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  • 1.
    Abdollahi, Kamran
    et al.
    Computer and Science Department Iran University of Science and Technology Tehran, Iran.
    Shams Shafigh, Alireza
    Computer and Science Department Iran University of Science and Technology Tehran, Iran.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Improving Performance of On Demand Multicast Routing by deleting lost join query packet2010In: Proceedings of The Sixth Advanced International Conference on Telecommunications - AICT 2010, IEEE conference proceedings, 2010, 316-322 p.Conference paper (Refereed)
    Abstract [en]

    A Mobile ad hoc network is a collection of wireless nodes that dynamically organize themselves to form a network without the need for any fixed infrastructure or centralized administration. The network topology dynamically changes frequently in an unpredictable manner since nodes are free to move. Support for multicasting is essential in such environment as it is considered to be an efficient way to deliver information from source nodes to many client nodes. A problem with multicast routing algorithms is their efficiency as their forwarding structure determines the overall network resource consumption makes them significantly less efficient than unicast routing algorithms. In this research, we improve the performance of the popular ODMRP multicast routing protocol by restricting the domain of join query packets, which have been lost. This is achieved by augmenting the join query packets with minimum extra information (one field), which denotes the number of the visited node from previous forwarding group. Simulation results show, that our mechanisms significantly reduce the control traffic and thus the overall latency and power consumption in the network.

  • 2.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Partial Signature Matching in an MPTCP World using Insert-only Levenshtein DistanceManuscript (preprint) (Other academic)
    Abstract [en]

    This paper proposes a methodology consisting of a constrained version of the Levenshtein distance that can be used to detect signatures from partial traffic. The proposed algorithm is formally presented, implemented, and tested using the latest available version of the Snort ruleset. The results show that the algorithm can successfully detect all partial signatures with nearly 90% accuracy.

  • 3.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Multipath TCP IDS Evasion and Mitigation2015In: Information Security: 18th International Conference, ISC 2015, Trondheim, Norway, September 9-11, 2015, Proceedings, Springer, 2015, Vol. 9290, 265-282 p.Conference paper (Refereed)
    Abstract [en]

    The existing network security infrastructure is not ready for future protocols such as Multipath TCP (MPTCP). The outcome is that middleboxes are configured to block such protocols. This paper studies the security risk that arises if future protocols are used over unaware infrastructures. In particular, the practicality and severity of cross-path fragmentation attacks utilizing MPTCP against the signature-matching capability of the Snort intrusion detection system (IDS) is investigated. Results reveal that the attack is realistic and opens the possibility to evade any signature-based IDS. To mitigate the attack, a solution is also proposed in the form of the MPTCP Linker tool. The work outlines the importance of MPTCP support in future network security middleboxes.

  • 4.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Lidén, Anders
    Towards Multipath TCP Aware Security Technologies2016In: New Technologies, Mobility and Security (NTMS), 2016 8th IFIP International Conference on, IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    Multipath TCP (MPTCP) is a proposed extension to TCP that enables a number of performance advantages that have not been offered before. While the protocol specification is close to being finalized, there still remain some unaddressed challenges regarding the deployment and security implications of the protocol. This work attempts to tackle some of these concerns by proposing and implementing MPTCP aware security services and deploying them inside a proof of concept MPTCP proxy. The aim is to enable hosts, even those without native MPTCP support, to securely benefit from the MPTCP performance advantages. Our evaluations show that the security services that are implemented enable proper intrusion detection and prevention to thwart potential attacks as well as threshold rules to prevent denial of service (DoS) attacks.

  • 5.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Lidén, Anders
    A Multipath TCP Proxy2015Conference paper (Refereed)
    Abstract [en]

    Multipath TCP (MPTCP) is an extension to traditionalTCP that enables a number of performance advantages,which were not offered before. While the protocol specificationis close to being finalized, there still remain some concernsregarding deployability and security. This paper describes theon going work to develop a solution that will facilitate thedeployment of MPTCP. The solution will not only allow non-MPTCP capable end-hosts to benefit from MPTCP performancegains, but also help ease the network security concerns that manymiddleboxes face due to the possibility of data stream beingfragmented across multiple subflows.

  • 6. Agustí, Ramón
    et al.
    Fazekas, Péter
    Gómez Barquero, David
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Oliver, Miquel
    Pérez-Romero, Jordi
    Tralli, Velio
    NEWCOM DR7.2: First report on common framework/models and activities in Department 72005Report (Refereed)
    Abstract [en]

    This deliverable provides a description of the framework identified for the collaborative activities between different partners in the context of NEWCOM department 7 on QoS provision in heterogeneous wireless networks. The considered models, assumptions and expected results are pointed out for each activity. The deliverable also includes a report on the means to achieve the integration between the different partners

  • 7. Agustí, Ramón
    et al.
    Fazekas, Péter
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Oliver, Miquel
    Pérez-Romero, Jordi
    Studer Ferreira, Lucio
    Tralli, Velio
    NEWCOM DR7.4: Final Report on the activities carried out in Department 72007Report (Refereed)
    Abstract [en]

    This deliverable constitutes the final report of all the activities that carried out in the framework of the NEWCOM department 7. It contains a description of the main technical achievements for each one of the activities in which the department has been organised togehter with the list of indicators reflecting the degree of integration that has been achieved among the different partners

  • 8.
    Ahlgren, Bengt
    et al.
    RISE SICS.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Abrahamsson, Henrik
    RISE SICS.
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Are MIRCC and Rate-based Congestion Control in ICN READY for Variable Link Capacity?2017In: The 13th Swedish National Computer Networking Workshop (SNCNW 2017), Halmstad University, May 29.30., 2017Conference paper (Other academic)
    Abstract [en]

    Information-centric networking (ICN) has been introduced as a potential future networking architecture. ICN promises an architecture that makes information independent from lo- cation, application, storage, and transportation. Still, it is not without challenges. Notably, there are several outstanding issues regarding congestion control: Since ICN is more or less oblivious to the location of information, it opens up for a single application flow to have several sources, something which blurs the notion of transport flows, and makes it very difficult to employ traditional end-to-end congestion control schemes in these networks. Instead, ICN networks often make use of hop-by-hop congestion control schemes. How- ever, these schemes are also tainted with problems, e.g., several of the proposed ICN congestion controls assume fixed link capacities that are known beforehand. Since this seldom is the case, this paper evaluates the consequences in terms of latency, throughput, and link usage, variable link capacities have on a hop-by-hop congestion control scheme, such as the one employed by the Multipath-aware ICN Rate-based Congestion Control (MIRCC). The evaluation was carried out in the OMNeT++ simulator, and demonstrates how seemingly small variations in link capacity significantly deterio- rate both latency and throughput, and often result in inefficient network link usage. 

  • 9. Aitenbichler, Erwin
    et al.
    Behring, Alexander
    Bradler, Dirk
    Hartmann, Melanie
    Martucci, Leonardo
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Mühlhäuser, Max
    Ries, Sebastian
    Schnelle-Walka, Dirk
    Schreiber, Daniel
    Steimle, Jürgen
    Strufe, Thorsten
    Shaping the Future Internet2009In: Shaping the Future Internet, 2009Conference paper (Refereed)
    Abstract [en]

    The Internet of Things (IoT) and the Internet of Services (IoS) are two well-knownexemplars of the emerging ‘Internet variants’. These variants will be tightlyinterwoven yet specific with respect to the supporting technologies needed. Thepresent paper discusses the five variants identified as essential by the authors: IoT,IoS, Internet-of-Humans, Internet-of-Crowds, and Internet-of-Clouds. For eachvariant, a non-comprehensive set of research challenges is cited and related to thestate of the art and to ongoing projects of the lab.

  • 10.
    Alfredsson, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    A Cross-Layer Perspective on Transport Protocol Performance in Wireless Networks2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Communication by wireless technologies has seen a tremendous growth in the last decades. Mobile phone technology and wireless broadband solutions are rapidly replacing the last-hop wireline connectivity for telephones and Internet access.  Research has, however, shown that Internet traffic can experience a performance degradation over wireless compared to wired networks.  The inherent properties of radio communication lead to a higher degree of unreliability, compared to communication by wire or fiber.  This can result in an increased amount of transmission errors, packet loss, delay and delay variations, which in turn affect the performance of the main Internet transport protocols TCP and UDP.  This dissertation examines the cross-layer relationship between wireless transmission and the resulting performance on the transport layer. To this end, experimental evaluations of TCP and UDP over a wireless 4G downlink system proposal are performed.  The experiment results show, in a holistic scenario, that link-level adaptive modulation, channel prediction, fast persistent link retransmissions, and channel scheduling, enables the transport protocols TCP and UDP to perform well and utilize the wireless link efficiently.  Further, a novel approach is proposed where a modified TCP receiver can choose to accept packets that are corrupted by bit errors. Results from network emulation experiments indicate that by accepting and acknowledging even small amounts of corrupted data, a much higher throughput can be maintained compared to standard TCP.

  • 11.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Division for Information Technology.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Division for Information Technology.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    A 4G Link Level Emulator for Transport Protocol Evaluation2004In: Proceedings of The Second Swedish National Computer Networking Workshop (SNCNW), 2004, 19-23 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a wireless link and networkemulator, based upon the "Wireless IP" 4G system proposalfrom Uppsala University and partners. In wireless fading down-links (base to terminals) link-level frames are scheduled andthe transmission is adapted on a fast time scale. With fastlink adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteractedat the physical and link layers. A purpose of the emulatoris to investigate the resulting interaction with transport layer protocols. The emulator is built on Internet technologies, andis installed as a gateway between communicating hosts. The paper gives an overview of the emulator design, and presentspreliminary experiments with three different TCP variants. The results illustrate the functionality of the emulator by showing theeffect of changing link layer parameters on the different TCP variants.

  • 12.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Cross-layer analysis of TCP performance in a 4G system2007In: Proceedings of the 15th International Conference on Software, Telecommunications and Computer Networks, IEEE Computer Society, 2007Conference paper (Refereed)
    Abstract [en]

    This paper presents results from an experimental study of TCP in a wireless 4G evaluation system. Test-bed results on transport layer performance are presented and analyzed in relation to several link layer aspects. The aspects investigated are the impact of channel prediction errors, channel scheduling, delay, and adaptive modulation switch level, on TCP performance. The paper contributes a cross-layer analysis of the interaction between symbol modulation levels, different scheduling strategies, channel prediction errors and the resulting frame retransmissions effect on TCP. The paper also shows that highly persistent ARQ with fast link retransmissions do not interact negatively with the TCP retransmission timer even for short round trip delays.

  • 13.
    Alfredsson, Stefan
    et al.
    Karlstad University, Division for Information Technology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Division for Information Technology.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Emulation and Validation of a 4G System Proposal2005In: Proceedings of RadioVetenskap och Kommunikation 2005: Volume II, 2005, 357-362 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a wireless link and network emulator,along with experiments and validation against the "Wireless IP" 4G system proposal from Uppsala University and partners. In wireless fading downlinks (base to terminals) link-level frames are scheduled and the transmission is adapted on a fast time scale. With fast link adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteracted at thephysical and link layers. The emulator has been used to experimentally investigate the resulting interaction between the transport layer and the link layer. The paper gives an overview of the emulator design, and presents experimental results with three different TCP variants in combination with various link layer characteristics.

  • 14.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Impact of 4G Wireless Link Configurations on VoIP Network Performance2008In: Proceedings of the 2008 IEEE International Symposium on Wireless Communication Systems, IEEE Communications Society, 2008, 708-712 p.Conference paper (Refereed)
    Abstract [en]

    The performance of applications in wireless networks is partly dependent upon the link configuration. Link characteristics varies with frame retransmission persistency, link frame retransmission delay, adaptive modulation strategies, coding, and more. The link configuration and channel conditions can lead to packet loss, delay and delay variations, which impact different applications in different ways. A bulk transfer application may tolerate delays to a large extent, while packet loss is undesirable. On the other hand, real-time interactive applications are sensitive to delay and delay variations, but may tolerate packet loss to a certain extent. This paper contributes a study of the effect of link frame retransmission persistency and delay on packet loss and latency for real-time interactive applications. The results indicate that a reliable retransmission mechanism with fast link retransmissions in the range of 2-8 ms is sufficient to provide an upper delay bound of 50 ms over the wireless link, which is well within the delay budget of voice over IP applications.

  • 15.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Transport Protocol Performance over 4G Links: Emulation Methodology and Results2006In: Proceedings of the International Symposium on Wireless Communication Systems (ISWCS), IEEE Computer Society, 2006, 327-332 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a wireless link and network emulator for the "Wireless IP" 4G system proposal from Uppsala University and partners. In wireless fading downlinks (base to terminals) link-level frames are scheduled and the transmission is adapted on a fast time scale. With fast link adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteracted at the physical and link layers. The emulator has been used to experimentally investigate the resulting interaction between the transport layer and the physical/link layer in such a downlink. The paper introduces the Wireless IP system, describes the emulator design and implementation, and presents experimental results with TCP in combination with various physical/link layer parameters. The impact of link layer ARQ persistency, adaptive modulation, prediction errors and simple scheduling are all considered.

  • 16. Ali Yahiya, Tara
    et al.
    Chaouchi, Hakima
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Pujolle, Guy
    Seamless Interworking of WLAN and WMAN Wireless Networks2006Conference paper (Refereed)
    Abstract [en]

    Future network environments will be heterogeneous and mobile terminals will have the opportunity to dynamically select among many different access technologies. Therefore, it is important to provide service continuity in case of vertical handovers when terminals change the access technology. Two important wireless access technologies are WLAN (Wireless Local Access Networks) and WMAN (Wireless Metropolitan Access Networks) networks. In this paper, we address several challenges related to a seamless integration of those technologies. We highlight important aspects for designing a WLAN/WMAN interworking architecture and we address important Quality of Service (QoS) issues for such interworked systems like degree of QoS support provided by the technologies, QoS mapping and signalling for vertical handover. By formulating several interworking scenarios, where WLAN users with ongoing voice, video and data sessions hand over to WMAN, we study QoS and performance issues and analyse feasibility of seamless session continuity through simulations

  • 17. Allman, Mark
    et al.
    Avrachenkov, Konstatin
    Ayesta, Urtzi
    Blanton, Josh
    Hurtig, Per
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Early Retransmit for TCP and SCTP2008Other (Other (popular science, discussion, etc.))
    Abstract [en]

    This document proposes a new mechanism for TCP and SCTP that can be used to recover lost segments when a connection's congestion window is small. The "Early Retransmit" mechanism allows the transport to reduce, in certain special circumstances, the number of duplicate acknowledgments required to trigger a fast retransmission. This allows the transport to use fast retransmit to recover packet losses that would otherwise require a lengthy retransmission timeout.

  • 18. Andersson, Carin
    et al.
    Lindskog, Stefan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Survey and Analysis of Project Management Competence within Research Projects at Karlstad University2007Other (Other (popular science, discussion, etc.))
    Abstract [en]

    Research at universities is today often conducted as projects. This is especially true in the engineering, natural science, medicine, and social science disciplines. Research projects are typically carried out by different categories of employers, such as professors, associate professors, assistant professors, and PhD students. These projects are typically managed by the person that applied for the project money, or the person that is the most experienced researcher at the department, which is often a professor or associate professor. From such leading persons, miracles are expected. Except acting as project managers, they are also engaged in many other parallel activities, e.g., supervision of PhD students, undergraduate and graduate education, conference organization and administration, project application writing, and representing the department internally as well as externally.



    In this report, a survey of project management competence within research projects at Karlstad University is presented. Empirical data have been gathered through two questionnaires and six complementary interviews. Professors and associate professors as well as PhD students have participated in the study. The survey shows that the active project managers have learned to lead projects based on experience and very few project managers have a formal leadership education. This implies that long established project management methods and tools are seldom used.



    Based on the outcome from the survey and our own observations, four concrete activities to improve project management skills are proposed in the report. The first activity is to provide a suitable and well-balanced course in project management methods that is offered to both active and future project managers. The second activity is to establish experience networks among active project mangers at Karlstad University. The third activity is to create a mentor program for new project managers. The fourth activity is to establish a group of experienced project managers that can assist in and give support to ongoing and planned projects.

  • 19. Andersson, Christer
    et al.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Enabling anonymity for the mobile Internet using the mCrowds system2004In: Risk and Challenges of the Network Society: Proceedings of the Second IFIP WG 9.2, 9.6/11.6, 11.7 International Summer School / [ed] Penny Duquenoy, Simone Fischer-Hübner, Jan Holvast, and Albin Zuccato, Karlstad University Press, 2004, 178-189 p.Chapter in book (Refereed)
    Abstract [en]

    The mobile Internet is a fast growing technology that introduces new privacy risks. We argue that, since privacy legislation alone is not sufficient to protect the users privacy, technical solutions to enhanceinformational privacy of individuals are also needed. This paper introduces mCrowds, a privacy-enhancing technology that combines the concept of a crowd system in a mobile Internet setting with a filteringfunctionality to enable anonymity towards the content providers

  • 20.
    Andersson, Christer
    et al.
    Karlstad University, Division for Information Technology.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lundin, Reine
    Karlstad University, Division for Information Technology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    mCrowds: Anonymity for the Mobile Internet2003In: HumanIT 2003, Karlstad: Karlstad University Press, 2003, 79-92 p.Chapter in book (Refereed)
  • 21. Andersson, Christer
    et al.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    On the Fundamentals of Anonymity Metrics2007In: The Future of Identity in the Information Society: Proceedings of the Third IFIP WG 9.2, 9.6/ 11.6, 11.7/FIDIS International Summer School on The Future of Identity in the Information Society / [ed] Simone Fischer-Hübner, Penny Duquenoy, Albin Zuccato and Leonardo Martucci, 2007Conference paper (Refereed)
  • 22.
    Andersson, Christer
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Martucci, Leonardo A.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Privacy & Anonymity in Mobile Ad Hoc Networks2008In: Handbook of Research on Wireless Security / [ed] Yan Zhang, Jun Zheng & Miao Ma, IGI Global , 2008Chapter in book (Other academic)
  • 23. Andersson, Christer
    et al.
    Martucci, Leonardo
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Privacy and Anonymity in Mobile Ad Hoc Networks2008In: Mobile Computing: Concepts, Methodologies, Tools, and Applications / [ed] David Taniar, Information Science Reference , 2008Chapter in book (Refereed)
  • 24. Andersson, Christer
    et al.
    Martucci, Leonardo
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Privacy Requirements for Mobile Ad Hoc Networks2005Conference paper (Refereed)
  • 25.
    Andersson, David
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Teoretisk och praktisk genomgång av IPv6 och dess säkerhetsaspekter2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This paper takes a theoretical as well as a practical approach to what IPv6 is in order to create an understanding for the new protocol. In addition to the theoretical review of the protocol, this paper also describes the work that has been done in order to create an implementation that is supposed to bring  secure IPv6 support to both private individuals and smaller organizations, even if the Internet service provider only offers IPv4.

     

    This paper and implementation is done on a personal initiative, since the need for knowledge regarding IPv6 is rapidly increasing and private individuals probably will be among the last to be offered native IPv6 support from their Internet service providers.

  • 26.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    CASSCF second-order perturbation theory (CASPT2)1998In: Encyclopedia of Computational Chemistry / [ed] P. von Ragué Schleyer, Chichester, England: John Wiley & Sons , 1998Chapter in book (Refereed)
  • 27.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Cellular Automata2003Other (Other (popular science, discussion, etc.))
    Abstract [en]

    Properties and behavior of cellular automata are considered. Cellular automata can simply be described as lattices of cells, where the cells can be in a finite number of states. By using simple rules the states of the cells are updated at discrete time steps. The evolution of cellular automata can be used for computations. Some cellular automata display universality meaning that there is no limit to the sophistication of the computations they can perform.

  • 28.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Cellular Automata2004In: Promote IT 2004: proceedings of the fourth Conference for the Promotion of Research in IT at New Universities and University Colleges in Sweden : 5-7 May, 2004, Karlstad University, Sweden. P. 1 / [ed] Bubenko, Janis, Karlstad: Karlstad University Press , 2004, Vol. 2004:26, 598-608 p.Conference paper (Refereed)
    Abstract [en]

    In this paper properties and behavior of cellular automata are considered. Cellular automata can simply be described as lattices of cells, where the cells can be in a finite number of states. By using simple rules the states of the cells are updated in parallel at discrete time steps. Depending on the rule and, to a certain degree, the initial states of the cells, the evolution of a cellular automaton is restricted to a small number a ways. Some cellular automata evolve uniformly, meaning that all cells end up in the same state, while others evolve randomly, meaning that the states of the cells appear to be totally randomized during evolution. Intermediate behavior, displaying repetitiveness or nesting, also occurs.Properties of cellular automata that are discussed in the paper are, for instance, sensitivity to initial conditions, randomness, reversibility, entropy, and conservation. These properties also appear in the physical world and cellular automata provide good examples in the understanding of these properties.The evolution of cellular automata can be used for computations. Some cellular automata even display the property of universality, a term well known from the universal Turing machine, meaning that there is no limit to the sophistication of the computations they can perform.

  • 29.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Cellular Automata2005In: Promote IT 2005: proceedings of the fifth Conference for the Promotion of Research in IT at New Universities and University Colleges in Sweden : Borlänge, Sweden 11-13 May, 2005 / [ed] Bubenko, Janis, Lund: Studentlitteratur , 2005, 21-30 p.Conference paper (Refereed)
    Abstract [en]

    Cellular automata have a widespread use in the description of complex phenomena in disciplines as disparate as for example physics and economics. They are described by a lattice of cells, states of the cells, and rules for updating the states of the cells. One characteristics of a cellular automaton is the simplicity of the rules that determine how the cellular automaton evolves in time. These rules are local, are applied in parallel to all the cells and despite their simplicity they may give rise to a complex macroscopic behaviour. In this paper this is illustrated by examples from hydrodynamics and it is shown that cellular automata might provide powerful alternatives to partial differential equations

  • 30.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Cellular Automata in Science2005Other (Other (popular science, discussion, etc.))
    Abstract [en]

    Cellular automata have a widespread use in the description of complex phenomena in disciplines as disparate as, for example, physics and economics. A cellular automaton is a lattice of cells, and the cells can be in a finite number of states. By using simple local rules the states of the cells are updated in parallel at discrete time steps. In short, a cellular automaton can be characterised by the three words - simple, local, and parallel. These three words are one of the reasons for the attractiveness of cellular automata. They are simple to implement and they are well suited for parallel computers (computations). Another reason for using cellular automata are for their spatio-temporal properties. The lattice may represent space and the updating of the cells gives a

    dimension of time.



    In spite of the simplicity of cellular automata they may give rise to a complex macroscopic behaviour. This is illustrated, in this thesis, by an hydrodynamic example, namely the creation of vortices in flow behind a cylinder.



    Although cellular automata have the ability to describe complex phenomena it is sometimes hard to find the proper rules for a given macroscopic behaviour. One approach which has been successfully employed is to let cellular automata rules evolve (for example, through genetic algorithms) when finding the desired properties. In this thesis this is demonstrated for two-dimensional cellular automata with two possible states of the cells. A genetic algorithm is used to find rules that evolve a given initial configuration of the cells to another given configuration.

  • 31.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Different forms of the zeroth-order Hamiltonian in second-order perturbation theory with a complete active space self-consistent field reference function1995In: Theoretica Chimica Acta, 91:31Article in journal (Refereed)
  • 32.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Multiconfigurational perturbation theory1992Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The aim of the thesis is to analyze a method which describes the electron correlation in atoms and molecules. The method is based on Rayleigh-Schrödinger perturbation theory with a partitioning of the Hamiltonian into a fairly simple zeroth-order operator and a perturbation operator. The zeroth-order Hamiltonian is founded on a one-electron Fock-type operator and two different operators have been tested. The zeroth-order wave function is constructed from a complete active space self-consistent field (CASSCF) calculation. This means that the zeroth-order wave function for open-shell systems and systems with strong configurational mixing (near degeneracy) can be obtained on an equal level as closed-shell (single determinant) states. The theory is formulated in such a way that the Möller-Plesset perturbation theory is obtained for the closed-shell (single determinant) state. The flexibility of the CASSCF method makes it possible, in principle, to construct the zeroth-order wave function (and the zeroth-order Hamiltonian) to any desired accuracy. The perturbation expansion of the energy is therefore expected to converge fast and only up to the second-order contribution has been implemented leading to fairly fast and accurate calculations. The aim of the computer implementation is to describe the electron correlation in small and medium-sized molecules (up to 20 atoms) accurately. The application of the perturbation method to a number of problems in chemistry is demonstrated in the thesis: (1) the calculation of electronic properties and harmonic vibrational frequencies of the ozone molecule; (2) the calculation of electric dipole polarizabilities of excited valence states of several first- and second-row atoms; (3) the calculation of excited states of the nickel atom, the benzene molecule, and the azabenzenes pyridine, pyrazine, pyridazine, and s-triazine

  • 33.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Numerical Evaluation of the Average Number of Successive Guesses2012In: Unconventional Computation and Natural Computation: 11th International Conference, UCNC 2012, Orléans, France, September 3-7, 2012, Proceedings / [ed] Jérôme Durand-Lose, Natasa Jonoska, Berlin Heidelberg: Springer , 2012, 234-234 p.Conference paper (Refereed)
  • 34.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    The electronic spectrum of Cr21995In: Chemical Physics Letters, 237:212Article in journal (Refereed)
  • 35.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    The electronic spectrum of VCr2003In: Theoretical Chemistry Accounts, volume 110, number 3Article in journal (Refereed)
    Abstract [en]

    The electronic spectrum of VCr has been studied using the complete-active-space self-consistent field complete-active-space second-order perturbation theory approach. Potential energy curves for 12 electronic states have been computed. Transition energies, with respect to the X^2Delta ground state, for some of the calculated electronic states are (with possible experimental values within parentheses): 0.53 eV (0.56) for A^2Sigma+, 1.03 eV (1.14) for A^4Delta, 1.20 eV (1.14) for B^2Delta, 1.45 eV (1.51) for B^4Delta, 1.60 eV (1.51, 1.78) for C^2Delta, and 1.61 eV (1.63) for A^4Sigma^-.

  • 36.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Vad är det för kunskap som värderas?2000In: Universitetsläraren, nummer 7Article in journal (Other (popular science, discussion, etc.))
  • 37.
    Andersson, Kerstin
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Vad är kunskap?2006In: Kapet, nummer 1, Vol. 1Article in journal (Other (popular science, discussion, etc.))
  • 38.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Bauschlicher Jr., C. W.
    Persson, B. J.
    Roos, B. O.
    The structure of dichromium tetraformate1996In: Chemical Physics Letters, 257:238Article in journal (Refereed)
  • 39.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Borowski, P.
    Fowler, P. W.
    Malmqvist, P.-Å.
    Roos, B. O.
    Sadlej, A. J.
    Electric properties of the ozone molecule1992In: Chemical Physics Letters, 190:367Article in journal (Refereed)
  • 40.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Fulscher, M. P.
    Lindh, R.
    Malmqvist, P.-Å.
    Olsen, J.
    Roos, B. O.
    Widmark, P.-O.
    MOLCAS: A general purpose quantum chemistry program system for correlated wavefunctions1994In: Methods and Techniques in Computational Chemistry: METECC-94, chapter 7, page 275 / [ed] Enrico Clementi, Cagliari, Italy: STEF , 1994Chapter in book (Refereed)
  • 41.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Malmqvist, P.-Å.
    Roos, B. O.
    Second-order perturbation theory with a complete active space self-consistent field reference function1992In: Journal of Chemical Physics, 96:1218Article in journal (Refereed)
  • 42.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Malmqvist, P.-Å.
    Roos, B. O.
    Sadlej, A. J.
    Wolinski, K.
    Second-order perturbation theory with a CASSCF reference function1990In: Journal of Physical Chemistry, 94:5483Article in journal (Refereed)
  • 43.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Roos, B. O.
    Excitation energies in the nickel atom studied with the complete active space SCF method and second-order perturbation theory1992In: Chemical Physics Letters, 191:507Article in journal (Refereed)
  • 44.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Roos, B. O.
    Multiconfigurational second-order perturbation theory1995In: Modern electronic structure theory, volume 1 / [ed] D. R. Yarkony, New York: World Scientific Publishing , 1995Chapter in book (Refereed)
  • 45.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Roos, B. O.
    Multiconfigurational second-order perturbation theory: A test of geometries and binding energies1993In: International Journal of Quantum Chemistry, 45:591Article in journal (Refereed)
  • 46.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Roos, B. O.
    Malmqvist, P.-Å.
    Widmark, P.-O.
    The Cr2 potential energy curve studied with multiconfigurational second-order perturbation theory1994In: Chemical Physics Letters, 230:391Article in journal (Refereed)
  • 47.
    Andersson, Kerstin
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Sadlej, A. J.
    Electric dipole polarizabilities of atomic valence states1992In: Physical Review A, 46:2356Article in journal (Refereed)
  • 48.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Pulls, Tobias
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Ulrich, König
    HCI for Policy Display and Administration2011In: Privacy and Identity Management for Life / [ed] Jan Camenish, Simone Fischer-Hübner and Kai Rannenberg, Berlin: Springer Berlin/Heidelberg, 2011, 1, 261-277 p.Chapter in book (Refereed)
    Abstract [en]

    The PrimeLife Policy Language (PPL) has the objective of helping end users make the data handling practices of data controllers more transparent, allowing them to make well-informed decisions about the release of personal data in exchange for services. In this chapter, we present our work on user interfaces for the PPL policy engine, which aims at displaying the core elements of a data controller's privacy policy in an easily understandable way as well as displaying how far it corresponds with the user's privacy preferences. We also show how privacy preference management can be simplified for end users.

  • 49.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Pulls, Tobias
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Wästlund, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology.
    Towards Usable Privacy Policy Display & Management2012In: Information Management & Computer Security, ISSN 0968-5227, Vol. 20, 4-17 p.Article in journal (Refereed)
    Abstract [en]

    This paper discusses the approach taken within the PrimeLife project for providing user-friendly privacy policy interfaces for the PrimeLife Policy Language (PPL).We present the requirements, design process and usability testing of the “Send Data?” prototype, a browser extension designed and developed to deal with the powerful features provided by PPL. Our interface introduces the novel features of “on the fly” privacy management, predefined levels of privacy settings, and simplified selectionof anonymous credentials. Results from usability tests showed that users understand and appreciate these features and perceive them as being privacy-friendly, and they are therefore suggested as a good approach towards usable privacy policy display and management. Additionally, we present our lessons learnt in the design process of privacy policy interfaces.

  • 50.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    Pulls, Tobias
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Wästlund, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology.
    Usable Transparency with the Data Track: A Tool for Visualizing Data Disclosures2015In: CHI EA '15 Proceedings of the 33rd Annual ACM Conference Extended Abstracts on Human Factors in Computing Systems / [ed] Bo Begole, Jinwoo Kim, Kori Inkpen, Woontack Woo, Association for Computing Machinery (ACM), 2015, 1803-18098 p.Conference paper (Refereed)
    Abstract [en]

    We present a prototype of the user interface of a transparency tool that displays an overview of a user's data disclosures to different online service providers and allows them to access data collected about them stored at the services' sides. We explore one particular type of visualization method consisting of tracing lines that connect a user's disclosed personal attributes to the service to which these attributes have been disclosed. We report on the ongoing iterative process of design of such visualization, the challenges encountered and the possibilities for future improvements.

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