Engineering Commons^™

Adaptive Channel Equalization Techniques, Saied Razavilar

Masters Theses

Inter Symbol Interference (ISI) is a characteristic of band-limited communication channels that can severely degrade the digital communication system performance if not treated properly. Channel equalization techniques may be used to mitigate the effects of ISI in the system, thereby improving the system capacity and performance. In this thesis, the problem of Inter Symbol Interference caused by the nonlinear characteristics of band limited communication channels and adaptive equalization techniques to combat the effects of ISI are discussed. First, the analysis of ISI in a band limited communication channel using a concrete theoretical framework is presented. Next, various adaptive equalization techniques …

Fitness Landscape Analysis Of Discrete Constrained Optimization Problems, Sai Prasanna Ravichandran

Masters Theses

The exponentially large size of the solution space of typical optimization problems precludes the use of any deterministic approach to search for an optimal solution. A more efficient and efficacious approach is to use heuristic algorithms based on rules of thumb to guide the search process in the solution space. Associated with every solution in the space is a real number called fitness that signifies the quality of a solution. This space and the fitness values together form the fitness landscapes. Knowledge about the topology of these fitness landscapes is vital for any heuristic search operator to expedite the search …

Multi-Baseline Interferometric Sar For Iterative Height Estimation, Adam E. Robertson

Theses and Dissertations

Multiple SAR interferograms with judiciously selected height sensitivities can be iteratively combined to create a high accuracy digital elevation map. An initial height estimate is refined by iteratively using larger baselines to obtain a height estimation accuracy limited by the spatial decorrelation of the antenna baseline. Spatial filtering is used to reduce the propagation of errors for accurate height estimation. Images containing regions isolated by phase discontinuities, as often found in urban environments, can be resolved by this iterative multi-baseline technique. Computationally demanding and potentially unreliable phase unwrapping is not required to determine scene elevation using SAR inMultiple SAR interferograms …

Modeling And Simulation Of High-Field, High-Temperature Sic Devices, Sanjay Pathak

Electrical & Computer Engineering Theses & Dissertations

With superior properties such as a large band gap, high thermal conductivity, and large electron drift velocity, SiC is expected to give a new dimension to high power, high temperature electronic devices used in power applications, microwave circuits, and for the space and automobile industries. SiC possesses an inherent advantage over its other large bandgap competitors in terms of inherited processing and device technology from Si. However, there is inadequate understanding of SiC device and its parameters. Simple extrapolations from Si are known to be inadequate. The aim of this dissertation, therefore. is to produce better understanding of SiC devices …

Automatic Target Cueing Of Hyperspectral Image Data, Terry A. Wilson

Theses and Dissertations

Modern imaging sensors produce vast amounts data, overwhelming human analysts. One such sensor is the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) hyperspectral sensor. The AVIRIS sensor simultaneously collects data in 224 spectral bands that range from 0.4µm to 2.5µm in approximately 10nm increments, producing 224 images, each representing a single spectral band. Autonomous systems are required that can fuse "important" spectral bands and then classify regions of interest if all of this data is to be exploited. This dissertation presents a comprehensive solution that consists of a new physiologically motivated fusion algorithm and a novel Bayes optimal self-architecting classifier …

Automatic Analysis Of Electronic Drawings Using Neural Network, Yi Shi

Dissertations

Neural network technique has been found to be a powerful tool in pattern recognition. It captures associations or discovers regularities with a set of patterns, where the types, number of variables or diversity of the data are very great, the relationships between variables are vaguely understood, or the relationships are difficult to describe adequately with conventional approaches.

In this dissertation, which is related to the research and the system design aiming at recognizing the digital gate symbols and characters in electronic drawings, we have proposed: (1) A modified Kohonen neural network with a shift-invariant capability in pattern recognition; (2) An …

Adaptive Bootstrap Signal Separators For Bpsk/Qam-Modulated Wireless Cdma Systems In A Multipath Environment, Nico J.M. Van Waes

Dissertations

CDMA is an attractive multiple-access scheme, because of its potential capacity increase and its anti-multipath fading capability. For satisfactory performance, however, the effect of the "near-far" problem has to be resolved. This problem can be combated by using power-control, which, however, results in an overall reduction in communication ranges, and thus in a loss of capacity. Among other methods for mitigating the near-far problem is the use of decorrelating receivers, both of fixed type, which directly utilizes the cross-correlation of the users codes, and of adaptive type, which uses recursive algorithms that leads to signal decorrelation. Not to lessen the …

Telephone-Accessed Controller Using Cebus For Device Control Over Power Line, Gerald Aska

Theses

The CEBus standard has made it possible for devices developed by different manufacturers to communicate over the power line. Further, the standard allows analog adjustments of devices besides transmitting and receiving binary information. This Controller extends the distance from which these devices can be controlled.

To extend the distance of communication with a device, a telephone line interface was developed that allows the user to communicate with a CEBus device via the Controller. The Controller responses [sic] to Central Office signaling and opens its communication channel to allow the user to provide it with the commands by using the telephone …

An Information-Theoretical Approach To The Adaptive Segmentation And Classification Of The Sleeping Electroencephalogram, Russell James Clark

Wayne State University Dissertations

Sleep is not a single homogeneous state; it consists of several identifiable states. The states are identified by the electroencephalogram (EEG), electrooculogram, and the electromyogram. The most common classification method consists of six classes labeled: wake, stage 1 through 4, and stage REM. A fixed length of data, usually 20 or 30 second epochs, are analyzed and placed in one of the six categories. An all-nigh sleep recording consists of 900 to 1500 such epochs and the task of scoring a record is tedious. Additionally, much of the detail in the EEG is lost due to the size of the …

Global Positioning System (Gps) Receiver Design For Multipaths Mitigation, El-Sayed Abdel-Salam Gadallah

Theses and Dissertations

Multipath effects are a source of error degrading the accuracy of DGPS signal processing. The statistical models of multipath are determined by user location and, in addition are time varying. There is no unified statistical model for the multipath signal. Therefore the solution of the multipath problem using statistical models is difficult. This research introduces a new estimator that can detect the presence of multipath, can determine the unknown number of multipath components and can estimate multipath parameters in the GPS receiver (time delay and attenuation coefficients). Furthermore the multipath signal parameters are estimated at any instant of observation. The …

The Optimized Electrostatic Motor, Christopher Lee Rambin

Doctoral Dissertations

The most common means of electrically activated actuation is the electromagnetic motor. All electromagnetic motors have a low output to weight ratio and low energy efficiency. The motor's weight is due to the coils and magnets used to generate propulsion. The energy loss is mainly the result of Joule heating that is inherent with any current driven device. An electrostatic motor offers the potential of significantly less weight and higher energy efficiency. This lower weight characteristic is due to the epoxide material used to construct the major components of its propulsion unit. Greater efficiency results from the reduced Joule heating …

Fuzzy Logic Applied To System Control To Enhance Commercial Appliance Performance, Glenn Moffett

Doctoral Dissertations

The purpose of this research is to determine the usefulness of fuzzy logic and fuzzy control when applied to a commercial appliance. Fuzzy logic is a structured, model-free estimator that approximates a function through linguistic input/output associations. Fuzzy rule-based systems apply these methods to solve many types of "real-world" problems, especially where a system is difficult to model, is controlled by a human operator or expert, or where ambiguity or vagueness is common.

This dissertation presents fuzzy sets, fuzzy systems, and fuzzy control, with an example conveying the use of fuzzy control of a consumer product and an overview of …

The Cluster Multipole Algorithm For Far-Field Computations, Rakesh R. Patel

Electrical & Computer Engineering Theses & Dissertations

Computer simulations of N-body systems are beneficial to study the overall behavior of a number of physical systems in fields such as astrophysics, molecular dynamics, and computational fluid dynamics. A new approach for computer simulations of N-body systems is proposed in this research. The new algorithm is called the Cluster Multipole Algorithm (CMA). The goals of the new algorithm are to improve the applicability to non-point sources and to provide more control on the accuracy over current algorithms. The algorithm is targeted to applications that do not require rebuilding the data structure about the system every time step due to …

Microhollow Cathode Discharge Excimer Lamps, Ahmed El-Habachi

Electrical & Computer Engineering Theses & Dissertations

Microhollow cathode discharges are non-thermal discharges of such small sizes that thermalization of the electrons is prevented. By reducing the diameter of the cathode opening in these discharge geometries to values on the order of 100 $\mu$m we were able to operate discharges in argon and xenon in a direct current mode up to atmospheric pressure. The large concentration of high electrons, in combination with high pressures favors three body processes such as excimer formation. This was confirmed by experiments in xenon and argon where emission of excimer radiation at 172 nm and 130 nm, respectively, was observed when the …

Effect Of Pulsed Electric Fields On Aquatic Nuisance Species, Amr Abou-Ghazala

Electrical & Computer Engineering Theses & Dissertations

Clinical and theoretical evidence indicate that electric fields have biological effects ranging from recoverable disturbance to mortality induction depending on the field parameters and time of exposure. In this thesis, the effect of electrical field in pulsed form on aquatic nuisance species is investigated. Pulse parameters in terms of amplitude, width, shape, and repetition rate that stimulate the species to desirable levels are to be defined. Applying the electrical pulses with appropriate parameters to stun aquatic nuisance species entering marine cooling systems will prevent it from attaching to pipe walls. The use of electrical fields to seek efficient, environmentally friendly, …

Representations, Approximations, And Algorithms For Mathematical Speech Processing, Laura R. Suzuki

Theses and Dissertations

Representing speech signals such that specific characteristics of speech are included is essential in many Air Force and DoD signal processing applications. A mathematical construct called a frame is presented which captures the important time-varying characteristic of speech. Roughly speaking, frames generalize the idea of an orthogonal basis in a Hilbert space, Specific spaces applicable to speech are L₂(R) and the Hardy spaces H_p(D) for p> 1 where D is the unit disk in the complex plane. Results are given for representations in the Hardy spaces involving Carleson's inequalities (and its extensions), …

Simulation Of The Hybrid Fuzzy-Boolean Finite State Machine (Hfb-Fsm), Hamed Shakouri

Masters Theses

Several models of fuzzy finite-state automata have been proposed in the literature. One model which benefits from the existing algorithms for designing Boolean finite-state machines, has been proposed by J. L. Grantner [8]. This model, which is called Hybrid Fuzzy-Boolean Finite State Machine (HFB-FSM), along with its algorithmic design procedure, can be used for implementing dynamic linguistic systems [7,8,13]. In this thesis we have developed a simulation program for the HFB-FSM model using C++ programming language. In order to simulate a HFB-FSM model, the user provides the information defining the system's behavior. Based on the algorithm proposed in [8], the …

Image Processing Based On A Fuzzy Logic Edge Detection Algorithm, Jamshid Khazaai

Masters Theses

One of the major problems in image processing is that of efficient edge detection. This is because the automated determination of an edge requires a subjective interpretation of just what the image author intended to be an edge. By training an edge determination algorithm to be sensitive to edges in a consistent manner, efficiency can be improved. This is the central idea of this thesis in which I define edge occurrences for the intensity (monochrome) images using fuzzy sets.

Edge characteristic functions are proposed for detecting edge pixels within a desired block of an (intensity and binary) image based on …

Trigonometric Transforms For Image Reconstruction, Thomas M. Foltz

Theses and Dissertations

This dissertation demonstrates how the symmetric convolution-multiplication property of discrete trigonometric transforms can be applied to traditional problems in image reconstruction with slightly better performance than Fourier techniques and increased savings in computational complexity for symmetric point spread functions. The fact that the discrete Fourier transform a circulant matrix provides an alternate way to derive the symmetric convolution-multiplication property for discrete trigonometric transforms. Derived in this manner, the symmetric convolution-multiplication property extends easily to multiple dimensions and generalizes to multidimensional asymmetric sequences. The symmetric convolution-multiplication property allows for linear filtering of degraded images via point-by-point multiplication in the transform domain …

Development And Packaging Of Microsystems Using Foundry Services, Jeffrey T. Butler

Theses and Dissertations

Micro-electro-mechanical systems (MEMS) are a new and rapidly growing field of research. Several advances to the MEMS state of the art were achieved through design and characterization of novel devices. Empirical and theoretical model of polysilicon thermal actuators were developed to understand their behavior. The most extensive investigation of the Multi-User MEMS Processes (MUMPs) polysilicon resistivity was also performed. The first published value for the thermal coefficient of resistivity (TCR) of the MUMPs Poly 1 layer was determined as 1.25 x 10(exp -3)/K. The sheet resistance of the MUMPs polysilicon layers was found to be dependent on linewidth due to …

Effects Of Clutter Height Distribution On Adaptive Clutter Erasure Performance, Kelce Steven Wilson

Theses and Dissertations

A new real beam interferometric processing technique, called Adaptive Clutter Erasure (ACE), is investigated for applicability to ground clutter suppression in airborne radar systems. By analysis and simulation, the viability of the ACE concept as a next generation clutter suppression technique is demonstrated to achieve performance enhancements commensurate with currently implemented techniques. Research results indicate the ACE concept provides a reliably consistent 10dB Signal-to-Clutter Ratio (SCR) advantage over the APG-63, an operational radar system used for baseline comparison. ACE system concept development and performance predictions are conducted in conformity with the physical and operational design parameters of the APG-63, namely …

High Amplitude Tracking Control, Joseph W. Mcnamee

Theses and Dissertations

The problem of tracking control in the face of high amplitude dynamic reference signals, hard state and control constraints, and open-loop unstable plants is investigated. Saturation effects mitigation is a current research topic, and a large body of literature exists which addresses this problem. However, with a few notable exceptions, little work has been accomplished which is applicable to the problem of high amplitude dynamic reference signal tracking in the face of hard state and control constraints, and open-loop unstable plants. Moreover, methods that do address the stated problem generally limit the exogenous reference signal to statically admissible values to …

Space-Time Reduced Rank Methods And Cfar Signal Detection Algorithms With Applications To Hprf Radar, Tareq F. Ayoub

Dissertations

In radar applications, the statistical properties (covariance matrix) of the interference are typically unknown a priori and are estimated from a dataset with limited sample support. Often, the limited sample support leads to numerically ill-conditioned radar detectors. Under such circumstances, classical interference cancellation methods such as sample matrix inversion (SMI) do not perform satisfactorily. In these cases, innovative reduced-rank space-time adaptive processing (STAP) techniques outperform full-rank techniques. The high pulse repetition frequency (HPRF) radar problem is analyzed and it is shown that it is in the class of adaptive radar with limited sample support. Reduced-rank methods are studied for the …

A Low-Cost High-Speed Twin-Prefetching Dsp-Based Shared-Memory System For Real-Time Image Processing Applications, Charalambos Stephanou Christou

Dissertations

This dissertation introduces, investigates, and evaluates a low-cost high-speed twin-prefetching DSP-based bus-interconnected shared-memory system for real-time image processing applications. The proposed architecture can effectively support 32 DSPs in contrast to a maximum of 4 DSPs supported by existing DSP-based bus- interconnected systems. This significant enhancement is achieved by introducing two small programmable fast memories (Twins) between the processor and the shared bus interconnect. While one memory is transferring data from/to the shared memory, the other is supplying the core processor with data. The elimination of the traditional direct linkage of the shared bus and processor data bus makes feasible the …

Performance Improvements In Wireless Cdma Communications Utilizing Adaptive Antenna Arrays, Weichen Ye

Dissertations

This dissertation studies applications of adaptive antenna arrays and space-time adaptive processing (STAP) in wireless code-division multiple-access (CDMA) communications. The work addresses three aspects of the CDMA communications problems: (I) near-far resistance, (2) reverse link, (3) forward link. In each case, adaptive arrays are applied and their performance is investigated.

The near-far effect is a well known problem which affects the reverse link of CDMA communication systems. The near-far resistance of STAP is analyzed for two processing methods: maximal ratio combining and optimum combining. It. is shown that while maximal ratio combining is not near-far resistant, optimum combining is near-far …

Petri Net Modeling And Performance Analysis Of Can Fieldbus, Ji-Qiong Zhou

Theses

The CAN FB (Controller Area Network FieldBus) has been in existence for ten years. It supports automated manufacturing and process control environments to interconnect intelligent devices such as valves, sensors, and actuators. CAN FieldBus has a high bit rate and the ability to detect errors. It is immune to noise and resistant to shock, vibration, and heat. Two recently introduced mechanisms, Distributed Priority Queue (DPQ) and Priority Promotion (PP) enable CAN FieldBus networks to share out the system bandwidth and grant ail upper bound on the transmission times so as to meet the requirements in real-time communications. Modeling and analysis …

Radiative Properties Of Silicon, Anamika Patel

Theses

The objective of this thesis was 1) to study the radiative properties of silicon in the wavelength range of 1 to 20 microns and temperature range of 30 to 1000°C for the development of a multi-wavelength pyrometer 2) to develop a [sic] methodologies for deconvolution of the measured optical properties to yield fundamental optical constants of bulk materials. A novel spectral emissometer has been utilized for measurement of the temperature dependent radiative properties of silicon. The temperature determination capability of the emissometer was tested and verified using a standard thermocouple embedded in a silicon wafer. The temperature measurement accuracy, with …

Collaborative Filtering In Tv Recommender, Elizabeth Podberezniak

Theses

The thesis describes different types of collaborative filtering methods to filter information from the large amount available and presents examples of such systems in different domains. It focuses on automated collaborative filtering to generate personalized recommendation of information.

Different variations of the automated collaborative filtering scheme are developed and analyzed in the thesis. An additional adjustment of the predicted score is implemented in order to improve precision of the recommendation. Different combinations of parameters are analyzed to maximize system effectiveness.

The data for the analysis was gathered through TV Recommender, a World Wide Web system developed for the thesis. The …

Design, Fabrication And Characterization Of Silicon Microlenses For Ir-Ccd Image Sensors, Dhiren Pattnaik

Theses

There is a growing trend in the study of Focal Plane Arrays(FPAs) of very small microlenses, used for a wide variety of imaging and sensing applications, to increase optical efficiency. Present day sensor technology might take a different direction altogether with the development of compact, high quality, high resolution imaging microlenses, which could make the fill factor >90%. A method to increase light sensitivity of Interline Transfer(IT) type image sensors is to position microlens FPAs on top of the image sensors. FPAs are structures of small lenses which focus the incoming light on the photo sensitive part of the image …

Investigation Of Pathophysiologic Trends In Caucasian And Afro-American Hypertensives By Means Of Heart Rate Variability Recording During Upright Tilt-Table Testing, Jose F. Torrealba

Theses

The incidence of hypertension is more prevalent among the Afro-American population than the Caucasians and there is not a satisfactory explanation for this discrepancy.

Heart Rate Variability (HRV) has been demonstrated to reflect the relative activities of the sympathetic (SMP) and parasympathetic (PSMP) divisions of the autonomic nervous system (ANS).

This study consisted in comparing the HRV, as well as the blood pressure (BP) of four different groups during up-right tilt table testing. The subjects were grouped by age, gender, race and health condition. Analysis in time and frequency domain was applied to the data. In the frequency domain, the …