Ger Koole

Submitted papers:

Call center data analysis and model validation (with Siqiao Li and Sihan Ding).
Transfer-Learning Across Datasets with Different Input Dimensions: An Algorithm and Analysis for the Linear Regression Case (with Luis Silvestrin, Harry van Zanten, and Mark Hoogendoorn).
A framework for modelling booking time-dependent cancellations in airline revenue management (with Daniel Hopman and Rob van der Mei).
Practical limitations of revenue management: theory versus practice (with Daniel Hopman and Rob van der Mei).
The theory of revenue management: a review of demand forecasting, pricing and optimisation (with Daniel Hopman and Rob van der Mei).
Optimal contact center staffing and scheduling with machine learning (with Siqiao Li and Qingchen Wang).
Implementing rapid cancer diagnositics (with Anne van der Werf, Sonja Zweegman and others).
Waiting-time distributions in blended multi-server queues with impatient customers (with René Bekker, Petra Vis and Bartlomiej Zaber).

Refereed papers:

An investigation of the exposure effect of recommender systems in hospitality (with Rik van Leeuwen and Koen Hoogkamp). Decision Analysis Journal 10, 2024.
A practice-oriented overview of call center workforce planning (with Siqiao Li).
Stochastic Systems 13(4):479-495, 2023.
Anomaly detection in univariate time series incorporating active learning (with Rik van Leeuwen).
Journal of Computational Mathematics and Data Science 6, 2023.
Single-dimensional leg-level dynamic programming with booking-time dependent cancellation probabilities for revenue management (with Daniel Hopman and Rob van der Mei).
International Journal of Revenue Management 13(1/2):99-122, 2022.
Data-driven market segmentation in hospitality using unsupervised machine learning (with Rik van Leeuwen).
Machine Learning with Applications 10, 2022.
Demand forecasting in hospitality using smoothed demand curves (with Rik van Leeuwen).
Journal of Revenue and Pricing Management 21:487-502, 2022.
Modeling COVID-19 hospital admissions and occupancy in the Netherlands (with René Bekker and Michiel uit het Broek).
European Journal of Operational Research 304(1):207-218, 2023.
Optimal call center forecasting and staffing (with Sihan Ding).
Probability in the Engineering and Informational Sciences 36(2):254-263, 2022.
A machine learning approach to itinerary-level booking prediction in competitive airline markets (with Daniel Hopman and Rob van der Mei).
International Journal of Revenue Management 12(1):1, 2021.
Front-office multitasking between service encounters and back-office tasks (with Benjamin Legros, Oualid Jouini and Zeynep Aksin).
European Journal of Operational Research 287(3):946-963, 2020.
Should we wait before outsourcing? Analysis of a revenue-generating blended contact center (with Benjamin Legros and Oualid Jouini).
Manufacturing & Service Operations Management 23(5):1118-1138, 2020.
An adaptive priority policy for radiotherapy scheduling (with Siqiao Li and Xiaolan Xie).
Flexible Services and Manufacturing Journal 32:154-180, 2020.
A comparative study of state-of-the-art machine learning algorithms for predictive maintenance (with Luis Silvestrin and Mark Hoogendoorn).
2019 IEEE Symposium Series on Computational Intelligence, Xiamen (CN), pages 760-767.
Buffering locations in retail deliveries (with Dmitrii Erkin, Elenna Dugundji, Joaquim Gromicho and Rob van der Mei).
Procedia Computer Science 151:116-123, 2019.
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.
Single-leg revenue management with downsell and delayed decision-making (with Daniel Hopman and Rob van der Mei).
Journal of Revenue and Pricing Management 16(6): 594-606, 2017.
Flexible bed allocations for hospital wards (with René Bekker and Dennis Roubos).
Health Care Management Science 20(4):453-466, 2017.
A case for exploratory data analysis in revenue management forecasting: a case study of a small and independent hotel in The Netherlands (with Dirk Sierag, Jean-Pierre van der Rest, Rob van der Mei and Bert Zwart).
International Journal of Revenue Management 10:28-51, 2017.
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.
On the performance of small-scale living facilities in nursing homes: a simulation approach (with Dennis Moeke, Ruben van de Geer and René Bekker).
Operations Research for Health Care 11:20-34, 2016.
Optimal scheduling in call centers with a callback option (with Benjamin Legros and Oualid Jouini).
Performance Evaluation 95:1–40, 2016.
What are we waiting for? Factors influencing completion times in an academic and peripheral emergency department (with Irene Vegting and 10 others).
The Netherlands Journal of Medicine 73(7):331-340, 2015.
Task scheduling in long-term care facilities: A client-centered approach (with Alexander Lieder, Dennis Moeke and Raik Stolletz).
Operations Research for Health Care 6:11-17, 2015.
Simulation-based optimization of staffing levels in an emergency department (with Karim Ghanes and others).
Simulation 91(10):942-953, 2015.
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.
Revenue Management under Customer Choice Behaviour with Cancellations and Overbooking (with Dirk Sierag, Rob van der Mei, Jean-Pierre van der Rest and Bert Zwart).
European Journal of Operational Research 246(1):170-185, 2015.
Implementation of internet treatment for depression and anxiety in routine mental health care: Results from a naturalistic study (with Robin Kenter and others).
Internet Interventions 2(1):77-83, 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.
Scale and skill mix efficiencies in nursing home staffing: Inside the black box (with Dennis Moeke and Lineke Verkooijen).
Health Systems 3:18–28, 2014.
Performance indicators for call centers with impatience (with Oualid Jouini and Alex Roubos).
IIE Transactions 45(3):341-354, 2013.
Trend visualization on Twitter: What's hot and what's not? (with Sandjai Bhulai, Peter Kampstra, Lidewij Kooiman, Marijn Deurloo and Bert Kok).
Proceedings of Data Analytics, Barcelona, pages 43-48, IARIA, 2012.
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.
Optimal outpatient appointment scheduling with emergency arrivals and general service times (with Paulien Koeleman).
IIE Transactions on Healthcare Systems Engineering 2(1):14-30, 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.
Estimating unconstrained customer choice set demand: A case study on airline reservation data (with Alwin Haensel and Jeroen Erdman).
Journal of Choice Modelling 4(3):75-87, 2011.
A note on profit maximization and monotonicity for inbound call centers (with Auke Pot).
Operations Research 59(5):1304-1308, 2011.
Improving CT scan capabilities with a new trauma workflow concept: Simulation of hospital logistics using different CT scanner scenarios (with Korik Alons, Marcel Dijkgraaf, P.H.P. Fung Kon Jin, C. van Kuijk, L.F.M. Beenen, and Carel Goslings).
European Journal of Radiology 80(2):504-509, 2011.
Analyzing completion times in an academic Emergency Department: Coordination of care is the weakest link (with Annemieke van Dongen and 6 others).
The Netherlands Journal of Medicine 69(9):392-398, 2011.
Queues with waiting time dependent service (with René Bekker, Thomas Nielsen and Bo Nielsen).
Queueing Systems 68(1):61-78, 2011.
Estimating unconstrained demand rate functions using customer choice sets (with Alwin Haensel).
Journal of Revenue & Pricing Management 10(5):438-454, 2011.
Booking horizon forecasting with dynamic updating: A case study of hotel reservation data (with Alwin Haensel).
International Journal of Forecasting 27:942-960, 2011.
Dynamic control of a single-server system with abandonments (with Doug Down and Mark Lewis).
Queueing Systems 67(1):63-90, 2011.
Optimising a general repair kit problem with a service constraint (with Marco Bijvank and Iris Vis).
European Journal of Operational Research 204:76-85, 2010.
Dimensioning hospital wards using the Erlang loss model (with Arnoud de Bruin, René Bekker, and Lillian van Zanten).
Annals of Operations Research 178:23-43, 2010.
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.
Dynamic Load Balancing and Job Replication in a Global-Scale Grid Environment: a Comparison (with Menno Dobber and Rob van der Mei).
IEEE Transactions on Parallel and Distributed Systems 20:207-218, 2009.
Resource allocation in grid computing (with Rhonda Righter).
Journal of Scheduling 11:163-173, 2008.
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.
Modeling "Just-in-Time" communication in distributed real-time multimedia applications (with Ran Yang, Rob van der Mei, Dennis Roubos, Frank Seinstra, and Henri Bal).
Proceedings of CCGrid, Lyon, pages 518-525, IEEE Computer Society Press, 2008.
On the optimization of resource utilization in distributed multimedia applications (with Ran Yang, Rob van der Mei, Dennis Roubos, and Frank Seinstra).
Proceedings of CCGrid, Lyon, pages 358-365, IEEE Computer Society Press, 2008.
Optimal outpatient appointment scheduling (with Guido Kaandorp).
Health Care Management Science 10:217-229, 2007.
A Prediction Method for Job Runtimes on Shared Processors: Survey, Statistical Analysis and New Avenues (with Menno Dobber and Rob van der Mei).
Performance Evaluation 64:755-781, 2007.
Modeling the emergency cardiac in-patient flow: An application of queueing theory (with Arnoud de Bruin, Bert van Rossum, and Marieke Visser).
Health Care Management Science 10:125-137, 2007.
Monotonicity in Markov reward and decision chains: Theory and applications.
Foundations and Trends in Stochastic Systems 1:1-76, 2006.
Statistical properties of task running times in a global-scale grid environment (with Menno Dobber and Rob van der Mei).
Proceedings of CCGrid, Singapore, pages 150-153, IEEE Computer Society Press, 2006.
Approximating multi-skill blocking systems by hyperexponential decomposition (with Geert Jan Franx and Auke Pot).
Performance Evaluation 63:799-824, 2006.
Workload minimization in re-entrant lines (with Auke Pot).
European Journal of Operational Research 174:216-233, 2006.
The effect of service time variability on maximum queue lengths in MX/G/1 queues (with Misja Nuyens and Rhonda Righter).
Journal of Applied Probability 42:883-891, 2005.
Dynamic load balancing experiments in a grid (with Menno Dobber and Rob van der Mei).
Proceedings of CCGrid, Cardiff, pages 1063-1070, IEEE Computer Society Press, 2005.
Message delay in Mobile Ad Hoc Networks (with Robin Groenevelt and Philippe Nain).
Performance Evaluation 62:210-228, 2005.
Dynamic load balancing for a grid application (with Menno Dobber and Rob van der Mei).
In Proceedings of HiCP 2004, Bangalore, pages 342-352, Springer LNCS 3296, 2004.
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.
An explicit solution for the value function of a priority queue (with Philippe Nain).
Queueing Systems 47:251-282, 2004.
A formula for tail probabilities of Cox distributions.
Journal of Applied Probability 41:935-938, 2004.
Convexity in tandem queues.
Probability in the Engineering and Informational Sciences 18:13-31, 2004.
Telephone call centers: Tutorial, review, and research prospects (with Noah Gans and Avishai Mandelbaum).
Manufacturing and Service Operations Management 5:79-141, 2003.
On the structure of value functions for threshold policies in queueing models (with Sandjai Bhulai).
Journal of Applied Probability 40:613-622, 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.
On the bias vector of a two-class preemptive priority queue (with Robin Groenevelt and Philippe Nain).
Mathematical Methods of Operations Research 55:107-120, 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.
A stochastic batching and scheduling problem (with Rhonda Righter).
Probability in the Engineering and Informational Sciences 15:465-479, 2001.
Optimal transmission policies for noisy channels (with Zhen Liu and Rhonda Righter).
Operations Research 49:892-899, 2001.
On deviation matrices for birth-death processes (with Floske Spieksma).
Probability in the Engineering and Informational Sciences 15:239-258, 2001.
On the comparison of queueing systems with their fluid limits (with Eitan Altman and Tania Jiménez).
Probability in the Engineering and Informational Sciences 15:165-178, 2001.
On the value of learning for Bernoulli bandits with unknown parameters (with Sandjai Bhulai).
IEEE Transactions on Automatic Control 45:2135-2140, 2000.
On the convergence of the power series algorithm (with Gerard Hooghiemstra).
Performance Evaluation 42:21-39, 2000.
On the value function of a priority queue with an application to a controlled polling model (with Philippe Nain).
Queueing Systems 34:199-214, 2000.
Stochastic scheduling with event-based dynamic programming.
Mathematical Methods of Operations Research 51:249-261, 2000.
Minimizing response times and queue lengths in systems of parallel queues (with Panayotis Sparaggis and Don Towsley).
Journal of Applied Probability 36:1185-1193, 1999.
On the static assignment to parallel servers.
IEEE Transactions on Automatic Control 44:1588-1592, 1999.
A transformation method for stochastic control problems with partial observations.
Systems and Control Letters 35:301-308, 1998.
Structural results for the control of queueing systems using event-based dynamic programming.
Queueing Systems 30:323-339, 1998.
On submodular value functions and complex dynamic programming (with Eitan Altman).
Stochastic Models 14:1051-1072, 1998.
Optimal control of tandem reentrant queues (with Rhonda Righter).
Queueing Systems 28:337-347, 1998.
Stochastic bounds for queueing systems with multiple on-off sources (with Zhen Liu).
Probability in the Engineering and Informational Sciences 12:25-48, 1998.
Optimal control in light traffic Markov decision processes (with Olaf Passchier).
Mathematical Methods of Operations Research 45:63-79, 1997.
Assigning a single server to inhomogeneous queues with switching costs.
Theoretical Computer Science 182:203-216, 1997.
On the use of the power series algorithm for general Markov processes, with an application to a Petri net.
INFORMS Journal on Computing 9:51-56, 1997.
On suboptimal policies in multi-class tandem models (with Arie Hordijk).
Probability in the Engineering and Informational Sciences 10:29-39, 1996.
Scheduling a repairman in a finite source system (with Martin Vrijenhoek).
Mathematical Methods of Operations Research 44:333-344, 1996.
On the pathwise optimal Bernoulli routing policy for homogeneous parallel servers.
Mathematics of Operations Research 21:469-476, 1996.
A simple proof of the optimality of a threshold policy in a two-server queueing system.
Systems and Control Letters 26:301-303, 1995.
Optimal repairman assignment in two symmetric maintenance models.
European Journal of Operations Research 82:295-301, 1995.
Control of a random walk with noisy delayed information (with Eitan Altman).
Systems and Control Letters 24:207-213, 1995.
Analysis of a customer assignment model with no state information (with Arie Hordijk and Anneke Loeve).
Probability in the Engineering and Informational Sciences 8:419-429, 1994.
Stochastic scheduling games with Markov decision arrival processes (with Eitan Altman).
Computers and Mathematics with Applications 26(6):141-148, 1993.
Optimal server assignment in the case of service times with monotone failure rates.
Systems and Control Letters 20:233-238, 1993.
On the optimality of LEPT and μc rules for parallel processors and dependent arrival processes (with Arie Hordijk).
Advances in Applied Probability 25:979-996, 1993.
Marked point processes as limits of Markovian arrival streams (with Sören Asmussen).
Journal of Applied Probability 30:365-372, 1993.
On the assignment of customers to parallel queues (with Arie Hordijk).
Probability in the Engineering and Informational Sciences 6:495-511, 1992.
The μc-rule is not optimal in the second node of the tandem queue: a counterexample (with Arie Hordijk).
Advances in Applied Probability 24:234-237, 1992.
On the shortest queue policy for the tandem parallel queue (with Arie Hordijk).
Probability in the Engineering and Informational Sciences 6:63-79, 1992.
On the optimality of the generalized shortest queue policy (with Arie Hordijk).
Probability in the Engineering and Informational Sciences 4:477-487, 1990.

Other scientific papers:

The slow-server problem with multiple slow servers.
To appear in 100th anniversary volume of Queueing Systems 100:469-471, 2022.
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 comprehensive simulation modeling of an emergency department: a case study for simulation optimization of staffing levels (with Karim Ghanes and others). Proceedings of the 2014 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.
Appointment scheduling using optimization via simulation (with Paulien Koeleman).
Proceedings of the 2012 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.
An evaluation of a Shockroom located CT scanner: a Randomized study of Early Assessment by CT scanning in Trauma patients in the bi-located Trauma center North-West Netherlands (REACT trial) (with 13 others).
BMC Emergency Medicine 8(10), 2008.
Bottleneck analysis of emergency cardiac in-patient flow in a university setting: an application of queueing theory (with Arnoud de Bruin and Marieke Visser).
Clinical and Investigative Medicine 28(6): 316-317, 2005.
Approximate dynamic programming in multi-skill call centers (with Auke Pot).
Proceedings of the 2005 Winter Simulation Conference.
Routing to parallel homogeneous queues.
Presented at the Lorentz Center workshop in honor of Arie Hordijk, March 2005.
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.
Comparing queueing systems with heterogeneous on-off sources (with Zhen Liu and Don Towsley).
Technical Report WS-533, Vrije Universiteit Amsterdam, 1999.
Optimal admission, routing and service assignment control: the case of single buffer queues (with Eitan Altman, Bruno Gaujal, and Arie Hordijk).
In Proceedings of the 37th IEEE CDC, Tampa, pages 2119-2124, 1998.
The deviation matrix of the M/M/1 and M/M/1/N queue, with applications to controlled queueing models.
In Proceedings of the 37th IEEE CDC, Tampa, pages 56-59, 1998.
Nonconservative service for minimizing cell loss in ATM networks (with Zhen Liu).
In Proceedings of WATM '95, Paris, pages 123-130, 1995.
On scheduling and routing problems with a partially observed environment (with Olaf Passchier).
Technical Report TW-95-13, Leiden University, 1995.
Polling models with threshold switching (with Onno Boxma and Isi Mitrani).
In Quantative Methods in Parallel Systems, pages 129-140, Springer-Verlag (Esprit Basic Research Series), 1995.
Queueing-theoretic solution methods for models of parallel and distributed systems (with Onno Boxma and Zhen Liu).
In Performance Evaluation of Parallel and Distributed Systems - Solution Methods, CWI Tract 105 & 106, CWI, Amsterdam, 1994.
On the optimality of FCFS for networks of multi-server queues.
Technical Report BS-R9235, CWI, Amsterdam, 1992.
Assigning customers of multiple classes to parallel servers.
Technical Report TW-91-07, Leiden University, 1991.

Publications in the professional literature:

Posts at WFManagement blog.
2013.
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.
Kwantitatieve methoden voor zorglogistiek (with René Bekker).
Part 2 of Logistiek in de Zorg - P2 Capaciteit en Aanbod, LogiZ, pages 79-122, 2011.
Parkeeromzet verhogen met Revenue Management (with Maarten Soomer, Kevin Pak, and Rob van der Mei).
Parkeer Magazine 5(1):16-17, 2009.
Grootte van Zorgeenheden (with Arnoud de Bruin, Ben Nijman, Rien Caljouw, and Marieke Visser).
Zorgvisie 37(4):29, 2007.
Logistiek in de gezondheidszorg: Een bedrijfskundige benadering (with Jan Jurriens).
Technologie in de Gezondheidszorg 22(3):5-7, 2006.
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.

Popular-scientific articles:

Op tijd naar het toilet door data-gedreven capaciteitsplanning (with Dennis Moeke and René Bekker).
To appear in STAtOR.
Ehealth verhoogt efficiëntie en kwaliteit van gezondheidszorg.
Reformatorisch Dagblad 24 February 2011, pages 7-8.
De wiskunde van het wachten.
Pythagoras 43(1):30-32, 2003.
Met wiskunde naar de zon.
Pythagoras 42(5):12-15, 2003.
Eurodiffusie: een model voor je portemonnee.
STAtOR 3(4):13-15, 2002.
Het modelleren van de Eurodiffusie.
Nieuwe Wiskrant 21(4):24-26, 2002.
The Euro Diffusion Project (with Piet van Blokland, Lorna Booth, Kirankumar Hiremath, Michiel Hochstenbach, Sorin Pop, Marieke Quant, and Djoko Wirosoetisno).
Proceedings of the 42nd European Study Group with Industry, CWI syllabus 51, pages 41-57, 2002.
Stochastisch dynamisch programmeren.
Nieuwe Wiskrant 21(3):23-26, 2002.
Virtuele wetenschap.
STAtOR 2(3): 27-28, 2001.
Over wiskundig modelleren en call centers.
Nieuwe Wiskrant 20(3):8-12, 2001.
Wiskunde tussen model en werkelijkheid.
Public lecture, Vrije Universiteit Amsterdam, 30 November 2000.
An optimal dice rolling policy for Risk.
Nieuw Archief voor Wiskunde 12:49-52, 1994.

Interviews:

8 interviews in Succesformules (with Ton Langendorff and Kees Oosterlee).
Platform Wiskunde Nederland, Amsterdam, 2014.
Waarheid met kans nul (with Gerard Alberts and Jaap Molenaar).
Nieuw Archief voor Wiskunde (fifth series) 6:215-220, 2005.
Gele dingen die kunnen drijven (with Laurens Gelling and Jaap Molenaar).
Nieuw Archief voor Wiskunde (fifth series) 6:47-50, 2005.
Managementpotentieel (with Jaap Top and Roel Verstappen).
Nieuw Archief voor Wiskunde (fifth series) 5:232-236, 2004.
Tussen wetenschap en commercie (with Gerard Alberts and Hans Melissen).
Nieuw Archief voor Wiskunde (fifth series) 4:327-331, 2003.
Twee seconden is hier een eeuwigheid (with Gerard Alberts and Jaap Molenaar).
Nieuw Archief voor Wiskunde (fifth series) 4:224-228, 2003.
Het wiskunde B1,2-examen (with Alex van den Brandhof).
Nieuw Archief voor Wiskunde (fifth series) 4:165-166, 2003.
Behoud de keuzevrijheid - Wiskunde en politiek bij G. Zoutendijk (with Gerard Alberts).
Nieuw Archief voor Wiskunde (fifth series) 2:36-41, 2001.

Books:

An Introduction to Business Analytics.
MG books, Amsterdam, 2019.
Methoden en modellen voor zorglogistiek (with René Bekker).
MG books, Amsterdam, 2013.
Call center optimization.
MG books, Amsterdam, 2013.
Optimization of business processes.
Lecture notes.
Stochastic scheduling and dynamic programming.
PhD thesis, Leiden University, 1992.

Editorial work:

Special issue on call center management.
Management Science 54(2), 2008.
Special issue in honor of Arie Hordijk (with Lodewijk Kallenberg and Floske Spieksma).
Mathematical Methods of Operations Research 62(3), 2005.
Proceedings of the fifty-second European study group with industry (with Jan Bouwe van den Berg, Sandjai Bhulai, Joost Hulshof, Corrie Quant, JF Williams).
CWI Syllabus 55, CWI, Amsterdam, 2005.
Performance evaluation of parallel and distributed systems - solution methods (with Onno Boxma).
Proceedings of the 1993 Torino QMIPS workshop. CWI Tract 105 & 106, CWI, Amsterdam, 1994.

Press articles:

Podcast on CCmath.
weWFM, January 2023.
A crowbar to pry open healthcare and fight inefficiency.
ORTEC, 2022.
Interview over hedendaagse wetenschap.
DWIN, 2021.
Zwaarder geschut op planning nodig.
Telecommerce Magazine 06, 2011.
Sneldiagnose kanker: Hogere wiskunde in de zorg.
Synaps 76:14-15, December 2010.
Wiskunde toepassen.
Business Process Magazine 15(3):20-25, May 2009.
Pilot met diagnostische zorgpaden van start.
VUmc Tracer 10:7, 4 June 2009.
Een emmer vol slome eurocenten.
Volkskrant, 4 January 2003.