In this paper, two tools to improve the performance of the NEHbased heuristics for the flow shop problem with and without buffer constraints are proposed. The first tool is the use of the reversibility property of the problems considered and the second one is a new tie-breaking strategy to be use in the insertion phase of the NEH heuristic. In addition, we have analyzed the behavior of five ini...

A new hybrid flow shop scheduling problem with blocking is studied. The problem is characterized by multistage unrelated parallel machines and no intermediate buffer. Firstly, the math model of the hybrid scheduling problem is constructed. And then the computation method of production period is given. Due to there is no intermediate buffer, and there are unrelated parallel machines in multi-sta...

scheduling is an important subject of production and operations management area. in flow-shop scheduling, the objective is to obtain a sequence of jobs which when processed in a fixed order of machines, will optimize some well defined criteria. the concept of transportation time is very important in scheduling. transportation can be done by robots. in situations that robots are used to transpor...

This paper deals with the blocking flow shop problem and proposes an Iterated Local Search (ILS) procedure combined with a variable neighbourhood search (VNS) for the total tardiness minimization. The proposed ILS makes use of a NEH-based procedure to generate the initial solution, uses a local search to intensify the exploration which combines the insertion and swap neighbourhood and uses a pe...

In this paper we consider a job shop scheduling problem with blocking (zero buffer) constraints. Blocking constraints model the absence of buffers, whereas in the traditional job shop scheduling model buffers have infinite capacity. There are two known variants of this problem, namely the blocking job shop scheduling (BJSS) with swap allowed and the BJSS with no-swap. A swap is needed when ther...

In this paper the flow shop scheduling problem with minimizing two criteria simultaneously is consider. Selected criteria are: makespan and the sum of tardiness of jobs. For each separate criteria the problem is strongly NP-hard, which makes it NP-hard as well. There is a number of heuristic algorithms to solve the flow shop problem with various single objectives, but heuristics for multi-crite...

In a proportionate flow shop problem several jobs have to be processed through a fixed sequence of machines and the processing time of each job is equal on all machines. By identifying jobs with agents whose costs linearly depend on the completion time of their jobs and assuming an initial processing order on the jobs, we face two problems: the first is how to obtain an optimal order that minim...

This research combines between two different manufacturing concepts. On the one hand, flow shop scheduling is a well-known problem in production systems. The problem appears when a group of jobs shares the same processing sequence on two or more machines sequentially. Flow shop scheduling tries to find the appropriate solution to optimize the sequence order of this group of jobs over the existi...

A discrete event simulation model was developed to study the flow of material and product in a shop floor. It uses real time data available from a job shop sole dedicated to noncommercial contracts and as such deals with very seasonal demand. The objective of this model is to provide the shop with a decision support tool that will assist in evaluating the movement of products throughout the sho...