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  • 201.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Järfälla, Sweden .
    Developing predictable vehicular distributed embedded systems on multi-core2016In: Advances in Intelligent Systems and Computing, Volume 448, 2016, p. 1273-1277Conference paper (Refereed)
    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. 

  • 202.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    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 Level2016In: Proceedings - 2016 19th International ACM SIGSOFT Symposium on Component-Based Software Engineering, CBSE 2016, 2016, p. 7-12Conference paper (Refereed)
    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.

  • 203.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Tomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    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 constraints2017In: Software and Systems Modeling, ISSN 1619-1366, E-ISSN 1619-1374Article in journal (Refereed)
    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.

  • 204.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    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 Systems2015In: 21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications RTCSA'15, 2015, p. 149-158Conference paper (Refereed)
    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.

  • 205.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    An Investigation of Synchronization under Multiprocessors Hierarchical Scheduling2009In: Proceedings of the Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), 2009Conference paper (Refereed)
    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.

  • 206.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Efficiently Migrating Real-Time Systems to Multi-Cores2009In: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09), 2009, p. 1205-1212Conference paper (Refereed)
    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.

  • 207.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Independently-Developed Real-Time Systems on Multi-Cores with Shared Resources2011In: 23rd EUROMICRO Conference on Real-Time Systems (ECRTS'11), Porto, Portugal, 2011, p. 251-261Conference paper (Refereed)
    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.

  • 208.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Independently-developed Systems on Multi-cores with Shared Resources2010In: 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, 2010Conference paper (Refereed)
    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.

  • 209.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Multiprocessor Synchronization and Hierarchical Scheduling2009In: 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, p. 58-64Conference paper (Refereed)
    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.

  • 210.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sharing Resources among Independently-developed Systems on Multi-cores2011In: ACM SIGBED Review, ISSN 1551-3688, Vol. 8, no 1, p. 46-53Article in journal (Refereed)
    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.

  • 211.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    J. Bril, Reinder
    Eindhoven University of Technology.
    Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling2009In: Proceedings of the Work-In-Progress (WIP) session of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09), 2009Conference paper (Refereed)
    Abstract [en]

    In the multi-core and multiprocessor domain, there has been considerable work done on scheduling techniques assuming that real-time tasks are independent. In practice a typical real-time system usually share logical resources among tasks. However, synchronization in the multiprocessor area has not received enough attention. In this paper we investigate the possibilities of extending multiprocessor hierarchical scheduling to support an existing synchronization protocol (FMLP) in multiprocessor systems. We discuss problems regarding implementation of the synchronization protocol under the multiprocessor hierarchical scheduling.

  • 212.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Towards Resource Sharing by Message Passing among Real-Time Components on Multi-cores2011In: 2011 IEEE 16th International Conference on Emerging Technology and Factory Automation, ETFA 2011,Toulouse, France; 5 September 2011 through 9 September 2011, Toulouse, France, 2011, p. 1-4Conference paper (Refereed)
  • 213.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Kraft, Johan
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    A Framework for Real-Time Systems Migration to Multi-Cores2009Report (Other academic)
    Abstract [en]

    Power consumption and thermal problems limit a further increase of speed in single-core processors. Processor architects are therefore moving toward multicore processors. 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 single-core processor 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. In this paper we investigate challenges of migrating complex legacy real-time systems to multi-core architectures. We propose a partitioning algorithm to prepare the migration. Partitioning groups task and maps them to the different cores on the multicore processor, increasing system performance while ensuring correctness. We have run experiments that compare outputs of the algorithm to the outputs of an exhaustive search. Based on a cost function, the algorithm produces systems very close to optimal partitioning with respect to the cost function.

  • 214.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Kraft, Johan
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Towards Migrating Legacy Real-Time Systems to Multi-Core Platforms2008In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2008, p. 717-720Conference paper (Refereed)
    Abstract [en]

    Power consumption and thermal problems limit the single-core processors to be faster. Processor architects are therefore moving toward multi-coreprocessors. Developers of embedded real-time systems however hesitates a shift to multi-core processors, especially for existing "legacy" systemswhich have been developed with single-core processor assumptions. These systems have been developed and maintained by many developers over many years, and can not easily be replaced due to the huge development investments they represent. In this paper we investigate challenges ofmigrating complex legacy real-time systems to multi-core architectures. We propose componentization and partitioning to prepare the migration. Componentization groups logically related tasks into components (or subsystems). This provides an abstraction layer from a scheduling perspective, which facilitates migration. Partitioning maps tasks to the different cores on the multi-core processor, maximizing system performance while ensuring correctness.

  • 215.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    A Flexible Tool for Evaluating Scheduling, Synchronization and Partitioning Algorithms on Multiprocessors2010In: 2010 IEEE CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), 2010, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Multi-core platforms seem to be the way towards increasing performance of processors. Single-chip multiprocessors (multi-cores) are today the dominating technology for desktop computing. As the multi-cores are becoming the defacto processors, the need for new scheduling and resource sharing protocols has arisen.There are two major types of scheduling under multiprocessor/multi-core platforms. Global scheduling, under which migration of tasks among processors is allowed, and partitioned scheduling under which tasks are allocated onto processors and task migration is not allowed. The partitioned scheduling protocols suffer from the problem of partitioning tasks among processors/cores, which is a bin-packing problem. Heuristic algorithms have been developed for partitioning a task set on multiprocessor platforms.However, taking such technology to an industrial setting, it needs to be evaluated such that appropriate scheduling, synchronization and partitioning algorithms are selected.

    In this paper we present our work on a tool for investigation and evaluation of different approaches to scheduling, synchronization and partitioning on multi-core platforms. Our tool allows for comparison of different approaches with respect to a number of parameters such as number of schedulable systems and number of processors required for scheduling.The output of the tool includes a set of information and graphs to facilitate evaluation and comparison of different approaches.

  • 216.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Resource Hold Times under Multiprocessor Static-Priority Global Scheduling2011In: 17th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA'11), IEEE Computer Society, 2011, p. 197-206Conference paper (Refereed)
    Abstract [en]

    Recently there has been a lot of interest in coexisting of multiple independently-developed real-time applications on a shared open platform. On the other hand, emerging of multi-core platforms and the performance and possibilities they offer has attracted a lot of attention in multiprocessor real-time analysis, protocols and techniques. Co-executing independently- developedreal-time applications on a shared multiprocessor system, where each application executes on a dedicated sub set of processors, requires to overcome the problem of handling mutually exclusive shared resources among those applications. To handle resource sharing, it is important to determine the Resource Hold Time (RHT), i.e., the maximum duration of time that an application locks a shared resource. In this paper, we study resource hold times under multiprocessor static-priority global scheduling. We present how to compute RHT's for each resource in an application. We also show how to decrease the RHT's without compromising the schedulability of the application. We show that decreasing all RHT's for all shared resources is a multiobjective optimization problem and there can exist multiple Paretooptimal solutions.

  • 217.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Resource Sharing among Prioritized Real-Time Applications on Multi-cores2012Report (Other academic)
    Abstract [en]

    MSOS (Multiprocessors Synchronization protocol for real-time Open Systems) is a synchronization protocol for handling resource sharing among independently-developed realtime applications (components) on multi-core platforms. MSOS does not consider any priority setting among applications. To handle resource sharing based on the priority of applications, in this paper we propose a new protocol that allows for resource sharing among prioritized real-time applications on a multi-core platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the existing MSOS as well as to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP and OMLP. The evaluations show that MSOS-Priority mostly performs significantly better than alternative approaches.

  • 218.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Resource Sharing among Prioritized Real-Time Applications on Multiprocessors2012Report (Other academic)
    Abstract [en]

    MSOS (Multiprocessors Synchronization protocol for real-time Open Systems) is a synchronization protocol for handling resource sharing among independently-developed real-time applications (components) on multi-core platforms.MSOS does not consider any priority setting among applications.To handle resource sharing based on the priority of applications, in this paper we propose a new protocol that allows for resource sharing among prioritized real-time applications on a multi-core platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the existing MSOS as well as to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP and OMLP. The evaluations show that MSOS-Priority mostly performs significantly better than alternative approaches.

  • 219.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Resource Sharing among Real-Time Components under Multiprocessor Clustered Scheduling2013In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 49, no 5, p. 580-613Article in journal (Refereed)
    Abstract [en]

    In this paper we propose a general synchronization protocol for resource sharing among independently-developed real-time applications (components) on multi-core platforms. This protocol is a generalization of a previously proposed synchronization protocol (MSOS). In our proposed protocol, each component is statically allocated on a dedicated subset of processors (called cluster). A component has its own internal scheduler by which its tasks are scheduled. In this paper we focus on multiprocessor global fixed-priority preemptive scheduling algorithms to be used to schedule the tasks inside each component. Sharing the local resources is handled by the Priority Inheritance Protocol (PIP). For sharing the global resources (inter-component resource sharing) we have studied usage of FIFO and Round-Robin queues for access the resources across the components and usage of FIFO and prioritized queues inside the components. We have derived schedulability analysis for the different queue handling alternatives and compared their performance by using experimental evaluations. Finally, we have shown that the integration phase can be formulated in the form of a nonlinear integer programming problem where solution techniques in this domain can be used to minimize the total number of processors required to guarantee the schedulability of all components. As a proof of concept we have only provided the formulation for FIFO queues.

  • 220.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Blocking-Aware Partitioning for Multiprocessors2010Report (Other academic)
    Abstract [en]

    In the multi-core and multiprocessor domain there are two scheduling approaches, global and partitioned scheduling. Under global scheduling each task can execute on any processor while under partitioned scheduling tasks are allocated to processors and migration of tasks among processors is not allowed. Under global scheduling the higher utilization bound can be achieved, but in practice the overheads of migrating tasks is high. On the other hand, besides simplicity and efficiency of partitioned scheduling protocols, existing scheduling and synchronization methods developed for uniprocessor platforms can more easily be extended to partitioned scheduling. This also simplifies migration of existing systems to multi-cores. An important issue related to partitioned scheduling is how to distribute tasks among processors/cores to increase performance offered by the platform. However, existing methods mostly assume independent tasks while in practice a typical real-time system contains tasks that share resources and they may block each other. In this paper we propose a blocking-aware partitioning algorithm to distribute tasks onto different processors. The proposed algorithm allocates a task set onto processors in a way that blocking times of tasks are decreased. This reduces the total utilization which has the potential to decrease the total number of needed processors/cores.

  • 221.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Partitioning Real-Time Systems on Multiprocessors with Shared Resources2010In: Lecture Notes in Computer Science, vol. 6490, Springer, 2010, p. 253-269Chapter in book (Refereed)
    Abstract [en]

    There are two main approaches to task scheduling on multiprocessor/multi-core platforms; 1) global scheduling, under which migration of tasks among processors is allowed, and 2) partitioned scheduling under which tasks are allocated onto processors and task migration is not allowed. Under global scheduling a higher utilization bound can be achieved, but in practice the overheads of migrating tasks is high. On the other hand under partitioned scheduling, besides simplicity and efficiency, existing scheduling and synchronization methods developed for uniprocessor platforms can more easily be extended to partitioned scheduling. However the partitioned scheduling protocols suffer from the problem of partitioning tasks among processors/cores which is a bin-packing problem. Therefore, several heuristic algorithms have been developed for partitioning a task set on multiprocessor platforms. However, these algorithms typically assume independent tasks while in practice real-time systems often contain tasks that share resources and hence may block each other.

    In this paper we propose a blocking-aware partitioning algorithm which allocates a task~set onto processors in a way that the overall amount of blocking times of tasks are decreased. The algorithm reduces the total utilization which, in turn, has the potential to decrease the total number of required processors (cores). In this paper we evaluate our algorithm and compare it with an existing similar algorithm. The comparison criteria includes both number of schedulable systems as well as processor reduction performance.

  • 222.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Compositional and Adaptive Scheduling of Cyber-Physical Systems2012In: , 2012Conference paper (Refereed)
  • 223.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Compositionality and CPS from a platform perspective2011In: Proceedings - 1st International Workshop on Cyber-Physical Systems, Networks, and Applications, CPSNA 2011, Workshop Held During RTCSA 2011, 2011, p. 57-60Conference paper (Refereed)
    Abstract [en]

    Cyber Physical Systems (CPS) comprise the integration of embedded computer systems and the physical processes that these computer systems interact with. Examples of such systems stretch from small embedded devices, e.g., intelligent sensor systems, to larger and often complex industrial systems, e.g., industrial automation systems. These systems are not only subject to functional requirements, but also non-functional requirements such as timing, resource usage, and reliability. CPS development (including software development) is substantially facilitated if the system parts can be developed and verified in isolation, and if the correctness of the system can be inferred from the correctness of its parts. Such modular and compositional design of software systems has for a long time been considered the holy-grail of system design, and is unfortunately only possible in selected scenarios. This paper covers one such scenario: using hierarchical runtime mechanisms in the platform to enable predictable resource usage and temporal isolation of CPS software. Our overall goal is to develop cost efficient mechanisms that are applicable for a wide range of systems. © 2011 IEEE.

  • 224.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Proceedings of the Work-in-Progress Session of the 16th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA'10)2010Conference proceedings (editor) (Other academic)
  • 225.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Engineering.
    Reducing pessimism and increasing flexibility in the controller area network2003Licentiate thesis, comprehensive summary (Other scientific)
  • 226.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Reducing Pessimism and Increasing Flexibility in the Controller Area Network2003Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    The Controller Area Network (CAN) is a widely used real-time communication network for automotive and other embedded applications. As new applications continue to evolve, the complexity of distributed CAN based systems increase. However, CAN's maximum speed of 1 Mbps remains fixed, leading to performance bottlenecks. In order to make full use of this scarce bandwidth, methods for increasing the achievable utilisation are needed. Traditionally, real-time scheduling theory has targeted hard real-time systems, which most of the time are safety critical. Since these systems (by definition) are not allowed to have any timing flaws, analysis techniques need to take all possible scenarios of execution combinations and execution times of the system into consideration. This will result in a system that is configured for the worst possible scenario. Whether this scenario is likely, or even possible, in the real system is not considered. Hence, the result may be an unnecessarily expensive system, with potentially overly provisioned resources. In this thesis we address two issues. In the first part, we investigate how to loosen up pessimistic real-time analysis in a controlled way, thereby allowing the designer to make well-founded trade-offs between the level of real-time guarantee and the system cost. Specifically, we investigate and model the bit-stuffing mechanism in CAN in order to retrieve representative distributions of stuff-bits, which we then use in the response time analysis instead of the worst-case values normally used. We evaluate the validity of these stuff-bit distributions in two case studies, and we integrate this representation of message frame length with the classical CAN worst-case response-time analysis. In the second part of the thesis, we propose a novel way of scheduling the CAN. By providing server-based scheduling, bandwidth isolation between users is guaranteed. This increases the flexibility of CAN, by providing efficient handling of sporadic and aperiodic message streams. Server-based scheduling also has the potential to allow higher network utilisation compared to CAN's native scheduling. The performance and properties of server-based scheduling of CAN is evaluated using simulation. Also, the server-based scheduling is applied in an end-to-end analysis. Keywords: controller area network, CAN, real-time communication, real-time analysis, reliability trade-off analysis, bit-stuffing, server-based scheduling

  • 227.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Share-Driven Scheduling of Embedded Networks2006Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Many products are built from more or less independently developed subsystems. For instance, a car consists of subsystems for transmission, braking, suspension, etc. These subsystems are frequently controlled by an embedded computer system. In the automotive industry, as well as in other application domains, there is currently a trend from an approach where subsystems have dedicated computer hardware and other resources (a federated approach) to an approach where subsystems share hardware and other resources (an integrated approach). This is motivated by a strong pressure to reduce product cost, at the same time as an increasing number of subsystems are being introduced.

    When integrating subsystems, it is desirable that guarantees valid before integration are also valid after integration, since this would eliminate the need for costly reverifications. The computer network is a resource that is typically shared among all subsystems. Hence, a central issue when integrating subsystems is to provide an efficient scheduling of message transmissions on the network. There are essentially three families of schedulers that can be used: priority-driven schedulers that assign priorities to messages, time-driven schedulers that assign specific time-slots for transmission of specific messages, and share-driven schedulers that assign shares of the available network capacity to groups of messages.

    This thesis presents a framework for share-driven scheduling, to be implemented and used in embedded networks, with the aim to facilitate subsystem integration by reducing the risk of interference between subsystems. The framework is applied in the automotive domain.

    The initial parts of the thesis give an overview of systems, subsystems and network technologies found and used in the automotive domain. Then, the share-driven scheduling framework is presented, analytically investigated and proven, as well as evaluated in a simulation study. Finally it is shown how the framework is to be configured and used in the context of subsystem integration. The results show that the framework allows for flexible and efficient scheduling of messages with real-time constraints, facilitating integration of subsystems from a network point of view.

  • 228.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Åsberg, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    J. Bril, Reinder
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Mälardalen University, School of Innovation, Design and Engineering.
    Hierarchical Scheduling of Complex Embedded Real-Time Systems2009In: Ecole d'Ete Temps-REel (ETR'09), Paris, France, 2009, p. 129-142Conference paper (Refereed)
  • 229.
    Nolte, Thomas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Hansson, Hans
    Mälardalen University, Department of Computer Science and Electronics.
    Lo Bello, Lucia
    University of Catania, Catania, Italy .
    Integration of networked subsystems in a resource constrained environment2006In: Proceedings of 11th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA'06), Prague, Czech Republic, 2006, p. 905-912Conference paper (Refereed)
    Abstract [en]

    When developing embedded systems, there is currently a trend to move from a traditional federated approach, where computer systems are developed for their own dedicated hardware architecture, to an integrated approach, where computer systems are encapsulated as subsystems and later integrated on a shared hardware architecture. The task of integrating subsystems is complex, and in resource constrained systems efficient techniques and methods are required. In this paper the issue of subsystem integration is thoroughly discussed, and it is shown how to use Server-CAN, a network scheduler for the Controller Area Network, in the context of subsystem integration. As the network is a resource shared by all subsystems in adistributed architecture, its role in the integration process is particularly important. Here, the usage of an efficient and flexible network scheduler is essential.

  • 230.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Hansson, Hans
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Punnekkat, Sasikumar
    Mälardalen University, School of Innovation, Design and Engineering.
    Timing Analysis of CAN-Based Automotive Communication Systems2008In: Automotive Embedded Systems Handbook, CRC Press, 2008Chapter in book (Other academic)
  • 231.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. ABB Corporate Research, Västerås, Sweden.
    Liu, Meng
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisper, Björn
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Challenges with Probabilities in Response-Time Analysis of Real-Time Systems2014In: 5th International Real-Time Scheduling Open Problems Seminar RTSOPS'14, 2014Conference paper (Refereed)
    Abstract [en]

    In this paper we present and discuss some of the key open problems and challenges with using probabilities in Response-Time Analysis (RTA) of "real" real-time systems, i.e., challenges inherent in the real software to be analyzed.

  • 232.
    Nolte, Thomas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Lo Bello, Lucia
    Mälardalen University, Department of Computer Science and Electronics.
    Hansson, Hans
    Mälardalen University, Department of Computer Science and Electronics.
    Facilitating subsystem integration by decoupling priority and identifier in CAN messages2006In: Proceedings of the 5th International Workshop on Real-Time Networks (RTN'06) in conjunction with the 18th Euromicro International Conference on Real-Time Systems (ECRTS'06), Dresden, Germany, 2006Conference paper (Refereed)
  • 233.
    Nolte, Thomas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nolin, M.
    Hansson, H. A.
    Mälardalen University, Department of Computer Science and Electronics.
    Real-time server-based communication with CAN2005In: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 1, no 3, p. 192-200Article in journal (Refereed)
    Abstract [en]

    This paper investigates the concept of share-driven scheduling of networks using servers with real-time properties. Share-driven scheduling provides fairness and bandwidth isolation between predictable as well as unpredictable streams of messages on the network. The need for this kind of scheduled real-time communication network is high in applications that have requirements on flexibility, both during development for assigning communication bandwidth to different applications, and during run-time to facilitate dynamic addition and removal of system components. We illustrate the share-driven scheduling concept by applying it to the popular controller area network (CAN). We propose a scheduling mechanism that we call simple server-scheduled CAN (S-3-CAN), for which we also present an associated timing analysis. Additionally, we present a variant of S'-CAN called periodic server-scheduled CAN (PS2-CAN), which for some network configurations gives lower worst-case response-times than S-3-CAN. Also for this improvement, a timing analysis is presented. Moreover, we use simulation to evaluate the timing performance of both S-3-CAN and PS2-CAN, comparing them with other scheduling mechanisms.

  • 234.
    Nolte, Thomas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nyström, Dag
    Mälardalen University, Department of Computer Science and Electronics.
    Introducing Substitution-Queries in Distributed Real-Time Database Management Systems2005In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2005, p. 707-714Conference paper (Other academic)
    Abstract [en]

    This paper introduces query mechanisms that allow automotive control-systems (using a distributed real-time database management system(RTDBMS)) to be queried, monitored and stimulated during run-time without violating its temporal properties. The mechanisms are completely transparent to the control application since they are handled by the RTDBMS. The COMET RTDBMS is extended with ad hoc capabilities to support the introduction of subscription and substitution queries, which are used for monitoring and stimulation. These queries are intended to be used by service and calibration tools to help in the development and maintenance of modern automotive systems. Using these queries could reduce development costs, result in higher quality of the system design and consequently yield higher reliability.

  • 235.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Passerone, Roberto
    University of Trento, Trento, Italy.
    Guest Editorial Special Section on Real-Time and (Networked) Embedded Systems2009In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 5, no 3, p. Article number 5196872-Article in journal (Refereed)
  • 236.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Passerone, Roberto
    University of Trento, Italy.
    Guest Editorial Special Section on Real-Time and (Networked) Embedded Systems III2012In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 8, no 2, p. 321-321Article in journal (Other academic)
  • 237.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Passerone, Roberto
    University of Trento.
    Guest Editorial Special Section on Real-Time and (Networked) Embedded Systems-II2010In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 6, no 4, p. 475-478Article in journal (Refereed)
  • 238.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    A Synchronization Protocol for Temporal Isolation of Software Components in Vehicular Systems2009In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 5, no 4, p. 375-387Article in journal (Refereed)
    Abstract [en]

    We present a method that allows for integration of individually developed functions of software components into a predictable real-time system. The method has been designed to provide a lightweight mechanism that gives temporal firewalls between functions, preventing unpredictable side effects during function integration. The method maps well to the AUTOSAR (AUTomotive Open System ARchitecture) software component model and can thus be used to facilitate seamless and predictable integration and isolation of AUTOSAR components that have been developed by different manufacturers. Specifically, this paper presents a protocol for synchronization in a hierarchical real-time scheduling framework. Using our protocol, a software component does not need to know, and is not dependent on, the timing behavior of software components belonging to other functions; even though they share mutually exclusive resources. In this paper, we also prove the correctness of our approach and evaluate its efficiency and cost in terms of system load in a vehicular context. 

  • 239.
    Rajabi, Aboozar
    et al.
    University of Tehran, Tehran, Iran.
    Faragardi, Hamid Reza
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    An Efficient Scheduling of HPC Applications on Geographically Distributed Cloud Data Centers2014In: Computer Networks and Distributed Systems: International Symposium, CNDS 2013, Tehran, Iran, December 25-26, 2013, Revised Selected Papers, Springer, 2014, p. 155-167Chapter in book (Refereed)
    Abstract [en]

    Cloud computing provides a flexible infrastructure for IT industries to run their High Performance Computing (HPC) applications. Cloud providers deliver such computing infrastructures through a set of data centers called a cloud federation. The data centers of a cloud federation are usually distributed over the world. The profit of cloud providers strongly depends on the cost of energy consumption. As the data centers are located in various corners of the world, the cost of energy consumption and the amount of CO2 emission in dif-ferent data centers varies significantly. Therefore, a proper allocation of HPC applications in such systems can result in a decrease of CO2 emission and a substantial increase of the providers’ profit. Reduction of CO2 emission also mitigates the destructive environmental impacts. In this paper, the problem of scheduling HPC applications on a geographically distributed cloud federation is scrutinized. To address the problem, we propose a two-level scheduler which is able to reach a good compromise between CO2 emission and the profit of cloud provider. The scheduler should also satisfy all HPC applications’ deadline and memory constraints. Simulation results based on a real intensive workload indi-cate that the proposed scheduler reduces the CO2 emission by 11% while at the same time it improves the provider’s profit in average.

  • 240.
    Relefors, J.
    et al.
    Robotdalen AB, Västerås, Sweden.
    Momeni, Mahdi
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pettersson, Lars
    Skanska Sweden AB, Stockholm, Sweden.
    Hellström, Erik
    Robotdalen AB, Västerås, Sweden.
    Thunell, A.
    Robotdalen AB, Västerås, Sweden.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards Automated Installation of Reinforcement Using Industrial Robots2019In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 1595-1598Conference paper (Refereed)
    Abstract [en]

    The construction industry is today among the least automated industries with a long tradition of utilizing manual labour. Despite the potential benefits of automation, only a few examples of using robots to automate (parts of) construction have been presented over the past years. In this paper we present our ongoing work towards automated installation of reinforcement, a traditionally very heavy and labour intensive work. We use industrial robots and we discuss the potential benefits and challenges of such robotic automation in construction. Our overall goal is to achieve a fully automated robotic solution for flexible serial production of custom made non-identical reinforcement cages. In the paper we highlight and analyse the main challenges that must be addressed in order to reach a functioning and efficient solution.

  • 241.
    Salman, Chaudhary Awais
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Västers, Sweden.
    Struhar, Vaclav
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fogification of industrial robotic systems: Research challenges2019In: IoT-Fog 2019 - Proceedings of the 2019 Workshop on Fog Computing and the IoT, Association for Computing Machinery, Inc , 2019, p. 41-45Conference paper (Refereed)
    Abstract [en]

    To meet the demands of future automation systems, the architecture of traditional control systems such as the industrial robotic systems needs to evolve and new architectural paradigms need to be investigated. While cloud-based platforms provide services such as computational resources on demand, they do not address the requirements of real-time performance expected by control applications. Fog computing is a promising new architectural paradigm that complements the cloud-based platform by addressing its limitations. In this paper, we analyse the existing robot system architecture and propose a fog-based solution for industrial robotic systems that addresses the needs of future automation systems. We also propose the use of Time-Sensitive Networking (TSN) services for real-time communication and OPC-UA for information modelling within this architecture. Additionally, we discuss the main research challenges associated with the proposed architecture.

  • 242.
    Sandström, Kristian
    et al.
    ABB Corporate Research.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    J. Bril, Reinder
    TU/e, Netherlands .
    On Jitter in Time Partitioned Real-Time Systems2012In: Emerging Technologies & Factory Automation (ETFA), 2012 IEEE 17th Conference on, 2012, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Recent trends towards adopting hypervisors, hierarchical scheduling, and other virtualization technologies that achieve partitioned access to the CPU and other resources impose significant impact with respect to jitter performance in embedded real-time systems. In this paper we make a first step towards characterization, modeling and calculation of this jitter.

  • 243.
    Sandström, Kristian
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Vulgarakis, Aneta
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lindgren, Markus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Virtualization Technologies in Embedded Real-Time Systems2013Conference paper (Refereed)
    Abstract [en]

    Virtualization is a promising solution to develop complex embedded systems with real-time requirements. This paper discusses the current state-of-the-art in virtualization technologies, with a particular focus on solutions for embedded real-time systems. Several such solutions have been developed over the past decade, and in this paper we give an overview of the more well known technologies and we provide a comparative assessment of key virtualization techniques available in these solutions. Gaps and lacking pieces are identified and further development and research is suggested.

  • 244.
    Santos, R.
    et al.
    IEETA, University of Aveiro, Aveiro, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Pedreiras, P.
    IEETA, University of Aveiro, Aveiro, Portugal.
    Almeida, L.
    University of Porto.
    Multi-level hierarchical scheduling in ethernet switches2011In: Embedded Syst. Week, ESWEEK - Proc. ACM Int. Conf. Embedded Softw., EMSOFT, 2011, p. 185-193Conference paper (Refereed)
    Abstract [en]

    The complexity of Networked Embedded Systems (NES) has been growing steeply, due to increases both in size and functionality, and is becoming a major development concern. This situation is pushing for paradigm changes in NES design methodologies towards higher composability and flexibility. Component-oriented design technologies, in particular supported by server-based scheduling, seem to be good candidates to provide the needed properties. As a response we developed a multi-level hierarchical serverbased architecture for Ethernet switches that provides composability and supports online adaptation and reconfiguration. This paper extends our work, presenting the associated response-time based schedulability analysis, necessary for the admission control procedure. Additionally, we have derived the temporal complexity of the analysis, which is shown to be O(n2), where n is the number of higher priority components associated with a given server. Finally, we present a proof-of-concept implementation and a set of experimental results that validates the analysis. Copyright © 2011 ACM.

  • 245.
    Santos, Rui
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering.
    Pedreiras, Paulo
    Mälardalen University, School of Innovation, Design and Engineering.
    Schedulability Analysis for Multi-level Hierarchical Server Composition in Ethernet Switches2010In: 9th International Workshop on Real-Time Networks RTN'2010, Brussels, Belgium, 2010Conference paper (Refereed)
  • 246.
    Santos, Rui
    et al.
    IEETA / University of Aveiro Aveiro, Portugal.
    Pedreiras, Paulo
    IEETA / University of Aveiro Aveiro, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    University of Porto Porto, Portugal.
    A Demonstration of Hierarchical Scheduling over Ethernet2011In: Real-Time SystemS @ Work, the Open Demo Session of Real-Time Techniques and Technologies of the 32nd IEEE Real-Time Systems Symposium (RTSS'11), 2011Conference paper (Refereed)
  • 247. Santos, Rui
    et al.
    Pedreiras, Paulo
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering.
    Demonstrating an Ethernet Switch Enhanced with Hierarchical Scheduling2011Conference paper (Refereed)
  • 248.
    Santos, Rui
    et al.
    University of Porto.
    Pedreiras, Paulo
    University of Aveiro.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering.
    Hierarchical Server-based Traffic Scheduling in Ethernet Switches2010Conference paper (Refereed)
  • 249.
    Santos, Rui
    et al.
    University of Aveiro, Aveiro, Portugal .
    Pedreiras, Paulo
    University of Aveiro, Aveiro, Portugal .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    University of Porto, Porto, Portugal.
    Hierarchical server-based traffic scheduling in ethernet switches2011In: ACM SIGBED Review, ISSN 1551-3688, Vol. 8, no 1, p. 68-69Article in journal (Refereed)
    Abstract [en]

    Distributed Embedded Real-Time Systems (DERTS) are ever more complex, consisting of an increasing number of nodes with more functionality and handling more data. This scenario is pushing for paradigm changes in the methodologies to design complex DERTS. Namely, component-oriented design methodologies, exhibiting the composability property are considered an effective means to tackle the growing complexity of DERTS. Server-oriented architectures have proven to be an effective means to enable controlled resource sharing, providing composability among application components as well as between the application software and the hardware platform on which they execute.

  • 250.
    Santos, Rui
    et al.
    IEETA/University of Aveiro.
    Pedreiras, Paulo
    IEETA/University of Aveiro.
    Yekeh, Farahnaz
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    University of Porto.
    On Hierarchical Server-based Communication with Switched Ethernet2010In: Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2010, 2010Conference paper (Refereed)
    Abstract [en]

    Ethernet is becoming a common network technology for industrial and factory automation systems and, in recent years, a big effort has been made in enabling real-time communications using Ethernet technology. Many of these systems are complex, extend over relatively large places and/or integrate a significant number of nodes, thus requiring the use of multiple switches (hop). In this paper we look into the usage of Flexible Time-Triggered (FTT) enabled Ethernet switches in this class of systems, more specifically using the recently proposed server-based scheduling mechanism supported by this protocol. The paper proposes and validates a resource reservation protocol, presents a method for computing the end-to-end deadlines and discusses possible strategies for the deadline partitioning.

23456 201 - 250 of 284
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