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 7561 - 7590 of 8682

Full-Text Articles in Entire DC Network

Enhanced Bioinformatics Data Modeling Concepts And Their Use In Querying And Integration, Feng Ji Aug 2008

Enhanced Bioinformatics Data Modeling Concepts And Their Use In Querying And Integration, Feng Ji

Computer Science and Engineering Dissertations - Archive

In bioinformatics research, scientists usually face the problems of modeling complex data types and integrating diverse resources. Traditional data models such as EER lack the expressing power to capture many characteristics that are common in bioinformatics data. We first propose extensions to the ER model that allow accurate representation of many of these characteristics. We then utilize these concepts in an integrative system to provide an easy-to-use interface for biologists to construct queries. Our research utilizes the enhanced conceptual modeling concepts to create a prototype mediator for querying multiple data sources. The various relationships between different biological entities are all …

Go to article

Automation Of Thermal Model Extraction And Optimization, Obiorah Oji Aug 2008

Automation Of Thermal Model Extraction And Optimization, Obiorah Oji

Electrical Engineering Theses - Archive

Semiconductor device model optimization is highly beneficial; it improves the accuracy with which we can predict the performance of real devices and whole circuits before they are fabricated. This helps save time and money in being able to predict undesirable circuit responses. Although, it proves to be very useful, it can become very time consuming. The goal of this thesis is to use readily available tools to enhance and automate the somewhat complex process of optimization and streamline it so that results can be analyzed quicker with the goal of generating VBIC models that accurately match the behavior of the …

Go to article

Exploratory Study Of Gold Nanoshell As A Therapeutic Thermal Ablation Agent For Cancer Treatment Using Laboratory And Animal Tissue Phantoms, Yajuvendra Rathore Aug 2008

Exploratory Study Of Gold Nanoshell As A Therapeutic Thermal Ablation Agent For Cancer Treatment Using Laboratory And Animal Tissue Phantoms, Yajuvendra Rathore

Bioengineering Theses - Archive

Prostate cancer is the most common male cancer in the United States and the second leading cause of male death from cancer. Surgical removal of the prostate is associated with high risks of surgical complications and consequences such as incontinence and sexual dysfunction. In my study, I have investigated a nanoparticle-assisted photothermal therapeutic method that may be used for treatment of prostate cancer in the future. This method is minimally-invasive and uses gold nano-shells as hyperthermia agents to treat localized necrosis of cancer cells. I have conducted a feasibility study for a new class of NIR absorbing nanoparticles called Gold …

Go to article

Study Of Normobaric Hyperoxia Effects During Focal Hypoxia-Ischemic Injury In Mice Using Optical Spectroscopy Measurements, Shereen Mohideen Aug 2008

Study Of Normobaric Hyperoxia Effects During Focal Hypoxia-Ischemic Injury In Mice Using Optical Spectroscopy Measurements, Shereen Mohideen

Bioengineering Theses - Archive

Optical spectroscopy has seen tremendous growth and development in recent years and has been extensively used to characterize the optical properties of biological tissues. The purpose of this study is to investigate the values of oxygen saturation and concentration of hemoglobin in mice with focal hypoxic ischemia after being recovered in normobaric hyperoxia. Mice at five different age levels were used for this purpose, in order to see the effects of hyperoxia at different developmental stages of the brain; ischemia was induced in them by ligating their right carotid artery and subjecting them to hypoxic (8% oxygen) environment for half …

Go to article

Model Driven Analysis Of Optical Reflectance Spectroscopy For Detection Of Human Prostate And Kidney Cancers, Aditya Vivek Mathker Aug 2008

Model Driven Analysis Of Optical Reflectance Spectroscopy For Detection Of Human Prostate And Kidney Cancers, Aditya Vivek Mathker

Bioengineering Theses - Archive

Renal cell carcinoma is one of the most common forms of kidney cancer originating from the renal tubule. During surgery, it is difficult for the surgeons to identify the cancer tissue from the normal tissue and also the benign tumor from malignant tumor. Moreover, prostate cancer is the leading cause of death amongst men in the United States. In this study, optical reflectance spectroscopy with short source-detector separation is used as a minimally invasive technique to differentiate normal tissues from tumor lesions and also to differentiate benign from malignant tissues in renal cell carcinoma. Clinical post-operative readings were obtained using …

Go to article

Comparison Of Hemodynamic Response Non-Linearity Using Simultaneous Functional Near Infrared Spectrsoscopy And Magnetic Resonance Imaging Modalities, Renuka Parlapalli Aug 2008

Comparison Of Hemodynamic Response Non-Linearity Using Simultaneous Functional Near Infrared Spectrsoscopy And Magnetic Resonance Imaging Modalities, Renuka Parlapalli

Bioengineering Theses - Archive

Blood oxygenation level dependent (BOLD) response, which is measured by functional magnetic resonance imaging (fMRI), is known to be a combination of various vascular parameters, among which deoxy-hemoglobin is argued to be a major contributor. Functional near infrared spectroscopy (fNIRS) though limited in its spatial resolution provides a promising tool to study cortical activations, due to its specificity of independent measurement of blood parameters (Oxy, De-oxy and Total Hemoglobin), high temporal resolution and ease of use. To integrate the best aspects of two imaging modalities, it becomes important to study the close relationship between the two imaging modalities. A finger …

Go to article

Surgical Fluorescence Imager For Visualizing Anteriorly Placed Biliary Structures, In-Vivo During Human Cholecystectomy, Santosh Hariharan Aug 2008

Surgical Fluorescence Imager For Visualizing Anteriorly Placed Biliary Structures, In-Vivo During Human Cholecystectomy, Santosh Hariharan

Bioengineering Theses - Archive

Cholecystectomy is one of the most common procedures occurring in United States to cure gall bladder diseases. There are two means of performing this procedure, Open Cholecystectomy and Laparoscopic Cholecystectomy, the later one being more frequent. The critical issue while performing Cholecystectomy is injury to Common Bile Duct (CBD) which could cause post procedural complications. Since the CBD is under fat layer it is important to image and locate the CBD during the procedure. The novel fluorescence imager developed in this project would help visualize the CBD by using the fluorescence properties of Indocyanine Green, to be injected into the …

Go to article

Study Of Nirs Based Motor Cortex Activation Patterns In Cerebral Palsy Affected Kids Using Image Based Metrics, Nayan Jaikrishna Asanani Aug 2008

Study Of Nirs Based Motor Cortex Activation Patterns In Cerebral Palsy Affected Kids Using Image Based Metrics, Nayan Jaikrishna Asanani

Bioengineering Theses - Archive

In recent years the National Institutes of Health has placed great emphasis on addressing the emergent need to accelerate translation of laboratory discoveries into clinical practice. The proposed study is very much aligned with this NIH emphasis, targeting on the translation of near infrared (NIR) brain imaging to clinical assessment for children with cerebral palsy. Over ten million Americans are affected by central nervous system disorders that result in motor deficits. Cerebral palsy (CP) is the most common motor disorder of central origin in childhood and affects at least 2 children per 1000 live births every year . One of …

Go to article

Analysis And Design Of A Hypersonic Scramjet Engine With A Starting Mach Number Of 4.00, Kristen Nicole Roberts Aug 2008

Analysis And Design Of A Hypersonic Scramjet Engine With A Starting Mach Number Of 4.00, Kristen Nicole Roberts

Mechanical and Aerospace Engineering Theses - Archive

When pressures and temperatures become so high in supersonic flight that it is no longer efficient to slow the oncoming flow to subsonic speeds for combustion, a scramjet (supersonic combustion ramjet) is used in place of a ramjet. Currently, the transition to supersonic combustion generally occurs at a freestream Mach number around 5.0 to 6.0. This research details analysis completed towards extending scramjet operability to lower Mach numbers, while maintaining performance at higher Mach numbers within the same flowpath as detailed in the Air Force solicitation AF073-058. The specific goal is to determine whether the scramjet starting Mach number can …

Go to article

Subsurface Investigations Using High Resolution Resistivity, Dharmateja Maganti Aug 2008

Subsurface Investigations Using High Resolution Resistivity, Dharmateja Maganti

Civil Engineering Theses - Archive

Electrical resistivity imaging has been proved to be well suited to produce images of subsurface conditionsbecause of the ability of the technique for detecting resistive features and discriminating subtle resistivity variations in the soil media. Electrical resistivity imaging survey was performed at E. Center Development in Duncanville, Texas. The survey was conducted using SuperSting R8/IP Multi-channel Resistivity Imaging System to image the subsurface structure. Both 2-D and 3-D electrical resistivity imaging tests were conducted using dipole-dipole array at 2 feet, 5 feet and 20 feet electrode spacing. Earth Imager 2D and Earth Imager 3D software's were then used to invert …

Go to article

Sealing And Lamination Of Microfluidic Devices, Christopher Ryan Oliver Aug 2008

Sealing And Lamination Of Microfluidic Devices, Christopher Ryan Oliver

Industrial, Manufacturing, and Systems Theses - Archive

A difficult problem facing microfluidic manufacturing of devices remains that often material requirements force device designers to choose materials that are difficult to bond, seal or enclose. Examples of these materials include the Polyolefin family such as HDPE (High Density Polyethylene), PP (Polypropylene) or high performance polymers such as PEEK (Polyetheretherketone), Acetal or Polyimide. The problem arises from the chemical resistance of the materials making them ideal for processing corrosive chemicals but the same property reduces the effectiveness of laminates, surface bonding, surface coatings and solvents. To address this problem a methodology for sealing devices made of these materials is …

Go to article

Material Flow Control In A Sequence Dependent Job Shop Via Order Release And Dispatching Mechanisms, Francesco Gentile Aug 2008

Material Flow Control In A Sequence Dependent Job Shop Via Order Release And Dispatching Mechanisms, Francesco Gentile

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Material flow control on the shop floor involves the release and dispatching of orders to meet customer due dates, while minimizing operating costs. The early release of orders to the shop floor does not necessarily ensure delivery performance and often results in unnecessary shop congestion and excessive cost. Thus, determining when order release should occur and how dispatching should be accomplished is critical to the success of a manufacturing organization. Although there has been a significant amount of research in the material flow control literature regarding the job shop environment, there exists a significant void with respect to order release …

Go to article

Design Of A Signal Generator Using Current Feedback Operational Amplifiers, Akm Sydul Haque Aug 2008

Design Of A Signal Generator Using Current Feedback Operational Amplifiers, Akm Sydul Haque

Electrical Engineering Dissertations - Archive

Sinusoidal, triangular and rectangular waveforms are generated using current feedback operational amplifiers. A signal generator using a Current Feedback Operational Amplifier (CFOA) was designed, simulated and fabricated. The simulated frequency of oscillation for the sinusoidal wave is 13.13 MHz to 23.94 MHz, for the triangular and the rectangular wave are 6.78 MHz to 59.5 MHz in simulation. The current feedback operational amplifier can achieve higher oscillation frequency than a voltage feedback operational amplifier. Two different types of current feedback operational amplifiers were designed. These are the double buffer current feedback operational amplifier and the double buffer current booster current feedback …

Go to article

Location Privacy In Sensor Networks Against A Global Eavesdropper, Kiran K. Mehta Aug 2008

Location Privacy In Sensor Networks Against A Global Eavesdropper, Kiran K. Mehta

Computer Science and Engineering Theses - Archive

While many protocols for sensor network security provide con dentiality for the content of messages, contextual information usually remains exposed. Such contextual information can be exploited by an adversary to derive sensitive information such as the locations of monitored objects and data sinks in the eld. Attacks on these components can signi cantly undermine network applications. The existing techniques defend the leakage of location information only from an adversary who sees only local network tra c. However, a stronger adversary, the global eavesdrop- per, is realistic and can defeat all existing techniques. This paper rst formalizes the location privacy issues …

Go to article

Sequential Frameworks For Statistics-Based Value Function Representation In Approximate Dynamic Programming, Huiyuan Fan Aug 2008

Sequential Frameworks For Statistics-Based Value Function Representation In Approximate Dynamic Programming, Huiyuan Fan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Dynamic programming (DP) was derived by Bellman in 1957 as a mathematical programming method to solve multistage decision problems. The DP concept has great potential, but it only can solve small problems exactly under very limiting restrictions such as linear dynamics, quadratic cost, Gaussian random variable, etc. With advances in computational power, a new family of dynamic programming known as approximate dynamic programming (ADP) has emerged. A real-world DP problem is often high-dimensional and stochastic with continuous state variables. To handle this type of problem, ADP methods discretize/sample the continuous state space and approximate the future value (or cost-to-go) function …

Go to article

Automated Integration Of Biomedical Information For The Support Of Genome-Wide Association Studies, Abhijit R. Tendulkar Aug 2008

Automated Integration Of Biomedical Information For The Support Of Genome-Wide Association Studies, Abhijit R. Tendulkar

Computer Science and Engineering Theses - Archive

Genome-wide association studies of the genetic underpinnings of complex phenotypes, and human diseases in particular, have been steadily gaining momentum over the past several years. Yet, the number of polymorphic sites in the human genome, including, but not limited to, Single Nucleotide Polymorphisms (SNPs) is so large that identifying the combination of these few which have a significant effect on the condition of interest remains an overwhelming task. The goal of this thesis work was to identify biologically and medically relevant SNPs which could be the best possible candidates for further association studies. In this thesis we present a new …

Go to article

Congestion Control For Networks In Challenged Environments, Guohua Zhang Aug 2008

Congestion Control For Networks In Challenged Environments, Guohua Zhang

Computer Science and Engineering Dissertations - Archive

Congestion occurs when resource demands exceed the capacity of a network. The goal of congestion control is to use the network as efficiently as possible. While extensive efforts have been devoted to providing optimization based, distributed congestion control schemes for efficient bandwidth utilization and fair allocation in the Internet and wireless networks, little consideration was given to congestion control for networks in challenged environments, specifically for networks with time-varying link capacities and networks that intermittently communicate. In this dissertation, we explore optimal congestion control strategies for such networks based on optimization techniques and repeated game theory. For networks with time …

Go to article

High Performance Cluster And Grid Computing Solutions For Science, Umeshkumar Ashok Keswani Aug 2008

High Performance Cluster And Grid Computing Solutions For Science, Umeshkumar Ashok Keswani

Computer Science and Engineering Theses - Archive

Computing for science has very peculiar requirements. There is an enormous amount of data to analyze to get useful information. This requires greater computing power, huge data storage and high-capacity network. High Performance Computing (HPC) is the perfect solution that satisfies these requirements. Here, we look at two high performance implementations that provide useful solutions to computing problems in science, making possible scientific experiments and discoveries that otherwise would not have been possible.

Go to article

Computational Analysis Of Variability Of Recombination In Mice, Vishnukumar Galigekere Nagabhushana Aug 2008

Computational Analysis Of Variability Of Recombination In Mice, Vishnukumar Galigekere Nagabhushana

Computer Science and Engineering Theses - Archive

Rapid advances in engineering and technology have fueled research in areas such as molecular biology and genetics to a new level and thus have given birth to multidisciplinary fields like bioinformatics and computational biology. These fields involve the application of one's expertise in one or more areas including computer science, information science, statistics, chemistry and mathematics to solve problems related to biology in general and molecular biology and genetics in particular. It is a challenging research area which requires one to grasp diverse fields at almost equal rigor and at the same time provides new insights into the fascinating field …

Go to article

The Dynamics Of Salsa: A Structured Approach To Large-Scale Anonymity, Safwan Mahmud Khan Aug 2008

The Dynamics Of Salsa: A Structured Approach To Large-Scale Anonymity, Safwan Mahmud Khan

Computer Science and Engineering Theses - Archive

Anonymity provides a technical solution for protecting one's online privacy. Highly distributed peer-to-peer (P2P) anonymous systems should have better distribution of trust and more scalability than centralized approaches, but existing systems are vulnerable to attacks as they require nodes to have global knowledge of the system. To overcome these problems and to provide more secure, distributed organization for P2P anonymity systems, prior work proposed the Salsa system. Salsa is designed to select nodes to be used in anonymous circuits randomly from the full set of nodes, even though each node has knowledge of only a small subset of the network. …

Go to article

Mutual Information Based Non-Rigid Image Registration Using Adaptive Grid Generation: Gpu Implementation And Application To Breast Mri, Mei Yi Chu Aug 2008

Mutual Information Based Non-Rigid Image Registration Using Adaptive Grid Generation: Gpu Implementation And Application To Breast Mri, Mei Yi Chu

Computer Science and Engineering Dissertations - Archive

In this dissertation a new approach for non-rigid image registration using mutual information is introduced. A fast method for non-rigid registration is developed by adjusting divergence and curl of an intermediate vector field from which the deformation field is computed using finite difference method. The similarity measure mutual information is employed in the gradient-based cost minimization (or mutual information maximization) of the registration. The huge amount of data associated with MRI is handled by fully automated algorithm optimized with a multi-resolution topology preserving regridding scheme. The adaptive grid system naturally distributes more grids to deprived areas. The positive monitor function …

Go to article

Life Cycle Assessment Of Bio-Material Stabilized Expansive Soils, Ranjith Samuel Rosenberk Aug 2008

Life Cycle Assessment Of Bio-Material Stabilized Expansive Soils, Ranjith Samuel Rosenberk

Civil Engineering Dissertations - Archive

Pavement cracking is one of the major maintenance works that requires millions of dollars in repair costs annually. Pavement cracks are formed due to moisture and temperature fluctuations in the soil. Stabilization of pavement shoulder subsoil with the addition of compost material was studied for preventing pavement cracks. Eight different compost materials with three major feed stock sources such as biosolids, wood waste, and animal manure were investigated in this research. Compost treatment studies were performed at four different test sites located in various regions of the state of Texas. Laboratory experiments were conducted completed compost manufactured topsoil's (CMTs) to …

Go to article

Effects Of Calcium-Based Treatment On Organic Soil Behavior, Srujan Rao Chikyala Aug 2008

Effects Of Calcium-Based Treatment On Organic Soil Behavior, Srujan Rao Chikyala

Civil Engineering Theses - Archive

Organic soils are found in many places around the world. Organic soils undergo large secondary settlements depending on the amount of organic matter present in the soil Organic soil is a mixture of finely divided particles of organic matter, in some instances visible fragments of partly decayed vegetable matter and shells are also present in the organic matter. In order to reduce the secondary settlements caused by organic matter, soil is treated with different stabilizing agents. The difficulties associated with organic soils arise when they are treated with cement or lime stabilizers, as organic matter inhibits cementitious reactions responsible for …

Go to article

Influence Of Hypoxia, Hypercapnia And Inspiratory Efforts On Sympathoexcitation During Apnea, Vikram Rao Aug 2008

Influence Of Hypoxia, Hypercapnia And Inspiratory Efforts On Sympathoexcitation During Apnea, Vikram Rao

Bioengineering Theses - Archive

Obstructive Sleep Apnea (OSA) is characterized by frequent periods of apnea resulting in hypoxia, hypercapnia and fluctuations of intrathoracic pressure (inspiratory efforts). Hypoxia, hypercapnia and inspiratory efforts lead to stimulation of peripheral chemoreceptors, central chemoreceptors and baroreceptors, respectively, which in turn influence Muscle Sympathetic Nerve Activity (MSNA). We hypothesized that hypoxia and hypercapnia result in an elevated MSNA response, while inspiratory efforts result in a reduced MSNA response during apnea. To test the hypothesis, we determined the contributions of hypoxia (at 12% O2), hypercapnia (at 3% CO2) and inspiratory efforts (mueller maneuvers at 20 mmHg) to MSNA (using microneurographic techniques) …

Go to article

A Novel Approach For Mri Image Classification And Image Retrieval, Ankit Vinod Master Aug 2008

A Novel Approach For Mri Image Classification And Image Retrieval, Ankit Vinod Master

Bioengineering Theses - Archive

OBJECTIVE: Classification of MRI image data based on its attribute characteristics is very important for storing the image data and its efficient retrieval. This project aims to find a solution to the problem of classification of the images that are stored on a hard drive and image retrieval from the image database with optimum automation in a user friendly way. METHOD: Matlab was used to create a software tool for image classification and, Java and SQL were used to create a software tool for image retrieval. RESULTS: Image classification tool could read multiple files, extract attribute values from the files …

Go to article

Comparison Of Cooling Performance Of Overhead And Underfloor Supply With Rear Door Heat Exchanger In High Density Data Center Clusters, Ravi K. Udakeri Jul 2008

Comparison Of Cooling Performance Of Overhead And Underfloor Supply With Rear Door Heat Exchanger In High Density Data Center Clusters, Ravi K. Udakeri

Mechanical and Aerospace Engineering Theses - Archive

The power trend for server systems continues to grow thereby making thermal management of Data centers a very challenging task. Although various configurations exist, the raised floor plenum with Computer Room Air Conditioners (CRACs) providing cold air is a popular operating strategy. In prior work, numerous data center layouts employing raised floor plenum and the impact of design parameters such as plenum depth, ceiling height, cold isle location, tile openings and others on thermal performance of data center was presented. The air cooling of data center however, may not address the situation where more energy is expended in cooling infrastructure …

Go to article

Thermo-Mechanical Solutions In Electronic Packaging: Component To System Level, Aalok Trivedi Jul 2008

Thermo-Mechanical Solutions In Electronic Packaging: Component To System Level, Aalok Trivedi

Mechanical and Aerospace Engineering Theses - Archive

Since the advent of the transistor and integrated circuit, the performance of electronic equipment has increased significantly while footprint of systems at all levels continues to decrease. Recently, the number of transistors on a high end microprocessor has exceeded a billion. All of the above has necessitated considerable improvement in cooling technology and associated reliability. In this era of high heat fluxes, air cooling still remains the primary cooling solution mainly due to its cost and ease of installation and operation. The primary goal of a good thermal design is to ensure that the chip can function at its rated …

Go to article

Structural Optimization Using Matlab Partial Differential Equation Toolbox And Radial Basis Function Based Response Surface Model, Faisal Tanveer Mosharrof Jul 2008

Structural Optimization Using Matlab Partial Differential Equation Toolbox And Radial Basis Function Based Response Surface Model, Faisal Tanveer Mosharrof

Mechanical and Aerospace Engineering Theses - Archive

As a decision making tool, optimization has become an inseparable part of the modern design process. However, in spite of the advances in computer capacity and speed, the computational time for some complex problems is too high to use conventional solution approach. In order to reduce the computational effort and the cost associated with such type of problems, approximation methods such as response surface methodology (RSM) along with design of experiments (DOE) are used in engineering design optimization. The main idea involves replacing the expensive simulation model during the design and optimization process with a simplified mathematical approximation of the …

Go to article

Design Of Analog Correlator For 22-29ghz Uwb Vehicular Radar Systems In Ibm 90nm Cmos Process, Niranjan Karandikar Jul 2008

Design Of Analog Correlator For 22-29ghz Uwb Vehicular Radar Systems In Ibm 90nm Cmos Process, Niranjan Karandikar

Electrical Engineering Theses - Archive

In this thesis analog correlator is designed for UWB vehicular radar system. Operating frequency of the correlator is 22-29GHz. IBM 90nm CMOS process is used for the design, Simulation are done in CADENCE Spectre and SpectreRF. UWB signal of 22-29GHz is generated in ADS. Gaussian mono-pulse is shaped with band-pass filter to meet FCC mask. Simulations are done by using this signal. Typical receiver of UWB system consists of LNA, analog correlator and ADC. Analog correlator is the matched filter which is a part of receiver. It is used to detect the incoming RF signal by maximizing signal to noise …

Go to article

Simulation Of Tetrahedral Mesh Based Organ Deformation Using Parameter Optimized Spring Constants, Koyel Mukherjee Jul 2008

Simulation Of Tetrahedral Mesh Based Organ Deformation Using Parameter Optimized Spring Constants, Koyel Mukherjee

Electrical Engineering Theses - Archive

Virtual reality based surgical simulators are becoming increasingly popular for training doctors on minimally invasive surgery. For these simulators, it is necessary to generate 3D organ models and create virtual environments depicting visually realistic deformation response by tissues and organs to manipulations by surgical tools. For creating a 3D model, several different approaches have been used by the computer graphics community, among which polygonal/polyhedral meshes have gained popularity for real time virtual reality applications. This work investigates two problems in 3D organ modeling for virtual reality simulators. Firstly, we consider the use of unstructured 3D meshes for generation of organ …

Go to article

First Prev Next Last