Alexandre Ferreira de Pinho

Conceptual modeling in simulation projects by mean adapted idef: an application in a brazilian tech company

Several process modeling techniques have been used in simulation projects. However, most of these techniques provide little specific support to the programming. The main cause of this is the fact that these techniques were not developed with the same logic used in simulation models. From this issue, this paper presents an industrial application of a new conceptual modeling technique, named IDEF-SIM (Integrated Definition Methods - Simulation) currently under development by the authors. This adapted IDEF uses logic elements present in techniques such as IDEF0 and IDEF3, but in a way that is similar to the process interpretation logic usually used in simulation projects. This way, it can be noticed an increase in the conceptual models utility, which might facilitate the simulation model programming, verification and validation and the scenarios creation. Additionally, the paper presents the benefits of using IDEF-SIM to create the conceptual model of a Brazilian tech company manufacturing cell.

Gestão do Conhecimento na análise de falhas: mapeamento de falhas através de sistema de informação

The managerial excellence is based on the company competence to produce, store and disseminate knowledge. Such an importance is even more justified by the use of knowledge to analyze failures in order to avoid undesirable consequences and guarantee the system reliability. In this context, this article presents a Knowledge Management application in an electric energy company. The main aim of this article is to present a method for mapping failures through an information system. This system provides failure trees, which storage photos, procedures, management descriptions of failures and, to avoid relapse, previous ways of solutions. In short, this work provides a practical application of the Knowledge Management approach to the failure analysis subject.

Economic evaluation of the increase in production capacity of a high technology products manufacturing cell using discrete event simulation

This paper presents an application of the modeling and simulation methodology along with the Design of Experiments (DOE) to aid the decision makers to know the economic risk they are taking when there are many scenarios. Firstly, the production process was studied and documented by a SIPOC, an IDEF0 and a Flowchart. These techniques were combined to elaborate the simulation conceptual model. After that, the probability distributions were chosen and fed the computer model, built to emulate the real system. The simulation model was verified and statistically validated. Sixty four possible scenarios were tested, and in this case, the DOE may contribute to select the scenarios which are relevant to the economic analysis. The simulator used was Promodel® which provided the output to fed the cash flow of each scenario. Finally, the Net Present Value (NPV) and the economic risk of each scenario were calculated.

ANÁLISE DE FALHAS ATRAVÉS DA APLICAÇÃO DO FMEA E DA TEORIA GREY

Este artigo tem como objetivo analisar as causas de falhas potenciais atraves da avaliacao do RPN (risk priority number), apresentado na literatura na abordagem do FMEA (Failure Mode and Effect Analysis). O RPN sera determinado atraves da teoria Grey, contribuindo desta maneira para contornar alguns problemas apresentados na literatura a respeito do metodo tradicional de calculo do RPN. O artigo apresentara uma descricao passo a passo desta tecnica, aplicada ao processo de distribuicao de energia eletrica. Para isto, foram analisadas algumas falhas identificadas em uma distribuidora. Por fim, a analise considerou uma ponderacao diferente para os fatores do FMEA, evidenciando as possibilidades de analise desta tecnica.

Analysis of the applicability of the IDEF-SIM modeling technique to the stages of a discrete event simulation project

The IDEF-SIM technique was developed in order to facilitate the translation of conceptual models to computational models. Papers using this technique can be found in the existing literature, however, none present an analysis of how the technique behaves throughout all of the stages of a discrete event simulation project. Therefore, a research-action was developed with the practical objective of constructing a computational model as a help to future decision making. The knowledge objective is to analyze the applicability of this technique in all of the stages of the discrete event simulation project. It was concluded that the IDEF-SIM demonstrates as applicable: during the conception stage in which information of the process was documented in detail; during the implementation stage in which the conceptual model was converted into a computational model; and during the analysis phase, promoting the communication between modulators and managers in the presentation of proposed changes.

Evaluating Energy Sector Investments: Calculating Volatility

A major task in assessing risks of investment projects is defining the approach to calculating the project’s volatility. Looking at assorted estimation techniques, this paper calculates their volatilities. The techniques originate from authors in the area and involve project-specific variables of uncertainty. These techniques are applied to a case of electricity distribution through real options. Results are then compared. The difference between the calculated volatilities was low, leaving, in the case of the project evaluated here, the decision unchanged. The paper’s contribution consists of providing a detailed presentation of calculating volatility by the methods cited and by comparing the results obtained by its application.

Análise de uma unidade de processamento de roupas de um hospital através da simulação a eventos discretos

Com o passar do tempo a simulacao a eventos discretos tem sido utilizada de forma crescente para auxilio a tomada de decisoes. Esta ja e apontada como uma das tecnicas de pesquisa mais utilizadas, devido principalmente a sua versatilidade, flexibilidade e poder de analise. No setor de servicos, embora sua aplicacao ainda nao seja tao difusa quanto nos ambientes de manufatura, isso nao tem sido diferente. Este artigo tem como objetivo desenvolver um projeto de simulacao em uma unidade de processamento de roupas de um hospital do interior de Sao Paulo, como ferramenta de apoio a tomada de decisao gerencial. A simulacao permitiu apresentar a direcao do hospital a capacidade da unidade de processamentos de roupas, bem como apontar pontos criticos e gargalos do processo. Os resultados alcancados contribuiram para identificar oportunidades de melhoria no sistema, bem como contribuir para com a literatura para uma maior discussao sobre o assunto.

AVALIAÇÃO DA OPERAÇÃO DE SETUP EM UMA CÉLULA DE MANUFATURA DE UMA INDÚSTRIA DE AUTOPEÇAS ATRAVÉS DA SIMULAÇÃO A EVENTOS DISCRETOS

Os ambientes de manufatura tem se tornado cada vez mais complexos e consequentemente os processos de tomada de decisao vem adquirindo complexidade na mesma proporcao. Neste contexto a simulacao computacional tem se mostrado uma valiosa ferramenta capaz de ajudar na melhoria de processos e analise de mudancas. Este trabalho buscou por meio de um projeto de simulacao computacional em uma celula de manufatura de uma empresa fornecedora de autopecas, determinar a melhor forma de execucao de setup: dedicado ou em etapas. Concluiu-se que independentemente da forma como o setup era realizado, dedicado ou em etapas, a producao media da celula era estatisticamente igual. Sendo assim, como o setup dedicado era de execucao mais facil, outros tres cenarios foram criados a partir deste visando a otimizacao da operacao de setup e aumento de produtividade da celula. Estes cenarios foram construidos em acordo com os tomadores de decisao da empresa para que assim pudessem escolher o que melhor atendesse as suas necessidades.

Relevant Points for Thermodynamic Diagnosis Application Using the Reconciliation Method

After some hours of operation, every power plant’s equipment begins to show degraded performance. The amount of equipment degradation and the gain that can be achieved in plant heat rate and power generation by the replacement or repairing of each component is important information for proper plant maintenance management. This paper aims to show how diagnosis and prognosis of a power plant can be performed based on thermodynamic data measured by plant instrumentation on site. Some important points such as how to increase the accuracy of the prognostic by developing the complete Taylor series and how it affects the thermodynamic state are also explained. Practical considerations for implementing a thermodynamic diagnosis/prognosis system in a real plant are also discussed. The system receives thermodynamic data from the plant information system (PI) and after a filtering step, the performance factors (PFs) of each component are calculated based on the component’s performance curves. Thus, the current state can be modeled using these PFs. By replacing the calculated performance factors, component by component, with factors that represents no degradation, future cycle performance can be estimated. This work is a partial result of an ongoing research program that implements a thermodynamic diagnosis/prognosis system on a 130 MW combined cycle co-generation power plant.Copyright