Engineering Commons^™

A Comparative Analysis Of Transmission Control Protocol Improvement Techniques Over Space-Based Transmission Media, Joseph M. Lawson

Theses and Dissertations

The purpose of this study was to assess the throughput improvement afforded by the various TCP optimization techniques, with respect to a simulated geosynchronous satellite system, to provide a cost justification for the implementation of a given enhancement technique. The research questions were answered through model and simulation of a satellite transmission system via a Linux-based network topology; results of the simulation were analyzed primarily via a non-parametric method to ascertain performance differences between the various TCP optimization techniques. It was determined that each technique studied, which included the Space Communication Protocol Standard-Transport Protocol (SCPS-TP), window scale, selective acknowledgements (SACKs), …

Atmospheric-Pressure Plasma Sources For Polymer Surface Modification, Shujun Yang

Electrical & Computer Engineering Theses & Dissertations

Plasma processing is widely used in the microelectronics industry for deposition of thin films. It is also used in etching of semiconductors, metals and organic materials such as photoresists. In addition, plasmas are widely used to modify material surfaces. Plasma surface modification can improve the surface adhesion of polymeric materials, which can be used as insulating layers in multilayer semiconductor structures. In deposition and etching, relatively a large amount of material is added to or removed from the surface. In plasma surface modification, only the surface layer is changed in composition or structure, and no significant amount of material is …

Mechanical Properties And Durability Of A Composite Material At Cryogenic Temperatures, Ray Walton Grenoble

Mechanical & Aerospace Engineering Theses & Dissertations

Several issues relevant to the use of a high-performance graphite-epoxy material in hydrogen storage tank applications have been examined. The tensile properties of IM7/977-2 were evaluated as a function of test temperature and thermal-mechanical load history. The temperature dependent coefficient of thermal expansion (CTE) of unidirectional specimens of the same material was measured between -200°C and 0°C. The effects of test temperature, mechanical loading, and damage state on the leak rate of hydrogen gas through IM7/977-2 laminates were evaluated using a novel test system. Finally, the mechanical properties of several commercially available polymer films, which might prove useful as leak-resistant …

A Multilane Pipelined Architecture For Real Time Enhancement Of Color Video Streams, Adam Redd Livingston

Electrical & Computer Engineering Theses & Dissertations

Video stream enhancement is a key fixture in a wide variety of applications from video surveillance, automatic navigation, medical imagery, to facial/object recognition systems. When a video stream contains non-uniform lighting it can be difficult to obtain what is in the darker regions without over enhancing brighter regions. The Adaptive and Integrated Neighborhood Dependant Approach for Nonlinear Enhancement (AINDANE) algorithm combines a tunable nonlinear transfer function, convolution by a multi-scale Gaussian kernel, and tunable contrast enhancement to address this problem for a single image. Luminance values are tuned based on the global cumulative distribution function (CDF) of an image. Contrast …

Mobius: An Omnidirectional Robotic Platform And Software Architecture For Network Teleoperation, Samuel Aaron Miller

Electrical & Computer Engineering Theses & Dissertations

The following thesis presents the results of a project to develop and test an omnidirectional robotic system (hardware and software) at NASA Langley Research Center's Robotics and Intelligent Machines Lab. The impetus for the project was the unique capabilities of omnidirectional systems. Some of the many potential benefits these systems have include improved material-handling capabilities in constrained environments (such as might be found in extraterrestrial manned habitats), efficient camera-based vehicle teleoperation, and simplified route planning for autonomous robot operations.

The project's focus was to design, build, and test a system that used Mecanum wheels to achieve omnidirectional motion. In addition …

Crisis Management In Projects, Senol Nazikkol

Engineering Management & Systems Engineering Theses & Dissertations

The objective of this investigation is to identify the processes, benefits and important tools of crisis management in projects. Crisis management is a system that helps managers to prevent and overcome crises. In this research, a general review about crisis, crisis management processes and tools are discussed. The research was done by using the information in the literature and expert judgment. This paper can be used by academics as a foundation for further research and development in the area of crisis management in projects. Managers of projects can use this study for improving their projects and project-based organizations' crisis management …

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 …

Process And Product Optimization Techniques - A Comparative Analysis Using Optimization Of Surface Roughness, Amol Suresh Sonje

Mechanical & Aerospace Engineering Theses & Dissertations

Robust design improves the fundamental function of the product or process considering noise factors in DOE. G. Taguchi has made significant advances in the use of experimental design. Taguchi methods are criticized on the basis of failure to deal with interactions, use of SIN ratio and lack of sequential nature of investigation. Response Surface Methodology deals with designing models that represents response in terms of various factors affecting it. Optimization of surface finish is achieved using both Taguchi Methods and Response Surface Methodology.

Dual response approach is a combination of Taguchi methods and RSM techniques in which primary response is …

Computational Aerodynamics Study Of Ahmed Body Car Model, Rajat Trehan

Mechanical & Aerospace Engineering Theses & Dissertations

Vehicle Aerodynamics has been the focus of study by researchers for centuries. This interest can be owed to increasing demand on fuel efficiency, vehicle top speed and acceleration performance. Interior aerodynamics, such as engine cooling, air conditioning, wind noise, stability, and cross wind sensitivity play key role in customer satisfaction. Hence a complete understanding of flow around the vehicle is prerequisite to achieve any of the above parameters. Aerodynamic development of motor vehicle is expensive. Much capital must be invested in test facilities such as wind tunnels and climate tunnels. The models are costly and at the beginning of a …

Strategy For Product Reusability Based On Technical And Economic Model, Srikanth Uppuluri

Mechanical & Aerospace Engineering Theses & Dissertations

Reusing old components is considered the most profitable End-of-Life strategy in the modern day scenario of sustainable manufacturing. Though there is increasing pressure on the product designers worldwide to make reuse possible, the functionality of the products and the economic feasibility have been the main considerations for manufacturers in evaluating the reuse strategy. The quality level of the used product and mainly the economic aspect of disassembling the product have been the main uncertainties confronting the industries to move towards the product recovery strategies like reuse and disassembly. The profitability factor in designing and implementing the technology for disassembly of …

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 …

Numerical Simulations On Machining Of Silicon Carbide, Jerry Jacob

Masters Theses

Experiments were conducted to determine the critical depth of cut for machining of single crystal silicon carbide through Single Point Diamond Turning (SPDT) and fly-cutting, and of CVD coated Silicon Carbide through scratching. The ductile nature of these nominally hard and brittle materials is believed to be the result of a high pressure phase transformation, which generates a plastic zone of material that behaves in a metallic manner. The SPDT experiments have shown chip formation similar to that in metal machining. This metallic behavior is the basis for using AdvantEdge, metal machining simulation software, for comparison to experimental results. The …

Power Anomaly Effects And Costs In Low-Voltage Mobile Power Systems, Shengyi Liu, Charles H. Singer, Roger A. Dougal

Faculty Publications

Electric power anomalies or disturbances can disrupt the normal operation of equipment, accelerate aging, or even cause outright failures thus resulting in increased costs of maintenance and reduced system reliability. Past research on the effects caused by power anomalies has been mostly focused on industrial, commercial, or residential systems, or on power distribution equipment. A literature survey reveals that there is no comprehensive review related to low-voltage (LV) power systems and utilization equipment applicable to military combat vehicles, such as aircraft and ships. This paper summarizes the results of a new literature survey that focused on the causes, effects, and …

Interfaces, Volume 8, Issue 1 - Spring 2006

INTERFACES: Newsletter of the Nebraska Center for Materials and Nanoscience

CONTENTS
From the Director
UNL Team Wins $3M DoD Grant
Recent Achievements of Center Researchers
Nanocomposite Permanent Magnets (by Jeff Shield)
NCMN Welcomes Mathias Schubert
Research Spotlight: Evgeny Tsymbal
Ion Beam Assisted Deposition at UNMC (by Fereydoon Namavar)
For the Ages - Book Projects at NCMN (by Ralph Skomski)

Semiempirical Electromagnetic Modeling Of Crack Detection And Sizing In Cement-Based Materials Using Near-Field Microwave Methods, Jagadish Nadakuduti, Genda Chen, R. Zoughi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Detection and characterization of cracks in cement-based materials is an integral part of damage evaluation for health monitoring of civil structures. Microwave signals are able to penetrate inside of dielectric materials (e.g., cement-based materials) and are sensitive to local, physical, geometrical, and dielectric variations in a structure. This makes microwave nondestructive testing and evaluation (NDT&E) techniques suitable for inspection and health monitoring of civil structures. Near-field microwave NDT&E techniques offer the added advantage of providing high spatial resolution, requiring simple hardware that may be portable, low power, fast, real time, and robust. Additionally, these techniques are noncontact and one-sided. Besides …

Computational Simulation Of Turbulent Forced Convection Flow Over A Horizontal Plate Heater In A Rectangular Channel, Bhagavathi Perumal Natarajan

Masters Theses

The phenomenon of turbulent forced convection in the entry region of a rectangular duct was investigated computationally using commercial CFD software, FLUENT. The Standard k-ε turbulence model from FLUENT was used to model turbulence in the 20mm high x 30mm wide cross-sectional rectangular duct. The operating fluid used for the three-dimensional CFD study was water at an inlet temperature of 90° C, with the velocities ranging from 0.5 m/s to 2 m/s, at 1 atm pressure. A constant heat flux was applied to the base of the rectangular channel with the other flow walls insulated. The heat flux ranged from …

Repair, Inspection And Maintenance Methods Of Steel Bridges, Deepak Koirala

Masters Theses

Transportation infrastructure is the backbone of American commerce & industry at the advent of the 21^st century. Bridges are the key elements of the transportation system of a country. According to National Bridge Inventory 2005, there are approximately six hundred thousand bridges in United States, among them nearly one third of bridges are functionally obsolete. A lack in performance of such structures, with respect to minimum acceptable standards, has direct impact not only on the highway system but also on public safety as well as economic growth. Systematic and well-designed research will provide the most effective approach to the …

Clarifying The Role Of Self-Efficacy And Metacognition As Indicators Of Learning: Construct Development And Test, Trevor T. Moores, Jerry Cha-Jan Chang, Deborah K. Smith

Management, Entrepreneurship and Technology Faculty Research

We propose extending our understanding of self-efficacy by comparing self-efficacy with a related construct called metacognition. Metacognition involves the monitoring and control of one's thought processes and is often related, as is self-efficacy, to performance on a task. We develop an instrument that attempts to measure both self-efficacy and metacognition with respect to one's performance on a test covering declarative and procedural knowledge (knowing that, and knowing how) of DFDs and ERDs. With data collected from a sample of 124 students, we use partial least squares (PLS) to show that self-efficacy and metacognition are distinct yet related constructs. While self-efficacy …

Dual-Polarized Microwave Near-Field Reflectometer For Non-Invasive Inspection Of Carbon Fiber Reinforced Polymer (Cfrp) Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Carbon fiber reinforced polymer (CFRP) composites are increasingly being used in strengthening structures of civil infrastructures, aerospace and automotive industries. Subsequent to the application of CFRP, detection and evaluation of the structural integrity of the member becomes a critical issue. Microwave non-invasive inspection techniques have been successfully used for inspecting these structures. A novel inspection system with a dual-polarized microwave near-field waveguide probe for detecting defects such as disbond between CFRP laminates and strengthened structures is presented. It is shown that this system provides automatic removal of the influence of undesired standoff distance (or surface roughness) variations. It may simultaneously …

Inspection Of Spray On Foam Insulation (Sofi) Using Microwave And Millimeter Wave Synthetic Aperture Focusing And Holography, Joseph Toby Case, Frank L. Hepburn, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The Space Shuttle Columbia's catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking and significantly damaging the left wing of the orbiter, which may have been due to a flawed section of SOFI. Microwave and millimeter wave nondestructive evaluation (NDE) methods have shown great potential detecting anomalies in SOFI such as small air voids using a horn and lens in a (real) focused configuration. Synthetic focusing methods may also be used to detect air voids in SOFI and may additionally offer the ability to locate the defect in …

Jitter Analysis Of Pwm Scheme In High Speed Serial Link, Rui Tang, Yong-Bin Kim, Minsu Choi, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a jitter analysis method for PWM (pulse width modulation) scheme in high-speed serial links. The data rate of PWM with N different pulse widths (PWM-N) scheme is (log₂N) x (symbol rate). However it increases the timing jitter of the transmitted signal. The timing jitter is determined by the pulse widths of PWM symbols and the characteristics of the communication channel. The analysis of the first-order systems and the second-order systems demonstrates that data dependent jitter (DDJ) strongly depends on the -3dB frequency and the damping ratio of the systems. The proposed jitter analysis method makes …

Cs 141: Computer Programming - I, Michael Ondrasek

Computer Science & Engineering Syllabi

This course provides a general introduction to the fundamentals of computer programming. Examples from and applications to a broad range of problems are given. No prior knowledge of programming is assumed. The concepts covered will be applied to the Java programming language. Students must register for both lecture and one laboratory section. 4 credit hours. Prerequisite: MTH 127 (College Algebra) or equivalent.

Cs 209: Computer Programming For Business Ii, Dennis Kellermeier

Computer Science & Engineering Syllabi

No abstract provided.

Cs 240: Introduction To Computer Science I, Praveen Kakumanu

Computer Science & Engineering Syllabi

This course is the first in the three course sequence "Introduction to Computer Science" offered by the Computer Science department, WSU. This course presents a general introduction to C++ programming language. It introduces the fundamental capabilities of C++ language as a problem solving tool. Topics include data representation. debugging and program verification. Note: For all CS 24X students, concurrent registration into CS 24X lab is a must.

Cs 242-02: Computer Science Iii, Eric Maston

Computer Science & Engineering Syllabi

This is the third and final course in the Introduction to Computer Science series. This course focuses on data structures with abstract data types, such as trees, stacks, queues and tables.

Cs 466/666: Introduction To Formal Languages, Thomas Sudkamp

Computer Science & Engineering Syllabi

CS 466/666 is an introduction to formal language and automata theory. In this course we will examine methods for defining syntax of languages and recognizing patterns: the syntax of languages can be defined using grammars and patterns accepted by finite state machines. Along with presenting the fundamentals of these two topics, the course will develop and investigate the relationships between language definition and pattern recognition. The text will be the third edition of Languages and Machines: An Introduction to the Theory of Computer Science.

Cs 205-07: Computer Literacy And Office Automation, John P. Herzog

Computer Science & Engineering Syllabi

Basic computer terminology, word processing, spreadsheets, databases, and graphics.

Cs 214: Object-Based Programming, Eric Maston

Computer Science & Engineering Syllabi

This course is a basic introduction to object oriented programming utilizing the Visual Basic programming language.

Cs 208: Computer Programming For Business I, Dennis Kellermeier

Computer Science & Engineering Syllabi

No abstract provided.

Cs 241-01: Computer Science Ii, L. Jane Lin

Computer Science & Engineering Syllabi

This course is the second in the three course sequence "Introduction to Computer Science" offered by the Computer Science department, WSU. It focuses on tools for building abstract data types (using structure and class concepts in C++) and Object-Oriented Programming. We also begin the study of data structures in this course. For All CS 241 students, concurrent registration into CS 241 lab is a must.