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University of Texas at Arlington

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2006

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Probabilistic Localization Of Mobile Ad Hoc Networks, Rui Huang Dec 2006

Probabilistic Localization Of Mobile Ad Hoc Networks, Rui Huang

Computer Science and Engineering Dissertations

The mobile ad hoc network localization problem deals with estimating the physical location of the nodes that do not have a direct way (e.g., GPS) to determine their own locations. Being an enabling technology that is considered essential to the success of the future implementation of ad hoc networks in the real world, localization is a fundamental problem that needs to be solved with the best possible accuracy and efficiency. For this research, we study the localization problem in its various incarnations such as localization through static beacons, mobile beacons, dynamically deployed beacons and link longevity estimation based on relative …

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Complementing Current Active Queue Management Schemes With Rechoke And Receiver-Window Modification (Rwm), Visvasuresh Govindaswamy Dec 2006

Complementing Current Active Queue Management Schemes With Rechoke And Receiver-Window Modification (Rwm), Visvasuresh Govindaswamy

Computer Science and Engineering Dissertations

Explicit Congestion Notification (ECN) and Active Queue Management (AQM) schemes have been proposed for present-day TCP/IP networks to better manage network congestion. ECN enabled AQMs were shown to have a promising advantage over existing drop-tail queues. However, when implemented, they were susceptible to the following problems: 1) the timeout mechanism or the duration of the reception of three duplicate acknowledgements (ACKs), due to early-dropped packets by these AQMs, delays the response time of TCP (in reducing the offered rate) 2) using ECN with these AQMs has its downsides: i) its messages may get delayed or dropped due to congestion in …

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Identifying Individual Eurasian Otters (Lutra Lutra) Based On Measurements Of Their Footprints Standardization Of The Method And Its Potential For Censusing And Monitoring Wild Otter Populations, Jitka Vetrovcova Dec 2006

Identifying Individual Eurasian Otters (Lutra Lutra) Based On Measurements Of Their Footprints Standardization Of The Method And Its Potential For Censusing And Monitoring Wild Otter Populations, Jitka Vetrovcova

Biology Theses

A method for identifying individual Eurasian otters (Lutra lutra L.) from measurements of their footprints was first tested by performing experiments with captive animals. Digital photographs were taken of imprints in mud of all paws of 12 known individuals. Using customized software, 131 distance, angle, and proportion measurements were generated and subjected to discriminant and canonical analyses. The stepwise procedures of discrimination were the principal statistical analyses used. Analyzing each foot separately while using all available imprints yielded 86-93% correct classification and 59-77% Jacknife cross-validation. The efficiency of these analyses was not significantly affected by randomly reducing the number of …

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A Study Of Factors Affecting Scale Roughness In The Western Diamondback Rattlesnake (Crotalus Atrox), Amber Gail Skach Dec 2006

A Study Of Factors Affecting Scale Roughness In The Western Diamondback Rattlesnake (Crotalus Atrox), Amber Gail Skach

Biology Theses

Reptilian scales are very complex with patterns across their surface like a human fingerprint. These patterns are species specific, but there has been no way to quantify differences. A new technique using the confocal microscope allows measurement of the roughness of a surface. The roughness of the scales of Crotalus atrox were measured and compared with factors such as sex, age, clade, and various environmental variables to determine if this technique may be useful in determining species. The results found that the roughness of a scale decreased as the snake aged, and was significantly different between the two clades; the …

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Geographic Variation In The Morphometrics Of Emydoide Blandingii, Maggie M. Camperlengo Dec 2006

Geographic Variation In The Morphometrics Of Emydoide Blandingii, Maggie M. Camperlengo

Biology Theses

Morphometric measurements were taken from museum specimens Emydoidea blandingii. Samples were taken from Michigan, Wisconsin, Illinois, Iowa, Nebraska, New York and Minnesota as well as from Ontario, Canada. Populations of this species have become increasingly fragmented and isolated during the past century due primarily to the urbanization of North America which has included increased road related fatalities and habitat destruction. An examination of physical characteristics was conducted to determine if morphometric analysis could indicate differences among the various populations. Twenty-eight measurements were made and compared to detect physical distinctions between populations. Individuals were then classified geographically based on east (C), …

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Does An Exotic Invasive Grass Facilitate The Invasion Of A Woody Species Into Remnant Prairies?: A Study Of The Native, Prosopis Glandulosa And The Alien, Sorghum Halapense, Amie E. Treuer Dec 2006

Does An Exotic Invasive Grass Facilitate The Invasion Of A Woody Species Into Remnant Prairies?: A Study Of The Native, Prosopis Glandulosa And The Alien, Sorghum Halapense, Amie E. Treuer

Biology Theses

The native tree, Prosopis glandulosa, and the exotic grass, Sorghum halepense, have been invading native prairies in the Southwest U.S. since the 1800s. My objectives were to determine if S. halepense was driving shifts in the abiotic and biotic structure of a native prairie and in doing so facilitating the invasion of P. glandulosa. Both field and greenhouse experiments were established to address these objectives. The presence of S. halepense lowered light and increased soil N in the field relative to the native prairie. Plant species diversity and the number of woody species were higher in an invaded zone than …

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Novel Functions And Physiological Significance Of Ral Interacting Protein - Rlip76 In In Vitro And In Vivo Models, Ewa L. Zajac Dec 2006

Novel Functions And Physiological Significance Of Ral Interacting Protein - Rlip76 In In Vitro And In Vivo Models, Ewa L. Zajac

Chemistry & Biochemistry Dissertations

This dissertation is divided into four parts. The first part is an introduction of energy dependent xenobiotic transporters and their relevance in multidrug resistance. However, the main focuse is the description of RLIP76 protein, non-ABC transporter, which it the most efficient transporter of glutathione conjugates and anti-cancer drugs. The second part describes materials and methods that were used in two investigated projects. The third part explains the correlation of RLIP76 with signaling protein POB1 and an involvement of these two proteins in apoptosis of lung cancer cells. The effect of recombinant POB1 and its deletion mutant POB11-512, on transport activity …

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The Formation And Obduction Of Ophiolites Since The Late Precambrian, Stacey Metzler Dec 2006

The Formation And Obduction Of Ophiolites Since The Late Precambrian, Stacey Metzler

Earth & Environmental Sciences Theses

Ophiolite formation and emplacement has been episodic since the Late Precambrian. This research study examines ophiolites that formed during the Cenozoic, Mesozoic, Paleozoic and Late Precambrian. The ophiolites were plotted on paleogeographic reconstructions using PALEOMAP Project maps, and the ophiolite localities were analyzed by their temporal distribution in relation to the tectonic framework in which they were emplaced. The ophiolites appear to show episodic events linked to global plate reorganization. These episodes coincide with collisional events from the supercontinents of Gondwana and Pangea. The primary mechanisms of formation and emplacement proved to be mid-ocean ridge systems and back arc basins …

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The Power Of Ostracism: Can Personality Influence Reactions To Social Exclusion?, Amy Marie Waldrip Dec 2006

The Power Of Ostracism: Can Personality Influence Reactions To Social Exclusion?, Amy Marie Waldrip

Psychology Dissertations

Ostracism, also labeled social exclusion, is seen by researchers and lay persons alike as one of the more socially painful events that is an inevitable part of life. Moreover, many theorists (e.g., Zadro, Williams, and Richardson, 2004) believe that no one is immune to the negative power of ostracism and that this sensitivity to ostracism is both primitive and adaptive. The primary focus of this dissertation was to examine how personality might moderate this sensitivity to social exclusion. In the first phase of the study, college students (N = 145) came to the laboratory in small groups to complete self-descriptions …

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Calix[4]Arene-Based Synthetic Nanotubes, Voltaire Guanlao Organo Dec 2006

Calix[4]Arene-Based Synthetic Nanotubes, Voltaire Guanlao Organo

Chemistry & Biochemistry Dissertations

Nanoscale science and technology represents a tremendous opportunity to gain unprecedented insight into the unique phenomena that exists at the nanometer scale, and to use that knowledge to develop materials and devices with novel characteristics. This dissertation explores the unique properties of calix[4]arene-based synthetic nanotubes, the process of filling and characteristics of materials confined in one dimension. Chapter 1 provides an overview of recently developed nanoscale materials, particularly single-walled carbon nanotubes and their ability to encapsulate materials in a one-dimensional configuration. Molecules inside carbon nanotubes are reported to exhibit structural and dynamic properties that are not observed in the bulk. …

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Effects Of Temperature Gradients On Transverse Oscillations Of Solar Magnetic Flux Tubes, Shilpa Subramaniam Dec 2006

Effects Of Temperature Gradients On Transverse Oscillations Of Solar Magnetic Flux Tubes, Shilpa Subramaniam

Physics Theses

Solar magnetic flux tubes support three fundamental modes: longitudinal, transverse and torsional tube waves. Previous studies showed that the propagation of longitudinal and transverse waves along thin and isothermal magnetic flux tubes is affected by the cutoff frequency, which are global quantities that restricts the wave propagation to only those frequencies that are higher than the cutoff. It was also demonstrated that the tubes respond to freely propagating longitudinal and transverse tube waves by oscillating at the corresponding cutoff frequency. No cutoff frequency was found for torsional waves propagating along thin and isothermal magnetic flux tubes. Since the solar atmosphere …

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Perception Of Diversity, Niveditha Parthasarathy Dec 2006

Perception Of Diversity, Niveditha Parthasarathy

Psychology Theses

Two studies were conducted to examine effects of diversity on perception. The primary purpose of the first study was to see how people perceive diverse groups, how comfortable they are working in such groups, and how attracted they are to diverse groups. Results indicated that people prefer working with groups that represented their ethnicity (race-inclusion) and perceived such groups to be more attractive than groups that did not represent their ethnicity (race-exclusion). Also, White participants were more attracted to diverse groups and more willing to work in diverse groups than Black participants. Most importantly, the preference of race-inclusion pictures to …

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Les For Wing Tip Vortex Around An Airfoil, Jiangang Cai Dec 2006

Les For Wing Tip Vortex Around An Airfoil, Jiangang Cai

Mathematics Dissertations

The wing tip vortex is very important because of its effects on the noise generation, blade/vortex interactions on helicopter blades, propeller cavitations on ships, and other fields. The objective of this work is to use the numerical simulation with high order accuracy and high resolution to investigate the formation and the near field evolution of a wing tip vortex at high Reynolds number. The computational domain includes a rectangular half-wing with a NACA 0012 airfoil section, a rounded wing tip and the surrounding boundaries. The wing has an aspect ratio of 0.75. The angle of attack is 10 degrees. The …

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Re-Experiencing Social Versus Physical Pain And Its Influence On Self-Regulatory Reserve, Jennifer M. Knack Dec 2006

Re-Experiencing Social Versus Physical Pain And Its Influence On Self-Regulatory Reserve, Jennifer M. Knack

Psychology Theses

This study examined the influence of reliving social pain on current reports of pain, self-regulatory ability, and differences in reactions. Participants (N=137) completed personality measures in phase one. Days later, participants completed a mood measure and the Stroop. They were randomly assigned to recall a physical pain, social pain, possession loss, or Monday morning. Participants indicated current degree of pain, level of psychological needs, and current mood. Participants again completed the Stroop. The researcher then offered participants cookies, but noted there was not enough for other participants. Participants recalling social pain reported more pain and greater threatened belongingness and meaningful …

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Novel Intraocular Drug Delivery System For The Prevention Of Posterior Capsule Opacification, Brett Thomes Dec 2006

Novel Intraocular Drug Delivery System For The Prevention Of Posterior Capsule Opacification, Brett Thomes

Bioengineering Dissertations

Posterior capsule opacification (PCO) is a major complication associated with the implantation of intraocular lens (IOLs). Evidence suggests that PCO formation is caused by abnormal lens epithelial cell (LEC) migration/proliferation. We hypothesize that pharmacologic agents must target inflammatory cells in addition to LECs to inhibit PCO formation. To successfully target both inflammatory cells and LECs, a novel intraocular drug delivery system (DDS) was developed for implantation in the lens capsular bag. Such a system permits direct delivery of anti-inflammatory and anti-proliferative drugs in the lens capsule for extended periods of time resulting in reduced PCO formation. A lubricious polyurethane coating …

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School Responses To High-Stakes Testing, Mishuk Anwar Chowdhury Dec 2006

School Responses To High-Stakes Testing, Mishuk Anwar Chowdhury

Economics Theses

This paper analyzes school's responses to high stakes testing. Using a grade level panel dataset from Texas Assessment of Knowledge and Skills (TAKS) for reading and math tests for 2003 through 2006, to find schools responses to failure. I find that there is a tendency for schools to shift resources from subjects that they pass to subjects that they fail. I classify schools' responses as either substitution responses or scale responses. A school has a substitution response if, when it fails to meet the state's required passing rate threshold for one subject for one cohort of students, it shifts resources …

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Evidence Of Competition Between Law Schools, Naushaba Zaman Dec 2006

Evidence Of Competition Between Law Schools, Naushaba Zaman

Economics Theses

The purpose of this paper is to measure how competition affects tuition rates of law schools. I hypothesize that the tuition rates will go up as concentration of law schools increase. To examine how tuition varies with competition, I need to measure market structure. A variety of measures are available, such as C4, C8, and HHI; all of which have some relationship to the degree of competitiveness in an industry. I primarily use HHI as the concentration measure in this paper. I make two models for my thesis. In my first model I use a statewide measure of competition, assuming …

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Legitimate Strategies In Writing : Exploring Esol Learner Perspectives On Attribution, Danielle Elaine Plauche Dec 2006

Legitimate Strategies In Writing : Exploring Esol Learner Perspectives On Attribution, Danielle Elaine Plauche

Linguistics & TESOL Theses

In many academic institutions today, ESOL (English as a Second or Other Language) writers may incorporate background sources into their writing in ways unrecognized by their academic institutions, which could lead to these learners' academic success or failure. In recent years, researchers and teachers alike have sought to understand the ways ESOL writers understand and avoid plagiarism in many academic institutions. Yet there is little research which explores the perspectives of ESOL writers regarding strategies that are used to attribute authorship. The following study explores the strategies that eight ESOL writers in four different pre-academic proficiency levels use to attribute …

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Finite Element Modeling Of Carbon Nanotube Reinforced Polymer Composites And Evaluating Its Thermal Conductivities, Raghuram Basavanahalli Dec 2006

Finite Element Modeling Of Carbon Nanotube Reinforced Polymer Composites And Evaluating Its Thermal Conductivities, Raghuram Basavanahalli

Mechanical and Aerospace Engineering Theses

High thermal conductivity of carbon nanotubes has motivated us to study and understand the thermal mechanisms in nanocomposites. Though several theoretical models predict a high thermal conductivity for CNT reinforced polymer composites, the experimental validation are not so encouraging. A finite element model of MWNT reinforced nanocomposite is developed based on continuum mechanics approach. The finite element model is a representative volume element (RVE) with single MWNT inclusion. The inclusion is modeled based on the continuum model of MWNT as effective solid fiber [22].The interface resistance between the nanotube and the matrix material is modeled using thermal contact elements. The …

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Design And Optimization Of Heat Spreaders And Selection Of Fan In Laptop, Kranthi Kumar Manne Sambaiah Dec 2006

Design And Optimization Of Heat Spreaders And Selection Of Fan In Laptop, Kranthi Kumar Manne Sambaiah

Mechanical and Aerospace Engineering Theses

Technical advancements lead to the need for faster processors and reduced sizes in electronic systems. The urge for faster and compact systems leads to two major problems. Firstly over heating of chips which degrade the chip performance and secondly formation of heat spots on the surface which makes the user uncomfortable. Thermal management engineers, as a result have a major challenge in improving the cooling systems. In this research project simulation using the thermal modeling tool selected is Icepak. The prototype model of the laptop is designed, boundary conditions are applied and analysis is done. The results so obtained in …

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Structural Analysis Of Fiber Reinforced Composite Materials, Cesar Augusto Rojas Dec 2006

Structural Analysis Of Fiber Reinforced Composite Materials, Cesar Augusto Rojas

Mechanical and Aerospace Engineering Theses

A study of fiber reinforced composite structures is conducted .This study includes laminate analysis, analysis of laminated composite beams and parametric study of composite beams. Finite element analysis for each beam model is conducted to verify the results obtained by analytical model. The analysis of the laminated beams in this study covers: 1. beam with a solid rectangular cross-section subjected to a transverse load 2. beam with a I-section under bending 3. beam with a squared tubular section under bending 4. beam with truss section under bending One of the principal purposes of this thesis is to create a user …

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Enhancement Of Pool Boiling Heat Transfer Using Thermally-Conductive Microporous Coating Techniques, Joo Han Kim Dec 2006

Enhancement Of Pool Boiling Heat Transfer Using Thermally-Conductive Microporous Coating Techniques, Joo Han Kim

Mechanical and Aerospace Engineering Dissertations

The present research is an experimental study of the enhancement of boiling heat transfer using microporous coating techniques. The current research is divided into four major phases. During the first phase, the effects of different metal particle sizes in the coating compound for thermally non-conductive microporous coating on pool boiling performance of refrigerants and water are investigated. The test surfaces, solid copper blocks with 1-cm² base, were tested at atmospheric pressure in saturated FC-72, R-123, and water. Results showed that the surface treatment by non-conductive microporous coating significantly enhanced both nucleate boiling and critical heat flux of all three refrigerants. …

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Optimization Of The Tool Path In A Robotic Environment, Mukund Venkatachari Narasimhan Dec 2006

Optimization Of The Tool Path In A Robotic Environment, Mukund Venkatachari Narasimhan

Mechanical and Aerospace Engineering Dissertations

The rising costs and demand coupled with shrinking energy generating resources has triggered the need for optimum use of energy resources, minimizing the overhead costs and maximizing the profits. Robots have been long touted as a fit replacement of human labor force in manufacturing sectors. Slowly there is increased presence of robots in automobile and electronic industries. Typically they are used for welding, painting, ironing, assembly, pick and place, inspection, and testing. Mass production, fulfilling the ever increasing demand, can be accomplished by robots because of their precision, speed of operation and high endurance capabilities. This dissertation comprises of two …

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Computer-Aided Patient Specific Treatment Planning Of Cryosurgery For Breast Cancer, Junkyu Jung Dec 2006

Computer-Aided Patient Specific Treatment Planning Of Cryosurgery For Breast Cancer, Junkyu Jung

Mechanical and Aerospace Engineering Theses

Cryosurgery, which is to destroy tumors by use of localized freezing, is an emerging treatment modality for breast cancer as the size of detectable tumor becomes smaller due to more frequent use of various diagnostic imaging including MRI, CT and mammogram. Although general surgical guideline has been developed and its effectiveness has been demonstrated, cryosurgical protocol should be adjusted for a given patient to accommodate patient-specific variations including tumor size, location and geometry of patient's breast. In this study, a computerized treatment planning tool was developed to aid surgeons to determine surgical parameters considering patient specific diagnostic information. This tool …

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Freezing-Induced Microstructural Changes Of Collagen Scaffolds, Jeffrey David Miller Dec 2006

Freezing-Induced Microstructural Changes Of Collagen Scaffolds, Jeffrey David Miller

Mechanical and Aerospace Engineering Theses

Understanding the effects of freezing on the functional properties of tissues is critical to cryopreservation of native and artificial tissues, and prognosis after cryotherapies. Although investigations have been performed to correlate macroscopic properties such as mechanical properties with freezing parameters, the effects are typically tissue-type dependent and no physical understanding is available to explain these effects. Since the mechanical and optical properties of a tissue are based on the characteristics of its extracellular matrix (ECM), understanding and quantifying these changes could assist in predicting the response a tissue will have to freezing under different circumstances. In this study, the microstructural …

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The Development Of A Design Ontology For Products And Processes, Md Baniamin Sarder Dec 2006

The Development Of A Design Ontology For Products And Processes, Md Baniamin Sarder

Industrial, Manufacturing, and Systems Engineering Dissertations

This research develops a methodology called, Design Knowledge Acquisition Process (DKAP) for creating ontology of product and process design using IDEF5 and to develop a consistency matrix for checking accuracy of captured information. It constructs an ontology of a generic product and process design using the developed DKAP methodology. Designing products and processes is very challenging and vital for manufacturing enterprises to stay in the competitive market. Manufacturers want to launch their products in the market as quickly as possible while satisfying their customers in terms of quality, cost and delivery. In order to lunch the products early and/or to …

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An Analytical Performance Management Framework Enabiling Enterprise Strategy Management, Amr Abu-Suleiman Dec 2006

An Analytical Performance Management Framework Enabiling Enterprise Strategy Management, Amr Abu-Suleiman

Industrial, Manufacturing, and Systems Engineering Dissertations

Performance management has gained noticeable interest from both researchers and executive in the past two decades. Financial measures are no longer a primary emphasis for researchers and executives. One of the most popular performance management methodologies is the Balanced Scorecard. The Balanced Scorecard framework facilitates translating strategy into objectives and initiatives across four perspectives. These perspectives are financial, customer, internal processes, and learning and growth. The second component of the balanced scorecard is strategy maps. Strategy maps outline the cause and effect between the four perspectives, and illustrate the value creation process through transforming leading indicators (operational measures) into lagging …

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Scalar Equilibria For N-Person Games, Narakorn Engsuwan Dec 2006

Scalar Equilibria For N-Person Games, Narakorn Engsuwan

Industrial, Manufacturing, and Systems Engineering Dissertations

In this dissertation we develop a scalarization approach for one-shot, n-person games by defining the notion of Scalar Equilibria. We first show that existing solution concepts can be represented as Scalar Equlibria. For example, Regret, Disappointment, and Joint Equilibrium can be determined by defining Regret, Disappointment, and Joint Scalar Equilibria. These scalar equilibria are useful for finding pure strategies when pure Regret, Disappointment, and Joint Equilibria do not exist. Next, we present the Maximin Scalarization Equilibrium to yield maximin solution concept. In addition, we propose other Scalar Equilibria for various notions of rationality. The Aspiration Scalar Equilibrium is developed for …

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Neural Network Solution For Fixed-Final Time Optimal Control Of Nonlinear Systems, Tao Cheng Dec 2006

Neural Network Solution For Fixed-Final Time Optimal Control Of Nonlinear Systems, Tao Cheng

Electrical Engineering Dissertations

In this research, practical methods for the design of H2 and H-Infinity optimal state feedback controllers for unconstrained and constrained input systems are proposed. The dynamic programming principle is used along with special quasi-norms to derive the structure of both the saturated and optimal controllers in feedback strategy form. The resulting Hamilton-Jacobi-Bellman (HJB) and Hamilton-Jacobi-Isaacs (HJI) equations are derived respectively. Neural networks are used along with the least-squares method to solve the Hamilton-Jacobi differential equations in the H2 case, and the cost and disturbance in the H-Infinity case. The result is a neural network unconstrained or constrained feedback controller that …

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Generation Planning And Market Operation Strategies In The Southwest Power Pool Energy Imbalance Service Market, Kittipong Methaprayoon Dec 2006

Generation Planning And Market Operation Strategies In The Southwest Power Pool Energy Imbalance Service Market, Kittipong Methaprayoon

Electrical Engineering Dissertations

The transition of the Southwest Power Pool (SPP) from its traditional operation under tariff towards the new market environment has significant impact on the utilities in the SPP footprint, both in terms of planning and operations. The new market regulation creates the need for the utilities to reassess their planning strategy, primarily to ensure that operational decisions conform to the new market rules while remain profitable under the new operating regime. The utilities are referred to as Market Participants (MP) under the new market scheme. The new market environment will expose the MPs to a large amount of information with …

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