Conceptual Models for Combined Planning and Scheduling

Planning and scheduling attracts an unceasing attention of computer science community. Several research areas like Artificial Intelligence, Operations Research and Constraint Programming joined their power to tackle the problems brought by real industrial life. Among them Constraint Programming plays the integrating role because it provides nice declarative capabilities for modelling and, at the same time, it can exploit directly the successful methods developed in AI and OR. In this paper we analyse the problems behind industrial planning and scheduling. In particular we give a survey of possible conceptual models for scheduling problems with some planning features. We compare their advantages and drawbacks and we explain the industrial background. These models were studied within the VisOpt project whose task is to develop a generic scheduling engine for complex production environments.