This paper adopts two mathematical approaches, data envelopment analysis (DEA) and grey relation analysis (GRA) to measure DEA efficiency using the sample of 69 listed US internet companies. A total of 40 indicators were initially selected for the efficiency evaluation, with 21 related to DEA-input indicators and 19 to DEAoutput indicators. Eight representative indicators selected using GRA are...

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...

The spectroscopic and electrochemical properties of a series of four RuII polypyridyl complexes are reported. Compounds of the form [Ru(dmb)x(dea)3-x] (x ) 0-3), where dmb is 4,4′-dimethyl-2,2′-bipyridine and dea is 4,4′-bis(diethylamino)-2,2′-bipyridine, have been prepared and studied using static and time-resolved electronic and vibrational spectroscopies as a prelude to femtosecond spectrosc...

An algorithm stral:egy is proposed for use with the assurance region (AR) approach in data envelopment analysis (DEA). The strategy addressed in this study characterizes and cla.5sifies all decision making units (DMUs) into several subsets, using the revised simplex method of linear programming. Then, each DMU subset is solved by a different algorithm. Experimental studies consisting of randoml...

In many data envelopment analysis (DEA) applications, the analyst always confronts the difficulty that the selected data set is not suitable to apply traditional DEA models for their poor discrimination. This paper presents an approach using Shannon’s entropy to improve the discrimination of traditional DEA models. In this approach, DEA efficiencies are first calculated for all possible variabl...