Minimizing Makespan in a Class of Reentrant Shops

An efficient simple metaheuristic for minimizing the makespan in two-machine no-wait job shops

Solving Re-entrant No-wait Flow Shop Scheduling Problem

In this study, we consider the production environment of no-wait reentrant flow shop with the objective of minimizing makespan of the jobs. In a reentrant flow shop, at least one job should visit at least one of the machines more than once. In a no-wait flowshop scheduling problem, when the process of a specific job begins on the first machine, it should constantly be processed without waiting ...

A Heuristic to Minimize Makespan in Proportional Parallel Flow Shops

This paper addresses the problem of minimizing the makespan on a two-stage parallel flow shops with proportional processing times. The problem of scheduling n independent jobs on m proportional parallel flow shops to minimize makespan is known to be NP-hard and hence too difficult to solve in polynomial time. A multiphase heuristic algorithm to minimize the makespan on two proportional parallel...

A Fluid Heuristic for Minimizing Makespan in Job Shops

We describe a simple online heuristic for scheduling job shops. We assume there is a fixed set of routes for the jobs, and many jobs, say N , on each route. The heuristic uses safety stocks and keeps the bottleneck machine busy at almost all times, while the other machines are paced by the bottleneck machine. We perform a probabilistic analysis of the heuristic, under some assumptions on the di...

On-line scheduling of small open shops

We investigate the problem of on-line scheduling open shops of two and three machines with an objective of minimizing the schedule makespan. We 1rst propose a 1.848-competitive permutation algorithm for the non-preemptive scheduling problem of two machines and show that no permutation algorithm can be better than 1.754-competitive. Secondly, we develop a (27=19)-competitive algorithm for the pr...