the existing directional distance function-based approaches, the proposed method is units-invariant even in case … distance function method for handling asymmetrically both desirable and undesirable outputs in the assessment process. Unlike … Envelopment Analysis) which fail to express the true production process. In the present paper we develop a generalized directional …

The directional distance function model is a generalization of the radial model in data envelopment analysis (DEA). The … directional distance function model is appropriate for dealing with cases where undesirable outputs exist. However, it is not a … models. Based on normalized data, a units-invariant efficiency measure for the directional distance function model is defined. …

This paper proposes a conditional directional distance function model in order to examine the link between regional …

empirical model for investigating such a relationship. By modifying a conditional directional distance function model, we …