Engineering Commons^™

A Comparison Of Fpga Implementation Of Latency-Based Solvers For Power Electronic System Real-Time Simulation, Matthew Aaron Milton

Theses and Dissertations

In the design of power systems, real-time simulation is a powerful tool to evaluate and validate designs before dedicating resources to develop such systems. Through use of real-time simulation, one can study the behavior of a power system in interaction with real, physical elements, all while avoiding the cost and risk in constructing and testing such systems before a design is finalized. In recent decades, effort has been made in the industry and academia to apply real-time simulation to that of switching power converters through use of high-speed digital signal processors (DSPs) and field programmable gate array (FPGA) devices. With …

Mathematical Modeling Of Transport And Corrosion Phenomenon Inside High Temperature Molten Salt Systems, Bahareh Alsadat Tavakoli Mehrabadi

Theses and Dissertations

In today's world, alternative clean methods of energy are needed to meet growing energy demands. Concentrating solar thermal power, more commonly referred to as CSP, is unique among renewable energy generators because even though it is variable, like solar photovoltaic and wind, it can easily be coupled with thermal energy storage as well as conventional fuels, making it highly dispatchable. One challenge with concentrated solar power (CSP) systems is the potential corrosion of the alloys in the receivers and heat exchangers at high-temperature (700-1000 °C), which leads to a reduction of heat transfer efficiency and influences the systems durability. The …

Wireless Channel Modeling For Networks On Chips, William Rayess

Theses and Dissertations

The advent of integrated circuit (chip) multiprocessors (CMPs) combined with the continuous reduction in device physical size (technology scaling) to the sub-nanometer regime will result in an exponential increase in the number of processing cores that can be integrated within a single chip. Today’s CMPs already support tens to low hundreds of cores and both industry and academic roadmaps project that future chips will have thousands of cores. Therefore, while there are open questions on how to harness the computing power offered by CMPs, the design of power-efficient and compact on-chip interconnection networks that connects cores, caches and memory controllers …

Deposits Emplaced In Upper Regime, Ricardo Rafael Hernández Moreira

Theses and Dissertations

Relatively common to the submarine setting are depositional sequences that begin with a lower erosional boundary, followed in ascending order by a either a graded or an inherently massive basal unit, a relatively coarse parallel laminated unit, a cross laminated unit, a relatively fine parallel laminated unit, and a capping layer of massive mud. These sequences are present in turbidity current, coastal storm and tsunami deposits, and their study is the key to understanding the physical processes governing sediment transport, erosion and deposition in submarine settings, to the reconstruction of global paleoclimate and paleoflow, to the exploration of hydrocarbon reservoirs …

Hydro-Geological Flow Analysis Using Hidden Markov Models, Chandrahas Raj Venkat Gurram

Theses and Dissertations

Hidden Markov Models a class of statistical models used in various disciplines for understanding speech, finding different types of genes responsible for cancer and much more. In this thesis, Hidden Markov Models are used to obtain hidden states that can correlate the flow changes in the Wakulla Spring Cave. Sensors installed in the tunnels of Wakulla Spring Cave have recorded huge correlated changes in the water flows at numerous tunnels. Assuming the correlated flow changes are a consequence of system being in a set of discrete states, a Hidden Markov Model is calculated. This model comprising all the sensors installed …

A Mechanical Approach To The Characterization Of Material Failure Of Atherosclerotic Lesions, Lindsey A. Davis

Theses and Dissertations

Failure of atherosclerotic plaques can lead to potentially life threatening clinical events such as myocardial infarction (MI), stroke, or transient ischemic attack (TIA). The most frequently described plaque failure mechanism is tensile rupture of the fibrous cap; however, often during angioplasty another plaque failure mechanism occurs in which the atherosclerotic plaque separates from the internal elastic lamina (IEL). This study aims assess the material strength of atherosclerotic lesions using mechanical concepts.

To assess likelihood of plaque dissection at the vessel wall, adhesion strength was assessed in both mouse and human specimens using plaque delamination experiments. Measuring plaque adhesion in transgenic …

Mechanical Characterization Of Sicf-Sicm Nuclear Fuel Cladding By A Novel Hydraulic Internal Pressurization Method, Kirill Shapovalov

Theses and Dissertations

Ceramic Matrix Composites (CMC) have been actively researched for applications requiring high temperature strength and damage tolerance. Examples are turbine engine hot section components, leading edges for hypersonic vehicles, nuclear fusion reactor first wall and blanket, and recently nuclear fuel claddings. Predictable material damage behavior is desirable for these applications so early damage accumulation can be detected before a catastrophic failure occurs. Many ceramic materials can withstand high temperature environments, but due to inherent brittleness of ceramics the high damage tolerance and the predictable damage behavior are difficult to achieve. Ceramic fiber reinforced ceramic composites (CFCC) have demonstrated the above …

A Theoretical Study Of Polymer Based Drug Delivery Systems, Ebtisam Abdullatif Aldaais

Theses and Dissertations

Polymer nanostructured materials for drug delivery applications have witnessed tremendous progress in recent years due to their vast potential. One-end-grafted polymers can form grafted micelles with specific mechanical properties. Biological conditions can alter these properties resulting in the protection or release of drugs. Charged surfactants can also form micelles in an aqueous solution, which can also be manipulated through special conditions. On the micellar surface, self-organized polyelectrolytes can be stimulated to extend their attached ligands and thus increase the probability of binding to targeted receptors. This thesis focuses on modeling polymer-based drug delivery systems by studying the physical interactions between …

Computational Doping For Fuel Cell Material Design Based On Genetic Algorithms And Genetic Programming, Emrah Atilgan

Theses and Dissertations

Developing new materials have historically been time-consuming. Computational material discovery can search large design space to identify promising candidates for experimental verification. Recently, Density Functional Theory (DFT) based first principle calculation has been able to calculate many electrical and physical properties of materials, making them suitable for computational doping based material discovery. In material doping, given a base material, one can change its properties by substituting some elements with new ones or adding additional elements. In computational doping, we have a grid of atoms in a supercell, some of which can be substituted with dopant atoms. There are many possible …

Age-Related Liquefaction Resistance Of Pleistocene Coastal Plain Sands In South Carolina, Michael J. Hasek

Theses and Dissertations

Soils of Pleistocene age in the South Carolina Coastal Plain have experienced liquefaction due to historic and pre-historic earthquakes. Numerous field and laboratory studies have shown that aged soil deposits maintain a greater resistance to liquefaction than younger soil deposits. The currently available methods for assessing liquefaction potential are based on cases in which soils are of Holocene age or younger (< 10,000 yrs). The Pleistocene age soils that were tested and characterized varied in age from about 200,000 years old to 1,400,000 years old. Several sites were investigated using field methods that included the seismic cone penetration test, cone penetration test, standard penetration test, and flat plate dilatometer. Piezometers were installed at the sites. Undisturbed soil samples were retrieved from the subsurface and frozen ex situ to minimize sample disturbance during transportation and laboratory handling. The undisturbed samples were used for cyclic triaxial testing in the laboratory and were tested for shear wave velocity and compression wave velocity using in-cell transducers. Laboratory tests were performed to determine the specific gravity, grain size distribution, moisture content, unit weight, Atterberg limits, Unified Soil Classification, and visual-manual description. Optical petrography and scanning electron microscopy were used to determine the mineral content of the soils, to view grain characteristics, and to view microscopic features that were part of the soil aging process.

Laboratory index tests showed that Pleistocene soils consisted predominately of poorly-graded fine sands, silty sands, and clayey sands. Shear wave velocities from the cyclic triaxial test specimens were comparable to the in situ shear wave velocities measured using …

Expanding The Class Of Globally Convergent Fliess Operators, Irina M. Winter-Arboleda, W. Steven Gray, Luis A. Duffaut Espinosa

Electrical & Computer Engineering Faculty Publications

A common representation of an input-output system in nonlinear control theory is the Chen-Fliess functional series or fliess operator. Such a functional series is said to be globally convergent when there is no a priori upper bound on both the L₁-norm of an admissible input and the length of time over which the corresponding output is well defined. It is known that every Fliess operator having a generating series with Gevrey order 0 ≤ s < 1 is globally convergent. In this paper it is shown that there exists a subset of series with Gevrey order s = 1 which also exhibit global convergence. In particular, the example of Ferfera, which arises in the context of system interconnections, is shown to be one such example.

Nonrecursively Interconnected Fliess Operators Preserve Global Convergence: An Expanded View, Irina M. Winter-Arboleda, Luis A. Duffaut Espinosa, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

A common representation of an input-output system in nonlinear control theory is the Chen-Fliess functional series or Fliess operator. Such a functional series is said to be globally convergent when there is a no a priori upper bound on both the L₁-norm of an admissible input and the length of time over which the corresponding output is well defined. Recent developments have expanded the class of globally convergent Fliess operators. The goal of this paper is to show that the global convergence property is preserved for nonrecursive inter-connections (i.e., the parallel, product and cascade connections) involving this largest known class …

An Improved Smote Algorithm Based On Genetic Algorithm For Imbalanced Data Collection, Qiong Gu, Xian-Ming Wang, Zhao Wu, Bing Ning, Chun-Sheng Xin

Electrical & Computer Engineering Faculty Publications

Classification of imbalanced data has been recognized as a crucial problem in machine learning and data mining. In an imbalanced dataset, minority class instances are likely to be misclassified. When the synthetic minority over-sampling technique (SMOTE) is applied in imbalanced dataset classification, the same sampling rate is set for all samples of the minority class in the process of synthesizing new samples, this scenario involves blindness. To overcome this problem, an improved SMOTE algorithm based on genetic algorithm (GA), namely, GASMOTE was proposed. First, GASMOTE set different sampling rates for different minority class samples. A combination of the sampling rates …

Ultra-Compact Raman Spectrometer For Planetary Explorations, Derek Davis, James Hornef, John Lucas, Hani Elsayed-Ali, M. Nural Abedin

Electrical & Computer Engineering Faculty Publications

To develop a compact Raman spectroscopy system with features that will make it suitable for future space missions which require surface landing. Specifically, this system will be appropriate for any mission in which planetary surface samples need to be measured and analyzed.

Developing A Student Learning Strategy To Bridge Virtual Learning And Hands-On Activity, Gon Namkoong, Hargsoon Yoon, Yonghee Suh

Electrical & Computer Engineering Faculty Publications

This paper addresses the effectiveness of combined virtual and physical hands-on activities in students’ learning which was infused in the capstone senior design project. Senior design projects are open-ended and are similar to the research that scientists perform toward a more comprehensive understanding of nature or new scientific knowledge. As a reinforced learning methodology to greatly assist students’ reasoning and problem-solving skills, virtual learning was first integrated at the planning stage of their projects. This approach is in contrast with the typical senior design courses where only limited resources are available for planning experiments. Using virtual learning, students are able …

Rapid And Accurate C-V Measurements, Ji-Hong Kim, Pragya R. Shrestha, Jason P. Campbell, Jason T. Ryan, David Nminibapiel, Joseph J. Kopanski

Electrical & Computer Engineering Faculty Publications

We report a new technique for the rapid measurement of full capacitance-voltage (C-V) characteristic curves. The displacement current from a 100-MHz applied sine wave, which swings from accumulation to strong inversion, is digitized directly using an oscilloscope from the MOS capacitor under test. A C-V curve can be constructed directly from this data but is severely distorted due to nonideal behavior of real measurement systems. The key advance of this paper is to extract the system response function using the same measurement setup and a known MOS capacitor. The system response correction to the measured C-V curve of the unknown …

Java Computer Animation For Effective Learning Of The Cholesky Algorithm With Transportation Engineering Applications, Ivan Makohon, Duc T. Nguyen, Mecit Cetin

Civil & Environmental Engineering Faculty Publications

In this paper, the well-known Cholesky Algorithm (for solving simultaneous linear equations, or SLE) is re-visited, with the ultimate goal of developing a simple, user-friendly, attractive, and useful Java Visualization and Animation Graphical User Inter-face (GUI) software as an additional teaching tool for students to learn the Cholesky factorization in a step-by-step fashion with computer voice and animation. A demo video of the Cholesky Decomposition (or factorization) animation and result can be viewed online from the website: http://www.lions.odu.edu/~imako001/cholesky/demo/index.html. The software tool developed from this work can be used for both students and their instructors not only to master this technical …

Integration Of Advanced Stiffness-Reduction Techniques Demonstrated In A 3d-Printable Joint, Larry L. Howell, Ezekiel G. Merriam, Kyler A. Tolman

Faculty Publications

his work details the integration of three distinct methods for altering the stiffness of compliant joints: lattice flexures, compound joints, and static balancing. The methodology for applying these strategies is discussed in detail. Lattice flexures are a flexure modification that leads to low motion-direction bending stiffness. Compound joints improve a compliant joint’s load-carrying ability and off-axis stiffness. Static balancing in this case is achieved through the addition of an auxiliary energy storage device. To statically balance a compound lattice-flexured cross-axis flexural pivot, the load-dependent stiffness behavior of a cross-axis flexural pivot (CAFP) with two lattice flexure types is determined. A …

Compound Joints: Behavior And Benefits Of Flexure Arrays, Larry L. Howell, Ezekiel G. Merriam, Jason M. Lund

Faculty Publications

Because compliant mechanisms achieve their motion through deflection of flexible members, they have a limited range of motion and finite stiffness. Many common flexure geometries also suffer from a non-stationary center of rotation. These properties can be obstacles to their adoption in applications that require large displacements, low stiffness, or stationary centers of rotation. This work presents the concept of compound flexures: by assembling arrays of flexures, we can increase range of motion, decrease stiffness, and reduce center shift. We first develop the theory behind some of the basic behavior of compound joints. Then finite element analysis is used to …

Numerical Model Water Quality For Hidalgo County, Texas; Main Drainage System, Jose Orvyl Gonzalez, Grimaldo Carrillo, Jungseok Ho

Civil Engineering Faculty Publications

Increasing urbanization, water intake, and human water interaction of drainage canals of the Hidalgo County watershed seals the drainage basin and expands floodplains along the canal-side. Incremental use of drainage systems affects the amounts of nutrients that can cause an exposure to residues of agriculture chemicals, water related parasitic diseases, and fecal diseases. Proper water quality management is crucial for pollutant transport detection, estimation of non-point source discharge, and prediction of pollutant discharge at water endpoints. This research seeks to improve the understanding stormwater quality and quantity that is influenced by the frequency of human-water contacts and associated with treatment …

Finite Element Modeling And Analysis Applications In Osteogenesis Imperfecta, Jessica M. Fritz, Nicole M. Grosland, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Understanding the biomechanics of bones in persons with osteogenesis imperfecta (OI) is a key component to further understanding the disease, optimizing treatment and quality of life, as well as injury prevention. However, it is not feasible to study bone biomechanics in vivo. Thus, modeling may play a key role in understanding how OI bones respond to the loading experienced during various activities, especially ambulation. Biomechanical modeling can provide insight into bone fracture risks, such as type and location, from single applied loads or repetitive loading. One method for obtaining this information is via a finite element analysis (FEA). FEA is …

Upper Extremity Inverse Dynamics Model For Loftstrand Crutch-Assisted Gait In Children With Osteogenesis Imperfecta, Brooke A. Slavens, Neha Bhagchandani, Mei Wang, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Role Of Micro-Ct In The Visualization, Measurement, And Quantification Of Bone Structure In Osteogenesis Imperfecta, Robert C. Molthen, John Jameson, Carolyne Albert, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Assessing The Spatial Relationship Between Fixation And Foveal Specializations, Melissa A. Wilk, Adam M. Dubis, Robert F. Cooper, Phyllis Summerfelt, Alfredo Dubra, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Increased cone photoreceptor density, an avascular zone (FAZ), and the displacement of inner retinal neurons to form a pit are distinct features of the human fovea. As the fovea provides the majority of our vision, appreciating how these anatomical specializations are related is important for understanding foveal development, normal visual function, and retinal disease. Here we evaluated the relationship between these specializations and their location relative to the preferred retinal locus of fixation (PRL). We measured foveal pit volume, FAZ area, peak cone density, and location of the PRL in 22 subjects with normal vision using optical coherence tomography and …

Exploring Deviant Hacker Networks (Dhn) On Social Media Platforms, Samer Al-Kateeb, Kevin Conlan, Nitin Agarwal, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

Online Social Networks (OSNs) have grown exponentially over the past decade. The initial use of social media for benign purposes (e.g., to socialize with friends, browse pictures and photographs, and communicate with family members overseas) has now transitioned to include malicious activities (e.g., cybercrime, cyberterrorism, and cyberwarfare). These nefarious uses of OSNs poses a signi_cant threat to society, and thus requires research attention. In this exploratory work, we study activities of one deviant groups: hacker groups on social media, which we term Deviant Hacker Networks (DHN). We investigated the connection between different DHNs on Twitter: how they are connected, identified …

Towards Syntactic Approximate Matching-A Pre-Processing Experiment, Doowon Jeong, Frank Breitinger, Hari Kang, Sangjin Lee

Electrical & Computer Engineering and Computer Science Faculty Publications

Over the past few years, the popularity of approximate matching algorithms (a.k.a. fuzzy hashing) has increased. Especially within the area of bytewise approximate matching, several algorithms were published, tested, and improved. It has been shown that these algorithms are powerful, however they are sometimes too precise for real world investigations. That is, even very small commonalities (e.g., in the header of a file) can cause a match. While this is a desired property, it may also lead to unwanted results. In this paper, we show that by using simple pre-processing, we significantly can influence the outcome. Although our test set …

Find Me If You Can: Mobile Gps Mapping Applications Forensic Analysis & Snavp The Open Source, Modular, Extensible Parser, Jason Moore, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

The use of smartphones as navigation devices has become more prevalent. The ubiquity of hand-held navigation devices such as Garmins or Toms Toms has been falling whereas the ownership of smartphones and their adoption as GPS devices is growing. This work provides a comprehensive study of the most popular smartphone mapping applications, namely Google Maps, Apple Maps, Waze, MapQuest, Bing, and Scout, on both Android and iOS. It details what data was found, where it was found, and how it was acquired for each application. Based on the findings, the work allowed for the construction of a tool capable of …

Robot Fish Do Not Need Sentience, Antonio Chella

Animal Sentience

The target article by Key (2016) discusses the thesis that fish cannot feel pain because of the lack of the necessary neural structure. This commentary suggests the possibility that fish do not need conscious neural processing by taking into account recent results from biomimetic robotics. State-of-the-art biomimetic robot fish are based on a tight interaction between the body and the environment and are typically controlled by behavior-based architectures. Therefore, it can be hypothesized that cognitive architectures are not needed to control a robot fish. This is in line with the thesis proposed by Key: what biomimetic robot fish show is …

Suspended Sediment And Nutrient Concentrations And Loads In Two Irish Rivers, Sean T. Harrington

Theses

This thesis presents the results of new and original research on suspended sediment (SS) and nutrient concentrations and loads on the Rivers Bandon and Owenabue in the south of Ireland. It addresses the knowledge gap in SS and nutrient concentration data and in particular SS load/yield estimation methods. A comprehensive database of SS and nutrient concentrations has been established. An investigation into the relationship between water discharge and sediment and nutrient transport is presented and new original relationships between turbidity and suspended sediment concentration (SSC) and nutrients are developed. Turbidity-based suspended sediment loads (SSL) are estimated from the continuous turbidity …

Airborne Collision Detection And Avoidance For Small Uas Sense And Avoid Systems, Laith Rasmi Sahawneh

Theses and Dissertations

The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, …