Scheduling is concerned with optimal allocation of limited resources to variegated tasks or activities over time.

Our research in this area covers exact as well as heuristic approaches.

Based on a solid research on classical scheduling theory, various features have been incorporated into classical models to account for complications arisen in practice. Our main interest is to efficiently generate schedules of guaranteed quality.

When the problems become too complex to be solved to optimality, heuristic and metaheuristics are used in practice. Our research focus here is on dealing with stochastic and dynamic problems, as they often occur in practice due to new jobs arriving continuously, stochastic processing time, or manufacturing tolerances. Dispatching rules are one popular way to deal with such dynamic and complex systems. Basically, whenever a machine finishes one operation, it uses a simple rule to decide which job to process next. Because it is challenging to design good dispatching rules, we use evolutionary algorithms to generate good rules automatically.

ORMS faculty

• Juergen Branke
• Bo Chen

Selected Publications

J. Branke and C. Pickardt. “Evolutionary search for difficult problem instances to support the design of job shop dispatching rules”. European Journal of Operational Research, to appear.

B. Chen, C. N. Potts, and G. J. Woeginger. A Review of Machine Scheduling: Complexity, Algorithms and Approximability. Handbook of Combinatorial Optimization (Vol. 3), 1998, Kluwer Academic Publishers. 21–169.

B. Chen, Y. Ye and J. Zhang. Lot-sizing scheduling with batch setup times. Journal of Scheduling 9(3) (2006), 299–310.

B. Chen and C.-Y. Lee. Logistics scheduling with batching and transportation. European Journal of Operational Research 189(3) (2008). 871–876.

B. Chen, E.G. Coffman, D. Dereniowski, and W. Kubiak, Normal-form preemption sequences for an open problem in scheduling theory. Journal of Scheduling (2015), 1–28.

C. Pickardt and J. Branke. “Setup oriented dispatching rules – a survey”. International Journal of Production Research, to appear.

C. Pickardt and J. Branke, T. Hildebrandt, J. Heger, and B. Scholz-Reiter. “Generating Dispatching Rules for Semiconductor Manufacturing to Minimize Weighted Tardiness”, Winter Simulation Conference, IEEE, 2010, 2504-2515.

S. Zhou, X. Zhang, B. Chen, and S. van de Velde. Tactical fixed job scheduling with spread-time constraints. Computers & Operations Research 47(2014), 53–60.