https://www.mdu.se/

mdu.sePublications
Change search
Refine search result
1234567 101 - 150 of 1454
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Du, Yong
    Almeida, L.
    University of Porto, Porto, Portugal .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dynamic reconfiguration in HaRTES switched ethernet networks2016In: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, 2016, article id Article number 7496510Conference paper (Refereed)
    Abstract [en]

    The ability of reconfiguring a system during runtime is essential for dynamic real-time applications in which resource usage is traded online for quality of service. The HaRTES switch, which is a modified Ethernet switch, holds this ability for the network resource, and at the same time it provides hard real-time support for both periodic and sporadic traffic. Although the HaRTES switch technologically caters this ability, a protocol to actually perform the dynamic reconfiguration is missing in multi-hop HaRTES networks. In this paper we introduce such a protocol that is compatible with the traffic scheduling method used in the architecture. We prove the correctness of the protocol using a model checking technique. Moreover, we conduct a set of simulation experiments to show the performance of the protocol and we also show that the reconfiguration process is terminated within a bounded time. 

  • 102.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Khalilzad, Nima
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IS (Embedded Systems).
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sander, Ingo
    Royal Institute of Technology, Sweden.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Designing End-to-end Resource Reservations in Predictable Distributed Embedded Systems2017In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 53, no 6, p. 916-956Article in journal (Refereed)
    Abstract [en]

    Contemporary distributed embedded systems in many domains have become highly complex due to ever-increasing demand on advanced computer controlled functionality. The resource reservation techniques can be effective in lowering the software complexity, ensuring predictability and allowing flexibility during the development and execution of these systems. This paper proposes a novel end-to-end resource reservation model for distributed embedded systems. In order to support the development of predictable systems using the proposed model, the paper provides a method to design resource reservations and an end-to-end timing analysis. The reservation design can be subjected to different optimization criteria with respect to runtime footprint, overhead or performance. The paper also presents and evaluates a case study to show the usability of the proposed model, reservation design method and end-to-end timing analysis. 

  • 103.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    End-to-end Resource Reservations in Distributed Embedded Systems2016In: Proceedings - 2016 IEEE 22nd International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2016, 2016, p. 1-11, article id 7579921Conference paper (Refereed)
    Abstract [en]

    The resource reservation techniques provide effective means to lower the software complexity, ensure predictability and allow flexibility during the development and execution of complex distributed embedded systems. In this paper we propose a new end-to-end resource reservation model for distributed embedded systems. The model is comprehensive in such a way that it supports end-to-end resource reservations on distributed transactions with various activation patterns that are commonly used in industrial control systems. The model allows resource reservations on processors and real-time network protocols. We also present timing analysis for the distributed embedded systems that are developed using the proposed model. The timing analysis computes the end-to-end response times as well as delays such as data age and reaction delays. The presented analysis also supports real-time networks that can autonomously initiate transmissions. Such networks are not supported by the existing analyses. We also include a case study to show the usability of the model and end-to-end timing analysis with resource reservations.

  • 104.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Daneshtalab, Masoud
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Casamayor, Victor
    Technical University of Vienna, Austria.
    Nelissen, Geoffrey
    Eindhoven University of Technology, Netherlands.
    Towards a Predictable and Cognitive Edge-Cloud Architecture for Industrial Systems2022In: Proceedings of RAGE 2022, 2022Conference paper (Refereed)
  • 105.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Patti, Gaetano
    University of Catania, Italy.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Alderisi, Giuliana
    University of Catania, Italy.
    Lo Bello, Lucia
    University of Catania, Italy.
    Schedulability Analysis of Ethernet Audio Video Bridging Networks with Scheduled Traffic Support2017In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 53, no 4, p. 526-577Article in journal (Refereed)
    Abstract [en]

    The IEEE Audio Video Bridging (AVB) technology is nowadays under consideration in several automation domains, such as, automotive, avionics, and industrial communications. AVB offers several benefits, such as open specifications, the existence of multiple providers of electronic components, and the real-time support, as AVB provides bounded latency to real-time traffic classes. In addition to the above mentioned properties, in the automotive domain, comparing with the existing in-vehicle networks, AVB offers significant advantages in terms of high bandwidth, significant reduction of cabling costs, thickness and weight, while meeting the challenging EMC/EMI requirements. Recently, an improvement of the AVB protocol, called the AVB ST, was proposed in the literature, which allows for supporting scheduled traffic, i.e., a class of time-sensitive traffic that requires time-driven transmission and low latency. In this paper, we present a schedulability analysis for the real-time traffic crossing through the AVB ST network. In addition, we formally prove that, if the bandwidth in the network is allocated according to the AVB standard, the schedulability test based on response time analysis will fail for most cases even if, in reality, these cases are schedulable. In order to provide guarantees based on analysis test a bandwidth over-reservation is required. In this paper, we propose a solution to obtain a minimized bandwidth over-reservation. To the best of our knowledge, this is the first attempt to formally spot the limitation and to propose a solution for overcoming it. The proposed analysis is applied to both the AVB standard and the AVB ST. The analysis results are compared with the results of several simulative assessments, obtained using OMNeT++, on both automotive and industrial case studies. The comparison between the results of the analysis and the simulation ones shows the effectiveness of the analysis proposed in this work.

  • 106.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Becker, Matthias
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Cloud Computing in Factory Automation: A Survey and Open Problems2020Report (Other academic)
  • 107.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bucaioni, Alessio
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Conceptual Framework for Software Modeling of Automation Systems2022In: ITNG 2022 19th International Conference on Information Technology-New Generations. Advances in Intelligent Systems and Computing, vol 1421, 2022, Vol. 1421Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose a conceptual framework to facilitate the design and development of an automation system in which time-sensitive networking (TSN) is utilized for the backbone network and OPC UA is used for modeling of data exchange over TSN. As the configuration of OPC UA over TSN in a large automation setup can be a challenging task and requires specific expertise, we propose to add an abstract modeling layer that adopts the concepts of model-based development and component-based software engineering to facilitate the development of these systems. The proposed conceptual model can be automatically translated to the OPC UA modeling format. Such a modeling view will significantly reduce the complexity of OPC UA configurations, specially in large automation systems. Another benefit of the proposed framework is that the engineers, who do not have high levels of expertise in OPC UA, will be able to easily configure the OPC UA nodes in the automation system that utilize TSN for backbone communication.

  • 108.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Clegg, Kester
    Univ York, York, N Yorkshire, England..
    Corneo, Lorenzo
    Uppsala Univ, Uppsala, Sweden..
    Hawkins, Richard
    Univ York, York, N Yorkshire, England..
    Jaradat, Omar
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Gulisano, Vincenzo Massimiliano
    Chalmers Univ, Gothenburg, Sweden..
    Nikolakopoulos, Yiannis
    Chalmers Univ, Gothenburg, Sweden..
    Service Level Agreements for Safe and Configurable Production Environments2018In: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), IEEE , 2018, p. 1252-1255Conference paper (Refereed)
    Abstract [en]

    This paper focuses on Service Level Agreements (SLAs) for industrial applications that aim to port some of the control functionalities to the cloud. In such applications, industrial requirements should be reflected in SLAs. In this paper, we present an approach to integrate safety-related aspects of an industrial application to SLAs. We also present the approach in a use case. This is an initial attempt to enrich SLAs for industrial settings to consider safety aspects, which has not been investigated thoroughly before.

  • 109.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Girs, Svetlana
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dynamic Resource Distribution using SDN in Wireless Networks2020In: 21st IEEE International Conference on Industrial Technology ICIT'20, 2020, p. 967-972Conference paper (Refereed)
  • 110.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Khalilzad, Nima
    Qamcom Research and Technology, Stockholm, Sweden.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Modeling, Designing and Analyzing Resource Reservations in Distributed Embedded Systems2018In: Real-Time Modelling and Processing for Communication Systems / [ed] Springer, Springer , 2018, p. 203-256Chapter in book (Other academic)
  • 111.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lundbäck, John
    Arcticus Systems AB, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Sweden.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Sweden.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Modeling and Timing Analysis of Vehicle Functions Distributed over Switched Ethernet2017In: IECON 2017 - 43RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, 2017, p. 8419-8424Conference paper (Refereed)
    Abstract [en]

    This paper proposes an approach to model switched Ethernet communication within a model- and component-based software development framework for vehicular distributed embedded systems. The paper also presents a method to extract the network timing model from the systems that use switched Ethernet networks. In order to provide a proof of concept, an existing industrial component model and its tool suite, namely RCM and Rubus-ICE respectively, are extended by implementing the modeling technique, the timing model extraction method and response-time analysis of the Ethernet AVB protocol. The extensions to RCM are backward compatible with the modeling and end-to-end timing analysis of traditional in-vehicle networks and legacy (previously developed) vehicular distributed embedded systems. Furthermore, the paper discusses the implementation and test strategy used in this work. Finally, the usability of the modeling approach and implemented timing analysis is demonstrated by modeling and time analyzing a vehicular application case study with the extended component model and tool suite.

  • 112.
    Aslam, Mudassar
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bringing Visibility in the Clouds: using Security, Transparency and Assurance Services2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The evolution of cloud computing allows the provisioning of IT resources over the Internet and promises many benefits for both - the service users and providers. Despite various benefits offered by cloud based services, many users hesitate in moving their IT systems to the cloud mainly due to many new security problems introduced by cloud environments. In fact, the characteristics of cloud computing become basis of new problems, for example, support of third party hosting introduces loss of user control on the hardware; similarly, on-demand availability requires reliance on complex and possibly insecure API interfaces; seamless scalability relies on the use of sub-providers; global access over public Internet exposes to broader attack surface; and use of shared resources for better resource utilization introduces isolation problems in a multi-tenant environment. These new security issues in addition to existing security challenges (that exist in today's classic IT environments) become major reasons for the lack of user trust in cloud based services categorized in Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) or Infrastructure-as-a-Service (IaaS).

    The focus of this thesis is on IaaS model which allows users to lease IT resources (e.g. computing power, memory, storage, etc.) from a public cloud to create Virtual Machine (VM) instances. The public cloud deployment model considered in this thesis exhibits most elasticity (i.e. degree of freedom to lease/release IT resources according to user demand) but is least secure as compared to private or hybrid models. As a result, public clouds are not trusted for many use cases which involve processing of security critical data such as health records, financial data, government data, etc. However, public IaaS clouds can also be made trustworthy and viable for these use cases by providing better transparency and security assurance services for the user. In this thesis, we consider such assurance services and identify security aspects which are important for making public clouds trustworthy. Based upon our findings, we propose solutions which promise to improve cloud transparency thereby realizing trustworthy clouds.

    The solutions presented in this thesis mainly deal with the secure life cycle management of the user VM which include protocols and their implementation for secure VM launch and migration. The VM launch and migration solutions ensure that the user VM is always hosted on correct cloud platforms which are setup according to a profile that fulfills the use case relevant security requirements. This is done by using an automated platform security audit and certification mechanism which uses trusted computing and security automation techniques in an integrated solution. In addition to provide the assurance about the cloud platforms, we also propose a solution which provides assurance about the placement of user data in correct and approved geographical locations which is critical from many legal aspects and usually an important requirement of the user. Finally, the assurance solutions provided in this thesis increase cloud transparency which is important for user trust and to realize trustworthy clouds.

    Download full text (pdf)
    fulltext
  • 113.
    Asplund, Lars
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Lundqvist, Kristina
    Mälardalen University, School of Innovation, Design and Engineering.
    Safety Critical Systems Based on Formal Models2000In: ACM SIGAda Letters, ISSN 1094-3641, Vol. XX, no 4, p. 32-39Article in journal (Refereed)
    Abstract [en]

    The Ravenscar profile for high integrity systems using Ada 95 is well defined in all real-time aspects. The complexity of the run-time system has been reduced to allow full utilization of formal methods for applications using the Ravenscar profile. In the Mana project a tool set is being developed including a formal model of a Ravenscar compliant run-time system, a gnat compatible run-time system, and an ASIS based tool to allow for the verification of a system including both COTS and code that is reused.

  • 114.
    Asplund, Lars
    et al.
    Uppsala University, Sweden.
    Lundqvist, Kristina
    Massachusetts Institute of Technology, USA.
    Safety Critical Systems Based on Formal Models2000In: ACM SIGAda Ada Letters - special issue on presentations from SIGAda 2000, Vol. XX, Iss. 4, 2000Conference paper (Other academic)
  • 115.
    Asplund, Lars
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Lundqvist, Kristina
    MIT, Cambridge, MA, United States .
    The Gurkh Project: A Framework for Verification and Execution of Mission Critical Applications2003In: AIAA/IEEE Digital Avionics Systems Conference - Proceedings, vol. 2, 2003, p. 10.B.1/1-10.B.1/9Conference paper (Other academic)
    Abstract [en]

    The paper contributes with three methods that together will make a complete tool-set for verification of mission critical applications. The first method is the transformation of existing Ada or VHDL code into an intermediate form. This form is used for verification by numerous different model checkers. The second method is a predictable runtime kernel that has both a verifiable formal model and is implemented in hardware to achieve full predictability. Finally, a method for transforming the intermediate form of the complete system into a hardware unit, the SafetyChip that performs runtime control of the system. This SafetyChip can catch 'out-of-state' behaviors.

  • 116.
    Assenza, Giacomo
    et al.
    University Campus Biomedico of Rome, Italy.
    Cozzani, Valerio
    University of Bologna, Italy.
    Flammini, Francesco
    Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM).
    Gotcheva, Nadezhda
    VTT Technical Research Centre of Finland, Finland.
    Gustafsson, Tommy
    Swedish Defence Research Agency, Sweden.
    Hansson, Anders
    Sectra Communications AB, Sweden.
    Heikkila, Jouko
    VTT Technical Research Centre of Finland, Finland.
    Iaiani, Matteo
    University of Bologna, Italy.
    Katsikas, Sokratis
    Norwegian University of Science and Technology, Norway.
    Nissilä, Minna
    VTT Technical Research Centre of Finland, Finland.
    Oliva, Gabriele
    University Campus Biomedico of Rome, Italy.
    Richter, Eleni
    EnBW Energie Baden-Württemberg AG, Germany.
    Roelofs, Maaike
    TNO, Netherlands Organisation for Applied Scientific Research, Netherlands.
    Saman Azari, Mehdi
    Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM).
    Setola, Roberto
    University Campus Biomedico of Rome, Italy.
    Stejin, Wouter
    TNO, Netherlands Organisation for Applied Scientific Research, Netherlands.
    Tugnoli, Alessandro
    University of Bologna, Italy.
    Vanderbeek, Dolf
    TNO, Netherlands Organisation for Applied Scientific Research, Netherlands.
    Westerdahl, Lars
    Swedish Defence Research Agency, Sweden.
    Ylönen, Marja
    VTT Technical Research Centre of Finland, Finland.
    Young, Heather
    TNO, Netherlands Organisation for Applied Scientific Research, Netherlands.
    White Paper on Industry Experiences in Critical Information Infrastructure Security: A Special Session at CRITIS 20192020In: Critical Information Infrastructures Security14th International Conference, CRITIS 2019,: Linköping, Sweden, September 23–25, 2019, Revised Selected Papers / [ed] Nadjm-Tehrani, Simin, Springer , 2020, p. 197-207Chapter in book (Refereed)
    Abstract [en]

    The security of critical infrastructures is of paramount importance nowadays due to the growing complexity of components and applications. This paper collects the contributions to the industry dissemination session within the 14th International Conference on Critical Information Infrastructures Security (CRITIS 2019). As such, it provides an overview of recent practical experience reports in the field of critical infrastructure protection (CIP), involving major industry players. The set of cases reported in this paper includes the usage of serious gaming for training infrastructure operators, integrated safety and security management in the chemical/process industry, risks related to the cyber-economy for energy suppliers, smart troubleshooting in the Internet of Things (IoT), as well as intrusion detection in power distribution Supervisory Control And Data Acquisition (SCADA). The session has been organized to stimulate an open scientific discussion about industry challenges, open issues and future opportunities in CIP research.

  • 117. Avdagic, Zikrija
    et al.
    Boskovic, Dusanka
    Causevic, Aida
    Mälardalen University, School of Innovation, Design and Engineering.
    Code Evaluation Using Fuzzy Logic2008Conference paper (Refereed)
    Abstract [en]

    This paper presents application of a fuzzy logic based system to automatically evaluate the

    maintainability of code. Code evaluation is accomplished by rating its quality provided with bad smells in

    code as inputs. Straightforward bad smells with existing software metrics tools are selected as inputs:

    duplicated code, long methods, large classes having a high cyclomatic complexity, or a large number of

    parameters and temporary fields. Removing these bad smells can result in significant code improvements

    concerning readability and maintainability. However, the precise definition of attributes like small, long, large

    or high is not clear, and their identification is rather subjective. Fuzzy logic values are suitable for capturing

    partial correspondence to attributes and fuzzy rules model have been used to describe the relation between bad

    smells and code quality. Model supporting the experimental evaluation of the fuzzy based code evaluation is

    implemented in Java.

    Key-Words: - Fuzzy Logic, Reasoning Systems, Refactoring, Bad Smells

  • 118.
    Avritzer, A
    et al.
    Siemens Corporate Research, USA.
    Weyuker, Elaine
    AT and T Labs - Research, USA.
    The Automated Generation of Test Cases using an Extended Domain Based Reliability Model2009In: Proceedings of the 2009 ICSE Workshop on Automation of Software Test, AST 2009, 2009, p. 44-52, article id 5069040Conference paper (Refereed)
  • 119.
    Awada, Imad Alex
    et al.
    University Politehnica of Bucharest, Romania.
    Cramariuc, Oana
    IT Cenetr for Science and Technology, Romania.
    Mocanu, Irina
    University Politehnica of Bucharest.
    Seceleanu, Cristina
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Kunnappilly, Ashalatha
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Florea, Adina Magda
    University Politehnica of Bucharest, Romania.
    An end- user perspective on the CAMI Ambient and Assisted Living Project2018In: INTED2018 Proceedings, 2018, p. 6776-6785Conference paper (Refereed)
    Abstract [en]

    In this paper, we present the outcomes and conclusions obtained by involving seniors from three countries (Denmark, Poland and Romania) in an innovative project funded under the European Ambient Assisted Living (ALL) program. CAMI stands for "Companion with Autonomously Mobile Interface" in "Artificially intelligent ecosystem for self-management and sustainable quality of life in AAL". The CAMI solution enables flexible, scalable and individualised services that support elderly to self-manage their daily life and prolong their involvement in the society (sharing knowledge, continue working, etc). This also allows their informal caregivers (family and friends) to continue working and participating in society while caring for their loved ones. The solution is designed as an innovative architecture that allows for individualized, intelligent self-management which can be tailored to an individual's preferences and needs. A user-centred approach has ranked health monitoring, computer supervised physical exercises and voice based interaction among the top favoured CAMI functionalities. Respondents from three countries (Poland, Romania and Denmark) participated in a multinational survey and a conjoint analysis study.

  • 120.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A refined terminology on system-of-systems substructure and constituent system states2019In: 2019 14th Annual Conference System of Systems Engineering, SoSE 2019, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 31-36Conference paper (Refereed)
    Abstract [en]

    In the field of systems-of-systems (SoS) engineering, there is broad agreement on a few characterizations, and these are currently being standardized. However, many aspects in the field still lack an established terminology. In particular, there are unclarities related to the internal structure of an SoS, and on the internal states of constituent systems. In this paper, a refined terminology is therefore proposed, which covers the internal substructure of an SoS; the states of constituent systems in relation to those substructures; and how it relates to hierarchical levels. This terminology can also be used to classify the characteristics of an SoS through different metrics. The terminology is illustrated through three examples of SoS applications in various domains. 

  • 121.
    Axelsson, Jakob
    Software and Systems Engineering Laboratory, Swedish Institute of Computer Science (SICS), Kista, Sweden .
    A Systematic Mapping of the Research Literature on System-of-Systems Engineering2015In: 10th Annual Systems of Systems Engineering Conference SOSE, 2015, p. 18-23Conference paper (Refereed)
    Abstract [en]

    The research area systems-of-systems engineering has increased rapidly over the last decade and now contains a substantial body of literature. To get an overview of the field, a systematic mapping of the literature has been done, covering over 3000 papers. It revealed a field massively dominated by US researchers, with an emphasis on military and space systems. A large number of people are involved, but few researchers focus on the area, and citations are fairly low compared to other fields. Important research topics include architecture, modeling and simulation, integration and interoperability, communication, sustainability, and safety and security. There are signs of immaturity within the research area, and it is recommended that existing venues are complemented with an international scientific event with very high standards for submissions.

  • 122.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. RISE Research Institutes of Sweden, Kista, Sweden.
    An initial analysis of operational emergent properties in a platooning system-of-systems2018In: 12th Annual IEEE International Systems Conference, SysCon 2018 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 1-8Conference paper (Refereed)
    Abstract [en]

    As systems-of-systems start to be more common in commercial applications, an analysis of emergent properties related to utility and cost for all stakeholders becomes critical. This paper describes an approach for this based on network simulation and game theory, which is applied to truck highway platooning. The emergent properties of energy efficiency and transport efficiency are studied as a consequence of the strategies for platoon formation, and it is shown that having information about the route planning of other vehicles has a significant positive effect on the properties. This indicates the need for a mediator in the platooning system-of-systems architecture. Its role is to communicate plans of the constituent systems.

  • 123.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Architectural Allocation Alternatives and Associated Concerns in Cyber-Physical Systems: A Case Study2015In: ECSAW '15 Proceedings of the 2015 European Conference on Software Architecture Workshops, 2015, Vol. Article No.15Conference paper (Refereed)
    Abstract [en]

    Cyber-physical systems is an extension of traditional embedded systems, where communication to the outside world is given more emphasis. This leads to a new design space also for software development, allowing new allocation strategies for functionality. In traditional embedded systems, all functionality was inside the product, but now it becomes possible to partition the software between the embedded systems and IT systems outside the product. This paper investigates, through a case study from the automotive domain, possible new allocation alternatives where computation is offloaded from the embedded system to a server, and what additional architectural concerns this leads to, including performance, resource utilization, robustness, and lifecycle aspects. In addition, the paper addresses new opportunities created by allocating functionality outside the embedded systems, and thus making data available for extended services, as well as the larger concerns that result on the organizational level, including new competency in architecture and DevOps.

  • 124.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Business models and roles for mediating services in a truck platooning system-of-systems2019In: 2019 14th Annual Conference System of Systems Engineering, SoSE 2019, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 113-118Conference paper (Refereed)
    Abstract [en]

    Platooning of trucks on motorways has been proposed as a method of reducing fuel consumption. It requires communication between the trucks to control the distance between them. However, this system-of-systems (SoS) cannot only contain the trucks, but also needs to include mediating off-board services for match-making to find suitable constellations of trucks, and for creating platooning incentives by distributing the profit made equally among the constituent systems. This paper analyzes what actors in the SoS would be suitable to operate these services, and also business models that cover the cost for their implementation and operation. It concludes that the truck OEMs have a vital role in creating the mediating services, and that a suitable business model would be based on usage fees for the services rather than upfront payment for platooning equipment. 

  • 125.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Experiences of Using Linked Data and Ontologies for Operational Data Sharing in Systems-of-Systems2019In: 13th Annual IEEE International Systems Conference SysCon2019, Orlando, Florida, United States, 2019Conference paper (Refereed)
    Abstract [en]

    This paper addresses the problem of exchanging complex data between the constituent systems in a system-of-systems. This is necessary to ensure that they have compatible understandings of the world surrounding them and entails a need for semantic interoperability between the constituents. Through a case study of a road construction system-of-systems, the world wide web technologies of linked data and ontologies are explored as a framework for data representation and exchange. This data includes several broad categories, such as assets, interfaces, organizations, capabilities, missions, and observations, as well as various properties of those. It is also discussed how the constituents can use this data for reasoning and decision making. The results have been validated through a simulation-based research prototype of the road construction case, from which experiences are reported.

  • 126.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. RISE Research Institutes of Sweden, Sweden.
    Game Theory Applications in Systems-of-Systems Engineering: A Literature Review and Synthesis2019In: Procedia Computer Science, E-ISSN 1877-0509, Vol. 153, p. 154-165Article in journal (Refereed)
    Abstract [en]

    Systems-of-systems (SoS) are becoming increasingly common in more and more domains, spreading from the initial focus on government-controlled areas such as defense to open market industries. This implies that collaborative SoS are becoming more important, where the constituents need to be given incentives to join and remain within the SoS. Game theory has been proposed as a framework to model and analyze such SoS mechanisms. It aims at providing such incentives to the independently operated and managed constituents. This paper presents a systematic literature review on the applications of game theory to SoS engineering, together with a synthesis aiming at capturing the best practices for such an analysis. The main conclusions are that game theory can be applied to SoS in a wide range of application areas, and deal with problems related to acquisition, design, and operations. In particular, the operational formation of SoS are well suited for this kind of analysis, and this often requires the use of simulation techniques. However, most results in the field lack a validation in practice.

  • 127.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Needs and Architectural Strategies Related to Geospatial Information in Systems-of-Systems2020In: SOSE 2020 - IEEE 15th International Conference of System of Systems Engineering, Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2020, p. 111-116, article id 9130532Conference paper (Refereed)
    Abstract [en]

    This paper puts forward the hypothesis that all systems-of-systems (SoS) need to deal with geospatial information. It discusses some fundamental aspects of such geodata, including entities, coordinate systems, features, and representation. It then presents how geodata can be used for various purposes in SoS and suggests architectural strategies for handling geodata in this context, including the use of linked data to represent both geodata and other information; triple stores for databases; and cloud servers for executing geodata related constituent system functionality.

  • 128.
    Axelsson, Jakob
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Systems-of-Systems Engineering Online Education: An Experience Report2020In: SOSE 2020 - IEEE 15th International Conference of System of Systems Engineering, Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2020, p. 87-92, article id 9130518Conference paper (Refereed)
    Abstract [en]

    Online education is changing how teaching is done at universities and provides new opportunities to reach out to practitioners. In this paper, the development of an online course in systems-of-systems engineering is presented, as well as results from the first instance of the course. The paper describes how the course was designed; how it was produced; and experiences from giving it. Challenges with online education in the systems engineering subjects are also highlighted.

  • 129.
    Axelsson, Jakob
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Eriksson, Peter
    Blue Institute, Västerås, Sweden.
    Higher-Level Capabilities of System-of-Systems Constituents: A Case of Industrial Ecosystems2023In: 2023 18th Annual System of Systems Engineering Conference, SoSe 2023, Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
    Abstract [en]

    In a system-of-systems, independent constituent systems collaborate to achieve broader capabilities they cannot provide on their own. This paper investigates the nature of the constituent system capabilities beyond basic operational actions, to achieve a deeper understanding of what is required to participate in a system-of-systems. Through a case study of industrial ecosystems, the need is shown for planning how to use basic operational capabilities, for dynamic capabilities to achieve long-term evolution, and for resilience capabilities to deal with perturbations. This also affects the governance of the system. The findings are used to extend an existing conceptual model of constituent systems and to characterize collaboration in a system-of-systems that implements a value network. 

  • 130.
    Axelsson, Jakob
    et al.
    Swedish Institute of Computer Science, SICS, Sweden.
    Franke, Ulrik
    Swedish Institute of Computer Science, SICS, Sweden.
    Carlson, Jan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sentilles, Séverine
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Cicchetti, Antonio
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards the Architecture of a Decision Support Ecosystem for System Component Selection2017In: 11th Annual IEEE International Systems conference SysCon17, 2017, p. 371-377Conference paper (Refereed)
    Abstract [en]

    When developing complex software-intensive systems, it is nowadays common practice to base the solution partly on existing software components. Selecting which components to use becomes a critical decision in development, but it is currently not well supported through methods and tools. This paper discusses how a decision support system for this problem could benefit from a software ecosystem approach, where participants share knowledge across organizations both through reuse of analysis models, and through partially disclosed past decision cases. It is shown how the architecture of this ecosystem becomes fundamental to deal with efficient knowledge sharing, while respecting constraints on integrity of intellectual property. A concrete proposal for an architecture is outlined, which is a distributed system-of-systems using web technologies. Experiences of a proof-of-concept implementation are also described.

  • 131.
    Axelsson, Jakob
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. RISE, SICS,Västerås,Sweden.
    Fröberg, Joakim
    RISE, SICS,Västerås,Sweden.
    Eriksson, Peter
    Blue Institute, Västerås, Sweden.
    Architecting systems‐of‐systems and their constituents: A case study applying Industry 4.0 in the construction domain2019In: Systems Engineering, ISSN 1098-1241, E-ISSN 1520-6858, Vol. 22, no 6, p. 455-470Article in journal (Refereed)
    Abstract [en]

    The development of system‐of‐systems (SoS) requires a continuous interplay between design decisions on the SoS level and those on the level of its constituent systems (CS), which often preexist and need to be adapted as the SoS evolves. This involves not only preparing the CS to participate in a particular SoS, but also designing the CS architecture to make it easily adaptable to a future SoS context. The problem is in part addressed in an emerging SoS framework in the manufacturing domain called Industry 4.0. It focuses on connected and digitalized production with the ambition of increasing flexibility and efficiency. This paper investigates how Industry 4.0 standards can be used in an SoS context to make CS more flexible and adaptive, and evaluates their usefulness outside manufacturing. The study is based on a case from the construction domain, for which a generic SoS architecture is developed. Several extensions and adaptations of Industry 4.0 are suggested, including specifications of ontologies for missions and workflows.

  • 132.
    Axelsson, Jakob
    et al.
    RISE SICS AB, Kista, Sweden.
    Nylander, Stina
    RISE SICS AB, Kista, Sweden.
    An Analysis of Systems-of-Systems Opportunities and Challenges Related to Mobility in Smart Cities2018In: System of Systems Engineering Conference SoSE 2018, 2018, p. 132-137Conference paper (Refereed)
    Abstract [en]

    Urbanization is one of the major current trends in society. Cities around the world are looking into 'smart'  solutions based on information and communication technology to deal with the challenges that result from this development. Mobility is one of the most important areas to address, and system-of-systems solutions where vehicles and infrastructure are connected have a potential to improve urban transportation in many aspects. In this paper, current initiatives related to mobility in smart cities around the world are surveyed, and this is complemented with input from focus groups of transportation stakeholders to identify the important aspects of the problem. Based on this, challenges related to the application of systems-of-systems in urban mobility are identified.

  • 133.
    Axelsson, Jakob
    et al.
    SICS Swedish ICT, Sweden.
    Papatheocharous, Efi
    SICS Swedish ICT, Sweden.
    Nyfjord, Jaana
    SICS Swedish ICT, Sweden.
    Törngren, Martin
    KTH Royal Institute of Technology, Sweden.
    Notes On Agile and Safety-Critical Development2016In: Software Engineering Notes: an Informal Newsletter of The Specia, ISSN 0163-5948, E-ISSN 1943-5843, Vol. 41, no 2, p. 23-26Article in journal (Refereed)
    Abstract [en]

    Agile approaches have been highly influential to the software engineering practices in many organizations, and are increasingly being applied in larger companies, and for developing systems outside the pure software domain. To understand more about the current state of agile, its applications to safety-critical systems, and the consequences on innovation and large organizations, a seminar was organized in Stockholm in 2014. This paper gives an overview of the topics discussed at that seminar, a summary of the main results and suggestions for future work as input to a research agenda for agile development of safety-critical software.

  • 134.
    Ayala, Inmaculada
    et al.
    ITIS Software Universidad de Málaga, Málaga, Spain.
    Amor, Mercedes
    ITIS Software Universidad de Málaga, Málaga, Spain.
    Fuentes, Lidia
    ITIS Software Universidad de Málaga, Málaga, Spain.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Self-adapting Industrial Augmented Reality applications with proactive Dynamic Software Product Lines2021In: 26th IEEE International Conference on Emerging Technologies and Factory Automation ETFA 2021, Institute of Electrical and Electronics Engineers (IEEE), 2021Conference paper (Refereed)
    Abstract [en]

    Industrial Augmented Reality (IAR) is a key enabling technology for Industry 4.0. However, its adoption poses several challenges because it requires the execution of computing-intensive tasks in devices with poor computational resources, which contributes to a faster draining of the device batteries. Proactive self-adaptation techniques could overcome these problems that affect the quality of experience by optimizing computational resources and minimizing user disturbance. In this work, we propose to apply ProDSPL, a proactive Dynamic Software Product Line, for the self-adaptation of IAR applications to satisfy the quality requirements. ProDSPL is compared against MODAGAME, a multi-objective DSPL approach that uses a genetic algorithm to generate quasi-optimal feature model configurations at runtime. The evaluation with randomly generated feature models running on mobile devices shows that ProDSPL gives results closer to the Pareto optimal than MODAGAME.

  • 135.
    Ayala, Inmaculada
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Gallina, Barbara
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards Tool-based Security-informed Safety Oriented Process Line Engineering2016In: 1st International workshop on Interplay of Security, Safety and System/Software Architecture ISSA-2016, 2016, article id 38Conference paper (Refereed)
    Abstract [en]

    For the purpose of certification, manufactures of nowadays highly connected safety-critical systems are expected to en- gineer their systems according to well-defined engineering processes in compliance with safety and security standards. Certification is an extremely expensive and time-consuming process. Since safety and security standards exhibit a certain degree of commonality, certification-related artifacts (e.g., process models) should to some extent be reusable. To en- able systematic reuse and customization of process infor- mation, in this paper we further develop security-informed safety-oriented process line engineering (i.e., engineering of sets of processes including security and safety concerns). More specifically, first we consider three tool-supported ap- proaches for process-related commonality and variability man- agement and we apply them to limited but meaningful por- tions of safety and security standards within airworthiness. Then, we discuss our findings. Finally, we draw our conclu- sions and sketch future work.

  • 136.
    Ayala, Inmaculada
    et al.
    Universidad de Málaga, Málaga, Spain.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Amor, Mercedes
    Universidad de Málaga, Málaga, Spain.
    Fuentes, Lidia
    Universidad de Málaga, Málaga, Spain.
    ProDSPL: Proactive Self-Adaptation Based on Dynamic Software Product Lines2021In: Proceedings of the 25th ACM International Systems and Software Product Line Conference - Volume A, Association for Computing Machinery , 2021Conference paper (Refereed)
    Abstract [en]

    This is an extended abstract of the article: Inmaculada Ayala, Alessandro V. Papadopoulos, Mercedes Amor, Lidia Fuentes, ProDSPL: Proactive self-adaptation based on Dynamic Software Product Lines, Journal of Systems and Software, Volume 175, 2021, 110909, ISSN 0164-1212, https://doi.org/10.1016/j.jss.2021.110909.

  • 137.
    Aysan, Hüseyin
    Mälardalen University, School of Innovation, Design and Engineering.
    Fault-Tolerance Strategies and Probabilistic Guarantees for Real-Time Systems2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Ubiquitous deployment of embedded systems is having a substantial impact on our society, since they interact with our lives in many critical real-time applications. Typically, embedded systems used in safety or mission critical applications (e.g., aerospace, avionics, automotive or nuclear domains) work in harsh environments where they are exposed to frequent transient faults such as power supply jitter, network noise and radiation. They are also susceptible to errors originating from design and production faults. Hence, they have the design objective to maintain the properties of timeliness and functional correctness even under error occurrences.

    Fault-tolerance plays a crucial role towards achieving dependability, and the fundamental requirement for the design of effective and efficient fault-tolerance mechanisms is a realistic and applicable model of potential faults and their manifestations. An important factor to be considered in this context is the random nature of faults and errors, which, if addressed in the timing analysis by assuming a rigid worst-case occurrence scenario, may lead to inaccurate results. It is also important that the power, weight, space and cost constraints of embedded systems are addressed by efficiently using the available resources for fault-tolerance.

    This thesis presents a framework for designing predictably dependable embedded real-time systems by jointly addressing the timeliness and the reliability properties. It proposes a spectrum of fault-tolerance strategies particularly targeting embedded real-time systems. Efficient resource usage is attained by considering the diverse criticality levels of the systems' building blocks. The fault-tolerance strategies are complemented with the proposed probabilistic schedulability analysis techniques, which are based on a comprehensive stochastic fault and error model.

    Download full text (pdf)
    fulltext
  • 138.
    Aysan, Hüseyin
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Dobrin, Radu
    Mälardalen University, Department of Computer Science and Electronics.
    Punnekkat, Sasikumar
    Mälardalen University, Department of Computer Science and Electronics.
    A Generalized Task Allocation Framework for Dependable Real-Time Systems2007In: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS 07), 2007Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a general framework which allows the designer to specify a wide range of criteria for allocation. Major factors considered as part of our framework are mixed criticalities of tasks, schedulability, power consumption, fault-tolerance, and dependability requirements in addition to typical functional aspects such as memory constraints. This being a global optimization problem, we are forced to use meta-heuristic algorithms, and we were able to represent these requirements in a very intuitive manner by the usage of energy functions in simulated annealing. We envision the proposed methodology as a quite simple, scalable, as well as computationally effective solution covering a wide range of system architectures and solution spaces. 

  • 139.
    Aysan, Hüseyin
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Dobrin, Radu
    Mälardalen University, Department of Computer Science and Electronics.
    Punnekkat, Sasikumar
    Mälardalen University, Department of Computer Science and Electronics.
    FT-Feasibility in Fixed Priority Real-Time Scheduling2007Report (Other academic)
    Abstract [en]

    Real-time systems typically have to satisfy complex requirements mapped to the timing attributes of the tasks that are eventually guaranteed by the underlying scheduler. These systems consist of a mix of hard and soft tasks with varying criticalities as well as associated fault tolerance (FT) requirements. Often time redundancy techniques are preferred in many embedded applications and hence it is extremely important to devise appropriate methodologies for scheduling real-time tasks under fault assumptions. Additionally, the relative criticality of tasks could undergo changes during the evolution of the system. Hence scheduling decisions under fault assumptions have to reflect all these important factors in addition to the resource constraints.

    In this paper we propose a framework for 'FTfeasibility', i.e., to provide a priori guarantees that all critical tasks in the system will meet their deadlines even in case of faults. Our main objective here is to ensure FTfeasibility of all critical tasks in the system and do so with minimal costs and without any fundamental changes in the scheduling paradigm. We demonstrate its applicability in scenarios where the FT strategy employed is re-execution of the affected tasks or an alternate action upon occurrence of transient faults or software design faults. We analyse a feasible set of tasks and propose methods to adapt it to varying FT requirements without modifications to the underlying scheduler. We do so by reassigning task attributes to achieve FT-feasibility while keeping the costs minimised.

  • 140.
    Aysan, Hüseyin
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Punnekkat, Sasikumar
    Mälardalen University, School of Innovation, Design and Engineering.
    A Generalised Error Model and Schedulability Guarantees for Dependable Real-Time Systems2011In: Proceedings of the 1st International Workshop on Dependable and Secure Industrial and Embedded Systems (WORDS), 2011Conference paper (Refereed)
    Abstract [en]

    The fundamental requirement for the design of effective and efficient fault-tolerance mechanisms in dependable real-time systems is a realistic and applicable model of potential faults, their manifestations and consequences. Fault and error models also need to be evolved based on the changes in the environments of usage or even based on technological advances. In this paper we propose a novel probabilistic burst error model in lieu of the commonly used simplistic fault assumptions. We introduce an approach to reason about real-time systems schedulability under the proposed error model in a probabilistic manner. We first present a sufficient analysis that accounts for the worst case interference caused by error bursts on the response times of tasks scheduled under the fixed priority scheduling (FPS) policy. Further, we identify potential sources of pessimism in the calculations and propose an algorithm that refines the results.

  • 141.
    Back, Ralph-Johan
    et al.
    Turku Centre for Computer Science .
    Cerschi (Seceleanu), Cristina
    Turku Centre for Computer Science .
    Modeling and Verifying a Temperature Control System using Continuous Action Systems2000Conference paper (Refereed)
    Abstract [en]

    We formally describe and verify a real-time temperature control system for a nuclear reactor tank, using a generalization of action systems to hybrid systems (based on weakest precondition predicate transformer semantics) as our formal framework. The analyzed control system is a linear hybrid system, combining discrete control with continuous dynamics. Our work can be seen as a case study on the applicability of the hybrid action system formalism to study the reachability problem, i.e., to prove that an unsafe state can not be reached by executing the system.

  • 142.
    Back, Ralph-Johan
    et al.
    Turku Centre for Computer Science, Finland.
    Seceleanu, Cristina
    Turku Centre for Computer Science, Finland.
    Westerholm, Jan
    Turku Centre for Computer Science, Finland.
    Symbolic Simulation of Hybrid Systems2002Conference paper (Refereed)
    Abstract [en]

    Continuous action systems (CAS) is a formalism intended for modeling hybrid systems (systems that combine discrete control with continuous behavior), and proving properties about the model within refinement calculus. In this paper we use a symbolic manipulation program to build a tool for simulating CAS models by calculating symbolically the time evolution of the discrete and continuous CAS model functions, as explicit and exact expressions of a continuous time variable. We may then study the time behavior and general properties of the model by plotting these functions with respect to time. For certain models our tool eliminates the need for introducing tolerances into the model structure. The tool is useful for checking that the model behaves correctly, and we can sometimes study the behavior of CAS models with in principle infinite precision.

  • 143.
    Backeman, Peter
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Kunnappilly, A.
    Alstom, Västerås, Sweden.
    Seceleanu, Cristina
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Supporting 5G Service Orchestration with Formal Verification2023In: Computer Science and Information Systems, ISSN 1820-0214, Vol. 29, no 1, p. 329-357Article in journal (Refereed)
    Abstract [en]

    The 5G communication technology has the ability to create logical net-works, called network slices, which are specifically carved to serve particular application domains. Due to the mix of different application criticality, it becomes crucial to verify if the applications’ service level agreements are met. In this pa-per, we propose a novel framework for modeling and verifying 5G orchestration, considering simultaneous access and admission of new requests to slices as well as virtual network function scheduling and routing. By combining modeling in user-friendly UML, with UPPAAL model checking and satisfiability-modulo-theories-based model finding, our framework supports both modeling and formal verification of service orchestration. We demonstrate our approach on a e-health case study showing how a user, with no knowledge of formal methods, can model a system in UML and verify that the application meets its requirements. © 2023, ComSIS Consortium. All rights reserved.

  • 144.
    Backeman, Peter
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rummer, Philipp
    Uppsala Univ, Dept Informat Technol, Uppsala, Sweden..
    Zeljic, Aleksandar
    Stanford Univ, Stanford, CA 94305 USA..
    Interpolating bit-vector formulas using uninterpreted predicates and Presburger arithmetic2021In: Formal methods in system design, ISSN 0925-9856, E-ISSN 1572-8102, Vol. 57, no 2, p. 121-156Article in journal (Refereed)
    Abstract [en]

    The inference of program invariants over machine arithmetic, commonly called bit-vector arithmetic, is an important problem in verification. Techniques that have been successful for unbounded arithmetic, in particular Craig interpolation, have turned out to be difficult to generalise to machine arithmetic: existing bit-vector interpolation approaches are based either on eager translation from bit-vectors to unbounded arithmetic, resulting in complicated constraints that are hard to solve and interpolate, or on bit-blasting to propositional logic, in the process losing all arithmetic structure. We present a new approach to bit-vector interpolation, as well as bit-vector quantifier elimination (QE), that works by lazy translation of bit-vector constraints to unbounded arithmetic. Laziness enables us to fully utilise the information available during proof search (implied by decisions and propagation) in the encoding, and this way produce constraints that can be handled relatively easily by existing interpolation and QE procedures for Presburger arithmetic. The lazy encoding is complemented with a set of native proof rules for bit-vector equations and non-linear (polynomial) constraints, this way minimising the number of cases a solver has to consider. We also incorporate a method for handling concatenations and extractions of bit-vector efficiently.

  • 145.
    Bagheri, M.
    et al.
    Sharif University of Technology, Tehran, Iran.
    Khamespanah, E.
    Sharif University of Technology, Tehran, Iran.
    Sirjani, Marjan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Reykjavik University, Reykjavik, Iceland.
    Movaghar, A.
    Sharif University of Technology, Tehran, Iran.
    Lee, A. E.
    University of California at Berkeley.
    Runtime compositional analysis of track-based traffic control systems2017In: ACM SIGBED Review, ISSN 1551-3688, Vol. 14, no 3, p. 38-39Article in journal (Refereed)
  • 146.
    Bagheri, M.
    et al.
    Sharif University of Technology, Tehran, Iran.
    Sirjani, Marjan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Reykjavik University, Reykjavik, Iceland.
    Khamespanah, E.
    Reykjavik University, Reykjavik, Iceland.
    Khakpour, N.
    Linnaeus University, Växjö Campus, Sweden.
    Akkaya, I.
    University of California at Berkeley, CA, United States.
    Movaghar, A.
    Sharif University of Technology, Tehran, Iran.
    Lee, E. A.
    University of California at Berkeley, CA, United States.
    Coordinated actor model of self-adaptive track-based traffic control systems2018In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 143, p. 116-139Article in journal (Refereed)
    Abstract [en]

    Self-adaptation is a well-known technique to handle growing complexities of software systems, where a system autonomously adapts itself in response to changes in a dynamic and unpredictable environment. With the increasing need for developing self-adaptive systems, providing a model and an implementation platform to facilitate integration of adaptation mechanisms into the systems and assuring their safety and quality is crucial. In this paper, we target Track-based Traffic Control Systems (TTCSs) in which the traffic flows through pre-specified sub-tracks and is coordinated by a traffic controller. We introduce a coordinated actor model to design self-adaptive TTCSs and provide a general mapping between various TTCSs and the coordinated actor model. The coordinated actor model is extended to build large-scale self-adaptive TTCSs in a decentralized setting. We also discuss the benefits of using Ptolemy II as a framework for model-based development of large-scale self-adaptive systems that supports designing multiple hierarchical MAPE-K feedback loops interacting with each other. We propose a template based on the coordinated actor model to design a self-adaptive TTCS in Ptolemy II that can be instantiated for various TTCSs. We enhance the proposed template with a predictive adaptation feature. We illustrate applicability of the coordinated actor model and consequently the proposed template by designing two real-life case studies in the domains of air traffic control systems and railway traffic control systems in Ptolemy II. 

  • 147.
    Bagheri, Maryam
    et al.
    Sharif University of Technology, Iran.
    Akkaya, Ilge
    University of California at Berkley, US.
    Khamespanah, Ehsan
    Reykjavik University, Iceland.
    Khakpour, Narges
    Linnaeus University, Sweden.
    Sirjani, Marjan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Movaghar, Ali
    Sharif University of Technology, Iran.
    Lee, Edward
    University of California at Berkley, US.
    Coordinated Actors for Reliable Self-Adaptive Systems2017In: The 13th International Conference on Formal Aspects of Component Software FACS 2016, 2017, Vol. 10231, p. 241-259Conference paper (Refereed)
    Abstract [en]

    Self-adaptive systems are systems that automatically adapt in response to environmental and internal changes, such as possible failures and variations in resource availability. Such systems are often realized by a MAPE-K feedback loop, where Monitor, Analyze, Plan and Execute components have access to a runtime model of the system and environment which is kept in the Knowledge component. In order to provide guarantees on the correctness of a self-adaptive system at runtime, the MAPE-K feedback loop needs to be extended with assurance techniques. To address this issue, we propose a coordinated actor-based approach to build a reusable and scalable model@runtime for self-adaptive systems in the domain of track-based traffic control systems. We demonstrate the approach by implementing an automated Air Traffic Control system (ATC) using Ptolemy tool.We compare different adaptation policies on the ATC model based on performance metrics and analyze combination of policies in different configurations of the model. We enriched our framework with runtime performance analysis such that for any unexpected change, subsequent behavior of the model is predicted and results are used for adaptation at the change-point. Moreover, the developed framework enables checking safety properties at runtime.

  • 148.
    Baig, Aftab
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Ahmad, Iftikhar
    Mälardalen University, School of Innovation, Design and Engineering.
    A web store based on reusable .NET components2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis project describes  the analysis, process and major factors in development of a simple component oriented Web Shop in ASP.NET. It addresses to the concepts used in  the application as  well  as  derivation  of  technical  design  and  development  from  the  concepts  acquired  by studying existing approaches.

    The report  describes  a  brief  summary of  existing  approaches  and related  technologies.  It also lays  the foundation  of  goal  oriented  approach  by  providing  an  overview  of  component  based  software engineering. The  basic  concepts for modularization  were  barrowed from  entities  identification,  object models and component models pplication’s architecture is set to be a layered app roach combining the software layered  architecture  approach  with  multi  tier  architecture  of  web  applications. Class models explaining the inner structure of each component have been provided and an overview of user interface pages is given to explain the application outer flow. The application sets out to prove the significance of component oriented approach as well as  the  support  provided for it by ASP.Net. The resulting package proves  to  have  scalable  components  that could be scaled for  or  reused in another  application or  in  a later version of the same application. 

    Download full text (pdf)
    Thesis report in the field of software engineering
  • 149.
    Bakhshi Valojerdi, Zeinab
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rodriguez-Navas, Guillermo
    Nokia Bell Labs, Israel.
    A preliminary roadmap for dependability research in fog computing2020In: ACM SIGBED Review, E-ISSN 1551-3688, Vol. 16, no 4, p. 14-19Article in journal (Refereed)
    Abstract [en]

    Fog computing aims to support novel real-time applications by extending cloud resources to the network edge. This technology is highly heterogeneous and comprises a wide variety of devices interconnected through the so-called fog layer. Compared to traditional cloud infrastructure, fog presents more varied reliability challenges, due to its constrained resources and mobility of nodes. This paper summarizes current research efforts on fault tolerance and dependability in fog computing and identifies less investigated open problems, which constitute interesting research directions to make fogs more dependable. 

  • 150.
    Bakhshi Valojerdi, Zeinab
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rodriguez-Navas, Guillermo
    Nokia Bell Labs, Israel.
    Hansson, Hans
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dependable Fog Computing: A Systematic Literature Review2019In: Proceedings - 45th Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2019, 2019, p. 395-403, article id 8906732Conference paper (Refereed)
    Abstract [en]

    Fog computing has been recently introduced to bridge the gap between cloud resources and the network edge. Fog enables low latency and location awareness, which is considered instrumental for the realization of IoT, but also faces reliability and dependability issues due to node mobility and resource constraints. This paper focuses on the latter, and surveys the state of the art concerning dependability and fog computing, by means of a systematic literature review. Our findings show the growing interest in the topic but the relative immaturity of the technology, without any leading research group. Two problems have attracted special interest: guaranteeing reliable data storage/collection in systems with unreliable and untrusted nodes, and guaranteeing efficient task allocation in the presence of varying computing load. Redundancy-based techniques, both static and dynamic, dominate the architectures of such systems. Reliability, availability and QoS are the most important dependability requirements for fog, whereas aspects such as safety and security, and their important interplay, have not been investigated in depth.

    Download full text (pdf)
    fulltext
1234567 101 - 150 of 1454
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf