Return-To-Scale (RTS) is a most important topic in DEA. Many methods are not obtained for estimating RTS in DEA, yet. In this paper has developed the Banker-Trall approach to identify situation for RTS for the BCC model "multiplier form" with virtual weight restrictions that are imposed to model by DM judgments. Imposing weight restrictions to DEA models often has created problem of infeasibili...

This study investigates the directional return to scale of biological institutions in the China Science Academy. In the first stage, the input-output indicators provided including staff, budget of studies, SCI articles, high quality articles and graduate education, etc. In the second stage, the method proposed by Yang (2012) was used to analyse directional return to scale and directional conges...

In this paper, a two stages method to determine suitable benchmark and return scale of the decision making units set is presented. At first, all of the efficient reference set in no radial data envelopment analysis (DEA) based on linear programming is found. first, RAM model is introduced and units is investigated using this model, then, to run the given algorithm below steps is performed. At t...

An infinite word has the property Rm if every factor has exactly m return words. Vuillon showed that R2 characterizes Sturmian words. We prove that a word satisfies Rm if its complexity function is (m − 1)n + 1 and if it contains no weak bispecial factor. These conditions are necessary for m = 3, whereas for m = 4 the complexity function need not be 3n + 1. A new class of words satisfying Rm is...

In this paper we present a threshold model to describe the phenomena of zero return enhancement that is present in Australian Stock Exchange data. We examine the intraday behaviour of the ASX data and construct a new measure for the market activity using principal component analysis. We use this measure to create a business time scale that keeps the level of zero return enhancement constant thr...