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Articles 1111 - 1140 of 1284

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

How Effective Has The Air Force Been In Eliminating Its Dependence On Ozone Depleting Chemicals?, L. Susan Willard Sep 1994

How Effective Has The Air Force Been In Eliminating Its Dependence On Ozone Depleting Chemicals?, L. Susan Willard

Theses and Dissertations

This research was undertaken to determine how effectively the Air Force had eliminated its dependence on Ozone Depleting Chemicals. The research was limited to analyzing the impact of ODCs on major acquisition programs. Results indicated existing variables which may be impeding full implementation. Also identified were lessons learned which could be applied to future environmental legislation with potential impact on acquisition programs. In- depth telephonic interviews were conducted with Program Directors responsible for the development and fielding of major Air Force acquisition programs. Analysis revealed that ODCs substantially impacted the acquisition programs to the extent that many programs had classified …

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Dynamic Load Balancing For A Parallel Discrete-Event Battlefield Simulation, Seth R. Guanu Jun 1994

Dynamic Load Balancing For A Parallel Discrete-Event Battlefield Simulation, Seth R. Guanu

Theses and Dissertations

This thesis investigates issues involved in developing a dynamic load balancing model for a parallel discrete event battlefield simulation. The research covers issues in task management, discrete-event simulation, parallel simulation, and load balancing. There are four primary issues discussed concerning the design of a dynamic load balancing model. The first issue is processor load evaluation which deals with the calculation of the amount of work on a processor. The second issue is load balancing profitability determination which deals with the decision to load balance or not based on some cost-gain relationship. The third issue is task migration which deals with …

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Embedded Chaotic Time Series: Applications In Prediction And Spatio-Temporal Classification, James R. Stright Jun 1994

Embedded Chaotic Time Series: Applications In Prediction And Spatio-Temporal Classification, James R. Stright

Theses and Dissertations

The Deterministic Versus Stochastic algorithm developed by Martin Casdagli is modified to produce two new, methodologies, each of which selectively uses embedding space nearest neighbors. Neighbors which are considered prediction relevant are retained for local linear prediction, while those which are considered likely to represent noise are ignored. For many time series, it is shown possible to improve on local linear prediction with both of the new algorithms. Furthermore, the theory of embedology is applied to determine a length of test sequence sufficient for accurate classification of moving objects. Sequentially recorded feature vectors of a moving object form a training …

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Analysis Of Thunder Combat Simulation Model, Timothy S. Webb Mar 1994

Analysis Of Thunder Combat Simulation Model, Timothy S. Webb

Theses and Dissertations

TAC THUNDER, or THUNDER, is a two-sided large scale computer simulation model that simulates air and ground combat, logistics, and limited airlift at the theater level. It is in use by several allied nations, major defense contractors, and various Department of Defense DoD analysis agencies. The objectives of this thesis effort were to examine the overall model variability, examine the model output for possible interrelationships, and examine the model sensitivity to input parameters. A univariate and multivariate analysis was performed to examine the first two objectives. The univariate analysis consisted of an analysis of the confidence intervals and replication requirements …

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An Analysis Of Stopping Criteria In Artificial Neural Networks, Bruce Kostal Mar 1994

An Analysis Of Stopping Criteria In Artificial Neural Networks, Bruce Kostal

Theses and Dissertations

The goal of this study was to decide when to terminate training of an artificial neural network ANN. In pursuit of this goal, several characteristics of the ANN were monitored throughout ANN training classification error rate of the training set, testing set, or a weighted average of the two moving average classification error rate measurements of the difference between ANN output and desired output error sum of squares, total absolute error. or largest absolute error or ANN weight changes absolute weight change, squared weight change, or relative weight change. Throughout this research, the learning rate was held constant at 0.35. …

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An Analysis Of Air Force Acquisition Engineering Officer's Perceptions Of The Adequacy Of Their Preparation For Management, Steven E. Woodruff Mar 1994

An Analysis Of Air Force Acquisition Engineering Officer's Perceptions Of The Adequacy Of Their Preparation For Management, Steven E. Woodruff

Theses and Dissertations

The purpose of this study was to determine how much time Air Force acquisition engineers spend in performing management functions, how those engineers spend in performing management functions, how those engineers perceive their management training, and which types of training contribute the most to managerial competency. The results from surveys of 215 acquisition engineers assigned to ASCEN, Wright-Patterson AFB, OH and their supervisors revealed that engineers do indeed spend substantial amounts of time performing management functions. Slightly more than half the engineers reported spending at least 50 of an average workday performing management functions. Over 53 of engineers responding to …

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A Mean Value Analysis Heuristic For Analysis Of Aircraft Sortie Generation, Richard C. Jenkins Mar 1994

A Mean Value Analysis Heuristic For Analysis Of Aircraft Sortie Generation, Richard C. Jenkins

Theses and Dissertations

The primary objective of this study was to develop an analytical methodology based on the Mean Value Analysis algorithm that approximates the performance characteristics of a queueing network model QNM containing a fork- join queue with probabilistic branching. These performance characteristics are response time, throughput and queue length at each station. The QNM solved contains the essential features of the aircraft sortie generation process. The sensitivity of the methods accuracy to increases in server utilization was determined. The comparisons of the results of the MVA heuristic to the outputs of the Logistics Composite Model LCOM simulation indicate that the heuristics …

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A Simulation Approach To Granite Sentry System Analysis, Marilyn J. Bauer Mar 1994

A Simulation Approach To Granite Sentry System Analysis, Marilyn J. Bauer

Theses and Dissertations

This study demonstrated the use of simulation modelling to analyze Granite Sentry system performance. The availability simulation model constructed provides a number of system performance measures as a function of component MTBFs and MTTRs. Analysis of failure data prior to model construction supported the generally accepted use of exponentially distributed failure rates and lognormally distributed repair times.

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Proactive Monitoring Of Performance In Stochastic Communication Networks, John C. C. Van Hove Mar 1994

Proactive Monitoring Of Performance In Stochastic Communication Networks, John C. C. Van Hove

Theses and Dissertations

This research proposes several models for placing bounds on the expected values of some dynamic performance measures for computer communication networks with failing components. These models provide an understanding of expected network performance that is useful in the process of proactive performance monitoring and also in defining level of service agreements with network users. There were three objectives for this research. The first objective was to extend some existing models of steady-state stochastic network performance to a dynamic network flow representation in order to capture the dynamic nature of proactive monitoring. The second objective was to convert the extended absolute …

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An Investigation Of Simulated Annealing Applied To Structural Optimization Problems, Richard C. Mceachin Mar 1994

An Investigation Of Simulated Annealing Applied To Structural Optimization Problems, Richard C. Mceachin

Theses and Dissertations

This thesis investigates the feasibility of using Simulated Annealing SA in structural optimization problems. The investigation involves solving benchmark structural optimization problems with an SA algorithm, and comparing its solutions to those found by four other optimizers. Overall, the analysis shows that SA has limited applicability in structural optimization. Two primary factors were found to adversely impact the performance of the SA algorithm in these problems. These factors are high dimensionality, and high levels of constraint. The difficulty involved in solving these problems with a random search increases exponentially with the number of dimensions. The number, and non-linearity, of the …

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Application Of Sequential Quadratic Programming To Large-Scale Structural Design Problems, Mark A. Abramson Mar 1994

Application Of Sequential Quadratic Programming To Large-Scale Structural Design Problems, Mark A. Abramson

Theses and Dissertations

Large-scale structural optimization problems are often difficult to solve with reasonable efficiency and accuracy. Such problems are often characterized by constraint functions which are not explicitly defined. Constraint and gradient functions are usually expensive to evaluate. An optimization approach which uses the NLPQL sequential quadratic programming algorithm of Schittkowski, integrated with the Automated Structural Optimization System ASTROS is tested. The traditional solution approach involves the formulation and solution of an explicitly defined approximate problem during each iteration. This approach is replaced by a simpler approach in which the approximate problem is eliminated. In the simpler approach, each finite element analysis …

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The Effective Use Of Animation In Simulation Model Validation, Christopher L. Swider Mar 1994

The Effective Use Of Animation In Simulation Model Validation, Christopher L. Swider

Theses and Dissertations

This study examined two animation displays moving icons, bar graphs at two presentation speeds to determine how each of these factors affected the animations ability to communicate violations of model assumptions. Subjects viewed animation displays individually and in combination at each presentation speed. Eight problem scenarios were presented to evaluate each animations ability to communicate violations of different assumptions. Each animations communication ability was measured subjectively and objectively. Subjective measures in the form of pairwise comparisons were used to calculate normalized preference ratings for each animation. objective measures included problem identification accuracy and problem time. Subjective results indicated that moving …

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An Rsm Study Of The Effects Of Simulation Work And Metamodel Specification On The Statistical Quality Of Metamodel Estimates, Michael K. Taylor Mar 1994

An Rsm Study Of The Effects Of Simulation Work And Metamodel Specification On The Statistical Quality Of Metamodel Estimates, Michael K. Taylor

Theses and Dissertations

This research investigated the combined influence of simulation work and metamodel specification on the statistical quality of the estimates obtained from the resulting metamodels of the simulation data. A 9 x 2 x 2 experiment consisting of 9 cases of simulation work, 2 levels of metamodel specification, and 2 levels of design fractionation were designed for 8 different configurations of MMk queues. The only observed statistic for this experiment was the average queue length. Simulation estimates for each configurations average queue length were calculated directly from the simulation data. In addition, the metamodels were fit to the simulation data and …

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An Integer Solution Heuristic For The Arsenal Exchange Model (Aem), Daniel J. Green Mar 1994

An Integer Solution Heuristic For The Arsenal Exchange Model (Aem), Daniel J. Green

Theses and Dissertations

The Air Force Studies and Analyses Agency sought a method for converting the continuous solution produced by the Arsenal Exchange Model into a feasible integer solution. The current integerization method leaves weapons unused and targets uncovered and could be improved. In the method developed, the noninteger valued variables in the continuous solution are rounded down to the nearest integer to produce a truncated solution. An integer goal program is then used to reallocate the weapons and targets made available in the rounding process. The truncated solution is then combined with the solution of the integer goal program to produce a …

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An Air Mission Planning Algorithm For A Theater Level Combat Model, Brian J. Griggs Mar 1994

An Air Mission Planning Algorithm For A Theater Level Combat Model, Brian J. Griggs

Theses and Dissertations

This thesis describes the development of an air mission planning algorithm for the Joint Staffs Future Theater Level Model FTLM. The overall problem scope was to develop an algorithm to handle major factors bearing on the combat mission planning problem while providing hook-ups for the FTLM architecture. Other aspects of the problem included finding the appropriate level of detail, developing a fast solving technique, and attempting to use existing data. The problem was handled by using some ideas from existing aircraft allocation algorithms and by adding some new techniques. The proposed air mission planning algorithm supplies the optimum degree of …

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Assessing The Vulnerability Of Multi-Commodity Networks With Failing Components, Alan R. Robinson Mar 1994

Assessing The Vulnerability Of Multi-Commodity Networks With Failing Components, Alan R. Robinson

Theses and Dissertations

This research proposes an analytical approach for assessing flow disturbance, or compromise, based on limited sampling of arc flow information in multi-commodity, or multiple origin-destination O-D, networks with failing arcs. There were three objectives established for this research. The first objective was to bound the expected flow, given the arcs fail with certain probabilities, which was accomplished by reviewing current approaches for single-commodity networks and extending the results to the multi-commodity case. The second objective was to determine the best placement of flow monitors to obtain the most accurate estimates of O-D pair volumes. This was accomplished using a multi-criteria …

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A Fortran Based Learning System Using Multilayer Back-Propagation Neural Network Techniques, Gregory L. Reinhart Mar 1994

A Fortran Based Learning System Using Multilayer Back-Propagation Neural Network Techniques, Gregory L. Reinhart

Theses and Dissertations

An interactive computer system which allows the researcher to build an optimal neural network structure quickly, is developed and validated. This system assumes a single hidden layer perceptron structure and uses the back- propagation training technique. The software enables the researcher to quickly define a neural network structure, train the neural network, interrupt training at any point to analyze the status of the current network, re-start training at the interrupted point if desired, and analyze the final network using two- dimensional graphs, three-dimensional graphs, confusion matrices and saliency metrics. A technique for training, testing, and validating various network structures and …

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Automating Satellite Range Scheduling, S. Michael Schalck Dec 1993

Automating Satellite Range Scheduling, S. Michael Schalck

Theses and Dissertations

The objective of this study was to develop a computer based satellite range scheduling SRS algorithm to create a 24 hour satellite support schedule. The algorithms goal was to schedule as many satellite support requests as possible. An iterative heuristic approach was used to schedule satellite support requests in three successive sub problems. The first sub problem involves scheduling low altitude satellite support requests using a mixed integer programming approach. The next two sub problems each involve scheduling 12 hour blocks of medium and high altitude satellite support requests, again using a mixed integer programming approach. Fourteen 24 hour schedules …

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An Evaluation Of The Software Engineering Institute's Capability Maturity Model As A Framework For Software Process Improvement At Three Air Logistics Centers, Brian G. Hermann, Raymond J. Lewis Jr. Dec 1993

An Evaluation Of The Software Engineering Institute's Capability Maturity Model As A Framework For Software Process Improvement At Three Air Logistics Centers, Brian G. Hermann, Raymond J. Lewis Jr.

Theses and Dissertations

This research sought to determine whether a relationship exists between the maturity level of the software process, as determined by the Software Engineering Institutes Capability Maturity Model SEI CMM, and the actual success of particular software projects at three US Air Force Air Logistics Centers. Project success is defined in terms of cost, schedule, and quality criteria. In addition, each organizations acceptance of the SEI assessment as well as its effectiveness in setting up follow-on process improvement programs were evaluated. Finally, the process improvement programs were reviewed individually inasmuch as these programs are the mechanisms for achieving improved quality, lower …

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Measuring User Satisfaction Of The Electronic Mail System At Air Force Materiel Command Headquarters As An Indicator Of The System's Effectiveness, Randall R. Bradford Dec 1993

Measuring User Satisfaction Of The Electronic Mail System At Air Force Materiel Command Headquarters As An Indicator Of The System's Effectiveness, Randall R. Bradford

Theses and Dissertations

The purpose of this study was to evaluate the effectiveness of the electronic mail system at the Air Force Materiel Command Headquarters. User satisfaction was measured as an indicator of the systems effectiveness. In order to provide an objective measurement of system effectiveness, the following research questions were addressed: (1) What is system effectiveness in relation to this particular electronic mail system, and how should it be measured? (2) What measurement instruments can be adapted, modified, or created to measure effectiveness as it is defined for problem? (3) If a measurement instrument is administered what do the results of the …

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Synthetic Battlebridge: Information Visualization And User Interface Design Applications In A Large Virtual Reality Environment, Kirk G. Wilson Dec 1993

Synthetic Battlebridge: Information Visualization And User Interface Design Applications In A Large Virtual Reality Environment, Kirk G. Wilson

Theses and Dissertations

With shrinking budgets and fewer personnel, future military training will rely heavily on simulated environments. The goal for this training is to reduce cost while maintaining readiness and unparalleled capability for all levels of military command. This thesis effort, the Synthetic Battle Bridge SBB , provides a real-time simulated environment for military commanders to observe on-going computer simulations of varying participation levels and helps them wring the most from a simulation. The SBB, designed for higher ranking personnel with little time to spend learning how to run the system, must exhibit three capabilities ease-of-use, long-term retention, and adaptability. Based on …

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Guidelines For Ensuring Software Supportability In Systems Developed Under The Integrated Weapon System Management Concept, Forrest F. Butts Iii, Anthony C. Johndro Dec 1993

Guidelines For Ensuring Software Supportability In Systems Developed Under The Integrated Weapon System Management Concept, Forrest F. Butts Iii, Anthony C. Johndro

Theses and Dissertations

This thesis studied the software maintenance planning and practices of the pilot Integrated Weapon System Management IWSM programs. Before IWSM, a System Program Office SPO acquired an Air Force weapon system then passed it to an Air Logistics Center ALC for follow-on support. The ALC was forced to maintain the software despite its questionable maintainability. The SPO de- emphasized maintainability because maintenance was an ALC responsibility and building maintainable software increased development costs and lengthened schedules. The IWSM philosophy closes the gap between development and maintenance. A System Program Director SPD, who oversees both system development and maintenance, has an …

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Integration And Enhancement Of The Saber Wargame, Karl S. Mathias Dec 1993

Integration And Enhancement Of The Saber Wargame, Karl S. Mathias

Theses and Dissertations

The Saber wargame is a theater-level air/land battle wargame written in Ada that is being developed for the Air Force Wargaming Center at Maxwell AFB, AL. This thesis documents how the user interface and simulation engine were integrated. Integration was accomplished by developing a portable object-oriented database system (OODBMS) interface. The interface was implemented in Ada and tied to an OODBMS also written in Ada. Using the interface, both subsystems were able to work from a consistent database and exchange information. The user interface was enhanced by converting it from the Software Technology for Adaptable Reliable Systems Ada/X Window System …

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The Application Of Simulated Annealing To Stochastic Systems, Charles B. Warrender Nov 1993

The Application Of Simulated Annealing To Stochastic Systems, Charles B. Warrender

Theses and Dissertations

Simulated Annealing was used to optimize three constrained simulation models. For each of these models, seven different acceptance functions were evaluated and compared against the performance of Local Search. These comparisons demonstrated the affect that different acceptance functions have on the performance of the algorithm. The performance was measured by the average solution quality and average efficiency obtained from several runs. The first model facilitated the implementation of Simulated Annealing using the SLAM simulation language. The configuration space was small, described by only two decision variables. It demonstrated the viability of using Simulated Annealing to optimize the variable settings in …

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An Investigation Of Integrated Product Development Implementation Issues: A Case Study Of Bosma Machine And Tool Corp, F. Paul Khuri, Howard M. Plevyak Jr. Sep 1993

An Investigation Of Integrated Product Development Implementation Issues: A Case Study Of Bosma Machine And Tool Corp, F. Paul Khuri, Howard M. Plevyak Jr.

Theses and Dissertations

This thesis investigated Integrated Product Development (IPD) implementation issues. Research emphasis focused on teams used in IPD, particularly self-directed work teams (SDWTs). The areas addressed in the study were: Work Environment, Team Organization, Training and Education, Group Dynamics and Communication, Motivation, Rewards and Incentives, Measurements, and Contracts. Data was collected using interviews and presented as a case study. The most significant findings on work environment were that the organization's leadership should commit to the teaming idea and sell it to the organization's members. Teams should be organized by choosing members carefully and defining all roles. Personnel should be trained in …

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Software Cost Estimating Models: A Comparative Study Of What The Models Estimate, George A. Coggins, Roy C. Russell Sep 1993

Software Cost Estimating Models: A Comparative Study Of What The Models Estimate, George A. Coggins, Roy C. Russell

Theses and Dissertations

This effort developed a consolidated document which highlights and examines differences in definitions, assumptions, and methodologies used by the REVIC, SASET, PRICES, and SEER-SEM cost models. The following research questions were investigated: (1) What differences exist between the cost models? (2) How do these differences impact the resulting estimates? (3) To what degree can we explain and adjust for known differences between the cost models? Seven specific areas were addressed: (1) software development phases, (2) development activities and cost elements, (3) source lines of code and language differences, (4) key model attributes and key cost drivers, (5) implications of Project …

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Pollution Prevention Incentives For Major Weapon System Programs, Donna C. Heinz, Dudley C. Wireman Sep 1993

Pollution Prevention Incentives For Major Weapon System Programs, Donna C. Heinz, Dudley C. Wireman

Theses and Dissertations

This research was undertaken to identify positive incentives that would motivate both government personnel and contractors to incorporate pollution prevention into the early design phases of weapon system acquisitions. The adoption and implementation of such incentives would allow the Air Force to reach pollution prevention objectives more efficiently. A literature search revealed little information on the pollution prevention program in the military. In contrast much information was found concerning military cleanup activities. As a result, in-depth personal interviewing was used to measure pollution prevention awareness in Aeronautical Systems Center program offices. Interviews, analysis, and comparisons were made between three groups …

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Repair Process Improvement At The Ogden Air Logistics Center, Landing Gear Division: A Case Study In The Application Of The Theory Of Constraints, David A. Maddox, Susan L. Martz Sep 1993

Repair Process Improvement At The Ogden Air Logistics Center, Landing Gear Division: A Case Study In The Application Of The Theory Of Constraints, David A. Maddox, Susan L. Martz

Theses and Dissertations

This study explored the nature and extent of success that resulted from the implementation of the Theory of Constraints (TOC) in a depot repair environment. The actions taken to implement TOC were determined. Performance measures which defined success were identified and data were collected and summarized to demonstrate performance before and after implementation of TOC concepts. Improvements in flowdays and work-in-process (WIP) were determined to be attributable to the TOC effort. In addition, the unique characteristics of probabalistic repair and supply system variability were noted as those characteristics that posed the greatest challenges to implementing TOC in a remanufacturing environment. …

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Scheduling A Medium-Sized Manufacturing Shop: A Simulation Study, Daniel J. Mcfeely Sep 1993

Scheduling A Medium-Sized Manufacturing Shop: A Simulation Study, Daniel J. Mcfeely

Theses and Dissertations

This study examined the application of simple-to-use, low cost scheduling methods to the operating environment of a medium-sized manufacturing shop. Computer simulation was used to evaluate eighteen different scheduling algorithms, each the result of the combination of a loading and a sequencing rule; due date setting was not considered since due dates are exogenously set. The loading rules investigated were Minimum Machine Required, Lowest Average WIP, and Lowest Average Aggregate Priority Level. The sequencing rules investigated were Priority, EDD, FIS, SPT, Slack, and Slack Ratio. The scheduling algorithms were evaluated against performance measures of mean tardiness, mean flowtime, mean percentage …

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A Comparison Of The Disaster™ Scheduling Software With A Simultaneous Scheduling Algorithm For Minimizing Maximum Tardiness In Job Shops, Barak J. Carlson, Christopher A. Lettiere Sep 1993

A Comparison Of The Disaster™ Scheduling Software With A Simultaneous Scheduling Algorithm For Minimizing Maximum Tardiness In Job Shops, Barak J. Carlson, Christopher A. Lettiere

Theses and Dissertations

The Theory of Constraints (TOC) is the foundation for a computerized scheduling system called DISASTER. Although this system has proven successful in many manufacturing settings, it has potential limitations due to the sequential heuristic process by which it schedules constraints. The objective of this thesis was to determine the extent to which these limitations impact the due date performance of schedules created by DISASTER. This objective was addressed by developing an algorithm to simultaneously schedule multiple constraints in a job shop environment and provide the optimal schedule for minimized maximum tardiness. This algorithm was used to obtain solutions for a …

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