Digital Commons Network^™

Adaptive Receivers For Direct-Spread And Multi-Carrier Code Division Multiple Access Systems, Xiangqun Liu

Theses

In this thesis, the detection of Direct Sequence Code Division Multiple Access (DS-CDMA) signals in an AWGN channel and Multi-Carrier (MC) CDMA signals in a time-dispersion channel is discussed.

The DS-CDMA receiver employs an adaptive multiuser interference canceler that utilizes deadzone limiters in the tentative decision stage. With weights adjusted adaptively, the prior knowledge of signal powers is unnecessary. The steady state error performance of this receiver is obtained and found to be superior to the performance of the same receiver using hard limiters for tentative decisions. The channel is considered non-fading in. this receiver.

Modeling the frequency selective channel …

Low Cost Schottky Barrier Solar Cells Fabricated On Cdse And Sb2S3 Films Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal

Faculty Publications

No abstract provided.

Biofeedback Gait Training Auditory Vs. Visual Techniques, Timothy D. Hiemenz

Electrical & Computer Engineering Theses & Dissertations

Training lower extremity amputees to walk normally is quite a difficult task. Amputees must wear a prosthesis so they can walk at all. This allows them some mobility, but their walking pattern may be unnatural. If their gait is temporally asymmetric, they need to exert more energy to move about. This research was initiated to help lower extremity amputees to walk more efficiently using biofeedback gait training. Two types of feedback were developed and tested to determine which method gave the most understandable feedback, validating its use in a clinical setting.

A normal gait cycle uses the lower limbs to …

Performance Analysis Of Antennas For Hand-Held Transceivers Using Fdtd, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

The design of antennas for hand-held communications devices depends on the implementation of simulation tools that can accurately model general topologies. The paper presents the analysis of small antennas mounted on hand-held transceivers using the finite-difference time-domain (FDTD) method. The key features of the FDTD implementation are discussed, with particular emphasis placed upon modeling of the source region. The technique is used to predict the gain patterns and broadband input impedance behavior of monopole, planar inverted F, and loop antenna elements mounted on the handset. Effects of the conducting handset chassis, the plastic casing around the device, and lumped elements …

Schottky Effect At A Metal-Polymer Interface, G. Rikken, David Braun, E. Staring, R. Demandt

Electrical Engineering

We report the observation of the Schottky effect at the interface between a metal and a semiconducting polymer by means of internal photoemission spectroscopy. The bias dependence of the barrier provides information on the electrical properties of the polymer.

Simulation Of Communication Systems, William H. Tranter, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

When both a complex system and a complex channel model are encountered, the result is typically a design or analysis problem that cannot be solved using traditional (pencil and paper) mathematical analysis. Computer-aided techniques, which usually involve some level of numerical simulation, can be a very valuable tool in these situations. The purpose of this article is to provide a tutorial review of some of the basic techniques of communication system simulation. The authors consider the basic techniques used to represent signals, generate signals, and model linear systems, nonlinear systems, and time-varying systems within a simulation. They consider the important …

Suitability Of The Present Strategic Information Technology Planning (Sitp) Methodologies To The Developing Countries, A Victor

Tanzania Journal of Engineering and Technology (TJET)

The needfor strategy formulation, or in general terms strategic planning, for IT is considered as one of the most important aspects of IT manage- ment. To this end, there are a number of IT strategy formulation method- ologies world-wide. These methodologies were developed over a span of time, starting from mid 1960's when IT use started to become a serious issue in the developed countries, and continued with the trends in IT de- velopment and use, as was applicable in those countries. Morc recent of the methodologies were developed through improvements on earlier ones, and based on the new challenges …

Hardware Assists For High Performance Computing Using A Mathematics Of Arrays, H. Pottinger, W. Eatherton, L. Mullin, T. Schiefelbein

Computer Science Technical Reports

Work in progress at the University of Missouri - Rolla on hardware assists for high performance computing and communication is presented. This research consists of a field programmable gate array based rapid prototyping environment (Chameleon) being used to evaluate hardware architectures for speedup of array partitioning and routing algorithms. These algorithms have been developed using a Mathematics of Arrays (MOA) and are optimal in the sense that they reduce normal array indexing operations to a series of primitive additions based on array shape. The method is simple yet powerful, produces algorithms which are provably correct, and are independent of dimensionality. …

Spatio-Temporal Pattern Recognition Using Hidden Markov Models, Kenneth H. Fielding

Theses and Dissertations

A new spatio-temporal method for identifying 3D objects found in 2D image sequences is presented. The Hidden Markov Model technique is used as a spatio-temporal classification algorithm to identify 3D objects by the temporal changes in observed shape features. A new information theoretic argument is developed that proves identifying objects based on image sequences can lead to higher classification accuracies than single look methods. A new distance measure is proposed that analyzes the performance of Hidden Markov Models in a multi-class pattern recognition problem. A three class problem identifying moving light display objects provides experimental verification of the sequence processing …

Noise Reduction For Speech Enhancement Using Non-Linear Wavelet Processing, Hassan Dehmani

Theses and Dissertations

The problem of speech enhancement presents many obstacles in the speech processing field. This thesis develops several speech de-noising systems that can be used in the time, fourier, and wavelet domains. We present two thresholding techniques soft and hard. The application of these thresholding techniques to noisy speech data is discussed. The combination of both wavelets and the Fourier domains with noisy phase restoration proves to yield the best results in terms of intelligibility. Informal listening tests were conducted in order to compare the effects and differences between the speech de-noising systems.

Motion Estimation Using Optical Flow Field, Jingning Pan

Dissertations

Over the last decade, many low-level vision algorithms have been devised for extracting depth from intensity images. Most of them are based on motion of the rigid observer. Translation and rotation are constants with respect to space coordinates. When multi-objects move and/or the objects change shape, the algorithms cannot be used.

In this dissertation, we develop a new robust framework for the determination of dense 3-D position and motion fields from a stereo image sequence. The framework is based on unified optical flow field (UOFF). In the UOFF approach, a four frame mode is used to compute six dense 3-D …

Blind Detection In Channels With Intersymbol Interference, Raafat Edward Kamel

Dissertations

In high speed digital transmission over bandlimited channels, one of the principal impairments, besides additive white Gaussian noise, is intersymbol interference. For unknown channels, adaptive equalization is used to mitigate the interference. Different types of equalizers were proposed in the literature such as linear, decision feedback equalizers and maximum likelihood sequence estimation. The transmitter embeds sequences with the data regularly to help the equalizer adapt to the unknown channel parameters.

It is not always appropriate or feasible to send training sequences; in such cases, self adaptive or blind equalizers are used. The past ten years have witnessed an interest in …

Simulation Analysis Of Fddi Network Using Network Ii.5 Software Package, Anastassis A. Lazarides

Theses

In recent years, one of the most exciting advances in media has been the use of fiber optics in LANs. The bandwidth provided by Fiber Optic Technology has drastically increased the number of new applications that can be supported by communication networks. In order to support a variety of services, in 1986, the American National Standard Institute (ANSI) Accredited Standards Committee (ASC) X3, and the ASC X3T9.5 Task Group developed a new standard; the Fiber Distributed Data Interface (FDDI) [1]. This is a high speed (100 Mbps) optical communication network based on a token passing mode of operation. The Medium …

Deterministic And Adaptive Routing Algorithms For Mesh-Connected Computers, Yikui Cai

Theses

The two-dimensional mesh topology has been widely used in many multicomputer systems, such as the AMETEK Series 2010, Illiac IV, MPP, DAP, MasPar MP-1 and Intel Paragon. Its major advantages are its excellent scalability and simplicity. New generation multicomputer uses a switching technique called wormhole routing. The essential idea of wormhole routing is to advance a packet directly from incoming to outgoing channel without sorting it, as soon as enough information has been received in the packet header to select the outgoing channel. It has advantages of low latency and low error rate. The problems addressed by this thesis are …

Performance Analysis Of The "Fiber Distributed Data Interface (Fddi) Network" Using Petri Nets And Spnp Software Package, Savvas Eteoclis Christodoulou

Theses

The main purpose of this thesis is to model a "Fiber Distributed Data Interface" (FDDI) Network using Petri Nets, and to analyze its performance with the help of the SPNP software package. The verification of a communication protocol, by modeling it as a discrete-event system using Petri Nets is a new approach.

The correlation between the throughput rate, voice and data throughput, and the parameters of the system, such as the network load and the network speed are investigated. An overview of the "Fiber Distributed Data Interface" is provided, along with its network protocol and the limitations of its operating …

Fast Adaptive Algorithms For Signal Separation, Robert A. Manzo

Theses

LMS and RLS type algorithms are suggested for decorrelation of multi-channel systems outputs. These algorithms act as signal separators when applied to unknown linear combinations of the inputs. The performance of the suggested algorithms is compared with that of the conventional LMS and RLS algorithms that minimize the mean square error. It. is shown that the correlation matrix eigenvalue spread associated with the LMS decorrelator is always smaller than the eigenvalue spread corresponding to the conventional LMS. resulting in faster convergence speed for the decorrelator. A new RLS type decorrelator algorithm is suggested. The RLS decorrelator is shown to be …

Interference Cancellation By Time Adjustable Sampling, Josko Zec

Theses

The problem of improving the frequency response of linear arrays is addressed in this thesis. The improvement is measured in the level of rejection of the undesired sources. A new, simple, and practical method is suggested. It is based on adjusting the sampling time in selected channels. Interference cancellation for finite bandwidth signals is accomplished only at, or close to, the carrier frequency. Wideband cancellation requires additional hardware and computational complexity. Conventional way of the wideband interference cancellation utilizes tapped delay line adaptive filters in each channel.

The Time Adjustable Sampling (TAS) method achieves a part of the tapped delay …

Motion Compensation Using Correlation-Feedback, Zebiba Shifa

Theses

Motion compensation is widely used for exploiting temporal redundancies in the coding of image sequences. Accurate estimation of motion information in image sequences is important in motion-compensated coding. Different approaches have been used to estimate motion to obtain the motion-compensated frame difference signal.

This work uses the correlation-feedback approach to estimate the velocity or the optic flow of the moving image pixel. After the motion of the pixel is estimated. the motion-compensated frame difference signal is found by subtracting the current. frame from the predicted frame.

This correlation-feedback approach estimates the true motion vector of moving image accurately. Consequently, the …

Narrow-Band Interference Rejection In Spread Spectrum Using An Eigen Analysis Based Approach, Aparna Vadhri

Theses

A new adaptive technique is suggested for rejecting narrow-band interferences in spread spectrum communications. When data is coded using a pseudo-noise code, the received signal consists of a wide-band signal with almost white spectral properties, thermal noise, and correlated narrow-band interferences. A new approach is proposed which exploits the statistical properties of the received signal via eigenanalysis of the received data. While the energy of the wide-band signal is distributed over all the eigenvalues of the signal autocorrelation matrix, the energy of the interference is concentrated in a few large eigenvalues. Hence, the eigenvectors corresponding to the large eigenvalues are …

The Effects Of Channel Curvature And Protusion Height On Nucleate Boiling And The Critical Heat Flux Of A Simulated Electronic Chip, John E. Leland

Office for Research Publications and Presentations

The quest for higher power yet smaller electronics has given rise to the need for very effective cooling of these electronics. Because one of the foremost problems in electronics cooling is achieving high heat flux cooling within small packages while expending minimal pumping power, one focus of this study was to investigate the effects of channel curvature on the CHF. Experimental data were obtained for flow rates of 1-7 m/s, subcoolings of 5-35"C, and radii of curvature of 25.4 and 50.8 mm. A correlation was obtained for these data which provided an excellent fit.

One condition that has been ignored …

On Issues Of Equalization With The Decorrelation Algorithm : Fast Converging Structures And Finite-Precision, Andrew James Bateman

Theses

To increase the rate of convergence of the blind, adaptive, decision feedback equalizer based on the decorrelation criterion, structures have been proposed which dramatically increase the complexity of the equalizer. The complexity of an algorithm has a direct bearing on the cost of implementing the algorithm in either hardware or software. In this thesis, more computationally efficient structures, based on the fast transversal filter and lattice algorithms, are proposed for the decorrelation algorithm which maintain the high rate of convergence of the more complex algorithms. Furthermore, the performance of the decorrelation algorithm in a finite-precision environment will be studied and …

Advanced Navigation For Planetary Vehicles Applying An Approximate Mapping Technique, Timothy R. Mcjunkin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis provides a method for compressing the information provided by JPL Mars rover obstacle sensors by creating an approximate map of the terrain around the vehicle. This thesis demonstrates that this method provides adequate information for a human operator to negotiate complex obstacles fields.

By dividing the area around the vehicle into regions and classifying each region as to how dangerous (impassable), the sensor data can be accumulated with minimal overhead. The terrain in each region has a number between zero and one, with zero meaning completely passable and one meaning completely impassable. A continuum of possible values between …

The Design Of An Augmentative Communications Device, Darren Blaser, Scott Sorenson

Undergraduate Honors Capstone Projects

There is an extremely large number of people in the modem world who have difficulty communicating. Among these are approximately 25 million people with cerebral palsy. Cerebral palsy is a disability that is usually caused during, or shortly after birth. Cerebral palsy usually affects a person's motor skills and sense of balance, often rendering them incapable of speaking clearly enough to be understood well. Because this group of people cannot communicate as effectively as other individuals, many uninformed people suppose they do not have as great a need to speak, to say things like, "How are you?", ''I'm Hungry", "Thank …

Multirate Time-Frequency Distributions, John R. O'Hair

Theses and Dissertations

Multirate systems, which find application in the design and analysis of filter banks, are demonstrated to also be useful as a computational paradigm. It is shown that any problem which can be expressed a set of vector-vector, matrix-vector or matrix-matrix operations can be recast using multirate. This means all of numerical linear algebra can be recast using multirate as the underlying computational paradigm. As a non-trivial example, the multirate computational paradigm is applied to the problem of Generalized Discrete Time- Frequency Distributions GDTFD to create a new family of fast algorithms. The first of this new class of distributions is …

Logic Synthesis With High Testability For Cellular Arrays, Andisheh Sarabi

Dissertations and Theses

The new Field Programmable Gate Array (FPGA) technologies and their structures have opened up new approaches to logic design and synthesis. The main feature of an FPGA is an array of logic blocks surrounded by a programmable interconnection structure. Cellular FPGAs are a special class of FPGAs which are distinguished by their fine granularity and their emphasis on local cell interconnects. While these characteristics call for specialized synthesis tools, the availability of logic gates other than Boolean AND, OR and NOT in these architectures opens up new possibilities for synthesis. Among the possible realizations of Boolean functions, XOR logic is …

Plains Electric Members Service Area_04-29-1994, University Of New Mexico Bureau Of Business And Economic Research

BBER Publications

This report presents historical and projected socioeconomic data for 19 New Mexico and two Arizona counties which comprise the service areas of the distribution cooperatives in the Plains Electric Generation and Transmission Cooperative, Inc., system.

Developing A Benchmark For Evaluating The Performance Of Parallel Computers, D. Ladd Williamson

Undergraduate Honors Capstone Projects

This paper discusses the development of a portable suite of benchmarking programs for parallel computers. Comparative measurement of the performance of parallel computing systems has been limited because of the great diversity of architectures and of processor interconnection schemes. One solution is to translate benchmark codes into a consistent and portable parallel language. This paper reports on progress in developing such a portable suite of benchmarks. An extensive introduction to parallel computing is included as an appendix, to provide a thorough understanding of the factors complicating development of the performance suite. Key to the development was the use of p4, …

Donor Complex Formation Due To A High-Dose Ge Implant Into Si, Ashawant Gupta, M. Mahmudur Rahman, Jianmin Qiao, Cary Y. Yang

Electrical and Computer Engineering

To investigate boron deactivation and/or donor complex formation due to a high‐dose Ge and C implantation and the subsequent solid phase epitaxy, SiGe and SiGeC layers were fabricated and characterized. Cross‐sectional transmission electron microscopy indicated that the SiGe layer with a peak Ge concentration of 5 at. % was strained; whereas, for higher concentrations, stacking faults were observed from the surface to the projected range of the Ge as a result of strain relaxation. Photoluminescence (PL) results were found to be consistent with dopant deactivation due to Ge implantation and the subsequent solid phase epitaxial growth of the amorphous layer. …

A State Architecture Notation Specification Of The Electronic Industries Association Rs-232-C Generic Interchange Circuit, Nelson E. Hastings

Masters Theses

The Electronic Industries Association (BIA) RS-232-C recommendation is an interface specification which was introduced in August 1969 and presents a natural language specification of a 25 pin binary serial data interface between a Data Communication Equipment (DCE) and a Data Terminal Equipment (DTE). The exchange of data signals between a DCE and a DTE ultimately provides the means for DTEs to communicate on networks of DCEs interconnected by different transmission mediums possibly over great distances. The exchange of data signals between a DCE and a DTE occurs at an interface via interchange circuits.

In this thesis we will create a …

Characterization Of Electromagnetically Coupled Superquadric Loop Antennas For Mobile Communications Applications, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

Analysis of two mutually coupled loop antennas with arbitrary relative orientation and position and possibly different geometries is presented. The antennas are represented by generalised superquadric curves, which include circular, elliptical, and rectangular loop geometries, and they may be located either in a homogeneous region or next to an infinite ground plane. A Galerkin-type moment method with piecewise sinusoidal subsectional basis and weighting functions is used. Special consideration is given to implement the solution using curved wire segments instead of the commonly employed linear segments to improve computational efficiency. This very general computational tool is used to investigate the behaviour …