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Articles 121 - 150 of 155
Full-Text Articles in Engineering
Control Based Soft Switching Three-Phase Micro-Inverter: Efficiency And Power Density Optimization, Ahmadreza Amirahmadi
Control Based Soft Switching Three-Phase Micro-Inverter: Efficiency And Power Density Optimization, Ahmadreza Amirahmadi
Electronic Theses and Dissertations
In the field of renewable energy, solar photovoltaic is growing exponentially. Grid-tied PV micro-inverters have become the trend for future PV system development because of their remarkable advantages such as enhanced energy production due to MPPT implementation for each PV panel, high reliability due to redundant and distributed system architecture, and simple design, installation, and management due to its plug-and-play feature. Conventional approaches for the PV micro-inverters are mainly in the form of single-phase grid connected and they aim at the residential and commercial rooftop applications. It would be advantageous to extend the micro-inverter concept to large size PV installations …
Practical Implementations Of The Active Set Method For Support Vector Machine Training With Semi-Definite Kernels, Christopher Sentelle
Practical Implementations Of The Active Set Method For Support Vector Machine Training With Semi-Definite Kernels, Christopher Sentelle
Electronic Theses and Dissertations
The Support Vector Machine (SVM) is a popular binary classification model due to its superior generalization performance, relative ease-of-use, and applicability of kernel methods. SVM training entails solving an associated quadratic programming (QP) that presents significant challenges in terms of speed and memory constraints for very large datasets; therefore, research on numerical optimization techniques tailored to SVM training is vast. Slow training times are especially of concern when one considers that re-training is often necessary at several values of the models regularization parameter, C, as well as associated kernel parameters. The active set method is suitable for solving SVM problem …
Green Technologies And Sensor Networks For Bmp Evaluation In Stormwater Retention Ponds And Wetlands., Anthony Crawford
Green Technologies And Sensor Networks For Bmp Evaluation In Stormwater Retention Ponds And Wetlands., Anthony Crawford
Electronic Theses and Dissertations
The aim of this thesis is to examine and develop new techniques in stormwater Best Management Practices (BMP) for nutrient and erosion reduction and monitoring by incorporation of low impact green technologies and sensor networks. Previous research has found excessive nutrient loading of nitrogen and phosphorus species from urban stormwater runoff can lead to ecological degradation and eutrophication of receiving lakes and rivers (Fareed and Abid, 2005). In response, the Florida Department of Environmental Protection (FDEP) has set forth reduction goals as established in Total Maximum Daily Load (TMDL) reports to reduce nutrient loading and restore, or maintain, Florida water …
Mechanical And Thermal Characterization Of Continuous Fiber-Reinforced Pyrolysis-Derived Carbon-Matrix Composites, Donovan Lui
Mechanical And Thermal Characterization Of Continuous Fiber-Reinforced Pyrolysis-Derived Carbon-Matrix Composites, Donovan Lui
Electronic Theses and Dissertations
Maturity of high-temperature polymer-reinforced composites defer to conventionally expensive and intensive methods in both material and manufacturing aspects. Even traditional carbon-carbon, aerogel, and ceramic approaches are highly limited by difficult manufacturing techniques and are subject to sensitive handling throughout their processing and lifetime. Despite their utility in extreme environments, the high costs of existing high-temperature composites find limited practical applicability under high-performance applications. The development of continuous fiber-reinforced pyrolysis-derived carbon-matrix composites aim to circumvent the issues surrounding the manufacturing and handling of conventional high-temperature composites. Polymer matrix composites (PMCs) have a number of attractive properties including light weight, high stiffness-to-weight …
Assessing The Effectiveness Of Workload Measures In The Nuclear Domain, Joseph Mercado
Assessing The Effectiveness Of Workload Measures In The Nuclear Domain, Joseph Mercado
Electronic Theses and Dissertations
An operator's performance and mental workload when interacting with a complex system, such as the main control room (MCR) of a nuclear power plant (NPP), are major concerns when seeking to accomplish safe and successful operations. The impact of performance on operator workload is one of the most widely researched areas in human factors science with over five hundred workload articles published since the 1960s (Brannick, Salas, & Prince, 1997; Meshkati & Hancock, 2011). Researchers have used specific workload measures across domains to assess the effects of taskload. However, research has not sufficiently assessed the psychometric properties, such as reliability, …
Combustion Instability Mechanism Of A Reacting Jet In Cross Flow At Gas Turbine Operating Conditions, Jared Pent
Combustion Instability Mechanism Of A Reacting Jet In Cross Flow At Gas Turbine Operating Conditions, Jared Pent
Electronic Theses and Dissertations
Modern gas turbine designs often include lean premixed combustion for its emissions benefits; however, this type of combustion process is susceptible to self-excited combustion instabilities that can lead to damaging heat loads and system vibrations. This study focuses on identifying a mechanism of combustion instability of a reacting jet in cross flow, a flow feature that is widely used in the design of gas turbine combustion systems. Experimental results from a related study are used to validate and complement three numerical tools that are applied in this study – self-excited Large Eddy Simulations, 3D thermoacoustic modeling, and 1D instability modeling. …
Processing And Characterization Of Multifunctional Thermoplastic Nanocomposite Films, Xin Wang
Processing And Characterization Of Multifunctional Thermoplastic Nanocomposite Films, Xin Wang
Electronic Theses and Dissertations
Nanoparticles reinforced polymer composite films have been widely studied for their enhanced mechanical, electrical and thermal properties compared with host polymer matrix. However, most research was conducted on incorporation of nanoparticles in polymer films to improve single property and there is a lack of research on the multifunctional polymer nanocomposite films. In this work, a scalable and continuous spray deposition process was developed for the production of nanoparticles reinforced multifunctional thermoplastic nanocomposite films. This process is capable of making a thin sheet of thermoplastic nanocomposites with high nanoparticle loadings. The smallest thickness can be 40um. The objective of this study …
Response Of Electrified Micro-Jets To Electrohydrodynamic Perturbations, Weiwei Yang
Response Of Electrified Micro-Jets To Electrohydrodynamic Perturbations, Weiwei Yang
Electronic Theses and Dissertations
The breakup of liquid jets is ubiquitous with rich underpinning physics and widespread applications. The natural breakup of liquid jets originates from small ambient perturbations, which can grow exponentially until the amplitude as large as the jet radius is reached. For unelectrified inviscid jets, surface energy analysis shows that only the axisymmetric perturbation is possibly unstable, and this mode is referred as varicose instability. For electrified jets, the presence of surface charge enables additional unstable modes, among which the most common one is the whipping (or kink) instability that bends and stretches the charged jet that is responsible for the …
Rhenium, Osmium And Iridium Diborides By Mechanochemistry: Synthesis, Structure, Thermal Stability And Mechanical Properties, Zhilin Xie
Electronic Theses and Dissertations
Borides are implemented in a range of industrial applications due to their unique mechanical, electrical, thermal and catalytic properties. In particular, transition metal diborides are of special interest. In the recent years, borides of rhenium (Re), osmium (Os) and iridium (Ir) have been studied as for their ultra-hardness and superior stiffness. In this dissertation, a mechanochemical method is introduced to produce rhenium diboride (ReB2) powder, a novel hexagonal osmium diboride (h-OsB2), and iridium boride powders. Densification by Spark Plasma Sintering (SPS), thermal stability and mechanical properties of h-OsB2 were also studied. ReB2 was recently reported to exhibit high hardness and …
Human-Robot Interaction For Multi-Robot Systems, Bennie Lewis
Human-Robot Interaction For Multi-Robot Systems, Bennie Lewis
Electronic Theses and Dissertations
Designing an effective human-robot interaction paradigm is particularly important for complex tasks such as multi-robot manipulation that require the human and robot to work together in a tightly coupled fashion. Although increasing the number of robots can expand the area that the robots can cover within a bounded period of time, a poor human-robot interface will ultimately compromise the performance of the team of robots. However, introducing a human operator to the team of robots, does not automatically improve performance due to the difficulty of teleoperating mobile robots with manipulators. The human operator’s concentration is divided not only among multiple …
Multimaterial Fibers And Tapers A Platform For Nonlinear Photonics And Nanotechnology, Soroush Shabahang
Multimaterial Fibers And Tapers A Platform For Nonlinear Photonics And Nanotechnology, Soroush Shabahang
Electronic Theses and Dissertations
The development of optical sources and components suitable for the mid-infrared is crucial for applications in this spectral range to reach the maturity level of their counterparts in the visible and near-infrared spectral regimes. The recent commercialization of quantum cascade lasers is leading to further interest in this spectral range. Wideband mid-infrared coherent sources, such as supercontinuum generation, have yet to be fully developed. A mid-infrared supercontinuum source would allow for unique applications in spectroscopy and sensing. Over the last decade, it has been shown that high-index confinement in highly nonlinear fibers pumped with high-peak-power pulses is an excellent approach …
Sps: An Sms-Based Push Service For Energy Saving In Smartphone's Idle State, Erich Dondyk
Sps: An Sms-Based Push Service For Energy Saving In Smartphone's Idle State, Erich Dondyk
Electronic Theses and Dissertations
Despite of all the advances in smartphone technology in recent years, smartphones still remain limited by their battery life. Unlike other power hungry components in the smartphone, the cellular data and Wi-Fi interfaces often continue to be used even while the phone is in the idle state to accommodate unnecessary data traffic produced by some applications. In addition, bad reception has been proven to greatly increase energy consumed by the radio, which happens quite often when smartphone users are inside buildings. In this paper, we present a Short message service Push based Service (SPS) to save unnecessary power consumption when …
The Effects Of Bam As An Adsorptive Media On Phosphorus Removal In Stormwater, Sultan Salamah
The Effects Of Bam As An Adsorptive Media On Phosphorus Removal In Stormwater, Sultan Salamah
Electronic Theses and Dissertations
To maintain the quality of receiving water bodies, it is desirable to remove total phosphorus (TP) in stormwater runoff. Many media filtration technologies have been developed to achieve TP and soluble reactive phosphorus (SRP) removal. Efficient media adsorption is essential to insure control of stormwater phosphorus inputs to the receiving water body. This project develops and analyzes a functionalized Biosorption Media (BAM) to remove phosphorus species from stormwater runoff. One goal of this project is to find the BAM values for coefficients such as maximum adsorption capacity (QM: 4.35E-05) for the media through SRP isotherm equilibrium experiments using the Langmuir …
Performance Evaluation Of Two Silt Fence Geosynthetic Fabrics During And After Rainfall Event, Gregg Dubinsky
Performance Evaluation Of Two Silt Fence Geosynthetic Fabrics During And After Rainfall Event, Gregg Dubinsky
Electronic Theses and Dissertations
Silt fence is one of the most widely used perimeter control devices and is considered an industry standard for use in the control of sediment transport from construction sites. Numerous research studies have been conducted on the use of silt fence as a perimeter control, including a number of studies involving controlled laboratory flume tests and outdoor tests performed in the field on construction sites with actual monitored storm events. In field tests, due to the random and uncontrollable nature of real storm events and field conditions, studies have shown difficulty in evaluating silt fence performance. These field studies have …
Learning Collective Behavior In Multi-Relational Networks, Xi Wang
Learning Collective Behavior In Multi-Relational Networks, Xi Wang
Electronic Theses and Dissertations
With the rapid expansion of the Internet and WWW, the problem of analyzing social media data has received an increasing amount of attention in the past decade. The boom in social media platforms offers many possibilities to study human collective behavior and interactions on an unprecedented scale. In the past, much work has been done on the problem of learning from networked data with homogeneous topologies, where instances are explicitly or implicitly inter-connected by a single type of relationship. In contrast to traditional content-only classification methods, relational learning succeeds in improving classification performance by leveraging the correlation of the labels …
Semiconductor Laser Based On Thermoelectrophotonics, Xiaohang Liu
Semiconductor Laser Based On Thermoelectrophotonics, Xiaohang Liu
Electronic Theses and Dissertations
This dissertation presents to our knowledge the first demonstration of a quantum well (QW) laser monolithically integrated with internal optical pump based on a light emitting diode (LED). The LED with high efficiency is operated in a thermoelectrophotonic (TEP) regime for which it can absorb both its own emitted light and heat. The LED optical pump can reduce internal optical loss in the QW laser, and enables monolithically integrated TEP heat pumps to the semiconductor laser. The design, growth and fabrication processes of the laser chip are discussed, and its experimental data is presented. In order to further increase the …
Specialty Fiber Lasers And Novel Fiber Devices, Clemence Jollivet
Specialty Fiber Lasers And Novel Fiber Devices, Clemence Jollivet
Electronic Theses and Dissertations
At the Dawn of the 21st century, the field of specialty optical fibers experienced a scientific revolution with the introduction of the stack-and-draw technique, a multi-steps and advanced fiber fabrication method, which enabled the creation of well-controlled micro-structured designs. Since then, an extremely wide variety of finely tuned fiber structures have been demonstrated including novel materials and novel designs. As the complexity of the fiber design increased, highly-controlled fabrication processes became critical. To determine the ability of a novel fiber design to deliver light with properties tailored according to a specific application, several mode analysis techniques were reported, addressing the …
Load Transfer In An Isolated Particle Embedded Within An Epoxy Matrix, Erik Durnberg
Load Transfer In An Isolated Particle Embedded Within An Epoxy Matrix, Erik Durnberg
Electronic Theses and Dissertations
Particulate composites are widely used in many aerospace applications such as protective coatings, adhesives, or structural members of a body and their mechanical properties and behavior have gained increasing significance. The addition of modifiers such as alumina generally leads to improved mechanical properties. This addition also enables the non-invasive study of the load transfer between the particle and the matrix. Understanding the load transfer between the particulate and the matrix material is the first step to understanding the behavior and mechanical properties of the composite as a whole. In this work, samples with an isolated alumina particle embedded in an …
Visual Geo-Localization And Location-Aware Image Understanding, Amir Roshan Zamir
Visual Geo-Localization And Location-Aware Image Understanding, Amir Roshan Zamir
Electronic Theses and Dissertations
Geo-localization is the problem of discovering the location where an image or video was captured. Recently, large scale geo-localization methods which are devised for ground-level imagery and employ techniques similar to image matching have attracted much interest. In these methods, given a reference dataset composed of geo-tagged images, the problem is to estimate the geo-location of a query by finding its matching reference images. In this dissertation, we address three questions central to geo-spatial analysis of ground-level imagery: 1) How to geo-localize images and videos captured at unknown locations? 2) How to refine the geo-location of already geo-tagged data? 3) …
Pen-Based Methods For Recognition And Animation Of Handwritten Physics Solutions, Salman Cheema
Pen-Based Methods For Recognition And Animation Of Handwritten Physics Solutions, Salman Cheema
Electronic Theses and Dissertations
There has been considerable interest in constructing pen-based intelligent tutoring systems due to the natural interaction metaphor and low cognitive load afforded by pen-based interaction. We believe that pen-based intelligent tutoring systems can be further enhanced by integrating animation techniques. In this work, we explore methods for recognizing and animating sketched physics diagrams. Our methodologies enable an Intelligent Tutoring System (ITS) to understand the scenario and requirements posed by a given problem statement and to couple this knowledge with a computational model of the student's handwritten solution. These pieces of information are used to construct meaningful animations and feedback mechanisms …
Safety Effectiveness Of Conversion Of Two-Way-Left-Turn Lanes Into Raised Medians, Saif Alarifi
Safety Effectiveness Of Conversion Of Two-Way-Left-Turn Lanes Into Raised Medians, Saif Alarifi
Electronic Theses and Dissertations
Two way left turn lanes (TWLTL) and raised medians are common median treatments on roadways. This research focused on evaluating the safety effectiveness of conversion of TWLTLs into raised medians using Before-After and Cross Sectional Studies. In the Before-After Studies, we evaluated the effect of this treatment using the Naive, Before-After with Comparison Group (CG), and Before-After with Empirical Bayes (EB) Methods. In order to apply these methods, a total of 33 segments of a treated group and 109 segments of a comparison group have been collected. Also, safety performance functions (SPFs) have been developed using the negative binomial model …
Model-Based Systems Engineering Approach To Distributed And Hybrid Simulation Systems, John Pastrana
Model-Based Systems Engineering Approach To Distributed And Hybrid Simulation Systems, John Pastrana
Electronic Theses and Dissertations
INCOSE defines Model-Based Systems Engineering (MBSE) as "the formalized application of modeling to support system requirements, design, analysis, verification, and validation activities beginning in the conceptual design phase and continuing throughout development and later life cycle phases." One very important development is the utilization of MBSE to develop distributed and hybrid (discrete-continuous) simulation modeling systems. MBSE can help to describe the systems to be modeled and help make the right decisions and partitions to tame complexity. The ability to embrace conceptual modeling and interoperability techniques during systems specification and design presents a great advantage in distributed and hybrid simulation systems …
Modeling And Fault Detection In Dc Side Of Photovoltaic Arrays, Mohd Akram
Modeling And Fault Detection In Dc Side Of Photovoltaic Arrays, Mohd Akram
Electronic Theses and Dissertations
Fault detection in PV systems is a key factor in maintaining the integrity of any PV system. Faults in photovoltaic systems can cause irrevocable damages to the stability of the PV system and substantially decrease the power output generated from the array of PV modules. Among'st the various AC and DC faults in a PV system, the clearance of the AC side faults is achieved by conventional AC protection schemes,the DC side, however , there still exists certain faults which are difficult to detect and clear. This paper deals with the modeling, detection and classification of these types of DC …
Context-Aware Mobile Augmented Reality Visualization In Construction Engineering Education, Arezoo Shirazi
Context-Aware Mobile Augmented Reality Visualization In Construction Engineering Education, Arezoo Shirazi
Electronic Theses and Dissertations
Recent studies suggest that the number of students pursuing science, technology, engineering, and mathematics (STEM) degrees has been generally decreasing. An extensive body of research cites the lack of motivation and engagement in the learning process as a major underlying reason of this decline. It has been discussed that if properly implemented, instructional technology can enhance student engagement and the quality of learning. Therefore, the main goal of this research is to implement and assess effectiveness of augmented reality (AR)-based pedagogical tools on student learning. For this purpose, two sets of experiments were designed and implemented in two different construction …
An Introductory Study Of The Dynamics Of Autorotation For Wind Energy Harvesting, Bilal Salih
An Introductory Study Of The Dynamics Of Autorotation For Wind Energy Harvesting, Bilal Salih
Electronic Theses and Dissertations
Wind turbines have been used for decades to harvest wind energy. They are suitable only to work on close to ground, and have several drawbacks that are related to the availability of the wind and the amount of extracted power compared with the cost of construction. On the other hand, there is an abundant wind power that is available at high altitudes. The wind jet streams at high elevations 8 - 12 kms are pervasive and persistent, and can potentially produce immense wind energy. Even at moderate elevations of 4 - 5 kms, wind power densities are much higher than …
A Framework Of Critical Success Factors For Business Organizations That Lead To Performance Excellence Based On A Financial And Quality Systems Assessment., Melissa Francisco
A Framework Of Critical Success Factors For Business Organizations That Lead To Performance Excellence Based On A Financial And Quality Systems Assessment., Melissa Francisco
Electronic Theses and Dissertations
One of the most important tasks that business leaders undertake in order to achieve a superior market position is strategic planning. Beyond this obligation, business owners desire to maximize profit and maintain steady growth. In order to do this, resources must be invested in the most efficient way possible in order to achieve performance excellence. Adjusting business operations quickly, however, especially in times of economic uncertainty, is extremely difficult. Business leaders therefore need insight into which elements of organizational improvement are most effective in order to strategically invest their resources to achieve superior performance in the most efficient way possible. …
Analysis Of Taxi Drivers' Driving Behavior Based On A Driving Simulator Experiment, Jiawei Wu
Analysis Of Taxi Drivers' Driving Behavior Based On A Driving Simulator Experiment, Jiawei Wu
Electronic Theses and Dissertations
Due to comfort, convenience, and flexibility, taxis become more and more prevalent in China, especially in large cities. According to a survey reported by Beijing Traffic Development Research Center, there were 696 million taxi person-rides in Beijing in 2011. However, many violations and road crashes that were related to taxi drivers occurred more frequently. The survey showed that there were a total of 17,242 taxi violations happened in Beijing in only one month in 2003, which accounted for 56% of all drivers' violations. Besides, taxi drivers also had a larger accident rate than other drivers, which showed that nearly 20% …
Computational Fluid Dynamics Simulation Of United Launch Alliance Delta Iv Hydrogen Plume Mitigation Strategies, Stephen Guimond
Computational Fluid Dynamics Simulation Of United Launch Alliance Delta Iv Hydrogen Plume Mitigation Strategies, Stephen Guimond
Electronic Theses and Dissertations
During the launch sequence of the United Launch Alliance Delta IV launch vehicle, large amounts of pure hydrogen are introduced into the launch table and ignited by Radial-Outward-Firing-Igniters (ROFIs). This ignition results in a significant flame, or plume, that rises upwards out of the launch table due to buoyancy. The presence of the plume causes increased and unwanted heat loads on the surface of the vehicle. A proposed solution is to add a series of fans and structures to the existing launch table configuration that are designed to inject ambient air in the immediate vicinity of the launch vehicle's nozzles …
Exploring Sparsity, Self-Similarity, And Low Rank Approximation In Action Recognition, Motion Retrieval, And Action Spotting, Chuan Sun
Electronic Theses and Dissertations
This thesis consists of 4 major parts. In the first part (Chapters 1-2), we introduce the overview, motivation, and contribution of our works, and extensively survey the current literature for 6 related topics. In the second part (Chapters 3-7), we explore the concept of "Self-Similarity" in two challenging scenarios, namely, the Action Recognition and the Motion Retrieval. We build three-dimensional volume representations for both scenarios, and devise effective techniques that can produce compact representations encoding the internal dynamics of data. In the third part (Chapter 8), we explore the challenging action spotting problem, and propose a feature-independent unsupervised framework that …
Cascaded Plasmon Resonances For Enhanced Nonlinear Optical Response, Seyfollah Toroghi
Cascaded Plasmon Resonances For Enhanced Nonlinear Optical Response, Seyfollah Toroghi
Electronic Theses and Dissertations
The continued development of integrated photonic devices requires low-power, small volume all-optical modulators. The weak nonlinear optical response of conventional optical materials requires the use of high intensities and large interaction volumes in order to achieve significant light modulation, hindering the miniaturization of all-optical switches and the development of lightweight transmission optics with nonlinear optical response. These challenges may be addressed using plasmonic nanostructures due to their unique ability to confine and enhance electric fields in sub-wavelength volumes. The ultrafast nonlinear response of free electrons in such plasmonic structures and the fast thermal nonlinear optical response of metal nanoparticles, as …