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2007

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Articles 2491 - 2520 of 3831

Full-Text Articles in Engineering

Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi Jan 2007

Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi

Master's Theses - Daytona Beach

The problem of formation control of multiple spacecraft using the virtual structure approach is studied. The thesis first summarizes the progress made in the area of spacecraft formation control and then provides an overview of the virtual structure method. Modifying earlier established control design techniques, new feedback laws are constructed to control both the rotational and translational motion of a group of spacecraft. Several computer simulations are performed to illustrate the effectiveness of the modified control laws. The ephemeris and attitude data files generated via Matlab are exported to Satellite Tool Kit (STK) to create 3D animations. Various formation scenarios …

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Resistance Of The Target Islet Tissue To Autoimmune Destruction Contributes To Genetic Susceptibility In Type 1 Diabetes., Natasha J. Hill, Aleksandr Stotland, Michelle Solomon, Patrick Secrest, Elizabeth Getzoff, Nora Sarvetnick Jan 2007

Resistance Of The Target Islet Tissue To Autoimmune Destruction Contributes To Genetic Susceptibility In Type 1 Diabetes., Natasha J. Hill, Aleksandr Stotland, Michelle Solomon, Patrick Secrest, Elizabeth Getzoff, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Type 1 diabetes occurs when self-reactive T lymphocytes destroy the insulin-producing islet beta cells of the pancreas. The defects causing this disease have often been assumed to occur exclusively in the immune system. We present evidence that genetic variation at the Idd9 diabetes susceptibility locus determines the resilience of the targets of autoimmunity, the islets, to destruction. Susceptible islets exhibit hyper-responsiveness to inflammatory cytokines resulting in enhanced cell death and increased expression of the death receptor Fas. Fas upregulation in beta cells is mediated by TNFR2, and colocalization of TNFR2 with the adaptor TRAF2 in NOD beta cells is altered. …

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Personal Information Management. A Framework For Development Of Personalisable Web Based Services, Christopher Fuchs Jan 2007

Personal Information Management. A Framework For Development Of Personalisable Web Based Services, Christopher Fuchs

Theses

The thesis research proposed herein will model, analyse and implement strategies for the development of personalised services. The goal of the research work is to design and implement a framework which supports developers by minimising the effort required in implementing personalised services. This includes the ability to react to localisation changes and to present proper information. An overall design goal is the independency of most components from each other which will be attained through the use of standard technologies and protocols and the consistent use of a component model. The result will include the proposed framework and the analyses of …

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Educating Engineers For The 21st. Century: And Why Some Elements Of History And Philosophy Should Be Incorporated Into The Curriculum, William Grimson, Mike Murphy, Eugene Coyle Jan 2007

Educating Engineers For The 21st. Century: And Why Some Elements Of History And Philosophy Should Be Incorporated Into The Curriculum, William Grimson, Mike Murphy, Eugene Coyle

Conference papers

It has been said that in some respects the Russian composer Igor Stravinsky was a magpie – borrowing styles and ideas from diverse sources for whatever musical project he was working on. The practice of engineering has this same characteristic in that it willingly takes ideas, knowledge and techniques from wherever in pursuit of completing its goal. Further, Engineering is, at least in part, in agreement with Fyodor Dostoevsky – ‘if everything on Earth were rational, nothing would happen’. Against such a background it is proposed that a framework based on both philosophy and the history of engineering, science and …

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Growing Research In A Traditionally Teaching-Oriented College, Mike Murphy, Michael Dyrenfurth Jan 2007

Growing Research In A Traditionally Teaching-Oriented College, Mike Murphy, Michael Dyrenfurth

Conference papers

There is increasing pressure on universities to contribute to ‘the knowledge society’ by increasing the level of research activity and output within the university. This is particularly true in the sciences, engineering and technology. This increased pressure applies equally to traditionally teaching-oriented colleges (TTOC), although not at the same scale as research-intensive universities. For the TTOC, given the primacy of teaching, this paper discusses the nexus between teaching and research and the question ‘why do research?’ is addressed within the overarching goal of embedding a research culture within the college. Initiatives to develop and grow sustainable research activity in traditionally …

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The Role Of Spontaneous Polarization And The Thickness Of Alignment Layers On The V-Shaped Switching In Flc Cells, V. Manjuladevi, J.K. Vij, Yuri Panarin Jan 2007

The Role Of Spontaneous Polarization And The Thickness Of Alignment Layers On The V-Shaped Switching In Flc Cells, V. Manjuladevi, J.K. Vij, Yuri Panarin

Articles

Ferroelectric liquid crystal mixtures with the various values of spontaneous polarizations were prepared, and the substrates were coated with different thicknesses of aligning agent. The frequency dependence of the electrooptic response of these materials in cells with various thickness of alignment layers has been measured. The coercive voltage as well as the contrast ratios are calculated. Our results support the ‘‘electrostatic model’’, according to which both the value of spontaneous polarization and the thickness of the alignment layer play important roles in the V-shaped switching.

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Comparative Evaluation Of Two Models Of Upqc For Suitable Interface To Enhance Power Quality, Malabika Basu, S. P. Das, Gopal Dubey Jan 2007

Comparative Evaluation Of Two Models Of Upqc For Suitable Interface To Enhance Power Quality, Malabika Basu, S. P. Das, Gopal Dubey

Articles

Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear loads, which require quality input supply. Also, load current harmonic isolation needs to be ensured for maintaining the quality of the supply current. The present paper describes two control scheme models …

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Enzymatic Synthesis And Characterization Of Oligopeptides, Co-Oligopeptides And Hydroxy Acid Capped Polypeptides In Mixed Aqueous Organic Media, Santhana Srinivasan Jan 2007

Enzymatic Synthesis And Characterization Of Oligopeptides, Co-Oligopeptides And Hydroxy Acid Capped Polypeptides In Mixed Aqueous Organic Media, Santhana Srinivasan

Doctoral Dissertations

"Proteolytic enzymes have been used for the synthesis of homo-oligomers and hydroxy acid capped peptides with amino acids and hydroxy acid esters as substrates in aqueous and aqueous organic biphasic and triphasic systems. However, successful incorporation of hydroxy acids in oligopeptide substrates has not been demonstrated. Use of monophasic media comprising of acetonitrile/water in which oligopeptide substrates were soluble was examined for the synthesis of oligomers of neutral and polar amino acids like Met, Tyr, Lys, Gly, Asp and Glu and tailored co-oligomers of Lys-Met and Arg-Met. Effect of reaction parameters such as starting substrate concentration, system composition, reaction time, …

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Modeling,Design,And Characterization Of Monolithic Bi-Directional Power Semiconductor Switch, Yue Fu Jan 2007

Modeling,Design,And Characterization Of Monolithic Bi-Directional Power Semiconductor Switch, Yue Fu

Electronic Theses and Dissertations

Bidirectional power switching devices are needed in many power management applications, particularly in lithium-ion battery protection circuitry. A monolithic bidirectional power switch fabricated with a simplified CMOS technology is introduced in this dissertation. Throughout the design process, ISE TCAD tool plays an important role. Design variables are carefully analyzed to improve the device performance or yield the best trade off. Optimization is done with the help of TCAD simulation and theoretical calculations. The device has been successfully fabricated using simplified 0.5 micron CMOS process. The experimental result shows a breakdown voltage of 25V. Due to the interdigitated source to source …

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Investigation Of Reactively Sputtered Silicon Carbon Boron Nitride (Sicbn) Thin Films For High Temperature Applications, Arun Vijayakumar Jan 2007

Investigation Of Reactively Sputtered Silicon Carbon Boron Nitride (Sicbn) Thin Films For High Temperature Applications, Arun Vijayakumar

Electronic Theses and Dissertations

The increasing demand for efficient energy systems in the last decade has brought about the development of advanced sensor systems that utilize advance detection methods to help in preventive maintenance of these essential systems. These usually are needed in hard to access environments where conditions are extreme and unfit for human interaction. Thin film based sensors deposited directly on the surfaces exposed to harsh environments can serve as ideal means of measuring the temperature of the component during operation. They provide the basic advantage of proximity to the surface and hence accurate measurement of the surface temperature. The low mass …

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On Advanced Template-Based Interpretation As Applied To Intention Recognition In A Strategic Environment, Cameron Akridge Jan 2007

On Advanced Template-Based Interpretation As Applied To Intention Recognition In A Strategic Environment, Cameron Akridge

Electronic Theses and Dissertations

An area of study that has received much attention over the past few decades is simulations involving threat assessment in military scenarios. Recently, much research has emerged concerning the recognition of troop movements and formations in non-combat simulations. Additionally, there have been efforts towards the detection and assessment of various types of malicious intentions. One such work by Akridge addressed the issue of Strategic Intention Recognition, but fell short in the detection of tactics that it could not detect without somehow manipulating the environment. Therefore, the aim of this thesis is to address the problem of recognizing an opponent's intent …

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Integrated Topologies And Digital Control For Satellite Power Management And Distribution Systems, Hussam Al-Atrash Jan 2007

Integrated Topologies And Digital Control For Satellite Power Management And Distribution Systems, Hussam Al-Atrash

Electronic Theses and Dissertations

This work is focused on exploring advanced solutions for space power management and distribution (PMAD) systems. As spacecraft power requirements continue to increase, paralleled by the pressures for reducing cost and overall system weight, power electronics engineers will continue to face major redesigns of the space power systems in order to meet such challenges. Front-end PMAD systems, used to interface the solar sources and battery backup to the distribution bus, need to be designed with increased efficiency, reliability, and power density. A new family of integrated single-stage power converter structures is introduced here. This family allows the interface and control …

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Reviewing The Effects Of Alternative Fuels, Average Speed And Idling Time On Emissions From Orange County School Bus Fleet, Ali Bayat Jan 2007

Reviewing The Effects Of Alternative Fuels, Average Speed And Idling Time On Emissions From Orange County School Bus Fleet, Ali Bayat

Electronic Theses and Dissertations

Orange County, FL has been experiencing ozone concentrations in the past several years which in some cases exceeded the national and state standards. The high concentration of ground level ozone can cause a variety of health problems including chest pain, coughing, throat irritation, and congestion or it can worsen bronchitis, emphysema, and asthma. Other effects include reduction of agricultural crop and commercial forest yields, lower growth and survivability of tree seedlings, and higher susceptibility of plant to diseases, pests and other stresses such as harsh weather. The ozone generation rate is directly related to the ambient concentration of nitrogen oxides …

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Design And Implementation Of A Hardware Level Content Networking Front End Device, Jeremy Layne Buboltz Jan 2007

Design And Implementation Of A Hardware Level Content Networking Front End Device, Jeremy Layne Buboltz

Electronic Theses and Dissertations

The bandwidth and speed of network connections are continually increasing. The speed increase in network technology is set to soon outpace the speed increase in CMOS technology. This asymmetrical growth is beginning to causing software applications that once worked with then current levels of network traffic to flounder under the new high data rates. Processes that were once executed in software now have to be executed, partially if not wholly in hardware. One such application that could benefit from hardware implementation is high layer routing. By allowing a network device to peer into higher layers of the OSI model, the …

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Spacecraft Loads Predictionvia Sensitivity Analysis And Optimization, Tom Braswell Jan 2007

Spacecraft Loads Predictionvia Sensitivity Analysis And Optimization, Tom Braswell

Electronic Theses and Dissertations

Discrepancies between the predicted responses of a finite element analysis (FEA) and reference data from test results arise for many reasons. Some are due to measurement errors, such as inaccurate sensors, noise in the acquisition system or environmental effects. Some are due to analyst errors precipitated by a lack of familiarity with the modeling or solver software. Still others are introduced by uncertainty in the governing physical relations (linear versus non-linear behavior), boundary conditions or the element material/geometrical properties. It is the uncertainty effects introduced by this last group that this study seeks to redress. The objective is the obtainment …

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Dimesionality Aspects Of Nano Micro Integrated Metal Oxide Based Early Stage Leak Detection Room Temperature Hydrogen Sensor, Sameer Arun Deshpande Jan 2007

Dimesionality Aspects Of Nano Micro Integrated Metal Oxide Based Early Stage Leak Detection Room Temperature Hydrogen Sensor, Sameer Arun Deshpande

Electronic Theses and Dissertations

Detection of explosive gas leaks such as hydrogen (H2) becomes key element in the wake of counter-terrorism threats, introduction of hydrogen powered vehicles and use of hydrogen as a fuel for space explorations. In recent years, a significant interest has developed on metal oxide nanostructured sensors for the detection of hydrogen gas. Gas sensors properties such as sensitivity, selectivity and response time can be enhanced by tailoring the size, the shape, the structure and the surface of the nanostructures. Sensor properties (sensitivity, selectivity and response time) are largely modulated by operating temperature of the device. Issues like instability of nanostructures …

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Four Terminal Junction Field-Effect Transistor Model For Computer-Aided Design, Hao Ding Jan 2007

Four Terminal Junction Field-Effect Transistor Model For Computer-Aided Design, Hao Ding

Electronic Theses and Dissertations

A compact model for four-terminal (independent top and bottom gates) junction field-effect transistor (JFET) is presented in this dissertation. The model describes the steady-state characteristics with a unified equation for all bias conditions that provides a high degree of accuracy and continuity of conductance, which are important for predictive analog circuit simulations. It also includes capacitance and leakage equations. A special capacitance drop-off phenomenon at the pinch-off region is studies and modeled. The operations of the junction fieldeffect transistor (JFET) with an oxide top-gate and full oxide isolation are analyzed, and a semi-physical compact model is developed. The effects of …

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High Pressure Testing Of Composite Solid Rocket Propellant Mixtures: Burner Facility Characterization, Rodolphe Valentin Carro Jan 2007

High Pressure Testing Of Composite Solid Rocket Propellant Mixtures: Burner Facility Characterization, Rodolphe Valentin Carro

Electronic Theses and Dissertations

Much Research on composite solid propellants has been performed over the past few decades and much progress has been made, yet many of the fundamental processes are still unknown, and the development of new propellants remains highly empirical. Ways to enhance the performance of solid propellants for rocket and other applications continue to be explored experimentally, including the effects of various additives and the impact of fuel and oxidizer particle sizes on burning behavior. One established method to measure the burning rate of composite propellant mixtures in a controlled laboratory setting is to use a constant-volume pressure vessel, or strand …

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Optimizing The High Dynamic Range Imaging Pipeline, Ahmet Oguz Akyuz Jan 2007

Optimizing The High Dynamic Range Imaging Pipeline, Ahmet Oguz Akyuz

Electronic Theses and Dissertations

High dynamic range (HDR) imaging is a rapidly growing field in computer graphics and image processing. It allows capture, storage, processing, and display of photographic information within a scene-referred framework. The HDR imaging pipeline consists of the major steps an HDR image is expected to go through from capture to display. It involves various techniques to create HDR images, pixel encodings and file formats for storage, tone mapping for display on conventional display devices and direct display on HDR capable screens. Each of these stages have important open problems, which need to be addressed for a smoother transition to an …

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Signal Processing Of An Ecg Signal In The Presence Of A Strong Static Magnetic Field, Aditya Gupta Jan 2007

Signal Processing Of An Ecg Signal In The Presence Of A Strong Static Magnetic Field, Aditya Gupta

Electronic Theses and Dissertations

This dissertation addresses the problem of elevation of the T wave of an electrocardiogram (ECG) signal in the magnetic resonance imaging (MRI). In the MRI, due to the strong static magnetic field the interaction of the blood flow with this strong magnetic field induces a voltage in the body. This voltage appears as a superimposition at the locus of the T wave of the ECG signal. This looses important information required by the doctors to interpret the ST segment of the ECG and detect diseases such as myocardial infarction. This dissertation aims at finding a solution to the problem of …

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Studies Of A Quantum Scheduling Algorithm And On Quantum Error Correction, Feng Lu Jan 2007

Studies Of A Quantum Scheduling Algorithm And On Quantum Error Correction, Feng Lu

Electronic Theses and Dissertations

Quantum computation has been a rich field of study for decades because it promises possible spectacular advances, some of which may run counter to our classically rooted intuitions. At the same time, quantum computation is still in its infancy in both theoretical and practical areas. Efficient quantum algorithms are very limited in number and scope; no real breakthrough has yet been achieved in physical implementations. Grover's search algorithm can be applied to a wide range of problems; even problems not generally regarded as searching problems can be reformulated to take advantage of quantum parallelism and entanglement leading to algorithms which …

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Network Performance Management Using Application-Centric Key Performance Indicators, Susan Mcgill Jan 2007

Network Performance Management Using Application-Centric Key Performance Indicators, Susan Mcgill

Electronic Theses and Dissertations

The Internet and intranets are viewed as capable of supplying "Anything, Anywhere, Anytime" and e-commerce, e-government, e-community, and military C4I are now deploying many and varied applications to serve their needs. Network management is currently centralized in operations centers. To assure customer satisfaction with the network performance they typically plan, configure and monitor the network devices to insure an excess of bandwidth, that is overprovision. If this proves uneconomical or if complex and poorly understood interactions of equipment, protocols and application traffic degrade performance creating customer dissatisfaction, another more application-centric, way of managing the network will be needed. This research …

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Learning Human Behavior From Observation For Gaming Applications, Christopher Moriarty Jan 2007

Learning Human Behavior From Observation For Gaming Applications, Christopher Moriarty

Electronic Theses and Dissertations

The gaming industry has reached a point where improving graphics has only a small effect on how much a player will enjoy a game. One focus has turned to adding more humanlike characteristics into computer game agents. Machine learning techniques are being used scarcely in games, although they do offer powerful means for creating humanlike behaviors in agents. The first person shooter (FPS), Quake 2, is an open source game that offers a multi-agent environment to create game agents (bots) in. This work attempts to combine neural networks with a modeling paradigm known as context based reasoning (CxBR) to create …

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Exploring The Potential Of Combining Ramp Metering And Variable Speed Limit Strategies For Alleviating Real-Time Crash Risk On Urban Freeways, Kirolos Maged Haleem Jan 2007

Exploring The Potential Of Combining Ramp Metering And Variable Speed Limit Strategies For Alleviating Real-Time Crash Risk On Urban Freeways, Kirolos Maged Haleem

Electronic Theses and Dissertations

Research recently conducted at the University of Central Florida involving crashes on Interstate-4 in Orlando, Florida has led to the creation of new statistical and neural networks models that are capable of determining the crash risk on the freeway (Abdel-Aty et al., 2004; 2005, Pande and Abdel-Aty, 2006). These models are able to calculate rear-end and lane-change crash risks along the freeway in real-time through the use of static information at various locations along the freeway as well as real-time traffic data obtained by loop detectors. Since these models use real-time traffic data, they are capable of calculating rear-end and …

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Urban Infilling Impacts On Florida Solid Waste Facilities, Ravi Chander Nalamothu Jan 2007

Urban Infilling Impacts On Florida Solid Waste Facilities, Ravi Chander Nalamothu

Electronic Theses and Dissertations

Increasing urbanization in the US is leading to development or re-development of lands adjacent to solid waste facilities and these lands are being considered for residential communities and commercial projects. Thus, the potential for nuisance complaints against the pre-existing solid waste facility operations has become an increasing reality. The objective of this study was to develop a methodology to gather scientific and quantifiable data related to potential nuisances caused by landfills to determine setbacks and buffer zones near landfill and transfer station operations. Appropriate recommendations for these setbacks were made from case studies conducted at two landfills in Florida. The …

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Mechanisms Of Lifetime Improvement In Thermal Barrier Coatings With Hf And/Or Y Modification Of Cmsx-4 Superalloy Substrates, Jing Liu Jan 2007

Mechanisms Of Lifetime Improvement In Thermal Barrier Coatings With Hf And/Or Y Modification Of Cmsx-4 Superalloy Substrates, Jing Liu

Electronic Theses and Dissertations

In modern turbine engines for propulsion and energy generation, thermal barrier coating (TBCs) protect hot-section blades and vanes, and play a critical role in enhancing reliability, durability and operation efficiency. In this study, thermal cyclic lifetime and microstructural degradation of electron beam physical vapor deposited (EB-PVD) Yttria Stabilized Zirconia (YSZ) with (Ni,Pt)Al bond coat and Hf- and/or Y- modified CMSX-4 superalloy substrates were examined. Thermal cyclic lifetime of TBCs was measured using a furnace thermal cycle test that consisted of 10-minute heat-up, 50-minute dwell at 1135C, and 10-minute forced-air-quench. TBC lifetime was observed to improve from 600 cycles to over …

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An Algorithm For Determining Satellite Attitude By Comparing Physical Feature Models To Edges Detected In Satellite Or Ground-Based Telescope Imagery, Eric Brian Reinhart Jan 2007

An Algorithm For Determining Satellite Attitude By Comparing Physical Feature Models To Edges Detected In Satellite Or Ground-Based Telescope Imagery, Eric Brian Reinhart

Electronic Theses and Dissertations

This thesis discusses the development and performance of an algorithm created to calculate satellite attitude based on the comparison of satellite "physical feature" models to information derived from edge detection performed on imagery of the satellite. The quality of this imagery could range from the very clear, close-up imagery that may come from an unmanned satellite servicing mission to the faint, unclear imagery that may come from a ground-based telescope investigating a satellite anomaly. Satellite "physical feature" models describe where an edge is likely to appear in an image. These are usually defined by physical edges on the structure of …

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Fate Of Nitrogen And Phosphorus Species From A Black And Goldtm Nugget Mix In A Laboratoy Column Simulated Septic Tank Drainfiel, Timir Shah Jan 2007

Fate Of Nitrogen And Phosphorus Species From A Black And Goldtm Nugget Mix In A Laboratoy Column Simulated Septic Tank Drainfiel, Timir Shah

Electronic Theses and Dissertations

The presence of nitrates and phosphorus in ground water is a worldwide problem. A septic tank with drainfield that is conventionally designed does not typically remove nitrogen in the form of nitrates. The main risks are in "Blue baby" syndrome and suspected carcinogenic effect of nitrates on humans and the nutrient enrichment of receiving waters. In some areas nitrate and phosphorus removal are essentially required. Thus the information in this report concentrates on using media in the drainfield for the removal of nitrogen and phosphorus. Extensive work has been conducted in the past few decades in order to find suitable …

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Image-Space Approach To Real-Time Realistic Rendering, Musawir Shah Jan 2007

Image-Space Approach To Real-Time Realistic Rendering, Musawir Shah

Electronic Theses and Dissertations

One of the main goals of computer graphics is the fast synthesis of photorealistic image of virtual 3D scenes. The work presented in this thesis addresses this goal of speed and realism. In real-time realistic rendering, we encounter certain problems that are difficult to solve in the traditional 3-dimensional geometric space. We show that using an image-space approach can provide effective solutions to these problems. Unlike geometric space algorithms that operate on 3D primitives such as points, edges, and polygons, image-space algorithms operate on 2D snapshot images of the 3D geometric data. Operating in image-space effectively decouples the geometric complexity …

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An Economic Framework For Resource Management And Pricing In Wireless Networks With Competitive Service Providers, Shamik Sengupta Jan 2007

An Economic Framework For Resource Management And Pricing In Wireless Networks With Competitive Service Providers, Shamik Sengupta

Electronic Theses and Dissertations

A paradigm shift from static spectrum allocation to dynamic spectrum access (DSA) is becoming a reality due to the recent advances in cognitive radio, wide band spectrum sensing, and network aware real--time spectrum access. It is believed that DSA will allow wireless service providers (WSPs) the opportunity to dynamically access spectrum bands as and when they need it. Moreover, due to the presence of multiple WSPs in a region, it is anticipated that dynamic service pricing would be offered that will allow the end-users to move from long-term service contracts to more flexible short-term service models. In this research, we …

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