Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xi, 181 p. : ill. Includes abstract. Includes bibliographical references (p. 162-167).

This thesis is intended to provide the management of small to medium sized job shop companies with a written plan to implement a formal computerized manufacturing planning and control system. The research stemmed from a case study performed at a typical job shop where growth of production activities was complicating the informal control system being used. A review of the literature and a survey of job shops provided the necessary foundation for this implementation. Research indicated that typical material requirements planning (MRP) systems do not provide the type of shop floor control that most job shops require. This thesis suggests alternatives that not only provide the type of shop floor control required by a typical job shop, but software that can be managed effectively by current employees with minimal changes to the education and training of these employees. The plan contains ten steps that are designed to be used by a job shop wishing to implement a formal computerized control system. A decision making heuristic is used in the first step that provides a method for estimating the benefits that might result from implementation. Sample criteria for evaluating current shop floor control software, development of an implementation timeline, cost considerations, educational requirements for employees, and suggested methods for measuring project performance are also included. Examples of the type of improvement that can be expected for each of the business activities is also discussed. The overall goal is to provide a comprehensive plan that will guide managers through the steps necessary to implement a computerized shop floor control system and to inform managers of the benefits which can accrue from such a system. / Graduation date: 1999

Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Edward L. Mooney. Includes bibliographical references (leaves 70-73).

Thesis (Ph. D.)--Lehigh University, 1997. / Includes vita. Bibliography: leaves 109-114.

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 136 p. : ill. Includes abstract. Includes bibliographical references (p. 96-106).

A local utility company processes a variety of jobs each day including meter reading, service shut-offs, emergency response, and customer service work. For the Company, a specific workflow begins with automated meter-reading (AMR) and ends with collections/service shut-offs (CSOs) for accounts with excessively late payments (AMR-CSO workflow). There are considerable and systemic sources of variability in both the workload and resource demands of the AMR-CSO workflow including order arrival, order release schedules, order batch-sizing and maintenance scheduling. This project draws on theory from the job-shop problem to explore possible means to mitigate this variability. We hypothesized that controlling various forms of input variability would lead to reduced downstream workload variability. Using discrete event simulation we tested a variety of measures to reduce input variability in the workflow. Consistent with other literature we find that various workload control tactics have limited impact on output measures and system performance. However, we found that system is much more sensitive to resource capacity variability. One input control tactic we call Targeted Release allowed us to reduce Company capacity variability which suggested significantly improved outcomes. These initial results are promising for both the Company and for future investigation of tactics to mitigate resource capacity variability.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 119-128). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 119-128). Also available on the Internet.

discrete parts manufacturing industries. We are motivated by the production environment of Roketsan Missiles Industries Incorporation, operating at Turkish defense industry. Our objective is to minimize the total weighted completion times of the jobs in the system. We formulate the problem as a mixed integer linear program and find that our model could find optimal solutions only to small sized problem instances. For medium and large sized problem instances, we develop heuristic algorithms with high quality approximate solutions in reasonable solution time. Our proposed heuristic algorithm has hierarchical approach and benefits from optimization models and priority rules. We improve the heuristic method via best move with non-blocking strategy and design several experiments to test the performances. Our computational results have revealed that proposed heuristic algorithm can find high quality solutions to large sized instances very quickly.

A hierarchical control system is proposed for automated flexible manufacturing cells (FMC) that operate in a job shop flow setting. The control system is made up of a higher level scheduler/reactive scheduler, which optimizes the production flow within the cell, and a lower level supervisor that implements the decisions of the scheduler on the shop floor. Previous studies have regularly considered the production scheduling and the supervisory control as two separate problems. This has led to: i) deadlock-prone optimized schedules that cannot be implemented in an automated setting, ii) deadlock-free optimized schedules that lack the means to be transformed into shop floor supervisors, or iii) supervisors that can safely drive the system with no consideration for production performance. The proposed control system combines mathematical models and an insertion heuristic to solve the deadlock-free scheduling problem in job shops, a deadlock-free reactive scheduling heuristic that can revise the schedules upon the occurrence of a wide variety of disruptions, and a systematic procedure that can transform schedules into readily implementable Petri net (PN) supervisors. The integration of these modules into one control hierarchy guarantees a correct, optimized and agile behavior of the controlled system. The performances of the mathematical models, the scheduling and the reactive scheduling heuristics were evaluated by comparison to performances of previous approaches. Experimental results showed that the proposed modules performed consistently better than the other corresponding approaches. The supervisor realization procedure and the overall control architecture were validated by simulation and implementation in an experimental robotic FMC. The control system developed was capable of driving the experimental cell to satisfactorily complete the processing of different product mixes that featured complex processing routes through the cell.