Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

University of Texas at Arlington

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 8011 - 8040 of 8661

Full-Text Articles in Entire DC Network

Nonlinear Finite Element-Based Investigation Of The Effect Of Bedding Thickness On Underground Pipe, Anupong Kararam Jul 2006

Nonlinear Finite Element-Based Investigation Of The Effect Of Bedding Thickness On Underground Pipe, Anupong Kararam

Civil Engineering Theses - Archive

The pipe-soil interaction is studied by using the finite element software, ABAQUS/CAE Version 6.5-1 as a symmetric model of embankment installation to study the effect of bedding property and thickness on pipe-soil interaction with increase in the height of fill. A three-dimensional finite element model (FEM) of the concrete pipe and surrounding soil is developed. The FEM is capable of simulating material, geometric, and contact nonlinearities which employs a nonlinear incremental solution algorithm. Several different element types and mesh size were tested to obtain the optimum converged mesh. These elements were eight-noded linear brick (C3D8R) and six-noded linear triangular prism …

Go to article

Web-Based Real-Time Monitoring System To Enhance The Participation Of An Industrial Power System In A Restructured Utility Industry, Shun-Hsien Huang Jul 2006

Web-Based Real-Time Monitoring System To Enhance The Participation Of An Industrial Power System In A Restructured Utility Industry, Shun-Hsien Huang

Electrical Engineering Dissertations - Archive

The opening of the Electric Reliability Council of Texas (ERCOT) grid to wholesale competition began in 1996 that initiated the first stage of deregulation in Texas. In order to relieve generation and transmission constraints, load reduction is considered as a form of available energy and spinning reserve. Afterward, power system becomes more dynamic and creates more opportunities for both electricity suppliers and consumers. Currently, both power supplier and demand consumer can participate in the energy and ancillary services (AS) markets to bid/offer for their energy, capacity, and demand in the ERCOT markets. In order to act as an effective market …

Go to article

An Emission Model For Lunar Regolith Surfaces Based On Matrix Doubling Method, Darshan Shrestha Jul 2006

An Emission Model For Lunar Regolith Surfaces Based On Matrix Doubling Method, Darshan Shrestha

Electrical Engineering Theses - Archive

An emission model based on Matrix Doubling Method is implemented for the calculation of emission signatures from the lunar regolith surfaces. The matrix doubling method is used to solve the radiative transfer equations which encompass the volume and surface scattering properties of the medium. The layer and surface are characterized by their corresponding phase matrices which contain adequate information on how the amplitude, phase and polarization of the incident Stokes vector change on being incident in that medium. Emissivity signatures are calculated by solving the transfer equations using matrix doubling method and taking these phase matrices as "boundary conditions". The …

Go to article

Connections: Library News For Library Staff Vol. 3, Issue 7, University Of Texas At Arlington Library Jul 2006

Connections: Library News For Library Staff Vol. 3, Issue 7, University Of Texas At Arlington Library

Connections: Library News for Library Staff

The purpose of Connections was to build community within UTA Library staff by reminding people of upcoming events and dates, introducing new staff members, celebrating a department's achievements, and writing about other items of interest.

Go to article

A Graph-Based Approach For Modeling And Indexing Video Data, Jeongkyu Lee Jun 2006

A Graph-Based Approach For Modeling And Indexing Video Data, Jeongkyu Lee

Computer Science and Engineering Dissertations - Archive

With the advances in electronic imaging, storage, networking and computing, the amount of digital video has grown tremendously. The proliferation of video data has led to significant amount of research on techniques and systems for efficient video database management. In particular, extensive research has been done on video data modeling to manage and organize the data that is semantically rich and complicated. However, the enormous amount of data size and its complexity have restricted the progress on video data modeling, indexing and retrieval. In order to get around the problems, we turn to a graph theoretical approach for video database. …

Go to article

Simulation Of Sensor Responses Of Advanced Security Systems, Janakiram Natarajan Jun 2006

Simulation Of Sensor Responses Of Advanced Security Systems, Janakiram Natarajan

Computer Science and Engineering Theses - Archive

Security systems are becoming an increasingly important area of research. Advanced security detection and surveillance systems that integrates a variety of detection mechanisms, like signals from different kinds of sensors, is expected to yield more accurate assessment than any one sensor analyzed individually. Designing and investigating these systems, to date, has relied primarily on physical deployments and experimentation. While the quality of the results from such efforts is excellent, the need to work with the physical systems directly imposes a substantial research impediment. One obvious possibility for widening the scope of what can be investigated is to employ simulation as …

Go to article

Exception Handling Using Class Diversity, Qizhi Ye Jun 2006

Exception Handling Using Class Diversity, Qizhi Ye

Computer Science and Engineering Theses - Archive

Software reliability has been received more and more attention not only in mission critical system but also in commercial software system. Developing robust software must consider faults caused by abnormal situations or exceptions. Although modern programming languages like Java and C++ provide sophisticated exception handling mechanisms for detecting and handling exceptions, many potential runtime exceptions are not caught and handled because runtime exceptions could occur anywhere and could be numerous in a typical program. If an uncaught runtime exception occurs during program execution, then the execution will terminate abnormally, resulting in a system crash. The thesis proposes a framework that …

Go to article

Connections: Library News For Library Staff Vol. 3, Issue 6, University Of Texas At Arlington Library Jun 2006

Connections: Library News For Library Staff Vol. 3, Issue 6, University Of Texas At Arlington Library

Connections: Library News for Library Staff

The purpose of Connections was to build community within UTA Library staff by reminding people of upcoming events and dates, introducing new staff members, celebrating a department's achievements, and writing about other items of interest.

Go to article

Arlington 130th Anniversary Bookmarks, Evelyn Barker Jun 2006

Arlington 130th Anniversary Bookmarks, Evelyn Barker

Information Literacy Resources-Archive

Bookmarks celebrating the 130th anniversary of the City of Arlington.

Go to article

Relative Clock Drift Rate Based Secure Time Synchronization For Wireless Sensor Networks, Jae Sung Choi May 2006

Relative Clock Drift Rate Based Secure Time Synchronization For Wireless Sensor Networks, Jae Sung Choi

Computer Science and Engineering Theses - Archive

Time synchronization is critical issue to many wireless sensor network applications such that target tracking, TDMA radio scheduling, and secure localization. However, the most of existing time synchronization algorithms in wireless sensor networks did not consider malicious attacks in hostile environments. In this thesis, we propose a Relative Clock Drift Rate Based Secure Time Synchronization (RSTS) schemes to address security problems. RSTS alleviates delay attacks and incorrect time stamp transmissions caused by external or internal malicious attackers. We discuss a simple estimation technique to calculate a relative clock drift rate between sender-receiver clocks, because the estimated relative clock drift rate …

Go to article

Towards Optimum Play-Out Buffering Delay In Voice Over Ip, Ruchir Pramod Shende May 2006

Towards Optimum Play-Out Buffering Delay In Voice Over Ip, Ruchir Pramod Shende

Computer Science and Engineering Theses - Archive

Voice over Internet Protocol (VoIP) or transmission of real-time voice packets over the Internet is slowly emerging as a cost-effective alternative to the traditional Public Switched Telephone Network (PSTN). However, varying end-to-end delay and packet loss, which are inherent in a packet-switched network like the Internet, lead to relatively lower quality of VoIP calls. The call quality can be improved by adaptively adjusting the play-out buffer at the receiver to reduce the impact of the delay and jitter. A standard play-out strategy uses a weighted moving average of the mean and variance of network delay to adaptively set the play-out …

Go to article

Air Jet Impingement For Levitation, James Frederick Huber May 2006

Air Jet Impingement For Levitation, James Frederick Huber

Mechanical and Aerospace Engineering Theses - Archive

Traditional part acquisition methods such as vacuum cups and robotic grippers do not meet the handling needs of truly fragile materials, because both of these methods require surface contact. An alternative to these traditional approaches is the use of air jet impingement for levitation. This technique confines impinged air to a thin disk above the target to form radial diffuser. The Bernoulli Effect causes a pressure difference between the fast-moving impinged air above the surface and ambient air below it. The net pressure difference is sufficient to lift objects weighing more than one kilogram using standard shop air. This method …

Go to article

Frequency Response Approximation Methods Of The Dissipative Model Of Fluid Transmission Lines, John King May 2006

Frequency Response Approximation Methods Of The Dissipative Model Of Fluid Transmission Lines, John King

Mechanical and Aerospace Engineering Theses - Archive

This thesis introduces an accurate and efficient method of obtaining a linear approximation for a nonlinear model of a complete fluid transmission line system using Matlab® Signal Processing Toolbox and Symbolic Math Toolbox programs. This technique is then packaged in a Graphical User Interface program to streamline the process of analyzing a total system. The method of approximating the frequency response of a fluid transmission line with a rational polynomial transfer function using the Matlab® 'invfreqs' least squares curve fitting algorithm has already been introduced. This research improves the technique by applying the 'invfreqs' command to a total system rather …

Go to article

Regional Prioritization Of Corridors For Traffic Signal Retiming, Sasanka Bhushan Pulipati May 2006

Regional Prioritization Of Corridors For Traffic Signal Retiming, Sasanka Bhushan Pulipati

Civil Engineering Theses - Archive

Every three to four years, the North Central Texas Council of Governments (NCTCOG) funds signal retiming projects to improve air quality in the Dallas-Fort Worth region. As sufficient funds are not available to retime all signals in the region at the same time, the retiming must be completed in phases. To optimize the impact of the retiming projects, the candidate corridors must be rank ordered or prioritized. NCTCOG applies a ranking model, which uses variables like delay, number of stops and system type, a dummy variable based on centralized control. The weighting for each factor is based on expert input …

Go to article

Mr Susceptibility Weighted Imaging And Its Clinical Applications, Nandita R. Shetty May 2006

Mr Susceptibility Weighted Imaging And Its Clinical Applications, Nandita R. Shetty

Bioengineering Theses - Archive

Susceptibility Weighted Imaging (SWI) is a new T2* weighted Gradient Echo sequence that exploits the magnetic properties of tissues due to local inhomogeneities in the magnetic field. This technique was originally called 'High-Resolution Blood oxygen level dependent Venography' which, as the name suggests provides an increased visibility of the venous vasculature in the brain, including the minute vessels not seen on conventional imaging techniques. Since its potential is not restricted to venography, it was renamed 'Susceptibility Weighted Imaging ' due to its contrast mechanism being the susceptibility differences between two tissues. The essential feature in this technique is to tap …

Go to article

Fpga Prototyping For Fast And Efficient Verification Of Asic H.264 Decoder, Basavaraj Mudigoudar May 2006

Fpga Prototyping For Fast And Efficient Verification Of Asic H.264 Decoder, Basavaraj Mudigoudar

Electrical Engineering Theses - Archive

To improve compression efficiency, recent video compression standards such as H.264 use complex algorithms and various modes that demand more computational power. Consumer electronics industry requires a low power, compact and cost-effective implementation of video codec for most of the products. ASIC implementation of these video codecs is a logical choice to meet these requirements. Functional verification of an ASIC implementation consumes a major part of design cycle time and lot of resources. Because of large design, various modes and options, functional verification of an ASIC H.264 video codec is a challenging, resource intensive and time consuming process. In this …

Go to article

Simulation And Characterization Of Znse/Bete Resonant Tunneling Diode On Silicon, Moshe Davis May 2006

Simulation And Characterization Of Znse/Bete Resonant Tunneling Diode On Silicon, Moshe Davis

Electrical Engineering Theses - Archive

ZnSe/BeTe resonant tunneling diodes were grown on silicon with a ZnxBe1-xTe buffer layer using MBE (Molecular Beam epitaxy).These devices were processed and characterized. The devices showed multiple NDR (negative differential resistance) regions at room temperature with PVR (Peak to valley ratios) between 1.01 to 1.23. Variations to the structure were made in growth and their corresponding current-voltage characteristics were studied. The ZnSe/BeTe resonant tunneling diode showed asymmetrical current voltage characteristics for positive and negative biases. The sources of asymmetry were investigated during fabrication and with the help of simulations. The Al/ZnSe contact was confirmed to be ohmic contact when the …

Go to article

Real-Time Data Monitoring And Manipulation For Wireless Sensor Networks, Sankar Bhanu Gorthi May 2006

Real-Time Data Monitoring And Manipulation For Wireless Sensor Networks, Sankar Bhanu Gorthi

Electrical Engineering Theses - Archive

The growth of Wireless Sensor Network research has brought about the need for tools to help developers rapidly develop applications for various platforms. In the pursuit of these capabilities, this work deals with the design of a graphical approach to development of Wireless Sensor Network applications for implementation in the LabVIEW Graphical Development Environment. The work done also covers the implementation and development of the Sound and Vibration Toolkit for LabVIEW. The implementation of these tools in developing a novel test-bed at the Distributed Intelligence and Automation Laboratory at the ARRI at UT Arlington is also shown. This work is …

Go to article

Structural Similarity Based Image Quality Assessment: Pooling Strategies And Applications To Image Compression And Digit Recognition, Xinli Shang May 2006

Structural Similarity Based Image Quality Assessment: Pooling Strategies And Applications To Image Compression And Digit Recognition, Xinli Shang

Electrical Engineering Theses - Archive

This thesis studies a recently proposed perceptual image similarity measure: the structural similarity (SSIM) index. Although still in its early stage, the SSIM index has demonstrated superior performance in a large number of tests as compared to the currently most widely used image distortion/quality measures, the mean squared error (MSE) and the peak signal-to-noise-ratio (PSNR). This motivates us to further investigate the SSIM method and extend it to other image processing and pattern recognition applications. Specifically, three topics have been studied in this thesis: spatial pooling strategies for perceptual image quality assessment, structural similarity-guided perceptual image compression, and handwritten digit …

Go to article

Design And Hardware Implementation Of A Soft-Switched Converter For Fuel Cell Applications, Shiju Wang May 2006

Design And Hardware Implementation Of A Soft-Switched Converter For Fuel Cell Applications, Shiju Wang

Electrical Engineering Theses - Archive

The focus of this thesis is to design a DC-DC quasi-soft switched boost converter suitable for fuel cell applications. Study of electrical output characteristics of fuel cells was necessary for this purpose. A number of experiments were conducted to study the steady-state and transient response of fuel cell system under various load dynamics. The results of these findings were necessary for the next phase of the project which was to design a reliable and high-performance regulated DC-DC converter. The design goals were realized with a soft-switching boost converter (implementation of zero voltage switching (ZVS) and zero current switching (ZCS) schemes) …

Go to article

Design Of An Enhanced Translinear Variable Floating Resistor And Its Application In A Vga, Nithya Jagannathan May 2006

Design Of An Enhanced Translinear Variable Floating Resistor And Its Application In A Vga, Nithya Jagannathan

Electrical Engineering Theses - Archive

An improved current controlled floating resistor is designed based on translinear loops for application in a Variable Gain Amplifier (VGA). This work compares the use of two different devices and evaluates the difference based on the model parameters and circuit performance. The different architectures employed clearly demarcate the performance variations. The translinear variable resistor exhibits a dynamic range greater than 60 mV. The resistance value lies in the range of 3 K? to few Ohms. A Current Feedback Operational Amplifier (CFOA) is also designed to have an f -3dB of 250 MHz. The CFOA together with the variable resistor in …

Go to article

Generalization Of Widely Linear Filtering Concepts For Equalization And Interference Suppression In Pam/Qam Systems, Kiran Kumar Kuchi May 2006

Generalization Of Widely Linear Filtering Concepts For Equalization And Interference Suppression In Pam/Qam Systems, Kiran Kumar Kuchi

Electrical Engineering Dissertations - Archive

In PAM/QAM transmission systems, standard Minimum Mean Square Error (MMSE) linear (LE) or Decision Feedback Equalization (DFE) equalization methods are often used to suppress the detrimental effects inter-symbol and/or co-channel interference (ISI/CCI) effects of the channel. In this thesis we show the benefits of a new signal processing concept called Widely Linear (WL) filtering for equalization applications in wireless systems. In particular, we introduce generalized WL MMSE/MMSE-DFE equalization structures for both PAM systems that use real constellations and QAM (that use complex modulation alphabets) with multiple antennas and multiple co-channel interferers. In this thesis we first show that WL equalizers …

Go to article

Design And Fabrication Of Optically-Pumped Guided-Mode Resonance Surface-Emitting Lasers, Preston Phillip Young May 2006

Design And Fabrication Of Optically-Pumped Guided-Mode Resonance Surface-Emitting Lasers, Preston Phillip Young

Electrical Engineering Dissertations - Archive

This dissertation describes the design and fabrication of guided-mode resonance (GMR) structures and their applications to laser devices. These include tunable Ti:Sapphire lasers as well as semiconductor lasers with integrated light emitting layers. The resonance characteristics of GMR structures are determined by the designed and fabricated waveguide-grating parameters. The primary tool for the design and simulation analysis of GMR devices is rigorous coupled-wave analysis (RCWA). This numerical method is used to provide diffraction efficiency calculations as well as simulations of the electric fields within GMR structures. RCWA-based field analysis is used to design an optically pumped GMR surface-emitting laser (GMR-SEL) …

Go to article

A Novel Approach In The Detection Of Obstructive Sleep Apnea From Electrocardiogram Signals Using Neural Network Classification Of Textural Features Extracted From Time-Frequency Plots, Mohammad Alabed May 2006

A Novel Approach In The Detection Of Obstructive Sleep Apnea From Electrocardiogram Signals Using Neural Network Classification Of Textural Features Extracted From Time-Frequency Plots, Mohammad Alabed

Bioengineering Theses - Archive

Sleep-Disordered Breathing (SDB) is estimated to have a prevalence of 5% in middle-aged population. The population is widely thought to be under diagnosed, since the present method to detect and diagnose SDB, Nocturnal Polysomnography (NPSG), is still expensive and not accessible by most. SDB has been shown to affect the productivity and degree of life of the patient, and to have a high correlation with obesity and cognitive heart failure (CHF). Cheap and accessible means to screen the population for SDB are greatly pursued. This work presents an automatic algorithm to detect obstructive sleep apnea (OSA) events in 15-minute clips. …

Go to article

Influence Of Polymer Surface Chemistry On The Recruitment Of Stem Cells In Mice, Shwetha Kamath May 2006

Influence Of Polymer Surface Chemistry On The Recruitment Of Stem Cells In Mice, Shwetha Kamath

Bioengineering Theses - Archive

The most troublesome biological response to the implantation of bloodcontacting biomaterials is inflammation, which thereby-sets in motion a cascade of adverse host responses. If devices for therapy and drug delivery could be developed that prevent such responses from occurring altogether, a new generation of "stealth" biomaterials would be born. Such was the motivation of this project, which sought to investigate using mouse subcutaneous implantation model, the implant mediated host tissue responses to surfaces differing in their functionalities. During the course of a previous study in our laboratory, we accidentally discovered the presence of stem cells and their accumulation at the …

Go to article

Characterization Of A Noninvasive, In Vivo, Microscopic Hyperspectral Imaging System For Microvascular Visualization., Bhavesh Shah May 2006

Characterization Of A Noninvasive, In Vivo, Microscopic Hyperspectral Imaging System For Microvascular Visualization., Bhavesh Shah

Bioengineering Theses - Archive

Instrumentation with clinical implications for imaging the human oculus was developed, based upon the hyperspectral imaging modality. The novel, non invasive, microscopic multi-modal hyperspectral imaging system, which operates in the visible as well as near infrared region, is capable of generating images illustrating spatial distribution of oxyhemoglobin contributions. The device principally comprises of a liquid crystal tunable filter and a focal plane array detector that is integrated to the slit lamp microscope. A proof of principle clinical study involving ten healthy subjects was undertaken to image the microvascular structure within the dermal tissue within the near infrared region, however these …

Go to article

Design And Construction Of A Fast Spectrometer For Fourier Domain Optical Coherence Tomography, Manish Kankaria May 2006

Design And Construction Of A Fast Spectrometer For Fourier Domain Optical Coherence Tomography, Manish Kankaria

Bioengineering Theses - Archive

A fast spectrometer capable of operating at 27.8 KHz is designed and calibrated to work in the wavelength range of 700-900 nm, to perform Fourier Domain Optical Coherence Tomography (FD-OCT). The OCT system is based on fiber-based Michelson's interferometer set up utilizing the spectrometer at the detector end. In FD-OCT system no reference scanning is necessary and hence images can be acquired at a much faster rate without any penalty to signal-to-noise ratio (SNR). A broadband Ti- sapphire source is used as input to this interferometer. Data at the rate of 60 MHz is acquired from the spectrometer using a …

Go to article

Structural Optimization Using Femlab And Smooth Support Vector Regression, Divija Odapally May 2006

Structural Optimization Using Femlab And Smooth Support Vector Regression, Divija Odapally

Mechanical and Aerospace Engineering Theses - Archive

In recent years support vector machine (SVM) has been emerging as a popular tool for function approximation. Application of SVM for approximation of mathematical functions and complex engineering analysis has been represented by Palancz et al and Clarke et al, respectively. However the training of the original SVM involves the solution of a quadratic programming (QP) problem. This makes the application of SVM to large problem computationally expensive. To circumvent this difficulty, Lee et al developed a more efficient SVM formulation namely epsilon-SSVR which drastically improved the training efficiency of SVM. In this research the SSVR is used to build …

Go to article

Concept-Based Search Using Parallel Query Expansion, Rahul Rajiv Joshi May 2006

Concept-Based Search Using Parallel Query Expansion, Rahul Rajiv Joshi

Computer Science and Engineering Theses - Archive

We address the problem of irrelevant results for short queries on Web search engines. Short queries fail to provide sufficient context to disambiguate possible meanings associated with the search terms resulting in a set of irrelevant pages that the user has to filter through navigation and sometimes examination. First, we predict the potential concept topics, which are the domains for the search terms. This prediction is based on word occurrences and relationships observed in the various domains (categories) of a corpus. Next, we expand the search terms in each of the predicted domains in parallel. We then submit separate queries, …

Go to article

Ubca: A Utility Based Clustering Architecture For Peer-To-Peer Networks, Brent Lagesse May 2006

Ubca: A Utility Based Clustering Architecture For Peer-To-Peer Networks, Brent Lagesse

Computer Science and Engineering Theses - Archive

Use of the Peer-to-Peer (P2P) architecture has recently spread in popularity. File sharing and ad hoc networks have contributed to the architecture's usage. P2P generates new challenges in scalability, fairness, and quality of service. Current solutions tend to fall into two main areas: incentives and system design. Incentive-based approaches appeal to the self-interested nature of peers by requiring service to the system in order to access resources. System design includes distributed hash tables and graph-theoretical based designs which have seen some success, but also result in new problems. We introduce a Utility-Based Clustering Architecture, UBCA, designed to address scalability, fairness, …

Go to article

First Prev Next Last