A network model for rotating workforce scheduling and related problems
Abstract
The rotating workforce scheduling problem, which is an important factor in improving worker productivity, involves the construction of an efficient sequence of work and recreation periods spanning over a number of weeks. This schedule must satisfy the workforce requirements during the various time periods and conform to all the other conditions imposed on the work/recreation periods and their sequence. We consider the modelling of the rotating workforce scheduling problem as a network flow problem. All the conditions enforced on the problem are incorporated in the network itself, except for the staff-covering constraints which are treated as side constraints. The optimal solution to the problem is a path in the network and is identified using a dual-based approach. The model deals with the three issues of recreation period identification, work/recreation period sequencing and shift scheduling simultaneously, and is designed to handle multiple shifts with time varying demands. A software package which includes the network model along with the solution technique is developed. To illustrate its use, the procedure, which is capable of solving large-scale problems, is applied to three well-known problems in rotating workforce scheduling. The computational results presented indicate that this procedure provides us with a useful method of solving large-scale complex problems in workforce scheduling. The general model developed can also be applied to other problems in sequencing and scheduling. To illustrate this feature, we consider a particular aspect of the examination timetabling problem where the objective is to assign blocks of examinations to time periods such that the number of students having back-to-back conflicts is minimized. The time periods are defined in such a way that the last period of any day and the first period of the following day are not considered to be back-to-back. The problem is modelled as a network flow problem where the solution to the problem is the shortest path in the network subject to side-constraints. A dual based approach followed by a K-shortest path enumeration technique is employed to identify this optimal path. The procedure is tested on a variety of test problems including a real problem faced by a large university.
Degree
Ph.D.
Advisors
Wong, Purdue University.
Subject Area
Management
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