Sharif University of Technology Scientia Iranica 1026-3098 25 1 2018 02 01 The NDEA–MOP Model in the Presence of Negative Data Using Fuzzy Method 398 409 4413 10.24200/sci.2017.4413 EN Kianoosh Kianfar Department of Industrial Engineering, Science and Research branch, Islamic Azad University, Tehran, Iran. Mahnaz Ahadzadeh Namin Department of Mathematics, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran Akbar Alam Tabriz Department of Management, Shahid Beheshti University, Tehran, Iran Esmaeil Najafi Department of Industrial Engineering, Science and Research branch, Islamic Azad University, Tehran, Iran Farhad Hosseinzadeh Lotfi Department of Mathematics, Science and Research branch, Islamic Azad University, Tehran, Iran Journal Article 2016 02 13 In this study, the multi-objective programming (MOP) method was used to solve network DEA (NDEA) models with assumption that, negative data is considered for the proposed NDEA model which consists of semi-negative and semi-positive input and output. At first, two stage and then k stage production models were formulated with consideration of negative data. In the multi-objective programming, two separate objective functions including the divisional efficiencies and the overall efficiency of the organization are modeled.  In comparison to conventional DEA with negative data, the advantage of the proposed NDEA models is consideration of intermediate processes and products, in order to calculate the organization's overall efficiency. However, in conventional DEA, sub-stages of the organizations are neglected. To measure the efficiencies of an organization regarding interactive internal process, two case studies were investigated by application of the NDEA-MOP method with negative data. Case study 1 is focused on units with two stages having semi-negative and semi-positive indexes. In case study 2, units with three stages are evaluated. These units also have semi-negative and semi-positive indexes. The overall efficiency of each unit is calculated using the proposed models. Fuzzy approach as a solution procedure is applied. https://scientiairanica.sharif.edu/article_4413_83c3c58afe2e36df0e3831c996a1c83d.pdf