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  • 151.
    Lo Bello, Lucia
    et al.
    University of Catani.
    Kaczynski, Giordano A.
    University of Catania.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Towards a robust real-time wireless link in a land monitoring application2006Inngår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA, 2006, s. 449-452Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses on-going work on providing a model of a robust real-time wireless link intended to be used to connect a mobile platform to a ground station in a land monitoring system. This work is part of a project where the mobile platform is an Unmanned Aerial Vehicle (UAV), equipped with embedded devices which acquire and process sensor data to be sent to the ground station. Firstly, a temporal model of the communications link relying on radio modems is developed. Secondly, measurements have been made in order to determine packet loss probability. These two results are currently used to provide a robust real-time model of the wireless communications link.

  • 152. Lo Bello, Lucia
    et al.
    Kaczynski, Giordano A.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Sorbello, Gino
    Sgro, Francesco
    Mirabella, Orazio
    An approach to support UAV to ground station real-time communications in a land monitoring system2006Konferansepaper (Fagfellevurdert)
  • 153.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bohlin, Markus
    Swedish Institute of Computer Science, Kista, Sweden).
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kreuger, Per
    Swedish Institute of Computer Science, Kista, Sweden).
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Approximate Timing Analysis of Complex Legacy Real-Time Systems using Simulation Optimization2008Inngår i: Proceedings of the Work-In-Progress (WIP) track of the 29th IEEE Real-Time Systems Symposium (RTSS), Barcelona, Spain, 2008Konferansepaper (Fagfellevurdert)
  • 154.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Cicchetti, Antonio
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bygde, Stefan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Transformational Specification of Complex Legacy Real-Time Systems via Semantic Anchoring2009Inngår i: 2nd IEEE International Workshop on Component-Based Design of Resource-Constrained Systems (CORCS 2009) @ COMPSAC, 2009, s. 1183-1188Konferansepaper (Fagfellevurdert)
    Abstract [en]

    RTSSim is a framework for simulating models extracted from complex legacy real-time systems which are task-oriented, run on a single processor and are developed in C. Such RTSSim models describe functional and temporal behavior as well as the resource usage of the system. However, the semantics specification of RTSSim models remains a challenging problem indeed, especially with tractable complexity to obtain a formal model which can be analyzed for instance by a model checking tool. In this paper, we present an approach towards using semantic anchoring for the transformational specification of RTSSim models, by relying on units with well-defined operational semantics and tool support. Specifically, Timed Automata with Tasks (TAT) in TIMES is chosen as the semantic unit with the purpose of anchoring different behavioral concerns of RTSSim models in all aspects. In this respect, model transformations are conducted at the meta-model level allowing the original operational semantics of RTSSim models to be preserved, while at the same time it can be presented in TIMES models in terms of a network of TAT.

  • 155.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    A statistical approach to simulation model validation in response-time analysis of complex real-time embedded systems2011Inngår i: Proceedings of the ACM Symposium on Applied Computing 2011, 2011, s. 711-716Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As simulation-based analysis methods make few restrictions on the system design and scale to very large and complex systems, they are widely used in, e.g., timing analysis of complex real-time embedded systems (CRTES) in industrial circles. However, before such methods are used, the analysis simulation models have to be validated in order to assess if they represent the actual system or not, which also matters to the confidence in the simulation results. This paper presents a statistical approach to validation of temporal simulation models extracted from CRTES, by introducing existing mature statistical hypothesis tests to the context. Moreover, our evaluation using simulation models depicting a fictive but representative industrial robotic control system indicates that the proposed method can successfully identify temporal differences between different simulation models, hence it has the potential to be considered as an effective simulation model validation technique. © 2011 ACM.

  • 156.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Statistical Approach for Validation of Task Simulation Models with Intricate Temporal Execution Dependencies2010Inngår i: Proceedings of the Work-In-Progress (WIP) track of 16th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS2010), 2010Konferansepaper (Fagfellevurdert)
  • 157.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    On Validation of Simulation Models in Timing Analysis of Complex Real-Time Embedded Systems2010Inngår i: The 15th IEEE International Conference on Emerging Technologies and Factory Automation (EFTA'10), Work-In-Progress (WIP) session., Bilbao, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we present work toward validating simulation models extracted from complex real-time embedded systems, from the perspective of response time and execution time of adhering tasks, by using the non-parametric two-sample Kolmogorov-Smirnov test. Moreover, we introduce a method of reducing the number of samples used in the analysis, while keeping the accuracy of results. The evaluation using a fictive but representative system model inspired by a real robotic control system with a set of change scenarios, shows a promising result: the proposed algorithm has the potential of assessing whether the extracted simulation model is a sufficiently accurate approximation of the target system.

  • 158.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    An Evaluation Framework for Complex Industrial Real-Time Embedded Systems2012Rapport (Annet vitenskapelig)
    Abstract [en]

    In this technical report, we introduce an evaluation framework which are centering around four base models, inspired by an industrial robotic control application. Specifically, such evaluation models are quite complicated from a task execution and temporal dependencies perspective, making difficult to perform the corresponding timing analysis.

  • 159.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    On Using Extreme Value Theory in Response-Time Analysis of Priority-Driven Periodic Real-Time Systems2010Inngår i: The 31st IEEE Real-Time Systems Symposium (RTSS'10), Work-In-Progress (WIP) session, San Diego, CA, USA, 2010Konferansepaper (Fagfellevurdert)
  • 160.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    Cucu-Grosjean, Liliana
    INRIA Nancy-Grand Est, Nancy, France.
    A New Way about using Statistical Analysis of Worst-Case Execution Times2011Inngår i: ACM SIGBED Review, ISSN 1551-3688, Vol. 8, nr 3, s. 11-14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we revisit the problem of using Extreme Value Theory (EVT) in the Worst-Case Execution Time (WCET) analysis of the programs running on a single processor. Our proposed statistical WCET analysis method consists of a novel sampling mechanism tackling with some problems that hindered the application of using EVT in the context, and a statistical inference about computation of a WCET estimate of the target program. To be specific, the presented sampling mechanism takes analysis samples from the target program based around end-to-end measurements. Next, the statistical inference using EVT together with other statistical techniques, analyzes such timing traces which contain the execution time data of the program, to compute a WCET estimate with a certain predictable probability of being exceeded.

  • 161.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    Cucu-Grosjean, Liliana
    INRIA Nancy-Grand Est.
    A statistical response-time analysis of complex real-time embedded systems by using timing traces2011Inngår i: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings, 2011, s. 43-46Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time embedded systems are becoming ever more complex, and we are reaching the stage where even if static Response-Time Analysis (RTA) was feasible from a cost and technical perspective, the results are overly pessimistic making them less useful to the practitioner. When combined with the fact that most timing analysis tends to be statistical in nature, this suggests there should be a move towardstatistical RTA. However, to make such analysis useful, it is imperative that we have evidence that the statistical RTA and the information analyzed is sufficiently accurate. In this paper we present and validatea technique for statistical RTA that can cope with systems that are complex from both a size and tasks' dependencies perspective. This claim is backed up by our evaluation using information from realindustrial control systems.

  • 162.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Cucu-Grosjean, Liliana
    INRIA Nancy-Grand Est.
    A statistical response-time analysis of real-time embedded systems2012Inngår i: Proceedings - Real-Time Systems Symposium, 2012, 2012, s. 351-362Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time embedded systems are becoming ever more complex. We are reaching the stage where even if static Response-Time Analysis (RTA) was feasible from a cost and technical perspective, the results of such an analysis are overly pessimistic. This makes them less useful to the practitioner. In addition, the temporal validation and verification of such systems in some applications, e.g., aeronautics, requires the probability of obtaining a worst-case response time larger than a given value in order to support dependable system functions. All these facts advocate moving toward statistical RTA, which instead of calculating absolute worst-case timing guarantees, computes a probabilistic worst-case response time estimate. The contribution of this paper is to present and evaluate such a statistical RTA technique which uses a black box view of the systems under analysis, by not requiring estimates of parameters such as worst-case execution times of tasks. Furthermore, our analysis is applicable to real systems that are complex, e.g., from a task dependencies perspective.

  • 163.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    Cucu-Grosjean, Liliana
    INRIA Nancy-Grand Est, Nancy, France.
    A Trace-Based Statistical Worst-Case Execution Time Analysis of Component-Based Real-Time Embedded Systems2011Inngår i: 2011 IEEE 16TH CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA) / [ed] Mammeri, Z., New York: IEEE , 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the tool support for a framework for performing statistical WCET analysis of real-time embedded systems by using bootstrapping sampling and Extreme Value Theory (EVT). To be specific, bootstrapping sampling is used to generate timing traces, which not only fulfill the requirements given by statistics and probability theory, but also are robust to use in the context of estimating the WCET of programs. Next, our proposed statistical inference uses EVT to analyze such timing traces, and computes a WCET estimate of the target program, pertaining to a given predictable probability. The evaluation results show that our proposed method could have the potential of being able to provide a tighter upper bound on the WCET estimate of the programs under analysis, when compared to the estimates given by the referenced WCET analysis methods.

  • 164.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Assessment of trace-differences in timing analysis for Complex Real-Time Embedded Systems2011Inngår i: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings, 2011, s. 284-293Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we look at identifying temporal differences between different versions of Complex Real-Time Embedded Systems (CRTES) by using timing traces representing response times and executiontimes of tasks. In particular, we are interested in being able to reason about whether a particular change to CRTES will impact on their temporal performance, which is difficult to answer due to the complicatedtiming behavior such CRTES have. To be specific, we first propose a sampling mechanism to eliminate dependencies existing in tasks' response time and execution time data in the traces taken from CRTES, which makes any statistical inference in probability theory and statistics realistic. Next, we use a mature statistical method, i.e., the non-parametric two-sample Kolmogorov-Smirnov test, to assess the possible temporal differences between different versions of CRTES by using timing traces. Moreover, we introduce a method of reducing the number of samples used in the analysis, while keeping the accuracy ofanalysis results. This is not trivial, as collecting a large amount of samples in terms of executing real systems is often costly. Our evaluation using simulation models describing an industrial robotic controlsystem with complicated tasks' timing behavior, indicates that the proposed method can successfully identify temporal differences between different versions of CRTES, if there is any. Furthermore, our proposed method outperforms the other statistical methods, e.g., bootstrap and permutation tests, that are often widely used in contexts, in terms of bearing on the accuracy of results when other methods have failed.

  • 165.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Timing Analyzing for Systems with Execution Dependencies between Tasks2010Inngår i: Proceedings of the ACM Symposium on Applied Computing 201, 2010, s. 357-358Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, a novel approach to timing analysis of complex real-time systems with intricate execution dependencies between tasks, such as asynchronous message-passing and globally shared state variables, is presented. By applying the method to a model taken from a real robotic control system, we show the benefit, in terms of reduced pessimism, when compared to a combination of standard static WCET analysis and Response-Time Analysis.

  • 166.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bate, Iain
    University of York.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Timing analyzing for systems with task execution dependencies2010Inngår i: Proceedings - International Computer Software and Applications Conference, 2010, s. 515-524Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel approach to timing analysis of complex real-time systems containing data-driven tasks with intricate executiondependencies. Using a system model inspired by industrial control systems, we show how the execution time of tasks can be represented as a mathematical expression instead of a single numeric value. Next, based on this more detailed modeling, we introduce a concrete process of formally obtaining the exact value of both Worst-Case Execution-Time (WCET) and Worst-Case Response-Time (WCRT) of tasks by using upper-part binary search and TIMES (a timed model checker). Finally, in order to show the potential of the proposed approach, we apply it to a model created from a real robotic control system for which the traditional way of obtaining a WCET estimate (through static WCET analysis) on tasks for usage in basic RTA is not appropriate. Our results indicate a significant reduction of pessimism when compared to basic RTA using WCET estimates on tasks given by a basic assumption.

  • 167.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik. INRIA Nancy-Grand Est, Nancy, France.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Cucu-Grosjean, Liliana
    INRIA Nancy-Grand Est, Nancy, France.
    Bate, Iain
    University of York, York, United Kingdom.
    RapidRT: A Tool For Statistical Response-Time Analysis of Complex Industrial Real-Time Embedded Systems2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    RapidRT is a tool for statistical response time analysis of Complex Industrial Real-Time Embedded Systems (CIRTES). A key feature of this tool is that it does not require worst-case execution times of tasks to be known for the computation of a probabilistic task worst-case response time estimate. The presented tool is a step towards bridging the gap between academic research and industrial practice.

  • 168.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    An Approximate Timing Analysis Framework for Complex Real-Time Embedded Systems2010Inngår i: Proceedings - 2010 13th IEEE International Conference on Computational Science and Engineering, CSE 2010, 2010, s. 102-111Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To maintain, analyze and reuse many of today's Complex Real-Time Embedded Systems (CRTES) is very difficult and expensive, which, nevertheless, offers high business value in response to great concern in industry. In such context, not only functional behavior but also non-functional properties of systems have to be assured, i.e., Worst-Case Response Time (WCRT) of tasks has to be known. However, due to high complexity of such systems and the nature of the problem, the exact WCRT of tasks is impossible to find in practice, but may only be bounded. In addition, the existing relatively well developed theories for modeling and analysis of real-time systems are having problems which limit their application in the context. In this paper, we address this challenge by presenting a framework for approximate timing analysis of CRTES, namely AESIR-CORES, which provides a tight interval of WCRT estimates of tasks by the usage of two novel contributions. Our evaluation using three models inspired by two fictive but representative industrial CRTES indicates that AESIR-CORES can either successfully obtain the actual WCRT values, or have the potential to bound the unknown actual WCRT values from a statistical perspective.

  • 169.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    SICS.
    A Statistical Approach to Response-Time Analysis of Complex Real-Time Embedded Systems2010Inngår i: Proceedings of the 16th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2010), 2010, s. 153-160Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents RapidRT, a novel statistical approach to Worst-Case Response-Time (WCRT) analysis targeting complex embedded real-time systems. The proposed algorithm combines Extreme Value Theory (EVT) and other statistical methods in order to produce a probabilistic WCRT estimate. This estimate is calculated using response time data from either Monte Carlo simulations of a detailed model of the system, or from response-time measurements of the real system. The method could be considered as a pragmatic approach intended for complex industrial systems with real-time requirements. The target systems contain tasks with many intricate dependencies in theirtemporal behavior, which violates the assumptions of traditional analytical methods for response time analysis and thereby makes them overly pessimistic. An evaluation ispresented using two simulation models, inspired by an industrial robotic control system, and five other methods as reference.

    Fulltekst (pdf)
    FULLTEXT01
  • 170.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Statistical Approach to Simulation Model Validation in Timing Analysis of Complex Real-Time Embedded Systems2010Inngår i: Proceedings - 16th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2010, Brussels, 2010, s. -160, artikkel-id 5591317Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Simulation-based analysis methods make few restrictions on the system design and scale to very large and complex systems, therefore they are widely used in timing analysis of complex industrial embedded systems. This paper presents a statistical approach to validation of temporal simulation models extracted from complex embedded systems, by introducing existing mature statistical methods to the context. The proposed approach firstly collects sampling distributions of response time and execution time data of tasks in both the modeled system and the model, based on simple random samples (SRS). The second step of the approach is to compare the sampling distributions, regarding interesting timing properties, by using the non-parametric two-sample Kolmogorov-Smirnov test. The evaluation using a fictive system model inspired by a real robotic control system with a set of change scenarios, shows a promising result. The proposed algorithm can identify temporal differences between the target system and its extracted model, i.e., the algorithm can assess whether the extracted model is a sufficiently accurate approximation of the target system.

  • 171.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Statistical-based Response-Time Analysis of Systems with Execution Dependencies between Tasks2009Inngår i: Proceedings of the Work-In-Progress (WIP) track of the 30th IEEE Real-Time Systems Symposium (RTSS'09), Washington, DC, USA, 2009, s. 73-76Konferansepaper (Fagfellevurdert)
  • 172.
    Lu, Yue
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kraft, Johan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Norström, Christer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Statistical-based Response-Time Analysis of Systems with Execution Dependencies between Tasks2010Inngår i: Proceedings of the IEEE International Conference on Engineering of Complex Computer Systems, ICECCS, 2010, s. 169-179Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel statistical-based approach to Worst-Case Response-Time (WCRT) analysis of complex real-time system models. These system models have been tailored to capture intricate execution dependencies between tasks, inspired by real industrial control systems. The proposed WCRT estimation algorithm is based on Extreme Value Theory (EVT) and produces both WCRT estimates together with a probability of being exceeded. By using the tools developed, an evaluation is presented using three different simulation models, and four other methods as reference: Monte Carlo simulation, MABERA, HCRR and traditionalResponse-Time Analysis (basic RTA). Empirical results demonstrate that the benefit of the proposed approach, in terms of 1) reduced pessimism when compared to basic RTA and 2) validated guarantee of never being less than the actual response time values. The proposed approach also needs much fewer simulations compared to other three simulation-based methods.

  • 173. Marau, Ricardo
    et al.
    Almeida, Luis
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Pedreiras, Paulo
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Server-based Switched Ethernet for Real-Time Communications2008Konferansepaper (Fagfellevurdert)
  • 174.
    Marau, Ricardo
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Figueiredo, Nuno
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Santos, Rui
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Pedreiras, Paulo
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Almeida, Luis
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Server-based real-time communications of Switched Ethernet2008Inngår i: Proceedings of the 1st Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'08) in conjunction with the 29th IEEE International Real-Time Systems Symposium (RTSS'08), Barcelona, Spain, 2008Konferansepaper (Fagfellevurdert)
  • 175.
    Martin, G.
    et al.
    Tensilica Inc, Santa Clara, CA, United States.
    Lavagno, L.
    Cadence Berkeley Laboratory, Berkeley, CA, United States.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolin, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Thramboulidis, K.
    University of Patras, Patras, Greece.
    Embedded systems  - An Overview2017Inngår i: Systems, Controls, Embedded Systems, Energy, and Machines, Boca Raton: CRC Press , 2017, s. 16-1-16-1Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Embedded systems span a number of scienti?c and engineering disciplines, which evolve continuously. So does the ?eld of embedded systems. To write on this topic requires a careful choice of the material to be covered, to make a presentation of a reasonable length, and provide a fairly up-to-date material. This chapter focuses on two main areas of embedded systems, which have evolved only in recent years, namely, systems on a chip and networked embedded systems. The section on System-on-Chip surveys a large number of the issues involved in its design. The section on networked embedded systems presents an overview of trends for networking of embedded systems, their design, and their application for in-car controls and automation. This material is preceded by a round up of embedded systems in general, and design trends. 

  • 176.
    Mifdaoui, Ahlem
    et al.
    University of Toulouse, France.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Pedreiras, Paulo
    University of Aveiro, Portugal.
    Almeida, Luis
    University of Porto, Portugal.
    Marau, Ricardo
    University of Porto, Portugal.
    Exploring alternatives to use master/slave full duplex switched Ethernet for avionics embedded applications2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The complexity of distributed real-time systems, including military embedded applications, is increasing due to an increasing number of nodes, their functionality and higher amounts of exchanged data. This higher complexity imposes major development challenges when nonfunctional properties must be enforced. On the other hand, the current military communication networks are a generation old and are no longer effective in facing such increasingly complex requirements. A new communication network, based on Full Duplex Switched Ethernet and Master/slave approach, has been proposed previously. However, this initial approach is not efficient in terms of network bandwidth utilization. In this paper we propose two new alternative approaches that can use the network bandwidth more efficiently. In addition we provide a preliminary qualitative assessment of the three approaches concerning different factors such as performance, scalability, complexity and flexibility.

  • 177.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Adaptive Hierarchical Scheduling Framework: Configuration and Evaluation2013Rapport (Annet vitenskapelig)
    Abstract [en]

    We have introduced an adaptive hierarchicalscheduling framework as a solution for composing dynamic realtime systems, i.e., systems where the CPU demand of its tasks aresubjected to unknown and potentially drastic changes during runtime. The framework consists of a controller which periodicallyadapts the system to the current load situation. In this paper,we unveil and explore the detailed behavior and performanceof such an adaptive framework. Specifically, we investigate thecontroller configurations enabling efficient control parameterswhich maximizes performance, and we evaluate the adaptiveframework against a traditional static one.

    Fulltekst (pdf)
    fulltext
  • 178.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Adaptive Hierarchical Scheduling Framework: Configuration and Evaluation2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have introduced an adaptive hierarchical scheduling framework as a solution for composing dynamic real-time systems, i.e., systems where the CPU demand of its tasks are subjected to unknown and potentially drastic changes during run-time. The framework consists of a controller which periodically adapts the system to the current load situation. In this paper, we unveil and explore the detailed behavior and performance of such an adaptive framework. Specifically, we investigate the controller configurations enabling efficient control parameters which maximizes performance, and we evaluate the adaptive framework against a traditional static one. Furthermore, we demonstrate the results of our investigation using a practical multimedia case study in which we simulate the timing behavior of video decoding tasks running on our proposed framework. In addition, we compare the results of using our framework with the results of using static resource allocation approach.

  • 179.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Exact and Approximate Supply Bound Function for Multiprocessor Periodic Resource Model: Unsynchronized Servers2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Multi Processor Periodic Resource (MPR) model has been proposed for modeling compositional real-time systems which run on a shared multi processor hardware. In this paper we extend the MPR model such that the execution of virtual processors (servers) is not assumed to be synchronized i.e., the servers can have different phases. We believe that relaxing the server synchronization requirement provides greater deal of compatibility for implementing such a compositional method on various hardware platforms. We derive the resource supply bound function of the extended MPR model using an algorithm. Furthermore, we suggest an approach to calculate an approximate supply bound function with lower computational complexity for systems where calculating their supply bound function is computationally expensive.

  • 180.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Implementation of the Multi-Level Adaptive Hierarchical Scheduling Framework2013Inngår i: Proceedings of OSPERT 2013, 2013, s. 11-19Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have presented a multi-level adaptive hierarchical scheduling framework in our previous work. The framework targets compositional real-time systems which are composed of both hard and soft real-time systems. While static CPU portions are reserved for hard real-time components, the CPU portions of soft real-time components are adjusted during run-time. In this paper, we present the implementation details of our framework which is implemented as a Linux kernel loadable module. In addition, we present a case-study to evaluate the performance and the overhead of our framework.

  • 181.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Multi-Level Adaptive Hierarchical Scheduling Framework for Composing Real-Time Systems2013Inngår i: 2013 IEEE 19th International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2013, 2013, s. 320-329Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Processor partitioning and hierarchical scheduling have been widely used for composing hard real-time systems on a shared hardware platform while preserving the timing requirements of the systems. Due to the safety critical nature of the hard real-time systems for deriving the sufficient partition size often conservative analysis is used. Applying the exact same analysis for deriving the partition sizes for soft real-time systems result in unnecessary processors overallocation and consequently waste of the CPU resource. In this paper, to address the problem of composing soft and hard real-time systems on a resource constrained shared hardware, we present a multi-level adaptive hierarchical scheduling framework. In our framework, we adapt the processor partition sizes of soft real-time systems according to their need at each time point by on-line monitoring their processor demand. Furthermore, we implement our adaptive framework in the Linux kernel and show the performance of our framework using a case-study.

  • 182.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Åsberg, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik.
    On Adaptive Hierarchical Scheduling of Real-time Systems Using a Feedback Controller2011Inngår i: 3rd Workshop on Adaptive and Reconfigurable Embedded Systems (APRES'11), 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Hierarchical scheduling provides predictable timing and temporal isolation; two properties desirable in real-time embedded systems. In hierarchically scheduled systems, subsystems should receive a sufficient amount of CPU resources in order to be able to guarantee timing constraints of its internal parts (tasks). In static systems, an exact amount of CPU resource can be allocated to a subsystem. However, in dynamic systems, where execution times of tasks vary considerably during runtime, it is desirable to give a dynamic portion of the CPU given the current load situation. In this paper we present a feedback control approach for adapting the amount of CPU resource that is allocated to subsystems during run-time such that each subsystem receives sufficient resources while keeping the number of deadline violations to a minimum. We also show an example simulation where the controller adapts the budget of a subsystem.

  • 183.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Spampinato, Giacomo
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bandwidth Adaptation in Hierarchical Scheduling Using Fuzzy Controllers2012Inngår i: 7th IEEE International Symposium on Industrial Embedded Systems, SIES 2012 - Conference Proceedings, 2012, s. 148-157Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In our previous work, we have introduced an adaptive hierarchical scheduling framework as a solution for composing dynamic real-time systems, i.e., systems where the CPU demand of their tasks are subjected to unknown and potentially drastic changes during run-time. The framework uses the PI controller which periodically adapts the system to the current load situation. The conventional PI controller despite simplicity and low CPU overhead, provides acceptable performance. However, increasing the pressure on the controller e.g, with an application consisting of multiple tasks with drastically oscillating execution times, degrades the performance of the PI controller. Therefore, in this paper we modify the structure of our adaptive framework by replacing the PI controller with a fuzzy controller to achieve better performance. Furthermore, we conduct a simulation based case study in which we compose dynamic tasks such as video decoder tasks with a set of static tasks into a single system, and we show that the new fuzzy controller outperforms our previous PI controller.

  • 184.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Lelli, Juri
    Scuola Superiore Sant’Anna, Italy.
    Lipari, Giuseppe
    Scuola Superiore Sant’Anna, Italy and LSV - ENS Cachan, France.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Energy-aware Multiprocessor Hierarchical Scheduling of Real-time Systems2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Multiprocessor platforms are becoming increasingly more popular. Providing more computation capacity on a single hardware platform, multiprocessors make it possible to integrate previously federated real-time systems onto a single platform. Multiprocessor hierarchical scheduling techniques provide the ground for composing real-time components, while guaranteeing the timing correctness of the composed system. A considerable deal of compositional real-time systems are embedded systems that operate on battery power. In such systems, reducing the power consumption is of paramount importance to increase the system lifetime. In this paper, we present our idea on reducing the energy consumption when performing hierarchical scheduling on multiprocessors. We formulate the problem, present the model and sketch the outline of the solution. Finally, we present a number of challenges which will be addressed in our work.

  • 185.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Liu, Meng
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik. Embedded Systems.
    Probabilistic Application Interfaces for Hierarchical Scheduling2013Inngår i: IEEE Real-Time Systems Symposium: IEEE Real-Time Systems Symposium Work-in-Progress (WiP) session, Vancouver, Canad, 2013Konferansepaper (Fagfellevurdert)
  • 186.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Åsberg, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Adaptive Hierarchical Scheduling of Real-Time Systems2011Inngår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA, 2011 / [ed] Mammeri, Z., New York: IEEE , 2011, s. 1-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Hierarchical scheduling provides a modular framework for integrating, scheduling and guaranteeing timing constraints of compositional real-time systems. In such a scheduling framework, all modules should receive a sufficient portion of the shared CPU to be able to guarantee timing constraints of their internal parts. In dynamic systems i.e., systems where the execution time of tasks are subjected to sudden and drastic changes during run-time, assigning fixed CPU portions to the modules is conducive to either low CPU utilization or numerous task deadline misses. In this paper, in order to address this problem, we propose an adaptive CPU allocation method which dynamically assigns CPU portions to the modules during run-time based on their current CPU demand. Besides, the presented approach is evaluated using a series of different simulations. In addition, we present a method for scheduling modules in situations when the CPU resource is not sufficient for scheduling all modules. We introduce the notion of module (subsystem) criticality, and in an overload situation we distribute the CPU resource based on the criticality of modules.

  • 187.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ashjaei, Mohammad
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Integrating Response-Time Analyses for Heterogeneous Automotive Networks in MPS-CAN Analyzer2015Inngår i: 6th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems WATERS 2015, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    MPS-CAN analyzer is a research tool that supports the Response Time Analysis (RTA) for Controller Area Network (CAN). It takes into account various queueing policies; buffer limitations in the CAN controllers; and mixed transmission patterns supported by the higher-level protocols. In this paper, we extend the MPS-CAN analyzer to support RTA of heterogeneous automotive networks. Within this context, first we implement RTA for Ethernet Audio/Video Bridging (AVB) messages in a single-switch architecture. We then integrate the analyses for CAN and Ethernet AVB by exploiting the analysis for CAN to Ethernet AVB gateway. With this integration, the MPS-CAN analyzer supports the analysis for heterogeneous messages that traverse through heterogeneous networks consisting of CAN and Ethernet AVB. We also evaluate the newly implemented analyses by conducting an automotive-application case study.

  • 188.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ashjaei, Mohammad
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, J.
    Arcticus Systems AB, Järfälla, Sweden .
    Lundbäck, K-L
    Arcticus Systems AB, Järfälla, Sweden .
    Integrating Response-time Analysis for Heterogeneous Networks with Rubus Analysis Framework: Challenges and Preliminary Solutions2015Inngår i: 2015 IEEE 20th Conference on Emerging Technologies & Factory Automation (ETFA 2015): Proceedings of a meeting held 8-11 September 2015, Luxembourg., 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we discuss the challenges that are faced when the state-of-the-art research results are transferred to a model-based tool chain for the industrial use. These challenges are often overlooked when the research results are implemented in an academic environment. In particular, we discuss various challenges regarding the implementation and integration of the response-time analysis for heterogeneous networks, comprising of CAN and Ethernet AVB, as a plug-in for the Rubus Analysis Framework. Rubus tool suite is used for the model- and component-based development of software for vehicular real-time systems by several international companies. We also discuss preliminary solutions to deal with the challenges.

  • 189.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ashjaei, Mohammad
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, John
    Arcticus Systems AB, Järfälla, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Järfälla, Sweden.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Järfälla, Sweden.
    Modeling of End-to-end Resource Reservations in Component-based Vehicular Embedded Systems2016Inngår i: Software Engineering and Advanced Applications (SEAA), 2016 42th Euromicro Conference on, 2016, s. 283-292Konferansepaper (Fagfellevurdert)
    Abstract [en]

    There is a plethora of models, techniques and toolsthat support model- and component-based software developmentof vehicular distributed embedded systems. However, a large ma-jority of them have a limited or no support to model and specifyend-to-end resource reservations on the software architecturesof these systems. Resource reservations allow flexibility duringthe development and execution of such complex systems withoutjeopardizing their predictable behavior. As a result, severalapplications in the system that share the same hardware platformcan be developed independently. In this paper we identify severalrequirements that any existing component model should fulfill inorder to support the modeling of end-to-end resource reservationson the software architectures of such systems. As a proof ofconcept, we extend the Rubus Component Model (RCM) byfulfilling these requirements. RCM is used for the development ofcontrol functionality in vehicular embedded systems by severalinternational companies. We also provide a technique to extractexecution models from the software architectures of these systemswith resource reservations. In order to show the usability of ourtechnique, we model a vehicular distributed embedded systemwith the extended component model and extract the executionmodel from the software architecture augmented with end-to-endresource reservations.

  • 190.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Applying End-to-end Path Delay Analysis to Multi-rate Automotive Systems Developed using Legacy Tools2015Inngår i: 11th IEEE World Conference on Factory Communication Systems WFCS'15, Institute of Electrical and Electronics Engineers Inc. , 2015, Vol. July, s. Article number 7160585-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The end-to-end path delay analysis is used to predict timing behavior of multi-rate automotive embedded systems. Some of the assumptions used by the existing analysis may not be strictly followed by some legacy tools due to optimizations applied during the development of these systems. As a result, the existing analysis may not be applicable in some cases. In this paper we identify one such case. That is, the case in which all the tasks in a multi-rate task chain have equal priorities despite the fact that they have different periods. Furthermore, the chain contains at least one single-rate sub-chain. We also propose a preliminary solution that makes the existing analysis applicable to this case. However, the proposed solution is pessimistic. Currently, we are working on minimizing the pessimism.

  • 191.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    On timing analysis of component-based vehicular distributed embedded systems at various abstraction levels2016Inngår i: Proceedings - 2016 13th Working IEEE/IFIP Conference on Software Architecture, WICSA 2016, 2016, s. 277-278Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Software development of component-based distributed embedded systems in the vehicle domain can be described at various abstraction levels. One important activity during the development of these systems is to verify their timing requirements by using pre-runtime analysis techniques, e.g., end-to-end timing analysis. There are several models and tools in the vehicle domain that support the timing analysis of these systems. In this paper, we discuss and compare our recent works with the existing techniques that support the end-to-end timing analysis of these systems at each abstraction level.

  • 192.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Järfälla, Sweden .
    Developing predictable vehicular distributed embedded systems on multi-core2016Inngår i: Advances in Intelligent Systems and Computing, Volume 448, 2016, s. 1273-1277Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we address the challenges related to supporting modeland component-based development of predictable software for vehicular distributed embedded systems, utilizing multi-core platforms. We present a research plan for the development of new methods and techniques to deal with these challenges. The techniques will support various aspects such as modeling of the software architecture; supporting multiple criticality levels; verifying predictability of the system using end-to-end timing analysis; code generation; and providing a predictable runtime support on multi-core platforms by virtualizing a certified single-core real-time operating system. As a proof of concept, we will implement the newly developed techniques in a commercial tool chain (Rubus-ICE). The efficacy of the newly developed techniques and the extended tool chain will be demonstrated on the industrial case studies. 

  • 193.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sjödin, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, John
    Arcticus Systems AB, Järfälla, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Järfälla, Sweden.
    Lundbäck, Kurt Lennart
    Arcticus Systems AB, Järfälla, Sweden.
    Modeling of Legacy Distributed Embedded Systems at Vehicle Abstraction Level2016Inngår i: Proceedings - 2016 19th International ACM SIGSOFT Symposium on Component-Based Software Engineering, CBSE 2016, 2016, s. 7-12Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A large majority of existing software development approaches in the vehicle industrial domain have a limited or no modeling support to fully reuse legacy nodes at the highest abstraction, called the vehicle level. In this paper, we introduce a new technique for model-and component-based development of vehicular distributed embedded systems at the vehicle level. The proposed technique supports not only modeling of crude nodes or Electronic Control Units but also modeling of legacy nodes whose software architectures can be partially or completely reused. As a proof of concept, we implement the modeling technique in an industrial model, the Rubus Component Model. In order to show the usability of our approach, we model a vehicular application using the extended component model and its tool suite.

  • 194.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Tomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sjödin, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, John
    Arcticus Systems AB, Järfälla, Sweden.
    Kurt-Lennart, Lundbäck
    Arcticus Systems AB, Järfälla, Sweden.
    Supporting timing analysis of vehicular embedded systems through the refinement of timing constraints2017Inngår i: Software and Systems Modeling, ISSN 1619-1366, E-ISSN 1619-1374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The collective use of several models and tools at various abstraction levels and phases during the development of vehicular distributed embedded systems poses many challenges. Within this context, this paper targets the challenges that are concerned with the unambiguous refinement of timing requirements, constraints and other timing information among various abstraction levels. Such information is required by the end-to-end timing analysis engines to provide pre-run-time verification about the predictability of these systems. The paper proposes an approach to represent and refine such information among various abstraction levels. As a proof of concept, the approach provides a representation of the timing information at the higher levels using the models that are developed with EAST-ADL and Timing Augmented Description Language. The approach then refines the timing information for the lower abstraction levels. The approach exploits the Rubus Component Model at the lower level to represent the timing information that cannot be clearly specified at the higher levels, such as trigger paths in distributed chains. A vehicular-application case study is conducted to show the applicability of the proposed approach.

  • 195.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sjödin, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lundbäck, John
    Arcticus Systems AB, Järfälla, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Järfälla, Sweden.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Järfälla, Sweden.
    End-to-end Timing Analysis of Black-box Models in Legacy Vehicular Distributed Embedded Systems2015Inngår i: 21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications RTCSA'15, 2015, s. 149-158Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A majority of existing techniques and tools, used in the vehicular industry, support the extraction of end-to-end timing models. Such models are used to perform timing analysis of distributed embedded systems at an abstraction level that is close to their implementation. This paper takes a first initiative to provide such a support at a higher level of abstraction. At such a level, the system can be modeled with inter-connected black-box models of nodes whose internal software architectures may not be available. However, most of the design decisions about network communication are available. This represents a typical scenario in the vehicular industry where most of the artifacts are reused from either legacy systems, other projects or previous releases of the vehicle. In this paper we present an approach for the extraction of end-to-end timing models at the highest level of abstraction used in the vehicular domain. Using these models, end-to-end path delay analysis of the systems can be performed at a higher abstraction level and at an early phase during the development. As a proof of concept we implement this technique in an industrial tool suite, Rubus-ICE, that is used for the development of these systems by several international companies. Using the extended tool, we conduct a vehicular-application case study.

  • 196.
    Nemati, Farhang
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    An Investigation of Synchronization under Multiprocessors Hierarchical Scheduling2009Inngår i: Proceedings of the Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    community, considerable work has been done on real-time multiprocessor scheduling algorithms where it is assumed the tasks are independent. However in practice a typical real-time system includes tasks that share resources. On the other hand, synchronization in the multiprocessor context has not received enough attention. In this paper we propose an extension to multiprocessor hierarchical scheduling to support resource sharing. We extend the scheduling framework with an existing synchronization protocol for global scheduling in multi-core systems.

  • 197.
    Nemati, Farhang
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Efficiently Migrating Real-Time Systems to Multi-Cores2009Inngår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09), 2009, s. 1205-1212Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Power consumption and thermal problems limit a further increase of speed in single-core processors. Multi-core architectures have therefore received significant interest. However, a shift to multi-core processors is a big challenge for developers of embedded real-time systems, especially considering existing “legacy” systems which have been developed with uniprocessor assumptions. These systems have been developed and maintained by many developers over many years, and cannot easily be replaced due to the huge development investments they represent. An important issue while migrating to multi-cores is how to distribute tasks among cores to increase performance offered by the multi-core platform. In this paper we propose a partitioning algorithm to efficiently distribute legacy system tasks along with newly developed ones onto different cores. The target of the partitioning is increasing system performance while ensuring correctness.

  • 198.
    Nemati, Farhang
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Independently-Developed Real-Time Systems on Multi-Cores with Shared Resources2011Inngår i: 23rd EUROMICRO Conference on Real-Time Systems (ECRTS'11), Porto, Portugal, 2011, s. 251-261Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose a synchronization protocol for resource sharing among independently-developed real-time systems on multi-coreplatforms. The systems may use different scheduling policies and they may have their own local priority settings. Each system is allocated on a dedicated processor (core). In the proposed synchronization protocol, each system is abstracted by an interface which abstracts the information needed for supporting global resources. The protocol facilitates the composability of various real-time systems with different scheduling and priority settings on a multi-core platform. We have performed experimental evaluations and compared the performance of our proposed protocol (MSOS) against the two existing synchronization protocols MPCP and FMLP. The results show that the new synchronization protocol enables composability without any significant loss of performance. In fact, in most cases the new protocol performs better than at least one of the other two synchronization protocols. Hence, we believe that the proposed protocol is a viable solution for synchronization among independently-developedreal-time systems executing on a multi-core platform.

  • 199.
    Nemati, Farhang
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Independently-developed Systems on Multi-cores with Shared Resources2010Inngår i: 3rd Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'10) in conjunction with the 31th IEEE International Real-Time Systems Symposium (RTSS'10), San Diego, CA, USA, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose a synchronization protocol for resource sharing among independently-developed real-time systems on multi-core platforms. The systems may use different scheduling policies and they may have arbitrary priority settings. When using this synchronization protocol each processor is abstracted by an interface which consists of a set of requirements. A requirement depends only on the worst-case time the processor may wait for resources, i.e., the maximum number of times that the resources can be blocked by other processors. We have derived schedulability conditions for each processor and based on the analysis we extract the interface of the processor. In this paper, we focus on the cases when each system is allocated on a dedicated processor.

  • 200.
    Nemati, Farhang
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Multiprocessor Synchronization and Hierarchical Scheduling2009Inngår i: Proceedings of the First IEEE International Workshop on Real-time Systems on Multicore Platforms: Theory and Practice (XRTS-2009) in conjunction with ICPP'09, 2009, s. 58-64Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Multi-core architectures have received significant interest as thermal and power consumption problems limit further increase of speed in single-cores. In the multi-core research community a considerable amount of work has been done on real-time multi-core scheduling algorithms where it is assumed tasks are independent. However, synchronization of dependent tasks executing on multi-cores has not received as much attention, even though typical real-time systems in practice include tasks that share resources. In this paper we propose a synchronization protocol for hierarchically scheduledmulti-core systems, and we present a comparison between the presented protocol and existing multi-core synchronization protocols. The presented protocol groups dependent tasks that directly or indirectly share mutually exclusive resources into independent components. Within a component dependent tasks use classical uniprocessor synchronization protocols, such as the Stack-based Resource allocation Protocol. The components are then scheduled on the cores by a global scheduler. There are two major approaches for scheduling multicore: partitioned and global scheduling. While most existing multi-core synchronization protocols support only one category, the protocol presented in this paper is developed to handle both scheduling approaches. The presented approach is developed to allow for co-execution of existing legacy real-time applications along with new applications, i.e., a legacy application is put into one or more components preserving its own (original) scheduling and synchronization protocols.

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