Resumo em Inglês:

ABSTRACT This study is devoted to the optimal control of a hybrid manufacturing system with returned products after usage, represented as an infant mortality mode under a periodic review policy. Three hybrid models have been discussed; remanufacturing is continuous along the planning period (without a disposal option), remanufacturing happened in the second part of the planning period (disposal happen at arrival), and the remanufacturing rate was constrained by the demand rate (disposal of serviceable products to control inventory). Our contribution to literature was showed in two cases; usage the infant mortality mode to describe returned products, and simplified the optimal control model by using a different approach to achieve constraints. The explicit solution was realized using the Pontryagin maximum principle. Our numerical results suggest that the control of the inventory level satisfies the demands by combining rates of manufacturing and remanufacturing. Also, remanufacturing being continuous along the planning period is better as it minimizes the total cost.

Resumo em Inglês:

ABSTRACT The format of the efficient frontier is an important measure of technical efficiency; additionally, it determines the type of return to scale verified by the model. The classical Data Envelopment Analysis (DEA) model, CCR (Charnes et al., 1978), assumes constant returns to scale; conversely, the BCC (Banker et al., 1984) model presents a concave downward efficient frontier that presumes variable returns to scale. This study examines how different returns to scale can be revealed in DEA, considering the possibility of the existence of a concave upward efficient frontier. This kind of frontier, not yet explored by the DEA literature, can also represent viable production, seeing that an increase of the inputs causes an increase of the outputs. Considering this, a concave upward efficient frontier presents a variable return to scale, but with different characteristics from those of the concave downward BCC efficient frontier. This proposal is important because it considers the possibility of an efficient frontier that represents different samples of decision-making units (DMUs). An upward curve would better represent DMUs of smaller production scales that have increased marginal productivity but cannot act as efficiently as larger scale units.

Resumo em Inglês:

ABSTRACT This paper shows the results of a research of the application of data envelopment analysis (DEA) together with artificial neural networks (ANN) of higher education institutions in Colombia during the years 2011-2013, for the purpose of evaluating the technical efficiency of Colombian higher education institutions and subsequently carry out predictions, based on a group of management indicators. Information provided by the Ministry of National Education was used as data source. The results show that this two-stage approach provides the DEA with the predictive potential that it otherwise lacks, enhancing its evaluative qualities; this is also evident in the various research papers consulted. The results also show that 50% of the models built have correct classification rates of 64.58% and 58.33% for training and validation datasets, respectively.

Resumo em Inglês:

ABSTRACT Team formation is a key aspect of football, being able to bring sporting and financial results, but also susceptible to great risks. Considering that this problem involves subjective decisions, it also becomes subject to failures. The use of quantitative approach methodologies can overcome such aspects and offer better results for football clubs. In this context, a systematic review was carried out on Operations Research techniques for player selection and formation of football teams, demonstrating the main references and authors of the area. A search on the scientific bases Web of Knowledge, Scopus, and ScienceDirect was carried out during the month of January of 2018, analyzing a total of 1,637 articles. Of these, only 12 were selected for analysis. The research of Boon and Sierksma (2003) was identified as the main reference of the area, being referenced by four other authors. It is highlighted the low number of citations between the papers, as well as the lack of review articles like this one. All these aspects contribute to the relevance of this research, addressing a significant problem in one of the most popular sports in the world and unifying its main references.

Resumo em Inglês:

ABSTRACT The study proposes the development of a framework that can take advantage of the Design and Analysis of Computer Experiments (DACE) more efficiently. The need for rapid product development cycles creates a demand for tools that aid in decision making. One of these tools is Computer Aided Engineering which uses the Finite Element Method that requires a long time to be executed. The philosophy of Design of Experiments and the construction of empirical models have been used together with physical simulations. After a theoretical review, two cases were applied to product development and the results were analyzed. A theoretical framework based on the experience gained from the empirical studies conducted was proposed. Despite the existence of many studies on the subject where mathematical and statistical aspects are explored, there is a lack of studies related to practical and operational issues regarding the application of DACE.

Resumo em Inglês:

ABSTRACT The influence of a principle of preference concentration in the process of decision making in different contexts is discussed here. A procedure exploring the concentration of preferences to derive probabilities and another to derive, with higher generality, Choquet capacities are presented. An important feature of this last procedure is that it derives capacities in a space of criteria only from matrices of probabilities of preference according to each criterion, precluding the effort of directly trying to measure the interactions between them.

Resumo em Inglês:

ABSTRACT The control chart introduced by Shewhart is one of the most important quality control techniques used to detect special causes. Real world data are complicated to interpret since they involve a certain level of uncertainty that may be linked to human subjectivity or measurement device limitations. Fuzzy set theory can deal with such uncertainty and can be applied to traditional control charts. In this work, the values of the quality characteristic are fuzzified by the insertion of uncertainties and transformed into representative values for a better comparison with traditional control charts. The performance of a control chart can be measured by the average run length (ARL) and the extra quadratic loss (EQL). We observed in the present work that the fuzzy control chart has greater efficiency than the traditional control charts. An illustrative example demonstrates the application of the fuzzy control chart for the measurement of the volume contained in milk bags.