Fuzzy Goal Programming

<span lang="EN-GB">This research presents a mathematical model for performance-based budgeting and combines it with rolling budget for increased flexibility. The model has been designed by Chebyshev's goal programming technique with fuzzy approach. The parameters or coefficients of the model are derived by measuring the productivity of the organizations considering eight criteria. Data for calculating productivity indicators were collected from gas refineries of Iran in 2011–2015 and analysed by Excel and GAMS software. Then, the model was tested for determining the 2016 budget of those refineries. The model was solved by LINGO software by linking it to Excel. The solution of the model reduced 0.68% of the total refinery's budget compared with the actual budgets for 2016, which is higher than the annual budget of some of the companies in this group.</span>

Sustainable supply chain has become an integral part of the corporate strategy. In this paper, a real case study of the natural gas supply chain has been investigated. Using concepts related to natural gas industry and the relations among the compo-nents of gas and oil wells, refineries, storage tanks, dispatching, transmission and distribution network, a seven-level supply chain has been introduced and present-ed schematically. The aim of this paper is to optimize a case study using a fuzzy goal-programming multi-period model considering environmental and economic costs and revenue as fuzzy goals and maximize the total degree of satisfaction of goals as objective function. A small-sized problem was solved using GAMS 23.2.1 software and sensitivity analysis was conducted on its parameters. To the best of our knowledge, this is the first study that presents a fuzzy goal program-ming model for the optimization of sustainable natural gas supply chain by focus-ing on the environmental and economic costs and total revenue of gas products and the other main contribution of this research is focused to the developing of the mentioned model.