Li Tieke

Hybrid variable neighborhood search for batch scheduling of hot rolled steel tube

Market demand of hot rolled seamless steel tube has the characteristics of multi-varieties and small batch. To meet the market demand and satisfy production requirements of seamless steel tube enterprises, this paper considers the machine maintenance factors and proposes a batch scheduling model. The model takes the machine adjustment and the idle time as optimization objective. To solve the problem, a hybrid variable neighborhood search combined with simulated annealing is designed. Experimental results show the feasibility and effectiveness of the model and algorithm.

Scheduling parallel multiple capacitated machines with sequence-dependent constraint

This paper introduces a new kind of parallel machines scheduling problem. Each job has a minimal processing time and all the machines are multiple capacitated machines in this problem. Each machine can process at most β jobs simultaneously according to the First-In-First-Out discipline, and the completion sequence and completion time interval between two jobs are restricted by the plan. A CSP model and a heuristic algorithm are put forward. The algorithm contains two stages, in the first stage, a method of job assignment based on expected starting time is presented; and in the second stage, the timetable is output to minimize the objective function. Computational tests reflect that both the model and the heuristic are feasible and efficient.