Digital Commons Network^™

Application Of Queuing Theory And Procedure Time Estimation In A Local Healthcare System, Galina Tsoy

Engineering Management & Systems Engineering Theses & Dissertations

People in the United States pay more for their basic healthcare needs than do people in any other nation in the world. When we consider that the United States is the wealthiest nation in the world, controlling the majority of the world's resources, it seems only reasonable to ask: Why should it be this way?

In an effort to address this problem, this thesis examines two possible methods of improving health care efficiency in hospitals. The thesis is thus in two parts: the first part examines resource allocation in medical units using Queuing Theory, and the second part examines a …

Energy-Landscape-Model Analysis For Irreversibility And Its Pulse-Width Dependence In Cells Subjected To A High-Intensity Ultrashort Electric Pulse, R. P. Joshi, Q. Hu, Karl H. Schoenbach, Stephen J. Beebe

Bioelectrics Publications

We provide a simple, but physical analysis for cell irreversibility and apoptosis in response to an ultrashort (nanosecond), high-intensity electric pulse. Our approach is based on an energy landscape model for determining the temporal evolution of the configurational probability function p(q). The primary focus is on obtaining qualitative predictions of a pulse width dependence to apoptotic cell irreversibility that has been observed experimentally. The analysis couples a distributed electrical model for current flow with the Smoluchowski equation to provide self-consistent, time-dependent transmembrane voltages. The model captures the essence of the experimentally observed pulse-width dependence, and provides a possible physical picture …

Genetic Algorithm-Based Model For Determination Of Efficient Management Strategies For Irrigation Canal Networks, Talaat Taher El Gamel

Civil & Environmental Engineering Theses & Dissertations

An optimization model for the determination of efficient management strategies for an irrigation canal network is developed. The objective is to minimize the total water consumed while satisfying various system constraints. An unsteady flow model is used to simulate the flow in the network. A genetic algorithm- (GA-) based framework is used to solve the model. The suitable GA parameters that should be used within the model, as well as the performance of various constraint-handling techniques, are studied. Uncertainties in crop pattern and water consumption rates are incorporated into the search procedure to identify more reliable solutions. A graphical interface …

Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue

Mechanical & Aerospace Engineering Theses & Dissertations

Naturally nanofluidics has applications demanding the samples to be handled in exceedingly small quantities due to the small size of the fluidic channels in nanofluidic devices, such as characterization of single biomolecules. Fluids confined in channels of nanometer characteristic dimensions exhibit physical behaviors not observed in large conduits. Charge properties of the nanochannel wall in contact with an aqueous solution play essential roles in the involved electrokinetic transport phenomena occurring in nanofluidic devices. In addition to tuning the charge properties of the nanofluidic channel wall by adjusting the solution properties such as pH and background salt concentration, field effect transistor …

Uncertainty Propagation And Robust Design In Cfd Using Sensitivity Derivatives, Michele M. Putko

Mechanical & Aerospace Engineering Theses & Dissertations

This study investigates and demonstrates a methodology for uncertainty propagation and robust design in Computational Fluid Dynamics (CFD). Efficient calculation of both first- and second-order sensitivity derivatives is requisite in the proposed methodology. In this study, first- and second-order sensitivity derivatives of code output with respect to code input are obtained through an efficient incremental iterative approach.

An approximate statistical moment method for uncertainty propagation is first demonstrated on a quasi one-dimensional (1-D) Euler CFD code. This method is then extended to a two-dimensional (2-D) subsonic inviscid model airfoil problem. In each application, given statistically independent, random, normally distributed input …

Qos Provisioning For Multi-Class Traffic In Wireless Networks, Mona El-Kadi Rizvi

Computer Science Theses & Dissertations

Physical constraints, bandwidth constraints and host mobility all contribute to the difficulty of providing Quality of Service (QoS) guarantees in wireless networks. There is a growing demand for wireless networks to support all the services that are available on wired networks. These diverse services, such as email, instant messaging, web browsing, video conferencing, telephony and paging all place different demands on the network, making QoS provisioning for wireless networks that carry multiple classes of traffic a complex problem. We have developed a set of admission control and resource reservation schemes for QoS provisioning in multi-class wireless networks.

We present three …

Pilot Performance And Eye Movement Activity With Varying Levels Of Display Integration In A Synthetic Vision Cockpit, Julie Michele Stark

Psychology Theses & Dissertations

The primary goal of the present study was to investigate the effects of display integration in a simulated commercial aircraft cockpit equipped with a synthetic vision display. Combinations of display integration level (low/high), display view (synthetic vision view/traditional display), and workload (low/high) were presented to each participant. Sixteen commercial pilots flew multiple approaches under IMC conditions in a moderate fidelity fixed-base part-task simulator. Pilot performance data, visual activity, mental workload, and self-report situation awareness were measured.

Congruent with the Proximity Compatibility Principle, the more integrated display facilitated superior performance on integrative tasks (lateral and vertical path maintenance), whereas a less …

Stability Analysis Of Jump-Linear Systems Driven By Finite-State Machines With Markovian Inputs, Sudarshan S. Patilkulkarni

Electrical & Computer Engineering Theses & Dissertations

A control system with a fault recovery mechanism in the feedback loop and with faults occurring in a non-deterministic manner can be modeled as a class of hybrid systems, i.e., a dynamical system switched by a finite-state machine or an automaton. When the plant and controller are linear, such a system can be modeled as a jump-linear system driven by a finite-state machine with a random input process. Such fault recovery mechanisms are found in flight control systems and distributed control systems with communication networks. In these critical applications, closed-loop stability of the system in the presence of fault recoveries …

Dynamical Studies Of Model Membrane And Cellular Response To Nanosecond, High-Intensity Pulsed Electric Fields, Qin Hu

Electrical & Computer Engineering Theses & Dissertations

The dynamics of electroporation of biological cells subjected to nanosecond, high intensity pulses are studied based on a coupled scheme involving the current continuity and Smoluchowski equations. The improved pore formation energy model includes a dependence on pore population and density. It also allows for variable surface tension and incorporates the effects of finite conductivity on the electrostatic correction term, which was not considered by the simple energy models in the literature. It is shown that E(r) becomes self-adjusting with variations in its magnitude and profile. The whole scheme is self-consistent and dynamic.

An electromechanical analysis based on thin-shell theory …

Models, Composability, And Validity, Eric Werner Weisel

Computational Modeling & Simulation Engineering Theses & Dissertations

Composability is the capability to select and assemble simulation components in various combinations into simulation systems to satisfy specific user requirements. The defining characteristic of composability is the ability to combine and recombine components into different simulation systems for different purposes. The ability to compose simulation systems from repositories of reusable components has been a highly sought after goal among modeling and simulation developers. The expected benefits of robust, general composability include reduced simulation development cost and time, increased validity and reliability of simulation results, and increased involvement of simulation users in the process. Consequently, composability is an active research …

Parallel Decomposition Procedures For Large-Scale Linear Programming Problems, Yusong Hu

Civil & Environmental Engineering Theses & Dissertations

In practice, many large-scale linear programming problems are too large to be solved effectively due to the computer's speed and/or memory limitation, even though today's computers have many more capabilities than before. Algorithms are exploited to solve such large linear programming problems, either in the sequential or parallel computation environment. This study focuses on two parallel algorithms for solving large-scale linear programming problems efficiently.

The first parallel decomposition algorithm discussed in this study is from the theory problems in a special block-angular structure. The theory or the decomposition principle is first examined. Since the subproblems of a linear programming problem …

Prediction Of Rigid Body Aircraft Acceleration Response Due To Atmospheric Disturbances, Billy Keith Buck

Mechanical & Aerospace Engineering Theses & Dissertations

Methodology to predict aircraft transient motion resulting from flight within an unsteady atmospheric environment, coupled with validation using flight test data is proposed. A family of five linear dynamic models is developed for describing the normal acceleration throughout an aircraft cabin due to vertical gust excitation. The five models successively build upon each other by incorporating higher fidelity gust penetration effects while simultaneously maintaining a unified modeling framework. Six wind fields reconstructed from flight test data are used to excite the vehicle models. Simulation responses are compared with forward, center, and aft accelerometer response data recorded during the test. Each …

The Relationship Of Project Team Attributes To Project Interim Performance, Vickie S. Parsons

Engineering Management & Systems Engineering Theses & Dissertations

The factors associated with project success, or failure, have not been conclusively resolved in the project management literature. The purpose of this research was to investigate the relationship of project team attributes and interim project performance using a statistical research design. An abundance of research has focused solely on the importance of technical project components as they relate to cost, schedule, or technical performance. However, research into internal team attributes has been sporadic and, generally, associated with subjective measures of project performance or less than optimal statistical techniques. Prior assessment of project performance has also been concentrated at project completion. …

Microdischarge Arrays, Wenhui Shi

Electrical & Computer Engineering Theses & Dissertations

Microhollow cathode discharges (MHCDs) are DC or pulsed gas discharges between two electrodes, separated by a dielectric, and containing a concentric hole. The diameter of the hole, in this hollow cathode configuration, is in the hundred-micrometer range. MHCDs satisfy the two conditions necessary for an efficient excimer radiation sources: (1) high energy electrons which are required to provide a high concentration of excited or ionized rare gas atoms; (2) high pressure operation which favors excimer formation (a three-body process). Flat panel excimer sources require parallel operation of MHCDs. Based on the current-voltage characteristics of MHCD discharges, which have positive slopes …

Generating Series For Interconnected Nonlinear Systems And The Formal Laplace-Borel Transform, Yaqin Li

Electrical & Computer Engineering Theses & Dissertations

Formal power series methods provide effective tools for nonlinear system analysis. For a broad range of analytic nonlinear systems, their input-output mapping can be described by a Fliess operator associated with a formal power series. In this dissertation, the inter connection of two Fliess operators is characterized by the generating series of the composite system. In addition, the formal Laplace-Borel transform of a Fliess operator is defined and its fundamental properties are presented. The formal Laplace-Borel transform produces an elegant description of system interconnections in a purely algebraic context.

Specifically, four basic interconnections of Fliess operators are addressed: the parallel, …

Scaling And Characterization Of Direct Current Glow Discharge Plasma In Atmospheric Air, Abdel-Aleam Hefney Mohamed

Electrical & Computer Engineering Theses & Dissertations

A microhollow cathode discharge was used as a plasma cathode to sustain a stable direct current glow discharge in atmospheric pressure air. The volumetric scale of glow discharge increased from the millimeter to the centimeter range by extending the plasma in lateral and axial directions. In the axial direction, the length of the glow discharge column was varied from 1 mm to 2 cm, with the sustaining voltage increasing linearly with the glow discharge column length. Extension in the lateral direction was obtained by operating discharges in parallel. The glow discharge plasma of the parallel discharge columns was found to …

Astronaut Eva Exposure Estimates From Cad Model Spacesuit Geometry, Giovanni De Angelis, Brooke M. Anderson, William Atwell, John E. Nealy, Gary D. Qualls, John W. Wilson

Mathematics & Statistics Faculty Publications

Ongoing assembly and maintenance activities at the International Space Station (ISS) require much more extravehicular activity (EVA) than did the earlier U.S. Space Shuttle missions. It is thus desirable to determine and analyze, and possibly foresee, as accurately as possible what radiation exposures crew members involved in EVAs will experience in order to minimize risks and to establish exposure limits that must not to be exceeded. A detailed CAD model of the U.S. Space Shuttle EVA Spacesuit, developed at NASA Langley Research Center (LaRC), is used to represent the directional shielding of an astronaut; it has detailed helmet and backpack …

Excimer Emission From Cathode Boundary Layer Discharges, Mohamed Moselhy, Karl H. Schoenbach

Bioelectrics Publications

The excimer emission from direct current glow discharges between a planar cathode and a ring-shaped anode of 0.75 and 1.5 mm diameter, respectively, separated by a gap of 250 μm, was studied in xenon and argon in a pressure range from 75 to 760 Torr. The thickness of the “cathode boundary layer” plasma, in the 100 μm range, and a discharge sustaining voltage of approximately 200 V, indicates that the discharge is restricted to the cathode fall and the negative glow. The radiant excimer emittance at 172 nm increases with pressure and reaches a value of 4 W/cm² for …

Stimulation Of Capacitative Calcium Entry In Hl-60 Cells By Nanosecond Pulsed Electric Fields, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Stephen J. Beebe

Bioelectrics Publications

Nanosecond pulsed electric fields (nsPEFs) are hypothesized to affect intracellular structures in living cells providing a new means to modulate cell signal transduction mechanisms. The effects of nsPEFs on the release of internal calcium and activation of calcium influx in HL-60 cells were investigated by using real time fluorescent microscopy with Fluo-3 and fluorometry with Fura-2. nsPEFs induced an increase in intracellular calcium levels that was seen in all cells. With pulses of 60 ns duration and electric fields between 4 and 15 kV/cm, intracellular calcium increased 200-700 nM, respectively, above basal levels (similar to100 nM), while the uptake of …

How Many Slides? Documented Cytotechnologist Workload, Sophie K, Thompson, Eileen Mason

Medical Diagnostics & Translational Sciences Faculty Publications

(First paragraph) This paper relays workload information obtained as part of an ergonomics survey.1 Data were obtained on the number of slides evaluated daily, workplace setting, hours worked, and demographic information.

Design Optimization Module For Hierarchical Research And Learning Environment, Oktay Baysal, Mehti Koklu, Ahmed K. Noor

Mechanical & Aerospace Engineering Faculty Publications

The present paper describes a learning module on design optimization courses within a hierarchical research and learning network (HRLN). In this environment a knowledge organization can be created as a hierarchical learning network to link diverse inter- and trans- disciplinary teams from a consortium of universities, industry, government agencies and the providers of learning technologies. It is an approach that builds on computer-based training, intelligent tutoring systems, interactive learning, collaborative-distributed learning, and learning networks. The present design optimization module has been developed and described herein, as a demonstrator of a learning module in this environment. This module allows for the …

Enhancing Instruction In Lean Manufacturing Through Development Of Simulation Activities In Shipbuilding Operations, Alok K. Verma, James Hughes, Scott Christman

Engineering Technology Faculty Publications

Lean Manufacturing is a powerful philosophy that advocates minimization of waste within an organization. The adoption of Lean Manufacturing philosophy by major manufacturers has created a demand for qualified personnel in this area. A training program in Lean Enterprise was developed by Old Dominion University for the Apprentice School at Northrop Grumman Newport News. Physical simulation activities are an integral part of this training program. Simulation activities related to shipbuilding operations have been incorporated in the Lean training course. These activities have been used in the Business Operations course for three semesters. Results show increased student participation and better understanding …

Microscopic Analysis For Water Stressed By High Electric Fields In The Prebreakdown Regime, R. P. Joshi, J. Qian, K. H. Schoenbach, E. Schamiloglu

Bioelectrics Publications

Analysis of the electrical double layer at the electrode-water interface for voltages close to the breakdown point has been carried out based on a static, Monte Carlo approach. It is shown that strong dipole realignment, ion-ion correlation, and finite-size effects can greatly modify the electric fields and local permittivity (hence, leading to optical structure) at the electrode interface. Dramatic enhancements of Schottky injection, providing a source for electronic controlled breakdown, are possible. It is also shown that large pressures associated with the Maxwell stress tensor would be created at the electrode boundaries. Our results depend on the ionic density, and …

Using Web Services To Integrate Heterogeneous Simulations In A Grid Environment, J. Mark Pullen, Ryan Brunton, Don Brutzman, David Drake, Michael Hieb, Katherine L. Morse, Andreas Tolk

Computational Modeling & Simulation Engineering Faculty Publications

The distributed information technologies collectively known as Web services recently have demonstrated powerful capabilities for scalable interoperation of heterogeneous software across a wide variety of networked platforms. This approach supports a rapid integration cycle and shows promise for ultimately supporting automatic composability of services using discovery via registries. This paper presents a rationale for extending Web services to distributed simulation environments, including the High Level Architecture (HLA), together with a description and examples of the integration methodology used to develop significant prototype implementations. A logical next step is combining the power of Grid computing with Web services to facilitate rapid …

An Integration Of Pc Hardware & Software In Teaching Engineering Technology Courses, Steve Hsiung, Richard Jones

Engineering Technology Faculty Publications

As technology advances, the price of a PC drops dramatically. This trend has resulted in PCs that are complex, powerful, and very affordable. Today's PC is a popular and essential tool in teaching software programming course(s) in C, C++, Visual Basic, or Java, running commercial software supporting courses in circuit simulation/design or circuit board layout, and acting as a workstation to gain access to the Internet or LAN networks. In most Engineering Technology curricula there is a limited amount of linkage between those PC applications. The actual effort to merge the hard-gained knowledge of hardware & software concepts together through …

Mapping Of Thermo-Fluids Laboratory Experiments Into Web-Based Experiments, Sushil Chaturvedi, Rick Mckenzie, O. A. Akan, A. Priyadershini

Mechanical & Aerospace Engineering Faculty Publications

A methodology is being developed for transforming physical experiments from the undergraduate thermo-fluids laboratory into a web-based virtual experiments. Important characteristics of physical experiments are identified in order to preserve them in physical to virtual domain mapping. Several commercially available software are employed to incorporate in the web-based experiments characteristics such as recreation of physical phenomenon in the virtual domain, measurement of physical quantities on a computer screen, assembly of virtual probes and coupling of the virtual experiment with a data acquisition software. A virtual reality software has been incorporated to enable web-based students to navigate through the virtual laboratory, …

Including Organizational Cultural Parameters In Work Processes, Holly A. H. Handley, Nancy J. Heacox

Engineering Management & Systems Engineering Faculty Publications

Recent work in modeling decision-making work processes has focused on including the national culture of individual decision-makers in order to emphasize the differences in decision criteria between decision-makers of different nationalities. In addition to nationality, a decision-maker is also a member of an organization and brings this organizational culture to his role in the work process, where it may also affect his task performance. In order to represent the organizational impact on the work process, five organizational cultural parameters were identified and included in an algorithm for modeling and simulation of cultural difference in human decision-making. While the five modifiers …

Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner

Computer Science Faculty Publications

Motivated by preservation and resource discovery, we examine how digital resources, and not just metadata about resources, can be harvested using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). We review and critique existing techniques for identifying and gathering digital resources using metadata harvested through the OAI-PMH. We introduce an alternative solution that builds on the introduction of complex object formats that provide a more accurate way to describe digital resources. We argue that the use of complex object formats as OAI-PMH metadata formats results in a reliable and attractive approach for incremental harvesting of resources using the OAI-PMH.

Metadata And Buckets In The Smart Object, Dumb Archive (Soda) Model, Michael L. Nelson, Kurt Maly, Delwin R. Croom Jr., Steven W. Robbins

Computer Science Faculty Publications

We present the Smart Object, Dumb Archive (SODA) model for digital libraries (DLs), and discuss the role of metadata in SODA. The premise of the SODA model is to "push down" many of the functionalities generally associated with archives into the data objects themselves. Thus the data objects become "smarter", and the archives "dumber". In the SODA model, archives become primarily set managers, and the objects themselves negotiate and handle presentation, enforce terms and conditions, and perform data content management. Buckets are our implementation of smart objects, and da is our reference implementation for dumb archives. We also present our …

Automation Laboratory Development With Design Implementation Scheme And Simulation Software, Cheng Y. Lin, Gary R. Crossman

Engineering Technology Faculty Publications

This paper describes the development of the Automation Control Lab in the Mechanical Engineering Technology Program of the Engineering Technology Department at Old Dominion University. The reorganization goal of the development is to help students design, test, and implement their automation designs effectively. Three processes are adopted to achieve this goal: (1) floor-plan design and inventory control of the components, (2) using Automation Studio to dynamically check each design, and (3) using industrial Programmable Logic Controllers (PLC) controllers to download PLC programs.