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  • 351.
    Ermedahl, Andreas
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Sandberg, Christer
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Gustafsson, Jan
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Bygde, Stefan
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Lisper, Björn
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Loop Bound Analysis based on a Combination of Program Slicing, Abstract Interpretation, and Invariant Analysis2007Ingår i: OpenAccess Series in Informatics, Volume 6, 2007, 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    Static Worst-Case Execution Time (WCET) analysis is a technique to derive upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. A key component for static derivation of precise WCET estimates is upper bounds on the number of times different loops can be iterated. In this paper we present an approach for deriving upper loop bounds based on a combination of standard program analysis techniques. The idea is to bound the number of different states in the loop which can influence the exit conditions. Given that the loop terminates, this number provides an upper loop bound. An algorithm based on the approach has been implemented in our WCET analysis tool SWEET. We evaluate the algorithm on a number of standard WCET benchmarks, giving evidence that it is capable to derive valid bounds for many types of loops.

  • 352.
    Fahlén, Tony
    Mälardalens högskola, Akademin för innovation, design och teknik.
    En jämförande studie mellan Software-Defined Networking protokollen OpenFlow & OpFlex2017Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Software-Defined Networking är ett sätt att implementera ett nätverk som helt styrs från en central plats. Målet med SDN är att vara ett flexibelt nätverk som snabbt kan förändras för att klara av dagens massiva dataströmmar. För att SDN ska kunna fungera krävs det att ett protokoll används för att sköta kommunikationen mellan den centrala kontrollpunkten och nätverksutrustningen i nätverket. OpenFlow är ett sådant protokoll. OpenFlow protokollet är väl etablerat och används i många av dagens SDN-nätverk. Ett alternativ till detta är OpFlex, ett protokoll som är nytt på dagens marknad men har stöd från en mängd stora tillverkare i datavärlden. Målet med denna rapport är att jämföra dessa protokoll både teoretisk och även praktiskt via experiment i laborationsmiljö för att identifiera likheter och skillnader mellan protokollen. För att kunna jämföra dem utfördes först en omfattande litteraturstudie där information samlades in och sammanställdes om protokollen. Efter detta sattes en laborationsmiljö upp för att testa hur protokollen arbetar. Efter experimenten sammanställdes litteraturstudien och laborationsresultaten och protokollen bedömdes på olika områden. Slutligen lyftes olika situationer fram där respektive protokoll skulle lämpas att väljas över det andra.

  • 353.
    Falk, H.
    et al.
    Hamburg University of Technology, Germany.
    Altmeyer, S.
    University of Amsterdam, Amsterdam, Netherlands .
    Hellinckx, P.
    University of Antwerp, iMinds, Antwerp, Belgium.
    Lisper, Björn
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Puffitsch, W.
    Technical University of Denmark, Lyngby, Denmark.
    Rochange, C.
    University of Toulouse, Toulouse, France.
    Schoeberl, M.
    Technical University of Denmark, Lyngby, Denmark.
    Sørensen, R. B.
    Technical University of Denmark, Lyngby, Denmark.
    Wägemann, P.
    Friedrich-Alexander University Erlangen-Nürnberg, Erlangen-Nürnberg, Germany.
    Wegener, S.
    AbsInt Angewandte Informatik GmbH, Saarbrücken, Germany.
    TACLeBench: A benchmark collection to support worst-case execution time research2016Ingår i: OpenAccess Series in Informatics, 2016, s. 2.1-2.10Konferensbidrag (Refereegranskat)
    Abstract [en]

    Engineering related research, such as research on worst-case execution time, uses experimentation to evaluate ideas. For these experiments we need example programs. Furthermore, to make the research experimentation repeatable those programs shall be made publicly available. We collected open-source programs, adapted them to a common coding style, and provide the collection in open-source. The benchmark collection is called TACLeBench and is available from GitHub in version 1.9 at the publication date of this paper. One of the main features of TACLeBench is that all programs are self-contained without any dependencies on standard libraries or an operating system. 

  • 354. Fan, He
    et al.
    Xiong, Ning
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Big data stream learning based hybridized Kalman filter and backpropagation through time2017Ingår i: 13th International Conference on Natural Computation, Fuzzy Systems and Knowledge Discovery 2017 ICNC-FSKD-2017, 2017Konferensbidrag (Refereegranskat)
  • 355.
    Faragardi, H. R.
    et al.
    University of Innsbruck, Innsbruck, Austria.
    Vahabi, Maryam
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Fotouhi, Hossein
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Fahringer, T.
    University of Innsbruck, Innsbruck, Austria.
    An efficient placement of sinks and SDN controller nodes for optimizing the design cost of industrial IoT systems2018Ingår i: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024X, Vol. 48, nr 10, s. 1893-1919Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently, a growing trend has emerged toward using Internet of Things (IoT) in the context of industrial systems, which is referred to as industrial IoT. To deal with the time-critical requirements of industrial applications, it is necessary to consider reliability and timeliness during the design of an industrial IoT system. Through the separation of the control plane and the data plane, software-defined networking provides control units (controllers) coexisting with sink nodes, efficiently coping with network dynamics during run-time. It is of paramount importance to select a proper number of these devices (i.e., software-defined networking controllers and sink nodes) and locate them wisely in a network to reduce deployment cost. In this paper, we optimize the type and location of sinks and controllers in the network, subject to reliability and timeliness as the prominent performance requirements in time-critical IoT systems through ensuring that each sensor node is covered by a certain number of sinks and controllers. We propose PACSA-MSCP, an algorithm hybridizing a parallel version of the max-min ant system with simulated annealing for multiple-sink/controller placement. We evaluate the proposed algorithm through extensive experiments. The performance is compared against several well-known methods, and it is shown that our approach outperforms those methods by lowering the total deployment cost by up to 19%. Moreover, the deviation from the optimal solution achieved by CPLEX is shown to be less than 2.7%.

  • 356.
    Faragardi, Hamid Reza
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. hamid.faragardi@uibk.ac.at.
    Optimizing Timing-Critical Cloud Resources in a Smart Factory2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis addresses the topic of resource efficiency in the context of timing critical components that are used in the realization of a Smart Factory.The concept of the smart factory is a recent paradigm to build future production systems in a way that is both smarter and more flexible. When it comes to realization of a smart factory, three principal elements play a significant role, namely Embedded Systems, Internet of Things (IoT) and Cloud Computing. In a smart factory, efficient use of computing and communication resources is a prerequisite not only to obtain a desirable performance for running industrial applications, but also to minimize the deployment cost of the system in terms of the size and number of resources that are required to run industrial applications with an acceptable level of performance. Most industrial applications that are involved in smart factories, e.g., automation and manufacturing applications, are subject to a set of strict timing constraints that must be met for the applications to operate properly. Such applications, including underlying hardware and software components that are used to run the application, constitute a real-time system. In real-time systems, the first and major concern of the system designer is to provide a solution where all timing constraints are met. To do so we need a time-predictable IoT/Cloud Computing framework to deal with the real-time constraints that are inherent in industrial applications running in a smart factory. Afterwards, with respect to the time predictable framework, the number of required computing and communication resources can and should be optimized such that the deployed system is cost efficient. In this thesis, to investigate and present solutions that provide and improve the resource efficiency of computing and communication resources in a smart factory, we conduct research following three themes: (i) multi-core embedded processors, which are the key element in terms of computing components embedded in the machinery of a smart factory, (ii) cloud computing data centers, as the supplier of a massive data storage and a large computational power, and(iii) IoT, for providing the interconnection of computing components embedded in the objects of a smart factory. Each of these themes are targeted separately to optimize resource efficiency. For each theme, we identify key challenges when it comes to achieving a resource-efficient design of the system. We then formulate the problem and propose solutions to optimize the resource efficiency of the system, while satisfying all timing constraints reflected in the model. We then propose a comprehensive resource allocation mechanism to optimize the resource efficiency in the whole system while considering the characteristics of each of these research themes. The experimental results indicate a clear improvement when it comes to timing-critical IoT / Cloud Computing resources in a smart factory. At the level of multi-core embedded devices, the total CPU usage of a quad-core processor is shown to be improved by 11.2%. At the level of Cloud Computing, the number of cloud servers that are required to execute a given set of real-time applications is shown to be reduced by 25.5%. In terms of network components that are used to collect sensor data, our proposed approach reduces the total deployment cost of thesystem by 24%. In summary these results all contribute towards the realization of a future smart factory.

  • 357.
    Faragardi, Hamid Reza
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dehnavi, Saed
    University of Tehran, Iran.
    Kargahi, Mehdi
    University of Tehran, Iran.
    Papadopoulos, Alessandro
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    A Time-Predictable Fog-Integrated Cloud Framework: One Step Forward in the Deployment of a Smart Factory2018Ingår i: CSI International Symposium on Real-Time and Embedded Systems and Technologies REST'18, 2018, s. 54-62Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper highlights cloud computing as one of the principal building blocks of a smart factory, providing a huge data storage space and a highly scalable computational capacity. The cloud computing system used in a smart factory should be time-predictable to be able to satisfy hard real-time requirements of various applications existing in manufacturing systems. Interleaving an intermediate computing layer-called fog-between the factory and the cloud data center is a promising solution to deal with latency requirements of hard real-time applications. In this paper, a time-predictable cloud framework is proposed which is able to satisfy end-to-end latency requirements in a smart factory. To propose such an industrial cloud framework, we not only use existing real-time technologies such as Industrial Ethernet and the Real-time XEN hypervisor, but we also discuss unaddressed challenges. Among the unaddressed challenges, the partitioning of a given workload between the fog and the cloud is targeted. Addressing the partitioning problem not only provides a resource provisioning mechanism, but it also gives us a prominent design decision specifying how much computing resource is required to develop the fog platform, and how large should the minimum communication bandwidth be between the fog and the cloud data center.

  • 358.
    Faragardi, Hamid Reza
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Dehnavi, Saed
    University of Tehran, Iran.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Kargahi, Mehdi
    An Energy-Aware Time-Predictable Cloud Data CenterIngår i: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024XArtikel i tidskrift (Refereegranskat)
  • 359.
    Faragardi, Hamid Reza
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Univ Innsbruck, Innsbruck, Austria.
    Dehnavi, Saeid
    Univ Tehran, Sch Elect & Comp Engn, Coll Engn, Tehran, Iran..
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Kargahi, Mehdi
    Univ Tehran, Sch Elect & Comp Engn, Coll Engn, Tehran, Iran.;Inst Res Fundamental Sci IPM, Sch Comp Sci, Tehran, Iran..
    Fahringer, Thomas
    Univ Innsbruck, Inst Comp Sci, Distributed & Parallel Syst Grp, Innsbruck, Austria.
    An energy-aware resource provisioning scheme for real-time applications in a cloud data center2018Ingår i: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024X, Vol. 48, nr 10, s. 1734-1757Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on a pay-as-you-go model, cloud computing provides the possibility of hosting pervasive applications from both academic and business domains. However, data centers hosting cloud applications consume huge amounts of electrical energy, contributing to high operational costs and large carbon footprints to the environment. Energy-aware resource provisioning is an effective solution to diminish the energy consumption of cloud data centers. Recently, a growing trend has emerged, where cloud technology is used to run periodic real-time applications such as multimedia, telecommunication, video gaming, and industrial applications. In order for a real-time application to be able to use cloud services, cloud providers have to be able to provide timing guarantees. In this paper, we introduce an energy-aware resource provisioning mechanism for cloud data centers, which are capable of serving real-time periodic tasks following the Software as a Service model. The proposed method is compared against an energy-aware version of the RT-OpenStack. RT-OpenStack is a recently proposed approach to provide a time-predictable version of OpenStack. The experimental results manifest that our proposed resource provisioning method outperforms energy-aware version of the RT-OpenStack by 16.01%, 25.45%, and 25.45% in terms of energy consumption, number of used servers, and average utilization of used servers, respectively. Moreover, from the scalability perspective, the preference of the proposed method for large-scale data centers is more considerable.

  • 360.
    Faragardi, Hamid Reza
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lisper, Björn
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sandström, Kristian
    RISE SICS, Västerås, Sweden.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A resource efficient framework to run automotive embedded software on multi-core ECUs2018Ingår i: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, s. 64-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing functionality and complexity of automotive applications requires not only the use of more powerful hardware, e.g., multi-core processors, but also efficient methods and tools to support design decisions. Component-based software engineering proved to be a promising solution for managing software complexity and allowing for reuse. However, there are several challenges inherent in the intersection of resource efficiency and predictability of multi-core processors when it comes to running component-based embedded software. In this paper, we present a software design framework addressing these challenges. The framework includes both mapping of software components onto executable tasks, and the partitioning of the generated task set onto the cores of a multi-core processor. This paper aims at enhancing resource efficiency by optimizing the software design with respect to: 1) the inter-software-components communication cost, 2) the cost of synchronization among dependent transactions of software components, and 3) the interaction of software components with the basic software services. An engine management system, one of the most complex automotive sub-systems, is considered as a use case, and the experimental results show a reduction of up to 11.2% total CPU usage on aquad-core processor, in comparison with the common framework in the literature. 

  • 361.
    Faragardi, Hamid Reza
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rajabi, Aboozar
    University of Tehran, Tehran, Iran.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Heidarizadeh, Amir Hosein
    A Profit-aware Allocation of High Performance Computing Applications on Distributed Cloud Data Centers with Environmental Considerations2014Ingår i: CSI Journal on Computer Science and Engineering JCSE, Vol. 2, nr 1, s. 28-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Set of Geographically Distributed Cloud data centers (SGDC) is a promising platform to run a large number of High Performance Computing Applications (HPCAs) in a cost-efficient manner. Energy consumption is a key factor affecting the profit of a cloud provider. In a SGDC, as the data centers are located in different corners of the world, the cost of energy consumption and the amount of CO2 emission significantly vary among the data centers. Therefore, in such systems not only a proper allocation of HPCAs results in CO2 emission reduction, but it also causes a substantial increase of the provider's profit. Furthermore, CO2 emission reduction mitigates the destructive environmental impacts. In this paper, the problem of allocation of a set of HPCAs on a SGDC is discussed where a two-level allocation framework is introduced to deal with the problem. The proposed framework is able to reach a good compromise between CO2 emission and the providers' profit subject to satisfy HPCAs deadlines and memory constraints. Simulation results based on a real intensive workload demonstrate that the proposed framework enhances the CO2 emission by 17% and the provider's profit by 9% in average.

  • 362.
    Fard, Ali
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Johnson, Tord
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Åberg, Denny
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Design of a Dual-Band 5/2.5 GHz CMOS VCO for 802.11 a/b/g WLAN Radios2004Ingår i: Proceedings of Swedish System-on-Chip Conference (SSOC), 2004Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 363.
    Fatima, Rubia
    et al.
    Tsinghua University, China.
    Yasin, Affan
    Tsinghua University, China.
    Liu, Lin
    Tsinghua University, China.
    Wang, Jianmin
    Tsinghua University, China.
    Afzal, Wasif
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Yasin, Atif
    Improving Software Requirements Reasoning by Novices: An Empirical EvaluationIngår i: IET Software, ISSN 1751-8806, E-ISSN 1751-8814Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context: Requirements-elicitation is one of the essential steps towards software design and construction. Business analysts and stakeholders often face challenges in gathering or conveying key software requirements. There are many methods, and tools designed by researchers and practitioners, but with the invention of new technologies, there appears to be a need to make requirements gathering and design-rationale process more efficient. Storytelling is an emerging concept and researchers are witnessing its effectiveness in education, community-building, information system, and requirement elicitation. Objective: Objectives of this study are to i) devise a method for requirements elicitation and improving design-rationales using story-based technique; ii) evaluate the effectiveness of the aforementioned proposed activity. Methodology: To answer the research objectives, we have i) conducted open-ended interviews to get feedback on our proposed method; ii) case requirement from a running project to map how this method can be useful; and iii) performed empirical evaluation of the proposed card-based activity. Result: i) Our regression model has shown that participants' perception regarding the ease of use and the fun in the game has an ultimate effect on requirements elicitation through enhancing user's desire to play the game, hence, increasing the collaborative learning outcomes of the game; ii) Our results have shown that using team-based activities helps the less-experienced designers to argue through design rationales and better elicit software requirements. Our results have reinforced the finding that using game-based solutions not only enhances communication and develops trust between stakeholders but also helps in motivating participants of requirements activity; iii) Initial results (from interview and empirical evaluation) for the proposed technique and method show positive results. Improvement in the process and activity as suggested by the participants will be accommodated in future studies.

  • 364.
    Felderer, M.
    et al.
    University of Innsbruck, Innsbruck, Austria.
    Gurov, D.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Huisman, M.
    University of Twente, Enschede, Netherlands.
    Lisper, Björn
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Schlick, R.
    AIT Austrian Institute of Technology, Seibersdorf, Austria.
    Formal methods in industrial practice - Bridging the gap (track summary)2018Ingår i: Lect. Notes Comput. Sci., Springer Verlag , 2018, s. 77-81Konferensbidrag (Refereegranskat)
    Abstract [en]

    Already for many decades, formal methods are considered to be the way forward to help the software industry to make more reliable and trustworthy software. However, despite this strong belief, and many individual success stories, no real change in industrial software development seems to happen. In fact, the software industry is moving fast forward itself, and the gap between what formal methods can achieve, and the daily software development practice does not seem to get smaller (and might even be growing).

  • 365.
    Feljan, Juraj
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Carlson, Jan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Zagar, Mario
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Realizing a domain specific component model with JavaBeans2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    SaveCCM is a domain specific component model developed specifically for safety-critical hard real-time embedded systems. The goal of this paper is to extend the scope of SaveCCM to make it usable also outside this narrow domain, as the general concepts behind SaveCCM are applicable as well for embedded systems that have soft or no real-time constraints. We describe the modifications made to SaveCCM in order to adjust it to the wider scope, focusing on defining a new realization mechanism. In its original form, a SaveCCM system is realized by component allocation to real-time tasks, which means that individual components are not observable in the run-time system. We propose realizing SaveCCM by a transformation to JavaBeans, making the advantages of component-based development present also at run-time. This way we also make the executable system more general and portable.

  • 366.
    Feljan, Juraj
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ciccozzi, Federico
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Carlson, Jan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Crnkovic, Ivica
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Enhancing model-based architecture optimization with monitored system runs2015Ingår i: 41st Euromicro Conference on Software Engineering and Advanced Applications SEAA15, 2015, s. 216-233Konferensbidrag (Refereegranskat)
    Abstract [en]

    Typically, architecture optimization searches for good architecture candidates based on analyzing a model of the system. Model-based analysis inherently relies on abstractions and estimates, and as such produces approximations which are used to compare architecture candidates. However, approximations are often not sufficient due to the difficulty of accurately estimating certain extra-functional properties. In this paper, we present an architecture optimization approach where the speed of model-based optimization is combined with the accuracy of monitored system runs. Model-based optimization is used to quickly find a good architecture candidate, while optimization based on monitored system runs further refines this candidate. Using measurements assures a higher accuracy of the metrics used for optimization compared to using performance predictions. We demonstrate the feasibility of the approach by implementing it in our framework for optimizing the allocation of software tasks to the processing cores of a multicore embedded system.

  • 367.
    Fifo, Miraldi
    et al.
    Mälardalens högskola.
    Enoiu, Eduard Paul
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Afzal, Wasif
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    On Measuring Combinatorial Coverage of Manually Created Test Cases for Industrial Software2019Ingår i: International Conference on Software Testing, Verification and Validation Workshops ICSTW19, 2019, s. 264-267Konferensbidrag (Refereegranskat)
    Abstract [en]

    Combinatorial coverage has been proposed as a way to measure the quality of test cases by using the input interaction characteristics. This paper describes the results of empirically measuring combinatorial coverage of manually created test cases by experienced industrial engineers. We found that manual test cases achieve on average 78% 2-way combinatorial coverage, 57% 3-way coverage, 40% 4-way coverage, 20% 5-way combinatorial coverage and 13% for 6-way combinatorial coverage. These manual test cases can be augmented to achieve 100% combinatorial coverage for 2-way and 3-way interactions by adding eight and 66 missing tests on average, respectively. For 4-way interactions, full combinatorial coverage can achieved by adding 658 missing tests. For 5-way and 6-way interactions, full combinatorial coverage can be achieved by adding 5163 and 6170 missing tests on average, respectively. The results of this paper suggest that manual tests created by industrial engineers do no achieve high combinatorial coverage and can be improved by using combinatorial testing at the expense of the number of test cases to be executed.

  • 368.
    Filieri, Antonio
    et al.
    Imperial College London, UK.
    Maggio, Martina
    Lund University, Sweden.
    Angelopoulos, Konstantinos
    University of Brighton, UK.
    D'Ippolito, Nicolas
    Gerostatopoulos, Ilias
    Hempel, Andreas
    Jamshidi, Pooyan
    Kalyvianaki, Evangelia
    Klein, Cristian
    Umeå University, Sweden.
    Krikava, Filip
    Misailovic, Sasa
    Papadopoulos, Alessandro
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ray, Suprio
    Sharifloo, Amir M.
    Shevtsov, Stepan
    Ujma, Mateusz
    Vogel, Thomas
    Control Strategies for Self-Adaptive Software Systems2017Ingår i: ACM Transactions on Autonomous and Adaptive Systems, ISSN 1556-4665, E-ISSN 1556-4703, Vol. 11, nr 4, artikel-id 24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The pervasiveness and growing complexity of software systems is challenging software engineering to de- sign systems that can adapt their behavior to withstand unpredictable, uncertain, and continuously chang- ing execution environments. Control theoretical adaptation mechanisms received a growing interest from the software engineering community in the last years for their mathematical grounding allowing formal guarantees on the behavior of the controlled systems. However, most of these mechanisms are tailored to specific applications and can hardly be generalized into broadly applicable software design and development processes. This paper discusses a reference control design process, from goal identification to the verification and validation of the controlled system. A taxonomy of the main control strategies is introduced, analyzing their applicability to software adaptation for both functional and non-functional goals. A brief extract on how to deal with uncertainty complements the discussion. Finally, the paper highlights a set of open challenges, both for the software engineering and the control theory research communities.

  • 369.
    Filipovikj, Predrag
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Automated Approaches for Formal Verification of Embedded Systems Artifacts2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Modern embedded software is so large and complex that creating the necessary artifacts, including system requirements specifications and design-time models, as well as assuring their correctness have become difficult to manage. One challenge stems from the high number and intricacy of system requirements that combine functional and possibly timing or other types of constraints, which make them hard to analyze. Another challenge is the quality assurance of various design-time models developed using Simulink as the de facto standard model-based development tool in the automotive domain, avionics domain, etc. Currently, the industrial state-of-practice resorts to simulation of Simulink models, which gives insight in the system’s behavior yet does not provide a high degree of assurance that the model behaves correctly. A potential way to address the aforementioned challenges is to apply computer-aided, mathematically-rigorous methods for specification, analysis and verification already at the requirements specification stage, but also at later development stages.

    In this thesis, we propose a set of approaches for the formal specification, analysis and verification of system requirement specifications and design-time Simulink models, with particular focus on the automotive industry. Our contributions are as follows: first, we assess the expressiveness of an existing patternbased technique for the formal requirements specification on an operational system. Based on the positive findings, we deem the technique expressive enough to capture systems requirements in controlled natural language, from which formal counterparts can be automatically generated. To bring the approach closer to the practitioners we propose a tool, called PROPAS. Next, we propose an automated consistency analysis approach based on Satisfiability Modulo Theories for the system requirements specifications formally encoded as temporal logic formulas. The approach is implemented in our PROPAS tool and is suitable to analyze the lack of logical contradictions within the system specification, at early system development phases. Our next contribution addresses the formal analysis and verification of large Simulink models. First, we propose a pattern-based and execution-order-preserving approach for transforming Simulink models into networks of stochastic timed automata, which can be analyzed using the UPPAAL SMC tool that returns the probability that a property is satisfied by the model. For the automated generation of the analysis model, we propose the SIMPPAAL tool. Our second approach is based on bounded model checking and is suitable for checking invariance properties of Simulink models. Compared to the statistical model checking approach, the invariance checking is reduced to a satisfiability problem. In case of property violation, the procedure generates a counter-example execution trace, which can be used for refining the model. In the same work we show that there exist commonly-used design patterns in Simulink models, for which the verification result is complete. The approach is supported by our SYMC tool.

    For validation of the specification patterns, and the PROPAS tool we perform a case-study evaluation with practitioners, in collaboration with our industrial partner Scania. The results show that the pattern-based approach and the PROPAS tool can be practically useful in industrial settings. We apply the statistical model-checking approach and the SIMPPAAL tool on two industrial use cases, namely Brake-by-Wire and Adjustable Speed Limiter from Volvo Group Trucks Technology, which yields encouraging results. Finally, we validate the bounded invariance-checking approach and the SYMC tool on the Brake-by-Wire system, where we demonstrate both complete and incomplete verification of invariance properties.

  • 370.
    Filipovikj, Predrag
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Increasing Embedded Systems´ Quality through Automated Specification and Analysis of Requirements and Behavioral Models2017Ingår i: 43rd International Conference on Current Trends in Theory and Practice of Computer Science SOFSEM 2017, 2017Konferensbidrag (Refereegranskat)
  • 371.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Feljan, Juraj
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Crnkovic, Ivica
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ten Tips to Succeed in Global Software Engineering Education: What Do the Students Say?2013Ingår i: Software Engineering (ICSE), 2013 35th International Conference on, 2013, s. 20-24Konferensbidrag (Refereegranskat)
    Abstract [en]

    When a project had followed advices from the best practices, we can raise a question whether the success (or failure) of the project came from following (or not following) the best practices, or whether there were additional reasons that led to the positive (or negative) outcome. In this paper we analyze a case of a student project performed as a part of our Distributed Software Development course. The project followed the advices from the "Ten Tips to Succeed in Global Software Engineering Education" publication. This paper analyzes the project work with respect to the advices. Focusing on the perspective of a student participating in the project, the paper tries to answer whether following the advices is sufficient for a positive project outcome.

  • 372.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Jagerfield, Trevor
    Mälardalens högskola.
    Nyberg, Mattias
    Scania, Södertälje, Sweden.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Integrating Pattern-based Formal Requirements Specification in an Industrial Tool-chain2016Ingår i: PROCEEDINGS 2016 IEEE 40TH ANNUAL COMPUTER SOFTWARE AND APPLICATIONS CONFERENCE WORKSHOPS (COMPSAC), VOL 2, 2016, Vol. 2, s. 167-173, artikel-id 7552198Konferensbidrag (Refereegranskat)
    Abstract [en]

    The lack of formal system specifications is a major obstacle to the widespread adoption of formal verification techniques in industrial settings. Specification patterns represent a promising approach that can fill this gap by enabling non-expert practitioners to write formal specifications based on reusing solutions to commonly occurring problems. Despite the fact that the specification patterns have been proven suitable for specification of industrial systems, there is no engineer-friendly tool support adequate for industrial adoption. In this paper, we present a tool called SESAMM Specifier in which we integrate a subset of the specification patterns for formal requirements specification, called SPS, into an existing industrial tool-chain. The tool provides the necessary means for the formal specification of system requirements and the later validation of the formally expressed behavior.

  • 373.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Mahmud, Nesredin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Marinescu, Raluca
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ljungkrantz, Oscar
    Volvo Group Trucks Technology, Gothenburg, Sweden.
    Lönn, Henrik
    Volvo Group Trucks Technology, Gothenburg, Sweden.
    Analyzing Industrial Simulink Models by Statistical Model Checking2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The evolution of automotive systems has been rapid. Nowadays, electronic brains control dozens of functions in vehicles, like braking, cruising, etc. Model-based design approaches, in environments such as MATLAB Simulink, seem to help in addressing the ever-increasing need to enhance quality, and manage complexity, by supporting functional design from predefined block libraries, which can be simulated and analyzed for hidden errors, but also used for code generation. For this reason, providing assurance that Simulink models fulfill given functional and timing requirements is desirable. In this paper, we propose a pattern-based, execution-order preserving automatic transformation of Simulink atomic and composite blocks into stochastic timed automata that can then be analyzed formally with UPPAAL Statistical Model Checker (UPPPAAL SMC). Our method is supported by the tool SIMPPAAL, which we also introduce and apply on an industrial prototype called the Brake-by-Wire system. This work enables the formal analysis of industrial Simulink models, by automatically generating their semantic counterpart.

  • 374.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nyberg, Mattias
    Scania AB CV, Södertälje, Sweden.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Automated SMT-based Consistency Checking of Industrial Critical Requirements2017Ingår i: ACM SIGAPP Applied Computing Review, ISSN 1559-6915, E-ISSN 1931-0161, Vol. 17, nr 4, s. 15-28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the ever-increasing size, complexity and intricacy of system requirements specifications, it becomes difficult to ensure their correctness with respect to certain criteria such as consistency. Automated formal techniques for consistency checking of requirements, mostly by means of model checking, have been proposed in academia. Sometimes such techniques incur a high modeling cost or analysis time, or are not applicable. To address such problems, in this paper we propose an automated consistency analysis technique of requirements that are formalized based on patterns, and checked using state-of-the-art Satisfiability Modulo Theories solvers. Our method assumes several transformation steps, from textual requirements to formal logic, and next into the format suited for the SMT tool. To automate such steps, we propose a tool, called PROPAS, that does not require any user intervention during the transformation and analysis phases, thus making the consistency analysis usable by non-expert practitioners. For validation, we apply our method on a set of timed computation tree logic requirements of an industrial automotive system called the Fuel Level Display.

  • 375.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nyberg, Mattias
    Scania, Sweden.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    SMT-based Consistency Analysis of Industrial Systems Requirements2017Ingår i: 32nd ACM SIGAPP Symposium On Applied Computing SAC2017, 2017, Vol. F128005, s. 1272-1279Konferensbidrag (Refereegranskat)
    Abstract [en]

    As the complexity of industrial systems increases, it becomes dificult to ensure the correctness of system requirements specifications with respect to certain criteria such as consistency. Automated techniques for consistency checking of requirements, mostly by means of model checking, have been proposed in academia. However, such approaches can some-times be costly in terms of modeling and analysis time or not applicable for certain types of properties. In this paper, we present a complementary method that relies on pattern-based formalization of requirements and automated consistency checking using the state-of-the-art SMT tool Z3. For validation, we apply our method on a set of timed computation tree logic requirements of an industrial automotive subsystem called the Fuel Level Display. 

  • 376.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bounded Invariance Checking of Simulink Models2019Ingår i: Proceedings of the ACM Symposium on Applied Computing, 2019, Vol. Part F147772, s. 2168-2177Konferensbidrag (Refereegranskat)
    Abstract [en]

    Currently, Simulink models can be verified rigorously against design errors or statistical properties. In this paper, we show how Simulink models can be formally analyzed against invariance properties using bounded model checking reduced to satisfiability modulo theories solving. In its basic form, the technique provides means for verification of an underlying model over bounded traces rigorously, however, in general the procedure is incomplete. We identify common Simulink block types and compositions by analyzing selected industrial models, and we show that for some of them the set of non-repeating states (reachability diameter) can be visited with a finite set of paths of finite length, yielding the verification complete. We complement our approach with a tool, called SyMC that automates the following: i) calculation of the reachability diameter size for some of the designs, ii) generation of finite (bounded) paths of the underlying Simulink model and their encoding into SMT-LIB format and iii) checking invariance properties using the Z3 SMT solver. To show the applicability of our approach, we apply it on a prototype implementation of an industrial Simulink model, namely Brake by Wire from Volvo Group Trucks Technology, Sweden. 

  • 377.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Model-Checking-based vs. SMT-based Consistency Analysis of Industrial Embedded Systems Requirements: Application and Experience2018Ingår i: Electronic Communications of the EASST, ISSN 1863-2122, E-ISSN 1863-2122, Vol. 75, s. 1-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industry relies predominantly on manual peer-review techniques for assessing the correctness of system specifications. However, with the ever-increasing size, complexity and intricacy of specifications, it becomes difficult to assure their correctness with respect to certain criteria such as consistency. To address this challenge, a technique called sanity checking has been proposed. The goal of the technique is to assess the quality of the system specification in a systematic and rigorous manner with respect to a formally-defined criterion. Predominantly, the sanity checking criteria, such as for instance consistency, are encoded as reachability or liveness properties which can then be verified via model checking. Recently, a complementary approach for checking the consistency of a system's specification by reducing it to a satisfiability problem that can be analyzed using Satisfiability Modulo Theories has been proposed. In this paper, we compare the two approaches for consistency analysis, by applying them on a relevant industrial use case, using the same definition for consistency and the same set of requirements. Since the bottlenecks of analyzing large systems formally are most often the construction of the model and the time needed to return a verdict, we carry out the comparison with respect to the: i) required effort for generating the analysis model and the latter's complexity, and ii) consistency analysis time. Assuming checking only invariance properties, our results show no significant difference in analysis time between the two approaches when applied on the same system specification under the same definition of consistency. As expected, the main difference between the two comes from the required time and effort of creating the analysis models.

  • 378.
    Filipovikj, Predrag
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Seceleanu, Cristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Specifying Industrial System Requirements using Specification Patterns: A Case Study of Evaluation with Practitioners2019Ingår i: ENASE 2019 - Proceedings of the 14th International Conference on Evaluation of Novel Approaches to Software Engineering2019, 2019, s. 92-103Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the ever-increasing size and complexity of the industrial software systems there is an imperative need for an automated, systematic and exhaustive verification of various software artifacts, such as system specifications, models, code, etc. A potential remedy for this need might lie in a pool of techniques for computer-aided verification of software related artifacts, including system specifications. The Achilles' heel of these techniques, and the main hinder for their wider adoption in industrial development process are the complexity and the specialized skill-set required for the formal encoding of specifications. To alleviate this problem, Specification Patterns that are based on the observation that the system specifications are framed within reoccurring solutions have been proposed. The approach has been shown to be expressive enough for capturing requirements in the automotive domain, however, there is a lack of empirical data that can be used to judge its practical usefulness. In this paper, we involve an existing specification-patterns-based tool, and propose a small-size evaluation of the approach with practitioners, on a case study conducted in cooperation with Scania, one of the world's leading manufacturers of heavy-load vehicles. Our results show that the specification patterns that are supported by an adequate tooling have the potential for adoption in industrial practice. 

  • 379.
    Firuzan, A.
    et al.
    Islamic Azad University, Tehran, Iran.
    Modarressi, M.
    University of Tehran and IPM School of ComputerScience, Tehran, Iran.
    Daneshtalab, Masoud
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Reshadi, M.
    Islamic Azad University, Tehran, Iran.
    Reconfigurable Network-on-Chip for 3D Neural Network Accelerators2018Ingår i: 2018 12th IEEE/ACM International Symposium on Networks-on-Chip, NOCS 2018, Institute of Electrical and Electronics Engineers Inc. , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Parallel hardware accelerators for large-scale neural networks typically consist of several processing nodes, arranged as a multi- or many-core system-on-chip, connected by a network-on-chip (NoC). Recent proposals also benefit from the emerging 3D memory-on-logic architectures to provide sufficient bandwidth for neural networks. Handling the heavy traffic between neurons and memory and also the multicast-based inter-neuron traffic, which often varies over time, is the most challenging design consideration for the networks-on-chip in such accelerators. To address these issues, a reconfigurable network-on-chip architecture for 3D memory-on-logic neural network accelerators is presented in this paper. The reconfigurable NoC can adapt its topology to the on-chip traffic patterns. It can be also configured as a tree-like structure to support multicast-based neuron-to-neuron and memory-to-neuron traffic of neural networks. The evaluation results show that the proposed architecture can better manage the multicast-based traffic of neural networks than some state-of-the-art topologies and considerably increase throughput and power efficiency. 

  • 380.
    Flemström, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Tech. Report: Similarity Function Evaluation2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report presents details on and an in-depth evaluation of a similarity function used for detecting similar test steps in manual test cases, written in natural language. Using an industrial data set of 65 000 test steps, we show that even though the similarity function builds on standard functions from the open source data base Postgres, it is capable of finding similarities in parity of what the state of the art suggests. Rather few miss classifications were found. We also show that by fine tuning the function, the number of clusters of similar can be reduced by 13%. Manual inspection further shows that there is potential to reduce the set of clusters even more.

  • 381.
    Flemström, Daniel
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Afzal, Wasif
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sundmark, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Exploring Test Overlap in System Integration: An Industrial Case Study2016Ingår i: 42nd Euromicro Conference series on Software Engineering and Advanced Applications SEAA 2016, 2016, s. 303-312Konferensbidrag (Refereegranskat)
    Abstract [en]

    Tougher safety regulations, global competition and ever increasing complexity of embedded software puts extensive pressure on the effectiveness of the software testing procedures. Previous studies have found that there exist overlaps (i.e., multiple instances of highly similar test cases) and even redundancies in the software testing process. Such overlap has been found between versions, variants and integration levels, but primarily at unit test level. Given large embedded systems involving many subsystems, does overlap exist within the system integration testing as well? In this paper, we present an industrial case study, aiming to a) evaluate if there exist test overlaps within the given context, b) if so, investigate how these overlaps are distributed, and c) find ways of reducing test effort by investigating how the knowledge of overlaps and their distribution may be used for finding candidate test cases for automation, maintenance or even removal. We have studied manual test cases, written in natural language, at a large vehicular manufacturer in Sweden. In particular, we have collected and analyzed test cases from the system integration testing levels of four different projects of a vehicle control management system. Using a similarity function, we evaluate if any overlaps between test cases exist, and where. We found that overlaps do exist within the system integration level, particularly in the form of partial test step sequences. However, very few test cases overlapped in their entirety. Some candidates for test step automation and update propagation were identified, but none for easy removal.

  • 382.
    Forsberg, Håkan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Schwierz, Andreas
    Technische Hochschule Ingolstadt, Germany.
    Lundqvist, Kristina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Assurance Strategy for New Computing Platforms in Safety-Critical Avionics2019Ingår i: Aerospace Technology Congress 2019 FT2019, Stockholm, Sweden, 2019, s. 137-144Konferensbidrag (Refereegranskat)
    Abstract [en]

    An assurance strategy for new computing platforms in safety-critical avionics has to be flexible and take into account different types of commercial-of-the-shelf (COTS) hardware technologies. Completely new COTS technologies are already being introduced and successfully used in other domains. Good examples are heterogeneous platforms, hardware-based machine learning and approximate computing. Current avionics certification guidance material cannot cope with next generation of devices. We suggest using the generic assurance approach of the Overarching Properties (OPs) together with assurance cases to argument that COTS assurance objectives are met and to achieve the flexibility required for future computing platforms. We introduce a novel assurance cased-based OP approach in [1] and refine the work into a framework in [2]. Within this framework we are able to integrate COTS technology specific assurance objectives using a five-step process. In this paper, we show through some representative examples of emerging computing platforms that our strategy is a way forward for new platforms in safety-critical avionics.

  • 383.
    Fotouhi, Hossein
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Causevic, Adnan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Vahabi, Maryam
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Interoperability in heterogeneous Low-Power Wireless Networks for Health Monitoring Systems2016Ingår i: 2016 IEEE International Conference on Communications Workshops, ICC 2016, 2016, s. 393-398Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ensuring interoperability in the future Internet of Things applications can be a challenging task, especially in mission-critical applications such as Health Monitoring Systems. Existing low-power wireless network architectures are designed in isolated networks, and ensure a satisfying level of performance in homogeneous networks. However, with co-existence of different low-power networks, the interoperability related problems arise. To bridge this gap in this paper, we study various protocol stacks (i.e., Bluetooth, Bluetooth Low Energy, IEEE 802.15.4, ZigBee, 6LoWPAN and IEEE 802.15.6), and explain their specific features. Furthermore, we provide a generic protocol stack design that facilitates multiple radios with different protocol stacks, regardless of being IP-based or non-IP-based networks. We see this approach as a possibility to enhance network performance in terms of reliability, timeliness, and security, while providing higher levels of scalability and connectivity.

  • 384.
    Fotouhi, Hossein
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portuga.
    Moreira, Daniel
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal.;Truphone, Lisbon, Portugal..
    Alves, Mario
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal..
    Yomsi, Patrick Meumeu
    Politecn Porto ISEP IPP, CISTER INESC TEC, Oporto, Portugal..
    mRPL plus: A mobility management framework in RPL/6LoWPAN2017Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 104, s. 34-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The next generation Internet (also known as Internet-of-Things - IoT), will ubiquitously integrate trillions of computing devices of all kinds, shapes and sizes. For this ubiquity to materialize, a key aspect will certainly be interoperability, the capability of different technologies (e.g. different communication protocols at both horizontal and vertical levels, different hardware platforms, different operating systems, fixed and mobile nodes, etc) to talk to and understand each other. A major enabler for this interoperability is the use of standard and commercial-off-the-shelf technologies (e.g. communication protocols, hardware platforms, operating systems). As IPv6 has become the de-facto communication technology for the Internet, 6LoWPAN has recently started paving the way for extending the Internet to low-power low-cost wireless devices. However, while mobility support will be a requirement (or at least beneficial) in many applications contexts, the support of mobile nodes in the default 6loWPAN/RPL protocol leads to excessive packet loss and delays. In this work, we show that interoperability between fixed and mobile nodes can be successfully achieved through the use of appropriate hand-off and topology management techniques. We propose a mobility management framework (dubbed mRPL+) unifying two hand-off models: (1) hard hand-off, where a mobile node has to break a link before finding a new link, and (2) soft hand-off, where a mobile node selects the new link before disconnecting from the current one. Importantly, mRPL+ is integrated in the 6LoWPAN/RPL stack in a backward compatible manner. Simulation results indicate that in a network with mobile nodes, packet delivery ratio with mRPL+ is nearly 100%, where RPL achieves 80% in best case. Hand-off process has a disconnected period of few milliseconds (hand-off delay = 4 ms), while RPL experiences few seconds of disconnection during node's mobility (3 - 10 s). (C) 2017 Elsevier B.V. All rights reserved.

  • 385.
    Fotouhi, Hossein
    et al.
    Polytechnic Institute of Porto, CISTER/INESC-TEC, ISEP, Portugal .
    Moreira, Daniel
    Polytechnic Institute of Porto, CISTER/INESC-TEC, ISEP, Portugal .
    Alves, Mário
    Polytechnic Institute of Porto, CISTER/INESC-TEC, ISEP, Portugal .
    MRPL: Boosting mobility in the Internet of Things2015Ingår i: Ad hoc networks, ISSN 1570-8705, E-ISSN 1570-8713, Vol. 26, s. 17-35Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The 6loWPAN (the light version of IPv6) and RPL (routing protocol for low-power and lossy links) protocols have become de facto standards for the Internet of Things (IoT). In this paper, we show that the two native algorithms that handle changes in network topology – the Trickle and Neighbor Discovery algorithms – behave in a reactive fashion and thus are not prepared for the dynamics inherent to nodes mobility. Many emerging and upcoming IoT application scenarios are expected to impose real-time and reliable mobile data collection, which are not compatible with the long message latency, high packet loss and high overhead exhibited by the native RPL/6loWPAN protocols. To solve this problem, we integrate a proactive hand-off mechanism (dubbed smart-HOP) within RPL, which is very simple, effective and backward compatible with the standard protocol. We show that this add-on halves the packet loss and reduces the hand-off delay dramatically to one tenth of a second, upon nodes’ mobility, with a sub-percent overhead. The smart-HOP algorithm has been implemented and integrated in the Contiki 6LoWPAN/RPL stack and validated through extensive simulation and experimentation.

  • 386.
    Fotouhi, Hossein
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Vahabi, Maryam
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rabet, Iliar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Alves, Mário
    Politecnico do Porto, ISEP/IPP, Porto, Portugal.
    MobiFog: Mobility Management Framework for Fog-assisted IoT Networks2019Ingår i: IEEE Global Conference on Internet of Things GCIoT'19, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobility is becoming a challenging issue in upcoming IoT applications, where it is crucial to employ mobile entities. Patients with sensors attached to their body in health monitoring application, AGVs in industrial monitoring and factory automation applications, cars with several sensing devices in vehicular applications are a few examples of use cases with the need for mobile nodes. In parallel, Fog computing has revolutionized network architecture, while enabling local processing of measurements, and reducing bandwidth overhead, which results in a more reliable system and real-time support. However, mobility management is a missing framework within the mobile IoT networks with Fog computing architecture. This paper provides a simple and generic seamless handoff model, dubbed as MobiFog, where it addresses the handoff mechanism with zero delay, while providing high reliability.

  • 387.
    Fotouhi, Hossein
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Vahabi, Maryam
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ray, Apala
    ABB Corporate Research, India.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    SDN-TAP: An SDN-based Traffic Aware Protocol for Wireless Sensor Networks2016Ingår i: 18th International Conference on e-Health Networking, Applictions and Services Healthcom'16, 2016, artikel-id 7749527Konferensbidrag (Refereegranskat)
    Abstract [en]

    Congestion control is a challenging issue in wireless sensor networks with limited channel bandwidth. Thus, many protocols have been designed to provide a distributed traffic control during packet forwarding. However, all these approaches are applied to single-hop communication networks, ignoring the multi-hop restrictions. In this work, we take advantage of software defined networking paradigm by devising a controller node in such a way that it collects all the necessary information from wireless sensor network nodes. Thus, based on hop count and local traffic information, controller decides for possible flow path changes to evenly distribute the traffic. The evaluations revealed that the SDN-TAP outperforms conventional routing protocols by reducing packet loss rate up to 46%.

  • 388.
    Franke, Ulrik
    et al.
    RISE SICS – Swedish Institute of Computer Science, Sweden.
    Ciccozzi, Federico
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Characterization of trade-off preferences between non-functional properties2018Ingår i: Information Systems, ISSN 0306-4379, E-ISSN 1873-6076, Vol. 74, nr 2, s. 86-102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient design and evolution of complex software intensive systems rely on the ability to make informed decisions as early as possible in the life cycle. Such informed decisions should take both the intended functional and non-functional properties into account. Especially regarding the latter, it is both necessary to be able to predict properties and to prioritize them according to well-defined criteria. In this paper we focus on the latter problem, that is to say how to make trade-offs between non-functional properties of software intensive systems. We provide an approach based on the elicitation of utility functions from stake-holders and subsequent checks for consistency among these functions. The approach is exploitable through an easy-to-use GUI, which is also presented. Moreover, we describe the setup and the outcome of our two-fold validation based on exploratory elicitations with students and practitioners.

  • 389.
    Fransson, Tobias
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Simulators for formal languages, automata and theory of computation with focus on JFLAP2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report discusses simulators in automata theory and which one should be best for use in laboratory assignments. Currently, the Formal Languages, Automata and Theory of Computation course (FABER) at Mälardalen University uses the JFLAP simulator for extra exercises. To see if any other simulators would be useful either along with JFLAP or standalone, tests were made with nine programs that are able to graphically simulate automata and formal languages. This thesis work started by making an overview of simulators currently available.After the reviews it has become clear to the author that JFLAP is the best choice for majority of cases. JFLAP is also the most popular simulator in automata theory courses worldwide.To support the use of JFLAP for the course a manual and course assignments are created to help the student to getting started with JFLAP. The assignments are expected to replace the current material in the FABER course and to help the uninitiated user to get more out of JFLAP.

  • 390.
    Frasheri, Mirgita
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Curuklu, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Analysis of perceived helpfulness in adaptive autonomous agent populations2018Ingår i: Transactions on Computational Collective Intelligence XXVIII, Springer Verlag , 2018, Vol. 10780, s. 221-252Konferensbidrag (Refereegranskat)
    Abstract [en]

    Adaptive autonomy allows agents to change their autonomy levels based on circumstances, e.g. when they decide to rely upon one another for completing tasks. In this paper, two configurations of agent models for adaptive autonomy are discussed. In the former configuration, the adaptive autonomous behavior is modeled through the willingness of an agent to assist others in the population. An agent that completes a high number of tasks, with respect to a predefined threshold, increases its willingness, and vice-versa. Results show that, agents complete more tasks when they are willing to give help, however the need for such help needs to be low. Agents configured to be helpful will perform well among alike agents. The second configuration extends the first by adding the willingness to ask for help. Furthermore, the perceived helpfulness of the population and of the agent asking for help are used as input in the calculation of the willingness to give help. Simulations were run for three different scenarios. (i) A helpful agent which operates among an unhelpful population, (ii) an unhelpful agent which operates in a helpful populations, and (iii) a population split in half between helpful and unhelpful agents. Results for all scenarios show that, by using such trait of the population in the calculation of willingness and given enough interactions, helpful agents can control the degree of exploitation by unhelpful agents. © Springer International Publishing AG, part of Springer Nature 2018.

  • 391.
    Frasheri, Mirgita
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Curuklu, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Comparison Between Static and Dynamic Willingness to Interact in Adaptive Autonomous Agents2018Ingår i: Proceedings of the 10th International Conference on Agents and Artificial Intelligence, 2018, Vol. 1, s. 258-267Konferensbidrag (Refereegranskat)
    Abstract [en]

    Adaptive autonomy (AA) is a behavior that allows agents to change their autonomy levels by reasoning on their circumstances. Previous work has modeled AA through the willingness to interact, composed of willingness to ask and give assistance. The aim of this paper is to investigate, through computer simulations, the behavior of agents given the proposed computational model with respect to different initial configurations, and level of dependencies between agents. Dependency refers to the need for help that one agent has. Such need can be fulfilled by deciding to depend on other agents. Results show that, firstly, agents whose willingness to interact changes during run-time perform better compared to those with static willingness parameters, i.e. willingness with fixed values. Secondly, two strategies for updating the willingness are compared, (i) the same fixed value is updated on each interaction, (ii) update is done on the previous calculated value. The maximum number of completed tasks which need assistance is achieved for (i), given specific initial configurations.

  • 392.
    Frasheri, Mirgita
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Cürüklü, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Towards Collaborative Adaptive Autonomous Agents2017Ingår i: ICAART: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON AGENTS AND ARTIFICIAL INTELLIGENCE, VOL 1, 2017, s. 78-87Konferensbidrag (Refereegranskat)
    Abstract [en]

    Adaptive autonomy enables agents operating in an environment to change, or adapt, their autonomy levels by relying on tasks executed by others. Moreover, tasks could be delegated between agents, and as a result decision-making concerning them could also be delegated. In this work, adaptive autonomy is modeled through the willingness of agents to cooperate in order to complete abstract tasks, the latter with varying levels of dependencies between them. Furthermore, it is sustained that adaptive autonomy should be considered at an agent's architectural level. Thus the aim of this paper is two-fold. Firstly, the initial concept of an agent architecture is proposed and discussed from an agent interaction perspective. Secondly, the relations between static values of willingness to help, dependencies between tasks and overall usefulness of the agents' population are analysed. The results show that a unselfish population will complete more tasks than a selfish one for low dependency degrees. However, as the latter increases more tasks are dropped, and consequently the utility of the population degrades. Utility is measured by the number of tasks that the population completes during run-time. Finally, it is shown that agents are able to finish more tasks by dynamically changing their willingness to cooperate.

  • 393.
    Frasheri, Mirgita
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Trinh, LanAnh
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Curuklu, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Failure Analysis for Adaptive Autonomous Agents using Petri Nets2017Ingår i: Proceedings of the 2017 Federated Conference on Computer Science and Information Systems, FedCSIS 2017, 2017, s. 293-297Konferensbidrag (Refereegranskat)
    Abstract [en]

    Adaptive autonomous (AA) agents are able to make their own decisions on when and with whom to share their autonomy based on their states. Whereas dependability gives evidence on whether a system, (e.g. an agent team), and its provided services are to be trusted. In this paper, an initial analysis on AA agents with respect to dependability is conducted. Firstly, AA is modeled through a pairwise relationship called willingness of agents to interact, i.e. to ask for and give assistance. Secondly, dependability is evaluated by considering solely the reliability attribute, which presents the continuity of correct services. The failure analysis is realized by modeling the agents through Petri Nets. Simulation results indicate that agents drop slightly more tasks when they are more willing to interact than otherwise, especially when the fail-rate of individual agents increases. Conclusively, the willingness should be tweaked such that there is compromise between performance and helpfulness.

  • 394.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Land, Rikard
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Packaging Component-Analysis for Reuse2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    Component-Based Software Engineering (CBSE) promises an improved ability to reuse software which would potentially decrease the development time while also improving the quality of the system, since the components are (re-)used by many. However, CBSE has not been as successful in the embedded systems domain as in the desktop domain, partly because requirements on embedded systems are stricter (e.g. requirements on safety, real-time and minimizing hardware resources). Moreover these requirements differ between industrial domains. Paradoxically, components should be context-unaware to be reusable at the same time as they should be context sensitive in order to be predictable and resource efficient. This seems to be a fundamental problem to overcome before the CBSE paradigm will be successful also in the embedded systems domain. Another problem is that some of the stricter requirements for embedded systems require certain analyses to be made, which may be very complicated and time-consuming for the system developer.

    This paper describes how one particular kind of analysis, of worst-case execution time, would fit into the CBSE development processes so that the component developer performs some analyses and presents the results in a form that is easily used for component and system verification during system development. This process model is not restricted to worst-case execution time analysis, but we believe other types of analyses could be performed in a similar way.

  • 395.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik. CC Systems, Västerås, Sweden.
    Land, Rikard
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Reusable Component Analysis for Component-Based Embedded Real-Time Systems2007Ingår i: Proceedings of the International Conference on Information Technology Interfaces, ITI, 2007, 2007, s. 615-620Konferensbidrag (Refereegranskat)
    Abstract [en]

    Component-Based Software Engineering (CBSE) promises an improved ability to reuse software which would potentially decrease the development time while also improving the quality of the system, since the components are (re-)used by many. However, CBSE has not been as successful in the embedded systems domain as in the desktop domain, partly because requirements on embedded systems are stricter (e.g. requirements on safety, real-time and minimizing hardware resources). Moreover these requirements differ between industrial domains. Paradoxically, components should be context-unaware to be reusable at the same time as they should be context sensitive in order to be predictable and resource efficient. This seems to be a fundamental problem to overcome before the CBSE paradigm will be successful also in the embedded systems domain. Another problem is that some of the stricter requirements for embedded systems require certain analyses to be made, which may be very complicated and time-consuming for the system developer.

    This paper describes how one particular kind of analysis, of worst-case execution time, would fit into the CBSE development processes so that the component developer performs some analyses and presents the results in a form that is easily used for component and system verification during system development. This process model is not restricted to worst-case execution time analysis, but we believe other types of analyses could be performed in a similar way.

  • 396.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Ermedahl, Andreas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Nolin, Mikael
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Clustering Worst-Case Execution Times for Software Components2007Ingår i: Proceedings of the 7th International Workshop on Worst Case Execution Time Analysis (WCET'07), Pisa, Italy, 2007, s. 19-25Konferensbidrag (Refereegranskat)
    Abstract [en]

    For component-based systems, classical techniques for WCET-estimation produce unacceptable overestimations of the WCET. This is because software components have more general behavior in order to support reuse. Existing tools and methods for component-based software engineering (CBSE) do not yet adequately consider reusable analyses.

    We present a method that allows different WCETs to be associated with subsets of the component behavior by clustering WCETs with respect to behavior. The method is intended to be used for facilitating reusable WCET analysis for reusable software components. We illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for components with rich behavior.

  • 397.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Ermedahl, Andreas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Sjödin, Mikael
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Contract-Based Reusable Analysis for Software Components with Extra-Functional Properties2007Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS'07), Pisa, Italy, 2007, s. 57-60Konferensbidrag (Refereegranskat)
    Abstract [en]

    Component-based software engineering (CBSE) for embedded systems is currently gaining ground because of shortened time-to-market, reduced development costs and increased software quality. One main characteristic of CBSE that enable these benefits is its facilitation of component reuse. However, existing tools and methods do not consider reuse of extra-functional properties in these systems.

    In this paper we extend our previous work on contract-based reusable execution time predictions for software components with additional extra-functional properties, such as memory and energy consumption.

  • 398.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Ermedahl, Andreas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Sjödin, Mikael
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Worst-Case Execution Time Clustering for Software Components2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    For component-based systems, classical techniques for WCET-estimation produce unacceptable overestimations of the WCET. This is because software components have more general behavior in order to support reuse. Existing tools and methods for component-based software engineering (CBSE) do not yet adequately consider reusable analyses. We present a method that allows different WCETs to be associated with subsets of the component behavior by clustering WCETs with respect to behavior. The method is intended to be used for facilitating reusable WCET analysis for reusable software components. We illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for components with rich behavior.

  • 399.
    Fredriksson, Johan
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Nolte, Thomas
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Sjödin, Mikael
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Schmidt, Heinz
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Reusing Worst-Case Execution Time Analysis with Component Contracts2007Ingår i: Proceedings of the 9th Real-Time in Sweden (RTiS'07), 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a contract-based technique to achieve reuse of known worst-case execution times (WCET) in conjunction with reuse of software components. For resource constrained systems, or systems where high degree of predictability is needed, classical techniques for WCET-estimation will result in unacceptable overestimation of the execution-time of reusable software components with rich behavior. Our technique allows different WCETs to be associated with subsets of the component behavior. The appropriate WCET for any usage context of the component is selected be means of component contracts over the input domain. In a case-study we illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for reusable components with rich behavior.

  • 400.
    Funk, Peter
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Second Generation Intelligen Sensor Systems2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is an increased market demand of "smart" sensor systems, both from system and product developers as well as end users. The first generation intelligent sensor systems are sensors with some limited processing capacity that may be used for processing or compressing data, or sending data, calculating average etc. Our proposed definition of the second generation intelligent sensors are that they are capable of behaviour, that a human would classify as intelligent if seen in s sensor. This functionality may be integrated into the hardware, or in the sensors control program. <br><br>

    Example of such functionality may be to identify if the sensor is fully functional and self-calibrating properties. The sensor may also send confidence estimation on how confident it is in the current sensor readings. The sensor may also learn to recognise different internal and external disturbances, e.g. learn how the signal of a close mobile phone influences the sensor readings and correct the readings. Some sensors may also have delegated responsibilities, e.g. turn some sensitive equipment of if they detect some serious conditions needing immediate action, and where a human or centralized response would not be able to arrive in time. This could be to lower the clock speed to avoid overheating. <br><br>

    If sensors are equipped with communication capabilities then an intelligent sensor could be classified as an agent. Wooldridge and Jennings (1995) defines agents to be computer systems (hardware and software, able to observe its environment and influence its environment) that have properties such as: <br>

    • autonomy<br>

    • social abilities<br>

    • reactivity and pro-activeness<br>

    This does not necessarily mean that they have to be designed and implemented with different methods than today. Methods and techniques from artificial intelligent (AI), such as agents or learning systems are today implemented with main steam methods and techniques. The difference is what the requirements are and it is a different way of thinking, often opening a door to new solutions, not always thought of when taking an incremental approach to improvement and extended functionality. <br>

    Suggested important properties in an agent based approach to sensors are: <br>

    1. flexibility and decentralised decision making. <br>

    2. localized learning and experience reuse. <br>

    3. learning and experience sharing between agents with similar tasks. <br>

    4. ability to collaborate with other agents or even humans<br>

    This functionality could be implemented both in hardware or software. An interesting question is how a sensor handles feedback, both positive and negative. Other interesting opportunities arise when sensors communicate, e.g. sensors may have limited knowledge on their functionality and relation. This enables an intelligent sensor to verify its own functionality by comparing its own readings with other sensor readings. Also learning optimal intervals for cleaning or recalibrations may be such an option. If these sensors are part of a complex centrally controlled process, the process may preserve some basic behaviour if the central control process is experiencing some dysfunctions. <br><br>

    Methods and techniques from artificial intelligence area already widely used in many areas but also offer interesting and potential valuable benefits also to areas not traditionally thought of when speaking of AI, e.g. microsystems.

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