چكيده به لاتين
Transportation is one of the important issue in development of countries and a linking different sector of economy. Therefore, evaluating the efficiency of the transportation industry, especially air transport, as the fastest and most expensive one, has particular importance in today’s competitive world. The purpose of this research is to evaluate the efficiency of airlines. Data Envelopment Analysis (DEA) method, was chosen as one of the most popular method to evaluate the efficiency. DEA is a math programming method for evaluating the efficiency of the same Decision Making Units (DMUs) with several inputs and outputs, in which a number of units are introduced as efficient and with their help, form efficient frontier as a criteria for evaluating other units. Network DEA models have been developed by taking in to account different sections and stages of organizations in the calculation of efficiency in recent years. Network DEA can identify the source of inefficiency. In standard DEA, the under evaluation DMU, is depicted on the efficient frontier by decreasing inputs or increasing outputs, however, in real-world situations, organizations face with undesirable outputs that are needed to be reduced. Standard DEA models are not capable of reducing undesirable outputs. Regarding the literature on undesirable outputs, the ways for incorporating undesirable outputs in DEA models are divided into two general categories of direct and indirect methods. Direct methods use the original data of undesirable output along with the modification of the assumption related to the structure of the technology set. On the contrary, indirect methods change the original undesirable output data use a strictly decreasing function in standard DEA models. Furthermore, DEA models use certain data but the values of the parameters are uncertain in the real world. When historical data is not sufficient and reliable and expert individuals are also not available, we can use of "Robust DEA" as an approach to dealing with uncertainty. In this research, Slack-Based Measure (SBM) mode as the newest DEA model which simultaneously increase output and reduce input, was chosen as the base model. two new model called "Robust Network SBM model with Strong Undesirable Output Disposability" and "Robust SBM model with Strong Undesirable Output Disposability" is presented, Which is a kind of development of the robust DEA models. 14 Iranian airlines efficiency was calculated and ranked using it. According to results of the solving "Network SBM model with Strong Undesirable Output Disposability", before making robust models; Pooya Air, Atrak, Taban and Mahan are efficient units. Also the results of solving "SBM model with Strong Undesirable Output Disposability" were showed that Pooya Air, Atrak, Taban, Caspian and Mahan are efficient. while using two new robust model, all efficiency values are reduced and also the efficiency scores of all airlines is less than one.
