Computational Engineering Commons^™

Simulation Of Temperature Distributions In Tissue Upon Laser Pulse Irradiation Including Water Mass Transfer, Deepthi Nagulapally

Electrical & Computer Engineering Theses & Dissertations

Lasers, due to their unique characteristics, have tremendous applications in the medical field. Generally all laser applications in hie-medicine involve the propagation of laser energy through tissue. Energy is deposited giving rise to many physical, hie-chemical, and mechanical effects. Among these are dynamical changes in the local temperature distributions within the tissue. Analysis of the temperature changes requires the creation of an appropriate optical transmission and heat flow model that incorporates user specified laser parameters. Here, a numerical simulation model was developed to study both steady state and time dependent temperature distributions due to pulsed laser radiation within user specified …

A Full-Range, Multi-Variable, Cfd-Based Methodology To Identify Abnormal Near-Wall Hemodynamics In A Stented Coronary Artery, Jonathan Murphy, Fergal Boyle

Articles

The benefit of coronary stent implantation is reduced by excessive intimal hyperplasia which re-narrows the artery and the prevention of which is still a primary concern for clinicians. Abnormal hemodynamics create non-physiological viscous stress on the artery wall, one of the root causes of intimal hyperplasia following stent implantation. A methodology to comprehensively evaluate the viscous stress on the artery wall following stent implantation would be useful to evaluate a stent’s hemodynamic performance. The proposed methodology employs 3D computational fluid dynamics, the variables wall shear stress (WSS), WSS gradient (WSSG), WSS angle gradient (WSSAG) and a statistical analysis to evaluate …

A Low Power Touch Screen Document Viewer, Chris Perfetto

Computer Engineering

This document will cover the requirements, design, implementation and testing of a low power touch screen document viewer to serve as a replacement bulletin board. It was Implemented using a BeagleBoard development board, a 4.3” touchscreen LCD and a SD card with a Ubuntu Linux OS installed. The testing of this device is primarily testing the power consumption. The device is not yet complete and will require further development for it to completely satisfy the requirements.

Ofdm Simulation In Matlab, Paul Guanming Lin

Electrical Engineering

The objective of this project is to demonstrate the concept and feasibility of an OFDM system, and investigate how its performance is changed by varying some of its major parameters. This objective is met by developing a MATLAB program to simulate a basic OFDM system. From the process of this development, the mechanism of an OFDM system can be studied; and with a completed MATLAB program, the characteristics of an OFDM system can be explored.

A Numerical Investigation Of S-Duct Flows With Boundary-Layer Ingestion, Benjamin C. Johnson

Masters Theses and Doctoral Dissertations

The essence of this paper is to report the computational research conducted to further NASA's study of active flow control systems for a flush­-mounted inlet with significant boundary-­layer ingestion (BLI). In conjunction with a NASA-­sponsored research grant, the aim is to further accumulate knowledge and insight on the effectiveness of flow control devices in reducing circumferential distortion. Using Computational Fluid Dynamics (CFD), this study seeks to validate wind tunnel results recorded by the NASA Langley Research Center. After numerically reproducing experimental data, the future goal is use CFD to simulate the interaction between the inlet and turbofan stage. This study …

Pretty Lights, Nicholas (Nick) Delmas, Matthew (Matt) Maniaci

Computer Engineering

Digital media players often include a visualization component that allows a user to watch a visualization synchronized to their music or videos. This project uses the visualization plugin API of an existing media playback program (WinAmp) but it displays its visuals using physical LED lights. Instead of outputting visuals to the computer screen, data is sent over USB to a micro controller that runs the LED lights. This project aims to give users a more visceral visual experience than traditional visualizations on the computer screen.

High Order Finite Elements For Lagrangian Computational Fluid Dynamics, Truman Everett Ellis

Master's Theses

A general finite element method is presented to solve the Euler equations in a Lagrangian reference frame. This FEM framework allows for separate arbitrarily high order representation of kinematic and thermodynamic variables. An accompanying hydrodynamics code written in Matlab is presented as a test-bed to experiment with various basis function choices. A wide range of basis function pairs are postulated and a few choices are developed further, including the bi-quadratic Q2-Q1d and Q2-Q2d elements. These are compared with a corresponding pair of low order bi-linear elements, traditional Q1-Q0 and sub-zonal pressure Q1-Q1d. Several test problems are considered including static convergence …

How To Improve Project Management For Agile Federation Development, Priyanka Kotikalpudi

Engineering Management & Systems Engineering Theses & Dissertations

Developing a simulation federation out of a variety of heterogeneous simulation solutions is a complex task requiring very effective project management support in order to accomplish the common objectives and goals of this M&S federation. This thesis study conducts a detailed survey of available literature to identify the project management methods that can be extended to be applied to manage the development of simulation systems. The literature review led to the following two main results: (a) in general, there is insufficient literature dealing with M&S challenges for project management, (b) in particular, the two challenges of often changing requirements leading …

Determining The Utility Of Technology For Education, Brian Spencer Dillon

Computational Modeling & Simulation Engineering Theses & Dissertations

There is a substantial debate concerning the place of technology in education. This debate has been going on over every technology introduced through at least three millennia although the modern version takes place in journal articles. Technology, in the general sense, is already in the educational arena 1n ways which have become so commonplace that we hardly question them today. More modern technologies, however, meet perpetual resistance in achieving their potential. This paper calls into question the most recent trend in research and suggests a new research paradigm which focuses not only on student achievement, but on a variety of …

Multiscale Transformation Field Analysis Of Progressive Damage In Fibrous Laminates, Yehia Bahei-El-Din, Ritesh Khire, Prabhat Hajela

Centre for Advanced Materials

As part of an ongoing effort to model uncertainty propagation across multiple scales in fibrous laminates, this paper presents a deterministic transformation field analysis for modeling damage progression under membrane forces and bending moments. In this approach, equivalent eigenstresses are computed in the phases and/or plies such that their respective stress components that satisfy the underlying failure criteria are reduced to zero. Superposition of the solutions found for the undamaged laminate under applied loads and under the eigenstress field provide the entire response. Failure criteria are based on stress averages in the fiber and matrix. Damage mechanisms considered are frictional …

Modified Sandwich Structures For Improved Impact Resistance Of Wind Turbine Blades, Yehia Bahei-El-Din, Mostafa Shazly, I. El-Habbal, Y. Elbahy

Centre for Advanced Materials

Wind turbine blades are susceptible to damage due to fatigue as well as impact by flying objects and parts broken off failed blades of nearby wind towers. Localized, permanent compression of the foam core and delamination of the fibrous composite face sheets are typical damage modes and can lead to progressive structural failure. Sandwich structures modified by inclusion of flexible polyurethane (PU) layers within the cross section are examined under both impact and dynamic loads. Finite element models of sandwich structures with conventional and modified designs show that sandwich designs modified with PU interlayes exhibit reduced foam core crushing and …

A Computational Analysis Of Cognitive Effort, Luca Longo, Stephen Barrett

Books/Book Chapters

Cognitive effort is a concept of unquestionable utility in understanding human behaviour. However, cognitive effort has been defined in several ways in literature and in everyday life, suffering from a partial understanding. It is common to say “Pay more attention in studying that subject” or “How much effort did you spend in resolving that task?”, but what does it really mean? This contribution tries to clarify the concept of cognitive effort, by introducing its main influencing factors and by presenting a formalism which provides us with a tool for precise discussion. The formalism is implementable as a computational concept and …

Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha, Florin Bobaru

Department of Engineering Mechanics: Faculty Publications

In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …

Modeling Biological Structures Via Abstract Grammars To Solve Common Problems In Computational Biology, David J. Russell

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Grammars are generally understood to be the set of rules that define the relationships between elements of a language. However, grammars can also be used to elucidate structural relationships within sequences constructed from any finite alphabet. In this work abstract grammars are used to model the primary and secondary structures present in biological data. These grammar models are inferred and applied to efficiently solve various sequence analysis problems in computational biology, including multiple sequence alignment, fragment assembly, database redundancy removal, and structural prediction.

The primary structures, or sequential ordering of symbols, of biological data are first modeled with Lempel-Ziv (LZ) …

Quality-Driven Cross Layer Design For Multimedia Security Over Resource Constrained Wireless Sensor Networks, Wei Wang

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates the …

Sonic Boom Prediction Methods Using Feature-Based Adaptation Of Unstructured Meshes, Jacob Chackasseril Varghese

Masters Theses and Doctoral Dissertations

This study examines the improvement of near-field sonic boom prediction of an inviscid supersonic configuration using two grid generation refinement procedures. The first method uses P_HUGG, a parallel hierarchical Cartesian mesh generation algorithm to generate a volume mesh, with the solution-based mesh adaptation capability of P_HUGG being exploited. The mesh quality was improved using P_OPT, a parallel optimization-based mesh-smoothing program. In the second method, the commercially-available software POINTWISE™ is used for volume mesh generation. Then, P_REFINE, a parallel subdivision refinement code, is used t o adaptively refine the mesh. The effectiveness of capturing far field shocks was examined using TENASI, …

Numerical Simulation Of Mode Transition In A Hydrogen-Fueled Scramjet, Manan Ajay Vyas

Master's Theses - Daytona Beach

The Wind-US computational fluid dynamics (CFD) flow solver was used to simulate dual-mode direct-connect ramjet/scramjet engine flowpath tests conducted in the University of Virginia (UVa) Supersonic Combustion Facility (SCF). The objective was to develop a computational capability within Wind-US to aid current hypersonic research and provide insight to flow as well as chemistry details that are not resolved by instruments available. Computational results are compared with experimental data to validate the accuracy of the numerical modeling. These results include two fuel-off non-reacting and eight fuel-on reacting cases with different equivalence ratios, split between one set with a clean (non-vitiated) air …

A Job-Shop Scheduling Model Using Genetic Algorithm And Giffler Thompson Approach, Nikhil Deepak Bumb

Mechanical & Aerospace Engineering Theses & Dissertations

The major objective of this thesis topic is to study the challenging research subject of job shop scheduling with the intent of optimizing the makespan. The job - shop scheduling problem is one of the hardest combinatorial optimization problems. The main aim of scheduling is an efficient allocation of shared resources like machines, operators or both over time for competing activities.

This research focuses on developing a model for optimizing job shop scheduling problem using genetic algorithm and the Giffler Thompson (priority dispatching rule) technique. Considering different parameters, the model comes up with an appropriate way to schedule the tasks …

A Military Surge In Afghanistan -- Modeling A Focused Security Effort, Brent David Morrow

Computational Modeling & Simulation Engineering Theses & Dissertations

In October of 2001, the United States invaded Afghanistan and ousted the Taliban government. Since their overthrow, the Taliban has pieced together and waged an insurgency to retake Afghanistan. That insurgency has gained momentum and grown in strength while the United States NA TO counterinsurgency effort has decreased in size to about 55,000 troops in 2007. Many factors contribute to the insurgency inside of Afghanistan, from ethnic to economic factors to the failure of the central government. This research used a study of the current state of affairs in Afghanistan and agent-based modeling to determine whether a military troop surge …

Prostate Cancer Biomarker Identification: A Comparative Study, Wenjuan Jiang

Computational Modeling & Simulation Engineering Theses & Dissertations

With the current development of proteomics techniques, the discovery of potential molecular biomarkers for early detection of prostate cancer has been greatly improved. In this thesis, we implemented five classifiers including the support vector machine (SVM), Bayesian Classifier, Decision Tree, Random Forest and the Multilayer perceptron (MLP) to test their effectiveness in prostate cancer biomarker identification using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) tissue imaging data. The classifiers were utilized to discriminate cancer mass spectra from normal ones for the data collected at the Eastern Virginia Medical School (EVMS). There are 94 7 spectra from normal tissues and 27 from …

A Strategic Planning Decision Support Methodology In Emergency Department Preparedness For Mass Casualty Events, Adrian Spencer Benson

Computational Modeling & Simulation Engineering Theses & Dissertations

This study's objective is to design a strategic planning decision support methodology to improve Emergency Department (ED) preparedness for Mass Casualty Events (MCEs). This effort will enable hospital and medical strategic planners to evaluate alternatives which improve ED capacity. This comparative analysis illuminates the relative performance of alternatives involving three improvement scenarios for an ED, involving various increases in trauma bay, examination room, radiology, surgery, and recovery/observation study capacities. To illustrate this decision methodology, a Discrete Event Simulation (DES) was implemented in Arena, and used a mixture of Subject Matter Expert (SME) estimates and appropriate notional data. The design of …

A Framework For Using Modeling And Simulation-Based Methods In Support Of Project Management In A U.S. Department Of Defense Enterprise Architecture Framework Environment, Jose Leprout Bricio-Neto

Computational Modeling & Simulation Engineering Theses & Dissertations

The Enterprise Architecture, Analysis and Project Management (EA2PM) framework developed and proposed in this study enables better evaluation of the ability for enterprise architects, project managers and analysts to share system data using their own domain-specific software tools with a focus on the capability to automatically generate a discrete-event simulation model. EA2PM framework is based on applying a Knowledge Management (KM) construct to establish data and information boundaries, and developing a methodology that allows for high levels of traceability from system architecture's environmental factors through assessment of data and information mediation across domains within a KM system.

An application of …

Label Oriented Clustering For Social Network Groups, Ahmed El Kholy

Archived Theses and Dissertations

No abstract provided.

Convergence, Adaptive Refinement, And Scaling In 1d Peridynamics, Florin Bobaru Ph.D., Mijia Yabg Ph.D., Leonardo F. Alves M.S., Stewart A. Silling Ph.D., Ebrahim Askari Ph.D., Jifeng Xu Ph.D.

Department of Engineering Mechanics: Faculty Publications

We introduce here adaptive refinement algorithms for the non-local method peridynamics, which was proposed (in J. Mech. Phys. Solids 2000; 48:175–209) as a reformulation of classical elasticity for discontinuities and long-range forces. We use scaling of the micromodulus and horizon and discuss the particular features of adaptivity in peridynamics for which multiscale modeling and grid refinement are closely connected. We discuss three types of numerical convergence for peridynamics and obtain uniform convergence to the classical solutions of static and dynamic elasticity problems in 1D in the limit of the horizon going to zero. Continuous micromoduli lead to optimal rates of …

Agent Based Modeling In Computer Graphics And Games, Brian Macnamee

Books/Book Chapters

As graphics technology has improved in recent years, more and more importance has been placed on the behavior of virtual characters in applications set in virtual worlds in areas such as games, movies and simulations. The behavior of virtual characters should be believable in order to create the illusion that these virtual worlds are populated with living characters. This has led to the application of agent-based modeling to the control of these virtual characters. There are a number of advantages of using agent-based modeling techniques which include the fact that they remove the requirement for hand controlling all agents in …

A Markov Based Model For Maintenance And Repair Of Equipment, Deepa Jaishankar

Mechanical & Aerospace Engineering Theses & Dissertations

The failure repair process of a continuously operating device is studied in this research. Different cases that incorporate modeling of equipment deterioration, inspection, and maintenance for optimal maintenance policy are proposed. Markov processes are used to determine state probabilities, and the optimal value of the mean time to preventive maintenance is determined by maximizing the availability of the equipment with respect to the mean time preventive maintenance. The approach uses models that assume that equipment can fail due to both deterioration and random failures. Preventive maintenance can be performed from each working state to avoid deterioration failure. Economic effects are …

An Agent-Based Combat Simulation Framework In Support Of Effect-Based And Net-Centric Evaluation, Robert Joseph Bowen

Computational Modeling & Simulation Engineering Theses & Dissertations

The use of information technologies (IT) and information networks has proliferated in industry as a method to achieve competitive advantage. The U.S. Military and its allies, in recent years, have employed IT to improve the way they conduct operations, speed decision making, and increase the span of control of commanders. This has resulted in a fundamental shift in the way military commanders employ combat units today. These (Information Age) forces no longer have to be able to see each other or even communicate directly in order to synchronize maneuvers. Dispersion is now favored over mass, relying on the IT network …

Virtualization Of Physical Experiments Using Real-Time Data Generation From A Computational Fluid Dynamics Code, Kaustubh A. Dharwadkar

Mechanical & Aerospace Engineering Theses & Dissertations

This work presents a methodology for mapping physical experiments into real-time, web-based virtual experiments. The four broad elements included in the physical-to-virtual experiment transformation methodology are: (a) computer solution of conservation equations of mass and momentum to generate velocity and pressure (virtual) data that serve as the foundation for recreating the physical phenomenon in the virtual domain; (b) use of virtual pressure and velocity sensing devices to generate signals or readings from computed virtual data that can be observed and read on a computer screen; (c) use of visualization software such as Macromedia FLASH to create a highly interactive environment …

Simulation Based Six-Sigma Design For Service Industry, Shantanu Dhananjay Ghate

Mechanical & Aerospace Engineering Theses & Dissertations

The main purpose of this thesis was to develop the dental clinic design using six-sigma principles. Simulation software called Process Model^TM was used to build a primary layout of the clinic. Once the basic design was built, statistical analysis method like D.O.E (design of experiment) was used to generate the data based on different combinations of design parameters viz. number of hygienists, number of x-ray machines and waiting room capacity. These data were further analyzed using Contrast-Effect method, ANOVA and Regression Analysis. In order to incorporate the impact of random factors, Taguchi's methodology was applied. This lead to the …

Engineering Management Framework In Support Of Modeling & Simulation Application For Domain Specific Procurement, Thomas Guy Litwin

Engineering Management & Systems Engineering Theses & Dissertations

A strategic process is desirable for project-based organizations in order for them to be efficient and effective when developing Modeling & Simulation (M&S) systems. This thesis proposes an overarching process that combines traditional M&S and Engineering Management methodologies in a new framework to support M&S organizations during the procurement process.

This thesis proposes both a Strategic Project Management Process (SPMP) and a systems engineering process for M&S federation development projects. The systems engineering process utilizes the artifacts of Model Driven Architecture (MDA) to support building M&S federations driven by operational requirements. Detailed research of this systems engineering process revealed a …