C Rajendran

In this work we address the problem of transforming a jobshop layout into a flowshop layout with the objective of minimizing the length of the resulting flowline. This problem is a special case of the well-known classical Shortest Common Supersequence (SCS) stringology problem. In view of the problem being NP-hard, an ant-colony algorithm, called PACO-SFR, is proposed. A new scheme of forming an initial supersequence of machines (i.e., flowline) is derived from a permutation of jobs, followed by the reduction in the length of the flowline by using a concatenation of forward reduction and inverse reduction techniques, machine elimination technique and finally an adjacent pair-wise interchange of machines in the flowline. The proposed ant-colony algorithm's performance is relatively evaluated against the best known results from the existing methods by considering many benchmark jobshop scheduling problem instances. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.