Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 152-170). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 152-170). Also available on the Internet.

Manufacturing organizations are facing fragmented markets and increased demand of variety from consumers. As a result, many of these firms have adopted mass customization manufacturing strategies in an effort to offer their customers the freedom of choice while maintaining operational efficiency. Lean manufacturing strategies have also seen heavy use in manufacturing environments. This study investigates the possibilities of integrating lean manufacturing principles and practices into mass customization environments in order to improve system performance. The feasibility of other manufacturing strategies such as agility, Quick Response Manufacturing and the Theory of Constraints assisting in the application of lean manufacturing for mass customization is also explored with the goal of developing a theoretical framework for the application of these manufacturing systems in different types of mass customization environments. The result of these investigations is tested and verified using a real world case study.

Emergency department (ED) acts as a feeder to many hospitals as it determines a large proportion of admissions. ED also acts as a buffer zone for many patients who cannot get care in other institutions due to insurance issues. Most hospitals are trying to invest heavily on their EDs, but cannot meet patients’ satisfaction in terms of cost and quality of care. There is great need for EDs to understand customers’ expectation given the rising cost of healthcare. The focus of this study is at an ED center in Bowling Green Kentucky, using theory of constraints (TOC) thinking process application tools to capture in detail the core and apply TOC to resolve the problems identified. The research was able to identify the core problems as: Backlog of patients in ED, delay in making dispositions, and patients waits on ED to transfer to another facility. The research was able to address the core issues by answering three questions: What to change? This was answered by the CRT “ED unable to meet patients’ expectation.” What to change to? This was answered by the EC “Positive patient outcomes”. How to change? This was answered by the FRT by using injections that resulted to “ED is able to meet patients’ expectations most of the time."

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2006. / The Theory of Constraints is a management philosophy based on the underlying assumption that only a few constraining factors limit the throughput of the entire system. Drum-Buffer-Rope is the production logistical solution of the Theory of Constraints. It is the implementation of Constraints Management on the manufacturing shop floor, to manage physical resource constraints. Drum-Buffer-Rope was designed with the purpose of increasing Throughput, while simultaneously decreasing Inventory, and minimising Operating Expense. It aims to accomplish these goals by focusing on simplifying and therefore reducing variability in the production process, and ultimately protecting order due dates against disruptions. The dynamic conditions under which typical job shops operate can make Constraints Management of the resource constraints a cumbersome task. By following a “What If” approach to the scheduling process, the scheduler can play an interactive role in developing practical shop floor schedules. In this way the scheduler can see the results of his/her ideas on the shop floor situation quickly as immediate feedback is provided. The Drum-Buffer-Rope methodology only finite schedules certain points in the manufacturing process therefore scheduling calculations can be performed quickly if done in software. This makes it possible for the scheduler to analyse various scenarios in a short period of time and allowing the development of near optimal shop floor schedules by following a “What If” approach to scheduling. In this project, new developments in the field of Drum-Buffer-Rope were investigated, and the newly developed Simplified Drum-Buffer-Rope methodology was researched. The methodologies were incorporated in a fully developed software package that uses Drum-Buffer- Rope or Simplified Drum-Buffer-Rope to marry the intrinsic knowledge of the shop-floor worker with modern day computer technology to create production schedules that can be released to the shop floor. Schedules are created rapidly enough by the software to enable the scheduler to follow a “What If” approach to create near optimal shop floor schedules. The developed software was used with live data from a South African job shop to illustrate the “What If” approach to Simplified Drum-Buffer-Rope scheduling. The results show that throughput can be increased and operating expense decreased, therefore increasing bottom line results, by analysing various scenarios.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2007. / This project was initiated to develop a new and novel approach to address complex sequencing problems, in particular, an alternative method was developed to find solutions to the sequential ordering problem. The sequential ordering problem is concerned with the arrangement of a number of elements in a sequence that respects a number of precedence constraints and results in the lowest overall cost. A precedence constraint requires that some element will occur before another in the solution sequence, and the cost of a solution is determined by summing the independent individual costs that are incurred when progressing from one specific element in the solution sequence to another. Instances of this problem are regularly found in the practice of industrial engineering in problems such as the routing of a delivery vehicle, the scheduling of jobs on a machine and the preparation of project plans with limited resources. The sequential ordering problem is known to be complex in the sense that as the size of problem instances increases, the best-known time required to find a guaranteed optimal solution increases exponentially.

Orientador: Fernando Bernardi de Souza / Banca: Roberto Fernandes Tavares Neto / Banca: Andreia da Silva Meyer / Resumo: O presente trabalho tem como objetivo avaliar, por meio de simulação computacional, a regra de sequenciamento de ordens de produção recomendada pelo método Tambor-Pulmão-Corda Simplificado/Gerenciamento do Pulmão (Simplified Drum-Buffer-Rope / Buffer Management - S-DBR/BM) aplicado em ambientes de produção para estoque. Esta aplicação recebe o nome de Make to Availability (MTA), pois visa a um compromisso de atendimento da demanda baseado na pronta-entrega de produtos acabados. Para tanto, tal regra será comparada com as regras de sequenciamento da produção SPT (Shortest Processing Time), FIFO (First in First Out) e random. Para cumprir tal objetivo, será simulada uma fábrica real de manufatura contendo diferentes níveis de demanda e diferentes níveis de coeficiente de variação (CV) da demanda. A variável dependente utilizada para comparação dos desempenhos é o fill rate, que mensura o atendimento da demanda a partir do estoque de produtos acabados. Os resultados indicam que a regra S-DBR/MTA supera os demais métodos em todos os cenários simulados e também que cenários com menor CV da demanda apresentaram melhor fill rate médio que aqueles com maior CV. / Abstract: This dissertation evaluated by computer simulation the production order sequencing rule recommended by the Simplified Drum-Buffer-Rope (S-DBR) applied in make-to-stock environments, called Make to Availability (MTA). MTA method aims at a commitment to meet demand based on the finished products prompt delivery. For this purpose, we compared it with SPT (Shortest Processing Time) sequencing heuristic, FIFO (First In First Out) and random sequencing rules, through demand patterns variations of a real factory. Fill rate was the dependent variable used to compare performances, which is the percentage of demand that is fulfilled directly out of the finished product stock. We show that S-DBR / MTA sequencing rule overcame all other sequencing rules and SPT had the worst fill rate. / Mestre

Critical Chain Project Management (CCPM) is a project scheduling technique which has been developed to overcome some of the deficiencies of traditional methods and where, in a single project environment, the critical chain is the longest chain of activities in a project network, taking into account both activity precedence and resource dependencies. In multi-project environments, the constraint is the resource which impedes projects' earlier completion. CCPM relies on buffers to protect the critical chain and monitor/control the project. The literature review conducted by this study reveals that the research on CCPM principles in multi-project environments is still extremely scarce. The review also suggests that outright elimination of multitasking (i.e. switching back and forth among two or more concurrent tasks) by imposing a relay race mentality (i.e. starting a task as soon as it becomes available and finishing it as soon as possible), as one of the main features of CCPM, might worsen the resource constraints of CCPM portfolios and cause creation of over-protective buffers. It further implies that there is also a good level of multitasking that can benefit such environments by improving resource availability and requiring shorter protective buffers. This research aims to bridge the gap by investigating the impact of level of multitasking on resource availability issues and project and feeding buffer sizing in CCPM portfolios with different resource capacities. This is pursued through adopting a deductive approach and developing five research hypotheses, considering ten different levels of resource capacity, testing the hypotheses by conducting Monte Carlo simulations of randomly generated project data and comparing the results with deterministic duration values of the same portfolios with 30%, 40% and 50% feeding and project buffer sizes. In total, ten portfolios with similar size, variability and complexity levels, each containing four projects, were simulated. It was concluded that: firstly, some limited levels of multitasking, determined in relation to the level of resource capacity, can be beneficial to time performance of CCPM portfolios; secondly, shorter buffer sizes can be accounted for by abolishing the ban on multitasking while maintaining a lower rate of resource capacity; finally, the element of relay race work ethic that completely bans multitasking should not be implemented as it proved to be counterproductive in terms of resource availability. Seven recommendations and a buffer sizing framework are provided as complementary guidelines to practitioners' own experience, knowledge and judgment, in addition to an explanation of theoretical and practical contributions and suggestions for future research.

p. 1-114 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-03-05T19:09:45Z No. of bitstreams: 1 777.pdf: 892053 bytes, checksum: 438ebe26676d224b865a5cf0b702cd77 (MD5) / Approved for entry into archive by Tatiana Lima(tatianasl@ufba.br) on 2013-03-14T18:29:23Z (GMT) No. of bitstreams: 1 777.pdf: 892053 bytes, checksum: 438ebe26676d224b865a5cf0b702cd77 (MD5) / Made available in DSpace on 2013-03-14T18:29:23Z (GMT). No. of bitstreams: 1 777.pdf: 892053 bytes, checksum: 438ebe26676d224b865a5cf0b702cd77 (MD5) Previous issue date: 2006 / O Gerenciamento das Restrições (GR) parte do pressuposto de que a meta de qualquer empresa é ganhar mais dinheiro no presente, bem como no futuro. A Teoria das Restrições é um conjunto de soluções embasadas na Teoria do Caos, que busca o desempenho global do sistema, pela gestão de seus poucos recursos críticos. Esta teoria é aplicada a qualquer empresa, já que estas, por natureza, têm característica sistêmica. O objetivo deste trabalho é avaliar a implantação da metodologia Tambor-Pulmão-Corda com Supermercado, resultante da Teoria das Restrições, na gestão do planejamento e programação de produção, nas unidades de fabricação de eletrodos de grafite da Graftech International Ltd., situadas em Candeias e Monterrey, no período de 2001 a 2004. Projeto piloto, aplicando esta metodologia, foi desenvolvido por um grupo de técnicos da Empresa e, posteriormente, foi aprovado para ser implantado nas demais unidades do grupo. A estratégia de pesquisa adotada foi o estudo de casos. Como resultados da implantação do modelo TPC com Supermercado, temos uma linguagem uniforme de planejamento e programação de produção entre as unidades estudadas e a Corporação, tendência de redução do nível de inventário e o entendimento comum de como gerir as restrições físicas a partir das cinco etapas da Teoria das Restrições: Identificar, explorar, subordinar, elevar e identificar a nova restrição. Por fim, chegamos à conclusão de que o modelo proposto não pode ser dado como implantado em nenhuma das duas unidades estudadas, e que as maiores dificuldades encontradas estão atreladas às restrições não físicas, principalmente no que se refere às políticas de vendas/marketing, contabilidade de custos e busca dos resultados de curto prazo. / Salvador

p. 1-126 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-03-19T18:59:47Z No. of bitstreams: 1 777777.pdf: 984534 bytes, checksum: 6c6fe1f69d886cfb32c205787ae8c9af (MD5) / Approved for entry into archive by Tatiana Lima(tatianasl@ufba.br) on 2013-04-22T18:11:01Z (GMT) No. of bitstreams: 1 777777.pdf: 984534 bytes, checksum: 6c6fe1f69d886cfb32c205787ae8c9af (MD5) / Made available in DSpace on 2013-04-22T18:11:01Z (GMT). No. of bitstreams: 1 777777.pdf: 984534 bytes, checksum: 6c6fe1f69d886cfb32c205787ae8c9af (MD5) Previous issue date: 2005 / Esta dissertação tem por objetivo analisar a implantação de um modelo de gestão em operações baseado na teoria das restrições na UCAR Produtos de Carbono S/A. Trata-se de um estudo de caso, onde, após uma síntese teórica dos princípios gerais da teoria das restrições, faz-se uma avaliação dos resultados obtidos e das dificuldades encontradas na área de operações. Através de aplicação de questionário e suportado por análises de indicadores obtidos nos quatro anos em que vem sendo implementada, conclui-se que a teoria das restrições facilita a gestão, tendo ajudado à obtenção de resultados crescentes nas operações da UCAR, principalmente nos últimos dois anos da implantação. Sendo um processo ainda em andamento, é visualizado pelos gestores como de grande potencial, capaz de trazer resultados significativos. Apesar desta conclusão positiva, alguns desvios foram detectados. Desta forma, por se tratar de uma dissertação de mestrado profissional, também contribui para apontar deficiências encontradas durante a implementação, direcionando algumas possíveis soluções para as etapas seguintes. / Salvador