University of Patras Department of Mathematics

Ioannis Dimitriou
Department of Mathematics
University of Patras
26500, Patras, Greece

Office: B/M 232
Email: idimit@math.upatras.gr
Phone: +302610 996774
Fax:

Position Lecturer
Organization University of Patras
Department Mathematics
Division Statistics, Probability and Operational Research

Biography

Since July 2014, I am a Lecturer at the Dept of Mathematics, University of Patras, Greece. I was appointed as a postdoctoral researcher at the Dept. of Electrical and Electronic Engineering, Imperial College, London, UK (October 2011-July 2012), at FORTH, Greece (September 2013-July 2014), at the Dept. of Mathematics, Aristotle University of Thessaloniki, Greece (Postdoc fellowship awarded by the Research Committee of AUTH, January-December 2013) and at INRIA, Sophia Antipolis (MAESTRO) through the ABCDE ERCIM fellowship program (May-July 2014, Marie Curie Actions).


Research interests

My research interests focus on queueing theory, applied probability, stochastic processes, and performance modelling of computer and communication networks.


Publications

Papers in Journals/Chapters

  1. I. Dimitriou, (2018). A two-class queueing system with constant retrial policy and general class dependent service times. European Journal of Operational Research 270 (3), pp. 1063-1073 [arXiv:1802:07451].
  2. I. Dimitriou, N. Pappas, (2018). Stable Throughput and Delay Analysis of a Random Access Network With Queue-Aware Transmission. IEEE Transactions on Wireless Communications 17 (5), pp. 3170-3184 [arXiv:1704:02902]
  3. N. Pappas, Z. Chen, I. Dimitriou, (2018). Throughput and Delay Analysis of Wireless Caching Helper Systems with Random Availability. IEEE Access 6 (1), pp. 9667-9678.
  4. E. Morozov, I. Dimitriou, (2017). Stability Analysis of a Multiclass Retrial System with Coupled Orbit Queues. Springer Verlag Lecture Notes in Computer Science (LNCS), vol. 10497, pp. 85-98.
  5. I. Dimitriou, N. Pappas, (2017). Stable Throughput and Delay Analysis of a Channel-Aware Adaptive Random Access Wireless Network. Springer Verlag Lecture Notes in Computer Science (LNCS), vol. 10378, pp. 63-80.
  6. I. Dimitriou, (2017). Modeling and Analysis of a Relay-Assisted Cooperative Cognitive Network. Springer Verlag Lecture Notes in Computer Science (LNCS), vol. 10378, pp. 47-62.
  7. I. Dimitriou, (2017). Dynamic balancing in finite processor sharing queues with guard bandwidth policy, multiclass retrial users and signals. Performance Evaluation 114, pp. 1-15.
  8. I. Dimitriou, (2017). A queueing system for modeling cooperative wireless networks with coupled relay nodes and synchronized packet arrivals. Performance Evaluation 114, pp. 16-31.
  9. I. Dimitriou, (2017). A two class retrial system with coupled orbit queues. Probability in the Engineering and Informational Sciences 31 (2), pp. 139-179.
  10. G. Fortetsanakis, I. Dimitriou, M. Papadopouli, (2017). A Game-Theoretical Analysis of Wireless Markets using Network Aggregation. IEEE Transactions on Mobile Computing 16(3), pp. 602-616.
  11. I. Dimitriou, (2016). A retrial queue to model a two-relay cooperative wireless system with simultaneous packet reception. Springer Verlag Lecture Notes in Computer Science (LNCS), vol. 9845, pp 123-139.
  12. I. Dimitriou, (2016). A queueing model with two types of retrial customers and paired services. Annals of Operations Research 238 (1), pp. 123-143.
  13. I. Dimitriou, (2016). Queueing analysis of the DRX power saving mechanism in fault-tolerant 3GPP LTE wireless networks. Annals of Operations Research 239(2), pp. 521-552
  14. I. Dimitriou, S. Alouf, A. Jean-Marie, (2015). A Markovian queueing system for modeling a smart green base station. Springer Verlag Lecture Notes in Computer Science (LNCS), vol 9272, pp. 3-18.
  15. I. Dimitriou, (2015). Performance modeling of cellular systems with nite processor sharing queues in random environment, guard policy and flex retrial users. Springer Verlag Lecture Notes in Computer Science (LNCS), vol 9081, pp. 43-58.
  16. I. Dimitriou, (2015). A retrial queue for modelling fault-tolerant performance systems with checkpointing and rollback-recovery. Computers & Industrial Engineering, vol 79, pp. 156-167.
  17. I. Dimitriou, (2014). A queueing system with probabilistic inhomogeneous vacations for modeling power-saving in wireless systems with retransmissions. In: Czachorski T., Gelenbe E., Lent R. (eds) Information Sciences and Systems 2014. Springer, Cham.
  18. I. Dimitriou, (2014). A modified vacation queueing model and its application on the Discontinuous Reception power saving mechanism in unreliable Long Term Evolution networks. Performance Evaluation, vol 77, pp. 37-56.
  19. I. Dimitriou, (2013). A batch arrival priority queue with recurrent repeated demands, admission control and hybrid failure recovery discipline. Applied Mathematics and Computation, vol 219 (24), pp 11327-11340.
  20. I. Dimitriou. (2013). A mixed priority retrial queue with negative arrivals, unreliable server and multiple vacations. Applied Mathematical Modelling, vol 37(3), pp 1295-1309.
  21. I. Dimitriou, (2013). Analysis of a priority retrial queue with dependent vacation scheme and application to energy saving in wireless communication systems. The Computer Journal, vol 56 (11), pp 1363-1380 (online first 2012).
  22. I. Dimitriou. (2013). A preemptive resume priority retrial queue with state dependent arrivals, unreliable server and negative customers. TOP, vol 21 (3), pp 542-571 (online first 2011).
  23. C. Langaris, I. Dimitriou. (2010). A queueing system with n-phases of service and (n-1)-types of retrial customers, European Journal of Operational Research, vol 205, Issue 3, pp 638-649.
  24. I. Dimitriou, C. Langaris. (2010). A repairable queueing model with two-phase service, start-up times and retrial customers, Computers and Operations Research, vol 37, Issue 7, pp 1181-1190.
  25. I. Dimitriou, C. Langaris. (2009). A queueing model with start-up/close-down times and retrial customers, Stochastic Models, vol 25, Issue 2, pp 248-269.
  26. I. Dimitriou, C. Langaris. (2008). Analysis of a retrial queue with two-phase service and server vacations, Queueing Systems, vol 60 (1-2), pp 111-129.

Submitted/Under review

  1. N. Pappas, I. Dimitriou, Z. Chen, Network-level Cooperation in Random Access IoT Networks with Aggregators. Under submission, September 2018.
  2. M. Saxena, I. Dimitriou, S. Kapodistria, Analysis of the shortest relay queue policy in a cooperative random access network with collisions. Under submission, September 2018.
  3. I. Dimitriou, Delay analysis of a dynamic queue-based random access network, Submitted, September 2018.
  4. I. Dimitriou, On the power series approximations of a structured batch arrival two-class retrial system with weighted fair orbit queues, Submitted, June 2018
  5. I. Dimitriou, N. Pappas, Performance Analysis of a Cooperative Wireless Network with Adaptive Relays, Submitted, January 2018.

Papers in refereed conferences

  1. E, Morozov, T. Morozova, A. Rumyantsev, I. Dimitriou, (2018). Stability analysis and simulation of a multiclass retrial system with coupled orbit queues. In DCCN 2018, 17-21 September 2018, Moscow, Russia.
  2. N. Pappas, I. Dimitriou, Z. Chen, (2018). Network-level Cooperation in Random Access IoT Networks with Aggregators. Accepted in the 30th International Teletraffic Congress, Vienna, Austria, 4 - 7 September 2018 (Proceedings in IEEE Explore)
  3. M. Saxena, I. Dimitriou, S. Kapodistria, (2018) Analysis of the shortest relay queue policy in a cooperative random access network. Accepted for presentation in the 3nd European Conference on Queueing Theory (ECQT 2018), Jerusalem, Israel, 2-4 July 2018.
  4. I. Dimitriou, (2018). Performance modelling of a two-user interference-limited random access network with collisions. Accepted in the Stochastic Networks Conference 2018, Poster session, Edinburgh, UK, June 25-29, 2018.
  5. I. Dimitriou, (2018). Queueing models with state-dependent parameters: New results and applications to next generation communication networks. Accepted in the 7th meeting of the EURO Working Group on Stochastic Modelling (StochMod 2018), Lancaster, UK, June 13-15, 2018.
  6. I. Dimitriou, K. Katsanou, (2018). Stationary analysis of an adaptive two-class retrial system under the join the shortest orbit queue policy. Accepted in the 7th meeting of the EURO Working Group on Stochastic Modelling (StochMod 2018), Lancaster, UK, June 13-15, 2018.
  7. I. Dimitriou, N. Pappas, (2018). Performance Analysis of an Adaptive Queue-Aware Random Access Scheme with Random Traffic. Accepted for presentation in IEEE ICC 2018 Wireless Networking Symposium (Acceptance rate 39.99%).
  8. I. Dimitriou, T. Phung-Duc, (2018). A Riemann-Hilbert boundary value problem for single-server systems with two queues for blocked and feedback customers. AIP Conference Proceedings 1978 (1), 190004 (2018); https://doi.org/10.1063/1.5043831
  9. E. Morozov, I. Dimitriou, (2017). Stability Analysis of a Multiclass Retrial System with Coupled Orbit Queues. Accepted for presentation in the 14th European Workshop on Performance Engineering (EPEW 2017) Berlin, Germany, September 7-8 2017.
  10. I. Dimitriou, (2017). A system with coupled processors and simultaneous arrivals. AIP Conference Proceedings 1863, 200007 (2017); doi: http://dx.doi.org/10.1063/1.4992378 (Proceedings of SAMMA 2016, ICNAAM)
  11. I. Dimitriou, N. Pappas, (2017). Stable Throughput and Delay Analysis of a Channel-Aware Adaptive Random Access Wireless Network. Accepted in the 24rd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle, UK.
  12. I. Dimitriou, (2017). Performance analysis of a relay-assisted cooperative cognitive network. Accepted in the 24rd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle, UK.
  13. I. Dimitriou, (2016). A retrial queue to model a two-relay cooperative wireless system with simultaneous packet reception. Accepted in the 23rd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2016), Cardiff, Wales, UK. 24-26 August 2016.
  14. I. Dimitriou, (2016). Two-class retrial queues for modeling cooperative wireless networks with coupled relay nodes, Accepted for presentation in the 11th International Workshop on Retrial queues (WRQ 2016), Amsterdam, Netherlands, August 31-September 2, 2016.
  15. I. Dimitriou, (2016). A queueing system to model cooperative wireless networks with coupled relay nodes and simultaneous packet reception. Accepted for presentation in the 2nd European Conference on Queueing Theory (ECQT 2016), Toulouse, France, 18-20 July 2016.
  16. I. Dimitriou, (2015). A two-class retrial system with coupled orbit queues. 18th INFORMS Applied Probability Conference held on the campus of Koc University in Istanbul, Turkey. July 5th - 8th, 2015 .
  17. I. Dimitriou, S. Alouf, A. Jean-Marie, (2015). A Markovian queueing system for modeling a smart green base station. Presented in the 12th European Workshop on Performance Engineering (EPEW 2015) Madrid, Spain, 31 August and 1 September, 2015.
  18. I. Dimitriou, (2015). Performance modeling of cellular systems with nite processor sharing queues in random environment, guard policy and ex retrial users. Presented in 22nd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2015), Albena, Bulgaria, 26-29 May 2015.
  19. I. Dimitriou, (2015). On a two coupled processor system with negative customers. 10th International Conference on Stochastic Models of Manufacturing and Service Operations - SMMSO 2015, Volos, Greece, 1-6 June 2015.
  20. I. Dimitriou, (2014). A retrial queue with two-types of customers and paired services. Accepted for presentation at the First European Conference on Queueing Theory (ECQT 2014), Ghent, Belgium, 20-22 August 2014.
  21. I. Dimitriou, (2014). A queueing system with probabilistic inhomogeneous vacations for modeling power-saving in wireless systems with retransmissions. Accepted for presentation at the 29th International Symposium on Computer and Information Sciences, Krakow, Poland, October 27-28th, 2014.
  22. I. Dimitriou, (2012). Analysis of a priority retrial queue with dependent vacation scheme and application to energy saving in wireless communication systems. Presented in 9th International Workshop on Retrial Queues (WRQ), Pablo de Olavide University, Seville, Spain, 28-30 June 2012.
  23. I. Dimitriou, (2012). An unreliable vacation queueing model and its application on the DRX mechanism for power saving in 3GPP LTE. Imperial College Energy and Performance Colloquium (ICEP 2012), Imperial College London, 29 May-1 June 2012.
  24. I. Dimitriou, C. Langaris, (2008). A queueing system with n phases of service, vacations and retrial customers. 7th International Workshop on Retrial Queues, Athens, Greece, July 17-19, 2008.

Other publications

  1. I. Dimitriou. (2009). A gated type multiclass retrial queue with structured batch arrivals, priorities and vacations. Technical Report, Department of Mathematics, University of Ioannina, Number 20, Volume June-December 2009, pp 1-13.
  2. I. Dimitriou. (2012). A multiserver queue with vacations and timers in Markovian environment for managing energy consumption in data centers. Imperial College, Technical report, May 2012.

Referee for Journals

I am a regular reviewer for the following peer review journals

  • Computers and Operations Research
  • Journal of Systems Science and Systems Engineering
  • Central European Journal of Operational Research
  • Applied Mathematical Modelling
  • Operational Research
  • Queueing Systems
  • Asia Pacific Journal of Operational Research
  • Mathematical and Computer Modelling
  • International Journal of Computer Mathematics
  • Quality Technology and Quantitative Management
  • IEEE Transactions on Wireless Communications
  • IEEE Communication Letters
  • IEEE Transactions on Communications
  • IEEE Transactions on Mobile Computing
  • Annals of Operations Research
  • KSII Transactions on Internet and Information Systems
  • Performance Evaluation
  • Applied Mathematics and Computation
  • European Journal of Operational Research
  • Computers and Industrial Engineering
  • Computer Networks
  • RAIRO - Operations Research
  • ACM Transactions on Modeling and Performance Evaluation of Computing Systems (TOMPECS)
  • Methodology and Computing in Applied Probability
  • SIAM Journal on Applied Mathematics
  • Annals of Telecommunications
  • International Journal of Applied Mathematics and Computer Science (AMCS)
  • Journal of Industrial and Management Optimization
  • International Journal of Computer Mathematics: Computer Systems Theory

    Edited Conference proceedings

  • Phung-Duc, T. and Dimitriou, I., Eds., Proceedings of Symposium on Stochastic Models: Methods and Applications (SAMMA 2016 within the ICNAAM 2016, Rhodes, Greece, 19-25 September 2016.), AIP Conference Proceedings, Vol. 1863, 200001, 2017. [DOI: 10.1063/1.4992372]
  • Phung-Duc, T. and Dimitriou, I. and Vatamidou, E. Eds., Proceedings of Symposium on Stochastic Models: Methods and Applications (SAMMA 2017 within the ICNAAM 2017, 25-30 September 2017, Thessaloniki, Greece.), AIP Conference Proceedings 1978(1):190001. [DOI: 10.1063/1.5043828]

    Contribution to International Conferences

  • Program Committee Member for the European Simulation and Modelling conference (ESM 2018) to be held in Ghent, Belgium, October 2018.
  • Program Committee Member for the 23rd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2016), Cardiff, UK.
  • Co-Organizer of the 1st Symposium on Stochastic Models: Methods and Applications (SAMMA 2016), 14th International Conference of Numerical Analysis and Applied Mathematics, 19-25 September 2016, Rodos Palace Hotel, Rhodes, Greece (with with Dr. Tuan Phung-Duc (Tokyo Institute of Technology, Tokyo, Japan)).
  • Program Committee Member for the 24rd International Conference on Analytical & Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle UK.
  • Co-Organizer of the 2nd Symposium on Stochastic Models: Methods and Applications (SAMMA 2017), 15th International Conference of Numerical Analysis and Applied Mathematics, 25-30 September 2016, The MET Hotel, Thessaloniki, Greece (with with Dr. Tuan Phung-Duc (Tokyo Institute of Technology, Tokyo, Japan), and Dr. Eleni Vatamidou University of Lausanne, Switzerland) ).

    Referee for Research Proposals

  • Research Foundation -- Flanders (FWO), Belgium (2017, 2018) [Website. ].
  • Hellenic Foundation for Research and Innovation (HFRI), Greece (2017, Research Projects for Postdoctoral Researchers) [Website. ].

    Invited talks

  • I. Dimitriou. (2016). Two-class retrial queues for modeling cooperative wireless networks with coupled relay nodes. MAESTRO group, INRIA, 7 September 2016
  • I. Dimitriou. (2013). Multiclass retrial queues with preemptive priorities. Invited talk in the 7th Young European Queueing Theorists (YEQT IIV) workshop held in EURANDOM/TU Eindhoven in November 4-5-6, 2013.
  • I. Dimitriou. (2013). Performance Analysis of the Discontinuous Reception (DRX) power saving method in 3GPP LTE: A queueing perspective. FORTH-Institute of Computer Science, Herakleion-Greece, 24 January 2013.
  • I. Dimitriou. (2012). Applied probability applications. Department of Mathematical Sciences. University of Essex, 20 March 2012.
  • I. Dimitriou. (2011). Mixed priority retrial queues with negative arrivals. Department of Mathematics, University of Ioannina, Greece,

    Invited visits

  • Inria, MAESTRO Group, Sophia-Antipolis, France. September 4-9, 2016. Host: K. Avrachenkov.
  • TU/e, Stochastics Group, Eindhoven, Netherlands. May 28-June 11, 2017. Host: S. Kapodistria, O. Boxma.

    Grants/scholarships

  • June 2018. Awarded Travel Grant to participate in the 7th meeting of the EURO Working Group on Stochastic Modelling (StochMod 2018), Lancaster, UK, June 13-15, 2018.
  • Marie Curie Fellow, ERCIM Alain Bensoussan Fellowship Programme, co-funded by the European Commission under the FP7 Marie-Curie action named ABCDE.
  • Post Doctoral fellowship 'Research Excellence', 1/1/2013-31/12/2013, Aristotle University of Thessalonica Research Commitee, Hosting Department: Department of Mathematics, Scientific Coordinator: Professor George Tsaklidis.
  • Supported from State Scholarships Foundation of Greece (IKY) for MSc and PhD Degree at Mathematics Department, University of Ioannina, Greece (2004-2005, 2006-2008).

    Academic Societies

    EURO Working Group on Stochastic Modelling

    Professional member (no 6271326) of the Association for Computing Machinery (ACM)


    Teaching activities

    Undergradute courses

  • Introduction to Stochastic Processes (2014-,Dept. of Mathematics, Univ. of Patras).
  • Introduction to Queueing Theory (2015-Dept. of Mathematics, Univ. of Patras).
  • Probability theory and Stochastic processes (2014-,Dept. of Material Sciences, Univ. of Patras)
  • Mathematics I (2014-2015, Dept. of Geology, Univ. of Patras)

    Postgradute courses

  • Stochastic Processes (MSc program on "Computer and Decision Mathematics", co-organized with Computer Engineering & Informatics Department), 2014-2018.
  • Operations Research (MSc program on "Computer and Decision Mathematics", co-organized with Computer Engineering & Informatics Department), 2014-2018.
  • Queueing Systems (MSc program on "Computer and Decision Mathematics", co-organized with Computer Engineering & Informatics Department), 2014-2018.
  • Data-driven Probabilistic Models in Decision Making Process (MSc program on Computational Data Science and Statistical Analytics (MCDA)). Dept. of Mathematics, University of Patras, Greece, 2018- Syllabus.

    Students

    Completed MSc students

  • E. Zisimopoulou, (2016). Retrial queueing systems : a review and an application. (MSc Thesis, in Greek, Nemertes DSpace).
  • M. Markou, (2016). On queueing models with impatient customers in random environment : an overview and an application. (MSc Thesis, in Greek, Nemertes DSpace).
  • A. Kaltsas, (2016). Vacation queuing models with applications in energy saving. (MSc Thesis, in Greek, Nemertes DSpace).
  • K. Katsanou, (2018). Performance analysis of a cooperative wireless network (completed).

    Ongoing MSc students

  • A. Mantzios, (2017). Queueing models with multiple waiting lines (ongoing).

    Completed BSc students

  • I. Ktorides, (2017). Markovian queueing models with applications to relay-assisted networks.
  • D. Kintos, (2017). Birth-death queueing systems and the method of phases.
  • G. Vasilakopoulos, (2018). Game theoretical aspects of queueing theory.

    Miscellaneous

    For more information see my pages in Google Scholar, ReaserchGate, Academia, Linkedin

    Last modified: September, 17, 2018