《2016 A decomposition approach for the scheduling of a steel plant production》.pdfVIP

Computers and Chemical Engineering 25 (2001) 1647–1660 /locate/compchemeng A decomposition approach for the scheduling of a steel plant production Iiro Harjunkoski, Ignacio E. Grossmann * Department of Chemical Engineering, Carnegie Mellon Uniersity, Pittsburgh, PA 15213, USA Received 21 February 2001; received in revised form 25 July 2001; accepted 25 July 2001 Abstract In this paper we present a decomposition strategy for solving large scheduling problems using mathematical programming methods. Instead of formulating one huge and unsolvable MILP problem, we propose a decomposition scheme that generates smaller programs that can often be solved to global optimality. The original problem is split into subproblems in a natural way using the special features of steel making and avoiding the need for expressing the highly complex rules as explicit constraints. We present a small illustrative example problem, and several real-world problems to demonstrate the capabilities of the proposed strategy, and the fact that the solutions typically lie within 1–3% of the global optimum. © 2001 Published by Elsevier Science Ltd. Keywords: Mixed Integer Programming; Steel making; Scheduling; Heuristics; Disaggregation Nomenclature Indices G index of group I index of products L index of slot M index of machines Sets G set of groups I set of products L set of slots M set of machines MEAF