The general m-machine permutation flowshop problem with the total flow-time objective is known to be NP-hard for m ≥ 2. The only practical method for finding optimal solutions has been branch-and-bound algorithms. In this paper, we present an improved sequential algorithm which is based on a strict alternation of Generation and Exploration execution modes as well as Depth-First/Best-First hybri...

Population based metaheuristics, such as hybrid genetic algorithms or memetic algorithms, play an important role in the solution of combinatorial optimization problems. The memetic algorithm presented here for the no-wait flowshop scheduling problem addresses a hierarchically organized complete ternary tree to represent the population that putted together with a recombination plan resembles a p...

In this research, a permutation flowshop sequence-dependent group scheduling problem with minimization of total completion time i.e., is considered. Since the problem is shown to be strongly NP-hard, a hybrid genetic (HG) algorithm is proposed. The only available lower bounding (LB) method for the proposed research problem in the literature based on Branch and Price (B&P) algorithm is also enha...

This paper addresses the multistage hybrid flow shop (HFS) scheduling problems. The HFS is the special case of flowshop problem. Multiple parallel machines are considered in each stage in the HFS. The HFS scheduling problem is known to be strongly NPhard. Hence, many researchers proposed metaheuristic algorithms for solving the HFS scheduling problems. This paper develops a bat algorithm (BA) t...

The assembly flowshop scheduling problem has been studied recently due to its applicability in real life scheduling problems. It arises when various fabrication operations are performed concurrently in one stage. It was firstly introduced by Lee et al. (1993) in a flowshop environment. Later, Potts et al. (1995) considered the two-stage assembly flowshop problem with m concurrent operations in ...

A hybrid algorithm which combines particle swarm optimization (PSO) and iterated local search (ILS) is proposed for solving the hybrid flowshop scheduling (HFS) problem with preventive maintenance (PM) activities. In the proposed algorithm, different crossover operators and mutation operators are investigated. In addition, an efficient multiple insert mutation operator is developed for enhancin...

A flow line is a conventional manufacturing system where all jobs must be processed on all machines with the same operation sequence. Line buffers allow non-permutation flowshop scheduling (NPFS) and job sequences to be changed on different machines. A mixed-integer linear programming model for non-permutation flowshop scheduling and the buffer requirement along with manufacturing implication i...

Flowshop scheduling deals with processing a set of jobs through a set of machines, where all jobs have to pass among machines in the same order. With the exception of minimizing a makespan on two machines, almost all other flowshop problems in a general setup are known to be computationally intractable. In this paper we study a special case of flowshop defined by additional machine dominance co...

In this paper, we have studied a multiobjective hybrid flowshop scheduling problem where n independent jobs should be executed in a hybrid assembly line. The aim of our work is to optimize the makespan and the total tardiness of the whole production. A simulation based optimization algorithm is proposed here to solve this problem. It is a combination of the simulation software ARENA and the FLC...