A metodologia de projeto e avaliação de experimentos aplicada à indústria de processos

Neste trabalho discute-se os fundamentos do Projeto Estatístico de Experimentos e sua utilização no planejamento, execução e análise de experimentos industriais. Este estudo toma como base um caso ocorrido na indústria alimentícia, com inúmeras falhas no planejamento. A avaliação das rodadas do experimento foi feita através da utilização de índices múltiplos de desempenho, derivados da Função de Perda de Taguchi, os quais são discutidos no trabalho. Três técnicas de regressão linear múltipla são abordadas na análise dos dados do experimento: a Regressão Múltipla Convencional, a Regressão Robusta e a Ridge Regression. Sua utilização é detalhada e os resultados obtidos são comparados quanto ao desempenho. Finalmente, conclui-se o trabalho apresentando-se um projeto experimental considerado adequado para o experimento em estudo, o Projeto Composto de Segunda Ordem, desenvolvido por George Box.This thesis deals with the fundamentals of the Statistical Design of Experiments and its application in planning, executing and analysing industrial experiments. A case from the the food industry, with several planning defficiencies, is taken as an example. The analysis of the experimental runs in this case was made through performance indexes for experiments with multiple response variables, derived from Taguchi's Loss Function. These indexes are presented and discussed. Three multiple linear regression techniques are discussed here through their utilization in the analysis of the experimental data: the Least Squares Regression, the Robust Regression and the Ridge Regression. The results obtained from each technique are compared on a performance basis. The thesis is finished with the presentation of an experimental design which was considered "ideal" for the case in study: the Second Order Composite Design, developed by George Box

Estimativa de confiabilidade de sistemas multi-estado k-em-n aplicada a sistemas de informação

Sistemas de informação podem apresentar falhas que representam impactos de diferente severidade para as empresas. Os modelos de análise de confi abilidade usualmente baseiam-se na ocorrência de falhas através da análise de tempos até falha; tais modelos, porém, não contemplam a severidade dos impactos causados pelas falhas. Neste artigo propõese um modelo de análise de confi abilidade de sistemas de informação baseado na análise de confi abilidade de sistemas multi-estados k-em-n. O modelo contempla a severidade dos impactos causados pelas falhas, além prover uma melhor representação da realidade operacional de sistemas de informação. Um estudo de caso ilustra os desenvolvimentos propostos no artigo.Failures representing impacts of different severity may occur in information systems. Reliability analysis models are usually based on the occurrence of failures through the analysis of failure times; such models rarely take into account the severity of failures in the analysis. This paper proposes a model for the reliability analysis of information systems, which are treated as multi-state k-out-of-n systems. The model considers the severity of failures and their impact on reliability fi gures, providing a better representation of information systems in practice. A case example illustrates the developments proposed in the paper

Design macroergonômico : uma proposta metodológica para projeto de produto

Neste trabalho é apresentada a metodologia de Design Macroergonômico, auxiliar no projeto ergonômico de produtos e postos de trabalho. A metodologia baseia-se em preceitos de macroergonomia e faz uso de técnicas estatísticas, bem como de ferramentas de análise de decisão. Sua principal característica é a promoção da participação dos usuários (trabalhadores) no projeto de produtos e postos de trabalho; itens a serem considerados no projeto são essencialmente determinados pelos usuários. A metodologia é implementada através de um procedimento em sete etapas. Um estudo de caso, tendo como objeto o projeto de cabines para cobrança de pedágio, ilustra a aplicação da metodologia.In this paper we propose Macroergonomic Design, a methodology for the products and work stations design using concepts of macroergonomics, along with statistical and decision analysis techniques. The main idea is to favour designs that are essentially user-driven, with key design features selected to best meet users ergonomic requirements. To capture those requirements and translate them into the design appropriatelly, a seven-step procedure is suggested. The methodology is applied in a case stydy from the transportation industry

Approaches to the rationalization of surgical instrument trays: scoping review and research agenda

BACKGROUND: Surgical Tray Rationalization (STR) consists of a systematic reduction in the number of surgical instruments to perform specific procedures without compromising patient safety while reducing losses in the sterilization and assembly of trays. STR is one example of initiatives to improve process performance that have been widely reported in industrial settings but only recently have gained popularity in healthcare organizations. METHODS: We conduct a scoping review of the literature to identify and map available evidence on surgical tray management. Five methodological stages are implemented and reported; they are: identifying research questions, identifying relevant studies, study selection, charting the data, and collating, summarizing and reporting the results. RESULTS: We reviewed forty-eight articles on STR, which were grouped according to their main proposed approaches: expert analysis, lean practices, and mathematical programming. We identify the most frequently used techniques within each approach and point to their potential contributions to operational and economic dimensions of STR. We also consolidate our findings, proposing a roadmap to STR with four generic steps (prepare, rationalize, implement, and consolidate) and recommended associated techniques. CONCLUSIONS: To the best of our knowledge, ours is the first study that reviews and systematizes the existing literature on the subject of STR. Our study closes with the proposition of future research directions, which are presented as nine research questions associated with the four generic steps proposed in the STR roadmap

Surgery scheduling heuristic considering OR downstream and upstream facilities and resources

Background: Surgical theater (ST) operations planning is a key subject in the healthcare management literature, particularly the scheduling of procedures in operating rooms (ORs). The OR scheduling problem is usually approached using mathematical modeling and made available to ST managers through dedicated software. Regardless of the large body of knowledge on the subject, OR scheduling models rarely consider the integration of OR downstream and upstream facilities and resources or validate their propositions in real life, rather using simulated scenarios. We propose a heuristic to sequence surgeries that considers both upstream and downstream resources required to perform them, such as surgical kits, post anesthesia care unit (PACU) beds, and surgical teams (surgeons, nurses and anesthetists). Methods: Using hybrid flow shop (HFS) techniques and the break-in-moment (BIM) concept, the goal is to find a sequence that maximizes the number of procedures assigned to the ORs while minimizing the variance of intervals between surgeries’ completions, smoothing the demand for downstream resources such as PACU beds and OR sanitizing teams. There are five steps to the proposed heuristic: listing of priorities, local scheduling, global scheduling, feasibility check and identification of best scheduling. Results: Our propositions were validated in a high complexity tertiary University hospital in two ways: first, applying the heuristic to historical data from five typical ST days and comparing the performance of our proposed sequences to the ones actually implemented; second, pilot testing the heuristic during ten days in the ORs, allowing a full rotation of surgical specialties. Results displayed an average increase of 37.2% in OR occupancy, allowing an average increase of 4.5 in the number of surgeries performed daily, and reducing the variance of intervals between surgeries’ completions by 55.5%. A more uniform distribution of patients’ arrivals at the PACU was also observed. Conclusions: Our proposed heuristic is particularly useful to plan the operation of STs in which resources are constrained, a situation that is common in hospital from developing countries. Our propositions were validated through a pilot implementation in a large hospital, contributing to the scarce literature on actual OR scheduling implementation

Aplicação de um modelo de riscos concorrentes na análise de confiabilidade de dados de garantia

Em análise de confiabilidade, espera-se que dados de vida de equipamentos sigam uma distribuição de probabilidade conhecida, como, por exemplo, uma distribuição de Weibull ou Lognormal. Entretanto, quando se modelam falhas originadas em campo, essas podem decorrer de causas múltiplas e os tempos-até-falha podem, assim, estar associados a diferentes estágios do ciclo de vida de um produto, não se ajustando a uma distribuição de probabilidade única. Neste artigo, propõe-se a utilização de um modelo misto que possa ser aplicado na análise de dados de vida oriundos de duas fases do ciclo de vida de um produto: a fase de vida operacional e a fase de envelhecimento (desgaste). O modelo proposto combina elementos de uma distribuição exponencial e de uma distribuição de Weibull com dois parâmetros. Equações de confiabilidade e estimadores de máxima verossimilhança são empregados para definir os parâmetros do modelo e para ilustrar os desenvolvimentos propostos. Um teste de ajuste é utilizado para verificar o desempenho do modelo sugerido

Loss and improvement analysys based on lean concepts applied to the wine industry

Nos últimos anos, o setor vinícola nacional vem apresentando diversas transformações em seus processos produtivos. Melhorias focadas na qualidade final do produto, bem como no processo de produção em si, passaram a ser fundamentais à sobrevivência do setor frente ao crescente volume de vinhos importados disponíveis no mercado nacional. De tal forma, perdas no processo produtivo devem ser minimizadas e/ou eliminadas para assegurar a competitividade do segmento nacional. Este artigo apresenta uma aplicação inédita dos conceitos do Sistema Toyota de Produção (STP) na melhoria do processo produtivo em uma empresa vinícola. No estudo de caso que ilustra o artigo, a linha de engarrafamento foi identificada como concentradora das perdas de produção mais pronunciadas, por intermédio de entrevistas e filmagem dos procedimentos envolvidos. Ferramentas oriundas da Engenharia de Produção, como mudança de layout e desenvolvimento de dispositivos anti-falhas, foram implementadas na linha de engarrafamento. As modificações propostas conduziram à redução do transporte de insumos, eliminação de perdas por ruptura de vasilhame e otimização do número de operários no setor

Hospital Investment Decisions in Healthcare 4.0 Technologies: Scoping Review and Framework for Exploring Challenges, Trends, and Research Directions

BACKGROUND: Alternative approaches to analyzing and evaluating health care investments in state-of-the-art technologies are being increasingly discussed in the literature, especially with the advent of Healthcare 4.0 (H4.0) technologies or eHealth. Such investments generally involve computer hardware and software that deal with the storage, retrieval, sharing, and use of health care information, data, and knowledge for communication and decision-making. Besides, the use of these technologies significantly increases when addressed in bundles. However, a structured and holistic approach to analyzing investments in H4.0 technologies is not available in the literature. OBJECTIVE: This study aims to analyze previous research related to the evaluation of H4.0 technologies in hospitals and characterize the most common investment approaches used. We propose a framework that organizes the research associated with hospitals’ H4.0 technology investment decisions and suggest five main research directions on the topic. METHODS: To achieve our goal, we followed the standard procedure for scoping reviews. We performed a search in the Crossref, PubMed, Scopus, and Web of Science databases with the keywords investment, health, industry 4.0, investment, health technology assessment, healthcare 4.0, and smart in the title, abstract, and keywords of research papers. We retrieved 5701 publications from all the databases. After removing papers published before 2011 as well as duplicates and performing further screening, we were left with 244 articles, from which 33 were selected after in-depth analysis to compose the final publication portfolio. RESULTS: Our findings show the multidisciplinary nature of the research related to evaluating hospital investments in H4.0 technologies. We found that the most common investment approaches focused on cost analysis, single technology, and single decision-maker involvement, which dominate bundle analysis, H4.0 technology value considerations, and multiple decision-maker involvement. CONCLUSIONS: Some of our findings were unexpected, given the interrelated nature of H4.0 technologies and their multidimensional impact. Owing to the absence of a more holistic approach to H4.0 technology investment decisions, we identified five promising research directions for the topic: development of economic valuation methodologies tailored for H4.0 technologies; accounting for technology interrelations in the form of bundles; accounting for uncertainties in the process of evaluating such technologies; integration of administrative, medical, and patient perspectives into the evaluation process; and balancing and handling complexity in the decision-making process