Hiroyuki Okamura

Last Updated :2022/08/02

Affiliations, Positions
Graduate School of Advanced Science and Engineering, Professor
E-mail
okamuhiroshima-u.ac.jp
Self-introduction
Reliability Engineering, Software Reliability, Stochastic Model

Basic Information

Major Professional Backgrounds

  • 2007/04/01, 2010/03/31, Hiroshima University, Graduate School of Engineering, Associate Professor
  • 2003/04/01, 2018/03/31, Hiroshima University, Graduate School of Engineering, Associate Professor
  • 2003/04/01, 2007/03/31, Hiroshima University, Graduate School of Engineering, Assistant Professor
  • 2001/04/01, 2003/03/31, Hiroshima University, Graduate School of Engineering, Assistant
  • 1998/10/01, 2001/03/31, Hiroshima University, School of Engineering, Assistant
  • 1997/04/01, 1998/09/30, CSK Corporation, Regular Employee
  • 2018/04/01, 2020/03/31, Hiroshima University, Graduate School of Engineering, Professor

Educational Backgrounds

  • Hiroshima University, Faculty of Engineering, Japan, 1991/04, 1995/03
  • Hiroshima University, Graduate School, Division of Engineering, Japan, 1995/04, 1997/03

Academic Degrees

  • Doctor of Engineering, Hiroshima University
  • Master of Engineering, Hiroshima University

Research Fields

  • Informatics;Principles of Informatics;Mathematical informatics
  • Complex systems;Social / Safety system science;Social systems engineering / Safety system

Research Keywords

  • Stochastic Model
  • Performance Analysis
  • Reliability Engineering
  • Software Reliability Engineering
  • Operations Research

Affiliated Academic Societies

Educational Activity

Course in Charge

  1. 2022, Undergraduate Education, Intensive, Basics of Data Engineering
  2. 2022, Undergraduate Education, 4Term, Numerical Computation
  3. 2022, Undergraduate Education, 2Term, Software Engineering
  4. 2022, Undergraduate Education, 2Term, Software Management
  5. 2022, Undergraduate Education, Intensive, Data Analysis for Medical and Welfare Policies
  6. 2022, Graduate Education (Master's Program) , 1Term, Special Exercises on Informatics and Data Science A
  7. 2022, Graduate Education (Master's Program) , 2Term, Special Exercises on Informatics and Data Science A
  8. 2022, Graduate Education (Master's Program) , 3Term, Special Exercises on Informatics and Data Science B
  9. 2022, Graduate Education (Master's Program) , 4Term, Special Exercises on Informatics and Data Science B
  10. 2022, Graduate Education (Master's Program) , Academic Year, Special Study on Informatics and Data Science
  11. 2022, Graduate Education (Doctoral Program) , Academic Year, Special Study on Informatics and Data Science

Research Activities

Academic Papers

  1. Optimal control of preventive maintenance schedule and safety stocks in an unreliable manufacturing environment, INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS, 74(1-3), 147-155, 20011201
    Link to Paper Search Results by DOI
  2. A structural approximation method to generate the optimal auto-sleep schedule for computer systems, COMPUTERS & MATHEMATICS WITH APPLICATIONS, 46(7), 1103-1110, 200310
    Link to Paper Search Results by DOI
  3. Phase type approximation for optimal auto-sleep scheduling, MATHEMATICAL AND COMPUTER MODELLING, 38(11-13), 1391-1398, 200312
    Link to Paper Search Results by DOI
  4. Rejuvenating communication network system under burst arrival circumstances, IEICE TRANSACTIONS ON COMMUNICATIONS, E88B(12), 4498-4506, 200512
    Link to Paper Search Results by DOI
  5. Distribution-free checkpoint placement algorithms based on min-max principle, IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING, 3(2), 130-140, 2006
    Link to Paper Search Results by DOI
  6. Discrete-time cost analysis for a telecommunication billing application with rejuvenation, COMPUTERS & MATHEMATICS WITH APPLICATIONS, 51(2), 335-344, 200601
    Link to Paper Search Results by DOI
  7. Gompertz software reliability model: Estimation algorithm and empirical validation, JOURNAL OF SYSTEMS AND SOFTWARE, 82(3), 535-543, 200903
    Link to Paper Search Results by DOI
  8. Software Reliability Modeling Based on Capture-Recapture Sampling, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E92A(7), 1615-1622, 200907
    Link to Paper Search Results by DOI
  9. Markovian Arrival Process Parameter Estimation With Group Data, IEEE-ACM TRANSACTIONS ON NETWORKING, 17(4), 1326-1339, 200908
    Link to Paper Search Results by DOI
  10. A Variational Bayesian Approach for Estimating Parameters of a Mixture of Erlang Distribution, COMMUNICATIONS IN STATISTICS-THEORY AND METHODS, 39(13), 2333-2350, 2010
    Link to Paper Search Results by DOI
  11. Comprehensive evaluation of aperiodic checkpointing and rejuvenation schemes in operational software system, JOURNAL OF SYSTEMS AND SOFTWARE, 83(9), 1591-1604, 201009
    Link to Paper Search Results by DOI
  12. A refined EM algorithm for PH distributions, PERFORMANCE EVALUATION, 68(10), 938-954, 201110
    Link to Paper Search Results by DOI
  13. Software Reliability Prediction Based on Least Squares Estimation, QUALITY TECHNOLOGY AND QUANTITATIVE MANAGEMENT, 9(3), 243-264, 201209
    Link to Paper Search Results by DOI
  14. Application of Markov Chain Monte Carlo Random Testing to Test Case Prioritization in Regression Testing, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E95D(9), 2219-2226, 201209
    Link to Paper Search Results by DOI
  15. Enhancing Performance of Random Testing through Markov Chain Monte Carlo Methods, IEEE TRANSACTIONS ON COMPUTERS, 62(1), 186-192, 201301
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  16. Dynamic software rejuvenation policies in a transaction-based system under Markovian arrival processes, PERFORMANCE EVALUATION, 70(3), 197-211, 201303
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  17. Improvement of expectationmaximization algorithm for phase-type distributions with grouped and truncated data, APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, 29(2), 141-156, 2013
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  18. Performance evaluation of workload-based software rejuvenation scheme, IEICE Transactions on Information and Systems, E84D(10), 1368-1375, 20011001
  19. Discrete availability models to rejuvenate a telecommunication billing application, IEICETRANSACTIONSONCOMMUNICATIONS, E86B(10), 2931-2939, 20031001
  20. Fine-Grained Shock Models to Rejuvenate Software Systems, IEICE Transactions on Information and Systems, E86D(10), 2165-2171, 20031001
  21. Performance evaluation of power-aware communication network devices, EMBEDDEDANDUBIQUITOUSCOMPUTING-EUC2005, 3824, 245-254, 20050101
  22. Cost-effective analysis of software systems with periodic rejuvenation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E85A(12), 2923-2932, 20021201
  23. Dependability Analysis of a Transaction-Based Multi-Server System with Rejuvenation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E86A(8), 2081-2090, 20030801
  24. Optimal policies for a controlled queueing system with removable server under a random vacation circumstance, COMPUTERS & MATHEMATICS WITH APPLICATIONS, 39(1-2), 215-227, 200001
    Link to Paper Search Results by DOI
  25. Performance evaluation of workload-based software rejuvenation scheme, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E84D(10), 1368-1375, 200110
    Link to Paper Search Results by DOI
  26. Cost-effective analysis of software systems with periodic rejuvenation, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E85A(12), 2923-2932, 200212
    Link to Paper Search Results by DOI
  27. Dependability analysis of a transaction-based multi-server system with rejuvenation, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E86A(8), 2081-2090, 200308
    Link to Paper Search Results by DOI
  28. Discrete availability models to rejuvenate a telecommunication billing application, IEICE TRANSACTIONS ON COMMUNICATIONS, E86B(10), 2931-2939, 200310
    Link to Paper Search Results by DOI
  29. Fine-grained shock models to rejuvenate software systems, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E86D(10), 2165-2171, 200310
    Link to Paper Search Results by DOI
  30. Performance evaluation of power-aware communication network devices, EMBEDDED AND UBIQUITOUS COMPUTING - EUC 2005, 3824, 245-254, 2005
    Link to Paper Search Results by DOI
  31. NHPP-Based Software Reliability Models Using Equilibrium Distribution, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, E95A(5), 894-902, 201205
    Link to Paper Search Results by DOI
  32. Software reliability growth models with normal failure time distributions, RELIABILITY ENGINEERING & SYSTEM SAFETY, 116, 135-141, 201308
    Link to Paper Search Results by DOI
  33. Optimal Trigger Time of Software Rejuvenation under Probabilistic Opportunities, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E96D(9), 1933-1940, 201309
    Link to Paper Search Results by DOI
  34. Application of deterministic annealing EM algorithm to MAP/PH parameter estimation, TELECOMMUNICATION SYSTEMS, 54(1), 79-90, 201309
    Link to Paper Search Results by DOI
  35. Variational Bayes for Phase-Type Distribution, COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION, 43(8), 2031-2044, 20140914
    Link to Paper Search Results by DOI
  36. Transient Analysis of Software Rejuvenation Policies in Virtualized System: Phase-Type Expansion Approach, QUALITY TECHNOLOGY AND QUANTITATIVE MANAGEMENT, 11(3), 335-351, 201409
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  37. Performance evaluation of snapshot isolation in distributed database system under failure-prone environment, JOURNAL OF SUPERCOMPUTING, 70(3), 1156-1179, 201412
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  38. A Fast EM Algorithm for Fitting Marked Markovian Arrival Processes with a New Special Structure, Proceedings of 10th European Workshop on Performance Engineering (EPEW 2013), 119-133, 2013
  39. Aperiodic checkpoint placement algorithms -- survey and comparison --, Journal of Software Engineering and Applications, 6(4A), 41-53, 2013
  40. Estimating response time distribution of server application in software aging phenomenon,, Proceedings of IEEE 5th International Workshop on Software Aging and Rejuvenation (WoSAR-2013), 4, 2013
  41. Estimating software reliability with static project data in incremental development processes, Proceedings of 2013 Joint Conference of the 23rd International Workshop on Software Measurement (IWSM-2013) and the 8th International Conference on Software Process and Product Measurement (MENSURA-2013), 219-224, 2013
  42. Generalized Cox proportional hazards regression-based software reliability modeling with metrics data, Proceedings of The 19th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2013),, 328-337, 2013
  43. Modeling and analysis of multi-version concurrent control,, Proceedings of The 37th Annual International Computer Software and Applications Conference (COMPSAC 2013), 53-58, 2013
  44. NHPP-based software reliability model with mixed gamma distribution,, Advanced Science and Technology Letters, 19, 240-243, 2013
  45. Quantifying software test process and product reliability simultaneously,, Proceedings of The 24th International Symposium on Software Reliability Engineering (ISSRE 2013), 108-117, 2013
  46. Quantitative security evaluation for software system from vulnerability database, Journal of Software Engineering and Applications, 6(4A), 15-23, 2013
  47. Semi-parametric approach for software reliability evaluation using mixed gamma distributions, International Journal of Software Engineering and Its Applications, 7(4), 401-414, 2013
  48. Sensitivity analysis of reliability function for virtualized system,, Proceedings of the 8th International Conference on Mathematical Methods in Reliability, --Theory, Methods and Applications -- (MMR-2013), 229-232, 2013
  49. SRATS: Software reliability assessment tool on spreadsheet, Proceedings of The 24th International Symposium on Software Reliability Engineering (ISSRE 2013),, 100-117, 2013
  50. A novel framework of software reliability evaluation with software reliability growth models and software metrics, Proceedings of The 15th IEEE International Symposium on High Assurance Systems Engineering (HASE 2014), 97-104, 20140109
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  51. Quantifying resiliency of virtualized system with software rejuvenation, Proceedings of The 2014 International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering (QR2MSE 2014), 6 pages, 20140723
  52. Optimized patch applying schedule within multiplex software architecture, Proceedings of The 6th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2014), 311-318, 20140821
  53. Fine-grained software reliability estimation using software testing inputs, Proceedings of The 6th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2014), 365-372, 20140821
  54. Maximum penalized likelihood estimation for phase-type software reliability growth model, Proceedings of The 6th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2014), 373-380, 20140821
  55. Optimal reliability design for real-time systems with dynamic voltage and frequency scaling, Proceedings of The 20th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2014), 213-222, 20141118
  56. Coarse-grained parallel uniformization for continuous-time Markov chains, Proceedings of The 20th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2014), 116-124, 20141118
  57. Availability importance measures for virtualized system with live migration, Applied Mathematics, 6, 359-372, 20150201
  58. Network survivability modeling and analysis for power-aware MANETs by Markov regenerative processes, Telecommunication Systems Journal, 60, 471-484, 20150317
  59. Quantifying resiliency of virtualized system with software rejuvenation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (A), E98-A(10), 2051-2059, 20151001
  60. Survivability analysis of VM-based intrusion tolerant systems, IEICE Transactions on Information and Systems (D), E98-D(12), 2082-2090, 20151201
  61. A Markov decision process approach to dynamic power management in a cluster system, IEEE Access, 3(1), 1-9, 20151217
  62. PH fitting algorithm and its application to reliability engineering, Journal of the Operations Research Society of Japan, 59(1), 72-109, 20160202
  63. Optimal planning for open source software updates, Proceedings of the Institution of Mechanical Engineerings, Part O: Journal of Risk and Reliability, 230(1), 44-53, 20160111
  64. Analysis of optimal restart policies for software systems, Journal of Japan Industrial Management Association, 66(4E), 416-425, 20160305
  65. A note on variational Bayes approach for software reliability growth model with normal distribution, Proceedings of the 9th International Conference on Mathematical Methods in Reliability, Theory, Methods and Applications (MMR-2015), 41-48, 20150601
  66. A note on optimal allocation of testing-resources with architecture-based software reliability model, Proceedings of 2015 International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering (QR2MSE 2015), 1, 8-13, 20150721
  67. Fine-grained software reliability estimation using software testing inputs, Proceedings of 2015 IEEE International Conference on Software Quality, Reliability and Security (QRS 2015), 85-92, 20150803
  68. Optimal power-aware design in a cluster system: Markov decision process approach, Proceedings of the 12th IEEE International Conference on Advanced and Trusted Computing (ATC 2015), 527-532, 20150810
  69. mapfit: An R-based tool for PH/MAP parameter estimation, The 14th International Conference on Quantitative Evaluation of Systems (QEST2015), Lecture Notes in Computer Science, 9295, 105-112, 20150901
  70. Towards comprehensive software reliability evaluation in open source software, Proceedings of the 24th International Symposium on Software Reliability Engineering (ISSRE 2015), 121-129, 20151102
  71. Survivability quantification of wireless ad hoc network taking account of border effects, Proceedings of the 21st IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2015), 149-158, 20151118
  72. Component importance measures for real-time computing systems in the presence of common-cause failures, Proceedings of the 21st IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2015), 301-310, 20151118
  73. Phase-type software reliability model: parameter estimation algorithms with grouped data, ANNALS OF OPERATIONS RESEARCH, 244(1), 177-208, 201609
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  74. Dynamic software availability model with rejuvenation, Journal of the Operations Research Society of Japan, 59(4), 270-290, 20161031
  75. Optimistic and pessimistic maintenance policies, Proceedings of the 2nd International Conference on Mathematical Techniques in Engineering Applications (ICMTEA 2016), 20160429
  76. Mean Time to Security Failure of VM-Based Intrusion Tolerant Systems, Proceedings of the 15th International Workshop on Assurance in Distributed Systems and Networks (ADSN2016), 20160627
  77. Failure-correlated opportunity-based age replacement policies, Proceedings of the 7th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2016), 73-80, 20160824
  78. Performance comparison of algorithms for computing parametric sensitivity functions in continuous-time Markov chains, Proceedings of the 7th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2016), 415-422, 20160824
  79. Markov-based component importance analysis of real-time computing systems in a warm standby configuration, Proceedings of the 7th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2016), 613-620, 20160824
  80. Performance evaluation of VM-Based intrusion tolerant systems with Poisson arrivals, Proceedings of the 4th International Symposium on Computing and Networking (CANDAR 2016), 20161122
  81. A phase expansion approach for transient analysis of software rejuvenation model, Proceedings of the 8th International Workshop on Software Aging and Rejuvenation (WoSAR 2016), 20161023
  82. Dynamic Power Management With Optimal Time-Out Policies, IEEE SYSTEMS JOURNAL, 11(2), 962-972, 201706
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  83. A Comprehensive Evaluation of Software Rejuvenation Policies for Transaction Systems With Markovian Arrivals, IEEE TRANSACTIONS ON RELIABILITY, 66(4), 1157-1177, 201712
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  84. Moment-based approach for some age-based replacement problems, JOURNAL OF INDUSTRIAL AND PRODUCTION ENGINEERING, 34(8), 558-567, 2017
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  85. Component Importance Analysis of Mobile Cloud Computing Systemin the Presence of Common-Cause Failures, IEEE ACCESS, 6, 18630-18642, 2018
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  86. Reliability importance of components in a real-time computing system with standby redundancy schemes, International Journal of Mathematical, Engineering and Management Sciences, 3(2), 64-89, 201806
  87. A pull-type security patch management of an intrusion tolerant system under a periodic vulnerability checking strategy, Proceedings of 42nd IEEE International Conference on Computers, Software and Applications, 201807
  88. A comprehensive evaluation of software reliability modeling based on Marshall-Olkin type fault-detection time distributions, Proceedings of the 24th Asia-Pacific Software Engineering Conference (APSEC 2017), 486-494, 201712
  89. Software reliability modeling and analysis via kernel-based approach, Proceedings of the 22nd International Conference on Engineering of Complex Computer Systems (ICECCS 2017), 154-157, 201711
  90. A generalized bivariate modeling framework of fault detection and correction processes, Proceedings of the 26th International Symposium on Software Reliability Engineering (ISSRE 2017), 35-45, 201710
  91. A statistical framework on software aging modeling with continuous-time hidden Markov model, Proceedings of the 36th International Symposium on Reliable Distributed Systems (SRDS 2017), 114-123, 201709
  92. A note on computation of quasi-stationary distribution in continuous-time Markov chains, Proceedings of the 10th International Conference on Mathematical Methods in Reliability, Theory, Methods and Applications (MMR-2017), 201707
  93. Optimizing Testing-Resource Allocation Using Architecture-Based Software Reliability Model, JOURNAL OF OPTIMIZATION, 2018
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  94. Optimal periodic software rejuvenation policies based on interval reliability criteria, RELIABILITY ENGINEERING & SYSTEM SAFETY, 180, 463-475, 201812
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  95. Parameter Estimation of M-t/M/1/K Queueing Systems With Utilization Data, IEEE ACCESS, 7, 42664-42671, 2019
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  96. Optimal security patch application timing for an intrusion tolerant system, Proceedings of 8th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling, vol. II, 855-859, 2018
  97. A note on availability importance measures of components in smart grid, Proceedings of 8th Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling, vol. I, 75-79, 2018
  98. Parametric Uncertainty Propagation through Dependability Models, Proceedings of Latin-American Symposium on Dependable Computing, 10-18, 2018
  99. Software Test-Run Reliability Modeling with Non-homogeneous Binomial Processes, Proceedings of 23rd IEEE Pacific Rim International Symposium on Dependable Computing, 145-154, 2018
  100. Gompertz software reliability model: Estimation algorithm and empirical validation, JOURNAL OF SYSTEMS AND SOFTWARE, 82(3), 535-543, 2009
  101. Comprehensive evaluation of aperiodic checkpointing and rejuvenation schemes in operational software system, JOURNAL OF SYSTEMS AND SOFTWARE, 83(9), 1591-1604, 2010
  102. Software Reliability Prediction Based on Least Squares Estimation, QUALITY TECHNOLOGY AND QUANTITATIVE MANAGEMENT, 9(3), 243-264, 2012
  103. Application of Markov Chain Monte Carlo Random Testing to Test Case Prioritization in Regression Testing, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E95D(9), 2219-2226, 2012
  104. Dynamic software rejuvenation policies in a transaction-based system under Markovian arrival processes, PERFORMANCE EVALUATION, 70(3), 197-211, 2013
  105. Optimal Trigger Time of Software Rejuvenation under Probabilistic Opportunities, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E96D(9), 1933-1940, 2013
  106. Generalized-Gamma Software Reliability Model, Technical report of IEICE. SS, 103(318), 9-14, 20030912

Publications such as books

  1. 2016/04/14, Principles of Performance and Reliability Modeling and Evaluation, Fitting phase-type distributions and Markovian arrival processes: Algorithms and tools, Springer, 2016, 4, Scholarly Book, Joint work, 英語, H. Okamura and T. Dohi, 49-75, Chapter 3
  2. 2016/12, Advances in Reliability and System Engineering, Connectivity-based survivability analysis with border effects for wireless ad hoc network, Springer, 2016, 12, Scholarly Book, Joint work, 英語, Z. Yi, T. Dohi and H. Okamura, 53-86
  3. 2017/05, Mathematics Applied to Engineering, Quantitative security evaluation of an intrusion tolerant system, Elsevier, 2017, 5, Scholarly Book, Joint work, H. Okamura, T. Dohi, 21-54
  4. 2017/08, Reliability Modeling with Applications, Confidence intervals in optimal checkpoint placement, World Scientific, 2017, 8, Scholarly Book, Joint work, S. Tokumoto, T. Dohi, H. Okamura, W. Y. Yun, 79-99

Awards

  1. 2004/02, "The IEEE Reliability Society Japan Chapter, Outstanding Young Scientist Award", IEEE Reliability Society Japan Chapter