ABSTRACT Parametric DEA models presume a functional form for the efficiency frontier and are used for resource redistribution. Parabolic DEA is a particular case of these models used to redistribute a single input in Variable Returns to Scale scenarios. In this study, we extend this model to redistribute multiple inputs simultaneously, ensuring that all DMUs will become extreme efficient after redistribution maintaining their outputs. The proposed model is a single multi-objective Linear Programming Problem (PPL) which provides a single optimal solution. To solve this model, two approaches are used, the Weighted Sum of the Objective Functions and the Separation of Variables. Two numerical examples considering single and multiple outputs are used and the results obtained are identical for the two approaches. scenarios study simultaneously multiobjective multi objective PPL (PPL solution Variables

Resumo As bibliotecas universitárias prestam um importante serviço à sociedade, contribuindo para difundir o conhecimento e cultivar novos talentos dentro do ambiente acadêmico. Neste estudo, a revisão da literatura sobre avaliação de eficiência no contexto das bibliotecas universitárias é o principal objetivo. Foram adotadas como referência as bases de dados Web of Science e Scopus para a busca de trabalhos no contexto acima mencionado e para a identificação das metodologias utilizadas e perspectivas estabelecidas pelos diferentes autores. Realizou-se uma pesquisa complementar na base Google Scholar para a obtenção de outros artigos. Em suma, foram selecionados 34 trabalhos para compor o núcleo de publicações analisadas. Como resultado, observou-se que cerca de 90% dos artigos utilizam a Análise de Envoltória de Dados para avaliar a eficiência das bibliotecas universitárias, tendo sido identificadas outras metodologias com a mesma proposta. Além disso, analisaram-se as variáveis utilizadas nessas publicações, contribuindo para o mapeamento dos principais inputs e outputs que afetam diretamente os serviços prestados pelas bibliotecas universitárias. Ademais, foram consideradas outras características, tais como o arranjo temporal das publicações e os países com a maior produção de artigos. Por fim, foram sugeridas pesquisas adicionais com base nos resultados deste estudo.

Abstract University libraries provide an important service to society, contributing to spread knowledge and cultivating new talents in the academic environment. The main objective of this article is to perform a review of the literature on efficiency assessments in the context of university libraries. The databases Web of Science and Scopus were adopted as reference to search for papers in the aforementioned context and identify the methodologies used and perspectives set out by different authors. A complementary search was also made on Google Scholar to obtain additional articles. In sum, 34 papers were found to compose the core of analyzed publications. As result, we observed that nearly 90% of the papers use Data Envelopment Analysis to assess the efficiency of university libraries and other methodologies with the same proposal were identified. Moreover, the variables used in these publications were analyzed, contributing to the mapping of main inputs and outputs that directly affect the services of university libraries. Furthermore, other characteristics were also considered, such as: temporal placement of publications and countries with the largest production of papers. Finally, based on the results of this study, further researches are suggested.

El Análisis Envolvente de Datos es un enfoque no paramétrico para la evaluación de la eficiencia de las llamadas DMUs - Unidades Tomadores de Decisión, teniendo en cuenta múltiples entradas y salidas. Para cada DMU ineficiente, se proporciona una meta que está constituida por los niveles de entradas o salidas que deben ser alcanzados para que la DMU ineficiente se vuelva eficiente. Sin embargo, los modelos multiobjetivo, llamados modelos MORO (del ingles Multiobjective model for Ratio Optimization) proporcionan un conjunto de metas para DMU ineficientes, lo que ofrece alternativas de las cuales el decisor puede elegir. En este trabajo se ha propuesto una extensión de los modelos MORO para tener en cuenta las variables no-discrecionales, es decir, variables que no se pueden controlar. Se presenta un ejemplo numérico para ilustrar el modelo multiobjetivo propuesto. También se discuten las características de este modelo, así como las ventajas de ofrecer un conjunto de metas para la DMU ineficientes cuando hay variables no discrecionales en el conjunto de datos.

Data Envelopment Analysis is a non-parametrical approach for efficiency evaluation of so-called DMUs (Decision Making Units) and takes into account multiple inputs and outputs. For each inefficient DMU, a target is provided which is constituted by the inputs or outputs levels that are to be attained for the inefficient DMU to become efficient. However, multiobjective models, known as MORO (Multiobjective Model for Ratio Optimization) provide a set of targets for inefficient DMU, which provides alternatives among which the decision-maker can choose. In this paper, we proposed an extension of the MORO models to take into account non-discretionary variables, i.e., variables that cannot be controlled. We present a numerical example to illustrate the proposed multiobjective model. We also discuss the characteristics of this model, as well as the advantages of offering a set of targets for the inefficient DMUs when there are non-discretionary variables in the data set.

The increase of the air transportation sector competition in recent years has changed this market dynamics, leading airlines to seek new strategies to ensure their position. This article aims to analyze the performance of Brazilian air carriers regarding their operational management, after the consolidation of the changes arising from the deregulation of the sector, in the year 2005. The analysis of the companies' efficiency in the year 2005 is done by comparing the results obtained with Data Envelopment Analysis model and with efficiency index based on the multiobjective model MCDEA-BCC, developed in this study from the Li and Reeves' MCDEA model. This project included a segmentation of the companies in clusters and benchmark, indicating the best managerial practices in the air sector.

El aumento creciente de la competitividad del sector de transporte aéreo en los últimos años provocó un cambio en la dinámica del mercado, lo que ha llevado a las compañías aéreas a buscar nuevas estrategias para garantizar sus posiciones en el mercado. Este artículo tiene por objetivo hacer un análisis del desempeño de las compañías aéreas brasileñas, con relación a su gestión operacional después de la consolidación de los cambios resultantes de la liberalización del sector en el año 2005. La eficiencia de las empresas aéreas se calcula a través de la comparación de los resultados obtenidos con el modelo del Análisis Envolvente de Datos (DEA) clásico con los índices de eficiencia calculados con base en el modelo multiobjetivo MCDEA-BCC, desarrollado para este estudio a partir del modelo MCDEA de Li e Reeves. Además este trabajo incluye la segmentación de las empresas en agrupamientos y la identificación de benchmarks, en la que se indican las compañías con las mejores prácticas gerenciales del sector aéreo.

In recent years, a lot of work has been done dealing with alternative performance rankings for the Olympic Games. Almost all of these works use Data Envelopment Analysis (DEA). Generally speaking, those works can be divided into two categories: Pure rankings with unitary input models and relative rankings with classical DEA models; both output oriented. In this paper we introduce an approach taking into account the number of athletes as a proxy to the country investment in sports. This number is an input for a DEA model, and the other input is the population of the country. We have three outputs,the number of gold, silver and bronze medals earned by each country. Contrary to the usual approach in the literature, our model is not output oriented. It is a non-radial DEA model oriented to the "number of athletes" input, as our goal is not a countries' ranking. We intend to analyse whether the number of athletes competing for each country accords with the number of won medals. For this analysis, we compare eachcountry with its benchmarks. The Decision Making Units (DMU) are all the countries participating in the Beijing Olympic Games, including those that did not earn a single medal. We use a BCC model and we compare each DMU's target with the number of athletes who have won, at least one medal.

The main goal of this paper is to provide a preliminary analysis of the code share agreement involving Varig and Tam. The data used is concerned about Rio de Janeiro-São Paulo air shuttle, one of the main Brazilian domestic routes. We use Data Envelopment Analysis (DEA) with double frontier approach, to compare the conditions in October 2002 (before the agreement) and April 2003 (after the agreement). As DEA models are comparative ones, we need to extend the analysis to all the other companies flying in the same route. From the results we can say that the agreement did not improve the service provided to passengers

El objetivo de este artículo es promover un primer análisis de las consecuencias para el pasajero del acuerdo de cooperación entre las empresas aéreas Varig y Tam, en una de las principales rutas nacionales. Se utiliza la técnica del Análisis Envolvente de Datos (Data Envelopment Analysis - DEA) con dos fronteras (ópticas del pasajero y del empresario, o frontera tradicional y frontera invertida), para comparar la situación en octubre de 2002 (anterior al acuerdo) y abril de 2003 (posterior). Como los modelos DEA son comparativos, se necesita incluir en el análisis todas las otras opciones (otras compañías aéreas) de conexiones en la ruta Río de Janeiro-Sao Paulo. Los resultados muestran que dicho acuerdo no beneficia a los pasajeros