Benjamin Legros

41
Documents

Présentation

![](C:\Users\Benjamin\Documents\Mes documents\site web\pic moi.jpg)Professional Interests

Call Centers, Stochastic modeling, Optimization, Queues, Service operations management, Performance analysis, Financial Modeling.

Doctorate

Title: « Optimization of Multi-Skill and Multi-Channel Call Centers », defense on the 13th of December 2013 at Ecole Centrale Paris, Committee Members: Stephen E. CHICK, Zeynep AKSIN KARAESMEN, Raik STOLLETZ, Rob VAN DER MEI, Sébastien THOREL, Yves DALLERY, Ger KOOLE, and Oualid JOUINI.

Education

2003-2006: Engineering School - Ecole Centrale Paris

2005-2006: Research Master, MSROE – Ecole Centrale Paris, Ecole des Ponts

2001-2003: « Classe préparatoire aux grandes écoles » – Lycée Marcelin Berthelot

Consulting

2011-2014: Patent for the email routing in Multi-channel Call Centers- Interact-iv.com

2014-2015: Statistical analysis of call centers data (CWI, Interact-iv.com)

2012: Financial Modeling – ELIS

2006-2007: Project for the reopening of the train line Nantes-Châteaubriant (Train station Dimensioning). AREP (affiliated SNCF)

Teaching

Stochastic Models, 2009-2014, Ecole Centrale Paris, 2nd year students.

Financial Modeling, 2009-2014, ESG Management School, ESGF, EPF, EFREI, level M2

Statistics, 2009-2014, ESG Management School, ESGF, CFA ACE, EPF, EFREI, level L1-M2

Financial Mathematics, 2009-2014, ESG Management School, level L2

Risk Management, 2013-2014, ESG Management School, level M2

Academic Supervision

Academic research dissertation, 2010-2014, Ecole Centrale Paris

Final year dissertation, 2012-2014, ESG Management School

Administration

Competitive entrance examination at ESG Management School. Writing of the mathematical subject, Corrections, Oral examination, Meeting with academic inspectorate.

Languages

English fluent, French native

Software/Programming

Microsoft Office, Latex, Géoplan, GéoGébra, Photoshop, Arena, Matlab, Scilab, C++,VBA.

Scientific articles

Published

1. Legros, B., Jouini, O., & Dallery, Y. (2015). A flexible architecture for call centers with skill-based routing. International Journal of Production Economics, 159, 192-207.

2. Legros, B., Jouini O. and Koole G. (2015). Adaptive Threshold Policies for Multi-Channel Call Centers. IIE Transactions, 47:414-430.

Accepted

3. Legros, B., and Jouini, O. (2014). A Linear Algebraic Approach for the Computation of Sums of Erlang Random Variables. Ecole Centrale Paris. (Applied Mathematical Modelling).

Under Revision

4. Legros, B., Jouini, O., and Koole, G. (2014). Optimal Scheduling of Calls in Call Centers with a Callback Option. Ecole Centrale Paris. (Performance Evaluation).

5. Legros, B., Jouini, O., and Koole, G. (2014). A Uniformization Approach for the Dynamic Control of Multi-Server Queueing Systems with Abandonments. Ecole Centrale Paris. (Operations Research).

Submitted

6. Legros, B., Jouini, O., and Koole, G. (2013). Simultaneous treatment by imbrication. Ecole Centrale Paris (submitted to MSOM).

7. Legros, B., Jouini, O., and Koole, G. (2015). When should we reject? A priori versus a posteriori. Ecole Centrale Paris. (submitted to Queueing Systems).

8. Legros, B. and Jouini, O. (2014). Optimal Routing in the Two-Server Slow-Server Queue with Service Failure. Ecole Centrale Paris. (submitted to Queueing Systems).

9. Legros, B. and Jouini, O. (2014). Performance Analysis of a Queueing System with General Abandonments. Ecole Centrale Paris. (submitted to Operations Research Letters).

Working Paper

10. Routing commercials during the waiting time.

11. Control of the service admission in a contact center using the chat channel.

12. The switch to call option: speed in answer versus capacity of service.

Educational Books

1. Legros, B. (2011). Mini Manuel de Mathématiques pour la Gestion. DUNOD.

2. Legros, B. (2011). Mini Manuel de Mathématiques Financières. DUNOD.

3. A chapter in “Préparation au concours LINK (2012)”. Competitive examination of Mathematics. STUDYRAMA.

4. Legros, G. et Legros, B. (2015). Stratégie Financière des groupes. ELLIPSES.

Conference talks

1. Legros, B., Jouini, O., and Dallery, Y. (2011). Comparison of Flexible Architectures of Call Centers. 12éme congrès de la ROADEF, 02-04 mars 2012, Saint Etienne, France.

2. Legros, B., Jouini, O., and Dallery, Y. (2012). A New Flexible Architecture for Call Centers with Skill-Based Routing. 9th International Conference of Modeling, Optimization and Simulation, June 06-08, Bordeaux, France.

3. Legros, B., Jouini, O., and Koole, G. (2012). Managing operations in a multichannel call center. 4th meeting of the EURO Working Group on Stochastic Modeling, May 30- June 01, Paris, France.

4. Legros, B., Jouini, O., and Koole, G. (2013). Imbricating Tasks in a Multi-channel Contact Center. The International Conference on Modeling, Simulation and Applied Optimization (ICMSAO’13) April 28-30, 2013, Hammamet, Tunisia.

5. Legros, B., Jouini, O., and Koole, G. (2013). Adaptative Call Center Blending. 26th European Conference on Operational Research - XXVI EURO – INFORMS, 1-4 July, Rome, Italy.

6. Legros, B., Jouini, O., and Koole, G. (2013). Call Centers with a Call Back Option. 2nd International Workshop on Queueing Theory, December 15-19, Obergurgl, Austria.

7. Legros, B., Jouini, O., and Koole, G. (2014). Call centers with advertisements. 5th meeting of the EURO Working Group on Stochastic Modeling, June 29- July 02, Mannheim, Germany.

8. Legros, B., Jouini, O., and Koole, G. (2014). Optimal Routing in the Two-Server Slow-Server Queue with Service Failure. 20th Conference of the International Federation of Operational Research Societies, July 13- July 18, Barcelona, Spain.

9. Legros, B., Jouini, O., and Koole, G. (2014). Adaptative Call Center Blending. INFORMS annual meeting, November 9-12, San Francisco, United States.

10. Legros, B., Jouini, O., and Koole, G. (2014). Performance Analysis of a Queueing System with General Abandonments. 3rd International Workshop on Queueing Theory, December 15-19, Obergurgl, Austria.

11. Legros, B., Jouini, O., and Koole, G. (2015). Optimal tasks imbrication with the use of idling times. IIE Annual Conference, May 30- June 02, Nashville, United States.

12. Legros, B., Jouini, O., and Koole, G. (2015). When should we reject the call? A priori versus a posteriori rejection. 27th European Conference on Operational Research - XXVII EURO – INFORMS, 12-15 July, Glasgow, Scotland.

Publications

Publications

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Machine learning-based agent staffing under uncertainty: The case of a relay call center

Samer Alsamadi , Cléa Martinez , Canan Pehlivan , Nicolas Cellier , Oualid Jouini et al.

Expert Systems with Applications, 2025, 281, pp.127385. ⟨10.1016/j.eswa.2025.127385⟩

Article dans une revue hal-05025971v1

Machine learning-enhanced prediction of operating room occupation time and length of stay: a retrospective cohort study on emergency surgery care pathways

Anem Dupre , Oualid Jouini , Guillaume Lamé , Xiaolan Xie , Zied Jemai et al.

Journal of Clinical Monitoring and Computing, 2025, ⟨10.1007/s10877-025-01341-8⟩

Article dans une revue hal-05220926v1

Pooled testing in the presence of congestion

Saif Benjaafar , Oualid Jouini , Benjamin Legros , Bingnan Lu

Operations Research Letters, 2025, 58, pp.107208. ⟨10.1016/j.orl.2024.107208⟩

Article dans une revue hal-04869674v1
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How to optimize container withholding decisions for reuse in the hinterland?

Benjamin Legros , Jan Fransoo , Oualid Jouini

European Journal of Operational Research, 2024, 316 (3), pp.930-941. ⟨10.1016/j.ejor.2024.02.035⟩

Article dans une revue hal-04486824v1

A blockchain-based framework to optimize shipping container flows in the hinterland

Mariem Mhiri , Karim Al-Yafi , Benjamin Legros , Oualid Jouini , Mohamed Haouari

International Transactions in Operational Research, 2024, 31 (6), pp.3808-3841. ⟨10.1111/itor.13319⟩

Article dans une revue hal-04330902v1

Dynamic Policy for Idling Time Preservation

Benjamin Legros

Naval Research Logistics, 2023, 70 (1), pp.53-71. ⟨10.1002/nav.22086⟩

Article dans une revue hal-04877210v1

Appointment-driven queueing systems with non-punctual customers

Oualid Jouini , Saif Benjaafar , Bingnan Lu , Siqiao Li , Benjamin Legros

Queueing Systems, 2022, 101 (1), pp.1-56. ⟨10.1007/s11134-021-09724-9⟩

Article dans une revue hal-03605423v1
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The principal-agent problem for service rate event-dependency

Benjamin Legros

European Journal of Operational Research, 2022, 297 (3), pp.949-963. ⟨10.1016/j.ejor.2021.09.020⟩

Article dans une revue hal-03605421v1
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Transient analysis of an affine Queue-Hawkes process

Benjamin Legros

Operations Research Letters, 2021, 49 (3), pp.393-399. ⟨10.1016/j.orl.2021.04.001⟩

Article dans une revue hal-03605436v1

Appointment-driven Queueing Systems with Non-punctual Customers

Oualid Jouini , Saif Benjaafar , Bingnan Lu , Siqiao Li , Benjamin Legros

SSRN Electronic Journal, 2021, ⟨10.2139/ssrn.3876761⟩

Article dans une revue hal-05126535v1
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Routing analyses for call centers with human and automated services

Benjamin Legros

International Journal of Production Economics, 2021, 240, pp.108247. ⟨10.1016/j.ijpe.2021.108247⟩

Article dans une revue hal-03605426v1

Agents’ Self‐Routing for Blended Operations to Balance Inbound and Outbound Services

Benjamin Legros

Production and Operations Management, 2021, 30 (10), pp.3599-3614. ⟨10.1111/poms.13452⟩

Article dans une revue hal-03605428v1
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Age-based Markovian approximation of the G/M/1 queue

Benjamin Legros

Operations Research Letters, 2021, 49 (5), pp.708-714. ⟨10.1016/j.orl.2021.07.008⟩

Article dans une revue hal-03605431v1
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Performance Evaluation of Stochastic Systems with Dedicated Delivery Bays and General On-Street Parking

Abhishek Abhishek , Benjamin Legros , Jan Fransoo

Transportation Science, 2021, 55 (5), pp.1070-1087. ⟨10.1287/trsc.2021.1065⟩

Article dans une revue hal-03605434v1
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Front-office multitasking between service encounters and back-office tasks

Benjamin Legros , Oualid Jouini , O. Zeynep Akşin , Ger Koole

European Journal of Operational Research, 2020, 287 (3), pp.946-963. ⟨10.1016/j.ejor.2020.04.048⟩

Article dans une revue hal-02554304v1
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Late-rejection, a strategy to perform an overflow policy

Benjamin Legros

European Journal of Operational Research, 2020, 281 (1), pp.66 - 76. ⟨10.1016/j.ejor.2019.08.037⟩

Article dans une revue hal-03488761v1
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Should we wait before outsourcing? Analysis of a revenue-generating blended contact center

Benjamin Legros , Oualid Jouini , Ger Koole

Manufacturing and Service Operations Management, 2020, 23 (5), pp.1005-1331, C2. ⟨10.1287/msom.2019.0859⟩

Article dans une revue hal-02351773v1
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Analysis of base-stock perishable inventory systems with general lifetime and lead-time

Chaaben Kouki , Benjamin Legros , M. Zied Babai , Oualid Jouini

European Journal of Operational Research, 2020, 287 (3), pp.901-915. ⟨10.1016/j.ejor.2020.05.024⟩

Article dans une revue hal-02866472v1

A Time-Based Policy for Empty Container Management by Consignees

Benjamin Legros , Yann Bouchery , Jan C Fransoo

Production and Operations Management, 2019, pp.1503-1527. ⟨10.1111/poms.12996⟩

Article dans une revue hal-02019993v1
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On the scheduling of operations in a chat contact center

Benjamin Legros , Oualid Jouini

European Journal of Operational Research, 2019, 274 (1), pp.303-316. ⟨10.1016/j.ejor.2018.09.040⟩

Article dans une revue hal-01966254v1

Dynamic repositioning strategy in a bike-sharing system; how to prioritize and how to rebalance a bike station

Benjamin Legros

European Journal of Operational Research, 2019, 272 (2), pp.740-753. ⟨10.1016/j.ejor.2018.06.051⟩

Article dans une revue istex hal-02019994v1

A Uniformization Approach for the Dynamic Control of Queueing Systems with Abandonments

Benjamin Legros , Oualid Jouini , Ger Koole

Operations Research, 2018, 66 (1), pp.200 - 209. ⟨10.1287/opre.2017.1652⟩

Article dans une revue hal-01728724v1
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M/G/1 queue with event-dependent arrival rates

Benjamin Legros

Queueing Systems, 2018, 89 (3-4), pp.269-301. ⟨10.1007/s11134-017-9557-7⟩

Article dans une revue hal-01635318v1

Waiting time based routing policies to parallel queues with percentiles objectives

Benjamin Legros

Operations Research Letters, 2018, 46 (3), pp.356-361. ⟨10.1016/j.orl.2018.04.001⟩

Article dans une revue hal-02065918v1
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Blended call center with idling times during the call service

Benjamin Legros , Oualid Jouini , Ger Koole

IISE Transactions, 2018, 50 (4), pp.279 - 297. ⟨10.1080/24725854.2017.1387318⟩

Article dans une revue hal-01728725v1
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Call Centers with a Postponed Callback Offer

Benjamin Legros , Sihan Ding , Rob van Der Mei , Oualid Jouini

OR Spectrum, 2017, 39, pp.1097-1125. ⟨10.1007/s00291-017-0487-x⟩

Article dans une revue hal-01635315v1
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Reservation, a tool to reduce the balking effect and the probability of delay

Benjamin Legros

Operations Research Letters, 2017, 45 (6), pp.592 - 597. ⟨10.1016/j.orl.2017.09.003⟩

Article dans une revue hal-01635313v1
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Routing in a queueing system with two heterogeneous servers in speed and in quality of resolution

Benjamin Legros , Oualid Jouini

Stochastic Models, 2017, 33 (3), pp.392 - 410. ⟨10.1080/15326349.2017.1303615⟩

Article dans une revue hal-01728723v1
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Optimal scheduling in call centers with a callback option

Benjamin Legros , Oualid Jouini , Ger Koole

Performance Evaluation, 2016, 95, pp.1-40. ⟨10.1016/j.peva.2015.09.002⟩

Article dans une revue hal-01265244v1
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A linear algebraic approach for the computation of sums of Erlang random variables

Benjamin Legros , Oualid Jouini

Applied Mathematical Modelling, 2015, 39, pp.4971-4977. ⟨10.1016/j.apm.2015.04.013⟩

Article dans une revue hal-01265198v1
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Adaptive threshold policies for multi-channel call centers

Benjamin Legros , Oualid Jouini , Ger Koole

IIE Transactions, 2015, 47, pp.414-430. ⟨10.1080/0740817X.2014.928965⟩

Article dans une revue hal-01198404v1
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A flexible architecture for call centers with skill-based routing

Benjamin Legros , Oualid Jouini , Yves Dallery

International Journal of Production Economics, 2015, 159 (192-207), ⟨10.1016/j.ijpe.2014.09.025⟩

Article dans une revue hal-01265151v1

Why rational queueing of delay risk-sensitive users undermines the benefits of added resources

Benjamin Legros , Johan van Leeuwaarden

33rd European Conference on Operational Research (EURO 33rd), Jun 2024, Copenaghen, Denmark

Communication dans un congrès hal-05056257v1

Pigouvian taxation for socially responsible queueing in Naor's model

Benjamin Legros , Johan van Leeuwaarden

8th Stochastic Modelling Meeting, Jun 2024, Milan, Italy

Communication dans un congrès hal-05056237v1

Why rational queueing of loss-averse users undermines the benefits of added resources

Benjamin Legros , Johan van Leeuwaarden , Jan Fransoo

2023 INFORMS Annual Meeting: “Harnessing the data revolution … all with the power of OR/MS!”, Oct 2023, Phoenix, United States

Communication dans un congrès hal-04963242v1
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A New Flexible Architecture for Call Centers with Skill-Based Routing

Benjamin Legros , Oualid Jouini , Yves Dallery

9th International Conference on Modeling, Optimization & SIMulation, Jun 2012, Bordeaux, France

Communication dans un congrès hal-00728557v1