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  • 1.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David
    CISTER, INESC TEC, ISEP.
    Pinho, Luís Miguel
    CISTER, INESC TEC, ISEP.
    Contract Based Verification of IEC 614992017In: IEEE International Conference on Industrial Informatics (INDIN), Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, 132-141 p., 7819147Conference paper (Refereed)
    Abstract [en]

    The IEC 61499 standard proposes an event drivenexecution model for component based (in terms of FunctionBlocks), distributed industrial automation applications. However,the standard provides only an informal execution semantics, thusin consequence behavior and correctness relies on the designdecisions made by the tool vendor. In this paper we presentthe formalization of a subset of the IEC 61499 standard inorder to provide an underpinning for the static verification ofFunction Block models by means of deductive reasoning. Specifically,we contribute by addressing verification at the component,algorithm, and ECC levels. From Function Block descriptions, enrichedwith formal contracts, we show that correctness of componentcompositions, as well as functional and transitional behaviorcan be ensured. Feasibility of the approach is demonstrated bymanually encoding a set of representative use-cases in WhyML,for which the verification conditions are automatically derived(through the Why3 platform) and discharged (using automaticSMT-based solvers). Furthermore, we discuss opportunities andchallenges towards deriving certified executables for IEC 61499models.

  • 2.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    End-to-End Response Time of 61499 Distributed Applications over Switched Ethernet2017In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 13, no 1, 287-297 p.Article in journal (Refereed)
    Abstract [en]

    The IEC 61499 standard provides means to specify distributed control systems in terms of function blocks. For the deployment, each device may hold one or many logical resources, each consisting of a function block network with service interface blocks at the edges. The execution model is event driven (asynchronous), where triggering events may be associated with data (and seen as messages). In this paper, we propose a low complexity implementation technique allowing to assess end-to-end response times of event chains spanning over a set of networked devices. Based on a translation of IEC 61499 to RTFM1-tasks and resources, the response time for each task in the system at device-level can be derived using established scheduling techniques. In this paper, we develop a holistic method to provide safe end-to-end response times taking both intra- and inter-device delivery delays into account. The novelty of our approach is the accuracy of the system scheduling overhead characterization. While the device-level (RTFM) scheduling overhead was discussed in previous works, the network-level scheduling overhead for switched Ethernets is discussed in this paper. The approach is generally applicable to a wide range of COTS Ethernet switches without a need for expensive custom solutions to provide hard real-time performance. A behavior characterization of the utilized switch determines the guaranteed response times. As a use case, we study the implementation onto (single-core) ARMcortex based devices communicating over a switched Ethernet network. For the analysis, we define a generic switch model and an experimental setup allowing us to study the impact of network topology as well as 802.1Q quality of service in a mixed critical setting. Our results indicate that safe sub millisecond end-to-end response times can be obtained using the proposed approach.

  • 3.
    Blech, Jan Olaf
    et al.
    RMIT University, Melbourne.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David
    ISEP, Instituto Superior de Engenharia do Porto.
    Vyatkin, Valeriy
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Zoitl, Alois
    fortiss GmbH, Munich.
    A Comparison of Formal Verification Approaches for IEC 614992016In: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA): Berlin, 6-9 Sept. 2016, Piscataway, NJ: IEEE conference proceedings, 2016, 7733636Conference paper (Refereed)
    Abstract [en]

    Engineering and computer science have come up with a variety of techniques to increase the confidence in systems, increase reliability, facilitate certification, improve reuse and maintainability, improve interoperability and portability. Among them are various techniques based on formal models to enhance testing, validation and verification. In this paper, we are concentrating on formal verification both at runtime and design time of a system. Formal verification of a system property at design time is the process of mathematically proving that the property indeed holds. At runtime, one can check the validity of the property and report deviations by monitoring the system execution. Formal verification relies on semantic models, descriptions of the system and its properties. We report on ongoing verification work and present two different approaches for formal verification of IEC 61499-based programs. We provide two examples of ongoing work to exemplify the design and the runtime verification approaches

  • 4.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Fresk, Emil
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    Abstract Timers and their Implementation onto the ARM Cortex-M family of MCUs2016In: Vol. 13, no 1Article in journal (Refereed)
    Abstract [en]

    Real-Time For the Masses (RTFM) is a set of languages andtools being developed to facilitate embedded software developmentand provide highly ecient implementations gearedto static verication. The RTFM-kernel is an architecturedesigned to provide highly ecient and predicable Stack ResourcePolicy based scheduling, targeting bare metal (singlecore)platforms.We contribute by introducing a platform independent timerabstraction that relies on existing RTFM-kernel primitives.We develop two alternative implementations for the ARMCortex-M family of MCUs: a generic implementation, usingthe ARM dened SysTick/DWT hardware; and a targetspecic implementation, using the match compare/free runningtimers. While sacricing generality, the latter is moreexible and may reduce overall overhead. Invariants for correctnessare presented, and methods to static and run-timeverication are discussed. Overhead is bound and characterized.In both cases the critical section from release timeto dispatch is less than 2us on a 100MHz MCU. Queue andtimer mechanisms are directly implemented in the RTFMcorelanguage (-core in the following) and can be includedin system-wide scheduling analysis.

  • 5.
    Lindner, Marcus
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    RTFM-core: course in compiler construction2016In: The SIGBED Review, ISSN 1551-3688, Vol. 14, no 1, 29-36 p.Article in journal (Refereed)
    Abstract [en]

    The course in Compiler Construction is part of the Computer Science masters program at Luleå University of Technology (LTU). Since the fall of 2014, the course is given by the Embedded Systems group. This paper outlines the course syllabus and its relation to CPS/IoT and embedded systems in general. In particular, the course introduces domain specific language design with the outset from the imperative RTFM-core language. Students are exposed to design choices for the language, spanning from programming model, compiler design issues, back-end tools, and even runtime environments. The intention is to give a holistic perspective and motivate the use of compilation techniques towards robust, efficient, and verifiable (embedded) software. Of course, developing basic skills is not overlooked and as part of the laboratory assignments, students extend the min-imalistic Object Oriented language RTFM-cOOre and develop the compiler accordingly targeting the RTFM-core language as an intermediate representation. As the RTFM-core/-cOOre compilers are implemented using OCaml/Men-hir, the students are also exposed to functional languages and to their advantages in the context of compiler construction. However, for their own development they may choose alternative design tools and languages. This gives us the opportunity to review and correlate achievements and efficiency to the choice of tools and languages and it is an outset for future course development.

  • 6.
    Lindner, Marcus
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Safe tasks: run time verification of the RTFM-lang model of computation2016In: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA): Berlin, 6-9 Sept. 2016, Piscataway, NJ: IEEE conference proceedings, 2016, 7733550Conference paper (Refereed)
    Abstract [en]

    Embedded systems for critical applications are typicallyspecified with requirements on predictable timing andsafety. While ensuring predictable timing, the RTFM-lang (Real-Time For the Masses) model of computation (MoC) currentlylacks memory access protection among real-time tasks. In thispaper, we discuss how to safely verify task execution given aspecification using the RTFM-MoC. Furthermore, an extensionto the RTFM-core infrastructure is outlined and tested with usecases of embedded development. We propose a method for runtime verification exploiting memory protection hardware. Forthis purpose, we introduce memory resources to the declarativelanguage RTFM-core allowing compliance checks. As a proofof concept, compiler support for model analysis and automaticgeneration of run time verification code is implemented togetherwith an isolation layer for the RTFM-kernel. With this verificationfoundation, functional run time checks as well as furtheroverhead assessments are future research questions.

  • 7.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luís Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    Towards Certified Compilation of RTFM-core Applications2016In: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA): Berlin, 6-9 Sept. 2016, Piscataway, NJ: IEEE conference proceedings, 2016, 7733551Conference paper (Refereed)
    Abstract [en]

    Concurrent programming is dominated by threadbased solutions with lock based critical sections. Careful attentionhas to be paid to avoid race and deadlock conditions. Real-Timefor The Masses (RTFM) takes an alternative language approach,introducing tasks and named critical sections (via resources)natively in the RTFM-core language. RTFM-core programs canbe compiled to native C-code, and efficiently executed ontosingle-core platforms under the Stack Resource Policy (SRP)by the RTFM-kernel. In this paper we formally define thewell-formedness criteria for SRP based resource management,and develop a certified (formally proven) implementation ofthe corresponding compilation from nested critical sections ofthe input RTFM-core program to a resulting flat sequence ofprimitive operations and scheduling primitives. Moreover weformalise the properties for resource ceilings under SRP anddevelop a certified algorithm for their computation.The feasibility of the described approach is shown throughthe adoption of the Why3 platform, which allows the necessaryverification conditions to be automatically generated and dischargedthrough a variety of automatic external SMT-solversand interactive theorem provers. Moreover, Why3 supports theextraction of certified Ocaml code for proven implementationsin WhyML. As a proof of concept the certified extracteddevelopment is demonstrated on an example system.

  • 8.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    A Formal Perspective on IEC 61499 Execution Control Chart Semantics2015In: 2015 IEEE Trustcom/BigDataSE/ISPA: Helsinki, 20-22 Aug. 2015, Piscataway, NJ: IEEE Communications Society, 2015, 293-300 p., 7345663Conference paper (Refereed)
    Abstract [en]

    The IEC 61499 standard proposes an event driven execution model for distributed control applications for which an informal execution semantics is provided. Consequently, run-time implementations are not rigorously described and therefore their behavior relies on the interpretation made by the tool provider. In this paper, as a step towards a formal semantics, we focus on the Execution Control Chart semantics, which is fundamental to the dynamic behavior of Basic Function Block elements. In particular we develop a well-formedness criterion that ensures a finite number of Execution Control Chart transitions for each triggering event. We also describe the first step towards the mechanization of the well-formedness checking algorithm in the Coq proof-assistant so that, ultimately, we are able to show, once andforall,thatthisalgorithmiseffectivelycorrectwithrespectto our proposed execution semantics. The algorithm is extractable from the mechanization in a correct-by-construction way, and can be directly incorporated in certified toolchain for analysis, compilation and execution of IEC 61499 models. As a proof of concept a prototype tool RTFM-4FUN has been developed. It performs well-formedness checks on Basic Function Blocks using the extracted algorithm’s code.

  • 9.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Vyatkin, Valeriy
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    A Real-Time Semantics for the IEC 61499 standard2015In: Proceedings of 2015 IEEE 20th International Conference on Emerging Technologies & Factory Automation (ETFA 2015): Luxembourg, 8-11 Sept. 2015, Piscataway, NJ: IEEE Communications Society, 2015, 7301558Conference paper (Refereed)
    Abstract [en]

    The IEC 61499 standard provides an executable model for distributed control systems in terms of interacting function blocks. However, the current IEC 61499 standard lacks appropriate timing semantics for the specification of timing requirements, reasoning on timing properties at the model level, and for the timing verification of a specific deployment. In this paper we address this fundamental shortcoming by proposing Real-Time-4-FUN, a real-time semantics for IEC 61499. The key property is the preservation of non-determinism, allowing us to reason on (and verify) timing properties at the model level without assuming any specific scheduling policy or stipulating specific order of execution for the deployment. This provides for a clear separation of concerns, where the designer can focus on properties of the application prior to, and separately from, deployment verification. The proposed timing semantics is backwards compatible to the current standard, thus allow for reuse of existing designs. The transitional property allows timing requirements to propagate to downstream sub-systems, and can be utilized for scheduling both at device and network level. Based on a translation to RTFM-tasks and resources, IEC 61499 the models can be analyzed, compiled and executed. As a proof of concept the timing semantics has been experimentally implemented in the RTFM-core language and the accompanying (thread based) RTFM-RT run-time system.

  • 10.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    Response Time for IEC 61499 over Ethernet2015In: IEEE International Conference on Industrial Informatics: INDIN 2015, Cambridge, UK, July 22-24, 2015. Proceedings, Piscataway, NJ: IEEE Communications Society, 2015, 1206-1212 p., 7281907Conference paper (Refereed)
    Abstract [en]

    The IEC 61499 standard provides means to specify distributed control systems in terms of function blocks. For the deployment, each device may hold one or many logical resources, each consisting of a function block network with service interface blocks at the edges. The execution model is event driven (asynchronous), where triggering events may be associated with data (and seen as a message). In this paper we propose a low complexity implementation technique allowing to asses end-to-end response time of event chains spanning a networked devices. Based on a translation of IEC 61499 to RTFM-tasks and resources, the response time for each task in the system can be derived using established scheduling techniques. In this paper we develop a method to provide safe end-to-end response time taking both intra- and inter-device delivery delays into account. As a use case we study the implementation onto (single-core) ARMcortex based devices communicating over a switched Ethernet network. For the analysis we define a generic switch model, and an experimental setup allowing us to study the impact of network topology as well as 802.1Q quality of service in a mixed critical setting. Our results indicate that safe sub milli-second end-to-end response times can be obtained using the proposed approach.

  • 11.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    RTFM-core: Language and Implementation2015In: 2015 IEEE 10th Conference on Industrial Electronics and Applications (ICIEA): Auckland, 15-17 June 2015, Piscataway, NJ: IEEE Communications Society, 2015, 990-995 p., 7334252Conference paper (Refereed)
    Abstract [en]

    Robustness, real-time properties and resource efficiency are key properties to embedded devices of the CPS/IoT era. In this paper we propose a language approach RTFMcore, and show its potential to facilitate the development process and provide highly efficient and statically verifiable implementations. Our programming model is reactive, based on the familiar notions of concurrent tasks and (single-unit) resources. The language is kept minimalistic, capturing the static task, communication and resource structure of the system. Whereas C-source can be arbitrarily embedded in the model, and/or externally referenced, the instep to mainstream development is minimal, and a smooth transition of legacy code is possible. A prototype compiler implementation for RTFM-core is presented. The compiler generates C-code output that compiled together withtheRTFM-kernelprimitivesrunsonbaremetal.TheRTFMkernel guarantees deadlock-lock free execution and efficiently exploits the underlying interrupt hardware for static priority scheduling and resource management under the Stack Resource Policy. This allows a plethora of well-known methods to static verification (response time analysis, stack memory analysis, etc.) to be readily applied. The proposed language and supporting tool-chain is demonstrated by showing the complete process from RTFM-core source code into bare metal executables for a lightweight ARM-Cortex M3 target.

  • 12.
    Lindner, Andreas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    RTFM-RT: a threaded runtime for RTFM-core towards execution of IEC 614992015In: Proceedings of 2015 IEEE 20th International Conference on Emerging Technologies & Factory Automation (ETFA 2015): Luxembourg, 8-11 Sept. 2015, Piscataway, NJ: IEEE Communications Society, 2015, 7301501Conference paper (Refereed)
    Abstract [en]

    The IEC 61449 standard provides an outset for designing and deploying distributed control systems. Recently, a mapping from IEC 61499 to the RTFM-kernel API has been presented. This allows predictable real-time execution of IEC 61499 applications on light-weight single-core platforms. However, integrating the RTFM-kernel (bare-metal runtime) into potential deployments requires developing device drivers, protocol stacks, and the like. For this presentation, we apply the mapping from IEC 61499 to the RTFM-MoC task and resource modelimplementedbytheRTFM-corelanguage.Thecompilation from RTFM-core can be targeted to both, RTFM-kernel and the introduced runtime system RTFM-RT. In this paper, we detail thegenericRTFM-RTruntimearchitecture,whichallowsRTFMcore programs to be executed on top of thread based environments. Furthermore, we discuss our implementation regarding scheduling specifics of Win32 threads (Windows) and Pthreads (Linux and Mac OS X). Using our RTFM-RT implementation for deployment,predictableIEC61499executiontogetherwithaccess to abovementioned operating system functions are achieved. For further developments, we discuss the needed scheduling options to achieve hard real-time and analysis required to eliminate deadlocks.

  • 13.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    Well formed Control-flow for Critical Sections in RTFM-core2015In: IEEE International Conference on Industrial Informatics: INDIN 2015, Cambridge, UK, July 22-24, 2015. Proceedings, Piscataway, NJ: IEEE Communications Society, 2015, 1438-1445 p., 7281944Conference paper (Refereed)
    Abstract [en]

    The mainstream of embedded software development as of today is dominated by C programming. To aid the development, hardware abstractions, libraries, kernels and lightweight operating systems are commonplace. Such kernels and operating systems typically impose a thread based abstraction to concurrency. However, in general thread based programming is hard, plagued by hazards of race conditions and dead-locks. For this paper we take an alternative outset in terms of a language abstraction, RTFM-core, where the system is modelled directly in terms of tasks and resources. In compliance to the Stack Resource Policy (SRP) model, the language enforces (well formed) LIFO nesting of claimed resources, thus SRP based analysis and scheduling can be readily applied. For the execution onto bare-metal single core architectures, the rtfm-core compiler performs SRP analysis on the model, and render an executable that is deadlock free and (through RTFM-kernel primitives) exploits the underlying interrupt hardware for efficient scheduling. The RTFM-core language embeds C-code and links to C-object files and libraries, and is thus applicable to the mainstream of embedded development. However, while the language enforces well formed resource management, control flow in the embedded C-code may violate the LIFO nesting requirement, thus correctness is left with the programmer to ensure well formed nesting (through restricted control flow). In this paper we address this issue by lifting a subset of C into the RTFM-core language allowing arbitrary control flow at the model level. In this way well formed LIFO nesting can be enforced, and models ensured to be correct by construction. We demonstrate the feasibility trough a prototype implementation in the rtfm-core compiler. Additionally, we develop a set of running examples, and show in detail how control flow is handled at compile time and during run-time execution.

  • 14.
    Ekman, Jonas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Borg, Johan
    Johansson, Jonny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    De Lauretis, Maria
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nilsson, Joakim
    Projekt: Frekvensomriktares funktion i beredskapskritiska system2014Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Vid dödnätstart av produktionsanläggningar och drift av svaga nät eller ö-drift är frekvensomriktare som driver pumpar och fläktar kritiska komponenter. Om frekvensomriktare påverkas av störningar i nätet kan elproduktion kopplas bort och det svaga nätet eller ö-driften kollapsa. Projektet ska studera frekvensomriktare ur ett antal aspekter såsom uppbyggnad, styrning och implementering i syfte att utveckla mer robusta frekvensomriktare och implementering av dessa för att säkerställa drift av svaga nät och ö-drift och minimera ytterligare driftstörningar vid svåra påfrestningar på elnätet.

  • 15.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Vyatkin, Valeriy
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Real-Time Execution of Function Blocks for Internet of Things using the RTFM-kernel2014In: Proceedings of 2014 IEEE 19th International Conference on Emerging Technologies & Factory Automation (ETFA 2014): Barcelona, Spain, 16-19 Sept. 2014, Piscataway, NJ: IEEE Communications Society, 2014, 1-6 p., 7005232Conference paper (Refereed)
    Abstract [en]

    Function Blocks provides a means to model andprogram industrial control systems. The recently acclaimed IEC61499 standard allows such system models to be partitioned andexecuted in a distributed fashion. At device level, such models aretraditionally implemented onto programmable logic controllersthat underneath have an operating system and a softwarerun-time environment which implies high resource demands.However, there is a current trend to involve small embeddedsystems (so called Internet of Things devices) integrated into suchdistributed control systems. To this end, we seek to address theoutsets for real-time execution of Function Block based designsonto light-weight controllers (MCUs) with limited resources(memory and CPU). Furthermore, we propose a mapping ofthe Function Block execution semantics onto the RTFM-kernel,and discuss opportunities for off-line (design time) analysis withrespect to response time, overall schedulability and memoryrequirements.

  • 16.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Vyatkin, Valeriy
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    RTFM-4-FUN2014In: 2014 9th IEEE International Symposium on Industrial Embedded Systems (SIES 2014): Pisa, 18-20 June 2014, Piscataway, NJ: IEEE Communications Society, 2014Conference paper (Refereed)
    Abstract [en]

    Function Blocks provides a means to model andprogram industrial control systems. The recently acclaimed IEC61499 standard allows such system models to be partitioned andexecuted in a distributed fashion. At device level, such models aretraditionally implemented onto programmable logic controllersand industrial PCs. In this paper, we discuss work in progresson developing a mapping allowing to implement a subset of IEC61499 models onto light-weight embedded devices (MCUs). Wepropose and detail an event semantics, and its mapping to thenotions of tasks and resources for Stack Resource Policy basedanalysis and scheduling. Moreover, we show how the proposedmapping can be efficiently implemented under the RTFM-kernel.Finally we outline a prototype tool-chain and discuss related,ongoing and future work.

  • 17.
    Lindner, Marcus
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    RTFM-core: Course in Compiler Construction2014In: Proceedings of the WESE'14: Workshop on Embedded and Cyber-Physical Systems Education, New York: ACM Digital Library, 2014, 4Conference paper (Refereed)
    Abstract [en]

    The course in Compiler Construction is part of the ComputerScience second cycle curriculum at Lulea Universityof Technology (LTU). Starting this year, the course is nowto be given by the Embedded Systems group at LTU. Thispaper outlines the course syllabus, and its relation to CPS/IoT and embedded systems in general. In particular, thecourse will now introduce domain specic language designwith the outset from the RTFM-core language. Studentswill be exposed to design choices for the language, spanningfrom programming model, compiler design issues, backendtools and even run-time environments. The intention is togive a holistic perspective, and motivate the use of compilationtechniques towards robust, ecient and veriable (embedded)software. Of course, developing basic skills will notbe overlooked, and as part of the laboratory assignments,students will extend the minimalistic Object Oriented languageRTFM-cOOre and develop the compiler accordinglytargeting the RTFM-core language as an intermediate representation.As the RTFM-core/-cOOre compilers are implementedunder OCaml/Menhir, the students will be exposedto the advantages of functional languages in the contextof compiler construction. However, for their own developmentthey may choose alternative design tools and languages(such as ANTLR/Java). This will give us the opportunityto review and correlate achievements and eciencyto the choice of tools and languages and be an outset forfuture course development.

  • 18.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Fresk, Emil
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    RTFM-core: Language and Implementation2014Conference paper (Refereed)
    Abstract [en]

    Robustness, real-time properties and resource eciency arekey properties to embedded devices of the CPS/IoT era. Inthis paper we propose a language approach RTFM-core,and show its potential to facilitate the development processand provide highly ecient implementations amendablefor static verication. Our programming model is reactive,based on the familiar notions of concurrent tasksand (single-unit) resources. The language is kept minimalistic,capturing the static task, communication and resourcestructure of the system. Whereas C-source can be arbitrarilyembedded in the model, and/or externally referenced,the instep to mainstream development is minimal, and asmooth transition of legacy code is possible. A prototypecompiler implementation for RTFM-core is presented. Thecompiler generates C-code output that compiled togetherwith the RTFM-kernel primitives runs on bare metal. TheRTFM-kernel guarantees deadlock-lock free execution andeciently exploits the underlying interrupt hardware forstatic priority scheduling and resource management underthe Stack Resource Policy. This allows a plethora of wellknownmethods to static verication (response time analysis,stack memory analysis, etc.) to be readily applied. The proposedlanguage and supporting tool-chain is demonstratedby showing the complete process from RTFM-core sourcecode into bare metal executables for a light-weight ARMCortexM3 target.

  • 19.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindner, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    RTFM-lang static semantics for systems with mixed criticality2014In: Ada User Journal, ISSN 1381-6551, Vol. 35, no 2, 128-132 p.Article in journal (Refereed)
    Abstract [en]

    In an embedded system, functions often operate under different requirements. In the extreme, a failing safety critical function may cause collateral damage (and hence consider to be a system failure) while non critical functions affect only the quality of service. Approaches by partitioning the system's functions into sandboxes require virtualization mechanisms by the underlying platform and thus prohibit deployment to the bulk of microcontroller based systems. In this paper we discuss an alternative approach based on static semantic analysis performed directly on the system specification expressed in the form of an object oriented (00) model in the experimental language RTFM-lang. This would allow to (at compile time) to discriminate in between critical and non-critical functions, and assign these (by means of statically checkable typing rules) appropriate access rights. In particular, one can imagine dynamic memory allocations to be allowed only in non-critical functions, while on the other hand, direct interaction with the environment may be restricted to the critical parts. With respect to scheduling, a static task and resource configuration allows e.g. Stack Resource Policy (SRP) based approaches to be deployed. In this paper we discuss how this can be achieved in a mixed critical setting.

  • 20.
    Ekman, Jonas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Johansson, Jonny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Borg, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Variable-Frequency Drives: Three perspectives2014Conference paper (Refereed)
  • 21.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Kyusakov, Rumen
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Mäkitaavola, Henrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pietrzak, Pawel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A SOA approach to delay and jitter tolerant distributed real-time complex event processing2013In: 2013 IEEE International Symposium on Industrial Electronics (ISIE 2013): Taipei, Taiwan, 28 - 31 May 2013; [proceedings], Piscataway, NJ: IEEE Communications Society, 2013Conference paper (Refereed)
    Abstract [en]

    The combination of Service Oriented Architectures (SOAs) and Complex Event Processing (CEP) is gaining momen- tum for event centric management and processing of informa- tion in complex distributed systems (e.g., business automation). Whereas systems for factory automation have traditionally been deployed using dedicated buses and proprietary (often scan based) protocols, a recent trend in process automation is towards adopting open internet based technologies and event based communication. This trend is driven by the increasing number and capabilities of devices used for monitoring and control, and the increased flexibility, maintainability and price/performance gains expected from IP (potentially SOA/CEP) enabled systems.In this paper we discuss the challenges involved to apply SOA and CEP to the field of factory automation. In particular, real- time aspects are highlighted, both w.r.t. to accurate time-stamping of physical events in a distributed system, as well as end-to-end timing including communication and CEP processing.We approach the challenges by an architecture combining state-of-the-art synchronisation mechanisms for wired and wire- less networks together with real-time communication and dis- tributed query processing based on the notion of time constrained reactions. We discuss the impact of synchronisation inaccuracies and delays introduced by processing and communication, and present a method for implementation of safe potential- and certain matches.

  • 22.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pietrzak, Pawel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Mäkitaavola, Henrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Real-time complex event processing using concurrent reactive objects2013In: Proceedings of the IEEE International Conference on Industrial Technology: ICIT 2013, Cape Town, South Africa 25 February 2013 - 28 February 2013, Piscataway, NJ: IEEE Communications Society, 2013, 1994-1999 p.Conference paper (Refereed)
    Abstract [en]

    Service Oriented Architectures (SOAs) and Complex Event Processing (CEP) are established technologies in the area of business automation. In combination, SOA and CEP allow for event centric management and processing of information in complex distributed systems. Whereas systems for process monitoring and control traditionally have been deployed using dedicated buses and proprietary (often scan-based) protocols, a recent trend in process automation is towards adopting open Internet-based technologies. This trend is driven by the increasing number and capabilities of devices used for monitoring and control

  • 23.
    Eriksson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Häggström, Fredrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Kruglyak, Andrey
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Real-time for the masses: Step 1: programming API and static priority SRP kernel primitives2013In: 2013 8th IEEE International Symposium on Industrial and Embedded Systems (SIES 2013): 19-21 June 2013, Porto, Portugal, Piscataway, NJ: IEEE Communications Society, 2013, 110-113 p.Conference paper (Refereed)
    Abstract [en]

    Lightweight Real-Time Operating Systems have gained widespread use in implementing embedded software on lightweight nodes. However, bare metal solutions are chosen, e.g., when the reactive (interrupt-driven) paradigm better matches the programmer’s intent, when the OS features are not needed, or when the OS overhead is deemed too large. Moreover, other approaches are used when real-time guarantees are required. Establishing real-time and resource guarantees typically requires expert knowledge in the field, as no turn-key solutions are available to the masses.In this paper we set out to bridge the gap between bare metal solutions and traditional Real-Time OS paradigms. Our goal is to meet the intuition of the programmer and at the same time provide a resource-efficient (w.r.t. CPU and memory) implementation with established properties, such as bounded memory usage and guaranteed response times. We outline a roadmap for Real-Time For the Masses (RTFM) and report on the first step: an intuitive, platform-independent programming API backed by an efficient Stack Resource Policy-based scheduler and a tool for kernel configuration and basic resource and timing analysis.

  • 24.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Mäkitaavola, Henrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Leveraging tinyos for integration in process automation and control systems2012In: IECON 2012: 38th Annual Conference of the IEEE Industrial Electronics Society, Piscataway, NJ: IEEE Communications Society, 2012, 5779-5785 p.Conference paper (Refereed)
    Abstract [en]

    The number and complexity of networked sensors and actuators in industrial monitoring and control systems is rapidly increasing. This calls for flexible yet efficient methods (w.r.t. time and money) for designing, deploying and maintaining such systems. To this end, Service Oriented Architectures (SOAs) and wireless technologies are foreseen to play important roles. In the area of Wireless Sensor Networks (WSNs), TinyOS (TOS) has gained wide spread use, mainly because it offers a simple programming model. Moreover TOS comes with a ready made code base (e.g., protocol stacks needed to implement SOA enabled devices) and is available for a large number of light-weight target platforms. However, TOS has yet to make its way into industrial applications where real-time operation is required (which is typical to monitoring and control systems). As being designed primarily with simplicity in mind, the TOS execution model for tasks is non-preemptive, limiting system responsiveness and schedulability. To overcome this problem preemptive TOSThreads has been introduced. However, this introduces the additional complexity of traditional multi-thread programming, thus the main benefit of TOS is lost. In this paper we present an alternative execution model for TOS, that allows preemptive execution while preserving the simplicity of vintage TOS. We exemplify the impact of scheduling to a typical sensor/actuator node scenario. Our results indicate that the proposed preemptive execution model is capable of reducing both delay and drop rate for the given scenario.

  • 25.
    Pietrzak, Pawel
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Mäkitaavola, Henrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Towards a lightweight CEP engine for embedded systems2012In: IECON 2012: 38th Annual Conference of the IEEE Industrial Electronics Society, Piscataway, NJ: IEEE Communications Society, 2012, 5805-5810 p.Conference paper (Refereed)
    Abstract [en]

    Industrial process automation systems are adopting event based communication. Pushing control loops towards low- level devices implies a need for lightweight embedded devices that are able to recognize and to react to events. Atomic events however, such as a value read by an individual sensor exceeding certain value, do not separately suffice to capture scenarios where a reaction should occur to a sequence of low-level events matching certain pattern, rather than to a single atomic event. Therefore, it becomes desirable that resource-constrained low- level devices are equipped with some, possibly lightweight, form of event filtering and processing. In this paper we propose to implement a lightweight complex event processing using the concurrent reactive objects (CRO) model. A core feature of the CRO model is its s ability to react to atomic events. Between the reactions, which basically are function executions, the system remains idle, and thus does not occupy the CPU and is energy-efficient. Additionally, CRO models can be executed in an efficient and predictable manner onto resource constrained platforms and offers low-overhead real-time scheduling through exploiting underlying interrupt hardware according to given time constraints.

  • 26.
    Wiklander, Jimmie
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    An IDE for component-based design of embedded real-time software2011In: 6th IEEE International Symposium on Industrial Embedded Systems (SIES), Piscataway, NJ: IEEE Communications Society, 2011, 47-50 p.Conference paper (Refereed)
    Abstract [en]

    This paper describes work in progress on a tool for component-based design of embedded real-time software. The tool supports graphical modeling of software systems using concurrent reactive objects and components, as well as generation of C code from the model. The resulting application code can then be combined with a lightweight kernel for execution on bare metal.

  • 27.
    Wiklander, Jimmie
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Kruglyak, Andrey
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Personal alarm device: a case study in component-based design of embedded real-time software2011Conference paper (Other academic)
    Abstract [en]

    Designing software for embedded systems is complicated by such factors as the tight integration between software and hardware, scarceness of available resources, and hard real-time requirements. In our earlier work we proposed a component-based approach based on modeling both hardware and software using reactive objects and time-constrained reactions, which should allow us to overcome these difficulties. We also presented a software design methodology for embedded real-time systems.Here we describe a system developed using this methodology and discuss its advantages. The system is a personal alarm device that should be worn at the waist of a person and that should detect his or her fall and send an alarm signal. The implementation of the system was verified using a Simulink-based simulator. The simulation demonstrated that, even though calculation of acceleration was simplified to allow for an efficient execution on a resource-constrained platform, fall detection remained satisfactory.The case study demonstrates the advantages of the proposed software design methodology, including the fact that functional and timing properties of a system model can be preserved during implementation process by means of a seamless transition between a model and an implementation.

  • 28.
    Eliasson, Jens
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pietrzak, Pawel
    Kyusakov, Rumen
    Project: Architecture for Service-Oriented Process – Monitoring and Control2011Other (Other (popular science, discussion, etc.))
  • 29.
    Pietrzak, Pawel
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Kyusakov, Rumen
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Roadmap for SOA event processing and service execution in real-time using Timber2011In: 2011 IEEE International Symposium on Industrial Electronics (ISIE 2011): Gdansk, Poland, 27 - 30 June 2011, Piscataway, NJ: IEEE Communications Society, 2011, 1727-1732 p.Conference paper (Refereed)
    Abstract [en]

    The introduction of Service Oriented Architectures for monitoring and control involves the deployment of SOA onto lightweight devices (e.g., embedded controllers for sensors and actuators). For the use of SOA in applications where timing and dependability are important, it becomes crucial that SOA event processing and service implementations are robust and time bound for a given platform. To this end, formalisms and tools aiding the design is instrumental. In this paper, we present a roadmap for a SOA based on components using the modeling and programming paradigm of Timber. Our vision is to present Timber based software components as services. By using current standards for service descriptions and eventing we will facilitate interoperability with legacy systems. We will develop a compiler tool suit allowing Timber based services to be deployable onto lightweight resource constrained platforms (e.g., sensors and actuators for industrial use). Our goal is to provide design time guarantees on e.g., robustness (safety and liveness), timing properties, and resource utilization for the complete embedded system comprising SOA event communication, event processing together with the service implementations.

  • 30.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pietrzak, Pawel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wiklander, Jimmie
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Scheduling of CRO systems under SPR-DM2011Conference paper (Refereed)
  • 31.
    Eriksson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wiklander, Jimmie
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Pietrzak, Pawel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    SRP-DM scheduling of component-based embedded real-time software2011Conference paper (Refereed)
    Abstract [en]

    Model and component based design is an established means for the development of large software systems, and is starting to get momentum in the realm of embedded software development. In case of safety critical (dependable systems) it is crucial that the underlying model and its realization captures the requirements on the timely behavior of the system, and that these requirements can be preserved and validated throughout the design process (from specification to actual code execution). To this end, we base the presented work on the notion of Concurrent Reactive Objects (CRO) and their abstraction into Reactive Components.In many cases, the execution platform puts firm resource limitations on available memory and speed of computations that must be taken into consideration for the validation of the system.In this paper, we focus on code synthesis from the model, and we show how specified timing requirements are preserved and translated into scheduling information. In particular, we present how ceiling levels for Stack Resources Policy (SRP) scheduling and analysis can be extracted from the model. Additionally, to support schedulability analysis, we detail algorithms that for a CRO model derives periods (minimum inter-arrival times) and offsets of tasks/jobs. Moreover, the design of a micro-kernel supporting cooperative hardware- and software-scheduling of CRO based systems under Deadline Monotonic SRP is presented.

  • 32.
    Wiklander, Jimmie
    et al.
    Luleå tekniska univesitet.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Utilizing an IDE for component-based design of embedded real-time software for an autonomous car2011Report (Other academic)
    Abstract [en]

    Embedded systems are inherently reactive and they often operate under resource and real-time constraints. Hence, a model supporting these fundamental properties is desirable for an efficient and correct design process. To this end, we have developed a component model and design methodology that enables component-based design of embedded software. Moreover, we have developed an Integrated Development Environment (IDE) that ensures a systematic development of software in accordance with the methodology.

    In this paper we review the IDE and it’s underlying modeling framework and demonstrate its applicability through a use-case with typical properties - a control system with real-time constraints and hardware interaction. This paper describes the whole design process – requirements specification, conceptual model, component-level design, component implementation, code synthesis, testing, and verification. In particular, we show how the modeling framework enforces a static component and communication structure reflecting the concurrent behavior of the system and its interaction with the environment (target platform).

    Our results (a working protoype) indicate applicability of the presented design approach, and show the IDE’s ability to generate efficient executables. Additionally, we show how to prove the schedulability of the target system in the IDE using standard scheduling theorems and machine assisted WCET measurements.

    In conclusion, this paper demonstrates both the applicability of the software design methodology and the functionality of the developed IDE.

  • 33. Borg, Johan
    et al.
    Hyyppä, Kalevi
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Projekt: ESIS2010Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Samlingsprojekt för alla ESIS-projekt

  • 34.
    Birk, Wolfgang
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Osipov, Evgeny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Riliskis, Laurynas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Road surface networks technology enablers for enhanced ITS2010In: 2010 IEEE Vehicular Networking Conference, VNC 2010: Jersey City, NJ ; 13-15 Dec 2010, Piscataway, NJ: IEEE Communications Society, 2010, 152-159 p.Conference paper (Refereed)
    Abstract [en]

    The increased need for mobility has led to transportation problems like congestion, accidents and pollution. In order to provide safe and efficient transport systems great efforts are currently being put into developing Intelligent Transport Systems (ITS) and cooperative systems. In this paper we extend proposed solutions with autonomous on-road sensors and actuators forming a wireless Road Surface Network (RSN). We present the RSN architecture and design methodology and demonstrate its applicability to queue-end detection. For the use case we discuss the requirements and technological solutions to sensor technology, data processing and communication. In particular the MAC protocol is detailed and its performance assessed through theoretical verification. The RSN architecture is shown to offer a scalable solution, where increased node density offers more precise sensing as well as increased redundancy for safety critical applications. The use-case demonstrates that RSN solutions may be deployed as standalone systems potentially integrated into current and future ITS. RSN may provide both easily deployable and cost effective alternatives to traditional ITS (with a direct impact independent of penetration rate of other ITS infrastructures - i.e., smart vehicles, safe spots etc.) as well as provide fine grain sensory information directly from the road surface to back-end and cooperative systems, thus enabling a wide range of ITS applications beyond current state of the art.

  • 35.
    Aittamaa, Simon
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Lindgren, Per
    Uniform scheduling of internal and external events under SRP-EDF2010In: Annual International Conference on Real-Time and Embedded Systems ( RTES 2010): 1-2 November 2010, Mandarin Orchard Hotel, Singapore, 2010Conference paper (Refereed)
    Abstract [en]

    With the growing complexity of modern embedded real-time systems, scheduling and managing of resources has become a daunting task. While scheduling and resource management for internal events can be simplified by adopting a commonplace real-time operating system (RTOS), scheduling and resource management for external events are left in the hands of the programmer, not to mention managing resources across the boundaries of external and internal events. In this paper we propose a unified system view incorporating earliest deadline first (EDF) for scheduling and stack resource policy (SRP) for resource management. From an embedded real-time system view, EDF+SRP is attractive not only because stack usage can be minimized, but also because the cost of a pre-emption becomes almost as cheap as a regular function call, and the number of preemptions is kept to a minimum. SRP+EDF also lifts the burden of manual resource management from the programmer and incorporates it into the scheduler. Furthermore, we show the efficiency of the SRP+EDF scheme, the intuitiveness of the programming model (in terms of reactive programming), and the simplicity of the implementation.

  • 36.
    Wiklander, Jimmie
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Kruglyak, Andrey
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Enabling component-based design for embedded real-time software2009In: Journal of Computers, ISSN 1796-203X, E-ISSN 1796-203X, Vol. 4, no 12, 1309-1321 p.Article in journal (Refereed)
    Abstract [en]

    The increasing complexity of embedded software calls for a new, more efficient design approach. A natural choice is to use well-established component-based design; however, its adoption to design of embedded software has been slow and riddled with difficulties. It can be argued that these problems are due to the following peculiarities of embedded systems. Firstly, the tight integration between hardware and software, typical for embedded systems, makes it virtually impossible to model and implement software separately from hardware. Secondly, it is difficult to express timing requirements, an intrinsic part of functionality of many embedded systems, in dataflow abstractions traditionally used in component-based design. We propose to overcome these difficulties by introducing a uniform, consistent modeling of both hardware and software and by integrating timing requirements into the model. We present a modeling framework based on the notions of reactive objects and time-constrained reactions, which enables component-based design of embedded real-time systems. Within this framework, functionality of both hardware and software components is defined in terms of reactions to discrete external events, and timing requirements are specified for each reaction relative to the event that triggered it. We also present a detailed software design methodology for embedded real-time systems based on our modeling framework.

  • 37. Johansson, Gustav
    et al.
    Johansson, Jonny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Öman, Joakim
    Sverige.
    Projekt: ESiS EP2009Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Sammanfattningsvis är forskningsmålet att optimera kretskortsproduktion för små och medelstora serier. Huvudsakligen handlar det om att undersöka och modellera det termiska systemet mellan kretskort och lödugn. Modellen kommer sedan att användas för att ge bättre konfigurationsparametrar för produktionslinjen. En bra modell kommer inte bara att öka lödningskvalitén och minska antalet kasserade kretskort men kan också även användas för att hitta avvikelser redan i kretskortsdesignen.

  • 38. Nybacka, Mikael
    et al.
    Larsson, Tobias
    Gylling, Arne
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Åhl, Anneli
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Projekt: Intelligenta inlandsvägen2009Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    VISION Genom samverkan med initiativtagare runt TSS-konceptet skall projektet ha bidragit till att göra E45’an till en europeisk ”Test Route”. Infrastrukturen skall erbjuda testmöjligheter av fordon i en mix av 2G, 3G, WLAN, WIMAX, NMT 450, o.s.v. Projektet skall skapa ett tydligt partnerskap mellan regionens entreprenörsdrivna mindre företag och de stora aktörerna inom två av svensk industris kärnområden (fordonsindustrin och telekomindustrin). BAKGRUND Centrum för Distansöverbryggande Teknik, ”CDT”, och Centre for Automotive system technology and Testing, CASTT, vid Luleå Tekniska Universitet, har den 1/1 2008 startat upp mål2-projektet ”den Intelligenta Inlandsvägen”. Övergripande mål är dels ett heterogent nät i form av en demomiljö med flera typer av transmissionstekniker, dels ett antal utvecklingsprojekt, med sikte på att bygga kunskap, teknik och metod som stödjer den vintertestrelaterade verksamheten inom denna demomiljö. PROJEKTSTRATEGI Ett samarbete med näringslivet både regionalt och nationellt skall säkra att framtagna prototyper tar sig ut på markanden som produkter och tjänster. Kopplingar till nationella projekt inom fordonsindustrin, inte minst Test Site Sweden, säkrar att utvecklingsinsatserna leder till ett vidgat nätverk för aktörerna inom vintertestregionen.

  • 39.
    Kangas, Maarit
    et al.
    University of Oulu.
    Vikman, Irene
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Wiklander, Jimmie
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nyberg, Lars
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Jämsä, Timo
    University of Oulu.
    Sensitivity and specificity of fall detection in people aged 40 years and over2009In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 29, no 4, 571-574 p.Article in journal (Refereed)
    Abstract [en]

    About one third of home-dwelling people over 65 years of age fall each year. Falling, and the fear of falling, is one of the major health risks that affects the quality of life among older people, threatening their independent living. In our pilot study, we found that fall detection with a waist-worn triaxial accelerometer is reliable with quite simple detection algorithms. The aim of this study was to validate the data collection of a new fall detector prototype and to define the sensitivity and specificity of different fall detection algorithms with simulated falls from 20 middle-aged (40-65 years old) test subjects. Activities of daily living (ADL) performed by the middle-aged subjects, and also by 21 older people (aged 58-98 years) from a residential care unit, were used as a reference. The results showed that the hardware platform and algorithms used can discriminate various types of falls from ADL with a sensitivity of 97.5% and a specificity of 100%. This suggests that the present concept provides an effective method for automatic fall detection.

  • 40.
    Eliasson, Jens
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A bluetooth-based sensor node for low-power ad hoc networks2008In: Journal of Computers, ISSN 1796-203X, E-ISSN 1796-203X, Vol. 3, no 5, 1-10 p.Article in journal (Refereed)
    Abstract [en]

    TCP/IP has recently taken promising steps toward being a viable communication architecture for networked sensor nodes. Furthermore, the use of Bluetooth can enable a wide range of new applications, and in this article, an overview of the performance and characteristics of a networked sensor node based on TCP/IP and Bluetooth is presented. The number of Bluetooth-enabled consumer devices on the market is increasing, which gives Bluetooth an advantage compared to other radio technologies from an interoperability point of view. However, this excellent ability to communicate introduces disadvantages since neither TCP/IP nor Bluetooth were designed with resource-constrained sensor nodes in mind. We, however, argue that the constraints imposed by general purpose protocols and technologies can be greatly reduced by exploiting characteristics of the communication scheme in use and efficient and extensive use of available low-power modes. Furthermore, we claim that a Bluetooth-enabled networked sensor node can achieve an operating lifetime in the range of years using a total volume of less than 10 cm3. The Mulle Embedded Internet System (EIS), along with its advanced power management architecture, is presented as a case-study to support the claims.

  • 41.
    Kangas, Maarit
    et al.
    Department of Medical Technology, University of Oulu.
    Konttila, Antti
    Department of Medical Technology, University of Oulu.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Winblad, Ikka
    Department of Medical Technology, University of Oulu.
    Jämsä, Timo
    Department of Medical Technology, University of Oulu.
    Comparison of low-complexity fall detection algorithms for body attached accelerometers2008In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 28, no 3, 285-291 p.Article in journal (Refereed)
    Abstract [en]

    The elderly population is growing rapidly. Fall related injuries are a central problem for this population. Elderly people desire to live at home, and thus, new technologies, such as automated fall detectors, are needed to support their independence and security. The aim of this study was to evaluate different low-complexity fall detection algorithms, using triaxial accelerometers attached at the waist, wrist, and head. The fall data were obtained from standardized types of intentional falls (forward, backward, and lateral) in three middle-aged subjects. Data from activities of daily living were used as reference. Three different detection algorithms with increasing complexity were investigated using two or more of the following phases of a fall event: beginning of the fall, falling velocity, fall impact, and posture after the fall. The results indicated that fall detection using a triaxial accelerometer worn at the waist or head is efficient, even with quite simple threshold-based algorithms, with a sensitivity of 97-98% and specificity of 100%. The most sensitive acceleration parameters in these algorithms appeared to be the resultant signal with no high-pass filtering, and the calculated vertical acceleration. In this study, the wrist did not appear to be an applicable site for fall detection. Since a head worn device includes limitations concerning usability and acceptance, a waist worn accelerometer, using an algorithm that recognizes the impact and the posture after the fall, might be optimal for fall detection.

  • 42.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Hyyppä, Kalevi
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Comprehensive reactive real-time programming2008In: Hawaii International Conference on Education: 2008 Conference Proceedings, 2008, 1440-1448 p.Conference paper (Refereed)
  • 43.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    IP over CAN: transparent vehicular to infrastructure access2008In: 2008 Consumer Communications and Networking Conference: [IEEE CCNC 2008] ; Las Vegas, Nevada, 10 - 12 January 2008, Piscataway, NJ: IEEE Communications Society, 2008, 758-759 p.Conference paper (Refereed)
    Abstract [en]

    For the future we foresee each vehicle to feature wireless communication (to the Internet and/or other vehicles) over various technologies, e.g., UMTS/GPRS, and WLAN/WiFi. In this paper we show how access to such communication resources could be granted to individual components (CAN bus connected ECUs) in the car by allowing transparent data transport using the standardized Internet Protocol (IP). Our experiments show that a complete IP Over CAN implementation, providing both UDP and TCP transport over IP, running on an Atmel AT90CAN128 is capable of transfer speeds up to 200 kbits while using less than 2 kbytes of dynamic RAM.

  • 44. Kangas, Maarit
    et al.
    Wiklander, Jimmie
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wikman, Irene
    Nyberg, Lars
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Jämsä, Timo
    Sensorband fall detector prototype: validation through data collection and analysis2008In: 2nd International Symposium on Medical Information and Communications Technology: ISMICT'07. Proceedings, Oulu: University of Oulu, 2008Conference paper (Refereed)
  • 45.
    Lindgren, Per
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Aittamaa, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    TinyTimber, reactive objects in C for real-time embedded systems2008In: Proceedings, Design, Automation and Test in Europe: DATE '08 ; Munich, Germany, 10 - 14 March 2008 / [ed] Donatella Sciuto, New York: ACM Digital Library, 2008, 1382-1385 p.Conference paper (Refereed)
    Abstract [en]

    Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this paper we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber (TT). The TT kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into priorities. In this paper, the TT kernel design is presented and performance metrics are presented for a number of representative embedded platforms, ranging from small 8-bit to more potent 32-bit micro controllers. The resulting system runs on bare metal, completely free of references to external code (even C-lib) which provides a solid basis for further analysis. In comparison to a traditional thread based real-time operating system for embedded applications (FreeRTOS), TT has tighter timing performance and considerably lower code complexity. In conclusion, TinyTimber is a viable alternative for implementing embedded real-time applications in C today.

  • 46.
    Eriksson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nybacka, Mikael
    Larsson, Tobias
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Using Timber in a multi-body design environment to develop reliable embedded software2008In: Intelligent vehicle iniative (IVI) technology controls and navigation systems, 2008: [held during the SAE 2008 world congress, held April 14 - 17, 2008 in Detroit, Michigan, USA], Warrendale, Pa.: Society of Automotive Engineers, Incorporated , 2008Conference paper (Refereed)
    Abstract [en]

    A major challenge for the automotive industry is to reduce the development time while meeting quality assessments for their products. This calls for new design methodologies and tools that scale with the increasing amount and complexity of embedded systems in today's vehicles.In this paper we undertake an approach to embedded software design based on executable models expressed in the high-level modelling paradigm of Timber. In this paper we extend previous work on Timber with a multi-paradigm design environment, aiming to bridge the gap between engineering disciplines by multi-body co-simulation of vehicle dynamics, embedded electronics, and embedded executable models. Its feasibility is demonstrated on a case study of a typical automotive application (traction control), and its potential advantages are discussed, as highlighted below:shorter time to market through concurrent, co-operative distributed engineering, andreduced cost through adequate system design and dimensioning, andimproved efficiency of the design process through migration and reuse of executable software components, andreduced need for hardware testing, by specification verification on the executable model early in the design process, andimproved quality, by opening up for formal methods for verification.

  • 47.
    Eriksson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A comprehensive approach to design of embedded real-time software for controlling mechanical systems2007In: Asia Pacific Automotive Engineering Conference Technical Papers, Society of Automotive Engineers, Incorporated , 2007Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a comprehensive approach to design of embedded real-time software for electrically controlled mechanical systems in automotive applications. As a case study, we implement a Gear change and Clutch controller for a Formula SAE car. This includes a generic communication interface and protocol for CAN bus communication, I/O interfaces for A/D conversion and PWM output, together with a PID controller for clutch actuation. Under our framework, the embedded software is developed using Timber, a programming language and formalism that provides executable models for embedded real-time systems. The case study shows how a complete control system can be straightforwardly modeled, simulated and transformed into executable code. The system has been realized and tested onto a lightweight, 8-bit AVR-5, embedded platform. Compared to the raw C code design flow, the proposed framework has in our case study showed increased efficiency with respect to development time. We boldly conclude that our Timber based framework offers true "work with the work".

  • 48.
    Kero, Martin
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A correct and useful incremental copying garbage collector2007In: Proceedings of the the 2007 International Symposium on Memory Management: Québec, Canada, October 21 - 22, 2007, New York: ACM Digital Library, 2007, 129-140 p.Conference paper (Refereed)
    Abstract [en]

    Designing a garbage collector with real-time properties is a particularly difficult task, involving the construction of both an incremental run-time algorithm as well as methods enabling a priori reasoning about schedulability in two dimensions (time and memory usage in conjunction). In order to comply with such ambitious goals with any amount of formal rigor, a comprehensive understanding of the actual algorithm used is of course a fundamental requirement. In this paper we present a formal model of an incremental copying garbage collector, where each atomic increment is modeled as a transition between states of a heap process. Soundness of the algorithm is shown by proving that the garbage collecting heap process is weakly bisimilar to a non-collecting heap with infinite storage space. In addition, we show that our collector is both terminating and useful, in the sense that it actually recovers the unreachable parts of any given heap in a finite number of steps.

  • 49.
    Eriksson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    van Deventer, Jan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A distributed engine management system for formula SAE2007In: Electronic Engine Controls: [held during the SAE 2007 world congress, April 16 - 19, 2007, Cobo Center, Detroit, MI, USA], Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2007Conference paper (Refereed)
    Abstract [en]

    In this paper a distributed system for engine management is presented. The system is in use on the 2006 and 2005 Formula SAE cars from Luleå University of Technology. The purpose of building such a system from scratch is to have a comprehensive, predictable and easily extendable platform, giving the possibility to add extra features even at the racetrack. This allows the system to serve as a research platform for embedded real-time systems and vehicle dynamics. Another motivation is to get low weight on the complete system, and to integrate the electronics in such a way that the total cabling required will be minimal. The initial requirements are that the system should implement launch control, traction control, electric gear shift and clutch control. To control the engine the system must implement sequential fuel injection, direct fire ignition and closed loop lambda control. Moreover to remotely tune and monitor the system parameters in real-time - even on the racetrack, the system should facilitate wireless communication. To achieve these goals a system consisting of five units communicating over a standard automotive bus (CAN1) was developed. In this paper we will describe the systems functionality and the units developed.

  • 50.
    Eliasson, Jens
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Thompson, Simon J.
    Monash University, Melbourne, VIC.
    Cheng, Yi-Bing
    Monash University, Melbourne, VIC.
    A power management architecture for sensor nodes2007In: IEEE Wireless Communications & Networking Conference: WCNC 2007 ; 11 - 15 March 2007, [Hong Kong], Piscataway, NJ: IEEE Communications Society, 2007, 3008-3013 p.Conference paper (Refereed)
    Abstract [en]

    Wireless sensor nodes are a versatile, generalpurpose technology capable of measuring, monitoring and controlling their environment. Even though sensor nodes are becoming ever smaller and more power efficient, there is one area that is not yet fully addressed; Power Supply Units (PSUs). Standard solutions that are efficient enough for electronic devices with higher power consumption than sensor nodes, such as mobile phones or PDAs, may prove to be ill suited for the extreme low-power and size requirements often found on wireless sensor nodes. In this paper, a system-level design of a Power Management Architecture (PMA) is presented. The PMA is an integration of PSU hardware and various software components, and is capable of supplying a sensor node with energy from multiple sources, as well as providing status information from the PSU. The heart of the architecture is a context- and power-aware Task manager, which controls when the nodes low-power modes are activated, and is highly integrated with PSU hardware as well as other software components in the system. Its main responsibility is to schedule when energy consuming tasks can be dispatched. Depending on the task priority and system configuration, a task can be either dispatched, discarded or delayed. This approach ensures that only critical tasks will be allowed to use the battery, and that the system will be powered by renewable energy when performing other non-critical tasks.

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