Koutras Vasilis

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Όνομα: 
Vasilis
Επώνυμο: 
Koutras
Βαθμίδα: 
Assistant Professor
Member of Faculty
Area of expertise: 
Stochastic Modeling
Short Curriculum vitae: 

Dr Vasilis Koutras is currently a Lecturer at the Department of Financial and Management Engineering. He holds a Bachelor degree in Mathematics (Probability, Statistics & Operational Research)-(2002) from the Department of Mathematics, University of Patras, a Master degree in Mathematical Modeling in Physical Sciences and new Technologies (2004), from the Department of Mathematics, University of the Aegean. He received his PhD diploma from the Department of Financial and Management Engineering, University of the Aegean. He is a member of the Reliability Engineering Laboratory (REL). He is also Academic Staff at the Hellenic Open University, School of Science & Technology, PostGraduate Programme: Quality Assurance Msc, Course:DIP50 Basic Tools and Methods for Quality Control (Ac. Years 2013-14, 2015-16). He is teaching Operations Research ΙΙ, Modeling Analysis and Design of Stochastic Systems, Statistics, Stochastic Models, Queuing Theory. He has published over 40 papers in international journals, book chapters and international conferences proceedings (with review procedure). He also participates as a Researcher in the European Funding Project: THALES: “Analysis of Supply and Production Systems: an Integrated Approach” (ASPASIA).

Curriculum vitae: 
Μαθήματα που Διδάσκει στο Πρόγραμμα Προπτυχιακών Σπουδών: 
Office: 
A7.2
Address: 
Kountouriotou 41
Telephone: 
2271035468
Ώρες επικοινωνίας: 
Tuesday 15:00-18:00
Wednesday 12:00-15:00
Email: 
v [dot] koutras [at] fme [dot] aegean [dot] gr
Publications: 

Α. International Journals

1.V.P. Koutras, S. Malefaki, A.N. Platis, Optimization of the dependability and performance measures of a generic model for multi-state deteriorating systems under maintenance, Reliability Engineering & System Safety, Available online 4 January 2017, ISSN 0951-8320, doi: http://dx.doi.org/10.1016/j.ress. 201701.002.

2. A. Manatos, V. P. Koutras and A. N. Platis, (2016). Dependability and performance stochastic modelling of a two-unit repairable production system with preventive maintenance, International Journal of Production Research, 54 (21), Pages. 6395-6415.. doi: 10.1080/00207543.2016.1201603

3. C. Salagaras, V. P. Koutras, N.S. Thomaidis, V. Vassiliadis, A.N. Platis, G. Dounias and C. Kyriazis, (2016). Resource Availability Modeling and Optimization in a Car Park Management Problem. International Journal of Operations Research and Information Systems, Special Issue: Operations Research and its Application in Engineering, to appear as IJORIS 8(2), 2017.

4. V. P. Koutras and A. N. Platis, (2016). User-perceived Availability of a Software Rejuvenation Model with Recovery Time Omission. Quality and Reliability Engineering International, Vol. 32, Pages 1521–1533. doi: 10.1002/qre.1862

5. V.P. Koutras, S. Malefaki and A.N. Platis, (2014). Rejuvenation Effects on the Grid Environment Performance with Response Time Delays using Monte Carlo Simulation, Simulation Modelling Practice and Theory, Vol. 40, Pages 176-191. doi: http://dx.doi.org/10.1016/j.simpat.2013.10.001

6. V.P. Koutras, A. N. Platis and G. A. Gravvanis, (2013). Software Rejuvenation and Resource Reservation Policies for Optimizing Server Resource Availability using Cyclic Non-Homogeneous Markov Chains, Applied Stochastic Models in Business and Industry, Vol. 29(1), Pages 61-78. doi: 10.1002/asmb.945.

7. V.P. Koutras and A.N. Platis (2010). Semi-Markov Performance Modeling of a Redundant System with Partial, Full and Failed Rejuvenation, International Journal of Critical Computer Based Systems, Inderscience Publishers, Vol. 1, (1/2/3), Pages 59-85. doi: 10.1504/IJCCBS.2010.031909

8. V.P. Koutras, A.N. Platis and G.A. Gravvanis, (2009). Availability and Performance on a Grid Computing Environment with Software Rejuvenation Based on Approximate Inverse Preconditioning. HERMIS: The International Journal of Computer Mathematics and its Applications, Elias A. Lipitakis (Editor-in-Chief), Vol. 11, Pages 69-86, Published on behalf of the AUEB-RG-ACMPP (ΠΥΜΠΕ) by LEA, Athens, Hellas, ISSN: 1108-7609.

9. V.P. Koutras, A.N. Platis and G.A. Gravvanis, (2009). Optimal Server Resource Reservation Policies for Priority Classes of Users under Cyclic Non-Homogeneous Markov Modeling, European Journal of Operational Research, Vol. 198, Pages 545-556. doi: http://dx.doi.org/10.1016/j.ejor.2008.09.031

10. V.P. Koutras, A.N. Platis and G.A. Gravvanis, (2007). Software Rejuvenation for Resource Optimization Based on Explicit Approximate Inverse Preconditioning, Applied Mathematics and Computation, Vol. 189(1), John L. Casti, Melvin Scott (eds.), Elsevier, Vol. 187(1), Pages 163-177. doi: http://dx.doi.org/10.1016/j.amc.2006.11.056

11. V.P. Koutras, A. N. Platis and G. A. Gravvanis, (2007). On the Optimization of Free Resources Using Non-Homogeneous Markov Chain Software Rejuvenation Model. Reliability Engineering and System Safety, Vol. 92(12), Pages 1724–1732. doi : http://dx.doi.org/10.1016/j.ress.2006.09.017

Β. Book Chapters

1. V.P. Koutras, (2011). Two-Level Software Rejuvenation Model with Increasing Failure Rate Degradation. Dependable Computer Systems, Advances in Intelligent and Soft Computing Vol. 97, Springer-Verlag Berlin Heidelberg, Pages 101-115. doi: 10.1007/978-3-642-21393-9_8

Γ. Proceeding of International Conferences (with review)

1. S. Malefaki, V.P. Koutras and A.N. Platis, (2016). Multi-State Deteriorating System Dependability with Maintenance using Monte Carlo Simulation. In Proc of SMRLO'16 2016:Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management, February 2016, SCE- Shamoon College of Engineering, Beer Sheva, Israel, Pages 61-70. doi: 10.1109/SMRLO.2016.21

2. C.S. Salagaras, V.P. Koutras, A.N. Platis and I.A. Tsokos, (2016). Resource Availability Optimization for a Point-to-Point Connection on a Telecommunication Network. In Proc of SMRLO'16 2016:Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management, February 2016, SCE- Shamoon College of Engineering, Beer Sheva, Israel, Pages 176-185. doi: 10.1109/SMRLO.2016.39

3. T.V. Tzioutzias, A.N. Platis and V.P. Koutras, (2016). Markov Modeling of the Availability of a Wind Turbine Utilizing Failures and Real Weather Data. In Proc of SMRLO'16 2016:Second International Symposium on Stochastic Models in Reliability Engineering, Life Science and Operations Management, February 2016, SCE- Shamoon College of Engineering, Beer Sheva, Israel, Pages 166-196. doi: 10.1109/SMRLO.2016.40

4. I. I. Stamoulis, A. N. Platis and V. P. Koutras (2015). Planning of electric power distribution networks with reliability criteria. Theory and Engineering of Complex Systems and Dependability, Advances in Intelligent Systems and Computing, Online ISBN 978-3-319-19216-1, W. Zamojski et al. (eds), Springer International Publishing, Volume 365, Pages 455-464. doi: 10.1007/978-3-319-19216-1_43

5. P. Diamantopoulos, V.P. Koutras and A.N. Platis, (2014). Cloud computing service reliability modeling with batch arrivals and retrial queues. Safety, Reliability and Risk Analysis: Beyond the Horizon-Steenbergen et al (Eds), 2014 Taylor & Francis Group, London, ISBN 978-1-138-00123-7, Pages 2941-2949. doi:10.1201/b15938-443

6. A.N. Platis, V.P. Koutras and S. Malefaki, (2014). Achieving high availability levels of a deteriorating system by optimizing condition based maintenance policies. Safety, Reliability and Risk Analysis: Beyond the Horizon-Steenbergen et al (Eds), 2014 Taylor & Francis Group, London, ISBN 978-1-138-00123-7, Pages 829-837.

7. S. Malefaki, V.P. Koutras and A.N. Platis, (2014). Optimizing the Availability and the Operational Cost of a Periodically Inspected Multi-state Deteriorating System with Condition Based Maintenance Policies. In Proc of 2014 Ninth International Conference on Availability, Reliability and Security (ARES), Pages 403-411, 8-12 Sept. 2014. doi: 10.1109/ARES.2014.61

8. I.G. Sideratos, A. N. Platis, V. P. Koutras and N. Ampazis, (2014). Reliability analysis of a two-stage Goel-Okumoto and Yamada S-shaped model. In Proc of Ninth International Conference on Dependability and Complex Systems DepCoS-RELCOMEX. June 30 – July 4, 2014, Brunów, Poland, Advances in Intelligent Systems and Computing, Series Vol. 286, pp 393-402. doi: 10.1007/978-3-319-07013-1_38

9. T.V. Tzioutzias, A. N. Platis and V. P. Koutras, (2014). Modeling the Reliability and the Performance of a Wind Farm Using Cyclic Non-Homogenous Markov Chains. In Proc of Probabilistic Safety Assessment & Management conference (PSAM12), June 2014, United States, Honolulu, Hawaii.

10. V.P. Koutras, A.N. Platis and C.S. Salagaras, (2013). Resource Availability Optimization for Green Courier Service. In Proc of 2013 IFAC Conference on Manufacturing Modeling, Management, and Control (MIM 2013), Pages 1654-1659. doi:10.3182/20130619-3-RU-3018.00468

11. N. S. Thomaidis, C.S. Salagaras, V. Vassiliadis, V.P. Koutras, A.N. Platis and G. Dounias, (2013). Evolutionary Algorithms for Solving Resource Availability Optimization Problems related to Client Service of Different Priority Classes. In Proc of 2nd International Symposium and 24th National Conference on Operational Research, ISBN: 978-618-80361-1-6, Athens, Greece, September 26-28, (2013), Pages 252-257.

12. S. Malefaki, V.P. Koutras and A.N. Platis, (2012). Modeling Software Rejuvenation on a Redundant System Using Monte Carlo Simulation. In Proc of 2012 IEEE 23rd International Symposium on Software Reliability Engineering Workshops (ISSREW), Dallas TX, USA, Pages 277-282. doi: 10.1109/ISSREW.2012.89.

13. V.P. Koutras, A.N. Platis and N. Limnios, (2012). Performance Estimation of a System under Minimal, Perfect and Failed Rejuvenation. In Proc of 11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012 (PSAM11 & ESREL12), Vol. 3, Pages: 1859-1868.

14. V.P. Koutras and A.N. Platis, (2011). Applying Partial and Full Rejuvenation in Different Degradation Levels. In Proc of 22nd annual International Symposium on Software Reliability Engineering (ISSRE 2010)-3rd Workshop on Software Aging and Rejuvenation (WoSAR 2011), Hiroshima, Japan, Pages 20-25. doi: 10.1109/WoSAR.2011.14

15. V.P. Koutras, S. Malefaki and A.N. Platis, (2011). A Monte Carlo Simulation Based Dependability Analysis of a non-Markovian Grid Computing Environment with Software Rejuvenation. Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011, Pages: 1959-1966. doi: 10.1201/b11433-276.

16. E.C. Grigoriadou, V.P. Koutras, A.N. Platis, (2011). Semi-Markov coverage modeling and optimal maintenance policies of an automated restoration mechanism. Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011, Pages: 949-956. doi: 10.1201/b11433-133.

17. A.N. Platis and V.P. Koutras, (2010). Software Rejuvenation on a PKI Infrastructure. In Proc of 21st annual International Symposium on Software Reliability Engineering (ISSRE 2010)-2nd Workshop on Software Aging and Rejuvenation (WoSAR 2010), San Jose, USA, Pages 1-6. doi:: 10.1109/WOSAR.2010.5722102.

18. V.P. Koutras, A.N. Platis and N. Limnios, (2010). Dependability Measures Maximum Likelihood Estimation for a Redundant System with Minimal. Perfect and Failed Rejuvenation, In Proc of European Safety and Reliability Conference, ESREL 2010, Pages. 1553-1560.

19. V.P. Koutras, C.S. Salagaras and A.N. Platis, (2009). Software Rejuvenation for Higher Levels of VoIP Availability and Mean Time To Failure. In Proc of 4th International Conference on Dependability of Computer Systems (DepCoS-RELCOMEX '09), © 2009, IEEE Computer Society Press, Pages 99-106. doi: http://doi.ieeecomputersociety.org/10.1109/DepCoS-RELCOMEX.2009.21.

20. V.P. Koutras and A.N. Platis, (2009). Modeling Resource Availability and Optimal Fee for Priority Classes in a Website. In Proc of European Safety and Reliability Conference (ESREL 2009), Pages 1191-1198.

21. J.B. Violentis, A.N. Platis, G.A. Gravvanis and V.P. Koutras, (2009). Electrical Substation Efficient Maintenance Policies Based On Semi-Markov Modeling and Approximate Inverse Preconditioning. In Proc of 9th Hellenic European Research on Computer Mathematics & its Applications Conference (HERCMA 2009).

22. P.K. Saravakos, G.A. Gravvanis, V.P. Koutras and A.N. Platis, (2009). A Comprehensive Approach to Software Aging and Rejuvenation on a Single Node Software System. In Proc of 9th Hellenic European Research on Computer Mathematics & its Applications Conference (HERCMA 2009).

23. V.P. Koutras, A.N. Platis and N. Limnios, (2008). Availability and Reliability Estimation for a System Undergoing Minimal, Perfect and Failed Rejuvenation. In Proc of First International Workshop on Software Aging and Rejuvenation WOSAR 2008 in conjunction with 19th IEEE International Symposium on Software Reliability Engineering ISSRE 2008, IEEE Xplorer, Pages 1-6. doi: 10.1109/ISSREW.2008.5355519.

24. V.P. Koutras and A.N. Platis (2008). Guaranteed Resource Availability in a Website, Safety, Reliability and Risk Analysis: Theory, Methods and Applications – Martorell et al. (eds), Taylor & Francis Group, London, Pages 1525-1532.

25. V.P. Koutras and A.N. Platis, (2008). Modeling Perfect and Minimal Rejuvenation for Client Server Systems with Heterogeneous Load. In Proc of 14th IEEE Pacific Rim International Symposium on Dependable Computing, IEEE Computer Society Press, Pages 95-103. doi: 10.1109/PRDC.2008.22.

26. V.P. Koutras and A.N. Platis, (2008). Semi-Markov Availability Modeling of a Redundant System with Partial and Full Rejuvenation Actions. In Proc of 3rd International Conference on Dependability of Computer Systems (DepCoS-RELCOMEX '08), © 2008, IEEE Computer Society Press, Pages 127-134. doi: 10.1109/DepCoS-RELCOMEX.2008.13 .

27. V.P. Koutras, A.N. Platis and G. A. Gravvanis, (2007). Software Rejuvenation on a Grid Computing Environment for Higher Availability Based on Approximate Inverse Preconditioning. In Proc of 8th Hellenic European Research on Computer Mathematics & its Applications Conference (HERCMA 2007).

28. J.B. Violentis, V.P. Koutras, A.N. Platis and G.A. Gravvanis, (2007). Asymptotic Availability of an Electrical Substation via a Semi-Markov Process Computed by Generalized Approximate Inverse Preconditioning. In Proc of 8th Hellenic European Research on Computer Mathematics & its Applications Conference (HERCMA 2007).

29. V.P. Koutras and A.N. Platis, (2007). VoIP Availability and Service Reliability through Software Rejuvenation Policies. In Proc of 2nd International Conference on Dependability of Computer Systems (DepCoS-RELCOMEX '07), IEEE Computer Society Press, Pages 262-269. doi: 10.1109/DEPCOS-RELCOMEX.2007.54 .

30. V.P. Koutras, A.N. Platis and G. A. Gravvanis, (2007). Software Rejuvenation for Higher Levels of Grid Availability. Risk, Reliability and Societal Safety – Aven & Vinnem (eds), © 2007 Taylor & Francis Group, London, Pages 1723-1730.

31. V.P. Koutras and A.N. Platis, (2006). Resource Availability Optimization for Priority Classes in a Website. In Proc of 12th IEEE International Symposium on Pacific Rim Dependable Computing(PRDC ’06), Jeske, Giardo, Dai (eds)© 2006, IEEE Computer Society Press, Los Alamitos, California, Pages 305-312. doi: 10.1109/PRDC.2006.54 .

32. V.P. Koutras and A.N. Platis, (2006). Applying software rejuvenation in a two node cluster system for high availability. In Proc of International Conference on Dependability of Computer Systems (DEPCOS-RELCOMEX'06), IEEE Computer Society Press, Pages 175-182. doi: 10.1109/DEPCOS-RELCOMEX.2006.7.

33. V.P. Koutras and A.N. Platis, (2006). Optimal Rejuvenation Policy for Increasing VoIP Service Reliability, Advances in Safety and Reliability, Soares (ed.), Taylor & Francis Group, London, Vol. 3, Pages 2285-2290.

34. V.P. Koutras and A. Platis, (2005). Optimizing the Amount of Free Resources on a Computer System using Software Rejuvenation, Advances in Safety and Reliability, Kołowrocki (ed.), Taylor & Francis Group, London, Pages 1187-1192.

35. V.P. Koutras, E. Mennis, N. Nikitakos and A.N. Platis, (2005). Software rejuvenation in maritime applications, Advances in Safety and Reliability Kołowrocki (ed.)© 2005 Taylor & Francis Group, London, Pages 1193-1197.

Δ. Anouncements in National and International Conferences

1. A. Μανάτος, Σ. Μαλεφάκη και Β. Κούτρας, (2016).. Μοντελοποίηση και Βελτιστοποίηση Μέτρων Διαθεσιμότητας και Απόδοσης Συστημάτων με Πολλαπλά Σταδία Υποβάθμισης και Εφεδρεία, 29o Πανελλήνιο Συνέδριο Στατιστικής, (2016).

2. Σ. Μαλεφάκη, Β. Κούτρας και Α. Πλατής, (2015). Βελτιστοποίηση πολιτικών συντήρησης τεχνολογικών συστημάτων, 28ο Πανελλήνιο Συνέδριο Στατιστικής, (2015).

3. V. Vassiliadis, C. Salagaras, V. Koutras, N. Thomaidis, A. Platis, G. Dounias and C. Kyriazis, (2014). Resource availability modeling and optimization in a car park management problem, 3rd International Symposium & 25th National Conference on Operational Research, Volos, Greece, 26-28 June 2014.

4. V.P. Koutras, S. Malefaki and A. N. Platis, (2011). Dependability Analysis of a Software Rejuvenation Model Based on Monte Carlo Simulation, 24ο Πανελλήνιο Συνέδριο Στατιστικής, (2011).

 

Ερευνητικά ενδιαφέροντα: 

Stochastic modeling of highly available and reliable systems. Stochastic modeling of software rejuvenation, computer systems performability indicators, Markov and Semi-Markov processes, operations research.

Doctoral
Θέμα: 
Optimizing Performance and Dependability of Computer Systems: Software Rejuvenation Stochastic Modeling
Επιβλέπων: 
Year of completion: 
2010