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  • 1.
    Achuthan, K.
    et al.
    Amrita Center for Cybersecurity Systems and Networks, Kerala, India.
    Ramesh, M. V.
    Amrita Center for International Programs, Kerala, India.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Raman, R.
    Center for Research in Advanced Technologies for Education, Kerala, India.
    Internationalizing engineering education with phased study programs: India-European experience2015Ingår i: Proceedings - Frontiers in Education Conference, FIE, 2015, nr FebruaryKonferensbidrag (Refereegranskat)
    Abstract [en]

    Most of the critical challenges seen in the past decades have impacted citizens in a global way. Given shrinking resources, educationists find preparing students for the global market place a formidable challenge. Hence exposing students to multi-lateral educational initiatives are critical to their growth, understanding and future contributions. This paper focuses on European Union's Erasmus Mundus programs, involving academic cooperation amongst international universities in engineering programs. A phased undergraduate engineering program with multiple specializations is analyzed within this context. Based on their performance at the end of first phase, selected students were provided opportunities using scholarship to pursue completion of their degree requirements at various European universities. This paper will elaborate the impact of differing pedagogical interventions, language and cultural differences amongst these countries on students in diverse engineering disciplines. The data presented is based on on the feedback analysis from Eramus Mundus students (N=121) that underwent the mobility programs. The findings have given important insights into the structure of the initiative and implications for academia and education policy makers for internationalizing engineering education. These included considering digital interventions such as MOOCs (Massive Open Online Courses) and Virtual Laboratory (VL) initiatives for systemic reorganization of engineering education.

  • 2.
    Achuthan, Krishnashree
    et al.
    Amrita Vishwa Vidyapeetham, Amrita Ctr Cybersecur Syst & Networks, Kollam, Kerala, India..
    Ramesh, Maneesha V.
    Amrita Vishwa Vidyapeetham, Amrita Ctr Int Programs, Kollam, Kerala, India..
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Raman, Raghu
    Amrita Vishwa Vidyapeetham, Ctr Res Adv Technol Educ, Kollam, Kerala, India..
    Internationalizing Engineering Education With Phased Study Programs: India-European Experience2014Ingår i: 2014 IEEE FRONTIERS IN EDUCATION CONFERENCE (FIE), IEEE , 2014, s. 295-301Konferensbidrag (Refereegranskat)
    Abstract [en]

    Most of the critical challenges seen in the past decades have impacted citizens in a global way. Given shrinking resources, educationists find preparing students for the global market place a formidable challenge. Hence exposing students to multi-lateral educational initiatives are critical to their growth, understanding and future contributions. This paper focuses on European Union's Erasmus Mundus programs, involving academic cooperation amongst international universities in engineering programs. A phased undergraduate engineering program with multiple specializations is analyzed within this context. Based on their performance at the end of first phase, selected students were provided opportunities using scholarship to pursue completion of their degree requirements at various European universities. This paper will elaborate the impact of differing pedagogical interventions, language and cultural differences amongst these countries on students in diverse engineering disciplines. The data presented is based on on the feedback analysis from Eramus Mundus students (N = 121) that underwent the mobility programs. The findings have given important insights into the structure of the initiative and implications for academia and education policy makers for internationalizing engineering education. These included considering digital interventions such as MOOCs (Massive Open Online Courses) and Virtual Laboratory (VL) initiatives for systemic reorganization of engineering education.

  • 3.
    Aysan, Huseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bate, Iain
    University of York.
    Graydon, Patrick
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Improving Reliability of Real-Time Systems through Value and Time Voting2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Critical systems often use N-modular redundancy to tolerate faults in subsystems. Traditional approaches to N-modular redundancy in distributed, loosely-synchronised, real-time systems handle time and value errors separately: a voter detects value errors, while watchdog-based health monitoring detects timing errors. In prior work, we proposed the integrated Voting on Time and Value (VTV) strategy, which allows both timing and value errors to be detected simultaneously. In this paper, we show how VTV can be harnessed as part of an overall fault tolerance strategy and evaluate its performance using a well-known control application, the Inverted Pendulum. Through extensive simulations, we compare the performance of Inverted Pendulum systems which employs VTV and alternative voting strategies to demonstrate that VTV better tolerates well-recognised faults in this realistically complex control problem.

  • 4.
    Aysan, Huseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Susikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Schedulability guarantees for dependable distributed real-time systems under error bursts2013Ingår i: Advances in Intelligent Systems and Computing, Springer Verlag , 2013, Vol. 187, s. 393-406Konferensbidrag (Refereegranskat)
    Abstract [en]

    In dependable embedded real-time systems, typically built of computing nodes exchanging messages over reliability-constrained networks, the provision of schedulability guarantees for task and message sets under realistic fault and error assumptions is an essential requirement, though complex and tricky to achieve. An important factor to be considered in this context is the random nature of occurrences of faults and errors, which, if addressed in the traditional schedulability analysis by assuming a rigid worst-case occurrence scenario, may lead to inaccurate results. In this work we propose a framework for end-to-end probabilistic schedulability analysis for real-time tasks exchanging messages over Controller Area Network under stochastic errors.

  • 5.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Dobrin, Radu
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    A Generalized Task Allocation Framework for Dependable Real-Time Systems2007Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS 07), 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a general framework which allows the designer to specify a wide range of criteria for allocation. Major factors considered as part of our framework are mixed criticalities of tasks, schedulability, power consumption, fault-tolerance, and dependability requirements in addition to typical functional aspects such as memory constraints. This being a global optimization problem, we are forced to use meta-heuristic algorithms, and we were able to represent these requirements in a very intuitive manner by the usage of energy functions in simulated annealing. We envision the proposed methodology as a quite simple, scalable, as well as computationally effective solution covering a wide range of system architectures and solution spaces. 

  • 6.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Fault Tolerant Scheduling on Control Area Network (CAN):  2010Ingår i: ISORC Workshops 2010 - 2010 13th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing Workshops, Vol. 2, 2010, s. 226-232Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dependable communications is becoming a critical factor due to the pervasive usage of networked embedded systems that increasingly interact with human lives in one way or the other in many real-time applications. Though many smaller systems are providing dependable services employing uniprocesssor solutions, stringent fault containment strategies etc., these practices are fast becoming inadequate due to the prominence of COTS in hardware and component based development(CBD) in software as well as the increased focus on building 'system of systems'. Hence the repertoire of design paradigms, methods and tools available to the developers of distributed real-time systems needs to be enhanced in multiple directions and dimensions. In future scenarios, potentially a network needs to cater to messages of multiple criticality levels (and hence varied redundancy requirements) and scheduling them in a fault tolerant manner becomes an important research issue. We address this problem in the context of Controller Area Network (CAN), which is widely used in automotive and automation domains, and describe a methodology which enables the provision of appropriate scheduling guarantees. The proposed approach involves definition of fault-tolerant windows of execution for critical messages and the derivation of message priorities based on earliest deadline first (EDF).

  • 7.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Dobrin, Radu
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    FT-Feasibility in Fixed Priority Real-Time Scheduling2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Real-time systems typically have to satisfy complex requirements mapped to the timing attributes of the tasks that are eventually guaranteed by the underlying scheduler. These systems consist of a mix of hard and soft tasks with varying criticalities as well as associated fault tolerance (FT) requirements. Often time redundancy techniques are preferred in many embedded applications and hence it is extremely important to devise appropriate methodologies for scheduling real-time tasks under fault assumptions. Additionally, the relative criticality of tasks could undergo changes during the evolution of the system. Hence scheduling decisions under fault assumptions have to reflect all these important factors in addition to the resource constraints.

    In this paper we propose a framework for 'FTfeasibility', i.e., to provide a priori guarantees that all critical tasks in the system will meet their deadlines even in case of faults. Our main objective here is to ensure FTfeasibility of all critical tasks in the system and do so with minimal costs and without any fundamental changes in the scheduling paradigm. We demonstrate its applicability in scenarios where the FT strategy employed is re-execution of the affected tasks or an alternate action upon occurrence of transient faults or software design faults. We analyse a feasible set of tasks and propose methods to adapt it to varying FT requirements without modifications to the underlying scheduler. We do so by reassigning task attributes to achieve FT-feasibility while keeping the costs minimised.

  • 8.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Probabilistic schedulability analysis for fault tolerant tasks under stochastic error occurrences2013Ingår i: 19th International Conference on Control Systems and Computer Science, CSCS 2013: Proceedings, 2013, s. 113-120Konferensbidrag (Refereegranskat)
    Abstract [en]

    In dependable real-time systems, provision of schedulability guarantees for task sets under realistic fault and error assumptions is an essential requirement, though complex and tricky to achieve. An important factor to be considered in this context is the random nature of occurrences of faults and errors, which, if addressed in the traditional schedulability analysis by assuming a rigid worst case occurrence scenario, may lead to inaccurate results. In this paper we first propose a stochastic fault and error model which has the capability of modeling error bursts in lieu of the commonly used simplistic error assumptions in processor scheduling. We then present a novel schedulability analysis that accounts for a range of worst case scenarios generated by stochastic error burst occurrences on the response times of tasks scheduled under the fixed priority scheduling (FPS) policy. Finally, we describe a methodology for the calculation of probabilistic schedulability guarantees as a weighted sum of the conditional probabilities of schedulability under specified error burst characteristics.

  • 9.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Task-Level Probabilistic Scheduling Guarantees for Dependable Real-Time Systems: A designer centric approach  2011Ingår i: Proceedings - 2011 14th IEEE International Symposium on Object/Component/Service-Oriented Real-Time Distributed Computing Workshops, ISORCW 2011, 2011, s. 281-287Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dependable real-time systems typically consist of tasks of mixed-criticality levels with associated fault tolerance (FT) requirements and scheduling them in a fault-tolerant manner to efficiently satisfy these requirements is a challenging problem. From the designers' perspective, the most natural way to specify the task criticalities is by expressing the reliability requirements at task level, without having to deal with low level decisions, such as deciding on which FT method to use, where in the system to implement the FT and the amount of resources to be dedicated to the FT mechanism. Hence, it is extremely important to devise methods for translating the highlevel requirement specifications for each task into the low-level scheduling decisions needed for the FT mechanism to function efficiently and correctly. In this paper, we focus achieving FT by redundancy in the temporal domain, as it is the commonly preferred method in embedded applications to recover from transient and intermittent errors, mainly due to its relatively low cost and ease of implementation. We propose a method which allows the system designer to specify task-level reliability requirements and provides a priori probabilistic scheduling guarantees for real-time tasks with mixed-criticality levels in the context of preemptive fixed-priority scheduling. We illustrate the method on a running example.

  • 10.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Dobrin, Radu
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Towards an Error Modeling Framework for Dependable Component Based Systems2008Ingår i: DATE Workshop on Dependable Software Systems, 2008Konferensbidrag (Refereegranskat)
  • 11.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    Mälardalens högskola, Akademin för innovation, design och teknik.
    On Voting Strategies for Loosely Synchronized Dependable Real-Time Systems2012Ingår i: 7th IEEE International Symposium on Industrial Embedded Systems, 2012, s. 120-129Konferensbidrag (Refereegranskat)
    Abstract [en]

    Hard real-time applications typically have to satisfy high dependability requirements in terms of fault tolerance in both the value and the time domains. Loosely synchronized real-time systems, which represent many of the systems that are developed, make any form of voting difficult as each replica may provide different outputs independent of whether there has been an error or not. This can also lead to false positives and false negatives which makes achieving fault tolerance, and hence dependability, difficult. We have earlier proposed a majority voting technique, ”Voting on Time and Value” (VTV) that explicitly considers combinations of value and timing errors, targeting loosely synchronised systems. In this paper, we extend VTV to enable voter parameter tuning to obtain the desired user specified trade-offs between the false positive and false negative rates in the voter outputs. We evaluate the performance of VTV against Compare Majority Voting (CMV), which is a known voting approach applicable in similar contexts, through extensive simulation studies. The results clearly demonstrate that VTV outperforms CMV in all scenarios with lower false negative rates.

  • 12.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Johansson, R.
    SP Technical Research Institute of Sweden.
    Probabilistic schedulability guarantees for dependable real-time systems under error bursts2011Ingår i: Proc. 10th IEEE Int. Conf. on Trust, Security and Privacy in Computing and Communications, TrustCom 2011, 8th IEEE Int. Conf. on Embedded Software and Systems, ICESS 2011, 6th Int. Conf. on FCST 2011, 2011, s. 1154-1163Konferensbidrag (Refereegranskat)
    Abstract [en]

    The fundamental requirement for the design of effective and efficient fault-tolerance mechanisms in dependable real-time systems is a realistic and applicable model of potential faults, their manifestations and consequences. Fault and error models also need to be evolved based on the characteristics of the operational environments or even based on technological advances. In this paper we propose a probabilistic burst error model in lieu of the commonly used simplistic fault assumptions in the context of processor scheduling. We present a novel schedulability analysis that accounts for the worst case interference caused by error bursts on the response times of tasks scheduled under the fixed priority scheduling (FPS) policy. Further, we describe a methodology for the calculation of probabilistic schedulability guarantees as a weighted sum of the conditional probabilities of schedulability under specified error burst characteristics. Finally, we identify potential sources of pessimism in the worst case response time calculations and discuss potential means for circumventing these issues.

  • 13.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Proenza, Julian
    University of the Balearic Islands, Palma de Mallorca.
    Probabilistic Scheduling Guarantees in Distributed Real-Time Systems under Error Bursts2012Ingår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA 2012, 2012, s. Article number: 6489644-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Networked embedded systems used in many real-time (RT) applications rely on dependable communication. Controller Area Network (CAN) has gained wider acceptance as a standard in a large number of applications, mostly due to its cost effectiveness, predictable performance, and its fault-tolerance capability. Research so far has focused on rather simplistic error models which assume only singleton errors separated by a minimum inter-arrival time. However, these systems are often subject to faults that manifest as error bursts of various lengths which have an adverse effect on the message response times that needs to be accounted for. Furthermore, an important factor to be considered in this context is the random nature of occurrences of faults and errors, which, if addressed in the traditional schedulability analysis by assuming a rigid worst case occurrence scenario, may lead to inaccurate results. In this paper we first present a stochastic fault and error model which has the capability of modeling error bursts in lieu of the commonly used simplistic error assumptions. We then present a methodology which enables the provision of appropriate probabilistic RT guarantees in distributed RT systems for the particular case of message scheduling on CAN under the assumed error assumptions

  • 14.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Generalised Error Model and Schedulability Guarantees for Dependable Real-Time Systems2011Ingår i: Proceedings of the 1st International Workshop on Dependable and Secure Industrial and Embedded Systems (WORDS), 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    The fundamental requirement for the design of effective and efficient fault-tolerance mechanisms in dependable real-time systems is a realistic and applicable model of potential faults, their manifestations and consequences. Fault and error models also need to be evolved based on the changes in the environments of usage or even based on technological advances. In this paper we propose a novel probabilistic burst error model in lieu of the commonly used simplistic fault assumptions. We introduce an approach to reason about real-time systems schedulability under the proposed error model in a probabilistic manner. We first present a sufficient analysis that accounts for the worst case interference caused by error bursts on the response times of tasks scheduled under the fixed priority scheduling (FPS) policy. Further, we identify potential sources of pessimism in the calculations and propose an algorithm that refines the results.

  • 15.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Dobrin, Radu
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    A Cascading Redundancy Approach for Dependable Real-Time Systems2009Ingår i: Proceedings - 15th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2009, 2009, s. 467-476Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dependable real-time systems typically consist of tasks of multiple criticality levels and scheduling them in a fault-tolerantmanner is a challenging problem. Redundancy in the physical and temporal domains for achieving fault tolerance has been often dealt independently based on the types of errors one needs to tolerate. To our knowledge, there had been no work which tries to integrate fault tolerant scheduling and multiple redundancy mechanisms. In this paper we propose a novel cascading redundancy approach within a generic fault tolerant scheduling framework. The proposed approach is capable of tolerating errors with a wider coverage (with respect to error frequency and error types) than time and space redundancy in isolation, allows tasks with mixed criticality levels, is independent of the scheduling technique and, above all, ensures that every critical task instance can be feasibly replicated in both time and space. 

     

  • 16.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Adding the Time Dimension to Majority Voting Strategies2008Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 14th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'08), St. Louis, MO, United States: University of Nebraska–Lincoln Technical Report TR-UNL-CSE-2008-0003, 2008, s. 69-73Konferensbidrag (Refereegranskat)
  • 17.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Error Modeling in Dependable Component-based Systems2008Ingår i: Proceedings - International Computer Software and Applications Conference, 2008, s. 1309-1314Konferensbidrag (Refereegranskat)
    Abstract [en]

    Component-Based Development (CBD) of software, with its successes in enterprise computing, has the promise of being a good development model due to its cost effectiveness and potential for achieving high quality of components by virtue of reuse. However, for systems with dependability concerns, such as real-time systems, a major challenge in using CBD consists of predicting dependability attributes, or providing dependability assertions, based on the individual component properties and architectural aspects. In this paper, we propose a framework which aims to address this challenge. Specifically, we present a revised error classification together with error propagation aspects, and briefly sketch how to compose errormodels within the context of Component-Based Systems (CBS). The ultimate goal is to perform the analysis on a given CBS, in order to find bottle-necks in achieving dependability requirements and to provide guidelines to the designer on the usage of appropriate error detection and fault tolerance mechanisms.

  • 18.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Dobrin, Radu
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    VTV -- A Voting Strategy for Real-Time Systems2008Ingår i: Proceedings of the 14th IEEE Pacific Rim International Symposium on Dependable Computing, PRDC 2008, 2008, s. 56-63Konferensbidrag (Refereegranskat)
    Abstract [en]

     

    Real-time applications typically have to satisfy high dependability requirements and require fault tolerance in both value and time domains. A widely used approach to ensure fault tolerance in dependable systems is the N-modular redundancy (NMR) which typically uses a majority voting mechanism. However, NMR primarily focuses on producing the correct value, without taking into account the time dimension. In this paper, we propose a new approach, Voting on Time and Value (VTV), applicable to real-time systems, which extends the modular redundancy approach by explicitly considering both value and timing failures, such that correct value is produced at a correct time, under specified assumptions. We illustrate our voting approach by instantiating it in the context of the well-known triple modular redundancy (TMR) approach. Further, we present a generalized version targeting NMR that enables a high degree of customization from the user perspective.

     

  • 19.
    Aysan, Hüseyin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Thekkilakattil, Abhilash
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Efficient Fault Tolerant Scheduling on Controller Area Network (CAN)2010Ingår i: Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2010, Bilbao, Spain, 2010, s. Art.nr 5641318-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dependable communication is becoming a critical factor due to the pervasive usage of networked embedded systems that increasingly interact with human lives in many real-time applications. Controller Area Network (CAN) has gained wider acceptance as a standard in a large number of industrial applications, mostly due to its efficient bandwidth utilization, ability to provide real-time guarantees, as well as its fault-tolerant capability. However, the native CAN fault-tolerant mechanism assumes that all messages transmitted on the bus are equally critical, which has an adverse impact on the message latencies, results in the inability to meet user defined reliability requirements, and, in some cases, even leads to violation of timing requirements. As the network potentially needs to cater to messages of multiple criticality levels (and hence varied redundancy requirements), scheduling them in an efficient fault-tolerant manner becomes an important research issue. We propose a methodology which enables the provision of appropriate guarantees in CAN scheduling of messages with mixed criticalities. The proposed approach involves definition of fault-tolerant feasibility windows of execution for critical messages, and off-line derivation of optimal message priorities that fulfill the user specified level of fault-tolerance.

  • 20.
    Bate, Iain
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Better, Faster, Cheaper, and Safer Too: Is This Really Possible?2012Ingår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA, 2012, s. 6489706-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Increased levels of automation together with increased complexity of automation systems brings increased responsibility on the system developers in terms of quality demands from the legal perspectives as well as company reputation. Component based development of software systems provides a viable and cost-effective alternative in this context provided one can address the quality and safety certification demands in an efficient manner. In this paper we present our vision, challenges and a brief outline of various research themes in which our team is engaged currently within two major projects.

  • 21.
    Baumgart, S.
    et al.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Zhang, X.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Variability management in product lines of safety critical embedded systems2014Ingår i: International Conference on Embedded Systems, ICES 2014, 2014, s. 98-103Konferensbidrag (Refereegranskat)
    Abstract [en]

    The product line engineering approach is a promising concept to identify and manage reuse in a structured and efficient way and is even applied for the development of safety critical embedded systems. Managing the complexity of variability and addressing functional safety at the same time is challenging and is not yet solved. Variability management is an enabler to both establish traceability and making necessary information visible for safety engineers. We identify a set of requirements for such a method and evaluate existing variability management methods. We apply the most promising method to an industrial case and study its suitability for developing safety critical product family members. This study provides positive feedback on the potential of the model-based method PLUS in supporting the development of functional safety critical embedded systems in product lines. As a result of our analysis we suggest potential improvements for it.

  • 22.
    Baumgart, Stephan
    et al.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. RISE ICT/SICS Västerås, Sweden.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Can STPA be used for a System-of-Systems? Experiences from an Automated Quarry Site2018Ingår i: 4th IEEE International Symposium on Systems Engineering, ISSE 2018 - Proceedings, 2018, nr 4, artikel-id 8544433Konferensbidrag (Refereegranskat)
    Abstract [en]

    Automation is becoming prevalent in more and more industrial domains due to the potential benefits in cost reduction as well as the new approaches/solutions they enable. When machines are automated and utilized in system-of-systems, a thorough analysis of potential critical scenarios is necessary to derive appropriate design solutions that are safe as well. Hazard analysis methods like PHA, FTA or FMEA help to identify and follow up potential risks for the machine operators or bystanders and are well-established in the development process for safety critical machinery. However, safety certified individual machines can no way guarantee safety in the context of system-of-systems since their integration and interactions could bring forth newer hazards. Hence it is paramount to understand the application sce- narios of the system-of-systems and to apply a structured method to identify all potential hazards. In this paper, we 1) provide an overview of proposed hazard analysis methods for system-of- systems, 2) describe a case from construction equipment domain, and 3) apply the well-known System-Theoretic Process Analysis (STPA)f to our case. Our experiences during the case study and the analysis of results clearly point out certain inadequacies of STPA in the context of system-of-systems and underlines the need for the development of improved techniques for safety analysis of system-of-systems.

  • 23.
    Baumgart, Stephan
    et al.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. SICS Swedish ICT, Sweden.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Defining a Method to Perform Effective Hazard Analysis for a Directed SoS Based on STPA2018Ingår i: Third Swedish Workshop on the Engineering of Systems-of-Systems 2018 SWESoS 2018, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    —Automating a quarry site as developed within the electric site research project at Volvo Construction Equipment is an example of a directed system-of-systems (SoS). In our case automated machines and connected smart systems are utilized to improve the work-flow at the site. We currently work on conducting hazard and safety analyses on the SoS level. Performing a hazard analysis on a SoS has been a challenge in terms of complexity and work effort. We elaborate on the suitability of methods, discuss requirements on a feasible method, and propose a tailoring of the STPA method to leverage complexity.

  • 24.
    Baumgart, Stephan
    et al.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. BIT-Pilani KK Birla Goa Campus, India.
    Enhancing Model-Based Engineering of Product Lines by Adding Functional Safety2015Ingår i: CEUR Workshop Proceedings, vol. 1487, 2015, s. 53-62Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today's industrial product lines in the automotive and construction equipment domain face the challenge to show functional safety standard compliance and argue for the absence of failures for all derived product variants. The product line approaches are not su cient to support practitioners to trace safety-related characteristics through development. We aim to provide aid in creating a safety case for a certain con guration in a product line such that overall less e ort is necessary for each con guration. In this paper we 1) discuss the impact of functional safety on product line development, 2) propose a model-based approach to capture safety-related characteristics during concept phase for product lines and 3) analyze the usefulness of our proposal.

  • 25.
    Baumgart, Stephan
    et al.
    Volvo Construct Equipment, E&E Syst Architecture Dept, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Industrial Challenges to Achieve Functional Safety Compliance in Product Lines2014Ingår i: 2014 40TH EUROMICRO CONFERENCE SERIES ON SOFTWARE ENGINEERING AND ADVANCED APPLICATIONS (SEAA 2014), 2014, s. 356-360Konferensbidrag (Refereegranskat)
    Abstract [en]

    Developing safety critical products demands a clear safety argumentation for each product in spite of whether it has been derived from a product line or not. The functional safety standards do not explain how to develop safety critical products in product lines, and the product line concept is lacking specific approaches to develop safety critical products. Nonetheless, product lines are well-established concepts even in companies developing safety critical products. In this paper we present the results of an exploratory study interviewing 15 practitioners from 6 different companies. We identify typical challenges and approaches from industry and discuss their suitability. The challenges and approaches brought out by this study help us to identify and enhance applicable methods from the product line engineering domain that can meet the challenges in the safety critical domain as well.

  • 26.
    Baumgart, Stephan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Efficient Functional Safety Certification of Construction Machinery using a Component-based Approach2012Ingår i: 2012 3rd International Workshop on Product LinE Approaches in Software Engineering, PLEASE 2012 - Proceedings, 2012, s. 1-4Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electronic systems in the automotive domain implement safety critical functionality in vehicles and the safety certification process according to a functional safety standard is time consuming and a big part of the expenses of a development project. We describe the functional safety certification of electronic automotive systems by presenting a use case from the construction equipment industry. In this context, we highlight some of the major challenges we foresee, while using a product-line approach to achieve efficient functional safety certification of vehicle variants. We further elaborate on the impact of functional safety certification when applying the component-based approach on developing safety critical product variants and discuss the implications by cost modeling and analysis.

  • 27.
    Baumgart, Stephan
    et al.
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Fröberg, Joakim
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Susikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Analyzing Hazards in System-of-Systems: Described in a Quarry Site Automation Context2017Ingår i: 11th Annual IEEE International Systems conference SysCon, 2017, s. 544-551Konferensbidrag (Refereegranskat)
    Abstract [en]

    Methods for analyzing hazards related to individual systems are well studied and established in industry today. When system-of-systems are set up to achieve new emergent behavior, hazards specifically caused by malfunctioning behavior of the complex interactions between the involved systems may not be revealed by just analyzing single system hazards. A structured process is required to reduce the complexity to enable identification of hazards when designing system-of-systems. In this paper we first present how hazards are identified and analyzed using hazard and risk assessment (HARA) methodology by the industry in the context of single systems. We describe systems-of-systems and provide a quarry site automation example from the construction equipment domain. We propose a new structured process for identifying potential hazards in systems-of-systems (HISoS), exemplified in the context of the provided example. Our approach helps to streamline the hazard analysis process in an efficient manner thus helping faster certification of system-of-systems.

  • 28.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Quality of Testing in Test Driven Development2012Ingår i: 2012 8th International Conference on the Quality of Information and Communications Technology, QUATIC 2012: Proceedings, IEEE , 2012, s. 266-271Konferensbidrag (Refereegranskat)
    Abstract [en]

    Test-driven development is an essential part of eXtreme Programming approach with the preference of being followed in other Agile methods as well. For several years, researchers are performing empirical investigations to evaluate quality improvements in the resulting code when test-driven development is being used. However, very little had been reported into investigating the quality of the testing performed in conjunction with test-driven development. In this paper we present results from an experiment specifically designed to evaluate the quality of test cases created by developers who used the test-first and the traditional test-last approaches. On an average, the quality of testing in test-driven development was almost the same as the quality of testing using test-last approach. However, detailed analysis of test cases, created by test-driven development group, revealed that 29% of test cases were "negative" test cases (based on non-specified requirements) but contributing as much as 65% to the overall tests quality score of test-first developers. We are currently investigating the possibility of extending test-driven development to facilitate non-specified requirements to a higher extent and thus minimise the impact of a potentially inherent effect of positive test bias.

  • 29.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    TDDHQ: Achieving Higher Quality Testing in Test Driven Development2013Ingår i: Euromicro Conference on Software Engineering and Advanced Applications, 2013, s. 33-36Konferensbidrag (Refereegranskat)
    Abstract [en]

    Test driven development (TDD) appears not to be immune to positive test bias effects, as we observed in several empirical studies. In these studies, developers created a significantly larger set of positive tests, but at the same time the number of defects detected with negative tests is significantly higher than those detected by positive ones. In this paper we propose the concept of TDDHQ which is aimed at achieving higher quality of testing in TDD by augmenting the standard TDD with suitable test design techniques. To exemplify this concept, we present combining equivalence partitioning test design technique together with the TDD, for the purpose of improving design of test cases. Initial evaluation of this approach showed a noticeable improvement in the quality of test cases created by developers utilising TDDHQ approach.

  • 30.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sajeev, Abdulkadir
    University of New England, Australia.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Redefining the role of testers in organisational transition to agile methodologies2009Ingår i: International Conference on Software, Services & Semantic Technologies (S3T), Sofia, Bulgaria, 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many challenges confront companies when they change their current software development process to an agile development methodology. Those challenges could be rather difficult but one that requires considerable attention is the integration of testing with development. This is because in heavyweight processes, as in the traditional waterfall approach, testing is a phase often conducted by testers as part of a quality assurance team towards the end of the development cycle whereas in the agile methodology testing is part of a continuous development activity with no specific “tester” role defined. In this paper we consider several options for testers when an organisation transit to agile methodology, and propose a new project mentor role for them. This role aims to utilize the knowledge that testers already have in both the business domain and the development technology together with their expertise in quality practices. This role will enhance the stature of testers as well as enable the company to effectively deploy the testers in the new environment. Motivations and benefits for this role are presented in this paper together with our plan for evaluation of this proposal.

  • 31.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Shukla, Rakesh
    Infosys Ltd., India.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Systems.
    Industrial Study on Test Driven Development: Challenges and Experience2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Conducting empirical studies in industry always presents a major challenge for many researchers. Being a graduate student does not make things any easier. Often due to the lack of experience, credibility or just very limited networking, graduate students do not receive many opportunities to directly collaborate with industry and experiment their theoretical models in a realistic environment. On the other hand, empirical research conducted in an academic settings is often criticised for using students as subjects and working with a small sample size, thus creating major validity threat of the published results. In this paper we are presenting an experience report from an industrial empirical study conducted at Infosys Ltd., India with the support of their global internship program for graduate students, InStep. Focus of the paper is to present several challenges arisen before, during, and after the study, requiring an immediate attention in order to have a successful experiment completion. We also discuss and elaborate the data analysis results and its implication to our current research activities.

  • 32.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Shukla, Rakesh
    Infosys Ltd., India.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Effects of Negative Testing on TDD: An Industrial Experiment2013Ingår i: Agile Processes in Software Engineering and Extreme Programming: 14th International Conference, XP 2013, Vienna, Austria, June 3-7, 2013. Proceedings, Springer , 2013, s. 91-105Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In our recent academic experiments, an existence of positive test bias, that is lack of negative test cases, was identified when a test driven development approach was used. At the same time, when defect detecting ability of individual test cases was calculated, it was noted that the probability of a negative test case to detect a defect was substantially higher than that of a positive test case. The goal of this study is to investigate the existence of positive test bias in test driven development within an industrial context, and measure defect detecting ability of both positive and negative test cases. An industrial experiment was conducted at Infosys Ltd. India, whose employees voluntarily signed up to participate in the study and were randomly assigned to groups utilizing test driven development, test driven development with negative testing, and test last development. Source code and test cases created by each participant during the study were collected and analysed. The collected data indicate a statistically significant difference between the number of positive and negative test cases created by industrial participants, confirming the existence of positive test bias. The difference in defect detecting ability of positive and negative test cases is also statistically significant. As a result, similarly to our previous academic study, 29% of all test cases were negative, contributing by revealing as much as 71% of all the defects found by all test cases. With this industrial experiment, we confirmed the existence of a positive test bias in an industrial context, as well as significantly higher defect detecting ability of negative test cases.

  • 33.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    An Industrial Survey on Contemporary Aspects of Software Testing2010Ingår i: ICST 2010 - 3rd International Conference on Software Testing, Verification and Validation, Paris, France, 2010, s. 393-401Konferensbidrag (Refereegranskat)
    Abstract [en]

    Software testing is a major source of expense in software projects and a proper testing process is a critical ingredient in the cost-efficient development of high-quality software. Contemporary aspects, such as the introduction of a more lightweight process, trends towards distributed development, and the rapid increase of software in embedded and safety-critical systems, challenge the testing process in unexpected manners. To our knowledge, there are very few studies focusing on these aspects in relation to testing as perceived by different contributors in the software development process. This paper qualitatively and quantitatively analyses data from an industrial questionnaire survey, with a focus on current practices and preferences on contemporary aspects of software testing. Specifically, the analysis focuses on perceptions of the software testing process in different categories of respondents. Categorization of respondents is based on safety-criticality, agility, distribution of development, and application domain. While confirming some of the commonly acknowledged facts, our findings also reveal notable discrepancies between preferred and actual testing practices. We believe continued research efforts are essential to provide guidelines in the adaptation of the testing process to take care of these discrepancies, thus improving the quality and efficiency of the software development.

  • 34.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Factors Limiting Industrial Adoption of Test Driven Development: A Systematic Review2011Ingår i: 4th IEEE International Conference on Software Testing, Verification, and Validation, ICST 2011; Berlin; 21 March 2011 through 25 March 2011, 2011, s. 337-346Konferensbidrag (Refereegranskat)
    Abstract [en]

    Test driven development (TDD) is one of the basic practices of agile software development and both academia and practitioners claim that TDD, to a certain extent, improves the quality of the code produced by developers. However, recent results suggest that this practice is not followed to the extent preferred by industry. In order to pinpoint specific obstacles limiting its industrial adoption we have conducted a systematic literature review on empirical studies explicitly focusing on TDD as well as indirectly addressing TDD. Our review has identified seven limiting factors viz., increased development time, insufficient TDD experience/knowledge, lack of upfront design, domain and tool specific issues, lack of developer skill in writing test cases, insufficient adherence to TDD protocol, and legacy code. The results of this study is of special importance to the testing community, since it outlines the direction for further detailed scientific investigations as well as highlights the requirement of guidelines to overcome these limiting factors for successful industrial adoption of TDD.

  • 35.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Impact of Test Design Technique Knowledge on Test Driven Development: A Controlled Experiment2012Ingår i: Lecture Notes in Business Information Processing, vol. 111 LNBIP, Springer, 2012, s. 138-152Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Agile development approaches are increasingly being followed and favored by the industry. Test Driven Development (TDD) is a key agile practice and recent research results suggest that the successful adoption of TDD depends on different limiting factors, one of them being insufficient developer testing skills. The goal of this paper is to investigate if developers who are educated on general testing knowledge will be able to utilize TDD more efectively. We conducted a controlled experiment with master students during the course on Software Verification & Validation (V&V) where source code and test cases created by each participant during the labs as well as their answers on a survey questionnaire were collected and analyzed. Descriptive statistics indicate improvements in statement coverage. However, no statistically significant differences could be established between the pre- and post-course groups of students. By qualitative analysis of students’ tests, we noticed a lack of test cases for non-stated requirements ("negative" tests) resulting in a non-detection of bugs. Students did show preference towards TDD in surveys. Although further research is required to fully establish this, we believe that identifying specific testing knowledge which is complementary to the testing skills of a new TDD developer would enable developers to perform their tasks in a more eficient manner.

  • 36.
    Causevic, Adnan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Test Case Quality in Test Driven Development: A Study Design and a Pilot Experiment2012Ingår i: EASE 2012, Proceedings, 2012, s. 223-227Konferensbidrag (Refereegranskat)
    Abstract [en]

    Background: Test driven development, as a side-effect of developing software, will produce a set of accompanied test cases which can protect implemented features during code refactoring. However, recent research results point out that successful adoption of test driven development might be limited by the testing skills of developers using it. Aim: Main goal of this paper is to investigate if there is a difference between the quality of test cases created while using test-first and test-last approaches. Additional goal of this paper is to measure the code quality produced using test-first and test-last approaches. Method: A pilot study was conducted during the master level course on Software Verification & Validation at Mälardalen University. Students were working individually on the problem implementation by being randomly assigned to a test-first or a test-last (control) group. Source code and test cases created by each participant during the study, as well as their answers on a survey questionnaire after the study, were collected and analysed. The quality of the test cases is analysed from three perspectives: (i) code coverage, (ii) mutation score and (iii) the total number of failing assertions. Results: The total number of test cases with failing assertions (test cases revealing an error in the code) was nearly the same for both test-first and test-last groups. This can be interpreted as "test cases created by test-first developers were as good as (or as bad as) test cases created by test-last developers". On the contrary, solutions created by test-first developers had, on average, 27% less failing assertions when compared to solutions created by the test-last group. Conclusions: Though the study provided some interesting observations, it needs to be conducted as a fully controlled experiment with a higher number of participants in order to validate statistical significance of the presented results.

  • 37.
    Chandran, Senthil Kumar
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dimov, Aleksandar
    University of Sofia.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Modeling uncertainties in the estimation of software reliability: A pragmatic approach2010Ingår i: Proceedings - 2010 Fourth International Conference on Secure Software Integration and Reliability Improvement, SSIRI 2010, IEEE , 2010, s. 227-236Konferensbidrag (Refereegranskat)
    Abstract [en]

    The increasing usage of computer based systems for safety critical operations in applications such as nuclear, space, and automotive systems demands a systematic way of estimating software reliability. The high reliability requirements of safety critical software systems make this task imperative as well. Due to the specifics of software systems and the lack of any universally accepted models it is very difficult to predict the true reliability value of the system. Unfortunately none of the existing software reliability models neither acknowledge nor address this fact. There exist multiple uncertainty factors that influence reliability estimation of safety critical software systems. In this paper, we first define the scope of the important factors in the reliability models and describe a new approach to obtain a realistic estimate for system reliability. For this purpose, we consider different kinds of reliability models also taking into account the system architecture. The influence of uncertainty factors in the models is analyzed to obtain uncertainty bounds. They show an interval, where the true reliability should lie within it. This way system architects may use a so-called worst-case reliability estimation, given by the lower interval bound, for system analysis. We also demonstrate our proposed approach with real data taken from safety-critical applications.

  • 38.
    Chandran, Senthil Kumar
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Pillay, Radhamani
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Efficient scheduling with adaptive fault tolerance in heterogeneous multiprocessor systems2010Ingår i: International Conference on Computer and Electrical Engineering (ICCEE), Chengdu, China, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Heterogeneous multiprocessor systems are becoming more common and scheduling real-time tasks on them is an extremely challenging research problem. While the stringent functional and timing requirements are to be met, this problem becomes even more difficult in dynamic environments, for example, caused by processor failures. Furthermore, in safety critical applications having tasks with mixed criticality levels, guaranteeing adaptive fault tolerance to meet the reliability requirements adds another complex dimension. The key contribution of our research is a framework for task allocation and scheduling in the above context, which has a generic task model enabling task-level redundancy, a range of reconfiguration/task migration options during processor failures and definition of a set of performance metrics. We have addressed the issues of both timeliness and reliability under three different allocation strategies for a multiprocessor system with the feasibility check being performed using the well-known Rate Monotonic (RM) schedulability test. The algorithm presented in this paper, ensures that all required deadlines are met with efficient processor utilization under normal conditions and guarantees essential operations even during processor failures. In real-time multiprocessor systems used in safety critical applications, the proposed approach is expected to provide better utilization of resources and guarantees with respect to the system reliability. We demonstrate as well as evaluate the performance of our approach by simulation studies on task scheduling in heterogeneous multiprocessor environments.

  • 39.
    Chandran, Senthil Kumar
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards a reliable communication network for International Monitoring System2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Building a secure and reliable network system especially for safety critical applications is an extremely challenging task even when the scale of the application or physical boundaries of the system are small and well-defined. The complex issues in network communications, security and data quality apart from the high reliability requirements pose difficult scientific problems one has to tackle with. In the context of the international monitoring system, these challenges become much more daunting due to heterogeneous network topologies, mixing of private networks and internet as well as the enormity of geographical coverage. This paper attempts to provide an overview of the various approaches followed internationally in dealing with reliable network communications. One of methods highlighted in this paper for a secure communication for the International Monitoring System is the usage of Virtual Private Networks (VPN) in the identified sensor locations to communicate data to desired local access server locations through unsecured public networks. This setup could be for nearby local stations within a specified radius. The data is routed through a tunnel to local servers in the VPN using protocols such as IPSEC, PPTP etc. Multi-homed network that provides redundant links are cost effective and are proposed as means to ensure high reliability and end-to-end availability between the VPN servers to the centralized system located at Vienna. This paper also compares various communication technologies and dependability strategies available and recommends suitable combinations that overcomes the challenges such as malicious attacks, various failure modes, dynamic changing of the routing table to address dead links etc., to preserve data integrity and provide highly reliable information to the end users.

  • 40.
    Davis, Rob
    et al.
    University of York, UK.
    Gettings, Oliver
    University of York, UK.
    Thekkilakattil, Abhilash
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    What is the Exact Speedup Factor for Fixed Priority Pre-emptive versus Fixed Priority Non-pre-emptive Scheduling?2015Ingår i: Proceedings of the 6th Real-Time Scheduling Open Problems Seminar (RTSOPS): held in conjunction with the 27th Euromicro Conference on Real-Time Systems (ECRTS), Lund, Sweden, 2015, s. 23-24Konferensbidrag (Refereegranskat)
  • 41.
    Davis, Rob
    et al.
    University of York, York, UK.
    Thekilakkattil, Abhilash
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Gettings, Oliver
    University of York, York, UK.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Chen, Jian-Jia
    Technische Universität, Dortmund, Germany..
    Exact Speedup Factors and Sub-Optimality for Non-Preemptive Scheduling2018Ingår i: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, s. 208-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fixed priority scheduling is used in many real-time systems; however, both preemptive and non-preemptive variants (FP-P and FP-NP) are known to be sub-optimal when compared to an optimal uniprocessor scheduling algorithm such as preemptive Earliest Deadline First (EDF-P). In this paper, we investigate the sub-optimality of xed priority non-preemptive scheduling. Speci cally, we derive the exact processor speed-up factor required to guarantee the feasibility under FP-NP (i.e. schedulablability assuming an optimal priority assignment) of any task set that is feasible under EDF-P. As a consequence of this work, we also derive a lower bound on the sub-optimality of non-preemptive EDF (EDF-NP). As this lower bound matches a recently published upper bound for the same quantity, it closes the exact sub-optimality for EDF-NP. It is known that neither preemptive, nor non-preemptive xed priority scheduling dominates the other, in other words, there are task sets that are feasible on a processor of unit speed under FP-P that are not feasible under FP-NP and vice-versa. Hence comparing these two algorithms, there are non-trivial speedup factors in both directions. We derive the exact speed-up factor required to guarantee the FP-NP feasibility of any FP-P feasible task set. Further, we derive the exact speed-up factor required to guarantee FP-P feasibility of any constrained-deadline FP-NP feasible task set.

  • 42.
    Davis, Rob
    et al.
    University of York, UK.
    Thekkilakattil, Abhilash
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Gettings, Oliver
    University of York, UK.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Quantifying the Exact Sub-Optimality of Non-Preemptive Scheduling2015Ingår i: Proceedings - Real-Time Systems Symposium, 2015, s. 96-106Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fixed priority scheduling is used in many real-time systems; however, both preemptive and non-preemptive variants (FP-P and FP-NP) are known to be sub-optimal when compared to an optimal uniprocessor scheduling algorithm such as preemptive Earliest Deadline First (EDF-P). In this paper, we investigate the sub-optimality of fixed priority non-preemptive scheduling. Specifically, we derive the exact processor speed-up factor required to guarantee the feasibility under FP-NP (i.e. schedulablability assuming an optimal priority assignment) of any task set that is feasible under EDF-P. As a consequence of this work, we also derive a lower bound on the sub-optimality of non-preemptive EDF (EDF-NP), which since it matches a recently published upper bound gives the exact sub-optimality for EDF-NP. It is known that neither preemptive, nor non-preemptive fixed priority scheduling dominates the other, i.e., there are task sets that are feasible on a processor of unit speed under FP-P that are not feasible under FP-NP and vice-versa. Hence comparing these two algorithms, there are non-trivial speedup factors in both directions. We derive the exact speed-up factor required to guarantee the FP-NP feasibility of any FP-P feasible task set. Further, we derive upper and lower bounds on the speed-up factor required to guarantee FP-P feasibility of any FP-NP feasible task set. Empirical evidence suggests that the lower bound may be tight, and hence equate to the exact speed-up factor in this case.

  • 43.
    Desai, Nitin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Safety of fog-based industrial automation systems2019Ingår i: IoT-Fog 2019 - Proceedings of the 2019 Workshop on Fog Computing and the IoT, Association for Computing Machinery, Inc , 2019, s. 6-10Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Fog computing paradigm employing multiple technologies is expected to play a key role in a multitude of industrial applications by fulfilling futuristic requirements such as flexible and enhanced computing, storage, and networking capability closer to the field devices. While performance aspects of the Fog paradigm has been the central focus of researchers, safety aspects have not received enough attention so far. In this paper, we identify various safety challenges related to the Fog paradigm and provide specific safety design aspects as a step towards enhancing safety in industrial automation scenarios. We contextualize these ideas by invoking a distributed mobile robots use-case that can benefit from the use of the Fog paradigm.

  • 44.
    Dimov, Aleksandar
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik. Sofia University St. Kliment Ohridski.
    Chandran, Senthil Kumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    How do we collect data for software reliability estimation?2010Ingår i: ACM International Conference Proceeding Series Volume 471, 2010, 2010, s. 155-160Konferensbidrag (Refereegranskat)
    Abstract [en]

    Together with increase of the influence of software systems in all aspects of everyday life there is also a need to focus on their non-functional characteristics. Reliability is one important software quality characteristic, which is defined as continuity of correct service. Reasoning and modeling are necessary in order to achieve desired levels of reliability both during design and usage of software systems. There exist different techniques for gathering of data for software reliability estimation and the aim of this paper is to make a good overview of them. As software testing is the biggest and most widely applied technique we also make a study of current state of the art in application of different testing methods for collection of data to be used for reliability estimation.

  • 45.
    Dimov, Aleksandar
    et al.
    University of Sofia.
    Chandran, Senthil Kumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nasir, A.
    Lahore University of Management Sciences.
    Azam, N.
    Lahore University of Management Sciences.
    Mutation testing framework for software reliability model analysis and reliability estimation2010Ingår i: Central and Eastern European Software Engineering Conference (CEE-SECR), 2010, s. 163-169Konferensbidrag (Refereegranskat)
    Abstract [en]

    After several years of research, even today estimation of software reliability is extremely challenging. The undeterministic nature of the factors that contribute to the reliability estimation has led to the development of numerous statistical models for this purpose. One of the important factors that contribute to software reliability is testing. The aim of this paper is to use mutation testing for estimating the „true” reliability of a system and provide a framework for estimation of uncertainty bounds associated with testing and a measure for factors such as test coverage, time between failures and code coverage that contribute to the estimation of reliability and use mutation testing as a tool to create a software failure dataset. The approach is experimented with an open source search tool.

  • 46.
    Dimov, Aleksandar
    et al.
    University of Sofia.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Fuzzy reliability model for component-based software systems2010Ingår i: Proceedings - 36th EUROMICRO Conference on Software Engineering and Advanced Applications, SEAA 2010, 2010, s. 39-46Konferensbidrag (Refereegranskat)
    Abstract [en]

    Component-based software engineering has been projected off-late as an appropriate paradigm for embedded systems development. However this becomes feasible only if the dependability attributes, such as reliability, of embedded systems can be properly estimated and guaranteed using appropriate models. Another recent trend is the prevalence of Architectural modeling of software systems due to the advantages such as composability reasoning and analysis of system behavior as well as the flexibility and reusability of models. However, there is little support for the systematic modeling of reliability in architectural description languages at a given abstraction level. Another major issue is the uncertainty of the reliability parameters associated with the traditional testing-based approaches for particular architectural entities (e.g. components and/or connectors). In this context, we propose a new approach for the reliability estimation of component-based software systems, which steps on an architectural model of the system using Generalized Nets. This notation is a generalization of Petri nets and is an all-purpose formal modeling technique for the description of parallel phenomena. For the reliability description, we apply possibility theory, which has the potential to solve the uncertainty aspect. This is based on fuzzy sets and describes reliability properties of software components in systems architecture with fuzzy measures.

  • 47.
    Dobrin, Radu
    et al.
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Aysan, Hüseyin
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Punnekkat, Sasikumar
    Mälardalens högskola, Institutionen för innovation, design och produktutveckling.
    Maximizing the Fault Tolerance Capability of Fixed Priority Schedules2008Ingår i: RTCSA 2008: 14TH IEEE INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS - PROCEEDINGS, 2008, s. 337-346Konferensbidrag (Refereegranskat)
    Abstract [en]

    Real-time systems typically have to satisfy complex requirements, mapped to the task attributes, eventually guaranteed by the underlying scheduler. These systems consist of a mix of hard and soft tasks with varying criticality as well as associated fault tolerance requirements. Additionally, the relative criticality of tasks could undergo changes during the evolution of the system. Time redundancy techniques are often preferred in many embedded applications and, hence, it is extremely important to devise appropriate methodologies for scheduling real-time tasks under error assumptions. In this paper, we propose a methodology to provide a priori guarantees in fixed priority scheduling (FPS) such that the system will be able to tolerate one error per every critical task instance. We do so by using Integer Linear Programming (ILP) to derive task attributes that guarantee re-execution of every critical task instance before its deadline, while keeping the associated costs minimized. We illustrate the effectiveness of our approach, in comparison with fault tolerant (FT) adaptations of the well-known rate monotonic (RM), by simulations.

  • 48.
    Dobrin, Radu
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Desai, Nitin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    On Fault-tolerant Scheduling of Time Sensitive Networks2019Ingår i: 4th International Workshop on Security and Dependability of Critical Embedded Real-Time Systems CERTS 2019, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Time sensitive networking (TSN) is gaining attention in industrial automation networks since it brings essential real-time capabilities at the data link layer. Though it can provide deterministic latency under error free conditions, TSN still largely depends on space redundancy for improved reliability.In many scenarios, time redundancy could be an adequate as well as cost efficient alternative. Time redundancy in turn will have implications due to the need for over-provisions needed for timeliness guarantees. In this paper, we discuss how to embed fault-tolerance capability into TSN schedules and describe our approach using a simple example.

  • 49.
    Eldh, Sigrid
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Brandt, Joachim
    Ericsson Ltd.
    Street, Mark
    Ericsson Ltd.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Fully Automated Test Management for Large Complex Systems2010Ingår i: ICST 2010 - 3rd International Conference on Software Testing, Verification and Validation, Paris, 2010, s. 412-420Konferensbidrag (Refereegranskat)
    Abstract [en]

    Development of large and complex software intensive systems with continuous builds typically generates large volumes of information with complex patterns and relations. Systematic and automated approaches are needed for efficient handling of such large quantities of data in a comprehensible way. In this paper we present an approach and tool enabling autonomous behavior in an automated test management tool to gain efficiency in concurrent software development and test. By capturing the required quality criteria in the test specifications and automating the test execution, test management can potentially be performed to a great extent without manual intervention. This work contributes towards a more autonomous behavior within a distributed remote test strategy based on metrics for decision making in automated testing. These metrics optimize management of fault corrections and retest, giving consideration to the impact of the identified weaknesses, such as fault-prone areas in software.

  • 50.
    Eldh, Sigrid
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Analysis of Mistakes as a Method to Improve Test Case Design2011Ingår i: International Conference on Software Testing, Verification and Validation(ICST), Berlin, 2011, s. 70-79Konferensbidrag (Refereegranskat)
    Abstract [en]

    Test Design - how test specifications and test cases are created - inherently determines the success of testing. However, test design techniques are not always properly applied, leading to poor testing. We have developed an analysis method based on identifying mistakes made when designing the test cases. Using an extended test case template and an expert review, the method provides a systematic categorization of mistakes in the test design. The two main classes of identified mistakes are (1) lack of comprehension (of the employed test design technique, target of test etc.) and (2) incomplete test case construction (due to lack of detail, missing clean-up, ambiguities, etc.). The detailed categorization of mistakes provides a basis for improvement of the Test Case Design, resulting in better tests. In developing our method we have investigated over 700 test cases created by novice testers. In a comparison with industrial test cases we could confirm that many of our mistake categories remain relevant also in an industrial context. Our contribution is a new method to improve the effectiveness of test case construction through proper application of test design techniques, leading to an improved coverage without loss of efficiency.

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