Multisite and multishift personnel planning with set-up costs

Abstract

Abstract Consideration is given to a personnel planning problem occurring in multisite projects. In this problem a set of facilities (different sites) need to complete a given work load over a planning horizon of several days. The workforce is skilled and can work on any facility and it is employed to work on a basis of workday shifts. A fixed set-up cost associated with each facility is incurred each time a facility starts operating. The problem seeks to determine when each facility should be operated as well as the manpower needed at each shift to complete the workload targets of all the facilities within the planning horizon at a minimum cost. First, a formulation of the new problem as a mixed-integer linear programme is given. Then, since the problem is shown to be NP-hard, a novel genetic algorithm (GA) is presented for its solution which incorporates a problem-specific coding together with new special merging rules for creating offspring that exploits the structure of the problem. Using results from the standard CPLEX optimizer we test the performance of the GA for a variety of operating environments. The results demonstrate very satisfactory performance for the GA in terms of both solution time and quality.