Physical Sciences and Mathematics Commons^™

Strategies For Sensor Data Aggregation In Support Of Emergency Response, X. Wang, A. Walden, M. Weigle, S. Olariu

Computer Science Presentations

PDF of a powerpoint presentation from the Military Communications Conference (MILCOM), Baltimore, Maryland, October 7, 2014. Also available on Slideshare.

Discretized Agent-Based Model Of Infectious Disease Spread That Uses Contact Probability, Tyrell L. Gardner

Computational Modeling & Simulation Engineering Theses & Dissertations

This study uses contact probability in an agent-based model to simulate the spread of an infectious disease. In order to perform the study, the agent-based model must first be discretized into events. Each agent in the model is given its own infectious disease state machine taken from the Susceptible-Exposed-Infected-Recovered (SEIR) model. The agents move between squares in a grid environment where each square represents a group. Groups have a contact probability as an attribute that is used to predict whether an agent comes in close contact with another agent. The transitions between the states in the SEIR model are easily …

Idpal – A Partially-Adiabatic Energy-Efficient Logic Family: Theory And Applications To Secure Computing, Mihail T. Cutitaru

Electrical & Computer Engineering Theses & Dissertations

Low-power circuits and issues associated with them have gained a significant amount of attention in recent years due to the boom in portable electronic devices. Historically, low-power operation relied heavily on technology scaling and reduced operating voltage, however this trend has been slowing down recently due to the increased power density on chips. This dissertation introduces a new very-low power partially-adiabatic logic family called Input-Decoupled Partially-Adiabatic Logic (IDPAL) with applications in low-power circuits. Experimental results show that IDPAL reduces energy usage by 79% compared to equivalent CMOS implementations and by 25% when compared to the best adiabatic implementation. Experiments ranging …

Meshless Mechanics And Point-Based Visualization Methods For Surgical Simulations, Rifat Aras

Computational Modeling & Simulation Engineering Theses & Dissertations

Computer-based modeling and simulation practices have become an integral part of the medical education field. For surgical simulation applications, realistic constitutive modeling of soft tissue is considered to be one of the most challenging aspects of the problem, because biomechanical soft-tissue models need to reflect the correct elastic response, have to be efficient in order to run at interactive simulation rates, and be able to support operations such as cuts and sutures.

Mesh-based solutions, where the connections between the individual degrees of freedom (DoF) are defined explicitly, have been the traditional choice to approach these problems. However, when the problem …

High Dimensional Data Set Analysis Using A Large-Scale Manifold Learning Approach, Loc Tran

Electrical & Computer Engineering Theses & Dissertations

Because of technological advances, a trend occurs for data sets increasing in size and dimensionality. Processing these large scale data sets is challenging for conventional computers due to computational limitations. A framework for nonlinear dimensionality reduction on large databases is presented that alleviates the issue of large data sets through sampling, graph construction, manifold learning, and embedding. Neighborhood selection is a key step in this framework and a potential area of improvement. The standard approach to neighborhood selection is setting a fixed neighborhood. This could be a fixed number of neighbors or a fixed neighborhood size. Each of these has …

Investigation And Optimization Of A New Compact Superconducting Cavity For Deflecting And Crabbing Applications, Subashini Uddika De Silva

Physics Theses & Dissertations

Deflecting and crabbing structures have many applications in current accelerator systems. The primary use of a deflecting cavity is to separate a single beam into multiple beams. A crabbing cavity enables the head-on collision at the interaction point in particle colliders in order to increase the luminosity. The early uses of the deflecting structures have been in the early 1960s: these structures were disk loaded structures operating at room temperature. The crabbing structure which was installed at the NEK electron-positron collider was the first and only operational superconducting cavity of that kind. The most common design of superconducting deflecting and …

Feasibility Of Mainstream Nitrite Oxidizing Bacteria Out-Selection And Anammox Polishing For Enhanced Nitrogen Removal, Pusker Raj Regmi

Civil & Environmental Engineering Theses & Dissertations

Short-cut nitrogen removal avoids nitrite oxidation to nitrate by nitrite oxidizing bacteria (NOB) and allows a) reduction of formed nitrite to nitrogen gas via heterotrophic denitrification and/or b) oxidation of remaining ammonia with formed nitrite to nitrogen gas via anaerobic ammonia oxidation (anammox). The precondition for achieving shortcut nitrogen removal is suppression of NOB, which is favored by warm and high ammonia strength conditions found in internally generated ammonia-rich waste streams through anaerobic digestion of waste solids referred to as sidestreams or reject water. The discovery of anammox bacteria in the mid-1990s, which are capable of transforming NH₄+ …

A Framework For Web Object Self-Preservation, Charles L. Cartledge

Computer Science Theses & Dissertations

We propose and develop a framework based on emergent behavior principles for the long-term preservation of digital data using the web infrastructure. We present the development of the framework called unsupervised small-world (USW) which is at the nexus of emergent behavior, graph theory, and digital preservation. The USW algorithm creates graph based structures on the Web used for preservation of web objects (WOs). Emergent behavior activities, based on Craig Reynolds’ “boids” concept, are used to preserve WOs without the need for a central archiving authority. Graph theory is extended by developing an algorithm that incrementally creates small-world graphs. Graph theory …

Section Abstracts: Astronomy, Mathematics, And Physics With Materials Science

Virginia Journal of Science

Abstracts of the Astronomy, Mathematics, and Physics with Materials Science Section for the 92nd Annual Meeting of the Virginia Academy of Science, May 13-15, 2014, Virginia Commonwealth University, Richmond, Virginia

Simulation Modeling And Analysis Of Customs-Regulated Container Terminal Operations With Multimodal Transportation, Mariam A. Kotachi

Engineering Management & Systems Engineering Theses & Dissertations

World trade has been increasing dramatically in the past two decades and, as a result, container exchange has grown significantly. Consequently and to meet this increase, several container terminals are expanding and many new ones are being established. A port with one or more container terminals is considered a complex system in which many entities interact to accomplish seamless handling of containers inbound and outbound. The level of complexity is drastically heightened for container terminals containing multimodal transportation systems as they typically involve ships, rail, and trucks arriving to one or more terminals delivering containers of different sizes to several …

Assessing Organizational Effectiveness Through The Competing Values Framework A Data Envelopment Approach, Raghavender Macherla

Engineering Management & Systems Engineering Theses & Dissertations

This study proposes a model to diagnose organizations using the mathematical principles of data envelopment analysis (DEA) to the variables generated using competing values framework (CVF) in order to evaluate overall organizational effectiveness. The notion of organizational effectiveness is abstract and difficult to measure due to its complexity and multi-functional nature. Over the years, measurement of organizational effectiveness has remained a challenge due to the lack of agreement on the factors that should be assessed to determine effectiveness. This research is aimed at shedding some light into this topic by using data envelopment analysis as a tool to measure relative …

Assessing The Impact Of Electronic Health Record Systems Implementation On Hospital Patient Perceptions Of Care, Katherine Sofia Palacio Salgar

Engineering Management & Systems Engineering Theses & Dissertations

The delivery of health care services has been impacted by advances in Knowledge Management Information Systems (KMIS) and Information Technology (IT). The literature reveals that Electronic Health Records Systems (EHRs) are a comprehensive KMIS. There is a wide recognition in the body of knowledge that demonstrates the potential of EHRs to transform all aspects of health care services and, in consequence, the performance of Health Care Delivery Organizations (HCDO). Authors of published research also agree that there is a need for more empirical contributions that demonstrate the impact of EHRs upon HCDO. It is argued that in most cases, studies …

Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens

Electrical & Computer Engineering Theses & Dissertations

The licensed wireless spectrum is currently under-utilized by as much as 85%. Cognitive radio networks have been proposed to employ dynamic spectrum access to share this under-utilized spectrum between licensed primary user transmissions and unlicensed secondary user transmissions. Current secondary user opportunistic spectrum access methods, however, remain limited in their ability to provide enough incentive to convince primary users to share the licensed spectrum, and they rely on primary user absence to guarantee secondary user performance. These challenges are addressed by developing a Dynamic Spectrum Co-Access Architecture (DSCA) that allows secondary user transmissions to co-access transparently and concurrently with primary …

Web Archive Services Framework For Tighter Integration Between The Past And Present Web, Ahmed Alsum

Computer Science Theses & Dissertations

Web archives have contained the cultural history of the web for many years, but they still have a limited capability for access. Most of the web archiving research has focused on crawling and preservation activities, with little focus on the delivery methods. The current access methods are tightly coupled with web archive infrastructure, hard to replicate or integrate with other web archives, and do not cover all the users' needs. In this dissertation, we focus on the access methods for archived web data to enable users, third-party developers, researchers, and others to gain knowledge from the web archives. We build …

Fema Region Iii Coastal Flood Study - Hampton Roads Adaptation Forum, Robin Danforth

March 28, 2014: Addressing Current and Future Vulnerability through Floodplain Management

No abstract provided.

Toward A Formalism Of Modeling And Simulation Using Model Theory, Saikou Y. Diallo, Jose Padilla, Ross Gore, Heber Herencia-Zapana, Andreas Tolk

VMASC Publications

This article proposes a Modeling and Simulation (M&S) formalism using Model Theory. The article departs from the premise that M&S is the science that studies the nature of truth using models and simulations. Truth in models and simulations is relative as they seek to answer specific modeling questions. Consequently, truth in M&S is relative because every model is a purposeful abstraction of reality. We use Model Theory to express the proposed formalism because it is built from the premise that truth is relative. The proposed formalism allows us to: (1) deduce formal definitions and explanations of areas of study in …

Repeated Load Relaxation Testing Of Pure Polycrystalline Nickel At Room Temperature Using Nanoindentation, D. E. Stegall, M. A. Mamun, B. Crawford, A, A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

We present the results of repeated relaxation tests using nanoindentation to derive the activation volume of the dislocation velocity and the ratios of the dislocation density and dislocation velocity. An experimental technique, based on classical uniaxial relaxation experiments, was developed to establish a constant strain during repeated load relaxation transients and then to calculate the stiffness of unloading, and therefore the hardness, across the transients with acceptable results. We found that the activation volume of the dislocation velocity from our nanoindentation methodology was in good agreement when compared to the same reported for uniaxial experiments. © 2014 AIP Publishing LLC.

An Unexpected Particle Oscillation For Electrophoresis In Viscoelastic Fluids Through A Microchannel Constriction, Xinyu Lu, Saurin Patel, Meng Zhang, Sang Woo Joo, Shizhi Qian, Amod Ogale, Xiangchun Xuan

Mechanical & Aerospace Engineering Faculty Publications

Electrophoresis plays an important role in many applications, which, however, has so far been extensively studied in Newtonian fluids only. This work presents the first experimental investigation of particle electrophoresis in viscoelastic polyethylene oxide (PEO) solutions through a microchannel constriction under pure DC electric fields. An oscillatory particle motion is observed in the constriction region, which is distinctly different from the particle behavior in a polymer-free Newtonian fluid. This stream-wise particle oscillation continues until a sufficient number of particles form a chain to pass through the constriction completely. It is speculated that such an unexpected particle oscillating phenomenon is a …

Enhancing The Insulation Of Wide-Range Spectrum In The Pva/N Thin Film By Doping Zno Nanowires, Yu-Chen Lin, Ching-Hsiang Vhen, Liang-Yih Chen, Shih-Chieh Hsu, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

In this study, polyvinyl alcohol/nitrogen (PVA/N) hybrid thin films doped with sharp-sword ZnO nanowires with insulating effect and wide-range spectrum are demonstrated for the first time. PVA/N doped ZnO nanocomposites were developed by blending PVA and N-doped ZnO nanowires in water at room temperature. Measurements from the field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman, and photoluminescence emission (PL) spectra of the products show that nitrogen is successfully doped into the ZnO wurtzite crystal lattice. In addition, the refractive index of PVA/N doped ZnO hybrid thin films can be controlled by varying the doped ZnO nanowires under different …

Microfluidic Electrical Sorting Of Particles Based On Shape In A Spiral Microchannel, John Dubose, Xinyu Lu, Saurin Patel, Shizhi Qian, Sang Woo Joo

Mechanical & Aerospace Engineering Faculty Publications

Shape is an intrinsic marker of cell cycle, an important factor for identifying a bioparticle, and also a useful indicator of cell state for disease diagnostics. Therefore, shape can be a specific marker in label-free particle and cell separation for various chemical and biological applications. We demonstrate in this work a continuous-flow electrical sorting of spherical and peanut-shaped particles of similar volumes in an asymmetric double-spiral microchannel. It exploits curvature-induced dielectrophoresis to focus particles to a tight stream in the first spiral without any sheath flow and subsequently displace them to shape-dependent flow paths in the second spiral without any …

A Nonrigid Registration Method For Correcting Brain Deformation Induced By Tumor Resection, Yixun Liu, Chengjun Yao, Fotis Drakopoulos, Jinsong Wu, Liangfu Zhou, Nikos Chrisochoides

Computer Science Faculty Publications

Purpose: This paper presents a nonrigid registration method to align preoperative MRI with intraoperative MRI to compensate for brain deformation during tumor resection. This method extends traditional point-based nonrigid registration in two aspects: (1) allow the input data to be incomplete and (2) simulate the underlying deformation with a heterogeneous biomechanical model.

Methods: The method formulates the registration as a three-variable (point correspondence, deformation field, and resection region) functional minimization problem, in which point correspondence is represented by a fuzzy assign matrix; Deformation field is represented by a piecewise linear function regularized by the strain energy of a heterogeneous biomechanical …

A Distributed Consensus Algorithm For Decision Making In Service-Oriented Internet Of Things, Shancang Li, George Oikonomou, Theo Tryfonas, Thomas M. Chen, Li Da Xu

Information Technology & Decision Sciences Faculty Publications

In a service-oriented Internet of things (IoT) deployment, it is difficult to make consensus decisions for services at different IoT edge nodes where available information might be insufficient or overloaded. Existing statistical methods attempt to resolve the inconsistency, which requires adequate information to make decisions. Distributed consensus decision making (CDM) methods can provide an efficient and reliable means of synthesizing information by using a wider range of information than existing statistical methods. In this paper, we first discuss service composition for the IoT by minimizing the multi-parameter dependent matching value. Subsequently, a cluster-based distributed algorithm is proposed, whereby consensuses are …

Mathematical Methods Applied To Digital Image Processing, Yi-Hung Liu, Chung Hao Chen, Paul C.P. Chao

Electrical & Computer Engineering Faculty Publications

Introduction: Digital image processing (DIP) is an important research area since it spans a variety of applications. Although over the past few decades there has been a rapid rise in this field, there still remain issues to address. Examples include image coding, image restoration, 3D image processing, feature extraction and analysis, moving object detection, and face recognition. To deal with these issues, the use of sophisticated and robust mathematical algorithms plays a crucial role. The aim of this special issue is to provide an opportunity for researchers to publish their latest theoretical and technological achievements in mathematical methods and their …

Stability Of High Band Gap P3ht: Pcbm Organic Solar Cells Using Tiox Interfacial Layer, Kurniawan Foe, Gon Namkoong, Matthew Samson, Enas M. Younes, Ilho Nam, Tarek M. Abdel-Fattah

Electrical & Computer Engineering Faculty Publications

We fabricated a poly [3-hexylthiophene] (P3HT) and [6,6] -phenyl-C61-butyric acid methyl ester (PC₆₁BM with the TiO_x layer. We found that a solution based TiO_x coated at a spin speed of 3000 rpm improved the photon absorption of the active layer. An optimized TiO_x layer was also used as the interfacial layer to investigate the stability of P3HT: PC₆₁BM OPC. After 70 days of storage, we observed that the short-circuit current density (J_SC) dropped by 16.2%, fill factor (FF) dropped by 10.6%, and power conversion efficiency (PCE) dropped approximately by 25%, while …

Polarization Of Bi2te3 Thin Film In A Floating-Gate Capacitor Structure, Hui Yuan, Kai Zhang, Haitao Li, Hao Zhu, John E. Bonevich, Helmut Baumgart, Curt A. Richter, Qiliang Li

Electrical & Computer Engineering Faculty Publications

Metal-Oxide-Semiconductor (MOS) capacitors with Bi₂Te₃ thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi₂Te₃ thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi₂Te₃, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent …

Sensor Selection And Integration To Improve Video Segmentation In Complex Environments, Adam R. Reckley, Wei-Wen Hsu, Chung-Hao Chen, Gangfeng Ma, E-Wen Huang

Electrical & Computer Engineering Faculty Publications

Background subtraction is often considered to be a required stage of any video surveillance system being used to detect objects in a single frame and/or track objects across multiple frames in a video sequence. Most current state-of-the-art techniques for object detection and tracking utilize some form of background subtraction that involves developing a model of the background at a pixel, region, or frame level and designating any elements that deviate from the background model as foreground. However, most existing approaches are capable of segmenting a number of distinct components but unable to distinguish between the desired object of interest and …

Engineering Collaborations In Medical Modeling And Simulation, Frederic D. Mckenzie, Salim Chemlal, Tom Hubbard, Robert E. Kelly, Roderick C. Borgie, David A. Besachio, Michel Audette

Computational Modeling & Simulation Engineering Faculty Publications

Fifty years ago computer science was just beginning to see common acceptance as a growing discipline and very few universities had a computer science department although other departments were utilizing computers and software to enhance their methodologies. We believe modeling and simulation (M&S) is on a similar path. Many other disciplines utilize M&S to enhance their methodologies but we also believe that M&S fundamentals can be essential in making better decisions by utilizing the appropriate model for the problem at hand, expanding the solution space through simulation, and understanding it through visualization and proper analyses. After our students learn these …

Cryogenic Testing Of High-Velocity Spoke Cavities, C. S. Hopper, Hyekyoung Park, J. R. Delayen

Physics Faculty Publications

Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

Rheological Signatures In Limit Cycle Behaviour Of Dilute, Active, Polar Liquid Crystalline Polymers In Steady Shear, M. Gregory Forest, Panon Phuworawong, Qi Wang, Ruhai Zhou

Mathematics & Statistics Faculty Publications

We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9, 5207-5222 (doi:10.1039/c3sm27736d)). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest …

Sensor Selection And Integration To Improve Video Segmentation In Complex Environments, Adam R. Reckley, Wei-Wem Hsu, Chung-Hao Chen, Gangfeng Ma, E-Wen Huang

Civil & Environmental Engineering Faculty Publications

Background subtraction is often considered to be a required stage of any video surveillance system being used to detect objects in a single frame and/or track objects across multiple frames in a video sequence. Most current state-of-the-art techniques for object detection and tracking utilize some form of background subtraction that involves developing a model of the background at a pixel, region, or frame level and designating any elements that deviate from the background model as foreground. However, most existing approaches are capable of segmenting a number of distinct components but unable to distinguish between the desired object of interest and …