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

IX Simulation, Petri Nets, Genetic Algorithms
1. Kwan, Stephen K., Mark M. Davis and Allen G. Greenwood. A simulation model for determining
variable worker requirements in a service operation with time-dependent customer demand,
Queueing Systems, 3, 1988, 265–276.
Abstract. In a service operation where worker requirements have to be determined for short
scheduling time periods with nonstationary customer demand, the assumptions necessary for
applying steady-state solutions to elementary queueing models are usually violated. This paper
describes a simulation study of the behavior of such a service operation. The results are
compared with the steady-state solutions to a queueing model where individual scheduling time
periods are assumed to be independent. It is found that if the system utilization is below a
derived maximum value (based on a service level criterion), then the steady-state solutions are
robust enough to explain the behavior of the system and can be used to schedule worker requirements.
Keywords: Simulation, Service operations, Worker requirements, Queueing models
(Appears also in Section I.)
2. Liu, F.K. and D. Seagraves. An ISDN application-simulation modeling of NACD. Teletraffic
and Datatraffic in a Period of Change. ITC-13. Proceedings of the Thirteenth International
Teletraffic Congress. North-Holland, Amsterdam, The Netherlands, 1991, 279–284.
Abstract. Network automatic call distribution (NACD) utilizes the integrated services digital
network (ISDN) standard as a vehicle to effectively distribute calls between ACD sites. Due to
the dynamic nature of NACD, its routing algorithm, dependent upon the network congestion
status, is very hard to describe mathematically and its system performance is just as hard to
evaluate accurately. A simulation model, based on the SLAM II (simulation language for alternative
modeling) simulation language, is shown to be an effective tool to evaluate the system
performance of a network with the NACD application, due to its flexibility in implementing
routing criteria reflecting the unique NACD features. The result of simulation indicates that
use of NACD produces a significant improvement in grade of service and agent utilization. The
improvement is most pronounced when agent load is unbalanced in a non-NACD environment.
Keywords: Unbalanced agent load, Automatic call distribution, Integrated services digital network,
Routing algorithm, Network congestion status, SLAM II, Simulation language
3. Brigandi, Anthony J., Dennis R. Dargon, Michael J. Sheehan and Thomas Spencer III. AT&T’s
call processing simulator (CAPS) operational design for inbound call centers, Interfaces, 24 (1),
1994, 6–28.
Abstract. Since 1978, AT&T has been developing the call processing simulator (CAPS) to
design and evaluate inbound call centers. The current version of CAPS is a user-friendly PCbased
system employing a discrete event simulation model with animation and queuing models
of both the telecommunications network and AT&T’s business customer’s call center environment.
Using CAPS, AT&T can model a network of call centers utilizing advanced 800 network
188