nowadays one of the most important energy sources is natural gas. by depletion of oil reservoirs in the world, natural gasâ will emerge as the future energy source for human life. one of the major concerns of gas suppliers is being able to supply this source of energy the entire year. this concern intensifies during more consuming seasons of the year when the demand for natural gas increases, r...

While a great portion of the scheduling literature focuses on time-based criteria, the most important goal of management is maximizing the profitability of the firm. In this paper, the net preset value criterion is studied taking account of linear time-dependent cash flows in single machine and flow shop scheduling problems. First, a heuristic method is presented for the single machine scheduli...