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  • 151.
    Neander, Jonas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Hansen, Ewa
    Mälardalen University, Department of Computer Science and Electronics.
    Mäki-Turja, Jukka
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Björkman, Mats
    Mälardalen University, Department of Computer Science and Electronics.
    A TDMA scheduler for the AROS architecture2006Report (Other academic)
    Abstract [en]

    In this paper we present a Time Division Multiple Access (TDMA) scheduler for the Asymmetric communication and ROuting in Sensor networks architecture (AROS). The scheduler enables dynamic network configurations of the AROS architecture. We show that asymmetric multihop communication with dynamic network configurations in AROS prolongs the lifetime of sensor nodes in long distance networks compared to the LEACH architecture.

  • 152.
    Neander, Jonas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Hansen, Ewa
    Mälardalen University, Department of Computer Science and Electronics.
    Mäki-Turja, Jukka
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Björkman, Mats
    Mälardalen University, Department of Computer Science and Electronics.
    Prolonging Network Lifetime in Long Distance Sensor Networks using a TDMA Scheduler2007In: Real-Time in Sweden – (RTiS’07), Västerås, Sweden, 2007Conference paper (Refereed)
    Abstract [en]

    In this paper we present a Time Division Multiple Access (TDMA) scheduler for the Asymmetric communication and ROuting in Sensor networks architecture (AROS). The scheduler enables dynamic network reconfigurations of the AROS architecture.

  • 153.
    Neander, Jonas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Hansen, Ewa
    Mälardalen University, Department of Computer Science and Electronics.
    Mäki-Turja, Jukka
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Björkman, Mats
    Mälardalen University, Department of Computer Science and Electronics.
    Prolonging Network Lifetime in Long Distance Sensor Networks using a TDMA Scheduler2006Conference paper (Refereed)
    Abstract [en]

    In this paper we present a Time Division Multiple Access (TDMA) scheduler for the Asymmetric communication and ROuting in Sensor networks architecture (AROS). The scheduler enables dynamic network reconfigurations of the AROS architecture.

  • 154.
    Neander, Jonas
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Björkman, Mats
    Mälardalen University, Department of Computer Science and Electronics.
    Svensson, Stefan
    ABB AB, Västerås, Sweden .
    Lennvall, Tomas
    ABB AB, Västerås, Sweden .
    Wireless Vibration Monitoring (WiVib) - An Industrial Case Study2007In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2007, p. 920-923Conference paper (Refereed)
    Abstract [en]

    Testing in realistic environments is often overlooked in the early development of new technology. This paper describes a test to evaluate the whole chain from an accelerometer mounted on a motor to a sensor node sending wireless data to an access point. A pilot gives a great opportunity to get input from end-users (which could be very useful at the initial stages of a project), and provide potential contacts for next pilots.

    The goal of the pilot was to get a better understanding of the targeted environment and possible interference It may also lead to the discovery of issues not yet thought of, issues important for the resulting design of the end product.

  • 155.
    Nemati, Farhang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Towards Resource Sharing by Message Passing among Real-Time Components on Multi-cores2011In: 2011 IEEE 16th International Conference on Emerging Technology and Factory Automation, ETFA 2011,Toulouse, France; 5 September 2011 through 9 September 2011, Toulouse, France, 2011, p. 1-4Conference paper (Refereed)
  • 156.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Hansson, Hans
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Punnekkat, Sasikumar
    Mälardalen University, School of Innovation, Design and Engineering.
    Timing Analysis of CAN-Based Automotive Communication Systems2008In: Automotive Embedded Systems Handbook, CRC Press, 2008Chapter in book (Other academic)
  • 157.
    Nolte, Thomas
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    A Synchronization Protocol for Temporal Isolation of Software Components in Vehicular Systems2009In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 5, no 4, p. 375-387Article in journal (Refereed)
    Abstract [en]

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

  • 158.
    Nyström, Dag
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nolin, Mikael
    Norström, Christer
    Snapshots in Real-Time Database using Database Pointer Transactions2005In: Proceedings - 11th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, 2005, p. 343-349Conference paper (Other academic)
    Abstract [en]

    We present 2V-DBP-SNAP an algorithm that allows hard real-time tasks in an embedded real-time control system to read a snapshot of a number of data elements in a real-time database. Furthermore, 2V-DBP-SNAP allows these data elements to be shared with soft real-time tasks, which access them using a database query language, and with other hard real-time tasks that use database pointers. 2V-DBP-SNAP allows temporal behavior and memory consumption to be accurately predicted. Introducing snapshot transactions is beneficial for embedded control-systems, such as for engine control in an automotive system, since a snapshot of the state of the environment can be collected, e.g., the state of all cylinders in the engine. 2V-DBP-SNAP is lightweight and predictable, both with respect to computational and memory overhead, and is therefore highly suited for resource constrained systems.

  • 159.
    Ouimet, Martin
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Lundqvist, Kristina
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    The Timed Abstract State Machine Language: An Executable Specification Language for Reactive Real-Time Systems2007In: Proceedings of the 15th International Conference on Real-Time and Network Systems (RTNS '07), 2007Conference paper (Refereed)
  • 160.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Corcoran, Diarmuid
    Ericsson Software Research.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Toward a Tailored Modeling of Non-Functional Requirements for Telecommunication Systems2011In: Proceedings - 2011 8th International Conference on Information Technology: New Generations, ITNG 2011, 2011, p. 1044-1045Conference paper (Refereed)
    Abstract [en]

    Addressing non-functional requirements in Real-Time Embedded Systems (RTES) is of critical importance. Proper functionality of the whole system is heavily dependent on satisfying these requirements. In model-based approaches for development of the systems in RTES domain, there are several methods and languages for modeling and analysis of non-functional requirements. However, in this domain there are different types of systems that have different sets of non-functionalrequirements. The problem is that the general modeling approaches for RTES may not cover all the needs of these sub domains such as telecommunication. In this poster paper, we suggest an approach to complement and apply general RTES modeling languages to better cover different non-functional requirements oftelecommunication systems.

  • 161.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    A methodology for designing energy-aware secure embedded systems2011In: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings, 2011, p. 87-90Conference paper (Refereed)
    Abstract [en]

    Bringing security aspects in earlier phases of development is one of the major shifts in software development trend. Model-driven development which helps with raising the abstraction level and facilitating earlier analysis and verification is a promising approach in this regard and there have been several efforts on modeling security aspects. However, the issue is that when it comes to embedded systems, non-functional requirements such as security are so interconnected that in order to satisfy one, trade-off analysis with other ones are necessary. Energy consumption is one of these requirements which is of great importance in embedded systems domain due to resource limitations that these systems have. In this paper, focusing on security and energy consumptions we propose a new methodology for model-driven design of embedded systems to bring energy measurements and estimations earlier in development phases and thus identify security design decisions that cause violations of specified energy requirements.

  • 162.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Design of Adaptive Security Mechanisms for Real-Time Embedded Systems2012In: Lecture Notes in Computer Science, vol. 7159, Eindhoven, The Netherlands: Springer, 2012, p. 121-134Chapter in book (Refereed)
    Abstract [en]

    Introducing security features in a system is not free and brings along its costs and impacts. Considering this fact is essential in the design of real-time embedded systems which have limited resources. To ensure correct design of these systems, it is important to also take into account impacts of security features on other non-functional requirements, such as performance and energy consumption. Therefore, it is necessary to perform trade-off analysis among non-functional requirements to establish balance among them. In this paper, we target the timing requirements of real-time embedded systems, and introduce an approach for choosing appropriate encryption algorithms at runtime, to achieve satisfaction of timing requirements in an adaptive way, by monitoring and keeping a log of their behaviors. The approach enables the system to adopt a less or more time consuming (but presumably stronger) encryption algorithm, based on the feedback on previous executions of encryption processes. This is particularly important for systems with high degree of complexity which are hard to analyze statistically. 

  • 163.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Enabling Trade-off Analysis of NFRs on Models of Embedded Systems2011In: 16th IEEE International Conference on Emerging Technology and Factory Automation (ETFA'11) , WiP session, Toulouse, France, 2011, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Satisfaction of Non-Functional Requirements (NFR), is a key factor in successful design of embedded systems. This is mainly due to the constraints and resource limitations in these systems. A design that cannot achieve functionality of the system under these limitations is actually a failure. Therefore, NFRs in design of embedded systems deserve special attention. However, one big issue is that NFRs are interconnected and cannot be considered in isolation; especially that they can have direct impacts on each other such as security and performance. This means that a careful balance and trade-off analysis among NFRs is necessary. In this paper, we focus on this need and identify what information about NFRs is required in order to perform trade-off analysis. We propose and explain our in-progress approach to incorporate this information into system models in order to enable trade-off analysis. Our approach is based on UML profiling method to annotate model elements with necessary information.

  • 164.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Model-Based Trade-off Analysis of Non-Functional Requirements: An Automated UML-Based Approach2013In: International Journal of Advanced Computer Science IJACSci, ISSN 2251-6379, Vol. 3, no 11, p. 575-588Article in journal (Refereed)
    Abstract [en]

    One common goal followed by software engineers is to deliver a product which satisfies the requirements of different stakeholders. Software requirements are generally categorized into functional and Non-Functional Requirements (NFRs). While NFRs may not be the main focus in developing some applications, there are systems and domains where the satisfaction of NFRs is even critical and one of the main factors which can determine the success or failure of the delivered product, notably in embedded systems. While the satisfaction of functional requirements can be decomposed and determined locally, NFRs are interconnected and have impacts on each other. For this reason, they cannot be considered in isolation and a careful balance and trade-off among them needs to be established. We provide a generic model-based approach to evaluate the satisfaction of NFRs taking into account their mutual impacts and dependencies. By providing indicators regarding the satisfaction level of NFRs in the system, the approach enables to compare different system design models and also identify parts of the system which can be good candidates for modification in order to achieve better satisfaction levels.

  • 165.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Modeling and Trade-off Analysis of NFRs2012Report (Other academic)
  • 166.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    On Generating Security Implementations from Models of Embedded Systems2011Conference paper (Refereed)
  • 167.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    On the Need for Extending MARTE with Security Concepts2011In: 2nd International Workshop on Model Based Engineering for Embedded Systems Design (M-BED 2011), Grenoble (France), 2011Conference paper (Refereed)
  • 168.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Toward Model-Based Trade-off Analysis of Non-Functional Requirements2012In: Proceedings - 38th EUROMICRO Conference on Software Engineering and Advanced Applications, SEAA 2012), 2012, p. 142-149Conference paper (Refereed)
    Abstract [en]

    In this paper we introduce a generic approach to analyze system design models with regard to the satisfaction of their Non-Functional Requirements (NFRs) to enable the evaluation of their NFRs' trade-offs. NFRs and their satisfaction become especially critical and deserve more attention in certain application domains such as real-time and embedded systems. This is mainly due to the constraints and resource limitations in these systems. A design that cannot achieve the functionality of the system under these limitations can mean a failure. However, one big issue is that NFRs are interconnected and cannot be considered in isolation as they can have direct impacts on each other like security and performance. This means that a careful balance and trade-off analysis among NFRs is necessary. In doing so, the role of functional parts that contribute and are implemented to satisfy an NFR should also be taken into account. We focus on these needs and identify what information about NFRs is required in order to perform trade-off analysis and comparison of design models. We propose and explain our approach to incorporate this information into system models using UML profiling method to annotate model elements with necessary information and then calculate satisfaction values of NFRs using model transformation technique.

  • 169.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    UML-Based Modeling of Non-Functional Requirements in Telecommunication Systems2011In: The Sixth International Conference on Software Engineering Advances (ICSEA 2011), Barcelona, Spain: The Institute of Electrical and Electronics Engineers, Inc. , 2011, p. 213-220Conference paper (Refereed)
    Abstract [en]

    Successful design of real-time embedded systems relies heavily on the successful satisfaction of their non-functional requirements. Model-driven engineering is a promising approach for coping with the design complexity of embedded systems. However, when it comes to modeling non-functional requirements and covering specific aspects of different domains and types of embedded systems, general modeling languages for real-time embedded systems may not be able to cover all of these aspects. One solution is to use a combination of modeling languages for modeling different non-functional requirements as is done in the definition of EAST-ADL modeling language for automotive domain. In this paper, we propose a UML-based solution, consisting of different modeling languages, to model non-functional requirements in telecommunication domain, and discuss different challenges and issues in the design of telecommunication systems that are related to these requirements.

  • 170.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Leveque, Thomas
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Managing Timing Implications of Security Aspects in Model-Driven Development of Real-Time Embedded Systems2012In: International Journal On Advances in Security, ISSN 1942-2636, Vol. 5, no 3/4, p. 68-80Article in journal (Refereed)
    Abstract [en]

    Considering security as an afterthought and addingsecurity aspects to a system late in the development processhas now been realized to be an inefficient and bad approach tosecurity. The trend is to bring security considerations as earlyas possible in the design of systems. This is especially criticalin certain domains such as real-time embedded systems. Due todifferent constraints and resource limitations that these systemshave, the costs and implications of security features should becarefully evaluated in order to find appropriate ones whichrespect the constraints of the system. Model-Driven Development(MDD) and Component-Based Development (CBD) are twosoftware engineering disciplines which help to cope with theincreasing complexity of real-time embedded systems. WhileCBD enables the reuse of functionality and analysis results bybuilding systems out of already existing components, MDD helpsto increase the abstraction level, perform analysis at earlierphases of development, and also promotes automatic codegeneration. By using these approaches and including securityaspects in the design models, it becomes possible to considersecurity from early phases of development and also identifythe implications of security features. Timing issues are one ofthe most important factors for successful design of real-timeembedded systems. In this paper, we provide an approach usingMDD and CBD methods to make it easier for system designersto include security aspects in the design of systems and identifyand manage their timing implications and costs. Among differentsecurity mechanisms to satisfy security requirements, our focusin this paper is mainly on using encryption and decryptionalgorithms and consideration of their timing costs to designsecure systems.

  • 171.
    Saadatmand, Mehrdad
    et al.
    Xdin Stockholm AB.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    On combining model-based analysis and testing2013In: Proceedings of the 2013 10th International Conference on Information Technology: New Generations, ITNG 2013, 2013, p. 260-266Conference paper (Refereed)
    Abstract [en]

    Testing a computer system is a challenging task, both due to the large number of possible test cases and the limited resources allocated for testing activities. This means that only a subset of all possible test cases can be chosen to test a system, and therefore the decision on the selection of test cases becomes important. The result of static analysis of a system can be used to help with this decision, in the context of model-based development of systems, this means that the analysis performed on a system model can be used to prioritize and guide the testing efforts. Furthermore, since models allow expression of non-functional requirements (such as performance, timing and security), model-guided testing can be used to direct testing towards specific parts of the system which have large impact on such requirements. In this paper, we focus on modeling and trade-off analysis of non-functional requirements and how static analysis helps to identify problematic parts of a system and thus guide the selection of test cases to target such parts. 

  • 172.
    Saadatmand, Mehrdad
    et al.
    XDIN AB, Stockholm, Sweden.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Testing of Timing Properties in Real-Time Systems: Verifying Clock Constraints2013In: Proceedings - Asia-Pacific Software Engineering Conference, APSEC, 2013, p. 152-152Conference paper (Refereed)
    Abstract [en]

    Ensuring that timing constraints in a real-time system are satisfied and met is of utmost importance. There are different static analysis methods that are introduced to statically evaluate the correctness of such systems in terms of timing properties, such as schedulability analysis techniques. Regardless of the fact that some of these techniques might be too pessimistic or hard to apply in practice, there are also situations that can still occur at runtime resulting in the violation of timing properties and thus invalidation of the static analyses' results. Therefore, it is important to be able to test the runtime behavior of a real-time system with respect to its timing properties. In this paper, we introduce an approach for testing the timing properties of real-time systems focusing on their internal clock constraints. For this purpose, test cases are generated from timed automata models that describe the timing behavior of real-time tasks. The ultimate goal is to verify that the actual timing behavior of the system at runtime matches the timed automata models. This is achieved by tracking and time-measuring of state transitions at runtime.

  • 173.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Towards Accurate Monitoring of Extra-Functional Properties in Real-Time Embedded Systems2012In: Asia-Pacific Software Engineering Conference, APSEC: Proceedings, 2012, p. 338-341Conference paper (Refereed)
    Abstract [en]

    Management and preservation of Extra-Functional Properties (EFPs) is critical in real-time embedded systems to ensure their correct behavior. Deviation of these properties, such as timing and memory usage, from their acceptable and valid values can impair the functionality of the system. In this regard, monitoring is an important means to investigate the state of the system and identify such violations. The monitoring result is also used to make adaptation and re-configuration decisions in the system as well. Most of the works related to monitoring EFPs are based on the assumption that monitoring results accurately represent the true state of the system at the monitoring request time point. In some systems this assumption can be safe and valid. However, if in a system the value of an EFP changes frequently, the result of monitoring may not accurately represent the state of the system at the time point when the monitoring request has been issued. The consequences of such inaccuracies can be critical in certain systems and applications. In this paper, we mainly introduce and discuss this practical problem and also provide a solution to improve the monitoring accuracy of EFPs.

  • 174.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Ul Mustafa, Naveed
    Royal Institute of Technology, KTH.
    Monitoring Capabilities of Schedulers in Model-Driven Development of Real-Time Systems2012In: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA 2012, 2012, p. Article number: 6489589-Conference paper (Refereed)
    Abstract [en]

    Model-driven development has the potential to reduce the design complexity of real-time embedded systems by increasing the abstraction level, enabling analysis at earlier phases of development, and automatic generation of code from the models. In this context, capabilities of schedulers as part of the underlying platform play an important role. They can affect the complexity of code generators and how the model is implemented on the platform. Also, the way a scheduler monitors the timing behaviors of tasks and schedules them can facilitate the extraction of runtime information. This information can then be used as feedback to the original model in order to identify parts of the model that may need to be re-designed and modified. This is especially important in order to achieve round-trip support for model-driven development of real-time systems. In this paper, we describe our work in providing such monitoring features by introducing a second layer scheduler on top of the OSE real-time operating system's scheduler. The goal is to extend the monitoring capabilities of the scheduler without modifying the kernel. The approach can also contribute to the predictability of applications by bringing more awareness to the scheduler about the type of real-time tasks (i.e., periodic, sporadic, and aperiodic) that are to be scheduled and the information that should be monitored and logged for each type.

  • 175.
    Saadatmand, Mehrdad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Ul Mustafa, Naveed
    School for Information and Communication Technology (ICT).
    The Role of Schedulers in Model-Driven Development of Real-Time Systems2012Report (Other academic)
    Abstract [en]

    Design of real-time embedded systems is a complex and challenging task. Model-driven development has the potential to reduce the design complexity of real-time embedded systems by increasing the abstraction level, enabling analysis at earlier phases of development, and automatic generation of code from the models. In this context, capabilities of schedulers as part of the underlying platform play an important role. They can affect the complexity of code generators and how the model is implemented on the platform. Also, the way a scheduler monitors timing behaviors of tasks and schedules them can facilitate extraction of runtime information. This information can then be used as feedback to the original model in order to identify parts of the model that may require to be re-designed and modified. In this paper, we describe our work in providing these features by introducing a second layer scheduler on top of OSE real-time operating system’s scheduler. The approach can also contribute to the predictability of systems by bringing more awareness to the scheduler about the type of real-time tasks (i.e., periodic, sporadic, and aperiodic) that are to be scheduled, and the information that should be monitored and logged for each type.

  • 176.
    Shin, Insik
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    On Optimal Hierarchical Resource Sharing in Open Environments2008Report (Other academic)
    Abstract [en]

    This paper presents a new perspective in the context of supporting logical resource sharing under hierarchical scheduling. Our work is motivated from a tradeoff between reducing resource holding times and reducing system load (i.e., the collective processor requirements to guarantee the schedulability of hierarchical scheduling frameworks). We formulate an optimization problem that determines the resource holding times of each individual tasks (and therefore those of subsystems) with the goal of minimizing the system load subject to the system's schedulability. We present efficient algorithms to find an optimal solution to the problem, and we prove their correctness. 

  • 177. Shin, Insik
    et al.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Synthesis of Optimal Interfaces for Hierarchical Scheduling with Resources 2008In: Proceedings of the 29th IEEE International Real-Time Systems Symposium (RTSS08)., 2008, p. 209-220Conference paper (Refereed)
    Abstract [en]

     

    This paper presents algorithms that (1) facilitate system independent synthesis of timing-interfaces for subsystems and (2) system-level selection of interfaces to minimize CPU load. The results presented are developed for hierarchical fixed-priority scheduling of subsystems that may share logical recourses (i.e., semaphores). We show that the use of shared resources results in a tradeoff problem, where resource locking times can be traded for CPU allocation, complicating the problem of finding the optimal interface configuration subject to schedulability. This paper presents a methodology where such a tradeoff can be effectively explored. It first synthesizes a bounded set of interface-candidates for each subsystem, independently of the final system, such that the set contains the interface that minimizes system load for any given  system. Then, integrating subsystems into a system, it finds the optimal selection of interfaces. Our algorithms have linear complexity to the number of tasks involved. Thus, our approach is highly suitable for adaptable and reconfigurable systems.

     

  • 178.
    Shin, Insik
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Behnam, Moris
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Towards Optimal Hierarchical Resource Sharing in Open Environments2007In: Proceedings of the Work-In-Progress (WIP) session of the 28th IEEE Real-Time Systems Symposium (RTSS'07), Tucson, AZ, USA, 2007, p. 57-60Conference paper (Refereed)
  • 179.
    Sjödin, Mikael
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Mäki-Turja, Jukka
    Mälardalen University, School of Innovation, Design and Engineering.
    Achieving Industrial Strength Timing Predictions of Embedded System Behavior2008In: Proceedings of the 2008 International Conference on Embedded Systems and Applications, ESA 2008, 2008, p. 173-178Conference paper (Refereed)
    Abstract [en]

    This paper discusses why the extensive scientific results on predicting embedded systems temporal behavior never, or very seldom, reaches the industrialcommunity. We also point out the main issues that the scientific community should focus on in order to facilitate industrial-strength timing predictions. The core problem is that the scientific community uses too simplistic or research oriented timing models. The models stemming from academy do not fit well with the structure of real systems. Thus, extracting a timing model that is amenable for analysis may prove prohibitively difficult. And even if a model can be extracted, it may not capture real system scenarios well. Thus, results from analyzing these models do not reflect real system behavior, leading to unnecessary pessimistic timingpredictions. In recent years, response-time analysis has matured to a degree where models can express complex system behaviors and analysis results are relatively tight with respect to real system behavior. However, in order to fully reach its potential, and be accepted by industry, several improvements of the technique are needed. First, behaviors that are commonly used in industrial systems (such as message passing and client/server-patterns) must be adequately captured by the timing models. Second, unnecessary pessimism in the analysis must be removed (i.e. the analysis results must correlate well with actual system behavior by providing minimal overestimation). Third, correlated behaviors of different parts of the systems must be accounted for (i.e. not all tasks will experience the worst case execution times at the same time).

  • 180. Sjödin, Peter
    et al.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Kjellberg, Mats
    CANopen.NET - Programming-less interconnection between GUI- and control-application2006In: International CAN Conference (iCC), Stockholm, 2006Conference paper (Refereed)
    Abstract [en]

    We present the novel concept CANopen.NET. In this concept we integrate Windows GUI-programming in .NET and control-applications based on CANopen. The integration is automated, thus no programming is needed.

    An increasing number of CAN-based systems are equipped with Windows-based graphical user-interfaces (GUIs). Today, the .NET framework provides the most attractive solutions for design of GUIs both i Windows and WindowsCE. However, transferring information between the CANopen-domain (which is typically unmanaged code) and the .NET-domain (managed code) is non trivial. Traditional methods require handwritten pieces of code both in the managed and unmanaged domain for each signal (object-dictionary entry). This means that adding or modifying signals to the system becomes tedious, error-prone and expensive.

    In .NET high-level abstractions like XML-documents, web-servers and databases are easily accessible and can be bound to graphical controls. Hence, in CANopen.NET we provide a .NET-database interface via the .NET type "dataset" to the data in the object dictionary. This dataset is automatically generated from a CANopen profile-specification (EDS-file). Also, the CANopen-stack is automatically configured from the EDS-file. Hence, CANopen.NET provides a programming-less interconnection between CANopen-based control-applications and Windows.NET-based GUI-applications. This significantly eases the development of CANopen-systems with GUIs.

  • 181.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Becker, Matthias
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Static Allocation of Parallel Tasks to Improve Schedulability in CPU-GPU Heterogeneous Real-Time Systems2019Conference paper (Refereed)
    Abstract [en]

    Autonomous driving is one of the main challenges of modern cars. Computer visions and intelligent on-board decision making are crucial in autonomous driving and require heterogeneous processors with high computing capability under low power consumption constraints. The progress of parallel computing using heterogeneous processing units is further supported by software frameworks like OpenCL, OpenMP, CUDA, and C++AMP. These frameworks allow the allocation of parallel computation on different compute resources. This, however, creates a difficulty in allocating the right computation segments to the right processing units in such a way that the complete system meets all its timing requirements. In this paper, we consider pre-runtime static allocations of parallel tasks to perform their execution either sequentially on CPU or in parallel using a GPU. This allows for improving any unbalanced use of GPU accelerators in a heterogeneous environment. By performing several heuristic algorithms, we show that the overuse of accelerators results in a bottle-neck of the entire system execution. The experimental results show that our allocation schemes that target a balanced use of GPU improve the system schedulability up to 90%.

  • 182.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Becker, Matthias
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Larsson, Marcus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Malardalen Univ, Sch Innovat Design & Engn, DPAC Res Profile, Vasteras, Sweden..
    Poster Abstract: Real-Time Capabilities of HSA Compliant COTS Platforms2016In: PROCEEDINGS OF 2016 IEEE REAL-TIME SYSTEMS SYMPOSIUM (RTSS), 2016, p. 364-364Conference paper (Refereed)
    Abstract [en]

    During recent years, the interest in using heterogeneous computing architecture in industrial applications has increased dramatically. These architectures provide the computational power that makes them attractive for many industrial applications. However, most of these existing heterogeneous architectures suffer from the following limitations: difficulties of heterogeneous parallel programming and high communication cost between the computing units. To overcome these disadvantages, several leading hardware manufacturers have formed the HSA Foundation to develop a new hardware architecture: Heterogeneous System Architecture (HSA). In this paper, we investigate the suitability of using HSA for real-time embedded systems. A preliminary experimental study has been conducted to measure massive computing power and timing predictability of HSA.

  • 183.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Intelligent Data Processing using In-Orbit Advanced Algorithms on Heterogeneous System Architecture2018In: IEEE Aerospace Conference 2018 IEEEAC2018, 2018, p. 1-8Conference paper (Refereed)
    Abstract [en]

    In recent years, commercial exploitation of small satellites and CubeSats has rapidly increased. Time to market of processed customer data products is becoming an important differentiator between solution providers and satellite constellation operators. Timely and accurate data dissemination is the key to success in the commercial usage of small satellite constellations which is ultimately dependent on a high degree of autonomous fleet management and automated decision support. The traditional way for disseminating data is limited by on the communication capability of the satellite and the ground terminal availability. Even though cloud computing solutions on the ground offer high analytical performance, getting the data from the space infrastructure to the ground servers poses a bottleneck of data analysis and distribution. On the other hand, adopting advanced and intelligent algorithms onboard offers the ability of autonomy, tasking of operations, and fast customer generation of low latency conclusions, or even real-time communication with assets on the ground or other sensors in a multi-sensor configuration. In this paper, the advantages of intelligent onboard processing using advanced algorithms for Heterogeneous System Architecture (HSA) compliant onboard data processing systems are explored. The onboard data processing architecture is designed to handle a large amount of high-speed streaming data and provides hardware redundancy to be qualified for the space mission application domain. We conduct an experimental study to evaluate the performance analysis by using image recognition algorithms based on an open source intelligent machine library 'MIOpen' and an open standard 'OpenVX'. OpenVX is a cross-platform computer vision library.

  • 184.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Using Docker in Process Level Isolation for Heterogeneous Computing on GPU Accelerated On-Board Data Processing Systems2019Conference paper (Refereed)
    Abstract [en]

    The technological advancements make the intelligent on-board data processing possible on a small scale of satellites and deep-space exploration spacecraft such as CubeSats. However, the operation of satellites may fall into critical conditions when the on-board data processing interferes strongly to the basic operation functionalities of satellites. In order to avoid these issues, there exist techniques such as isolation, partitioning, and virtualization. In this paper, we present an experimental study of isolation of on-board payload data processing from the basic operations of satellites using Docker. Docker is a leading technology in process level isolation as well as continuous integration and continuous deployment (CI/CD) method. This study continues with the prior study on heterogeneous computing method, which improves the schedulability of the entire system up to 90%. Based on this heterogeneous computing method, the comparison study has been conducted between the non-isolated and isolated environments.

  • 185.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Unibap AB, Uppsala, Sweden.
    A Trade-Off between Computing Power and Energy Consumption of On-Board Data Processing in GPU Accelerated Real-Time Systems2019Conference paper (Refereed)
    Abstract [en]

    On-board data processing is one of the prior on-orbit activities that it improves the performance capability of in-orbit space systems such as deep-space exploration, earth and atmospheric observation satellites, and CubeSat constellations. However, on-board data processing encounters with higher energy consumption compared to traditional space systems. Because traditional space systems employ simple processing units such as micro-controllers or a single-core processor as the systems require no heavy data processing on orbit. Moreover, solving the radiation hardness problem is crucial in space and adopting a new processing unit is challenging.

    In this paper, we consider a GPU accelerated real-time system for on-board data processing. According to prior works, there exist radiation-tolerant GPU, and the computing capability of systems is improved by using heterogeneous computing method. We conduct experimental observations of power consumption and computing potential using this heterogeneous computing method in our GPU accelerated real-time system.The results show that the proper use of GPU increases computing potential with 10-140 times and consumes between 8-130 times less energy. Furthermore, the entire task system consumes 10-65% of less energy compared to the traditional use of processing units.

  • 186.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Advancing On-Board Big Data Processing Using Heterogeneous System Architecture2018In: ESA/CNES 4S Symposium 4S 2018, 2018Conference paper (Refereed)
  • 187.
    Tsog, Nandinbaatar
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. ES (Embedded Systems).
    Bruhn, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Unibap AB, Sweden.
    Using Heterogeneous Computing on GPU Accelerated Systems to Advance On-Board Data Processing2019In: European Workshop on On-Board Data Processing 2019 OBDP2019, 2019Conference paper (Refereed)
  • 188.
    Yin, Hang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bril, Reinder J.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Formalization and verification of mode changes in hierarchical scheduling2014Conference paper (Refereed)
    Abstract [en]

    Hierarchical scheduling frameworks (HSFs) are a means for composing complex real-time embedded systems from independently developed and analyzed applications. To support multiple modes in a two-level HSF, the multi-mode adaptive hierarchical scheduling framework MMAHSF has recently been presented supporting different mode-change mechanisms. Currently, we provide a formalization and verification of mode changes in MMAHSF using the UPPAAL model checker for certain mode-change mechanisms. The verification indicates that MMAHSF and the proposed mode-change mechanisms are deadlock-free and guarantee mode changes in bounded time.

  • 189.
    Yin, Hang
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bril, Reinder J.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Formalization and verification of mode changes in hierarchical scheduling---An extended report2014Report (Other academic)
    Abstract [en]

    Hierarchical scheduling frameworks (HSFs) are a means for composing complex real-time embedded systems from independently developed and analyzed applications. To support multiple modes in a two-level HSF, the multi-mode adaptive hierarchical scheduling framework MMAHSF has recently been presented supporting different mode-change mechanisms. Currently, we provide a formalization and verification of mode changes in MMAHSF using the UPPAAL model checker for certain mode-change mechanisms. The verification indicates that MMAHSF and the proposed mode-change mechanisms are deadlock-free and guarantee correct mode changes in bounded time.

  • 190.
    Åkerholm, Mikael
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Carlson, Jan
    Mälardalen University, Department of Computer Science and Electronics.
    Fredriksson, Johan
    Mälardalen University, Department of Computer Science and Electronics.
    Hansson, Hans
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Håkansson, John
    Mälardalen University, Department of Computer Science and Electronics.
    Pettersson, Paul
    Mälardalen University, Department of Computer Science and Electronics.
    Handling Subsystems using the SaveComp Component Technology2006In: Workshop on Models and Analysis for Automotive Systems (WMAAS'06) in conjunction with the 27th IEEE Real-Time Systems Symposium (RTSS'06), Rio de Janeiro, Brazil, 2006Conference paper (Refereed)
  • 191.
    Åkerholm, Mikael
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Carlson, Jan
    Mälardalen University, Department of Computer Science and Electronics.
    Håkansson, John
    Uppsala University, Uppsala, Sweden.
    Hansson, Hans
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Pettersson, Paul
    Mälardalen University, Department of Computer Science and Electronics.
    The SaveCCM Language Reference Manual2007Report (Other academic)
    Abstract [en]

    This language reference describes the syntax and semantics of SaveCCM, a

    component modeling language for embedded systems designed with vehicle applications and safety concerns in focus. The SaveCCM component model was

    defined within the SAVE project. The SAVE components are influenced mainly

    by the Rubus component technology, with a switch concept similar to that

    in Koala. The semantics is defined by a transformation into timed automata

    with tasks, a formalism that explicitly models timing and real-time task scheduling.

    The purpose of this document is to describe a semantics of the SAVE component modeling language, which can be used to describe timing and functional behavior of components. The model of a system is in some cases an over approximation of the actual system behavior. An implementation of a model can resolve non-determinism e.g. by merging tasks or assigning a scheduling policy (such as static scheduling or fixed priority, preemptive or not) that will resolve

    the non-determinism.

  • 192.
    Åkerholm, Mikael
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Möller, Anders
    Hansson, Hans
    Nolin, Mikael
    Towards a Dependable Component Technology for Embedded System ApplicationsManuscript (Other academic)
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