Input, Output and Graph Technical Efficiency Measures on Non-Convex FDH Models with Various Scaling Laws: An Integrated Approach Based upon Implicit Enumeration Algorithms

In a recent article, Briec, Kerstens and Vanden Eeckaut (2004) develop a series of nonparametric, deterministic non-convex technologies integrating traditional returns to scale assumptions into the non-convex FDH model. They show, among other things, how the traditional technical input efficiency measure can be analytically derived for these technology specifications. In this paper, we develop a similar approach to calculate output and graph measures of technical efficiency and indicate the general advantage of such solution strategy via enumeration. Furthermore, several analytical formulas are established and some algorithms are proposed relating the three measurement orientations to one another.Data Envelopment Analysis, Free Disposal Hull, technical efficiency

Probabilistic measures of efficiency and the influence of contextual variables in nonparametric production models: an application to agricultural ressearch in Brazil.

In a research institution it is important to identify which management practices have influence on production efficiency. In this paper we assess the statistical significance of contextual variables type, size, financial resources acquisition, intensity of partnerships, processes improvements and management change. The analysis is carried out for the Brazilian Agricultural Research Corporation over the period 1999?2006. The statistical analysis uses a balanced dynamic panel data model. We conclude that only financial resources acquisition is statistically significant. The association with the production process is positive. We also found the two lag inertial components of the conditional FDH to unconditional FDH ratio statistically significant, indicating a 2-year effort to improve efficiency

Returns to scale in convex production technologies

The notion of returns to scale (RTS) is well-established in data envelopment analysis (DEA). In the variable returns-to-scale production technology, the RTS characterization is closely related to other scale characteristics, such as the scale elasticity, most productive scale size (MPSS), and global RTS types indicative of the direction to MPSS. In recent years, a number of alternative production technologies have been developed in the DEA literature. Most of these technologies are polyhedral, and hence are closed and convex sets. Examples include technologies with weakly disposable undesirable outputs, models with weight restrictions and production trade-offs, technologies that include several component production processes, and network DEA models. For most of these technologies, the relationship between RTS and other scale characteristics has remained unexplored. The theoretical results obtained in this paper establish such relationships for a very large class of closed convex technologies, of which polyhedral technologies are an important example

A nonparametric approach to productive efficiency measurement : an application of bootstrap DEA to gold mining

In this dissertation the technical efficiency in gold mining is investigated. To the best available knowledge, this is the first such study on gold mining, whether on a localised (one country) or for a cross-section of countries. Since the work by Farrell (1957), much work has been done using nonparametric methods such as DEA. Although extensions in DEA technique, such as bootstrapping have been available for some time, their use has been limited in comparison with the number of overall DEA studies carried out. In this dissertation both DEA and bootstrap DEA are applied to two gold mining cross sectional samples, one on Zimbabwe consisting of thirty-four mines, and the an international one which also included some Zimbabwean mines which comprise fifty-nine observations.The main reason for carrying out the study is an interest in gold mining in general and its importance to Zimbabwe in particular. As will be noted in Chapter 2, the economic development of Zimbabwe has been linked, to a varying extent over the ages, to its growth of the gold mining sector.The results of the dissertation provide some useful insights into the relative performances of gold mines and also some characteristics of the Zimbabwean gold mining sector. The main results indicate that gold mining is characterised mainly by technical efficiency dominating scale efficiency. This is particular relevant when the Zimbabwean mines are compared with their international counterparts. Zimbabwean mines are found to be relatively technically efficient but less so when overall efficiency is considered. In fact they have the lowest overall efficiency scores in the international sample. The results also indicate that mines from the so-called developed mining economies, Australia, Canada, the US and South Africa are the benchmarks in terms of optimal operations. It is mines from these countries which define the overall efficiency frontier.The results of both the samples highlight potential shortcomings in applying DEA and bootstrap extension to gold mining, both for single country and for cross-country cases. Additionally, there are possibilities, with adequate data, of relating country-specific characteristics to differences in overall efficiency among countries.Finally there are indications that including mineralogical factors such as the recovery rate in the production technology has an effect on technical efficiency. Mines with low recovery rates tend to exhibit comparatively higher technical efficiency. The study does have some limitations, mainly because of lack of data. In particular, there were problems in coming with attributing the contribution of capital services to efficiency with the result that a different measure for the flow of capital services is used for each sample. In addition, the two samples are for different time periods. This limits comparative analysis

Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

On the linearisation of reference technologies for testing returns to scale in FDH models

One of the methods of testing returns to scale (RTS) in data envelopment analysis is based on the use of specially constructed reference technologies. Recently Kerstens and Vanden Eeckaut constructed such technologies for testing RTS in the free disposal bull (FDH) model. The use of these technologies requires solving mixed integer non-linear programming models. In this note we construct equivalent linear models, which have an obvious computational advantage. (C) 2002 Elsevier B.V. All rights reserved