CALL CENTERS (CENTRES) - Faculty of Industrial Engineering and ...

Abstract. This paper details a new simulation and optimisation based system for personnel
scheduling (rostering) of Customs staff at the Auckland International Airport, New Zealand.
An integrated approach using simulation, heuristic descent and integer programming techniques
has been developed to determine near-optimal staffing levels. The system begins by using a new
simulation system embedded within a heuristic search to determine minimum staffing levels for
arrival and departure work areas. These staffing requirements are then used as the input to an
integer programming model which optimally allocates full and part-time staff to each period of
the working day. These shifts are then assigned to daily work schedules having a six-day-on,
three-day-off structure. The application of these techniques has resulted in significantly lower
staffing levels, while at the same time creating both high quality rosters and ensuring that all
passenger processing targets are met. This paper charts the development of this system, outlines
failures.
Keywords: Simulation, Heuristic, Optimisation, Staff scheduling, Personnel scheduling, Rostering,
Customs staff, Auckland International Airport, New Zealand, Heuristic descent, Integer
programming, Near optimal staffing levels, Minimum staffing levels, Integer programming model,
Full-time staff, Part-time staff
(Appears also in Section IX.)
64. Servi, L.D. and S. Humair. Optimizing Bernoulli routing policies for balancing loads on call centers
and minimizing transmission costs. Proceedings of the 37th IEEE Conference on Decision
and Control, IEEE, Piscataway, NJ, USA, 1998, 1653–1655.
Abstract. We address the problem of assigning probabilities at discrete time instants for routing
toll-free calls to a given set of call centers in order to minimize a weighted sum of transmission
costs and load variability at the call centers during the next time interval. We model the problem
as a tripartite graph and decompose finding the optimal probability assignment in the graph
into an estimation problem and a convex quadratic program problem. Using a heuristic that
uses gradient information around a given probability assignment we further address a practical
variant in which the number of probability assignments that can be changed at each time instant
is constrained.
Keywords: Bernoulli routing policy optimization, Call center load balancing, Transmission cost
minimization, Toll-free call routing, Load variability, Tripartite graph, Optimal probability assignment
decomposition, Estimation problem, Convex quadratic program problem, Heuristic,
Gradient information
65. Van Dijk, N.M. On hybrid combination of queueing and simulation. Simulation: Past, Present
and Future. 12th European Simulation Multiconference 1998. ESM’98. As Part of the 50th
Anniversary Celebrations of the University of Manchester - the Home of Computing. SCS, San
Diego, CA, USA, 1998, 731–735.
Abstract. This paper illustrates how simulation and queueing theory can and should go hand in
hand for a variety of practical problems, both in daily-life and industry, which are still open for
fundamental research. To this end, it highlights real-life cases taken from: daily-life situations
(postal office or bank); administrative logistics (reengineering); tele-servicing (call-centres); and
transportation (railways).
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