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Electrical and Computer Engineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
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- Field effect transistors (2)
- Heterojunctions (2)
- Hot carriers (2)
- Balanced truncation (1)
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- Biomedical (1)
- Controllability and observability gramians (1)
- Cyberterrorism (1)
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- MAP estimation (1)
- MODFETs (1)
- Model reduction (1)
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- Multispectral (1)
- PDA mobile video telementoring endoscopic (1)
- Panchromatic Sharpening (1)
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Articles 1 - 9 of 9
Full-Text Articles in Electrical and Computer Engineering
Simulation Of Gate Lag And Current Collapse In Gallium Nitride Field-Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, M. S. Shur, M. Asif Khan, Grigory Simin
Simulation Of Gate Lag And Current Collapse In Gallium Nitride Field-Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, M. S. Shur, M. Asif Khan, Grigory Simin
Faculty Publications
Results of two-dimensional numerical simulations of gate lag and current collapse in GaN heterostructurefield-effect transistors are presented. Simulation results clearly show that current collapse takes place only if an enhanced trapping occurs under the gate edges. Hot electrons play an instrumental role in the collapse mechanism. The simulation results also link the current collapse with electrons spreading into the buffer layer and confirm that a better electron localization (as in a double heterostructurefield-effect transistor) can dramatically reduce current collapse.
Establishing A Cyber Warrior Force, Scott D. Tobin
Establishing A Cyber Warrior Force, Scott D. Tobin
Theses and Dissertations
Cyber Warfare is widely touted to be the next generation of warfare. As America's reliance on automated systems and information technology increases, so too does the potential vulnerability to cyber attack. Nation and non-nation states are developing the capability to wage cyber warfare. Historically, the Air Force and DoD have concentrated their efforts toward defensive network operations. However, a shift in doctrine has shown both the Air Force and DoD acknowledging the potential for Information Warfare. What appears to be lacking is the trained and educated cyber warrior force that will carry out the information operations if needed. This research …
Map Estimation For Hyperspectral Image Resolution Enhancement Using An Auxiliary Sensor, Russell C. Hardie, Michael T. Eismann, Gregory L. Wilson
Map Estimation For Hyperspectral Image Resolution Enhancement Using An Auxiliary Sensor, Russell C. Hardie, Michael T. Eismann, Gregory L. Wilson
Electrical and Computer Engineering Faculty Publications
This paper presents a novel maximum a posteriori (MAP) estimator for enhancing the spatial resolution of an image using co-registered high spatial-resolution imagery from an auxiliary sensor. Here we focus on the use of high-resolution panchomatic data to enhance hyperspectral imagery. However, the estimation framework developed allows for any number of spectral bands in the primary and auxiliary image. The proposed technique is suitable for applications where some correlation, either localized or global, exists between the auxiliary image and the image being enhanced. To exploit localized correlations, a spatially varying statistical model, based on vector quantization, is used. Another important …
Volume Holographic Recording And Readout For 90-Deg Geometry, Partha P. Banerjee, Monish Ranjan Chatterjee, Nickolai Kukhtarev, Tatiana Kukhtareva
Volume Holographic Recording And Readout For 90-Deg Geometry, Partha P. Banerjee, Monish Ranjan Chatterjee, Nickolai Kukhtarev, Tatiana Kukhtareva
Electrical and Computer Engineering Faculty Publications
When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type diffracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function approach based on 2-D Laplace transforms. In a second series of investigations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various dependences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the …
Volume Holographic Optical Elements, Ching-Cherng Sun, Partha P. Banerjee
Volume Holographic Optical Elements, Ching-Cherng Sun, Partha P. Banerjee
Electrical and Computer Engineering Faculty Publications
The final two papers are concerned with the analysis of novel holograms. Banerjee et al. investigate holographic recording and reconstruction for edge-lit holograms recorded in a 90-degree geometry. Various cases of recording and readout that incorporate propagational diffraction have been modeled. It is shown that the 90-degree geometry can result in beam shaping, as evidenced through preliminary experimental results with photorefractive lithium niobate. Nguyen et al. propose a new approach for designing computer-generated holograms. An artificial neural network is used to initiate the genetic algorithm so that the high computation cost of genetic algorithms for synthesizing holograms is significantly reduced …
Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang
Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang
Faculty Publications
We report on simulations of electrical characteristics of AlGaN/(InGaN)/GaN heterostructurefield effect transistors with quantum and hot electroneffects taken into account. Polarization charges lead to quantum confinement of electrons in the channel and to the formation of two-dimensional electron gas. The electron quantization leads to the spread of the electronwave function into the barrier and bulk but does not have significant impact on dc electrical characteristics.Hot electrons play an important part in the charge transport by spilling over into the bulk GaN where they are captured by traps. This leads to negative differential conductivity, which is also observed experimentally. The simulation …
Parameter Extraction Software For Silicon Carbide Schottky, Merged Pin Schottky And Pin Power Diode Models, Edgar Cilio
Parameter Extraction Software For Silicon Carbide Schottky, Merged Pin Schottky And Pin Power Diode Models, Edgar Cilio
Inquiry: The University of Arkansas Undergraduate Research Journal
A software program for on-state parameter extraction is presented for the realization of a high quality model for SiC Schottky, Merged PiN Schottky, and PiN Power diodes based on McNutt and Mantooth's Comprehensive SiC Diode model [ 1 ].
The Personal Digital Assistant (Pda) As A Tool For Telementoring Endoscopic Procedures., Cody K. Bumgardner
The Personal Digital Assistant (Pda) As A Tool For Telementoring Endoscopic Procedures., Cody K. Bumgardner
Cody Bumgardner
Abstract: The telementoring of surgical procedures is currently achieved via a wired infrastructure that usually requires sophisticated videoconference systems. This project represents the first step in assessing the potential for using handheld computers as a mobile alternative to current telementoring systems. Specifically, this project compares a handheld computer to a standard CRT monitor regarding their capability to accurately display video images from an endoscopic procedure. Video images from two previously recorded endoscopic procedures were transmitted from a standard VCR to: 1) a handheld computer (iPAQ 3670 running Pocket PC) via a wireless LAN and 2) a standard CRT monitor via …
On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov
On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov
Articles
Novel constructions of empirical controllability and observability gramians for nonlinear systems for subsequent use in a balanced truncation style of model reduction are proposed. The new gramians are based on a generalisation of the fundamental solution for a Linear Time-Varying system. Relationships between the given gramians for nonlinear systems and the standard gramians for both Linear Time-Invariant and Linear Time-Varying systems are established as well as relationships to prior constructions proposed for empirical gramians. Application of the new gramians is illustrated through a sample test-system.