Fuzzy efficiency evaluation in relational network data envelopment analysis: application in gas refineries

Abstract In contrast to classical data envelopment analysis (DEA), network DEA has attention the internal structure of a production system and reveals relationship between efficiency efficiencies processes. However, flexibility weights need for crisp input output in evaluation process are two major shortcomings models. This paper presents common approach relational model fuzzy environment measure component The proposed first finds upper bounds on given cut level then it determines set (CSW) all decision-making units (DMUs). Hence, processes systems DMUs obtained based resulting CSW. developed illustrated with numerical example. results confirm that affects over scores complete ranking DMUs. applicability is by performance gas refineries Iran.