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

Engineering Commons™

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

University of Central Florida

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 2281 - 2310 of 4566

Full-Text Articles in Engineering

Feature Pruning For Action Recognition In Complex Environment, Adarsh Nagaraja Jan 2011

Feature Pruning For Action Recognition In Complex Environment, Adarsh Nagaraja

Electronic Theses and Dissertations

A significant number of action recognition research efforts use spatio-temporal interest point detectors for feature extraction. Although the extracted features provide useful information for recognizing actions, a significant number of them contain irrelevant motion and background clutter. In many cases, the extracted features are included as is in the classification pipeline, and sophisticated noise removal techniques are subsequently used to alleviate their effect on classification. We introduce a new action database, created from the Weizmann database, that reveals a significant weakness in systems based on popular cuboid descriptors. Experiments show that introducing complex backgrounds, stationary or dynamic, into the video …


Heat Transfer In A Coupled Impingement-Effusion Cooling System, Mark W. Miller Jan 2011

Heat Transfer In A Coupled Impingement-Effusion Cooling System, Mark W. Miller

Electronic Theses and Dissertations

Gas turbine engines are prevalent in the today’s aviation and power generation industries. The majority of commercial aircraft use a turbofan gas turbine engines. Gas turbines used for power generation can achieve thermodynamic efficiencies as high as 60% when coupled with a steam turbine as part of a combined cycle. The success of gas turbines is a direct result of a half century’s development of the technology necessary to create such efficient, powerful, and reliable machines. One key area of technical advancement is the turbine cooling system. In short, increasing the turbine inlet temperature leads to a rise in cycle …


Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera Jan 2011

Ray Collection Bounding Volume Hierarchy, Kris Krishna Rivera

Electronic Theses and Dissertations

This thesis presents Ray Collection BVH, an improvement over a current day Ray Tracing acceleration structure to both build and perform the steps necessary to efficiently render dynamic scenes. Bounding Volume Hierarchy (BVH) is a commonly used acceleration structure, which aides in rendering complex scenes in 3D space using Ray Tracing by breaking the scene of triangles into a simple hierarchical structure. The algorithm this thesis explores was developed in an attempt at accelerating the process of both constructing this structure, and also using it to render these complex scenes more efficiently. The idea of using "ray collection" as a …


Techniques For Boosting The Performance In Content-Based Image Retrieval Systems, Ning Yu Jan 2011

Techniques For Boosting The Performance In Content-Based Image Retrieval Systems, Ning Yu

Electronic Theses and Dissertations

Content-Based Image Retrieval has been an active research area for decades. In a CBIR system, one or more images are used as query to search for similar images. The similarity is measured on the low level features, such as color, shape, edge, texture. First, each image is processed and visual features are extract. Therefore each image becomes a point in the feature space. Then, if two images are close to each other in the feature space, they are considered similar. That is, the k nearest neighbors are considered the most similar images to the query image. In this K-Nearest Neighbor …


Modeling Human Group Behavior In Virtual Worlds, Fahad Shah Jan 2011

Modeling Human Group Behavior In Virtual Worlds, Fahad Shah

Electronic Theses and Dissertations

Virtual worlds and massively-multiplayer online games are rich sources of information about large-scale teams and groups, offering the tantalizing possibility of harvesting data about group formation, social networks, and network evolution. They provide new outlets for human social interaction that differ from both face-to-face interactions and non-physically-embodied social networking tools such as Facebook and Twitter. We aim to study group dynamics in these virtual worlds by collecting and analyzing public conversational patterns of users grouped in close physical proximity. To do this, we created a set of tools for monitoring, partitioning, and analyzing unstructured conversations between changing groups of participants …


Purge And Secondary Flow Interaction Control By Means Of Platform Circumferential Contouring, Melissa Harris Jan 2011

Purge And Secondary Flow Interaction Control By Means Of Platform Circumferential Contouring, Melissa Harris

Electronic Theses and Dissertations

This study presents an attempt to reduce the losses produced by the purge flow in a turbine stage by incorporating circumferential platform contouring. Two contours are proposed and compared against a baseline at different levels of swirl. The computational simulations were performed using a RANS three-dimensional Computational Fluid Dynamics code with the Shear Stress Transport turbulence model. The results of steady simulations demonstrate that for the first contour, when the flow is swirled to 50% of the rim speed, the purge flow exits the cavity with less cross flow. This in turn reduces the strength of the passage vortex. However, …


An Improved Ocean Vector Winds Retrieval Approach Using C- And Ku-Band Scatterometer And Multi-Frequency Microwave Radiometer Measurements, Suleiman Odeh Alsweiss Jan 2011

An Improved Ocean Vector Winds Retrieval Approach Using C- And Ku-Band Scatterometer And Multi-Frequency Microwave Radiometer Measurements, Suleiman Odeh Alsweiss

Electronic Theses and Dissertations

This dissertation will specifically address the issue of improving the quality of satellite scatterometer retrieved ocean surface vector winds (OVW), especially in the presence of strong rain associated with tropical cyclones. A novel active/passive OVW retrieval algorithm is developed that corrects Ku-band scatterometer measurements for rain effects and then uses them to retrieve accurate OVW. The rain correction procedure makes use of independent information available from collocated multi-frequency passive microwave observations provided by a companion sensor and also from simultaneous C-band scatterometer measurements. The synergy of these active and passive measurements enables improved correction for rain effects, which enhances the …


Effective Task Transfer Through Indirect Encoding, Phillip Verbancsics Jan 2011

Effective Task Transfer Through Indirect Encoding, Phillip Verbancsics

Electronic Theses and Dissertations

An important goal for machine learning is to transfer knowledge between tasks. For example, learning to play RoboCup Keepaway should contribute to learning the full game of RoboCup soccer. Often approaches to task transfer focus on transforming the original representation to fit the new task. Such representational transformations are necessary because the target task often requires new state information that was not included in the original representation. In RoboCup Keepaway, changing from the 3 vs. 2 variant of the task to 4 vs. 3 adds state information for each of the new players. In contrast, this dissertation explores the idea …


Viability Study Of A Residential Integrated Stormwater, Graywater, And Wastewater Treatment System At Florida's Showcase Green Envirohome, Matthew Allen Goolsby Jan 2011

Viability Study Of A Residential Integrated Stormwater, Graywater, And Wastewater Treatment System At Florida's Showcase Green Envirohome, Matthew Allen Goolsby

Electronic Theses and Dissertations

The subject of water scarcity and the rate of water consumption has become popular topics over the last few decades. It is possible that society may consume or contaminate much of the remaining readily available water if there is not a paradigm shift. This deep rooted concern has prompted investigations to identify alternative water use and treatment methods. Within this report, information is presented from the use of innovative water harvesting and on-site sewage treatment and disposal systems (OSTDS) at Florida’s Showcase Green Envirohome (FSGE.net), while also addressing low impact development (LID) practices. FSGE is a residential home that demonstrates …


Nonlinear Estimation And Control For Assistive Robots, Zhao Wang Jan 2011

Nonlinear Estimation And Control For Assistive Robots, Zhao Wang

Electronic Theses and Dissertations

In this thesis, we document the progress in the estimation and control design of a smart assistive robot arm that can provide assistance during activities of daily living to the elderly and/or users with disabilities. Interaction with the environment is made challenging by the kinematic uncertainty in the robot, imperfect sensor calibration, limited view of angle as well as the fact that most activities of daily living are generally required to be performed in unstructured environments. For monocular visual systems, range (or depth) information is always crucial for target modeling and system control design. In the first part of my …


Resource Banking An Energy-Efficient, Run-Time Adaptive Processor Design Technique, Jacob Staples Jan 2011

Resource Banking An Energy-Efficient, Run-Time Adaptive Processor Design Technique, Jacob Staples

Electronic Theses and Dissertations

From the earliest and simplest scalar computation engines to modern superscalar out-oforder processors, the evolution of computational machinery during the past century has largely been driven by a single goal: performance. In today’s world of cheap, billion-plus transistor count processors and with an exploding market in mobile computing, a design landscape has emerged where energy efficiency, arguably more than any other single metric, determines the viability of a processor for a given application. The historical emphasis on performance has left modern processors bloated and over provisioned for everyday tasks in the hope that during computationally intensive periods some performance improvement …


Imaging Long-Range Orientational Order In Monolayers Of Amphiphilic Molecules With Scanning Probe Force Microscope And Liquid Crystal Optical Amplification, Wenlang Liang Jan 2011

Imaging Long-Range Orientational Order In Monolayers Of Amphiphilic Molecules With Scanning Probe Force Microscope And Liquid Crystal Optical Amplification, Wenlang Liang

Electronic Theses and Dissertations

Monolayers of amphiphilic molecules at interface provide a unique system for understanding the thermodynamic and rheological properties of quasi two-dimensional systems. They are also an excellent model accessible for studying cell membranes. The feature of longrange organization of molecular tilt azimuth in monolayers at the air/water interface is one of the most interesting findings over the past two decades, which leads to the formation rich and defined textures. By observing the changes in these textures, the transitions between tilted monolayer phases can be detected. We study the boojum and stripe textures formed in the liquid-condensed phase of pentadecanoic acid (PDA) …


Spatio-Temporal Negotiation Protocols, Yi Luo Jan 2011

Spatio-Temporal Negotiation Protocols, Yi Luo

Electronic Theses and Dissertations

Canonical problems are simplified representations of a class of real world problems. They allow researchers to compare algorithms in a standard setting which captures the most important challenges of the real world problems being modeled. In this dissertation, we focus on negotiating a collaboration in space and time, a problem with many important real world applications. Although technically a multi-issue negotiation, we show that the problem can not be represented in a satisfactory manner by previous models. We propose the "Children in the Rectangular Forest" (CRF) model as a possible canonical problem for negotiating spatio-temporal collaboration. In the CRF problem, …


Cfd Analysis Of A Uni-Directional Impulse Turbine For Wave Energy Conversion, Carlos Alberto Velez Jan 2011

Cfd Analysis Of A Uni-Directional Impulse Turbine For Wave Energy Conversion, Carlos Alberto Velez

Electronic Theses and Dissertations

Ocean energy research has grown in popularity in the past decade and has produced various designs for wave energy extraction. This thesis focuses on the performance analysis of a uni-directional impulse turbine for wave energy conversion. Uni-directional impulse turbines can produce uni-directional rotation in bi-directional flow, which makes it ideal for wave energy extraction as the motion of ocean waves are inherently bi-directional. This impulse turbine is currently in use in four of the world’s Oscillating Wave Columns (OWC). Current research to date has documented the performance of the turbine but little research has been completed to understand the flow …


Reliability Study Of Ingap/Gaas Heterojunction Bipolar Transistor Mmic Technology By Characterization, Modeling And Simulation, Xiang Liu Jan 2011

Reliability Study Of Ingap/Gaas Heterojunction Bipolar Transistor Mmic Technology By Characterization, Modeling And Simulation, Xiang Liu

Electronic Theses and Dissertations

Recent years have shown real advances of microwave monolithic integrated circuits (MMICs) for millimeter-wave frequency systems, such as wireless communication, advanced imaging, remote sensing and automotive radar systems, as MMICs can provide the size, weight and performance required for these systems. Traditionally, GaAs pseudomorphic high electron mobility transistor (pHEMT) or InP based MMIC technology has dominated in millimeter-wave frequency applications because of their high fT and fmax as well as their superior noise performance. But these technologies are very expensive. Thus, for low cost and high performance applications, InGaP/GaAs heterojunction bipolar transistors (HBTs) are quickly becoming the preferred technology to …


Labeled Sampling Consensus A Novel Algorithm For Robustly Fitting Multiple Structures Using Compressed Sampling, Carl J. Messina Jan 2011

Labeled Sampling Consensus A Novel Algorithm For Robustly Fitting Multiple Structures Using Compressed Sampling, Carl J. Messina

Electronic Theses and Dissertations

The ability to robustly fit structures in datasets that contain outliers is a very important task in Image Processing, Pattern Recognition and Computer Vision. Random Sampling Consensus or RANSAC is a very popular method for this task, due to its ability to handle over 50% outliers. The problem with RANSAC is that it is only capable of finding a single structure. Therefore, if a dataset contains multiple structures, they must be found sequentially by finding the best fit, removing the points, and repeating the process. However, removing incorrect points from the dataset could prove disastrous. This thesis offers a novel …


Data-True Characterization Of Neuronal Models, Jose Suarez Jan 2011

Data-True Characterization Of Neuronal Models, Jose Suarez

Electronic Theses and Dissertations

In this thesis, a weighted least squares approach is initially presented to estimate the parameters of an adaptive quadratic neuronal model. By casting the discontinuities in the state variables at the spiking instants as an impulse train driving the system dynamics, the neuronal output is represented as a linearly parameterized model that depends on filtered versions of the input current and the output voltage at the cell membrane. A prediction errorbased weighted least squares method is formulated for the model. This method allows for rapid estimation of model parameters under a persistently exciting input current injection. Simulation results show the …


Impurity And Interdiffusion In The Magnesium-Aluminum System, Sarah Tiffany Brennan Jan 2011

Impurity And Interdiffusion In The Magnesium-Aluminum System, Sarah Tiffany Brennan

Electronic Theses and Dissertations

Magnesium alloys offer a base of lightweight engineering materials for electronic, military and transportation applications where weight reduction is crucial for higher efficiency. Understanding fundamental diffusion behavior in Mg alloys elicits better materials properties through the optimization of processing techniques and heat treatments, whose material responses are affected by diffusion. The main objective of this study is to provide a clear, comprehensive description of the diffusion behavior in the technically important magnesium-aluminum binary metallic system. In this study, diffusion in the Mg-Al system was observed through solid diffusion couples and thin film specimens in the temperature range of 673-523K. The …


Robustness Analysis For Turbomachinery Stall Flutter, Md Moinul Forhad Jan 2011

Robustness Analysis For Turbomachinery Stall Flutter, Md Moinul Forhad

Electronic Theses and Dissertations

Flutter is an aeroelastic instability phenomenon that can result either in serious damage or complete destruction of a gas turbine blade structure due to high cycle fatigue. Although 90% of potential high cycle fatigue occurrences are uncovered during engine development, the remaining 10% stand for one third of the total engine development costs. Field experience has shown that during the last decades as much as 46% of fighter aircrafts were not mission-capable in certain periods due to high cycle fatigue related mishaps. To assure a reliable and safe operation, potential for blade flutter must be eliminated from the turbomachinery stages. …


High Linearity 5.8 Ghz Power Amplifier With An Internal Linearizer, Yiheng Wang Jan 2011

High Linearity 5.8 Ghz Power Amplifier With An Internal Linearizer, Yiheng Wang

Electronic Theses and Dissertations

A 5.8 GHz RF Power Amplifier (PA) is designed and fabricated in this work, which has very high linearity through a built-in linearizer. The PA is designed, post-layout simulated by Agilent Advanced Design System (ADS) software and fabricated by Win-Semiconductors 0.15µm pHEMT process technology. The post-layout simulation results illustrate the power amplifier can obtained an output power of 23.98 dBm, a power gain of 32.28 dB and a power added efficiency (PAE) of 29% at saturation region, the 3rd intermodulation distortion (IMD3) of -37.7 dBc at 0 dBm input power is attained when operation frequency is 5.8 GHz. We finally …


Models To Estimate Arrival Counts And Staffing Requirements In Nonstationary Queueing Systems Applied To Long Distance Road Races, Lindon P. Fairweather Jan 2011

Models To Estimate Arrival Counts And Staffing Requirements In Nonstationary Queueing Systems Applied To Long Distance Road Races, Lindon P. Fairweather

Electronic Theses and Dissertations

We examine the problem of staffing refreshment stations at a long distance road race. A race is modeled as a mixed queueing network in which the required number of servers at each service station has to be estimated. Two models to represent the progress of runners along a long distance road race course are developed. One model is a single-class model that allows a road race manager to staff service stations assuming the runners are identical to those in some historical dataset. Another model is a multi-class simulation model that allows a road race manager to simulate a race of …


2008 Emissions Inventory Of Central Florida, Jessica Leigh Ross Jan 2011

2008 Emissions Inventory Of Central Florida, Jessica Leigh Ross

Electronic Theses and Dissertations

An emissions inventory of VOCs, NOx, and CO2 was conducted for three central Florida counties – Orange, Seminole, and Osceola (OSO) – for calendar year 2008. The inventory utilized three programs: MOBILE6, NONROAD2005, and EDMS (Emissions and Dispersion Modeling System) to model on‐road mobile, non‐road mobile, and airport emissions, respectively. Remaining point and area source data was estimated from the Florida Department of Environmental Protection (FDEP) and the U.S. Environmental Protection Agency’s (U.S. EPA) 2008 emissions inventory. The previous OSO emissions inventory was done in 2002 and in the six years between inventories, there have been changes in population, commerce, …


Rain Rate Retrieval Algorithm For Aquarius/Sac-D Microwave Radiometer, Rosa Ana Menzerotolo Jan 2011

Rain Rate Retrieval Algorithm For Aquarius/Sac-D Microwave Radiometer, Rosa Ana Menzerotolo

Electronic Theses and Dissertations

Microwave radiometers are used to measure blackbody microwave emissions emitted by natural targets. Radiative transfer theory provides a well founded physical relationship between the atmosphere and surface geophysical parameters and the brightness temperature measured by these radiometers. The atmospheric brightness temperature is proportional to the integral of the microwave absorption of water vapor, oxygen, and liquid water between the top of the atmosphere and the surface. Inverse radiative transfer models use to retrieve the water vapor, cloud liquid and oxygen content in the atmosphere are very well known; however, the retrieval of rain rate in the atmosphere is still a …


Field Implementation Of Polyacrylamide For Runoff From Construction Sites, Rafiqul Islam Chowdhury Jan 2011

Field Implementation Of Polyacrylamide For Runoff From Construction Sites, Rafiqul Islam Chowdhury

Electronic Theses and Dissertations

Polyacrylamide (PAM) is often used a part of a treatment train for the treatment of stormwater to reduce its turbidity. This study investigated the application of PAM within various treatment systems for a construction site environment. The general concept is to introduce hydraulic principles when placing PAM blocks within an open channel in order to yield high mixing energies leading to high turbidity removal efficiency. The first part of the study observed energy variation using a hydraulic flume for three dissimilar configurations. The flume was ultimately used to determine which configuration would be most beneficial when transposed into field-scale conditions. …


Effect Of Acetic Or Citric Acid Ultrafiltration Recycle Streams On Coagulation Processes, Christopher C. Boyd Jan 2011

Effect Of Acetic Or Citric Acid Ultrafiltration Recycle Streams On Coagulation Processes, Christopher C. Boyd

Electronic Theses and Dissertations

Integrating ultrafiltration (UF) membranes in lieu of traditional media filters within conventional surface water coagulation-flocculation-sedimentation processes is growing in popularity. UF systems are able to produce low turbidity filtered water that meets newer drinking water standards. For typical drinking water applications, UF membranes require periodic chemically enhanced backwashes (CEBs) to maintain production; and citric acid is a common chemical used for this purpose. Problems may arise when the backwash recycle stream from a citric acid CEB is blended with raw water entering the coagulation basin, a common practice for conventional surface water plants. Citric acid is a chelating agent capable …


Optimal Detour Planning Around Blocked Construction Zones, Mutasem Jardaneh Jan 2011

Optimal Detour Planning Around Blocked Construction Zones, Mutasem Jardaneh

Electronic Theses and Dissertations

Construction zones are traffic way areas where construction, maintenance or utility work is identified by warning signs, signals and indicators, including those on transport devices that mark the beginning and end of construction zones. Construction zones are among the most dangerous work areas, with workers facing workplace safety challenges that often lead to catastrophic injuries or fatalities. In addition, daily commuters are also impacted by construction zone detours that affect their safety and daily commute time. These problems represent major challenges to construction planners as they are required to plan vehicle routes around construction zones in such a way that …


Modeling, Design And Fabrication Of Orthogonal And Psuedo-Orthogonal Frequency Coded Saw Wireless Spread Spectrum Rfid Sensor Tags, Nancy Saldanha Jan 2011

Modeling, Design And Fabrication Of Orthogonal And Psuedo-Orthogonal Frequency Coded Saw Wireless Spread Spectrum Rfid Sensor Tags, Nancy Saldanha

Electronic Theses and Dissertations

Surface acoustic wave (SAW) sensors offer a wireless, passive sensor solution for use in numerous environments where wired sensing can be expensive and infeasible. Single carrier frequency SAW sensor embodiments such as delay lines, and resonators have been used in single sensor environments where sensor identification is not a necessity. The orthogonal frequency coded (OFC) SAW sensor tag embodiment developed at UCF uses a spread spectrum approach that allows interrogation in a multi-sensor environment and provides simultaneous sensing and sensor identi- fication. The SAW device is encoded via proper design of multiple Bragg reflectors at differing frequencies. To enable accurate …


Incremental Lifecycle Validation Of Knowledge-Based Systems Through Commonkads, Feras Batarseh Jan 2011

Incremental Lifecycle Validation Of Knowledge-Based Systems Through Commonkads, Feras Batarseh

Electronic Theses and Dissertations

This dissertation introduces a novel validation method for knowledge-based systems (KBS). Validation is an essential phase in the development lifecycle of knowledge-based systems. Validation ensures that the system is valid, reliable and that it reflects the knowledge of the expert and meets the specifications. Although many validation methods have been introduced for knowledge-based systems, there is still a need for an incremental validation method based on a lifecycle model. Lifecycle models provide a general framework for the developer and a mapping technique from the system into the validation process. They support reusability, modularity and offer guidelines for knowledge engineers to …


Super-Adiabatic Combustion In Porous Media With Catalytic Enhancement For Thermoelectric Power Conversion, Kyle Thomas Mueller Jan 2011

Super-Adiabatic Combustion In Porous Media With Catalytic Enhancement For Thermoelectric Power Conversion, Kyle Thomas Mueller

Electronic Theses and Dissertations

The combustion of ultra-lean fuel to air mixtures provides an efficient way to convert the chemical energy of hydrocarbons into useful power. Conventional burning techniques of a mixture have defined flammability limits beyond which a flame cannot self-propagate due to heat losses. Matrix stabilized porous medium combustion is an advanced technique in which a solid porous matrix within the combustion chamber accumulates heat from the hot gaseous products and preheats incoming reactants. This heat recirculation extends the standard flammability limits and allows the burning of ultra-lean fuel mixtures, conserving energy resources, or the burning of gases of low calorific value, …


A Novel Experimental Approach Using A Reconfigurable Test Setup For Complex Nonlinear Dynamic Systems, Aaron Rank Jan 2011

A Novel Experimental Approach Using A Reconfigurable Test Setup For Complex Nonlinear Dynamic Systems, Aaron Rank

Electronic Theses and Dissertations

Experimental nonlinear dynamics is an important area of study in the modern engineering field, with engineering applications in structural dynamics, structural control, and structural health monitoring. As a result, the discipline has experienced a great influx of research efforts to develop a versatile and reliable experimental methodology. A technical challenge in many experimental studies is the procurement of a device that exhibits the desired nonlinear behavior. As a result, many researchers have longed for a versatile, but accurate, testing methodology that has complete freedom to simulate a wide range of nonlinearities and stochastic behaviors. The objective of this study is …