Change search
Refine search result
1234567 1 - 50 of 2213
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abbas, Muhammad Tahir
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Jibran, Muhammad Ali
    Jeju Natl Univ, Dept Comp Engn, Jeju 63243, South Korea..
    Afaq, Muhammad
    Sarhad Univ Sci & Informat Technol, Pakistan..
    Song, Wang-Cheol
    Jeju Natl Univ, South Korea..
    An adaptive approach to vehicle trajectory prediction using multimodel Kalman filterIn: European transactions on telecommunications, ISSN 1124-318X, E-ISSN 2161-3915, article id e3734Article in journal (Refereed)
    Abstract [en]

    With the aim to improve road safety services in critical situations, vehicle trajectory and future location prediction are important tasks. An infinite set of possible future trajectories can exit depending on the current state of vehicle motion. In this paper, we present a multimodel-based Extended Kalman Filter (EKF), which is able to predict a set of possible scenarios for vehicle future location. Five different EKF models are proposed in which the current state of a vehicle exists, particularly, a vehicle at intersection or on a curve path. EKF with Interacting Multiple Model framework is explored combinedly for mathematical model creation and probability calculation for that model to be selected for prediction. Three different parameters are considered to create a state vector matrix, which includes vehicle position, velocity, and distance of the vehicle from the intersection. Future location of a vehicle is then used by the software-defined networking controller to further enhance the safety and packet delivery services by the process of flow rule installation intelligently to that specific area only. This way of flow rule installation keeps the controller away from irrelevant areas to install rules, hence, reduces the network overhead exponentially. Proposed models are created and tested in MATLAB with real-time global positioning system logs from Jeju, South Korea.

  • 2.
    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, p. 316-322Conference 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.

  • 3.
    Abrahamsson, Henrik
    et al.
    RISE SICS.
    Abdesslem, Fehmi Ben
    RISE SICS.
    Ahlgren, Bengt
    RISE SICS.
    Björkman, Mats
    Mälardalen University.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Marsh, Ian
    RISE SICS.
    Selecting Operator in 3G/4G Networks for Time-Critical C-ITS Applications2018Conference paper (Refereed)
  • 4.
    Abrahamsson, Henrik
    et al.
    RISE SICS, Stockholm, Sweden.
    Ben Abdesslem, Fehmi
    RISE SICS, Stockholm, Sweden.
    Ahlgren, Bengt
    RISE SICS, Stockholm, Sweden.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Marsh, Ian
    RISE SICS, Stockholm, Sweden.
    Bjorkman, Mats
    Mälardalens högskola.
    Connected Vehicles in Cellular Networks: Multi-access versus Single-access Performance2018In: 2018 NETWORK TRAFFIC MEASUREMENT AND ANALYSIS CONFERENCE (TMA), 2018Conference paper (Refereed)
    Abstract [en]

    Connected vehicles can make roads traffic safer and more efficient, but require the mobile networks to handle time-critical applications. Using the MONROE mobile broadband measurement testbed we conduct a multi-access measurement study on buses. The objective is to understand what network performance connected vehicles can expect in today's mobile networks, in terms of transaction times and availability. The goal is also to understand to what extent access to several operators in parallel can improve communication performance. In our measurement experiments we repeatedly transfer warning messages from moving buses to a stationary server. We triplicate the messages and always perform three transactions in parallel over three different cellular operators. This creates a dataset with which we can compare the operators in an objective way and with which we can study the potential for multi-access. In this paper we use the triple-access dataset to evaluate single-access selection strategies, where one operator is chosen for each transaction. We show that if we have access to three operators and for each transaction choose the operator with best access technology and best signal quality then we can significantly improve availability and transaction times compared to the individual operators. The median transaction time improves with 6% compared to the best single operator and with 61% compared to the worst single operator. The 90-percentile transaction time improves with 23% compared to the best single operator and with 65% compared to the worst single operator.

  • 5. Abu Bakar, Sakhinah
    et al.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Characterization of essential proteins in proteins interaction networks2013In: Journal of Quality Measurement and Analysis, ISSN 1823-5670, Vol. 9, no 2, p. 11-26Article in journal (Refereed)
  • 6.
    Adams, Paul C.
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Geography, Media and Communication (from 2013). University of Texas at Austin, USA.
    Geographies of media and communication II: Arcs of communication2018In: Progress in Human Geography, ISSN 0309-1325, E-ISSN 1477-0288, Vol. 42, no 4, p. 590-599Article in journal (Refereed)
    Abstract [en]

    Some of the most perceptive contributions to the geographic study of media and communication have been in areas of landscapes studies and geohumanities. To bring landscape and geohumanities insights together more explicitly with communication and media, this progress report draws on George Revill’s concept of an ‘arc of sound’, expanding the concept’s scope to an arc of communication – a dynamic trajectory connecting one vantage point to another through various translations and shifts. It is a mix of integration and translation that forms its own space, place and time, integrating elements of embodied performance, multiple sensory modalities, temporality, absence and excess. Arcs of communication often depend on collaboration and can produce transformations of identity. The concept of the arc of communication enables discovery of numerous threads connecting landscape studies to geohumanities while deepening geographical understandings of media and communication.

  • 7. Adams, Robin
    et al.
    Fischer, Sally
    Pears, Arnold
    Börstler, Jürgen
    Boustedt, Jonas
    Dalenius, Peter
    Eken, Gunilla
    Heyer, Tim
    Jacobsson, Andreas
    Lindberg, Vanja
    Molin, Bemgt
    Moström, Jan-Erik
    Wiggberg, Mattias
    What is the Word for "Engineering" in Swedisch: Swedish Students Conceptions of their Discipline2007Report (Refereed)
  • 8.
    Adamsson, Tim
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Karlstad Business School.
    Kravrekommendation: En undersökning för kravrekommendationer för Nya Intranätets forum på Karlstad Universitet2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 9.
    Afzal, Zeeshan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Towards Secure Multipath TCP Communication2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The evolution in networking coupled with an increasing demand to improve user experience has led to different proposals to extend the standard TCP. Multipath TCP (MPTCP) is one such extension that has the potential to overcome few inherent limitations in the standard TCP. While MPTCP's design and deployment progresses, most of the focus has been on its compatibility. The security aspect is confined to making sure that the MPTCP protocol itself offers the same security level as the standard TCP.

    The topic of this thesis is to investigate the unexpected security implications raised by using MPTCP in the traditional networking environment. The Internet of today has security middle-boxes that perform traffic analysis to detect intrusions and attacks. Such middle-boxes make use of different assumptions about the traffic, e.g., traffic from a single connection always arrives along the same path. This along with many other assumptions may not be true anymore with the advent of MPTCP as traffic can be fragmented and sent over multiple paths simultaneously.

    We investigate how practical it is to evade a security middle-box by fragmenting and sending traffic across multiple paths using MPTCP. Realistic attack traffic is used to evaluate such attacks against Snort IDS to show that these attacks are feasible. We then go on to propose possible solutions to detect such attacks and implement them in an MPTCP proxy. The proxy aims to extend the MPTCP performance advantages to servers that only support standard TCP, while ensuring that intrusions can be detected as before. Finally, we investigate the potential MPTCP scenario where security middle-boxes only have access to some of the traffic. We propose and implement an algorithm to perform intrusion detection in such situations and achieve a nearly 90% detection accuracy. Another contribution of this work is a tool, that converts IDS rules into equivalent attack traffic to automate the evaluation of a middle-box.

  • 10.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Partial Signature Matching in an MPTCP World using Insert-only Levenshtein DistanceManuscript (preprint) (Other academic)
  • 11.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Slice Distance: An Insert-Only Levenshtein Distance with a Focus on Security Applications2018In: Proceedings of NTMS 2018 Conference and Workshop, New York: IEEE, 2018, p. 1-5Conference paper (Refereed)
    Abstract [en]

    Levenshtein distance is well known for its use in comparing two strings for similarity. However, the set of considered edit operations used when comparing can be reduced in a number of situations. In such cases, the application of the generic Levenshtein distance can result in degraded detection and computational performance. Other metrics in the literature enable limiting the considered edit operations to a smaller subset. However, the possibility where a difference can only result from deleted bytes is not yet explored. To this end, we propose an insert-only variation of the Levenshtein distance to enable comparison of two strings for the case in which differences occur only because of missing bytes. The proposed distance metric is named slice distance and is formally presented and its computational complexity is discussed. We also provide a discussion of the potential security applications of the slice distance.

  • 12.
    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.
    Automated Testing of IDS Rules2015In: Software Testing, Verification and Validation Workshops (ICSTW), 2015 IEEE Eighth International Conference on, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    As technology becomes ubiquitous, new vulnerabilities are being discovered at a rapid rate. Security experts continuously find ways to detect attempts to exploit those vulnerabilities. The outcome is an extremely large and complex rule set used by Intrusion Detection Systems (IDSs) to detect and prevent the vulnerabilities. The rule sets have become so large that it seems infeasible to verify their precision or identify overlapping rules. This work proposes a methodology consisting of a set of tools that will make rule management easier.

  • 13.
    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.
    IDS rule management made easy2016In: Electronics, Computers and Artificial Intelligence (ECAI), 2016 8th International Conference on, IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    Signature-based intrusion detection systems (IDSs) are commonly utilized in enterprise networks to detect and possibly block a wide variety of attacks. Their application in industrial control systems (ICSs) is also growing rapidly as modem ICSs increasingly use open standard protocols instead of proprietary. Due to an ever changing threat landscape, the rulesets used by these IDSs have grown large and there is no way to verify their precision or accuracy. Such broad and non-optimized rulesets lead to false positives and an unnecessary burden on the IDS, resulting in possible degradation of the security. This work proposes a methodology consisting of a set of tools to help optimize the IDS rulesets and make rule management easier. The work also provides attack traffic data that is expected to benefit the task of IDS assessment.

  • 14.
    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, p. 265-282Conference 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.

  • 15.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lidén, Anders
    Towards Multipath TCP Aware Security Technologies2016In: 2016 8th IFIP International Conference onNew Technologies, Mobility and Security (NTMS), New York: IEEE, 2016, p. 1-8Conference 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.

  • 16.
    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.

  • 17.
    Afzal, Zeeshan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Rossebø, Judith
    Integrated Operations, ABB AS, Norway.
    Chowdhury, Mohammad
    Talha, Batool
    ABB Corporate Research, ABB AS, Norway.
    A Wireless Intrusion Detection System for 802.11 networks2016In: PROCEEDINGS OF THE 2016 IEEE INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS, SIGNAL PROCESSING AND NETWORKING (WISPNET), IEEE conference proceedings, 2016, p. 828-834Conference paper (Refereed)
    Abstract [en]

    Wireless local area networks (WLANs) deployment is increasing rapidly. At the same time, WLANs have become an attractive target for many potential attackers. In spite of that, the de facto standard used to implement most WLANs (IEEE 802.11) has what appear to be residual vulnerabilities related to identity spoofing. In this paper, a pragmatic study of two common attacks on the standard is conducted. These attacks are then implemented on test beds to learn attack behavior. Finally, novel attack signatures and techniques to detect these attacks are devised and implemented in a proof of concept Wireless Intrusion Detection System (WIDS).

  • 18.
    Agapi, Mesodiakaki
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zola, Enrica
    UPC BarcelonaTECH, Barcelona Spain.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Joint User Association and Backhaul Routing for Green 5G Mesh Millimeter Wave Backhaul Networks2017In: Proceedings Of The 20Th Acm International Conference On Modelling, Analysis And Simulation Of Wireless And Mobile Systems, ASSOC COMPUTING MACHINERY, , 2017, p. 179-186Conference paper (Refereed)
    Abstract [en]

    With the advance of fifth generation (5G) networks, network density needs to grow significantly in order to meet the required capacity demands. A massive deployment of small cells may lead to a high cost for providing. ber connectivity to each node. Consequently, many small cells are expected to be connected through wireless links to the umbrella eNodeB, leading to a mesh backhaul topology. This backhaul solution will most probably be composed of high capacity point-to-point links, typically operating in the millimeter wave (mmWave) frequency band due to its massive bandwidth availability. In this paper, we propose a mathematical model that jointly solves the user association and backhaul routing problem in the aforementioned context, aiming at the energy efficiency maximization of the network. Our study considers the energy consumption of both the access and backhaul links, while taking into account the capacity constraints of all the nodes as well as the fulfillment of the service-level agreements (SLAs). Due to the high complexity of the optimal solution, we also propose an energy efficient heuristic algorithm (Joint), which solves the discussed joint problem, while inducing low complexity in the system. We numerically evaluate the algorithm performance by comparing it not only with the optimal solution but also with reference approaches under different traffic load scenarios and backhaul parameters. Our results demonstrate that Joint outperforms the state-of-the-art, while being able to find good solutions, close to optimal, in short time.

  • 19.
    Agapi, Mesodiakaki
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zola, Enrica
    Univ Politecn Cataluna, Dept Network Engn, Barcelona, Spain.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    User Association in 5G Heterogeneous Networks with Mesh Millimeter Wave Backhaul Links2017In: 2017 IEEE 18th International Symposium on A World of Wireless, Mobile and Multimedia Networks (WoWMoM), IEEE, 2017Chapter in book (Other academic)
    Abstract [en]

    Fifth generation (5G) wireless networks will target at energy and spectrum efficient solutions to cope with the increasing demands in capacity and energy efficiency. To achieve this joint goal, dense networks of small cells (SCs) are expected to overlay the existing macro cells. In parallel, for the SC connection to the core network, a promising solution lies in a mesh network of high capacity millimeter wave backhaul (BH) links. In the considered 5G architecture, each SC is able to forward its BH traffic to the core network through alternative paths, thus offering high BIT network reliability. In this context, the joint problem of user association and HI routing becomes challenging. In this paper, we focus on this problem targeting at energy and spectrum efficient solutions. A low-complexity algorithm is proposed, which bases its user association and BIT routing decision i) on minimizing the spectrum resources to guarantee the user rate, so as to provide high spectrum efficiency, and ii) on minimizing both the access network and BH route power consumption to provide high energy efficiency. Our results show that our solution provides better trade-offs between energy and spectrum efficiency than the state-of-the-art in 3GPP scenarios.

  • 20.
    Aguiño, Gonzalo Iglesias
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Performance of VoIP strategies for hybrid Mobile Ad Hoc Networks2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Last decade, a lot of research has been done in wireless communication technologies. Mobile

    nodes such personal digital assistants (PDAs), notebooks and cell phones are nowadays used

    in human’s daily life.

    MANETs are networks consisting of two or more mobile nodes equipped with wireless

    communication and networking capabilities, but they don’t have any network centrilized

    infrastructure.

    In last few years, MANETs have been emerged to be an important researched subject in the

    field of wireless networking.

    MANETs are autonomous; however they can communicate with other external networks such

    the internet. They are linked to such external networks by mobile nodes acting as gateways.

    This kind of networks is known as hybrid MANETs.

    Voice over Internet Protocol (VoIP), is a technology that allows you to make voice calls using

    a Internet connection instead of a regular (or analog) phone line.

    The goal of this thesis is evaluate the performance of VoIP strategies for hybrid MANETs.

    Two different aspects are evaluated, the session establishment performance and the voice

    quality.

    Network Simulator 2 is used to run several simulations, two different applications are used to

    run voice simulations (Session Initiation Protocol and Exponential traffic generator). We

    evaluate two different cases for voice traffics, voice calls between two MANET nodes and

    voice calls between MANET nodes and external nodes.

    After running the simulations, there are some performance parameters which will reveal the

    results. The key findings of the simulations are: adding gateways, number of voice traffic

    flows and the number of hops between source and destinations. There are some interesting

    results which reveal for example, that adding gateways is not always beneficial.

  • 21. 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

  • 22. 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

  • 23.
    Ahammed, Farhan
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Finding lower bounds of localization with noisy measurements using genetic algorithms2011In: Proceedings of the first ACM international symposium on Design and analysis of intelligent vehicular networks and applications (DIVANet '11), Miami, Florida, USA: Association for Computing Machinery (ACM), 2011, p. 47-54Conference paper (Refereed)
    Abstract [en]

    Vehicular Ad-Hoc Networks (VANETs) are wireless networks with mobile nodes (vehicles) which connect in an ad-hoc manner. Many vehicles use the Global Positioning System (GPS) to provide their locations. However the inaccuracy of GPS devices leads to some vehicles incorrectly assuming they are located at different positions and sometimes on different roads. VANETs can be used to increase the accuracy of each vehicle's computed location by allowing vehicles to share information regarding the measured distances to neighbouring vehicles. This paper looks at finding how much improvement can be made given the erroneous measurements present in the system. An evolutionary algorithm is used to evolve instances of parameters used by the VLOCI2 algorithm, also presented in this paper, to find instances which minimises the inaccuracy in computed locations. Simulation results show a definite improvement in location accuracy and lower bounds on how much improvement is possible is inferred.

  • 24. Ahammed, Farhan
    et al.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Finding Lower Bounds of Localization with Noisy Measurements Using Genetic Algorithms2011Report (Refereed)
  • 25.
    Ahammed, Farhan
    et al.
    The University of Sydney, Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Using simulated annealing to find lower bounds of localization with noisy measurements2012In: 2012 IEEE 26th International Parallel and Distributed Processing Symposium Workshops & PhD Forum (IPDPSW), IEEE conference proceedings, 2012, p. 601-608Conference paper (Refereed)
  • 26.
    Ahammed, Farhan
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Ott, Max
    NICTA Australia Australian Technology Park.
    LICA: Improving Localization Given Noisy Data In GPS-Equipped VANETs Using Trilateration With Cluster Analysis2011Report (Refereed)
  • 27.
    Ahammed, Farhan
    et al.
    University of Sydney.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Ott, Max
    NICTA.
    VLOCI: Using Distance Measurements to Improve the Accuracy of Location Coordinates in GPS-Equipped VANETs2012In: Mobile and Ubiquitous Systems: 7th International ICST Conference, MobiQuitous 2010, Sydney, Australia, December 6-9, 2010, Revised Selected Papers / [ed] Patrick Sénac, Max Ott, Aruna Seneviratne, Springer Berlin/Heidelberg, 2012, Vol. 73, p. 149-161Conference paper (Refereed)
  • 28.
    Ahammed, Farhan
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Ott, Max
    NICTA Australia Australian Technology Park.
    VLOCI2: An Iterative Method To Improve Location Coordinates In GPS-Equipped VANETs in Multiple Lanes2011Report (Refereed)
  • 29.
    Ahammed, Farhan
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Ott, Max
    Australian Technology Park, Australia.
    VLOCI2: An Iterative Method To Improve Location Coordinates In GPS-Equipped VANETs in Multiple Lanes2011Report (Refereed)
  • 30.
    Ahl, Elin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Nordberg, Nina
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Planning a digital transformation for a company with a process layout: A study conducted at voestalpine Precision Strip AB2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Digitalization is an upcoming trend that divides the manufacturing industry of today. As an increasing number of companies chose to implement digitalization as a business strategy, some companies still struggle with implementing digitalization into their businesses.

    Previous research has developed digital transformation models, but has been admitted as too generic. This thesis used the most comprehensive transformation model as base and aimed to make it practically implementable for a manufacturing company with a process layout. To enable this, a case study was conducted on a steel-processing company with this layout design. This thesis had an inductive approach, where primary data were collected from one selected company through a pilot study and semi structured interviews, and secondary data were collected through a literature review.

    During the study, it was discovered that a company can benefit from using a customized guidance of how to implement digitalization, to optimally use digital opportunities. This thesis contributed with additional steps and extensions of the previous transformation model. The contribution consisted of the involvement of competency, creation of definition, identified digitalization trends relating to a SWOT analysis, additional phenomenon to take into consideration when analyzing future scenarios, additional questions to consider when analyzing impacted areas, creation of a digital business strategy, a comparison of impacted areas with previous projects, additional identified actions to fill the gap between current state and goals, and five identified criteria’s on how to prioritize these actions. This study extends current research with details and depth regarding a digital transformation model, and hence make it more practical. For future research, a case study testing the potential of the transformation model on a similar company should be conducted, and thereby improve the model further.

  • 31.
    Ahlberg, Lina
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Karlstad Business School (from 2013).
    Smarta glasögons användbarhet: Hur användarnas datorvana påverkar användbarheten av smarta glasögon2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Smarta glasögon är interaktiva glasögon som har en inbyggd dator och tillåter användaren att se en bildskärm samtidigt som den materiella omgivningen kan ses. Studiens syfte är att undersöka hur användarens datorvana påverkar den upplevda användbarheten av smarta glasögon. Genomförandet av undersökningen har bestått av att 34 respondenter genomfört ett användartest följt av en strukturerad intervju. Intervjuerna har sedan kategoriserats beroende av datorvana och respondenternas upplevelser, vilket har legat till grund för analysen. För att styrka analysen har en litteraturstudie genomförts av tidigare teori inom ämnena skillnader mellan individer, användbarhet och smarta glasögon. Studiens slutsatser visar på att det inte finns några tydliga skillnader i användarnas upplevelser till följd av den tidigare datorvanan. De skillnader som ändå identifierades är att det finns indikationer på att upplevelsen av svårigheter och effektivitet till viss del påverkats av datorvanan.

  • 32.
    Ahmad, Muhammad Ovais
    et al.
    University of Oulu, Finland.
    Liukkunen, Kari
    University of Oulu, Finland .
    Markkula, Jouni
    University of Oulu, Finland.
    Student perceptions and attitudes towards the software factory as a learning environment2014Conference paper (Refereed)
    Abstract [en]

    Industry needs graduates from universities having knowledge and skills to tackle the practical issues of real life software development. To facilitate software engineering students and fulfill industry need, the Department of Information Processing Science, University of Oulu, Finland, built a Software Factory laboratory (SWF) in 2012 based on Lean concept. This study examines factors in the SWF learning environment that affect learning of a SWF course by the students. It employs amended Computer laboratory Environment Inventory (CLEI) and Attitude towards Computers and Computing Courses Questionnaire instrument (ACCC) with two additional constructs: 1) Kanban board 2) Collaborative learning. The general findings indicate that SWF learning environment, collaborative learning and Kanban board play important role in software engineering students learning, academic achievements and professional skills gaining. The findings are helpful to develop a better understanding about learning environments. The information gathered in this study can also be used to improve the software engineering learning environment.

  • 33.
    Ahmed, Bestoun S.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bures, Miroslav
    Czech Technical University, Czech Republic.
    EvoCreeper: Automated Black-Box Model Generation for Smart TV Applications2019In: IEEE transactions on consumer electronics, ISSN 0098-3063, E-ISSN 1558-4127, Vol. 65, no 2, p. 160-169Article in journal (Refereed)
    Abstract [en]

    Abstract—Smart TVs are coming to dominate the televisionmarket. This accompanied by an increase in the use of the smartTV applications (apps). Due to the increasing demand, developersneed modeling techniques to analyze these apps and assess theircomprehensiveness, completeness, and quality. In this paper, wepresent an automated strategy for generating models of smartTV apps based on a black-box reverse engineering. The strategycan be used to cumulatively construct a model for a given app byexploring the user interface in a manner consistent with the use ofa remote control device and extracting the runtime information.The strategy is based on capturing the states of the user interfaceto create a model during runtime without any knowledge ofthe internal structure of the app. We have implemented ourstrategy in a tool called EvoCreeper. The evaluation results showthat our strategy can automatically generate unique states anda comprehensive model that represents the real user interactionswith an app using a remote control device. The models thusgenerated can be used to assess the quality and completeness ofsmart TV apps in various contexts, such as the control of otherconsumer electronics in smart houses.

  • 34.
    Ahmed, Bestoun S.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bures, Miroslav
    Czech Technical University in Prague, Prague.
    Frajtak, Karel
    Czech Technical University in Prague, Prague.
    Cerny, Tomas
    Baylor University, Waco.
    Aspects of Quality in Internet of Things (IoT) Solutions: A Systematic Mapping Study2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 13758-13780Article in journal (Refereed)
    Abstract [en]

    Internet of Things (IoT) is an emerging technology that has the promising power to change our future. Due to the market pressure, IoT systems may be released without sufficient testing. However, it is no longer acceptable to release IoT systems to the market without assuring the quality. As in the case of new technologies, the quality assurance process is a challenging task. This paper shows the results of the first comprehensive and systematic mapping study to structure and categories the research evidence in the literature starting in 2009 when the early publication of IoT papers for IoT quality assurance appeared. The conducted research is based on the most recent guidelines on how to perform systematic mapping studies. A set of research questions is defined carefully regarding the quality aspects of the IoT. Based on these questions, a large number of evidence and research papers is considered in the study (478 papers). We have extracted and analyzed different levels of information from those considered papers. Also, we have classified the topics addressed in those papers into categories based on the quality aspects. The study results carry out different areas that require more work and investigation in the context of IoT quality assurance. The results of the study can help in a further understanding of the research gaps. Moreover, the results show a roadmap for future research directions.

  • 35.
    Ahmed, Bestoun S.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Pahim, Amador
    Red Hat Czech s.r.o., Brno, Czech Republic .
    Rosa Junior, Cleber R
    Red Hat, Inc., Westford, USA .
    Kuhn, D. Richard
    Natl Inst of Standards and Technology, Gaithersburg, MD, USA .
    Bures, Miroslav
    Dept of Computer Science, Czech Technical Univ, Prague, Czech Republic .
    Towards an Automated Unified Framework to Run Applications for Combinatorial Interaction Testing2019In: EASE '19 Proceedings of the Evaluation and Assessment on Software Engineering, NY, USA: ACM Digital Library, 2019, p. 252-258Conference paper (Refereed)
    Abstract [en]

    Combinatorial interaction testing (CIT) is a well-known technique,but the industrial experience is needed to determine its effectivenessin different application domains. We present a case study introducinga unified framework for generating, executing and verifyingCIT test suites, based on the open-source Avocado test framework.In addition, we present a new industrial case study to demonstratethe effectiveness of the framework. This evaluation showed thatthe new framework can generate, execute, and verify effective combinatorialinteraction test suites for detecting configuration failures(invalid configurations) in a virtualization system.

  • 36.
    Airola, Rasmus
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Hager, Kristoffer
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Image Classification, Deep Learning and Convolutional Neural Networks: A Comparative Study of Machine Learning Frameworks2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The use of machine learning and specifically neural networks is a growing trend in software development, and has grown immensely in the last couple of years in the light of an increasing need to handle big data and large information flows. Machine learning has a broad area of application, such as human-computer interaction, predicting stock prices, real-time translation, and self driving vehicles. Large companies such as Microsoft and Google have already implemented machine learning in some of their commercial products such as their search engines, and their intelligent personal assistants Cortana and Google Assistant.

    The main goal of this project was to evaluate the two deep learning frameworks Google TensorFlow and Microsoft CNTK, primarily based on their performance in the training time of neural networks. We chose to use the third-party API Keras instead of TensorFlow's own API when working with TensorFlow. CNTK was found to perform better in regards of training time compared to TensorFlow with Keras as frontend. Even though CNTK performed better on the benchmarking tests, we found Keras with TensorFlow as backend to be much easier and more intuitive to work with. In addition, CNTKs underlying implementation of the machine learning algorithms and functions differ from that of the literature and of other frameworks. Therefore, if we had to choose a framework to continue working in, we would choose Keras with TensorFlow as backend, even though the performance is less compared to CNTK.

  • 37.
    Aitenbichler, Erwin
    et al.
    Technische Universität Darmstadt, Germany.
    Behring, Alexander
    Technische Universität Darmstadt, Germany.
    Bradler, Dirk
    Technische Universität Darmstadt, Germany.
    Hartmann, Melanie
    Technische Universität Darmstadt, Germany.
    Martucci, Leonardo
    Technische Universität Darmstadt, Germany.
    Mühlhäuser, Max
    Technische Universität Darmstadt, Germany.
    Ries, Sebastian
    Technische Universität Darmstadt, Germany.
    Schnelle-Walka, Dirk
    Technische Universität Darmstadt, Germany.
    Schreiber, Daniel
    Technische Universität Darmstadt, Germany.
    Steimle, Jürgen
    Technische Universität Darmstadt, Germany.
    Strufe, Thorsten
    Technische Universität Darmstadt, Germany.
    Shaping the Future Internet2009In: Proceedings of the 3rd International CompanionAble Workshop IoPTS, Brussels, 2. December 2009., The CompanionAble , 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.

  • 38.
    Al-abuhalje, Afrah
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Al-abuhalje, Sanaa
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Översikt och tillämpning av XML2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    Abstract

    HTML is not powerful enough to handle the increasing demands on Internet applications of today, which is one of the reasons to why a new markup language called XML has been introduced. In this report we describe the basics as well as more advanced parts of XML like DTD, XML Schema and XSLT.

    XML combines the simplicity of HTML and the possibilties of SGML. One of the premier strengths of XML is that it may be used to store any type of data without any considerations to how it will be presented later. The content and the presentation are separated completely. Another important property is that XML documents are stored as

    ordinary text files, which means that XML is system and platform independent.

    In this report our aim consists of two goals. One goal is to create a suitable format for storing configuration data using XML. The configuration data is to be used by a network emulator. In order to emulate the conditions present in a real network the emulator is

    capable of emulating things as bit errors, packet losses, bandwidth limitation and delay, all of which are examples of configuration data. The other goal is to describe the basics as well as more advanced parts of XML in general. As we describe XML, we continuously show how we apply this knowledge to our application. In this way, the reader achieves a good insight into how XML works.

  • 39.
    Ala-Häivälä, Anders
    Karlstad University, Faculty of Social and Life Sciences.
    Batch-digitalisering och GIS-anpassning av analoga enkätdata2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    This report describes the work with utilizing and adapting data from a visitor poll for use in a GIS. The poll was performed by the Municipality of Karlstad and the Swedish Forest Agency to survey peoples visit patterns in the I2-Forest, a former military training field which is now used as a recreation area. The poll consists of a number of questions about the visitor’s activities, age, opinions etc, and a map on which the visitor has drawn his or her path through the forest. Source data is a database containing poll answers, and the original maps with the drawn information. The task is partly to investigate if the maps can be batch-digitalized through scanning and vectorization, and partly to normalize the database.

    A method for digitalizing has been developed and tested on a selection of the maps. The method consists of a number of steps, including image processing, classification and vectorization. According to lack of batch-possibilities in the used GIS software, macros have been created by programming in VBA. The method works well on the selected maps and the conclusion is that it is possible to digitalize the drawn lines automatically. However, there are some shortages regarding accuracy and usability. Furthermore, the selection is relatively small and some adjustments on the settings for classification and vectorization might be necessary when applying the method on a larger part of the data.

    The database has been normalized as far as reasonable with consideration of performance and usability. To enable reliable searches, several attributes has been interpreted and modified through categorization and classification.

    The result is a geodatabase consisting of all poll answers, and the selected data from the digitalization test. To show how the database can be used, two simple examples of analyses have been made.

  • 40.
    Alaqra, Ala Sarah
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    The Wicked Problem of Privacy: Design Challenge for Crypto-based Solutions2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Data privacy has been growing in importance in recent years, especially with the continuous increase of online activity. Researchers study, design, and develop solutions aimed at enhancing users’ data privacy. The wicked problem of data privacy is a continuous challenge that defies straightforward solutions. Since there are many factors involved in data privacy, such as technological, legal, and human aspects, we can only aim at mitigating rather than solving this wicked problem. Our aim was to focus on human aspects for designing usable crypto-based privacy-enhancing solutions.  In this thesis, we followed a user centered design method by using empirical qualitative means for investigating user’s perceptions and opinions of our solutions. Most of our work has focused on redactable signatures in the cloud context within the eHealth use-case. Redactable signatures are  a privacy enhancing scheme allowing to remove parts of a signed document by a specified party for achieving data minimization without invalidating the respective signature.

    We mainly used semi-structures interviews and focus groups in our investigations. Our results yielded key HCI considerations as well as guidelines of different means for supporting the design of future solutions.

  • 41.
    Alaqra, Alaa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Framner, Erik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Enhancing Privacy Controls for Patients via a Selective Authentic Electronic Health Record Exchange Service: Qualitative Study of Perspectives by Medical Professionals and Patients2018In: Journal of Medical Internet Research, ISSN 1438-8871, E-ISSN 1438-8871, Vol. 20, no 12, article id e10954Article in journal (Refereed)
    Abstract [en]

    Background: Patients' privacy is regarded as essential for the patient-doctor relationship. One example of a privacy-enhancing technology for user-controlled data minimization on content level is a redactable signature. It enables users to redact personal information from signed documents while preserving the validity of the signature, and thus the authenticity of the document. In this study, we present end users' evaluations of a Cloud-based selective authentic electronic health record (EHR) exchange service (SAE-service) in an electronic health use case. In the use case scenario, patients were given control to redact specified information fields in their EHR, which were signed by their doctors with a redactable signature and transferred to them into a Cloud platform. They can then selectively disclose the remaining information in the EHR, which still bears the valid digital signature, to third parties of their choice. Objective: This study aimed to explore the perceptions, attitudes, and mental models concerning the SAE-service of 2 user roles: signers (medical professionals) and redactors (patients with different technical knowledge) in Germany and Sweden. Another objective was to elicit usability requirements for this service based on the analysis of our investigation. Methods: We chose empirical qualitative methods to address our research objective. Designs of mock-ups for the service were used as part of our user-centered design approach in our studies with test participants from Germany and Sweden. A total of 13 individual walk-throughs or interviews were conducted with medical staff to investigate the EHR signers' perspectives. Moreover, 5 group walk-throughs in focus groups sessions with (N=32) prospective patients with different technical knowledge to investigate redactor's perspective of EHR data redaction control were used. Results: We found that our study participants had correct mental models with regard to the redaction process. Users with some technical models lacked trust in the validity of the doctor's signature on the redacted documents. Main results to be considered are the requirements concerning the accountability of the patients' redactions and the design of redaction templates for guidance and control. Conclusions: For the SAE-service to be means for enhancing patient control and privacy, the diverse usability and trust factors of different user groups should be considered.

  • 42.
    Alaqra, Ala(a)
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    Groß, Thomas
    Newcastle University, Newcastle, UK.
    Lorünser, Thomas
    Austrian Institute of Technology, Vienna, Austria.
    Slamanig, Daniel
    Graz University of Technology, Graz, Austria.
    Signatures for Privacy, Trust and Accountability in the Cloud: Applications and Requirements2015In: Privacy and Identity Management. Time for a Revolution?: 10th IFIP WG 9.2, 9.5, 9.6/11.7, 11.4, 11.6/SIG 9.2.2 International Summer School, Edinburgh, UK, August 16-21, 2015, Revised Selected Papers / [ed] David Aspinall, Jan Camenisch, Marit Hansen, Simone Fischer-Hübner, Charles Raab, Springer Publishing Company, 2015, Vol. 476, p. 79-96Conference paper (Refereed)
    Abstract [en]

    This paper summarises the results of a workshop at the IFIP Summer School 2015 introducing the EU Horizon 2020 project PRISMACLOUD, that is, Privacy and Security Maintaining Services in the Cloud. The contributions of this summary are three-fold. Firstly, it provides an overview to the PRISMACLOUD cryptographic tools and use-case scenarios that were presented as part of this workshop. Secondly, it distills the discussion results of parallel focus groups. Thirdly, it summarises a ``Deep Dive on Crypto'' session that offered technical information on the new tools. Overall, the workshop aimed at outlining application scenarios and eliciting end-user requirements for PRISMACLOUD.

  • 43.
    Alaqra, Alaa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Pettersson, John
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Centre for HumanIT.
    Wästlund, Erik
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Service Research Center.
    Stakeholders’ Perspectives on Malleable Signatures in a Cloud-based eHealth Scenario2016In: Proceedings of the International Symposium on Human Aspects of Information Security & Assurance, 2016Conference paper (Refereed)
    Abstract [en]

    In this paper, we discuss end user requirements that we elicited for the use of malleable signatures in a Cloud-based eHealth scenario. The concept of a malleable signature, which is a privacy enhancing cryptographic scheme that enables the redaction of personal information from signed documents while preserving the validity of the signature, might be counter- intuitive to end users as its functionality does not correspond to the one of a traditional signature scheme. A qualitative study via a series of semi-structured interviews and focus groups has been conducted to understand stakeholders’ opinions and concerns in regards to the possible applications of malleable signatures in the eHealth area, where a medical record is first digitally signed by a doctor and later redacted by the patient in the cloud. Results from this study yielded user requirements such as the need for suitable metaphors and guidelines, usable templates, and clear redaction policies. 

  • 44.
    Alay, Özgü
    et al.
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    García, Rafael
    IMDEA Networks Institute, Spain.
    Peón Quirós, Miguel
    IMDEA Networks Institute, Spain.
    Mancuso, Vincenzo
    IMDEA Networks Institute, Spain.
    Hirsch, Thomas
    Celerway AS, Norway.
    Dely, Tobias
    Celerway AS, Norway.
    Werme, Jonas
    Celerway AS, Norway.
    Evensen, Kristian
    Celerway AS, Norway.
    Hansen, Audun
    Celerway AS, Norway.
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Karlsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Safari Khatouni, Ali
    Politecnico di Torino.
    Mellia, Marco
    Politecnico di Torino.
    Ajmone Marsan, Marco
    Politecnico di Torino.
    Monno, Roberto
    Nextworks, Italy.
    Lønsethagen, Håkon
    Telenor R&D, Norway.
    MONROE, a distributed platform to measure and assess mobile broadband networks: demo2016In: Proceedings of the Tenth ACM International Workshop on Wireless Network Testbeds, Experimental Evaluation, and Characterization, New York, NY, USA: Association for Computing Machinery (ACM), 2016, p. 85-86Conference paper (Refereed)
    Abstract [en]

    This demo presents the MONROE distributed platform and how it can be used to implement measurement and assessment experiments with operational mobile broadband networks (MBBs). MONROE provides registered experimenters with open access to hundreds of nodes, distributed over several European countries and equipped with multiple MBB connections, and a backend system that collects the measurement results. Experiments are scheduled through a user-friendly web client, with no need to directly access the nodes. The platform further embeds tools for real-time traffic flow analysis and a powerful visualization tool.

  • 45.
    Alay, Özgü
    et al.
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    Peón-Quirós, Miguel
    IMDEA Networks Institute, Spain.
    Mancuso, Vincenzo
    IMDEA Networks Institute, Spain.
    Hirsch, Thomas
    Celerway Communications, Norway.
    Evensen, Kristian
    Celerway Communications, Norway.
    Hansen, Audun
    Celerway Communications, Norway.
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Karlsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Safari Khatouni, Ali
    Politecnico di Torino, Italy.
    Mellia, Marco
    Politecnico di Torino, Italy.
    Ajmone Marsan, Marco
    IMDEA Networks Institute, Spain and Politecnico di Torino, Italy.
    Experience: An open platform for experimentation with commercial mobile broadband networks2017In: MobiCom '17 Proceedings of the 23rd Annual International Conference on Mobile Computing and Networking, New York: ACM Digital Library, 2017, p. 70-78Conference paper (Refereed)
    Abstract [en]

    Open experimentation with operational Mobile Broadband (MBB) networks in the wild is currently a fundamental requirement of the research community in its endeavor to address the need of innovative solutions for mobile communications. Even more, there is a strong need for objective data about stability and performance of MBB (e.g., 3G/4G) networks, and for tools that rigorously and scientifically assess their status. In this paper, we introduce the MONROE measurement platform: an open access and flexible hardware-based platform for measurements and custom experimentation on operational MBB networks. The MONROE platform enables accurate, realistic and meaningful assessment of the performance and reliability of 11 MBB networks in Europe. We report on our experience designing, implementing and testing the solution we propose for the platform. We detail the challenges we overcame while building and testing the MONROE testbed and argue our design and implementation choices accordingly. We describe and exemplify the capabilities of the platform and the wide variety of experiments that external users already perform using the system

  • 46.
    Alay, Özgü
    et al.
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    Rafael, García
    IMDEA Networks Institute, Spain.
    Peón Quirós, Miguel
    IMDEA Networks Institute, Spain.
    Mancuso, Vincenzo
    IMDEA Networks Institute, Spain.
    Hirsch, Thomas
    Celerway AS, Norway.
    Tobias, Dély
    Celerway AS, Norway.
    Werme, Jonas
    Celerway AS, Norway.
    Evensen, Kristian
    Celerway AS, Norway.
    Fosselie Hansen, Audun
    Celerway AS, Norway.
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Karlsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Safari Khatouni, Ali
    Politecnico di Torino, Italy.
    Mellia, Marco
    Politecnico di Torino, Italy.
    Ajmone Marsan, Marco
    Politecnico di Torino & IMDEA Networks, Italy.
    Monno, Roberto
    Nextworks, Italy.
    Lønsethagen, Håkon
    Telenor R&D, Norway.
    Measuring and Assessing Mobile Broadband Networks with MONROE2016In: 2016 IEEE International Symposium on a World of Wireless, Mobile, and Multimedia Networks (WoWMoM), Red Hook: IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    Mobile broadband (MBB) networks underpin numerous vital operations of the society and are arguably becoming the most important piece of the communications infrastructure. In this demo paper, our goal is to showcase the potential of a novel multi-homed MBB platform for measuring, monitoring and assessing the performance of MBB services in an objective manner. Our platform, MONROE, is composed of hundreds of nodes scattered over four European countries and a backend system that collects the measurement results. Through a user-friendly web client, the experimenters can schedule and deploy their experiments. The platform further embeds traffic analysis tools for real-time traffic flow analysis and a powerful visualization tool.

  • 47. Albert, Lars
    et al.
    Fredriksson, Odd
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management.
    Effektivisering av golvbranschen. En studie av struktur och lönsamhet samt några idéer till förändringar1986Report (Refereed)
  • 48.
    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.

  • 49.
    Ali, Nour
    et al.
    Brunel University, London, UK.
    Baker, Sean
    University of Limerick, Ireland.
    O’Crowley, Ross
    Red Orkid Limited, Dublin, Ireland.
    Herold, Sebastian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Buckley, Jim
    University of Limerick, Ireland.
    Architecture consistency: State of the practice, challenges and requirements2018In: Journal of Empirical Software Engineering, ISSN 1382-3256, E-ISSN 1573-7616, Vol. 23, no 1, p. 224-258Article in journal (Refereed)
    Abstract [en]

    Architecture Consistency (AC) aims to align implemented systems with their intended architectures. Several AC approaches and tools have been proposed and empirically evaluated, suggesting favourable results. In this paper, we empirically examine the state of practice with respect to Architecture Consistency, through interviews with nineteen experienced software engineers. Our goal is to identify 1) any practises that the companies these architects work for, currently undertake to achieve AC; 2) any barriers to undertaking explicit AC approaches in these companies; 3) software development situations where practitioners perceive AC approaches would be useful, and 4) AC tool needs, as perceived by practitioners. We also assess current commercial AC tool offerings in terms of these perceived needs. The study reveals that many practitioners apply informal AC approaches as there are barriers for adopting more formal and explicit approaches. These barriers are: 1) Difficulty in quantifying architectural inconsistency effects, and thus justifying the allocation of resources to fix them to senior management, 2) The near invisibility of architectural inconsistency to customers, 3) Practitioners’ reluctance towards fixing architectural inconsistencies, and 4) Practitioners perception that huge effort is required to map the system to the architecture when using more formal AC approaches and tools. Practitioners still believe that AC would be useful in supporting several of the software development activities such as auditing, evolution and ensuring quality attributes. After reviewing several commercial tools, we posit that AC tool vendors need to work on their ability to support analysis of systems made up of different technologies, that AC tools need to enhance their capabilities with respect to artefacts such as services and meta-data, and to focus more on non-maintainability architectural concerns.

  • 50. 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

1234567 1 - 50 of 2213
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf