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Articles 2911 - 2940 of 4180
Full-Text Articles in Engineering
Computationally Efficient Digital Backward Propagation For Fiber Nonlinearity Compensation, Likai Zhu
Computationally Efficient Digital Backward Propagation For Fiber Nonlinearity Compensation, Likai Zhu
Electronic Theses and Dissertations
The next generation fiber transmission system is limited by fiber nonlinearity. A distributed nonlinearity compensation method, known as Digital Backward Propagation (DBP), is necessary for effective compensation of the joint effect of dispersion and nonlinearity. However, in order for DBP to be accurate, a large number of steps are usually required for long-haul transmission, resulting in a heavy computational load. In real time DBP implementation, the FIR filters can be used for dispersion compensation and account for most of the computation per step. A method of designing a complementary filter pair is proposed. The individual errors in the frequency response …
Design And Optimization Of A Wave Energy Harvester Utilizing A Flywheel Energy Storage System, Steven Alexander Helkin
Design And Optimization Of A Wave Energy Harvester Utilizing A Flywheel Energy Storage System, Steven Alexander Helkin
Electronic Theses and Dissertations
This thesis details the design and optimization of a buoy used to collect renewable energy from ocean waves. The proposed buoy is a point absorber—a device that transforms the kinetic energy of the vertical motion of surface waves into electrical energy. The focus of the research is on the mechanical system used to collect the energy, and methods to improve it for eventual use in an actual wave energy harvester. A flywheel energy storage system was utilized in order to provide an improved power output from the system, even with the intermittent input of force exerted by ocean waves. A …
Evaluation And Modeling Of The Safety Of Open Road Tolling System, Muamer Ali Abuzwidah
Evaluation And Modeling Of The Safety Of Open Road Tolling System, Muamer Ali Abuzwidah
Electronic Theses and Dissertations
The goal of this thesis is to examine the traffic safety impact of upgrading Toll Plazas (TP) to Open Road Tolling (ORT). The ORT could enhance safety but could also pose some traffic safety concerns at Toll plazas. Crashes from eight years were investigated by evaluating the crash data before and after the implementation of the ORT. The study was conducted by using two approaches: 1) a simple before and after study and with a comparison group; 2) a modeling effort to help understand the relationship between the crash frequency and several important factors and circumstances such as injury severity, …
Homologous Pairing Through Dna Driven Harmonics-- A Simulation Investigation, Richard J. Calloway
Homologous Pairing Through Dna Driven Harmonics-- A Simulation Investigation, Richard J. Calloway
Electronic Theses and Dissertations
The objective of this research is to determine if a better understanding of the “molecule of life”, deoxyribonucleic acid or DNA can be obtained through Molecular Dynamics (MD) modeling and simulation (M&S) using contemporary MD M&S. It is difficult to overstate the significance of the DNA molecule. The now-completed Human Genome Project stands out as the most significant testimony yet to the importance of understanding DNA. The Human Genome Project (HGP) enumerated many areas of application of genomic research including molecular medicine, energy sources, environmental applications, agriculture and livestock breeding to name just a few. (Science, 2008) In addition to …
Wirelessly Sensing Resonate Frequency Of Passive Resonators With Different Q Values, Mathew Walter Lukacs
Wirelessly Sensing Resonate Frequency Of Passive Resonators With Different Q Values, Mathew Walter Lukacs
Electronic Theses and Dissertations
Numerous techniques exist for measuring temperature using passive devices such as SAW filters. However, SAW filters have a significant limitation regarding high temperature environments exceeding 1000⁰C [1]. There are several applications for a high temperature sensor in this range, most notably heat flux or temperature in turbine engines. For these environments, an alternative to SAW filters is to use a passive resonator. The resonate frequency will vary depending on the environment temperature. Understanding how the frequency changes with temperature will allow us to determine the environmental temperature. In order for this approach to work, it is necessary to induce resonance …
A Radar Interrogator For Wireless Passive Temperature Sensing, Jeffrey Charles Lambert
A Radar Interrogator For Wireless Passive Temperature Sensing, Jeffrey Charles Lambert
Electronic Theses and Dissertations
In this thesis I explore radio detection and ranging (RADAR) and software defined radio (SDR) in the context of wireless passive sensor interrogation. A RADAR topology is selected based upon preliminary measurements using ordinary laboratory instrumentation and then used for construction of a prototype X-band wireless measurement system using commercial, off-theshelf (COTS) components. This research explores the feasibility of wireless passive sensor interrogation through practical application of SDR and RADAR techniques to the interrogation of a wireless passive resonator signal. This work serves as a foundation for further research on sensor interrogation through establishment of critical system parameters in the …
The Effect Of Static Pressure On The Inertial Cavitation Threshold And Collapse Strength, Kenneth Bryan Bader
The Effect Of Static Pressure On The Inertial Cavitation Threshold And Collapse Strength, Kenneth Bryan Bader
Electronic Theses and Dissertations
The amplitude of the acoustic pressure required to nucleate a gas and/or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The hydrostatic dependence of the inertial cavitation threshold was measured up to 30 MPa in ultrapure water using a high quality factor spherical resonator. The threshold increased linearly with the hydrostatic pressure and was found to be temperature dependent. The strength of the bubble collapse at the threshold was measured in terms of shock waves and light emissions. The shock amplitudes increased linearly with the hydrostatic pressure, while …
Effects Of Thermo-Mechanical Loading From In-Situ Studies Of Eb-Pvd Thermal Barrier Coatings, Melan N. Jansz
Effects Of Thermo-Mechanical Loading From In-Situ Studies Of Eb-Pvd Thermal Barrier Coatings, Melan N. Jansz
Electronic Theses and Dissertations
The thermo-mechanical effects on the strain evolution within an EB-PVD thermal barrier coating (TBC) is presented in this work using in-situ characterization. Synchrotron X-ray diffraction at sector 1-ID at the Argonne National Laboratory provided both qualitative and quantitative in-situ data on the strain evolution under a thermal cycle with mechanical loading. The results show that at a critical combination of temperature and load, the stress in the thermally grown oxide (TGO) layer in the TBC reaches a tensile region. These significant findings enhance existing literature showing purely compressive strains within the TGO where mechanical loads have been neglected. The results …
Designing A Membrane Module For Determining The Permeance Of High Fluxing Membranes And The Testing Rtil-Membranes For Dehumidification., Sikyun Bae
Electronic Theses and Dissertations
Membrane-based gas dehumidification can have technical energy, and economical advantages over other dehumidification technologies. Because, it is simple to install, ease to operate, and take low process cost. Removal of water vapor from gases constitutes a significant expenditure of energy in our society. Dehydration via a membrane process would constitute wide spread energy savings. This thesis explores experimental issues involved with testing Room Temperature Ionic Liquid(RTIL)-membrane for dehumidifying gases. RTIL-membranes or Supported Ionic Liquid Membranes (SILMs) have advantageous performance for the separations of the gas pair CO2/CH4 and CO2/N2. Previous research did not separate the membrane mass transport resistance the …
Experimental Damage Diagnosis Of A Model Three-Story Spatial Frame, Samantha Sabatino
Experimental Damage Diagnosis Of A Model Three-Story Spatial Frame, Samantha Sabatino
Electronic Theses and Dissertations
Structural damage can be induced by a variety of events from short-term abnormal stresses to long-term natural aging. Detection of changes in a structure's ability to withstand subsequent loads can aid decisions on safety, repair, rehabilitation, and demolition. Dynamic property shifts can show internal cracks and minor damage before propagation or failure occurs, but only if a proper indicator is selected. In order to evaluate potential damage indices, a three-story metal frame building was constructed. Using Star Modal software, dynamic structural properties were obtained from modal decomposition on experimental tap test responses. The natural frequencies and mode shapes of the …
Column Capacity Evaluation For Low-Rise Moment Frame Steel Buildings In Mississippi Subject To Wind And Seismic Hazards, Yihong Shi
Electronic Theses and Dissertations
For the design of steel frame structures, AISC outlines approaches of second-order analysis. In this study, two of these approaches are considered: Amplified First-Order Analysis Method and Direct Analysis Method. The methods were studied using SAP2000. Amplification of moments in a two-story plane frame subject to a wind load case is computed using both methods and shown to be of comparable magnitude for small deformations. ASCE/SEI 7 and IBC provisions were used to develop lateral design load conditions for the frames. In this study, a hypothetical building was assumed to be constructed in four different locations (Southaven, Batesville, Jackson and …
Pulmonary Particle Deposition In Relation To Age, Body Weight, And Species, Lisa M. Weber
Pulmonary Particle Deposition In Relation To Age, Body Weight, And Species, Lisa M. Weber
Electronic Theses and Dissertations
As a result of dissimilarity in lung morphometry and physiological conditions, therapeutic aerosol particles deposit differently in humans of various ages and body weights. These particles also deposit differently in non-human species that are often utilized in inhalation and dosing studies. The focus of this work is to determine the optimal particle size and deposition (traditional efficiency and volume-weighted) of therapeutic particles in humans of both genders ranging in age from 3 months old to 21 years old and three non-human species (B6C3F1 mouse, Long-Evans hooded rat, and Beagle dog). This study finds that in humans, both optimal …
Research In High Performance And Low Power Computer Systems For Data-Intensive Environment, Pengju Shang
Research In High Performance And Low Power Computer Systems For Data-Intensive Environment, Pengju Shang
Electronic Theses and Dissertations
According to the data affinity, DAFA re-organizes data to maximize the parallelism of the affinitive data, and also subjective to the overall load balance. This enables DAFA to realize the maximum number of map tasks with data-locality. Besides the system performance, power consumption is another important concern of current computer systems. In the U.S. alone, the energy used by servers which could be saved comes to 3.17 million tons of carbon dioxide, or 580,678 cars {Kar09}. However, the goals of high performance and low energy consumption are at odds with each other. An ideal power management strategy should be able …
Rule-Based Decision Support System For Sensor Deployment In Drinking Water Networks, Natthaphon Prapinpongsanone
Rule-Based Decision Support System For Sensor Deployment In Drinking Water Networks, Natthaphon Prapinpongsanone
Electronic Theses and Dissertations
Drinking water distribution systems are inherently vulnerable to malicious contaminant events with environmental health concerns such as total trihalomethanes (TTHMs), lead, and chlorine residual. In response to the needs for long-term monitoring, one of the most significant challenges currently facing the water industry is to investigate the sensor placement strategies with modern concepts of and approaches to risk management. This study develops a Rule-based Decision Support System (RBDSS) to generate sensor deployment strategies with no computational burden as we oftentimes encountered via large-scale optimization analyses. Three rules were derived to address the efficacy and efficiency characteristics and they include: 1) …
Improving Throughput And Predictability Of High-Volume Business Processes Through Embedded Modeling, Joseph S. Dekeyrel
Improving Throughput And Predictability Of High-Volume Business Processes Through Embedded Modeling, Joseph S. Dekeyrel
Electronic Theses and Dissertations
Being faster is good. Being predictable is better. A faithful model of a system, loaded to reflect the system's current state, can then be used to look into the future and predict performance. Building faithful models of processes with high degrees of uncertainty can be very challenging, especially where this uncertainty exists in terms of processing times, queuing behavior and re-work rates. Within the context of an electronic, multi-tiered workflow management system (WFMS) the author builds such a model to endogenously quote due dates. A WFMS that manages business objects can be recast as a flexible flow shop in which …
Investigation Of Reactively Sputtered Boron Carbon Nitride Thin Films, Vinit O. Todi
Investigation Of Reactively Sputtered Boron Carbon Nitride Thin Films, Vinit O. Todi
Electronic Theses and Dissertations
Research efforts have been focused in the development of hard and wear resistant coatings over the last few decades. These protective coatings find applications in the industry such as cutting tools, automobile and machine part etc. Various ceramic thin films like TiN, TiAlN, TiC, SiC and diamond-like carbon (DLC) are examples of the films used in above applications. However, increasing technological and industrial demands request thin films with more complicated and advanced properties. For this purpose, B-C-N ternary system which is based on carbon, boron and nitrogen which exhibit exceptional properties and attract much attention from mechanical, optical and electronic …
Exploiting Opponent Modeling For Learning In Multi-Agent Adversarial Games, Kennard R. Laviers
Exploiting Opponent Modeling For Learning In Multi-Agent Adversarial Games, Kennard R. Laviers
Electronic Theses and Dissertations
An issue with learning effective policies in multi-agent adversarial games is that the size of the search space can be prohibitively large when the actions of both teammates and opponents are considered simultaneously. Opponent modeling, predicting an opponent’s actions in advance of execution, is one approach for selecting actions in adversarial settings, but it is often performed in an ad hoc way. In this dissertation, we introduce several methods for using opponent modeling, in the form of predictions about the players’ physical movements, to learn team policies. To explore the problem of decision-making in multi-agent adversarial scenarios, we use our …
Virtual Router Approach For Wireless Ad Hoc Networks, Ai Hua Ho
Virtual Router Approach For Wireless Ad Hoc Networks, Ai Hua Ho
Electronic Theses and Dissertations
Wireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an MANET is a self-organizing multi-hop wireless network in which all nodes within a given geographical area participate in the routing and data forwarding process. Such networks are scalable and self-healing. …
Multiagent Learning Through Indirect Encoding, David B. D'Ambrosio
Multiagent Learning Through Indirect Encoding, David B. D'Ambrosio
Electronic Theses and Dissertations
Designing a system of multiple, heterogeneous agents that cooperate to achieve a common goal is a difficult task, but it is also a common real-world problem. Multiagent learning addresses this problem by training the team to cooperate through a learning algorithm. However, most traditional approaches treat multiagent learning as a combination of multiple single-agent learning problems. This perspective leads to many inefficiencies in learning such as the problem of reinvention, whereby fundamental skills and policies that all agents should possess must be rediscovered independently for each team member. For example, in soccer, all the players know how to pass and …
Passive Wireless Saw Sensors With New And Novel Reflector Structures Design And Applications, Nikolai Kozlovski
Passive Wireless Saw Sensors With New And Novel Reflector Structures Design And Applications, Nikolai Kozlovski
Electronic Theses and Dissertations
Surface acoustic wave (SAW) devices are a solution for today’s ever growing need for passive wireless sensors. Orthogonal frequency coding (OFC) together with time division multiplexing (TDM) provides a large number of codes and coding algorithms producing devices that have excellent collision properties. Novel SAW noise-like re- flector (NLR) structures with pulse position modulation (PPM) are shown to exhibit good auto- and cross-correlation, and anti-collision properties. Multi-track, multi-transducer approaches yield devices with adjustable input impedances and enhanced collision properties for OFC TDM SAW sensor devices. Each track-transducer is designed for optimum performance for loss, coding, and chip reflectivity. Experimental results …
Use Of Vegetative Mulch As Daily And Intermediate Landfill Cover, Assal Edwar Haddad
Use Of Vegetative Mulch As Daily And Intermediate Landfill Cover, Assal Edwar Haddad
Electronic Theses and Dissertations
Management of yard waste is a significant challenge in the US, where in 2008 13.2% of the 250 million tons of municipal solid waste (MSW) was reported to be yard waste. This study describes research conducted in the laboratory and field to examine the application of vegetative mulch as daily and intermediate landfill cover. Mulch was found to exhibit stronger physical properties than soil, leading to a more stable landfill slope. Compaction of mulch was found to be significantly greater than soil, potentially resulting in airspace recovery. Degradation of mulch produced a soil-like material; degradation resulted in lower physical strength …
Characterization Of The Nonlinear Refractive Index Of Carbon Disulfide Over An Extended Spectral And Temporal Range, Marcus Seidel
Characterization Of The Nonlinear Refractive Index Of Carbon Disulfide Over An Extended Spectral And Temporal Range, Marcus Seidel
Electronic Theses and Dissertations
The intensity dependent refractive index change of a medium is frequently described in terms of the product n₂ · I where n₂ is the nonlinear refractive index and I the light intensity. The nonlinear refractive index is often treated as constant which is a reasonable assumption if the light interacts only with bound electrons. In the case of carbon disulfide (CS₂) however, nuclear motions contribute to n₂. These motions occur on the sub picosecond time scale and thus become especially relevant for ultrashort laser pulses. The neat liquid CS₂ is studied because it exhibits a large nonlinear refractive index in …
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Low Noise And Low Repetition Rate Semiconductor-Based Mode-Locked Lasers, Dimitrios Mandridis
Electronic Theses and Dissertations
The topic of this dissertation is the development of low repetition rate and low noise semiconductor-based laser sources with a focus on linearly chirped pulse laser sources. In the past decade chirped optical pulses have found a plethora of applications such as photonic analogto-digital conversion, optical coherence tomography, laser ranging, etc. This dissertation analyzes the aforementioned applications of linearly chirped pulses and their technical requirements, as well as the performance of previously demonstrated chirped pulse laser sources. Moreover, the focus is shifted to a specific application of the linearly chirped pulses, timestretched photonic analog-to-digital conversion (TS ADC). The challenges of …
Towards Calibration Of Optical Flow Of Crowd Videos Using Observed Trajectories, Iman K. Elbadramany
Towards Calibration Of Optical Flow Of Crowd Videos Using Observed Trajectories, Iman K. Elbadramany
Electronic Theses and Dissertations
The need exists for finding a quantitative method for validating crowd simulations. One approach is to use optical flow of videos of real crowds to obtain velocities that can be used for comparison to simulations. Optical flow, in turn, needs to be calibrated to be useful. It is essential to show that optical flow velocities obtained from crowd videos can be mapped into the spatially averaged velocities of the observed trajectories of crowd members, and to quantify the extent of the correlation of the results. This research investigates methods to uncover the best conditions for a good correlation between optical …
Design, Fabrication, And Testing Of High-Transparency Deep Ultra-Violet Contacts Using Surface Plasmon Coupling In Subwavelength Aluminum Meshes, Clarisse Mazuir
Design, Fabrication, And Testing Of High-Transparency Deep Ultra-Violet Contacts Using Surface Plasmon Coupling In Subwavelength Aluminum Meshes, Clarisse Mazuir
Electronic Theses and Dissertations
The present work aims at enhancing the external quantum efficiencies of ultra-violet (UV) sensitive photodetectors (PDs) and light emitting diodes (LEDs)for any light polarization. Deep UV solid state devices are made out of AlGaN or MgZnO and their performances suffer from the high resistivity of their p-doped regions. They require transparent p-contacts; yet the most commonly used transparent contacts have low transmission in the UV: indium tin oxide (ITO) and nickel-gold (Ni/Au 5/5 nms) transmit less than 50% and 30% respectively at 300 nm. Here we investigate the use of surface plasmons (SPs) to design transparent p-contacts for AlGaN devices …
Fatigue Testing And Computational Analysis Of A Spinal Implant, Timothy Helton
Fatigue Testing And Computational Analysis Of A Spinal Implant, Timothy Helton
Electronic Theses and Dissertations
The following study investigates the fatigue behavior of a spinal implant developed by Synthes, Inc. to provide stability and off load pressure from the discs in the lumbar region. The installation process for the StenoFix design utilizes plastic deformations to customize the device to each individual patient, but also has potential to degrade fatigue behavior. Physical testing of two titanium alloys, Ti-6Al-7Nb and Ti-15Mo, was conducted on hydraulic test frames and compared to computational simulations which were carried out for the following scenarios: cyclic excitation following plastic deformation; variation of material property definition; variation of loading location; and three modifications …
Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath
Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath
Electronic Theses and Dissertations
Quantum dots are semiconductive particles whose properties are highly influenced by the presence of at least one electron. Cadmium selenide quantum dots were synthesized via colloidal synthesis. Contrary to previous preparations, more focus was placed on the temperature rather than the duration of time at which they form. A series of colored solutions were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra showed that the temperature-dependent quantum dots were successfully synthesized. The quantum dots were also immobilized on various surfaces, and the luminescence properties were examined. The quantum dots that were …
High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke
High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke
Electronic Theses and Dissertations
The scope of this thesis was to develop a prototype high-impedance arc detection system that a utility worker could use as an early warning system while working in a manhole environment. As part of this system sensors and algorithms were developed to increase the sensitivity of detecting an arc while ignoring loads that can give false positive signatures for arcing. The latest technology was used to repeat measurements performed in previous research from decades ago that lacked in sampling speed and amplitude resolution. Several types of arcs were produced and analyzed so to establish a library of various waveform and …
New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps
New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps
Electronic Theses and Dissertations
The power distribution infrastructure in the United States is deteriorating at a rapid rate exposing infrastructure wiring and creating potential shock hazards. Periodic road and sidewalk maintenance projects can also expose wiring and create energized objects. In urban settings inadvertently energized objects include: lamp posts, bus shelters, metal street curbs, sign posts, transformer vaults, and manhole covers as well as concrete and asphalt pavement. Every year electric shocks occur when people and domestic animals (such as dogs and cats) make incidental contact with these energized objects. In very rare cases the shocks from these contacts are lethal. Through current personal …
Reconode: Towards An Autonomous Multi-Robot Team Agent For Usar, Kang Li
Reconode: Towards An Autonomous Multi-Robot Team Agent For Usar, Kang Li
Electronic Theses and Dissertations
Urban search and rescue (USAR) robots can benefit from small size as it facilitates movement in cramped quarters. Yet, small size limits actuator power, sensor payloads, computational capacity and battery life. We are alleviating these issues by developing the hardware and software infrastructure for high performance, heterogeneous, dynamically-reconfigurable miniature USAR robots, as well as a host of other relevant applications. In this thesis, a generic modular embedded system architecture based on the RecoNode multiprocessor is proposed, which consists of a set of hardware and software modules that can be configured to construct various types of robot systems for dynamic and …