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You searched for +publisher:"University of Michigan" +contributor:("Hu, S. Jack"). Showing records 1 – 3 of 3 total matches.

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University of Michigan

1. Abad, Andres G. Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems.

Degree: PhD, Industrial & Operations Engineering, 2010, University of Michigan

Increasing global competition demands that the manufacturing industry move from mass production into mass customization production in order to provide more varieties of products and thus satisfy customer demands. It has been shown that the increase of product variety has a negative impact on manufacturing system performance. Therefore, it is essential to understand how product variety complicates an assembly system, affecting its operation performance. Such knowledge, once validated, can be further used to improve manufacturing system design and operation. The objective of this dissertation is to develop an enhanced general methodology for modeling and analyzing process complexity for mixed model assembly systems. The following fundamental research has been conducted: A set of complexity metrics are proposed for measuring the complexity of various elements in a manufacturing system. These metrics are proposed by constructing a linkage with the communication system framework. Unlike the existing complexity measures defined in the literature, this research is the first effort to include production quality into the measurement of how well a manufacturing system can handle the process complexity induced by the input demand variety. A systematic method is developed for efficiently and explicitly representing complex hybrid assembly system configurations by the use of algebraic expressions, which can overcome drawbacks of two widely used representation methods: block diagrams and adjacency matrices. By further extending the algebraic configuration operators, the algebraic performance operators are defined for the first time for the systematic evaluation of system performance metrics; these metrics include quality conforming rates for individual product types at each station, process capability for handling complexity, and production cycle time for various product types. Therefore, when compared to other methods, the proposed algebraic expression modeling method also has a unique merit in providing computational capability for automatically evaluating various system performance metrics. An integrated model is introduced for the first time to describe the effect of operator’s factors on the process operation performance. The model includes intrinsic factors such as the operator’s thinking time and experience; and extrinsic factors such as the choice task complexity induced by the product variety in mixed model assembly systems. Advisors/Committee Members: Jin, Jionghua (committee member), Herrin, Gary D. (committee member), Hu, S. Jack (committee member), Zhu, Ji (committee member).

Subjects/Keywords: Complexity; Assembly; System; Variety; Configuration; Mixed Model; Industrial and Operations Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Abad, A. G. (2010). Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/77812

Chicago Manual of Style (16th Edition):

Abad, Andres G. “Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems.” 2010. Doctoral Dissertation, University of Michigan. Accessed November 19, 2019. http://hdl.handle.net/2027.42/77812.

MLA Handbook (7th Edition):

Abad, Andres G. “Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems.” 2010. Web. 19 Nov 2019.

Vancouver:

Abad AG. Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems. [Internet] [Doctoral dissertation]. University of Michigan; 2010. [cited 2019 Nov 19]. Available from: http://hdl.handle.net/2027.42/77812.

Council of Science Editors:

Abad AG. Modeling and Analysis of Process Complexity and Performance in Mixed Model Assembly Systems. [Doctoral Dissertation]. University of Michigan; 2010. Available from: http://hdl.handle.net/2027.42/77812

2. Riggs, Robert J. Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States.

Degree: PhD, Industrial and Operations Engineering, 2015, University of Michigan

Remanufacturing is a promising product recovery method that brings new life to cores that otherwise would be discarded thus losing all value. Disassembly is a sub-process of remanufacturing where components and modules are removed from the core, sorted and graded, and directly reused, refurbished, recycled, or disposed of. Disassembly is the backbone of the remanufacturing process because this is where the reuse value of components and modules is realized. Disassembly is a process that is also very difficult in most instances because it is a mostly manual process creating stochastic removal times of components. There is a high variety of EOL states a core can be in when disassembled and an economic downside due to not all components having reuse potential. This thesis focuses on addressing these difficulties of disassembly in the areas of sequence generation, line balancing, and throughput modeling. In Chapter 2, we develop a series of sequence generation models that considers the material properties, partial disassembly, and sequence dependent task times to determine the optimal order of disassembly in the presence of a high variety of EOL states. In Chapter 3, we develop a joint precedence graph method for disassembly that models all possible EOL states a core can be in that can be used with a wide variety of line balancing algorithms. We also develop a stochastic joint precedence graph method in the situation where some removal times of components are normal random variables. In Chapter 4, we further advance the analytical modeling framework to analyze transfer lines that perform routing logics that result from a high variety of EOL states, such as a restrictive split routing logic and the possibility that disassembly and split operations can be performed at the same workstation. Advisors/Committee Members: Hu, S. Jack (committee member), Ni, Jun (committee member), Byon, Eunshin (committee member), Van Oyen, Mark Peter (committee member).

Subjects/Keywords: Modeling and optimization of disassembly systems; Industrial and Operations Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Riggs, R. J. (2015). Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/111570

Chicago Manual of Style (16th Edition):

Riggs, Robert J. “Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States.” 2015. Doctoral Dissertation, University of Michigan. Accessed November 19, 2019. http://hdl.handle.net/2027.42/111570.

MLA Handbook (7th Edition):

Riggs, Robert J. “Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States.” 2015. Web. 19 Nov 2019.

Vancouver:

Riggs RJ. Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States. [Internet] [Doctoral dissertation]. University of Michigan; 2015. [cited 2019 Nov 19]. Available from: http://hdl.handle.net/2027.42/111570.

Council of Science Editors:

Riggs RJ. Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States. [Doctoral Dissertation]. University of Michigan; 2015. Available from: http://hdl.handle.net/2027.42/111570

3. Dong, Fang. Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding.

Degree: PhD, Industrial & Operations Engineering, 2013, University of Michigan

Shipbuilding is a unique industry that uses a wide variety of manufactured components and requires a large number of workers possessing various skills as well as specialized facilities. In recent decades, the U.S. Naval shipbuilding industry has faced challenges of building ships on-time and within budgeted cost. The main problems in Naval ship production are high variability in production workload, ineffective production control, and low facility utilization. Our research emphasizes an innovative production system design and control to improve the shipbuilding production performance. We introduce (1) operational flexibility at the execution level and (2) the release policy Constant Work in Process (CONWIP) concepts at strategic level to shipbuilding. The systems are formulated as flexible queueing networks, and Markov Decision Process (MDP) approach is applied to gain structural insights into the optimal control policy and to optimize the key performance measures such as cost, throughput, and cycle time. Results show that the flexibility bring the robustness to the system which mitigates the variability of the block processing time and also achieve a quicker response to the workload change. We also develop efficient control policies to control the flexible resource which minimize the average holding cost of ship blocks and also improve the system throughput. Another research area we investigate is the outfitting process in shipbuilding. The outfitting refers to the process of fabrication and installation of non-structural components, and represents as much as 50% of the cost of the ship, and up to 50% of ship construction time in many instances. However, due to disturbances from unexpected delays, system variations, capacity limitations, and technological constraints, scheduling of outfitting processes is very complex and can delay the entire ship production system. Therefore, a strategic level planning model and a dynamic control model are developed to provide analytical information which improves the planning and controlling of the outfitting process. Advisors/Committee Members: Singer, David Jacob (committee member), Van Oyen, Mark Peter (committee member), Collette, Matthew David (committee member), Hu, S. Jack (committee member), Seiford, Lawrence M. (committee member).

Subjects/Keywords: Shipbuilding, Operational Flexibility, CONWIP Policy, Queueing Networks, Markov Decision Processes, Closed Queueing Networks, Dynamic Control; Industrial and Operations Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Dong, F. (2013). Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/99814

Chicago Manual of Style (16th Edition):

Dong, Fang. “Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding.” 2013. Doctoral Dissertation, University of Michigan. Accessed November 19, 2019. http://hdl.handle.net/2027.42/99814.

MLA Handbook (7th Edition):

Dong, Fang. “Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding.” 2013. Web. 19 Nov 2019.

Vancouver:

Dong F. Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2019 Nov 19]. Available from: http://hdl.handle.net/2027.42/99814.

Council of Science Editors:

Dong F. Dynamic Control of Flexible Queueing Networks with Application to Shipbuilding. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/99814

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