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Filters: School Or College: "College of Engineering" Department: "Electrical & Computer Engineering" Collection: "ir_uspace"
126 - 150 of 577
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CreatorTitleDescriptionSubjectDate
126 Furse, Cynthia M.; Gandhi, Om P.Computations of SAR distributions for two anatomically-based models of the human head using CAD files of commercial telephones and the parallelized FDTD codeThe Finite Difference Time Domain (FDTD) method is well suited for the computation of bio-electromagnetic effects and has become the method of choice for most researchers in this area. There does however remain some limitations on its use. Firstly the FDTD method requires large amounts of memory and...Finite-difference time-domain method; FDTD; SAR distributions; CAD files1997
127 Myers, Chris J.An asynchronous implementations of the MAXLIST algorithmABSTRACT We present an efficient asynchronous VLSI architecture for calculating running maximum or minimum values over a sliding window. Running maximums or minimums are very useful for many signal and image processing tasks. Our architecture performs the calculation using the MAXLIST algorithm. In...1997
128 Mathews, V. JohnPerceptually lossless image compressionThere are many instances in which human observers are the final judges of the quality of a compressed image. In such situations, it is useful to incorporate a model of the human visual system (HVS) into the image compression system in order to reduce or even eliminate the visual distortions introdu...1997
129 Stringfellow, Gerald B.Effects of V/III ratio on ordering and antiphase boundaries in GaInP layersTransmission electron microscope (TEM) and transmission electron diffraction (TED) studies have been performed to investigate the effects of V/III ratio on ordering and antiphase boundaries (APBs) in organometallic vapor phase epitaxial Ga0.5In0.5P layers grown onto (001) GaAs vicinal substrates ...Antiphase boundaries; APB; Heterostructures; Organometallics1997
130 Stringfellow, Gerald B.Order and surface processes in III-V semiconductor alloysSemiconductor alloys have become increasingly useful during the last four decades because, through the use of alloys, the properties of semiconductors can be tailored by varying the composition to precisely match the requirements for specific electronic and photonic devices.Semiconductor alloys; Transmission-electron-diffraction pattern; Organometallic Vaper-phase epitaxy1997
131 Myers, Chris J.Efficient timing analysis algorithms for timed state space exploration*Abstract This paper presents new timing analysis algorithms for efficient state space exploration during timed circuit synthesis. Timed circuits are a class of asynchronous circuits that incorporate explicit timing information in the specification which is used throughout the synthesis procedure t...1997
132 Mathews, V. JohnVector quantization using the L∞ distortion measureAbstract-This paper considers vector quantization of signals using the L1 distortion measure. The key contribution is a result that allows one to characterize the centroid of a set of vectors for the L1 distortion measure. A method similar to the Linde-Buzo-Gray (LBG) algorithm for designing codeboo...1997
133 Mathews, V. JohnOn the inversion of certain nonlinear systemsAbstract-In this letter, we present some theorems for the exact inversion and the pth-order inversion of a wide class of causal, discrete-time, nonlinear systems. The nonlinear systems we consider are described by the input-output relationship y(n) = g[x(n)]h[x(n - 1); y(n - 1)]+f[x(n - 1); y(n - 1)...1997
134 Stringfellow, Gerald B.Effect of growth rate on step structure and ordering in GaInPCuPt ordering is widely observed in GaInP epitaxial layers grown by organometallic vapor phase epitaxy. The formation of this spontaneously ordered structure during epitaxial growth is intimately related to the atomic-scale physical processes occurring on the surface, specifically surface reconst...Atomic force microscopy; Organometallic vapor phase; Crystallographic plane1997
135 Stringfellow, Gerald B.;Inglefield, Colin E.;Taylor, P. CraigCharacterization of unicompositional GaInP2 ordering heterostructures grown by variation of V/III ratioPhotoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies are employed to investigate single heterostructures based on two GaInP2 layers that have the same composition but different degrees of order on the cation sublattice. Four sample configurations are studied: two complemen...Heterostructures; Growth parameters; Growth temperature1997
136 Stringfellow, Gerald B.Compositional modulation and ordering in semiconductorsThe science of materials as a specific discipline is a relatively modern development. Within this rather modern field, the study of semiconductor materials is an even more recent development. Modern textbooks on materials science focus primarily on the properties of metals and second on the properti...Materials scientists; Controlled ordering1997
137 Mathews, V. JohnAdaptive unsharp masking for contrast enhancementABSTRACT A new scheme o,f unsharp masking for image contrast enhancement is presented in this paper. An adaptive algorithm is introduced so that a sharpening action is performed only in locations where the image exhibits significant dynamics. Hence, the amplification of noise in smooth areas i...1997
138 Tasdizen, TolgaPIMs and invariant parts for shape recognitionWe present completely new very powerful solutions t o two fundamental problems central to computer vision. 1. Given data sets representing C objects to be stored in a database, and given a new data set for an object, determine the object in the database that is most like the object measured. We so...1997
139 Myers, Chris J.Synthesis of timed circuits using BDDs*This paper presents a tool which synthesizes timed circuits from reduced state graphs. Using timing information to reduce state graphs can lead to significantly smaller and faster circuits. The tool uses implicit techniques (binary decision diagrams) to represent these graphs. This allows us to synt...1997
140 Mathews, V. John; Schlegel, ChristianComputationally efficient multiuser detection for coded CDMAAbstract: Computationally efficient multiuser detection for coded asynchronous CDMA systems is investigated. The particular receiver studied is a near-far resistant multi-user detector known as the projection receiver (PR) [originally developed in [1, 2]]. The PR perfoms multiple access interference...1997
141 Furse, Cynthia M.; Gandhi, Om P.Currents induced in the human body for exposure to ultrawideband electromagnetic pulsesThe frequency-dependent finite-difference time-domain [(FD)2TD] method is used to calculate internal electric fields and induced current densities in a 1.31-cm resolution anatomically-based model of the human body for exposure to ultrawideband vertically polarized electromagnetic pulses (EMP's). Fr...FDTD; Finite-difference time-domain; Ultrawideband electromagnetic pulses; Induced currents1997-01-01
142 Mathews, V. JohnOn the inversion of certain nonlinear systemsIn this letter, we present some theorems for the exact inversion and the pth-order inversion of a wide class of causal, discrete-time, nonlinear systems. The nonlinear systems we consider are described by the input-output relationship y(n) = g[x(n)]h[x(n-1); (n-1)]+f[x(n-1); y(n-1)], here g[], h[; ]...1997-01-01
143 Stringfellow, Gerald B.Heterostructures in GaInP grown using a change in V/III ratioA natural monolayer 111% superlattice -- the CuPt ordered structure -- is formed spontaneously during organometallic vapor phase epitaxial OMVPE growth of Ga0.52In0.48P. The extent of this ordering process is found to be a strong function of the input partial pressure of the phosphorus precursor dur...Superlattices; Alloys; Atomic ordering; Heterostructures1997-02-24
144 Stevens, KennethA mathematical approach to a low power FFT architectureArchitecture and circuit design are the two most effective means of reducing power in CMOS VLSI. Mathematical manipulations have been applied to create a power efficient architecture of an FFT. This architecture has been implemented in asynchronous circuit technology that achieves significant powe...1998
145 Mathews, V. John; Schlegel, ChristianA blind adaptive projection receiver for CDMA systemsAbstract - This paper presents a blind and adaptive CDMA receiver that does not require knowledge of the spreading codes associated with users other than the ones of interest. Receivers for synchronous as well as asynchronous transmission by multiple users with error control coding are develope...1998
146 Stringfellow, Gerald B.Influence of tellurium doping on step bunching of GaAs (001) vicinal surfaces grown by organometallic vapor phase epitaxyAtomic force microscopy has been used to investigate the influence of controlled tellurium Te incorporation on the step structure of GaAs grown by organometallic vapor phase epitaxy on vicinal 001 surfaces. Te doping, using the precursor diethyltelluride, is found to markedly decrease the surface r...Epitaxial growth; Misorientation; Organometallic vapor phase epitaxy1998
147 Mathews, V. JohnAn analytical model of the perceptual threshold function for multichannel image compressionABSTRACT The human observer is often the final judge of the quality of compressed images. One way to design a compression system that attempts to reduce or eliminate subjective distortions in the coded images is to incorporate a perceptual threshold function model into the compression system. The...1998
148 Stringfellow, Gerald B.Step structure and ordering in GaInPPresents information from an experiment on the step structure and ordering in GalnP. Information on the step spacing and degree of order in the epitaxial layers; Details on the experiment; Results from the experiment.Physics; Ordering; Steps1998
149 Furse, Cynthia M.Faster than fourier -- ultra-efficient time-to-frequency domain conversions for FDTDTwo highly efficient methods of computing magnitude and phase from time-domain data are demonstrated. These methods, based on solution of linear equations, are found to be equally accurate and more efficient than Fourier transform methods (DIT and FFT) for limited numbers of Frequencies. These metho...Finite-difference time-domain method; FDTD; Fourier transform methods; Sine wave magnitude; Sine wave phase1998
150 Stringfellow, Gerald B.Step structure and ordering in Te-doped GaInPThe step structure and CuPt ordering in GaInP layers grown by organometallic vapor phase epitaxy on singular GaAs substrates have been investigated as a function of Te (DETe) doping using atomic force microscopy, and electrical and optical properties measurements. The degree of order decreases for T...Surfaces; Te doping; Bandgap energy1998
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