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  • 1.
    Aittamaa, Simon
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Lindgren, Per
    Uniform scheduling of internal and external events under SRP-EDF2010Inngår i: Annual International Conference on Real-Time and Embedded Systems ( RTES 2010): 1-2 November 2010, Mandarin Orchard Hotel, Singapore, 2010Konferansepaper (Fagfellevurdert)
    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.

  • 2.
    Aparicio Rivera, Jorge
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Heapless: Dynamic Data Structures without Dynamic Heap Allocator for Rust2018Inngår i: 2018 IEEE 16TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN), Piscataway, NJ: IEEE, 2018, s. 87-94, artikkel-id 8472097Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dynamic memory management is typically implemented using a global memory allocator, which may negatively impact the performance, reliability, and predictability of a program; in effect standards around safety-critical applications often discourage or even disallow dynamic memory management. This paper presents heapless, a collection of dynamic data structures (for vectors, strings, and circular buffers) that can be either stack or statically allocated, thus free of global allocator dependencies. The proposed data structures for vectors and strings closely mimic the Rust standard library implementations while adding support to gracefully handling cases of capacity exceedance. Our circular buffers act as queues and allowing channel like usage (by splitting). The Rust memory model together with the ability of local reasoning on memory requirements (brought by heapless) facilitates establishing robustness/safety guarantees and minimize attack surfaces of (industrial) IoT systems. We show that the heapless data structures are highly efficient and have predictable performance, thus suitable for hard real-time applications. Moreover, in our implementation heapless data structures are non-relocatable allowing mapping to hardware, useful, e.g., to DMA transfers. The feasibility, performance, and advantages of heapless are demonstrated by implementing a JSON serialization and de-serialization library for an ARM Cortex-M based IoT platform.

  • 3.
    Birk, Wolfgang
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Riliskis, Laurynas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Road surface networks technology enablers for enhanced ITS2010Inngår i: 2010 IEEE Vehicular Networking Conference, VNC 2010: Jersey City, NJ ; 13-15 Dec 2010, Piscataway, NJ: IEEE Communications Society, 2010, s. 152-159Konferansepaper (Fagfellevurdert)
    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.

  • 4.
    Blech, Jan Olaf
    et al.
    RMIT University, Melbourne.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pereira, David
    ISEP, Instituto Superior de Engenharia do Porto.
    Vyatkin, Valeriy
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zoitl, Alois
    fortiss GmbH, Munich.
    A Comparison of Formal Verification Approaches for IEC 614992016Inngår i: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA): Berlin, 6-9 Sept. 2016, Piscataway, NJ: IEEE conference proceedings, 2016, artikkel-id 7733636Konferansepaper (Fagfellevurdert)
    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

  • 5. Borg, Johan
    et al.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Projekt: ESIS2010Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Samlingsprojekt för alla ESIS-projekt

  • 6.
    Delsing, Jerker
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindblom, Jerry
    Sjölund, Daniel
    Luleå tekniska universitet.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Real time wireless measurement of mechanical data for a javelin throw2005Inngår i: Proceedings of the 13th Nordic-Baltic Conference of BioMedical Engineering and Medical Physics: NBC'05 / [ed] R Lundström; B Andersson; H Grip, Swedish Society for Medical Engineering and Medical Physics , 2005, s. 134-135Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Technology for the real time measurement of mechanical data from a javelin throw has been developed. The javelin is instrumented with an ineartial measurement unit measuring, IMU, acceleration, angle speed and direction to the earth magnetic field all in three dimensions i.e. in total nine parameters. The IMU is buildt into the javelin still maintaining the javelin properties and keeping it within the IAAF specifications. The instrumentation is build using the EIS architecture thus incorporating TCP/IP support including an Internet server. The wireless communication technology choosen is Bluetooth that connects to Internet through either a Bluetooth enabled mobile phone or a stationary Bluetooth accesspoint

  • 7.
    Delsing, Jerker
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Mobile Internet enabled sensors using mobile phones as access network2003Inngår i: Concurrent Engineering: the vision for the future generation in research and applications : proceedings of the 10th ISPE International Conference on Concurrent Engineering : research and applications / [ed] R. Jardim-Gonçalves; Jianzhong Cha; Adolfo Steiger-Garção, Lisse: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2003, s. 741-746Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We envision ambient intelligent environments with an infrastructure based on heterogeneous sensor and actuator devices accessible over the Internet. Initial steps to realize this concept have been taken by developing an Embedded Internet System (EIS) architecture for Internet protocol enabled devices. In many cases these devices will be in close proximity to a person. Such applications are found in for example sport and wellness. The mobile connection of such devices to the global Internet in a simple and cheap way is of particular interest. It is here proposed that such connection will make use of the existing and wide spread mobile phone networks. Since a few years most new mobile phones are equipped with Bluetooth technology making a mobile phone capable of connecting to 7 other Bluetooth devices. Thus by giving EIS devices a Bluetooth communication channel it will become possible to tunnel the EIS sensor communication through a mobile phone nearby the sensor. The proposed architecture will be described with discussion on limitations due to existing infrastructures and business models in the telecom networks.

  • 8.
    Delsing, Jerker
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Sensor communication technology towards ambient intelligence2005Inngår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 16, nr 4, s. R37-R46Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper is a review of the fascinating development of sensors and the communication of sensor data. A brief historical introduction is given, followed by a discussion on architectures for sensor networks. Further, realistic specifications on sensor devices suitable for ambient intelligence and ubiquitous computing are given. Based on these specifications, the status and current frontline development are discussed. In total, it is shown that future technology for ambient intelligence based on sensor and actuator devices using standardized Internet communication is within the range of possibilities within five years.

  • 9.
    Delsing, Jerker
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Östmark, Åke
    Mobile Internet enabled sensors using mobile phones as access network2004Inngår i: Electronic journal of information technology in construction, ISSN 1403-6835, E-ISSN 1400-6529, Vol. 9, nr Special Issue Mobile Computing in Construction, s. 381-388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We envision ambient intelligent environments with an infrastructure based on heterogeneous sensor and actuator devices accessible over the Internet. Initial steps to realize this concept have been taken by developing an Embedded Internet System (EIS) architecture for Internet protocol enabled devices. In many cases these devices will be in close proximity to a person. Such applications are found in for example sport and wellness. The mobile connection of such devices to the global Internet in a simple and cheap way is of particular interest. It is here proposed that such connection will make use of the existing and wide spread mobile phone networks. Since a few years most new mobile phones are equipped with Bluetooth technology making a mobile phone capable of connecting to 7 other Bluetooth devices. Thus by giving EIS devices a Bluetooth communication channel it will become possible to tunnel the EIS sensor communication through a mobile phone nearby the sensor. The proposed architecture will be described with discussion on limitations due to existing infrastructures and business models in the telecom networks.

  • 10.
    Dreschler, Rolf
    et al.
    Department of Computer Science, University of Bremen.
    Kerttu, Mikael
    Luleå tekniska universitet.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thornton, Mitchell
    Low-power optimization techniques for BDD mapped circuits using temporal correlation2002Inngår i: Canadian journal of electrical and computer engineering, ISSN 0840-8688, Vol. 27, nr 4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low-power optimization techniques for BDD mapped circuits using temporal correlation Techniques d'optimisation pour les faibles puissances pour des diagrammes de décision binaire utilisant la corrélation temporelle Rolf Drechsler, Mikael Kerttu, Per Lindgren, and Mitchell Thornton £ In modern design flows low-power aspects should be considered as early as possible to minimize power dissipation in the resulting circuit. A new binary decision diagram-based design style that considers switching activity optimization using temporal correlation information is presented. The technique is based on an approximation method for switching activity estimation. In the case of finite state machines, the presented method extracts signal statistics by means of Markov chain analyses. Experimental results on a set of MCNC and ISCAS89 benchmarks show the estimated reduction in power dissipation. Les aspects relatifs aux faibles puissances devraient être pris en compte dès les premières phases du design en vue de minimiser la dissipation de puissance du circuit résultant. Cet article présente une méthode de design basée sur un diagramme de décision binaire qui traite l'optimisation des commutations via l'information de corrélation temporelle. L'approche repose sur une approximation de l'estimation de l'activité decommutation. Dans le cas des machines àétats finis, la méthode extrait les statistiques du signal via une analyse par chaînes de Markov. Des résultats expérimentaux obtenus avec des données de banc d'essai MCNC et ISCAS89 montrent la réduction estimée de la dissipation de puissance

  • 11.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nilsson, Joakim
    Projekt: Frekvensomriktares funktion i beredskapskritiska system2014Annet (Annet (populærvitenskap, debatt, mm))
    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.

  • 12.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Variable-Frequency Drives: Three perspectives2014Konferansepaper (Fagfellevurdert)
  • 13.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Kyusakov, Rumen
    Project: Architecture for Service-Oriented Process – Monitoring and Control2011Annet (Annet (populærvitenskap, debatt, mm))
  • 14.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A bluetooth-based sensor node for low-power ad hoc networks2008Inngår i: Journal of Computers, ISSN 1796-203X, E-ISSN 1796-203X, Vol. 3, nr 5, s. 1-10Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 15.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thompson, Simon J.
    Monash University, Melbourne, VIC.
    Cheng, Yi-Bing
    Monash University, Melbourne, VIC.
    A power management architecture for sensor nodes2007Inngår i: IEEE Wireless Communications & Networking Conference: WCNC 2007 ; 11 - 15 March 2007, [Hong Kong], Piscataway, NJ: IEEE Communications Society, 2007, s. 3008-3013Konferansepaper (Fagfellevurdert)
    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.

  • 16.
    Eliasson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lundberg, Magnus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Time synchronous bluetooth sensor networks2006Inngår i: IEEE Consumer Communications and Networking Conference: CCNC 2006, Piscataway, NJ: IEEE Communications Society, 2006, s. 336-340Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Bluetooth-equipped wireless sensor nodes can be quickly integrated in small home networks. These networks can be utilized e.g. for surveillance, home monitoring and automation. Accurate time is an important factor for time-stamping of sensor data, encryption/authentication and it can also to used to implement time synchronous schemes for low power radio communication. We argue that IP-based time synchronization, such as various flavors of the NTP protocol, can be used with Bluetooth networks. This in combination with an activation schedule allows an efficient trade-off between energy consumption and communication delay, and provides easy integration with available infrastructure. The proposed approach in this paper is well suited for smaller wireless home networks, typically singlehop networks with access points that are always available. Our approach is verified by experiments performed on a COTS-based platform using Bluetooth.

  • 17.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    SRP-DM scheduling of component-based embedded real-time software2011Konferansepaper (Fagfellevurdert)
    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.

  • 18.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Häggström, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kruglyak, Andrey
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Real-time for the masses: Step 1: programming API and static priority SRP kernel primitives2013Inngår i: 2013 8th IEEE International Symposium on Industrial and Embedded Systems (SIES 2013): 19-21 June 2013, Porto, Portugal, Piscataway, NJ: IEEE Communications Society, 2013, s. 110-113Konferansepaper (Fagfellevurdert)
    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.

  • 19.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A comprehensive approach to design of embedded real-time software for controlling mechanical systems2007Inngår i: Asia Pacific Automotive Engineering Conference Technical Papers, Society of Automotive Engineers, Incorporated , 2007Konferansepaper (Fagfellevurdert)
    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".

  • 20.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A distributed engine management system for formula SAE2007Inngår i: 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 , 2007Konferansepaper (Fagfellevurdert)
    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.

  • 21.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nybacka, Mikael
    Larsson, Tobias
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Using Timber in a multi-body design environment to develop reliable embedded software2008Inngår i: 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 , 2008Konferansepaper (Fagfellevurdert)
    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.

  • 22.
    Hallberg, Josef
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Svensson, Sara
    Luleå tekniska universitet.
    Östmark, Åke
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Synnes, Kåre
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Enriched media-experience of sport events2004Inngår i: Proceedings: Sixth IEEE Workshop on Mobile Computing Systems and Applications, WMCSA 2004 : 2 - 3 December 2004, Windermere, Cumbria, United Kingdom, Los Alamitos, Calif: IEEE Communications Society, 2004, s. 2-9Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes a system where Internet-enabled sensor technology was integrated into a context-aware platform to give viewers of sport events an enriched media experience. The system was developed as a proof of concept and was evaluated during real-life use at the Vasaloppet cross-country ski event. Using Bluetooth wireless ad-hoc networking and GPRS technology, sensor data was transmitted from contestants to the context-aware platform Alipes, which in turn presented the sport event viewer with a personalized, context-aware view. In this paper we discuss the system architecture and integration of components. The system was evaluated both from technical and user perspectives, where the evaluation results confirm our approach to be technically feasible and that the system provide an enriched media-experience for the majority of viewers.

  • 23.
    Jennings, Glenn
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Isaksson, Joachim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ordered ternary decision diagrams and the multivalued compiled simulation of unmapped logic1994Inngår i: Proceedings: 27th Annual Simulation Symposium, April 11 - 15, 1994, La Jolla, California, Los Alamitos, Calif: IEEE Communications Society, 1994, s. 99-105Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We describe a method for generating logic simulation code which correctly responds to any number of undefined logic values at the code inputs. The method is based on our development of the ordered ternary decision diagram, itself based on Kleenean ternary logic, which explicitly and correctly manages the unknown logic value `U' in addition to the `1' and `0' of conventional OBDDs. We describe the OTDD and how to implement its reduction, application, and restriction operations. This method avoids expensive technology mapping, producing highly efficient `U'-correct compiled logic simulation code in seconds rather than in hours. Our experiments toward confirming the validity of the method are reported

  • 24.
    Jennings, Glenn
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Isaksson, Joachim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A state machine language supporting integer inequalities implemented with ordered ternary decision diagrams1994Inngår i: Proceedings, 1994 International Conference on Simulation and Hardware Description Languages: ICSHDL'94, Society for Computer Simulation , 1994Konferansepaper (Fagfellevurdert)
  • 25. Johansson, Gustav
    et al.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Öman, Joakim
    Sverige.
    Projekt: ESiS EP2009Annet (Annet (populærvitenskap, debatt, mm))
    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.

  • 26.
    Johansson, Jonny
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Völker, M.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Östmark, Åke
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Delsing, Jerker
    MULLE: a minimal sensor networking device: implementation and manufacturing challenges2004Inngår i: Proceedings: IMAPS Nordic annual conference 2004 : Helsingør, Denmark, September 26 - 28, 2004, Helsingør: International Microelectronics and Packaging Society, Nordic chapter , 2004, s. 265-271Konferansepaper (Fagfellevurdert)
  • 27.
    Kangas, Maarit
    et al.
    Department of Medical Technology, University of Oulu.
    Konttila, Antti
    Department of Medical Technology, University of Oulu.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    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 accelerometers2008Inngår i: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 28, nr 3, s. 285-291Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 28.
    Kangas, Maarit
    et al.
    University of Oulu.
    Vikman, Irene
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nyberg, Lars
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Jämsä, Timo
    University of Oulu.
    Sensitivity and specificity of fall detection in people aged 40 years and over2009Inngår i: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, ISSN 0966-6362, Vol. 29, nr 4, s. 571-574Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 29. Kangas, Maarit
    et al.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wikman, Irene
    Nyberg, Lars
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa och rehabilitering.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Jämsä, Timo
    Sensorband fall detector prototype: validation through data collection and analysis2008Inngår i: 2nd International Symposium on Medical Information and Communications Technology: ISMICT'07. Proceedings, Oulu: University of Oulu, 2008Konferansepaper (Fagfellevurdert)
  • 30. Kero, Martin
    et al.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Timber as an RTOS for small embedded devices2005Inngår i: PREALWSN 2005: proceedings of the First Workshop on Real-World Wireless Sensor Network : Stockholm, Sweden, 20-21 June 2005, Kista: Swedish Institute of Computer Science , 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Software development for small, real-time and resource constrained, embedded systems is becoming increasingly complex. To be able to guarantee robustness and reliability, the underlying infrastructure should not be based upon ad hoc solutions. In this paper we identify three key features of a minimalistic Real-Time Operating System (RTOS), and presents the run-time system of Timber, a reactive deadlinedriven programming language. We scrutinize the functionalities of the run-time system in the light of real-time requirements, and emphasize the importance of integrating an adequate notion of time, both semantically in the programming interface as well as part of the run-time system.

  • 31.
    Kero, Martin
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A correct and useful incremental copying garbage collector2007Inngår i: Proceedings of the the 2007 International Symposium on Memory Management: Québec, Canada, October 21 - 22, 2007, New York: ACM Digital Library, 2007, s. 129-140Konferansepaper (Fagfellevurdert)
    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.

  • 32.
    Kerttu, Mikael
    et al.
    Luleå tekniska universitet.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Thornton, Mitch
    Mississippi State University.
    Drechsler, Rolf
    University of Bremen.
    Switching activity estimation of finite state machines for low power synthesis2002Inngår i: Proceedings: 2002 IEEE International Symposium on Circuits and Systems : May 26 - 29, 2002, Fairmont Scottsdale Princess, Phoenix-Scottsdale, Arizona, U.S.A., Piscataway, NJ: IEEE Communications Society, 2002, s. 65-68Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A technique for computing the switching activity of synchronous finite state machine (FSM) implementations including the influence of temporal correlation among the next state signals is described. The approach is based upon the computation that a FSM is in a given state which, in turn, is used to compute the conditional probability that a next state bit changes given its present state value. All computations are performed using decision diagram (DD) data structures. As an application of this method, the next state activity information is utilized for low power optimization in the synthesis of binary decision diagram (BDD) mapped circuits. Experimental results are presented based on a set of the ISCAS89 sequential benchmarks showing an average power reduction of 40 percent and tip to 90 percent reduction for individual benchmarks on the estimated power dissipation.

  • 33.
    Leijon, Viktor
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    FIFO WiDOM: timely control over wireless links2007Inngår i: Proceedings of the 2007 IEEE Conference on Control Applications: Singapore, 1 - 3 October 2007 ; [part of IEEE Multi-Conference on Systems and Control, MSC], Piscataway, NJ: IEEE Communications Society, 2007, s. 1024-1030Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the idea of scheduling a control network in a first-come first-serve manner, and demonstrate a way to implement this over a wireless link. This achieves real-time guarantees and tightly bounded jitter for control applications. Further, how to design systems using this network is discussed, and the benefits compared to a standard priority MAC protocol are examined through simulations and a prototype implementation. The prototype is implemented using the reactive Timber programming model on a lightweight 8-bit platform.

  • 34.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Applications of decision diagrams in digital circuit design1999Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Design methodology of digital circuits is a rapidly changing field. In the last 20 years, the number of transistors on a single chip has increased from thousands to tens of millions. This sets new demands on the design tools involved, their ability to capture specifications on a high level, and finally synthesize them into hardware implementations. The introduction of Decision Diagrams (DDs) has brought new means towards solving many of the problems raised by the increasing complexity of todays designs. In this thesis, we study their use in VLSI CAD and develop a number of novel applications. Incomplete specifications are inherent to the functionality of almost all digital circuits. We present a design methodology providing a common basis between design validation and logic synthesis, namely the semantics of Kleenean Strong Ternary Logic. This is called upon as commonly used design methodologies, based e.g. on VHDL are shown to put design correctness in jeopardy. By an extension of DDs, we can efficiently represent and manipulate incompletely specified functions. The method presented, not only guarantees correctness of the final circuit, but also offers potential towards expressing and utilizing incompleteness in ways other methodologies are incapable of. The increasing density and speed of todays target technologies also changes the conditions for logic synthesis; e.g., traditional quality measures based on gate delays are becoming less accurate as delays caused by interconnections are raising their heads. To address this problem we propose methodologies allowing quality measures of the final circuit to be foreseen and considered throughout the whole synthesis process. In general this is a very hard task. We approach the problem by limiting our synthesis methodologies to those rendering regular layouts (Such as computational arrays and lattices). The regularity allows us to predict properties of the final circuit and at the same time, ensure design criteria to be met, e.g., path delays and routability of the final circuit. In this thesis, we develop new design methodologies and their algorithms. By our experimental results, they are shown to offer significant improvements to both state of the art two-level and multi-level based tools in the area of layout driven synthesis. Our minimization methods are based on Pseudo Kronecker Decision Diagrams (PKDDs) which are the most general type of ordered bitlevel diagrams for switching functions. In the thesis we elaborate on the properties of PKDDs and Ternary PKDDs (TPKDDs) and develop an efficient minimization method based on local variable exchange for TPKDDs. Furthermore, the problem of PKDD minimization is discussed and a number of different strategies are introduced and evaluated; the potential compactness of PKDDs is confirmed. The thesis spans from validation and verification of high-level specifications all the way down to layout driven synthesis, combining logic minimization, mapping and routing to the target architecture at hand. We conclude our work to offer new means towards solving many of the crucial problems occurring along the design process of modern digital circuits.

  • 35.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Dealing with imcompleteness in circuit design under Kleenean strong ternary logic1997Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 36.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Improved computational methods and lazy evaluation of the ordered ternary decision diagram1995Inngår i: Proceedings of the ASP-DAC '95, CHDL '95, VLSI '95, Asia and South Pacific Design Automation Conference, IFIP International Conference on Computer Hardware Description Languages and their Applications, IFIP International Conference on Very Large Scale Integration: August 29 - September 1, 1995, Makuhari Messe, Chiba, Japan, Tokyo, 1995, s. 379-384Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate the properties of the Ordered Ternary Decision Diagram (OTDD) in order to develop an efficient general OTDD package. The OTDD is a three-branched three-terminal diagram based on Kleenean strong ternary logic. The OTDD can represent functions having nontrivial don't-care sets in a single diagram and is capable of provably correct evaluation in the presence of unknown input values. We propose a number of improvements to both OTDD computational methods and data structures. Furthermore we introduce the purged form OTDD which unifies the abbreviated and full form OTDD into a single diagram. A package exploiting these OTDD specific properties is presented and we show the computational advantages of this improved package for LGSynth93 standard benchmarks.

  • 37.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Project: EIS Architecture Projects2007Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The EIS architecture group at EISLAB performs research on design methodologies, tools and realizations of Embedded Internet Systems. Key to our research is the concept of reactivity; reactivity in the sense that a system reacts to events, either internal to the system or caused by its environment. This is manifested through the modeling paradigm of Timber with the ultimate goal of low-power, robust, scalable, distributed systems, with formally established real-time properties. The reactive approach is applied throughout the system design, all the way from protocols for service discovery, Internet Protocol based communication, down to analog and digital sensor interfaces. By collaboration with the Mixed mode design group, the theoretical work can be demonstrated in real-world applications.•    EU FP6 SOCRADESIn the EU FP6 SOCRADES project, EISLAB investigatesarchitectures and protocols for real-time control over wireless links.•    The AmI LabEfficient code generation from Timber models.•    CASTTThrough the Center for Automotive Systems Technologies and Testing (CAST), Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. •    PhD PolisIn this bilateral Luleå-Oulo project, modular design of communication protocols is in focus. Ongoing work investigates how the Timber real-time semantics  and strong type system can be utilized towards modular software design with formally established real-time behavior. •    Intereg, Larmband – SensorbandTogether with Hälsovetenskap LTU, Caretech AB, Meri Lappi Institute, National Semiconductor  Kemi, and Medical Technology at Oulu University, a ultra low-power prototype system for fall detaction is being developed.

  • 38.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Symbolic cycle simulation with closure detection towards symbolic verification1996Inngår i: Proceedings of the Synthesis and System Integration of Mixed Technologies: SASIMI 96, 1996Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We describe the algorithms for symbolic cycle simulation of sequential designs containing hierarchies of icompletely specified functions and Boolean relations. We propose the SSTG (symbolic state transition graph), which captures both the propagation of unknown input values and the effect of icomplerteness in the specification, and we develop algorithms for SSTG closure detection. Input vectors can be presented as Boolean relations, both spatial and temporal, on previous sets of input vectors, internal states and output vectors. Moreover the SSTG can be used towards verifying the correctness of the design with repect to both synthesis and redesign.

  • 39.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    IP over CAN: transparent vehicular to infrastructure access2008Inngår i: 2008 Consumer Communications and Networking Conference: [IEEE CCNC 2008] ; Las Vegas, Nevada, 10 - 12 January 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 758-759Konferansepaper (Fagfellevurdert)
    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.

  • 40.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Becker, Bernd
    Decision diagram based minimization of pseudo Kronecker expressions2000Rapport (Annet vitenskapelig)
    Abstract [en]

    The problem of general 2-level AND/EXOR minimization is known to be hard and proposed heuristic methods tend to be time consuming. Pseudo Kronecker Expressions (PSDKROs) are an interesting subclass as an upper bound estimate of moderate size can be efficiently derived in many cases.

  • 41.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Becker, Bernd
    Improved minimization methods of pseudo Kronecker expressions for multiple output functions1998Inngår i: Proceedings: 1998 IEEE International Symposium on Circuits and Systems : May 31 - June 3, 1998, Monterey, California, Piscataway, NJ: IEEE Communications Society, 1998, s. 187-190Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Pseudo Kronecker expressions (PSDKROs) are a class of AND/EXOR expressions. For a Boolean function with a given variable order the minimal PSDKRO can be derived efficiently using decision diagram (DD) techniques. The quality, i.e., the number of products in the expression, of the result is known to be dependent on the variable ordering. This paper proposes several improvements and enhancements to previous minimization methods. A pruning technique that can be tuned to tradeoff quality for computational resources is presented. By applying dynamic ordering methods, significant improvements to many previously reported results are obtained. Furthermore, a new method for the minimization of multiple output functions is outlined. Experiments on a set of MCNC benchmarks confirm the advantages of the presented algorithms

  • 42.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Institute of Computer Science, Albert-Ludwigs-University.
    Becker, Bernd
    Institute of Computer Science, Albert-Ludwigs-University.
    Look-up table FPGA synthesis from minimized multi-valued pseudo Kronecker expressions1998Inngår i: Proceedings: 28th IEEE International Symposium on Multiple-Valued Logic, May 27 - 29, 1998, Fukuoka, Japan / [ed] Tsutomu Sasao; Bob Werner, Los Alamitos, Calif: IEEE Communications Society, 1998, s. 95-100Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we outline a method for Look-up Table-FPGA (LUT-FPGA) synthesis from minimized Multi-Valued Pseudo Kronecker Expressions (MV PSDKROs). By restricting logic minimization to consider only easily mappable expressions, a regular Cellular Architecture (CA) layout without routing overhead is obtained. In this way our method combines logic minimization, mapping and routing. The transformation into the MV domain reduces the area as the number of products in the PSDKRO expression can be further minimized. Deriving the exact minimum MV PSDKRO is known to be hard or even intractable. We address this by applying pruning techniques based on cost estimation and dynamic methods to find suitable variable orderings. Results on a set of MCNC benchmarks show the advantages of the proposed minimization methods

  • 43.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Institute of Computer Science, Albert-Ludwigs-University.
    Becker, Bernd
    Institute of Computer Science, Albert-Ludwigs-University.
    Synthesis of pseudo Kronecker lattice diagrams1999Inngår i: Proceedings: International Conference on Computer Design (ICCD '99) : 10 - 13 October 1999, Austin, Te, Los Alamitos, Calif: IEEE Communications Society, 1999, s. 307-310Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The design process of digital circuits is often carried out in individual steps, like logic minimization, mapping and routing. This leads to quality loss, e.g. in cases where highly optimized netlists fit badly onto the target architecture. Lattice diagrams have been proposed as one possible solution. They offer a regular two dimensional structure, thus overcoming the routing problem. However elegant, presented methods have only been shown to find practical lattice representations for small functions. We present heuristic synthesis methods for Pseudo-Symmetric Pseudo Kronecker Decision Diagrams (PSP-KDDs) applicable to incompletely specified multiple output functions. The lattice structure maps directly to both ASICs and fine grain FPGAs. Our method (combining logic minimization, mapping and routing) seeks to minimize area and delay by heuristic methods. Experimental results on a set of MCNC benchmarks show superior quality to previous methods and in many cases even optimal depth results for unfolded lattices

  • 44.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Becker, Bernd
    Synthesis of pseudo Kronecker lattice diagrams1999Inngår i: Proceedings. Reed-Muller99: International Workshop on Applications of the Reed-Muller Expansion in Circuit Design, 1999Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The design process of digital circuits is often carried out in individual steps, like logic minimization, mapping and routing. This leads to quality loss e.g., in cases where highly optimized netlists fit badly onto the target architecture. Lattice diagrams have been proposed as one possible solution. They offer a regular two dimensional structure, thus overcoming the routing problem. However elegant, presented methods have only shown to find practical lattice representations for small functions. We present heuristic synthesis methods for Pseudo-Symmetric Pseudo Kronecker Decision Diagrams (PSPKDDs) applicable to incompletely specified multiple output functions. The lattice structure maps directly to both ASICs and fine grain FPGAs. Our method (combining logic minimization, mapping and routing) seeks to minimize area and delay by heuristic methods. Experimental results on a set of MCNC benchmarks show superior quality to previous methods and in many cases even optimal depth results for unfolded lattices.

  • 45.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Drechsler, Rolf
    Albert-Ludwigs-University, Freiburg.
    Becker, Berndt
    Albert-Ludwigs-University, Freiburg.
    Minimization of ordered pseudo Kronecker decision diagrams2000Inngår i: Proceedings, 2000 International Conference on Computer Design: 17 - 20 September 2000, Austin, Texas, Los Alamitos, Calif: IEEE Communications Society, 2000, s. 504-510Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The introduction of Decision Diagrams (DDs) has brought new means towards solving many of the problems involved in digital circuit design. Compactness of the representation is one key issue. Ordered Pseudo Kronecker Decision Diagrams (OPKDDs) together with the use of complemented edges is known to offer the most general ordered read-once DD representation at the bit-level, hence OPKDDs hold all minimal sized bit-level ordered DDs for a given function. This representation allows us to trade-off diagram canonicity against compactness. Ternary-OPKDDs (TOPKDDs) implicitly holds all OPKDDs for a given variable order. We state the canonicity criteria for TOPKDDs having complemented edges and develop an efficient sifting based method for their minimization. Furthermore, a heuristic minimization algorithm for OPKDDs is devised, utilizing the redundancies of Ternary-OPKDDs (TOPKDDs). Experiments on a set of MCNC benchmarks confirm the potential compactness of OPKDDs and demonstrate the efficiency of the proposed heuristics.

  • 46.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Scheduling of CRO systems under SPR-DM2011Konferansepaper (Fagfellevurdert)
  • 47.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    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 Ethernet2015Inngår i: IEEE International Conference on Industrial Informatics: INDIN 2015, Cambridge, UK, July 22-24, 2015. Proceedings, Piscataway, NJ: IEEE Communications Society, 2015, s. 1206-1212, artikkel-id 7281907Konferansepaper (Fagfellevurdert)
    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.

  • 48.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    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 Ethernet2017Inngår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 13, nr 1, s. 287-297Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 49.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    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 criticality2014Inngår i: Ada User Journal, ISSN 1381-6551, Vol. 35, nr 2, s. 128-132Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 50.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Fresk, Emil
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    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 MCUs2016Inngår i: Vol. 13, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    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.

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