. A procedure-box is a finite net with one entry and one exit place that represents a B(PN)/sup 2/ procedure. Procedure call and return is achieved through synchronization while the distinction between the different instances is done with structured tokens }, keywords={ computational linguistics parallel languages Petri nets process algebra synchronisation M-net semantics concurrent programming language B(PN)/sup 2/ with procedures high-level net semantics full compositionality procedure-box concept finite net exit place entry place procedure call synchronization structured tokens }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Tianruo-Yang96, author={Tianruo Yang}, title={ Parallel least squares problems on massively distributed memory computers }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={345-54 vol.1}, abstract={ The author studies the parallel aspects of PCGLS, a basic iterative method, the main idea of which is to organize the computation of a conjugate gradient method with pre-conditioner applied to normal equations, and incomplete modified Gram-Schmidt pre-conditioner for solving least squares problems on massively parallel distributed memory computers. The performance of these methods on this kind of architecture is always limited because of the global communication required for the inner products. The author describes the parallelization of the PCGLS and IMGS pre-conditioners using two methods of improvement. One is to assemble the results of a number of inner products collectively and the other is to create situations where communication can be overlapped with computation. A theoretical model of computation and communication phases is presented which allows one to decide the number of processors that minimizes the runtime. Several numerical experiments on Parsytec GC/PowerPlus are presented }, keywords={ conjugate gradient methods distributed memory systems least squares approximations parallel architectures parallel machines parallel least squares problems PCGLS iterative method conjugate gradient method pre-conditioner normal equations incomplete modified Gram-Schmidt pre-conditioner massively parallel distributed memory computers communication architecture parallelization inner products computation minimized runtime Parsytec GC/PowerPlus }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Al-Mouhamed96, author={Al-Mouhamed, M. and Al-Maasarani, A.}, title={ Performance evaluation of scheduling precedence-constrained computations on message-passing systems }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={337-44 vol.1}, abstract={ Scheduling precedence graphs with communication times is the theoretical basis for achieving efficient parallelism in message-passing machines. The lack of global information on the tasks, due to communication, has lead to develop local scheduling heuristics such as the earliest-task-first. Using knowledge on computation, communication, and system topology, a class of global priority-based scheduling heuristics called generalized list scheduling (GLS) is proposed. The task-level is evaluated by backward scheduling the computation over the multiprocessor by using the best local heuristic. This leads to realistic measurement of the task priority for use in forward GLS scheduling. Experimental evaluation of local and GLS heuristics is carried out using extensive random graph generation and altering over the communication, inherent parallelism, and system topology. Analysis shows that local heuristics rely on locally maximizing the processor efficiency and gives acceptable deviations from the best known solution only when the inherent parallelism is large enough to cover the effective communication. This leads the local heuristics to achieve bounded speedup. GLS scheduling is based on combining two strategies: (1) differentiate critical computation and communications from others by scheduling critical paths first, and (2) implement effective management of processor utilization in order to increase the speedup }, keywords={ message passing parallel processing performance evaluation processor scheduling precedence-constrained computation scheduling message passing systems performance evaluation precedence graph scheduling communication times efficient parallelism local scheduling heuristics earliest-task-first heuristics system topology global priority-based scheduling heuristics generalized list scheduling backward scheduling best local heuristic multiprocessor task priority measurement forward scheduling random graph generation inherent parallelism random graph alteration locally maximed processor efficiency bounded speedup critical path scheduling }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Al-Mouhamed96, author={Al-Mouhamed, M. and Seiden, S. and Abu-Haimed, H.}, title={ Array organization in lock-step parallel memories }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={327-36 vol.1}, abstract={ The serialization of memory accesses is a major limiting factor in high performance SIMD computers. The data patterns or templates that are accessed by a program can be perceived by the compiler and therefore, the design of dynamic storage schemes that minimize conflicts may dramatically improve performance. The problem of finding storage schemes that minimize the access time of arbitrary sets of power-of-2 data patterns is proved to be NP complete. We propose linear address transformations that can be dynamically applied by each processing element for mapping array references onto memories. An efficient approach for combining the constraints of different access patterns into one single linear address transformation is presented. We prove that finding the transformation that minimizes the access time is reduceable to N coloring, where N is the number of parallel memories. Using coloring heuristics, storage schemes that minimize overall memory access time are heuristically constructed. Evaluation shows that synthesized storages lead to dramatic reduction of the degree of conflict and largely outperforms interleaving and row-column-diagonals (STARAN) storages }, keywords={ computational complexity graph colouring memory architecture minimisation storage allocation storage management array organization lock step parallel memories memory access serialization high performance SIMD computers templates dynamic storage schemes power-of-2 data patterns NP complete linear address transformations processing element array references access patterns single linear address transformation access time minimisation N coloring coloring heuristics storage schemes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kant96, author={Kant, M.}, title={ Parallel algorithms for inferring evolutionary trees }, booktitle={Proceedings of the Eleventh International Symposium on Computer andInformation Sciences. ISCIS}, volume={}, number={}, year={1996}, month={}, pages={317-26 vol.1}, abstract={ Let S=»s/sub 1/,...,s/sub n/À be a set of n species n I, and C=»c/sup 1/,...,c/sup nu /À a set of p characters, p>1. Every character c' may have k, distinct values (states) c/sub 1/',...,c/sub k1//sup 1/.K/sub 1/>1. We denote by S', the set of species which have the value c/sub i/' for the character c/sup 1/, and by I, the set »S/sub 1/'¬11 MeV) runaway electron beams-accelerated in an avalanche process by quasi-electrostatic thundercloud fields. They consider the height-dependent density profile of the relativistic electrons specified as a function of time in the context of a previously reported runaway model [Bell et al., 1995]. The electron beam is modeled as a vertical cylinder with radius 10 km, and numerical estimates are provided of gamma -ray fluxes which would be observed at the satellite. The predicted fluxes at the satellite altitude and at horizontal distances of up to 500 km from the source are found to be comparable to the experimental data }, keywords={ atmospheric electricity atmospheric radiation gamma-rays lightning thunderstorms atmosphere storm thunderstorm gamma ray emission gamma -ray emission relativistic electron beam runaway electrons quasi-electrostatic field electric field lightning high energy photons BATSE CGRO gamma ray burst bremsstrahlung avalanche process relativistic electrons runaway model vertical cylinder gamma -ray flux }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{FukunishiAug96, author={Fukunishi, H. and Takahashi, Y. and Kubota, M. and Sakanoi, K. and Inan, U.S. and Lyons, W.A.}, title={ Elves: lightning-induced transient luminous events in the lower ionosphere }, journal={Geophysical Research Letters}, volume={23}, number={16}, year={1996}, month={Aug}, pages={2157-60}, abstract={ Observations of optical phenomena at high altitude above thunderstorms using a multichannel high-speed photometer and image intensified CCD cameras were carried but at Yucca Ridge Field Station (40 degrees 40' N, 104 degrees 56' W), Colorado as part of the SPRITES'95 campaign from 15 June to August 6, 1995. These new measurements indicate that diffuse optical flashes with a duration of <1 ms and a horizontal scale of À100-300 km occur at 75-105 km altitude in the lower ionosphere just after the onset of cloud-to-ground lightning discharges, but preceding the onset of sprites. Here we designate these events as "elves" to distinguish them from "red sprites". This finding is consistent with the production of diffuse optical emissions due to the heating of the lower ionosphere by electromagnetic pulses generated by lightning discharges as suggested by several authors }, keywords={ atmospheric radiation atmospheric temperature electromagnetic pulse ionospheric disturbances lightning thunderstorms lightning-induced transient luminous events lower ionosphere thunderstorms SPRITES'95 campaign diffuse optical flashes cloud-to-ground lightning discharges elves heating electromagnetic pulses AD 1995 06 15 to 08 06 75 to 105 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GlukhovAug96, author={Glukhov, V.S. and Inan, U.S.}, title={ Particle simulation of the time-dependent interaction with the ionosphere of rapidly varying lightning EMP }, journal={Geophysical Research Letters}, volume={23}, number={16}, year={1996}, month={Aug}, pages={2193-6}, abstract={ The interaction with the lower ionosphere of rapidly varying electromagnetic pulses (EMPs) produced by lightning discharges is studied. The nonlinear heating, ionization and optical emission production are modeled using the Monte Carlo technique, which allows for consideration of realistic lightning EMPs with a few mu s rise times. Results indicate that the electron distribution function is highly anisotropic during the first few mu s of the interaction, but subsequently develops into a near-isotropic quasi-stationary state. The peak optical emissions intensities are found to be highly dependent on the EMP waveform, while the altitude range at which the emissions occur is relatively independent of pulse shape. Results of the particle simulation are used to assess the range of applicability of the quasi-stationary models [Taranenko et al., 1993; Inan et al., 1996] }, keywords={ electromagnetic pulse ionospheric disturbances ionospheric electromagnetic wave propagation lightning EM pulse radiowave propagation ionospheric disturbance particle simulation time-dependent interaction ionosphere rapidly varying lightning EMP rapidly varying electromagnetic pulse nonlinear heating ionization optical emission Monte Carlo method anisotropic electron distribution function EMP waveform quasistationary model }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Lev-TovJul96, author={Lev-Tov, S.J. and Inan, U.S. and Smith, A.J. and Clilverd, M.A.}, title={ Characteristics of localized ionospheric disturbances inferred from VLF measurements at two closely spaced receivers }, journal={Journal of Geophysical Research}, volume={101}, number={A7}, year={1996}, month={Jul}, pages={15737-47}, abstract={ The very low frequency (VLF) NPM signal from Hawaii was recorded at two closely spaced (À50 km) receivers (located at Palmer and Faraday stations) on the Antarctic Peninsula. Measurements of characteristic amplitude and phase signatures of lightning-induced electron precipitation (LEP) events were made on three different days in March 1992. Both amplitude and, for the first time, phase measurements are quantitatively interpreted using a three-dimensional model of VLF propagation in the Earth-ionosphere waveguide in the presence of lower ionospheric disturbances. This is the first time such a study has been undertaken with mirrored precipitation. Differences between the amplitude and phase changes at the two sites are accounted for by the location of the LEP ionospheric disturbance transverse to the VLF signal propagation paths. The change in these differences is explained by the horizontal movement of the disturbance region and, therefore, the causative whistler duct footprint across the transmitter-receiver paths. Trends in the amplitude and phase changes on a timescale of order 1 hour are found to be encompassed by the modeling of the passage of the day-night terminator along the paths }, keywords={ atmospheric electron precipitation Earth-ionosphere waveguide ionospheric disturbances ionosphere three-dimensional model AD 1992 03 localized ionospheric disturbance VLF two closely spaced receivers Antarctica amplitude phase signatures lightning-induced electron precipitation radiowave propagation Earth-ionosphere waveguide mirrored precipitation causative whistler duct footprint transmitter-receiver path day-night terminator passage }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Inan15May96, author={Inan, U.S. and Pasko, V.P. and Bell, T.F.}, title={ Sustained heating of the ionosphere above thunderstorms as evidenced in ``early/fast'' VLF events }, journal={Geophysical Research Letters}, volume={23}, number={10}, year={1996}, month={May}, pages={1067-70}, abstract={ Quasi-electrostatic (QE) thundercloud fields are proposed to maintain the ionospheric electrons at a persistently heated level well above their ambient thermal energy. Changes in the thundercloud charge (e.g., in lightning discharges) lead to heating/cooling above/below this quiescent level, and are registered as sudden (i.e., fast'<20 ms) subionospheric VLF signal changes, occurring simultaneously (i.e., early'<20 ms) with lightning discharges, and referred to as early/fast VLF events [Inan et al., 1993] }, keywords={ atmospheric radiation atmospheric temperature ionospheric disturbances lightning thunderstorms sustained heating ionosphere thunderstorms VLF events quasi-electrostatic thundercloud fields lightning discharges cooling subionospheric VLF signal changes }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Inan1May96, author={Inan, U.S. and Reising, S.C. and Fishman, G.J. and Horack, J.M.}, title={ On the association of terrestrial gamma-ray bursts with lightning and implications for sprites }, journal={Geophysical Research Letters}, volume={23}, number={9}, year={1996}, month={May}, pages={1017-20}, abstract={ Measurements of ELF/VLF radio atmospherics (sterics) at Palmer Station, Antarctica, provide evidence of active thunderstorms near the inferred source regions of two different gamma-ray bursts of terrestrial origin (Fishman et al., 1994). In one case, a relatively intense steric occurring within +or-1.5 ms of the time of the gamma-ray burst provides the first indication of a direct association of this burst with a lightning discharge. This steric and many others launched by positive cloud-to-ground (CG) discharges and observed at Palmer during the periods studied exhibit slow tail' waveforms, indicative of continuing currents in the causative lightning discharges. The slow tails of these sterics are similar to those of sterics originating in positive CG discharges that are associated with sprites }, keywords={ atmospheric radiation atmospherics lightning thunderstorms terrestrial gamma-ray bursts CGRO observations sprites ELF radio atmospherics VLF radio atmospherics sterics Palmer Station Antarctica active thunderstorms source regions lightning discharge positive cloud-to-ground discharges slow tail waveforms 300 Hz to 20 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoMar96, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Sprites as luminous columns of ionization produced by quasi-electrostatic thundercloud fields }, journal={Geophysical Research Letters}, volume={23}, number={6}, year={1996}, month={Mar}, pages={649-52}, abstract={ Quasi-electrostatic (QE) fields which exist above thunderclouds after lightning discharges can lead to the formation of columnar channels of breakdown ionization and carrot-like vertical luminous structures with typical transverse dimension À5-10 km spanning an altitude range from À80 km to well below À50 km. The carrot-like forms closely resemble those observed in sprites. Results indicate that the appearance of optical emissions can be significantly delayed in time (À1-20 ms) with respect to the causative lightning discharge }, keywords={ airglow atmospheric electricity atmospheric ionisation lightning mesosphere thermosphere thunderstorms middle atmosphere mesosphere upper atmosphere thermosphere stratosphere ionisation ionization sprite thunderstorm disturbance optical emission electric discharge luminous column quasi-electrostatic field electric field lightning columnar channel breakdown ionization carrot-like vertical luminous structure delay }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CummerMar96, author={Cummer, S.A. and Bell, T.F. and Inan, U.S. and Zanetti, L.J.}, title={ VLF remote sensing of the auroral electrojet }, journal={Journal of Geophysical Research}, volume={101}, number={A3}, year={1996}, month={Mar}, pages={5381-9}, abstract={ Investigates a new potential technique to determine the position of the auroral electrojet from ground-based VLF amplitude and phase measurements. The chief advantage of this technique over conventional ground magnetometer measurements is that it can provide data on a continental scale with a small number of receiving stations and with a minimum of data processing. At the edge of the auroral zone, where the electrojet current system flows, high-energy (E>300 keV) precipitating electrons cause local electron density enhancements in the ionosphere which cause phase and amplitude perturbations in VLF waves propagating in the Earth-ionosphere waveguide. Continuous measurements of the amplitude and phase of signals from the Omega North Dakota VLF transmitter were made in Nome, Alaska. Using a two-dimensional model of VLF propagation which accounts for ionospheric disturbances caused by the electron precipitation associated with the electrojet, the amplitude and phase signatures of electrojet incursion across each propagation path were predicted. Seventeen nights of simultaneous VLF amplitude and phase data and ground magnetometer data were examined and catalogued based on the degree of temporal correlation between the two data sets and the degree to which the VLF events matched the propagation simulations. Of the nights exhibiting activity, more than 60% exhibited excellent correlation between the magnetometer and VLF events, and the majority of these showed good agreement with the model results. An additional estimate of the electrojet position was provided for one of the studied sights by field-aligned current measurements from the Freja satellite. A comparison of these independent means of determining the electrojet position shows that they are in good agreement for the night examined }, keywords={ electrojets ionospheric electromagnetic wave propagation ionospheric techniques ionosphere electric current measurement technique ground based method VLF remote sensing auroral electrojet position radiowave amplitude phase Earth-ionosphere waveguide LF propagation electron precipitation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanMar96, author={Inan, U.S. and Slingeland, A. and Pasko, V.P. and Rodriguez, J.V.}, title={ VLF and LF signatures of mesospheric/lower ionospheric response to lightning discharges }, journal={Journal of Geophysical Research}, volume={101}, number={A3}, year={1996}, month={Mar}, pages={5219-38}, abstract={ New evidence is presented of disturbances of the electrical conductivity of the nighttime mesosphere and the lower ionosphere in association with lightning discharges. In addition to extensive documentation of the characteristics of a class of events heretofore referred to as early/fast VLF events, Inan et al. (1993), the present authors data reveal a new feature of these events, consisting of a postonset peak that typically lasts for 1-2 s. They also report the observation of short-duration VLF or LF perturbations, in which the amplitude of the subionospheric signal exhibits a sudden change within 20 ms of the causative lightning discharge, and recovers back to its original level in <3 s. These short-duration events have characteristics similar to the previously observed rapid onset, rapid decay VLF signatures, Doulden et al. (1994). Both the typical and rapidly recovering events are observed primarily when the causative lightning discharge is within +or-50 km of the VLF or LF great circle propagation path, indicating that the scattering from the localized disturbance is highly collimated in the forward direction. The latter in turn implies that for the parameters in hand, the transverse extent of the disturbance must be at least À100-150 km. The measured VLF signatures are compared with the predictions of a three-dimensional model of subionospheric VLF propagation and scattering in the presence of localized ionospheric disturbances produced by electromagnetic impulses and quasi-electrostatic QE fields produced by lightning discharges. The rapidly recovering or short-duration events are consistent with the heating of the ambient electrons by quasi-static electric fields, in cases when heating is not intense enough to exceed-the attachment or ionization thresholds. When no significant electron density changes occur, the conductivity changes due to heating alone last only as long as the QE fields, typically less than a few seconds. When heating is intense enough so t }, keywords={ atmospheric electricity atmospheric electromagnetic wave propagation atmospherics ionospheric disturbances ionospheric electromagnetic wave propagation lightning mesosphere atmospherics radiowave emission thunderstorm VLF signature LF signature mesosphere lower ionosphere response middle atmosphere ionospheric disturbance lightning electric discharge electrical conductivity night postonset peak short-duration perturbation short-duration events radiowave propagation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{AlfordJan96, author={Alford, J. and Engebretson, M. and Arnoldy, R. and Inan, U.}, title={ Frequency variations of quasi-periodic ELF-VLF emissions: a possible new ground-based diagnostic of the outer high-latitude magnetosphere }, journal={Journal of Geophysical Research}, volume={101}, number={A1}, year={1996}, month={Jan}, pages={83-97}, abstract={ Magnetic pulsations and quasi-periodic (QP) amplitude modulations of ELF-VLF waves at Pc 3-4 frequencies (15-50 mHz) are commonly observed simultaneously in cusp-latitude data. The naturally occurring ELF-VLF emissions are believed to be modulated within the magnetosphere by the compressional component of geomagnetic pulsations formed external to the magnetosphere. The authors have examined data from South Pole Station (LÀ14) to determine the occurrence and characteristics of QP emissions. On the basis of 14 months of data during 1987 and 1988 they found that QP emissions typically appeared in both the 0.5-1 kHz and 1-2 kHz receiver channels at South Pole Station and occasionally in the 2-4 kHz channel. The QP emission frequency appeared to depend on solar wind parameters and interplanetary magnetic field (IMF) direction, and the months near fall equinox in both 1987 and 1988 showed a significant increase in the percentage of QP emissions only in the lowest-frequency channel. They present a model consistent with these variations in which high-latitude (nonequatorial) magnetic field minima near the magnetopause play a major role, because the field magnitude governs both the frequency of ELF-VLF emissions and the whistler mode propagation cutoffs. Because the field in these regions will be strongly influenced by solar wind and IMF parameters, variations in the frequency of such emissions may be useful in providing ground-based diagnostics of the outer high-latitude magnetosphere }, keywords={ atmospheric radiation atmospheric techniques magnetosphere micropulsations whistlers atmosphere measurement technique outer magnetosphere magnetic pulsation micropulsation radiowave emission frequency variation quasi-periodic ELF-VLF emission quasiperiodic emissions ELF VLF high-latitude magnetosphere magnetic pulsations amplitude modulation Pc 3 Pc 4 geomagnetic pulsations South Pole Station occurrence characteristics AD 1987 AD 1988 interplanetary magnetic field IMF direction whistler mode propagation cutoff 0.5 to 5 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoFeb96, author={Pasko, V.P. and Inan, U.S. and Bell, T.F.}, title={ Blue jets produced by quasi-electrostatic pre-discharge thundercloud fields }, journal={Geophysical Research Letters}, volume={23}, number={3}, year={1996}, month={Feb}, pages={301-4}, abstract={ Pre-discharge quasi-electrostatic fields immediately above the thundercloud lead to the formation and upward propagation of streamer type ionization channels with features in good agreement with video observations of blue jets }, keywords={ atmospheric electricity electric fields lightning thunderstorms blue jets quasielectrostatic predischarge thundercloud fields upward propagation formation streamer type ionization channels video observations sprites runaway electrons 100 km/s }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Jiunn-Tsair-ChenMar96, author={Jiunn-Tsair Chen and Inan, U.S. and Bell, T.F.}, title={ VLF strip holographic imaging of lightning-associated ionospheric disturbances }, journal={Radio Science}, volume={31}, number={2}, year={1996}, month={Mar}, pages={335-48}, abstract={ A linear array of very low frequency (VLF) receivers, deployed along a line roughly perpendicular to the direction of signal propagation, enables the determination of the size and location of D region disturbances produced by lightning-induced electron precipitation (LEP) bursts or by lightning-induced heating in the vicinity of the great circle VLF propagation paths. The configuration essentially constitutes a strip hologram so that the width of both the amplitude and phase perturbation of the signal pattern recorded along the strip are simply related to the size and location of the disturbance for the range of altitude profiles of disturbed ionization expected for LEP events. The validity of the approach is demonstrated both analytically for single waveguide-mode propagation and also for a realistic propagation path (Annapolis-Stanford) by using a three-dimensional numerical model of VLF propagation and scattering in the Earth-ionosphere waveguide. We also discuss the criteria by which the spacing of discrete elements along the strip can be optimally chosen }, keywords={ array signal processing atmospheric electron precipitation atmospheric temperature D-region Earth-ionosphere waveguide geophysical signal processing holography image processing ionospheric disturbances ionospheric techniques lightning radiowave propagation VLF strip holographic imaging lightning-associated ionospheric disturbances size location D-region disturbances electron precipitation lightning-induced heating great circle VLF propagation paths amplitude and phase perturbation phase perturbation altitude profile disturbed ionization single waveguide-mode propagation Annapolis-Stanford three-dimensional numerical model VLF propagation scattering Earth-ionosphere waveguide discrete elements }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanJan96, author={Inan, U.S. and Sampson, W.A. and Taranenko, Y.N.}, title={ Space-time structure of optical flashes and ionization changes produced by lightning-EMP }, journal={Geophysical Research Letters}, volume={23}, number={2}, year={1996}, month={Jan}, pages={133-6}, abstract={ Intense electromagnetic pulses (EMPs) released by lightning discharges produce bright optical emissions at 80-95 km altitudes emitted in a thin (À30 km) cylindrical shell expanding to radial distances of up to >150 km, lasting for À400 mu s, and appearing in limb-view as a thin layer with À400 km lateral extent }, keywords={ airglow atmospheric ionisation atmospheric optics atmospheric radiation lightning upper atmosphere airglow optical emission thermosphere spatial structure temporal structure optical flash light ionization change lightning EMP electromagnetic pulse EM pulse thin cylindrical shell 80 to 95 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanDec95, author={Inan, U.S. and Bell, T.F. and Pasko, V.P. and Sentman, D.D. and Wescott, E.M. and Lyons, W.A.}, title={ VLF signatures of ionospheric disturbances associated with sprites }, journal={Geophysical Research Letters}, volume={22}, number={24}, year={1995}, month={Dec}, pages={3461-4}, abstract={ VLF perturbations on signals propagating along great-circle-paths (GCP) through electrically active midwest thunderstorms are associated with luminous high altitude glows (referred to as sprites) observed from aircraft or ground. The data constitutes the first evidence that the physical processes leading to sprites also alter the conductivity of the lower ionosphere }, keywords={ airglow ionosphere ionospheric disturbances ionospheric electromagnetic wave propagation lightning mesosphere radiowave propagation thermosphere thunderstorms upper atmosphere ionosphere mesosphere upper atmosphere middle atmosphere VLF signature ionospheric disturbance sprite lightning airglow great-circle-path electrically active midwest thunderstorm United States USA radiowave propagation luminous high altitude glow sprites lower ionosphere electrical conductivity decrease }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JasnaJun94, author={Jasna, D. and Inan, U.S. and Bell, T.F.}, title={ Precipitation of radiation belt electrons by magnetospherically reflected (MR) whistlers }, journal={Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika}, volume={37}, number={6}, year={1994}, month={Jun}, pages={727-40}, abstract={ Uses a test particle simulation model based on gyro-averaged equations of motion to study the influence of oblique magnetospherically reflected (MR) whistlers on the near-loss-cone distribution function of radiation belt electrons. The authors find that MR whistlers originating in lightning can resonantly interact with radiation belt electrons over a broad range of L-shells and precipitate higher energy electrons from lower L-shells. Electrons in the energy range of 1-2.6 Me V are precipitated from L=2, whereas from L=4 the precipitated electron energy range is 150-220 keV. The precipitated differential electron flux due to this interaction is higher for higher L-shells, and the maximum value ranges from Phi /sub E(prec)/(1.11 MeV)=5.2*10/sup -4/ el/cm/sup 2/.s.keV at L=2 to Phi /sub E(prec)/(173 keV)=4.6*10/sup -1/ el/cm/sup 2/.s.keV at L=4. The lifetimes of radiation belt electrons in a given magnetic flux tube around the L-shell on which the interaction takes place are found to be of the order of several days, comparable to lifetimes corresponding to electron loss induced by hiss, which was heretofore assumed to be the dominant loss mechanism. The minimum electron lifetimes vary from 2.47 days for E=1.11 MeV electrons at L=2 to 4.64 days for E=173 keV electrons at L=4 }, keywords={ atmospheric electron precipitation radiation belts whistlers radiation belt electrons magnetospherically reflected whistlers test particle simulation model gyro-averaged equations of motion near-loss-cone distribution function precipitation L-shells precipitated differential electron flux magnetic flux tube electron loss hiss loss mechanism minimum electron lifetimes 1 to 2.6 MeV 150 to 220 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{Lev-TovNov95, author={Lev-Tov, S.J. and Inan, U.S. and Bell, T.F.}, title={ Altitude profiles of localized D region density disturbances produced in lightning-induced electron precipitation events }, journal={Journal of Geophysical Research}, volume={100}, number={A11}, year={1995}, month={Nov}, pages={21375-83}, abstract={ A three-dimensional model of very low frequency (VLF) radio wave propagation in the Earth-ionosphere waveguide in the presence of lower ionospheric disturbances is used to quantitatively interpret VLF signatures of lightning-induced electron precipitation (LEP) events observed in two previously reported cases. One case is that of a 28.5-kHz signal originating in Puerto Rico and propagating to a receiver in Lake Mistissini, Quebec. The other case involves a 24.0-kHz signal originating in Cutler, Maine, and received at Stanford, California. In both cases, high-resolution measurements of the VLF signals were made to accurately document characteristic signatures of LEP events. The comparison of the model calculations with the data yields information about the altitude profiles of electron density of both the extra ionization produced by the LEP events and of the ambient ionospheric D-region. The comparisons are carried out using generally accepted values of the spatial extent of the disturbed regions and the intensity of the particle flux constituting the LEP burst }, keywords={ atmospheric electron precipitation D-region Earth-ionosphere waveguide electron density ionospheric disturbances lightning radiowave propagation ionosphere localized D-region density disturbances lightning-induced electron precipitation events altitude profiles 3D model VLF radio wave propagation Earth-ionosphere waveguide lower ionospheric disturbances high-resolution measurements LEP events electron density ionization disturbed regions particle flux intensity 28.5 kHz 24 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellNov95, author={Bell, T.F. and Inan, U.S. and Danielson, M.T. and Cummer, S.A.}, title={ VLF signatures of ionospheric heating by HIPAS }, journal={Radio Science}, volume={30}, number={6}, year={1995}, month={Nov}, pages={1855-67}, abstract={ The amplitude and phase of subionospherically propagating VLF signals are known to be sensitive indicators of the electron density and temperature at D region altitudes. The authors present new observations at a station in Alaska positioned to provide measurements of VLF signals that have propagated beneath the ionospheric region heated by the high-power auroral stimulation (HIPAS) HF heating facility near Fairbanks, Alaska. Analysis of data from HIPAS campaigns conducted in fall 1992 and spring 1993 has shown that in roughly 60% of the cases analyzed, the amplitude of the 23.4-kHz signal from the NPM transmitter in Hawaii as observed in Fort Yukon, Alaska, exhibited a measurable change in amplitude with the same on/off modulation pattern as that of the HIPAS HF transmissions at 2.85 MHz. In almost 70% of the cases analyzed, the same signal exhibited similar measurable changes in phase. The amplitude changes ranged from -0.2 dB to +0.5 dB, and the sensitivity of the measurement was approximately +or-0.02 dB. The phase changes ranged from -4.5 degrees to -0.3 degrees , and the sensitivity of the measurement was typically +or-0.4 degrees . It is demonstrated that the phase and amplitude changes can be used as diagnostic tools to determine characteristics of the ambient electron density profile above the HIPAS facility }, keywords={ D-region electron density ionospheric disturbances ionospheric electromagnetic wave propagation radiowave propagation ionospheric heating VLF signatures amplitude phase subionospherically propagating VLF signals electron density temperature D region HIPAS high-power auroral stimulation HF heating facility on/off modulation pattern AD 1992 to 1993 23.4 kHz 2.85 MHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellAug95, author={Bell, T.F. and Pasko, V.P. and Inan, U.S.}, title={ Runaway electrons as a source of red sprites in the mesosphere }, journal={Geophysical Research Letters}, volume={22}, number={16}, year={1995}, month={Aug}, pages={2127-30}, abstract={ Large quasi-electrostatic (QE) fields above thunderclouds produce an upward traveling beam of approximately 1 MeV runaway electrons which may contribute to the production of optical emissions above thunderclouds referred to as red sprites. Results of a one dimensional computer simulation model suggest that the runaway electrons can produce optical emissions similar in intensity and spectra to those observed in red sprites, but only for large QE fields produced by positive cloud-to-ground discharges lowering 250 C or more to ground from an altitude of at least 10 km. Differences in predicted optical spectra from that of other mechanisms suggest that the runaway electron mechanism can be readily tested by high resolution spectral measurements of red sprites }, keywords={ atmospheric electricity electric fields electron beam effects mesosphere thunderstorms source red sprites mesosphere quasielectrostatic fields thunderclouds upward travelling electron beam optical emissions 1D computer simulation model emission intensity upward discharges positive cloud-to-ground discharges predicted optical spectra runaway electron mechanism 20 keV to 20 MeV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarMay95, author={Sonwalkar, V.S. and Inan, U.S. and Aggson, T.L. and Farrell, W.M. and Pfaff, R.}, title={ Focusing of nonducted whistlers by the equatorial anomaly }, journal={Journal of Geophysical Research}, volume={100}, number={A5}, year={1995}, month={May}, pages={7783-90}, abstract={ Impulsive ELF/VLF electric field bursts observed by the vector electric field instrument (VEFI) on the Dynamics Explorer 2 (DE 2) satellite on almost every crossing of the geomagnetic equator in the evening hours are interpreted as originating in lightning discharges. These signals that peak in intensity near the magnetic equator are observed within 5-20 degrees latitude of the geomagnetic equator at altitudes of 300-500 km with amplitudes of the order of approximately mV/m in the 512- to 1024-Hz frequency band of the VEFI instrument. Whistler-mode ELF/VLF wave propagation through a horizontally stratified ionosphere predicts strong attenuation of subionospheric signals reaching the equator at low altitudes. However, ray tracing analysis shows that the presence of the equatorial density anomaly, commonly observed in the upper ionosphere during evening hours, leads to the focusing of the wave energy from lightning near the geomagnetic equator at low altitudes, thus accounting for all observed aspects of the phenomenon. The observations presented indicate that during certain hours in the evening, almost all the energy input from lightning discharges entering the ionosphere at <30 degrees latitude remains confined to a small region (in altitude and latitude) near the geomagnetic equator. The net wideband electric field, extrapolated from the observed electric field values in the 512- to 1024-Hz band, can be approximately 10 mV/m or higher. These strong electric fields generated in the ionosphere by lightning at local evening times may be important for the equatorial electrodynamics of the ionosphere }, keywords={ F-region ionospheric electromagnetic wave propagation whistlers radiowave propagation nonducted whistlers whistler focusing ionosphere equatorial electrodynamics equatorial anomaly impulsive ELF electric field burst VLF lightning F-region horizontally stratified ionosphere strong attenuation 300 to 500 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PaskoFeb95, author={Pasko, V.P. and Inan, U.S. and Taranenko, Y.N. and Bell, T.F.}, title={ Heating, ionization and upward discharges in the mesosphere due to intense quasi-electrostatic thundercloud fields }, journal={Geophysical Research Letters}, volume={22}, number={4}, year={1995}, month={Feb}, pages={365-8}, abstract={ Quasi-electrostatic fields that temporarily exist at high altitudes following the sudden removal (e.g. by a lightning discharge) of thundercloud charge at low altitudes are found to significantly heat mesospheric electrons and produce ionization and light. The intensity, spatial extent, duration and spectra of optical emissions produced are consistent with the observed features of the red sprite type of upward discharges }, keywords={ atmospheric ionisation electrons electrostatic discharge mesosphere plasma heating thunderstorms mesospheric electron heating ionization upward discharges mesosphere intense quasielectrostatic thundercloud fields lightning discharge sudden thundercloud charge removal light production ionization production intensity spatial extent duration spectra optical emissions red sprites }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarFeb95, author={Sonwalkar, V.S. and Inan, U.S. and Bell, T.F.}, title={ An interpretation of a mysterious 3.0- to 4.6-kHz emission band observed on Voyager 2 near Neptune }, journal={Journal of Geophysical Research}, volume={100}, number={A2}, year={1995}, month={Feb}, pages={1795-809}, abstract={ A whistler mode interpretation is provided for the narrowband signal (f approximately 3-4.6 kHz, Delta f approximately 200-800 Hz) detected by the plasma wave instrument on Voyager 2 during its encounter with Neptune. The analysis indicates that this signal may have been generated in a limited spatial region and that it propagated to other regions of the Neptunian magnetosphere in the nonducted whistler mode with wave normal vectors lying close to the whistler mode resonance cone. The observed frequency variation of the emission along the Voyager 2 trajectory is consistent with this interpretation. The source location is estimated to be near the magnetic equator at L approximately 4 and dipole longitude of 111 degrees W (260 degrees W longitude in Neptune coordinate system). The source frequency and bandwidth are estimated to be 3.6 kHz and 300 Hz, respectively. The waves most likely would have been generated by energetic electrons with 2- to 20-keV parallel energy via a gyroresonance mechanism. The interpretation of the narrowband emissions places the following limits on the Neptunian thermal plasma density and temperature: (1) N/sub e,min/>0.16 el/cm/sup 3/ for 1.2R/sub N/770 km distance between NAA and the NAU-Gander great circle path. Heating by the NSS (21.4 kHz, 265 kW) and NLK (24.8 kHz, 850 kW) transmitters was observed serendipitously in data from earlier measurements of the amplitudes of VLF signals propagating in the Earth-ionosphere waveguide. A three-dimensional model of wave absorption and electron heating in a magnetized, weakly ionized plasma is used to calculate the extent and shape of the collision frequency (i.e. electron temperature) enhancement above a VLF transmitter. The calculated changes in the D-region conductivity are used in a three-dimensional model of propagation in the Earth-ionosphere waveguide to predict the effect of the heated patch on a subionospheric VLF probe wave }, keywords={ D-region Earth-ionosphere waveguide ionospheric disturbances plasma radiofrequency heating radiowave propagation heated nighttime D-region Earth-ionosphere waveguide VLF signals ionospheric cooling ionospheric heating NAA transmitter NSS probe wave NAU probe wave NSS transmitter NLK transmitter 3D propagation model wave absorption electron heating magnetized weakly ionized plasma collision frequency electron temperature enhancement D-region conductivity subionospheric VLF probe wave 24 kHz 21.4 kHz 28.5 kHz 24.8 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellApr94, author={Bell, T.F. and Inan, U.S. and Lauben, D. and Sonwalkar, V.S. and Helliwell, R.A. and Sobolev, Ya.P. and Chmyrev, V.M. and Gonzalez, S.}, title={ DE-1 and COSMOS 1809 observations of lower hybrid waves excited by VLF whistler mode waves }, journal={Geophysical Research Letters}, volume={21}, number={8}, year={1994}, month={Apr}, pages={653-6}, abstract={ Past work demonstrates that strong lower hybrid (LH) waves can be excited by electromagnetic whistler mode waves throughout large regions of the topside ionosphere and magnetosphere. The effects of the excited LH waves upon the suprathermal ion population in the topside ionosphere and magnetosphere depend upon the distribution of LH wave amplitude with wavelength lambda . The present work reports plasma wave data from the DE-1 and COSMOS 1809 spacecraft which suggests that the excited LH wave spectrum has components for which lambda or=6 eV energy range can be heated by 20 to 40 eV as a result of a single lightning discharge. They also show how the number density of >or=6 eV H/sup +/ ions is enhanced by preheating resulting from the absorption of proton whistlers in the 500-1000 km altitude range. For lightning discharge rates of one or more per second over a 10/sup 4/ km/sup 2/ area, the authors' model predicts a total energy gain for the H/sup +/ ions of 400 eV to 2 KeV and a perpendicular ion flux of j/sub perpendicular to / approximately 10/sup 5/ to 10/sup 6/ cm/sup -2/ sec/sup -1/. These fluxes should be observable on low altitude spacecraft using presently available instrumentation }, keywords={ ionosphere ionospheric electromagnetic wave propagation thunderstorms whistlers ion heating lower atmosphere meteorology plasma wave radiowave suprathermal ions thunderstorm cells topside ionosphere lower hybrid waves linear mode coupling intense electromagnetic whistler mode radiation lightning field-aligned plasma density irregularities H/sup +/ whistlers 500 to 1000 km H }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{TaranenkoAug93, author={Taranenko, Y.N. and Inan, U.S. and Bell, T.F.}, title={ Interaction with the lower ionosphere of electromagnetic pulses from lightning: heating, attachment, and ionization }, journal={Geophysical Research Letters}, volume={20}, number={15}, year={1993}, month={Aug}, pages={1539-42}, abstract={ A Boltzmann formulation of the electron distribution function and Maxwell's equations for the electromagnetic (EM) fields are used to simulate the interaction of lightning radiated EM pulses with the lower ionosphere. Ionization and dissociative attachment induced by the heated electrons cause significant changes in the local electron density (N/sub e/). Due to 'slow' field changes of typical lightning EM pulses over time scales of tens of mu s, the distribution function follows the quasi-equilibrium solution of the Boltzmann equation in the altitude range of interest (70 to 100 km). The EM pulse is simulated as a planar 100 mu s-long single period oscillation of a 10-kHz wave injected at 70 km. Under nighttime conditions, individual pulses of intensity 10-20 V/m (normalized to 100 km horizontal distance) produce changes in N/sub e/ of 1-30% while a sequence of pulses leads to strong modification of N/sub e/ at altitudes <95 km. The N/sub e/ changes produce a 'sharpening' of the lower ionospheric boundary by causing a reduction in electron density at 75-85 km (due to attachment) and a substantial increase at 85-95 km (due to ionization) (e.g. the scale height decreases by a factor of approximately 2 at approximately 85 km for a single 20 V/m EM pulse). No substantial N/sub e/ changes occur during daytime }, keywords={ atmospheric ionisation electromagnetic pulse electron attachment ionospheric electromagnetic wave propagation lightning plasma heating lower ionosphere lightning radiated EM pulses heating VLF perturbations ionization Boltzmann equation Maxwell equations dissociative attachment heated electrons local electron density oscillation nighttime conditions modification 70 to 100 km 100 mus 10 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Inan93, author={Inan, U.S. and Rodriguez, J.V.}, title={ Lightning-induced effects on VLF/LF radio propagation }, booktitle={ELF/VLF/LF Radio Propagation and Systems Aspects (AGARD-CP-529)}, volume={}, number={}, year={1993}, month={}, pages={9/10 pp.}, abstract={ At least two different ways in which energy from lightning discharges couples into the lower ionosphere and the radiation belts have come to the fore. This paper briefly reviews these results especially from the point of view of their effects on VLF/LF radio propagation in the earth-ionosphere waveguide. Lightning-induced electron precipitation, and lightning-induced heating and ionization of the lower ionosphere are discussed. A planned active VLF wave-injection experiment is designed to investigate ionospheric heating by VLF waves under controlled conditions and to generate ELF waves by modulated VLF heating }, keywords={ atmospheric electron precipitation atmospheric ionisation ionospheric electromagnetic wave propagation lightning radiation belts radiowave propagation lightning-induced electron precipitation lower ionosphere radiation belts VLF/LF radio propagation earth-ionosphere waveguide lightning-induced heating ionospheric heating modulated VLF heating }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PoulsenSep93, author={Poulsen, W.L. and Bell, T.F. and Inan, U.S.}, title={ The scattering of VLF waves by localized ionospheric disturbances produced by lightning-induced electron precipitation }, journal={Journal of Geophysical Research}, volume={98}, number={A9}, year={1993}, month={Sep}, pages={15553-9}, abstract={ A 3D model of the scattering of VLF waves in the Earth-ionosphere waveguide by localized disturbances in the lower ionosphere is examined for typical disturbances expected to be produced by lightning-induced electron precipitation events. Results indicate that the scattering is generally independent of the conductivity and permittivity of the Earth's surface immediately beneath the disturbed region except for extremely low conductivities such as that found over deep ice caps. Thus the scattered signal is principally a function of the ionospheric perturbation. For typical disturbances characterized by altitude profiles of enhanced ionization expected for 1.4or=5.0. ELF/VLF noise measured near the epicenters was analyzed for occurrence rates and average spectra, as well as for peak and mean electric field intensities in three spectrometers covering a frequency range of 4 Hz-512 kHz in 20 channels }, keywords={ atmospheric radiation earthquakes ionosphere ionospheric electromagnetic wave propagation magnetosphere terrestrial electricity ELF VLF radiowave emission earthquake induced EM wave geoelectric precursor AD 1983 magnetosphere AD 1981 AD 1982 ionosphere DE 2 0.3 to 512 kHz 4 to 300 Hz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PoulsenFeb93, author={Poulsen, W.L. and Inan, U.S. and Bell, T.F.}, title={ A multiple-mode three-dimensional model of VLF propagation in the Earth-ionosphere waveguide in the presence of localized D region disturbances }, journal={Journal of Geophysical Research}, volume={98}, number={A2}, year={1993}, month={Feb}, pages={1705-17}, abstract={ Transient localized D region disturbances, such as those associated with lightning discharges, affect the characteristics of VLF waves propagating in the Earth-ionosphere waveguide. In particular, both phase and amplitude changes in the subionospheric signal can be observed at receiving sites as a result of the wave scattering that takes place in the disturbed region. The authors present a multiple-mode three-dimensional model of VLF propagation in the Earth-ionosphere waveguide in the presence of localized D region disturbances. This new model is applied to experimental observations and is found to be in general agreement. The diagnostics potential of the model for characterizing energetic particle precipitation events is discussed }, keywords={ atmospheric elementary particle precipitation D-region ionospheric electromagnetic wave propagation radiowave propagation D-region radiowave propagation multiple-mode three-dimensional model VLF propagation Earth-ionosphere waveguide VLF waves phase amplitude subionospheric signal energetic particle precipitation events }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanOct92, author={Inan, U.S. and Rodriguez, J.V. and Lev-Tov, S. and Oh, J.}, title={ Ionospheric modification with a VLF transmitter }, journal={Geophysical Research Letters}, volume={19}, number={20}, year={1992}, month={Oct}, pages={2071-4}, abstract={ Detectable heating of the nighttime D-region by a 28.5 kHz signal is observed in 16 out of 144 cases with events occurring under conditions of moderate to low D-region electron densities as represented by the unperturbed VLF signal levels. Three dimensional modeling of the effects of NAU heating on a probe VLF signal predicts values in general agreement with observations and suggests that maximum effects should occur under tenuous D-region conditions }, keywords={ D-region ionospheric electromagnetic wave propagation plasma radiofrequency heating night radiowave heating D-region ionosphere modification three-dimensional model AD 1989 VLF transmitter nighttime modeling 28.5 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{RodriguezOct92, author={Rodriguez, J.V. and Inan, U.S. and Bell, T.F.}, title={ D region disturbances caused by electromagnetic pulses from lightning }, journal={Geophysical Research Letters}, volume={19}, number={20}, year={1992}, month={Oct}, pages={2067-70}, abstract={ Electromagnetic pulses from weak lightning discharges (E/sub 100/=1 V/m, where E/sub 100/ is the field strength in the radiation pattern maximum at 100 km) may substantially heat D region electrons, while only pulses with E/sub 100/>or=20 V/m may create electron density enhancements >or=10% of ambient. A E/sub 100/=20 V/m pulse from a horizontal radiator at 5 km altitude (e.g. the cloud discharge at the stepped-leader onset) increases the electron temperature by a factor of approximately 400 maximum and the electron density (in one ionization cycle) by approximately 230 cm/sup 3/ maximum; the widths at half-maximum of the heated and ionized regions are 200 km and 90 km. A E/sub 100/=40 V/m pulse from a vertical radiator at 0 km altitude (e.g. the vertical return stroke channel) increases the electron temperature by a factor of approximately 350 maximum and the electron density by approximately 80 cm/sup 3/ maximum }, keywords={ D-region lightning electron heating modification EM pulse EM radiation disturbance radiowave emission D-region ionosphere electromagnetic pulses lightning electron temperature }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{TaranenkoSep92, author={Taranenko, Y.N. and Inan, U.S. and Bell, T.F.}, title={ Optical signatures of lightning-induced heating of the D region }, journal={Geophysical Research Letters}, volume={19}, number={18}, year={1992}, month={Sep}, pages={1815-18}, abstract={ Lightning-induced heating of the nighttime D region leads to the excitation of a number of lines of O, O/sub 2/, N/sub 2/, O/sub 2//sup +/, and N/sub 2//sup +/, at intensities of 10-10/sup 9/ rayleighs (R) for vertical observations. For example, the 5577 AA emission from O has intensity approximately 60 R lasting for approximately 350 ms while the 1st and 2nd positive bands of N/sub 2/ are at approximately 10/sup 9/ R but last only approximately 50 mu s }, keywords={ airglow D-region lightning plasma heating visible D-region ionosphere airglow lightning-induced heating O O/sub 2/ N/sub 2/ O/sub 2//sup +/ N/sub 2//sup +/ }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GlukhovNov92, author={Glukhov, V.S. and Pasko, V.P. and Inan, U.S.}, title={ Relaxation of transient lower ionospheric disturbances caused by lightning-whistler-induced electron precipitation bursts }, journal={Journal of Geophysical Research}, volume={97}, number={A11}, year={1992}, month={Nov}, pages={16971-9}, abstract={ A quantitative model of the relaxation of transient lower ionospheric (D-region) disturbances caused by lightning-induced electron precipitation is developed, taking advantage of known particular features of the lightning-induced disturbances, such as the fact that they are produced in typically <1 s and decay over 10-100 s. The model represents the nighttime D-region as consisting of only four kinds of charged particles (electrons, positive ions, negative ions, and positive cluster ions) and is particularly suited for description of the detailed behavior of the electron density. Application of the model to some previously modeled disturbances indicates that some of the least known chemical reaction rates in the nighttime D-region altitudes may be measurable using subionospheric VLF data }, keywords={ atmospheric electron precipitation D-region ionosphere lightning D-region transient lower ionospheric disturbances lightning-whistler-induced electron precipitation bursts quantitative model relaxation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JasnaAug92, author={Jasna, D. and Inan, U.S. and Bell, T.F.}, title={ Precipitation of suprathermal (100 eV) electrons by oblique whistler waves }, journal={Geophysical Research Letters}, volume={19}, number={16}, year={1992}, month={Aug}, pages={1639-42}, abstract={ Electron precipitation induced by oblique whistler waves is investigated using a new test particle simulation code based on gyro-averaged equations of motion. The results indicate that highly oblique waves can efficiently pitch angle scatter suprathermal electrons (10-100 eV). At L=3, for example, in a single encounter with a wave with power density S approximately 8 pW/m/sup 2/ propagating at psi =60 degrees with respect to the Earth's magnetic field B/sub 0/, the average pitch angle scattering of 100 eV electrons is approximately 0.1 degrees . In comparison, the average scattering of energetic (100 keV) electrons by a parallel propagating wave with the same S is approximately 0.01 degrees . Estimates indicate that the precipitated electron energy fluxes resulting from the interaction of approximately 100 eV electrons with oblique waves can be up to 30 times larger than that due to the precipitation of 100 keV electrons by parallel propagating waves }, keywords={ atmospheric electron precipitation magnetosphere magnetospheric electromagnetic wave propagation plasma radiation belts whistlers radiation belt electrons VLF magnetosphere suprathermal electrons precipitation wave-particle interactions wave propagation direction whistler wave power density oblique whistler waves test particle simulation code gyro-averaged equations of motion highly oblique waves average pitch angle scattering precipitated electron energy fluxes 100 eV 10 to 25 kHz 5.60 to 15.79 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{ImhofSep92, author={Imhof, W.L. and Voss, H.D. and Mobilia, J. and Datlowe, D.W. and Gaines, E.E. and McGlennon, J.P. and Inan, U.S.}, title={ Relativistic electron microbursts }, journal={Journal of Geophysical Research}, volume={97}, number={A9}, year={1992}, month={Sep}, pages={13829-37}, abstract={ The authors report the first satellite observations of relativistic (>1 MeV) electron precipitation in microbursts with measured durations of less than 1 s. The data on these relativistic microbursts appear to indicate that many of the bursts may be due to wave-particle interaction not with whistler mode chorus but possibly with other waveforms. The locations of many of the relativistic microbursts are concentrated at the outer edge of the trapped radiation belt, where the gyroradii of the electrons are comparable to the curvature of the magnetic field lines and stable trapping may therefore not occur. The preferred location of the microbursts, which may be primarily spatial in character, implies the possible importance of irregularities in the magnetic field lines near the trapping boundary as the responsible mechanism }, keywords={ atmospheric electron precipitation radiation belts magnetosphere atmosphere electron microbursts relativistic microbursts wave-particle interaction trapped radiation belt gyroradii 1 MeV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr92, author={Inan, U.S. and Chiu, Y.T. and Davidson, G.T.}, title={ Whistler-mode chorus and morningside aurorae }, journal={Geophysical Research Letters}, volume={19}, number={7}, year={1992}, month={Apr}, pages={653-6}, abstract={ Quasi-electrostatic ELF/VLF chorus emissions immediately above the equatorial half-gyrofrequency, observed to propagate with wave normal angle ( psi ) within 0.4-1.2 degrees of the resonance cone ( psi /sub r/) (Muto et al., 1987), are shown to efficiently resonate with 0.1-10 keV electrons. These waves may thus be important in driving the relatively low energy (<10 keV) component of pulsating aurorae and the morning-side diffuse aurorae ( approximately 1 keV) }, keywords={ atmospheric electron precipitation aurora magnetospheric electromagnetic wave propagation radiowave propagation whistlers whistler mode chorus electron precipitation quasielectrostatic ELF-VLF chorus emission radiowaves magnetosphere morningside aurorae pulsating aurorae diffuse aurorae 0.1 to 10 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{DraganovFeb92, author={Draganov, A.B. and Inan, U.S. and Sonwalkar, V.S. and Bell, T.F.}, title={ Magnetospherically reflected whistlers as a source of plasmaspheric hiss }, journal={Geophysical Research Letters}, volume={19}, number={3}, year={1992}, month={Feb}, pages={233-6}, abstract={ Ray-tracing simulations and estimates of whistler wave damping show that magnetospherically reflected whistlers can persist for approximately 10/sup 2/ s in a low frequency band (f approximately 1 kHz). The combined contribution from whistler rays produced by a single lightning flash but entering the magnetosphere at different points form a continuous hiss-like signal, as observed at a fixed point. Estimates indicate that the total whistler wave energy input into the magnetosphere from lightning discharges may maintain experimentally observed levels of magnetospheric hiss }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation whistlers magnetosphere plasmasphere radiowave emission ELF whistler reflection reflected whistlers hiss whistler wave damping lightning magnetosphere 1 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{MielkeJan92, author={Mielke, T.A. and Elkins, C.J. and Helliwell, R.A. and Inan, U.S.}, title={ Excitation of whistler mode signals via injection of polarized VLF waves with the Siple transmitter }, journal={Radio Science}, volume={27}, number={1}, year={1992}, month={Jan}, pages={31-46}, abstract={ Whistler mode waves (2-4 kHz) of various polarizations were transmitted by the Siple Station, Antarctica, VLF transmitter and received near the geomagnetic conjugate point at Lake Mistissini, Quebec. Excitation of a multiplicity of magnetospheric propagation paths and the received signal strength were observed to depend on the transmitter antenna polarization. Where whistler mode growth and emission triggering occurred, saturated peak values of received signals were independent of antenna polarization and initial injected power levels. Propagation paths of ducted Siple signals observed at Lake Mistissini were identified with propagation paths deduced from natural whistlers, from which the L shell values and equatorial number densities for the paths were calculated. The observations are discussed in the context of a simplified model of the coupling from the Siple antenna into the ionosphere, which provides reasonable agreement with observations }, keywords={ magnetospheric electromagnetic wave propagation radiowave propagation whistlers VLF ELF radiowaves ducted signals whistler mode signals polarized VLF waves Siple transmitter magnetospheric propagation paths received signal strength transmitter antenna polarization growth emission triggering injected power levels L shell values equatorial number densities ionosphere 2 to 4 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{TaranenkoJan92, author={Taranenko, Y.N. and Inan, U.S. and Bell, T.F.}, title={ VLF-HF heating of the lower ionosphere and ELF wave generation }, journal={Geophysical Research Letters}, volume={19}, number={1}, year={1992}, month={Jan}, pages={61-4}, abstract={ For incident wave power densities of 10/sup -6/-10/sup -2/ W/m/sup 2/ (at 30 km altitude), VLF heating of the D-region (<90 km) is found to be 2-10 times more effective (depending on power) than HF heating, resulting in comparable perturbations of subionospheric VLF probe waves in spite of up to 10/sup 3/ times larger power density utilized in HF heating and at least as efficient in ELF wave generation. In view of generally larger (100*100 km) areas of the ionosphere illuminated by VLF transmitters, ELF wave generation by modulated VLF heating is estimated to produce ELF power levels of approximately 100 mW, comparable with or larger than those produced in typical HF heating experiments. ELF wave generation in a typical midlatitude ambient ionosphere occurs primarily via the modulation of Pedersen current whereas in a typical auroral ionosphere Hall current is dominant for pump wave frequencies up to approximately 6 MHz. For 10-30 MHz and power densities >10/sup -4/ W/m/sup 2/, Pedersen current modulation is again dominant, potentially providing up to 2-15 times higher ELF dipole moment than those found in experiments using 3-5 MHz heaters }, keywords={ ionospheric electromagnetic wave propagation plasma radiofrequency heating radiowave propagation radiowave absorption lower ionosphere ELF wave generation power densities VLF heating D-region HF heating perturbations heating experiments Pedersen current auroral ionosphere Hall current pump wave frequencies modulation dipole moment 30 to 150 km }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{RodriguezJan92, author={Rodriguez, J.V. and Inan, U.S. and Li, Y.Q. and Holzworth, R.H. and Smith, A.J. and Orville, R.E. and Rosenberg, T.J.}, title={ A case study of lightning, whistlers, and associated ionospheric effects during a substorm particle injection event }, journal={Journal of Geophysical Research}, volume={97}, number={A1}, year={1992}, month={Jan}, pages={65-75}, abstract={ Simultaneous ground-based observations of narrowband and broadband VLF radio waves and of cloud-to-ground lightning were made at widely spaced locations during the 1987 Wave-Induced Particle Precipitation (WIPP) campaign, conducted from Wallops Island, Virginia. Based on these observations, the first case study has been made of the relationships among located cloud-to-ground (CG) lightning flashes, whistlers, and associated ionospheric effects during a substorm particle injection event. This event took place two days after the strongest geomagnetic storm of 1987, during a reintensification in geomagnetic activity (Kp=5) that did not affect the high rate of whistlers observed at Faraday Station, Antarctica (L=2.46). At the time of the injection event, several intense nighttime thunderstorms were located over Long Island and the coast of New England, between 400 km northwest and 600 km north of the region geomagnetically conjugate to Faraday }, keywords={ atmospherics lightning magnetic storms whistlers cloud to ground flashes atmospherics United States lightning whistlers ionospheric effects substorm particle injection event VLF radio waves geomagnetic storm geomagnetic activity intense nighttime thunderstorms Long Island New England }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr91, author={Inan, U.S. and Bell, T.F. and Rodriguez, J.V.}, title={ Heating and ionization of the lower ionosphere by lightning }, journal={Geophysical Research Letters}, volume={18}, number={4}, year={1991}, month={Apr}, pages={705-8}, abstract={ Nighttime ionospheric electrons at 90-95 km altitude are heated by a factor of 100-500 during the upward passage of short (<100 mu s) pulses of intense (5-20 V/m at 100 km distance) electromagnetic radiation from lightning. Heated electrons with average energy of 4-20 eV in turn produce secondary ionization, of up to 400 cm/sup -3/ at approximately 95 km altitude in a single ionization cycle ( approximately 3 mu s). With the time constant of heating being 5-10 mu s, a number of such ionization cycles can occur during a 50 mu s radiation pulse, leading to even higher density enhancements. This effect can account for observations of 'early' or 'fast' subionospheric VLF perturbations }, keywords={ atmospheric ionisation atmospheric radiation atmospheric temperature atmospheric thermodynamics D-region electron density ionosphere ionospheric electromagnetic wave propagation lightning nighttime ionospheric electrons heating aeronomy short intense EM radiation pulses ionosphere ionisation D-region ionisation hot electrons energy ionisation cycle time EM pulse duration ionosphere heating time constant fast VLF perturbations ionisation bubbles lower ionosphere lightning secondary ionization single ionization cycle density enhancements subionospheric VLF perturbations 90 to 95 km 3000 ns 100 km 5 to 10 mus 50 mus 4 to 20 eV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{DraganovJun91, author={Draganov, A.B. and Inan, U.S. and Taranenko, Y.N.}, title={ ULF magnetic signatures at the Earth surface due to ground water flow: a possible precursor to earthquakes }, journal={Geophysical Research Letters}, volume={18}, number={6}, year={1991}, month={Jun}, pages={1127-30}, abstract={ Magnetic field fluctuations at the Earth's surface of Delta B/B approximately 10/sup -5/ at <1 Hz are shown to result from motion with a peak velocity of approximately 4 cm/s of ground water ( approximately 4 S/m) at approximately 5 km depth. Surface field changes can occur due to either divergence free fluid motion with transverse spatial wavelengths of a few tens of km, and/or homogeneous flow which displaces local inhomogeneities in the Earth magnetic field }, keywords={ earthquakes groundwater seismology terrestrial electricity earthquake seismology groundwater magnetic field fluctuation ULF magnetic signatures Earth surface ground water flow precursor divergence free fluid motion 0.01 to 0.5 Hz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellMar91, author={Bell, T.F. and Inan, U.S. and Sonwalkar, V.S. and Helliwell, R.A.}, title={ DE-1 observations of lower hybrid waves excited by VLF whistler mode waves }, journal={Geophysical Research Letters}, volume={18}, number={3}, year={1991}, month={Mar}, pages={393-6}, abstract={ Recent satellite data show high amplitude lower hybrid (LH) waves excited by electromagnetic (EM) whistler mode waves throughout magnetospheric regions where small scale magnetic-field-aligned plasma density irregularities exist. One important consequence in the auroral acceleration region is the heating of suprathermal ions by the excited LH waves. To evaluate such heating it is necessary to know the wavelength ( lambda ) range of the waves, information not previously available since most past observations were made with long (l>or=75; l=antenna length) electric dipole antennas which have very poor response for lambda 40 keV electrons in association with ducted whistlers may thus be accompanied by substantial fluxes of lower energy (10 eV-40 keV) electrons precipitated by the nonducted components }, keywords={ atmospheric electron precipitation magnetosphere radiation belts EM wave radiowave electron precipitation radiation belt loss process magnetosphere wave particle interaction first order cyclotron energetic particles oblique whistler waves Landau resonant pitch angle scattering }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{WolfDec90, author={Wolf, T.G. and Inan, U.S.}, title={ Path-dependent properties of subionospheric VLF amplitude and phase perturbations associated with lightning }, journal={Journal of Geophysical Research}, volume={95}, number={A12}, year={1990}, month={Dec}, pages={20997-10015}, abstract={ A comprehensive study of lightning-associated amplitude and phase perturbations on multiple VLF/LF signals (Trimpi events) observed at Stanford, California and at Palmer Station, Antarctica, has revealed a number of new properties that appear to be characteristic of the particular signal paths. None of the existing models of the Trimpi effect are found to explain all of the observed new features. Instead, the new experimental findings provide an empirical framework to guide the evaluation of more sophisticated models }, keywords={ ionospheric electromagnetic wave propagation lightning radiowave propagation subionospheric amplitude perturbations phase perturbations lightning multiple VLF/LF signals Trimpi events }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JasnaOct90, author={Jasna, D. and Inan, U.S. and Bell, T.F.}, title={ Equatorial gyroresonance between electrons and magnetospherically reflected whistlers }, journal={Geophysical Research Letters}, volume={17}, number={11}, year={1990}, month={Oct}, pages={1865-8}, abstract={ Magnetospherically reflected whistlers resonantly interact with energetic (of order 100 keV) electrons in a relatively narrow energy range during multiple equatorial crossings over a wide range of L-shells (1.54 over a approximately 40 degrees range of latitudes including the geomagnetic equator and are often accompanied by discrete emissions or a band of hiss. Some observed features are consistent with previous observations of electrostatic plasma waves (Ondoh et al., 1989; Reinleitner et al., 1983); however, the magnetic measurements clearly indicate that the impulsive signals are electromagnetic in nature. The possibility of spacecraft discharge effects as the cause of these signals is discussed }, keywords={ artificial satellites atmospheric radiation magnetosphere AD 1985 01 to 1989 12 magnetosphere wideband VLF EM bursts Dynamics Explorer 1 DE 1 satellite discrete emissions hiss impulsive signals spacecraft discharge effects 0.650 to 16.0 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanOct90, author={Inan, U.S. and Knifsend, F.A. and Oh, J.}, title={ Subionospheric VLF 'imaging' of lightening-induced electron precipitation from the magnetosphere }, journal={Journal of Geophysical Research}, volume={95}, number={A10}, year={1990}, month={Oct}, pages={17217-31}, abstract={ High-resolution measurements of subionospheric VLF signals at multiple sites are used as a new tool to assess the spatial distribution and occurrence of ionospheric disturbances associated with lightning-induced electron precipitation. Simultaneous observations in California, Saskatchewan and Quebec of VLF signals from multiple sources allow the monitoring of event activity over a coarse grid covering the continental United States. Association of the observed VLF signal perturbations with lightning is often made on the basis of time correlation with prominent radio atmospherics. Simultaneous observations of individual events on subionospheric paths that 'cross' one another are used to locate the disturbed ionospheric region(s). Absence of perturbations on nearby paths permits assessment of the spatial extent of the region with a varying degree of accuracy, depending on the distribution of signal paths }, keywords={ atmospheric electron precipitation ionosphere magnetosphere subionospheric imaging lightening-induced electron precipitation magnetosphere spatial distribution occurrence ionospheric disturbances California Saskatchewan Quebec United States }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GailSep90, author={Gail, W.B. and Inan, U.S. and Helliwell, R.A. and Carpenter, D.L.}, title={ Gyroresonant wave-particle interactions in a dynamic magnetosphere }, journal={Journal of Geophysical Research}, volume={95}, number={A9}, year={1990}, month={Sep}, pages={15103-12}, abstract={ Experimental and theoretical methods for studying gyroresonant wave-particle interactions (WPI) in the magnetosphere commonly assume that the magnetic field is static over the time scales of interest. In order to investigate the effect of nonequilibrium or dynamic magnetospheric processes in WPI, the response of the interaction mechanism to time-dependent perturbations in the magnetic field was examined using the global field compressions that occur during sudden commencements (sc). By measuring modifications of the wave spectrum and electron distribution during sc, the response of the WPI mechanism to slow variations in the magnetic field and plasma environment can be determined. This technique was used to examine the applicability of both nonlinear and quasi-linear descriptions of gyroresonant WPI to dynamic environments }, keywords={ magnetosphere plasma nonequilibrium processes atmosphere dynamic magnetosphere gyroresonant wave-particle interactions magnetic field time-dependent perturbations global field compressions sudden commencements wave spectrum electron distribution plasma quasi-linear descriptions }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CarlsonSep90, author={Carlson, C.R. and Helliwell, R.A. and Inan, U.S.}, title={ Space-time evolution of whistler mode wave growth in the magnetosphere }, journal={Journal of Geophysical Research}, volume={95}, number={A9}, year={1990}, month={Sep}, pages={15073-89}, abstract={ A new model is developed to simulate the space-time evolution of a propagating coherent whistler mode wave pulse in the magnetosphere. The model is applied to the case of single frequency (2-6 kHz) wave pulses injected into the magnetosphere near L approximately=4, using the VLF transmitting facility at Siple Station, Antarctica. The mechanism for growth is cyclotron resonance between the circularly polarized waves and the gyrating energetic electrons of the radiation belts }, keywords={ magnetospheric electromagnetic wave propagation radiowave propagation whistlers whistler mode wave growth magnetosphere space-time evolution VLF cyclotron resonance radiation belts 2 to 6 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{JamesAug90, author={James, H.G. and Inan, U.S. and Rietveld, M.T.}, title={ Observations on the DE 1 spacecraft of ELF/VLF waves generated by an ionospheric heater }, journal={Journal of Geophysical Research}, volume={95}, number={A8}, year={1990}, month={Aug}, pages={12187-95}, abstract={ Radio waves at frequencies between 1525 and 5925 Hz were observed on the DE 1 satellite during a pass over the Heating facility of the Max-Planck-Institut fur Aeronomie (MPAe Heating) near Tromso, Norway. The waves were detected during a 2-min period on December 12, 1981, and measurements indicated pulse stretching by a few hundred milliseconds and spectral broadening of about 10 Hz. Measured signal delays are compared with those calculated using three-dimensional ray tracing. Scattering by density irregularities may be responsible for the observed long delays and spectral broadening }, keywords={ ionospheric electromagnetic wave propagation plasma radiofrequency heating radiowave propagation radiowave heating AD 1981 12 12 MF ELF/VLF waves ionospheric heater DE 1 satellite MPAe Heating pulse stretching spectral broadening signal delays density irregularities 1525 Hz 5925 Hz 2.759 MHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{RosenbergMay90, author={Rosenberg, T.J. and Wei, R. and Detrick, D.L. and Inan, U.S.}, title={ Observations and modeling of wave-induced microburst electron precipitation }, journal={Journal of Geophysical Research}, volume={95}, number={A5}, year={1990}, month={May}, pages={6467-75}, abstract={ Energy-time features of X-ray microbursts are examined and compared with the predictions of a test particle simulation model of wave-induced electron precipitation resulting from gyroresonant wave-particle interactions in the magnetosphere. The observations were obtained on a balloon flight at Siple station, Antarctica (L approximately=4.2) on December 30, 1980. The energy and time evolution of the microbursts were studied for X-rays in the energy range from 25 to 175 keV. The authors identify the narrow microbursts with electrons which are precipitated directly after undergoing pitch-angle scattering interactions with the wave pulse; the wide microbursts are identified with electrons which, after interacting with the wave, mirror in the conjugate ionosphere before precipitating into the southern ionosphere. In general, the results provide further support for the gyroresonant test particle simulation model, and for the belief that the observed type of microbursts originates in the vicinity of the magnetic equator in a gyroresonant process involving discrete chorus emissions }, keywords={ atmospheric electron precipitation atmospheric radiation magnetosphere radiation belts AD 1980 12 30 ionosphere radiation belt wave-induced microburst electron precipitation X-ray microbursts test particle simulation model gyroresonant wave-particle interactions magnetosphere pitch-angle scattering interactions 25 to 175 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanMay90, author={Inan, U.S.}, title={ VLF heating of the lower ionosphere }, journal={Geophysical Research Letters}, volume={17}, number={6}, year={1990}, month={May}, pages={729-32}, abstract={ A controlled wave-injection experiment with a 28.5 kHz transmitter having a radiated power of 100 kW has revealed evidence of ionospheric heating by the VLF waves. Calculations indicate that the observed effect can be attributed to the absorption of wave energy in the lower ionosphere, which is estimated to result in a 30% enhancement in the collision frequency at 85 km. This process also represents a new means of direct coupling of lightning energy to the lower ionosphere }, keywords={ atmospherics ionosphere lightning radiowave heating experiment atmospherics ionospheric modification VLF heating lower ionosphere wave-injection experiment absorption wave energy direct coupling lightning energy 28.5 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{HelliwellApr90, author={Helliwell, R.A. and Mielke, T. and Inan, U.S.}, title={ Rapid whistler-mode wave growth resulting from frequency-time curvature }, journal={Geophysical Research Letters}, volume={17}, number={5}, year={1990}, month={Apr}, pages={599-602}, abstract={ The rapid (<50 ms) temporal growth of ducted whistlers is simulated using controlled injection of VLF pulses from the Siple Station, Antarctica transmitter. The results show that, when the frequency-time function of the injected pulse has a positive slope and negative curvature, producing a kind of 'chirp' such that it approximates the f(t) shape of a lightning-generated whistler at frequencies above the 'nose' frequency, growth up to a saturation level (20-30 dB) commonly occurs within <50 ms as opposed to 200-300 ms that is required for monochromatic input signals. The phenomenon is explained in terms of second-order-resonance theory }, keywords={ whistlers whistlers EM wave rapid growth whistler-mode wave growth frequency-time curvature ducted whistlers controlled injection VLF pulses Siple Station injected pulse second-order-resonance theory }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GailJan90, author={Gail, W.B. and Inan, U.S.}, title={ Characteristics of wave-particle interactions during sudden commencements. 2. Spacecraft observations }, journal={Journal of Geophysical Research}, volume={95}, number={A1}, year={1990}, month={Jan}, pages={139-47}, abstract={ For pt.I see ibid., vol.95, no.A1, p.110-37 (1990). Wave data from the DE 1 spacecraft for 50 sudden commencements were analyzed for amplitude and spectral modifications and correlated with data from ground-based observatories. Changes in wave activity were identified in 14 of the events studied. The changes, which were commonly observed at frequencies below the local electron gyrofrequency, exhibited a complex structure both in frequency and in time and varied considerably among events }, keywords={ magnetic storms magnetospheric electromagnetic wave propagation plasma radiowave propagation spacecraft observations magnetic storms magnetosphere plasma amplitude modification wave-particle interactions sudden commencements DE 1 spectral modifications wave activity 0.3 to 30 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GailJan90, author={Gail, W.B. and Inan, U.S. and Helliwell, R.A. and Carpenter, D.L. and Krishnaswamy, S. and Rosenberg, T.J. and Lanzerotti, L.J.}, title={ Characteristics of wave-particle interactions during sudden commencements. 1. Ground-based observations }, journal={Journal of Geophysical Research}, volume={95}, number={A1}, year={1990}, month={Jan}, pages={119-37}, abstract={ ELF-VLF (0.3-30 kHz) wave data measured at ground-based observatories for 250 sudden commencements were analyzed for amplitude and spectral modifications and correlated with magnetic field and precipitating particle observations. Changes in ELF-VLF wave activity at high-latitude stations were observed in 50-60% of the events studied and for approximately 80% of the events when the observing station was on the dayside. Characteristic, well-defined modifications of both coherent and incoherent ELF-VLF wave emissions were observed }, keywords={ magnetic storms magnetospheric electromagnetic wave propagation plasma radiowave propagation ELF VLF ground based observation magnetosphere plasma magnetic storm amplitude modification wave-particle interactions sudden commencements spectral modifications magnetic field precipitating particle wave activity 0.3 to 30 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BurgessMar90, author={Burgess, W.C. and Inan, U.S.}, title={ Simultaneous disturbance of conjugate ionospheric regions in association with individual lightning flashes }, journal={Geophysical Research Letters}, volume={17}, number={3}, year={1990}, month={Mar}, pages={259-62}, abstract={ Characteristic whistler-associated amplitude perturbations of subionospheric VLF or LF signals ('Trimpi events') observed within one second of each other at Palmer Station, Antarctica and at Arecibo, Puerto Rico suggest that ionospheric regions in both northern and southern hemispheres are disturbed together in association with individual lightning flashes. During a one hour period on March 21, 1989, the onsets of 44 out of 47 perturbations measured on a 21.4 kHz signal from Maryland to Arecibo occurred within 1 s of perturbation onsets measured on a 23.4 kHz signal from Hawaii to Palmer Station. Similar activity occurred before and after this period, and on the preceding and following days. The observations are consistent with the disturbance of geomagnetically conjugate ionospheric regions by multiple bounces between hemispheres of bursts of radiation belt electrons, scattered in pitch angle by whistlers in the magnetosphere. Analysis of patterns of perturbations with corresponding whistler and lightning information from this period suggests that there were at least two distinct ionospheric disturbances in each hemisphere }, keywords={ ionosphere whistlers ionosphere conjugate region Trimpi event AD 1989 03 21 disturbance lightning flashes whistler-associated amplitude perturbations VLF LF Palmer Station Antarctica Arecibo Puerto Rico magnetosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{PoulsenMar90, author={Poulsen, W.L. and Bell, T.F. and Inan, U.S.}, title={ Three-dimensional modeling of subionospheric VLF propagation in the presence of localized D region perturbations associated with lightning }, journal={Journal of Geophysical Research}, volume={95}, number={A3}, year={1990}, month={Mar}, pages={2355-66}, abstract={ A theoretical model of single-mode, subionospheric VLF wave propagation in the presence of localized perturbations of the nighttime D region has been developed. Values for changes in the amplitude and phase of a received signal were obtained and compared with amplitude and phase measurements of a VLF signal received at Palmer Station, Antarctica, from the NPM transmitter (23.4 kHz) in Hawaii during energetic electron precipitation events. Positive phase and/or negative amplitude shifts in the received signal are produced by perturbations centered on the great circle (GC) path, whereas both positive and negative amplitude (or phase) shifts in a single-mode signal can be produced by perturbations lying in regions off the GC path. The magnitude of the signal scattered by the perturbation towards the receiver continuously decreases with distance away from the GC path, becoming insignificant beyond approximately 20 lambda . On or near the GC path, the magnitude of the scattered signal was proportional to the scale of the perturbation parallel to the GC path }, keywords={ atmospheric electromagnetic wave propagation atmospheric electron precipitation atmospheric ionisation D-region ionospheric electromagnetic wave propagation plasma radiowave propagation upper atmosphere D-region lightning-induced perturbations night-time D-region single-mode VLF wave propagation received signal amplitude changes signal phase changes positive phase shifts negative phase shifts negative amplitude shifts scattered radio signal strength ionisation perturbation location perturbation scale size single waveguide mode theory subionospheric VLF propagation localized perturbations VLF signal Palmer Station Antarctica NPM transmitter Hawaii energetic electron precipitation events negative amplitude shifts single-mode signal 23.4 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{ImhofAug89, author={Imhof, W.L. and Voss, H.D. and Mobilia, J. and Walt, M. and Inan, U.S. and Carpenter, D.L.}, title={ Characteristics of short-duration electron precipitation bursts and their relationship with VLF wave activity }, journal={Journal of Geophysical Research}, volume={94}, number={A8}, year={1989}, month={Aug}, pages={10079-93}, abstract={ Energetic (>6 keV) electron data from the SEEP payload on the low altitude ( approximately 200 km) polar orbiting S81-1 satellite indicate a high rate of occurrence of short duration (<0.6 s) electron precipitation bursts. Characteristics of events observed at night (2230 MLT) versus daytime (1030 MLT) and at midlatitudes (23) were distinctly different in several ways. Comparison of the electron data with simultaneous VLF wave data from Palmer (L approximately=2.4) and Siple (L approximately=4.3) stations in Antarctica indicated a varying degree of association of electron bursts with whistlers and chorus emissions. Several of the electron bursts observed at nighttime and at 23) were observed on satellite passes within +or-50 degrees of the Siple meridian, chorus was invariably detected at Siple, but correlation of electron bursts with individual chorus spectral elements was not evident }, keywords={ atmospheric electron precipitation whistlers radiowave emission magnetosphere ionosphere short-duration electron precipitation bursts VLF wave activity whistlers chorus lightning-generated }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarJun89, author={Sonwalkar, V.S. and Inan, U.S.}, title={ Lightning as an embryonic source of VLF hiss }, journal={Journal of Geophysical Research}, volume={94}, number={A6}, year={1989}, month={Jun}, pages={6986-94}, abstract={ Data from the DE 1 satellite show that lightning-generated whistlers often trigger hiss emissions that endure for up to 10- and 20-s periods. The data consist of the measured electric and magnetic fields in the frequency range of 1.5 kHz to 6.0 kHz, during 22 DE 1 passes during the period December 28, 1986 to January 18, 1987. The 22 passes covered L shells of 3.4 to 5.1 and geomagnetic latitude of 20 degrees N to 40 degrees S in the afternoon ( approximately 1400-1500 MLT) sector. The whistler-triggered hiss emissions were observed on 16 of the passes, and they generally exhibited the following characteristics: emission spectra were wide band (1-2 kHz) and rather structureless; and well-defined and sustained fading patterns were observed at twice the spin frequency over 10- to 20-s periods. These results indicate that lightning-generated whistlers may be an important embryonic source for magnetospheric hiss and that whistlers and emissions triggered by them often constitute the dominant wave activity in the approximately 1.5- to 6-kHz range during geomagnetically quiet periods }, keywords={ atmospheric electron precipitation atmospheric proton precipitation atmospheric spectra atmospherics lightning magnetosphere radiation belts wideband structureless emission spectra ELF magnetosphere electric fields L-shells 3.4 to 5.1 afternoon sector wave normal angle trapped electrons loss ring current protons precipitation AD 1986 12 28 to 1987 01 18 VLF hiss DE 1 satellite lightning-generated whistlers hiss emissions magnetic fields DE 1 passes December 28, 1986 to January 18, 1987 geomagnetic latitude whistler-triggered hiss emissions sustained fading patterns spin frequency embryonic source magnetospheric hiss dominant wave activity geomagnetically quiet periods 1.5 to 6.0 kHz 3.4 to 5.1 Earthradii 0.5 to 50 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanFeb89, author={Inan, U.S. and Walt, M. and Voss, H.D. and Imhof, W.L.}, title={ Energy spectra and pitch angle distributions of lightning-induced electron precipitation: analysis of an event observed on the S81-1 (SEEP) satellite }, journal={Journal of Geophysical Research}, volume={94}, number={A2}, year={1989}, month={Feb}, pages={1379-401}, abstract={ Temporal and spectral signatures of a lightning-induced electron precipitation (LEP) burst observed on the S81-1 (SEEP) satellite are analyzed and compared with the predictions of a test particle model of the gyroresonant whistler-particle interaction in the magnetosphere. The flux to be detected by specific detectors on the low altitude ( approximately 220 km) satellite at L approximately=2.24 is calculated in terms of the integral counting rate as a function of time and in terms of the dynamic energy spectra during the initial approximately 300-ms precipitation pulse. For a whistler wave packet with frequency range 500 Hz to 6 kHz the dynamic energy spectra are found to depend sensitively on the electron angular distribution in the vicinity of the loss cone. In the case of a whistler wave originating in northern hemisphere lightning the maximum whistler-induced pitch angle scattering of electrons occurs near approximately 10 degrees S geomagnetic latitude }, keywords={ atmospheric electron precipitation ionosphere magnetosphere ionosphere wave particle interaction pitch angle distributions lightning-induced electron precipitation burst test particle model gyroresonant whistler-particle interaction magnetosphere whistler wave }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{GurnettMay88, author={Gurnett, D.A. and Inan, U.S.}, title={ Plasma wave observations with the Dynamics Explorer 1 spacecraft }, journal={Reviews of Geophysics}, volume={26}, number={2}, year={1988}, month={May}, pages={285-316}, abstract={ Reviews the results from the plasma wave instrument on the Dynamics Explorer 1 (DE 1) spacecraft. The DE 1 spacecraft was launched on August 3, 1981, into an elliptical polar orbit with initial perigee and apogee radial distances of 1.09 and 4.65 R/sub E/. In the roughly 6 years since the launch of the spacecraft, DE 1 has provided basic new information on a wide variety of magnetospheric plasma wave phenomena. These include auroral kilometric radiation, auroral hiss, Z mode radiation, narrow-band electromagnetic emissions associated with equatorial upper hybrid waves, whistler mode emissions, wave-particle interactions stimulated by ground VLF transmitters, equatorial ion cyclotron emissions, ion Bernstein mode emissions, and electric field turbulence along the auroral field lines. The authors first give a brief review of the basic plasma wave modes that can exist in the equatorial and polar regions of the magnetosphere. After the basic terminology is established, each of the above areas of plasma wave research is discussed in detail }, keywords={ magnetosphere reviews AD 1981 to 1987 DE satellite plasma wave ionosphere magnetosphere EM wave radiowave emissions Dynamics Explorer 1 auroral kilometric radiation auroral hiss Z mode radiation narrow-band electromagnetic emissions equatorial upper hybrid waves whistler mode emissions wave-particle interactions }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanOct88, author={Inan, U.S. and Shafer, D.C. and Yip, W.Y. and Orville, R.E.}, title={ Subionospheric VLF signatures of nighttime D region perturbations in the vicinity of lightning discharges }, journal={Journal of Geophysical Research}, volume={93}, number={A10}, year={1988}, month={Oct}, pages={11455-72}, abstract={ A 12-hour sequence of perturbations of subionospheric VLF signals observed in association with lightning provided preliminary evidence that the ionospheric regions perturbed in these events may be confined to within approximately 150 km of the lightning discharges, and that intracloud flashes as well as cloud-to-ground lightning may be important in producing the perturbations. High-resolution analysis of event signatures indicated the presence of two different classes of events. For one set of events, observed during the most active central 6 hours of the observation period, a approximately 0.6-s delay between the causative lightning and VLF event onset and a approximately 1-s onset duration was observed, consistent with previously suggested models of the gyroresonant whistler-particle interaction that leads to particle precipitation and perturbation of the Earth-ionosphere waveguide. However, another set of events, observed during the first 2 hours of the observation period, exhibited a very different temporal signature, characterized by a much smaller (<50 ms) delay and sometimes also very short (<50 ms) rise times }, keywords={ atmospheric radiation D-region lightning whistlers night radiowave emission D-region ionosphere perturbation AD 1987 03 nighttime lightning discharges subionospheric VLF signals gyroresonant whistler-particle interaction particle precipitation Earth-ionosphere waveguide }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanSep88, author={Inan, U.S. and Wolf, T.G. and Carpenter, D.L.}, title={ Geographic distribution of lightning-induced electron precipitation observed as VLF/LF perturbation events }, journal={Journal of Geophysical Research}, volume={93}, number={A9}, year={1988}, month={Sep}, pages={9841-53}, abstract={ Expected occurrence characteristics of lightning-induced electron precipitation (LEP) events at longitudes of the western (110 degrees W) versus eastern (71 degrees W) United States are considered from the point of view of available trapped particle flux at the edge of the loss cone. Considering published data on nighttime fluxes of >68 keV electrons observed at L approximately=2.5, and for 'direct' precipitation into the northern hemisphere induced by northern hemisphere lightning, the occurrence rate and flux levels are expected to be a factor of 20-200 higher in the west than in the east, assuming no significant variation in lightning source activity with longitude. Again assuming lightning sources in the north, it is predicted that at 71 degrees W, 'mirrored' precipitation into the southern hemisphere would involve precipitation fluxes 30-300 times higher than 'direct' precipitation into the northern hemisphere. However, at 110 degrees W and again assuming lightning in the north, southern hemisphere precipitation would tend to be limited to that small fraction of particles that were initially scattered into the northern loss cone and that were then backscattered from the northern atmosphere so as to reach the south }, keywords={ atmospheric electron precipitation ionosphere magnetosphere atmospherics LEP ionosphere magnetosphere lightning-induced electron precipitation United States available trapped particle flux occurrence rate }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarJul88, author={Sonwalkar, V.S. and Inan, U.S.}, title={ Wave normal direction and spectral properties of whistler mode hiss observed on the DE 1 satellite }, journal={Journal of Geophysical Research}, volume={93}, number={A7}, year={1988}, month={Jul}, pages={7493-514}, abstract={ A new study of magnetospheric hiss as a spatially and temporally enduring phenomenon is undertaken using a recently developed formalism that allows the representation of hiss by a field distribution function (FDF). This formalism explicitly takes into account the whistler mode relationships and the linear and spin motion of the satellite, so that on a spin-stabilized satellite, it becomes possible to measure the wave propagation direction(s) from the observed fading patterns in the received electromagnetic field data. The authors have analyzed hiss signals received by electric and magnetic field antennae aboard the DE 1 satellite during a approximately 3-hour period on September 23, 1983. A band of hiss at frequencies <2 kHz was observed continuously from 0236 UT t0 0539 UT over a range of geomagnetic latitudes from lambda /sub m/=45 degrees N to lambda /sub m/=20 degrees S and L shells of L=4.3 to L=5.3. Electron density deduced from in situ and remote measurements indicate that during this time the DE 1 satellite was near the boundary of the plasmasphere. The observations are summarized }, keywords={ atmospheric radiation magnetosphere whistlers radiowave emission wave normal direction magnetosphere ELF AD 1983 09 23 VLF spectral properties whistler mode hiss magnetospheric hiss field distribution function formalism wave propagation direction boundary plasmasphere 1 to 4 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanFeb88, author={Inan, U.S. and Burgess, W.C. and Wolf, T.G. and Shafer, D.C. and Orville, R.E.}, title={ Lightning-associated precipitation of MeV electrons from the inner radiation belt }, journal={Geophysical Research Letters}, volume={15}, number={2}, year={1988}, month={Feb}, pages={172-5}, abstract={ Transient perturbations of subionospheric very low frequency radiowave signals provide new evidence for lightning-induced electron precipitation events involving (<1 s) bursts of >1 MeV electrons from the Earth's inner radiation belt at L30. The emissions may be generated near the equatorial plane at frequencies of approximately 0.2 F/sub Heq/ inside and approximately 0.35 f/sub Heq/ outside the plasmapause. The parallel energy of electrons for gyroresonance with the observed waves is found to be approximately 20-50 keV in both cases }, keywords={ atmospherics dispersion (wave) ionospheric electromagnetic wave propagation magnetic storms magnetosphere magnetospheric electromagnetic wave propagation whistlers emission elements bandwidth K/sub p/-index plasmasphere burstlike emissions emission elements dispersion equatorial whistlers source ISIS-2 satellite gyroresonant electrons parallel energy ionospheric reflections discrete VLF emission discrete whistler mode emission magnetosphere lower cutoff frequency equatorial electron gyrofrequency chorus emissions plasmapause early morning local time sector geomagnetic activity equatorial plane 1 to 5 kHz 5 to 25 kHz 2 to 4 Earthradii }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{FishmanFeb88, author={Fishman, G.J. and Inan, U.S.}, title={ Observation of an ionospheric disturbance caused by a gamma-ray burst }, journal={Nature}, volume={331}, number={6155}, year={1988}, month={Feb}, pages={418-209}, abstract={ Reports a first observation of an ionospheric disturbance from a gamma-ray burst. The burst, GB 830801, occurred at 22:14:18 UT on 1 August 1983 and was one of the strongest ever observed. The total fluence was 2*10/sup -3/ erg cm/sup -2/, most of which occurred in the first 4 s of the burst. Simultaneously, a change was observed in the amplitude of a very-low-frequency (VLF) radio signal from a transmitter in Rugby, England, monitored at Palmer Station, Antarctica, indicative of an ionospheric disturbance. Weaker disturbances were also recorded at the same time receiving site on signals from VLF stations in Annapolis, Maryland and Lualualei, Hawaii. The times of the burst and the disturbances are coincident within the 10-s resolution of the VLF recording system. No similar disturbances were observed within 60 h around the time of the burst. In the future, a network of VLF burst monitors may provide measurements of the total ionizing energy fluence from a burst, as well as some limited directional information }, keywords={ atmospheric ionisation gamma-ray sources (astronomical) ionosphere X-ray sources atmospheric ionisation ionospheric disturbance gamma-ray burst GB 830801 1 August 1983 total fluence VLF times resolution total ionizing energy fluence }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr87, author={Inan, U.S.}, title={ Waves and instabilities }, journal={Reviews of Geophysics}, volume={25}, number={3}, year={1987}, month={Apr}, pages={588-98}, abstract={ This review concentrates on US research activities in the area of waves and instabilities during the mid-1982 to mid-1986 period. Plasma waves and instabilities are phenomena that are central to the energization, acceleration, transport, and loss of energetic particles in magnetized plasmas. As such, they play a dominant role in almost all energy exchange phenomena that occur in planetary magnetospheres. The US research can be somewhat arbitrarily divided into the following six categories: (1) whistler mode wave-electron interactions, (2) wave-induced particle precipitation, (3) ULF wave phenomena, (4) ion-mode waves and instabilities, (5) auroral kilometric radiation, (6) ionospheric irregularities and instabilities, and (7) waves and instabilities in the outer magnetosphere }, keywords={ ionosphere magnetosphere reviews plasma wave magnetosphere plasma stability whistler mode wave-electron interactions wave-induced particle precipitation ULF wave phenomena ionospheric }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{CarpenterApr87, author={Carpenter, D.L. and Inan, U.S.}, title={ Seasonal, latitudinal and diurnal distributions of whistler-induced electron precipitation events }, journal={Journal of Geophysical Research}, volume={92}, number={A4}, year={1987}, month={Apr}, pages={3429-35}, abstract={ The seasonal, latitudinal, and diurnal distributions of whistler-induced electron precipitation events, detected as subionospheric signal perturbations (Trimpi events), have been studied by means of data sets acquired in 1982-3 at Palmer and Siple stations, Antarctica. The authors also compare simultaneous records from L approximately 2.4 and L approximately 4.3, and find evidence of an inner magnetospheric maximum in burst precipitation activity for E>40 keV in the range L approximately 2-3, consistent with theoretical predictions }, keywords={ atmospheric electron precipitation whistlers AD 1982 to 1983 VLF seasonal variation latitudinal variation diurnal distributions whistler-induced electron precipitation events subionospheric signal perturbations Trimpi events Palmer Siple Antarctica inner magnetospheric maximum burst precipitation activity }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr87, author={Inan, U.S. and Carpenter, D.L.}, title={ Lightning-induced electron precipitation events observed at L approximately 2.4 as phase and amplitude perturbations on subionospheric VLF signals }, journal={Journal of Geophysical Research}, volume={92}, number={A4}, year={1987}, month={Apr}, pages={3293-303}, abstract={ Lightning-induced electron precipitation (LEP) events are studied using the Trimpi effect, in which the precipitation-induced ionization enhancements in the lower ionosphere (D region) give rise to rapid perturbations of subionospheric VLF signals. In 1983, the phase and amplitude of signals from the NPM transmitter in Hawaii (23.4 kHz) and the Omega transmitter in Argentina (12.9 kHz) were measured at Palmer, Antarctica (L approximately 2.4), together with the magnetospheric whistler background. The long baseline and over-sea great circle paths from these two sources make it possible for the observed perturbations to be interpreted using a single waveguide mode theory. Analytical expressions are used to relate the magnitude of the phase perturbations to differential changes in ionospheric reflection height along a segment of the propagation path. The predicted relationship between relative perturbation sizes on the two different signals is compared with measurements. From this information, the whistler-induced flux levels are inferred to be in the 10/sup -4/-10/sup -2/ erg cm/sup -2/ s/sup -1/ range and the precipitation regions are inferred to be roughly 'circular' in shape, rather than elongated along L shells }, keywords={ atmospheric electron precipitation ionospheric electromagnetic wave propagation AD 1983 phase perturbation radiowave propagation lightning induced ionosphere D-region electron precipitation events amplitude perturbations subionospheric VLF signals Trimpi effect precipitation-induced ionization enhancements lower ionosphere whistler }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{HurrenAug86, author={Hurren, P.J. and Smith, A.J. and Carpenter, D.L. and Inan, U.S.}, title={ Burst precipitation induced perturbations on multiple VLF propagation paths in Antarctica }, journal={Annales Geophysicae, Series A (Upper Atmosphere and Space Sciences)}, volume={4}, number={4}, year={1986}, month={Aug}, pages={311-18}, abstract={ The burst precipitation of energetic (E>40 keV) electrons near L=4 has been detected as amplitude perturbations (Trimpi events) on subionospheric 3.79 kHz CW signals from the Siple (L=4.2) VLF transmitter that were observed at Halley (L/sup -/=4.3), Palmer (L=2.3) and South Pole ( Lambda =74 degrees ) Antarctic stations. The observations were made on the dayside of the Earth but beneath a locally dark ionosphere during a generally disturbed 6 d period in July 1982 when the plasmapause projection was equatorward of the Siple-Halley and Siple-South Pole paths }, keywords={ atmospheric electron precipitation ionospheric electromagnetic wave propagation radiowave propagation ionosphere radiowave energetic electrons AD 1982 07 12 to 17 multiple VLF propagation paths Antarctica burst precipitation amplitude Trimpi events CW signals Siple Halley Palmer South Pole plasmapause projection 3.79 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanJan87, author={Inan, U.S.}, title={ Gyroresonant pitch angle scattering by coherent and incoherent whistler mode waves in the magnetosphere }, journal={Journal of Geophysical Research}, volume={92}, number={A1}, year={1987}, month={Jan}, pages={127-42}, abstract={ A test particle approach is used to compare gyroresonant pitch angle scattering of energetic electrons by coherent versus incoherent whistler mode waves, for the case in which the coherent wave amplitude is below the nonlinear phase trapping threshold. Wave packets of 400 ms duration propagating along the magnetic field at L=4 within the plasmasphere are considered, and the wave-induced pitch angle scattering along the propagation path from one hemisphere to the other and the resulting precipitation flux are computed. An incoherent wave spectrum is simulated by random modulation of the wave frequency at intervals of 1 ms, thereby generating signals with nearly constant power spectral density over a bandwidth of 2 kHz centered at 5.5 kHz. The associated pitch angle scattering is compared with that of a monochromatic 5.5 kHz signal of 400 ms duration. Results of the test particle analysis are compared with those expected on the basis of a classical diffusion treatment }, keywords={ atmospheric elementary particle precipitation magnetospheric electromagnetic wave propagation plasma radiation belts whistlers EM wave atmosphere VLF radiation belt plasma incoherent whistler mode waves magnetosphere test particle approach gyroresonant pitch angle scattering energetic electrons coherent wave amplitude nonlinear phase trapping threshold magnetic field plasmasphere precipitation flux wave spectrum random modulation wave frequency power spectral density classical diffusion treatment 5.5 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{TolstoyDec86, author={Tolstoy, A. and Rosenberg, T.J. and Inan, U.S. and Carpenter, D.L.}, title={ Model predictions of subionospheric VLF signal perturbations resulting from localized, electron precipitation-induced ionization enhancement regions }, journal={Journal of Geophysical Research}, volume={91}, number={A12}, year={1986}, month={Dec}, pages={13473-82}, abstract={ Whistler-induced precipitation of energetic electrons produces transient ionospheric conductivity variations that perturb the amplitude and phase of VLF signals propagating in the Earth-ionosphere waveguide. This study uses a waveguide mode theoretic propagation model to predict the effect of localized ionization enhancement (IE) regions on nighttime long-path VLF signals from the US Navy navigational transmitters NSS, NAA, NLK and NPM to Antarctic receiving stations. The predictions are then compared with the observed signal behavior in Trimpi events from which inferences can be drawn about an IE region's approximate characteristics. The study also examines the effects of transmitter-induced electron precipitation on the VLF signals }, keywords={ atmospheric electricity atmospheric electron precipitation atmospheric ionisation ionosphere ionospheric electromagnetic wave propagation radiowave propagation D-region whistlers atmosphere radiowave subionospheric VLF signal perturbations electron precipitation-induced ionization enhancement regions transient ionospheric conductivity variations amplitude phase Earth-ionosphere waveguide propagation nighttime US Navy navigational transmitters Antarctic receiving stations Trimpi events }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr86, author={Inan, U.S.}, title={ Jovian VLF chorus and Io torus aurora }, journal={Journal of Geophysical Research}, volume={91}, number={A4}, year={1986}, month={Apr}, pages={4543-50}, abstract={ A test particle model of the cyclotron resonance interaction of waves and trapped radiation belt particles is used to estimate the energetic electron fluxes precipitated by Jovian VLF chorus waves observed on the Voyager 1 and 2 spacecraft near the Io torus. The precipitation fluxes induced by 1-s-long chorus wave packets at L approximately=7.6 and 8.6 are estimated to be bursts of approximately 5 s duration with a peak of 0.3-3 and 0.7-7 ergs/cm/sup 2/ s that consist of electrons of approximately 5-100 keV energy and that arrives at the ionosphere approximately 15 s after the generation of the chorus wave at the equatorial plane. The effects in the Jovian ionosphere of the chorus-induced precipitation are estimated using existing ionospheric models }, keywords={ Jupiter planetary atmospheres planetary satellite atmospheres Jupiter planetary atmosphere radiowave emission plasma torus magnetosphere electron precipitation VLF chorus Io torus aurora test particle model cyclotron resonance interaction radiation belt energetic electron fluxes ionosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{HelliwellApr86, author={Helliwell, R.A. and Carpenter, D.L. and Inan, U.S. and Katsufrakis, J.P.}, title={ Generation of band-limited VLF noise using the Siple transmitter: a model for magnetospheric hiss }, journal={Journal of Geophysical Research}, volume={91}, number={A4}, year={1986}, month={Apr}, pages={4381-92}, abstract={ Band-limited VLF noise generated by the experimental transmitter at Siple Station, Antarctica, is used to simulate the interaction of natural magnetospheric hiss with energetic radiation belt particles. While the observed spectrum of the generated noise at times closely resembles that of natural VLF hiss, at other times discrete emissions are found to be generated from the incoherent noise signal. Results imply that magnetospheric chorus can be triggered by hiss signals, indicating the similarity of generation mechanisms for coherent and incoherent VLF emissions. A model based on second-order cyclotron resonance can explain the conversion of the relatively short duration wavelets of a hiss spectrum into the longer, semicoherent discrete emissions that are typical of chorus }, keywords={ magnetosphere radiowave emission generation wave particle interaction band-limited VLF noise model magnetospheric hiss interaction natural radiation belt particles discrete emissions chorus generation mechanisms }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanMar86, author={Inan, U.S. and Carpenter, D.L.}, title={ On the correlation of whistlers and associated subionospheric VLF/LF perturbations }, journal={Journal of Geophysical Research}, volume={91}, number={A3}, year={1986}, month={Mar}, pages={3106-16}, abstract={ Several periods of whistler-associated subionospheric signal perturbations (i.e. Trimpi events) observed at Palmer, Antarctica (L approximately 2.4) have been studied. In a case study of the time signature of the signal perturbations during a 10-min recording period on March 30, 1983, the time delay between the whistler-producing spheric and the onset of the change was found to be in the range 0.52-0.62 s, independent of the amplitude of the change. Event amplitude, as expected from previous work, was found to be well correlated with the associated whistler wave intensity. Other temporal features such as the rise and decay times of the perturbations were also found to be independent of the event amplitude. These results are consistent with a recent theoretical model of gyroresonant particle scattering interaction in the magnetosphere }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation whistlers associated subionospheric perturbations VLF LF magnetosphere AD 1983 03 Trimpi event correlation whistlers spheric onset gyroresonant particle scattering interaction magnetosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SonwalkarJan86, author={Sonwalkar, V.S. and Inan, U.S.}, title={ Measurements of Siple transmitter signals on the DE 1 satellite: wave normal direction and antenna effective length }, journal={Journal of Geophysical Research}, volume={91}, number={A1}, year={1986}, month={Jan}, pages={154-64}, abstract={ A new experimental technique is developed to simultaneously measure the wave propagation direction and the effective length of a small (L<< lambda ) electric dipole antenna on a spin stabilized satellite in the magnetosphere. The technique relies on the near simultaneous measurement of single components of the electric and magnetic fields of a coherent VLF signal injected into the medium from a ground-based source. The spin fading characteristics of the signal received by the electric dipole and the magnetic loop antenna permit the measurement of the wave normal direction. Measurements of the local cold plasma density are used to determine the refractive index. The wave electric field is then inferred from the wave magnetic field as measured on the loop antenna, the refractive index and the direction of propagation. Comparing this electric field with the measured voltage across the dipole antenna leads to the effective length of the receiving electric dipole }, keywords={ artificial satellites atmospheric electricity atmospheric techniques geomagnetism magnetosphere magnetospheric electromagnetic wave propagation whistlers VLF whistler mode signals small dipole antenna magnetosphere EM wave propagation HZ 4025 signal electric fields components AD 1982 07 28 dipole antenna voltage magnetospheric technique Earth radii 004.5 to 005.5 Siple transmitter signals DE 1 satellite wave normal direction antenna effective length wave propagation direction electric dipole antenna spin stabilized satellite near simultaneous measurement single components magnetic fields coherent VLF signal ground-based source spin fading characteristics magnetic loop antenna local cold plasma density refractive index wave electric field wave magnetic field receiving electric dipole }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{HelliwellJan86, author={Helliwell, R.A. and Inan, U.S. and Katsufrakis, J.P. and Carpenter, D.L.}, title={ Beat excitation of whistler mode sidebands using the Siple VLF transmitter }, journal={Journal of Geophysical Research}, volume={91}, number={A1}, year={1986}, month={Jan}, pages={143-53}, abstract={ The process of whistler mode sideband generation in the magnetosphere is studied by transmitting two monochromatic signals closely spaced in frequency ( Delta f=5-45 Hz) from the experimental VLF transmitter at Siple Station, Antarctica. The signals were observed following ducted magnetospheric propagation to the conjugate station at Roberval, Quebec. Sidebands up to seventh order were generated extending to +or-100 Hz with respect to the average frequency of the carriers. New frequencies were observed both under conditions of little or no growth of the input signals and when one of the input signals did grow significantly. A small signal mechanism is proposed in which emissions are triggered by each beat between the input waves but are then suppressed by the following beat. The energy from the phase bunched particles is believed to feed preferentially into the sidebands. The observed process of sideband generation provides a mechanism to break down the coherence of relatively narrowband waves in the magnetosphere and may account for the transformation of relatively coherent wave packets into broader more variable bands of noiselike signals }, keywords={ atmospherics magnetosphere magnetospheric electromagnetic wave propagation whistlers whistler sidebands beat excitation ELF atmospherics magnetosphere EM wave propagation two-frequency signal seventh-order sidebands carriers average frequency input signals growth rate phase bunched particles energy VLF emissions triggering Hz 2200 to 3800 AD 1983 06 30 AD 1983 07 11 Siple VLF transmitter whistler mode sideband generation monochromatic signals Siple Station Antarctica ducted magnetospheric propagation conjugate station Roberval Quebec small signal mechanism relatively coherent wave packets noiselike signals }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{DejnakarintraDec85, author={Dejnakarintra, M. and Inan, U.S. and Carpenter, D.L.}, title={ Transient tropospheric electric fields resulting from sudden changes in ionospheric conductivity }, journal={Journal of Geophysical Research}, volume={90}, number={A12}, year={1985}, month={Dec}, pages={12271-81}, abstract={ The transient electric fields that would be generated by sudden changes in the atmospheric conductivity profile are estimated using a theoretical model. The model assumes the existence of a horizontal electric field with a spatial extent of >or=20-km at 150-km altitude and involves the solution of the boundary value problem in two dimensions. The geomagnetic field lines below 150-km altitude are assumed to be vertical, but the anisotropy of the medium above approximately 70-km altitude is fully accounted for. The computed electric field strength depends sensitively on the size of the source field as well as the conductivity profile of the atmosphere. During a transient the peak electric fields produced in the case of a small-scale source field can be considerably larger than those due to large-scale source distributions }, keywords={ atmospheric electricity troposphere troposphere transient electric field atmosphere electrical conductivity sudden changes ionospheric conductivity theoretical model horizontal electric field boundary value problem source field }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanAug85, author={Inan, U.S. and Carpenter, D.L. and Helliwell, R.A. and Katsufrakis, J.P.}, title={ Subionosphere VLF/LF phase perturbations produced by lightning-whistler induced particle precipitation }, journal={Journal of Geophysical Research}, volume={90}, number={A8}, year={1985}, month={Aug}, pages={7457-69}, abstract={ New evidence of phase perturbations of subionospheric VLF/LF signals, produced by lightning-whistler-induced precipitation of bursts of radiation belt electrons, is reported. Phase changes of 0.1-1.0 mu s on a 12.9-kHz signal arriving at Palmer, Antarctica (L approximately 2.4), over a approximately 2400-km path are regularly observed with a characteristic signature of a rapid (or=50 keV) into the nighttime lower ionosphere. The receiving stations, each approximately 1400 km from Siple, were located to the north at Palmer (L approximately 2.3), to the east at Halley (L approximately 4.3), and to the south at South Pole ( Lambda approximately 74 degrees ). Rapid changes in the received phase and amplitude of the Siple signal ('Trimpi events') were observed in conjunction with the reception of one-hop whistlers. Phase measurements appear to be a particularly sensitive means of detecting burst precipitation activity under experimental conditions of the kind described. The length and spatial distribution of the signal paths provide a basis for studying the occurrence and approximate location of burst precipitation in regions outside the observing range of most instruments used for detection of precipitation }, keywords={ atmospheric electron precipitation ionospheric techniques electron precipitation measurement technique ionosphere VLF method burst precipitation plasmapause occurrence nighttime lower ionosphere phase occurrence approximate location }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanJan85, author={Inan, U.S. and Chang, H.C. and Helliwell, R.A. and Imhof, W.L. and Reagan, J.B. and Walt, M.}, title={ Precipitation of radiation belt electrons by man-made waves: a comparison between theory and measurement }, journal={Journal of Geophysical Research}, volume={90}, number={A1}, year={1985}, month={Jan}, pages={359-69}, abstract={ The temporal and spectral shape and the absolute flux level of particle pulses precipitated by a VLF transmitter are examined from a theoretical point of view. A test-particle model of the gyroresonant wave-particle interactions is applied to the parameters of the observed cases for calculating the precipitation characteristics. The temporal shapes of the precipitation pulses are found to be controlled (1) by the pitch angle dependence of the particle distribution near the edge of the loss cone and (2) by the multiple interaction of the particles with the waves due to significant atmospheric backscatter }, keywords={ atmospheric electron precipitation magnetosphere radiation belts radiowave propagation magnetosphere electron precipitation artificial modification experiment transmitter induced radiation belt electrons man-made waves theory VLF test-particle model gyroresonant wave-particle interactions precipitation pulses }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{SmithJan85, author={Smith, A.J. and Carpenter, D.L. and Inan, U.S.}, title={ Whistler-triggered VLF noise bursts observed on the DE-1 satellite and simultaneously at Antarctic ground stations }, journal={Annales Geophysicae}, volume={3}, number={1}, year={1985}, month={Jan}, pages={81-8}, abstract={ Whistler-triggered bursts of very low frequency chorus in the 5-7 kHz range, occurring quasi-periodically every 3-5 min, have previously been observed at ground stations under conditions of relatively deep quieting following moderate magnetic disturbance. It was found that these wave bursts propagate outside the plasmapause and that they can induce detectable electron precipitation at ionospheric D-region altitudes. This paper reports simultaneous observations of such wave events on the ground at Antarctic stations Halley and Siple (L=4.3) and on the high altitude satellite DE-1 }, keywords={ atmospherics magnetosphere whistlers whistler-triggering chorus kHz 0005 to 0007 ducted propagation VLF noise bursts DE-1 satellite Antarctic ground stations electron precipitation ionospheric D-region Halley Siple high altitude satellite }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanFeb85, author={Inan, U.S. and Bell, T.F.}, title={ Spectral broadening of VLF transmitter signals observed on DE 1: a quasi-electrostatic phenomenon? }, journal={Journal of Geophysical Research}, volume={90}, number={A2}, year={1985}, month={Feb}, pages={1771-5}, abstract={ Spectrally broadened VLF transmitter signals are observed on the DE 1 satellite using alternatively both electric and magnetic field sensors. It is found that at times when the electric field component undergoes significant bandwidth expansion (up to approximately 110 Hz) the magnetic field component has a bandwidth of less than 10 Hz. The results support the theory that the off-carrier components are quasi-electrostatic in nature. Measurement of the absolute E and B field magnitudes of the broadened signals are used to determine the wave Poynting vector }, keywords={ ionospheric electromagnetic wave propagation radiowave propagation radiowave propagation quasielectrostatic ionosphere spectral broadening offcarrier transionospheric VLF transmitter signals theory off-carrier wave Poynting vector }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{ChangFeb85, author={Chang, H.C. and Inan, U.S.}, title={ Lightning-induced electron precipitation from the magnetosphere }, journal={Journal of Geophysical Research}, volume={90}, number={A2}, year={1985}, month={Feb}, pages={1531-41}, abstract={ Precipitation of radiation belt particles induced by whistlers that are generated by atmospheric lightning discharges and propagate over L shells of 2-4.5 is considered. Using a test particle model of the whistler-particle interaction, the energy spectra and temporal profile of whistler-induced fluxes as a function of L shell are quantitatively determined for representative plasmaspheric cold plasma distribution. Results indicate that for higher energy electron precipitation (E>40 keV) there exists an inner magnetospheric region (250 on the active VLF paths. The MF perturbations were of order 50% in amplitude and were not in general followed by a approximately 30-s decay toward a pre-event level, as is usually the case for the VLF signals }, keywords={ atmospheric electron precipitation ionospheric electromagnetic wave propagation radiowave propagation whistlers LF radiowave propagation ionosphere subionospheric MF whistler-induced electron precipitation bursts }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{TkalcevicDec84, author={Tkalcevic, S. and Inan, U.S. and Helliwell, R.A.}, title={ Nonlinear pitch angle scattering and trapping of energetic particles during Landau resonance interactions with whistler mode waves }, journal={Journal of Geophysical Research}, volume={89}, number={A12}, year={1984}, month={Dec}, pages={10813-26}, abstract={ The time averaged equations of motivation derived by Inan and Tkalcevic (1982) are used in a test particle study of Landau resonant interactions of whistler mode waves and energetic particles in the magnetosphere. By computing individual particle trajectories it is shown that the pitch angle scattering and energy exchange is significantly different for the two classes of particles, trapped and untrapped. The trapped particles are characterized by a bounded phase variation, whereas the nontrapped particles exhibit unbounded phase variation. The threshold wave electric field intensities necessary for trapping are determined. Full distribution test particle simulation is carried out to determine the precipitated electron flux that would be induced as a result of these interactions }, keywords={ atmospheric electron precipitation magnetosphere whistlers nonlinear trapped particle EM wave wave particle interaction pitch angle scattering trapping energetic particles Landau resonance interactions whistler mode waves equations of motivation energy exchange untrapped nontrapped }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{VossDec84, author={Voss, H.D. and Imhof, W.L. and Walt, M. and Mobilia, J. and Gaines, E.E. and Reagan, J.B. and Inan, U.S. and Helliwell, R.A. and Carpenter, D.L. and Katsufrakis, J.P. and Chang, H.C.}, title={ Lightning-induced electron precipitation }, journal={Nature}, volume={312}, number={5996}, year={1984}, month={Dec}, pages={740-2}, abstract={ The authors report the first satellite measurements of electron precipitation induced by lightning. The measured energy deposition of these conspicuous lightning-induced electron precipitation (LEP) bursts ( approximately 10/sup -3/ erg cm/sup -2/) is sufficient to deplete the Earth's radiation belts and to alter subionospheric radiowave propagation (1 the system is unstable and can generate self-excited oscillations. The self-excited oscillations reach saturation when G falls to unity, which occurs when the electron transit time through the interaction region is comparable with the phase bunching time. At signal levels well below saturation the model predicts exponential temporal growth }, keywords={ atmospheric radiation magnetosphere VLF radiowave emission triggering Doppler wave growth discrete emission magnetosphere feedback model cyclotron resonance narrowband whistler mode }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellMay82, author={Bell, T.F. and Luette, J.P. and Inan, U.S.}, title={ ISEE 1 observations of VLF line radiation in the Earth's magnetosphere }, journal={Journal of Geophysical Research}, volume={87}, number={A5}, year={1982}, month={May}, pages={3530-36}, abstract={ A search has been carried out for magnetospheric line radiation in the VLF data acquired during the period October 1977-August 1979. While the satellite position varied between L=2 and L=8 and the satellite longitude lay in the range 50 degrees W to 110 degrees W. This magnetospheric region encompassed the main regions in which the occurrence of VLF chorus has been actively linked to power line radiation. Line radiation was detected on only 5 of 90 orbits, and all examples occurred at frequencies below 4 kHz. Line radiation was detected during a period when whistler mode echoing was quite pronounced on lower L shells and may actually have been a scattered component of line radiation echoing between hemispheres on a magnetic shell of lower L value. It is concluded that very little of the background VLF wave energy in the outer magnetosphere is contained directly in VLF line radiation }, keywords={ atmospheric radiation magnetosphere radiowave emission AD 1977 to 1979 VLF line radiation magnetosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanApr82, author={Inan, U.S. and Tkalcevic, S.}, title={ Nonlinear equations of motion for Landau resonance interactions with a whistler mode wave }, journal={Journal of Geophysical Research}, volume={87}, number={A4}, year={1982}, month={Apr}, pages={2363-7}, abstract={ A simple set of equations are derived for describing the cyclotron averaged motion of Landau resonant particles in a whistler mode wave propagating at an angle to the static magnetic field. It is argued that for the parameters of the inner magnetosphere, the equations would be an accurate description of the near-resonant particles' motion. The relative magnitudes of the wave magnetic and electric field forces are discussed and the parameter ranges for which the wave magnetic field effects can be neglected are specified }, keywords={ ionosphere magnetosphere whistlers nonlinear ionosphere wave particle interaction equations of motion Landau resonance interactions whistler mode wave cyclotron inner magnetosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellOct81, author={Bell, T.F. and Inan, U.S.}, title={ Transient nonlinear pitch angle scattering of energetic electrons by coherent VLF wave packets in the magnetosphere }, journal={Journal of Geophysical Research}, volume={86}, number={A11}, year={1981}, month={Oct}, pages={9047-63}, abstract={ With the aid of adiabatic theory, a study is made of the transient nonlinear pitch angle scattering experienced by energetic electrons under the influence of coherent VLF wave packets in the magnetosphere. Finite wave packets of both fixed and variable frequency are considered, as are wide ranges of L shell, wave frequency, and wave amplitude. The results indicate that large mean pitch angle changes can be induced in the portion of the energetic population that undergoes a nonlinear cyclotron resonance interaction with the wave packet. Two classes of nonlinearly interacting particles are involved, the nonlinearly resonant particles trapped in the wave and the nonlinearly resonant nontrapped particles }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation radiowave propagation L-shell radiowave propagation energetic electrons coherent VLF wave packets magnetosphere adiabatic theory transient nonlinear pitch angle scattering wave frequency wave amplitude nonlinear cyclotron resonance interaction nonlinearly interacting particles nonlinearly resonant particles }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{BellJun81, author={Bell, T.F. and Inan, U.S. and Helliwell, R.A.}, title={ Nonducted coherent VLF waves and associated triggered emissions observed on the ISEE-1 satellite }, journal={Journal of Geophysical Research}, volume={86}, number={A6}, year={1981}, month={Jun}, pages={4649-70}, abstract={ Reports observations of non-ducted coherent VLF waves from ground-based transmitters and associated VLF emissions in the magnetosphere. The data reported were acquired by the Stanford University VLF Wave Injection Experiment on the ISEE-1 satellite. The aim is to acquire understanding of interactions between coherent VLF waves and energetic particles in the magnetosphere, in particular the whistler mode instability through which both natural and stimulated VLF emissions are produced }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation radiowave propagation radiowave propagation AD 1977 10 to 1979 10 triggered emissions non-ducted coherent VLF waves magnetosphere energetic particles whistler mode instability }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @CONFERENCE{Kimura81, author={Kimura, I. and Matsumoto, H. and Mukai, T. and Hashimoto, K. and Halliwell, R.A. and Bell, T.F. and Inan, U.S. and Katsufrakis, J.P.}, title={ EXOS/B/Siple Station VLF wave-particle interaction experiment }, booktitle={Relation Between Laboratory and Space Plasmas. Proceedings of theInternational Workshop}, volume={}, number={}, year={1981}, month={}, pages={331-8}, abstract={ It is well-known that ground-based VLF signals are often amplified or associated with VLF emissions by virtue of interactions with counterstreaming electrons in the magnetosphere. In order to clarify this mechanism of the wave-particle interaction, a Japanese satellite EXOS-B was used to monitor the energetic electron flux as well as VLF signals transmitted from Siple Station in Antarctica, expecting to observe wave excitations by the interaction between the Siple signal and the energetic electrons. The experiments were carried out in July, August, September and December 1979 and in January 1980. Telemetry data acquisition was made at NASA tracking stations locating near the Siple meridian. During these periods, VLF emissions triggered by the Siple signal were observed only in August. In the present paper, the preliminary results of experiments are briefly introduced }, keywords={ magnetosphere EM wave AD 1979 AD 1980 radiowave emission wave-particle interaction counterstreaming electrons magnetosphere energetic electron flux Siple Station Antarctica }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{KimuraDec80, author={Kimura, I. and Matsumoto, H. and Mukai, T. and Hashimoto, K. and Morikura, M. and Sasaki, C. and Helliwell, R.A. and Bell, T.F. and Inan, U.S. and Katsufrakis, J.P.}, title={ Exos-B/Siple Station wave-particle interaction experiments }, journal={Bulletin of the Institute of Space and Aeronautical Science, University ofTokyo B}, volume={16}, number={4B}, year={1980}, month={Dec}, pages={1367-80}, abstract={ In situ measurements of both energetic particles and VLF waves have been carried out in a joint program involving the Japanese satellite EXOS-B and the Siple Station VLF transmitter. A general description of the experiment is given as well as some results concerning wave-particle correlations. Telemetry data acquisition was made by NASA tracking stations during summer in 1979 and during the succeeding winter. This report describes mainly the results of the summer experiment. The Siple signal was detected on about 32% of the observed passes. Siple triggered emissions (ASE) were observed on five passes concentrated in a period from August 14 to 18, while it was geomagnetically quiet after a large magnetic storm on August 13. There were two types of Siple ASE; one is due to a direct triggering, which is normally found in the ground observation, and the other is one triggered by echoing signals, which is not usually observed on the ground }, keywords={ artificial satellites atmospheric measuring apparatus ionosphere ionospheric electromagnetic wave propagation magnetosphere magnetospheric electromagnetic wave propagation atmospheric measuring apparatus JIKIKEN satellite ionosphere EM wave propagation magnetosphere AD 1979 08 14 to 18 geomagnetic quiet period directly triggered emission telemetry data acquisition Exos-B/Siple Station wave-particle interaction experiments energetic particles VLF waves Japanese satellite Siple Station VLF transmitter wave-particle correlations NASA tracking stations Siple signal Siple triggered emissions magnetic storm echoing signals }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{YavuzAug78, author={Yavuz, D. and Inan, U.S.}, title={ A novel approach for finding the spectrum of periodically modulated FM carriers }, journal={IEEE Transactions on Communications}, volume={COM-26}, number={8}, year={1978}, month={Aug}, pages={1309-15}, abstract={ A new technique for finding the frequency spectrum of a carrier frequency modulated by a periodic signal is presented. The technique is based on the frequency modulation (FM) equation due to Hess, which in the frequency domain is a double convolution equation. The technique reduces the FM spectrum problem to the solution of a set of linear equations in which the FM side-band amplitudes are the unknowns. The technique is simple and as a result its implementation on a standard computer is both simple and fast. Furthermore, it is especially suitable when the modulating signal is in the form of a Fourier series with a large number of terms or requires a large number of terms to approximate it. Numerical results obtained using the technique for a large number of complex modulating signals are presented }, keywords={ frequency modulation signal processing periodically modulated FM carriers frequency spectrum double convolution equation }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanJul78, author={Inan, U.S. and Bell, T.F. and Helliwell, R.A.}, title={ Nonlinear pitch angle scattering of energetic electrons by coherent VLF waves in the magnetosphere }, journal={Journal of Geophysical Research}, volume={83}, number={A7}, year={1978}, month={Jul}, pages={3235-53}, abstract={ A computer simulation approach is used to study the nonlinear cyclotron resonant interaction of energetic electrons and coherent VLF waves, with special emphasis on the pitch angle scattering of the particles. Complete equations of motion in an inhomogeneous magnetosphere are used, and the effects of various parameters are studied. Comparison is made with linear theory, and a quantitative and easy-to-use criterion to determine the applicability of linear theory under any given conditions is presented. The full distribution of particles is simulated by test electrons appropriately distributed in energy and pitch angle. By computing the scattering of these test particles and integrating over energy and pitch angle, the precipitated flux is obtained. The results indicate that coherent VLF waves can have a significant effect on the dynamics and lifetimes of energetic electrons trapped in the magnetosphere on magnetic shells illuminated by the waves }, keywords={ atmospheric electron precipitation atmospheric radiation magnetosphere magnetospheric electromagnetic wave propagation whistlers energetic electrons coherent VLF waves magnetosphere computer simulation nonlinear cyclotron resonant interaction pitch angle scattering linear theory applicability criterion 1 to 2 keV electrons precipitated particle flux whistler mode waves wave/particle interactions particle energy integration }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanJul77, author={Inan, U.S. and Bell, T.F.}, title={ The plasmapause as a VLF wave guide }, journal={Journal of Geophysical Research}, volume={82}, number={19}, year={1977}, month={Jul}, pages={2819-27}, abstract={ The properties of the plasmapause as a VLF wave guide are studied. The guidance that occurs is a form of gradient trapping of VLF wave energy. It is shown that guiding is possible at both the inner and outer edges of the plasmapause and that more efficient guiding occurs as the plasmapause gradients become stronger. In the case of strong gradients, waves coming from a wide latitude range ( approximately 8 degrees ) are focused tightly about the plasmapause field lines, resulting in a wave intensity increase of approximately 3 dB near the magnetic equatorial plane. It is shown that plasmapause-guided waves can be observed on the ground and can echo between hemispheres, precisely as can waves guided in normal whistler ducts. The single distinguishing feature of plasmapause-guided waves is a lowered upper cutoff frequency. The results indicate that the vicinity of the plasmapause represents a natural and readily accessible region of VLF wave guidance and focusing where both passive and active VLF experiments can be studied through ground and in situ satellite measurements }, keywords={ guided electromagnetic wave propagation magnetospheric electromagnetic wave propagation radiowave propagation plasmapause VLF wave guide whistler mode waves }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.28355 @ARTICLE{InanMar77, author={Inan, U.S. and Bell, T.F. and Carpenter, D.L. and Anderson, R.R.}, title={ Explorer 45 and Imp 6 observations in the magnetosphere of injected waves from the Siple Station VLF transmitter }, journal={Journal of Geophysical Research}, volume={82}, number={7}, year={1977}, month={Mar}, pages={1177-87}, abstract={ Reports the first results of a Stanford University-University of Iowa joint experiment in which VLF waves from the Siple Station transmitter in Antarctica are injected into the magnetosphere along the Earth's magnetic field lines and are detected near the magnetic equatorial plane by the Explorer 45 and Imp 6 spacecraft. The purpose of this experiment is to conduct a controlled in situ study of VLF wave-particle interactions, in particular, to determine the propagation characteristics of the injected waves in the magnetosphere, to determine the regions where VLF emissions are produced, and to determine the effective volume of the magnetosphere illuminated by the Siple transmitter }, keywords={ magnetosphere magnetospheric electromagnetic wave propagation radiowave propagation Explorer 45 Imp 6 magnetosphere injected waves Siple Station VLF transmitter Antarctica wave particle interactions }, mynotes={UNREAD}, } @ARTICLE{InanMar77, author={Inan, U.S. and Bell, T.F. and Anderson, R.R.}, title={ Cold plasma diagnostics using satellite measurements of VLF signals from ground transmitters }, journal={Journal of Geophysical Research}, volume={82}, number={7}, year={1977}, month={Mar}, pages={1167-76}, abstract={ A new diagnostic technique to obtain the cold plasma density profile in the magnetosphere is introduced. This method uses satellite measurements of group delay and pulse duration of VLF signals from ground transmitters in conjunction with a detailed ray tracing analysis. An iterative method is involved. This method starts with an approximate density profile, computes the ray paths for that profile, and then compares the properties of the rays that reach the satellite location with the actual satellite measurements. The density profile is then modified to account for any discrepancies between the two results. The same process is repeated with the new profile until one has reasonable agreement between the data and ray tracing results. This method is applied to the case of an Imp 6 pass on June 28, 1973, where strong signals from the Siple VLF transmitter were observed for over 25 min. Good agreement is found between the results of the new technique and the well-known ground whistler techniques of cold plasma diagnostics. The results also serve to illustrate the wide diversity of paths of propagation from ground transmitters to high-altitude satellites during VLF wave injection experiments }, keywords={ atmospheric techniques magnetosphere magnetospheric electromagnetic wave propagation plasma plasma diagnostics satellite measurements VLF signals ground transmitters diagnostic technique cold plasma density profile magnetosphere ray tracing iterative method }, mynotes={UNREAD}, }