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Tanasa, Bogdan
Publications (10 of 10) Show all publications
Tanasa, B., Bordoloi, U. D., Eles, P. & Peng, Z. (2016). Correlation-Aware Probabilistic Timing Analysis for the Dynamic Segment of FlexRay. ACM Transactions on Embedded Computing Systems, 15(3), 54:1-54:31
Open this publication in new window or tab >>Correlation-Aware Probabilistic Timing Analysis for the Dynamic Segment of FlexRay
2016 (English)In: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 15, no 3, p. 54:1-54:31Article in journal (Refereed) Published
Abstract [en]

We propose an analytical framework for probabilistic timing analysis of the event-triggered Dynamic segment of the FlexRay communication protocol. Specifically, our framework computes the Deadline Miss Ratio of each message. The core problem is formulated as a Mixed Integer Linear Program (MILP). Given the intractability of the problem, we also propose several techniques that help to mitigate the running times of our tool. This includes the re-engineering of the problem to run it on GPUs as well as reformulating the MILP itself.

Most importantly, we also show how our framework can handle correlations between the queuing events of messages. This is challenging because one cannot apply the convolution operator in the same way as in the case of independent queuing events.

Place, publisher, year, edition, pages
Association for Computing Machinery (ACM), 2016
Keywords
Automotive networks, correlations, deadline miss ratio, dynamic seg- ment, flexray, probabilistic analysis, timing analysis
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-128836 (URN)10.1145/2870635 (DOI)000381422700015 ()
Available from: 2016-06-01 Created: 2016-06-01 Last updated: 2018-01-10
Xu, Y., Årzen, K.-E., Cervin, A., Bini, E. & Tanasa, B. (2015). Exploiting Job Response-Time Information in the Co-Design of Real-Time Control Systems. In: 2015 IEEE 21ST INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS: . Paper presented at 2015 IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications, 19-21 Aug. 2015 Hong Kong (pp. 247-256). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Exploiting Job Response-Time Information in the Co-Design of Real-Time Control Systems
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2015 (English)In: 2015 IEEE 21ST INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS, Institute of Electrical and Electronics Engineers (IEEE), 2015, p. 247-256Conference paper, Published paper (Refereed)
Abstract [en]

We consider a real-time system of multiple tasks, each task having a plant to control. The overall quadratic control cost is to be optimized. We exploit the periodicity of the task response time, which corresponds to a periodic delay pattern in the feedback control loop. Perturbed periods are used as a tool to find a finite hyper period. We present an analytical procedure to design a periodic linear-quadratic-Gaussian (LQG) controller for tasks with fixed execution times as well as a numerical solution to the periodic -- stochastic LQG problem for tasks with variable execution times. The controllers are evaluated using simulations in real-time scheduling and control co-design examples.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2015
Series
IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, ISSN 1533-2306
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-124404 (URN)10.1109/RTCSA.2015.23 (DOI)000378419800026 ()978-1-4673-7855-0 (ISBN)
Conference
2015 IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications, 19-21 Aug. 2015 Hong Kong
Available from: 2016-01-28 Created: 2016-01-28 Last updated: 2018-01-10
Tanasa, B., Bordoloi, U. D., Eles, P. & Peng, Z. (2015). Probabilistic Response Time and Joint Analysis of Periodic Tasks. In: PROCEEDINGS OF THE 2015 27TH EUROMICRO CONFERENCE ON REAL-TIME SYSTEMS (ECRTS 2015): . Paper presented at 27th Euromicro Conference on Real-Time Systems (ECRTS), Lund, Sweden, 8-10 July 2015 (pp. 235-246). IEEE Communications Society
Open this publication in new window or tab >>Probabilistic Response Time and Joint Analysis of Periodic Tasks
2015 (English)In: PROCEEDINGS OF THE 2015 27TH EUROMICRO CONFERENCE ON REAL-TIME SYSTEMS (ECRTS 2015), IEEE Communications Society, 2015, p. 235-246Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we address the problem of computing the probability response time distribution of periodic tasks scheduled on a uniprocessor systems. Our framework assumes an arbitrary non-idling preemptive scheduling policy that may be either a fixed-priority scheduler (such as Rate Monotonic - RM) or a dynamic-priority scheduler (such as Earliest Deadline First - EDF). At the same time, our framework can handle arbitrary execution time distributions arbitrary deadlines providing numerically accurate results. We also show how the framework can be extended to compute the correlation coefficients between the response times of different jobs by performing the joint analysis.

Place, publisher, year, edition, pages
IEEE Communications Society, 2015
Series
Euromicro Conference on Real-Time Systems. Proceedings, ISSN 1068-3070
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-123742 (URN)10.1109/ECRTS.2015.28 (DOI)000375052900021 ()978-1-4673-7570-2 (ISBN)
Conference
27th Euromicro Conference on Real-Time Systems (ECRTS), Lund, Sweden, 8-10 July 2015
Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2018-01-10Bibliographically approved
Tanasa, B. (2015). Timing Analysis of Distributed Embedded Systems with Stochastic Workload and Realiability Constraints. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Timing Analysis of Distributed Embedded Systems with Stochastic Workload and Realiability Constraints
2015 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

Today's distributed embedded systems are exposed to large variations in workload due to complex software applications and sophisticated hardware platforms. Examples of such systems are automotive and avionics applications.

The tasks running on computational units have variable execution times. Thus, the workload that the computational units must accommodate is likely to be stochastic. Some of the tasks trigger messages that will be transmitted over communication buses. There is a direct connection between the variable execution times of the tasks and the moments of triggering of these messages. Thus, the workload imposed on the communication buses will also be stochastic. The likelihood for transient faults to occur is another dimension for stochastic workload as today's embedded systems are designed to work in extreme environmental conditions. Given the above, the need for tools that can analyze systems that experience stochastic workload is continuously increasing.

The present thesis addresses this need. The solutions proposed in this thesis have been validated by extensive experiments that demonstrate the efficiency of the presented techniques.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015. p. 177
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1685
Keywords
embedded systems, perfomance analysis, real-time systems, distributed systems, fault tolerance, probabilistic analysis
National Category
Computer Systems
Identifiers
urn:nbn:se:liu:diva-119894 (URN)10.3384/diss.diva-119894 (DOI)978-91-7519-022-8 (ISBN)
Public defence
2015-09-08, Visionen, Hus B, Campus Valla, Linköpings universitet, Linköping, 13:15 (English)
Opponent
Supervisors
Funder
CUGS (National Graduate School in Computer Science)
Available from: 2015-08-18 Created: 2015-06-29 Last updated: 2015-08-18Bibliographically approved
Tanasa, B., Bordoloi, U., Eles, P. I. & Peng, Z. (2013). Probabilistic Timing Analysis for the Dynamic Segment of FlexRay. In: 25th Euromicro Conference on Real-Time Systems (ECRTS): . Paper presented at 25th Euromicro Conference on Real-Time Systems (ECRTS), 9-12 July 2013, Paris (pp. 135-144). IEEE
Open this publication in new window or tab >>Probabilistic Timing Analysis for the Dynamic Segment of FlexRay
2013 (English)In: 25th Euromicro Conference on Real-Time Systems (ECRTS), IEEE , 2013, p. 135-144Conference paper, Published paper (Refereed)
Abstract [en]

We propose an analytical framework for probabilistic timing analysis of the event-triggered Dynamic segment of the FlexRay communication protocol. Specifically, our framework computes the Deadline Miss Ratios of each message. The core problem is formulated as a Mixed Integer Linear Program (MILP). Given the intractability of the problem, we also propose several techniques that help to mitigate the running times of our tool. This includes the re-engineering of the problem to run it on GPUs as well as re-formulating the MILP itself.

Place, publisher, year, edition, pages
IEEE, 2013
Series
EUROMICRO Conference on Real-Time Systems, ISSN 1068-3070
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-106540 (URN)10.1109/ECRTS.2013.24 (DOI)000333895000014 ()978-076955054-1 (ISBN)
Conference
25th Euromicro Conference on Real-Time Systems (ECRTS), 9-12 July 2013, Paris
Available from: 2014-05-12 Created: 2014-05-09 Last updated: 2015-05-28Bibliographically approved
Bordoloi, U. D., Tanasa, B., Eles, P. & Peng, Z. (2012). On the Timing Analysis of the Dynamic Segment of FlexRay. In: International Symposium on Industrial Embedded Systems (SIES 2012), Karlsruhe, Germany, June 20-22, 2012.: . Paper presented at SIES12.
Open this publication in new window or tab >>On the Timing Analysis of the Dynamic Segment of FlexRay
2012 (English)In: International Symposium on Industrial Embedded Systems (SIES 2012), Karlsruhe, Germany, June 20-22, 2012., 2012Conference paper, Published paper (Other academic)
Abstract [en]

FlexRay, developed by a consortium of over hundred automotive companies, is a real-time communication protocol for automotive networks. A communication cycle in FlexRay consists of an event-triggered component known as the dynamic (DYN) segment, apart from a time-triggered segment. Predicting the worst-case response time of messages transmitted on the DYN segment is a difficult problem. This is because a set of complex rules, apart from the priorities of the messages, govern the DYN segment protocol. In this paper, we survey techniques for the timing analysis of the DYN segment. We discuss the challenges associated with the timing analysis of the FlexRay protocol, the proposed techniques and their limitations.

National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:liu:diva-78640 (URN)10.1109/SIES.2012.6356574 (DOI)978-1-4673-2685-8 (ISBN)978-1-4673-2683-4 (ISBN)
Conference
SIES12
Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2018-01-12
Bordoloi, U. D., Tanasa, B., Tahoori, M. B., Eles, P., Peng, Z., Shazli, S. Z. & Chakraborty, S. (2012). Reliability-Aware Instruction Set Customization for ASIPs with Hardened Logic. In: International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2012), Seoul, Korea, August 19-22, 2012.: . Paper presented at RTCSA12.
Open this publication in new window or tab >>Reliability-Aware Instruction Set Customization for ASIPs with Hardened Logic
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2012 (English)In: International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2012), Seoul, Korea, August 19-22, 2012., 2012Conference paper, Published paper (Refereed)
Abstract [en]

Application-specific instruction-set processors (ASIPs) allow the designer to extend the instruction set of the base processor with selected custom instructions to tailor-fit the application.In this paper, with the help of a motivational example, we first demonstrate that different custom instructions are vulnerable to faults with varying probabilities. This shows that by ignoring the vulnerability to faults, traditional methods of instruction set customization can provide no guarantees on the reliability of the system. Apart from such inherent disparity in error vulnerability across custom instructions, each custom instruction can have multiple implementation choices corresponding to varying hardened levels. Hardening reduces the vulnerability to errors but this comes at the overhead of area costs and reduced performance gain. In this paper, we propose a framework to select custom instructions and their respective hardening levels such that reliability is optimized while the performance gain is satisfied and area costs are met as well. Our framework is based on a novel analytical method to compute the overall system reliability based on the probability of failure of individual instructions. Wide range of experiments that were conducted illustrate how our tool navigates the design space to reveal interesting tradeoffs.

National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:liu:diva-78639 (URN)10.1109/RTCSA.2012.28 (DOI)978-1-4673-3017-6 (ISBN)978-0-7695-4824-1 (ISBN)
Conference
RTCSA12
Available from: 2012-06-15 Created: 2012-06-15 Last updated: 2018-01-12
Tanasa, B., Bordoloi, U., Kosuch, S., Eles, P. I. & Peng, Z. (2012). Schedulability Analysis for the Dynamic Segment of FlexRay: A Generalization to Slot Multiplexing. In: : . Paper presented at 2012 IEEE 18th Real Time and Embedded Technology and Applications Symposium (RTAS), 16-19 April 2012, Beijing (pp. 185-194). IEEE
Open this publication in new window or tab >>Schedulability Analysis for the Dynamic Segment of FlexRay: A Generalization to Slot Multiplexing
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2012 (English)Conference paper, Published paper (Refereed)
Abstract [en]

FlexRay, developed by a consortium of over hundred automotive companies, is a real-time communication protocol for automotive networks. In this paper, we propose a new approach for timing analysis of the event-triggered component of FlexRay, known as the dynamic segment. Our technique accounts for the fact that the FlexRay standard allows slot multiplexing, i.e., the same priority can be assigned to more than one message. Existing techniques have either ignored slot multiplexing in their analysis or made simplifying assumptions that severely limit achieving high bandwidth utilization. Moreover, we show that our technique returns less pessimistic results compared to previously known techniques even in the case where slot multiplexing is ignored.

Place, publisher, year, edition, pages
IEEE, 2012
Keywords
FlexRay, Slot Multiplexing, Timing Analysis
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-87593 (URN)10.1109/RTAS.2012.10 (DOI)000309190700018 ()978-1-4673-0883-0 (ISBN)
Conference
2012 IEEE 18th Real Time and Embedded Technology and Applications Symposium (RTAS), 16-19 April 2012, Beijing
Available from: 2013-01-18 Created: 2013-01-18 Last updated: 2017-12-13
Tanasa, B., Bordoloi, U. D., Eles, P. & Peng, Z. (2011). Reliability-Aware Frame Packing for the Static Segment of FlexRay. In: EMSOFT '11 Proceedings of the ninth ACM international conference on Embedded software                         : . Paper presented at The Intl. Conf. on Embedded Software (EMSOFT11), Taipei, Taiwan, October 9-14, 2011. (pp. 175-184). Association for Computing Machinery (ACM)
Open this publication in new window or tab >>Reliability-Aware Frame Packing for the Static Segment of FlexRay
2011 (English)In: EMSOFT '11 Proceedings of the ninth ACM international conference on Embedded software                         , Association for Computing Machinery (ACM), 2011, p. 175-184Conference paper, Published paper (Refereed)
Abstract [en]

FlexRay is gaining wide acceptance as the next generation bus protocol for automotive networks. This has led to tremendous research interest in techniques for scheduling signals, which are generated by real-time applications, on the FlexRay bus. Signals are first packed together into frames at the application-level and the frames are then transmitted over the bus. To ensure reliability of frames in the presence of faults, frames must be retransmitted over the bus but this comes at the cost of higher bandwidth utilization. To address this issue, in this paper, we propose a novel frame packing method for FlexRay bus. Our method computes the required number of retransmissions of frames that ensures the specified reliability goal. The proposed frame packing method also ensures that none of the signals violates its deadline and that the desired reliability goal for guaranteeing fault-tolerance is met at the minimum bandwidth cost. Extensive experiments on synthetic as well as a industrial case study demonstrate the benefits of our method.

Place, publisher, year, edition, pages
Association for Computing Machinery (ACM), 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-69734 (URN)10.1145/2038642.2038670 (DOI)978-1-4503-0714-7 (ISBN)
Conference
The Intl. Conf. on Embedded Software (EMSOFT11), Taipei, Taiwan, October 9-14, 2011.
Available from: 2011-08-01 Created: 2011-08-01 Last updated: 2017-02-14
Tanasa, B., Bordoloi, U. D., Eles, P. & Peng, Z. (2010). Scheduling for Fault-Tolerant Communication on the Static Segment of FlexRay. In: 31st IEEE Real-Time Systems Symposium (RTSS10), San Diego, CA, USA, November 30-December 3, 2010.: . Paper presented at 31st IEEE Real-Time Systems Symposium (RTSS10), San Diego, CA, USA, November 30-December 3, 2010. (pp. 385-394). IEEE Computer Society
Open this publication in new window or tab >>Scheduling for Fault-Tolerant Communication on the Static Segment of FlexRay
2010 (English)In: 31st IEEE Real-Time Systems Symposium (RTSS10), San Diego, CA, USA, November 30-December 3, 2010., IEEE Computer Society , 2010, p. 385-394Conference paper, Published paper (Refereed)
Abstract [en]

FlexRay has been widely accepted as the next generation bus protocol for automotive networks. This has led to tremendous research interest in techniques for scheduling messages on the FlexRay bus, in order to meet the hard realtime deadlines of the automotive applications. However, these techniques do not generate reliable schedules in the sense that they do not provide any performance guarantees in the presence of faults. In this work, we will present a framework for generating fault-tolerant message schedules on the time-triggered (static) segment of the FlexRay bus. We provide formal guarantees that the generated fault-tolerant schedules achieve the reliability goal even in the presence of transient and intermittent faults. Moreover, our technique minimizes the required number of retransmissions of the messages in order to achieve such fault tolerant schedules, thereby, optimizing the bandwidth utilization. Towards this, we formulate the optimization problem in Constraint Logic Programming (CLP), which returns optimal results. However, this procedure is computationally intensive and hence, we also propose an efficient heuristic. The heuristic guarantees the reliability of the constructed schedules but might be sub-optimal with respect to bandwidth utilization. Extensive experiments run on synthetic test cases and real-life case studies illustrate that the heuristic performs extremely well. The experiments also establish that our heuristic scales significantly better than the CLP formulation.

Place, publisher, year, edition, pages
IEEE Computer Society, 2010
Series
REAL-TIME SYSTEMS SYMPOSIUM/IEEE Computer Society, ISSN 1052-8725
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-59630 (URN)10.1109/RTSS.2010.31 (DOI)978-0-7695-4298-0 (ISBN)
Conference
31st IEEE Real-Time Systems Symposium (RTSS10), San Diego, CA, USA, November 30-December 3, 2010.
Available from: 2010-09-29 Created: 2010-09-22 Last updated: 2013-09-10Bibliographically approved
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