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  • 51.
    Almani, T.
    et al.
    Austin, USA.
    Kumar, Kundan
    University of Bergen, Norway.
    Singh, G.
    Austin, USA.
    Wheeler, M. F.
    Austin, USA.
    Stability of multirate explicit coupling of geomechanics with flow in a poroelastic medium2019In: Computers and Mathematics with Applications, ISSN 0898-1221, E-ISSN 1873-7668Article in journal (Refereed)
    Abstract [en]

    We consider single rate and multirate explicit schemes for the Biot system modeling coupled flow and geomechanics in a poro-elastic medium. These schemes are widely used in practice that follows a sequential procedure in which the flow and mechanics problems are fully decoupled. In such a scheme, the flow problem is solved first with time-lagging the displacement term followed by the mechanics solve. The multirate explicit coupling scheme exploits the different time scales for the mechanics and flow problems by taking multiple finer time steps for flow within one coarse mechanics time step. We provide fully discrete schemes for both the single and multirate approaches that use Backward Euler time discretization and mixed spaces for flow and conformal Galerkin for mechanics. We perform a rigorous stability analysis and derive the conditions on reservoir parameters and the number of finer flow solves to ensure stability for both schemes. Furthermore, we investigate the computational time savings for explicit coupling schemes against iterative coupling schemes.

  • 52.
    Almgren, Mats
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Hansen, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Coridendro: Ett verktyg för att grafiskt åskådliggöra incidensen av malignt melanom inom olika släkter2006Independent thesis Basic level (professional degree), 10 points / 15 hpStudent thesis
    Abstract [en]

    The county council of Värmland is taking part in a larger project which in general consists of surveying malign melanoma within different families. Counties in Sweden are following-up on patients suffering from malign melanoma, which is likely to have inheritable causes. When a suspected heritable malign melanoma is found an investigation is started. A pedigree is drawn, describing the propositus’ family.

    Every individual in the pedigree is represented by a symbol. The appearance of this symbol is determined by: unhealthy/healthy, diseased/alive, man/woman. When the individuals have been identified and the according symbols drawn, the symbols are connected by lines representing kinship.

    Today the pedigrees are drawn by hand using pen and paper. This is a time consuming task and the appearance differ depending on who is drawing the pedigree.

    The result of our problem-analysis is a graphical software tool. On a drawing area the user may draw the symbols on predefined locations. The tool also allows for symbols to be connected with lines. Symbols are connected through selecting a start-symbol and an end-symbol.

  • 53.
    Alsharoa, A.
    et al.
    University of Central Florida.
    Ghazzai, Hakim
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Yuksel, M.
    University of Central Florida.
    Kadri, A.
    Qatar Mobility Innovations Center (QMIC), Qatar University.
    Kamal, A. E.
    Iowa State University (ISU), Ames.
    Trajectory optimization for multiple UAVs acting as wireless relays2018In: 2018 IEEE International Conference on Communications Workshops, ICC Workshops 2018 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 1-6Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel wireless relay selection scheme involving multiple mobile Unmanned Aerial Vehicles (UAVs) to support communicating ground users. The goal is to optimize the transmit power levels and trajectories of the relaying UAVs in order to maximize the data rate transmission of the ground users which are suffering from the absence of direct link. Assuming that each UAV is initially characterized by a predefined trajectory for a primary task, we propose to modify it whenever it is needed and the energy and trajectory boundaries constraints allow. We propose to solve this problem using an iterative two steps solution; first, a Mixed Integer Linear Programming (MILP) problem is formulated to optimally determine the users- UAVs associations and the UAVs' corresponding transmit power levels. In the second step, an efficient algorithm based on a recursive shrink-and-realign process is proposed to optimize the UAV trajectories. The performance of the proposed method shows advantages in terms of average throughput compared to the predefined trajectories solution.

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

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



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



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

  • 55. Andersson, Christer
    Design and Evaluation of anonymity Solutions for Mobile Networks2008Doctoral thesis, monograph (Other academic)
  • 56.
    Andersson, Christer
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Design and Evaluation of Anonymity Solutions for Mobile Networks2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Internet and mobile communications have had a profound effect on today's society. New services are constantly being deployed, in which personal data are being processed in return for personally tailored services. While mobile networks lay the groundwork for new innovative services, at the same time they pose numerous privacy challenges. There is the risk that honest citizens participating in mobile communications will have their privacy invaded for "the greater good". We argue that it is highly important that individuals are empowered to retain control over their personal spheres. Thus, the goal of this thesis is to design and evaluate anonymous overlay networks} adapted for mobile networks that allow users to control which information leaves their personal spheres in a mobile communication.

    Technically, by using an anonymous overlay network, users can communicate with their communication partners without disclosing their network identities. In this thesis, we propose three different anonymous overlay networks tailored for mobile networks. First, two approaches are proposed for anonymous browsing on the mobile Internet, namely mCrowds and a Tor-based approach. By applying theoretical analysis and\,/\,or practical experiments, we show that these approaches offer an appropriate trade-off between the offered degree of anonymity and performance loss. Second, an anonymous overlay network for use in mobile ad hoc networks - Chameleon - is suggested.

    Besides the actual design of these anonymous overlay networks, this thesis provides novel contributions in other essential areas of privacy protection and anonymous communication. First, also non-technical aspects of privacy protection are thoroughly discussed, including legal, social, and user interface aspects. Second, we survey existing metrics for quantifying anonymity and also propose new ideas regarding anonymity metrics. Third, we review and classify existing mechanisms for anonymous communication in mobile ad hoc networks. Lastly, we also propose a cryptographic technique for building up the user base of an anonymous overlay network in a secure and privacy-friendly manner.

  • 57.
    Andersson, Christer
    Karlstad University, Division for Information Technology.
    Enhancing Privacy for Mobile Networks: Examples of Anonymity Solutions and Their Analysis2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Internet and mobile communications have had a profound effect on today’s society. New services are constantly being deployed, in which an increasing amount of personal data is being processed in return for personally tailored services. Further, the use of electronic surveillance is increasing. There is the risk that honest citizens will have their privacy invaded for “the greater good”. We argue that it is of uttermost importance to retain the individuals’ control over their personal spheres.

    One approach for enhancing the users’ privacy is to deploy technical measures for safeguarding privacy, so-called Privacy-Enhancing Technologies (PETs). This thesis examines a set of PETs for enabling anonymous communication, so-called anonymous overlay networks,which eliminate the processing of personal data altogether by allowing the users act anonymously when communicating in a networked environment.

    This thesis focuses mainly on mobile networks. These are of great interest because on the one hand they lay the groundwork for new innovative applications, but on the other hand they pose numerous novel challenges to privacy. This thesis describes the implementation

    and performance evaluation of mCrowds – an anonymous overlay network for mobile Internet that enables anonymous browsing. It also describes the ongoing investigation on how to design anonymous overlay networks in order to make them suitable for mobile ad hoc

    networks, a required building block for ambient intelligence.

  • 58. Andersson, Christer
    Enhancing Privacy in Mobile Networks: Anonymity Solutions and Their Analysis2005Licentiate thesis, monograph (Other academic)
  • 59.
    Andersson, Christer
    et al.
    Karlstad University, Division for Information Technology.
    Camenisch, Jan
    IBM Zurich Research Laboratory, Switzerland.
    Crane, Stephen
    Hewlett-Packard Laboratories, UK.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    Leenes, Ronald
    Tilburg University, the Netherlands.
    Pearson, Siani
    Hewlett-Packard Laboratories, UK.
    Pettersson, John Sören
    Karlstad University, Division for Information Technology.
    Sommer, Dieter
    IBM Zurich Research Laboratory, Switzerland.
    Trust in PRIME2005In: Proceedings of the 5th IEEE International Symposium on Signal Processing and IT, IEEE conference proceedings, 2005, p. 552-559Conference paper (Other academic)
    Abstract [en]

    The PRIME project develops privacy enhancing identity management systems that allow users in various application areas such as e-commerce to regain control over their personal spheres. This paper introduces the PRIME technical architecture that also includes special trust-enhancing mechanisms, and shows how PRIME technologies can enhance privacy and trust of e-shopping customers. It also discusses the socio-psychological factors and HCI aspects influencing the end user's trust in privacy enhancing identity management, and shows why HCI research, user studies, and socio-psychological research, are necessary efforts to accompany system design.

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

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

  • 61.
    Andersson, Christer
    et al.
    Karlstad University, Division for Information Technology.
    Fischer-Huebner, Simone
    Karlstad University, Division for Information Technology.
    Lundin, Reine
    Karlstad University, Division for Information Technology.
    Enabling Anonymity for the Mobile Internet Using the mCrowds System2003In: Risk and Challenges of the Network Society: Proceedings of the IFIP WG 9.2, 9.6/11.7 Summer School 4-8 August 2003. / [ed] Penny Duquennoy, Simone Fischer-Hübner, Jan Holvast & Albin Zuccato, Karlstad: Karlstads universitet , 2003Conference paper (Refereed)
  • 62.
    Andersson, Christer
    et al.
    Karlstad University, Division for Information Technology.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Lundin, Reine
    Karlstad University, Division for Information Technology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    mCrowds: Anonymity for the Mobile Internet2003In: HumanIT 2003, Karlstad: Karlstad University Press, 2003, p. 79-92Chapter in book (Refereed)
  • 63. Andersson, Christer
    et al.
    Kohlweiss, Markulf
    Martucci, Leonardo
    Panchenko, Andryi
    A Self-Certified and Sybil-Free Framework for Secure Digital Identity Domain Buildup2008Conference paper (Refereed)
    Abstract [en]

    An attacker who can control arbitrarily many user identities can break the security properties of most conceivable systems. This is called a Sybil attack. We present a solution to this problem that does

    not require online communication with a trusted third party and that in addition preserves the privacy of honest users. Given an initial so-called Sybil-free identity domain, our proposal can be used for deriving Sybil-free unlinkable pseudonyms associated with other identity domains. The pseudonyms are self-certified and computed by the users themselves from their cryptographic long-term identities

  • 64. Andersson, Christer
    et al.
    Lundin, Reine
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    On the Fundamentals of Anonymity Metrics2007In: The Future of Identity in the Information Society: Proceedings of the Third IFIP WG 9.2, 9.6/ 11.6, 11.7/FIDIS International Summer School on The Future of Identity in the Information Society / [ed] Simone Fischer-Hübner, Penny Duquenoy, Albin Zuccato and Leonardo Martucci, 2007Conference paper (Refereed)
  • 65. Andersson, Christer
    et al.
    Lundin, Reine
    On the Fundamentals of Anonymity Metrics2008In: The Future of Identity in the Information Society: Proceedings of the Third IFIP WG 9.2, 9.6/ 11.6, 11.7/FIDIS International Summer School on The Future of Identity in the Information Society, Karlstad University, Sweden, August 4-10 2007 / [ed] Simone Fischer-Hübner, Penny Duquenoy, Albin Zuccato and Leonardo Martucci, Springer-Verlag New York, 2008, p. 325-341Chapter in book (Refereed)
  • 66.
    Andersson, Christer
    et al.
    Karlstad University, Division for Information Technology.
    Lundin, Reine
    Karlstad University, Division for Information Technology.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    Privacy-Enhanced WAP Browsing with mCrowds: Anonymity Properties and Performance Evaluation of the mCrowds System2004Conference paper (Refereed)
  • 67.
    Andersson, Christer
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Martucci, Leonardo A.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Privacy & Anonymity in Mobile Ad Hoc Networks2008In: Handbook of Research on Wireless Security / [ed] Yan Zhang, Jun Zheng & Miao Ma, IGI Global , 2008Chapter in book (Other academic)
  • 68. Andersson, Christer
    et al.
    Martucci, Leonardo A.
    Fischer-Hübner, Simone
    Requirements for Privacy in Mobile Ad Hoc Networks2005Conference paper (Refereed)
  • 69. Andersson, Christer
    et al.
    Martucci, Leonardo
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Privacy and Anonymity in Mobile Ad Hoc Networks2008In: Mobile Computing: Concepts, Methodologies, Tools, and Applications / [ed] David Taniar, Information Science Reference , 2008Chapter in book (Refereed)
  • 70. Andersson, Christer
    et al.
    Martucci, Leonardo
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Privacy Requirements for Mobile Ad Hoc Networks2005Conference paper (Refereed)
  • 71.
    Andersson, David
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Teoretisk och praktisk genomgång av IPv6 och dess säkerhetsaspekter2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

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

     

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

  • 72.
    Andersson, Henrik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Oreland, Peter
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    City Mobility Model with Google Earth Visualization2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    Mobile Ad Hoc Networks are flexible, self configuring networks that do not need a fixed infrastructure. When these nets are simulated, mobility models can be used to specify node movements. The work in this thesis focuses on designing an extension of the random trip

    mobility model on a city section from EPFL (Swiss federal institute of technology). Road data is extracted from the census TIGER database, displayed in Google Earth and used as input for the model. This model produces output that can be used in the open source network simulator ns-2.

    We created utilities that take output from a database of US counties, the TIGER database, and convert it to KML. KML is an XML based format used by Google Earth to store geographical data, so that it can be viewed in Google Earth. This data will then be used as input to the modified mobility model and finally run through the ns-2 simulator. We present some NAM traces, a network animator that will show node movements over time.

    We managed to complete most of the goals we set out, apart from being able to modify node positions in Google Earth. This was skipped because the model we modified had an initialization phase that made node positions random regardless of initial position. We were also asked to add the ability to set stationary nodes in Google Earth; this was not added due to time constraints.

  • 73.
    Andersson, Jan-Olof
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Larsson, Samuel
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Tobias, Sjöholm
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Implementation of the NEAT Policy Manager2019Report (Refereed)
    Abstract [en]

    The NEAT system was developed in 2017 to increase flexibility in the choice of network transport protocol being used. One of the most important components of the NEAT system is the Policy Manager (PM), which determines what protocol is to be utilized by the application. The PM is written in Python while the rest of the NEAT system is C-based, so a natural evolution of the PM is to perform a functional translation of it to C. While the main goal was solely to develop a fully functional C-based PM, the difference in programming languages in the end also brought a performance increase of 28 times compared with the Python-based PM. There are still a few improvements left to do in the PM, but it is already a notable improvement for the NEAT system as a whole.

  • 74.
    Andersson, Kerstin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Exact Probability Distribution versus Entropy2014In: Entropy, ISSN 1099-4300, E-ISSN 1099-4300, Vol. 16, no 10, p. 5198-5210Article in journal (Refereed)
    Abstract [en]

    The problem addressed concerns the determination of the average numberof successive attempts of guessing a word of a certain length consisting of letters withgiven probabilities of occurrence. Both first- and second-order approximations to a naturallanguage are considered. The guessing strategy used is guessing words in decreasing orderof probability. When word and alphabet sizes are large, approximations are necessary inorder to estimate the number of guesses. Several kinds of approximations are discusseddemonstrating moderate requirements regarding both memory and central processing unit(CPU) time. When considering realistic sizes of alphabets and words (100), the numberof guesses can be estimated within minutes with reasonable accuracy (a few percent) andmay therefore constitute an alternative to, e.g., various entropy expressions. For manyprobability distributions, the density of the logarithm of probability products is close to anormal distribution. For those cases, it is possible to derive an analytical expression for theaverage number of guesses. The proportion of guesses needed on average compared to thetotal number decreases almost exponentially with the word length. The leading term in anasymptotic expansion can be used to estimate the number of guesses for large word lengths.Comparisons with analytical lower bounds and entropy expressions are also provided.

  • 75.
    Andersson, Mikael
    et al.
    Karlstad University, Division for Information Technology.
    Nykvist, Conny
    Karlstad University, Division for Information Technology.
    Utökning av PHP2006Independent thesis Basic level (professional degree), 10 points / 15 hpStudent thesis
    Abstract [en]

    This bachelor’s report is based upon an assignment specified by the company IT Resource AB, located in Årjäng Värmland.

    The goal of this bachelor’s project was to create an API to extend the functionality of PHP. The API shall simplify and make the work more efficient for IT Resource AB when developing web applications. The simplification and the increased efficiency that the API offers are the possibilities to reuse and easily add new functions to the API when needed.

    The functionality that the API will offer is an enhanced capability to handle variables and strings generated from a web page written in PHP. The enhanced capability refers to the possibility to store variables and strings from a web page written in PHP.

    The API created consists of 2 parts, a client and a server. The client in the client/server system is an external module which contains the functionality for the communication with both PHP and the server. This means that the client in the client/server system will act as an interface between PHP and the server.

    The implementation of the API’s functionality is found in the server part of the client/server system. The functionality implemented in the server is the possibility to store variables and strings in the main memory.

    The result of this project is an API that increases the functionality of PHP. The API can, when needed, be extended further, and IT Resource AB can benefit from using it when developing web applications that make use of PHP.

  • 76.
    Andersson, Ricky
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Classification of Video Traffic: An Evaluation of Video Traffic Classification using Random Forests and Gradient Boosted Trees2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Traffic classification is important for Internet providers and other organizations to solve some critical network management problems.The most common methods for traffic classification is Deep Packet Inspection (DPI) and port based classification. These methods are starting to become obsolete as more and more traffic are being encrypted and applications are starting to use dynamic ports and ports of other popular applications. An alternative method for traffic classification uses Machine Learning (ML).This ML method uses statistical features of network traffic flows, which solves the fundamental problems of DPI and port based classification for encrypted flows.The data used in this study is divided into video and non-video traffic flows and the goal of the study is to create a model which can classify video flows accurately in real-time.Previous studies found tree-based algorithms to work well in classifying network traffic. In this study random forest and gradient boosted trees are examined and compared as they are two of the best performing tree-based classification models.Random forest was found to work the best as the classification speed was significantly faster than gradient boosted trees. Over 93% correctly classified flows were achieved while keeping the random forest model small enough to keep fast classification speeds.

  • 77.
    Angulo, Julio
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Usable privacy for digital transactions: Exploring the usability aspects of three privacy enhancing mechanisms2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The amount of personal identifiable information that people distribute over different online services has grown rapidly and considerably over the last decades. This has led to increased probabilities for identity theft, profiling and linkability attacks, which can in turn not only result in a threat to people’s personal dignity, finances, and many other aspects of their lives, but also to societies in general. Methods and tools for securing people’s online activities and protecting their privacy on the Internet, so called Privacy Enhancing Technologies (PETs), are being designed and developed. However, these technologies are often seen by ordinary users as complicated and disruptive of their primary tasks.

     

    In this licentiate thesis, I investigate the usability aspects of three main privacy and security enhancing mechanisms. These mechanisms have the goal of helping and encouraging users to protect their privacy on the Internet as they engage in some of the steps necessary to complete a digital transaction. The three mechanisms, which have been investigated within the scope of different research projects, comprise of (1) graphical visualizations of service providers’ privacy policies and user-friendly management and matching of users’ privacy preferences “on the fly”, (2) methods for helping users create appropriate mental models of the data minimization property of anonymous credentials, and (3) employing touch-screen biometrics as a method to authenticate users into mobile devices and verify their identities during a digital transaction.

     

    Results from these investigations suggest that these mechanisms can make digital transactions privacy-friendly and secure while at the same time delivering convenience and usability for ordinary users.

  • 78.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Pulls, Tobias
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Wästlund, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology.
    Towards Usable Privacy Policy Display & Management2012In: Information Management & Computer Security, ISSN 0968-5227, Vol. 20, p. 4-17Article in journal (Refereed)
    Abstract [en]

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

  • 79.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Wästlund, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology.
    Exploring Touch-Screen Biometrics for User Identification on Smart Phones2011In: Privacy and Identity Managementfor Life: Proceedings of the 7th IFIP WG 9.2, 9.6/11.7, 11.4, 11.6 International Summer School 2011 / [ed] an Camenisch, Bruno Crispo, Simone Fischer-Hübner, Ronald Leenes, and Giovanni Russello, Springer, 2011, p. 130-143Conference paper (Refereed)
    Abstract [en]

    The use of mobile smart devices for storing sensitive informationand accessing online services is increasing. At the same time, methods for authenticating users into their devices and online services that are not only secure, but also privacy and user-friendly are needed. In this paper, we present our initial explorations of the use of lock pattern dynamics as a secure and user-friendly two-factor authentication method. We developed an application for the Android mobile platform to collect data on the way individuals draw lock patterns on a touchscreen. Using a Random Forest machine learning classier this method achieves an average Equal Error Rate (EER) of approximately 10.39%, meaning that lock patterns biometrics can be used for identifying users towards their device, but could also pose a threat to privacy if the users' biometric information is handled outside their control.

  • 80.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Centre for HumanIT. Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Karlstad Business School.
    Wästlund, Erik
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Social and Psychological Studies.
    Profiles: prototyping an online information segregation service2013In: Human-Computer Interaction: Users and Contexts of Use, volume 8006, Proceedings Part III, / [ed] Kurosu, M.,, Springer, 2013Conference paper (Refereed)
  • 81.
    Angulo, Julio
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Wästlund, Erik
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology.
    Gullberg, Peter
    Gemalto, Gothenburg.
    Kling, Daniel
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management.
    Tavemark, Daniel
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Information Systems and Project Management.
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    Understanding the user experience of secure mobile online transactions in realistic contexts of use2012In: Symposium on Usable Privacy and Security (SOUPS) 2012, Washington D.C.,USA: ACM Digital Library, 2012, p. 8-Conference paper (Refereed)
    Abstract [en]

    Possible attacks on mobile smart devices demand higher security for applications handling payments or sensitive information. The introduction of a tamper-proof area on future generations of mobile devices, called Trusted Execution Environment (TEE), is being implemented. Before devices with embedded TEEs can be deployed to the public, investigations on usability aspects of Trusted User Interfaces (TUI) are needed. This article describes the process we have followed at gathering requirements, prototyping and testing suitable designs for TUIs in combination with a touch-screen biometric system. At the end, we present relevant findings of a pilot study that we have conducted using an Experience Sampling Method (ESM) as part of our ongoing work.

  • 82.
    Arvidsson, Andreas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Andreasson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Distributed computing for the public transit domain2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 83.
    Arvidsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Utvärdering av containerbaserad virtualisering för telekomsignalering2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    New and innovative technologies to improve the techniques that are already being used are constantly developing. This project was about evaluating if containers could be something for the IT company Tieto to use on their products in telecommunications. Container are portable, standalone, executable lightweight packages of software that also contains all it needs to run the software. Containers are a very hot topic right now and are a fast-growing technology. Tieto wanted an investigation of the technology and it would be carried out with certain requirements where the main requirement was to have a working and executable protocol stack in a container environment. In the investigation, a proof of concept was developed, proof of concept is a realization of a certain method or idea in order to demonstrate its feasibility. The proof of concept led to Tieto wanting additional experiments carried out on containers. The experiments investigated if equal performance could be achieved with containers compared to the method with virtual machine used by Tieto today. The experiment observed a small performance reduction of efficiency, but it also showed benefits such as higher flexibility. Further development of the container method could provide a just as good and equitable solution. The project can therefore be seen as successful whereas the proof of concept developed, and experiments carried out both points to that this new technology will be part of Tieto's product development in the future.

  • 84. Aspinall, David
    et al.
    Camenisch, Jan
    Hansen, Marit
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    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 School2016Book (Refereed)
  • 85.
    Asplund, Katarina
    Karlstad University, Division for Information Technology.
    Implementation and Experimental Evaluation of a Partially Reliable Transport Protocol2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the last decade, we have seen an explosive growth in the deployment of multimedia applications on the Internet. However, the transport service provided over the Internet is not always feasible for these applications, since the network was originally designed for other types of applications. One way to better accommodate the service requirements of some of these applications is to provide a partially reliable transport service. A partially reliable transport service does not insist on recovering all, but just some of the packet losses, thus providing a lower transport delay than a reliable transport service. The work in this thesis focuses on the design, implementation, and evaluation of a partially reliable transport protocol called PRTP. PRTP has been designed as an extension to TCP in order to show that such a service could be effectively integrated with current protocol standards. An important feature of PRTP is that all modifications for PRTP are restricted to the receiver side, which means that it could be very easily deployed. The thesis presents performance results from various experiments on a Linux implementation of PRTP. The results suggest that transfer times can be decreased significantly when using PRTP as opposed to TCP in networks in which packet loss occurs. Furthermore, the thesis includes a study that investigates how users perceive an application that is based on a partially reliable service. Specifically, how users select the trade-off between image quality and latency when they download Web pages is explored. The results indicate that many of the users in the study could accept less than perfect image quality

    if the latency could be shortened.

  • 86.
    Asplund, Katarina
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Implementation and Experimental Evaluation of aPartially Reliable Transport Protocol2004Licentiate thesis, monograph (Other academic)
    Abstract [en]

    In the last decade, we have seen an explosive growth in the deployment of multimedia applications on the Internet. However, the transport service provided over the Internet is not always feasible for these applications, since the network was originally designed for other types of applications. One way to better accommodate the service requirements of some of these applications is to provide a partially reliable transport service. A partially reliable transport service does not insist on recovering all, but just some of the packet losses, thus providing a lower transport delay than a reliable transport service. The work in this thesis focuses on the design, implementation, and evaluation of a partially reliable transport protocol called PRTP. PRTP has been designed as an extension to TCP in order to show that such a service could be effectively integrated with current protocol standards. An important feature of

    PRTP is that all modifications for PRTP are restricted to the receiver side, which means that it could be very easily deployed. The thesis presents performance results from various experiments on a Linux implementation of PRTP. The results suggest that transfer times can be decreased significantly when using PRTP as opposed to TCP in networks in which packet loss occurs. Furthermore, the thesis includes a study that investigates how users perceive an application that is based on a partially reliable service. Specifically, how users select the trade-off between image quality and latency when they download Web pages is explored. The results indicate that many of the users in the study could accept less than perfect image quality if the latency could be shortened.

  • 87.
    Asplund, Katarina
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    An Evaluation of User Web Service Requirements2002Conference paper (Refereed)
  • 88.
    Asplund, Katarina
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Partially Reliable Multimedia Transport2004Report (Other academic)
    Abstract [en]

    The ongoing deployment of applications that transmit multimedia data makes it important for the Internet to better accommodate the service requirements of this type of applications. One approach is to provide a partially reliable service, i.e. a service that does not insist on recovering all but only some of the packet losses, thus providing less delay than a reliable transport service. This technical report describes a transport protocol that provides a partially reliable service. The protocol, called PRTP, is especially aimed at applications with soft real-time requirements. The report also presents performance results from a number of different experiments investigating different aspects of PRTP. The results indicate that transfer times can be significantly decreased when using PRTP as opposed to TCP when packets are lost in the network.

  • 89.
    Asplund, Katarina
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    The QoS Trade-off Between Latency and Image Quality on the Web: A User Perspective2002Conference paper (Refereed)
  • 90.
    Asplund, Katarina
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    The Trade-off Between Latency and Image Quality on the Web: A User Perspective2003In: / [ed] John Sören Pettersson, 2003Chapter in book (Other academic)
  • 91.
    Asplund, Katarina
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Garcia, Johan
    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.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Schneyer, S.
    Decreasing Transfer Delay Through Partial Reliability2000Conference paper (Refereed)
  • 92.
    Avallone, Stefano
    et al.
    Univ Naples Federico II, Dept Comp Engn, I-80125 Naples, Italy.
    Di Stasi, Giovanni
    Univ Naples Federico II, Dept Comp Engn, I-80125 Naples, Italy.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    A Traffic-Aware Channel and Rate Re-Assignment Algorithm for Wireless Mesh Networks.2013In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 12, no 7, p. 1335-1348Article in journal (Refereed)
  • 93.
    Axelsson, Therese
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Melani, Daniel
    Karlstad University, Faculty of Economic Sciences, Communication and IT.
    Hash Comparison Module for OCFA2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Child abuse content on the Internet is today an increasing problem and difficult to dealwith. The techniques used by paedophiles are getting more sophisticated which means ittakes more effort of the law enforcement to locate this content.

    To help solving this issue, a EU-funded project named FIVES is developing a set oftools to help investigations involving large amounts of image and video material. One ofthese tools aims to help identifying potentially illegal files by hash signatures derived fromusing classification information from another project.

  • 94.
    Bajpai, Vaibhav
    et al.
    Technical University of Munich, Germany.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Feldmann, Anja
    Max Planck Society, Germany.
    Kellerer, Wolfgang
    Technical University of Munich, Germany.
    Pras, Aiko
    University of Twente, Netherlands .
    Schulzrinne, Henning
    Columbia University, USA.
    Smaragdakis, Georgios
    Technical University of Berlin, Germany.
    Waehlisch, Matthias
    Free University of Berlin, Germany.
    Wehrle, Klaus
    RWTH Aachen University, Germany .
    The Dagstuhl Beginners Guide to Reproducibility for Experimental Networking Research2019In: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 49, no 1, p. 24-30Article in journal (Other academic)
    Abstract [en]

    Reproducibility is one of the key characteristics of good science, but hard to achieve for experimental disciplines like Internet measurements and networked systems. This guide provides advice to researchers, particularly those new to the field, on designing experiments so that their work is more likely to be reproducible and to serve as a foundation for follow-on work by others.

  • 95.
    Bakar, Sakhinah Abu
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Characterization of essential proteins based on network topology in proteins interaction networks2014In: Proceedings of the 3rd International Conference on Mathematical Sciences, American Institute of Physics (AIP), 2014, Vol. 1602, p. 36-42Conference paper (Refereed)
  • 96.
    Bakar, Sakhinah Abu
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    FIS-PNN: A Hybrid Computational Method for Protein-Protein Interactions Prediction Using the Secondary Structure Information2011In: IEEE/ACS International Conference on Computer Systems and Applications (AICCSA-2011), IEEE conference proceedings, 2011Conference paper (Refereed)
  • 97.
    Bakar, Sakhinah Abu
    et al.
    The University of Sydney, Australia.
    Taheri, Javid
    The University of Sydney, Australia.
    Zomaya, Albert
    The University of Sydney, Sydney, Australia.
    Identifying Hub Proteins and Their Essentiality from Protein-protein Interaction Network2011In: Bioinformatics and Bioengineering (BIBE), 2011 IEEE 11th International Conference on, Taichung, Taiwan: IEEE Press, 2011Conference paper (Refereed)
  • 98.
    Baktirovic, Adnan
    Karlstad University, Division for Information Technology.
    Utveckling av hotspotsystem2008Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    This graduation work was done as a assignment from Fiber Optic City company based in Hudiksvall Sweden. The base assignment was to create an automated payment system for a Hotspot network and a company web page. The hotspot system should work as a standalone service. The company has already a working free-of-charge service that is offered to its customers and is based on Public IP system.

    The company webpage was done with the help of a development suite called Flex2 and the result was an Adobe Flash application. To increase webpage dynamics a second page was developed for the company to have the ability to change and configure the main company webpage. An authentication service was deployed to configuration page to increase its security. As an engine and a substitute for lack of functionality and security in Adobe Flash simplePHP web service was used to connect Flash with a PHP script on its server.

    The payment system was developed with the help of PHP, MySQL and JavaScript. The system uses Paypal IPN service for money transaction and transaction validation

    A standalone web server with Apache2, PHP 5.0 and MySQL was deployed to the hotspot system to reduce the need of having an authentication system on a commercial Internet based web hotel.

  • 99.
    Bartsch, Steffen
    et al.
    Universität Kassel/provet.
    Boos, Carina
    Universität Kassel/provet.
    Canova, Gamze
    Universität Kassel/provet.
    Dyck, Dominic
    Universität Kassel/provet.
    Henhapl, Birgit
    Universität Kassel/provet.
    Schultheis, Michael
    Universität Kassel/provet.
    Volkamer, Melanie
    Universität Kassel/provet.
    Interdisziplinäres Bewertungskonzept für Risiken auf Webseiten2014In: Workshop RiskKom der GI-FGn SECMGT & ECOM auf der Informatik 2014, 2014, p. 2069-2078Conference paper (Refereed)
    Abstract [en]

    Dieser Beitrag beschreibt ein Konzept zur Verbesserung der Sicherheit von Nutzern im Internet: Angepasst auf die jeweilige IT-Sicherheitsexpertise sowie seiner Bereitschaft, Risiken einzugehen, werden dem Nutzer in risikoreichen Situationen unterschiedliche Interventionen geboten. Die Entscheidung, ob und welches Risiko existiert, wird auf rechtlicher und technischer Ebene getroffen: Indikatoren, ob Daten- und Verbraucherschutz eingehalten werden sowie ob grundlegende Maßnahmen der IT-Sicherheit umgesetzt sind, werden automatisiert erkannt und ausgewertet. Auf Grundlage der Risikoeinstufung des jeweiligen Szenarios sowie des antizipierten Risikoverhaltens und der IT-Sicherheitsexpertise des Nutzers wird über die Art der Intervention entschieden: Zusätzlich zu Warnmeldungen, die den Nutzer im Surfverhalten unterbrechen, existieren passive Interventionen, die den Nutzer nicht in seiner Handlung behindern, sowie eine permanente Anzeige über den Sicherheitsstatus einer Seite. 

  • 100.
    Bartsch, Steffen
    et al.
    Technische Universität Darmstadt.
    Volkamer, Melanie
    Technische Universität Darmstadt.
    Expert Knowledge for Contextualized Warnings2014Report (Other academic)
    Abstract [en]

    Users are bothered by too many security warnings in a vari- ety of applications. To reduce the number of unnecessary warnings, de- velopers cannot continue to report technical security problems. Instead, they need to consider the actual risks of the context for the decision of whether and how to warn – contextualized warnings. For this risk assess- ment, developers need to encode expert knowledge. Given the number and complexity of the risks – for example, in Web browsing –, eliciting and encoding the expert knowledge is challenging. In this paper, we pro- pose a holistic methodology for an abstract risk assessment that builds upon prior concepts from risk management, such as decision trees. The result of the methodology is an abstract risk model – a model to as- sess the risk for the concrete context. In a case study, we show how this methodology can be applied to warnings in Web browsers.

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