Engineering Commons^™

The Distributed Independent-Platform Event-Driven Simulation Engine Library (Diesel), Reejo Mathew

Electrical & Computer Engineering Theses & Dissertations

The Distributed, Independent-Platform, Event-Driven Simulation Engine Library (DIESEL) is a simulation executive, capable of supporting both sequential and distributed discrete-event simulations. A system level specification is provided along with the expected behavior of each component within DIESEL. This behavioral specification of each component, along with the interconnection and interaction between the different components, provides a complete description of the DIESEL behavioral model. The model provides a considerable amount of freedom for an application developer to partition the simulation model, when building sequential and distributed applications with respect to balancing the number of events generated across different components. It also allows …

A Resolution Enhancement Technique In Digital Images, Mehmet R. Ormanoglu

Electrical & Computer Engineering Theses & Dissertations

Image enhancement is the processing of images to increase their usefulness. The image enhancement methods and objectives vary with the application. When images are enhanced for human viewers, as in television, the objective is mostly to improve perceptual aspects: image quality, intelligibility, or visual appearance. The aim of this research work is to make the processed image better in the visual sense than the unprocessed image. An image can often be enhanced by modifying its contrast or dynamic range, increasing the sharpness of edges, reducing the noise, or reducing the blurring. The most commonly used contrast enhancement technique is histogram …

Adsorption Of Lead (Ii) Ions By Organosilicate Nanoporous Materials, Larry Keith Isaacs

Civil & Environmental Engineering Theses & Dissertations

As-synthesized organosilicate nanoporous (OSNP) materials HMS (hexagonal mesoporous structure) and MCM-41 were used as adsorbents for removal of lead (II) ions in laboratory batch and column studies. Mesoporous organosilicates were prepared from tetraethylorthosilicate (TEOS) and either an ionic (cetyltrimethyl-ammonium) or neutral (dodecylamine) surfactant. Batch reaction distribution coefficients for MCM-41 were K_D = 51.5 L/g (SD = 26.3) at 24 h and K_D = 73.7 L/g (SD = 40.5) at 7 d. OSNP lead (II) ion adsorption increased from pH = 3 until pH ca. 7.5 after which a sharp decrease in adsorption was noted. OSNP materials reflected a …

Band Gap Engineering Of Two Dimensional Silicon Photonic Crystals By Oxidation And Oxide Etching, Makhin Thitsa

Electrical & Computer Engineering Theses & Dissertations

In this thesis a thorough analysis is presented on the effects of oxidation and oxide etching on the band structure of two dimensional silicon photonic crystals (2 D Si PC's). By using the plane wave expansion method (PWM), two structures of triangular lattice, namely, air cylinders embedded in a silicon background and silicon cylinders embedded in an air background are modeled. The thesis focuses on triangular lattice arrangement because for certain parameter values such a lattice can give rise to absolute band gap, which prohibits the propagation of either transverse electric (TE) or transverse magnetic (TM) polarizations.

During oxidation three …

Detecting Compromised Nodes In Wireless Sensor Networks, Mary Lisa Mathews

Electrical & Computer Engineering Theses & Dissertations

While wireless sensor networks are proving to be a versatile tool, many of the applications in which they are utilized have sensitive data. Therefore, security is crucial in many of these applications. Once a sensor node has been compromised, the security of the network degrades quickly if measures are not taken to deal with this event. There have been many approaches researched to tackle the issue. In this thesis, an anomaly-based intrusion detection protocol is developed to detect compromised nodes in wireless sensor networks.

The proposed protocol is implemented after the sensors are deployed into the environment in which they …

Molecular Dynamics Simulations To Probe Effects Of Ultra-Short, Very-High Voltage Pulses On Cells, Viswanadham Sridhara

Electrical & Computer Engineering Theses & Dissertations

The use of very high electric fields (∼ 100kV/cm or higher) with pulse durations in the nanosecond range (Ultra-short) has been a very recent development in bioelectrics. Traditionally, the electric field effects have mostly been confined to: (a) low field, long-duration pulses, and (b) focused mainly on electroporation studies. Thus, aspects such as possible field-induced DNA damage, calcium release, alterations in neuro-transmitters, or voltage-gating have generally been overlooked.

Ultra-short, high-field pulses open the way to targeted and deliberate apoptotic cell killing (e.g., of tumor cells). Though experimental data is very useful, it usually yields information on macroscopic variables that is …

Filling The Ontology Space For Coalition Battle Management Language, Charles Turnitsa, Curtis Blais, Andreas Tolk

Computational Modeling & Simulation Engineering Faculty Publications

The Coalition Battle Management Language is a language for representing and exchanging plans, orders, and reports across live, constructive and robotic forces in multi-service, multi-national and multi-organizational operations. Standardization efforts in the Simulation Interoperability Standards Organization seek to define this language through three parallel activities: (1) specify a sufficient data model to unambiguously define a set of orders using the Joint Command, Control, and Consultation Information Exchange Data Model (JC3IEDM) as a starting point; (2) develop a formal grammar (lexicon and production rules) to formalize the definition of orders, requests, and reports; (3) develop a formal battle management ontology to …

Applying The Levels Of Conceptual Interoperability Model In Support Of Integratability, Interoperability, And Composability For System-Of-Systems Engineering, Andreas Tolk, Saikou Y. Diallo, Charles D. Turnitsa

Computational Modeling & Simulation Engineering Faculty Publications

The Levels of Conceptual Interoperability Model (LCIM) was developed to cope with the different layers of interoperation of modeling & simulation applications. It introduced technical, syntactic, semantic, pragmatic, dynamic, and conceptual layers of interoperation and showed how they are related to the ideas of integratability, interoperability, and composability. The model was successfully applied in various domains of systems, cybernetics, and informatics.

Self-Consistent Analyses For Potential Conduction Block In Nerves By An Ultrashort High-Intensity Electric Pulse, R. P. Joshi, A. Mishra, Q. Hu, K. H. Schoenbach, A. Pakhomov

Bioelectrics Publications

Simulation studies are presented that probe the possibility of using high-field (>100kV ∕ cm), short-duration (∼50ns) electrical pulses for nonthermal and reversible cessation of biological electrical signaling pathways. This would have obvious applications in neurophysiology, clinical research, neuromuscular stimulation therapies, and even nonlethal bioweapons development. The concept is based on the creation of a sufficiently high density of pores on the nerve membrane by an electric pulse. This modulates membrane conductance and presents an effective "electrical short" to an incident voltage wave traveling across a nerve. Net blocking of action potential propagation can then result. A continuum approach based …

Modeling And Simulations Of Electrical Breakdown And Thermal Failure In Zinc Oxide And Titanium Dioxide For High-Voltage Dielectric Applications, Guogang Zhao

Electrical & Computer Engineering Theses & Dissertations

The development of transmission lines with higher energy storage capabilities is an important goal for compact pulsed power systems. In this context, ceramic dielectrics are promising candidates from the standpoint of high dielectric constants and breakdown strength. Though such materials look promising, their breakdown response characteristics have not been well studied, nor adequately understood. The electrical response of dielectrics also seems to depend on the internal structure and its granularity. For example, the breakdown strength of nano-crystalline insulators such as titania and zinc oxide have been observed to depend on the internal grain size. In general, the hold-off voltage increases …

Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards

Mechanical & Aerospace Engineering Theses & Dissertations

A research effort has been undertaken to investigate critical aspects of launch vehicle performance as affected by variations in specific launch vehicle parameters. The major portion of the study involves liquid propellant systems. However, since solid propellant systems also play a role in today's launch systems, a representative solid-propellant launch vehicle has also been analyzed. The research undertaken determined that the payload capability of a space launch vehicle, or, conversely, the vehicle total liftoff mass, is highly sensitive to the manner in which the space launch vehicle is staged. The research has led to the development and programming of a …

Methodology For Analyzing And Characterizing Error Generation In Presence Of Autocorrelated Demands In Stochastic Inventory Models, Rafael Diaz

Computational Modeling & Simulation Engineering Theses & Dissertations

Most techniques that describe and solve stochastic inventory problems rely upon the assumption of identically and independently distributed (IID) demands. Stochastic inventory formulations that fail to capture serially-correlated components in the demand lead to serious errors. This dissertation provides a robust method that approximates solutions to the stochastic inventory problem where the control review system is continuous, the demand contains autocorrelated components, and the lost sales case is considered. A simulation optimization technique based on simulated annealing (SA), pattern search (PS), and ranking and selection (R&S) is developed and used to generate near-optimal solutions. The proposed method accounts for the …

Tio2 Breakdown Under Pulsed Conditions, G. Zhao, R. P. Joshi, V. K. Lakdawala, E. Schamiloglu, H. Hjalmarson

Electrical & Computer Engineering Faculty Publications

Model studies of current conduction and breakdown in TiO₂ were carried out. Our simulation results indicate that electrical breakdown of TiO₂ under multiple-pulsed conditions can occur at lower voltages as compared to quasi-dc biasing. This is in agreement with recent experimental data and is indicative of a cumulative phenomena. We demonstrate that the lower breakdown voltages observed in TiO₂ under pulsed conditions is a direct rise-time effect, coupled with successive detrapping at the grain boundaries. 2007 American Institute of Physics.

Towards A Diagnostic Framework For Understanding Complex Situations, José J. Padilla, Andres Sousa-Poza, Arturo Tejada, Samuel Kovacic

VMASC Publications

This paper presents a theoretical framework for the concept of understanding and how it can be used for assessing complex situations. Understanding is presented as a cognitive process on how an individual perceives and represents a complex domain based on his/her own predispositions, and how he/she selects knowledge or what may not be knowledge based on the same predispositions towards finding a set of solutions for the situation. Predispositions, in this case, are based on his/her epistemological, ontological and teleological biases while the domain is represented by irreducible and transient conditions. The final outcome is the match or mismatch of …

Dispersion Of Water For Impulse Propagation, Shu Xiao, Karl H. Schoenbach

Bioelectrics Publications

This paper calculates the dispersive loss of water when a Gaussian impulse, or a step function impulse travels over a distance. The minimum risetime t_mr was calculated.

The Shape Of Pulverized Bituminous Vitrinite Coal Particles, Jonathan P. Mathews, Patrick G. Hatcher, Alan W. Scaroni

Chemistry & Biochemistry Faculty Publications

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and …

Training For Adjunct Faculty, Ronald Welch, Allen Estes, Carol Considine

Engineering Technology Faculty Publications

Professor, teacher, instructor, faculty member –all are cherished and incredibly important titles at any university. At the same time, every full-time faculty member knows that it took time to become a good teacher and that training and mentoring shortens the required train-up period. Members of the Civil Engineering Department Heads Council Executive Committee (DHCEC) have indicated that the American Society of Civil Engineers (ASCE) ExCEEd Teaching Workshop is a must have tool for developing new faculty. So why do we thrust a syllabus into the hands of adjunct faculty and wish them well – while it appears that some type …

Bioelectric Effects Of Intense Nanosecond Pulses, Karl H. Schoenbach, Barbara Y. Hargrave, Ravindra P. Joshi, Juergen F. Kolb, Richard Nuccitelli, Christopher J. Osgood, Andrei G. Pakhomov, Michael W. Stacey, James R. Swanson, Jody A. White, Shu Xiao, Jue Zhang, Stephen J. Beebe, Peter F. Blackmore, E. Stephen Buescher

Bioelectrics Publications

Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below the charging time of the outer cell membrane (which is on the order of 100 ns for mammalian cells) causes a strong increase in the probability of electric field interactions with intracellular structures due to displacement currents. For electric field amplitudes exceeding MV/m, such pulses are also expected to allow access to the cell interior through conduction currents flowing through the permeabilized plasma membrane. In both cases, limiting the duration of the electrical pulses to nanoseconds ensures only nonthermal interactions of the electric …

Using Pareto Fronts To Evaluate Polyp Detection Algorithms For Ct Colonography, Adam Huang, Jiang Li, Ronald M. Summers, Nicholas Petrick, Amy K. Hara

Electrical & Computer Engineering Faculty Publications

We evaluate and improve an existing curvature-based region growing algorithm for colonic polyp detection for our CT colonography (CTC) computer-aided detection (CAD) system by using Pareto fronts. The performance of a polyp detection algorithm involves two conflicting objectives, minimizing both false negative (FN) and false positive (FP) detection rates. This problem does not produce a single optimal solution but a set of solutions known as a Pareto front. Any solution in a Pareto front can only outperform other solutions in one of the two competing objectives. Using evolutionary algorithms to find the Pareto fronts for multi-objective optimization problems has been …

Reactive Oxygen Emission From Microwave Discharge Plasmas, S. Popovic, M. Rašković, S. P. Kuo, L. Vuskovic

Physics Faculty Publications

Metastable oxygen atoms and molecules have received increased interest because of their function in surface modification, bio-decontamination and many other industrial applications, in addition to the role in the upper atmospheric layer chemistry. We review work on production and detection of metastable oxygen and we describe our experiments, including the development of techniques for measurement of metastable molecular oxygen. We show that either metastable oxygen molecules or metastable oxygen atoms can be produced in large quantities in electrical discharges, carefully tailored to promote the required kinetics. Although the two species may coexist, colder discharge regimes favor production of molecules, while …

Plasma Treatment Of Bulk Nb Surface In The Ar/Cl2 Discharge, M. Rašković, L. Vuskovic, S. Popovic, A.-M. Valente-Feliciano, L. Phillips

Physics Faculty Publications

The preparation of the cavity walls has been one of the major challenges in the superconducting radio-frequency (SRF) accelerator technology. Therefore, constant research and development effort is devoted to develop surface preparation processes that will improve roughness and lower the level of impurities, like hydrogen or oxygen, embedded in bulk Nb, having in the same time reasonable etching rates. Plasma based surface modification provides an excellent opportunity to achieve these goals. We present Ar/Cl₂ discharge treatment of bulk Nb where we achieved etching rates comparable to the rates obtained with the electropolishing method without introducing impurities in Nb. The …

An Evaluation Of Supercritical Drying And Peg/Freeze Drying Of Waterlogged Archaeological Wood, Eric Schindelholz, Robert Blanchette, Desmond C. Cook, Michael Drews, Steve Hand, Benjamin Held, Joel Jurgens, Betty Seifert

Physics Faculty Publications

This study was undertaken to evaluate the physical effects of drying waterlogged archaeological wood using supercritical carbon dioxide as compared to air drying and the popular polyethylene glycol (PEG)/freeze drying method. Previous studies have shown supercritical drying to be a potentially advantageous alternative to current methods of drying waterlogged wood through reduced processing time, minimal shrinkage, and increased success for reversibility. Samples in the form of blocks and planks of a few centimeters in size were prepared from two archaeological waterlogged wood sources and grouped into three treatment sets: one for air drying, one for PEG/freeze drying, and the other …

Exact And Heuristic Algorithms For The Job Shop Scheduling Problem With Earliness And Tardiness Over A Common Due Date, Leonardo Bedoya-Valencia

Engineering Management & Systems Engineering Theses & Dissertations

Scheduling has turned out to be a fundamental activity for both production and service organizations. As competitive markets emerge, Just-In-Time (JIT) production has obtained more importance as a way of rapidly responding to continuously changing market forces. Due to their realistic assumptions, job shop production environments have gained much research effort among scheduling researchers. This research develops exact and heuristic methods and algorithms to solve the job shop scheduling problem when the objective is to minimize both earliness and tardiness costs over a common due date. The objective function of minimizing earliness and tardiness costs captures the essence of the …

Stochastic Models For Enhancing Agility Of Supply Chains, Alok K. Verma

Engineering Technology Faculty Publications

This paper deals with the application of stochastic inventory model to the three-tier supply chain and verifying the values obtained by mathematical model with discrete event simulation. We investigate three-stage serial supply chain with stochastic demand and fixed replenishment lead-time. Inventory holding costs are charged at each stage, and each stage may incur a consumer backorder penalty cost charged by primary supplier to secondary supplier. The customer-demand follows Poisson distribution. We implement Base Stock model for inventory control at both suppliers. Computer simulation is then designed in such a way that it satisfied all the assumptions for mathematical model. Simulation …

Addressing Student Retention In Engineering And Engineering Technology Through The Use Of A Multidisciplinary Freshman Course, Anthony Dean, Bonita Anthony, Linda Vahala

Engineering Technology Faculty Publications

The Engineering Fundamentals Division of the Batten College of Engineering and Technology (BCET) at Old Dominion University administers a freshman engineering course sequence, along with four engineering departments (Mechanical Engineering, Civil and Environmental Engineering, Aerospace Engineering, and Electrical and Computer Engineering) and the Department of Engineering Technology (which offers degrees in Mechanical Engineering Technology, Civil Engineering Technology and Electrical Engineering Technology). The two course sequence, Exploring Engineering and Technology I and II, involve the five departments in teaching at least one five week module in each of the two courses. Each department generally involves the students in a basic design …

Introducing Freshmen To Construction Estimating And Scheduling Using K'Nex Bridge Kits, Carol Considine, Vernon Lewis

Engineering Technology Faculty Publications

The College of Engineering and Technology at Old Dominion University has developed project-based courses for freshmen engineering students in order to engage them in engineering early with the goal of increasing retention. The courses are divided into three five-week modules that are distributed among the various departments within the college. The Engineering Technology department is responsible for two of the five week modules. One module is comprised of all the engineering technology curriculums; civil, electrical and mechanical, and the other module is strictly a civil engineering technology project.

The civil engineering technology project is focused on the construction industry. Students …

Managing A Distance-Learning Eet Laboratory Course Using Collaboration Software, Steve Hsiung, John Hackworth, Richard Jones, June Ritchie

Engineering Technology Faculty Publications

Methods of managing various distance learning EET laboratory courses using collaboration software are detailed. Particular emphasis is given to different types of collaboration software, advantages and disadvantages of each, and student and faculty feedback on the effectiveness of each.

Identifying University Minors To Support The Construction Specialization Area Within A Civil Engineering Technology Program, Vernon Lewis, Carol Considine

Engineering Technology Faculty Publications

Construction programs at many universities are diversified and provide students with opportunities to examine topic areas that include mechanical and electrical systems, safety, business administration, residential construction, real estate, and management. It is impossible for small civil engineering technology programs with a construction emphasis to encompass all of these expertise areas. As industry looks for students with a knowledge base in these areas, it is incumbent upon programs to find avenues to provide these educational opportunities to their students.

To meet the upper division general education requirements for Old Dominion University, students must have either a minor, second major or …

Multi-Phase Flow Analysis In Oil And Gas Engineering Systems And Its Modelling, Orlando F. Ayala, Luis F. Ayala, Orlando M. Ayala

Engineering Technology Faculty Publications

[Introduction] Two-phase flow is very common in industrial processes and its applications were already in use in ages as remote as the era of Archimedes. At the present time, many industrial processes rely on multi-phase phenomena for the transport of energy and mass or for material processing. During the last century, the nuclear, chemical and petroleum industries propelled intense research activity in the area. Their efforts have been aimed at the demystification of the mechanisms taking place during this complex flow situation.

Enhancing Student Learning In Engineering Technology Programs? A Case For Physical Simulations, Alok Verma

Engineering Technology Faculty Publications

Physical simulations have a proven record as a teaching tool. Concepts that are often hard to grasp are made easy by the use of physical simulation activities. The constructivism learning theory suggests that people learn better by actively participating in the process of learning. According to the Encyclopedia of Educational Technology, "Simulation-based learning involves the placement of a student into a realistic scenario or situation. The student is then responsible for any changes that occur as a result of their decisions." A number of physical simulation based tools have been developed by the author for use as instructional tools to …