In this work we propose a simultaneous scheduling and control optimization formulation to address both optimal steady-state production and dynamic product transitions in continuous multiproduct tubular reactors. The simultaneous scheduling and control problem for continuous multiproduct tubular reactors is cast as a Mixed-Integer Dynamic Optimization (MIDO) problem. The dynamic behavior of the ...

The problem of scheduling under resource constraints is widely applicable. One prominent example is power management, in which we have a limited continuous supply of power but must schedule a number of power-consuming tasks. Such problems feature tightly coupled continuous resource constraints and continuous temporal constraints. We address such problems by introducing the Time Resource Network...

Although the Steel Mill Slab problem (prob 38 of CSPLib) has already been studied by the CP community, this approach is unfortunately not used anymore by steel producers since last century. Continuous casting is preferred instead, allowing higher throughput and better steel quality. This paper presents a CP model related to scheduling of operations for steel making with continuous casting. Acti...

The scheduling of mixed batch/continuous process plants is difficult since the model and solution have to deal with both discrete and continuous operations. Motivated by the need for the effective scheduling and control of operations in sugar milling, a new type of hybrid Petri nets called Hybrid Time Petri Nets(HTPN) is proposed, which allows the formulation of variable cycle time and variable...

An MILP model for the optimal scheduling of a lube oil and paraffin production plant is presented. The plant is composed of processing units that operate in continuous and discontinuous modes, and some are also duplicated. The raw materials for the process are stored in dedicated tanks, and the plant presents finite intermediate storage. The mathematical formulation was developed under a contin...

Abstract This work addresses the scheduling of continuous single-stage multiproduct plants with energy intensive processing tasks and time-dependent electricity cost and power supply. A new rolling horizon algorithm is proposed that consists of a planning model to predict the production levels and a continuous-time model for detailed scheduling. The results from a set of test problems from the ...

Department of Chemical Engineering, Princeton University Princeton, N.J. 08544 In this paper, a novel formulation is presented for the short-term scheduling of batch plants. The proposed formulation is based on a continuous time representation and results in a Mixed Integer Linear Programming (MILP) problem. In contrast to the previously published continuous-time scheduling formulations, the pr...

It is with the aim of solving scheduling problems with irregular cost functions that this paper focuses on the continuous assignment problem. It consists in partitioning a region of R into subregions of prescribed volumes so that the total cost is minimized. The dual problem of the continuous assignment problem is an unconstrained maximisation of a non-smooth concave function. The preemptive va...

Hierarchical reinforcement learning (RL) is a general framework which studies how to exploit the structure of actions and tasks to accelerate policy learning in large domains. Prior work in hierarchical RL, such as the MAXQ method, has been limited to the discrete-time discounted reward semiMarkov decision process (SMDP) model. This paper generalizes the MAXQ method to continuous-time discounte...

This paper presents a mathematical formulation for large-scale continuous process scheduling problem using unit-specific event-based continuous-time representation. The formulation is based on the work of Ierapetritou et al., (1999). The model considers the changeovers for multi-purpose units and tanks, setup constraints for parallel units and tanks, and includes product tanks that satisfy dema...