A New Approach to Reducing Search Space and Increasing Efficiency in Simulation Optimization Problems via the Fuzzy-DEA-BCC

The development of discrete-event simulation software was one of the most successful interfaces in operational research with computation. As a result, research has been focused on the development of new methods and algorithms with the purpose of increasing simulation optimization efficiency and reliability. This study aims to define optimum variation intervals for each decision variable through a proposed approach which combines the data envelopment analysis with the Fuzzy logic (Fuzzy-DEA-BCC), seeking to improve the decision-making units’ distinction in the face of uncertainty. In this study, Taguchi’s orthogonal arrays were used to generate the necessary quantity of DMUs, and the output variables were generated by the simulation. Two study objects were utilized as examples of mono- and multiobjective problems. Results confirmed the reliability and applicability of the proposed method, as it enabled a significant reduction in search space and computational demand when compared to conventional simulation optimization techniques

Benchmarking with network DEA in a fuzzy environment

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Benchmarking is a powerful and thriving tool to enhance the performance and profitabilities of organizations in business engineering. Though performance benchmarking has practically and theoretically developed in distinct fields such as banking, education, health and so on, supply chain benchmarking across multiple echelons that includes certain characteristics such as intermediate measure differs from other fields. In spite of incremental benchmarking activities in practice, there is the dearth of a unified and effective guideline for benchmarking in organizations. Amongst the benchmarking tools, data envelopment analysis (DEA) as a non-parametric technique has been widely used to measure the relative efficiency of firms. However, the conventional DEA models that are bearing out precise input and output data turn out to be incapable of dealing with uncertainty, particularly when the gathered data encompasses natural language expressions and human judgements. In this paper, we present an imprecise network benchmarking for the purpose of reflecting the human judgments with the fuzzy values rather than precise numbers. In doing so, we propose the fuzzy network DEA models to compute the overall system scale and technical efficiency of those organizations whose internal structure is known. A classification scheme is presented based upon their fuzzy efficiencies with the aim of classifying the organizations. We finally provide a case study of the airport and travel sector to elucidate the details of the proposed method in this study

An Adjustable Fuzzy Chance-Constrained Network DEA Approach with Application to Ranking Investment Firms

This paper presents a novel approach for performance appraisal and ranking of decision-making units (DMUs) with two-stage network structure in the presence of imprecise and vague data. In order to achieve this goal, two-stage data envelopment analysis (DEA) model, adjustable possibilistic programming (APP), and chance-constrained programming (CCP) are applied to propose the new fuzzy network data envelopment analysis (FNDEA) approach. The main advantages of the proposed FNDEA approach can be summarized as follows: linearity of the proposed FNDEA models, unique efficiency decomposing under ambiguity, capability to extending for other network structures. Moreover, FNDEA approach can be applied for ranking of two-stage DMUs under fuzzy environment in three stages: 1) solving the proposed FNDEA model for all optimistic-pessimistic viewpoints and confidence levels, 2) then plotting the results and drawing the surface of all efficiency scores, 3) and finally calculate the volume of the three-dimensional shape in below the efficiency surface. This volume can be as ranking criterion. Remarkably, the presented fuzzy network DEA approach is implemented for performance appraisal and ranking of investment firms (IFs) with two-stage processes including operational and portfolio management process. Illustrative results of the real-life case study show that the proposed approach is effective and practically very useful

Fuzzy Efficiency Measures in Data Envelopment Analysis Using Lexicographic Multiobjective Approach

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.There is an extensive literature in data envelopment analysis (DEA) aimed at evaluating the relative efficiency of a set of decision-making units (DMUs). Conventional DEA models use definite and precise data while real-life problems often consist of some ambiguous and vague information, such as linguistic terms. Fuzzy sets theory can be effectively used to handle data ambiguity and vagueness in DEA problems. This paper proposes a novel fully fuzzified DEA (FFDEA) approach where, in addition to input and output data, all the variables are considered fuzzy, including the resulting efficiency scores. A lexicographic multi-objective linear programming (MOLP) approach is suggested to solve the fuzzy models proposed in this study. The contribution of this paper is fivefold: (1) both fuzzy Constant and Variable Returns to Scale models are considered to measure fuzzy efficiencies; (2) a classification scheme for DMUs, based on their fuzzy efficiencies, is defined with three categories; (3) fuzzy input and output targets are computed for improving the inefficient DMUs; (4) a super-efficiency FFDEA model is also formulated to rank the fuzzy efficient DMUs; and (5) the proposed approach is illustrated, and compared with existing methods, using a dataset from the literature

Aplicação do Método Data Envelopment Analysis na Marinha Portuguesa

A Marinha não possui meios financeiros próprios e depende de fontes de financiamento público que sejam suficientes para colmatar as despesas efetuadas. O financiamento público tem de ser usado para colmatar necessidades públicas, tornandose importantíssimo conseguir identificar pontos onde melhorar a utilização de recursos. De forma a obter melhores resultados com menor ou igual custo é necessário aplicar métodos de avaliação de desempenho no uso dos recursos públicos. O objetivo desta dissertação de mestrado é medir a eficiência da gestão de manutenção das viaturas atribuídas a Comandantes, Diretores, Chefes e ao Protocolo da Marinha, designadas por viaturas de Tipo-D. A abordagem seguida neste estudo tem por base o método da Análise Envoltória de Dados juntamente com a Análise Exploratória de Dados. Os problemas de avaliação de desempenho nas Forças Armadas Nacionais têm vindo a ser abordados ao longo dos tempos através das mais diversas técnicas de gestão, mas curiosamente, nunca usando a Análise Envoltória de Dados, que já por diversas vezes foi implementada a nível internacional e comprovada como uma mais valia para organizações públicas e privadas. Desta forma investigou-se os recursos usados (inputs) na manutenção dos veículos e os resultados (outputs) obtidos com a sua utilização. Os resultados demonstram que a frota automóvel da marinha está envelhecida, que os custos de manutenção têm vindo a aumentar nos últimos anos e que a manutenção na Marinha opera em baixa escala. Fatores como a idade, marca e acidentes influenciam a eficiência da manutenção. Adicionalmente a manutenção em oficina interna apresenta melhores eficiências, no entanto, os contratos de locação financeira também atingem boas eficiências. Os resultados sugerem que a Marinha tem de assegurar a modernização e renovação da sua frota automóvel e por outro lado decidir pela aposta na capacidade interna de gestão da manutenção ou pela mudança para contratos de locação, permitindo a libertação de recursos para as competências essências da MarinhaThe Navy doesn`t have its own financial means and depends on public funding sources to cover the expenses incurred. Public funding must be used to meet public needs, making it important to identify points where to improve the use of resources. In order to obtain better results at less or equal cost, it is necessary to apply performance evaluation methods in the usage of public resources. The scope of this master's thesis is to assess the maintenance management operations efficiency of vehicles assigned to Commanders, Directors, Chiefs and the Navy Protocol, designated by Type-D vehicles. The approach followed in this study is based on the Data Envelopment Analysis method together with Exploratory Data Analysis. The problems ofperformance evaluation in the Portuguese Armed Forces have been approached multiple times through the most diverse management techniques, but interestingly, never using Data Envelopment Analysis, which has already been implemented internationally on several occasions and proven as an asset for public and private organizations. With that in mind, the resources used (inputs) on vehicle maintenance and the results (outputs) obtained by their use were investigated. The results show that the navy car fleet is aged, that maintenance costs have been increasing in recent years and that maintenance in the Navy operates on a small scale. Factors such as age, brand and accidents influence maintenance efficiency. In addition, a comparison between in-house maintenance and leasing contracts revealed that in-house maintenance has better efficiencies, however, leasing contracts also achieve considerably good efficiencies. The results suggest that the Navy has to ensure the modernization and renewal of its automobile fleet and, on the other hand, decide to invest in internal maintenance management capacity or to switch to leasing contracts, allowing the release of resources for the essential competences of the Navy

Efficience de la recherche dans les écoles de gestion au Canada : modélisation par des approches paramétriques et non-paramétriques

La production des connaissances revêt une grande valeur pour les gouvernements, les universités et les chercheurs. Pour ces derniers, aujourd’hui plus que jamais, la recherche prend de plus en plus d’importance dans leurs portefeuilles d’activités. Plusieurs facteurs motivent cette nouvelle tendance, notamment l’adoption, dans plusieurs pays, de systèmes de financement de la recherche axée sur la productivité, la concurrence en matière de recherche qui est devenue mondiale, la prolifération des outils uniformisés de mesure de l’excellence scientifique, et l’importance de la performance et de la productivité en recherche dans la réussite de la trajectoire de carrière des chercheurs. Cependant, la performance des chercheurs universitaires est très variable, tant entre les disciplines qu’au sein d’une même discipline. Ces constats renforcent la pertinence de questionner l’allocation et la gestion des ressources dans le domaine de la recherche universitaire. La présente étude s’attaque à cette problématique dans le cadre spécifique de la recherche dans les Écoles de gestion au Canada. Son objectif général est, d’une part, de dresser un portrait détaillé de l’avancement des connaissances sur le concept de l’efficience de la recherche académique et d’identifier les principaux jalons qui ont marqué son évolution au cours des deux dernières décennies et, d’autre part, d’évaluer l’efficience en matière de publications et de citations des chercheurs dans les Écoles de gestion au Canada et d’identifier les déterminants susceptibles d’expliquer les écarts d’efficience entre eux. La thèse est structurée en trois articles. Le premier article a préconisé la méthode de la revue systématique de la littérature et celle du « vote counting » pour édifier un cadre conceptuel intégrateur des intrants, des extrants et des déterminants de l’efficience de la recherche académique. Il a également permis d’identifier plusieurs opportunités de recherche pour contribuer à l’avancement des connaissances dans ce champ d’étude. Le deuxième article a utilisé une nouvelle méthode, « The Reference Publication Year Spectroscopy » pour étudier en profondeur le concept de l’efficience de la recherche académique en identifiant ses racines historiques ainsi que les contributions qui ont conditionné son évolution. Ces deux premiers articles ont permis de satisfaire à la première partie de l’objectif général de cette recherche : « dresser un portrait détaillé de l’avancement des connaissances sur le concept de l’efficience de la recherche académique et d’identifier les principaux jalons qui ont marqué son évolution au cours des deux dernières décennies ». Tirant profit des constats et des contributions potentielles à l’avancement des connaissances identifiés dans les deux premiers articles, le troisième article de la thèse a estimé des frontières paramétriques et nonparamétriques de l’efficience en matière de publications et de citations des chercheurs dans huit disciplines de recherche dans les Écoles de gestion au Canada. Il a également identifié plusieurs déterminants des écarts d’efficience entre les chercheurs affiliés à ces Écoles. Entre autres, les résultats de ce troisième article ont montré que les niveaux d’efficience diffèrent d’une manière significative d’un champ disciplinaire à un autre, et au sein même des champs disciplinaires, et que l'accréditation AACSB, l'affiliation à des universités prestigieuses, la taille de l'institution, les sources de financement et la séniorité sont positivement associées à des niveaux d’efficience élevés. Les résultats des trois articles ont permis de suggérer quelques pistes de réflexion et d’intervention pouvant améliorer l’efficience de la recherche académique des chercheurs en général, et de ceux affiliés aux Écoles de gestion au Canada, en particulier.The production of knowledge is of great importance to governments, universities and researchers. For the latter, today more than ever, research is becoming more and more important in their portfolios of activities. A number of factors are driving this new trend, including the introduction of productivity-driven research funding systems in a number of countries, global competition for research, the proliferation of standardized tools for assessing scientific excellence, and the importance of research performance and productivity in researchers’ career path success. However, the performance of university researchers varies greatly between disciplines and within the same discipline. These findings reinforce the relevance of questioning the allocation and management of resources in the field of university research. This study addresses this issue in the specific context of research in Canadian Business Schools. Its aims, on the one hand, to draw a detailed portrait of the advancement of knowledge on the concept of the efficiency of academic research and to identify the main milestones that have marked its evolution over the last two decades and, on the other hand, to evaluate the efficiency of academic research of Canadian Business Schools’ scholars and to identify the determinants that may explain the differences in efficiency between them. The thesis allowed the production of three articles. The first one used the systematic review of the literature and the method of vote counting to build an integrative conceptual framework of inputs, outputs, and determinants of the efficiency of academic research. It has also identified several research opportunities to contribute to the advancement of knowledge in this field of study. The second article used a new method, The Reference Publication Year Spectroscopy, to study in depth the concept of the efficiency of academic research by identifying its historical roots as well as the contributions that marked its evolution. These first two articles made it possible to satisfy the first part of the general objective of this research: “to draw a detailed portrait of the advancement of knowledge on the concept of the efficiency of academic research and to identify the main milestones that have marked its evolution over the last two decades”. Taking advantage of the findings and potential contributions to the advancement of knowledge identified in the first two articles, the third article estimated parametric and non-parametric frontiers of efficiency of scholars’ publications and citations in eight research disciplines in Canadian Business schools. It also allowed to identify several levers of efficiency gaps among researchers affiliated with these schools. Among other things, the results of this third article showed that efficiency scores differ significantly from one disciplinary field to another, and even within disciplinary fields, and that AACSB accreditation, affiliation to prestigious universities, size of institution, sources of funding and seniority are positively associated with high levels of efficiency. The findings of the three articles devised some lines of action that might improve the efficiency of academic research for researchers in general and those affiliated with Canadian Business schools, in particular