Engineering Commons^™

A New Control Strategy For The Unified Power Flow Controller, Lin Zhang, Liangying Dong, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The unified power flow controller (UPFC) is the most versatile among a variety of flexible AC transmission system (FACTS) devices, which can be used for power flow control, enhancement of transient stability, damping system oscillations and voltage regulation. In this paper, we propose a new PI based approach for the dynamic control of UPFC. With the new control strategy, not only the active and reactive power flow control but also the system oscillations damping can be achieved. The digital simulation results developed in MATLAB and PSCAD/EMTDC environments are presented to verify the efficiency of the proposed control algorithm.

Reducing Power Bus Impedance At Resonance With Lossy Components, Todd H. Hubing, Theodore M. Zeeff

Electrical and Computer Engineering Faculty Research & Creative Works

Power bus structures in printed circuit boards with solid power and ground planes exhibit resonances. When the power bus is resonant, the power bus impedance can increase dramatically. This paper explores the effect of component equivalent series resistance (ESR) on power bus resonances. General guidelines for selecting an optimum ESR are provided and are supported by laboratory measurements and numerical simulations.

Restoration Of The Lorentzian And Debye Curves Of Dielectrics And Magnetics For Fdtd Modeling, Marina Koledintseva, Konstantin Rozanov, James L. Drewniak, Gabriele Di Fazio

Electrical and Computer Engineering Faculty Research & Creative Works

The algorithms of extracting the Lorentzianand Debye-curve parameters of dielectric and magnetic materials from the results of measurements at several frequency points are presented. These algorithms are based on an analytical solution of systems of non-linear equations with physical constraints that follow from the fundamental principle of causality. The extracted parameters are useful for FDTD modeling of electromagnetic structures containing such dispersive media. Some examples are presented.

Speedup Of Self-Timed Digital Systems Using Early Completion, Scott C. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

An Early Completion technique is developed to significantly increase the throughput of NULL Convention self-timed digital systems without impacting latency or compromising their self-timed nature. Early Completion performs the completion detection for registration stage i at the input of the register, instead of at the output of the register as in standard NULL Convention Logic. This method requires that the single-rail completion signal from registration stage i+1 , Ko i+1 , be used as an additional input to the completion detection circuitry for registration stage i , to maintain self-timed operation. However, Early Completion does necessitate an assumption of equipotential …

Electron Pulse Broadening Due To Space Charge Effects In A Photoelectron Gun For Electron Diffraction And Streak Camera Systems, Bao-Liang Qian, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The electron pulse broadening and energy spread, caused by space charge effects, in a photoelectron gun are studied analytically using a fluid model. The model is applicable in both the photocathode-to-mesh region and the postanode electron drift region. It is found that space charge effects in the photocathode-to-mesh region are generally unimportant even for subpicosecond pulses. However, because of the long drift distance, electron pulse broadening due to space charge effects in the drift region is usually significant and could be much larger than the initial electron pulse duration for a subpicosecond electron pulse. Space charge effects can also lead …

Atomic Hydrogen Cleaning Of Inp(100): Electron Yield And Surface Morphology Of Negative Electron Affinity Activated Surfaces, M. A. Hafez, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Atomic hydrogen cleaning of the InP(100) surface has been investigated using quantitative reflection high-energy electron diffraction. The quantum efficiency of the surface when activated to negative electron affinity was correlated with surface morphology. The electron diffraction patterns showed that hydrogen cleaning is effective in removing surface contaminants, leaving a clean, ordered, and (2×4)-reconstructed surface. After activation to negative electron affinity, a quantum efficiency of ∼6% was produced in response to photoactivation at 632 nm. Secondary electron emission from the hydrogen-cleaned InP(100)-(2×4) surface was measured and correlated to the quantum efficiency. The morphology of the vicinal InP(100) surface was investigated using …

Acceleration Element For Femtosecond Electron Pulse Compression, Bao-Liang Qian, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

An acceleration element is proposed for compressing the electron pulse duration in a femtosecond photoelectron gun. The element is a compact metal cavity with curved-shaped walls. An external voltage is applied to the cavity where a special electric field forms in such a way that the slow electrons in the electron pulse front are accelerated more than the fast electrons, and consequently the electron pulse duration will be compressed. The distribution of the electric field inside the acceleration cavity is analyzed for the geometry of the cavity. The electron dynamics in this acceleration cavity is also investigated numerically. Numerical results …

High-Efficiency Solar Cells Based On Cu(Inal)Se[Sub 2] Thin Films, S. Marsillac, P. D. Paulson, M. W. Haimbodi, R. W. Birkmire, W. N. Shafarman

Electrical & Computer Engineering Faculty Publications

A Cu(InAl)Se₂solar cell with 16.9% efficiency is demonstrated using a Cu(InAl)Se₂thin film deposited by four-source elemental evaporation and a device structure of glass/Mo/Cu(InAl)Se₂/CdS/ZnO/indium tin oxide/(Ni/Algrid)/MgF₂. A key to high efficiency is improved adhesion between the Cu(InAl)Se₂ and the Mo back contact layer, provided by a 5-nm-thick Ga interlayer, which enabled the Cu(InAl)Se₂ to be deposited at a 530 °C substrate temperature. Film and device properties are compared to Cu(InGa)Se₂ with the same band gap of 1.16 eV. The solar cells have similar behavior, with performance limited by recombination through …

Generalized Inclusive Forms — New Canonical Reed-Muller Forms Including Minimum Esops, Marek Perkowski, Alan Mishchenko, Malgorzata Chzanowka-Jeske

Electrical and Computer Engineering Faculty Publications and Presentations

Reed-Muller (AND/EXOR) expansions play an important role in logic synthesis and circuit design by producing economical and highly-testable implementations of Boolean functions [3–6]. The range of Reed-Muller expansions include canonical forms, i.e. expansions that create unique representations of a Boolean function. Several large families of canonical forms: fixed polarity Reed-Muller forms (FPRMs), generalized Reed-Muller forms (GRMs), Kronecker forms (KROs), and pseudo- Kronecker forms (PKROs), referred to as the Green/Sasao hierarchy, have been described [7–9]. (See Fig. 1 for a settheoretic relationship between these families.)

Term Trees In Application To An Effective And Efficient Atpg For And–Exor And And–Or Circuits, Lech Jozwiak, Aleksander Ślusarczyk, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

A compact data representation, in which the typically required operations are performed rapidly, and effective and efficient algorithms that work on these representations are the essential elements of a successful CAD tool. The objective of this paper is to present a new data representation—term trees (TTs)—and to discuss its application for an effective and efficient structural automatic test-pattern generation (ATPG). Term trees are decision diagrams similar to BDDs that are particularly suitable for structure representation of AND–OR and AND–EXOR circuits. In the paper, a flexible algorithm for minimum term-tree construction is discussed and an effective and efficient algorithm for ATPG …

Multiple-Valued Quantum Logic Synthesis, Marek Perkowski, Anas Al-Rabadi, Pawel Kerttopf

Electrical and Computer Engineering Faculty Publications and Presentations

This paper asks the question: is logic synthesis for quantum computers a practical research subject?

We would like to assume that any two quantum wires can interact, but we are limited by the realization constraints. Structure of atomic bonds in the molecule determines neighborhoods in the circuit. This is similar to restricted routing in FPGA layout - link between logic and layout synthesis known from CMOS design now appears in quantum. Below we are interested only in the so-called “permutation circuits” - their unitary quantum matrices are permutation matrices.

New Architecture For Heterogeneous Real-Time Simulation, Mandar Anil Mathure

Retrospective Theses and Dissertations

This thesis investigates a new architecture for modeling and simulating complex distributed real-time systems. Modeling adequately a large distributed real time system may involve, due to its complexity, several different theoretical vehicles such as queuing theory, finite state machines, and others. Currently there are no software tools, which would offer combining such heterogeneous features into a single comprehensive simulation environment.

This study involves integrating 3 tools, SES/workbench, an offline simulator using queuing theory as its modeling discipline, ObjecTime as a real-time simulator based on finite state machines as its modeling discipline, and VxWorks real-time kernel used for free modeling in …

Wavelength Assignment In All-Optical Networks For Mesh Topologies, Prabhulaiah Bijja

LSU Master's Theses

All-Optical Networks employing Dense Wavelength Division Multiplexing (DWDM) are believed to be the next generation networks that can meet the ever-increasing demand for bandwidth of the end users. This thesis presents some new heuristics for wavelength assignment and converter placement in mesh topologies. Our heuristics try to assign the wavelengths in an efficient manner that results in very low blocking probability. We propose novel static and dynamic assignment schemes that outperform the assignments reported in the literature even when converters are used. The proposed on-line scheme called "Round-Robin" assignment outperforms previously proposed strategies such as first-fit and random assignment schemes. …

Modulation Classification Of Digital Communication Signals, Visalakshi S. Ramakonar

Theses: Doctorates and Masters

Modulation classification of digital communications signals plays an important role in both military and civilian sectors. It has the potential of replacing several receivers with one universal receiver. An automatic modulation classifier can be defined as a system that automatically identifies the modulation type of the received signal given that the signal exists and its parameters lie in a known range. This thesis addresses the need for a universal modulation classifier capable of classifying a comprehensive list of digital modulation schemes. Two classification approaches are presented: a decision-theoretic (DT) approach and a neural network (NN) approach. First classifiers are introduced …

Mobile Home Security With Gprs, Duy Nguyen

Theses : Honours

This thesis presents the results of an honours project on the development of a security system for use on mobile devices. Mobile Home Security (MHS) is a prototype system that aimed to fully investigate a potential use of the wireless high-speed technology General Packet Radio Service (GPRS) in transmitting video from a static location. This thesis Mobile Home Security with GPRS describes in detail the design and developmental stages for the system. The research focused on the sending of video from a security capture device over a high speed radio network. The first stage of the research involved the design …

Design And Analysis Of Optical Layouts For Free Space Optical Switching, Kung-Meng Lo

Theses: Doctorates and Masters

The Intelligent Reconfigurable Optical Switch (IROS) is an N x N optical switch that uses two reflective Liquid Crystal (LC) Spatial Light Modulators (SLM} in a "Z" configuration to steer the incoming beams from the input ports to the designated output ports. Currently, the maximum steering capacity of practical SLM is limited to few degrees. For a dense optical switch, this makes the optical path between the input and output fiber ports relatively long. When a Gaussian beam is switched from an input fiber port to an output fiber port in a long free space interconnection topology, the beam's illumination …

Video Indexing And Retrieval Techniques Using Novel Approaches To Video Segmentation, Characterization, And Similarity Matching, Waleed Ezzat Farag

Computer Science Theses & Dissertations

Multimedia applications are rapidly spread at an ever-increasing rate introducing a number of challenging problems at the hands of the research community, The most significant and influential problem, among them, is the effective access to stored data. In spite of the popularity of keyword-based search technique in alphanumeric databases, it is inadequate for use with multimedia data due to their unstructured nature. On the other hand, a number of content-based access techniques have been developed in the context of image indexing and retrieval; meanwhile video retrieval systems start to gain wide attention, This work proposes a number of techniques constituting …

Deconvolution Of Compartmental Water Diffusion Coefficients In Yeast-Cell Suspensions Using Combined T1 And Diffusion Measurements, Matthew D. Silva, Karl G. Helmer, Jing-Huei Lee, Sam S. Han, Charles S. Springer, Christopher H. Sotak

Sam Han

Deconvolution of Compartmental Water Diffusion Coefficients in Yeast-Cell Suspensions Using Combined T1 and Diffusion Measurements