Digital Commons Network^™

Dynamic Task Scheduling For The Atamm Multicomputer Operating System Using Embedded Firmware On Microcontrollers, Sudhir Sastry

Electrical & Computer Engineering Theses & Dissertations

A dynamic task scheduling strategy for the distributed processing of large grain dataflow algorithms using embedded firmware on an ATAMM testbed consisting of interconnected microcontrollers is presented in this thesis. The ODU/NASA developed Algorithm to Architecture Mapping Model, ATAMM, uses marked graph models to specify data and control flow for the execution of iterative, deterministic large grain dataflow algorithms in a multicomputing environment. The testbed consists of a bank of four 68HC11 microcontrollers that communicate over a token bus. The token bus arbitration scheme used is contention free and well suited for real-time computing applications. The execution of data flow …

Diamond Thin Film Sensors For Hypersonic Flow Studies, Bhaskar Kumar Bulusu

Electrical & Computer Engineering Theses & Dissertations

Conventional metal film sensors can measure flow instabilities of the order of 60 kHz. The turbulence fluctuations in the hypersonic regime are of the order of 200- 400 kHz. To measure these fluctuations, sensors with an enhanced frequency response are required. Therefore, it is required to identify the parameters to enhance the frequency response. These include parameters such as the temperature sensitivity, the resistivity, the thermal conductivity, the diffusivity, specific heat capacity and the geometric size and shape of the film and the substrate. A selection of materials was then carried out to maximize the frequency response. Diamond was identified …

An Artifically Intelligent Word Recognizer To Control Appliances And Switches: The Home That Listens To Your Every Command, Joseph Bauer, Rick Steurer

Opportunities for Undergraduate Research Experience Program (OURE)

The most natural and informal means of communication and control is speech communication. Therefore, it also goes to say that control of home appliances, stereo, computer, and heating thermostat to name a few will naturally tend to this form of control.

A word recognition home controller was designed, constructed, and tested successfully. This paper will discuss the low-cost overall design, implementation, and results of a presently constructed and working "home controller." The results of this successful project in voice control are very promising and agree with the original hypothesis: A home that listens to your command is very much a …

Clustering Techniques In Speaker Recognition, Douglas N. Prescott

Theses and Dissertations

This thesis presents a comparison based on identification rate, of three clustering techniques applied to cepstral features for speaker identification. LBG vector quantization as developed by Linde, Buzo and Gray; is used to provide benchmark performance for comparison with Fuzzy clustering (based on the unsupervised fuzzy partition-optimal number of classes, UFP-ONC algorithm by Gath and Geva) and an Artificial Neural Network, the Multilayer Perceptron. Cepstral features from the TIMIT, King and AFIT93 corpus speaker databases are used to produce speaker-identification classifiers using each of the clustering algorithms. The experiment reported evaluates the speaker identification performance using the 20-dimensional cepstral features …

Classification Using Set-Valued Kalman Filtering And Levi's Decision Theory, T.K. Moon, Scott E. Budge

Electrical and Computer Engineering Faculty Publications

We consider the problem of using Levi's expected epistemic decision theory for classification when the hypotheses are of different informational values, conditioned on convex sets obtained from a set-valued Kalman filter. The background of epistemic utility decision theory with convex probabilities is outlined and a brief introduction to set-valued estimation is given. The decision theory is applied to a classifier in a multiple-target tracking scenario. A new probability density, appropriate for classification using the ratio of intensities, is introduced.

Epistemic Decision Theory Applied To Multiple-Target Tracking, T. K. Moon, Scott E. Budge, W. C. Stirling, J. B. Thompson

Electrical and Computer Engineering Faculty Publications

A decision philosophy that seeks the avoidance of error by trading off belief of truth and value of information is applied to the problem of recognizing tracks from multiple targets (MTT). A successful MTT methodology should be robust in that its performance degrades gracefully as the conditions of the collection become less favorable to optimal operation. By stressing the avoidance, rather than the explicit minimization, of error, the authors obtain a decision rule for trajectory-data association that does not require the resolution of all conflicting hypotheses when the database does not contain sufficient information to do so reliably. This rule, …

Transient Behavior Of An Adaptive Synchronous Cdma Receiver, Bin Zhu

Theses

A steepest descent algorithm is used to update the adaptive weights of a two-stage synchronous Code-Division Multiple-Access (CDMA) receiver that was proposed recently. An issue of the adaptive CDMA system - the convergence and stability property of the receiver is investigated in this thesis.

This adaptive synchronous CDMA receiver uses a decorrelator at the first stage and adopts a neural network which acts as an interference canceler at the second stage. It can achieve near-optimum performance. Furthermore, its computational complexity is just a square function of the number of users. The only requirement is the knowledge of the users' signature …

An Adaptive Fusion Model For Distributed Detection Systems With Unequiprobable Sources, Yuzheng Zhang

Theses

In a traditional communication system, a single sensor such as a radar or a sonar is used to detect targets. Since the reliability of a single sensor is limited, distributed detection systems in which several sensors are employed simultaneously have received increasing attention in recent years. We consider a distributed detection system which consists of a number of independent local detectors and a fusion center. Chair and Varshney have derived an optimal decision rule for fusing decisions based on. the Baysian criterion. To implement such a rule, the probability of detection P_D and the probability of false alarm …

An On-Line Approach For Evaluating Trigonometric Functions, Rajesh Amin

Theses

This thesis investigates the evaluation of trigonometric functions based on an on-line arithmetic approach. On-line algorithms have been developed to evaluate the sine and cosine functions. Error analysis and heuristics are carried out to arrive at a minimal error algorithm based on the series expansion of the sine and cosine function.

A logical design based on the algorithm is presented where the unit is designed as a set of basic modules. A detailed bit slice design of each module is also presented. A simulator was designed as an experimental tool for synthesis of the on-line algorithms, and a tool for …

A Graphical Tool For Timed Petri Nets Using Object Oriented Programming, Baopu Liu

Theses

The objective of this effort is to develop a computer tool for drawing, editing and simulating Timed Petri Nets using object oriented programming. The developed C++ based Timed Petri Net Simulation Tool, TimedPNT, is capable of simulating discrete systems with both deterministic and stochastic delays. Preselection is used for conflict resolution. Performance and utilization results are automatically collected. XView™ Toolkit is used for building the TimedPNT's interactive graphical interface in compliance with AT&T's OPENLOOK® standard on a SunSparc™ IPX running SunOSTM 4.1.2. Compliance with the X Window standard makes the developed tool portable to other X Window based systems.

Performance Of National Research And Education Network While Transmitting Healthcare Information Data, Bhavesh Mahendra Shukla

Theses

National Research and Education Network(NREN) is a first step in the process of building a National Information Infrastructure(NII). NII will ultimately lead to Broadband Integrated Services Digital Network(B-ISDN), a network which will support global exchange of voice, data, images and video.

NREN will evolve out of present National Science Foundation Network (NSFNET), also known as Interim NREN. At present NSFNET operates at 45 MBits/sec. By 1996, there are plans to boost the data rate to 155 MBits/sec and to 620 MBits/sec by the turn of century.

In this thesis, present actual NSFNET is simulated using software simulation tool Networkll.5. The …

Investigation Of Reduced Hypercube (Rh) Networks : Embedding And Routing Capabilities, Michalis A. Sideras

Theses

The choice of a topology for the interconnection of resources in a distributed-memory parallel computing system is a major design decision. The direct binary hypercube has been widely used for this purpose due to its low diameter and its ability to efficiently emulate other important structures. The aforementioned strong properties of the hypercube come at the cost of high VLSI complexity due to the increase in the number of communication ports and channels per node with an increase in the total number of nodes. The reduced hypercube (RH) topology, which is obtained by a uniform reduction in the number of …

Performance Modeling Of High Data Rate Ring Networks Using Stochastic Petri Nets, Le Zhong

Theses

This thesis has proposed a performance analysis method for Carrier Sensing Multiple Access Ring Network (CSMA) based on Petri net methodologies. The method can offer more accurate results than traditional queuing methods, but less than simulation results. In the CSMA network access protocol is studied in this thesis, when a passing message is detected by a station, it stops transmitting immediately in order to avoid a collision.

A generalized stochastic Petri nets model is made first, then the SPNP package is used to do the analysis. The analysis results show that even at a very heavy load fraction of near …

A Hybrid Low Bit-Rate Video Codec Using Subbands And Statistical Modeling, Ferhat Cakrak

Theses

A hybrid low bit-rate video codes using subbands and statistical modeling is proposed in this thesis. The redundancy within adjacent video frames is exploited by motion estimation and compensation. The Motion Compensated Frame Difference (MCFD) signals are decomposed into 7 subbands using 2-D dyadic tree structure and separable filters. Some of the subband signals are statistically modeled by using the 2-D AR(1) technique. The model parameters provide a representation of these subbands at the receiver side with a. certain level of error. The remaining subbands are compressed employing a classical waveform coding technique, namely vector quantization (VQ).

It is shown …

Coordination Of Time-Overcurrent Relays For High-Speed Power Line Protection, Nicos Charalambous

Theses

A properly coordinated protection system is essential to ensure that an electricity distribution network can operate within its requirements, regarding the safety of a power system. Automatic operation is necessary to isolate faults on a power system in a minimum time. The study of time coordination of relays suggests improved ways of power line protection. The protection must be sensitive enough to operate when a fault occurs under minimum fault conditions, yet be stable enough not to operate when its associated equipment is carrying the maximum rated current, which may be a short-time value. A power system is used as …

Coping With The Risk Of Cancer In Children Living Near Power Lines, Eileen N. Abt

RISK: Health, Safety & Environment (1990-2002)

Ms. Abt briefly summarizes evidence linking power lines with a possible increase in risk of childhood cancer. She also recounts how, although many experts remain skeptical of causality, public fears, whether or not warranted, have themselves created serious problems. Finally, she proposes ways to address those problems.

Scheduling Of Unstructured Communication On The Intel Ipsc/860, Jhy-Chun Wang, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

In this paper we present several algorithms for decomposing all-to-many personalized communication into a set of disjoint partial permutations. These partial permutations avoid node contention as well as link contention. We discuss the theoretical complexity of these algorithms and study their effectiveness both from the view of static scheduling and from runtime scheduling. Experimental results for our algorithms are presented on the iPSC/860.

Block Qpsk Modulation Codes With Two Levels Of Error Protection, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

A class of block QPSK modulation codes for unequal error protection (UEP) is presented. These codes are particularly suitable either for broadcast channels or for communication systems where parts of the information messages are more important than others. An example of the latter is coded speech transmission. Not much is known on the application of block UEP codes in combined coding and modulation schemes. We exhibit a method to combine binary linear UEP (LUEP) block codes of even length, using a Gray mapping, with a QPSK signal set to construct efficient block QPSK modulation codes with nonuniform error protection capabilities …

On A Class Of Optimal Nonbinary Linear Unequal-Error-Protection Codes For Two Sets Of Messages, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

Several authors have addressed the problem of designing good linear unequal error protection (LUEP) codes. However, very little is known about good nonbinary LUEP codes. We present a class of optimal nonbinary LUEP codes for two different sets of messages. By combining t-error-correcting ReedSolomon (RS) codes and shortened nonbinary Hamming codes, we obtain nonbinary LUEP codes that protect one set of messages against any t or fewer symbol errors and the remaining set of messages against any single symbol error. For t ≥ 2, we show that these codes are optimal in the sense of achieving the Hamming lower bound …

Journal Of Engineering Education Round Table: Reflections On The Grinter Report, James G. Harris, Eugene M. Deloatch, William R. Grogan, Irene C. Peden, John R. Whinnery

Electrical Engineering

The Round Table is a new presentation format for the Journal of Engineering Education. The purpose of the Round Table is to present the comments of several distinguished individuals about a topic as well as their responses to the comments offered by their colleagues. For the initial Journal of Engineering Education Round Table we asked for reflections about the Grinter Report, published in September 1955.

After a brief introduction to the topic of discussion, the invited participants present their views, and, then, respond to the remarks of their colleagues. The goal is two-fold: to present a spectrum of views on …

An Efficient Method For Representing And Computing Transitive Closure Over Temporal Relations, Vincent J. Kovarik

Retrospective Theses and Dissertations

The need for temporal reasoning is found throughout the engineering disciplines. James Allen introduced a representation for temporal reasoning based upon the concept of intervals. This approach provides a rich set of temporal relations for reasoning over events and changes in state. The full temporal algebra is NP-complete however. The algorithm developed by Allen executes in 0(n³) time but only ensures consistency between any three intervals.

This research presents an approach to representing interval relations as a bit-encoded form which captures the relationships between the end-points of the intervals. A bit-algebra is then defined which provides an …

Comparison Of Self Pulsation In Multisection Lasers With Distributed Feedback And Intracavity Satuarable Absorbers, P. Phelan, D. Mcdonald, A. Egan, Joe Hegarty, R. O'Dowd, Gerald Farrell, S. Lingren

Articles

The authors report a comparison of the self-pulsing characteristics of two types of semiconductor laser. They show that the self-pulsing frequency of the DFB laser is decoupled from the resonance frequency. They discuss the various characteristics, their significance in relation to optical synchronisation, and use the results to suggest a possible explanation for the mechanism for self-pulsation in the DFB laser.

Comparison Of High-Temperature Superconductors In Multi-Chip Module Applications, D. E. Ford, S. S. Scott, S. S. Ang, W. D. Brown

Journal of the Arkansas Academy of Science

In the application of high-temperature superconductors (HTSCs) in multi-chip module (MCM) technology, it is first necessary to investigate the advantages and disadvantages of the various HTSC compounds. The standard criteria for comparing the suitability of HTSCs in electronics applications has been critical temperature (Tc )and critical current density (Jc ). It is also necessary to consider the physical properties of HTSCs in relation to the various processing techniques required in fabrication of MCMs. These techniques can be grouped into four main areas: deposition, patterning, packaging, and characterization. The four main HTSC materials, Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O, Tl,Ba-Ca-Cu-O and Hg-Ba-Ca-Cu-O, will be compared …

Gamma Ray Emissions From Binary Pulsar Systems, Tony A. Hall, Andrew T. Sustich

Journal of the Arkansas Academy of Science

A method is developed for estimating the gamma ray flux impinging upon the earth from production in binary pulsar systems. We calculate production of the 6.13 MeV gamma ray line characteristic of 16O. These are produced by protons emitted by the pulsar interacting with 16O atoms at the surface of the companion. We examine different types of companion stars and estimate the gamma ray flux at the earth as a function of proton emission from the pulsar and distance from the earth. Prospects for detection from earth are discussed.

Investigation Of Cebus Traffic Across A Router, With And Without Acknowledgment, Wannakuwattawaduge Lalith Fernando

Theses

A power line and twisted pair implementation of the Consumer Electronic Bus(CEBus) has great potential toward inexpensive home automation. Since the introduction of the CEBus Standard, there has been increasing efforts on evaluating its performance. However, most of the work has been performed for unacknowledged networks. Pan[18] was able to implement an acknowledged network for PL CEBus. In this thesis, the acknowledgment process has been taken one step further. The effect of acknowledgment on a Power Line and Twisted Pair CEBus network interconnected by a router is studied. CEBus network performance parameters such as message and packet delays, message throughput, …

An Analysis Of The Payback Potential Of New Lighting Technology, James L. Cox

Masters Theses

Recent, energy saving improvements in lighting technology have been made involving the use of more efficient lamps, silver coated light reflectors, and electronic light ballasts. Research indicates that it is economically feasible to retrofit existing light fixtures to utilize the advantages of these developments. This process consists of the removal of all standard lamps and ballasts in each light fixture, the installation of a highly refined light reflector and the replacement of the existing lamps with brighter, more efficient ones. Standard magnetic ballasts are exchanged for more efficient electronic ballasts. Resulting is a light fixture that produces a comparable amount …

Automation Of Formation Flight Control, Vincent P. Reyna

Theses and Dissertations

The research contained in this thesis explores the concepts of Automated Formation Flight Control documented in three previous AFIT theses. The generic formation analyzed consists of a Leader and Wingman, with the Wingman referencing its maneuvers off of Leader maneuvers. Specifically, planar formation flight control concerning only heading and velocity changes is considered. Next, the vertical separation constraint is relaxed to allow wing maneuvers outside of the flight plane of the lead in order to minimize the energy expended by the wing in a maneuver. Analysis of the two forms of formation flight control investigated in this thesis reveals the …

Programmable Analog Array Circuit, Marek Perkowski, Edmund Pierzchala

Electrical and Computer Engineering Faculty Publications and Presentations

There is disclosed a programmable analog or mixed analog/ digital circuit. More particularly, this invention provides a circuit architecture that is ?exible for a programmable electronic hardWare device or for an analog circuit Whose input and output signals are analog or multi-valued in nature, and primarily continuous in time. There is further disclosed a design for a current-mode integrator and sample-and-hold circuit, based upon Miller effect.

Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall

Theses and Dissertations

This thesis develops and evaluates a number of new concepts and tools for the analysis of signals using Malvar wavelets lapped orthogonal transforms . Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By utilizing the Malvar wavelet, any signal distortion resulting from the transformation can be eliminated or cancelled during reconstruction. This is accomplished by placing conditions on the window and the basis function and then incorporating the window into the orthonormal representation. Paradigms for both a complex-valued and a real-valued Malvar wavelet are summarized. I-lie algorithms for the wavelets were …

Developing A Graphical User Interface To Support A Real-Time Digital Signal Processing System, Jeffrey C. Miller

Theses and Dissertations

A graphical software user interface for a VMEbus-based real-time digital signal processing system was designed. Use, requirements were defined and the Rumbaugh object-oriented analysis and design technique was applied to analyze the requirements and produce an object-oriented design. The software design includes a graphical, mouse- and keyboard driven user interface, specialized hardware driver modules, and operating system interfaces. An implementation plan was also developed to map the design into the C programming language using existing system code, automatically generated code, and newly written code. Based on the implementation plan, a limited software system prototype w successfully developed and demonstrated. The …