Guilherme Ernani Vieira

A new multi-objective optimization method for master production scheduling problems using simulated annealing

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.

A conceptual model for the creation of supply chain simulation models

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

A new and practical heuristic for Master Production Scheduling creation

This paper describes the most common aspects, parameters, and objectives involved in the Master Production Scheduling (MPS) creation process. It also proposes a practical heuristic for the MPS creation and gives an illustrative example of how to use the proposed method. Although MPS has been widely used and studied, its complexity, mainly due to limited production capacity, flexible fabrication routings, and tight and conflicting performance objectives, has yet to be fully described in the literature. This is also one of the objectives of the presented study. The paper shows some of the decisions involved in creating an MPS, such as balancing conflicting objectives, like maximizing service and minimizing inventory levels, defining backlogging, product types and quantities, resource utilization, and optimal inventory levels. The heuristic proposed considers the most common parameters and decision variables included in an MPS process, and the example further illustrates the complex task of MPS creation.

Lean philosophy and its applications in the service industry: a review of the current knowledge

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”.

Hierarchical and centralized architectures for distributed production planning, scheduling and control activities

This work reviews some of the basic ideas behind centralized and hierarchical architecture, especially focusing on internal logistics activities. It also bring initial thoughts for a methodology to help select (or design) control architecture for distributed production planning, scheduling and control. This methodology would focus on two main aspects: (1) a response-time based approach to be used as the input to measure the effect of different CAs in the system performance, and (2) an activity-based approach for the creation of simulation and control models.

Modelagem e análise de um novo centro cirúrgico para um hospital em crescimento: uma abordagem baseada em simulação

Uma instituicao hospitalar precisa de constante aperfeicoamento para ser eficiente no seu principal negocio: o bem-estar do ser humano. Este artigo descreve um projeto realizado no Hospital Universitario da PUCPR, cujo principal objetivo e avaliar alteracoes no Centro Cirurgico com o intuito de se preparar melhor para o aumento de demanda esperado para os proximos anos. Foram simulados e analisados quatro novos cenarios, os quais incluiram restruturacao de atividades de atendimento e ampliacao do numero de salas cirurgicas. Os modelos de simulacao mostraram que em geral as alteracoes sugeridas trarao beneficios ao centro e que o melhor cenario devera ter duas novas salas de cirurgia e uma restruturacao das atividades internas do centro. Isto reduzira o tempo de espera do paciente por sala cirurgica e tambem a propria taxa de ocupacao das salas, alem de atender bem a comunidade ate 2010/2011.A hospital institution needs frequent improvement to be efficient at its core business: the care of the human being. This paper describes a project conducted at PUCPR’s University Hospital, 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.

Understanding supply chain robustness

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. Based on several works reviewed, a supply chain is considered robust when it is insensitive to variations or noises in not so regular operating conditions. Those adopting robust-oriented approaches (techniques) will have more chance to stay successful in the market.

Fractional factorial analysis to the configuration of simulated annealing applied to the multi-objective optimization of master production scheduling problems

Searching for the global optimal solution in a Master Production Scheduling problem usually demands an effort most industries are not willing to pay. Therefore, the use of meta-heuristics that generates good solutions in reasonable computer time becomes an attractive alternative. However, such strategies are usually complex to implement and configuring their parameters is not a trivial task because of the number of usually conflicting objectives involved. The use of statistical methods that facilitate the set-up of the heuristics parameters becomes therefore necessary. Knowing which parameters are more important, that is, the ones that really affect the solution quality, and those that are irrelevant, is very important for chosen technique performance. This work presents how fractional factorial analysis can be applied to the configuration of simulated annealing used for optimization of Master Production Scheduling problems. Two scheduling scenarios illustrate the use of the proposed method.

Details of the analytic hierarchy process technique for the evaluation of health insurance companies

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.

A brief literature review on decision methods analysis for 3PL selection

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 selection of 3PL providers. A classification of methods is made using characteristics commonly highlighted in academic literature. This paper is an exploratory study and main expected result is a reference of current 3PL selection and evaluation researches. Most of the analyzed methods for 3PL selection and evaluation considered a mixed between qualitative and quantitative approaches and are not based in real cases. Descriptions of which method to use in each particular situation was not found.