Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Electrical and Computer Engineering (1177)
- Civil and Environmental Engineering (668)
- Mechanical Engineering (654)
- Physical Sciences and Mathematics (633)
- Electrical and Electronics (400)
-
- Civil Engineering (373)
- Computer Engineering (341)
- Physics (298)
- Electromagnetics and Photonics (292)
- Optics (270)
- Materials Science and Engineering (267)
- Computer Sciences (249)
- Operations Research, Systems Engineering and Industrial Engineering (249)
- Biomedical Engineering and Bioengineering (229)
- Chemical Engineering (229)
- Industrial Engineering (216)
- Environmental Engineering (188)
- Power and Energy (111)
- Aerospace Engineering (106)
- Transportation Engineering (82)
- Bioresource and Agricultural Engineering (73)
- Life Sciences (70)
- Environmental Sciences (58)
- Biomechanical Engineering (53)
- Medicine and Health Sciences (49)
- Engineering Science and Materials (47)
- Biomechanics and Biotransport (46)
- Social and Behavioral Sciences (46)
- Water Resource Management (44)
- Institution
- Keyword
-
- Daniel Felix Ritchie School of Engineering and Computer Science (332)
- Electrical and Computer Engineering (90)
- Mechanical and Materials Engineering (88)
- Machine learning (67)
- Simulation (65)
-
- Modeling (38)
- Computer vision (37)
- Optimization (32)
- Renewable energy (27)
- Additive manufacturing (26)
- Artificial intelligence (26)
- Computer Science (26)
- Deep learning (26)
- Computational fluid dynamics (22)
- Robotics (22)
- CFD (20)
- Optics (20)
- Finite element analysis (18)
- Remote sensing (18)
- Biomechanics (17)
- Data mining (17)
- MEMS (17)
- Machine Learning (17)
- Heat transfer (16)
- Nonlinear optics (16)
- Classification (15)
- Diffusion (15)
- Microstructure (15)
- Nanoparticles (15)
- Corrosion (14)
- Publication Year
Articles 2311 - 2340 of 4180
Full-Text Articles in Engineering
A Program Manager's Dilemma: Measuring The Effect On Performance Of Different Visual Modalities In Mixed Reality Aerial Door Gunnery, Jonathan Stevens
A Program Manager's Dilemma: Measuring The Effect On Performance Of Different Visual Modalities In Mixed Reality Aerial Door Gunnery, Jonathan Stevens
Electronic Theses and Dissertations
The United States Army continues to develop new and effective ways to use simulation for training. One example is the Non-Rated Crew Member Manned Module (NCM3), a simulator designed to train helicopter crewmembers in critical, high risk tasks such as crew coordination, flight, aerial gunnery, hoist and sling load related tasks. The goal of this study was to evaluate visual modalities' effect on performance in mixed reality aerial door gunnery. There is a strong belief in the United States Army that the greater the degree of immersion in a virtual simulation, the more effective that simulation is. However, little scientific …
Parity-Time And Supersymmetry In Optics, Mohammad Ali Miri
Parity-Time And Supersymmetry In Optics, Mohammad Ali Miri
Electronic Theses and Dissertations
Symmetry plays a crucial role in exploring the laws of nature. By exploiting some of the underlying analogies between the mathematical formalism of quantum mechanics and that of electrodynamics, in this dissertation we show that optics can provide a fertile ground for studying, observing, and utilizing some of the peculiar symmetries that are currently out of reach in other areas of physics. In particular, in this work, we investigate two important classes of symmetries, parity-time symmetry (PT) and supersymmetry (SUSY), within the context of classical optics. The presence of PT symmetry can lead to entirely real spectra in non-Hermitian systems. …
Three-Dimensional Numerical Modeling Of Multiple-Sized Sediment Transport Modeling Under Current And Waves, Qianru Lin
Three-Dimensional Numerical Modeling Of Multiple-Sized Sediment Transport Modeling Under Current And Waves, Qianru Lin
Electronic Theses and Dissertations
In this study, a three-dimensional numerical model of multiple-sized sediment transport under current and waves is developed. The coastal circulations are described by a three-dimensional hydrodynamic model, which is governed by the three-dimensional phase-averaged shallow water flow equations coupled with wave radiation stresses. Methods are also developed to determine the bed shear stress due to current only, waves only, and coexistence of current and waves, accounting for the nonlinear interaction of the current and waves on bed shear stresses. Meanwhile, empirical formulas for bed-load transport capacity, suspended-load transport capacity, and near-bed suspended-load concentration under current and waves are established for …
High-Strain Rate Tensile Characterization Of Graphite Platelet Reinforced Vinyl Ester Based Nanocomposites Using Split-Hopkinson Pressure Bar, Brahmananda Pramanik
High-Strain Rate Tensile Characterization Of Graphite Platelet Reinforced Vinyl Ester Based Nanocomposites Using Split-Hopkinson Pressure Bar, Brahmananda Pramanik
Electronic Theses and Dissertations
The dynamic response of exfoliated graphite nanoplatelet (xGnP) reinforced and carboxyl terminated butadiene nitrile (CTBN) toughened vinyl ester based nanocomposites are characterized under both dynamic tensile and compressive loading. Dynamic direct tensile tests are performed applying the reverse impact Split Hopkinson Pressure Bar (SHPB) technique. The specimen geometry for tensile test is parametrically optimized by Finite Element Analysis (FEA) using ANSYS Mechanical APDL®. Uniform stress distribution within the specimen gage length has been verified using high-speed digital photography. The on-specimen strain gage installation is substituted by a non-contact Laser Occlusion Expansion Gage (LOEG) technique for infinitesimal dynamic tensile strain measurements. …
Critical Analysis Of Transmitarray Antenna Design, Ahmed H. Abdelrahman
Critical Analysis Of Transmitarray Antenna Design, Ahmed H. Abdelrahman
Electronic Theses and Dissertations
In recent years, transmitarray antenna concept attracts growing interests of many scientists in the antenna area. It combines the favorable features of the lens antenna that are based on optical theory and the microstrip arrays that are based on array theory, leading to a low profile design with high gain, high radiation efficiency, and flexible radiation performance. Transmitarrays are now emerging as a new generation of high-gain antennas for long-distance communications. In this dissertation, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented. * detailed analysis of the design of planar space fed array antennas is presented. …
Evaluation Of Cotton Valley "D" Sand Production In Stampede Field, Mississippi, U.S.A., Patrick Lawrence Murphy
Evaluation Of Cotton Valley "D" Sand Production In Stampede Field, Mississippi, U.S.A., Patrick Lawrence Murphy
Electronic Theses and Dissertations
No abstract provided.
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 …
Conae Microwave Radiometer (Mwr) Counts To Brightness Temperature Algorithm, Zoubair Ghazi
Conae Microwave Radiometer (Mwr) Counts To Brightness Temperature Algorithm, Zoubair Ghazi
Electronic Theses and Dissertations
This dissertation concerns the development of the MicroWave Radiometer (MWR) brightness temperature (Tb) algorithm and the associated algorithm validation using on-orbit MWR Tb measurements. This research is sponsored by the NASA Earth Sciences Aquarius Mission, a joint international science mission, between NASA and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE). The MWR is a CONAE developed passive microwave instrument operating at 23.8 GHz (K-band) H-pol and 36.5 GHz (Ka-band) H- and V-pol designed to complement the Aquarius L-band radiometer/scatterometer, which is the prime sensor for measuring sea surface salinity (SSS). MWR measures the Earth's brightness temperature and …
High Resolution Time-Resolved Imaging System In The Vacuum Ultraviolet Region, Yuseong Jang
High Resolution Time-Resolved Imaging System In The Vacuum Ultraviolet Region, Yuseong Jang
Electronic Theses and Dissertations
High-power debris-free vacuum ultraviolet (VUV) light sources have applications in several scientific and engineering areas, such as high volume manufacturing lithography and inspection tools in the semiconductor industry, as well as other applications in material processing and photochemistry. For the past decades, the semiconductor industry has been driven by what is called "Moore's Law". The entire semiconductor industry relies on this rule, which requires chip makers to pack transistors more tightly with every new generation of chips, shrinking the size of transistors. The ability to solve roadmap challenges is, at least partly, proportional to our ability to measure them. The …
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 …
Complementary Layered Learning, Sean Mondesire
Complementary Layered Learning, Sean Mondesire
Electronic Theses and Dissertations
Layered learning is a machine learning paradigm used to develop autonomous robotic-based agents by decomposing a complex task into simpler subtasks and learns each sequentially. Although the paradigm continues to have success in multiple domains, performance can be unexpectedly unsatisfactory. Using Boolean-logic problems and autonomous agent navigation, we show poor performance is due to the learner forgetting how to perform earlier learned subtasks too quickly (favoring plasticity) or having difficulty learning new things (favoring stability). We demonstrate that this imbalance can hinder learning so that task performance is no better than that of a suboptimal learning technique, monolithic learning, which …
Improved Internet Security Protocols Using Cryptographic One-Way Hash Chains, Amerah Alabrah
Improved Internet Security Protocols Using Cryptographic One-Way Hash Chains, Amerah Alabrah
Electronic Theses and Dissertations
In this dissertation, new approaches that utilize the one-way cryptographic hash functions in designing improved network security protocols are investigated. The proposed approaches are designed to be scalable and easy to implement in modern technology. The first contribution explores session cookies with emphasis on the threat of session hijacking attacks resulting from session cookie theft or sniffing. In the proposed scheme, these cookies are replaced by easily computed authentication credentials using Lamport's well-known one-time passwords. The basic idea in this scheme revolves around utilizing sparse caching units, where authentication credentials pertaining to cookies are stored and fetched once needed, thereby, …
Transparent Oxide Semiconductor Gate Based Mosfets For Sensor Applications, Ashwin Kumar Saikumar
Transparent Oxide Semiconductor Gate Based Mosfets For Sensor Applications, Ashwin Kumar Saikumar
Electronic Theses and Dissertations
Starting from small scale laboratories to the highly sophisticated industrial facilities, monitoring and control forms the most integral part. In order to perform this continuous monitoring we require an interface, that would operate between the system and its processing conditions and in turn which facilitates us to act accordingly. This interface is called as a sensor. There are various types of sensors available which have wide range of functionality in various different fields. The use of transparent conducting oxide (TCO) in the field of sensor applications has increased and has been the subject of extensive research. Good electrical properties, good …
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 …
Multimaterial Fibers In Photonics And Nanotechnology, Guangming Tao
Multimaterial Fibers In Photonics And Nanotechnology, Guangming Tao
Electronic Theses and Dissertations
Recent progress in combing multiple materials with distinct optical, electronic, and thermomechanical properties monolithically in a kilometer-long fiber drawn from a preform offers unique multifunctionality at a low cost. A wide range of unique in-fiber devices have been developed in fiber form-factor using this strategy. Here, I summary my recent results in this nascent field of 'multimaterial fibers'. I will focus on my achievements in producing robust infrared optical fibers and in appropriating optical fiber production technology for applications in nanofabrication. The development of optical components suitable for the infrared (IR) is crucial for applications in this spectral range to …
Laser Filamentation - Beyond Self-Focusing And Plasma Defocusing, Khan Lim
Laser Filamentation - Beyond Self-Focusing And Plasma Defocusing, Khan Lim
Electronic Theses and Dissertations
Laser filamentation is a highly complex and dynamic nonlinear process that is sensitive to many physical parameters. The basic properties that define a filament consist of (i) a narrow, high intensity core that persists for distances much greater than the Rayleigh distance, (ii) a low density plasma channel existing within the filament core, and (iii) a supercontinuum generated over the course of filamentation. However, there remain many questions pertaining to how these basic properties are affected by changes in the conditions in which the filaments are formed; that is the premise of the work presented in this dissertation. To examine …
Distribution Of Laser Induced Heating In Multi-Component Chalcogenide Glass And Its Associated Effects, Laura Sisken
Distribution Of Laser Induced Heating In Multi-Component Chalcogenide Glass And Its Associated Effects, Laura Sisken
Electronic Theses and Dissertations
Chalcogenide glasses are well known to have good transparency into the infrared spectrum. These glasses though tend to have low thresholds as compared to oxide glasses for photo-induced changes and thermally-induced changes. Material modification such as photo-induced darkening, bleaching, refractive index change, densification or expansion, ablation of crystallization have been demonstrated, and are typically induced by a thermal furnace-based heat treatment, an optical source such as a laser, or a combination of photo-thermal interactions. Solely employing laser-based heating has an advantage over a furnace, since one has the potential to be able to spatially modify the materials properties with much …
Highly-Sensitive Stoichiometric Analysis Of Yag Ceramics Using Laser-Induced Breakdown Spectroscopy (Libs), Jahromi, Ali Kazemi
Highly-Sensitive Stoichiometric Analysis Of Yag Ceramics Using Laser-Induced Breakdown Spectroscopy (Libs), Jahromi, Ali Kazemi
Electronic Theses and Dissertations
Transparent ceramics are an important class of optical materials with applications in high-strength windows, radiation detectors and high-power lasers. Despite the many successful developments of the past decades, their challenging fabrication still needs to be perfected to achieve a better consistency in optical quality. In particular, ternary phase materials such as Yttrium Aluminum Garnet (YAG, Y3Al5O12), a long standing high-power laser host, require a precise control of stoichiometry, often beyond the precision of current analytical techniques, in order to reduce scattering losses and the presence of deleterious point defects. This work explores the potential of Laser-Induced Breakdown Spectroscopy (LIBS) for …
Broad Bandwidth, All-Fiber, Thulium-Doped Photonic Crystal Fiber Amplifier For Potential Use In Scaling Ultrashort Pulse Peak Powers, Alex Sincore
Electronic Theses and Dissertations
Fiber based ultrashort pulse laser sources are desirable for many applications; however generating high peak powers in fiber lasers is primarily limited by the onset of nonlinear effects such as self-phase modulation, stimulated Raman scattering, and self-focusing. Increasing the fiber core diameter mitigates the onset of these nonlinear effects, but also allows unwanted higher-order transverse spatial modes to propagate. Both large core diameters and single-mode propagation can be simultaneously attained using photonic crystal fibers. Thulium-doped fiber lasers are attractive for high peak power ultrashort pulse systems. They offer a broad gain bandwidth, capable of amplifying sub-100 femtosecond pulses. The longer …
Techniques For Characterization Of Third Order Optical Nonlinearities, Manuel Ferdinandus
Techniques For Characterization Of Third Order Optical Nonlinearities, Manuel Ferdinandus
Electronic Theses and Dissertations
This dissertation describes the development of novel techniques for characterization of nonlinear properties of materials. The dissertation is divided into two parts, a background and theory section and a technique development section. In the background and theory section we explain the origins of the nonlinear optical response of materials across many different spatial and temporal scales. The mechanisms that we are most interested in are the electronic nuclear and reorientational responses, which occur on the range of sub-femtosecond to several picoseconds. The electronic mechanism is due to the electrons of a material experiencing a non-parabolic potential well due a strong …
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 …
Development Of Traffic Safety Zones And Integrating Macroscopic And Microscopic Safety Data Analytics For Novel Hot Zone Identification, Jaeyoung Lee
Electronic Theses and Dissertations
Traffic safety has been considered one of the most important issues in the transportation field. With consistent efforts of transportation engineers, Federal, State and local government officials, both fatalities and fatality rates from road traffic crashes in the United States have steadily declined from 2006 to 2011.Nevertheless, fatalities from traffic crashes slightly increased in 2012 (NHTSA, 2013). We lost 33,561 lives from road traffic crashes in the year 2012, and the road traffic crashes are still one of the leading causes of deaths, according to the Centers for Disease Control and Prevention (CDC). In recent years, efforts to incorporate traffic …
Climate And Landscape Controls On Seasonal Water Balance At The Watershed Scale, Xi Chen
Climate And Landscape Controls On Seasonal Water Balance At The Watershed Scale, Xi Chen
Electronic Theses and Dissertations
The main goal of this dissertation is to develop a seasonal water balance model for evaporation, runoff and water storage change based on observations from a large number of watersheds, and further to obtain a comprehensive understanding on the dominant physical controls on intra-annual water balance. Meanwhile, the method for estimating evaporation and water storage based on recession analysis is improved by quantifying the seasonal pattern of the partial contributing area and contributing storage to base flow during low flow seasons. A new method for quantifying seasonality is developed in this research. The difference between precipitation and soil water storage …
A Human-Centric Approach To Data Fusion In Post-Disaster Managment: The Development Of A Fuzzy Set Theory Based Model, Mubarak Banisakher
A Human-Centric Approach To Data Fusion In Post-Disaster Managment: The Development Of A Fuzzy Set Theory Based Model, Mubarak Banisakher
Electronic Theses and Dissertations
It is critical to provide an efficient and accurate information system in the post-disaster phase for individuals' in order to access and obtain the necessary resources in a timely manner; but current map based post-disaster management systems provide all emergency resource lists without filtering them which usually leads to high levels of energy consumed in calculation. Also an effective post-disaster management system (PDMS) will result in distribution of all emergency resources such as, hospital, storage and transportation much more reasonably and be more beneficial to the individuals in the post disaster period. In this Dissertation, firstly, semi-supervised learning (SSL) based …
An Inter-Domain Supervision Framework For Collaborative Clustering Of Data With Mixed Types., Artur Abdullin
An Inter-Domain Supervision Framework For Collaborative Clustering Of Data With Mixed Types., Artur Abdullin
Electronic Theses and Dissertations
We propose an Inter-Domain Supervision (IDS) clustering framework to discover clusters within diverse data formats, mixed-type attributes and different sources of data. This approach can be used for combined clustering of diverse representations of the data, in particular where data comes from different sources, some of which may be unreliable or uncertain, or for exploiting optional external concept set labels to guide the clustering of the main data set in its original domain. We additionally take into account possible incompatibilities in the data via an automated inter-domain compatibility analysis. Our results in clustering real data sets with mixed numerical, categorical, …
Pulsatile Flow Does Not Improve Efficacy In Ex Vivo Lung Perfusion., Keith A. Zoeller
Pulsatile Flow Does Not Improve Efficacy In Ex Vivo Lung Perfusion., Keith A. Zoeller
Electronic Theses and Dissertations
Introduction Ex vivo lung perfusion (EVLP) has the potential to increase the donor pool for lung transplantation by facilitating extended evaluation of marginal organs. Current methodology employs continuous flow pumps for perfusion. In vivo, continuous flow has been shown to increase pulmonary vascular resistance (PVR). Thus, pulsatile flow EVLP may reduce PVR and improve organ preservation by providing physiologic flow morphology. Methods Lung blocks harvested from male, Yorkshire pigs were allocated into continuous (CF, n=3) and pulsatile flow (PF, n=4) groups. Lungs were ventilated at 4-5 mL/kg, 30% FiO2 and perfused with an acellular, albumin-based solution corrected for osmolarity, acid/base …
Face Recognition In The Wild., Mostafa A. Farag
Face Recognition In The Wild., Mostafa A. Farag
Electronic Theses and Dissertations
Research in face recognition deals with problems related to Age, Pose, Illumination and Expression (A-PIE), and seeks approaches that are invariant to these factors. Video images add a temporal aspect to the image acquisition process. Another degree of complexity, above and beyond A-PIE recognition, occurs when multiple pieces of information are known about people, which may be distorted, partially occluded, or disguised, and when the imaging conditions are totally unorthodox! A-PIE recognition in these circumstances becomes really “wild” and therefore, Face Recognition in the Wild has emerged as a field of research in the past few years. Its main purpose …
Systematic Parameter Analysis For Selective Laser Melting (Slm) Of Silver-Based Materials., Harald Rieper
Systematic Parameter Analysis For Selective Laser Melting (Slm) Of Silver-Based Materials., Harald Rieper
Electronic Theses and Dissertations
Selective Laser Melting (SLM) is a growing technology for the additive manufacturing of parts and structures. Based on a powder layer technique, a laser locally melts the powder and forms new structures. [1] In this approach, silver-based alloy powders will be used. The processing of this kind of material is considered difficult compared to other powder materials such as mild steels or tool steels. Silver powder is a highly reflecting material and has excellent thermal conductivity. Both properties make it difficult to process using Selective Laser Melting. Due to its high price, industries use silver parts as economically as possible …
Geometric Modeling Of Non-Rigid 3d Shapes : Theory And Application To Object Recognition., Mostafa Abdelrahman
Geometric Modeling Of Non-Rigid 3d Shapes : Theory And Application To Object Recognition., Mostafa Abdelrahman
Electronic Theses and Dissertations
One of the major goals of computer vision is the development of flexible and efficient methods for shape representation. This is true, especially for non-rigid 3D shapes where a great variety of shapes are produced as a result of deformations of a non-rigid object. Modeling these non-rigid shapes is a very challenging problem. Being able to analyze the properties of such shapes and describe their behavior is the key issue in research. Also, considering photometric features can play an important role in many shape analysis applications, such as shape matching and correspondence because it contains rich information about the visual …
Charge Collection And Surface Recombination Effects In Organic Bulk Heterojunction Solar Cells., Buddika Ka. Abeyweera 1980-
Charge Collection And Surface Recombination Effects In Organic Bulk Heterojunction Solar Cells., Buddika Ka. Abeyweera 1980-
Electronic Theses and Dissertations
Charge transfer and charge extraction mechanisms are two prevalent issues in the growing field of organic solar cells. Due to their complexity in nature, new methods need to be involved in addressing the fundamental properties associated with organic polymer solar cells. This dissertation has focused on developing a new method to estimate the charge collection lengths and surface recombination lengths of organic polymer solar cells. Photocurrent spectra have been analyzed systematically to observe the dependence on thickness of the active material. A red shift of the peak of the normalized photocurrent with respect to the device thickness has been further …