Digital Commons Network^™

High Frequency Scattering Code In A Distributed Processing Environment, Scott Suhr

Theses and Dissertations

Government agencies and academic institutions are very interested programming for concurrent processing to cut computer processing time. However, many of the world's problems have already been coded for conventional serial computers. This research demonstrates the feasibility of modifying existing serial codes for execution in a concurrent processing environment. A electromagnetic scattering prediction code known as NECBSC is incrementally modified to incorporated various levels of concurrent computing. The data processed by the code are completely independent, providing an avenue for data decomposition of the process. Portions of the data set are processed on each mode and the results combined for final …

Pump Polarization Effects In Cw Dye Lasers, Lee W. Casperson, W. J. Sandle, A. C. Wilson, D. M. Warrington, R. J. Ballagh

Electrical and Computer Engineering Faculty Publications and Presentations

The effects of pump polarization on the performance of cw dye lasers have been investigated. A recently developed semiclassical model for synchronously pumped mode‐locked dye lasers is adapted to the problem of cw dye‐laser oscillation, and analytic expressions are obtained for the relationship between the pump power, pump polarization, and dye‐laser output power. The theoretical results are compared with experimental data obtained using an argon‐laser‐pumped rhodamine 6G dye laser.

Mosfet Audio Amplifier, Jeff Argast

Undergraduate Honors Capstone Projects

My senior project is an audio amplifier utilizing MOSFETs as the output transistors to drive the speaker. Within this document I cover the details of designing an amplifier, and the methods used to build it.

The most important part of the project is the output stage. In this section I chose MOSFETs over BJTs. Several advantages ensued from this decision, resulting in a simple design.

Further, the transformer must be able to supply the necessary currents for the transistors. Because large musical peaks are possible, resulting in sizable power surges, I had to obtain a large transformer with adequate specifications. …

An Alternative Algorithm For Discrete-Time Filtering, Frederick H. Zeitz Iii

Theses and Dissertations

The discrete-time Kalman filter is a conditional mean estimator of the states of a linear stochastic process, conditioned on the previous state and current measurements. It assumes that the states and noise inputs can be represented as jointly Gaussian random variables. The influence diagram is a decision analysis tool. Under certain conditions, it can represent continuous, jointly Gaussian random variables. The conditioning order of the random variables may be changed (using Bayes' rule) so that any random variable can be conditioned on any other subset of random variables in the diagram. Under these conditions, an influence diagram can represent the …

Performance Analysis Of Symbol Timing Recovery Circuits Employed In Digital Communications Systems, Elisha Yegal Bar-Ness

Theses

An analytical approach is presented for the jitter performance of a timing recovery circuit consisting of a prefilter, a zero-memory nonlinear device, and a narrow band postfilter tuned to the pulse repetition frequency. Assuming first a squarer type of nonlinearity, analytical expressions for the rms jitter in the timing wave are obtained as a function of the pre and post filtering characteristics. These expressions are suitable for judging the case where the baseband signal is bandlimited. Also for some specific examples, the jitter performance of this kind of STR circuit is evaluated.

Secondly, a general type of nonlinerity is assumed, …

The Design And Testing Of A Personal Computer Controlled Scanning Acoustic Microscope For Orthopaedic Surgical Applications, Hubert Heinrich Berndt

Theses

This thesis describes scanning acoustic microscopy and ultrasonic image processing to characterize and evaluate materials of known properties, as well as novel materials. This work describes the assembly and testing of a PC based device for nondestructive evaluation of bone materials for usage in orthopaedics research. It includes the identification of some hardware problems and their solution, and it also describes different image processing techniques that have been developed and applied in this work. In a growing number of disciplines it has been discovered that an acoustic microscope can provide new information, especially about the elastic properties of specimens and …

Electroretinogram Modeling : Parameter Identification And Intensity-Response Function Fits, Juan J. Castro

Theses

Electroretinography testing provides many useful techniques for clinical diagnosis of the visual system. However, the interpretation of the electroretinogram data involves a great amount of subjectivity. The use of mathematical models and parameter estimation techniques to fit the electroretinogram data supply a non-subjective and more standard way for analysis of the electroretinogram data. Mathematical models provide a way of summarizing the information enclosed in the raw electroretinogram response into a small set of parameters that define the response.

This thesis presents a mathematical model for the electroretinogram response due to light stimuli. It also provides a non-subjective method for obtaining …

A Mouse-Driven Interface For Androx Ics-400, Chin-Tien Chen

Theses

A mouse-driven interface is extremely useful for software performing image processing tasks. This thesis describes an implementation of a mouse-driven interface for the Androx ICS-400 image processing board. The Androx board is housed in a Sun 4/330 running a UNIX-based operating system. The main goal of this interface is to provide a consistent and friendly user interface for image processing tasks and integrating the Sun window libraries with the Androx libraries. Various image processing tasks, such as gray scale and binary morphological operations, histogram, thresholding, filtering, spot, logical operations, arithmetic operations, zooming, scrolling, rank and image acquisition are implemented in …

Application Of Non-Imaging Optical Inspection To The Detection Of Pinhole Defects In Latex Condoms, Paul Micha Gelencser

Theses

An optical technique was demonstrated for the detection of pinhole defects in latex condoms. To evaluate the optical inspection concept, a prototype inspection apparatus was constructed. In order to maximize contrast between pinhole transmitted signal and optical signal transmitted through the latex condom material, ultraviolet (u.v.) light of wavelength 253nm has been used. This inspection was performed during rotation of the condom, with the light source inside the condom and the photomultiplier photodetector outside. The form on which the condoms were mounted was made of quartz in order to allow the u.v. light to be transmitted through it.

Background signal …

Modeling Of Vacuum Microelectronic Lateral And Vertical Devices, Qiong Gui

Theses

Vertical and lateral configurations of the vacuum microelectronic device have been modeled using the simulation tools. Both cone and ridge cathode structures are used. Simulation results are compared with experimental data where available. These device structures include cathode, extraction grid, anode, and deflectors. The electric field at the tip of the cathode has been calculated for tip radius as small as 0.1nm. The model used takes into account the effect of potential on all electrodes on the E-field at the cathode tip. Also the effect of cathode geometry on the E-field is detailed.

Static characteristics are based on a new …

Automatic Infrared And Visual Inspection Of Solder Joints On Pcbs, Jiang Huang

Theses

This thesis reports the research results of automatic inspection of solder joints on printed circuit boards (PCBs). The previous work on this regard has been advanced significantly in the following three aspects. With the application of some microlens and the principle of geometric optics solder joints of real size are inspected in this work instead of larger simulation solder joints in the previous work. A new set of features is formulated and used for infrared inspection. Consequently, better results have been achieved in this work.

Reasonably good results demonstrate the capability of infrared inspection of solder joints on PCBs. Once …

Workstation Allocation Schemes For Response Time Improvement In A Multiserver Pc Lan, Asit V. Merchant

Theses

Microcomputer Local Area Networks have recently become quite popular. Higher demand in term of number of users who contribute a variable amount of load has led to Multiple File servers in a LAN. As a result of variable load, response time at workstations differ significantly depending not only on total load on the network but also on workstation distribution across servers. The goal of this study is to develop schemes to keep response time as low as possible and constant among workstations. This study is based on minimizing response time and containing it or keeping it constant by distributing workstations …

A Comparative Study Of Image Coding Techniques : Filter Banks Vs. Discrete Cosine Transform, Hosam Fawzi Mutlag

Theses

Subband coding of still image frames using Binomial PR-QMF has been presented in this thesis. Simulation results have shown that the performance of subband coding using a low complexity coder is practically the same as the performance of the industry standard (8 x 8) DCT based image coder.

A low bit rate adaptive video coding technique is also introduced in this thesis. The redundancy within adjacent video frames is exploited by motion compensated interframe prediction. The Motion Compensated Frame Difference (MCFD) signals are filtered by employing Binomial PR-QMF structure into four subbands. Then, the subbands are quantized using an efficient …

Minimized Test Patterns For Sequential Logic, Chetan Patel

Theses

This thesis presents a novel algorithmic approach which can be used to reduce the total test pattern lengths for testing a sequential logic circuit. Test generation for sequential circuits has long been recognized as a difficult task. Several approaches have been made in the past to solve the problems of test generation stage for sequential circuits but they were either an extension of the classical D-algorithm or based on the random techniques. When number of states of the sequential circuit is larger and the test demands long input sequences, they can be quite ineffective for the test generation. The STALLION …

Analysis And Implementation Of A Navigation System Using Vanishing Points In A Generalized Environment, Rolf Schuster

Theses

The development of accurate sensors is of crucial importance in navigation of mobile autonomous robots. The following master's thesis analyzes the use of vanishing points for robot navigation. Parallel lines in the environment of the robot are used to compute vanishing points which serve as a reference for guiding a robot. To accomplish the navigation tasks, three subtasks are to be performed: detection of straight lines, computation of vanishing points, and robot navigation with vanishing points.

An edge detection algorithm is presented that combines Sobel and Laplacian of Gaussian operators. The algorithm preserves the precision of the Laplacian of Gaussian …

Bad Data Identification In Power Systems, Shichun Zou

Theses

Two classes of bad data (BD) identification methods in power system state estimation are studied.

The first class is the perturbation method. In this method, the obtained measurements are perturbed a few times. Each time a state is obtained from which measurement corrections are calculated. The statistics of the corrections corresponding to a BD are different from those corresponding to a healthy data. The method uses those differences for identification purposes.

The effectiveness of different indicators is studied. These include the normalized residual, the weighted residual, and residuals incorporating the statistics of the corrections.

The success rate of using the …

Performance Evaluation In Terms Of Congestion And Flow Control Of Interconnected Token Ring Local Area Networks, Muhammad Salim Raza

Theses

In an interconnected network, if user demands are allowed to exceed the system capacity, unpleasant congestion effects occur which rapidly neutralize the delay and efficiency advantages. Congestion can be eliminated by using an appropriate set of traffic monitoring and control procedures called flow control procedures. This thesis first investigates the major technical concepts underlying the token-ring technology; performance and flow control issues and then gives an approximate analytical solution in terms of mean end-toned delay in a system of token-ring local area network interconnected through bridges. The analytical solution is based on an approximation of the mean end-to-end delay in …

3-D Structure Recovery Using Unified Optical Flow Field Approach, Anees Ahmad

Theses

Recovery of the 3-D structure that is characterized by an N^th order factorable and/or non-factorable polynomial equation is studied in this thesis. Analytical tools have been employed to analyze and solve the problem. The solution is based on the direct method, which is derived from the unified optical flow field, which, in turn, is an extension of optical flow to spatial image sequences. Least squares formulation has been employed for optimum estimation. The method used does not require the establishment of point to point correspondence, nor the estimation of the optical flow, as an intermediate step.

The theoretical results …

Connected Component Labelling On A Pair Of Parallel Systems, Imran Shahid

Theses

Hypercubes and meshes are of the most successful parallel processing structures and are widely used in image processing applications. The mesh is a natural multiprocessor architecture for image processing because an N x N image can be directly mapped onto a mesh of N x N PEs (processing elements), holding each PE responsible for one pixel, with neighboring PEs responsible for neighboring pixels. Thus, local operations can be performed on the image, or local image features can be detected in parallel, with each processor simultaneously accessing its neighbor and computing the appropriate function for its neighborhood. Meshes and several other …

Investigation Of Threaded Code, K. E. Graves, Paul D. Stigall

Computer Science Technical Reports

The design, structure and performance of threaded code are examined through the development of a threaded. code classification system and the modification of the threaded code technique used by a Forth programming language implementation. The classification system distinguishes threaded code designs by three elements: the interpreter, the code structure and the reference method to routines. Threaded code designs from the literature are described using the new classification scheme. The threaded code techniques of variable depth indirect threaded code and token indirect token threaded code are examined in a Forth programming language system on an INMOS IMS T222 transputer. Their design …

Investigation Of Threaded Code, K. E. Graves, Paul D. Stigall

Computer Science Technical Reports

The design, structure and performance of threaded code are examined through the development of a threaded. code classification system and the modification of the threaded code technique used by a Forth programming language implementation. The classification system distinguishes threaded code designs by three elements: the interpreter, the code structure and the reference method to routines. Threaded code designs from the literature are described using the new classification scheme. The threaded code techniques of variable depth indirect threaded code and token indirect token threaded code are examined in a Forth programming language system on an INMOS IMS T222 transputer. Their design …

Field-Equation Approximations And The Dynamics Of High-Gain Lasers, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Semiclassical models for laser-dynamics studies typically incorporate a derivative approximation that reduces the second-order wave equation for the electric field to a first-order equation. It is shown here that this approximation and further frequency approximations are not necessary and may lead to significant errors for some high-gain laser systems. A more exact analysis also reveals a partial decoupling of the electric and magnetic fields that occurs with fast transient phenomena. These ideas are illustrated in terms of well-known dynamical effects.

Study Of Joint Flexibility In Steel Frame Structures, Randy R. Frank

Opportunities for Undergraduate Research Experience Program (OURE)

Joint flexibility plays an important role in the distribution of strains and displacements in the frame structures of buildings, towers, automobiles, etc.. The objective of this project is to study the effect of flexibility (or rigidity) of two simple mechanical joints in frame structures on the stress and displacement distributions, using both experimental and analytical methods. Three welded and three bolted samples were fabricated using A-36 low carbon steel in a two column and horizontal crossmember (table) arrangement. This arrangement allows for both shear forces and axial forces in the joint. From a three element rectangular rosette strain gage attached …

Identity Authentication Based On Keystroke Latencies Using Neural Networks, Angela Lammers, Sharon Langenfeld

Opportunities for Undergraduate Research Experience Program (OURE)

Most computer security systems verify the identity of a user through objects in the user's possession such as keys or magnetic cards, or through knowledge the user has, such as a password or PIN number. There are, however, two other methods of user verification, which have as yet received little or no attention. There has been some work done on the third method, recognition of physiological patterns (such as finger prints, retinal patterns, or voice patterns), but this work has been limited and requires expensive hardware to implement. The final method of user verification is through actions such as signature …

A Computer Simulation Of The Umr Reactor, H. Allen Wilkins

Opportunities for Undergraduate Research Experience Program (OURE)

The Opportunities for Undergraduate Research project entitled, "A Computer Simulation of the UMR Reactor" had two goals. To produce a reactor simulation to be used in creating an artificial intelligence based reactor simulation for the UMR Nuclear Reactor and to produce a means of teaching students the fundamentals of reactor operations.

The primary purpose was to create a program which would simulate all the situations one would encounter in actual reactor operation. With the simulator the artificial intelligence system could be thoroughly tested before use with actual reactor data.

This same simulator would be used as a teaching aid for …

The Detection And Quantification Of Atrophic Rhinitis Using Ditigal Image Processing Techniques, Timothy Mussman

Opportunities for Undergraduate Research Experience Program (OURE)

This project focuses its attention on the detection and quantification of Atrophic Rhinitis (A.R.), a disease prevalent in pigs. A.R. causes some of the bony structure in a pig's snout to atrophy, which exposes the animal to other diseases that may effect its growth. It is studied by examining a cross section of the pig's snout. By comparing areas and perimeters of the nasal cavity to bony structures, or turbinates in the snout, one can determine the severity of the atrophy. Currently, the veterinarians diagnosis is based on a subjective analysis of the snout. The problem with this method is …

Phase Changes In Plasma‐Sprayed Zinc‐Nickel Ferrite, T. A. Dooling, Desmond C. Cook

Physics Faculty Publications

The magnetic and crystalline properties of a plasma‐sprayed coating of the microwave absorbing zinc‐nickel ferrite, (Zn_0.41Ni_0.59 )Fe₂O₄ have been studied at 300 K using the Mössbauer effect and x‐ray diffraction (XRD). Both techniques indicate that the plasma‐sprayed material separated into two phases. The first is a nickel‐rich phase with magnetic fields of 47.5 and 44.5 T at the tetrahedral and octahedral sites, respectively. The second is a zinc‐rich phase, zinc meta‐ferrite, having a small magnetic field of 4.2 T. The quadrupole splitting of this second phase is ΔE=0.34 mm s⁻¹, …

Monte Carlo Simulation Of Millimeter-Wave Gunn Effect Oscillators, Ramani Vaidyanathan

Electrical & Computer Engineering Theses & Dissertations

Monte Carlo simulations have been carried out to investigate the performance of microwave Gunn oscillators. Three separate aspects of the simulation problem have been comprehensively addressed in this work. First, the presence of an external circuit has been self-consistently incorporated into the calculations. The inclusion of the external circuit facilitates a study of the circuit controlled regime, and correctly models effects arising from the time dependent boundary conditions. Secondly, microscopic details of the electronic relaxation mechanisms which ultimately control the frequency response limits, have been taken into account through an iterative Monte Carlo-Poisson scheme. This procedure overcomes a potential shortcoming …

Q Improvement Of A 5.2 Ghz Te011 Cavity By Incorporating Y1Ba2Cu3O7-X, R. Joseph Leclear

Electrical & Computer Engineering Theses & Dissertations

Research is undertaken to apply high temperature superconducting material to improve the quality factor (Q) of a 5.2 GHz cylindrical resonant cavity. In particular, the approach is to electrophoretically deposit polycrystalline Y₁Ba₂Cu₃O_7-x (YBCO) on the conducting surface of the cavity cylinder. Spalling of the YBCO ceramic coating due to expansion and contraction of the cavity during sintering and testing is overcome by segmenting the cylinder. Results show that the Q of the cavity is increased over that of a copper cavity at temperatures below 60 K. At 20 K, improvement exceeds a factor …

An Erasable Optical Memory Based On Stimulated Electronic Transition Concept, James D. Satira

Electrical & Computer Engineering Theses & Dissertations

Erasable optical memory systems with a high storage density and a large data transfer rate are required for many real time data acquisition systems such as those placed aboard NASA's space born platforms. A new concept for erasable optical memory involving stimulated electronic transitions (SET) will meet these requirements. The SET concept useful in erasable optical storage systems was demonstrated in MgS and SrS doped with Eu and Sm. The optical properties of these materials were studied. The reading and writing wavelengths for these samples were determined to be 950 and 514 nm respectively. The peaks of the emission spectra …