Computational Engineering Commons^™

The Reflective Mariner An Approach For Ecdis Training And Operational Usage, Scott W. Muller

Computational Modeling & Simulation Engineering Theses & Dissertations

The emergence of the Electronic Chart Display and Information System (ECDIS) on the bridge of modem vessels offers the possibility of improving the safety and efficiency of maritime operations. Despite its benefits, improper use of ECDIS relegates the watch officer to passive monitoring, which in tum places the mariner "out of the control loop" in the assessment of vessel control functions and equipment malfunctions. It is therefore vital to train mariners to be active in their ECDIS monitoring. This thesis presents a training strategy aimed at developing the "Reflective Mariner": an approach to help mariners maintain their active use of …

Factors Affecting National Technological Absorptive Capacity, Karim Fathy Saad

Archived Theses and Dissertations

No abstract provided.

User Friendly Computer Software For Construction Projects Delay Analysis, Kamel Ahmed Salem El Sayed

Archived Theses and Dissertations

Construction industry around the world is facing a huge revolution in terms of number of executed projects. Projects are no longer simple ones managed by few persons. Commercial buildings, high rise towers and bridges are being built everywhere. The majority of these projects are complex ones that face a lot of obstacles. Delays are one of the major obstacles that construction projects face and are very likely to occur. Generally, claims are the result of any delay in the construction progress. To be able to analyze the claim and assign the responsibility, the analyst has to perform a delay analysis. …

A Component Based Formal Ontology Model, A Method For Evaluating Such A Model, And The Results Of An Application Of That Method, Charles Tumitsa

Computational Modeling & Simulation Engineering Theses & Dissertations

For systems to truly communicate effectively, more than just data interchange is necessary. The systems must achieve conceptual interoperability, which implies communicating with understanding.

The LCIM (Levels of Conceptual Interoperability Model) describes a number of levels of interoperability, each of which shows systems with an increased amount of conceptual understanding of the other systems they are communicating with. The lowest levels of this model, technical and syntactic interoperability, are achieved (and there are many existing examples) via data exchange in a number of different ways. Research has shown, however, that to attain higher levels of conceptual understanding, that there must …

A Comparative Analysis Of Air-To-Ground Engagement Outcomes In The Joint Warfare System (Jwars) And The Jwars-Joint Semi-Automated Forces Federation, Melissa Anne St. Peter

Computational Modeling & Simulation Engineering Theses & Dissertations

Multi-resolution modeling is the process by which a single model is created by connecting multiple individual models to describe phenomena at different levels of resolution [1]. "When we change resolutions, replacing a detailed model by a more aggregate one, we must ask whether results are 'consistent'" [2].

There are many methods of determining if the results of two simulations are 'consistent'. However, they are very entailed and require a detailed understanding of the individual models including their functionality, algorithms, and inner workings. A straight forward and rapid way of assessing potential inconsistencies is through a statistical comparison of the model …

Information Visualization Methods And Techniques Using Web Services, Kevin Dupigny

Computational Modeling & Simulation Engineering Theses & Dissertations

Data, even in small amounts, can be difficult to interpret quickly and efficiently. Data domains are continually expanding and making this data available and usable in collaborative data environment is a challenge that was not addressed by legacy systems. Such a framework would make the existence of a global information sharing system feasible. Visualizing this complex dataset presents a complex task for current static interface solutions. A flexible layered service oriented model is presented in this work to approach this challenge. The visual scope of human perception is largely untapped by today's data visualization applications. Human mental processes are adept …

Using Case-Based Reasoning For Spam Filtering, Sarah Jane Delany

Doctoral

pam is a universal problem with which everyone is familiar. Figures published in 2005 state that about 75% of all email sent today is spam. In spite of significant new legal and technical approaches to combat it, spam remains a big problem that is costing companies meaningful amounts of money in lost productivity, clogged email systems, bandwidth and technical support. A number of approaches are used to combat spam including legislative measures, authentication approaches and email filtering. The most common filtering technique is content-based filtering which uses the actual text of the message to determine whether it is spam or …

Information Fusion For Visual Reference Resolution In Dynamic Situated Dialogue., Geert-Jan Kruijff, John D. Kelleher, Nick Hawes

Conference papers

Human-Robot Interaction (HRI) invariably involves dialogue about objects in the environment in which the agents are situated. The paper focuses on the issue of resolving discourse references to such visual objects. The paper addresses the problem using strategies for intra-modal fusion (identifying that different occurrences concern the same object), and inter-modal fusion, (relating object references across different modalities). Core to these strategies are sensori-motoric coordination, and ontology-based mediation between content in different modalities. The approach has been fully implemented, and is illustrated with several working examples

Structural Descriptions In Human-Assisted Robot Visual Learning, Geert-Jan Kruijff, John D. Kelleher, Gregor Berginc, Ales Leonardis

Conference papers

The paper presents an approach to using structural descriptions, obtained through a human-robot tutoring dialogue, as labels for the visual ob ject models a robot learns. The paper shows how structural descriptions can relate models for different aspects of one and the same object, and how relating descriptions for visual models and discourse referents enables incremental updating of model descriptions through dialogue (either robot- or human-initiated). The approach has been implemented in an integrated architecture for human-assisted robot visual learning.

Spatial Prepositions In Context: The Semantics Of Near In The Presence Of Distractor Objects., Fintan Costello, John D. Kelleher

Conference papers

The paper examines how people’s judgements of proximity between two objects are influenced by the presence of a third object. In an experiment participants were presented with images containing three shapes in different relative positions, and asked to rate the acceptability of a locative expression such as ‘the circle is near the triangle’ as descriptions of those images. The results showed an interaction between the relative positions of objects and the linguistic roles that those objects play in the locative expression: proximity was a decreasing function of the distance between the object in the head position in the expression and …

A Fast Parallelized Computational Approach Based On Sparse Lu Factorization For Predictions Of Spatial And Time-Dependent Currents And Voltages In Full-Body Biomodels, Ashutosh Mishra, Ravindra P. Joshi, Karl H. Schoenbach, C. D. Clark Iii

Electrical & Computer Engineering Faculty Publications

Realistic and accurate numerical simulations of electrostimulation of tissues and full-body biomodels have been developed and implemented. Typically, whole-body systems are very complex and consist of a multitude of tissues, organs, and subcomponents with diverse properties. From an electrical standpoint, these can be characterized in terms of separate conductivities and permittivities. Accuracy demands good spatial resolution; thus, the overall tissue/animal models need to be discretized into a fine-grained mesh. This can lead to a large number of grid points (especially for a three-dimensional entity) and can place prohibitive requirements of memory storage and execution times on computing machines. Here, the …

Lattice Quantum Algorithm For The Schrodinger Wave Equation In 2+1 Dimensions With A Demonstration By Modeling Soliton Instabilities, Jeffrey Yepez, George Vahala, Linda L. Vahala

Electrical & Computer Engineering Faculty Publications

A lattice-based quantum algorithm is presented to model the non-linear Schrödinger-like equations in 2 + 1 dimensions. In this lattice-based model, using only 2 qubits per node, a sequence of unitary collide (qubit-qubit interaction) and stream (qubit translation) operators locally evolve a discrete field of probability amplitudes that in the long-wavelength limit accurately approximates a non-relativistic scalar wave function. The collision operator locally entangles pairs of qubits followed by a streaming operator that spreads the entanglement throughout the two dimensional lattice. The quantum algorithmic scheme employs a non-linear potential that is proportional to the moduli square of the wave function. …

Computational Analysis And Validation Of The Hans Head And Neck Support, Kapil Tyagi

Mechanical & Aerospace Engineering Theses & Dissertations

One of the major causes of racing fatalities is basilar skull fracture from excessive head motions and neck loading in a frontal impact. There are many head/neck restraints available in the market but HANS head and neck support has proved to be the most efficient one in sled testing. This paper evaluates and compares the performance of the HANS device in MAthematical DYnamic MOdel (MADYMO) software with the sled testing. The tests were conducted for the frontal impact motions, with a crash pulse of 45 G's.

The goal of the tests was to evaluate the performance of HANS without the …

Modeling And Simulation Of Silicon Photonic Crystals Effect Of Oxidation And Etching, G. M. Haider Ali

Electrical & Computer Engineering Theses & Dissertations

Recent inventions of a silicon Raman laser and a high speed photon modulator might motivate integration of electronic and photonic active devices on the same silicon chip. Passive photonic devices in silicon such as waveguides, couplers and splitters have been developed. Photonic devices must be compatible with standard silicon CMOS fabrication processing in order to achieve the integration. Since CMOS fabrication involves a myriad of process steps, it is important to study the effect of processing on photonic devices. Oxidation and etching, two fundamental processes in silicon technology, are utilized in this thesis to model their effects on silicon photonic …

Monte Carlo Simulation Analysis Of Electron Bombardment Of Gallium Nitride For Particle Detector Applications, James Gibson Bolitho

Electrical & Computer Engineering Theses & Dissertations

Gallium Nitride (GaN) is a relatively new and promising semiconductor material. It is finding its place in commercial applications such as transistors, light-emitting diodes, and in blue lasers. The large bandgap of GaN allows for very low canier densities and high breakdown voltages. This combination results in a greatly reduced background current and noise, and can withstand large applied voltages. In addition, GaN is sturdy and has strong mechanical properties. These are all ideal characteristics for application in high-energy particle detection.

In this thesis, the central goal is to assess the response of a GaN-based particle detector through numerical modeling. …

Strategies For Analysis Of Unimodal And Multimodal Data For Simulation, Anshul Rai Sharma

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this thesis is to provide strategies for analysis for data associated with simulation. Data analysis is an important part of the simulation process. Typically more stress is laid upon the development of the computer simulation while the data analysis takes a back seat. However, the accuracy of a simulation depends on the data driving it. In other words, any simulation is only as accurate as the input data fed into the simulation. Also, the output of simulation should be analyzed properly in order to validly estimate the performance of the system being simulated. The focus of …

Fine-Tuning Of Mass-Spring Model Properties For Simulating Realistic Soft Body Deformation, Sylva A. Girtelschmid

Computational Modeling & Simulation Engineering Theses & Dissertations

Obtaining a well behaved soft-tissue model is one of the most challenging and important tasks in the development of surgical simulation systems. Achieving both accurate and real-time deformation response from a soft-tissue model becomes more difficult as the complexity of the represented anatomy and the degree of deformation increases. One common approach to modeling deformable objects is the Mass-Spring (MS) system method. Mass-Spring systems are attractive to real-time applications due to their relatively low computational requirement and ease of implementation. However, their parameter determination is typically done manually, which becomes tedious when accurate approximation to real-world objects is desired. This …

Electromagnetic Wave Propagation Prediction For Wireless Networks Inside Boeing Fuselages, Mennatoallah Youssef

Electrical & Computer Engineering Theses & Dissertations

Commercial grade software is intended for electromagnetic predictions within office buildings; it was used to develop models to analyze propagation inside airplane fuselages. This study shows that Wireless XGTD and Insite software can accurately predict power propagation within airplane fuselages. Current work uses fuselage models, which contain additional internal components. A comparison was made between empty and full fuselage to examine the effects of internal components. Two propagation model types [Fast 3D and Full 3D] were also compared for accuracy to experimental study. It was concluded that completed fuselages are suggested for further simulation study as well as that the …

An Application And Evaluation Of A Methodology For Testing Operational Level Training Simulations, Karl Dean Neal

Computational Modeling & Simulation Engineering Theses & Dissertations

The Virginia Modeling, Analysis and Simulation Center has developed a methodology for testing operational-level training simulation systems. The methodology is built on analyses of the military tasks that an operational-level simulation is intended to train. These tasks are derived from the U.S. Department of Defense Universal Joint Task List. The methodology analyzes the categories of capabilities the simulation should have to support those tasks based on operational-level-military entities and actions. Cross-referencing the tasks and capabilities leads to functionality items the simulation should have. The methodology focuses on training joint force command tasks and decision making at the operational level of …

Modeling And Simulation Of Photonic Crystal Fibers Using Finite Difference Frequency Domain Method, Md. Khalid Ikram

Electrical & Computer Engineering Theses & Dissertations

Photonic crystal fibers (PCFs) allow guiding light in low-index core. These fibers exhibit properties such as single-mode operation in broad wavelength region. The mode shape and group velocity dispersion can be controlled by designing the microstructures of the cladding. In order to study these properties, a fast, efficient, and highly accurate numerical modeling method is required.

A full-vectorial finite-difference frequency-domain (FDFD) method is implemented. The modal properties of conventional step index fiber and index-guiding PCF are analyzed using this modeling technique. Compared to plane wave expansion and biorthogonal basis methods, FDFD is found to be simple, reliable, and efficient. PCFs …

Bottleneck Analysis Of Cports, Sreekalyana Chakravarthy Kajuluri

Electrical & Computer Engineering Theses & Dissertations

CPortS is a transportation logistics simulation that models the flow of military cargo through a seaport and the interaction of the cargo with the port resources and infrastructure. It provides information about the seaport's capabilities, how the cargo has been handled, how many days the cargo took to clear a particular port area, and the overall throughput of the seaport. The model is highly data intensive since it models the huge traffic in a real seaport.

Bottlenecks reduce system performance. Systems that are traffic intensive or simulations of systems, which are data intensive, encounter bottlenecks, which reduce their performance. In …

Distal Placement Of An End-To-Side Bypass Graft Anastomosis A 3-D Computational Study, John Robert Di Cicco

Mechanical & Aerospace Engineering Theses & Dissertations

A three-dimensional computational fluid dynamics study of blood flow through stenotic arteries has been conducted. Flow phenomena, such as separation regions and turbulence, can be found distal to an arterial stenosis. Frequently, a bypass graft using an end-to-side technique is attached to a stenotic artery to restore adequate blood flow. However, a significant percentage of these grafts fail after thirty postoperative days due to intimal hyperplasia development around the distal anastomosis. Moreover, aberrant wall shear rates have been implicated as a factor in the development of intimal hyperplasia. Thus, the present study examines whether placement of the distal end of …

Interactive Land Use Vrml Application Using Servlet Assist, Suresh Chitithoti

Electrical & Computer Engineering Theses & Dissertations

The integration of VRML and Servlet technologies has the potential to revolutionize web-based simulation visualization. The Interactive Land Use VRML Application (ILUVA) uses Java Servlets enabling one to perform urban planning by taking a virtual land area and add buildings, roadways, landscaping, and other features. The Virtual Reality Modeling Language (VRML) is a web-based technology for specifying and delivering interactive three-dimensional visualizations over a browser. The Java Servlet technology offers several powerful capabilities such as user authentication, session management, database connectivity for maintaining several possibly simultaneous user sessions, and dynamically generated VRML. Save and restore capabilities for any applications are …

Functional Model Of The Army's Initial Capabilities Training Plan (Ictp) Generation Process (Transitioning To A Knowledge-Base Enterprise), Bryon Keith Hartzog

Computational Modeling & Simulation Engineering Theses & Dissertations

Background: The Army's transformation of its requirements and acquisition process to the Joint Capabilities Integration Development System (JCIDS), supporting the paradigm shift from a threat-based to capabilities-based methodology, signifies that the training/ training support business processes must also change. The new Capabilities Integration Development System - Army (CIDS-A) will prevent the development of service-only oriented materiel solutions that do not interoperate. Additionally, the CIDS-A will force early analysis across the Doctrine, Organization, Training, Leader, Material, Personnel, and Facilities (DOTLMPF) focus areas. This early DOTLMPF analysis ensures materiel solutions incorporate dynamic and flexible training/ training support. To efficiently manage the training …

Speaker Normalization For Improved Automatic Speech Recognition For Digital Libraries, Wei Wang

Electrical & Computer Engineering Theses & Dissertations

The context of this thesis work is the improvement of automatic speech recognition (ASR) for use with digital libraries. First, commonly used multimedia file formats and codecs are surveyed with the objective of identifying those formats that preserve speech quality while keeping file sizes compact. The main contribution of the work is a new technique for speaker adaptation based on frequency scale modifications. The frequency scale is modified using a minimum mean square error matching of a spectral template for each speaker to a "typical speaker" spectral template. Each spectral template is computed from the average amplitude-normalized spectra of several …

The Effects Of A Modified Gantt Chart Depicting Schedule Risk, Joseph Allen Hope

Computational Modeling & Simulation Engineering Theses & Dissertations

The tools and methodologies used to manage projects continue to evolve. A popular project management tool for monitoring a project's schedule is the Gantt chart. The Gantt chart provides information about projected start and end times for each task of a project. A critical limitation of the Gantt chart, however, is its inability to depict uncertainty surrounding the project schedule, or project schedule risk. The present study investigated the effectiveness of three alternative formats for depicting schedule risk. The three presentation formats used were a table, a table with a traditional Gantt chart, and a table and a modified Gantt …

Output Analysis Of Configurable Port Simulation, Ravikiran Jogu

Electrical & Computer Engineering Theses & Dissertations

The Configurable Port Simulation (CPortS) is a simulation of military cargo moving through a commercial seaport during a force deployment. CPortS simulates cargo at the individual entity level of detail. Simulation at the individual entity level generates huge amounts of output data making the output analysis difficult. To understand the reasons as to why bottlenecks occur in the process of cargo clearance, an analyst needs to be able to partition the data during analysis, not a priori. This makes the estimation of required graph generation impossible, which demands a very dynamic output analysis tool that can enable the analyst to …

Creating Enterprise Simulations Using High Level Architecture, Anton R. Lidums

Electrical & Computer Engineering Theses & Dissertations

Despite an established need, there are two remaining roadblocks to building distributed simulations and enterprise simulation systems. First, commercial simulation packages and engineering modeling tools are not readily distributable across multiple computers and have traditionally had very little impetus for utilizing a distributable format. Second, although HLA simulations have been built and there are tools to facilitate those efforts, very little has been done or written that specifically describes a "non-standard" integration implementation in sufficient detail to make the process reusable or repeatable. This thesis introduces a proof of concept prototype that was developed to integrate simulations. The paper presents …

Support For Statistical Analysis Of The Configurable Port Simulation (Cports), Saurav Mazumdar

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this thesis is to provide support for statistical analysis of CPortS: a transportation logistics simulation, which models the movement of military traffic through seaports and the interaction of the traffic with port infrastructure. By any standards, CPortS is a very large, data intensive simulation. It provides capabilities for analyzing many important issues such as port clearance and throughput. CPortS was classically run in single run mode. Only a single replication of the simulation was performed and conclusions were drawn from the results obtained. Users and analysts of CPortS performed multiple runs only to see the effect …

Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

The present research is aimed at ascertaining the usefulness of InAs semiconductor material for single photon avalanche photo detectors operating in the Geiger mode at 2 μm wavelengths. InAs is considered as the material suitable for the purpose because of its less bandgap and lower effective mass of the electrons when compared to other semiconductor materials presently in use. Hence, theoretically transient transport properties of bulk InAs are superior and the velocity overshoot phenomena stronger. InAs is a relatively less explored material when compared to other materials like GaAs. The choice of the material is justified with thorough exploration of …