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Articles 2041 - 2070 of 4180
Full-Text Articles in Engineering
Design Disjunction For Resilient Reconfigurable Hardware, Ahmad Alzahrani
Design Disjunction For Resilient Reconfigurable Hardware, Ahmad Alzahrani
Electronic Theses and Dissertations
Contemporary reconfigurable hardware devices have the capability to achieve high performance, power efficiency, and adaptability required to meet a wide range of design goals. With scaling challenges facing current complementary metal oxide semiconductor (CMOS), new concepts and methodologies supporting efficient adaptation to handle reliability issues are becoming increasingly prominent. Reconfigurable hardware and their ability to realize self-organization features are expected to play a key role in designing future dependable hardware architectures. However, the exponential increase in density and complexity of current commercial SRAM-based field-programmable gate arrays (FPGAs) has escalated the overhead associated with dynamic runtime design adaptation. Traditionally, static modular …
Liquid Crystal-Based Biosensors For The Detection Of Bile Acids, Sihui He
Liquid Crystal-Based Biosensors For The Detection Of Bile Acids, Sihui He
Electronic Theses and Dissertations
Bile acids are physiologically important metabolites, which are synthesized in liver as the end products of cholesterol metabolism and then secreted into intestine. They are amphiphilic molecules which play a critical role in the digestion and absorption of fats and fat-soluble vitamins through emulsification. The concentration of bile acids is an indicator for liver function. Individual suffering from liver diseases has a sharp increase in bile acid concentrations. Hence, the concentration level of bile acids has long been used as a biomarker for the early diagnosis of intestinal and liver diseases. Conventional methods of bile acid detection such as chromatography-mass …
Nonlinear Optical Response Of Simple Molecules And Two-Photon Semiconductor Lasers, Matthew Reichert
Nonlinear Optical Response Of Simple Molecules And Two-Photon Semiconductor Lasers, Matthew Reichert
Electronic Theses and Dissertations
This dissertation investigates two long standing issues in nonlinear optics: complete characterization of the ultrafast dynamics of simple molecules, and the potential of a two-photon laser using a bulk semiconductor gain medium. Within the Born-Oppenheimer approximation, nonlinear refraction in molecular liquids and gases can arise from both bound-electronic and nuclear origins. Knowledge of the magnitudes, temporal dynamics, polarization and spectral dependences of each of these mechanisms is important for many applications including filamentation, white-light continuum generation, all-optical switching, and nonlinear spectroscopy. In this work the nonlinear dynamics of molecules are investigated in both liquid and gas phase with the recently …
Optical Fibers For Space-Division Multiplexed Transmission And Networking, Cen Xia
Optical Fibers For Space-Division Multiplexed Transmission And Networking, Cen Xia
Electronic Theses and Dissertations
Single-mode fiber transmission can no longer satisfy exponentially growing capacity demand. Space-division multiplexing (SDM) appears to be the only way able to dramatically improve the transmission capacity, for which, novel optical fiber is one of the key technologies. Such fibers must possess the following characteristics: 1) high mode density per cross-sectional area and 2) low crosstalk or low modal differential group delay (DMGD) to reduce complexity of digital signal processing. In this dissertation, we explore the design and characterization of three kinds of fibers for SDM: few-mode fiber (FMF), few-mode multi-core fiber (FM-MCF) and coupled multi-core fiber (CMCF) as well …
Implementation Of A Raptorq-Based Protocol For Peer To Peer Network, Yuzhu Bai
Implementation Of A Raptorq-Based Protocol For Peer To Peer Network, Yuzhu Bai
Electronic Theses and Dissertations
The object of this thesis is to develop and test a Ruby based implementation of the RaptorQP2P protocol. The RaptorQP2P protocol is a novel peer-to-peer protocol based on RaptorQ forward error correction. This protocol facilitates delivery of a single file to a large number of peers. It applies two levels of RaptorQ encoding to the source file before packet transmission. Download completion time using RaptorQP2P was found to be significantly improved comparing to BitTorrent. We developed a Ruby interface to the Qualcomm proprietary RaptorQ software development kit library. Then we achieved the two levels of RaptorQ encoding and decoding with …
Mcmc- Based Optimization And Application, Xiaobin Wu
Mcmc- Based Optimization And Application, Xiaobin Wu
Electronic Theses and Dissertations
In the thesis, we study the theory of Markov Chain Monte Carlo (MCMC) and its application in statistical optimization. The MCMC method is a class of evolutionary algorithms for generating samples from given probability distributions. In the thesis, we first focus on the methods of slice sampling and simulated annealing. While slice sampling has a merit to generate samples based on the underlying distribution with adjustable step size, simulated annealing can facilitate samples to jump out of local optima and converge quickly to the global optimum. With this MCMC method, we then solve two practical optimization problems. The first problem …
The Neuromuscular Response To Spinal Manipulation: Quantifying The Effect Of Pain With Electromyography, Stuart James Currie
The Neuromuscular Response To Spinal Manipulation: Quantifying The Effect Of Pain With Electromyography, Stuart James Currie
Electronic Theses and Dissertations
Objective
To establish a methodology to quantify the neuromuscular response to spinal manipulation, develop a comprehensive date set including factors that affect the response, and compare the responses in both healthy participants and participants with acute and chronic low back pain.
Methods
Surface and indwelling electromyography at eight muscle locations were recorded during lumbar side-lying manipulations in 20 asymptomatic participants, 20 acute pain participants, and 20 chronic pain participants. Onset delay detection was optimized for signal detection failures and methodological comparisons were performed using a generalized linear model. The number of muscle responses and muscle activity onset delays in relation …
A New Methodology For Evaluating The Effectiveness Of Bus Rapid Transit Strategies, Ahmad Alomari
A New Methodology For Evaluating The Effectiveness Of Bus Rapid Transit Strategies, Ahmad Alomari
Electronic Theses and Dissertations
Over the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like these, innovative solutions, such as bus rapid transit (BRT), can provide an increased level of service without having to resort to other, …
The Experience Of Physical And Social Presence In A Virtual Learning Environment As Impacted By The Affordance Of Movement Enabled By Motion Tracking, Aleshia Hayes
Electronic Theses and Dissertations
This research synthesizes existing research findings that social presence (sense of connection with others) and physical presence (sense of being there) increase learning outcomes in Virtual Learning Environments (VLEs) with findings that traditional motion tracking of participants wearing head mounted displays in virtual reality increases both physical and social presence. This information suggests that motion tracking in mixed reality VLEs has a positive impact on social presence and on physical presence. For this study, the affordance of free movement among virtual objects is enabled by Microsoft Kinect tracking of the user's position that is translated to movement of the virtual …
Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger
Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger
Electronic Theses and Dissertations
Absorption plays a critical role in a variety of optical applications – sometimes it is desirable to minimize it as in optical fibers and waveguides, or to enhance it as in solar cells and photodetectors. We describe here a new optical scheme that controllably produces high optical absorption over a broad wavelength range (hundreds of nm) in systems that have low intrinsic absorption over the same range. This effect, 'coherent perfect absorption' or CPA, arises from a subtle interplay between interference and absorption of two beams incident on a weakly absorbing medium. In the first part of this study, we …
Planar Laser Induced Fluorescence Experiments And Modeling Study Of Jets In Crossflow At Various Injection Angles, Luke Thompson
Planar Laser Induced Fluorescence Experiments And Modeling Study Of Jets In Crossflow At Various Injection Angles, Luke Thompson
Electronic Theses and Dissertations
Planar Laser Induced Fluorescence (PLIF) with acetone seeding was applied to measure the scalar fields of an axisymmetric freejet and an inclined jet-in-crossflow as applicable to film cooling. From the scalar fields, jet-mixing and trajectory characteristics were obtained. In order to validate the technique, the canonical example of a nonreacting freejet of Reynolds Numbers 900-9000 was investigated. Desired structural characteristics were observed and showed strong agreement with computational modeling. After validating the technique with the axisymmetric jet, the jet-in-crossflow was tested with various velocity ratios and jet injection angles. Results indicated the degree of wall separation for different injection angles …
The Relationship Between Dna's Physical Properties And The Dna Molecule's Harmonic Signature, And Related Motion In Water--A Computational Investigation, Victor Boyer
Electronic Theses and Dissertations
This research investigates through computational methods whether the physical properties of DNA contribute to its harmonic signature, the uniqueness of that signature if present, and motion of the DNA molecule in water. When DNA is solvated in water at normal 'room temperature', it experiences a natural vibration due to the Brownian motion of the particles in the water colliding with the DNA. The null hypothesis is that there is no evidence to suggest a relationship between DNA's motion and strand length, while the alternative hypothesis is that there is evidence to suggest a relationship between DNA's vibrational motion and strand …
Integrated Sustainability Assessment Framework For The U.S. Transportation, Nuri Onat
Integrated Sustainability Assessment Framework For The U.S. Transportation, Nuri Onat
Electronic Theses and Dissertations
This dissertation aims to investigate the sustainability impacts of alternative vehicle technologies and develop comprehensive sustainability assessment frameworks to analyze potential impacts of these vehicles in the U.S. In order to assess sustainability impact of vehicle alternatives, life-cycle based models has been extensively used in the literature. Although life cycle-based models are often used for environmental impacts of alternative vehicles, analysis of social and economic impacts of these vehicles has gained a tremendous interest. In this regard, there is a growing interest among the international platform and academia to use the Life Cycle Sustainability Assessment framework to have more informed …
Traffic Conflict Analysis Under Fog Conditions Using Computer Simulation, Binya Zhang
Traffic Conflict Analysis Under Fog Conditions Using Computer Simulation, Binya Zhang
Electronic Theses and Dissertations
The weather condition is a crucial influence factor on road safety issues. Fog is one of the most noticeable weather conditions, which has a significant impact on traffic safety. Such condition reduces the road's visibility and consequently can affect drivers' vision, perception, and judgments. The statistical data shows that many crashes are directly or indirectly caused by the low-visibility weather condition. Hence, it is necessary for road traffic engineers to study the relationship of road traffic accidents and their influence factors. Among these factors, the traffic volume and the speed limits in poor visibility areas are the primary reasons that …
Analysis Of Steady State Micro-Droplet Evaporation To Enhance Heat Dissipation From Tiny Surfaces., Harish Voota
Analysis Of Steady State Micro-Droplet Evaporation To Enhance Heat Dissipation From Tiny Surfaces., Harish Voota
Electronic Theses and Dissertations
Experimental investigations and numerical predictions of steady state microdroplet evaporation experiments are presented. Steady state droplet evaporation experiments are conducted to understand (1) Droplet contact line influence on evaporation rate efficiency, (2) Droplet contact angle correlation to evaporation rate and (3) Substrate cooling. Experiments are performed on a polymer substrate with a moat like trench (laser patterned) to control droplet contact line dynamics. A bottom-up methodology is implemented for droplet formation on the patterned substrate. Droplet evaporation rates on substrate temperatures 22°C≤ ∆TSubstrate ≤75°C and contact angles 80°≤ Θ ≤110° are measured. For a pinned microdroplet (CCR), volumetric infuse rate …
Parallel Distributed Discrete Event Simulation Optimization Using Complexity And Deep Learning, Edwin Cortes
Parallel Distributed Discrete Event Simulation Optimization Using Complexity And Deep Learning, Edwin Cortes
Electronic Theses and Dissertations
Parallel distributed discrete event simulation (PDDES) is the execution of a discrete event simulation on a tightly or loosely coupled computer system with multiple processors. The discrete-event simulation model is decomposed into several logical processors (LPs) or simulation objects that can be executed concurrently using partitioning types such as spatial and temporal. PDDES is exceedingly important for the reduction of the simulation time, increase of model size, intellectual property issue mitigation in multi-enterprise simulations, and the sharing of resources. One of the problems with PDDES is the time management to provide flow control over event processing, the process flow, and …
An Investigation Of Physiological Measures In A Marketing Decision Task, Nelson Lerma
An Investigation Of Physiological Measures In A Marketing Decision Task, Nelson Lerma
Electronic Theses and Dissertations
The objective of the present study was to understand the use of physiological measures as an alternative to traditional market research tools, such as self-reporting measures and focus groups. For centuries, corporations and researchers have relied almost exclusively on traditional measures to gain insights into consumer behavior. Oftentimes, traditional methods have failed to accurately predict consumer demand, and this has prompted corporations to explore alternative methods that will accurately forecast future sales. One the most promising alternative methods currently being investigated is the use of physiological measures as an indication of consumer preference. This field, also referred to as neuromarketing, …
Response Of Streamflow And Sediment Loading In The Apalachicola River, Florida To Climate And Land Use Land Cover Change, Paige Hovenga
Response Of Streamflow And Sediment Loading In The Apalachicola River, Florida To Climate And Land Use Land Cover Change, Paige Hovenga
Electronic Theses and Dissertations
Located in Florida's panhandle, the Apalachicola River is the southernmost reach of the Apalachicola-Chattahoochee-Flint (ACF) River basin. Streamflow and sediment drains to Apalachicola Bay in the Northern Gulf of Mexico, directly influencing the ecology of the region, in particular seagrass and oyster production. The objective of this study is to evaluate the response of runoff and sediment loading in the Apalachicola River under projected climate change scenarios and land use / land cover (LULC) change. A hydrologic model using the Soil Water Assessment Tool (SWAT) was developed for the Apalachicola region to simulate daily discharge and sediment load under present …
Effect Of Ph And Temperature On Halogenated Dbps, Sm Shamimur Rahman
Effect Of Ph And Temperature On Halogenated Dbps, Sm Shamimur Rahman
Electronic Theses and Dissertations
Water scarcity is one of the most challenging issues in the world in the 21st century. It is estimated that there are more than one billion of people without adequate access to freshwater and facing water shortages and water deficits. People are forced to drink polluted water despite the risk of consuming pathogenic microorganisms in the water that transmit waterborne diseases such as bacterial infections, protozoal infections and viral infections. The water disinfection process is one of the most important environmental technological advances in the 20th century which inactivates microbial contaminants in drinking water. Disinfection byproducts (DBPs) are a group …
High Efficiency And Wide Color Gamut Liquid Crystal Displays, Zhenyue Luo
High Efficiency And Wide Color Gamut Liquid Crystal Displays, Zhenyue Luo
Electronic Theses and Dissertations
Liquid crystal display (LCD) has become ubiquitous and indispensable in our daily life. Recently, it faces strong competition from organic light emitting diode (OLED). In order to maintain a strong leader position, LCD camp has an urgent need to enrich the color performance and reduce the power consumption. This dissertation focuses on solving these two emerging and important challenges. In the first part of the dissertation we investigate the quantum dot (QD) technology to improve the both the color gamut and the light efficiency of LCD. QD emits saturated color and grants LCD the capability to reproduce color vivid images. …
Entanglement And Coherence In Classical And Quantum Optics, Kumel Kagalwala
Entanglement And Coherence In Classical And Quantum Optics, Kumel Kagalwala
Electronic Theses and Dissertations
We explore the concepts of coherence and entanglement as they apply to both the classical and quantum natures of light. In the classical domain, we take inspiration from the tools and concepts developed in foundational quantum mechanics and quantum information science to gain a better understanding of classical coherence theory of light with multiple degrees of freedom (DoFs). First, we use polarization and spatial parity DoFs to demonstrate the notion of classical entanglement, and show that Bell's measure can serve as a useful tool in distinguishing between classical optical coherence theory. Second, we establish a methodical yet versatile approach called …
Autonomous Quadcopter Videographer, Quiquia Rey Coaguila
Autonomous Quadcopter Videographer, Quiquia Rey Coaguila
Electronic Theses and Dissertations
In recent years, the interest in quadcopters as a robotics platform for autonomous photography has increased. This is due to their small size and mobility, which allow them to reach places that are difficult or even impossible for humans. This thesis focuses on the design of an autonomous quadcopter videographer, i.e. a quadcopter capable of capturing good footage of a specific subject. In order to obtain this footage, the system needs to choose appropriate vantage points and control the quadcopter. Skilled human videographers can easily spot good filming locations where the subject and its actions can be seen clearly in …
Modeling User Transportation Patterns Using Mobile Devices, Erfan Davami
Modeling User Transportation Patterns Using Mobile Devices, Erfan Davami
Electronic Theses and Dissertations
Participatory sensing frameworks use humans and their computing devices as a large mobile sensing network. Dramatic accessibility and affordability have turned mobile devices (smartphone and tablet computers) into the most popular computational machines in the world, exceeding laptops. By the end of 2013, more than 1.5 billion people on earth will have a smartphone. Increased coverage and higher speeds of cellular networks have given these devices the power to constantly stream large amounts of data. Most mobile devices are equipped with advanced sensors such as GPS, cameras, and microphones. This expansion of smartphone numbers and power has created a sensing …
Atmospheric Pressure Chemical Vapor Deposition Of Functional Oxide Materials For Crystalline Silicon Solar Cells, Kristopher Davis
Atmospheric Pressure Chemical Vapor Deposition Of Functional Oxide Materials For Crystalline Silicon Solar Cells, Kristopher Davis
Electronic Theses and Dissertations
Functional oxides are versatile materials that can simultaneously enable efficiency gains and cost reductions in crystalline silicon (c-Si) solar cells. In this work, the deposition of functional oxide materials using atmospheric pressure chemical vapor deposition (APCVD) and the integration of these materials into c-Si solar cells are explored. Specifically, thin oxide films and multi-layer film stacks are utilized for the following purposes: (1) to minimize front surface reflectance without increasing parasitic absorption within the anti-reflection coating(s); (2) to maximize internal back reflectance of rear passivated cells, thereby increasing optical absorption of weakly absorbed long wavelength photons (? > 900 nm); (3) …
Assessing Biofiltration Pretreatment For Ultrafiltration Membrane Processes, Andrea Cumming
Assessing Biofiltration Pretreatment For Ultrafiltration Membrane Processes, Andrea Cumming
Electronic Theses and Dissertations
An engineered biological filtration (biofiltration) process treating a nutrient-enriched, low-alkalinity, organic-laden surface water downstream of conventional coagulation-clarification and upstream of an ultrafiltration (UF) membrane process was assessed for its treatment effectiveness. The impact of biofiltration pretreatment on UF membrane performance was evaluated holistically by investigating the native source water chemistry and extending the analysis into the drinking water distribution system. The biofiltration process was also compared in treatment performance to two alternative pretreatment technologies, including magnetic ion exchange (MIEX®) and granular activated carbon (GAC) adsorption. The MIEX®, GAC adsorption, and biologically active carbon (BAC) filtration pretreatments were integrated with conventional …
Modeling And Analysis Of Automated Storage And Retrievals System With Multiple In-The-Aisle Pick Positions, Faraz Ramtin
Modeling And Analysis Of Automated Storage And Retrievals System With Multiple In-The-Aisle Pick Positions, Faraz Ramtin
Electronic Theses and Dissertations
This dissertation focuses on developing analytical models for automated storage and retrieval system with multiple in-the-aisle pick positions (MIAPP-AS/RS). Specifically, our first contribution develops an expected travel time model for different pick positions and different physical configurations for a random storage policy. This contribution has been accepted for publication in IIE Transactions (Ramtin & Pazour, 2014) and was the featured article in the IE Magazine (Askin & Nussbaum, 2014). The second contribution addresses an important design question associated with MIAPP-AS/RS, which is the assignment of items to pick positions in an MIAPP-AS/RS. This contribution has been accepted for publication in …
White Light Continuum For Broadband Nonlinear Spectroscopy, Trenton Ensley
White Light Continuum For Broadband Nonlinear Spectroscopy, Trenton Ensley
Electronic Theses and Dissertations
Supercontinuum (SC) generation, oftentimes referred to as white-light continuum (WLC), has been a subject of interest for more than 40 years. From the first observation of WLC in condensed media in the early 1970s to the first observation of WLC in gases in the mid-1980s, much work has been devoted to developing a framework for understanding the complex nature of this phenomenon as well as discovering its utility in various applications. The main effort of this dissertation is to develop a WLC for the purpose of broadband nonlinear spectroscopy and use it in spectroscopic measurements. The ability to generate a …
Two-Photon Absorption In Bulk Semiconductors And Quantum Well Structures And Its Applications, Himansu Pattanaik
Two-Photon Absorption In Bulk Semiconductors And Quantum Well Structures And Its Applications, Himansu Pattanaik
Electronic Theses and Dissertations
The purpose of this dissertation is to provide a study and possible applications of two-photon absorption (2PA), in direct-gap semiconductors and quantum-well (QW) semiconductor structures. One application uses extremely nondegenerate (END) 2PA, for mid-infrared (mid-IR) detection in uncooled semiconductors. The use of END, where the two photons have very different energies gives strong enhancement comapared to degenerate 2PA. This END-2PA enhanced detection is also applied to mid-IR imaging and light detection and ranging (LIDAR) in uncooled direct-gap photodiodes. A theoretical study of degenerate 2PA (D-2PA) in quantum wells, QWs, is presented, along with a new theory of ND 2PA in …
Conservation Laws And Electromagnetic Interactions, Veerachart Kajorndejnukul
Conservation Laws And Electromagnetic Interactions, Veerachart Kajorndejnukul
Electronic Theses and Dissertations
Aside from energy, light carries linear and angular momenta that can be transferred to matter. The interaction between light and matter is governed by conservation laws that can manifest themselves as mechanical effects acting on both matter and light waves. This interaction permits remote, precise, and noninvasive manipulation and sensing at microscopic levels. In this dissertation, we demonstrated for the first time a complete set of opto-mechanical effects that are based on nonconservative forces and act at the interface between dielectric media. Without structuring the light field, forward action is provided by the conventional radiation pressure while a backward movement …
Photon Statistics In Disordered Lattices, Hasan Kondakci
Photon Statistics In Disordered Lattices, Hasan Kondakci
Electronic Theses and Dissertations
Propagation of coherent waves through disordered media, whether optical, acoustic, or radio waves, results in a spatially redistributed random intensity pattern known as speckle -- a statistical phenomenon. The subject of this dissertation is the statistics of monochromatic coherent light traversing disordered photonic lattices and its dependence on the disorder class, the level of disorder and the excitation configuration at the input. Throughout the dissertation, two disorder classes are considered, namely, diagonal and off-diagonal disorders. The latter exhibits disorder-immune chiral symmetry -- the appearance of the eigenmodes in skew-symmetric pairs and the corresponding eigenvalues in opposite signs. When a disordered …