liu.seSearch for publications in DiVA
Change search
Refine search result
123 1 - 50 of 110
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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.
  • 1.
    Almquist, Mathias
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Almquist, Viktor
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Communication Energy Overhead of Mobiles Games2015In: MobiGames '15: Proceedings of the 2nd Workshop on Mobile Gaming, Association for Computing Machinery (ACM), 2015, p. 1-6Conference paper (Other academic)
    Abstract [en]

    Although a significant proportion of the mobile apps are games there has been little attention paid to their specific characteristics with respect to communication energy. In this paper we select 20 mobile games among the top 100 free Android games, and study their data patterns and communication energy use over a total of 25 hours of playing. The analysis of the energy for communication over 3G networks indicates that there is a wide variation among the games, the largest footprint being 8 times higher than the lowest one. The results also indicates both app-specific and category-specific relations between data pattern and energy use, as well as variations in CPU utilisation.

  • 2.
    Amirijoo, Mehdi
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Tesanovic, Aleksandra
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Raising Motivation in Real-time Laboratories: The Soccer Scenario2004In: Technical Symposium on Computer Science Education, SIGCSE,2004, USA: Association for Computing Machinery (ACM) , 2004, p. 265-Conference paper (Refereed)
    Abstract [en]

    Real-time systems is a topic that one cannot overlook in an engineer's education. However, teaching real-time systems in an undergraduate syllabus is a challenging experience due to conflicting constraints placed on such a course. In this paper we present a new setup for laboratories in the real-time systems course that successfully meets the constraints of mass education, stable environment management, short time span for the labs, and still enables deep involvement of students in the central topic of resource allocation with high motivation.

  • 3.
    Asplund, Mikael
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    de Lanerolle, Trishan
    Trinity College, Hartford, CT, USA.
    Fei, Christopher
    Trinity College, Hartford, CT, USA.
    Gautam, Prasanna
    Trinity College, Hartford, CT, USA.
    Morelli, Ralph
    Trinity College, Hartford, CT, USA.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nykvist, Gustav
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Wireless Ad Hoc Dissemination for Search and Rescue2010In: Proceedings of the 7th International ISCRAM Conference / [ed] Simon French, Brian Tomaszewski, Christopher Zobel, ISCRAM , 2010Conference paper (Refereed)
    Abstract [en]

    In search and rescue scenarios local information on victims and other finds needs to be disseminated rapidly toother rescue workers and team leaders. However, post disaster scenarios may imply the collapse of informationinfrastructure including cellular communication and Internet connectivity. Even if we consider wireless ad hoccommunication as a means of information dissemination we should count on frequent loss of connectivity in thenetwork due to unpredictable mobility and sparse network topologies. In this paper we present the realization ofan existing manycast protocol (random walk gossip) on commodity handheld devices running the Androidplatform. This communication mode is used to demonstrate the potential for distributed informationdissemination on victims and finds. The application layer is an adaptation of an existing surveying informationtool (POSIT) which is now fully decentralized and relies on text communication to achieve energy efficiency.

  • 4.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    A Partition-tolerant Manycast Algorithm for Disaster Area Networks2009In: 28TH IEEE INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS, PROCEEDINGS, IEEE Computer Society, 2009, p. 156-165Conference paper (Refereed)
    Abstract [en]

    Information dissemination in disaster scenarios requires timely and energy-efficient communication in intermittently connected networks. When the existing infrastructure is damaged or overloaded, we suggest the use of a manycast algorithm that runs over a wireless mobile ad hoc network, and overcomes partitions using a store-and-forward mechanism. This paper presents a random walk gossip protocol that uses an efficient data structure to keep track of already informed nodes with minimal signalling. Avoiding unnecessary transmissions also makes it less prone to overloads. Experimental evaluation shows higher delivery ratio, lower latency, and lower overhead compared to a recently published algorithm.

  • 5.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Analysing Delay-tolerant Networks with Correlated Mobility2012In: Ad-hoc, Mobile, and Wireless Networks: 11th International Conference, ADHOC-NOW 2012, Belgrade, Serbia, July 9-11, 2012. Proceedings / [ed] Xiang-Yang Li, Symeon Papavassiliou, Stefan Ruehrup, Springer , 2012, p. 83-97Conference paper (Refereed)
    Abstract [en]

    This book constitutes the refereed proceedings of the 11th International Conference on Ad-hoc, Mobile, and Wireless Networks, ADHOC-NOW 2012 held in Belgrade, Serbia, July 9-11, 2012. The 36 revised full papers presented were carefully reviewed and selected from 76 submissions. The accepted papers cover a wide spectrum of traditional networking topics ranging from routing to the application layer, to localization in various networking environments such as wireless sensor and ad-hoc networks, and give insights in a variety of application areas.

  • 6.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Attitudes and Perceptions of IoT Security in Critical Societal Services2016In: IEEE Access, E-ISSN 2169-3536, Vol. 4, p. 2130-2138Article in journal (Refereed)
    Abstract [en]

    A quiet revolution that impacts several sectors, ranging over transport, home automation, energy, industrial control, and health services is undergoing with addition of new networked devices leading to enhanced services. In this paper, we aim to identify information security requirements that are common over several (vertical) sectors, and in particular, ones that impact critical societal services, namely, the energy, water, and health management systems. We present the results of an interview-based study where actors in these sectors were asked about their perceptions and attitudes on the security of Internet of Things (IoT). We set these perceptions and attitudes in context through a literature review of IoT security, and relate to current challenges in this area. This paper demonstrates that despite an overall optimistic view on IoT in critical societal services, there is a lack of consensus on risks related to IoT security.

  • 7.
    Asplund, Mikael
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Formalising Reconciliation in Partitionable Networks with Distributed Services2006In: Rigorous Development of Complex Fault-Tolerant Systems / [ed] Michael Butler, Cliff Jones, Alexander Romanovsky, Elena Troubitsyna, Heidelberg: Springer Verlag , 2006, p. 37-58Chapter in book (Other academic)
    Abstract [en]

    This book brings together 19 papers focusing on the application of rigorous design techniques to the development of fault-tolerant, software-based systems. It is an outcome of the REFT 2005 Workshop on Rigorous Engineering of Fault-Tolerant Systems held in conjunction with the Formal Methods 2005 conference at Newcastle upon Tyne, UK, in July 2005.

  • 8.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Post-Partition Reconciliation Protocols for Maintaining Consistency2006Conference paper (Refereed)
    Abstract [en]

    This paper addresses design exploration for protocols thatare employed in systems with availability-consistency tradeoffs. Distributed data is modelled as states of objects replicated across a network, and whose updates require satisfaction of integrity constraints over multiple objects. Upondetection of a partition, such a network will continue toprovide delivery of services in parallel partitions; but onlyfor updates with non-critical integrity constraints. Once thedegraded mode ends, the parallel network partitions are reconciled to arrive at one partition.Using a formal treatment of the reconciliation process,three algorithms are proposed and studied in terms of theirinfluence on service outage duration. The longer the reconciliation time, the lower is system availability; since theinterval in which no services are provided is longer. However, the reconciliation time in turn is affected by the time toconstruct the post-partition system state. The shorter theconstruction time the higher is the number of updates thattook place in the degraded mode but that will not be takenup in the reconciled partition. This will lead to a longerinterval for rejecting/redoing these operations and therebyincrease reconciliation time.

  • 9.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Post-Partition Reconciliation Protocols for Maintaning Consistency2006In: SAC '06 Proceedings of the 2006 ACM symposium on Applied computing, New York, NY, USA: ACM Press, 2006, p. 710-717Conference paper (Refereed)
    Abstract [en]

    This paper addresses design exploration for protocols that are employed in systems with availability-consistency trade-offs. Distributed data is modelled as states of objects replicated across a network, and whose updates require satisfaction of integrity constraints over multiple objects. Upon detection of a partition, such a network will continue to provide delivery of services in parallel partitions; but only for updates with non-critical integrity constraints. Once the degraded mode ends, the parallel network partitions are reconciled to arrive at one partition. Using a formal treatment of the reconciliation process, three algorithms are proposed and studied in terms of their influence on service outage duration. The longer the reconciliation time, the lower is system availability; since the interval in which no services are provided is longer. However, the reconciliation time in turn is affected by the time to construct the post-partition system state. The shorter the construction time the higher is the number of updates that took place in the degraded mode but that will not be taken up in the reconciled partition. This will lead to a longer interval for rejecting/redoing these operations and thereby increase reconciliation time.

  • 10.
    Asplund, Mikael
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Random walk gossip-based manycast with partition detection2008In: Supplemental Proceedings of the International Conference on Dependable Systems and Networks, DSN, 2008, IEEE Computer Society , 2008, p. G40-G41Conference paper (Other academic)
    Abstract [en]

       

  • 11.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Rapid selection and dissemination of urgent messages over delay-tolerant networks (DTNs)2015In: Advances in Delay-Tolerant Networks (DTNs): Architecture and Enhanced Performance / [ed] J. Rodrigues, Elsevier, 2015, p. 187-203Chapter in book (Refereed)
    Abstract [en]

    Today many new applications are emerging that take advantage of wireless communication in handheld and embedded devices. Some of these emerging applications, such as information sharing in vehicular systems, have strong requirements for timely message dissemination, even if the network is not always 100% connected. In this chapter we discuss message differentiation mechanisms that can be used in intermittently connected networks to improve delivery and latency properties when messages have a limited time to live in the network. We present a simulation-based study on a large-scale vehicular scenario comparing different prioritisation mechanisms for a partition-tolerant manycast protocol. We show that negative effects of overloads can be significantly reduced by using information within the message about how far it has spread and how much time is remaining.

  • 12.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Worst-case latency of broadcast in intermittently connected networks2012In: International Journal of Ad Hoc and Ubiquitous Computing, ISSN 1743-8225, E-ISSN 1743-8233, Vol. 11, no 2-3, p. 125-138Article in journal (Refereed)
    Abstract [en]

    Worst-case latency is an important characteristic of information dissemination protocols. However, in sparse mobile ad hoc networks where end-to-end connectivity cannot be achieved and store-carry-forward algorithms are needed, such worst-case analyses have not been possible to perform on real mobility traces due to lack of suitable models. We propose a new metric called delay expansion that reflects connectivity and reachability properties of intermittently connected networks. Using the delay expansion, we show how bounds on worst-case latency can be derived for a general class of broadcast protocols and a wide range of real mobility patterns. The paper includes theoretical results that show how worst-case latency can be related with delay expansion for a given mobility scenario, as well as simulations to validate the theoretical model.

  • 13.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Beyer, Stefan
    Instituto Tecnolgico Informtica Universidad Politcnica de Valencia, Spain.
    Galdamez, Pablo
    Instituto Tecnolgico Informtica Universidad Politcnica de Valencia, Spain.
    Measuring Availability in Optimistic Partition-Tolerant Systems with Data Constraints2007In: Dependable Systems and Networks, DSN 2007, IEEE Computer Society, 2007, p. 656-665Conference paper (Refereed)
    Abstract [en]

    Replicated systems that run over partitionable environments, can exhibit increased availability if isolated partitions are allowed to optimistically continue their execution independently. This availability gain is traded against consistency, since several replicas of the same objects could be updated separately. Once partitioning terminates, divergences in the replicated state needs to be reconciled. One way to reconcile the state consists of letting the application manually solve inconsistencies. However, there are several situations where automatic reconciliation of the replicated state is meaningful. We have implemented replication and automatic reconciliation protocols that can be used as building blocks in a partition-tolerant middleware. The novelty of the protocols is the continuous service of the application even during the reconciliation process. A prototype system is experimentally evaluated to illustrate the increased availability despite network partitions.

  • 14.
    Asplund, Mikael
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Sigholm, Johan
    Swedish National Defence College.
    Emerging Information Infrastructures: Cooperation in Disasters2009In: Critical Information Infrastructure Security: Third International Workshop, CRITIS 2008, Rome, Italy, October13-15, 2008. Revised Papers / [ed] Roberto Setola, Stefan Geretshuber, Springer Berlin/Heidelberg, 2009, p. 258-270Conference paper (Refereed)
    Abstract [en]

      In this paper we describe how to include high level semantic information, such as aesthetics and emotions; into Content Based Image Retrieval. We present a, color-based emotion-related image descriptor that can be used for describing the emotional content of images. The color emotion metric used is derived from psychophysical experiments rind based oil three variables: activity, weight and teat. It was originally designed for single-colors, bill, recent research has shown that the salve emotion estimates call be applied in the retrieval of multi-colored images. Here we describe a new approach, based oil the assumption that perceived color emotions in images are mainly affected by homogenous regions, defined by the emotion metric; and transitions between regions. RGB coordinates are converted to emotion coordinates, mid for each emotion channel, statistical measurements of gradient magnitudes within a. stack of low-pass filtered images are used for finding interest; points corresponding to homogeneous regions and transitions between regions. Emotion characteristics are derived for patches surrounding cacti interest, point, and saved in a, bag-of-emotions; that for instance, can be used for retrieving images based oil emotional content.

  • 15.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Zagar, Klemen
    Cosylab.
    Middleware extensions that trade consistency for availability2009In: CONCURRENCY AND COMPUTATION-PRACTICE and EXPERIENCE, ISSN 1532-0626, Vol. 21, no 9, p. 1181-1203Article in journal (Refereed)
    Abstract [en]

    Replicated distributed object systems are deployed to provide timely and reliable services to actors at distributed locations. This paper treats applications in which data updates are dependent on satisfaction of integrity constraints over multiple objects. Network partitions, caused by occasional link failures, overload or attacks create problems in keeping both consistency and availability in such networks. We propose a means of achieving higher availability by providing partition-awareness in middleware. The general approach has been illustrated by implementing a number of CORBA extensions that trade consistency for availability during network partitions. This paper contains a thorough experimental evaluation that presents the gains and costs of our approach. The experiments clearly illustrate the benefit of our protocols in terms of significantly higher availability and the number of performed operations.

  • 16.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Thomasson, Anton
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Software-related Energy Footprint of a Wireless Broadband Module2011In: The 9th ACM International Symposium on Mobility Management and Wireless Access (MobiWac), ACM , 2011Conference paper (Refereed)
    Abstract [en]

    Energy economy in mobile devices is becoming an increasinglyimportant factor as the devices become more advancedand rich in features. A large part of the energy footprint of amobile device comes from the wireless communication module,and even more so as the amount of trac increases.In this paper we study the energy footprint of a mobilebroadband hardware module, and how it is aected by software,by performing systematic power consumption measurements.We show that there are several cases where thesoftware does not properly take into account the eect thatdata communication has on the power consumption. Thisopens up for potential energy savings by creating better applicationsthat are aware of the energy characteristics of thecommunication layer.

  • 17.
    Bianzino, Aruna Prem
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Cooperative proxies: Optimally trading energy and quality of service in mobile devices2014In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 75, no Part A, p. 297-312Article in journal (Refereed)
    Abstract [en]

    This work studies the energy and quality of service (QoS) trade-off in the context of mobile devices with two communication interfaces (a high energy and a low energy interface). We propose an optimisation scheme during underload scenarios where proxy groups are dynamically formed exploiting both interfaces. The scheme integrates a reward mechanism that compensates a proxy while carrying other group members’ traffic, and deals with churn (joining and leaving of nodes) in a cell area. For traffic flows that approximate knowledge about current services we show that the scheme can achieve energy savings of 60% for all mobile nodes as whole. We also demonstrate the impact on disruption-sensitive flows as a function of the traffic mix, and that the use of rewards for selection of proxies is a fair mechanism in the long term.

  • 18.
    Burbeck, Kalle Ring
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Andres, S.G.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Semling, M.
    Dagonnier, T.
    Time as a Metric for Defence in Survivable Networks2003In: Real-Time Systems Symposium RTSS Work in Progress session,2003, 2003Conference paper (Refereed)
  • 19.
    Burbeck, Kalle Ring
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Garpe, Daniel
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Scale-up and Performance Studies of Three Agent Platforms2004In: International Performance, Communication and Computing Conference, Middleware Performance workshop,2004, 2004, p. 857-Conference paper (Refereed)
  • 20.
    Burbeck, Kalle Ring
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Adaptive Real-time Anomaly Detection with Incremental Clustering2007In: Information Security Technical Report, ISSN 1363-4127, E-ISSN 1873-605X, Vol. 12, p. 56-67Article in journal (Refereed)
  • 21.
    Burbeck, Kalle Ring
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    ADWICE: Anomaly Detection with Real-time Incremental Clustering2004In: International Conference on Information Security and Cryptology,2004, sss: Springer Verlag , 2004Conference paper (Refereed)
  • 22.
    Burbeck, Kalle Ring
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    ADWICE - Anomaly detection with real-time incremental clustering2005In: Information Security and Cryptology - ICISC 2004: 7th International Conference, Seoul, Korea, December 2-3, 2004, Revised Selected Papers / [ed] Choon-sik Park and Seongtaek Chee, Springer Berlin/Heidelberg, 2005, Vol. 3506, p. 407-424Chapter in book (Refereed)
    Abstract [en]

    Anomaly detection, detection of deviations from what is considered normal, is an important complement to misuse detection based on attack signatures. Anomaly detection in real-time places hard requirements on the algorithms used, making many proposed data mining techniques less suitable. ADWICE (Anomaly Detection With fast Incremental Clustering) uses the first phase of the existing BIRCH clustering framework to implement fast, scalable and adaptive anomaly detection. We extend the original clustering algorithm and apply the resulting detection mechanism for analysis of data from IP networks. The performance is demonstrated on the KDD data set as well as on data from a test network at a telecom company. Our experiments show a good detection quality (95 %) and acceptable false positives rate (2.8 %) considering the online, real-time characteristics of the algorithm. The number of alarms is then further reduced by application of the aggregation techniques implemented in the Safeguard architecture.

  • 23.
    Burguera, Iker
    et al.
    Electronics and Computing Department, Mondragon University.
    Zurutuza, Urko
    Electronics and Computing Department, Mondragon University.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Crowdroid: Behavior-Based Malware Detection Systemfor Android2011Conference paper (Refereed)
    Abstract [en]

    The sharp increase in the number of smartphones on themarket, with the Android platform posed to becoming amarket leader makes the need for malware analysis on thisplatform an urgent issue.In this paper we capitalize on earlier approaches for dynamicanalysis of application behavior as a means for detectingmalware in the Android platform. The detector is embeddedin a overall framework for collection of traces from anunlimited number of real users based on crowdsourcing. Ourframework has been demonstrated by analyzing the datacollected in the central server using two types of data sets:those from articial malware created for test purposes, andthose from real malware found in the wild. The method isshown to be an eective means of isolating the malware andalerting the users of a downloaded malware. This shows thepotential for avoiding the spreading of a detected malwareto a larger community.

  • 24.
    Chyssler, Tobias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Burschka, Stefan
    Software Security Technologies Swisscom Innovations.
    Burbeck, Kalle Ring
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Alarm Reduction and Correlation in Defence of IP Networks2004In: International Workshops on Enabling Technologies: Infrastructures for Collaborative Enterprises WETICE,2004, 2004Conference paper (Refereed)
  • 25.
    Cucurull, Jordi
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, Software and Systems.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Surviving Attacks in Challenged Networks2012In: IEEE Transactions on Dependable and Secure Computing, ISSN 1545-5971, E-ISSN 1941-0018, Vol. 9, no 6, p. 917-929Article in journal (Refereed)
    Abstract [en]

    In the event of a disaster, telecommunication infrastructures can be severely damaged or overloaded. Hastily formed networks can provide communication services in an ad hoc manner. These networks are challenging due to the chaotic context where intermittent connection is the norm and the identity and number of participants cannot be assumed. In such environments malicious actors may try to disrupt the communications to create more chaos for their own benefit. This paper proposes a general security framework for monitoring and reacting to disruptive attacks. It includes a collection of functions to detect anomalies, diagnose them, and perform mitigation. The measures are deployed in each node in a fully distributed fashion, but their collective impact is a significant resilience to attacks, so the actors can disseminate information under adverse conditions. The approach is evaluated in the context of a simulated disaster area network with a many-cast dissemination protocol, Random Walk Gossip, with a store-and-forward mechanism. A challenging threat model where adversaries may 1) try to drain the resources both at node level (battery life) and network level (bandwidth), or 2) reduce message dissemination in their vicinity, without spending much of their own energy, is adopted. The results demonstrate that the approach diminishes the impact of the attacks considerably.

  • 26.
    Cucurull, Jordi
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Anomaly detection and mitigation for disaster area networks2010In: Recent Advances in Intrusion Detection: 13th International Symposium, RAID 2010, Ottawa, Ontario, Canada, September 15-17, 2010. Proceedings / [ed] Somesh Jha, Robin Sommer and Christian Kreibich, Springer Berlin/Heidelberg, 2010, p. 339-359Chapter in book (Refereed)
    Abstract [en]

    One of the most challenging applications of wireless networking are in disaster area networks where lack of infrastructure, limited energy resources, need for common operational picture and thereby reliable dissemination are prevalent.In this paper we address anomaly detection in intermittently connected mobile ad hoc networks in which there is little or no knowledge about the actors on the scene, and opportunistic contacts together with a store-and-forward mechanism are used to overcome temporary partitions. The approach uses a statistical method for detecting anomalies when running a manycast protocol for dissemination of important messages to k receivers. Simulation of the random walk gossip (RWG) protocol combined with detection and mitigation mechanisms is used to illustrate that resilience can be built into a network in a fully distributed and attack-agnostic manner, at a modest cost in terms of drop in delivery ratio and additional transmissions. The approach is evaluated with attacks by adversaries that behave in a similar manner to fair nodes when invoking protocol actions.

  • 27.
    Cucurull, Jordi
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Raciti, Massimiliano
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Modular Anomaly Detection for Smartphone Ad Hoc Communication2012In: Information Security Technology for Applications: 16th Nordic Conference on Secure IT Systems, NordSec 2011, Tallinn, Estonia, October 26-28, 2011, Revised Selected Papers / [ed] Peeter Laud, Springer Berlin/Heidelberg, 2012, Vol. 7161, p. 65-81Conference paper (Refereed)
    Abstract [en]

    The capabilities of the modern smartphones make them the obvious platform for novel mobile applications. The open architectures, however, also create new vulnerabilities. Measures for prevention, detection, and reaction need to be explored with the peculiarities that resource-constrained devices impose. Smartphones, in addition to cellular broadband network capabilities, include WiFi interfaces that can even be deployed to set up a mobile ad hoc network (MANET). While intrusion detection in MANETs is typically evaluated with network simulators, we argue that it is important to implement and test the solutions in real devices to evaluate their resource footprint. This paper presents a modular implementation of an anomaly detection and mitigation mechanism on top of a dissemination protocol for intermittently-connected MANETs. The overhead of the security solution is evaluated in a small testbed based on three Android-based handsets and a laptop. The study shows the feasibility of the statistics-based anomaly detection regime, having low CPU usage, little added latency, and acceptable memory footprint.

  • 28.
    Curescu, C.
    et al.
    Ericsson Research, Torshamnsgatan 23, Kista, 164 83 Stockholm, Sweden.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    A bidding algorithm for optimized utility-based resource allocation in ad hoc networks2008In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 7, no 12, p. 1397-1414Article in journal (Refereed)
    Abstract [en]

    This paper proposes a scheme for bandwidth allocation in wireless ad hoc networks. The quality-of-service (QoS) levels for each end-to-end flow are expressed using a resource-utility function, and our algorithms aim to maximize aggregated utility. The shared channel is modeled as a bandwidth resource defined by maximal cliques of mutual interfering links. We propose a novel resource allocation algorithm that employs an auction mechanism in which flows are bidding for resources. The bids depend both on the flow's utility function and the intrinsically derived shadow prices. We then combine the admission control scheme with a utility-aware on-demand shortest path routing algorithm where shadow prices are used as a natural distance metric. As a baseline for evaluation, we show that the problem can be formulated as a linear programming (LP) problem. Thus, we can compare the performance of our distributed scheme to the centralized LP solution, registering results very close to the optimum. Next, we isolate the performance of price-based routing and show its advantages in hotspot scenarios, and also propose an asynchronous version that is more feasible for ad hoc environments. Further experimental evaluation compares our scheme with the state of the art derived from Kelly's utility maximization framework and shows that our approach exhibits superior performance for networks with increased mobility or less frequent allocations. © 2008 IEEE.

  • 29.
    Curescu, Calin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Price/Utility-based optimized resource allocation in wireless ad hoc networks2005In: The 2nd IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks SECON,,2005, Conference Proceedings: IEEE Communications Society , 2005, p. 85-Conference paper (Refereed)
    Abstract [en]

    This paper proposes a scheme for bandwidth allocation in wireless ad hoc networks. The Quality of Service (QoS) levels for each end-to-end flow are expressed using resource-utility functions, and our algorithms aim to maximise the aggregated utility of the flows. The scheme differentiates between applications with flexible resource requirements and rigid (real-time) requirements. As an abstract notion of resource, we use maximal cliques of mutual interfering links. Using concave piece-wise linear utility functions we present a linear programming (LP) formulation of the problem that can serve as an optimal though unrealistic solution. Then we replace this centralised approach with a distributed low complexity solution. A key concept, borrowed from the dual of the optimal allocation problem, is the shadow price of a resource. The contributions of the paper are twofold: (1) a distributed algorithm that allocates the bandwidth based on bids that are calculated using the shadow price of the resources and the flows utility function, (2) a utility-aware on-demand shortest path routing algorithm in which the shadow prices are used a natural distance metric. We compare the performance of the distributed allocation scheme with the centralised, optimal linear programming solution. We also compare with a non-utility-based QoS allocation scheme, that uses hop-based shortest path routing followed by highest possible bandwidth accommodation of the flow.

  • 30.
    Curescu, Calin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Time-aware Utility-based QoS Optimisation2003In: The 15th IEEE Euromicro Conference on Real-time Systems,2003, Conference Proceedings: IEEE Computer Society , 2003, p. 83-Conference paper (Refereed)
    Abstract [en]

    This paper presents a time-aware admission control and resource allocation scheme in the context of a future generation mobile network. The quality levels (and their respective utility) of the different connections are specified using discrete resource-utility (R-U) functions. The scheme uses these R-U functions for allocating and reallocating bandwidth to connections, aiming to maximise the accumulated utility of the system. However, different applications react differently to resource reallocations. Therefore at each allocation timepoint we take into account the following factors: the age of the connection, a drop (disconnection) penalty and the sensitiveness to reallocation frequency. Finally, we show the superior performance of our approach compared to a recent adaptive bandwidth allocation scheme.

  • 31.
    Curescu, Calin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Time-aware Utility-based Resource Allocation in Wireless Networks2005In: IEEE Transactions on Parallel and Distributed Systems, ISSN 1045-9219, E-ISSN 1558-2183, Vol. 16, no 7, p. 624-635Article in journal (Refereed)
    Abstract [en]

    This paper presents a time-aware admission control and resource allocation scheme in wireless networks in the context of a future generation cellular network. The quality levels (and their respective utility) of different connections are specified using discrete resource-utility (R-U) functions. The scheme uses these R-U functions for allocating and reallocating bandwidth to connections, aiming to maximize the accumulated utility of the system. However, different applications react differently to resource reallocations. Therefore, at each allocation time point, the following factors are taken into account: the age of the connection, a disconnection (drop) penalty, and the sensitiveness to reallocation frequency. The evaluation of our approach shows a superior performance compared to a recent adaptive bandwidth allocation scheme (RBBS). In addition, we have studied the overhead that performing a reallocation imposes on the infrastructure. To minimize this overhead, we present an algorithm that efficiently reduces the number of reallocations while remaining within a given utility bound.

  • 32.
    Curescu, Calin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Cao, Bing
    Computer Science Department, University of North Carolina at Charlotte, NC.
    Dahlberg, Teresa A.
    Computer Science Department, University of North Carolina at Charlotte, NC.
    Utility-based Adaptive Resource Allocation in Hybrid Wireless Networks2005In: The 2nd IEEE International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks QSHINE,2005, Conference Proceedings: IEEE Computer Society , 2005, p. 44-Conference paper (Refereed)
    Abstract [en]

    Service availability in wireless networks is highly dependent on efficient resource allocation and guaranteed Quality of Service (QoS) amid overloads and failures. This paper addresses optimal bandwidth allocation in a hybrid network (cellular and ad hoc), where added reach through an ad hoc overlay is combined with the stability and essential services of a cellular network. The paper builds on a near optimal approach in which Resource-Utility functions are used as a means of adaptive delivery of QoS, user differentiation, and maximisation of system level utility. It distinguishes between non-adaptive, semi-adaptive, and fully adaptive applications. First, the global cellular bandwidth allocation (in the presence of multiple routes through ad hoc relays) is cast in terms of a Linear Programming problem. Second, a heuristic algorithm that has far lower computational overhead and accrues at worse 12% less than the utility of the optimal solution is presented. Both algorithms are implemented within a model of a hybrid network on top of the Jsim simulation environment. Comparative tudies are made to show effective load balancing and crash tolerance in the presence of a high traffic overload.

  • 33.
    Delosières, Laurent
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    BATMAN Store-and-Forward: the Best of the Two Worlds2012In: Pervasive Computing and Communications Workshops (PERCOM Workshops), IEEE , 2012, p. 721-727Conference paper (Refereed)
    Abstract [en]

    The need for communication is highest in disaster scenarios when the infrastructure is also adversely affected. A recent protocol for ad hoc communication, the BATMAN protocol, is dependent on minimal infrastructure, in the form of mesh nodes that are used as access points, or nodes acting as an intermediary in a multi-hop connection. While BATMAN works well in a scenario in which there is a multihop path from senders to receivers at all times, it will drop the packets in intermittently-connected networks. Moreover, although implementation on a device is essential as a proof of concept, performing large scale evaluations requires a simulation platform in which variations in the operating environment can be studied. This paper is about adding the store-and-forward mechanism to the routing component in BATMAN nodes, to overcome intermittent connectivity through mobility. We describe an extension of the protocol, SF-BATMAN, that has been implemented in an interoperable manner with BATMAN, i.e. with no added signaling, and no change of basic BATMAN settings. We have implemented SF-BATMAN in a packet level simulator (NS3), and demonstrated its performance in a scenario that consists of two regions of connectivity: a wellconnected mesh network and a set of sparser subnetworks. We show that the added capability enhances the performance of BATMAN, through an increase of the delivery ratio by 20% with a lower overhead, while it exhibits a similar latency in comparable network scenarios.

  • 34.
    Elmquist, Jonas
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Formal Support for Quantitative Analysis of Residual Risks in Safety-Critical Systems2008In: High Assurance Systems Engineering Symposium, HASE 2008, IEEE Computer Society, 2008, p. 154-164Conference paper (Refereed)
    Abstract [en]

    With the increasing complexity in software and electronics in safety-critical systems new challenges to lower the costs and decrease time-to-market, while preserving high assurance have emerged. During the safety assessment process, the goal is to minimize the risk and particular, the impact of probable faults on system level safety. Every potential fault must be identified and analysed in order to determine which faults that are most important to focus on. In this paper, we extend our earlier work on formal qualitative analysis with a quantitative analysis of fault tolerance. Our analysis is based on design models of the system under construction. It further builds on formal models of faults that have been extended for estimated occurence probability allowing to analyse the system-level failure probability. This is done with the help of the probabilistic model checker PRISM. The extension provides an improvement in the costly process of certification in which all forseen faults have to be evaluated with respect to their impact on safety and reliability. We demonstrate our approach using an application from the avionic industry: an Altitude Meter System.

  • 35.
    Elmquist, Jonas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Intents and Upgrades in Component-Based High-Assurance Systems2005In: Model Driven Software Development / [ed] Sami Beydeda, Matthias Book, Volker Gruhn, Berlin, Heidelberg: Springer Verlag , 2005, p. 289-303Chapter in book (Other academic)
    Abstract [en]

    Abstraction is the most basic principle of software engineering. Abstractions are provided by models. Modeling and model transformation constitute the core of model-driven development. Models can be refined and finally be transformed into a technical implementation, i.e., a software system.

    The aim of this book is to give an overview of the state of the art in model-driven software development. Achievements are considered from a conceptual point of view in the first part, while the second part describes technical advances and infrastructures. Finally, the third part summarizes experiences gained in actual projects employing model-driven development.

    Beydeda, Book and Gruhn put together the results from leading researchers in this area, both from industry and academia. The result is a collection of papers which gives both researchers and graduate students a comprehensive overview of current research issues and industrial forefront practice, as promoted by OMG’s MDA initiative.

  • 36.
    Elmquist, Jonas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Intents, Upgrades and Assurance in Model-Based Development2004In: RTAS Workshop on Model-Driven Embedded Systems MoDES04,2004, 2004Conference paper (Refereed)
  • 37.
    Elmquist, Jonas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Safety-Oriented Design of Component Assemblies using Safety Interfaces2006In: Third International Workshop on Formal Aspects of Component Software FACS06,2006, 2006Conference paper (Refereed)
  • 38.
    Elmquist, Jonas
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Tool Support for Incremental Failure Mode and Effects Analysis of Component-Based Systems2008In: Design, Automation and Test in Europe, 2008. DATE '08, IEEE Computer Society, 2008, p. 921-927Conference paper (Refereed)
    Abstract [en]

    Failure mode and effects analysis (FMEA) is a well-known technique widely used for safety assessment in the area of safety-critical systems. However, FMEA is traditionally done manually which makes it both time-consuming and costly, specially for large and complex systems. Also, small modifications in the design may result in a complete revision of the initial FMEA. This paper presents a tool support for automated incremental component-based FMEA of SW and HW. It is based on component safety interfaces and a formal compositional safety analysis method. This tool support enables engineers to focus on more important steps in the safety assessment process. Also, during system upgrades, the tool incrementally registers the changes and identifies possible effects in the FMEA which enables the use of earlier safety analysis results. Finally, this formal approach based on design models of the components and the system always creates FMEAs which are consistent with the system design.

  • 39.
    Elmquist, Jonas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Minea, Marius
    Politehnica University of Timisoara.
    Safety Interfaces for Component-Based Systems2005In: Computer Safety, Reliability and Security,2005, Berlin, Heidelberg: Springer , 2005, p. 246-Conference paper (Refereed)
  • 40. Elmqvist, J.
    et al.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Safety-Oriented Design of Component Assemblies using Safety Interfaces2007In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 182, no SPEC. ISS., p. 57-72Article in journal (Refereed)
    Abstract [en]

    This paper promotes compositional reasoning in the context of safety-critical systems, and demonstrates a safety-oriented component model using an application from the automotive industry: an Adaptive Cruise Controller (ACC). The application consists of four components for which a set of 18 fault modes have been identified. We show the impact of all single faults and double faults selected from this set, on a safety property associated with the ACC assembly. Analysis related to each fault mode is performed using compositional rules and derived safety interfaces for each component. The derivation of safety interfaces for the ACC components has been supported by implementation of two extensions to the SCADE tool set: (1) a front end that iteratively and automatically builds the environment in which the component is resilient in presence of a given fault, (2) fault mode libraries that can be reused for modeling several classes of faults affecting the input of a component. The result of the study is the illustration of system level safety in presence of certain single and double faults, based on compositional reasoning and the automatically generated interfaces. The component model uses reactive modules as the formal notation. The instantiation of the model in terms of modules specified in SCADE provides a link between formal analysis of components in safety-critical systems and the traditional engineering processes supported by model-based development. © 2007 Elsevier B.V. All rights reserved.

  • 41.
    Elmqvist, Jonas
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Forsberg, Kristina
    Saab Avitronics, Jönköping.
    Nordenbro, Stellan
    Saab Avitronics, Jönköping.
    Demonstration of a Formal Method for Incremental Qualification of IMA Systems2008Conference paper (Refereed)
    Abstract [en]

    In this paper we address the process ofincremental certification/qualification of IntegratedModular Avionic (IMA) systems. The work aims toshow that given a scalable avionics architecture wecan apply a component-based development processand save some safety analysis effort by reusingdesign models for components. This creates aformal framework for IMA system safetyassessment.

  • 42.
    Forsberg, Kristina
    et al.
    Saab.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Torin, Jan
    Datateknik Chalmers Tekniska Högskola.
    Fault Analysis of a Distributed Flight Control System2005In: Fault-Tolerant and Dependable Distributed Systems Minitrack of the Software Technology Track, IEEE Hawaii International Conference on System Sciences,2005, Los Alamitos, CA, USA: IEEE Computer Society , 2005, p. 290-Conference paper (Refereed)
  • 43.
    Forsberg, Kristina
    et al.
    Airborne Equipment Division SaabTech.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Torin, Jan
    Department of Computer Engineering Chalmers university of Technology.
    Johansson, Rickard
    Saab Aerospace.
    Maintaining Consistency among Distributed Control Nodes2004In: IEEE Digital Avionics Systems Conference,2004, IEEE , 2004Conference paper (Refereed)
  • 44.
    Gamez, David
    et al.
    Department of Electronic Engineering Queen Mary University of London.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Bigham, John
    Department of Electronic Engineering Queen Mary University of London.
    Balducelli, C.
    ENEA C.R. Casaccia.
    Chyssler, Tobias
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Burbeck, Kalle Ring
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Safeguarding Critical Infrastructures2004In: Dependable Computing Systems: Paradigms, Performance Issues and Applications / [ed] Hassan B. Diab, Albert Y. Zomaya, Wiley Sons , 2004, p. -500Chapter in book (Other academic)
    Abstract [en]

    A team of recognized experts leads the way to dependable computing systems. With computers and networks pervading every aspect of daily life, there is an ever growing demand for dependability. In this unique resource, researchers and organizations will find the tools needed to identify and engage state of the art approaches used for the specification, design, and assessment of dependable computer systems. The first part of the book addresses models and paradigms of dependable computing, and the second part deals with enabling technologies and applications. Tough issues in creating dependable computing systems are also tackled, including: verification techniques, model based evaluation, adjudication and data fusion, robust communications primitives, fault tolerance, middleware, grid security, dependability in IBM mainframes, embedded software, and, real time systems. Each chapter of this contributed work has been authored by a recognized expert.This is an excellent textbook for graduate and advanced undergraduate students in electrical engineering, computer engineering, and computer science, as well as a must have reference that will help engineers, programmers, and technologists develop systems that are secure and reliable.

  • 45.
    Goldszmidt, Moises
    et al.
    Mirosoft Corporation, USA.
    Malek, Miroslaw
    Humboldt-Universität zu Berlin.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Narasimhan, Priya
    Carnegie Mellon University, USA.
    Salfner, Felix
    Humboldt-Universität zu Berlin.
    A. S. Ward, Paul
    University of Waterloo, Canada.
    Wilkes, John
    Google Inc., USA.
    Towards a Holistic Approach to Fault Management: Wheels Within a Wheel2011In: Dependability and Computer Engineering: Concepts for Software-Intensive Systems / [ed] Luigia Petre, Kaisa Sere and Elena Troubitsyna, IGI Global , 2011, p. 1-10Chapter in book (Refereed)
    Abstract [en]

    Systems with high dependability requirements are increasingly relying on complex on-line fault managementsystems. Such fault management systems involve a combination of multiple steps – monitoring,data analysis, planning and execution – that are typically independently developed and optimized.We argue that it is inefficient and ineffective to improve any particular fault management step withouttaking into account its interactions and dependencies with the rest of the steps. Through six real-lifeexamples, we demonstrate this inefficiency and how it results in systems that either under-perform orare over-budget. We propose a holistic approach to fault management that is aware of all relevant aspects,and explicitly considers the couplings between the different fault management steps. We believeit will produce systems that will better meet cost, performance and dependability objectives.

  • 46.
    Gürgens, Sigrid
    et al.
    Fraunhofer SIT, Darmstadt, Germany.
    Rudolph, Carsten
    Fraunhofer SIT, Darmstadt, Germany.
    Maña, Antonio
    University Malaga, Spain .
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Security engineering for embedded systems – the SecFutur vision2010Conference paper (Refereed)
  • 47.
    Hammarberg, Jerker
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Development of Safety-Critical reconfigurable Hardware with Esterel2003In: International Workshop on Formal Methods for Industrial Critical Systems FMICS,2003, 2003Conference paper (Refereed)
  • 48.
    Hammarberg, Jerker
    et al.
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    Development of Safety-Critical Reconfigurable Hardware with Esterel2003In: Proceedings of the 8th Internation Workshop on Formal Methods for Industrial Critical Systems (FMICS'03), Elsevier Publishers , 2003Conference paper (Refereed)
  • 49.
    Hammarberg, Jerker
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Development of safety-critical reconfigurable hardware with esterel2003In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 80, p. 229-244Conference paper (Other academic)
    Abstract [en]

    Demands for higher flexibility in aerospace applications has led to increasing deployment of FPGAs. Clearly, analysis of safety-related properties of such components is essential for their use in safety-critical subsystems. The contributions of this paper are twofold. First, we illustrate a development process, using a language with formal semantics (Esterel) for design, formal verification of high-level design and automatic code generation down to VHDL. We argue that this process reduces the likelihood of systematic (permanent) faults in the design, and still produces VHDL code that is of acceptable quality (size of FPGA, delay). Secondly, we show how the design model can be modularly extended with fault models that represent random faults (e.g. radiation) leading to bit flips in the component under design (resembling FMEA), and transient or permanent faults in the rest of the environment (corrupting inputs to the component or jeopardising the effect of output signals that control the environment). The set-up is then used to formally determine which (single or multiple) fault modes cause violation of the top-level safety-related property, much in the spirit of fault-tree analyses. An aerospace hydraulic monitoring system is used to illustrate the results. © 2003 Published by Elsevier Science B.V.

  • 50.
    Hammarberg, Jerker
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Nadjm-Tehrani, Simin
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory.
    Formal verification of fault tolerance in safety-critical reconfigurable modules2005In: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1385-4879, E-ISSN 1571-8115, Vol. 7, no 3, p. 268-279Article in journal (Refereed)
    Abstract [en]

    Demands for higher flexibility in aerospace applications has led to increasing deployment of reconfiguarble modules. In several cases the industry is looking into Field Programmable Gate Arrays (FPGA) as a means of efficient adaption of existing components. This paper addresses the safety analysis issues for reconfigurable modules with an emphasis on FPGAs. FPGAs act as digital hardware but in the context of safety analysis they should be treated as software, i.e. with added demands on formal analysis. The contributions of this paper are twofold. First, we illustrate a development process using a language with formal semantics (Esterel) for design, formal verification of high-level design, and automatic code generation down to synthesizable VHDL. We argue that this process reduces the likelihood of systematic (permanent) faults in the design, and still produces VHDL code that may be of acceptable quality (size of FPGA, delay). Secondly, in a general approach that is equally applicable to other formal design languages, we illustrate how the effect of transient fault modes and faults in external modules can be formally studied. We modularly extended the component design model with fault models that represent specific or random faults (e.g. radiation leading to bit flips in the component under design), and transient or permanent faults in the rest of the environment. Some faults corrupt inputs to the component and others jeopardise the effect of output signals that control the environment. This process supports a formal version of Failure Modes and Effects Analysis (FMEA). The set-up is then used to formally determine which (single or multiple) fault modes cause violation of the top-level safety-related property, much in the spirit of fault-tree analyses (FTA). All of this is done with out building the fault tree and using a common model for design and for safety analyses. An aerospace hydraulic monitoring system is used to illustrate the analysis of fault tolerance. © Springer-Verlag 2004.

123 1 - 50 of 110
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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