Engineering Commons^™

Decentralized Optimal Control In Descriptor Systems, Hag-Yeon Park

Theses

Application of Matrix Minimum Principle to a linear decentralized optimal control in descriptor systems is studied in this thesis. Linear-quadratic index of performance with Gaussian initial state is considered. The necessary and sufficient conditions for optimality are derived

An additional constraint is imposed such that the controllers are linear function of output y(t) rather than of the state vector x(t). The optimal gain matrix G_i^* is then specified by the necessary conditions.

Two examples are developed to illustrate the concept.

Passive Radiosonde Transducer Design For Remote Pressure Sensing Applications, Yang Gao

Theses

Intracranial pressure can be measured to accuracies within 1 milliTorr using passive microtransponders that are micromachined using silicon as a base technology. These microtransponders can operate with either a dual-oscillator or a phase-locked loop frequency scanned control system.

The current work describes the design of a totally implantable microsensor for biomedical applications with the aim to monitor and measure the epidural intracranial pressure . The implanting microsensor is basically an RLC device in which capacitance varies with fluid pressure. The resonant frequency of RLC Series connected device varies with chemically etched diaphragm electrode spacing and thereby measures the variations with …

A Distributed Network Architecture For Video-On-Demand, Ge Dai

Theses

The objective of this thesis is to design a distributed network architecture that provides video - on - demand services to public subscribers. This architecture is proposed as an alternative to a centralized video service system. The latter system is currently being developed by Oracle Corporation and NCube Corporation.

A simulator is developed to compare the performance of both the distributed and centralized video server architectures. Moreover, an estimate of the cost of both systems is derived using current price data.

It is shown that the distributed video server architecture offers a better cost / performance trade-off than the centralized …

Artificial Dielectrics : Characteristics At Low And Microwave Frequencies, Nitish Agrawal

Theses

Artificial Dielectrics have been characterized using transmission line and s- parameter measurements. The complex dielectric constant and loss of graphite filled and non-poled piezoelectric-aggregate (Polyvinylidene Fluoride, PVDF) filled plastic (PMMA) has been characterized at low (1kHz-10kHz range, i.e., the VLF, very low frequency, range) and microwave frequencies. The average diameter diameter of graphite particles used was thirty microns. Measurements were performed on very fine graphite (one micron diameter grains) and 30 micron sized grains for comparison purposes. Fine grain graphite particles exhibited a, larger real dielectric constant, probably owing to a larger dipole effect. The dielectric constant characterization has also …

Processor Allocation For Partitionable Multiprocessor Systems, Nicholaos C. Antoniou

Theses

The processor allocation problem in an n-dimensional hypercube multipro-cessor is similar to the conventional memory allocation problem. The main objective is to maximize the utilization of available resources as well as minimize the inherent system fragmentation. In this thesis, a new processor allocation strategy is proposed, and compared with the existing strategies, such as, the Buddy strategy, the Single Gray Code strategy (SGC), the Multiple Gray Code (MGC), and the Maximal Set of Subcubes (MSS). We will show that our proposed processor allocation strategy outperforms the existing strategies, by having the advantage of being able to allocate unused processors to …

An Adaptive Correlator Receiver For Combined Suppression Of Co-Channel Interference And Narrow-Band Jammers In A Slowly Fading Channel, Raymond Carbone

Theses

This work deals with the adaptive correlation of a direct sequence spread spectrum signal in the presence of narrow-band, multipath and multiple user interference. The Least Mean Square and Recursive Least Square algorithms are employed for the adaptive convergence of the correlator receiver to minimize the mean squared error.

The performance of the adaptive correlator is compared with the matched filter correlator receiver and the conventional prediction filter for the suppression of narrow-band interference by calculating the bit error probability rate. The adaptive correlator is also compared with the RAKE receiver for multipath suppression and compared to the decorelating detector …

Data Broadcasting And Reduction, Prefix Computation, And Sorting On Reduced Hypercube (Rh) Parallel Computers, Arup Mukherjee

Theses

The binary hypercube parallel computer has been very popular due to its rich interconnection structure and small average internode distance which allow the efficient embedding of frequently used topologies. Communication patterns of many parallel algorithms also match the hypercube topology. The hypercube has high VLSI complexity. however. due to the logarithmic increase in the number of connections to each node with the increase in the number of dimensions of the hypercube. The reduced hypercube (RH) interconnection network. which is obtained by a uniform reduction in the number of links for each hypercube node. yields lower-complexity interconnection networks when compared to …

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 …

Influences Of Cardiac And Respiratory Parameters On Heart Rate Variability, Melissa Leifer

Theses

Heart rate variability is a result of variation in the activity of the sympathetic and parasympathetic nervous systems. Methods have been developed to determine the level of parasympathetic activity by observing the heart rate variability spectrum. Most of the previously published research uses only level of parasympathetic activity and respiratory rate to draw conclusions about the interactions of the autonomic nervous system with physiological parameters. In order to gain a complete understanding of the autonomic nervous system and the mechanisms responsible for heart rate variability, respiratory volume, cardiac variables and pulmonary variables need to be considered. In addition, amount of …

Cebus Demonstration System, Liang-Chuang Chen

Theses

A CEBus demonstration system is constructed and applied to aspects of home automation security. Two M68HC16Z1 evaluation boards are used as CEBus nodes. Two CEBus spread spectrum power line modems (SSC PLCEMS) interconnect the nodes. An SSC PLCEMS handles all spread spectrum signal generation and reception.

The application programs in the two boards are written in assembly language based upon CAL (Common Application Language), a CEBus standard.

The standard CEBus frame format and FCS (Frame Check Sequence) are implemented by software in the Data Link Layer. Encoding and decoding binary information into UST format are implemented in the Physical Layer. …

Control Of Smart Structure Using Adaptive Dither, Tian Hong

Theses

In this thesis, a mathematical model of a piezoelectric stack actuator is presented to describe its voltage versus displacement hysteresis characteristices. This model can accommodate a wide range of piezoelectric materials, including the PZT (lead zirconate-lead titanate) type which is most popular in industrial applications.

Besides describing the conventional "single-loop" hysteresis, this model also accounts for the off-axis minor loops by augmenting the algorithm with loop indexing.

It is shown that the PZT hysteresis possesses certain "weak scalability" that enables the use of spectral analysis to measure the level of nonlinearity.

After a suitable mathematical model has been obtained, a …

Cad Study Of Linear Tapered Slot Antenna, Anthony W. Kwan

Theses

Linear Tapered Slot Antenna (LTSA) is an attractive candidate as a radiating element in frequency scanning arrays. LTSA element backed by a rectangular cavity had been investigated and is proven to posses various physical design parameters suitable to optimize its performance. This study is focused on the feed position variation to optimize the performance while maximum of the current density variation is maintained in the slot region. It was observed that if the stub base of the microstrip feed structure is located in the middle of the slot region, current maximum can be obtained within the slot region at the …

Characterization Of Lightning Induced Voltages On Overhead Power Lines, Wen-Ta Hsiao

Theses

The transient voltage surge caused by lightning is the major source contributed to the disturbance on power systems. The calculation of induced voltages, which is the propagated voltage surge on overhead power lines due to indirect lightning strokes, has been the subject of theoretical and experimental studies. The objective of this research is to develop a comprehensive numerical method to study the induced voltages on an overhead power line caused by a lightning return stroke with arbitrary shapes, for examples inclined lightning, zigzag lightning, etc.

A finite-length lightning channel of any direction in 3-D space has been modelled and closed-form …

Multi-Disk Subsystem Organizations For Very Large Databases, Zhiyi Huang

Theses

This thesis investigates efficient mappings of very large databases with non-uniform access to its data. to a. multi-disk subsystem.

Two algorithms are developed to distribute the database across multiple disks, possibly with replication, in order to minimize latency and maximize throughput. These algorithms are compared with respect to the amount of replication overhead incurred to achieve desired throughput.

A simulator is developed to simulate these two mapping algorithms and investigate the efficiency of these two mappings.

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 …

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 …

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 …

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 …

A Novel Beam-Assisted Thickness Measurement Technique For Nanostructures, Luis Manual Casas

Theses

A novel method for measuring thickness of thin films has been developed. This method is straightforward, quickly accomplished, and offers resolution of device layers approaching that given by transmission electron microscopy. Ion beam bombardment of a multi-layer structure forms a crater in which the crater sidewalls are beveled at a very shallow angle, revealing various layers within the sample at a high degree of magnification. Beveled film thicknesses are measured by scanning Auger electron spectroscopy. Depth profilometry is used to measure the shallow beveling angle. Through knowledge of the beveled layer thickness and the bevel angle, actual film thicknesses are …

Programmable Microstrip Dipole Antenna Design, Jing Zhu

Theses

The narrow bandwidth of microstrip dipole antennas is a major limitation for many applications. A method to increase the microstrip dipole antenna bandwidth is illustrated in this thesis. The proposed method utilizes micromechanical actuators to adjust the electrical length of the dipole antenna. The length change is realized by the activities of several microactuators arranged on both arms of the antenna. The radiation pattern and input impedance, as well as the microactuator mechanisms are detailed in this thesis. A programmable microstrip dipole antenna including the microactuators has been designed with the feedline taken into consideration. The fabrication techniques for this …

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 …

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 …

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 …

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 …

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 …

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.

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 …

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 …

Fast Point Pattern Matching By Heuristic And Stochastic Optimization Techniques, Ashish Agrawal

Theses

This work is concerned with one of the methodologies used in the final stages of machine vision: the matching of model point patterns to observed point patterns. Conventional search methods not only fail to arrive at the optimal match, but are also computationally expensive and time consuming. To arrive at the optimal pattern match, stochastic and heuristic optimization as the search technique, exploiting Simulated Annealing (SA), Evolutionary Programming (EP) and Mean Field Annealing (MFA), are explored in detail. A comparison of results obtained using SA versus "hill-climbing" and "exhaustive search" techniques, and results of EP are presented. The relative effectiveness …

Fabrication Of Micron-Sized Mirror/Cantilever Silicon Devices For Crosspoint Switching Arrays, Yasser A. Abdel-Aziez

Theses

This thesis describes the fabrication of micron-sized vertical mirrors at the end of horizontal cantilevers, that are electrostatically controlled. The mirrors, 40x 40 μm with thicknesses of 1.5-6 μm, were made by using the etch resistance to 40% KOH etchant of <111> planes and oxide stripes. The cantilever beams, 100 to 350 μm long and 0.44 to 0.81 μm thick, were fabricated using the etch resistance of heavily doped boron layers to 10% KOH at 50 °C. Two technologies to introduce the boron layers were investigated. The ion implantation approach was based on thick oxide/photoresist masking. A maximum doping of 2.5 …