Scheduling internal audit activities: a stochastic combinatorial optimization problem

The problem of finding the optimal timing of audit activities within an organisation has been addressed by many researchers. We propose a stochastic programming formulation with Mixed Integer Linear Programming (MILP) and Constraint Programming (CP) certainty-equivalent models. In experiments neither approach dominates the other. However, the CP approach is orders of magnitude faster for large audit times, and almost as fast as the MILP approach for small audit times. Roberto Rossi is supported by Science Foundation Ireland under Grant No. 03/CE3/I405 as part of the Centre for Telecommunications Value-Chain-Driven Research (CTVR) and Grant No. 05/IN/I886. S. Armagan Tarim and Brahim Hnich are supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Grant No. SOBAG-108K027. R. Rossi ( ) · S. Prestwich Cork Constraint Computation Centre, University College, 14 Washington St. West, Cork, Ireland e-mail: [email protected] S. Prestwich e-mail: [email protected] R. Rossi Centre for Telecommunication Value-Chain Driven Research, University College, Dublin, Ireland e-mail: [email protected] S.A. Tarim · S. Karacaer Department of Management, Hacettepe University, Ankara, Turkey S.A. Tarim e-mail: [email protected] S. Karacaer e-mail: [email protected] B. Hnich Faculty of Computer Science, Izmir University of Economics, Izmir, Turkey e-mail: [email protected] 326 J Comb Optim (2010) 19: 325–346 This work generalises a previous approach by relaxing the assumption of instantaneous audits, and by prohibiting concurrent auditing.