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

Digital Commons Network

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

Articles 31 - 60 of 152

Full-Text Articles in Entire DC Network

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 …


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 …


Heat Transfer In Multi-Layer Energetic Nanofilm On Composites Substrate, Manesh Navid Amini Jan 2007

Heat Transfer In Multi-Layer Energetic Nanofilm On Composites Substrate, Manesh Navid Amini

Electronic Theses and Dissertations

The main purpose of this work is the physical understanding and the numerical description of the reaction of the dense metastable intermolecular composition (MIC). Energy density of MIC is much higher than conventional energetic material; therefore, MIC finds more applications in the propellant and explosive system. The physical model includes the speed of propagation and rate of reaction, and the relationship between the layer thickness, heat rate, and length of the flame based on physical model. In Part I of this thesis, a one-dimensional model based on Weihs was developed for 20 pairs of a multi-layer of aluminum and copper …


Discussion On Effective Restoration Of Oral Speech Using Voice Conversion Techniques Based On Gaussian Mixture Modeling, Gustavo Alverio Jan 2007

Discussion On Effective Restoration Of Oral Speech Using Voice Conversion Techniques Based On Gaussian Mixture Modeling, Gustavo Alverio

Electronic Theses and Dissertations

Today's world consists of many ways to communicate information. One of the most effective ways to communicate is through the use of speech. Unfortunately many lose the ability to converse. This in turn leads to a large negative psychological impact. In addition, skills such as lecturing and singing must now be restored via other methods. The usage of text-to-speech synthesis has been a popular resolution of restoring the capability to use oral speech. Text to speech synthesizers convert text into speech. Although text to speech systems are useful, they only allow for few default voice selections that do not represent …


Modeling Free Chlorine And Chloramine Decay In A Pilot Distribution System, Jorge Miguel Arevalo Jan 2007

Modeling Free Chlorine And Chloramine Decay In A Pilot Distribution System, Jorge Miguel Arevalo

Electronic Theses and Dissertations

The purpose of this study was to identify the effect that water quality, pipe material, pipe size, flow conditions and the use of corrosion inhibitors would have on the rate of free chlorine and chloramine decay in distribution systems. Empirical models were developed to predict the disinfectant residual concentration with time based on the parameters that affected it. Different water treatment processes were used to treat groundwater and surface water to obtain 7 types of finished waters with a wide range of water quality characteristics. The groundwater was treated either by conventional treatment by aeration (G1) or softening (G2) or …


Medium Access Control Protocols And Routing Algorithms For Wireless Sensor Networks, Anirban Bag Jan 2007

Medium Access Control Protocols And Routing Algorithms For Wireless Sensor Networks, Anirban Bag

Electronic Theses and Dissertations

In recent years, the development of a large variety of mobile computing devices has led to wide scale deployment and use of wireless ad hoc and sensor networks. Wireless Sensor Networks consist of battery powered, tiny and cheap "motes", having sensing and wireless communication capabilities. Although wireless motes have limited battery power, communication and computation capabilities, the range of their application is vast. In the first part of the dissertation, we have addressed the specific application of Biomedical Sensor Networks. To solve the problem of data routing in these networks, we have proposed the Adaptive Least Temperature Routing (ALTR) algorithm …


Construction Specifications And Analysis Of Rehabilitation Techniques Of Pervious Concrete Pavement, Craig Ballock Jan 2007

Construction Specifications And Analysis Of Rehabilitation Techniques Of Pervious Concrete Pavement, Craig Ballock

Electronic Theses and Dissertations

The primary objective of this study is to evaluate the clogging potential of installed pervious concrete systems, to analyze rehabilitation techniques and develop construction specifications for the construction of portland cement pervious concrete specific to the state of Florida. Currently, a consistent statewide policy has not been established in reference to credit for storage volume within the voids in pervious concrete and the coarse aggregate base. For this reason a current and updated assessment of pervious pavement is needed to benefit from the advantages of pervious pavement use in low traffic volume areas. Initially by modeling a pervious concrete system …


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 …


Collaborative Context-Based Reasoning, Gilbert Barrett Jan 2007

Collaborative Context-Based Reasoning, Gilbert Barrett

Electronic Theses and Dissertations

This dissertation explores modeling collaborative behavior, based on Joint Intentions Theory (JIT), in Context-Based Reasoning (CxBR). Context-Based Reasoning is one of several contextual reasoning paradigms. And, Joint Intentions Theory is the definitive semantic framework for collaborative behaviors. In order to formalize collaborative behaviors in CxBR based on JIT, CxBR is first described in terms of the more popular Belief, Desire, and Intention (BDI) model. Once this description is established JIT is used as a basis for the formalism for collaborative behavior in CxBR. The hypothesis of this dissertation is that this formalism allows for effective collaborative behaviors in CxBR. Additionally, …


Soft Switching Multi-Resonant Forward Converter Dc To Dc Application For Communications Equipment, David Marlin Bills Jan 2007

Soft Switching Multi-Resonant Forward Converter Dc To Dc Application For Communications Equipment, David Marlin Bills

Electronic Theses and Dissertations

In the field of power electronics there is always a push to create smaller and more efficient power conversion systems. This push is driven by the industry that uses the power systems, and can be realized by new semiconductor devices or new techniques. This examination describes a novel technique for a small and highly efficient method of converting relatively high DC voltage to a very low voltage for use in the telecommunications industry. A modification to the standard Forward Resonant converter results in improvements in component stress, system efficiency, response time, and control circuitry. This examination describes background information needed …


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 …


Tunable Nanostructure Anti-Reflective Coatings, Erik Brinley Jan 2007

Tunable Nanostructure Anti-Reflective Coatings, Erik Brinley

Electronic Theses and Dissertations

Research was conducted on broadband, anti-reflective coatings for fused silica and chalcogenide substrates in the infrared region of light. Using chemical preparation to create nano-porous through nano-particle based sol-gel solutions, the alteration of optical properties including refractive index and optical thickness was conducted. The nano-particles can modify the coating surface to allow only zero-order diffracted wave propagation reducing scattering while a partially graded profile of refractive index due surface evaporation lessened the precise phase relations of typical homogeneous coatings. My study of silica and titania sol-gel, and hybrid mixtures of the two were used to obtain the optical properties of …


Identification And Suitability Of A Non-Anthropomorphic Meta-Language Framework In Military Applications, Gilbert Cardona Jan 2007

Identification And Suitability Of A Non-Anthropomorphic Meta-Language Framework In Military Applications, Gilbert Cardona

Electronic Theses and Dissertations

Humans carry mental models concerning the behaviors, looks, and operation of products, tools, and items used in their daily lives. When these items do not fit a user's conceptual model confusion and inefficiency occur. There are four basic types of mental models based on interactive activities: 1) instructing, 2) conversing, 3) manipulating and navigating, and 4) exploring and browsing. This thesis will focus on the conversing conceptual model and its application to communications between human-agent teams to best fit a user's mental model for that communication. A non-anthropomorphic framework does not exist for use in military applications such as; target …


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 …


Comparison Of Sparse Coding And Jpeg Coding Schemes For Blurred Retinal Images., Balaji Chandrasekaran Jan 2007

Comparison Of Sparse Coding And Jpeg Coding Schemes For Blurred Retinal Images., Balaji Chandrasekaran

Electronic Theses and Dissertations

Overcomplete representations are currently one of the highly researched areas especially in the field of signal processing due to their strong potential to generate sparse representation of signals. Sparse representation implies that given signal can be represented with components that are only rarely significantly active. It has been strongly argued that the mammalian visual system is highly related towards sparse and overcomplete representations. The primary visual cortex has overcomplete responses in representing an input signal which leads to the use of sparse neuronal activity for further processing. This work investigates the sparse coding with an overcomplete basis set representation which …


Developing A Spatial Interface For Information Visualization And Management In A Crisis Response Scenario, Anthony Costello Jan 2007

Developing A Spatial Interface For Information Visualization And Management In A Crisis Response Scenario, Anthony Costello

Electronic Theses and Dissertations

The focus of this study was to investigate how a spatial interface can be effectively utilized to support information presentation and information integration via human-centric data visualization, leading to decreased cognitive load, more accurate situation awareness, and subsequently, improved task performance. In high tempo, information intensive environments like those managed by an emergency operations center (EOC), information organization tools are essential. Though users can be trained to use conventional email software applications efficiently, the constraints of the information management paradigms inherent to conventional systems may limit a user's ability to gather context and create an accurate picture of the situation. …


Quantification Of Emissions From Lawn And Garden Equipment In Central Florida, Megan Leigh Crum Jan 2007

Quantification Of Emissions From Lawn And Garden Equipment In Central Florida, Megan Leigh Crum

Electronic Theses and Dissertations

The objective of this study was to evaluate the practical limits of EPA's NONROAD 2005 to accurately simulate Central Florida conditions, especially with regard to lawn and garden equipment. In particular we investigated a NONROAD emission inventory using default inputs and then created a locally specific emission inventory. These emission inventories were prepared for Orange, Osceola, and Seminole county and focused only on the VOC and NOx emissions caused by lawn and garden equipment. The model was manipulated to assess its ability to represent this specific category of nonroad equipment for a given airshed first by running a base case …


All-Optical Regeneration For Phase-Shift Keyed Optical Communication Systems, Kevin Croussore Jan 2007

All-Optical Regeneration For Phase-Shift Keyed Optical Communication Systems, Kevin Croussore

Electronic Theses and Dissertations

All-optical signal processing techniques for phase-shift keyed (PSK) systems were developed theoretically and demonstrated experimentally. Nonlinear optical effects in fibers, in particular four-wave mixing (FWM) that occurs via the ultra-fast Kerr nonlinearity, offer a flexible framework within which numerous signal processing functions can be accomplished. This research has focused on the regenerative capabilities of various FWM configurations in the context of processing PSK signals. Phase-preserving amplitude regeneration, phase regeneration, and phase-regenerative wavelength conversion are analyzed and demonstrated experimentally. The single-pump phase-conjugation process was used to regenerate RZ-DPSK pulse amplitudes with different input noise distributions, and the impact on output phase …


Control And Stabilization Of Laser Plasmasources For Euv Lithography, Jose Cunado Jan 2007

Control And Stabilization Of Laser Plasmasources For Euv Lithography, Jose Cunado

Electronic Theses and Dissertations

Extreme Ultraviolet (EUV) sources rely on droplet laser plasmas for EUV generation. These sources consist of a small (30 µm diameter) droplet which is excited into plasma emitting EUV around 13.5 nm, the industry’s chosen wavelength for EUV lithography (EUVL). These sources are the best candidates for the commercialization of EUVL allowing mass production of computer chips with 32 nm or even smaller feature size. However, the biggest challenges which EUV source developers encounter today are the issues of conversion efficiency (CE) and debris. In order to satisfy the technology requirements, the source will need to meet high levels of …


Understanding The Low Temperature Electrical Propertiesof Nanocrystalline Sno2 For Gas Sensor Applications, Christina Drake Jan 2007

Understanding The Low Temperature Electrical Propertiesof Nanocrystalline Sno2 For Gas Sensor Applications, Christina Drake

Electronic Theses and Dissertations

Nanocrystalline metal/metal oxide is an important class of transparent and electronic materials due to its potential use in many applications, including gas sensors. At the nanoscale, many of the phenomena observed that give nanocrystalline semiconducting oxide enhanced performance as a gas sensor material over other conventional engineering materials is still poorly understood. This study is aimed at understanding the low temperature electrical and chemical properties of nanocrystalline SnO2 that makes it suitable for room temperature gas detectors. Studies were carried out in order to understand how various synthesis methods affect the surfaces on the nano-oxides, interactions of a target gas …


Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge Jan 2007

Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge

Electronic Theses and Dissertations

Liquid crystal (LC) materials have been widely applied in electro-optical devices, among which display is the most successful playground and numerous new applications in photonic areas (such as laser beam steering devices) are also emerging. To well guide the device design for optimum performance, accurate modeling is of prior and practical importance. Generally, the modeling of LC devices includes two parts in sequence: accurate LC molecule deformation extraction under external electric fields and optical calculation thereafter for the corresponding electro-optical behaviors. In this dissertation, first, hybrid finite element method and finite difference method are developed to minimize the free energy …


Learning, Detection, Representation, Indexing And Retrieval Of Multi-Agent Events In Videos, Asaad Hakeem Jan 2007

Learning, Detection, Representation, Indexing And Retrieval Of Multi-Agent Events In Videos, Asaad Hakeem

Electronic Theses and Dissertations

The world that we live in is a complex network of agents and their interactions which are termed as events. An instance of an event is composed of directly measurable low-level actions (which I term sub-events) having a temporal order. Also, the agents can act independently (e.g. voting) as well as collectively (e.g. scoring a touch-down in a football game) to perform an event. With the dawn of the new millennium, the low-level vision tasks such as segmentation, object classification, and tracking have become fairly robust. But a representational gap still exists between low-level measurements and high-level understanding of video …


Eino: An Intelligent Tutor For The University Of Central Florida Infinity Web Applets, James Hollister Jan 2007

Eino: An Intelligent Tutor For The University Of Central Florida Infinity Web Applets, James Hollister

Electronic Theses and Dissertations

This study investigated the various methods involved in creating an intelligent tutor for the University of Central Florida Infinity Web Applets (UCF Infinity Web Applets). After conducting research into various methods, two major methods emerged and they are: solving the problem for the student and helping the student when they become stymied and unable to solve the problem. A storyboard was created to show the interactions of the student and system along with a list of features that were desired to be included in the tutoring system. From the storyboard and list of features, an architecture was created to handle …


Low Temperature Nitife Shape Memory Alloys: Actuator Engineering And Investigation Of Deformation Mechanisms Using In Situ Neutr, Vinu Krishnan Jan 2007

Low Temperature Nitife Shape Memory Alloys: Actuator Engineering And Investigation Of Deformation Mechanisms Using In Situ Neutr, Vinu Krishnan

Electronic Theses and Dissertations

Shape memory alloys are incorporated as actuator elements due to their inherent ability to sense a change in temperature and actuate against external loads by undergoing a shape change as a result of a temperature-induced phase transformation. The cubic so-called austenite to the trigonal so-called R-phase transformation in NiTiFe shape memory alloys offers a practical temperature range for actuator operation at low temperatures, as it exhibits a narrow temperature-hysteresis with a desirable fatigue response. Overall, this work is an investigation of selected science and engineering aspects of low temperature NiTiFe shape memory alloys. The scientific study was performed using in …


Using Electrochemical Monitoring To Predict Metal Release In Drinking Water Distribution Systems, Rajendra D. Vaidya Jan 2007

Using Electrochemical Monitoring To Predict Metal Release In Drinking Water Distribution Systems, Rajendra D. Vaidya

Electronic Theses and Dissertations

Corrosion of distribution system piping and home plumbing materials is a major concern in the water community. Iron release adverse affects aesthetic water quality and the release of copper and lead is regulated by the Lead and Copper rule (LCR) and can adversely affect consumer health. Corrosion control is typically done by pH regulation and/or addition of corrosion inhibitors. Monitoring of corrosion control is typically done after the fact by monitoring metal release, functional group concentration of the selected chemical species or water quality. Hence, the associated laboratory analyses create a significant delay prior to the assessment of corrosion in …


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 …


Novel Facial Image Recognition Techniques Employing Principal Component Analysis, Moataz Mahmoud Abdelwahab Jan 2007

Novel Facial Image Recognition Techniques Employing Principal Component Analysis, Moataz Mahmoud Abdelwahab

Electronic Theses and Dissertations

Recently, pattern recognition/classification has received considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, and face recognition, etc. This study contributes novel techniques for facial image recognition based on the Two dimensional principal component analysis in the transform domain. These algorithms reduce the storage requirements by an order of magnitude and the computational complexity by a factor of 2 while maintaining the excellent recognition accuracy of the recently reported methods. The proposed recognition systems employ different structures, multicriteria and multitransform. In addition, principal component analysis in the transform domain in conjunction with vector quantization is …


High-Intensity Ultra-Fast Laser Interaction Technologies, Robert Thomas Bernath Jan 2007

High-Intensity Ultra-Fast Laser Interaction Technologies, Robert Thomas Bernath

Electronic Theses and Dissertations

To our knowledge this is the first comprehensive study of laser-induced effects generated at intermediate distances using self-channeled femtosecond laser pulses. Studies performed were made both experimentally and theoretically with the use of novel modeling techniques. Peak laser pulse powers above 3 GW allow beam propagation without divergence for up to several kilometers. In this regime, experiments were performed at 30 meters from the laser system in a custom propagation and target range, utilizing the Laser Plasma Laboratory's Terawatt laser system. Experiments included investigations of laser ablation; electromagnetic pulsed (EMP) radiation generation over the 1-18 GHz region; shockwave formation in …


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 …


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 …