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

impatient hang up, and with limitations on the number of access circuits and waiting time. A
special iteration algorithm is applied to this model. As the comparison with simulation results
shows, this approach allows one to obtain good results.
Keywords: Automated call distribution system, Analytical model, ACD, Busy signal, Access
circuits, Waiting time, Iteration algorithm, Simulation results
28. Milito, Rodolfo A., Yonatan Levy and Yair Arian. Dynamic algorithms for distributed queues
with abandonments. Teletraffic and Datatraffic in a Period of Change. ITC-13. Proceedings of
the Thirteenth International Teletraffic Congress. North-Holland, Amsterdam, The Netherlands,
1991, 329–334.
Abstract. In this paper we consider the problem of distributing traffic to multiple parallel
queues based on incomplete and possibly inaccurate state information. This problem arises in
the context of intelligent networks where large customers rely on the network for traffic distribution
to multiple locations. The main contributions of the paper are: (i) classification of
approaches to the problem; (ii) a revenue-driven, Markovian decision model which captures
the crucial elements of the problem; profit maximization, multiple job classes, blocking, and
abandonments; and (iii) demonstration of the superior performance of implementable dynamic
policies.
29. Nowikow, P. and K. Wajda. Agent scheduling for ACD switches. Telecommunication Services
for Developing Economies. Proceedings of the ITC Specialist Seminar, Elsevier, Amsterdam,
The Netherlands, 1991, 655–660.
Abstract. The authors describe a system for staff scheduling in automatic call distribution
PBX exchanges based on gathered statistical data. General traffic engineering aspects for ACD
exchanges employing the Erlang C formula are presented. An algorithm for choosing the number
of active operators implementing an idea of ‘daily call profile’ is also included. Trials carried out
for a ROLM 9000 ACD exchange proved that system is technologically feasible and economically
attractive.
Keywords: ACD switches, Staff scheduling, Automatic call distribution PBX exchanges, Traffic
engineering aspects, ACD exchanges, Erlang-C formula, Daily call profile, ROLM-9000 ACD
exchange
30. Quinn, P., B. Andrews and H. Parsons. Allocating telecommunications resources at L.L. Bean,
Inc., Interfaces, 21, 1991, 75–91.
Abstract. We developed and implemented a model for optimizing the deployment of telemarketing
resources at L.L. Bean, a large telemarketer and mail-order catalog house. The
deployment levels obtained with economic optimization were significantly different from those
formerly determined by service-level criteria, and the resultant cost savings were estimated as
$9 to $10 million per year. To develop the economic-optimization approach, we used queueing
theory, devised an expected total-cost objective function, and accounted for retrial behavior and
potential caller abandonments through a regression model that related the abandonment rates
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