Digital Commons Network^™

Organizational Change, Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Xenon Excimer Emission From Pulsed Microhollow Cathode Discharges, M. Moselhy, R. H. Stark, K. H. Schoenbach, U. Kogelschatz

Bioelectrics Publications

By applying electrical pulses of 20 ns duration to xenon microplasmas, generated by direct current microhollow cathode discharges, we were able to increase the xenon excimer emission by more than an order of magnitude over direct current discharge excimer emission. For pulsed voltages in excess of 500 V, the optical power at 172 nm was found to increase exponentially with voltage. Largest values obtained were 2.75 W of vacuum-ultraviolet optical power emitted from a single microhollow cathode discharge in 400 Torr xenon with a 750 V pulse applied to a discharge. Highest radiative emittance was 15.2 W/cm². The …

Atm Lane Simulator, Kim Joo Ching

Student Works (2000-2009)

This project describes the development of ATM Local Area Network Emulation (LANE) simulator components. In LANE, an A TM network is configured to simulate an Ethernet or token ring network and coexist with the legacy network without making any modification to Them.The development of this simulator incorporates several important features. The most important feature of the simulator is that it is build based on object-oriented approach, which is able to provide the benefits of re usability, flexibility and extensibility. The second important feature is that it supports multi threaded operations. This means that every object able to act simultaneously. Besides …

Simulating Quasi-Ballistic Transport In Si Nanotransistors, Kausar Banoo, Jung-Hoon Rhew, Mark S. Lundstrom, Chi-Wang Shu, Joseph W. Jerome

Department of Electrical and Computer Engineering Faculty Publications

Electron transport in model Si nanotransistors is examined by numerical simulation using a hierarchy of simulation methods, from full Boltzmann, to hydrodynamic, energy transport, and drift-diffusion. The on-current of a MOSFET is shown to be limited by transport across a low-field region about one mean-free-path long and located at the beginning of the channel. Commonly used transport models based on simplified solutions of the Boltzmann equation are shown to fail under such conditions. The cause for this failure is related to the neglect of the carriers' drift energy and to the collision-dominated assumptions typically used in the development of simplified …

Uniform Random Number Generation Using Pseudorandom Binary Sequences, Susan Rea

Theses

Random numbers have conventionally been used in a range of applications such as numerical analysis, lotteries and computer simulation and as cryptographic keys. The algorithms used for the production of random numbers are termed pseudorandom, as the numbers produced are not truly random as they emanate from a deterministic periodic source that is they are predictable if a subset of the sequence is known. However, for most applications these pseudorandom number sources are entirely suitable.

For cryptographic key sources, however, the random number sequences must be statistically good and difficult to predict. Linear feedback shift registers are presented in this …

Analysis Of A Four-Level Dc/Dc Buck Converter, Keith Corzine, J. Yuen, J. R. Baker

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a four-level DC/DC buck converter is introduced. The primary application for this converter is to regulate the center capacitor voltage in a four-level inverter system. The steady-state and average-value models for the proposed converter are developed and compared in simulation. The converter was constructed in the laboratory and verified on a four-level motor drive system. It was shown that the four-level DC/DC converter provides capacitor voltage balancing and allows higher output voltage utilization from the inverter.

Simulation Study And Instability Of Adaptive Control, Zhongshan Wu

LSU Master's Theses

The Minimum-degree Pole Placement algorithm for Self-tuning Regulator design and the Recursive Least-square method and the projection algorithm for plant estimation are studied first in this thesis. Simulation studies for the estimator and controller algorithms are mainly undertaken after describing how to use MATLAB S-function in detail. Not only do Simulation experiments illustrates how and how well the MDPP and RLS algorithms work, but also show how to write and debug MATLAB codes for S-function programs. The robustness of the adaptive control system is intensively discussed subsequently. By using an estimator resistant to the noise contamination, the adaptive control system …

Keyboard - Smart Card Reader Controller Using Vhdl, Lani Mohd Zuwairi

Student Works (2000-2009)

As the time fly by the technology of computers has improves and much security is needed in every transaction of data that being done. In this project, designing a microcontroller for keyboard and smart card reader terminal integration is being done. At first stage, the architecture of the controller will analyze and studied. This will need some practice of knowledge in computer organization and architecture, as well as microprocessors architecture designs. Then the architecture is design using hardware prototyping. This is by using the VHSIC Hardware Description Language (VHDL). The codes done using the language then being simulate to get …

Development Of Object-Oriented Components For Atm Network Simulation With Emphasis On Congestion Control, Wai Kit Sin

Student Works (2000-2009)

Asynchronous Transfer Mode (ATM) is a very high-speed transmission technology. The barrage of technological advancements has continuously enhanced the network performance. There is an increasing dependence on the network. Thus, there is a need to accurately predict the impact of network and applications changes in the dynamic network environment. The network simulator is a tool to analyze the behavior of ATM networks without the expense of building a real network. The simulation of this simulator will give the results that imitate the real network environment. The aim of this project is to develop object-oriented components for an ATM Network Simulator …

Accurate Parameter Estimation For An Articulatory Speech Synthesizer With An Improved Neural Network Mapping, Hali̇s Altun, Tankut Yalçinöz, K. Mervyn Curtis

Turkish Journal of Electrical Engineering and Computer Sciences

Neural network (NN) applications have recently been employed to extract the parameters of an articulatory speech synthesizer from a given speech signal. Results from these attempts showed that a single NN is insufficient to cover all of the possible configurations uniquely. Moreover, apart from their computational advantages, NN mapping is so far not superior to the other mapping techniques [1]. Thus there is a clear need to improve NN solution to the inverse problem. Results from our earlier experiments with an articulatory speech synthesizer have shown that the statistical characteristic of the articulatory target pattern vectors can be exploited for …

Scalar Wave Diffraction By A Perfectly Soft Infinitely Thin Circular Ring, Fati̇h Di̇kmen, Ertuğrul Karaçuha, Yury Alexanderovich Tuchkin

Turkish Journal of Electrical Engineering and Computer Sciences

A new strong mathematically rigorous and numerically effective method for solving the boundary value problem of scalar (for example acoustic) wave diffraction by a perfectly soft (Dirichlet boundary condition) infinitely thin circular ring is proposed. The method is based on the combination of the Orthogonal Polynomials Approach, and on the ideas of the methods of analytical regularization. As a result of the suggested regularization procedure, the initial boundary value problem is equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e., to an equation of the type ( (I + H) x = b …

Dynamic Bandwidth Allocation Using Neural-Fuzzy In Atm Network, Yan Sing Chua

Student Works (2000-2009)

Dynamic bandwidth allocation is becoming one of the crucial issues in the design and research in the computer network. This is due to the continuous increasing demand of intensive applications that require more bandwidth while retaining higher quality. Dynamic bandwidth allocation utilises the current network state information to optimise the bandwidth distribution. The state information can be gathered through prediction using past data and measurement on current state. Agility and flexibility of dynamic bandwidth allocation using Neural-Fuzzy has the advantage that it can adapt to the state changes of the network. ATM network carries heterogeneous traffic and this causes the …

Diamondlike Carbon Thin Film Deposition Using A Rf Planar Coil Inductively Coupled Plasma System, Wai Soon Liew

Student Works (2000-2009)

A RF planar coil inductively coupled plasma system (ICPs) is setup for this project. The system is powered by a 13.56MHz, 550W, 500 RF generator. The RF power is transferred to the plasma via a planar induction coil. The impedance matching circuit consists of an air-core step-down transformer and a tunable vacuum capacitor. The typical E-H mode transition which is distinctive to the ICP has been observed in argon plasma, hydrogen plasma and hydrogen-methane admixture plasma. The studies carried out include the observation of intensity of light emission from the plasma, the power transferred at different pressures, the concentration of …

Effects Of Argon Dilution Of Silane On The Optical Properties And Surface Morphology Of Hydrogenated Amorphous Silicon, Choon Kheam Lim

Student Works (2000-2009)

Hydrogenated amorphous silicon (a.Si:H) was prepared using the d.c plasma grow discharge system. Two sets of samples were prepared and studied. The first set of samples referred to as the high argon dilution films were prepared from the discharge of pure silane at flow-rate of 5sccm and silane at the same flow-rate diluted in argon at flow-rates of 5, 10 and 15sccm. Similarly, the second set of sample referred to as the low argon dilution films were prepared from the discharge of pure silane at flow-rate of20sccm and silane at the same flow-rate diluted in argon at the flow-rates mentioned …

Fabrication And Application Of Fiber Bragg Grating, Wadi Harun Sulaiman

Student Works (2000-2009)

This dissertation presents the fabrication, characterization and application of short period fiber Bragg grating (FBG). The FBG is inscribed on high germania boron co-doped optical fiber by phase mask method with a 244nm continuous wave frequency doubled Argon ion laser as a laser source. The FBGs with reflectivity ranging from 98 -99.9%, bandwidth of 0.3 ~ 0.9nm and center wavelength of 1552.5 - 1553.5nm have been fabricated successfully with this method. The time taken for these inscriptions are within 10 to 30 minutes depending on alignment. The fabricated FBGs are characterized using both fiber amplifier (broadband source) and tunable laser …

Dynamic Performance Of Isolated Power Converters, David Badia

Theses

Isolated power converters are primarily used in applications where electrical galvanic isolation is required for safety purposes. They are also used in applications, which require various output voltages level. They have been studied from many different aspects, but in this thesis the fundamental circuits of the flyback, the forward and the half-bridge converters are studied and compared extensively, with regard to their dynamic performance.

This analysis will lead us to a better understanding of their behaviour, that is a crucial point in the selection of each topology for a particular application. Moreover, the dynamic response of each converter is different; …

A New Compensating Element For A Femtosecond Photoelectron Gun, Bao-Liang Qian, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Design and analysis of a new compensating element for improving the electron pulse front and compressing the pulse duration in a femtosecond photoelectron gun are described. The compensating element is a small metallic cylindrical cavity in which an external voltage is applied in such a way that a special electric field forms and interacts with the electron pulse. This electric field reduces the distances between the faster and slower electrons inside the cavity and efficiently compensates for electron pulse broadening caused by the photoelectron energy spread and space charge effects. Poisson's equation and the equation of motion are solved to …

Impact-Ionization And Noise Characteristics Of Thin Iii-V Avalanche Photodiodes, Mohammad A. Saleh, Majeed M. Hayat, Paul P. Sotirelis, Archie L. Holmes, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

It is, by now, well known that McIntyre's localized carrier-multiplication theory cannot explain the suppression of excess noise factor observed in avalanche photodiodes (APDs) that make use of thin multiplication regions. We demonstrate that a carrier multiplication model that incorporates the effects of dead space, as developed earlier by Hayat et al. provides excellent agreement with the impact-ionization and noise characteristics of thin InP, In/sub 0.52/Al/sub 0.48/As, GaAs, and Al/sub 0.2/Ga/sub 0.8/As APDs, with multiplication regions of different widths. We outline a general technique that facilitates the calculation of ionization coefficients for carriers that have traveled a distance exceeding the …

Sharing Health-Care Records Over The Internet, Jane Grimson, Gaye Stephens, Benjamin Jung, William Grimson, Damon Berry, Sebastien Pardon

Articles

Presents a novel approach to sharing electronic health-care records that leverages the Internet and the World Wide Web, developed as part of two European Commission-funded projects, Synapses and SynEx. The approach provides an integrated view of patient data from heterogeneous, distributed information systems and presents it to users electronically. Synapses and SynEx illustrate a generic approach in applying Internet technologies for viewing shared records, integrated with existing health computing environments. Prototypes have been validated in a variety of clinical domains and health-care settings

Video Compression Using Wavelets And Hierarchical Motion Estimation, Andrew Peter Byrne

Theses : Honours

This thesis investigates the benefits and the significant compression that can be obtained from data that has been decomposed using a wavelet transform. A video compression algorithm was developed that employs the wavelet transform and a hierarchical motion estimation algorithm which itself utilises benefits of the wavelet transform. Using MATLAB, a popular software tool for matrix based computation and analysis, several functions were developed which together formed the video compression algorithm. A variety of tests were conducted on a sample video sequence to ascertain the strengths and weaknesses of the techniques employed. The results, although not the same as the …

Indoor Radio Channel Of Bluetooth Technology, Kai Hock Charlie Khoo

Theses : Honours

This thesis discusses the findings of the final year project involving the characterisation of indoor radio channel specified by Bluetooth technology through theoretical analysis, simulations and actual measurements through field experiments. The concepts of indoor radio propagation effects and its statistical models arc explored. In addition, Bluetooth specifications are also studied and presented in Section 1. These provided a clear understanding of the radio propagation behaviour inside a building and the radio performance of Bluetooth specifications. Profound understanding of the propagation characteristics of the indoor radio channel is a major requirement for successful design of any indoor wireless communication systems. …

A Cable/Wireless Modulation/Demodulation Frontend Module For High Speed/Broadband Datalink, Pay Peng Clarice Chong

Theses : Honours

What are the modulation/demodulation schemes that are suitable tor cable or wireless high speed or broadband data link, between 1 Mbps to 30 Mbps? The recent adoption of modulation schemes such as OFDM, 8-VSB, OAM, for Digital Television broadcast (DTV), Asymmetrical Digital Subscriber Lines (ADSL), and Cable Modem (CM) for Internet access, is poss'1ble because of the increase bit/Hz in these modulations over conventional modulation schemes. These modulation/demodulation schemes could also offer similar advantages to dedicated data link applications such as home-networking using cable or wireless medium. This report document the project implementation of Quadrature Amplitude Modulation as the modulation …

Electron Cyclotron Resonance Heating In Spherical Plasmas: O-X-Ebw Mode Conversion In Mast, Josef Preinhaelter, M. A. Irzak, Linda L. Vahala, George Vahala

Electrical & Computer Engineering Faculty Publications

Using a full wave solution, the O-X-EBW mode conversion is examined for density and magnetic profiles in MAST. The effects of magnetic shear and the sharp density pedestal for H-mode operation are considered with an eye to understanding both electron cyclotron emission (ECE) and electron cyclotron resonance heating (ECRH).

Boron-Doped Homoepitaxial Diamond (100) Film Investigated By Scanning Tunneling Microscopy, Bing Xiao, Weihai Fu, Sacharia Albin, Jason Moulton, John Cooper

Electrical & Computer Engineering Faculty Publications

Conducting epitaxial diamond films of high quality are essential for many diamond studies and diamond electronic device fabrication. We have grown boron-doped epitaxial diamond films on type Ila natural diamond (100) substrates by microwave plasma chemical vapor deposition. A gas mixture of H₂/CH₄ was used. Boron doping was done by placing solid sources of pure boron in the microwave plasma. Homoepitaxial films with atomic smoothness were achieved under the following growth conditions: substrate temperature 900 °C, gas pressure 40 Torr, and gas flow rates of H₂/CH₄ = 900/7.2 seem. The growth rate was 0.87 …

Robust Control Of Input Limited Smart Structural Systems, Sridhar Sana, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Integration of controllers with smart structural systems require the controllers to consume less power and to be small in hardware size. These requirements pose as limits on the control input and the order of the controllers. Use of reduced order model of the plant in the controller design can cause spill over problems in the closed-loop system due to possible excitation of the unmodeled dynamics. In this paper, we present a method to design output feedback robust controllers for smart structures in the presence of control input limits considering unmodeled dynamics as additive uncertainty in the design. The performance requirements …

Multi-Level Voltage-Source Duty-Cycle Modulation: Analysis And Implementation, Keith Corzine, J. R. Baker

Electrical and Computer Engineering Faculty Research & Creative Works

Multi-level converters have become increasingly popular due to high power quality, high-voltage capability, low switching losses, and low EMC concerns. Considering these advantages, the multi-level converter is a suitable candidate for implementation of future naval ship propulsion systems. This paper focuses on modulation techniques for the multi-level converter. In particular, a novel voltage-source method of multi-level modulation is introduced and compared to existing methods. The proposed method is discrete in nature and can therefore be readily implemented on a digital signal processor (DSP). The method is also readily extendable to any number of voltage levels. Results of experimental implementation are …

Art/Sofm: A Hybrid Approach To The Tsp, Narayan Vishwanathan, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

We present a new method of solving large scale travelling salesman problem (TSP) instances using a combination of adaptive resonance theory (ART) and self organizing feature maps (SOFM). We divide our algorithm into three phases: phase one uses ART to form clusters of cities; phase two uses a novel modification of the traditional SOFM algorithm to solve a slight variant of the TSP in each cluster of cities; and phase three uses another version of the SOFM to link all the clusters. The experimental results show that our algorithm finds approximate solutions which are about 13% longer than those reported …

The Design And Analysis Of An Analog Ratio Spectrum Circuit, Liping Deng, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

The ratio spectrum (RS) is a novel method for signal analysis that has been successfully demonstrated for speech recognition and coding applications. In this paper, an improved RS circuit with an adaptive tenth-order Butterworth low-pass filter has been designed. We also present the first convergence analysis of the ratio spectrum. We derive linearized convergence expressions for the RS and compare the theoretical predictions to circuit simulations. © 2001 IEEE.

A Statistical Solution To A Text Decoding Challenge Problem, Xindi Cai, Rui Xu, Donald C. Wunsch, V. A. Samaranayake

Electrical and Computer Engineering Faculty Research & Creative Works

Given an encoded unknown text message in the form of a three dimensional spatial series generated by the use of four smooth nonlinear functions, we use a method based on simple statistical reasoning to pick up samples for rebuilding the four functions. The estimated functions are then used to decode the sequence. The experimental results show that our method gives a nearly perfect decoding, enabling us to submit a 100% accurate solution to the IJCNN challenge problem

A Novel Morphological Operator To Calculate Euler Number, Zhao Zhang, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a novel morphological operator to calculate the Euler number for binary images. The operator is based on the condition of eight-connectedness for foreground and four-connectedness for background. It is significantly faster than the previous operators. The morphological operations used in border detection are discussed