this article addresses a multi-stage flowshop scheduling problem with equal number of unrelated parallel machines. the objective is to minimize the makespan for a given set of jobs in the system. this problem class is np-hard in the strong sense, so a hybrid heuristic method for sequencing and then allocating operations of jobs to machines is developed. a number of test problems are randomly ge...

In this paper, we propose different local search algorithms to solve a realistic variant of the flowshop problem. The variant considered here is a hybrid flexible flowshop problem with sequence-dependent setup times, and with the objective of minimizing the total tardiness. In this variant of flowshop, stage skipping might occur, i.e., not all stages must be visited by all jobs. This scheduling...

The hybrid or flexible flowshop problem is a generalization of the flowshop in such a way that every job can be processed by one among several machines on each machine stage. In recent years a number of effective exact methods have been developed. A major reason for this progress is the development of new job and machine based lower bounds as well as the rapidly increasing importance of constra...

This paper deals with a realistic variant of flowshop scheduling, namely the hybrid flexible flowshop. A hybrid flowshop mixes the characteristics of regular flowshops and parallel machine problems by considering stages with parallel machines instead of having one single machine per stage. We also investigate the flexible version where stage skipping might occur, i.e., not all stages must be vi...

We consider flowshop environments that consist of multiple stages and multiple machines in each stage. The flowshops are flexible in the sense that a task within a stage can be processed by any of the machines in the stage. We refer to this design as the hybrid flowshop. Our objective is to schedule a set of n jobs so as to minimize makespan. The problem is NP-complete even in the case of a sin...

This paper deals with a flowshop scheduling problem with a special blocking RCb (Release when Completing Blocking). In some industrial environments, such flexible production systems can be encountered. Genetic algorithms are good methods to solve these problems. A method is proposed to further improve solutions already found by genetic algorithms. It consists in marking out recurrent genes asso...

This research deals with a flexible flowshop scheduling problem with arrival and delivery of jobs in groups and processing them individually. Due to the special characteristics of each job, only a subset of machines in each stage is eligible to process that job. The objective function deals with minimization of sum of the completion time of groups on one hand and minimization of sum of the diff...

The flexible flowshop problem is a well known and common challenge. Extended with unrelated parallel machines and especially with the dynamic aspect of distributed release times, the problem gets very ‘close to reality’. Triggered by the growing complexity of logistic systems, the paradigm of central planning is being shifted to decentralised control. As part of this, an autonomous control conc...