Engineering Commons^™

Sensitivity Analysis For The Selection Of Linear Quadratic Regulator Weighing Parameters Q And R For Active Vibration Suppression Of A Cantilevered Beam, Steven L. Story

Theses and Dissertations

There has been much interest during the past decade to develop and launch large space structures. The high cost of launching material into orbit will require that these structures be assembled in space using light weight elements which are vulnerable to dynamic excitations. Active control may be necessary to rapidly attenuate large amplitude vibrations. The active vibration control system is usually designed after the structure has been optimized. The integrated design of the control system and the structure may provide additional weight savings. This thesis presents a sensitivity analysis of the structure/ control optimization problem. The structure used is an …

A Common Interface Real-Time Multiprocessor Operating System For Embedded Systems, Michael S. Rottman

Theses and Dissertations

Large real time applications such as aerospace avionics systems, battle management, and factory automation place many demands and constraints on the computing system not found in other applications. Software development is hindered by software dependence on the computer architecture and the lack of portability between systems. This thesis specifies and designs a real time multiprocessor operating system (RTMOS) that implements a consistent programming model, enabling the development of real time parallel software independent of the target architecture. The RTMOS defines the core functionality required to demonstrate the programming model. The RTMOS functional requirements are specified using Structured Analysis and Design …

An Environmentally Controlled Chamber For The Study Of Radon Detection, William R. Wharton Jr.

Theses and Dissertations

A system was developed to dynamically control and monitor the environment and radon concentration within a glovebox chamber for the study of radon. The system is designed around a personal computer workstation which automates the entire system. The radon concentration is determined by monitoring the count rate from radon and its progeny which are continuously circulated from the radon chamber through a Lucas Cell detection system. This information is then used as a base for controlling a radon injection system. When the concentration within the glovebox drops, the system injects a precisely-measured volume of high activity radon gas into the …

An Assessment Of The Accuracy Of Semi-Empirical Quantum Chemistry Calculations Of The Mechanical Properties Of Polymers, James R. Shoemaker

Theses and Dissertations

The ultimate mechanical properties of polymers, assuming perfect morphology, will be limited by the mechanical properties of a single, ideal polymer chain. Previous calculations of polymer chain moduli using semi- empirical (SE) quantum chemistry methods have resulted in modulus values much higher than experimentally measured. This study investigated the error in the calculated inherent to the method of calculation by comparing SE results for C-C bond potentials in two well characterized polymers, polyethylene and polydiacetylene. It was found that the SE calculation systematically overpredicted bond stiffness in these polymers by approximately 25% to 30%. This is the upper limit on …

Agility: Presentation And Flight Test Methods For The Operational Fighter Pilot, William R. Langdon

Theses and Dissertations

This thesis develops both metrics and flight test techniques to measure agility. During development of both the agility metrics and the flight test techniques, previous work conducted by the agility community and the Flight Test Center at Edwards Air Force Base was used as a lessons learned tool to insure favorable results. Both simulator and flight testing was performed to validate the flight test techniques. During simulator testing several problems with the original flight test techniques were noted. Flight testing on the pitch agility flight test technique solved most of its problems but problems found during roll testing in the …

Performance Of Guardrail End Treatments In Traffic Accidents, Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

The objective of this study was to report the results of the continued monitoring of the performance of guardrail end treatments in traffic accidents. This report includes an analysis of accidents involving the breakaway-cable-terminal (BCT), Kentucky's version of the median BCT (MBCT), Kentucky's weakened turned down (Type 7), the Crash Cushion Attenuating Terminal (CAT), and the Breakmaster System. The report includes data for 349 accidents. This includes 232 accidents involving a BCT, 66 accidents involving a MBCT, 37 accidents involving the Type 7 turned-down end treatment, 12 accidents involving the CAT, and 2 accidents involving the Breakmaster.

Considering all accidents, …

Dna Mapping Algorithms: Topological Mapping, Kenneth Moorman, Paul Poulosky, Will Gillett

All Computer Science and Engineering Research

There are several basic approaches that can be used in attempting to produce high-resolution DNA restriction maps. A standard approach is the match/merge approach in which first the topology of the map units being mapped together is suppressed and lists of potential matches between fragments are generated, and second the topology is introduced to eliminate matchlists which are inconsistent with the topology. This technical report documents a different approach to DNA mapping, known as topological mapping. In topological mapping the precedence of the two criteria are reversed, i.e., the topology of the two map units is used as the primary …

Bs News

Building Services Engineering

No abstract provided.

Identifiability In Wind Estimation From Scatterometer Measurements, David G. Long, Jerry M. Mendel

Faculty Publications

The problem of identifiability of a wind vector that is estimated from wind scatterometer measurements of the radar backscatter of the ocean's surface is addressed. The traditional wind estimation approach produces multiple estimates of the wind direction. A second processing step, known as dealiasing or ambiguity removal, is used to select a single wind estimate from these multiple solutions. Dealiasing is typically based on various ad hoc considerations. The traditional wind estimation approach results in multiple solutions associated with local minima in an objective function formed from the noisy backscatter measurements. The authors discuss the question of the uniqueness of …

Optimal Iterative Task Scheduling For Parallel Simulations, Joann M. Sartor

Theses and Dissertations

The ultimate purpose of this research is to reduce the time needed for execution of parallel computer simulations. In particular, the impact of task assignment strategies is determined for parallel VHDL circuit simulations. The classical scheduling problem, which assigns n precedence-constrained tasks to m processors is NP-complete in all but the simplest cases. The problem of assigning simulation tasks is further complicated by the iterative nature of computer simulations: each task is required to execute multiple times as the simulation executes. This investigation develops a polynomial-time algorithm (the level strategy) which provides optimal assignment for iterative systems with specific constraints. …

Construction, Calibration And Use Of A Neutron Time-Of-Flight Spectrometer, Charles L. Wood

Theses and Dissertations

The energy spectrum of a 5 curie Pu-Be neutron source is determined by use of a neutron time-of-flight spectrometer. This spectrometer measures the time it takes for a neutron to travel between two plastic scintillator detectors. Using a fixed distance for travel, a time spectrum is generated which is then unfolded into the energy spectrum of the source. The different aspects of equipment selection, connection and calibration of the system are described. With the resolved spectrum the energy resolution of the spectrometer is determined by using a Monte Carlo simulation of the experimental set-up. A dual- parameter experiment is conducted …

Development Of An Angular Distribution Function For The Study Of Atomic Lattice Structures Used In Atomistic Simulation, David Wesley

Theses and Dissertations

An angular distribution function (ADF) was developed as a tool to be used in atom simulation. The ADF lets us easily distinguish between different lattice structures for systems of atoms by looking at the distribution of bond angles. The ADF is also a useful tool for determining the amount of order in a system. First, model structures of simple cubic, FCC, BCC, and diamond were developed. Then, the ADF was used on these model structures so that a set of model graphs of the ADF could be used to compare to real systems. Finally, simulated systems of Ferric Titanate, Nickel …

Location And Routing Of The Defense Courier Service Aerial Network, Steven F. Baker

Theses and Dissertations

This study extends work done by the Military Airlift Command's Analysis Group on reducing the operating costs of the Defense Courier Service aerial network. The study's primary focus is to minimize those costs by varying the number and location of servicing depots, and the routes flown from those depots. The theoretical algorithm used in the methodology is an expansion of Laporte's (1986) formulation of the multiple depot multiple travelling salesmen facility-location problem. Multiple servicing frequency is addressed by clustering co-located demands with Kulkarni's (1985) subtour breaking constraint. Vehicle range is considered by redressing a shortfall of the subtour breaking constraint, …

Investigation Of A Zero-One Integer Programming Approach To Automating The Scheduling Process At The Usaf Test Pilot School, Lisa M. Hassel

Theses and Dissertations

This thesis investigated models that could be used to determine a feasible schedule for the Test Pilot School (TPS) training program and form the basis for an automated scheduling system. The TPS problem is formulated as a 0-1 integer linear program and is solved using preprocessing techniques and the Branch-and-Bound algorithm. The method produced feasible solutions for small problems that equate to portions of the TPS schedule but cannot efficiently solve large problems like the full TPS problem. More investigation should be conducted to alter the method developed in the study so it could be used for large problems. A …

Thermo-Mechanical Fatigue Of A Fiber Reinforced Titanium Aluminide Composite, Mark A. Bates

Theses and Dissertations

The thermo-mechanical fatigue behavior of a specific unidirectional fiber reinforced titanium aluminide composite was investigated. Three test specimens were subjected to in-phase thermo-mechanical cycling and four to out- of-phase thermo-mechanical cycling. The applied maximum mechanical stresses ranged from 500-800 MPa. The stress ratio of 0.1 was used for all tests. The temperature range was from 150-650 C and the resulting fatigue lives were in the 58-1487 cycles range. The out-of-phase test specimens failed sooner compared to their respective in-phase counterparts. In order to find out why, the test results were analyzed using a simple micromechanics analysis and compared. The fracture …

Development Of A Personal Computer Based Approach To Aircraft Parameter Identification, Mark S. Erickson

Theses and Dissertations

This thesis develops and tests a personal computer based approach to the aircraft parameter identification problem. The approach was tested analytically at the Air Force Institute of Technology, Wright-Patterson AFB, Ohio. These tests were conducted using simplified short period approximation and second-order transfer function models of longitudinal aircraft response. Initial evaluations were accomplished using simulated, noise free data. The longitudinal aircraft model was modified prior to flight test, for both convenience and necessity. This more complex model was evaluated during a flight test program at the USAFTPS, Edwards AFB, California. A T-38A aircraft was used as a tool to demonstrate …

The Self-Shielding Of Fallout Gamma Rays By Terrain Roughness, Mark S. Herte

Theses and Dissertations

The study presents a first order calculation of the self-shielding of nuclear weapon fission fragment gamma rays by surface roughness (microscopic terrain irregularities). To simulate fallout particles, polymer microspheres were deposited on slides containing samples of soil, concrete and asphalt roofing shingles. Scanning electron microscopy was used to photographically map the surfaces. The thickness of surface irregularities at various angles was measured by converting the photographs to digital images. Measurements showed a dependence upon the surface type, but not upon particle size. Average values of the measurements were modelled using a homogeneous buried source. With this geometry, dose rates were …

The Evolution Of The Wpi Advanced Space Design Program - An Evolving Program Of Technical And Social Analysis Using The Nasa Space Shuttle For Engineering Education, Fred J. Looft, Robert C. Labonte, William W. Durgin

Office of the Provost Scholarship

In December of 1982, Worcester Polytechnic Institute, with the cooperation and support of the MITRE Corporation, initiated a primarily undergraduate educational program to develop experiments to be flown onboard a NASA Space Shuttle. Christened the MITRE WPI Space Shuttle Program, it sponsored the development of five educationally meritorious experiments over a period of four years. Although the experiments were ready to fly in early 1986, the Challenger disaster delayed their flight until the Spring of 1991. The delay notwithstanding, the benefits of the first program were sufficient to justify the development of a second set of experiments. More comprehensive in …

Acuta Enews February 1991, Vol. 20, No. 2

ACUTA Newsletters

In This Issue

ACUTA gains new tax status

Stopping a runaway dialer

Just what is an engineer?

FCC ruling awaited

Party Line

In-house accounting

Ccfss News February 1991, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

The Synthesis Of Patterns Using A Series-Fed Array Of Annular Sector Radiating Line (Anserlin) Elements: Low-Profile, Circularly Polarized Radiators, James L. Drewniak, P. E. Mayes

Electrical and Computer Engineering Faculty Research & Creative Works

A series-fed, circularly polarized array of annular sector radiating-line elements that operates over a ground plane and has a low profile is presented. Pattern shaping can be achieved through control of the fraction of the incident power that is radiated by each element. This can be accomplished over a wide range by a simple adjustment in the geometry of each element. A synthesis technique is given, and experimental results are presented. The array is demonstrated to have a high return loss (good impedance match) and a low axial ratio

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, February 1991, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Quantum Network Theory Of Transport With Application To The Generalized Aharonov-Bohm Effect In Metals And Semiconductors, Cheng-Hsiao Wu, Gunter Mahler

Electrical and Computer Engineering Faculty Research & Creative Works

Quantum transport for resistor networks is developed with a general form factor, where each node point of the network is associated with a potential. The phase factor of the wave function in between two adjacent nodes is related to the reflection coefficient along that path. The exact transmission probability for a generalized Aharonov-Bohm ring is derived for a clean and cold crystal ring of arbitrary two-lead connections. The even- and odd-numbered rings have distinctly different transmission behaviors. The periodicity of the odd-numbered ring with respect to the threaded magnetic flux is shown to be double to that of an even-numbered …

Set-Valued Filtering And Smoothing, Wynn C. Stirling, Darryl Morrell

Faculty Publications

A theory of discrete-time optimal filtering and smoothing based on convex sets of probability distributions is presented. Rather than propagating a single conditional distribution as does conventional Bayesian estimation, a convex set of conditional distributions is evolved. For linear Gaussian systems, the convex set can be generated by a set of Gaussian distributions with equal covariance with means in a convex region of state space. The conventional point-valued Kalman filter is generated to a set-valued Kalman filter consisting of equations of evolution of a convex set of conditional means and a conditional covariance. The resulting estimator is an exact solution …

Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri

Chemical & Biomedical Engineering Faculty Publications

Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys.

Performance Evaluation Of A Traffic Control Mechanism For Atm Networks, Andreas D. Bovopoulos

All Computer Science and Engineering Research

Future ATM networks will be required to support a plethora of services, transaction types and cell sequence behaviors with performance guarantees. Before this goal can be realized, however, some basically problems related to bandwidth allocation and traffic control in the ATM layer must be resolve. Such problems will in all likelihood defy solution as long as they studied in isolation without a unifying traffic characterization and traffic control framework. This work presented in this paper is part of an ongoing effort directed at the development of an integrated traffic characterization and control infrastructure for ATM networks. In this paper a …

Saam: The Strategic Asset Allocation Model, Judy Lewis, Todd Gamble, John Tai

All Computer Science and Engineering Research

Asset Allocation has become a dominant factor for investment strategies in recent years. It has found that by holding a strategically diversified portfolio, a high total return on investments can be maintained while, at the same time, reducing portfolio volatility. With recent federal regulations mandating pension investment responsibilities, appropriate asset allocation has become more important than ever. SAAM is a software package specifically designed to be used as a tool to aid the investment professional in determining pension portfolio allocations. SAAM uses the expect system shell CLIPS, has a user-friendly interface, displays output graphically, and runs within the confines of …

Convex Bayes Decision Theory, Wynn C. Stirling, Darryl Morrell

Faculty Publications

The basic concepts of Levi's epistemic utility theory and credal convexity are presented. Epistemic utility, in addition to penalizing error as is done with traditional Bayesian decision methodology, permits a unit of informational value to be distributed among the hypotheses of a decision problem. Convex Bayes decision theory retains the conditioning structure of probability-based inference, but addresses many of the objections to Bayesian inference through relaxation of the requirement for numerically definite probabilities. The result is a decision methodology that stresses avoiding errors and seeks decisions that are likely to be highly informative as well as true. By relaxing the …

The Optimal Location Of Geodss Sensors In Canada, Pierre J. Forgues

Theses and Dissertations

This thesis studies the maximal coverage p-median and the set covering facility location problems as applied to the GEODSS location problem. The classical single-objective mathematical formulations of the p-median and set covering problems are converted into network-flow formulations and various solution methods are developed using a scaled-down version of the GEODSS problem. The next step is the introduction of a second criterion function into the problem. This second function consists of minimizing the sum of the variance in coverage at the selected locations. Research reveals the deficiencies of MOLP (multiobjective linear programming) techniques in generating the efficient frontier of an …

Performance Analysis Of The Ethernet Under Conditions Of Bursty Traffic, Tony Y. Mazraani, Gurudatta M. Parulkar

All Computer Science and Engineering Research

In this paper we present a simulation study of the Ethernet performance under conditions of bursty traffic. This study is motivated by two observations: Ethernet will continue to be a widely used Local Area Network (LAN), especially as an access LAN for future high speed internet (or Broadband ISDN); and future high speed applications can best be modeled as bursty sources. Bursty traffic in this study is specified using three parameters: peak bandwidth, average bandwidth, and burst factor. The simulation study shows that the inherent behavior of the Ethernet does not change with bursty traffic. That is, as long as …