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In this thesis, we consider determining the economic lot sizes for a finite production rate assembly system with n facilities. Costs at each facility consist of a stationary positive echelon holding cost, and a fixed set up cost. The goal is to determine the production lot size at each facility in order to minimize the long-run total average cost of the system. Power-of-two policies, in which the lot size at each facility is a power of two times some base lot size, are considered. A 94%-effective power-of-two policy is determined from the optimal solution to a continuous relaxation problem by an O(n) algorithm, while a 98%-effective power-of-two policy is found using an O(n log n) algorithm. Near optimal solutions to the continuous relaxation problem are found by a subgradient optimization procedure and a cyclic coordinate descent method. Computational results suggest both methods are efficient for very large systems.

This thesis compares three approaches for assigning workers and scheduling the flow of jobs in a Group Technology (GT) cell. The performance measure considered is the throughput time of jobs. The performance of the three strategies is analyzed by varying the following factors: (1) The ratio of Batch processing time to setup time. (2) Utilization. (3) The number of operators assigned to the cell. The scheduling strategies considered are Individual Machine Loading, Cell Dedication and Worker Batch Assignment. Analytical queueing models as well as computer simulations are used to compare the performance of the scheduling strategies. The dedicated cells perform best with large batch sizes and moderate workloads. The Worker Batch Assignment strategy does as well as traditional batch handling techniques with respect to the throughput time measure. This may be important since this kind of job assignment strategy has the advantage of augmenting quality (due to direct accountability) and enhancing morale without adversely impacting throughput times.

Mechanical tolerancing is a critical phase of product and manufacturing process design. Tolerance, the permissible variation of a dimension, is integral to the product design, manufacturing process and customer satisfaction. / In practice, the tolerance specification task is traditionally performed sequentially, starting with the product design and followed with manufacturing process. A lack of communication between engineering designers and process engineers creates a design that is frequently changed, resulting in longer product lead time. This separate activity leads to product designs which may not be amenable to optimal manufacturing methods. To enhance product manufacturability, quality and design robustness, the design and manufacturing tolerances should be optimized concurrently. The integration of the tolerances ensures that optimality is achieved, which significantly improves the manufacturability, assemblability and robustness of the product. The research presented in this dissertation has dual central objectives: the formulation of an analytical model for integrated design and manufacturing tolerancing and the development of an algorithm for the optimization problem. / A beta distribution approximation method is developed, formulated and validated for both tolerance analysis and synthesis. Genetic algorithms are modified and enhanced to carry out the optimization procedure. Tolerances are determined by considering functional design requirements, assembly stack-up conditions, and machining stock removals based on design robustness maximization. An application of tolerance analysis and synthesis based on the beta distribution approximation method is developed. It provides a reliable method to concurrently optimize design and manufacturing tolerances. / The probabilistic technique developed for the robust tolerancing problems is compared with the traditionally used root sum squares calculation. The results show that the formulation of the beta distribution approximation method not only simulates normal distributions, but also models various practical manufacturing processes beyond the capability of normal distributions. / This research has presented a systematic approach to analyzing and synthesizing design and manufacturing tolerances. By implementing the methodology presented in this research, the designer is able to assign the optimal design tolerances on component dimensions based on assembly requirements, to select the best manufacturing process and to obtain the optimal manufacturing tolerances for component fabrication. / Source: Dissertation Abstracts International, Volume: 55-09, Section: B, page: 4076. / Major Professor: H.-P. Ben Wang. / Thesis (Ph.D.)--The Florida State University, 1994.

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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3718. Adviser: Srinivasa M. Salapaka. Includes bibliographical references (leaves 144-148) Available on microfilm from Pro Quest Information and Learning.

Thesis (M. Phil.)--University of Hong Kong, 1980.