data envelopment analysis (dea) is a method for measuring the efficiency of peer decision making units (dmus) which uses a set of inputs to produce a set of outputs. in some cases, dmus have a two-stage structure, in which the first stage utilizes inputs to produce outputs used as the inputs of the second stage to produce final outputs. one important issue in two-stage dea is the sensitivity of...

This article aims to investigate the location of dry ports by providing a two-stage GIS-optimization model. At the first stage, the appropriate points for establishing dry ports were identified using GIS and hierarchical analysis process; then, the suitable points were introduced as the potential points to the second stage model. At the second stage, by providing a multi-objective integer model...

the development of optimization and mathematical models for closed loop supply chain (clsc) design has attracted considerable interest over the past decades. however, the uncertainties that are inherent in the network design and the complex interactions among various uncertain parameters are challenging the capabilities of the developed tools. the aim of this paper, therefore, is to propose a n...

In this paper, a brief summary of the heuristic methods, single-stage optimization methods, time-phased optimization methods, artificial intelligence (AI) techniques and iterative improvement methods are presented. Finally, some of the important characteristics of network programming methods and their strengths and weaknesses are identified and compared. Key-words Heuristic Methods, Single-Stag...

We consider flowshop environments that consist of multiple stages and multiple machines in each stage. The flowshops are flexible in the sense that a task within a stage can be processed by any of the machines in the stage. We refer to this design as the hybrid flowshop. Our objective is to schedule a set of n jobs so as to minimize makespan. The problem is NP-complete even in the case of a sin...

Fleet planning is a process of strategic importance for an airline. Airlines have a tendency to match their capacities and passenger demand for corresponding market conditions, which has a direct impact on airline profitability and costs. It is necessary to consider many different factors in order to make a good fleet plan. This paper proposes the sequential two-stage model for fleet planning. ...