Patent ID: 7062448
Filing Date: 2006-06-13
Classification: G06Q

Abstract:
1. A method of automated, computer-assisted plant occupancy planning in a process industry for sequencing of a discontinuous batch production and allocation of resources over time to a set of operations arising from batch planning that during execution use resources and require that productional restrictions be taken into account, and optimizing plant occupancy planning by modeling the plant occupancy planning as a resource-constrained project scheduling problem, taking into account the productional restrictions, each operation corresponding to an activity of the project having an execution mode, a start time and an completion time, and account restrictions on the availability of required resources and temporal constraints, the method comprising: executing software in a first stage to form a relaxation which simplifies the resource-constrained project scheduling problem, disregarding the restrictions on the availability of required resources, and taking into account the productional restrictions, the productional restrictions comprising minimum and maximum time lags between operations and a production break type which are independent of resources operations selection; executing software in a second stage to solve a temporal scheduling problem as a calendarization problem in networks using an iterative process; executing software in a third stage to investigate a solution to the temporal scheduling problem for its feasibility with respect to a non-relaxed problem of plant occupancy planning wherein if it is found that restrictions on availability of resources are violated in solving the temporal scheduling problem, violations are solved by introducing precedence relationships, and if it is found that not all resources have been selected for carrying out an operation, the unselected resources are selected; wherein the second stage of temporal scheduling and the third stage of introducing precedence relationships and selecting resources continue until a feasible plant occupancy plan has been determined or until the constraints to be taken into account in the second stage of temporal scheduling are contradictory, if a possibility investigated does not violate any productional restrictions, the plant occupancy plan is stored as a feasible solution and; wherein an investigation of possibilities according to the third stage that has not yet been reviewed is continued and a best solution with regard to a selectable objective function that does not decrease in the completion times of the operations is determined from the feasible solutions determined in the second stage.