data envelopment analysis (dea) measures the relative efficiency of a homogenous set of decision-making units (dmus) when multiple inputs and outputs are present. the deabased malmquist productivity index measuring the productivity change of dmus over time has proven itself to be a valid tool to compare group performance. however, in the previous models developed for this purpose, it was suppos...

This paper models the firm’s production process as a system of simultaneous technologies for desirable and undesirable outputs. Desirable outputs are produced by transforming inputs via the conventional transformation function, whereas (consistent with the material balance condition) undesirable outputs are by-produced via the so-called “residual generation technology”. By separating the produc...

in this article, non radial method of dynamic dea with the parallel network structure is presented and is used for calculation of relative efficiency measures when inputs and outputs do not change equally. in this model, dmu divisions under evaluation have been put together in parallel. but its dynamic structure is assumed in series. since in real applications there are undesirable inputs and o...

Data envelopment analysis (DEA) is an effective tool to measure the relative efficiency of decision-making units (DMUs) with multiple inputs and outputs. This study classifies the outputs into desirable and undesirable outputs, and then presents two DEA models, radial and non-radial models, to measure the environment efficiency for DMUs with undesirable outputs. Finally, two proposed DEA models...

In this paper we investigate inputs/outputs estimate in the presence of undesirable factors. We discuss such questions: suppose some outputs (inputs) are undesirable and among a group of decision making units (DMUs) a DMU changes (increases and decreases simultaneously) some of its input (output) levels, how much outputs (inputs) could the unit change such that its efficiency index remains unch...

  In this article, Non radial method of dynamic DEA with the parallel network structure is presented and is used for calculation of relative efficiency measures when inputs and outputs do not change equally. In this model, DMU divisions under evaluation have been put together in parallel. But its dynamic structure is assumed in series. Since in real applications there are undesirable inputs an...

This paper develops slacks-based measure (SBM) and additive SBM (ASBM) to evaluate efficiency of decision making units (DMUs) in a two-stage structure with undesirable outputs and feedback variables from the internal perspective. The SBM model is linearized  for a specific weight and the ASBM model is reformulated as a second order cone program. The target values for all inputs, outputs (both d...

Congestion is one of the main issues in data envelopment analyses which have particular importance. Recently researches about congestion, whether in economic articles or in Operations Research articles in had grown increasingly. Congestion is a wasteful stage of the production process where outputs are reduced due to excessive amount of inputs. In economics, congestion is very important because...