Sohrab Kordrostami
Department of Mathematics, Lahijan Branch, Islamic Azad University, Lahijan, Iran
[ 2 ] - Revenue - Profit Measurement in Data Envelopment Analysis with Dynamic Network Structures: A Relational Model
The correlated models are introduced in this article regarding revenue efficiency and profit efficiency in dynamic network production systems. The proposed models are not only applicable in measuring efficiency of divisional, periodical and overall efficiencies, but recognizing the exact sources of inefficiency with respect to revenue and profit efficiencies. Two numerical examples, consisting ...
[ 3 ] - A Method for Solving Super-Efficiency Infeasibility by Adding virtual DMUs with Mean Values
Using super-efficiency, with regard to ranking efficient units, is increasing in DEA. However, this model has some problems such as the infeasibility. Thus, this article studies infeasibility of the input-based super-efficiency model (because of the zero inputs and outputs), and presents a solution by adding two virtual DMUs with mean values (one for inputs and one for outputs). Adding virtual ...
[ 4 ] - Ranking of bank branches with undesirable and fuzzy data: A DEA-based approach
Banks are one of the most important financial sectors in order to the economic development of each country. Certainly, efficiency scores and ranks of banks are significant and effective aspects towards future planning. Sometimes the performance of banks must be measured in the presence of undesirable and vague factors. For these reasons in the current paper a procedure based on data envelopment...
[ 5 ] - COMMON WEIGHTS DETERMINATION IN DATA ENVELOPMENT ANALYSIS
In models of data envelopment analysis (DEA), an optimal set of weights is generally assumed to represent the assessed decision making unit (DMU) in the best light in comparison to all the other DMUs, and so there is an optimal set of weights corresponding to each DMU. The present paper, proposes a three stage method to determine one common set of weights for decision making units. Then, we use...
[ 6 ] - Cost Efficiency of Closed–Loop Supply Chain in the Presence of Dual-Role and Undesirable Factors
Supply chain management is essential for the success of firms and customer satisfaction. In addition, a suitable performance evaluation system is vital to the effective management of the supply chain. Due to the importance of cost management in the supply chain, an approach based on Data Envelopment Analysis (DEA) is proposed in the current study for evaluating the cost efficiency of closed-loo...
[ 7 ] - An Interval Assignment Problem with Multiple Attributes: A DEA-Based Approach
One of the basic combinatorial optimization problems is the assignment problem that deals with assigning jobs to individuals. In traditional assignment problems, n jobs usually assign to n individuals such that the total cost is minimized or the total profit is maximized. However, in numerous real-life applications, various attributes could be considered in assignment problems while data (obj...
[ 8 ] - A Method for Calculating the Marginal Rate in the FDH Model
Trade-off reviews the rate of marginal substitution of inputs and outputs onto the efficient frontier. On the other hand, marginal rates of substitution (MRS) are important quantities for analysts and managers. In this paper, by changing the method of Asmild (2004), an algorithm is found that it can be used to calculate the marginal rate of the free disposal hull (FDH) model.
[ 9 ] - رویکردی نوین برای محاسبه تراکم با ویژگی دسترسی‌پذیری ضعیف خطی خروجی‌های نامطلوب
در سال‌های اخیر، مسئله‌ی تراکم از موضوعات مورد توجه محققان بوده است. هنگامی که افزایش یک یا چند ورودی موجب کاهش یک یا چند خروجی گردد؛ به‌طوریکه سایر ورودی‌ها و خروجی‌ها بدون تغییر باشند (و یا برعکس) اصطلاحاً تراکم رخ داده است. این مفهوم از این جهت در اقتصاد حائز اهمیت است که حذف تراکم باعث کاهش هزینه و افزایش خروجی می‌شود. از طرف دیگر، درفرآیند تولید و یا ارائه‌ی خدمات، بطور معمول، علاوه بر تو...
[ 10 ] - Performance Measurement Techniques In the Presence of Undesirable Products
Performance measurement with undesirable outputs is an important subject in production processes. There are papers in which works can be divided into two groups. First group develops production models which undesirable outputs are considered as inputs and in second one undesirable outputs are modeled as outputs. We provide a comparison between these two groups and we axiomatically show that pro...
[ 11 ] - بهبود عملکرد واحدهای تصمیم‌گیرنده کارا با استفاده از روش تقاطع ابرصفحه‌های سازای مجموعه امکان تولید در تحلیل پوششی داده ها
تحلیل پوششی داده ها (DEA) یک تخمین‌گر است. این تخمین‌گر سعی می کند که یک ارتباط بین ورودی های متعدد و خروجی های متعدد و همچنین تکنولوژی تولید را تخمین بزند. DEA واحدهای تصمیم گیرنده (DMU) را به دو بخش واحدهای کارا و واحدهای ناکارا تقسیم بندی می‌کند. در این صورت واحدهای کارا مرجعی برای واحدهای ناکارا خواهد بود. در مدل‌های سنتیDEA بهبود کارایی تنها برای واحدهای ناکارا صورت می گیرد و واحدهای کارا ...
[ 12 ] - Estimation of cost efficiency for firms in different technologies using data envelopment analysis
Data envelopment analysis (DEA) is a method for evaluating the relative efficiency of a set of firms in a production process. Estimation of cost efficiency is one of the branches of performance evaluation. Cost efficiency evaluates the ability of producing current output with minimum available cost. Now let's assume that there are several groups of firms that operate separately and have differe...
[ 13 ] - Two-Stage Network DEA with Undesirable Outputs: An Application in the Air Transportation in the Spain
In this paper, two non-linear technologies are proposed based on weak disposability definitions: weak disposability with non-uniform abatement factors and new weak disposability. Both technologies are applied to Spanish airport systems and the existing technologies are modified. To remove the computational complexity of non-linear approaches, the linearization methods are proposed. Then, in ord...