چکیده:
In this paper, for the first time in the literature, we integrated production scheduling decisions and WIPs planning decisions in a distributed environment. We study the distributed and flexible job shop scheduling problem (DFJSP) which involves the scheduling of jobs (products) in a distributed manufacturing environment, under the assumption that the shop floor of each factory/cell is configured as a flexible job shop. It is also assumed that the work-in-process (WIP) parts can be bought from the market instead of manufacturing them in-house, and they also can be sold in the market instead of processing their remaining operations and selling the end products. Moreover, the processing times of the operations can be decreased by paying a cost. However, there are a lower limit and an upper limit for the processing time of each operation. We formulate this general problem as a mixed integer linear programming (MILP) model. A fast heuristic algorithm is also developed to obtain good solutions in very short time. The algorithm is tested on some problem instances in order to evaluate its performance. Computational results show that the proposed heuristic is a computationally efficient and practical approach.
خلاصه ماشینی:
"com Modeling and solving the distributed and flexible job shop scheduling problem with WIPs supply planning and bounded processing times M.
According to the above two definitions for cijyf and c'ijyf, if the processing time of operation j of job i on machine y of FMU f is equal to Tijyf, ltijyf≤ Tijyf ≤ utijyf, then total processing cost of it is equal to Tijyf.
e. the overall completion time of all jobs on all FMUs. Obj: objective function value that is the total profit and equal to the sum of revenues of selling the WIPs minus the total costs including the fixed costs, the processing costs and the procurement costs; it is computed by the following equation: ijf ijf 1 2 3 Obj = (sp .
The paper investigated the distributed and flexible job shop scheduling problem (DFJSP) under the assumption that the WIPs can be bought from the market instead of manufacturing them in-house, and they also can be sold in the market instead of processing their remaining operations and selling the end products.
We proposed a MILP model to solve this general problem whose optimal solution simultaneously makes a plan for buying and selling the WIPs, makes a scheduling plan for all the FMUs, and determines the values of the processing times of the operations.
A genetic algorithm with tabu search procedure for flexible job shop scheduling with transportation constraints and bounded processing times."