Engineering Commons^™

An Object Oriented Simulation Of The C-17 Wingtip Vortices In The Airdrop Environment, Hans J. Petry

Theses and Dissertations

This thesis effort focuses on the development of an object-oriented simulation of C-17 personnel airdrop operations and provides a tool for risk assessment of jumper and wingtip vortex interaction. Using the initial modeling efforts of the Wright Laboratory, this model expands those efforts to include random aircraft, wind and jumper movement within the simulation using MODSIM III as its language. Once the model was built, verified, and calibrated, it helped perform a preliminary analysis of jumper risk with varying element spacing and no crosswind. The results of the simulation provided 15 data points with which linear and logistic regression provided …

Analysis Of A Methodology For Linear Programming Optimality Analysis, Chanseok Jeong

Theses and Dissertations

The methodology of Johnson, Baner, Moore, and Grant can be applied to large scale linear programming models. A methodology for optimality analysis of linear programs was developed to create metamodels using response surface methodology techniques such as experimental design and least squares regression. A metamodel consists of a simple equation which is able to predict the optimal objective function value of a linear program. What is needed is some large scale application of the techniques to verify how accurate they are. In the research, I plan to use the large scale LP model, STORM. I use the "Hot Start" idea …

Transportation Modeling Of Remote Radar Sites And Support Depots, Sonia E. Leach

Theses and Dissertations

The North Warning System (NWS), a joint program of the United States Air Force (USAF) and the Royal Canadian Air Force (RCAF), is responsible for the maintenance of 47 remote radar sites across northern Canada. NWS's current airlift operations, which support the radar maintenance activities, consist of both helicopters and fixed wing aircraft positioned at five support depots. This thesis considers whether a reconfiguration of these support depots and the assignment of radar sites to them can result in either an airlift or total cost savings for NWS. Mixed integer linear programming models were formulated to address the questions surrounding …

The Application Of Statistical Process Control To Departure Reliability Improvement, Liu W. Chieh

Theses and Dissertations

This research effort focuses on applying statistical process control (SPC) techniques to the departure reliability improvement process for Air Mobility Command, Mission Reliability Office. Basic SPC methods, including Pareto analysis, cause and effect diagrams, and control charts are determined to be effective tools for analyzing and assessing departure reliability. In addition, two more alternative measures of effectiveness for departure reliability are evaluated and compared using AMC's data. SPC methods are also shown to be useful in assessing in performance and in determining the reporting frequency for on-time performance information. Additional statistical analyses are conducted, including on-way analyses of variance, hypothesis …

Sensitivity Analysis Of A Combat Simulation Using Response Surface Methodology, William J. Berg

Theses and Dissertations

This thesis provides a methodology to analyze the sensitivity of a combat simulation relative to the capabilities of the modeled weapon systems. Response Surface Methodology (RSM) was the primary technique used for analysis. A ground battle scenario was developed with a commercial PC wargame Empire II: The Art of War(TM). In the computer verses computer mode, the wargame was transformed into a combat simulation'. A screening experiment was used to determine which of an original 23 weapon factors were actually significant to this scenario. After analyzing the remaining five factors, only three ended up as truly significant to the battle …

Modeling A Chemical Battlefield And The Resulting Effects In A Theater-Level Combat Model, Todd M. Gesling

Theses and Dissertations

This thesis describes the development of a methodology to model chemical weapons use in the Joint Staff's Joint Warfare Analysis Experimental Prototype (JWAEP) and to quantify the resulting effects. The methodology incorporates organic unit assets and theater-level chemical assets into JWAEP by using the three principles of nuclear, biological, and chemical defense (NBC) which reflect joint and Army doctrine, and combines them with the basic concepts already used in existing theater-level models. Other aspects of the problem include representing chemical 'packages' on the battlefield, determining attrition and time effects, adjusting unit effectiveness, determining chemical package intelligence acquisition procedures, identifying solution …

Acuta Enews February 1997, Vol.26, No. 2

ACUTA Newsletters

In This Issue

Call for Nominations for 1997-98

ACUTA Board of Directors

Effective Presentations

Board Report

Welcome New Members

Is It a Virus- Or a Hoax?

Vendor Liaison Committee

DC at a Glance

FCC Designates Wireless Spectrum for School

FCC Extends Campus Station License Terms

Coming Soon to Your IXC: 10XXX Changes

Optimizing Airborne Area Surveillance Asset Placement, Douglas E. Fuller

Theses and Dissertations

Currently there is no automated planning tool for the optimum positioning of USAF area surveillance assets for a theater level campaign. This research seeks to find the optimum or near optimum placement of the limited USAF airborne surveillance assets against a theater level target set. The problem of finding the optimum orbit points can be modeled as a classic maximal covering location problem (MCLP). Operational constraints on the placement of surveillance aircraft can be handled by preprocessing the potential orbit points to eliminate infeasible orbit points. Heavy emphasis is placed on preprocessing the data to reduce problem size and hence …

A Cost Impact Assessment Tool For Pfs Logistics Consulting, Angela P. Giddings

Theses and Dissertations

Response surface methodology (RSM) is used for optimality analysis of the cost parameters in mixed integer linear programming. This optimality analysis goes beyond traditional sensitivity and parametric analysis in allowing investigation of the optimal objective function value response over pre-specified ranges on multiple problem parameters. Design of experiments and least squares regression are used to indicate which cost parameters have the greatest impact on the optimal objective function value total cost-and to approximate the optimal total cost surface over the specified ranges on the parameters. The mixed integer linear programming problems of interest are the large-scale problems in supply chain …

Sensitivity Of Availability Estimates To Input Data Characterization, Darren P. Durkee

Theses and Dissertations

Reliability analysts are often faced with the challenge of characterizing the behavior of system components based on limited data. Any insight into which model input data is most significant and how much data is necessary to achieve desired accuracy requirements will improve the efficiency and cost effectiveness of the data collection and data characterization processes. This thesis assesses potential significant factors in the probabilistic characterization of component failure and repair behavior with respect to the effect on system availability estimates. Potential factors were screened for significance utilizing fractional. factorial and Plackett-Burman experimental designs for several system models developed using an …

Experiments In Aggregating Air Ordnance Effectiveness Data For The Tacwar Model, James E. Parker

Theses and Dissertations

An interactive MS Access&trademark; based application that aggregates the output of the SABSEL model for input into the TACWAR model is developed. The application was developed following efforts to create a functional approximation of the SABSEL data using neural networks, statistical networks, and traditional statistical techniques. These approximations were compared to a look-up table methodology on the basis of accuracy, (RMSE

Applying Tabu Heuristic To Wind Influenced, Minimum Risk And Maximum Expected Coverage Routes, Mark R. Sisson

Theses and Dissertations

The purpose of this thesis is to provide Air Combat Command a method for determining the number of predator unmanned aerial vehicles (UAVs) required to cover a pre-selected target. Extending previous research that employs reactive TABU search methods for deterministic vehicle routing problems, this thesis incorporates wind effects that can significantly alter the travel times for any given scenario. Additionally, it accounts for possible attrition by introducing minimum risk route and expected number of target covered to the objective function. The results of the TABU search and subsequent Monte-Carlo simulation: gives the number of predator's required to cover a target …

Measuring The Need For Manufacturing Flexibility And Evaluating Its Economic Benefits, Navin Karwande

Theses

Flexible systems are known of enabling organizations to take advantage of diversified products, low volume production items with short life-cycles. They also improve the ability to respond to market changes. Flexibility has thus become a strategic manufacturing need in recent years.

Because of the high initial capital outlay involved, the selection of the appropriate flexible solution has become a critical issue. This thesis proposes a methodology to determine the most cost effective and feasible flexibility strategy. A flexibility audit is developed to analyze and evaluate the changes taking place in a facility's environment. These changes and a measurement scheme is …

Design, Simulation And Fabrication Of A Mems In-Situ Contactless Sensor To Detect Plasma Induced Damage During Reactive Ion Etching, Subramanian Ganesh

Theses

The present trend in the semiconductor industry is towards submicron devices. An inevitable process technique in achieving this is by reactive ion etching of the polysilicon gate. During RIE, the gate oxide may get damaged due to several causes. One of the main causes of the damage is the non-uniformity of the plasma. It is reported that these plasma inconsistencies are mainly due to electrode design and that they create spatial plasma potential fluctuation. These fluctuations are reported to be in the range of 10-20 Volts. By providing an in-situ monitoring of the wafers, the reliability of the device could …

Acuta Enews January 1997, Vol.26, No. 1

ACUTA Newsletters

In This Issue

Do You Have a Voice Mail Handbook?

A Few Words of Advice

Board Report

ACUTA Journal: Second Issue Topics

Membership Committee

Reimbursing Personal Calls

Editorial Board Named

DC at a Glance

WCU on the Cutting Edge

Interstate Long Distance Tariffs Eliminated

Block it, again

Welcome New Members

Analytical Models For Vehicle/Gap Distribution On Automated Highway Systems, Jacob Tsao, Randolph W. Hall, Indrajit Chatterjee

Faculty Publications

Highway congestion has in recent years become a pervasive problem for urban and suburban areas alike. The concept of Automated Highway Systems is based on the belief that integration of sensing, communication, and control technologies into vehicles and highways can lead to a large improvement in capacity and safety without requiring a significant amount of additional highway right-of-way. A fundamental determinant of Automated Highway Systems capacity is the vehicle-following rule, the rule that governs the behavior of vehicles traveling along a common lane (e.g., the spacing between any two longitudinally adjacent vehicles). Vehicle following affects the longitudinal capacity (achievable flow …

As-Is Evaluation & Process Design Of The 17/18 Foot Refrigerator At General Electric In Decatur, Alabama, Yongke Thio, Nicole Hagood

Honors Capstone Projects and Theses

No abstract provided.

An Object-Based Evolutionary Algorithm For Solving Rectangular Piece Nesting Problems, Kanchitpol Ratanapan, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Nesting problems have been tackled by researchers using a vast number of algorithms in the past. Most of the algorithms, however, need to perform on a one-dimensional space. Therefore, the problem must be transformed into a one-dimensional space problem similar to the travelling salesman problem. Consequently, loss of solutions due to the dimensional reduction may occur. In this study, an object-based evolutionary algorithm for rectangular piece nesting problems is proposed. This methodology is created on truly two-dimensional space, allowing new mechanisms (i.e., individual representation, initialization, etc.) and new object-based genetic operators (i.e., hill-climbing, mutation, and recombination operators) to perform effectively …

Selecting The "Best" Using Data Envelopment Analysis, Timothy R. Anderson, Akin Uslu

Engineering and Technology Management Faculty Publications and Presentations

One of the most important strengths of Data Envelopment Analysis, (DEA), is that it allows almost complete freedom in the way that each decision making unit, (DMU), evaluates itself relative to its peers. This tends to result in many DMUs receiving a high efficiency score. Particularly when DEA is applied in a decision making context, it may be desirable to select a single option rather than determining the set of efficient alternatives in ranking efficient DMU or to Assist selecting a "best" DMU. Several extensions to DEA have been proposed and used. This paper examines, compares, and integrates a variety …

A New Model Of High Temperature Low Cycle Fatigue Life Prediction - Applicability With Low Alloy Steels, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Creep-fatigue data on low alloy steels were collected from National Research Institute for Metals (NRIM) Tokyo, Japan. These data were generated for lCr-Mo-V, 2.25Cr-Mo, and 9Cr-lMo steels under a wide range of test conditions. A new creep-fatigue life prediction method was developed and data compiled were assessed to examine the applicability of the new method. A brief review of the empirically based, phenomenological life prediction methods was presented where no method was found to be applicable universally to all the creep-fatigue data. The new model was developed within the viscosity concepts, in which the damage parameter was accounted for in …

Dwell Sensitivity Fatigue Behaviour Of High Temperature Materials, Tarun Goswami, G. R. Halford, D. W. Hoeppner

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The dwell sensitivity fatigue behavior of six high temperature materials is examined in this paper: two stainless steels, 304L and 304, two tantalum alloys, Τ- Ι 11 and ASTAR 811C, pure nickel Ni 201 and a single crystal nickel-base superalloy, PWA 1480. The stainless steel alloys were found to be tensile dwell sensitive; however, a saturation in dwell sensitivity was found with the increase in strain range for all materials examined. At lower strain ranges the dwell cycles were producing lower lives than at higher strains, as found in the case of AISI SS 304 and two tantalum based alloys, …

Review Of Pit Nucleation, Growth And Pitting Corrosion Fatigue Mechanisms, Tarun Goswami, D. W. Hoeppner

Biomedical, Industrial & Human Factors Engineering Faculty Publications

This paper presents a review of the state of the art developments in the pitting corrosion fatigue of aircraft structural materials. Mechanisms that govern the nucleation and growth of pitting and corrosion fatigue (CF) are briefly addressed. Some of the developments made in the author's laboratories in proposing the fretting induced pit nucleation and growth mechanisms, analysis of the hidden corrosion constituents in fuselage joints and pitting corrosion fatigue crack growth (PCFCG) model are elucidated. An epistemology of the topic is presented which will be of assistance to the community working in this area.

Artificial Neural Network Based Model For Computation Of Injection Mould Complexity, Rawin Raviwongse, Venkat Allada

Engineering Management and Systems Engineering Faculty Research & Creative Works

The cost of injection mould construction depends primarily on the mould complexity. The ability to estimate the mould complexity before releasing the final drawings for construction purposes will greatly help the designers to understand the implications of their design on cost. Mould complexity depends on several factors such as part geometry, parting line, materials, and number of cavities per mould. In most industries, the mould complexity evaluation is performed manually based on past experiences of mould makers. Faced with a shortage of experienced mould makers, there is a pressing need for development of computer-aided tools for mould complexity evaluation. In …

Self-Assessment Of Total Quality Management Programs, Hung Yi Wu, Henry Allen Wiebe, John Politi

Engineering Management and Systems Engineering Faculty Research & Creative Works

Total quality management (TQM) has been increasingly accepted as a management philosophy. Criteria such as those contained in the Malcolm Baldrige National Quality Award (MBNQA) often guide TQM implementation. However, reports indicate that fully assessing TQM efforts is difficult and hiring experts to help with this task is expensive. Using survey instruments is an attractive alternative to full-scale assessment. Despite the availability of many papers covering organizational performance assessment, few instruments specifically address TQM evaluation. Furthermore, none of the TQM assessment instruments has been subjected to rigorous validation; thus, only modest confidence can be placed in results obtained from their …

The Effects Of Human-Computer Communication Mode, Task Complexity, And Desire For Control On Performance And Discourse Organization In An Adaptive Task, Cristina Bubb-Lewis

Psychology Theses & Dissertations

The present study examined how different communication patterns affected task performance with an adaptive interface. A Wizard-of-Oz simulation (Gould, Conti, & Hovanyecz, 1983) was used to create the impression of a talking and listening computer that acted as a teammate to help participants interact with a computer application.

Four levels of communication mode were used which differed in the level of restriction placed on human-computer communication. In addition, participants completed two sets of tasks (simple and complex). Further, a personality trait, Desire for Control (DC), was measured and participants were split into high and low groups for analysis. Dependent measures …

Corrosion Fatigue Crack Growth Behavior Of Aircraft Materials, Tarun Goswami, D. W. Hoeppner

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The effects of test parameters on the corrosion fatigue crack growth behavior of structural materials have been examined in this paper. Test parameters such as stress ratio, frequency, hold time, temperature, pH level of the media, and other parameters are known to alter the corrosion fatigue crack growth rates in structural materials. Numerous laboratory test variables that affect the crack growth and/or corrosion growth rates, which in an operating environment of an aircraft are not characterized, are reviewed. A summary of such information may help determine the inspection intervals of the new and aged airplanes, perform the inspections, and develop …

Two Parallel Finite Queues With Simultaneous Services And Markovian Arrivals, Srinivas R. Chakravarthy, S. Thiagarajan

Industrial & Manufacturing Engineering Publications

In this paper, we consider a finite capacity single server queueing model with two buffers, A and B, of sizes K and N respectively. Messages arrive one at a time according to a Markovian arrival process. Messages that arrive at buffer A are of a different type from the messages that arrive at buffer B. Messages are processed according to the following rules: 1. When buffer A(B) has a message and buffer B(A) is empty, then one message from A(B) is processed by the server. 2. When both buffers, A and B, have messages, then two messages, one from A …

Short-Term Resource Scheduling With Ramp Constraints [Power Generation Scheduling], Chung-Li Tseng, Chao-An Li, A. J. Svoboda, R. B. Johnson

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper describes a Lagrangian relaxation-based method to solve the short-term resource scheduling (STRS) problem with ramp constraints. Instead of discretizing the generation levels, the ramp rate constraints are relaxed with the system demand constraints using Lagrange multipliers. Three kinds of ramp constraints, startup, operating and shutdown ramp constraints are considered. The proposed method has been applied to solve the hydro-thermal generation scheduling problem at PG&E. An example alone with numerical results is also presented

Asynchronous Distance Learning Technology: The Instructor's Perspective, Earl Alexander Evans

Masters Theses

"Advances in communications, computer technology and human-computer interfaces have enabled concurrent advances in Web-based education. A number of case studies concerning applications of Web-based education for both distance learning and on-campus programs have been published. Primarily, these studies have focused on individual assessments of the Web-based technologies. In addition, these published studies have generally highlighted the successes while little discussion about failed attempts has been presented in the literature.

In contrast, this thesis provides a broad-based assessment of applied Web technology for higher education. This research was conducted via a survey completed by twenty five university and college faculty from …

A Biologically Inspired Connectionist Architecture For Directing Attention To Salient Visual Field Objects, David Lee Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

In an attempt to incorporate basic visual attention abilities into existing artificial vision systems, a neural model of the bidirectional interactions within and between the brain regions believed to be involved in human visual attention has been developed. This model currently gives an artificial vision system the ability to attend to salient, or pop-out features and objects within the vision system''s field of view. After a review of the physiology of human visual attention, a network model of the aforementioned neural interactions is presented, followed by a demonstration of its performance.