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  • 1.
    Delsing, Jerker
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eliasson, Jens
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Latency and packet loss of an interferred 802.15.4 channel in an industrial environment2010In: Fourth International Conference on Sensor Technologies and Applications, SENSORCOMM, International Academy, Research and Industry Association (IARIA), 2010, p. 33-38Conference paper (Refereed)
    Abstract [en]

    There is currently a rapid development of new types of wireless communication channels for industrial automation. This paper aims to provide some experimental data and theoretical justification on packet latency and packet loss for a wireless communication channel exposed to intentional radio interference. The intentional radio interference used in the experiments is an attempt to simulate possible future co-existence scenarios in a dense wireless communication environment at an industrial site. For the cases tested packet loses of less than 10% was obtained. Latency is shown to depend on channel access and will has a deterministic behaviour.

  • 2.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    A time constrained real-time process calculus2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    There are two important questions to ask regarding the correct execution of a real-time program: (i) Is there a platform such that the program executes correctly? (ii) Does the program execute correctly on a particular platform? The execution of a program is correct if all actions are taken within their execution window, i.e. after their release time but before their deadline. A program which executes correctly on a specific platform is said to be feasible on that platform and an incorrect program is one which is not feasible on any platform. In this thesis we develop a timed process calculus, based on the pi-calculus, which can help answer these questions. We express the time window in which computation is legal by use of two time restrictions, before and after, to express a deadline and a release time offset respectively. We choose to look at correctness through the traces of the program. The trace of a program will always be a sequence of interleaved internal reductions and time steps, because programs have no free names. We define the meaning of a feasible program by use of these traces. In particular we define the speed of a particular system as the ratio between work steps and time steps. Based on this calculus we show how the two questions above can be answered in terms of traces of the process calculus and prove the classical utilization limit for Earliest Deadline First scheduling holds.

  • 3.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    FIFO networking: punctual event-triggered networking2009In: 2009 IEEE Conference on Emerging Technologies & Factory Automation: ETFA 2009 ; Palma de Mallorca, Spain, 22 - 25 September 2009, Piscataway, NJ: IEEE Communications Society, 2009Conference paper (Refereed)
    Abstract [en]

    It is desirable to be able to combine ease of implementation of a network with the ability to analyze the properties of the network. In order to address this we present a MAC protocol where the network acts as a FIFO, and examine the resulting properties of the network using both a theoretical study of the waiting times and a simulation experiment. It turns out that this type of protocol would allows us to achieve real-time guarantees for an event-triggered system, as well as controlled jitter for message delivery. Further, temporal composability, and how to design a system using FIFO networking, is discussed.

  • 4.
    Leijon, Viktor
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    FIFO WiDOM: timely control over wireless links2007In: Proceedings of the 2007 IEEE Conference on Control Applications: Singapore, 1 - 3 October 2007 ; [part of IEEE Multi-Conference on Systems and Control, MSC], Piscataway, NJ: IEEE Communications Society, 2007, p. 1024-1030Conference paper (Refereed)
    Abstract [en]

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

  • 5.
    Leijon, Viktor
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wallin, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Ehnmark, Johan
    Data Ductus.
    SALmon: a Service Modeling Language and Monitoring Engine2008In: IEEE International Symposium on Service-Oriented System Engineering: SOSE '08 / [ed] Jonathan Lee; Deron Liang; Y.C. Cheng, Los Alamitos, Calif: IEEE Communications Society, 2008, p. 202-207Conference paper (Refereed)
    Abstract [en]

    To be able to monitor complex services and examine their properties we need a modeling language that can express them in an efficient manner. As telecom operators deploy and sell increasingly complex services the need to monitor these services increases. We propose a novel domain specific language called SALmon, which allows for efficient representation of service models, together with a computational engine for evaluation of service models. This working prototype allows us to perform  experiments with full scale service models, and proves to be a good trade-off between simplicity and expressive power.

  • 6.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Multipurpose models for QoS monitoring2007In: 21st International Conference on Advanced Information Networking and Applications Workshops: Niagara Falls, Ontario, Canada, 21 - 23 May 2007 ; proceedings, Los Alamitos, Calif: IEEE Communications Society, 2007, Vol. 1, p. 900-905Conference paper (Refereed)
    Abstract [en]

    Telecom operators face an increasing need for service quality management to cope with competition and complex service portfolios in the mobile sector. Improvements in this area can lead to significant market benefits for operators in highly competitive markets. We propose an architecture for a service monitoring tool, including a time aware formal language for model specification. Using these models allows for increased predictability and flexibility in a constantly changing environment.

  • 7.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Rethinking network management solutions2006In: IT Professional Magazine, ISSN 1520-9202, E-ISSN 1941-045X, Vol. 8, no 6, p. 19-23Article in journal (Refereed)
    Abstract [en]

    Telecommunication network management solutions need to shift perspective from one of network element management to service management. Operators need a service view of their network, with automatic service-impact correlation. This requires some major changes in the underlying solutions: equipment vendors must improve the supplied management interfaces and network management solutions must implement a higher degree of automation and correlation with a service focus. One obstacle is the lack of models and formalism to describe topology and service structures

  • 8.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Telecom network and service management: an operator survey2009In: Wired-Wireless Multimedia Networks and Services Management: 12th IFIP/IEEE International Conference on Management of Multimedia and Mobile Networks and Services, MMNS 2009, Venice, Italy, October 26-27, 2009. Proceedings / [ed] Tom Pfeifer; Paolo Bellavista, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2009, p. 15-26Conference paper (Refereed)
    Abstract [en]

    It is hard to know which research problems in network management we should focus our attention on. To remedy this situation we have surveyed fifteen different telecom operators on four continents to gather some feedback on what they desire and expect from the network management research community. Their input forms a foundation for future directions in network management research, and provides us with valuable insight into what the most urgent problems are in industry.

  • 9.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science. Data Ductus Nord AB, Skellefteå, Sweden.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Landén, Leif
    Data Ductus Nord AB, Skellefteå, Sweden.
    Statistical analysis and prioritisation of alarms in mobile networks2009In: International Journal of Business Intelligence and Data Mining, ISSN 1743-8195, Vol. 4, no 1, p. 4-21Article in journal (Refereed)
    Abstract [en]

    Telecom Service Providers are faced with an overwhelming flow of alarms, which makes good alarm classification and prioritization very important. This paper first provides statistical analysis of data collected from a real-world alarm flow and then presents a quantitative characterization of the alarm situation. Using data from the trouble ticketing system as a reference, we examine the relationship between mechanical classification of alarms and the human perception of them.Using this knowledge of alarm flow properties and trouble ticketing information, we suggest a neural network-based approach for alarm classification. Tests using live data show that our prototype assigns the same severity as a human expert in 50% of all cases, compared to 17% for a naive approach.

  • 10. Wallin, Stefan
    et al.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Nordlander, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Bystedt, Niklas
    Yalt.
    The semantics of alarm definitions: enabling systematic reasoning about alarms2012In: International Journal of Network Management, ISSN 1055-7148, E-ISSN 1099-1190, Vol. 22, no 3, p. 181-198Article in journal (Refereed)
    Abstract [en]

    The development and integration of an alarm interface between network elements and a network management system is a costly process, largely because of the informal way in which alarm interfaces are expressed and communicated. Low-quality alarm documentation and confusion around fundamental concepts like alarm states and alarm types are typical consequences of current practices. If alarm interfaces were expressed in a more formal manner, costs could be reduced and more advanced analysis and automation would be enabled. We present a novel approach to alarm interfaces by providing a formal alarm model together with a domain-specific language that allows us to specify both the alarm models and the constraints placed on the alarm models in a consistent manner. This means that we can verify the consistency of an alarm interface and automatically generate artifacts such as alarm correlation rules or alarm documentation based only on the model

  • 11.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Nordlander, Johan
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Semantic Alarms2014In: 3rd ETSI Future Networks Workshop, 9-11 april 2013, Sophia Antipolis, France / [ed] Alex Galis; Gaby Lenhart, 2014, p. 145-153Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Functions Virtualisation (NFV) and Software Driven Networks (SDN) aggregate resources across multiple domains. This puts requirements on understanding the overall alarm status across these domains and dependencies between them. Current practice of low-quality alarm documentation and confusion around fundamental concepts like alarm states, alarm-types and the underlying protocols like syslog and SNMP traps makes it hard to create one unified alarm interface as part of the SDN API.If alarm interfaces for the various components were expressed in a more formal manner including dependencies and propagation between the alarms the NFV/SDN interface could automatically present an integrated alarm API as well as a synthesized alarm state across the virtualized functions.We present a novel approach to alarm interfaces by providing a formal alarm model together with a domain-specific language that allows us to specify both the alarm models and the constraints placed on the alarm models in a consistent manner. This means that we can verify the consistency of an alarm interfaces and automatically generate interfaces, multi-domain correlation and aggregated states.

1 - 11 of 11
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  • ieee
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