


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. Previously, I was appointed as a postdoctoral researcher at the Dept. of Electrical and Electronic Engineering, Imperial College, London, UK (October 2011July 2012),
at FORTH, Greece (September 2013July 2014), at the Dept. of Mathematics, Aristotle University of Thessaloniki, Greece (Postdoc fellowship awarded by the Research Committee of AUTH, JanuaryDecember 2013) and at INRIA,
Sophia Antipolis (MAESTRO) through the ABCDE ERCIM
fellowship program (MayJuly 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
 I. Dimitriou, (2018). A twoclass queueing system with constant retrial policy and general class dependent service times. European Journal of Operational Research 270 (3), pp. 10631073 [arXiv:1802:07451].
 I. Dimitriou, N. Pappas, (2018). Stable Throughput and Delay Analysis of a Random Access Network With QueueAware Transmission. IEEE Transactions on Wireless Communications 17 (5), pp. 31703184 [arXiv:1704:02902]
 N. Pappas, Z. Chen, I. Dimitriou, (2018). Throughput and Delay Analysis of Wireless Caching Helper Systems with Random Availability. IEEE Access 6 (1), pp. 96679678.
 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. 8598.
 I. Dimitriou, N. Pappas, (2017). Stable Throughput and Delay Analysis of a ChannelAware Adaptive Random Access Wireless Network. Springer Verlag Lecture Notes in Computer
Science (LNCS), vol. 10378, pp. 6380.
 I. Dimitriou, (2017). Modeling and Analysis of a RelayAssisted Cooperative Cognitive Network. Springer Verlag Lecture Notes in Computer
Science (LNCS), vol. 10378, pp. 4762.
 I. Dimitriou, (2017). Dynamic balancing in finite processor sharing queues
with guard bandwidth policy, multiclass retrial users
and signals. Performance Evaluation 114, pp. 115.
 I. Dimitriou, (2017). A queueing system for modeling cooperative wireless networks with coupled relay nodes and synchronized packet arrivals. Performance Evaluation 114, pp. 1631.
 I. Dimitriou, (2017). A two class retrial system with coupled orbit queues. Probability in the Engineering and Informational Sciences 31 (2), pp. 139179.
 G. Fortetsanakis, I. Dimitriou, M. Papadopouli, (2017). A GameTheoretical Analysis of Wireless Markets using Network Aggregation. IEEE Transactions on Mobile Computing 16(3), pp. 602616.
 I. Dimitriou, (2016). A retrial queue to model a tworelay cooperative wireless system with simultaneous packet reception. Springer Verlag Lecture Notes in Computer
Science (LNCS), vol. 9845, pp 123139.
 I. Dimitriou, (2016). A queueing model with two types of retrial customers and
paired services. Annals of Operations Research 238 (1), pp. 123143.
 I. Dimitriou, (2016). Queueing analysis of the DRX power saving mechanism in faulttolerant 3GPP LTE wireless networks. Annals of Operations Research 239(2), pp. 521552
 I. Dimitriou, S. Alouf, A. JeanMarie, (2015). A Markovian queueing system for
modeling a smart green base station. Springer Verlag Lecture Notes in Computer
Science (LNCS), vol 9272, pp. 318.
 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. 4358.
 I. Dimitriou, (2015). A retrial queue for modelling faulttolerant performance systems with checkpointing and rollbackrecovery. Computers & Industrial Engineering, vol 79, pp. 156167.
 I. Dimitriou, (2014). A queueing system with probabilistic inhomogeneous vacations for modeling powersaving in wireless systems with retransmissions. In: Czachorski T., Gelenbe E., Lent R. (eds) Information Sciences and Systems 2014. Springer, Cham.
 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. 3756.
 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 1132711340.
 I. Dimitriou. (2013). A mixed priority retrial queue with negative arrivals, unreliable server and multiple vacations. Applied Mathematical Modelling, vol 37(3), pp 12951309.
 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 13631380 (online first 2012).
 I. Dimitriou. (2013). A preemptive resume priority retrial queue with state dependent arrivals, unreliable server and negative customers. TOP, vol 21 (3), pp 542571 (online first 2011).
 C. Langaris, I. Dimitriou. (2010). A queueing system with nphases of service and (n1)types of retrial customers, European Journal of Operational Research, vol 205, Issue 3, pp 638649.
 I. Dimitriou, C. Langaris. (2010). A repairable queueing model with twophase service, startup times and retrial customers, Computers and Operations Research, vol 37, Issue 7, pp 11811190.
 I. Dimitriou, C. Langaris. (2009). A queueing model with startup/closedown times and retrial customers, Stochastic Models, vol 25, Issue 2, pp 248269.
 I. Dimitriou, C. Langaris. (2008). Analysis of a retrial queue with twophase service and server vacations, Queueing Systems, vol 60 (12), pp 111129.
Submitted/Under review
 N. Pappas, I. Dimitriou, Z. Chen, Networklevel Cooperation in Random Access IoT Networks with Aggregators. Under submission, September 2018.
 M. Saxena, I. Dimitriou, S. Kapodistria, Analysis of the shortest relay queue policy in a cooperative random access network with collisions. Submitted, October 2018.
 I. Dimitriou, Delay analysis of a dynamic queuebased random access network, Submitted, September 2018.
 I. Dimitriou, On the power series approximations of a structured batch arrival twoclass retrial system with weighted fair orbit queues, Submitted, June 2018
 I. Dimitriou, N. Pappas, Performance Analysis of a Cooperative Wireless Network with Adaptive Relays, Submitted revised version, 1st round, October 2018.
Papers in refereed conferences
 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, 1721 September 2018, Moscow, Russia.
 N. Pappas, I. Dimitriou, Z. Chen, (2018). Networklevel 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)
 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, 24 July 2018.
 I. Dimitriou, (2018). Performance modelling of a twouser interferencelimited random access network with collisions. Accepted in the Stochastic Networks Conference 2018, Poster session, Edinburgh, UK, June 2529, 2018.
 I. Dimitriou, (2018). Queueing models with statedependent 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 1315, 2018.
 I. Dimitriou, K. Katsanou, (2018). Stationary analysis of an adaptive twoclass 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 1315, 2018.
 I. Dimitriou, N. Pappas, (2018). Performance Analysis of an Adaptive QueueAware Random Access Scheme with Random Traffic. Accepted for presentation in IEEE ICC 2018 Wireless Networking Symposium (Acceptance rate 39.99%).
 I. Dimitriou, T. PhungDuc, (2018). A RiemannHilbert boundary value problem for singleserver systems with two queues for blocked and feedback customers. AIP Conference Proceedings 1978 (1), 190004 (2018); https://doi.org/10.1063/1.5043831
 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 78 2017.
 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)
 I. Dimitriou, N. Pappas, (2017). Stable Throughput and Delay Analysis of a ChannelAware Adaptive Random Access Wireless Network. Accepted in the 24rd International Conference on Analytical &
Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle, UK.
 I. Dimitriou, (2017). Performance analysis of a relayassisted cooperative cognitive network. Accepted in the 24rd International Conference on Analytical &
Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle, UK.
 I. Dimitriou, (2016). A retrial queue to model a tworelay cooperative wireless system with simultaneous packet reception. Accepted in the 23rd International Conference on Analytical &
Stochastic Modelling Techniques & Applications (ASMTA 2016), Cardiff, Wales, UK.
2426 August 2016.
 I. Dimitriou, (2016). Twoclass 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 31September 2, 2016.
 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, 1820 July 2016.
 I. Dimitriou, (2015). A twoclass 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 .
 I. Dimitriou, S. Alouf, A. JeanMarie, (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.
 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, 2629 May 2015.
 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, 16 June 2015.
 I. Dimitriou, (2014). A retrial queue with twotypes of customers and paired services. Accepted for presentation at the First European Conference on Queueing Theory (ECQT 2014), Ghent, Belgium, 2022 August 2014.
 I. Dimitriou, (2014). A queueing system with probabilistic inhomogeneous vacations for modeling powersaving in wireless systems with retransmissions. Accepted for presentation at the 29th International Symposium on Computer and Information Sciences, Krakow, Poland, October 2728th, 2014.
 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, 2830 June 2012.
 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 May1 June 2012.
 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 1719, 2008.
Other publications
 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 JuneDecember 2009, pp 113.
 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
IEEE Access
IEEE Systems
Journal of Operations Research Society (JORS)
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
PhungDuc, T. and Dimitriou, I., Eds., Proceedings of Symposium on Stochastic Models: Methods and Applications (SAMMA 2016 within the ICNAAM 2016, Rhodes, Greece, 1925 September 2016.), AIP Conference Proceedings, Vol. 1863, 200001, 2017. [DOI: 10.1063/1.4992372]
PhungDuc, T. and Dimitriou, I. and Vatamidou, E. Eds., Proceedings of Symposium on Stochastic Models: Methods and Applications (SAMMA 2017 within the ICNAAM 2017, 2530 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.
CoOrganizer of the 1st Symposium on Stochastic Models: Methods and Applications (SAMMA 2016), 14th International Conference of Numerical Analysis and Applied Mathematics, 1925 September 2016, Rodos Palace Hotel, Rhodes, Greece (with with Dr. Tuan PhungDuc (Tokyo Institute of Technology, Tokyo, Japan)).
Program Committee Member for the 24rd International Conference on Analytical &
Stochastic Modelling Techniques & Applications (ASMTA 2017), Newcastle UK.
CoOrganizer of the 2nd Symposium on Stochastic Models: Methods and Applications (SAMMA 2017), 15th International Conference of Numerical Analysis and Applied Mathematics, 2530 September 2016, The MET Hotel, Thessaloniki, Greece (with with Dr. Tuan PhungDuc (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). Twoclass 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 456, 2013.
I. Dimitriou. (2013). Performance Analysis of the Discontinuous Reception
(DRX) power saving method in 3GPP LTE: A queueing perspective. FORTHInstitute of Computer Science, HerakleionGreece, 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, SophiaAntipolis, France. September 49, 2016. Host: K. Avrachenkov.
TU/e, Stochastics Group, Eindhoven, Netherlands. May 28June 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 1315, 2018.
Marie Curie Fellow, ERCIM Alain
Bensoussan Fellowship Programme, cofunded by the European Commission
under the FP7 MarieCurie action named ABCDE.
Post Doctoral fellowship 'Research Excellence', 1/1/201331/12/2013, 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 (20042005, 20062008).
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 (2015Dept. of Mathematics, Univ. of Patras).
Probability theory and Stochastic processes (2014,Dept. of Material Sciences, Univ. of Patras)
Mathematics I (20142015, Dept. of Geology, Univ. of Patras)
Postgradute courses
Stochastic Processes (MSc program on "Computer and Decision Mathematics", coorganized with
Computer Engineering & Informatics Department), 20142018.
Operations Research (MSc program on "Computer and Decision Mathematics", coorganized with
Computer Engineering & Informatics Department), 20142018.
Queueing Systems (MSc program on "Computer and Decision Mathematics", coorganized with
Computer Engineering & Informatics Department), 20142018.
Datadriven 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 (MSc Thesis, in Greek, Nemertes DSpace).
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 relayassisted networks.
D. Kintos, (2017). Birthdeath 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: October, 18, 2018
