Engineering Commons^™

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 …

Design And Implementation Of Fuzzy Logic Controller For A Process Control Application, Sujit S. Nerurkar

Theses

Many industrial applications of fuzzy logic control have been reported. This thesis studies and reports the problems associated with the Heat-exchanger temperature control via conventional PID control implemented with Programmable Logic Controllers (PLC) and provides an example of design and implementation of fuzzy logic controllers (FLC's) for a Heat exchanger in a Water for Injection (WFI) system.

After a basic FLC was designed and tested, it is shown how its rule base evolved to achieve superior performance by utilizing additional low-cost sensing information in the process and its environment. A method for the implementation of FLC's into the existing PLC …

Adaptive Notch Filter, Yuchen Huang

Dissertations and Theses

The thesis presents a new adaptive notch filter (ANF) algorithm that is more accurate and efficient and has a faster convergent rate than previous ANF algorithms. In 1985, Nehorai designed an infinite impulse response (UR) ANF algorithm that has many advantages over previous ANF algorithms. It requires a minimal number of parameters with constrained poles and zeros. It has higher stability and sharper notches than any ANF algorithm until now. Because of the special filter structure and the recursive prediction error (RPE) method, however, the algorithm is very sensitive to the initial estimate of the filter coefficient and its covariance. …

A Multi-Dimensional Model Of Passive Mesfets For Use In Non-Linear Microwave Signal Processing, Roger Dorval

Theses

A multi-dimensional model which accurately predicts device non-linearities over frequency and power has been developed for MESFETs used in a passive configuration in microwave signal processing applications.

Historically, MESFETs have been used in linear control applications as passive microwave switches and attenuators. More recently, MESFETs operated as passive elements have been employed as power-sensitive non-linear transfer function generators to produce limiters, phase shifters, and linearizers. These devices offer simplicity, high performance, and the opportunity for application in MMIC technology.

This thesis deals with a mapping of passive MESFET non-linear characteristics, and provides insight into the causes of non-linearity in MESFETs …

Synthesis Of Numerical Integrators For The Real-Time Digital Simulation Of Continuous Systems, Michael James Panzitta

Retrospective Theses and Dissertations

Real-time digital simulation is a powerful means for engineers and scientists in government, industry, and academia to perform research and training as well as serving as a basis for many commercial applications. Due to the special constraints imposed by digitally simulating continuous systems in real time, however, many of these systems either require costly high-speed components or are unable to provide suitable performance characteristics using affordable computers.

This dissertation describes a new technique for the synthesis of numerical integrators specifically designed for the real-time digital simulation of continuous systems. This methodology is based upon the fact that the state derivatives …

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 …

Information Processing Using Laser Speckle, Rathnakar Gopisetty

Masters Theses

"The random speckle intensity pattern, which is produced by the scattered optical field from a rough surface when illuminated, can be used as a carrier of information. A theoretical study is performed to use the speckle patterns for retrieving the information of various kinds of object motions. A mathematical model of speckle is developed and used to relate different speckle patterns at various intervals as the object is experiencing motion. Four different object motions, i.e., one dimensional perpendicular motion, axial motion, three-dimensional motion, and rotational motion of an object are analyzed. In each case an interference pattern is produced which …

Color Image Enhancement Using Both Chromatic And Luminance Components, George Eric Hague Ii

Retrospective Theses and Dissertations

A vast amount of work has been published regarding grayscale processing of digital images. Although some of this work has been adapted for color images, many of the resulting algorithms neglect the correlation that exists between the individual RGB color components. Consequently, they introduce color artifacts. Attempts have been made to decouple the RGB components through color space transformations that isolate the luminance from the chromatic information. Color image enhancement is then considered a two step process, where the luminance and the chromatic components are processed independently. However, the RGB color space only has a finite number of available colors, …

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 …

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 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 …

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 …

The Characteristics Of Motion And Time Study In Taiwan's Electronics Industry And Their Relationship To Business Size, Betty Chang

Dissertations and Theses @ UNI

This research was conducted to investigate the characteristics of motion and time study implementation in Taiwan's electronics industry, as perceived by industrial engineers, and the relationships of these perceptions to business sizes of the firms. The questionnaires were mailed to 252 industrial engineers in the general firms group. A total of 206 (81.75%) instruments were returned. The questionnaires were then mailed to another 15 industrial engineers in the highly productive firms group. All the instruments (100%) were returned from the highly productive firm group. Telephone interviews were later conducted with six selected highly productive electronics firms to investigate their successful …

Polarimetric Fiber Optic Weigh-In-Motion Sensor, Jieping Wang

Theses

During the past decade, the demand for new methods of measuring the weight of moving vehicles has grown substantially. In the 1980's, several techniques for weighing vehicles in motion were developed. However, they often suffer from high installation and maintenance costs as well as low accuracy. This thesis describes a new technique based on polarization preserving optical fibers. A fibercore HB600 Bow-Tie fiber with an initial beat length of 1.16 mm was employed in the present study. Sensor response is discussed in terms of the effects of force amplitudes and velocities on the calibration parameter T_f. T_{f …}