Journal of Operational Research in its Applications
Year:2011 | Volume:8 | Issue:3 (30)|Papers Count:8

In recent years, the vast development of information technology had significant impacts on the methods of managing supply chain systems. One of items that had been under such influence is supply chain configuration that can be built in various ways. The increase in the number of demands to get into the system in one way and the expansion of communication by newly developed technologies from other way the selection of Supply chain members had made very difficult. In this article, researchers have employed simulated annealing approach for solving a model originally was developed by Graves.

Robust parameter design is an engineering methodology intended as a cost-effective approach for improving the quality of products and processes. The goal of parameter design is to choose the levels of the control variables that optimize a defined quality characteristic. An essential component of robust parameter design involves the assumption of well estimated models for the process mean and variance. Traditionally, the modeling of the mean and variance has been done parametrically. It is often the case, particularly when modeling the variance, that nonparametric techniques are more appropriate due to the nature of the curvature in the underlying function. In this paper, while the optimizing wool dying process in textile industry though two parametric and nonparametric methods of optimization, we comparison obtained results.

With entrance Telecommunication Company to the shares marketing for the charge to know efficiency of telecommunication are essential. This research is with the aim of investigation the performance of Tele Communication Company in provinces by of through them noticing the financial indexes ended to 1387. First of all the descriptive statistics related to each index and the country thirty provinces were taken in order that the position and situation of each index can be presented in comparative. In the next stage the Data Envelopment Analysis was used for priority of index and provinces so it would priorities each index and province on the basic of their means. In the end, researcher while comprehensive presentation of result founding, the mentioned cases were gathered, the discussion and comparison, practical offers and suggestions related to more attention the small scale telecommunication provinces in furthers programming.

In some of the production activities, besides producing desirable outputs, there exist some undesirable outputs like emissions of harmful substances in air, production wastage and other detrimental side effects such as noise. Therefore, modeling undesirable outputs has attracted considerable attention among production economists. The current study reviews the recently developed techniques in activity analysis with an especial focus on introducing axiomatic approaches.

Suppliers are a vital part to each organization which can have so many effects on organization performance. Because of such various effects, rechecking supplier selection methods comes to be necessary. Total Cost of Ownership (TCO), is one of the new methods which prepares necessary information related to supplier selection and evaluation topic. This research aims to select and evaluate automotive parts suppliers using TCO concept. Here DEA approach based on TCO multiple criteria is used to evaluate suppliers’ performance. Information on automotive parts corporations based on strategic approach which is capable in decreasing Total cost of ownership to each company, is analyzed. In fact, DEA selected the most efficient suppliers owning the least total cost and presents some modus for inefficient suppliers in order to increase their efficiency to reach the efficiency frontier.

The Multiple Traveling Salesman Problem (MTSP) is one of the most famous combinatorial optimization problems in which m>1 traveling salesmen simultaneously start to move from the node in the name of depot and come back to it after visiting n>m customers so that each customer is visited only once by a salesman. The objective is to minimize the total route visited by all the salesmen. In this paper, a modified elite ant colony is applied for this problem differenced in encouragement coefficient of the best route. This coefficient leads that the algorithm has more ability for escaping from local optimum points, and can yield better solutions. Experimental conclusions on standard benchmarks clearly show performance of the new algorithm compared with other meta-heuristic algorithms.

The congestion economic concept has recently discussed in DEA (data envelopment analysis) studied and congestion has obtained with different approaches. Also determining of wide congestion and to measure degree of wide congestion is introduced [12]. We know that inefficiency of a Decision Making Unit (DMU) is necessary condition in order to congestion present, also for determining congestion of DMU, first we obtain its projection on frontier efficiency and then we evaluate its projection congestion. Now, it arise a logical question: whether we able project an inefficient DMU on frontier efficient, in practically? Therefore, for answer this question we suggested layer-congestion idea. In other words, layer-congestion is worthwhile when a DMU cannot remove its inefficiency. This paper introduced layer congestion in order to remove congestion of evaluated unit, and it measure degree of wide congestion in different layers.

Sensitivity analysis of returns to scale are classified by the DEA linear programming has been studied. Seiford at al. [1] were studied the sensitivity analysis of returns to scale based on two conditions. In this paper, the sensitivity analysis are discussed in general. For this purpose, the models are presented, which models the type of returns to scale and the stability of the classification of returns to scale is determined. Output changes on the input orientation of the CCR model and input changes the output orientation of the CCR model is considered. In this paper, the sensitivity analysis of CCR efficient DMU that are inefficient will be considered.