Papers by Guilherme Vieira
MPS, 2003
This work presents current results from a research about developing a new method for optimization... more This work presents current results from a research about developing a new method for optimization of production planning problems using genetic algorithms. In this study, fitness is measured in terms of inventory levels, requirements not met, capacity ...
Resumo: Este artigo faz uma abordagem, provavelmente pioneira, de uma análise quantitativa do uso... more Resumo: Este artigo faz uma abordagem, provavelmente pioneira, de uma análise quantitativa do uso do planejamento, previsão e reposição colaborativo (CPFR) em cadeias de suprimento através de simulação computacional. Três indicadores de desempenho de cadeias são utilizados neste estudo: Tempo de ciclo de pedido; variação dos níveis de produção no último estágio da cadeia (fornecedor); e a variação do estoque médio total na cadeia. Quatro estratégias baseadas em colaboração são aplicadas a uma cadeia de suprimentos tradicional e os resultados são comparados com o desempenho obtido com a abordagem atual, isto é, sem colaboração entre os estágios da cadeia. As análises através de experimentos de simulação revelam o que já se descobriu através de casos de cadeias que implementaram o CPFR: Verificou-se que a colaboração realmente traz benefícios significativos à gestão da cadeia de suprimentos.
Revista Gestão Industrial, 2007
Revista de Saúde Pública, 2012
OBJETIVO: Analisar a qualidade dos serviços oferecidos por empresas operadoras de planos de saúde... more OBJETIVO: Analisar a qualidade dos serviços oferecidos por empresas operadoras de planos de saúde, segundo a percepção de usuários. MÉTODOS: Estudo transversal com 360 usuários de sete operadoras de planos de saúde da cidade de Curitiba, PR, e região metropolitana em 2008. Foi aplicado questionário sobre as preferências dos usuários em relação a seis atributos (localização dos pontos de atendimento; efetividade da ação dos médicos, clínicas e hospitais; rapidez e amabilidade no atendimento; facilidade na liberação de guias; preço; abrangência da rede credenciada) de cada uma das empresas operadoras. Para a análise das respostas foi utilizado o método Analytic Hierarchy Process (AHP, ou Processo Analítico de Hierarquia), ferramenta de análise de decisão e planejamento de múltiplos critérios. RESULTADOS: O atributo mais valorizado pelos usuários foi "preço". As empresas foram agrupadas em dois conjuntos de preferências em relação aos atributos: dos sete planos de saúde, dois...
Produção, 2014
One of the most important features to be considered by health service providers when developing a... more One of the most important features to be considered by health service providers when developing and promoting their products (or services) is the consumers' perception of their products' (services') attributes. The purpose of this study is to define the hierarchy for the attributes of services developed by major health plan operators in the city of Curitiba (PR) as perceived their consumers. The classical analytical hierarchy process (AHP) technique, a multicriteria tool for decision analysis and planning, was used to analyze seven companies and six attributes of each of them. The results show that the most meaningful attribute for health service consumers is the "price" and that companies can be separated into the following groups: HP1 and HP2 (Health Plans 1 and 2, with approximately 23% and 19% of consumers preferring each one) and HP3, HP4, HP5, HP6 and HP7 (with approximately 10% of consumers preferring each). Based on the results for each attribute analyzed, the conditions exist for the companies to redefine their structures, processes, prices, and service providers to reach their target customers.
Revista Produção Online, 2012
Revista Produção Online, 2009
as principais tendências de pesquisa nessa área, tanto a nível mundial quanto nacional. Como resu... more as principais tendências de pesquisa nessa área, tanto a nível mundial quanto nacional. Como resultados deste estudo, pode-se vislumbrar a hibridização entre ACO e outros algoritmos de otimização e o tratamento de cenários de JSS cada vez mais complexos como as tendências mais relevantes dos trabalhos envolvendo ACO e problemas de programação de job-shops. Palavras-chave: Otimização combinatória. Job shop scheduling. Otimização por colônia de formigas. Tendências de pesquisa.
IFAC-PapersOnLine, Jul 1, 2017
Complex stochastic job-shop scheduling problems can be handled by simulation-based optimization (... more Complex stochastic job-shop scheduling problems can be handled by simulation-based optimization (SBO), combining the optimization capabilities of meta-heuristics with the system representativeness of simulation models. In order to explore the potential of coupling optimization and simulation techniques in different job shop scheduling scenarios, this paper presents some of the ideas on an ongoing research project developing an SBO strategy coupling genetic algorithm and discrete-event simulation. Furthermore, this paper describes an approach to aid in the analysis of computed schedule feasibility subject to stochastic behavior, which is the case for most of the real world industries. One of the research goals is to provide an efficient and effective way to evaluate schedule robustness and to find robust schedules. The research may significantly contribute to businesses where scheduling changes are expensive, like in airline and train companies and automakers industries and suppliers.
Tactic planning or master production scheduling focuses on time and spatial decomposition of the ... more Tactic planning or master production scheduling focuses on time and spatial decomposition of the aggregate planning targets and forecasts, as well as, forecast and provision of needed resources. This process becomes extremely hard and time consuming with the increase of number of products, resources and periods considered. In face of such obstacles, this work shows a study of an Artificial Intelligence technique called Simulated Annealing applied to the optimization of production planning problem, more specifically, Master Production Scheduling. This work reviews some of the fundamental theory of simulated annealing, the methodology for master production scheduling calculation, the applicability of simulating annealing to planning problems, most important results and suggestions for further studies.
All kind of decision is based on data. Manufacturing enterprises uses integrated systems for day ... more All kind of decision is based on data. Manufacturing enterprises uses integrated systems for day to day transactions and data storage. The way this data is stored do not favor an integrated enterprise analyses. This work goal is to present a Data Warehouse environment reference to integrate data from different modules used in manufacturing enterprises supported by integrated manufacturing systems (called ERP – Enterprise Resources Planning). This environment aggregates some Data Marts that focus in specific subjects. It will be presented some Data Mart proposals for subjects like sales, production and quality; and its utilization in related decision.
Revista Gepros, May 13, 2014
A manufatura enxuta e baseada na filosofia de reduzir o desperdicio, isto e, produzir o modelo co... more A manufatura enxuta e baseada na filosofia de reduzir o desperdicio, isto e, produzir o modelo correto, no momento, quantidade e qualidade corretos. A manufatura classica explora ao maximo a utilizacao das maquinas e postos de trabalho. Os resultados sao maiores quantidades de pecas em processo para justificar o tempo de preparacao da maquina ou posto gargalos. Planejar requer maior entendimento sobre o impacto de cada atividade nos resultados. O metodo CPM possibilita explorar as relacoes das atividades com o lead-time – L.T. Este artigo apresenta a manufatura enxuta com o uso do metodo CPM (Critical Path Method) para obter melhor lead-time. A principal contribuicao deste trabalho foi reduzir 50% do inventario em processo e aumentar em 155% a producao de pecas. A pesquisa objetivou estudar a producao de produtos com demanda variavel a fim de aumentar a capacidade utilizando a tecnica do caminho critico para explorar as relacoes do processo com os recursos humanos e o metodo de trabalho com diferentes tamanhos de lote. Foram analisadas diferentes quantidades de lote e traba-lhador para atender a demanda atual e futura. A proposta de utilizacao do metodo CPM foi avaliada atraves de simulacoes computacionais com dados reais de montagem de bombas de alta pressao. Palavras-chave: Balanceamento. Producao Enxuta. Metodo CPM. Simulacao.
Production, 2015
This article presents an in-depth bibliographic study about the creation, principles, evolution, ... more This article presents an in-depth bibliographic study about the creation, principles, evolution, and practices of the lean philosophy oriented to the services sector. More than 70 papers about "lean thinking"-specially with focus on services-have been carefully reviewed. It presents the principles of lean service in an organized way, companies applying lean service, and best practices and tools in the implementation of lean service. It shows that lean service does not have a single or specific model of tools, practices or standards. In fact, it is a mix of tools and practices that must be applied according the situation found to be improved. Despite the lack of a standards and methodology for use in services, its best practices, inherited from manufacturing, when applied to services can generate large economic and financial results, as well as improvement of workers' behavior. But, like any change process, this study shows that the application of lean in services also suffers resistance. There might be limitations when evaluating lean practices and principles to services, specially those that have not yet been well defined and reported. Other limitations are due to the scarce articles in the literature. However, this research showed that the use of the lean philosophy in services proved to be effective and quite worthwhile. Several cases analyzed presented significant gains and confirmed an increasing and promising future for service companies "thinking lean".
Resumo: Este artigo faz uma abordagem, provavelmente pioneira, de uma análise quantitativa do uso... more Resumo: Este artigo faz uma abordagem, provavelmente pioneira, de uma análise quantitativa do uso do planejamento, previsão e reposição colaborativo (CPFR) em cadeias de suprimento através de simulação computacional. Três indicadores de desempenho de cadeias são utilizados neste estudo: Tempo de ciclo de pedido; variação dos níveis de produção no último estágio da cadeia (fornecedor); e a variação do estoque médio total na cadeia. Quatro estratégias baseadas em colaboração são aplicadas a uma cadeia de suprimentos tradicional e os resultados são comparados com o desempenho obtido com a abordagem atual, isto é, sem colaboração entre os estágios da cadeia. As análises através de experimentos de simulação revelam o que já se descobriu através de casos de cadeias que implementaram o CPFR: Verificou-se que a colaboração realmente traz benefícios significativos à gestão da cadeia de suprimentos.
2009 IEEE/INFORMS International Conference on Service Operations, Logistics and Informatics, 2009
Page 1. Computer simulation in a large mailing company: In search for a robust configuration Guil... more Page 1. Computer simulation in a large mailing company: In search for a robust configuration Guilherme E. Vieira and Reynaldo Lemos Abstract-The paper shows how to use computer simulation to find out the most robust configuration ...
Produção, 2009
which main objective is to evaluate changes to the Surgical Center aiming at being better prepare... more which main objective is to evaluate changes to the Surgical Center aiming at being better prepared for the demand increase expected for the coming years. Four new scenarios were simulated and analyzed, which included restructuring of internal activities and the increase on the number of surgical rooms. The simulation models showed that the suggested changes will benefit the center and that the best scenario should have two new surgical rooms along with the restructuring of the internal activities flow. This will reduce the patient waiting time for surgical room and the rooms' utilization, besides providing a good service to the community until 2010/2011.
2009 IEEE/INFORMS International Conference on Service Operations, Logistics and Informatics, 2009
Page 1. Understanding supply chain robustness Guilherme E. Vieira) and Reynaldo Lemos Abstract-Th... more Page 1. Understanding supply chain robustness Guilherme E. Vieira) and Reynaldo Lemos Abstract-This paper reviews important concepts behind supply chain (SC) problems and instability, which lead to the need to design and operate more robust supply chains. ...
Proceedings of the 2004 Winter Simulation Conference, 2004., 2004
This paper presents a research project being developed at the Industrial and Systems Engineering ... more This paper presents a research project being developed at the Industrial and Systems Engineering Graduate Program at the Catholic University of Paraná (Brazil). The objective is to develop a system to aid professionals from management and logistics areas to evaluate the performance of supply chains through computer simulation. Among the several possibilities for analysis, simulation can allow one to perform detailed studies on the bullwhip effect in supply chains, caused by the demand variation from the point-ofsale to the suppliers. Two performance measures are of particular interest: average inventory level and service level, both for each stage at and for the whole supply chain. The structure considered in this project is the traditional supply chain composed by suppliers, manufactures, distributors (or wholesalers), retailers and customers. A first version of the proposed Arena simulation models is under development and is presented in this paper.
Proceedings of the Winter Simulation Conference, 2005., 2005
This paper presents the development of conceptual models that can be used in the creation of cert... more This paper presents the development of conceptual models that can be used in the creation of certain types of supply chain simulation projects. The supply chain considered is composed of four elements: suppliers, manufacturer, retailers, and the consumer market. The presented ideas can be used in supply chain simulation projects, which objective can be, for instance, to study the bullwhip effect or new collaboration practices. ARENA simulation models using the conceptual models presented are currently under development.
2009 IEEE/INFORMS International Conference on Service Operations, Logistics and Informatics, 2009
There has been an increasing interest in third-party logistic (3PL) evaluation and selection meth... more There has been an increasing interest in third-party logistic (3PL) evaluation and selection methods lately. Proposed methods in academic literature have significant differences, approaches and conditions to be used, yet comprehensive reference of such methods was not found. This problem is considered in this article, which main goal is to make a descriptive analysis of existing methods for evaluation and
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Papers by Guilherme Vieira