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This paper presents a heuristic algorithm to solve flow shop scheduling problems (FSSP) with the criterion to minimise the system utilisation time with minimum of maximum completion time (makespan)...

The aim of this paper is to introduce the concept of arbitrary lags in n-jobs, m machines flowshop scheduling problem involving the processing times and transportation times of jobs. Start lag is the minimum time which must elapse between starting of job i on the first machine and starting of job i on the last machine. The stop lag for the job i is the minimum time which must elapse between completing job i on the first machine and completing it on the last machine. The concept of fuzzy processing time to represent the uncertainty, vagueness in processing of jobs is introduced. An algorithm to find the optimal sequence so as to minimise the total elapsed time subject to some specified lag time constraint is discussed. A numerical illustration is given to demonstrate the computational efficiency of proposed algorithm as a valuable analytical tool for the researchers.

Flow shop scheduling with sequence-dependent setup time is the most complicated case of scheduling of jobs. The operational cost of machines is related to the setup time required for processing of jobs on different machines. To express the randomness probabilities are associated with processing times of different attributes on given machines. The objective is to schedule n-jobs on m-machines to minimise operational cost of machines subject to minimum total elapsed time of jobs in a flow shop whenever the setup times on machines are sequence-dependent. As the problem is NP-hard, a heuristic algorithm is proposed to find the latest time so as to reduce operating time and hence the operational cost with minimum makespan. A numerical example is also given to substantiate the algorithm.

In today’s information age society, where activities are highly interdependent and intertwined, sharing of resources and hence waiting in queues is a common phenomenon that occurs in every facet of our lives. Flowshop scheduling with an objective of minimising the makespan is also an important task in manufacturing system. The present paper is an attempt to establish a linkage network of queues consisting of a biserial server and two parallel servers linked to a common server in series with a multistage flow shop scheduling system. The arrival and service pattern follow Poisson law. The completion time of jobs/customers in queue network (phase I of the service) will be the setup time for first machine in flowshop system having ‘m’ machines in series (phase II of the service). A heuristic approach to find optimal or near optimal sequence of jobs processing minimising the total elapsed time with minimum waiting time has been discussed for the queuing-scheduling linkage model. The performance of the algorithm is evaluated by a numerical illustration.