PLANET Technology Information Day Prague, May 26, 2003
16:10 - 17:00

Roman Barták (Charles University, Czech Republic)
Planning and Scheduling - Two Worlds in One System

Abstract

Planning and scheduling are notions used in different meanings by different communities which might be confusing. In the talk, we explain the difference between these notions: traditional planning deals with the problem of finding activities to satisfy a given goal while traditional scheduling solves the problem of allocating known activities to limited resources and to limited time. In many real-life problems both tasks should be accomplished together. Then the typical solving method is to separate planning and scheduling into two modules: the planning problem is solved first, i.e., the set of activities is generated, and the scheduling problem is solved next, i.e., the activities are allocated to resources and to time. In the talk we argue that such separation is not appropriate for some real-life problems and we give several examples where planning and scheduling should be performed together. Then we present a technology based on constraint satisfaction to resolve such integrated planning and scheduling problems. In particular, we show how to model complex resources with transition schemes and how to model dependencies between the resources. The presented technology is currently used by Visopt ShopFloor system for solving production scheduling problems in complex industries like chemical, pharmaceutical, or food industries.

Biography

Roman Barták got his Ph.D. in Computer Science at Charles University, Prague in 1997. Since then he works as an assistant professor and a researcher there. He leads the Constraint & Logic Programming Research Group that is involved in activities of the ERCIM Working Group on Constraints and PLANET II. Since 1999 he leads research activities of Visopt BV, a multinational company located in The Netherlands, Israel, Germany, and Czech Republic. He is the main architect of the scheduling engine being developed by this company. His work focuses on techniques of constraint satisfaction and their application to planning and scheduling. Dr. Barták is teaching a course on Constraint Programming at Charles University since 1998 and he had several tutorial-like invited talks over Europe. He is the author of the On-line Guide to Constraint Programming; he also published several journal surveys on Constraint Programming.