- Optimal contact center staffing and scheduling with machine learning (with Siqiao Li and Qingchen Wang).
- Waiting-time distributions in call blending models (with René Bekker, Petra Vis and Bartlomiej Zaber).
- Cost-optimal call center forecasting and staffing (with Sihan Ding).
- Outsourcing and reservation; tools to manage blended sales and services operations in call centers (with Benjamin Legros and Oualid Jouini).
- Blended call center with idling times during the call service (with Benjamin Legros and Oualid Jouini).
IISE Transactions 50(4):279-297, 2018.
- A uniformization approach for the dynamic control of multi-server queueing systems with abandonments (with Benjamin Legros and Oualid Jouini).
Operations Research 66(1):200-209, 2018.
- Flexible staffing for call centers with non-stationary arrival rates (with Alex Roubos and Sandjai Bhulai).
In Markov Decision Processes in Practice (Richard Boucherie and Nico van Dijk, eds), Springer, 2017.
- Optimal scheduling in call centers with a callback option (with Benjamin Legros and Oualid Jouini).
Performance Evaluation 95:1–40, 2016.
- On the estimation of the true demand in call centers with redials and reconnects (with Sihan Ding and Rob van der Mei).
European Journal of Operational Research 246(1):250-262, 2015.
- Optimization of overflow policies in call centers (with Bo Nielsen and Thomas Nielsen).
Probability in the Engineering and Informational Sciences 29(3):461-471, 2015.
- Adaptive threshold policies for multi-channel call centers (with Benjamin Legros and Oualid Jouini).
IIE Transactions 47(4):414-430, 2015.
- Dynamic call center routing policies using call waiting and agent idle times (with Wyean Chan and Pierre L'Ecuyer).
Manufacturing & Service Operations Management 16(4):544–560, 2014.
- Performance indicators for call centers with impatience (with Oualid Jouini and Alex Roubos).
IIE Transactions 45(3):341-354, 2013.
- First in line waiting times as a tool for analyzing queueing systems (with Bo Nielsen and Thomas Nielsen).
Operations Research 60(5):1258-1266, 2012.
- Service level variability of inbound call centers (with Alex Roubos and Raik Stolletz).
Manufacturing & Service Operations Management 14(3):402-413, 2012.
- Staffing a call center with uncertain non-stationary arrival rate and flexibility (with Shuangqing Liao, Christian van Delft and Oualid Jouini).
OR Spectrum 34(3):691-721, 2012.
- A note on profit maximization and monotonicity for inbound call centers (with Auke Pot).
Operations Research 59(5):1304-1308, 2011.
- Queues with waiting time dependent service (with René Bekker, Thomas Nielsen and Bo Nielsen).
Queueing Systems 68(1):61-78, 2011.
- Online scheduling policies for multiclass call centers with impatient customers (with Oualid Jouini, Auke Pot, and Yves Dallery).
European Journal of Operational Research 207:258-268, 2010.
- A simple staffing method for multi-skill call centers (with Auke Pot and Sandjai Bhulai).
Manufacturing & Service Operations Management 10:421-428, 2008.
- Simple methods for shift scheduling in multi-skill call centers (with Sandjai Bhulai and Auke Pot).
Manufacturing & Service Operations Management 10:411-420, 2008.
- Approximating multi-skill blocking systems by hyperexponential decomposition (with Geert Jan Franx and Auke Pot).
Performance Evaluation 63:799-824, 2006.
- Scaling and comparison of fluid limits of queues applied to call centers with time-varying parameters (with Tania Jiménez).
OR Spectrum 26:413-422, 2004.
- A formula for tail probabilities of Cox distributions.
Journal of Applied Probability 41:935-938, 2004.
- Telephone call centers: Tutorial, review, and research prospects (with Noah Gans and Avishai Mandelbaum).
Manufacturing and Service Operations Management 5:79-141, 2003.
- Optimal shift scheduling with a global service level constraint (with Erik van der Sluis).
IIE Transactions 35:1049-1055, 2003.
- A queueing model for call blending in call centers (with Sandjai Bhulai).
IEEE Transactions on Automatic Control 48:1434-1438, 2003.
- Queueing models of call centers: An introduction (with Avishai Mandelbaum).
Annals of Operations Research 113:41-59, 2002.
- Managing uncertainty in call centres using Poisson mixtures (with Geurt Jongbloed).
Applied Stochastic Models in Business and Industry 17:307-318, 2001.
- On optimal call admission control in a resource-sharing system (with Eitan Altman and Tania Jiménez).
IEEE Transactions on Communications 49:1659-1668, 2001.
Other scientific papers:
- A simple solution for optimizing weekly agent scheduling in a multi-skill multi-channel contact center (with Siqiao Li and Oualid Jouini). Proceedings of the 2019 Winter Simulation Conference.
- A method for estimation of redial and reconnect probabilities in call centers (with Sihan Ding and Rob van der Mei). Proceedings of the 2013 Winter Simulation Conference.
- Call center capacity allocation with random workload (with Shuangqing Liao, Christian van Delft, Yves Dallery, and Oualid Jouini).
Proceedings of the 2009 International Conference on Computers & Industrial Engineering, July 6-8, Troyes, France.
- Approximate dynamic programming in multi-skill call centers (with Auke Pot).
Proceedings of the 2005 Winter Simulation Conference.
- Performance analysis and optimization in customer contact centers.
Proceedings of QEST 04, Enschede, pages 2-5, 2004.
- Routing heuristics for multi-skill call centers (with Auke Pot and Jérôme Talim).
Proceedings of the 2003 Winter Simulation Conference, New Orleans, pages 1813-1816, 2003.
- The mathematics of call centers.
``Research highlight'', Biennual report Stieltjes Institute, pages 31-35, 2000/2001.
- Exponential approximation of multi-skill call centers architecture (with Jérôme Talim).
In Proceedings of QNETs 2000, Ilkley (UK), pages 23/1-10, 2000.
Publications in the professional literature:
- Posts at WFManagement blog.
- Errors in Erlang97 Excel add-in module/Fouten in Erlang97 Excel add-in module (with Karin van Eeden and Edwin van der Hilst).
Telecommerce Nieuwsbrief week 4, 23 January 2013.
- WFM - Kosten, winst, SL en klanttevredenheid (with Annemiek van Moorst).
Call Center Magazine 11(6):14-16, 2005.
- WFM en de kwaliteit van data (with Annemiek van Moorst).
Call Center Magazine 11(4):14-16, 2005.
- Schaalvoordeel en skills bijten elkaar (with Annemiek van Moorst).
Call Center Magazine 11(2):14-15, 2005.
- WFM: goede voorspelling noodzakelijk maar niet voldoende (with Annemiek van Moorst).
Call Center Magazine 11(1):16-18, 2005.
- Over wiskundig modelleren en call centers.
Nieuwe Wiskrant 20(3):8-12, 2001.
- Call center optimization.
MG books, Amsterdam, 2013.
- Optimization of business processes.
- Special issue on call center management.
Management Science 54(2), 2008.
- Zwaarder geschut op planning nodig.
Telecommerce Magazine 06, 2011.