CHAPTER 6: OPERATIONS RESEARCH & MANAGEMENT

Transcription

1 CHAPTER 6: OPERATIONS RESEARCH & MANAGEMENT Programme director: Prof. dr N.M. van Dijk Department: METIS-code: uva/fee/res/or/prog JEL-classification: C4 VSNU-scores : Quality: 3, Productivity: 2, Relevance: 3, Viabitliy: 2 Starting date programme: 1989 Website: MEMBERS OF THE RESEARCH GROUP AND RESEARCH IN FTES Name Title Function Total 2005 Total 2006 Total 2007 Total 2008 Dept. Funding Adan, I.J.B.F. prof dr hgl KE 1 Al-Ibrahim, A. drs phd 0,45 0,45 0,45 - KE 1 Al-Ibrahim, A. drs phd 0,15 0,15 0,15 0,33 KE 3 Dijk, N.M. van prof dr hgl 0,50 0,50 0,50 0,50 KE 1 Duin, C.W. dr ud 0,40 0,46 0,46 0,46 KE 1 Haijema, R. drs phd 0,48 0,48 0,32 - KE 1 Hontelez, J.A.M. ir ud 0,00 0, KE 1 Joustra, P. drs phd - 0,07 0,30 0,30 AMC 1 Nunez Queija, R. dr uhd ,08 KE 1 Sluis, H.J. van der dr ud 0,50 0,50 0,50 0,50 KE 1 Volgenant, A. dr uhd 0,39 0,39 0,39 0,39 KE 1 Wal, J. van der prof dr hgl 0,25 0,25 0,25 0,25 KE 1 Total 1st flow of funds 2,97 3,10 3,17 2,48 Total 2nd flow of funds 0,00 0,00 0,00 0,00 Total 3rd flow of funds 0,15 0,15 0,15 0,33 Total 1st f.o.f. excl. Ph.D.'s 2,04 2,10 2,10 2,18 Total 1st-3rd flow of funds 3,12 3,25 3,32 2,81 Ph.D. students 1,08 1,15 1,22 0, PROGRAMME DESIGN The general research mission of the Programme can be formulated as threefold (i) The development and continuation of fundamental theoretical research in the areas of deterministic and stochastic operations research. (ii) The application and development of scientific research in these fields for technological and infrastructure applications. (iii) The dissemination of general insights and scientific results from the field of Operations Research for daily-life non-technical logistical situations. Accordingly, three lines of research and associated activities are distinguished: I Fundamental Theoretical Research In this category in turn three directions of research are followed: 1.1 Combinatorial Optimisation specialised to: Generalisations of the Travelling Salesman Problems such as Peripatetic Salesman Problem; Steiner Tree Problems on Graphs and Generalisations as multiweighted problems; 43

2 Degree constrained trees and problems with criteria as bottleneck, minimum deviation, and partial sum; Linear Assignment Problems This research is focused on both exact and heuristic methods. The heuristic methods are of most interest from a practical point of view, as in many cases a nearly optimal solution is also sufficient. Special interest has been developed for the numerical implementation of algorithms. 1.2 Queuing Network Analysis Stochastic service networks naturally arise in manufacturing (production lines), computer science (computer networks), telecommunications (long distance, satellite and mobile communications) and transportation (railway systems, traffic lights). The research themes are: the development of closed form (exact) expressions for stochastic service networks, most notably product form expressions for queuing networks; the development of simple insights in when and when not a stochastic network has this socalled product form steady state distribution. simple performance bounds for networks that are non-solvable due to practical phenomena such as finite capacity constraints, job-priorities or breakdowns. 1.3 Markov Chain Analysis Error Bound Analysis for Approximate Markov Chain Modelling As practical systems that arise in manufacturing, telecommunications and computer networking are often non-solvable for the reasons mentioned, based on the insights and results above, approximations and bounds have to be developed. The error introduced by such approximations or bounds is of practical interest. To this end a technique has been developed to provide analytical error bounds. The application and extension of this technique remains a continuing research interest for a variety of situations. Particular research problems are: error bounds for non-exponential stochastic networks; error bounds for the truncation of Markov chains; error bounds for sensitivity analysis Continuous time and large Markov Chain Modelling Continuous time Markov Chain Models are known to provide a powerful tool for the description and modelling for a variety of applied fields. Unfortunately, for computational purposes these systems are generally hard if not impossible to handle, as the state spaces are usually far too large. Different methods to overcome this intractability are of ongoing research, such as by aggregation methods and uniformization. II Fundamental Applied Research This concerns queuing network and Markov chain modelling for a number of applied technical fields in order to obtain computationally attractive results. Most notably: Telecommunications (mobile communications, long-distance communications) Transportation Networks (Public transportation, Railways) Inventory systems and Reliability Networks III Practical Research for Daily-life Logistics (Operations Management) This concerns the application of insights and techniques from Operations Research for a number of practical logistical environments such as in: Administrative and Production Logistics Health care and hospitals Call Centers 44

3 6.3 PROGRAMME EVALUATION Operations Research Van Dijk First of all, in response to the last research visitation, the programme sets itself the objectives of: A strong interaction among the group. A strong research orientation of all members. A more balanced and structured production over all members. The steps in these directions as already set and visible in earlier years have been continued and also been reflected in 2008, as by: An overall research mind setting and participation among the group Different research interactions among various members Productivity by each of the individual members All three categories of research of the programme design are represented by: Fundamental theoretical research: Duin / Duin and Van der Sluis / Van Dijk / Volgenant / Van der Wal Fundamental Applied Research Van der Sluis /Van der Wal/ Van Dijk and Van der Sluis/ Practical Research Van Dijk and Van der Sluis / Haijema, Van der Wal and Van Dijk / Hontelez / Joustra / Kortbeek, Haijema, Van der Wal and Van Dijk Over 2008 the research outcome in terms of paper acceptances for quality journals can be regarded as quite succesfull. The publication of some of these however is delayed until (see forthcoming). Some noteworthy publications are: Dijk, N.M. van & Sluis, E. van der (2008). To Pool or not to Pool in Call Centers. Production and Operations Management, 17, [A-ovb-brief volgt] Dijk, N.M. van & Sluis, E. van der (2008). Practical Optimization by OR and Simulation. Simulation Modelling Practice and Theory, 16, [B] Dijk, N.M. van, Haijema, R., Wal, J,. van der, Smit Sibinga, C. (2009). Blood Platelet Production: A novel approach for practical optimization. Forthcoming in Transfusion. The first has appeared in a journal that has by far been ranked number one in the field of operations research and management over the last two years (Also listed in Business Week). The second illustrates a new and promising combined approach that has been followed within the group. And the third concerns a special paper that has specifically been written for a different discipline (that of blood medicine) to bridge the fields of OR and blood medicine. It has been accepted in 2008 for a leading journal within this field. Secondly, for 2008 also the following objectives were set: More research profiling (e.g. by conferences and presentations). External funding for applied research. As for the first of these objectives an application has been written for an excellence in practice award for the European society of OR. This application is currently under review. Within the same field of research (blood medicine) also a proposal has been written for external PhD funding. Though this application has initially been rejected it was still strongly suggested to resubmit the proposal. 45

4 Last but not least and in line with the weakness as referred to in the SWOT analysis (B10) for the research visitation document, two additional implicit objectives, though not mentioned explicitly as objectives for the 2008 evaluation, were: The completion of at least one PhD. Recruiting of new research staff. As for the first objective, one PhD was completed in December (R.Haijema). As for new staffing the programme has been highly succesfull. Two excellent and younger staff members have been recruited (I.Adan at full professorship and R. Núñez Queija at associate professorship level) SWOT Clearly the group still suffers from small in size with two members close to retirement an insufficient number of Ph.D. s and possibilities for hiring new ones. However, with the two new staff members (which include a.5 fte research time) a major step has been set which seems most promising to start new PhD research as well as to apply for external funding. One threat that remains is that PhD appointments cannot be filled easily. Three evident opportunities in line with a new direction of research are: Further development of analytically based but computationally oriented research with presentday software support, most notably in combination with computer simulation. Fundamental research motivated by selective practical problems (particularly in the field of health care services). Collaboration with other real life institutes in these directions. The theoretical and technical qualities and skills of the program members, the openness and stimulation for practical topics, the collaborations both internally and externally, as well as the enthusiasm and practical contacts are to be seen as strong points for these opportunities. The perspective of the research program as a program for fundamental and practical research can therefore be regarded as quite positive. For 2009 it leads to the following objectives: Objectives for 2009 The continuation of the intial three objectives (interaction, orientation and balanced). The start of new collaborations with the new research members all across the group. The completion of a book editing in an esteemed series of fundamental OR-research. The application for PhD research grants (at least one by 2-nd and one by 3-rd financial support). Another PhD completion (Al-Ibrahim). 6.4 RESOURCES AND FUNDING A 50% external funding is acquired for one PhD. student (AMC). One PhD. student was partially funded by the Dutch Railways (NS). External funding was acquired for one 50% parttime research assistant. (N.Kortbeek). By small practical (research) projects limited external funding has been acquired and used for traveling. 46

5 6.5 OUTPUT Key Publications Dijk, N.M. van & Miyazawa, M. (2004). Error Bounds for Perturbing Nonexponential Queues. Mathematics of Operations Research 29, [A]. Dijk, N.M. van & Sluis, E. van der (2006). Check-In Computation and Optimization by Simulation and IP in Combination, European Journal of Operational Research, 171, [A]. Dijk, N.M. van & Sluis, E. van der (2008). To Pool or not to Pool in Call Centers. Production and Operations Management, 17, [A] Dijk, N.M. van & Sluis, E. van der (2008). Practical Optimization by OR and Simulation. Simulation Modelling Practice and Theory, 16, [B] Duin, C.W. & Sluis, E. van der (2006). On the complexity of Adjacent Resource Scheduling. Journal of Scheduling, 9, [B]. Duin, C.W. & Volgenant, A. (2006). Some inverse optimization problems under the Hamming distance. European Journal of Operational Research, 170, [B] Wal, J. van der & Ormeci, E.L. (2006). Admission Policies for a Two Class Loss System with General Interarrival Times. Stochastic Models, 22, [B]. Forthcoming Adan, I.J.B.F., Bekkers, J.A., Dellaert, N.P., Vissers, J.M.H., Yu, X. (2009). Patient mix optimisation and resource allocation: a case study in cardiothoracic surgery planning. Forthcoming in Health Care Management Science. Adan, I.J.B.F., Haviv, M. (2009). Conditional ages and residual service times in the M/G/1 queue. Forthcoming in Stochastic Models.[B] Adan, I.J.B.F., Economou, A., Kapodistria, S. (2008). Synchronized reneging in queueing systems with vacation. Forthcoming in Queueing Systems.[A] Adan, I.J.B.F., Sleptchenko, A., Houtum, G.J.J.A.N. van (2009). Reducing costs of spare parts supply systems via static priorities. Forthcoming in Asia-Pacific Journal of Operational Research. Adan, I.J.B.F., Mandjes, M., Scheinhardt, W., Tzenova, E. (2009). On a generic class of two-node queueing systems. Forthcoming in Queueing Systems.[A] Boon, M.A.A., Adan, I.J.B.F. (2008). Mixed gated/exhaustive service in a polling model with priorities. Forthcoming in Queueing Systems.[A] Boon, M.A.A., Adan, I.J.B.F., Boxma, O.J. (2009). A two-queue polling model with two priority levels in the first queue. Forthcoming in Value Tools 2008 (Proceedings Third International Conference on Performance Evaluation Methodologies and Tools, Athens, Greece, October 20-24, 2008). Gent: ICST. Boxma, O.J., Van Wijk, A.C.C., Adan, I.J.B.F.(2009). Polling Systems with a Gated/Exhaustive Discipline. Forthcoming in Value Tools 2008 (Proceedings Third International Conference on Performance Evaluation Methodologies and Tools, Athens, Greece, October 20-24, 2008). Gent: ICST. Dijk, N.M. van, Haijema, R., Wal, J,. van der, Smit Sibinga, C. (2009). Blood Platelet Production: A novel approach for practical optimization. Forthcoming in Transfusion. [A-ovb] Dijk, N.M. van & Sluis, E. van der (2009). Call Packing Bound for Overflow Loss Systems. Forthcoming in Performance Evaluation, 66. [A] Dijk, N.M. van & Sluis, E. van der (2009). Pooling is not the answer. Forthcoming in European Journal of Operational Research. [A] Dijk, N.M. & Kortbeek N. (2009). Erlang loss bounds for OK-IC systems, Forthcoming in Queueing Systems [A] Duin, C.W. & Volgenant, A. (2009). Improved polynomial algorithms for robust bottleneck problems with interval data. Forthcoming in Computers & Operations Research. [B] Fralix, B.H., Adan, I.J.B.F. (2009). An infinite-server queue influenced by a semi-markovian environment. Forthcoming in Queueing Systems.[A] 47

6 Haijema, R., Dijk, N.M. van, Wal, J. van der & Smit Sibinga, C. (2009). Blood Platelet Production with Breaks: Optimization by SDP and Simulation. Forthcoming in International Journal on Production Economics. [A] Haijema, R., Dijk, N.M. van, Wal, J. van der & Smit Sibinga, C. (2009). Blood platelet production: a novel approach for practical optimization. Forthcoming in Transfusion. [A] (ovb!-brief volgt) Joustra, P.E., Sluis, E. van der & Dijk, N.M. van (2009). To Pool or not to Pool in Hospitals. Forthcoming in Annals of Operation Research. [B] Selcuk, B., Adan, I.J.B.F., Kok, A.G. de, Fransoo, J.C. (2009). An explicit analysis of the lead time syndrome: stability condition and performance evaluation. Forthcoming in International Journal of Production Research. Verloop, I.M. & Núñez Queija, R. (2009). Achievable performance of resource allocations in bandwidthsharing networks. Forthcoming in Performance Evaluation. 66 (2009), [A] Vlasiou, M., Adan, I.J.B.F., Boxma, O.J. (2009). A two-station queue with dependent preparation and service times. Forthcoming in European Journal of Operational Research, 195(1), Winands, E.M.M., Adan, I.J.B.F., Houtum, G.J.J.A.N. van, Down, D.G. (2009). A state-dependent polling model with $k$-limited service. Forthcoming in Probability in the Engineering and Informational Sciences.[B] Publications in numbers Operations Research & Management ) Academic publications a) in refereed journals A 6 B 6 15 C 3 b) in other journals 1 c) book chapters A - B - 1 C 1 d) proceedings Other 2 Total 19 2) Monographs A - B - 0 C - 3) Ph.D. theses 1 4) Professional publications 0 5) Popular publications 0 6) Working papers 13 Total 33 Dissertations Haijema, R. (2008). Solving large structured Markov Decision Problems for perishable inventory management and traffic control, TI-Research series 444, Uitgeverij Thela Thesis, Amsterdam. Promotors: J.van der Wal & N.M.van Dijk [I] A Academic publications (excluding publications in/of books) refereed Cai, M-C, Duin, C.W., Yang, X., & Zhang, J. (2008). The partial inverse minimum spanning tree problem when weight increase is forbidden. European Journal of Operational Research, 188, [A] Dijk, N.M. van (2008). Error bounds for state space truncation of finite Jackson networks. European Journal of Operational Research, 186, [A] Dijk, N.M. van & Sluis, E. van der (2008). To Pool or not to Pool in Call Centers. Production and Operations Management, 17, [A] Haviv, M.& Wal, J. van der (2008). Mean sojourn times for phase-type discriminatory processor sharing systems, European Journal of Operational Research. [A] 48

7 B C Tzenova, E.I., Adan, I.J.B.F., Kulkarni, V.G. (2008). Output analysis of multiclass fluid models with static priorities. Performance Evaluation, 65, [A] Volgenant, A. (2008). A Note on Parametric Analysis in Linear Assignment. Operations Research, 57, [A] Adan, I.J.B.F., Di Bucchianico, A., Hofstad, R.W. van der (2008). Editorial introduction (Special issue. Eurandom A random tour through a decade of research). Statistica Neerlandica, 2, 255.[B] Adan, I.J.B.F., Kulkarni, V.G. (2008). Insurance risk with variable number of policies. Probability in the Engineering and Informational Sciences, 22, [B] Beekhuizen, P., Denteneer, T.J.J., Adan, I.J.B.F. (2008). Analysis of a tandem network model of a singlerouter Network-on-Chip. Annals of Operations Research, 162, [B] Boxma, O.J., Wal, J. van der, Yechiali, U. (2008). Polling with batch service. Stochastic Models, 24, [B] Edward, G.M., S.F. Das, S.G. Elkhuizen, P.J.M Bakker, J.A.M. Hontelez, M.W. Hollmann, B. Breckel & L.C. Lemaire (2008). Simulation to analyze planning difficulties at the preoperative assessment clinic. British Journal of Anaesthesia (BJA), [B] Hajema, R. & Wal, J. van der (2008). An MDP decomposition approach for traffic control at isolated signalized intersections, Probability and Engineering in the Informational Sciences. [B] Dijk, N.M. van & Sluis, E. van der (2008). Bounds for Simulation. Journal of Simulation, 2, Dijk, N.M. van & Sluis, E. van der (2008). Practical Optimization by OR and Simulation. Simulation Modelling Practice and Theory, 16, Kock, A.A.A., Wullems, F.J.J., Etman, L.F.P., Adan, I.J.B.F., Nijsse, F., Rooda, J.E. (2008). Performance measurement and lumped parameter modeling of single server flow lines subject to blocking : an effective process time approach. Computers & Industrial Engineering, 54(4), C Academic publications (in/of books) refereed Opp, M., Adan, I.J.B.M., Kulkarni, V.G., Swaminathan, J.M. (2008). Allocating Outsourced Warranty Service Contracts In Outsourcing, Teamwork and Business Management. Ed. Karl E. Carettas. Nova Science Publishers, Hauppauge NY [C] Academic publications (in proceedings) non-refereed Dijk, N.M. van & Kortbeek, N. (2008). On Dimensioning Intensive Care Units. To appear: Operations Research Proceedings 2007, Springer. Núñez Queija, R. & Prabhu, B.J. (2008). Scaling laws for file dissemination in P2P networks with random contacts. Proceedings of IWQoS International Workshop on Quality of service 2008, IEEE Xplore Digital Object Identifier /IWQOS [Rating??] Academic publications (excluding publications in/of books) non-refereed Volgenant, A. (2008). An addendum on the incremental assignment problem, Information Sciences, 178, Academic publications (working- and discussion papers) Adan, I.J.B.F., Foley, R.D., McDonald, D.R. (2008). Exact asymptotics for the stationary distribution of a Markov chain: A production model. Eurandom Report No , Eindhoven: Eurandom, 33 pp. Adan, I.J.B.F., Haviv, M. (2008). Conditional ages and residual service times in the M/G/1 queue. Eurandom Report No , Eindhoven: Eurandom, 20 pp. 49

8 Adan, I.J.B.F., Mandjes, M.R.H., Scheinhardt, W.R.W., Tzenova, E.I. (2008). On a generic class of twonode queueing systems. Eurandom Report No , Eindhoven: Eurandom, 24 pp. Boon, M.A.A., Adan, I.J.B.F., Boxma, O.J. (2008). A two-queue polling model with two priority levels in the first queue. Eurandom Report No , Eindhoven: Eurandom, 22 pp. Boon, M.A.A., Adan, I.J.B.F., Boxma, O.J. (2008). A polling model with multiple priority levels. Eurandom Report No , Eindhoven: Eurandom, 28 pp. Dijk, N.M. van (2008). On Practical Product Form Characterization. Part I Product Forms: Single Station Hierarchy; Part II Product Forms: Tandem and Cluster Structures. AE-Report 4/2008. Dijk, N.M. van (2008). Error Bounds and Comparison Results:The Markov Reward Approach for Queueing Networks. Part I Motivation and general results; Part II Applications. AE-Report 5/2008. Kock, A.A.A., Etman, L.F.P., Rooda, J.E., Adan, I.J.B.F., Vuuren, M. van, Wierman, A.C. (2008). Aggregate modeling of multi-processing workstations. Eurandom Report No , Eindhoven: Eurandom, 23 pp. Fralix, B.H., Adan, I.J.B.F. (2008). An infinite-server queue influenced by a semi-markovian environment. Eurandom Report No , Eindhoven: Eurandom, 15 pp. Joustra, P.E., Kolfin, R., Dijk, N.M. van, Koning, C.C.E. & Bakker, P.J.M. (2009). Efficiency improvement by capacity variability reduction: A case study for a radiotherapy process AE-Report 2/2008. Kortbeek, N., Wal, J. van der, Dijk, N. M. van, Haijema, R. and Kort, W. de. (2008). Bloodbank production and issuing Optimization: Strategies for younger platelets, submitted to International Journal of Production Economics. AE-Report 3/2008. Verloop, I.M. & Núñez Queija, R. (2008). Asymptotically optimal parallel resource assignment with interference. CWI Research Report, PNA-E0805. Volgenant A. (2008). On finding all the optimal linear assignment solutions. AE-Report 1/2008. Contributions to academic conferences, workshops and seminars Adan, I.J.B.F. (September 25, 2008). Performance evaluation of warehousing and manufacturing systems: aggregation and decomposition techniques. The third Biennial Beta conference Lecture. Adan, I.J.B.F. (October 12, 2008). An Infinite-server Queue in a Semi-Markov Environment. INFORMS Annual Meeting 2008 Washington, DC. Lecture. Adan, I.J.B.F. (October 12, 2008). Approximate Mean Value Analysis of Closed Queueing Networks with Bulk Servers. L. Liu, I. Adan. INFORMS Annual Meeting 2008 Washington, DC. Lecture. Adan, I.J.B.F. (October 12, 2008). Performance Analysis of Production Lines with No Buffers. I. Adan. INFORMS Annual Meeting 2008 Washington, DC. Session Chair. Dijk, N.M. van (March 7, 2008). Blood platelet production with spill and age optimization. 15 th International Seminar on Production Economics, Innsbruck, Austria. Lecture. Dijk, N.M. van (November 18, 2008). On dimensioning IC-units. Conference Operations Research & Health Care 2008, NGB working group Operations Research and Health care, Erasmus University Rotterdam. Lecture. Haijema, R. (September 3, 2008). An MDP approximation for clever traffic lights that use arrival information. Operations Research 2008, GOR, Augsburg, Germany.Lecture. Haijema, R. (October 12, 2008). MDP and Simulation for Efficient Blood Platelet Production and Improved Platelet Transfusion. INFORMS Annual Meeting 2008, Washington DC. Lecture. Haijema, R. (November 18, 2008). TIMO: A decision support tool for efficient blood platelet production, Part I Methodology. Conference Operations Research & Health Care 2008, NGB working group Operations Research and Health care, Erasmus University Rotterdam. Lecture. Haijema, R. (November 21, 2008). An MDP approach for the dynamic control of traffic lights. Queueing Colloquium, CWI, Amsterdam. Lecture. Núñez Queija, R. (2008, April 25). Scalability of random peer to peer networks. Queueing Colloquium, Amsterdam, The Netherlands, Lecture. Kortbeek, N. (November 18, 2008). TIMO: A decision support tool for efficient blood platelet production, Part II Strategies for younger platelets. Conference Operations Research & Health 50

9 Care 2008, NGB working group Operations Research and Health care, Erasmus University Rotterdam. Lecture. Núñez Queija, R. (2008, June 2). Scaling laws for file dissemination in P2P networks with random contacts. IWQoS international Workshop on Quality of Service 2008, Twente, The Netherlands, Lecture. Núñez Queija, R. (2008, July 24). Resource allocation in bandwidth-sharing networks. Research Seminar LAAS- CNRS, Toulouse, France, Invited lecture. Sluis, E. van der (2008, 23 August). Economic Lot Scheduling Problems with new and different cost approximations. 15 th International Symposium on Inventories. Budapest, Hungary. Lecture. Organisational contributions to conferences, workshops and seminars Adan, I.J.B.F. (2008). TPC member of NET-COOP nd Workshop on Network Control and Optimization September Adan, I.J.B.F. (2008). TPC member of SMCTools The 3rd International Workshop on Tools for solving Structured Markov Chains. Athens, Greece. October 20, Núñez Queija, R.. Organizer of the national Queueing Colloquium (April 25 and November 21). Núñez Queija, R.. Technical Program Committee member for: ACM SIGMETRICS 2008 (Annapolis, Maryland), Euro-NGI Workshop on Wireless and Mobility 2008 (Sitges, Spain), IWQoS 2008 International Workshop on Quality of Service (Twente, The Netherlands), MAMA 2008 International Workshop on Matrix Analytical Methods and Analysis (Annapolis, Maryland), NGI 2008 International Conference on Next Generation Internet (Krakow, Poland), ValueTools 2008 (Athens, Greece) Participation in academic networks & fellowships Adan, I.J.B.F. (2008). Member LNMB (Landelijk Netwerk Mathematische Besliskunde). Dijk, N.M. van (2008). Member LNMB (Landelijk Netwerk Mathematische Besliskunde) and ORSA (Operations Research Society of America). Núñez Queija, R. (2008). Member of IFIP (Working Group 7.3), Stieltjes Institute and LNMB (Landelijk Netwerk Mathematische Besliskunde). Sluis, H.J. (2008). Member of INFORMS (Institute for Operations Research and the Management Sciences) and ISIR (International Society for Inventory Research). Volgenant, A. (2008). Member LNMB (Landelijk Netwerk Mathematische Besliskunde). Wal, J. van der (2008). Member LNMB (Landelijk Netwerk Mathematische Besliskunde). Editor or member of editorial board Adan, I.J.B.F. (2008). Editor of Queueing Systems, Statistica Neerlandica, Mathematical Methods of Operations Research. Adan, I.J.B.F. (2008). Area Editor of Asia-Pasific Journal of Operations Research. Adan, I.J.B.F. (2008). Guest Editor of Special Issue of Statistica Neerlandica: Eurandom A random tour through a decade of research. Núñez Queija, R. (2008). Associate editor of Mathematical Methods of Operations Research, Operations Research Letters. Núñez Queija, R. (2008). Guest editor (joint with M.R.H. Mandjes and R.D. van der Mei) of Stochastic Performance Models for Resource Allocation in Communication Systems. Special Issue of Annals of Operations Research. Publication in Volgenant, A. (2008). Advisory editor of Computers & Operations Research Referee activities Dijk, N.M. van (2008). Referee for Operations Research, Journal of Applied Probability, Advances in Applied Probability, Production and Operations Management, European Journal of Operational Research.,Queueing Systems Duin, C.W. (2008). Referee for Computers & Operations Research, European Journal of Operational Research. Haijema, R. (2008). Referee for Computers & Operations Research, Interfaces. 51

10 Núñez Queija, R. (2008). Referee for journals: Journal of Applied Probability, Journal of Communications and Networks, Mathematical Methods of Eperations Research, Operations Research, Operations Research Letters, Performance Evaluation, Queueing Systems. Núñez Queija, R. (2008). Referee for conferences: International Teletraffic Congress, INFOCOM, Performance Evaluation. Sluis, E. van der (2008). Referee for International Journal on Production Economics. Volgenant, A. (2008). Referee for European Journal of Operational Research, Journal of the Operational Research Society. Wal, J. van der (2008). Referee for Queueing Systems. Membership of academic committees (including Ph.D. committees outside the FEB) Adan, I.J.B.F. (2008). Invited external member promotion committee of J. Van Velthoven. Promotor: prof. B. Van Houdt, prof. C. Blondia. Universiteit Antwerpen. Adan, I.J.B.F. (2008). Invited member promotion committee of A.A.A. Kock. Promotor: prof. K. Rooda, prof. O.J. Boxma. Technische Universiteit Eindhoven. Adan, I.J.B.F. (2008). Invited member promotion committee of G.Z. Mincsovics. Promotor: prof. J.W.M. Bertrand, prof. J. van der Wal. Technische Universiteit Eindhoven. Núñez Queija, R. (2008). Member of Ph.D. thesis committee of P.M.D. Lieshout, September 5, University of Amsterdam. Wal, J.van der (2008). Copromotor of G.Z. Mincsovics, Technische Universiteit Eindhoven Wal, J.van der (2008). Invited member promotion committee of P.Lieshout, University of Amsterdam Various activities Dijk, N.M. van (2008). Wachten in de zomer, Vrij Nederland, August 2, Dijk, N.M. van, Greuter, J. (2008). To Wait or Not to Wait, Edition, December 2008, Dijk, N.M. van, Jansma, F. & Kortbeek, N. (2008). Vitally Important Optimizations TIMO: Thrombocytes Inventory Managament, Edition, December 2008, Núñez Queija, R. (2008). Answer to the question Why are trains always late? in the radio program De Kettingvraag on Radio 5, June