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Mohaqeqi, Morteza
Publications (10 of 13) Show all publications
Mohaqeqi, M., Nasri, M., Xu, Y., Cervin, A. & Årzén, K.-E. (2018). Optimal harmonic period assignment: complexity results and approximation algorithms. Real-time systems, 54(4), 830-860
Open this publication in new window or tab >>Optimal harmonic period assignment: complexity results and approximation algorithms
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2018 (English)In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 54, no 4, p. 830-860Article in journal, Editorial material (Refereed) Published
Abstract [en]

Harmonic periods have wide applicability in industrial real-time systems. Rate monotonic (RM) is able to schedule task sets with harmonic periods up to 100% utilization. Also, if there is no release jitter and execution time variation, RM and EDF generate the same schedule for each instance of a task. As a result, all instances of a task are interfered by the same amount of workload. This property decreases the jitters that happen during sampling and actuation of the tasks, and hence, it increases the quality of service in control systems. In this paper, we consider the problem of optimal period assignment where the periods are constrained to be harmonic and the task set is required to be feasible. We study two variants of this problem. In the first one, the objective is to maximize the system utilization, while in the second one, the goal is to minimize the total weighted sum of the periods. First, we assume that an interval is determined a priori for each task from which its period can be selected. We show that both variants of the problem are (at least) weakly NP-hard. This is shown by reducing the NP-complete number partitioning problem to the mentioned harmonic period assignment problems. Afterwards, we consider a variant of the second problem in which the periods are not restricted to a special interval. We present two approximation algorithms with polynomial-time complexity for this problem and show that the maximum relative error of these algorithms is bounded by a factor of 1.125. Our evaluations show that, on the average, results of the approximation algorithms are very close to an optimal solution.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Harmonic tasks, Period assignment, Real-time schedulability, Hard real-time
National Category
Embedded Systems
Identifiers
urn:nbn:se:uu:diva-368140 (URN)10.1007/s11241-018-9304-0 (DOI)000447408200003 ()
Available from: 2018-12-04 Created: 2018-12-04 Last updated: 2018-12-14Bibliographically approved
Abdullah, J., Dai, G., Mohaqeqi, M. & Yi, W. (2018). Schedulability Analysis and Software Synthesis for Graph-Based Task Models with Resource Sharing. In: Proc. 24th Real-Time and Embedded Technology and Applications Symposium: . Paper presented at RTAS 2018, April 11–13, Porto, Portugal (pp. 261-270). IEEE Computer Society
Open this publication in new window or tab >>Schedulability Analysis and Software Synthesis for Graph-Based Task Models with Resource Sharing
2018 (English)In: Proc. 24th Real-Time and Embedded Technology and Applications Symposium, IEEE Computer Society, 2018, p. 261-270Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
IEEE Computer Society, 2018
National Category
Computer Systems
Identifiers
urn:nbn:se:uu:diva-364848 (URN)10.1109/RTAS.2018.00034 (DOI)000443421100028 ()978-1-5386-5295-4 (ISBN)
Conference
RTAS 2018, April 11–13, Porto, Portugal
Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-12Bibliographically approved
Araujo, H., Carvalho, G., Mohaqeqi, M., Mousavi, M. R. & Sampaio, A. (2018). Sound conformance testing for cyber-physical systems: Theory and implementation. Science of Computer Programming, 162, 35-54
Open this publication in new window or tab >>Sound conformance testing for cyber-physical systems: Theory and implementation
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2018 (English)In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 162, p. 35-54Article in journal (Refereed) Published
Abstract [en]

Conformance testing is a formal and structured approach to verifying system correctness. We propose a conformance testing algorithm for cyber-physical systems, based on the notion of hybrid conformance by Abbas and Fainekos. We show how the dynamics of system specification and the sampling rate play an essential role in making sound verdicts. We specify and prove error bounds that lead to sound test-suites for a given specification and a given sampling rate. We use reachability analysis to find such bounds and implement the proposed approach using the CORA toolbox in Matlab. We apply the implemented approach on a case study from the automotive domain.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Cyber-physical systems, Model-based testing, Conformance testing, Soundness, Reachability analysis
National Category
Computer Sciences Software Engineering
Identifiers
urn:nbn:se:uu:diva-358256 (URN)10.1016/j.scico.2017.07.002 (DOI)000435053400003 ()
Funder
Swedish Research Council, 621-2014-5057
Available from: 2018-08-27 Created: 2018-08-27 Last updated: 2018-08-27Bibliographically approved
Mohaqeqi, M., Abdullah, J. & Yi, W. (2017). An executable semantics for synchronous task graphs: From SDRT to Ada. In: Reliable Software Technologies — Ada-Europe 2017: . Paper presented at 22nd Ada-Europe International Conference on Reliable Software Technologies (Ada-Europe)2017, June 12–16, Vienna, Austria. (pp. 137-152). Springer, 10300
Open this publication in new window or tab >>An executable semantics for synchronous task graphs: From SDRT to Ada
2017 (English)In: Reliable Software Technologies — Ada-Europe 2017, Springer, 2017, Vol. 10300, p. 137-152Conference paper, Published paper (Refereed)
Abstract [en]

We study a graph-based real-time task model in which inter-task synchronization can be specified through a rendezvous mechanism. Previously, efficient methods have been proposed for timing analysis of the corresponding task sets. In this paper, we first formally specify an operational semantics for the model. Next, we describe a method for Ada code generation for a set of such task graphs. We also specify extensions of the approach to cover a notion of broadcasting, as well as global inter-release separation time of real-time jobs. We have implemented the proposed method in a graphical tool which facilitates a model-based design and implementation of real-time software.

Place, publisher, year, edition, pages
Springer, 2017
Series
Lecture Notes in Computer Science ; 10300
National Category
Embedded Systems
Identifiers
urn:nbn:se:uu:diva-326691 (URN)10.1007/978-3-319-60588-3_9 (DOI)000433224100009 ()978-3-319-60587-6 (ISBN)
Conference
22nd Ada-Europe International Conference on Reliable Software Technologies (Ada-Europe)2017, June 12–16, Vienna, Austria.
Projects
UPMARC
Available from: 2017-05-30 Created: 2017-07-22 Last updated: 2018-09-25Bibliographically approved
Mohaqeqi, M., Abdullah, J., Ekberg, P. & Yi, W. (2017). Refinement of workload models for engine controllers by state space partitioning. In: 29th Euromicro Conference on Real-Time Systems: ECRTS 2017. Paper presented at ECRTS 2017, June 27–30, Dubrovnik, Croatia (pp. 11:1-22). Dagstuhl, Germany: Leibniz-Zentrum für Informatik
Open this publication in new window or tab >>Refinement of workload models for engine controllers by state space partitioning
2017 (English)In: 29th Euromicro Conference on Real-Time Systems: ECRTS 2017, Dagstuhl, Germany: Leibniz-Zentrum für Informatik , 2017, p. 11:1-22Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Dagstuhl, Germany: Leibniz-Zentrum für Informatik, 2017
Series
Leibniz International Proceedings in Informatics (LIPIcs), ISSN 1868-8969 ; 76
National Category
Computer Systems
Identifiers
urn:nbn:se:uu:diva-326690 (URN)10.4230/LIPIcs.ECRTS.2017.11 (DOI)978-3-95977-037-8 (ISBN)
Conference
ECRTS 2017, June 27–30, Dubrovnik, Croatia
Projects
UPMARC
Available from: 2017-06-30 Created: 2017-07-22 Last updated: 2017-07-25Bibliographically approved
Abdullah, J., Mohaqeqi, M. & Yi, W. (2017). Synthesis of Ada code from graph-based task models. In: Proc. 32nd ACM Symposium on Applied Computing: . Paper presented at SAC 2017, April 3–7, Marrakech, Morocco (pp. 1467-1472). New York: ACM Press
Open this publication in new window or tab >>Synthesis of Ada code from graph-based task models
2017 (English)In: Proc. 32nd ACM Symposium on Applied Computing, New York: ACM Press, 2017, p. 1467-1472Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New York: ACM Press, 2017
National Category
Computer Sciences
Identifiers
urn:nbn:se:uu:diva-327082 (URN)10.1145/3019612.3019681 (DOI)978-1-4503-4486-9 (ISBN)
Conference
SAC 2017, April 3–7, Marrakech, Morocco
Projects
UPMARC
Available from: 2017-04-03 Created: 2017-08-02 Last updated: 2018-01-13Bibliographically approved
Abdullah, J., Dai, G., Guan, N., Mohaqeqi, M. & Wang, Y. (2017). Towards a Tool: TIMES-Pro for Modeling, Analysis, Simulation and Implementation of Cyber-Physical Systems. In: Aceto, L Bacci, G Bacci, G Ingolfsdottir, A Legay, A Mardare, R (Ed.), MODELS, ALGORITHMS, LOGICS AND TOOLS: ESSAYS DEDICATED TO KIM GULDSTRAND LARSEN ON THE OCCASION OF HIS 60TH BIRTHDAY. Paper presented at Conference on Models, Algorithms, Logics and Tools in Honour of Kim G. Larsen on the Occasion of his 60th Birthday, AUG 19-20, 2017, Aalborg Univ, Aalborg, DENMARK (pp. 623-639). SPRINGER INTERNATIONAL PUBLISHING AG
Open this publication in new window or tab >>Towards a Tool: TIMES-Pro for Modeling, Analysis, Simulation and Implementation of Cyber-Physical Systems
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2017 (English)In: MODELS, ALGORITHMS, LOGICS AND TOOLS: ESSAYS DEDICATED TO KIM GULDSTRAND LARSEN ON THE OCCASION OF HIS 60TH BIRTHDAY / [ed] Aceto, L Bacci, G Bacci, G Ingolfsdottir, A Legay, A Mardare, R, SPRINGER INTERNATIONAL PUBLISHING AG , 2017, p. 623-639Conference paper, Published paper (Refereed)
Abstract [en]

We consider a Cyber-Physical System (CPS) as a network of components that are either physical plants with continuous behaviors or discrete controllers. To build CPS's in a systematic manner, the TIMES-Pro tool is designed to support modeling, analysis and code generation for real-time simulation and final deployment. In this paper, we present our decisions in designing the modeling language, the tool architecture and features of TIMES-Pro, and also a case study to demonstrate its applicability.

Place, publisher, year, edition, pages
SPRINGER INTERNATIONAL PUBLISHING AG, 2017
Series
Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 10460
Keywords
Cyber-Physical System, Timing analysis, Real-time simulation, Automated code generation
National Category
Computer Sciences
Identifiers
urn:nbn:se:uu:diva-365175 (URN)10.1007/978-3-319-63121-9_31 (DOI)000441452500031 ()978-3-319-63121-9 (ISBN)978-3-319-63120-2 (ISBN)
Conference
Conference on Models, Algorithms, Logics and Tools in Honour of Kim G. Larsen on the Occasion of his 60th Birthday, AUG 19-20, 2017, Aalborg Univ, Aalborg, DENMARK
Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2018-11-09Bibliographically approved
Mohaqeqi, M., Abdullah, J. & Yi, W. (2016). Modeling and analysis of data flow graphs using the digraph real-time task model. In: Reliable Software Technologies — Ada-Europe 2016: . Paper presented at Ada-Europe 2016, June 13–17, Pisa, Italy (pp. 15-29). Springer
Open this publication in new window or tab >>Modeling and analysis of data flow graphs using the digraph real-time task model
2016 (English)In: Reliable Software Technologies — Ada-Europe 2016, Springer, 2016, p. 15-29Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Springer, 2016
Series
Lecture Notes in Computer Science ; 9695
National Category
Computer Engineering
Identifiers
urn:nbn:se:uu:diva-295513 (URN)10.1007/978-3-319-39083-3_2 (DOI)000386324400002 ()978-3-319-39082-6 (ISBN)
Conference
Ada-Europe 2016, June 13–17, Pisa, Italy
Projects
UPMARC
Available from: 2016-05-31 Created: 2016-06-07 Last updated: 2018-01-10Bibliographically approved
Mohaqeqi, M., Ekberg, P. & Yi, W. (2016). On fixed-priority schedulability analysis of sporadic tasks with self-suspension. In: Proc. 24th International Conference on Real-Time Networks and Systems: . Paper presented at RTNS 2016, October 19–21, Brest, France (pp. 109-118). New York: ACM Press
Open this publication in new window or tab >>On fixed-priority schedulability analysis of sporadic tasks with self-suspension
2016 (English)In: Proc. 24th International Conference on Real-Time Networks and Systems, New York: ACM Press, 2016, p. 109-118Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New York: ACM Press, 2016
National Category
Embedded Systems
Identifiers
urn:nbn:se:uu:diva-305963 (URN)10.1145/2997465.2997485 (DOI)000391255400011 ()978-1-4503-4787-7 (ISBN)
Conference
RTNS 2016, October 19–21, Brest, France
Available from: 2016-10-19 Created: 2016-10-24 Last updated: 2017-03-16Bibliographically approved
Mohaqeqi, M., Nasri, M., Xu, Y., Cervin, A. & Årzén, K.-E. (2016). On the problem of finding optimal harmonic periods. In: Proc. 24th International Conference on Real-Time Networks and Systems: . Paper presented at RTNS 2016, October 19–21, Brest, France (pp. 171-180). New York: ACM Press
Open this publication in new window or tab >>On the problem of finding optimal harmonic periods
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2016 (English)In: Proc. 24th International Conference on Real-Time Networks and Systems, New York: ACM Press, 2016, p. 171-180Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New York: ACM Press, 2016
National Category
Embedded Systems
Identifiers
urn:nbn:se:uu:diva-305974 (URN)10.1145/2997465.2997490 (DOI)000391255400017 ()978-1-4503-4787-7 (ISBN)
Conference
RTNS 2016, October 19–21, Brest, France
Note

Best Paper Award

Available from: 2016-10-19 Created: 2016-10-24 Last updated: 2017-03-16Bibliographically approved
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