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1991

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Articles 991 - 1020 of 1363

Full-Text Articles in Engineering

Effect Of Flange Restraint On Web Crippling Strength, Roger A. Laboube, Wei-Wen Yu, Bhavnesh H. Bhakta Mar 1991

Effect Of Flange Restraint On Web Crippling Strength, Roger A. Laboube, Wei-Wen Yu, Bhavnesh H. Bhakta

CCFSS Library (1939 - present)

INTRODUCTION The web crippling limit states equations given in the AISI Specification were primarily developed based on the results in which the flange was not attached to the support beams. This may not accurately represent field practice, since flanges are typically fastened by bolts or welds to their support beam. Due to these fasteners, the Specification equations may be underestimating the web crippling strength of the member. Therefore, a pilot study was proposed to study the behavior of webs, and the load carrying capacity of the webs with restrained flanges.

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The Calendar - March 1991, Nova University Mar 1991

The Calendar - March 1991, Nova University

The Calendar

No abstract provided.

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Pcbs And Related Compounds In Lake Hartwell, Alan W. Elzerman, Frank M. Dunnivant, Geoffrey G. Germann Mar 1991

Pcbs And Related Compounds In Lake Hartwell, Alan W. Elzerman, Frank M. Dunnivant, Geoffrey G. Germann

Publications

No abstract provided.

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Modifications To Mcnp, Version 3b: Incorporating A Variable Density Atmosphere. Addendum, David L. Monti, Kirk A. Mathews Mar 1991

Modifications To Mcnp, Version 3b: Incorporating A Variable Density Atmosphere. Addendum, David L. Monti, Kirk A. Mathews

AFIT Documents

MCNP version 3B was modified to incorporate a continuously variable density atmosphere. This was accomplished by representing the variation of air density as a function of altitude with a series of continuous piecewise exponential curves up to a maximum altitude of 1000 km. User-written subroutines and functions were written which incorporated these piecewise functions. These subroutines and functions were subsequently incorporated into a production version of MCNP. Several MCNP subroutines and files were modified in support of these modifications. This report discusses detailed information regarding the theoretical development of the variable density model, the user written subroutines and functions, the …

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Hiro Kurashina's Review Of William N. Morgan's Prehistoric Architecture In Micronesia, Hiro Kurashina Mar 1991

Hiro Kurashina's Review Of William N. Morgan's Prehistoric Architecture In Micronesia, Hiro Kurashina

Pacific Studies

No abstract provided.

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Curling Burley Tobacco From An Automated Harvesting System, Linus R. Walton, Larry G. Wells, James H. Casada Mar 1991

Curling Burley Tobacco From An Automated Harvesting System, Linus R. Walton, Larry G. Wells, James H. Casada

Biosystems and Agricultural Engineering Faculty Publications

If burley tobacco can be successfully cured at high density under waterproof covers in the field, a producer can expand production without the necessity of building new curing barns and can thereby more easily justify investment in the automated burley tobacco harvesting system (Wells et al., 1990a, b). Curing under waterproof covers in the field and curing on frames in the barn were evaluated over three curing seasons using two varieties (KY 14 and TN 86), two plant densities (32 and 43 plants/m2, 3 and 4 plants/ft2), position of tobacco on the frame (four levels ranging …

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Automobiles, Computers And Assault Rifles: The Value-Ladenness Of Technology And The Engineering Curriculum, Charles C. Adams Mar 1991

Automobiles, Computers And Assault Rifles: The Value-Ladenness Of Technology And The Engineering Curriculum, Charles C. Adams

Pro Rege

Charles Adams received the 1989 Mikol Award for this essay, which was originally presented to the North Midwest Section of the American Society for Engineering Education.

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A Navigation Reference System (Nrs) Using Global Positioning System (Gps) Aiding, Richard D. Stacey Mar 1991

A Navigation Reference System (Nrs) Using Global Positioning System (Gps) Aiding, Richard D. Stacey

Theses and Dissertations

To quantify the performance abilities of existing or proposed navigation systems, the U.S. Air Force has for the last several years compared the performance of the system under test to the performance of a baseline navigation system known as the Completely Integrated Reference Instrumentation System (CIRIS). CIRIS obtains a highly accurate navigation solution by combining the output from three major subsystems: inertial navigation system (INS) information, barometric altitude information, and range and range-rate data from ground transponders which have been precisely surveyed. Although the navigation solution produced by CIRIS is highly accurate, it will soon be inadequate as the standard …

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A Fully Coupled, Automated Formation Control System For Dissimilar Aircraft In Maneuvering Formation Flight, Paul R. Rohs Mar 1991

A Fully Coupled, Automated Formation Control System For Dissimilar Aircraft In Maneuvering Formation Flight, Paul R. Rohs

Theses and Dissertations

This study developed a fully automated formulation control system, capable of controlling a number of like or dissimilar aircraft in maneuvering formation flight. C-130 fixed wing aircraft and H-53 helicopters were modelled in various formulations and simulated through a mix of maneuvers. External formation guidance was assumed as a single data burst of nominal function guidance commands and separation distances for each wing aircraft in the formation. No communication was assumed between formation aircraft. Wing aircraft track lead aircraft maneuvering with an ideal on-board sensor, maneuvering to maintain relative position. It was determined that lead aircraft inputs must be attenuated …

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Green's Function Approach To The Atmospheric Albedo Neutron Transport Problem, Donald R. Culp Jr. Mar 1991

Green's Function Approach To The Atmospheric Albedo Neutron Transport Problem, Donald R. Culp Jr.

Theses and Dissertations

This study investigated the reflection of neutron radiation off of the earth's upper atmosphere, with the goal of generating a quick-running computer algorithm to estimate the albedo free field flux at any point above the atmosphere. This thesis involved analytic development in the construction of the algorithm and employed Monte Carlo simulation for generating the energy and angle distributions of the reflected radiation. The Green's function approach to modeling the neutron transport process involved approximating each energy bin of the source spectrum as a Dirac pulse in energy and summing the contribution from each source bin. The computer program integrates …

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Calculated Point Defect Properties Of The Intermetallic Compounds Nickel Titanium (Niti) And Iron Titanium (Feti), Russell T. Lutton Mar 1991

Calculated Point Defect Properties Of The Intermetallic Compounds Nickel Titanium (Niti) And Iron Titanium (Feti), Russell T. Lutton

Theses and Dissertations

Atomistic simulation with a modified version of the DYNAMO code was used to calculate the point defect properties of the intermetallic compounds nickel titanium and iron titanium. The calculated energies are believed to be experimentally accurate to within +/- 0.1 eV. Vacant Ni or Fe lattice sites were preferred and had energies of 6.356 eV for NiTi and 5.899 eV for FeTi. Removing a Ti atom resulted in a neighboring antisite defect caused by migration of a Ni or Fe atom into the vacant Ti site. These configurations had energies of 7.024 eV for NiTi and 6.336 eV for FeTi. …

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Mapping Efficient Numerical Methods To The Solution Of Multiple Objective Linear Programs, Michael A. Shields Mar 1991

Mapping Efficient Numerical Methods To The Solution Of Multiple Objective Linear Programs, Michael A. Shields

Theses and Dissertations

This investigation was initiated to increase the speed, accuracy and capacity of m-simplex algorithms for solving multiple objective linear programming problems. Specifically, improvements were sought through the application of general numerical techniques. It soon became apparent that the m- simplex algorithm, like the simplex algorithm, is heavily dependent upon the technology of solving related systems of linear equations. The numerical arguments for the application of LU triangular matrix factorization techniques to simplex computations are well known. OF special significance to m-simplex performance is the case of rank-k updates to basis factorizations. A stable and efficient LU approach to the rank-k …

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New Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For A Normal Distribution With Specified Parameters, Goksel Kahya Mar 1991

New Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For A Normal Distribution With Specified Parameters, Goksel Kahya

Theses and Dissertations

This thesis improves the powers of the Anderson-Darling and Cramer-von Mises goodness-of-fit tests using the mean rank and the median rank plotting positions. A Monte Carlo simulation of 5000 repetitions is used to generate the critical values from n =4 through n =80 for certain significance levels. An extensive power study is performed to compare the powers of the modified tests to the known tests for the uniform, the exponential, the double exponential, the lognormal, and the Weibull distributions. The power of the A-D tests modified by the median rank plotting and the mean rank plotting position are approximately 0.01% …

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A Goodness-Of-Fit Test For A Family Of Two Parameter Weibulls With Known Shape Using Minimum Distance Estimation Of Parameters, John S. Crown Mar 1991

A Goodness-Of-Fit Test For A Family Of Two Parameter Weibulls With Known Shape Using Minimum Distance Estimation Of Parameters, John S. Crown

Theses and Dissertations

This research is to produce a modified Anderson-Darling goodness of fit test for the Weibull distribution when the location parameter is found by minimum distance estimation, the shape parameter is assumed known, and the MLE is used for the scale parameter. The critical values for the Anderson-Darling test are generated via Monte Carlo simulation when both the Anderson-Darling and Cramer-Von Mises distance statistics are minimized. These critical values are then used for a power study. The Monte Carlo simulation used 5000 repetitions for sample sizes of 5,8,12,15,16,20 and 25 with the Weibull shape parameter of . 5(.5)4.0. The power study …

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Hardware Upgrade Of A Segmented Drum Assay System, Claude A. Irvine Mar 1991

Hardware Upgrade Of A Segmented Drum Assay System, Claude A. Irvine

Theses and Dissertations

This paper describes the conversion of a DEC PDP-11/05 computer system, previously used in Canberra's Model 2220B segmented gamma scanner, with an IBM PC. Two tasks necessary for completion of the project involved reestablishing communications with a Canberra Series 35+ multi-channel analyzer and a scan table controller. An additional serial/parallel card was installed in the PC to reinstate comunications with the multi-channel analyzer. For computer control of scan table controller operations a digital input/output card was used along with an external electromechanical relay board; when implemented together this hardware setup replaces functions that were normally processed through a motion control …

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The Development Of An Officer Training School Board Score Prediction Method Using A Multi-Board Approach, Sandra C. Niemi Mar 1991

The Development Of An Officer Training School Board Score Prediction Method Using A Multi-Board Approach, Sandra C. Niemi

Theses and Dissertations

One phase in the Officer Training School (OTS) selection process is meeting a selection board. Recruiting Services (HQ ATC/RS) currently uses a regression model (based on data from one board) to evenly distribute 'quality' among the different panels in the selection boards. HQ ATC/RS wanted a method of predicting board scores based on data from multiple boards. This study used the results from eighteen boards and 9215 applicants to develop and validate a multi-board regression model for each of five application categories. Comparisons between the two models showed mixed results. In two categories, non- rated operations and technical, the single-board …

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A Prototype Meta-Language And Automated Translator For Decision Analysis Problem Formulation, Jerry R. Puyear Mar 1991

A Prototype Meta-Language And Automated Translator For Decision Analysis Problem Formulation, Jerry R. Puyear

Theses and Dissertations

This thesis research effort develops a prototype meta-language for decision analysis problem description and automated software to translate the meta-language into a format useable by decision analysis software solvers. MELDA, the metalanguage developed, makes use of special symbols to provide a succinct language for the automation environment yet provides the means for user comprehension. Complete syntax and implementation rules are included. The MELADA translator software developed, DAT, stores the data given by MELADA in a file using prototype standard format, DASF, designed to hold all required data to solve a problem. DAT provides error checking and a message output file. …

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Locating Direction Finders In A Generalized Search And Rescue Network, Jean M. Steppe Mar 1991

Locating Direction Finders In A Generalized Search And Rescue Network, Jean M. Steppe

Theses and Dissertations

A multiobjective linear programming approach is applied to the problem of locating receiving stations and HFDF receivers in a search and rescue network in order to maximize the expected number of distress signals that are geolocated. The multiobjective formulation is made up of two contrasting objectives: one maximizes the expected accurate lines of bearing, and one minimizes the excess coverage in the network. The individual objectives are weighted and combined into a composite objective function. The resulting problem is expressed as a two-stage network flow problem and is solved using SAS LP with a limited number of binary variables. The …

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An Interactive Life Cycle Cost Forecasting Tool, John A. Gibson Iv Mar 1991

An Interactive Life Cycle Cost Forecasting Tool, John A. Gibson Iv

Theses and Dissertations

Enhancements were applied to an existing tool designed to estimate life cycle costs. These enhancements provide greater ease of data manipulation, additional options in developing models, and the ability to make modifications to suit the needs of the user. Life cycle costs can be generated quickly and easily. Analysis proved the amount of work done by the computer could be reduced with no loss of information. Additionally, the paths available to the user are shown graphically through flow charts--aiding in the learning process. The efforts of the user can now be directed towards developing models instead of spending those efforts …

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Enhancements To Pcrsm, Laurie M. Rouillard Mar 1991

Enhancements To Pcrsm, Laurie M. Rouillard

Theses and Dissertations

The purpose of this study was to enhance the capability of PCRSM, a personal computer based decisions support system, to perform response surface methodology. PCRSM was enhanced to allow the printing of graphical displays such as residual plots and to provide the capability to decode the regression equation back to the original variables. Reverse documentation of the prototype was also developed to describe the interfacing of the individual executable modules and development environment. Response surface methodology is a group of statistical tools used to analyze the relationships between predictors (input variables) and responses (output variables).

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Saber: A Theater Level Wargame, William F. Mann Iii Mar 1991

Saber: A Theater Level Wargame, William F. Mann Iii

Theses and Dissertations

This thesis provides a foundation to build a new theater level computerized wargame for the Air Force Wargaming Center, Maxwell AFB, AL to replace the Theater War Exercise (TWX), also known as Agile. Given a recently developed land battle, this thesis' effort links US Air Force doctrine with a conceptual model's framework and designs a new air battle module. The integration of both the air and land battles forms a new game, Saber. This thesis redefines the ground combat units of the land battle, and adds theater air defense units, bases and aircraft packages. This thesis introduces stochastic attrition between …

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Analysis Of The Effects Of The Commander's Battle Positioning On Unit Combat Performance, Thomas I. Pratt Mar 1991

Analysis Of The Effects Of The Commander's Battle Positioning On Unit Combat Performance, Thomas I. Pratt

Theses and Dissertations

The purpose of this study was to determine the effect of the Commander's battle positioning on unit combat performance. Research was focused on analyzing the location of the Battalion/Task Force Commander during daytime deliberate attacks conducted at the U.S. Army's National Training Center, Fort Irwin, CA. Forty battles, from January 1986 to September 1989, provided the basis for this study. Information that described the Commander's location, a general description of the battle, and unit measures of effectiveness, was collected for each battle and put in a format that allowed for ease of analysis. This study database was explored using numerous …

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A Network Flow And Goal Programming Approach To Modeling The Impact Of Pre-Accession Training To The Trained Personnel Requirements Process, William J. Beveridge Mar 1991

A Network Flow And Goal Programming Approach To Modeling The Impact Of Pre-Accession Training To The Trained Personnel Requirements Process, William J. Beveridge

Theses and Dissertations

HQ ATC was tasked to analyze the impact of pre-accession training to the Trained Personnel Required (TPR) and training production process. Pre- accession training is a policy of providing contracted initial skills training to enlistees prior to entering basic military training. The purpose of this study was to develop a method to model the impact of pre-accession training. A network modeling and goal programming approach was used. Comparisons between the current training policy and a pre-accession training policy were made. Sensitivity was conducted on the impact of a balk rate on the new policy. The balk rate is the percent …

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A Study Of Variables To Help Predict Navigator Training Success And Classification, Gary A. Hagler Mar 1991

A Study Of Variables To Help Predict Navigator Training Success And Classification, Gary A. Hagler

Theses and Dissertations

This study attempted to build statistical models which could possibly be used to help predict an individual's final outcome of pass or fail from Undergraduate Navigator Training (UNT). Also, the research tried to develop models to help place a potential trainee into one of the three training tracks at UNT. The variables studied were test scores from a computerized testing device which measured psychomotor and cognitive skills of individuals entering training. The Air Force Officers Qualifying Test (AFOQT) scores were also variables considered. Data was from 317 trainees from the years 1988 to 1990. Discriminant analysis was applied in an …

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A Solution Methodology For The Variable-Level Scheduling Problem, Dennis R. Benson Mar 1991

A Solution Methodology For The Variable-Level Scheduling Problem, Dennis R. Benson

Theses and Dissertations

This study looked at a specific scheduling problem for a Department of Defense agency. A heuristic algorithms was developed to solve a general variable-level scheduling problem and was applied to this specific problem. This heuristic used linear programming and integer programming to find the minimum number of weekly billable hours for five alternative schedules. The best alternative schedule was further developed into a spreadsheet designed, squad level, master schedule. The result of this study was a proposed schedule that would save the United States government 8.2% of their security costs for this one part of the governmental agency. These savings …

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The Utility Of Elliptical And Circular Confidence Regions For Hfdf Receivers, Paul T. Nemec Mar 1991

The Utility Of Elliptical And Circular Confidence Regions For Hfdf Receivers, Paul T. Nemec

Theses and Dissertations

This thesis investigates HFDF confidence region (CR) shape exhibited by geolocations in a search-and-rescue context. In Phase I, a Keeney-Raiffa multiattribute utility function was developed which allowed an analytical measure of preference between elliptical and equivalent- probability circular CRs. Phase II utilized a likelihood approach to establish CR shape for sample operational geolocations having multiple points of bearing intersections. For 12 sample Phase I geolocations, the elliptical CR always had higher utility than its corresponding circular CR. For accepted sample geolocations, a preference condition was developed whereby a circular CR would only be preferred over the corresponding elliptical CR if …

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Multicriteria Network Routing Of Tactical Aircraft In A Threat Radar Environment, Ernst K. Isensee Mar 1991

Multicriteria Network Routing Of Tactical Aircraft In A Threat Radar Environment, Ernst K. Isensee

Theses and Dissertations

Real-time route planning for tactical aircraft has established a requirement for analytical tools which prescribe optimal solutions. The Air Force Electronic Warfare Center has developed a computerized routing aid which enhances the ability to plan tactical flight missions under real-time constraints. The decision aid known as the Improved Many-on-Many (IMOM) allows the user to subjectively evaluate flight routes within enemy radar coverages. However, the mission planner is required to intuitively assesses the survivability risks associated for each user defined route. As an alternative to this method, the deterministic procedures of dynamic programming and the shortest path algorithms offer techniques which …

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Incorporating Value Systems In Strategic Force Analysis, Nancy D. Snyder Mar 1991

Incorporating Value Systems In Strategic Force Analysis, Nancy D. Snyder

Theses and Dissertations

Deterring potential Soviet aggression depends on our ability to hold at risk those assets they value most. This research investigates target valuation as an added dimension to force structure analysis. An extensive literature review is followed by the development and demonstration of a methodology defining development and use target values. The literature review covers arms control concepts to give a foundation for an important use of force structure analysis. It also covers measures of effectiveness. The final part of the review is comprised of definitions of perspectives on nuclear war. The methodology defines motivations for force structuring in the form …

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Effects Of Colocation And Non-Colocation Of Sensors And Actuators On Flexible Structures, W. C. Lee Mar 1991

Effects Of Colocation And Non-Colocation Of Sensors And Actuators On Flexible Structures, W. C. Lee

Theses and Dissertations

This thesis compares the performance and robustness of colocated and non-colocated sensor/actuator pairs. Linear quadratic Gaussian and loop transfer recovery (LOG/LTR) procedures are used to design optimum controllers for three example problems. The first example is a single motion degree-of-freedom system having motion only about one axis. This type of system does not have any right half plane zeros for the non-colocated case; however, the thesis shows it behaves as a non minimum phase system. The second example is a Bernoulli-Euler beam which does not have RHP zeros. An optimum LOG/LTR controller can not improve the robustness of non minimum …

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A Prolog-Based System For Hardware Verification, Kevin L. Sparks Mar 1991

A Prolog-Based System For Hardware Verification, Kevin L. Sparks

Theses and Dissertations

With the expanding number of components provided on a single digital chip, verification of digital designs is becoming a major problem. The more circuits one places on a single chip, the greater the number of input/output combinations which need to be checked. A paper by Barrow in 1984 discusses a Prolog-based hierarchical formal verification system which he calls VERIFY. Barrow provided a lot of information on what VERIFY can and cannot do, and on projected enhancements. He does not, however, mention how VERIFY actually performs the task of formal verification. This thesis will provide a description of one possible implementation …

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