Quantifying cartilage contact stress is paramount to understanding hip osteoarthritis. Discrete element analysis (DEA) is a computationally efficient method to estimate cartilage contact stresses. Previous applications of DEA have underestimated cartilage stresses and yielded unrealistic contact patterns because they assumed constant cartilage thickness and/or concentric joint geometry. The stu...

Data envelopment analysis (DEA) has been recently employed for performance and efficiency evaluation of decision-making units (DMUs) with multiple inputs outputs. Complex internal relations within a DMU required more accurate DEA models than existing classic DEA. In real world applications, shared resources, among stages supply chain, is great interest managers decision makers. Unfair allotment...

supplier selection is a multi-criteria problem. this study proposes a hybrid model for supporting the suppliers’ selection and ranking. this research is a two-stage model designed to fully rank the suppliers where each supplier has multiple inputs and outputs. first, the supplier evaluation problem is formulated by data envelopment analysis (dea), since the regarded decision deals with uncertai...

There are situations that Decision Making Units (DMU’s) have uncertain information and their inputs and outputs cannot alter redially. To this end, this paper combines the rough set theorem (RST) and Data Envelopment Analysis (DEA) and proposes a non-redial Rough-DEA (RDEA) model so called additive rough-DEA model and illustrates the proposed model by a numerical example.  

In this paper, grey system theory and DEA are combined to establish a grey DEA model. In traditional DEA model, Input and output values of decision-making groups are all real numbers and real variables. They are replaced by grey numbers and grey variables in grey DEA model respectively. Using positioning solution method of grey linear programming, we prove the necessary condition for grey effec...

in recent years, the existing competitions between investment companies have been increased largely by entering private investors in capital market. large and powerful companies try to achieve the goals predicted to increase the competition capacity. to analyze the efficiency of investment companies, parametric and non-parametric methods are used. in this research, based on the dissociation pow...

data envelopment analysis (dea) is a technique that uses all collected observations to measure performance. this method presents no data about how to operate on dmu. the present research attempted to study a unit with all its subunits, if the unit is efficient, it means that all its subunits are efficient too and if it is an inefficient, it shows clearly that which one of the subunits makes ine...

in this paper, different input-oriented ratio-based dea (dea-r-i) models are proposed. by presenting the envelopment-additive-enhanced russell model based on the dea-r-i form, each decision making unit is evaluated and its efficiency score is calculated. also, by presenting the central resource allocation model based on the dea-r-i form, a suitable benchmark for all dmus is proposed by solving ...