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  • 301.
    Gregebo, Victor
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Nilsson, Jonas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Struktur på den digitala arbetsplatsen2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Begreppet den digitala arbetsplatsen kan ses som ett samlingsnamn för alla de verktyg och IT-system som används i det digitala arbetet. På den digitala arbetsplatsen behövs en intern kommunikationsstrategi för hur information ska hanteras för att effektivisera arbetet samt för att få en struktur i de digitala verktygen. Fabriken anser att intranätet är det verktyg som kopplar samman alla verktyg i den digitala arbetsplatsen.

    Kommunikationsstrategierna beskriver var anställda kan hitta eller dela information inom verksamheten. Saknas en kommunikationsstrategi kan nackdelar som redundans, duplicerad information och svårigheter att hitta rätt information förekomma.

    Målet med studien är att ta fram en intern kommunikationsstrategi samt se om intranätet kan bli navet i Fabrikens digitala arbetsplats. Kommunikationsstrategin har tagits fram genom informationsinsamling med hjälp av intervjuer och workshop. För att realisera kommunikationsstrategin var tanken att utveckla en Proof of Concept (PoC) för att visa Fabriken vilka möjligheter strategin innebär om intresse för vidareutveckling finns. Denna PoC utvecklades dock aldrig på grund av tidsbrist.

    Studien resulterade i en kommunikationsstrategi samt förslag på förändringar på intranätet. Förändringarna omfattar bland annat intranätets tillgänglighet samt en lösning i form av en kunskapsbank.

  • 302.
    Greschbach, Benjamin
    et al.
    KTH Royal Institute of Tech. .
    Pulls, Tobias
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Roberts, Laura M.
    Princeton University.
    Winter, Philipp
    Princeton University.
    Feamster, Nick
    Princeton University.
    The Effect of DNS on Tor´s Anonymity2017Ingår i: NDSS Symposium 2017, Internet society , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Previous attacks that link the sender and receiver oftraffic in the Tor network (“correlation attacks”) have generallyrelied on analyzing traffic from TCP connections. The TCPconnections of a typical client application, however, are oftenaccompanied by DNS requests and responses. This additionaltraffic presents more opportunities for correlation attacks. Thispaper quantifies how DNS traffic can make Tor users more vulnerableto correlation attacks. We investigate how incorporatingDNS traffic can make existing correlation attacks more powerfuland how DNS lookups can leak information to third partiesabout anonymous communication. We (i) develop a method toidentify the DNS resolvers of Tor exit relays; (ii) develop a newset of correlation attacks (DefecTor attacks) that incorporate DNStraffic to improve precision; (iii) analyze the Internet-scale effectsof these new attacks on Tor users; and (iv) develop improvedmethods to evaluate correlation attacks. First, we find that thereexist adversaries that can mount DefecTor attacks: for example,Google’s DNS resolver observes almost 40% of all DNS requestsexiting the Tor network. We also find that DNS requests oftentraverse ASes that the corresponding TCP connections do nottransit, enabling additional ASes to gain information about Torusers’ traffic. We then show that an adversary that can mount aDefecTor attack can often determine the website that a Tor useris visiting with perfect precision, particularly for less popularwebsites where the set of DNS names associated with that websitemay be unique to the site. We also use the Tor Path Simulator(TorPS) in combination with traceroute data from vantage pointsco-located with Tor exit relays to estimate the power of AS-leveladversaries that might mount DefecTor attacks in practice.

  • 303.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Bozakov, Zdravko
    Dell EMC.
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Isabel Bueno, María
    Damjanovic, Dragana
    Mozilla.
    Rikter Evensen, Kristian
    Celerway.
    Fairhurst, Gorry
    University of Aberdeen, UK..
    Hansen, Audun
    Celerway.
    Hayes, David
    University of Oslo, Norway.
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Khademi, Naeem
    University of Oslo, Norway.
    Mangiante, Simone
    Dell EMC.
    Mohideen, Althaff
    University of Aberdeen, UK..
    Rajiullah, Mohammad
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Ros, David
    Simula.
    Rüngeler, Irene
    FH Münster, Germany.
    Santos, Ricardo
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Secchi, Raffaello
    University of Aberdeen, UK..
    Christian Tangenes, Tor
    Tüxen, Micheal
    FH Münster, Germany.
    Weinrank, Felix
    FH Münster, Germany.
    Welzl, Michael
    University of Oslo, Norway.
    Deliverable D3.1 - Initial Report on the Extended Transport System2017Rapport (Refereegranskat)
    Abstract [en]

    The NEAT System offers an enhanced API for applications that disentangles them from the actual transport protocol being used. The system also enables applications to communicate their service requirements to the transport system in a generic, transport-protocol independent way. Moreover, the architecture of the NEAT System promotes the evolution of new transport services. Work Package 3 (WP3) enhances and extends the core parts of the NEAT Transport. Efforts have been devoted to developing transport-protocol mechanisms that enable a wider spectrum of NEAT Transport Services, and that assist the NEAT System in facilitating several of the commercial use cases. Work has also started on the development of optimal transport-selection mechanisms; mechanisms that enable for the NEAT System to make optimal transport selections on the basis of application requirements and network measurements. Lastly, another research activity has been initiated on how to use SDN to signal application requirements to routers, switches, and similar network elements. This document provides an initial report on all these WP3 activities—both on completed and on near-termplanned work.

  • 304.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Bozakov, Zdravko
    Dell EMC.
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Isabel Sanchez Bueno, Maria
    Dreibholz, Thomas
    Simula.
    Rikter Evensen, Kristian
    Celerway.
    Fairhurst, Gorry
    University of Aberdeen, UK..
    Fosselie Hansen, Audun
    Celerway.
    Hayes, David
    University of Oslo, Norway.
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Rajiullah, Mohammad
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Jones, Tom
    University of Aberdeen, UK..
    Ros, David
    Simula.
    Rozensztrauch, Tomasz
    Celerway.
    Tüxen, Michael
    FH Münster, Germany.
    Vyncke, Eric
    CISCO.
    Deliverable D3.3 - Extended Transport System and Transparent Support of Non-NEAT Applications2017Rapport (Refereegranskat)
    Abstract [en]

    This deliverable summarises and concludes our work in Work Package 3 (WP3) to extend the transport services provided by the NEAT System developed in Work Package 2, and to enable non-NEAT applications to harness the transport services offered by NEAT. We have demonstrated how a policy- and information-based selection of transport protocol by NEAT could provide a more efficient transport service for web applications. The information on which NEAT makes its transport selection decisions resides in the Characteristics Information Base (CIB). The CIB is populated by various CIB sources, and in WP3 we have designed, implemented, and evaluated various CIB sources, including meta data from mobile broadband networks, passive measurements, IPv6 Provisioning Domain protocols and the Happy Eyeballs mechanism, which caches the outcome of its connection attempts. A key property of NEAT is that it not only “vertically” decouples applications from transport protocols, but also “horizontally”. Particularly, it enables applications to harness information about resource availability and policies from Software Defined Networking (SDN) controllers in managed networks, without these applications actually being SDN-aware. To extend the use of NEAT to non-NEAT applications, we have implemented a BSDcompatible sockets API on top of NEAT and a NEAT proxy that intercepts and replaces standard TCP connections with NEAT flows, i.e., with the transport solutions deemed most appropriate by NEAT.We have also proposed a way for non-NEAT applications to make use of NEAT through the deployment of NEAT-enabled virtual appliances in SDN-controlled networks: connections from these applications are routed via an SDN-controlled proxy that terminates the original connection and replaces it with a NEAT-selected connection.

  • 305.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Cheng, Jun
    Ericsson AB, Stockholm, Sweden.
    Using Concurrent Multipath Transfer to Improve the SCTP Startup Behavior for PSTN Signaling Traffic2014Ingår i: 2014 28TH INTERNATIONAL CONFERENCE ON ADVANCED INFORMATION NETWORKING AND APPLICATIONS WORKSHOPS (WAINA) / [ed] Barolli, L; Li, KF; Enokido, T; Xhafa, F; Takizawa, M, IEEE, 2014, s. 772-778Konferensbidrag (Refereegranskat)
    Abstract [en]

    Although latency in the Internet has gained much attention in the research community, the latency issues of mobile control signaling have received less attention, and this all the while many telecom operators are experiencing a several-hundred percent increase in signaling traffic over only a couple of years. We believe one way to address both the latency and increased signaling load of mobile networks, is to exploit concurrent transfer of signaling traffic over several paths a.k.a. concurrent multipath transfer. This paper studies whether or not SCTP extended with concurrent multipath transfer (CMT-SCTP) could provide a faster startup behavior than standard SCTP. The paper complements previous work on CMT-SCTP, and extends it to PSTN signaling traffic. The paper suggests that CMT-SCTP could give a faster startup behavior over paths with similar bandwidths and round-trip times, but that its behavior is sensitive to differences in round-trip time between the paths. Moreover, the paper suggests that provided CMT-SCTP is configured with large enough send and receive buffers, it could provide a faster startup behavior than standard SCTP over a multipath association, in spite of some of the paths having a packet-loss rate of several percent.

  • 306.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Brunström, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    A First Study on Using MPTCP to Reduce Latency for Cloud Based Mobile Applications2015Ingår i: 2015 IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATION (ISCC), IEEE, 2015, s. 64-69Konferensbidrag (Refereegranskat)
    Abstract [en]

    Currently, Multipath TCP (MPTCP) – a modifica- tion to standard TCP that enables the concurrent use of several network paths in a single TCP connection – is being standardized by IETF. This paper provides a comprehensive evaluation of the use of MPTCP to reduce latency and thus improve the quality of experience or QoE for cloud-based applications. In particular, the paper considers the possible reductions in latency that could be obtained by using MPTCP and multiple network paths between a cloud service and a mobile end user. To obtain an appreciation of the expected latency performance for different types of cloud traffic, three applications are studied, Netflix, Google Maps, and Google Docs, representing typical applications generating high-, mid-, and low-intensity traffic. The results suggest that MPTCP could provide significant latency reductions for cloud applications, especially for applications such as Netflix and Google Maps. Moreover, the results suggest that MPTCP offers a reduced latency despite a few percent packet loss, and in spite of limited differences in the round-trip times of the network paths in an MPTCP connection. Still, larger differences in the round-trip times seem to significantly increase the application latency, especially for Netflix, Google Maps, and similar applications. Thus, to become an even better alternative to these applications, this paper suggests that the MPTCP packet scheduling policy should be changed: Apart from the round-trip times of the network paths in a connection, it should also consider the difference in round-trip time between the network paths.

  • 307.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT.
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    A Survey of TCP-Friendly Congestion Control Mechanisms for Multimedia Traffic2003Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The stability and performance of the Internet to date have in a large part been due tothe congestion control mechanism employed by TCP. However, while the TCP congestioncontrol is appropriate for traditional applications such as bulk data transfer, it hasbeen found less than ideal for multimedia applications. In particular, audio and videostreaming applications have difficulties managing the rate halving performed by TCP inresponse to congestion. To this end, the majority of multimedia applications use eithera congestion control scheme which reacts less drastic to congestion and therefore oftenis more aggressive than TCP, or, worse yet, no congestion control whatsoever. Sincethe Internet community strongly fears that a rapid deployment of multimedia applicationswhich do not behave in a fair and TCP-friendly manner could endanger the currentstability and performance of the Internet, a broad spectrum of TCP-friendly congestioncontrol schemes have been proposed. In this report, a survey over contemporary proposalsof TCP-friendly congestion control mechanisms for multimedia traffic in the Internetis presented. A classification scheme is outlined which shows how the majority of theproposed congestion control schemes emanate from a relatively small number of designprinciples. Furthermore, we illustrate how these design principles have been applied ina selection of congestion control scheme proposals and actual transport protocols.

  • 308.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Fairhurst, Gorry
    University of Aberdeen, UK..
    Hayes, David
    University of Oslo, Norway.
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Khademi, Naeem
    University of Oslo, Norway.
    Ros, David
    Simula.
    Rüngeler, Irene
    FH Münster, Germany.
    Tüxen, Michael
    FH Münster, Germany.
    Weinrank, Felix
    FH Münster, Germany.
    Welzl, Michael
    University of Oslo, Norway.
    Deliverable D3.2 - Final Report on Transport Protocol Enhancements2017Rapport (Refereegranskat)
    Abstract [en]

    This deliverable provides a final report on the work on transport protocol enhancements done inWork Package 3. First, we report on the extensions made to the SCTP protocol that turn it into a viable alternative to TCP and allow to deliver a lower-latency transport service. Next, we describe our work to develop a framework for providing a deadline-aware, less-than-best-effort transport service, targeting background traffic and thus addressing requirements on NEAT from the EMC use case. We also present our efforts to design and implement a latency-aware scheduler for MPTCP, which enables NEAT to offer a transport service that meets the needs of latency-sensitive applications, and that efficiently utilises available network resources. Lastly, this document informs on our work on coupled congestion control for TCP, a mechanism that treats a bundle of parallel TCP flows between the same pair of hosts as a single unit. By efficiently multiplexing concurrent TCP flows, our coupled congestion control alleviates the effects of queueing, and tends to result in a more efficient usage of available bandwidth, where the flows’ aggregate capacity share can be apportioned based on application preferences.

  • 309.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Jones, Tom
    University of Aberdeen.
    Fairhurst, Gorry
    University of Aberdeen.
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Ros, David
    Simula Research Lab.
    NEAT - A New, Evolutive API and Transport-Layer Architecture for the Internet2016Ingår i: 12th Swedish National Computer Networking Workshop (SNCNW 2016), Sundsvall, Sweden., 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    There is a growing concern that the Internet trans- port layer has become ossified in the face of emerging novel applications, and that further evolution has become very difficult. This paper identifies requirements for a new transport layer and then proposes a conceptual architecture, the NEAT system, that we believe is both flexible and evolvable. Applications interface the NEAT system through an enhanced user API that decouples them from the operation of the transport protocols and the network features being used. In particular, applications provide the NEAT system with information about their traffic requirements, pre- specified policies, and measured network conditions. On the basis of this information, the NEAT system establishes and configures appropriate connections. 

  • 310.
    Grinnemo, Karl-Johan
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Jones, Tom
    University of Aberdeen, Aberdeen, U.K.
    Fairhurst, Gorry
    University of Aberdeen, Aberdeen, U.K.
    Ros, David
    Simula Research Laboratory, Oslo, Norway.
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Towards a Flexible Internet Transport Layer Architecture2016Ingår i: The 22nd IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN), Rome, Italy, June 2015 / [ed] IEEE, IEEE, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is a growing concern that the Internet trans- port layer has stagnated and become less adaptive to the requirements imposed by new applications, and that further evolution has become very difficult. This is because a fundamental assumption no longer holds: it can no longer be assumed that the transport layer is only in the scope of end-hosts. The success of TCP and UDP and the ubiquity of middleboxes have led to ossification of both the network infrastructure and the API presented to applications. This has led to the development of workarounds, and a range of point solutions that fail to cover many facets of the problem. To address this issue, this paper identifies requirements for a new transport layer and then proposes a conceptual architecture that we argue is both flexible and evolvable. This new architecture requires that applications interface to the transport at a higher abstraction level, where an application can express communication preferences via a new richer API. Protocol machinery can use this information to decide which of the available transport protocols is used. By placing the protocol machinery in the transport layer, the new architecture can allow for new protocols to be deployed and enable evolution of the transport layer. 

  • 311.
    Gruetzner, Simon
    et al.
    University of Bremen, Germany.
    Muntean, Adrian
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brief Introduction to Damage Mechanics and its Relation to Deformations2018Ingår i: Mathematical Analysis of Continuum Mechanics and Industrial Applications II / [ed] P. VanMeurs, M Kimura, H Notsu, Springer, 2018, Vol. 30, s. 115-124Konferensbidrag (Refereegranskat)
    Abstract [en]

    We discuss some principle concepts of damage mechanics and outline a possibility to address the open question of the damage-to-deformation relation by suggesting a parameter identification setting. To this end, we introduce a variable motivated by the physical damage phenomenon and comment on its accessibility through measurements. We give an extensive survey on analytic results and present an isotropic irreversible partial damage model in a dynamic mechanical setting in form of a second order hyperbolic equation coupled with an ordinary differential equation for the damage evolution. We end with a note on a possible parameter identification setting.

  • 312.
    Gupta, Lay
    et al.
    Washington Univ, Dept Comp Sci & Engn, St Louis, MO 63110 USA..
    Jain, Raj
    Washington Univ, Dept Comp Sci & Engn, St Louis, MO 63110 USA..
    Erbad, Aiman
    Qatar Univ, Dept Comp Sci & Engn, Doha, Qatar..
    Bhamare, Deval
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    The P-ART framework for placement of virtual network services in a multi-cloud environment2019Ingår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 139, s. 103-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carriers' network services are distributed, dynamic, and investment intensive. Deploying them as virtual network services (VNS) brings the promise of low-cost agile deployments, which reduce time to market new services. If these virtual services are hosted dynamically over multiple clouds, greater flexibility in optimizing performance and cost can be achieved. On the flip side, when orchestrated over multiple clouds, the stringent performance norms for carrier services become difficult to meet, necessitating novel and innovative placement strategies. In selecting the appropriate combination of clouds for placement, it is important to look ahead and visualize the environment that will exist at the time a virtual network service is actually activated. This serves multiple purposes - clouds can be selected to optimize the cost, the chosen performance parameters can be kept within the defined limits, and the speed of placement can be increased. In this paper, we propose the P-ART (Predictive-Adaptive Real Time) framework that relies on predictive-deductive features to achieve these objectives. With so much riding on predictions, we include in our framework a novel concept-drift compensation technique to make the predictions closer to reality by taking care of long-term traffic variations. At the same time, near real-time update of the prediction models takes care of sudden short-term variations. These predictions are then used by a new randomized placement heuristic that carries out a fast cloud selection using a least-cost latency-constrained policy. An empirical analysis carried out using datasets from a queuing-theoretic model and also through implementation on CloudLab, proves the effectiveness of the PART framework. The placement system works fast, placing thousands of functions in a sub-minute time frame with a high acceptance ratio, making it suitable for dynamic placement. We expect the framework to be an important step in making the deployment of carrier-grade VNS on multi-cloud systems, using network function virtualization (NFV), a reality.

  • 313.
    Gutmann, Andreas
    et al.
    Tech Univ Darmstadt, Darmstadt, Germany.
    Renaud, Karen
    Glasgow University, Scotland.
    Maguire, Joseph
    Glasgow University, Scotland.
    Mayer, Peter
    Tech Univ Darmstadt, Darmstadt, Germany.
    Volkamer, Melanie
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap. Tech Univ Darmstadt, Darmstadt, Germany.
    Matsuura, Kanta
    University Tokyo, Japan.
    Müller-Quade, Jörn
    Karlsruhe Inst Technol, Germany.
    ZeTA - Zero-Trust Authentication: Relying on Innate Human Ability, not Technology2016Ingår i: 2016 IEEE European Symposium on Security and Privacy (EuroS&P), IEEE, 2016, s. 357-371Konferensbidrag (Refereegranskat)
    Abstract [en]

    Reliable authentication requires the devices and channels involved in theprocess to be trustworthy; otherwise authentication secrets can easily becompromised. Given the unceasing efforts of attackers worldwide suchtrustworthiness is increasingly not a given. A variety of technicalsolutions, such as utilising multiple devices/channels and verificationprotocols, has the potential to mitigate the threat of untrustedcommunications to a certain extent. Yet such technical solutions make twoassumptions: (1) users have access to multiple devices and (2) attackerswill not resort to hacking the human, using social engineering techniques.In this paper, we propose and explore the potential of using human-basedcomputation instead of solely technical solutions to mitigate the threat ofuntrusted devices and channels. ZeTA (Zero  Trust Authentication on untrusted channels) has the potentialto allow people to authenticate despite compromised channels orcommunications and easily observed usage. Our contributions are threefold:(1) We propose the ZeTA protocol with a formal definition and securityanalysis that utilises semantics and human-based computation to amelioratethe problem of untrusted devices and channels.(2) We  outline a security analysis to assess the envisaged performance ofthe proposed authentication protocol.(3) We report on  a  usability study that explores the viability of relyingon human computation in this context.

  • 314. Gutmann, Andreas
    et al.
    Renaud, Karen
    Volkamer, Melanie
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Nudging Bank Account Holders Towards More Secure PIN Management2015Ingår i: Journal of Internet Technology and Secured Transactions, ISSN 1748-569X, Vol. 4, s. 380-386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The memorability of PINs is an enduring security issue. This is especially pertinent in the context of banking, where technical systems evolve more slowly than in other contexts (e.g. many mobile phone operating systems have adopted alternative authentication mechanisms). Banking customers who struggle to memorise all their PINs often record them, sometimes insecurely, flying in the face of advice from their banks. Banks respond to memorisation difficulties by permitting customers to change their PINs. The reality is that both recording and changing unwittingly weakens the mechanism by increasing predictability. Yet trying to forbid these coping strategies is futile. It is far better to acknowledge the prevalence of such behaviours and to try to nudge people towards more secure PIN management. In this paper, we suggest a way of achieving this.

  • 315.
    Guzhva, Oksana
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Lärares kompetensutveckling och digitalisering av matematikundervisning: En enkätstudie om hur lågstadielärare kompetensutvecklar sig för att bemöta digitalisering av matematikundervisning2018Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med denna studie var att undersöka hur lågstadielärare fortbildade sig för att kunna möta de krav som ställs på dem vad det gäller digitalisering av matematikundervisning samt hur detta hänger samman med deras upplevda kompetens samt användning av IKT i matematikundervisningen.För att uppfylla syftet samlades studiens empiriska data in via en webbaserad enkätundersökning, som besvarades av 76 lågstadielärare.

    Resultatet visade att de flesta lågstadielärarna kompetensutvecklade sig på en mängd varierande sätt såväl på den formella arenan som på den informella arenan. Dessutom framkom det i resultatet att de lågstadielärare som fortbildade sig via webbaserade kompetensutvecklingssätt på den formella arenan i kombination med alla sätt på den informella arenan, högst uppskattade sina kunskaper inom delområdena TCK, TPK och TPACK samt använde IKT på flest sätt inom flest matematikområden. Vidare framkom det också att majoriteten av lågstadielärare fortbildade sig på alla sätt på båda arenor.Dessa lågstadielärare upplevde ha höga kunskaper i alla tre delområden, men deras IKT-användning låg på genomsnittsnivån för studiens samtliga kompetensutvecklingsformer.  

  • 316.
    Haglund, Kristoffer
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Qiu, Jia
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Documentation and implementation of interfaces for an embedded platform2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Using a new platform can be challenging, especially with relatively newly released platform and developer equipment. Difficulties and problems can arise during development from both hardware and software, some problems can be solved but sometimes help must be requested from the developers of the products.

    The consulting firm Altran in Karlstad has been dealing with this and has developed embedded software used in industrial welders for cars. There have been some uncertainty during their work, which has given birth to this project. The purpose of this project was to reconstruct and document Altran's initial development process, to make the process faster and easier for new developers. Besides the reconstruction, a discovery of unused features and components also became an important part of this project.

    The project has resulted in a documentation of various interfaces, an clock in system application called "Personnel Interactive Display and Educator", and a safe update application for the system.

  • 317.
    Haile, Habtegebreil Kassaye
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Rate Measurement Over Short Time Scales inStationary Cellular Receivers2019Ingår i: Proceedings of the 3rd Workshop on Mobile Network Measurement (MNM 2019), Paris, France, June 2019, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    An increasing number of cellular congestion controlalgorithms (CCAs) are relying on measurements of the deliveryrate observed at the receiver. Accordingly, early detection ofchanges in the receiver’s rate would improve the performanceof such algorithms. Rate measurements over short time intervalscould allow fast detection of change in the rate observed bythe upper layers of a cellular receiver. However, for cellularreceivers, upper-layer rate measurements over short time scalesproduce unreliable results due to the effect of underlying lowerlayer mechanisms such as scheduling and retransmissions. In thispaper, we introduce a rate estimation approach that reduces thevariability observed in short time scale receiver rate measurementsand allows faster rate change detection. We also integratean adaptive mechanism to improve online measurements overdifferent time scales.

  • 318.
    Haile, Habtegebreil Kassaye
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Rate Change Detection in Stationary Cellular Nodes2019Ingår i: Proceedings of the Fifteenth Swedish National Computer NetworkingWorkshop (SNCNW), Luleå, Sweden. 4-5 June, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    An increasing number of cellular congestion controlalgorithms (CCAs) are relying on measurements of the deliveryrate observed at the receiver. Accordingly, early detection ofchanges in the receiver’s rate would improve the performanceof such algorithms. Rate measurements over short time intervalscould allow fast detection of change in the rate observed bythe upper layers of a cellular receiver. However, upper layerrate measurements for cellular receivers over a short time scaleproduce unreliable results due to the effect of underlying lowerlayer mechanisms. In this paper, we introduce a rate estimationapproach that reduces the variability observed in short timescale receiver rate measurements and allows faster rate changedetection.

  • 319.
    Haile, Habtegebreil Kassaye
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Hurtig, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Atxutegi Narbona, Eneko
    University of the Basque Country.
    Liberal, Fidel
    University of the Basque Country.
    Arvidsson, Åke
    Kristianstad University.
    Evaluation of the Impact of TCP BBR Startup on CUBIC Traffic2018Ingår i: The Fourteenth Swedish National Computer Networking Workshop (SNCNW) 2018, 2018Konferensbidrag (Övrigt vetenskapligt)
  • 320.
    Halling, Sandra
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Identifiering av särbegåvade elever: Identifiering av generellt särbegåvade elever och särbegåvade elever inom ämnet matematik.2016Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Studiens syfte är att få ta del av pedagogernas syn på hur de ser på sin förmåga att identifiera särbegåvade elever och matematiskt särbegåvade elever. Om de tycker att de har goda förutsättningar för att kunna identifiera dessa elever eller om de upplever något hinder i sin förmåga att identifiera dem. Jag har valt att använda mig utav en enkätstudie för att få svar på mina frågor. Webbenkäten är skickad till 3 små kommuner och jag valde enkäter istället för intervjuer för att jag ville få en större spridning och fler olika sorters pedagoger som svarade.

    Studien visar att många av pedagogerna vet vad begreppet särbegåvad innebär men att de själva känner att de har för lite kunskap inom ämnet.

  • 321.
    Hannesdottir, Emma
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    mAPPematik: Matematiskt innehåll i surfplattors appar för barn i yngre åldrar2014Självständigt arbete på avancerad nivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Denna undersökning är gjord för att studera de appar som kan laddas ned och användas på surfplattor, då surfplattor blir ett mer vanligt förekommande pedagogiskt verktyg. Denna studie fokuserar på att granska appar som kan användas i matematikundervisningen för de yngre eleverna. Surfplattor köps in mer och mer till skolorna, då de är billiga och enkla verktyg att använda. Applikationerna som köps eller laddas ner till surfplattorna är billiga, lättillgängliga och utbudet är omfattande. Dock är utbildningsvetenskaplig forskning om surfplattor och dess applikationer inte så omfattande.

    I studien diskuteras vidare hur de matematikappar som granskats kan användas i matematikundervisningen kopplat till ett tydligt mål och syfte med användandet. De förmågor och centralt innehåll som studien fokuserar på är elevernas möjlighet att utveckla taluppfattning, likhetstecknets betydelse, räkne reglerna och tallinjen. Studien visar att alla de 13 appar som ingår i undersökningen kan användas i matematikundervisningen för färdighetsträning, men att bara 3 av apparna beskriver uppgifterna så pass utförligt att de kan användas redan från början i inlärningen.

  • 322.
    Hansen, Marit
    et al.
    Unabhängiges Landeszentrum für Datenschutz (ULD), Kiel, Germany.
    Kosta, EleniTilburg Institute for Law, Technology and Society (TILT), Tilburg University, Tilburg, The Netherlands.Nai-Fovino, IgorEuropean Commission - Joint Research Centre, Ispra, Italy.Fischer-Hübner, SimoneKarlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Privacy and Identity Management: The Smart Revolution2018Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    This book contains selected papers presented at the 12th IFIP WG 9.2, 9.5, 9.6/11.7, 11.6/SIG 9.2.2 International Summer School on Privacy and Identity Management, held in Ispra, Italy, in September 2017.The 12 revised full papers, 5 invited papers and 4 workshop papers included in this volume were carefully selected from a total of 48 submissions and were subject to a three-phase review process. The papers combine interdisciplinary approaches to bring together a host of perspectives: technical, legal, regulatory, socio-economic, social, societal, political, ethical, anthropological, philosophical, and psychological. They are organized in the following topical sections: privacy engineering; privacy in the era of the smart revolution; improving privacy and security in the era of smart environments; safeguarding personal data and mitigating risks; assistive robots; and mobility and privacy.

  • 323. Harrer, S.
    et al.
    Kopp, O.
    Lenhard, Jörg
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Patterns for workflow engine benchmarking2018Ingår i: ESOCC 2016: Advances in Service-Oriented and Cloud Computing / [ed] Barbosa, S.D.J., Filipe, J., Kotenko, I., Sivalingam, K.M., Washio, T., Yuan, J., Zhou, L., Springer , 2018, s. 151-163Konferensbidrag (Refereegranskat)
    Abstract [en]

    Workflow engines are frequently used in the service-oriented and cloud computing domains. Since engines have significant impact on the quality of service provided by hosted applications, it is desirable to compare and select the most appropriate engine for a given task. To enable such a comparison, approaches for benchmarking workflow engines have emerged. Although these approaches deal with different quality properties, such as performance or standard conformance, they face many reoccurring problems during the design and implementation phase, which they solve in similar ways. In this paper, we describe such common solutions to reoccurring problems in the area of workflow engine benchmarking as patterns. Our aim is to present pattern candidates that help benchmark authors to design and implement proper and valid workflow engine benchmarks and benchmarking tools

  • 324.
    Harrer, Simon
    et al.
    University of Bamberg.
    Kopp, Oliver
    University of Stuttgart.
    Lenhard, Jörg
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Patterns for workflow engine benchmarking2016Konferensbidrag (Refereegranskat)
  • 325.
    Harrer, Simon
    et al.
    University of Bamberg.
    Lenhard, Jörg
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstad University.
    Kopp, Oliver
    University of Stuttgart.
    Ferme, Vincenzo
    USI Lugano.
    Pautasso, Cesare
    USI Lugano.
    A Pattern Language for Workflow Engine Conformance and Performance Benchmarking2017Ingår i: Proceedings of the 22nd European Conference on Pattern Languages of Programs EuroPLoP '17, Association for Computing Machinery (ACM), 2017, artikel-id article No 1Konferensbidrag (Refereegranskat)
    Abstract [en]

    Workflow engines are frequently used in the domains of business process management, service orchestration, and cloud computing, where they serve as middleware platforms for integrated business applications. Engines have a significant impact on the quality of service provided by hosted applications. Therefore, it is desirable to compare them and to select the most appropriate engine for a given task. To enable such a comparison, approaches for benchmarking workflow engines have emerged. Although these approaches deal with different quality attributes, i.e., performance or standard conformance, they face many reoccurring design and implementation problems, which have been solved in similar ways. In this paper, we present a pattern language that captures such common solutions to reoccurring problems (e.g., from test identification, benchmarking procedure validation, automatic engine interaction, and workflow execution observation) in the area of workflow engine conformance and performance benchmarking. Our aim is to help future benchmark authors with the pattern language presented in this paper to benefit from our experience with the design and implementation of workflow engine benchmarks and benchmarking tools

  • 326. Hartswood, Mark
    et al.
    Jirotka, Marina
    Chenu-Abente, Ronald
    Hume, Alethia
    Giunchiglia, Fausto
    Martucci, Leonardo
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Fischer-Hübner, Simone
    Karlstads universitet, Institutionen för informationsteknologi.
    Privacy for Peer Profiling in Collective Adaptive Systems2015Ingår i: Privacy and Identity Management for the Future Internet in the Age of Globalisation: 9th IFIP WG 9.2, 9.5, 9.6/11.7, 11.4, 11.6/SIG 9.2.2 International Summer School, Patras, Greece, September 7-12, 2014, Revised Selected Papers / [ed] Jan Camenisch, Simone Fischer-Hübner, Marit Hansen, Cham: Springer, 2015, s. 237-252Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In this paper, we introduce a privacy-enhanced Peer Manager, which is a fundamental building block for the implementation of a privacy-preserving collective adaptive systems computing platform. The Peer Manager is a user-centered identity management platform that keeps information owned by a user private and is built upon an attribute-based privacy policy. Furthermore, this paper explores the ethical, privacy and social values aspects of collective adaptive systems and their extensive capacity to transform lives. We discuss the privacy, social and ethical issues around profiles and present their legal privacy requirements from the European legislation perspective.

  • 327.
    Hassan, Mahdi Mohammad
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Afzal, Wasif
    Mälardalen University.
    Blom, Martin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Lindström, Birgitta
    University of Skövde.
    Andler, Sten
    University of Skövde.
    Eldh, Sigrid
    Ericsson AB.
    Testability and Software Robustness: A Systematic Literature Review2015Ingår i: 2015 41st Euromicro Conference on Software Engineering and Advanced Applications, IEEE, 2015, s. 341-348Konferensbidrag (Refereegranskat)
    Abstract [en]

    The concept of software testability has been researched in several different dimensions, however the relation of this important concept with other quality attributes is a grey area where existing evidence is scattered. The objective of this study is to present a state-of-the-art with respect to issues of importance concerning software testability and an important quality attribute: software robustness. The objective is achieved by conducting a systematic literature review (SLR) on the topic. Our results show that a variety of testability issues are in focus with observability and controllability issues being most researched. Fault tolerance, exception handling and handling external influence are prominent robustness issues in focus.

  • 328.
    Hassan, Mahdi Mohammad
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Afzal, Wasif
    Lindström, Birgitta
    Shah, Syed Muhammad Ali
    Andler, Sten F.
    Blom, Martin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Testability and software performance: A systematic mapping study2016Ingår i: SAC '16 Proceedings of the 31st Annual ACM Symposium on Applied Computing, Association for Computing Machinery (ACM), 2016, s. 1566-1569Konferensbidrag (Refereegranskat)
    Abstract [en]

    In most of the research on software testability, functionalcorrectness of the software has been the focus while the ev-idence regarding testability and non-functional propertiessuch as performance is sporadic. The objective of this studyis to present the current state-of-the-art related to issuesof importance, types and domains of software under test,types of research, contribution types and design evaluationmethods concerning testability and software performance.We nd that observability, controllability and testing e ortare the main testability issues while timeliness and responsetime (i.e., time constraints) are the main performance issuesin focus. The primary studies in the area use diverse types ofsoftware under test within di erent domains, with real-timesystems as being a dominant domain. The researchers haveproposed many di erent methods in the area, however thesemethods lack implementation in practice as suggested byour gures for research type, contribution type and designevaluation methods.

  • 329.
    Hasselström, Nicklas
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Hjern, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Hoorn, Richard
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Hult, Marcus
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Häger, Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Syren, Jens
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Alfredsson, Stefan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Lindskog, Stefan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    The Design, Implementation, and Performance Evaluation of Secure Socket SCTP 2.02015Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The Stream Control Transmission Protocol (SCTP) is acomparatively new transport protocol that presents some advanced features compared to other standardized transport protocols. However, there are currently no standardized end-to-end security solutions suited for SCTP. One proposal for end-to-end encryption is the Secure Socket SCTP (S2-SCTP) protocol, developed by researchers at Karlstad University.  The security solution for SCTP described in this report uses key agreement for obtaining keys to be able to provide data confidentiality by encryption. The protocol is based on the S2-SCTP protocol, with smaller changes, and an overlaying management protocol has been designed and implemented. The management protocolis used to enable encryption and TLS authentication, to give a secure communication library over existing Berkeley Sockets. The performance evaluation of S2-SCTP compared to the already standardized end-to-endsecurity solutions, i.e., TLS over SCTP and DTLS over SCTP, shows that S2-SCTP achieves a higher throughput while still maintaining most of the advantages of SCTP.

  • 330.
    Hatamian, Majid
    et al.
    Goethe University Frankfurt, Frankfurt am Main, Germany.
    Kitkowska, Agnieszka
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Korunovska, Jana
    Vienna University of Business and Economics, Vienna, Austria.
    Kirrane, Sabrina
    Vienna University of Business and Economics, Vienna, Austria.
    “It’s shocking!": Analysing the impact and reactions to the A3: Android apps behaviour analyser2018Ingår i: Data and Applications Security and Privacy XXXII / [ed] Florian Kerschbaum, Stefano Paraboschi, Cham: Springer, 2018, s. 198-215Konferensbidrag (Refereegranskat)
    Abstract [en]

    The lack of privacy awareness in smartphone ecosystems prevents users from being able to compare apps in terms of privacy and from making informed privacy decisions. In this paper we analysed smartphone users’ privacy perceptions and concerns based on a novel privacy enhancing tool called Android Apps Behaviour Analyser (A3). The A3 tool enables user to behaviourally analyse the privacy aspects of their installed apps and notifies about potential privacy invasive activities. To examine the capabilities of A3 we designed a user study. We captured and contrasted privacy concern and perception of 52 participants, before and after using our tool. The results showed that A3 enables users to easily detect their smartphone app’s privacy violation activities. Further, we found that there is a significant difference between users’ privacy concern and expectation before and after using A3 and the majority of them were surprised to learn how often their installed apps access personal resources. Overall, we observed that the A3 tool was capable to influence the participants’ attitude towards protecting their privacy.

  • 331.
    Hatamian, Majid
    et al.
    Goethe University Frankfurt, Germany.
    Momen, Nurul
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Fritsch, Lothar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Rannenberg, Kai
    Goethe University Frankfurt, Germany.
    A Multilateral Privacy Impact Analysis Method for Android Apps2019Ingår i: Privacy Technologies and Policy / [ed] M. Naldi, G. F. Italiano, K. Rannenberg, M. Medina & A. Bourka, Cham: Springer, 2019, Vol. 11498, s. 87-106Konferensbidrag (Refereegranskat)
    Abstract [en]

    Smartphone apps have the power to monitor most of people’s private lives. Apps can permeate private spaces, access and map social relationships, monitor whereabouts and chart people’s activities in digital and/or real world. We are therefore interested in how much information a particular app can and intends to retrieve in a smartphone. Privacy-friendliness of smartphone apps is typically measured based on single-source analyses, which in turn, does not provide a comprehensive measurement regarding the actual privacy risks of apps. This paper presents a multi-source method for privacy analysis and data extraction transparency of Android apps. We describe how we generate several data sets derived from privacy policies, app manifestos, user reviews and actual app profiling at run time. To evaluate our method, we present results from a case study carried out on ten popular fitness and exercise apps. Our results revealed interesting differences concerning the potential privacy impact of apps, with some of the apps in the test set violating critical privacy principles. The result of the case study shows large differences that can help make relevant app choices.

  • 332. Hein, Patrick
    et al.
    Biswas, Debmalya
    Martucci, Leonardo
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Mühlhäuser, Max
    Technische Universität Darmstadt.
    Conflict Detection and Lifecycle Management for Access Control in Publish/Subscribe Systems2011Ingår i: High-Assurance Systems Engineering (HASE), 2011 IEEE 13th International Symposium on, IEEE Press, 2011, s. 104-111Konferensbidrag (Refereegranskat)
    Abstract [en]

    In today's collaborative business environment there is a need to share information across organizational boundaries. Publish/Subscribe systems are ideal for such scenarios as they allow real-time information to be shared in an asynchronous fashion. In this work, we focus on the access control aspect. While access control in general for publish/subscribe systems has been studied before, their usage in a multi-organizational scenario leads to some novel challenges. Here a publisher might wish to enforce restrictions w.r.t. not only subscribers, but also other publishers publishing certain event types due to competitive or regulatory reasons. With different publishers and subscribers having their own preferences and restrictions, conflicts are evident w.r.t. both publishing and subscribing to specific event types. Given this, the first contribution of this work is to provide efficient conflict detection and resolution algorithms. The other important (and often ignored) aspect of large scale and evolving systems is that of efficiently handling modifications to existing policies, e.g. a rule may become invalid after a certain period of time. Our approach in handling such modifications is two-fold: (i) to maintain consistency and (ii) to automatically detect and enforce rules which could not have been enforced earlier due to conflicts. The second contribution of our work is thus to provide lifecycle management for access control rules, which is tightly coupled with the conflict detection and resolution algorithms.

  • 333.
    Hellberg, Jesper
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Jönsson, Petter
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    FångstDataBanken: En administrativ webbplats för Sportfiskarna2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Föreningen Sportfiskarna samlar in statistik över fisket i Sverige för användning inom forskning och förvaltning. I och med lanseringen av applikationer för smarta telefoner har antalet inrapporterade fångster ökat och ett behov av att hantera data både till och från dessa applikationer har uppstått. Denna uppsats beskriver skapandet av Sportfiskarnas webbplats FångstDataBanken. Webbplatsens huvudsakliga syfte är att administrera informationen som finns tillgänglig i de mobila applikationerna men också att kunna hantera de inrapporterade fångsterna för statistiska ändamål.

    Projektets resultat är en webbplats skriven i ASP.NET MVC som tillfredsställer Sportfiskarnas behov. Webbplatsen utgör kärnan i Sportfiskarnas system för att hantera fångstrapportering och kommer att tas i bruk under sommaren 2015. 

  • 334.
    Hemdal, Tim
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Hellberg, Adam
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    EPIM Sync: Verifying information on inRiver and Episerver2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    When inRiver pushes to Episerver through a connector, there is no sure way to guarantee that all information is transferred without corruption. This project aims to create a service which pulls all product information from inRiver and Episerver and does a field by field comparison and creates a checksum for the values. The result of the comparison will be saved to a database and can be displayed graphically as a tree structure on a website. The project successfully achieved all the goals defined in the specification.

  • 335.
    Hemmi, Kirsti
    et al.
    Uppsala universitet, Åbo Akedemi University, Finland.
    Bråting, Kajsa
    Uppsala universitet.
    Liljekvist, Yvonne
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för humaniora och samhällsvetenskap (from 2013), Institutionen för pedagogiska studier (from 2013).
    Prytz, Johan
    Uppsala universitet.
    Madej, Lars
    Uppsala universitet.
    Pejlare, Johanna
    Chalmers University of Technology and the University of Gothenburg.
    Palm Kaplan, Kristina
    Uppsala universitet.
    Characterizing Swedish school algebra – initialfindings from analyses of steering documents,textbooks and teachers’ discourses2017Ingår i: Skrifter från Svensk förening för matematikdidaktisk forskning, ISSN 1651-3274, nr 12, s. 299-308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper reports the first results of an ongoing research project aiming atcharacterizing Swedish school algebra (grades 1-9). Both diachronic andsynchronic studies are conducted to identify the specific teaching traditiondeveloped in Sweden and different theoretical approaches are applied in theoverall project in order to obtain a rich picture of the Swedish case. The resultsreported here are based on the analyses of mathematics curriculum, textbooks andfocus group interviews with teachers in seven schools. The initial results indicatethat, since 1980s, algebra is vaguely addressed in the steering documents and theprogression of algebraic thinking is elusive in teachers’ discourses. We discuss theimplications of the initial findings for our project.

  • 336.
    Hemmi, Kirsti
    et al.
    Åbo Akademi University, Finland & Uppsala University, Sweden.
    Krzywacki, Heidi
    University of Helsinki, Finland & Mälardalen University, Sweden.
    Liljekvist, Yvonne
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Challenging traditional classroom practices: Swedish teachers’ interplay with Finnish curriculum materials2018Ingår i: Journal of Curriculum Studies, ISSN 0022-0272, E-ISSN 1366-5839, Vol. 51, nr 3, s. 1-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the current paper, we present an analysis of a case study in which we have followed Swedish primary teachers who voluntarily began using translated Finnish curriculum materials, i.e. a textbook and teacher guide, in order to reform their mathematics teaching. The multifaceted data, consisting of questionnaires, interviews, protocols from collegial meetings and classroom observations, were gathered during the period 2010–2014. The analysis of the interplay within this cross-cultural setting reveals the special characteristics and the challenges existing in practice. Both the experienced and inexperienced teachers offloaded a great deal of their agency to the materials in order to become familiar with the ideas they mediated. Yet, the lack of a clear rationale behind the organization of the materials, as well as the suggested activities connected to taken-for-granted features of the Finnish teaching tradition, made fruitful interaction problematic. The changes teachers made in their classroom practice were tightly connected to the support offered in the materials, without which the teachers abandoned their new classroom patterns. Based on the results of this study, we suggest a number of general aspects that we regard as important to consider when implementing curriculum materials developed within another cultural-educational context.

  • 337.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Alizadeh Noghani, Kyoomars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Kassler, Andreas
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Minimizing Live VM Migration Downtime Using OpenFlow based Resiliency Mechanisms2016Ingår i: Cloud Networking (Cloudnet), 2016 5th IEEE International Conference on, IEEE, 2016Konferensbidrag (Refereegranskat)
  • 338.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Alizadeh Noghani, Kyoomars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Kassler, Andreas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT.
    Dobrijevic, Ognjen
    University of Zagreb, Croatia.
    Jestin, Patrick
    Ericsson AB, Sweden.
    Policy-based routing and load balancing for EVPN-based data center interconnections2017Ingår i: Network Function Virtualization and Software Defined Networks (NFV-SDN), 2017 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), IEEE, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Ethernet VPN (EVPN) technology has emerged as a key solution for the interconnection of geo-distributed Data Centers (DCs) over provider-managed MPLS networks. Such interconnections need to satisfy service-level agreements, which can be achieved by enforcing Traffic Engineering (TE) policies. However, deploying an effective TE policy is challenging and complex. This stems from the fact that network administrators should have a detailed insight into the network status and protocol specifics. Software-Defined Networking (SDN) may facilitate both the policy definition and deployment based on its comprehensive network view and existing integration with DC management systems, such as OpenStack. This paper presents an SDN-based framework for policy-driven DC interconnections that are built around EVPN. The framework is designed to translate routing and other TE policies, which are defined for EVPN instances, into appropriate low-level network actions to meet the policy goals. A generic programming interface allows an SDN controller to load different TE strategies so as to implement the policy, without the need to hard-code it. Moreover, our evaluations illustrate how clients might benefit from specific TE strategies and what is their impact on network performance

  • 339.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Alizadeh Noghani, Kyoomars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Taheri, Javid
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    SDN implementations and protocols2018Ingår i: Big Data and Software Defined Networks / [ed] Javid Taheri, IET Digital Library, 2018, 1, s. 27-48Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This chapter begins by explaining the main SDN concepts with the focus on a SDN controller. It presents the most important aspects to consider when we desire to go from traditional network to a SDN networks. We present an in-depth analysis of the most commonly used and modern SDN controllers and analyse the main features, capabilities and requirements of one of the presented controllers. OpenFlow is the standard leading in the market allowing the management of the forwarding plane devices such as routers or switches. While there are other standards with the same aim, OpenFlow has secured a position in the market and has been expanded rapidly. Therefore, an analysis is presented on a different OpenFlow compatible device for the implementation of an SDN network. This study encompasses both software and hardware solutions along with the scope of implementation or use of these devices. This chapter ends up presenting a description of OpenFlow protocol alternatives, a more detailed description of OpenFlow and its components and other wellknown southbound protocols involved for the management and configuration of the devices.

  • 340.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Kassler, Andreas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Benson, T.
    Brown University, United States.
    Pongracz, G.
    Networking Research - Ericsson, United States.
    MP-HULA: Multipath transport aware load balancing using programmable data planes2018Ingår i: NetCompute 2018 - Proceedings of the 2018 Morning Workshop on In-Network Computing, Part of SIGCOMM 2018, Association for Computing Machinery, Inc , 2018, s. 7-13Konferensbidrag (Refereegranskat)
    Abstract [en]

    Datacenter networks ofer a large degree of multipath in order to provide large bisectional bandwidth. The end-to-end performance is determined by the load-balancing strategy which needs to be designed to efectively manage congestion. Consequently, congestion aware load-balancing strategies such as CONGA or HULA have been designed. Recently, more and more applications that are hosted on cloud servers use multipath transport protocols such as MPTCP. However, in the presence of MPTCP, existing load-balancing schemes including ECMP, HULA or CONGA may lead to suboptimal forwarding decisions where multiple MPTCP subfows of one connection are pinned on the same bottleneck link. In this paper, we present MP-HULA, a transport layer multi-path aware load-balancing scheme using Programmable Data Planes. First, instead of tracking congestion information for the best path towards the destination, each MP-HULA switch tracks congestion information for the best-k paths to a destination through the neighbor switches. Second, we design MP-HULA using Programmable Data Planes, where each leaf switch can identify, using P4, which MPTCP subfow belongs to which connection. MP-HULA then load-balances diferent MPTCP subfows of a MPTCP connection on diferent next hops considering congestion state while aggregating bandwidth. Our evaluation shows that MP-HULA with MPTCP outperforms HULA in average flow completion time (2.1x at 50% load, 1.7x at 80% load).

  • 341.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Kassler, Andreas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Zola, Enrica
    Univ Politecn Cataluna, C Jordi Girona 1-3, Barcelona, Spain..
    Predicting expected TCP throughput using genetic algorithm2016Ingår i: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 108, s. 307-322Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Predicting the expected throughput of TCP is important for several aspects such as e.g. determining handover criteria for future multihomed mobile nodes or determining the expected throughput of a given MPTCP subflow for load-balancing reasons. However, this is challenging due to time varying behavior of the underlying network characteristics. In this paper, we present a genetic-algorithm-based prediction model for estimating TCP throughput values. Our approach tries to find the best matching combination of mathematical functions that approximate a given time series that accounts for the TCP throughput samples using genetic algorithm. Based on collected historical datapoints about measured TCP throughput samples, our algorithm estimates expected throughput over time. We evaluate the quality of the prediction using different selection and diversity strategies for creating new chromosomes. Also, we explore the use of different fitness functions in order to evaluate the goodness of a chromosome. The goal is to show how different tuning on the genetic algorithm may have an impact on the prediction. Using extensive simulations over several TCP throughput traces, we find that the genetic algorithm successfully finds reasonable matching mathematical functions that allow to describe the TCP sampled throughput values with good fidelity. We also explore the effectiveness of predicting time series throughput samples for a given prediction horizon and estimate the prediction error and confidence. 

  • 342.
    Hernandez Benet, Cristian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Nasim, Robayet
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Alizadeh Noghani, Kyoomars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Kassler, Andreas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    OpenStackEmu - A Cloud Testbed Combining Network Emulation with OpenStack and SDN2017Ingår i: Consumer Communications & Networking Conference (CCNC), 2017 14th IEEE Annual, IEEE, 2017, s. 566-568Konferensbidrag (Refereegranskat)
    Abstract [en]

    OpenStack has been widely acknowledged to be one of the most important open source cloud platforms. In order to perform experimentally driven research in the area of cloud and cloud networking, there is however a big gap, because most researchers do not have access to a large cloud deployment and cannot change networking or compute infrastructure in order to test their algorithms and protocols on a large-scale. We developed OpenStackEmu, which is to the best of our knowledge the first attempt that combines OpenStack infrastructure with a Software Defined Networking (SDN) based controller such as OpenDaylight and a large-scale network emulator CORE (Common Open Research Emulator). The OpenStack compute and control nodes are connected to the CORE emulation server using TUN/TAP interfaces that inject the control (e.g. for VM migration) and data (VM-to-VM traffic) packets into a customizable network topology that is emulated using configurable Open vSwitches using CORE emulator. Experimenters can define e.g. fat-tree or distributed data center topologies and study the behavior of real VMs and services in those VMs under different background loads and SDN routing policies. We integrated the data center traffic generator DCT2Gen that allows to generate realistic background traffic based on traces from real data centers. Experimenters can study the performance impact of different VM migration strategies or different routing and load balancing schemes on real VM and application performance using different emulated topologies. We believe that OpenStackEmu is an important tool for both the SDN and OpenStack community in order to evaluate the performance of novel algorithms and protocols in the area of cloud networking.

  • 343.
    Herold, Sebastian
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Blom, Martin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Buckley, Jim
    University of Limerick / Lero, Ireland.
    Evidence in Architecture Degradation and Consistency Checking Research: Preliminary Results from a Literature Review2016Ingår i: Proceeding ECSAW '16 Proccedings of the 10th European Conference on Software Architecture Workshops, Association for Computing Machinery (ACM), 2016Konferensbidrag (Refereegranskat)
  • 344.
    Him-Jensen, Ida
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Sinnrik matematik: En läromedelsanalys med fokus på uppgifters visuella, auditiva och kinestetiska/taktila stöd2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The purpose of the essay is to examine the possibilities for students to learn mathematics with a variety of senses through the tasks in the teaching materials Nya matematikboken, Singma and Favorit matematik during school year 1. The focus is on visual, auditory and kinesthetic/tactile support. Furthermore, the aim is to investigate the different elements of the teaching material and the extent of the different support in them. With categories based on different sensory input, a thorough content analysis has been made to compare the three chosen teaching materials. The result shows that there are good grounds for learning through many senses. However, the support varies in total and in the different elements. Both similarities and differences have been distinguished. The results also clearly show the benefits of using the teaching materials fully.

  • 345.
    Honnér, Tina
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Var håller talfamiljer hus i läroboksuppgifter?: En läromedelsanalys av läroboksuppgifter i årskurs 1 som fokuserar på talfamiljer upp till 10, utifrån ett problemlösningsperspektiv.2017Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med studien är att åskådliggöra hur talfamiljer upp till 10 förekommer och gestaltas i läroboksuppgifter i årskurs 1, utifrån ett problemlösningsperspektiv. För att uppfylla syftet analyseras läroboksuppgifter med talfamiljer och delar av talfamiljer genom Cummins analysmodell där uppgifterna sorteras på fyra olika nivåer beroende av kontext och kognitiv svårighetsgrad efter att de kategoriserats. Resultatet blev både kvantitativt och kvalitativt där det framgick att läromedel tränar elever i talfamiljernas delar helt fristående. Ytterst få läromedel visade på talfamiljernas samband mellan talets helhet och delar. Den vanligaste läroboksuppgiften är en naken uppgift med addition eller subtraktion som räknas från vänster till höger helt utan stöd av kontext som bilder. Studien lyfter även tankar kring vad aktuell forskning säger kontra hur läroboksuppgifter är utformade och vad den enskilda läraren behöver tänka på när den ska göra sitt val av uppgifter till sina elever. 

  • 346.
    Hoseiny Farahabady, Mohammad Reza
    et al.
    Sch. of IT, Univ. of Sydney, Sydney, NSW, Australia.
    Taheri, Javid
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Tari, Zahir
    Sch. of Sci., RMIT Univ., Melbourne, VIC, Australia.
    Zomaya, Albert Y
    School of Information Technologies, University of Sydney.
    A Dynamic Resource Controller for a Lambda Architecture2017Ingår i: 2017 46th International Conference on Parallel Processing (ICPP), Piscataway: IEEE, 2017, s. 332-341Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lambda architecture is a novel event-driven serverless paradigm that allows companies to build scalable and reliable enterprise applications. As an attractive alternative to traditional service oriented architecture (SOA), Lambda architecture can be used in many use cases including BI tools, in-memory graph databases, OLAP, and streaming data processing. In practice, an important aim of Lambda's service providers is devising an efficient way to co-locate multiple Lambda functions with different attributes into a set of available computing resources. However, previous studies showed that consolidated workloads can compete fiercely for shared resources, resulting in severe performance variability/degradation. This paper proposes a resource allocation mechanism for a Lambda platform based on the model predictive control framework. Performance evaluation is carried out by comparing the proposed solution with multiple resource allocation heuristics, namely enhanced versions of spread and binpack, and best-effort approaches. Results confirm that the proposed controller increases the overall resource utilization by 37% on average and achieves a significant improvement in preventing QoS violation incidents compared to others.

  • 347.
    Hoseinyfarahabady, M. Reza
    et al.
    The University of Sydney, Australia.
    Bastani, Saeed
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Taheri, Javid
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Zomaya, Albert Y.
    The University of Sydney, Australia.
    Tari, Zahir
    RMIT University, Australia.
    Khan, Samee Ullah
    North Dakota State University, United States.
    Toward designing a dynamic CPU cap manager for timely dataflow platforms2018Ingår i: HPC '18 Proceedings of the High Performance Computing Symposium / [ed] Watson L.T., Thacker W.I., Sosonkina M., Rupp K., Weinbub J., Association for Computing Machinery (ACM), 2018, Vol. 50, nr 4, s. 60-70, artikel-id 6Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work, we propose a control-based solution for the problem of CPU resource allocation in data-flow platform that considers the degradation of performance caused by running concurrent data-flow processes. Our aim is to cut the QoS violation incidents for applications belonging to the highest QoS class. The performance of the proposed solution is bench-marked with the famous round robin algorithm. The experimental results confirms that the proposed algorithm can decrease the latency of processing data records for applications by 48% compared to the round robin policy.

  • 348.
    Huang, Peter
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Gagnero, Pontus
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Seamlessly Displaying Models in Virtual Reality2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 349.
    Hurtig, Per
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Alay, Ozgu
    Simula Research Laboratory.
    Ferlin, Simone
    Simula Research Laboratory.
    Yedugundla, Kiran
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    Reducing Transport Latency using Multipath Protocols2015Konferensbidrag (Refereegranskat)
  • 350.
    Hurtig, Per
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Alfredsson, Stefan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Brunström, Anna
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Evensen, Kristian
    Celerway Communications.
    Grinnemo, Karl-Johan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
    Fosselie Hansen, Audun
    Celerway Communications.
    Rozensztrauch, Tomasz
    Celerway Communications.
    A NEAT Approach to Mobile Communication2017Ingår i: MobiArch ’17 Proceedings of the Workshop on Mobility in the Evolving Internet Architecture, Association for Computing Machinery (ACM), 2017, s. 7-12Konferensbidrag (Refereegranskat)
    Abstract [en]

    The demands for mobile communication is ever increasing. Mobile applications are increasing both in numbers and in heterogeneity of their requirements, and an increasingly diverse set of mobile technologies are employed. This creates an urgent need for optimizing end-to-end services based on application requirements, conditions in the network and available transport solutions; something which is very hard to achieve with today's Internet architecture. In this paper, we introduce the NEAT transport architecture as a solution to this problem. NEAT is designed to offer a flexible and evolvable transport system, where applications communicate their transport-service requirements to the NEAT system in a generic, transport-protocol independent way. The best transport option is then configured at run time based on application requirements, network conditions, and available transport options. Through a set of real life mobile use case experiments, we demonstrate how applications with different properties and requirements could employ the NEAT system in multi-access environments, showing significant performance benefits as a result.

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