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  • 251.
    Bergdahl, Christopher
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Intergrated Computer systems. Linköping University, The Institute of Technology.
    Modeling Air Combat with Influence Diagrams2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Air combat is a complex situation, training for it and analysis of possible tactics are time consuming and expensive. In order to circumvent those problems, mathematical models of air combat can be used. This thesis presents air combat as a one-on-one influence diagram game where the influence diagram allows the dynamics of the aircraft, the preferences of the pilots and the uncertainty of decision making in a structural and transparent way to be taken into account. To obtain the players’ game optimal control sequence with respect to their preferences, the influence diagram has to be solved. This is done by truncating the diagram with a moving horizon technique and determining and implementing the optimal controls for a dynamic game which only lasts a few time steps.

    The result is a working air combat model, where a player estimates the probability that it resides in any of four possible states. The pilot’s preferences are modeled by utility functions, one for each possible state. In each time step, the players are maximizing the cumulative sum of the utilities for each state which each possible action gives. These are weighted with the corresponding probabilities. The model is demonstrated and evaluated in a few interesting aspects. The presented model offers a way of analyzing air combat tactics and maneuvering as well as a way of making autonomous decisions in for example air combat simulators. 

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  • 252.
    Berger, Lutz
    et al.
    Berger IT-COSMOS GmbH, Bavaria, Germany.
    Sjölund, Martin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Thiele, Bernhard
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Code Generation for STM32F4 Boards with Modelica Device Drivers: [Work in Progress]2017In: Proceedings of the 8th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, Association for Computing Machinery (ACM), 2017, p. 77-80Conference paper (Refereed)
  • 253.
    Bergfeldt, Nicklas
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Towards detached communication for robot cooperation2005Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This licentiate thesis deals with communication among cooperating mobile robots. Up until recently, most robotics research has focused on developing single robots that should accomplish a certain task. Now, it looks like we have come to a point where the need for multiple, cooperating robots is increasing since there are certain things that simply are not possible to do with a single robot. The major reasons, as described in this thesis, that make the use of multiple robots particularly interesting are distribution (it may be impossible to be in two places at the same time), parallelism (major speed improvements can be achieved by using many robots simultaneously), and simplicity (several, individually simpler, robots might be more feasible than a single, more complex robot). The field of cooperative robotics is multi-faceted, integrating a number of distinct fields such as social sciences, life sciences, and engineering. As a consequence of this, there are several sub-areas within cooperative robotics that can be identified and these are subsequently described here as well. To achieve coordinated behaviour within a multi-robot team communication can be used to ease the necessity of individual sensing (because of, for instance, calculation complexity), and with respect to this two different explicit approaches have been identified. As the survey presented here shows, the first of these approaches has already been extensively investigated, whereas the amount of research covering the second approach within the domain of adaptive multi-robot systems has been very limited. This second path is chosen and preliminary experiments are presented that indicate the usefulness of more complex representations to accomplish cooperation. More specifically, this licentiate thesis presents initial experiments that will serve as a starting point where the role and relevance of the ability to communicate using detached representations in planning and communication about future actions and events will be studied. Here, an unsupervised classifier is found to have the basic characteristics needed to initiate future investigations. Furthermore, two projects are presented that in particular serve to support future research; a robot simulator and an extension turret for remote control and monitoring of a physical, mobile robot. Detailed descriptions of planned future investigations are also discussed for the subsequent PhD work.

  • 254. Berggren, Martin
    et al.
    Ekström, Sven-Erik
    Uppsala universitet, Avdelningen för teknisk databehandling.
    Nordström, Jan
    Uppsala universitet, Avdelningen för teknisk databehandling.
    A discontinuous Galerkin extension of the vertex-centered edge-based finite volume method2009In: Communications in Computational Physics, ISSN 1815-2406, Vol. 5, p. 456-468Article in journal (Refereed)
    Download full text (pdf)
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  • 255. Order onlineBuy this publication >>
    Berglund, Aseel
    Linköping University, Department of Computer and Information Science, ASLAB - Application Systems Laboratory. Linköping University, The Institute of Technology.
    Augmenting the Remote Control: Studies in Complex Information Navigation for Digital TV2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The transition to digital TV is changing the television set into an entertainment as well as information supplier device that provides two-way communication with the viewer. However, the present remote control device is not appropriate for navigation through the huge amount of services and information provided by the future digital TV, presumably also a device for accessing the Internet. One possibility for coping with the complex information navigation required by TV viewers is an augmentation of the interaction tools currently available for TV. Two approaches to such an augmentation are investigated in this thesis: linking paper-based TV guides to the digital TV and enhancing the remote control unit with speech interaction.

    Augmentation of paper-based TV guides is a futuristic research approach based on the integration of paper-based TV guides into computation technology. This solution provides interactive paper-based TV guides that also function as a remote control for the TV. A prototype system is developed and explorative studies are conducted to investigate this approach. These studies indicate the benefits of integrating paper-based TV guides into the TV set. They also illuminate the potential to provide innovative solutions for home information systems. Integrating familiar physical artefacts, such as paper and pen into TV technology may provide easy access to information services usually provided by PCs and the Internet. Thus, the same augmentation needed for TV as an entertainment device also opens up new communication channels for providing society information to citizens who do not feel comfortable with conventional computers.

    The thesis also reports on studies of speech interfaces for TV information navigation. Traditional speech interfaces have several common problems, such as user acceptance and misinterpretation of user input. These problems are investigated in empirical and explorative studies with implementation of mockups and running research systems. We have found that the pragmatic solution of augmenting remote control devices by speech is a suitable solution that eases information navigation and search.

    List of papers
    1. Speech Enhanced Remote Control for Media Terminal
    Open this publication in new window or tab >>Speech Enhanced Remote Control for Media Terminal
    2001 (English)In: Proceedings of Eurospeech’01, Aalborg, Denmark, 2001, Vol. 4, p. 2685–2688-Conference paper, Published paper (Refereed)
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13519 (URN)
    Available from: 2004-06-20 Created: 2004-06-20 Last updated: 2013-09-13
    2. Multimodal Dialogue Systems for Interactive TV Applications
    Open this publication in new window or tab >>Multimodal Dialogue Systems for Interactive TV Applications
    2002 (English)In: Proceedings of the 4th IEEE International Conference on Multimodal Interfaces 2002 (ICMI’02), Pittsburgh, USA, 2002, p. 117-122Conference paper, Published paper (Refereed)
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13520 (URN)
    Available from: 2004-06-20 Created: 2004-06-20 Last updated: 2020-01-23
    3. Using speech and dialogue for interactive TV navigation
    Open this publication in new window or tab >>Using speech and dialogue for interactive TV navigation
    2004 (English)In: Interactive Access in the Information Society (UAIS), ISSN 1615-5289, Vol. 3, no 3-4, p. 224-238Article in journal (Refereed) Published
    Abstract [en]

    Interaction techniques for interactive television (iTV) are currently complex and difficult to use for a wide-range of viewers. Few previous studies have dealt with the potential benefits of multimodal dialogue interaction in the context of iTV for the purpose of flexibility, usability, efficiency, and accessibility. This paper investigates the benefits of introducing speech and connected dialogue for iTV interaction, and presents a case study in which a prototype system was built allowing users to navigate the information space and control the operation of the TV by a speech-based natural language interface. The system was evaluated by analysing the user experience in five categories capturing essential aspects of iTV interaction: interaction style, information load, data access, effectiveness and initiative. Design considerations relevant for speech and dialogue information systems for TV interfaces also emerged from the analysis.

    Place, publisher, year, edition, pages
    SpringerLink, 2004
    Keywords
    Electronic program guide, Universal access, Speech interaction, iTV
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13521 (URN)10.1007/s10209-004-0106-x (DOI)
    Available from: 2004-06-20 Created: 2004-06-20 Last updated: 2020-01-23Bibliographically approved
    4. Error Resolution Strategies for Interactive Television Speech Interfaces
    Open this publication in new window or tab >>Error Resolution Strategies for Interactive Television Speech Interfaces
    2003 (English)In: Proceedings of the Ninth IFIP TC13 International Conference on Human-Computer Interaction, INTERACT, Zürich, Switzerland, 2003, p. 105–112-Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-13522 (URN)
    Available from: 2004-06-20 Created: 2004-06-20 Last updated: 2018-01-13
    5. The Paper Remote: An Augmented TV Guide and Remote Control
    Open this publication in new window or tab >>The Paper Remote: An Augmented TV Guide and Remote Control
    2005 (English)In: Universal Access in the Information Society (UAIS), ISSN 1615-5289, Vol. 4, no 4, p. 300-327Article in journal (Refereed) Published
    Abstract [en]

    The television (TV) is one of the most common entertainment devices in homes. Searching and finding TV programs is a common task and using TV guides is one way of performing this. This paper presents three studies that are focused on examining audiences’ TV habits and TV guide usage, evaluating a new concept based on linking paper and pen with TV technology, and studying the audiences’ attitudes toward and anticipated interest in the future guide. The results of our first study emphasize the value of using paper based TV guides and also identify the deficiencies. We also found indications that the advantages and disadvantages of paper-based TV guides are related to the physical properties of paper. Thus, we suggest a solution that uses digital pen and paper technology to offer a new interaction method for TV. A research system “Paper Remote”, is developed and used in the two subsequent studies. Viewers tick designated areas on the paper-based guide to perform actions such as channel switching. However, this solution is not a substitute for the remote control device. We argue that these user studies on linking digital paper to the TV for everyday information navigation illuminate the possibilities of providing innovative solutions also for home information systems also.

    Keywords
    Interactive TV, Paper interfaces, Home information system, Electronic program guides
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13523 (URN)10.1007/s10209-004-0108-8 (DOI)
    Available from: 2004-06-20 Created: 2004-06-20 Last updated: 2011-01-11
    Download full text (pdf)
    FULLTEXT01
  • 256.
    Berglund, Aseel
    et al.
    Linköping University, Department of Computer and Information Science, ASLAB - Application Systems Laboratory. Linköping University, The Institute of Technology.
    Qvardfordt, P.
    Error Resolution Strategies for Interactive Television Speech Interfaces2003In: Proceedings of the Ninth IFIP TC13 International Conference on Human-Computer Interaction, INTERACT, Zürich, Switzerland, 2003, p. 105–112-Conference paper (Refereed)
  • 257.
    Berglund, Erik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Designing electronic reference documentation for software component libraries2003In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 68, no 1, p. 65-75Article in journal (Refereed)
    Abstract [en]

    Contemporary software development is based on global sharing of software component libraries. As a result, programmers spend much time reading reference documentation rather than writing code, making library reference documentation a central programming tool. Traditionally, reference documentation is designed for textbooks even though it may be distributed online. However, the computer provides new dimensions of change, evolution, and adaptation that can be utilized to support efficiency and quality in software development. What is difficult to determine is how the electronic text dimensions best can be utilized in library reference documentation.

    This article presents a study of the design of electronic reference documentation for software component libraries. Results are drawn from a study in an industrial environment based on the use of an experimental electronic reference documentation (called Dynamic Javadoc or DJavadoc) used in a real-work situation for 4 months. The results from interviews with programmers indicate that the electronic library reference documentation does not require adaptation or evolution on an individual level. More importantly, reference documentation should facilitate the transfer of code from documentation to source files and also support the integration of multiple documentation sources.

  • 258. Order onlineBuy this publication >>
    Berglund, Erik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Library Communication Among Programmers Worldwide2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Programmers worldwide share components and jointly develop components on a global scale in contemporary software development. An important aspect of such library-based programming is the need for technical communication with regard to libraries – library communication. As part of their work, programmers must discover, study, and learn as well as debate problems and future development. In this sense, the electronic, networked media has fundamentally changed programming by providing new mechanisms for communication and global interaction through global networks such as the Internet. Today, the baseline for library communication is hypertext documentation. Improvements in quality, efficiency, cost and frustration of the programming activity can be expected by further developments in the electronic aspects of library communication.

    This thesis addresses the use of the electronic networked medium in the activity of library communication and aims to discover design knowledge for communication tools and processes directed towards this particular area. A model of library communication is provided that describes interaction among programmer as webs of interrelated library communities. A discussion of electronic, networked tools and processes that match such a model is also provided. Furthermore, research results are provided from the design and industrial valuation

    of electronic reference documentation for the Java domain. Surprisingly, the evaluation did not support individual adaptation (personalization). Furthermore, global library communication processes have been studied in relation to open-source documentation and user-related bug handling. Open-source documentation projects are still relatively uncommon even in open-source software projects. User-related Open-source does not address the passive behavior users have towards bugs. Finally, the adaptive authoring process in electronic reference documentation is addressed and found to provide limited support for expressing the electronic, networked dimensions of authoring requiring programming skill by technical writers.

    Library communication is addressed here by providing engineering knowledge with regards to the construction of practical electronic, networked tools and processes in the area. Much of the work has been performed in relation to Java library communication and therefore the thesis has particular relevancefor the object-oriented programming domain. A practical contribution of the work is the DJavadoc tool that contributes to the development of reference documentation by providing adaptive Java reference documentation.

    List of papers
    1. Designing electronic reference documentation for software component libraries
    Open this publication in new window or tab >>Designing electronic reference documentation for software component libraries
    2003 (English)In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 68, no 1, p. 65-75Article in journal (Refereed) Published
    Abstract [en]

    Contemporary software development is based on global sharing of software component libraries. As a result, programmers spend much time reading reference documentation rather than writing code, making library reference documentation a central programming tool. Traditionally, reference documentation is designed for textbooks even though it may be distributed online. However, the computer provides new dimensions of change, evolution, and adaptation that can be utilized to support efficiency and quality in software development. What is difficult to determine is how the electronic text dimensions best can be utilized in library reference documentation.

    This article presents a study of the design of electronic reference documentation for software component libraries. Results are drawn from a study in an industrial environment based on the use of an experimental electronic reference documentation (called Dynamic Javadoc or DJavadoc) used in a real-work situation for 4 months. The results from interviews with programmers indicate that the electronic library reference documentation does not require adaptation or evolution on an individual level. More importantly, reference documentation should facilitate the transfer of code from documentation to source files and also support the integration of multiple documentation sources.

    Keywords
    Electronic documentation, Programming, Reference documentation
    National Category
    Engineering and Technology Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-13490 (URN)10.1016/S0164-1212(02)00136-X (DOI)
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2018-01-13
    2. Helping Users Live With Bugs
    Open this publication in new window or tab >>Helping Users Live With Bugs
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:liu:diva-13491 (URN)
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2010-01-13
    3. Open-Source Documentation: in search of user-driven, just-in-time writing
    Open this publication in new window or tab >>Open-Source Documentation: in search of user-driven, just-in-time writing
    2001 (English)In: Proceedings of SIGDOC 2001, October 21– 24, 2001 in Santa Fe, NM, Santa Fee, NM: ACM , 2001, p. 132-141Conference paper, Published paper (Refereed)
    Abstract [en]

    Iterative development models allow developers to respond quickly to changing user requirements, but place increasing demands on writers who must handle increasing amounts of change with ever-decreasing resources. In the software development world, one solution to this problem is open-source development: allowing the users to set requirements and priorities by actually contributing to the development of the software. This results in just-in-time software improvements that are explicitly user-driven, since they are actually developed by users.In this article we will discuss how the open source model can be extended to the development of documentation. In many open-source projects, the role of writer has remained unchanged: documentation development remains a specialized activity, owned by a single writer or group of writers, who work as best they can with key developers and frequently out-of-date specification documents. However, a potentially more rewarding approach is to open the development of the documentation to the same sort of community involvement that gives rise to the software: using forums and mailing lists as the tools for developing documentation, driven by debate and dialogue among the actual users and developers.Just as open-source development blurs the line between user and developer, open-source documentation will blur the line between reader and writer. Someone who is a novice reader in one area may be an expert author in another. Two key activities emerge for the technical writer in such a model: as gatekeeper and moderator for FAQs and formal documentation, and as literate expert user of the system they are documenting.

    Place, publisher, year, edition, pages
    Santa Fee, NM: ACM, 2001
    National Category
    Engineering and Technology Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-13492 (URN)10.1145/501516.501543 (DOI)
    Conference
    SIGDOC 2001
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2018-01-13
    4. Writing for Adaptable Documentation
    Open this publication in new window or tab >>Writing for Adaptable Documentation
    2000 (English)In: Proceedings of IPCC/SIGDOC 2000, September 24 – 27, Cambridge, Massachusetts, IEEE , 2000, p. 497-508Conference paper, Published paper (Refereed)
    Abstract [en]

    The rapid development of reusable software components results in an information overload problem in the development process. Software developers must read large amounts of documentation. Adaptive documentation is one way to address this problem and support efficient reading. However, in our view, adaptive documentation requires a writing process that delivers the pedagogical strategies for adaptivity. The article takes a stance in a project on adaptive software reference documentation and discusses the requirements on writing. It also discusses writing trends and Web languages in relation to adaptivity. It is concluded that describing change in documentation is not supported on an authoring level but rather on a programming level

    Place, publisher, year, edition, pages
    IEEE, 2000
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13493 (URN)10.1109/IPCC.2000.887306 (DOI)0-7803-6431-7 (ISBN)
    Conference
    2000 Joint IEEE International and 18th Annual Conference on Computer Documentation (IPCC/SIGDOC 2000) Professional Communication Conference, 24-27 September 2000, Cambridge, MA, UK
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2015-04-09
    5. Dynamic Software Component Documentation
    Open this publication in new window or tab >>Dynamic Software Component Documentation
    2000 (English)In: Proceedings of the Second Workshop on Learning Software Organizations, in conjunction with the Second International Conference on Product Focused software Process Improvement June 20 2000, Oulu, Finland, 2000Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-13494 (URN)
    Conference
    The Second International Conference on Product Focused software Process Improvement, June 20 2000, Oulu, Finland
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2018-01-13
    6. Intermediate Knowledge trough Conceptual Source-Code Organization
    Open this publication in new window or tab >>Intermediate Knowledge trough Conceptual Source-Code Organization
    1998 (English)In: Proceedings of the 10:th International Conference on Software Engineering and Knowledge Engineering, June 18-20 San Francisco Bay CA USA, San Diego: Knowledge Systems Institute , 1998, p. 112-115Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    San Diego: Knowledge Systems Institute, 1998
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-13495 (URN)0-9641699-9-1 (ISBN)
    Conference
    10:th International Conference on Software Engineering and Knowledge Engineering
    Available from: 2002-10-20 Created: 2002-10-20 Last updated: 2018-01-13
    Download full text (pdf)
    FULLTEXT01
  • 259.
    Berglund, Erik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Use-Oriented Documentation in Software Development1999Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Software documentation is an important tool in modem component-based programming. Building software applications requires detailed knowledge about a vast number of components and the structures they form. This knowledge is often acquired by reading reference documentation of application-programming interfaces (APIs). Thus, the design of the API reference documentation and its reading support affect the cost and quality of software development.

    We examine how efficiency and quality in software development can be increased through the design of software documentation and reading support for software documentation. The thesis reports on the DJavadoc project and the reading support for online Java API reference documentation that it provides. The Java API reference documentation can be viewed as a collection of documentation designed for multiple needs. As a consequence, ex:cessive information is present in most situations. In DJavadoc we have extended the official Java API reference documentation to achieve control over the visibility of information types. DJavadoc adds client-side, real-time redesign to the documentation to support the design of multiple views. As a result, the reader may further design views of the information that are more in line with the reader's personal and changing needs. In the thesis we also discuss online API reference documentation and its role in programming.

    Our preliminary studies support the design strategy taken in DJavadoc. The DJavadoc architecture has also proven suitable for continuos redesign of online documentation. Furthermore, our work provides several future research directions for software documentation and communication of functionality. The Javadoc approach can be developed to achieve more use-oriented documentation. However, the need of use-oriented documentation may also have impact on the Java programming language and ultimately object orientation.

  • 260.
    Berglund, Erik
    et al.
    Linköping University, Department of Computer and Information Science, ASLAB - Application Systems Laboratory. Linköping University, The Institute of Technology.
    Bång, Magnus
    Linköping University, Department of Computer and Information Science, ASLAB - Application Systems Laboratory. Linköping University, The Institute of Technology.
    Requirements for Distributed User-Interfaces in Ubiquitous Computing Networks2002In: Proceedings of First International Conference on Mobile and Ubiquitous Multimedia (MUM2002), Oulu: Oulu , 2002, p. 99-Conference paper (Refereed)
  • 261.
    Berglund, Erik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces.
    Distributed Interactive Simulation for Group-Distance Exercises on the Web1998In: 1998 International Conference on Web-based Modelling Simulation,1998, San Diego, CA: Society for Computer Simulation International , 1998, p. 91-95Conference paper (Refereed)
  • 262.
    Berglund, Erik
    et al.
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Dynamic Software Component Documentation2000In: Proceedings of the Second Workshop on Learning Software Organizations, in conjunction with the Second International Conference on Product Focused software Process Improvement June 20 2000, Oulu, Finland, 2000Conference paper (Refereed)
  • 263.
    Berglund, Erik
    et al.
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Intermediate Knowledge trough Conceptual Source-Code Organization1998In: Proceedings of the 10:th International Conference on Software Engineering and Knowledge Engineering, June 18-20 San Francisco Bay CA USA, San Diego: Knowledge Systems Institute , 1998, p. 112-115Conference paper (Refereed)
  • 264.
    Berglund, Erik
    et al.
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Priestley, Michael
    IBM Toronto Lab, Canada.
    Open-Source Documentation: in search of user-driven, just-in-time writing2001In: Proceedings of SIGDOC 2001, October 21– 24, 2001 in Santa Fe, NM, Santa Fee, NM: ACM , 2001, p. 132-141Conference paper (Refereed)
    Abstract [en]

    Iterative development models allow developers to respond quickly to changing user requirements, but place increasing demands on writers who must handle increasing amounts of change with ever-decreasing resources. In the software development world, one solution to this problem is open-source development: allowing the users to set requirements and priorities by actually contributing to the development of the software. This results in just-in-time software improvements that are explicitly user-driven, since they are actually developed by users.In this article we will discuss how the open source model can be extended to the development of documentation. In many open-source projects, the role of writer has remained unchanged: documentation development remains a specialized activity, owned by a single writer or group of writers, who work as best they can with key developers and frequently out-of-date specification documents. However, a potentially more rewarding approach is to open the development of the documentation to the same sort of community involvement that gives rise to the software: using forums and mailing lists as the tools for developing documentation, driven by debate and dialogue among the actual users and developers.Just as open-source development blurs the line between user and developer, open-source documentation will blur the line between reader and writer. Someone who is a novice reader in one area may be an expert author in another. Two key activities emerge for the technical writer in such a model: as gatekeeper and moderator for FAQs and formal documentation, and as literate expert user of the system they are documenting.

  • 265.
    Berglund, Fredrika
    Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems. Linköping University, The Institute of Technology.
    Management control and strategy: a case study of pharmaceutical drug development2002Licentiate thesis, monograph (Other academic)
    Abstract [en]

    How are formal management controls designed and used in research & development (R&D)? The purpose of this study is to explain how such systems are designed and used in formulating and implementing strategies in a pharmaceutical product development organisation. The study uses a contingency approach to investigate how the control system is adjusted to the business strategy of the firm. A case study was conducted in AstraZeneca R&D where strategic planning, budgeting, project management, goals and objective systems and the reward systems were studied.

    Managers, external investors and researchers increasingly recognize the strategic importance of R&D activities. This has inspired researchers and practitioners to develop formal systems and methods for controlling R&D activities. There is, however, previous research in which a resistance towards using formal control systems to manage R&D was observed. This contrasts the general perception of management control systems as important in implementing and formulating strategies.

    The results of this study show that formal management control have an important role in managing R&D. It also explains how the system is adjusted to the business strategy of the studied firm. Different control systems (e.g. budget, project management) were found to be designed and used in different ways. This implies that it is not meaningful to discuss whether the entire control system of a firm is tight or loose and/or used interactively or diagnostically. Rather, the systems may demonstrate combinations of these characteristics. The control systems of the studied firm were found to be used differently in the project and the functional dimensions. The control systems were also designed and used in different ways at different organisational levels. Comprehensive and rather detailed studies of control systems are called for in order to understand how they are designed and used in organisations. Such studies may explain some contradictory results in previous studies on how control systems are adjusted to business strategy. 

  • 266.
    Bergman, Bengt
    Linköping University, Department of Computer and Information Science.
    E-fraud E-fraud, state of the art and counter measures2005Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    This thesis investigates fraud and the situation on Internet with e-commerce today, to point on some potential threats and needed countermeasures. The work reviews several state of the art e-fraud schemes, techniques used in the schemes and statistics on the extent of e-fraud. This part shows that e-frauds are today both sophisticated and widespread.

    Since real world frauds are deemed impossible to fully cover in order to predict potential new e-frauds, the thesis adopts a different approach. It suggests two abstraction models for fraud cases, a protocol model and a functional model. These are used to perform analysis on case studies on both telecom frauds and e-frauds. The analysis presents characteristics for both types of frauds. Using one of the abstraction models, the functional model, conceptually similar cases among telecom frauds as well as e-fraud cases are identified. The similar cases in each category are then compared, using the other abstraction model, the protocol model. The study shows that concepts from telecom frauds already exist in e-frauds.

    Several challenges and some possibilities in e-fraud prevention and detection are also extracted in the comparative study of the different categories. The major consequence of the challenges is e-frauds’ higher scalability compared to telecom frauds.

    Finally, this thesis covers several existing countermeasures in e-commerce along with specific countermeasures against auction fraud, phishing and spam. However, it is shown that these countermeasures do not address the challenges in e-fraud prevention and detection to a satisfactory extent. Therefore, this thesis proposes several high-level countermeasures in order to address the challenges.

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  • 267.
    Bergström, David
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Bayesian optimization for selecting training and validation data for supervised machine learning: using Gaussian processes both to learn the relationship between sets of training data and model performance, and to estimate model performance over the entire problem domain2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Validation and verification in machine learning is an open problem which becomes increasingly important as its applications becomes more critical. Amongst the applications are autonomous vehicles and medical diagnostics. These systems all needs to be validated before being put into use or else the consequences might be fatal.

    This master’s thesis focuses on improving both learning and validating machine learning models in cases where data can either be generated or collected based on a chosen position. This can for example be taking and labeling photos at the position or running some simulation which generates data from the chosen positions.

    The approach is twofold. The first part concerns modeling the relationship between any fixed-size set of positions and some real valued performance measure. The second part involves calculating such a performance measure by estimating the performance over a region of positions.

    The result is two different algorithms, both variations of Bayesian optimization. The first algorithm models the relationship between a set of points and some performance measure while also optimizing the function and thus finding the set of points which yields the highest performance. The second algorithm uses Bayesian optimization to approximate the integral of performance over the region of interest. The resulting algorithms are validated in two different simulated environments.

    The resulting algorithms are applicable not only to machine learning but can also be used to optimize any function which takes a set of positions and returns a value, but are more suitable when the function is expensive to evaluate.

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  • 268. Bergström, E.
    et al.
    Vimarlund, Vivian
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Arbetet med att motverka brott inom socialförsäkringsförmånerna, förstudie, 20062006Report (Other academic)
    Abstract [sv]

       

  • 269.
    Bergström, Gustav
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Duberg, Elsa
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Holmén, Karin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Lundell, Tobias
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Lönnberg, Robert
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Mandelius, Marcus
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Olsson, Christian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Ström, Björn
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Äng, Oscar
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    A study in web development: An onlinewatch store as a web application2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report on the development and implementation of the web shop “Urballa Ur”, a web application developed by nine students at Linköping university. The report illustrates the methodology and process with intention to answer the question “How can an online watch store be implemented to increase sales?”. During the process the agile method scrum has been used as a working method. A survey and a market plan was created and the results were used as a foundation for the backlog and implementation process. Additionally, a thorough theoretical study was conducted to found the report in academic research. The results of the study is discussed and the conclusion shows that, by creating a thorough backlog and a solid theoretical background, it is possible to develop a web shop with the requirements to answer the question.

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    fulltext
  • 270.
    Bergström, Patrik
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Department of Computer and Information Science, Artificial Intelligence and Intergrated Computer systems. Linköping University, The Institute of Technology.
    Automated Setup of Display Protocols2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Radiologists' workload has been steadily increasing for decades. As digital technology matures it improves the workflow for radiology departments and decreases the time necessary to examine patients. Computer systems are widely used in health care and are for example used to view radiology images. To simplify this, display protocols based on examination data are used to automatically create a layout and hang images for the user. To cover a wide variety of examinations hundreds of protocols must be created, which is a time-consuming task and the system can still fail to hang series if strict requirements on the protocols are not met. To remove the need for this manual step we propose to use machine learning based on past manually corrected presentations. The classifiers are trained on the metadata in the examination and how the radiologist preferred to hang the series. The chosen approach was to create classifiers for different layout rules and then use these predictions in an algorithm for assigning series types to individual image slots according to categories based on metadata, similar to how display protocol works. The resulting presentations shows that the system is able to learn, but must increase its prediction accuracy if it is to be used commercially. Analyses of the different parts show that increased accuracy in early steps should improve overall success.

    Download full text (pdf)
    AutomatedSetupOfDisplayProtocols
  • 271. Bergum, S.
    et al.
    Rapp, Birger
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, EISLAB - Economic Information Systems.
    Challenges of managing remote workers Some empirical results from interviews in Sweden and Norway1998In: ITS-98 Conference,1998, 1998Conference paper (Refereed)
  • 272.
    Bergvall, Jacob
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Svensson, Louise
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Risk analysis review2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The risk analysis process is the foundation of creating secure systems. An accurate and well defined risk analysis will therefore be a big help for any company, indicating what resources are needed and where they should be put to use. It can be difficult to know which risk analysis methodology to use given a set of parameters such as available resources, time, money etc. In this review we will introduce several different risk analysis methodologies and classify them using our risk analysis classification system. Our classification points out some of the pros and cons for each method, making it easier to choose the one best suited for a specific scenario. We will also connect the presented methods with real-world usage of said methods. To do this we have conducted interviews with IT-security experts at several major companies and we will present previous documented usage of risk analysis methods. Larger companies tend to develop their own methods for risk analysis, and smaller companies that do not have enough time or resources to develop their own methods are more likely to use already existing methods. With that said we believe that anyone that works with risk analysis could have use of our review.

    Download full text (pdf)
    Risk analysis review
  • 273.
    Besancon, Lonni
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Univ Paris Saclay, France.
    Sereno, Mickael
    Inria, France; Univ Paris Saclay, France.
    Yu, Lingyun
    Univ Groningen, Netherlands.
    Ammi, Mehdi
    Univ Paris 08, France.
    Isenberg, Tobias
    Inria, France.
    Hybrid Touch/Tangible Spatial 3D Data Selection2019In: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 38, no 3, p. 553-567Article in journal (Refereed)
    Abstract [en]

    We discuss spatial selection techniques for three-dimensional datasets. Such 3D spatial selection is fundamental to exploratory data analysis. While 2D selection is efficient for datasets with explicit shapes and structures, it is less efficient for data without such properties. We first propose a new taxonomy of 3D selection techniques, focusing on the amount of control the user has to define the selection volume. We then describe the 3D spatial selection technique Tangible Brush, which gives manual control over the final selection volume. It combines 2D touch with 6-DOF 3D tangible input to allow users to perform 3D selections in volumetric data. We use touch input to draw a 2D lasso, extruding it to a 3D selection volume based on the motion of a tangible, spatially-aware tablet. We describe our approach and present its quantitative and qualitative comparison to state-of-the-art structure-dependent selection. Our results show that, in addition to being dataset-independent, Tangible Brush is more accurate than existing dataset-dependent techniques, thus providing a trade-off between precision and effort.

  • 274.
    Bhat, Anand
    et al.
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Samii, Soheil
    General Motors, USA.
    Rajkumar, Ragunathan
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Practical Task Allocation for Software Fault-Tolerance and Its Implementation in Embedded Automotive Systems2017Conference paper (Refereed)
    Abstract [en]

    Due to the advent of active safety features and automated driving capabilities, the complexity of embedded computing systems within automobiles continues to increase. Such advanced driver assistance systems (ADAS) are inherently safety-critical and must tolerate failures in any subsystem. However, fault-tolerance in safety-critical systems has been traditionally supported by hardware replication, which is prohibitively expensive in terms of cost, weight, and size for the automotive market. Recent work has studied the use of software-based fault-tolerance techniques that utilize task-level hot and cold standbys to tolerate fail-stop processor and task failures. The benefit of using standbys is maximal when a task and any of its standbys obey the placement constraint of not being co-located on the same processor. We propose a new heuristic based on a "tiered" placement constraint, and show that our heuristic produces a better task assignment that saves at least one processor up to 40% of the time relative to the best known heuristic to date. We then introduce a task allocation algorithm that, for the first time to our knowledge, leverages the run-time attributes of cold standbys. Our empirical study finds that our heuristic uses no more than one additional processor in most cases relative to an optimal allocation that we construct for evaluation purposes using a creative technique. We have designed and implemented our software fault-tolerance framework in AUTOSAR, an automotive industry standard. We use this implementation to provide an experimental evaluation of our task-level fault-tolerance features. Finally, we present an analysis of the worst-case behavior of our task recovery features.

  • 275.
    Bhat, Anand
    et al.
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Samii, Soheil
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering. General Motors, USA.
    Rajkumar, Ragunathan
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Recovery Time Considerations in Real-Time Systems Employing Software Fault Tolerance2018In: 30th Euromicro Conference on Real-Time Systems (ECRTS 2018)}, 2018Conference paper (Refereed)
    Abstract [en]

    Safety-critical real-time systems like modern automobiles with advanced driving-assist features must employ redundancy for crucial software tasks to tolerate permanent crash faults. This redundancy can be achieved by using techniques like active replication or the primary-backup approach. In such systems, the recovery time which is the amount of time it takes for a redundant task to take over execution on the failure of a primary task becomes a very important design parameter. The recovery time for a given task depends on various factors like task allocation, primary and redundant task priorities, system load and the scheduling policy. Each task can also have a different recovery time requirement (RTR). For example, in automobiles with automated driving features, safety-critical tasks like perception and steering control have strict RTRs, whereas such requirements are more relaxed in the case of tasks like heating control and mission planning. In this paper, we analyze the recovery time for software tasks in a real-time system employing Rate-Monotonic Scheduling (RMS). We derive bounds on the recovery times for different redundant task options and propose techniques to determine the redundant-task type for a task to satisfy its RTR. We also address the fault-tolerant task allocation problem, with the additional constraint of satisfying the RTR of each task in the system. Given that the problem of assigning tasks to processors is a well-known NP-hard bin-packing problem we propose computationally-efficient heuristics to find a feasible allocation of tasks and their redundant copies. We also apply the simulated annealing method to the fault-tolerant task allocation problem with RTR constraints and compare against our heuristics.

  • 276. Order onlineBuy this publication >>
    Bhide, Ameya
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Design of High-Speed Time-Interleaved Delta-Sigma D/A Converters2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Digital-to-analog (D/A) converters (or DACs) are one the fundamental building blocks of wireless transmitters. In order to support the increasing demand for highdata-ate communication, a large bandwidth is required from the DAC. With the advances in CMOS scaling, there is an increasing trend of moving a large part of the transceiver functionality to the digital domain in order to reduce the analog complexity and allow easy reconguration for multiple radio standards. ΔΣ DACs can t very well into this trend of digital architectures as they contain a large digital signal processing component and oer two advantages over the traditionally used Nyquist DACs. Firstly, the number of DAC unit current cells is reduced which relaxes their matching and output impedance requirements and secondly, the reconstruction lter order is reduced.

    Achieving a large bandwidth from ΔΣ DACs requires a very high operating frequency of many-GHz from the digital blocks due to the oversampling involved. This can be very challenging to achieve using conventional ΔΣ DAC architectures, even in nanometer CMOS processes. Time-interleaved ΔΣ (TIDSM) DACs have the potential of improving the bandwidth and sampling rate by relaxing the speed of the individual channels. However, they have received only some attention over the past decade and very few previous works been reported on this topic. Hence, the aim of this dissertation is to investigate architectural and circuit techniques that can further enhance the bandwidth and sampling rate of TIDSM DACs.

    The rst work is an 8-GS/s interleaved ΔΣ DAC prototype IC with 200-MHz bandwidth implemented in 65-nm CMOS. The high sampling rate is achieved by a two-channel interleaved MASH 1-1 digital ΔΣ modulator with 3-bit output, resulting in a highly digital DAC with only seven current cells. Two-channel interleaving allows the use of a single clock for both the logic and the nal multiplexing. This requires each channel to operate at half the sampling rate i.e. 4 GHz. This is enabled by a high-speed pipelined MASH structure with robust static logic. Measurement results from the prototype show that the DAC achieves 200-MHz bandwidth, –57-dBc IM3 and 26-dB SNDR, with a power consumption of 68-mW at 1-V digital and 1.2-V analog supplies. This architecture shows good potential for use in the transmitter baseband. While a good linearity is obtained from this DAC, the SNDR is found to be limited by the testing setup for sending high-speed digital data into the prototype.

    The performance of a two-channel interleaved ΔΣ DAC is found to be very sensitive to the duty-cycle of the half-rate clock. The second work analyzes this eect mathematically and presents a new closed-form expression for the SNDR loss of two-channel DACs due to the duty cycle error (DCE) for a noise transfer function (NTF) of (1 — z—1)n. It is shown that a low-order FIR lter after the modulator helps to mitigate this problem. A closed-form expression for the SNDR loss in the presence of this lter is also developed. These expressions are useful for choosing a suitable modulator and lter order for an interleaved ΔΣ DAC in the early stage of the design process. A comparison between the FIR lter and compensation techniques for DCE mitigation is also presented.

    The nal work is a 11 GS/s 1.1 GHz bandwidth time-interleaved DAC prototype IC in 65-nm CMOS for the 60-GHz radio baseband. The high sampling rate is again achieved by using a two-channel interleaved MASH 1-1 architecture with a 4-bit output i.e only fteen analog current cells. The single clock architecture for the logic and the multiplexing requires each channel to operate at 5.5 GHz. To enable this, a new look-ahead technique is proposed that decouples the two channels within the modulator feedback path thereby improving the speed as compared to conventional loop-unrolling. Full speed DAC testing is enabled by an on-chip 1 Kb memory whose read path also operates at 5.5 GHz. Measurement results from the prototype show that the ΔΣ DAC achieves >53 dB SFDR, < —49 dBc IM3 and 39 dB SNDR within a 1.1 GHz bandwidth while consuming 117 mW from 1 V digital/1.2 V analog supplies. The proposed ΔΣ DAC can satisfy the spectral mask of the 60-GHz radio IEEE 802.11ad WiGig standard with a second order reconstruction lter.

    List of papers
    1. An 8-GS/s 200-MHz Bandwidth 68-mW ΔΣ DAC in 65-nm CMOS
    Open this publication in new window or tab >>An 8-GS/s 200-MHz Bandwidth 68-mW ΔΣ DAC in 65-nm CMOS
    2013 (English)In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 60, no 7, p. 387-391Article in journal (Refereed) Published
    Abstract [en]

    This brief presents an 8-GS/s 12-bit input ΔΣ digital-to-analog converter (DAC) with 200-MHz bandwidth in 65-nm CMOS. The high sampling rate is achieved by a two-channel interleaved MASH 1–1 digital ΔΣ modulator with 3-bit output, resulting in a highly digital DAC with only seven current cells. The two-channel interleaving allows the use of a single clock for both the logic and the final multiplexing. This requires each channel to operate at half the sampling rate, which is enabled by a high-speed pipelined MASH structure with robust static logic. Measurement results show that the DAC achieves 200-MHz bandwidth, 26-dB SNDR, and $-$57-dBc IMD3, with a power consumption of 68 mW at 1-V digital and 1.2-V analog supplies. This architecture shows potential for use in transmitter baseband for wideband wireless communication.

    Place, publisher, year, edition, pages
    Institute of Electrical and Electronics Engineers (IEEE), 2013
    Keywords
    Digital Delta Sigma modulator (DDSM), digital-to-analog converter (DAC), MASH, oversampling, time interleaving
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-96713 (URN)10.1109/TCSII.2013.2258272 (DOI)000322030600004 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research (SSF)||

    Available from: 2013-08-23 Created: 2013-08-23 Last updated: 2019-09-05
    2. Effect of Clock Duty-Cycle Error on Two-Channel Interleaved Delta Sigma DACs
    Open this publication in new window or tab >>Effect of Clock Duty-Cycle Error on Two-Channel Interleaved Delta Sigma DACs
    2015 (English)In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 62, no 7, p. 646-650Article in journal (Refereed) Published
    Abstract [en]

    Time-interleaved delta-sigma (Delta Sigma) modulation digital-to-analog converters (TIDSM DACs) have the potential for a wideband operation. The performance of a two-channel interleaved Delta Sigma DAC is very sensitive to the duty cycle of the half-rate clock. This brief presents a closed-form expression for the signal-to-noise-plus-distortion ratio (SNDR) loss of such DACs due to a duty-cycle error for modulators with a noise transfer function of (1 - z(-1))(n). Adding a low-order finite-impulse-response filter after the modulator helps to mitigate this problem. A closed-form expression for the SNDR loss in the presence of this filter is also developed. These expressions are useful for choosing a suitable modulator and filter order for an interleaved Delta Sigma DAC in the early stage of the design process.

    Place, publisher, year, edition, pages
    Institute of Electrical and Electronics Engineers (IEEE), 2015
    Keywords
    Delta-sigma (Delta Sigma) modulator; digital Delta Sigma modulator; digital-to-analog converter (DAC); duty cycle; finite-impulse-response (FIR) filter; time interleaving
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-120215 (URN)10.1109/TCSII.2015.2415691 (DOI)000357126000006 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research

    Available from: 2015-07-21 Created: 2015-07-20 Last updated: 2019-09-05
    3. A 11-GS/s 1.1-GHz Bandwidth Interleaved ΔΣ DAC for 60-GHz Radio in 65-nm CMOS
    Open this publication in new window or tab >>A 11-GS/s 1.1-GHz Bandwidth Interleaved ΔΣ DAC for 60-GHz Radio in 65-nm CMOS
    2015 (English)In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, E-ISSN 1558-173X, Vol. 50, no 10, p. 2306-2310Article in journal (Refereed) Published
    Abstract [en]

    This work presents an 11 GS/s 1.1 GHz bandwidth interleaved ΔΣ DAC in 65 nm CMOS for the 60 GHz radio baseband. The high sample rate is achieved by using a two-channel interleaved MASH 1–1 architecture with a 4 bit output resulting in a predominantly digital DAC with only 15 analog current cells. Two-channel interleaving allows the use of a single clock for the logic and the multiplexing which requires each channel to operate at half sampling rate of 5.5 GHz. To enable this, a look-ahead technique is proposed that decouples the two channels within the integrator feedback path thereby improving the speed as compared to conventional loop-unrolling. Measurement results show that the ΔΣ DAC achieves a 53 dB SFDR, -49 dBc IM3 and 39 dB SNDR within a 1.1 GHz bandwidth while consuming 117 mW from 1 V digital/1.2 V analog supplies. Furthermore, the proposed ΔΣ DAC can satisfy the spectral mask of the IEEE 802.11ad WiGig standard with a second order reconstruction filter.

    Place, publisher, year, edition, pages
    IEEE, 2015
    Keywords
    ΔΣ DAC; 60 GHz radio; High speed; IEEE 80211ad; MASH; WiGig; time-interleaving
    National Category
    Signal Processing Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-120624 (URN)10.1109/JSSC.2015.2460375 (DOI)000362359700008 ()
    Note

    Funding text: Swedish Foundation for Strategic Research (SSF); Swedish Research Council (VR); Swedish Innovation Agency (VINNOVA)

    Available from: 2015-08-19 Created: 2015-08-19 Last updated: 2019-09-05Bibliographically approved
    4. Critical Path Analysis of Two-channel Interleaved Digital MASH ΔΣ Modulators
    Open this publication in new window or tab >>Critical Path Analysis of Two-channel Interleaved Digital MASH ΔΣ Modulators
    2013 (English)In: 2013 NORCHI, 11–12 November, 2013, Vilnius, Lithuania, IEEE , 2013, p. 1-4Conference paper, Published paper (Refereed)
    Abstract [en]

    Implementation of wireless wideband transmitters using ΔΣ DACs requires very high speed modulators. Digital MASH ΔΣ modulators are good candidates for speed enhancement using interleaving because they require only adders and can be cascaded. This paper presents an analysis of the integrator critical path of two-channel interleaved ΔΣ modulators. The bottlenecks for a high-speed operation are identified and the performance of different logic styles is compared. Static combinational logic shows the best trade-off and potential for use in such high speed modulators. A prototype 12-bit second order MASH ΔΣ modulator designed in 65 nm CMOS technology based on this study achieves 9 GHz operation at 1 V supply.

    Place, publisher, year, edition, pages
    IEEE, 2013
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-120304 (URN)10.1109/NORCHIP.2013.6702009 (DOI)978-1-4799-1647-4 (ISBN)
    Conference
    IEEE NORCHIP Conference 2013, 11-12 November, Vilnius , Lithuania
    Available from: 2015-07-27 Created: 2015-07-27 Last updated: 2019-09-05Bibliographically approved
    5. Timing challenges in high-speed interleaved ΔΣ DACs
    Open this publication in new window or tab >>Timing challenges in high-speed interleaved ΔΣ DACs
    2014 (English)In: 14th International Symposium on Integrated Circuits (ISIC), 2014, IEEE , 2014, p. 46-49Conference paper, Published paper (Refereed)
    Abstract [en]

    Time-interleaved ΔΣ DACs have the potential for wideband and high-speed operation. Their SNR is limited by the timing skew between the output delays of the channels to the output. In a two-channel interleaved ΔΣ DAC, the channel skew arises from the duty cycle error in the half sample rate clock. The effects of timing skew error can be mitigated by hold interleaving, digital pre-filtering or compensation in the form of analog post-correction or digital pre-correction. This paper presents a comparative study of these techniques for two-channel interleaving and the trade-offs are investigated. First order FIR pre-filtering is found to be a suitable solution with a moderate DAC matching penalty of one bit. Higher order pre-filtering achieves a near immunity to timing skew at the cost of higher matching penalty. Correction techniques are found to be less effective than pre-filtering and not well suited for high-speed implementation.

    Place, publisher, year, edition, pages
    IEEE, 2014
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-114736 (URN)10.1109/ISICIR.2014.7029513 (DOI)
    Conference
    14th International Symposium on Integrated Circuits (ISIC), 10-12 December, Singapore 2014
    Available from: 2015-03-03 Created: 2015-03-03 Last updated: 2019-09-05Bibliographically approved
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  • 277.
    Bhide, Ameya
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A 11-GS/s 1.1-GHz Bandwidth Interleaved ΔΣ DAC for 60-GHz Radio in 65-nm CMOS2015In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, E-ISSN 1558-173X, Vol. 50, no 10, p. 2306-2310Article in journal (Refereed)
    Abstract [en]

    This work presents an 11 GS/s 1.1 GHz bandwidth interleaved ΔΣ DAC in 65 nm CMOS for the 60 GHz radio baseband. The high sample rate is achieved by using a two-channel interleaved MASH 1–1 architecture with a 4 bit output resulting in a predominantly digital DAC with only 15 analog current cells. Two-channel interleaving allows the use of a single clock for the logic and the multiplexing which requires each channel to operate at half sampling rate of 5.5 GHz. To enable this, a look-ahead technique is proposed that decouples the two channels within the integrator feedback path thereby improving the speed as compared to conventional loop-unrolling. Measurement results show that the ΔΣ DAC achieves a 53 dB SFDR, -49 dBc IM3 and 39 dB SNDR within a 1.1 GHz bandwidth while consuming 117 mW from 1 V digital/1.2 V analog supplies. Furthermore, the proposed ΔΣ DAC can satisfy the spectral mask of the IEEE 802.11ad WiGig standard with a second order reconstruction filter.

    Download full text (pdf)
    fulltext
  • 278.
    Bialek, Lukasz
    et al.
    Institute of Informatics, University of Warsaw, Poland.
    Dunin-Keplicz, Barbara
    Institute of Informatics, University of Warsaw, Poland.
    Szalas, Andrzej
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems. Linköping University, Faculty of Science & Engineering.
    Towards a Paraconsistent Approach to Actions in Distributed Information-Rich Environments2018In: Intelligent Distributed Computing XI / [ed] Mirjana Ivanović, Costin Bădică, Jürgen Dix, Zoran Jovanović, Michele Malgeri, Miloš Savić, Cham: Springer, 2018, Vol. 737, p. 49-60Conference paper (Refereed)
    Abstract [en]

    The paper introduces ActLog, a rule-based language capable of specifying actions paraconsistently. ActLog is an extension of 4QL&#xA0;Bel&#xA0;" role="presentation"> Bel , a rule-based language for reasoning with paraconsistent and paracomplete belief bases and belief structures. Actions considered in the paper act on belief bases rather than states represented as sets of ground literals. Each belief base stores multiple world representations which can be though of as a representation of possible states. In this context ActLog’s action may be then seen as a method of transforming one belief base into another. In contrast to other approaches, ActLog permits to execute actions even if the underlying belief base state is partial or inconsistent. Finally, the framework introduced in this paper is tractable.

  • 279.
    Bianzino, Aruna Prem
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Cooperative proxies: Optimally trading energy and quality of service in mobile devices2014In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 75, no Part A, p. 297-312Article in journal (Refereed)
    Abstract [en]

    This work studies the energy and quality of service (QoS) trade-off in the context of mobile devices with two communication interfaces (a high energy and a low energy interface). We propose an optimisation scheme during underload scenarios where proxy groups are dynamically formed exploiting both interfaces. The scheme integrates a reward mechanism that compensates a proxy while carrying other group members’ traffic, and deals with churn (joining and leaving of nodes) in a cell area. For traffic flows that approximate knowledge about current services we show that the scheme can achieve energy savings of 60% for all mobile nodes as whole. We also demonstrate the impact on disruption-sensitive flows as a function of the traffic mix, and that the use of rewards for selection of proxies is a fair mechanism in the long term.

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  • 280.
    Bildsten, Caroline
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Application Whitelisting: Smartphones in High Security Environments2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, smartphones are in widespread use by consumers, commercial companies and government authorities. Unfortunately, there are many examples of applications carrying out malicious activities, such as stealing information or subscribing to premium-rate services. In this thesis work, a novel application whitelisting process (AWP) is proposed. It defines processes for application security audits and whitelisting i.e. methods on how to classify, evaluate and test a given application to make sure that it with a level of assurance does not have malicious intentions. In a risk analysis of users in high security environments, the results showed that confidentiality and availability is the top most important security aspects to protect in this environment. The applications in the whitelisting process should therefore be tested for known malware and adware as well as permissions that can be used to send private information to remote servers. Additionally, testing should also be carried out for information leakage through intents and content resolvers. Because whitelisting is locking down the freedom and usability that comes with a smartphone, three different leveled whitelists are proposed to satisfy users and organizations with different security needs. A prototype was developed to prove the overall usability of the design. The result of scanning 200 applications from Google Play showed that 12% of all applications can be placed in the highest leveled whitelist. The results also suggest that 17.5 % of all applications on Google Play are malware or potentially unwanted applications. The results points to that using this novel whitelisting process, about 30% of all applications can be automated into whitelists and will not need manual analysis.

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    Application Whitelisting
  • 281.
    Binggeli, Alexander
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Partialevaluering: Specialisering av program  Utformning av en laboration2012Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Partialevaluering av program är ett intressant ämne både för att optimera programmen men även för möjligheterna att kompilera program med en interpretator.

    Denna rapport beskriver hur laborationerna i kursen Data och Programstrukturer på Linköpings Universitet, som är helt baserad på Abelson & Sussmans bok Structure and Interpretation of Computer Programs kan utökas så att den även går igenom partialevaluering. Som grund i laborationsunderlaget ligger en enkel partialevaluator för en delmängd av det funktionella språket Scheme som utvecklas för underlaget.

    Rapporten består i huvudsak av tre delar, i början introduceras läsaren till partialevaluering. Vi förklarar hur man av ett generellt program och viss känd information vill skapa ett nytt specialiserat program. Två vanliga metoder att göra partialevaluering på beskrivs men i första hand fokuserar rapporten på den metod som implementerats, nämligen offline metoden. Specialisering av ett program med en offline partialevaluator börjar med en analys av programmet som sedan specialiseras. Vi går igenom varje steg i analysen och specialiseringen innan implementationen introduceras.

    I den andra delen av rapporten tittar vi närmre på den implementation som kommer användas I laborationsuppgifterna. Genom att beskriva språket som specialiseras och titta på kod för de funktioner som är intressanta förklaras hur partialevaluatorn fungerar.

    Tillslut presenteras fem förslag på uppgifter kring några ämnen och problem som passar I laborationskursen. Uppgifterna försöker följa en liknande ordning som tidigare uppgifter i kursen. Vi börjar med en uppgift där man testar partialevaluatorn och undersöker resultatet av specialisering. Sedan följer tre uppgifter som tittar på hur funktionaliteten i partialevaluatorn kan utökas. Den sista uppgiften fokuserar på hur man kan kompilera ett mönster till en mönstermatchare med en partialevaluator.

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  • 282.
    Bjelkstål, Per Anders
    Linköping University, Department of Computer and Information Science.
    Implementering av ett kortbetalningssystem2008Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [sv]

    I ett kortbetalningssystem såsom Visa International Service Association (Visa) finns det fem stycken tongivande parter: kortinlösaren; kortutgivaren; kortinnehavaren; säljföretaget och Payment Service Provider (PSP). Ett säljföretag som låter sina kunder betala för varor och tjänster på sin webbplats skickar kundernas kortnummer krypterat till en PSP som vidarebefodrar dessa till VisaNet som är dataknutpunkten i Visa. VisaNet söker med hjälp utav kortnumret upp den bank som har utgivit kortet och efterfrågar samma bank om en transaktion får ske från kortet. VisaNet får ett svar som vidarebefordras vidare tillbaka till säljföretaget som sedermera även får sina pengar överförda till sitt konto från kundens konto.

    Uppdragsgivaren till detta examensarbete skall utveckla ett helt eget system och bli sin egen PSP utifall uppdragsgivaren beräknar att mer än 1,3 miljoner stycken kortbetalningar kommer att ske genom uppdragsgivarens kortbetalningssystem per år. När detta examensarbete utfördes uppskattades antalet kortbetalningar per år inte till denna siffra och rapportförfattaren utvecklade därför ett korbetalningssystem med hjälp utav en befintlig PSP.

    Kortbetalningssystemets kärna är ett API som andra systemutvecklare hos uppdragsgivaren kan anropa. API:t har ett antal funktioner såsom att utföra en kortbetalning, reservera en kortbetalning eller att avbryta en reserverad kortbetalning. Rapportförfattaren har även utvecklat ett grafiskt övervaknings- och administrationsgränssnitt för att kunna övervaka de kortbetalningar som sker samt enkelt kunna felsöka fel som uppstår i systemet.

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  • 283.
    Bjerre, Johan
    The Institute of Technology, Faculty of Arts and Sciences, Linköping University, Department of Computer and Information Science.
    Load management for a telecom charging system2008Independent thesis Advanced level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    There are a huge number of customers using Ericsson’s prepaid telecom charging system. This means that even the smallest optimization done in its management of load results in a big win when considering time and CPU usage. Ericsson wishes therefore to learn about how the load management can be improved considering speed, i.e. faster response to load changes.

    In this thesis work two subsystems of the prepaid telecom system are modeled. The first subsystem treats and prepares the telecom activity before it enters the second subsystem which checks if there is coverage for the action that the telecom activity asks for to be performed. A model which is an emulation of the subsystems is built using c++. It captures the timing of the real system not the logic or function. The c++ approach is compared to a Matlab approach which runs much slower in simulation. In addition, the model enables full view of the queue sizes and the rejects made by the regulator.

    Verification has been performed with self generated data based on synthetic test cases. Verification and analysis show that the model captures the intended behavior of load management. Information about different software parameters and its influence on the output is obtained. Different scenarios are tested and the outcome discussed.

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  • 284.
    Bjurenfalk, Jonatan
    et al.
    Linköping University, Department of Computer and Information Science.
    Cedighi, Saam
    Linköping University, Department of Computer and Information Science.
    Fröberg, Simon
    Linköping University, Department of Computer and Information Science.
    Holmström, Oskar
    Linköping University, Department of Computer and Information Science.
    Hubertsson, Oscar
    Linköping University, Department of Computer and Information Science.
    Leth, Axel
    Linköping University, Department of Computer and Information Science.
    Olsson, Linda
    Linköping University, Department of Computer and Information Science.
    Ågren, Sara
    Linköping University, Department of Computer and Information Science.
    KomUt: Utveckling av en samåkningsplattform för företagsanställda2018Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    In our society there is an increased awareness of environmental impact and reducing greenhouse gas emissions. An influencing factor is transport in passenger cars to and from work. In order to increase the utilization rate of passenger cars and thereby reduce environmental impact, a possible solution is to carpool. The purpose of the project was to create a web application to help those who want to carpool. To be effective and interesting to users such a web application needs to be useful and easy to navigate, as supported in previous surveys. The report’s issue is therefore how a carpooling web application, for companies and their employees, is designed and implemented to make it useful with regard to navigability.

    The attempt to answer the issue was initiated by finding relevant theory of navigabil- ity and usability. After that a market survey was conducted, to better understand the needs of the target group, and a prototype was developed based on the found theory. User stories were developed to define the application’s functionality and the development of the web application took place in parallel with iterative user tests, where feedback from the tests was implemented.

    At the end of the project, the final result and each user test were analyzed to compare users’ response to current theory and by answering the issue of the report. Based on the results of the tests, given the theoretical framework, it was shown that two out of four test subjects got lost in the web application. The test subjects were struggling to get through the buying process. They had insufficient understanding of what happens when placing a trip in the cart, that the trips are booked inside the shopping cart and that the payment of completed trips are found on the profile page. Reasons for the result may be due to both the weaknesses of the web application navigability or the characteristics of the test subjects. Despite this the web application was considered useful in accordance with the System Usability Test performed. In its entirety, the web application can be assessed as useful, though it can not be considered to meet the theoretical requirements for navigability.

    The conclusion is that a navigable web application can be developed by allowing users to effectively find the most important features of the web application. This can be imple- mented with a distinct navigation bar, visual indications for links, information boxes, a natural flow for the user through the page structure, and that the user can get through it with few steps. This should be specifically applied to the buying process, which is central to a consumer web application, to reduce perceived complexity and to be useful and navigable to the user. In order for the web application to be perceived as useful, it should contain the basic functionality requirements expected of a carpooling service. These are being able to register oneself, find a trip, create a trip, find information about pricing and to be able to remove a trip.

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    TDDD83 - Kandidatrapport - Kandidatgrupp 7
  • 285.
    Bjäreland, Marcus
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Model-based execution monitoring2001Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The task of monitoring the execution of a software-based controller in order to detect, classify, and recover from discrepancies between the actual effects of control actions and the effects predicted by a model, is the topic of this thesis. Model-based execution monitoring is proposed as a technique for increasing the safety and optimality of operation of large and complex industrial process controllers, and of controllers operating in complex and unpredictable environments (such as unmanned aerial vehicles).

    In this thesis we study various aspects of model-based execution monitoring, including the following:

    The relation between previous approaches to execution monitoring in Control Theory, Artificial Intelligence and Computer Science is studied and a common conceptual framework for design and analysis is proposed.

    An existing execution monitoring paradigm, ontological control, is generalized and extended. We also present a prototype implementation of ontological control with a first set of experimental results where the prototype is applied to an actual industrial process control system: The ABB STRESSOMETER cold mill flatness control system.

    A second execution monitoring paradigm, stability-based execution monitoring, is introduced, inspired by the vast amount of work on the "stability" notion in Control Theory and Computer Science.

    Finally, the two paradigms are applied in two different frameworks. First, in the "hybrid automata" framework, which is a state-of-the-art formal modeling framework for hybrid (that is, discrete+continuous) systems, and secondly, in the logical framework of GOLOG and the Situation Calculus. 

  • 286.
    Björk, Linus
    Linköping University, Department of Computer and Information Science.
    Avancerad webbteknologi i mobila webbläsare2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The web develops fast and web applications are getting more advanced. At the same time the mobile browsers develop at a rapid pace. However, it still differs a lot between a mobile browser and a standard web browser. You also interact with a mobile phone in a different way than what you do with a computer. This thesis examines whether it is possible to create advanced web applications that by utilizing the latest web technologies can replace ordinary mobile applications.

    The investigation is done by creating a lightweight version of a phone application, Mobile Documents on Symbian S60, which is an application that manages documents, emails and attachments.

    The development is done in Google Web Toolkit and technologies such as AJAX and Comet are both used. As the number of different types of phones with touch screens is very large the investigation only will target a small number of phones running web browsers as Mobile Safari, microB and Android Browser.

    The conclusions of this report is that the JavaScript support of today's browsers is enough to run advanced web applications. However, it differs a lot between browsers and the main problem is to create a functional user interface that works equally well on all phones and with all the different interaction possibilities that a mobile phone gives.

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    Avancerad webbteknologi i mobila webbläsare
  • 287.
    Björklund, Rebecka
    Linköping University, Department of Computer and Information Science.
    Implementation och jämförelse av ordnade associativa arrayer2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har som syfte att titta på om strukturer, så som van Emde Boas och y-fastträd är snabbare än en standardstruktur som binärt trie på att göra IP-uppslagningar i routingtabeller vid vidarebefordring av paket i nätverk. Detta är en av de mest utförda operationerna i dag. Den utförs varje gång ett paket passerar en router och går ut på att hitta den mest lämpliga vägen för paketet att ta sig till värden. Det är i denna operation ett framtida problem kan uppkomma på grund av den ständigt ökande trafiken över nätverken. Att minska tiden för IP-uppslagning med hjälp av strukturerna van Emde Boas eller y-fast kan vara en dellösning för att undvika att routern blir en framtida flaskhals. Resultaten från java-implementationerna visar dock att varken van Emde Boas eller y-fastträd genererar ett bättre resultat än ett binärt trie, trots att uppslagning i dessa strukturer har lägre asymptotisk tidskomplexitet än uppslagning i ett binärt trie. Det finns olika anledningar till att det är så; ett är att de routingtabeller som används ej är tillräckligt stora för att van Emde Boas- eller y-faststrukturernas fördelar ska visas. En annan orsak är att fler minnesaccesser till minnet görs i dessa jämfört med det binära triet.

    En gräns som länge ifrågasatts är om datagenomströmningen för en router kan överstiga en gigabyte per sekund(GB/s) genom att endast ändra routerns mjukvara och köra denna på standardhårdvara. Detta examensarbete och flera andra arbeten visar att det går att öka datagenomströmningen med lämplig implementation av routingtabellerna och IP-uppslagning. Trots att van Emde Boas eller y-fastträdet inte är bättre än det binära triet i antalet uppslagningar per sekund, visar van Emde Boas träd och det binära triet att dataöverföring i GB/s är möjliga att göra i mjukvara.

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  • 288.
    Björklén, Simon
    Linköping University, Department of Computer and Information Science.
    Extending Modelica with High-Level Data Structures: Design and Implementation in OpenModelica2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Modelica is an equation-based object-oriented language (EOO). PELAB at Linköping University along with the OpenModelica development group, is developing a metamodeling extension, MetaModelica, to this language along with a compiler called the OpenModelica Compiler (OMC).

    The goal of this thesis was to analyze the compiler, extend it with union type support and then write a report about the extension with union types in particular and extension with high level data structures in general, to facilitate further development.

    The implementation made by this thesis was implemented with the goal of keeping the current structure intact and extending case-clauses where possible. The main parts of the extension is implemented by this thesis work but some parts concerning the pattern matching algorithms are still to be extended. The main goal of this is to bootstrap the OpenModelica Compiler, making it able to compile itself although this is still a goal for the future.

    With this thesis I also introduce some guidelines for implementing a new highlevel data structure into the compiler and which modules needs extension.

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  • 289.
    Björnsdotter, Malin
    et al.
    Institute of Neuroscience and Physiology, University of Gothenburg, Göteborg, Sweden.
    Nalin, Kajsa
    Centre of Interdisciplinary Research/Cognition/Information, University of Gothenburg, Göteborg, Sweden.
    Hansson, Lars-Erik
    Department of Surgery, Sahlgrenska University Hospital/Östra, Göteborg, Sweden.
    Malmgren, Helge
    Department of Philosophy, Linguistics and Theory of Science, University of Gothenburg, Göteborg, Sweden.
    Support Vector Machine Diagnosis of Acute Abdominal Pain2010In: Biomedical Engineering Systems and Technologies: International Joint Conference, BIOSTEC 2009 Porto, Portugal, January 14-17, 2009, Revised Selected Papers / [ed] Fred, Ana; Filipe, Joaquim; Gamboa, Hugo, Springer Berlin/Heidelberg, 2010, p. 347-355Chapter in book (Other academic)
    Abstract [en]

    This study explores the feasibility of a decision-support system for patients seeking care for acute abdominal pain, and, specifically the diagnosis of acute diverticulitis. We used a linear support vector machine (SVM) to separate diverticulitis from all other reported cases of abdominal pain and from the important differential diagnosis non-specific abdominal pain (NSAP). On a database containing 3337 patients, the SVM obtained results comparable to those of the doctors in separating diverticulitis or NSAP from the remaining diseases. The distinction between diverticulitis and NSAP was, however, substantially improved by the SVM. For this patient group, the doctors achieved a sensitivity of 0.714 and a specificity of 0.963. When adjusted to the physicians’ results, the SVM sensitivity/specificity was higher at 0.714/0.985 and 0.786/0.963 respectively. Age was found as the most important discriminative variable, closely followed by C-reactive protein level and lower left side pain.

  • 290.
    Bladh, Theodor
    et al.
    Linköping University, Department of Computer and Information Science.
    Stridh, Christoffer
    Linköping University, Department of Computer and Information Science.
    Algorithmically Generating Bugs2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    A method to quickly produce large sets ofdifferent textures of insects (bugs) wasimplemented. The textures were procedurallygenerated in a 3D-modelling tool and thenrendered for use in a 2D-motion-based game.The resulting textures were evaluatedregarding quality and distinguishability. Noparticular features were found to be favouredover others, except some features being betterthan no features at all. Distinguishing betweengenerated textures was found to be a trivial taskfor most users.

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  • 291.
    Blom, Rolf
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    On Pure and Related Ciphers1981Report (Other academic)
    Abstract [en]

    It is possible to formulate several properties of a cipher that can be said to make the cipher homogeneous with respect to the key, i.e. whatever key used different aspects of the enciphering, deciphering and decrypting processes will be independent of the key choice. We investigate such properties and define a property called key homogeneity. The class of key homogeneous ciphers is shown to include the class of pure ciphers. The algebraic properties of pure ciphers are analyzed in detail. Finally the connection between pure ciphers and key homogeneous ciphers is investigated.

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    On Pure and Related Ciphers
  • 292.
    Blom, Rolf
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Fåk, Viiveke
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Ingemarsson, Ingemar
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Data Network Security: Part I Problem Survey and Model1977Report (Other academic)
    Abstract [en]

    Data encryption and related methods may be used to preserve information security i n a data network. Here information security is defined as the degree to which the destruction, change or loss of information is presented. Information is defined as the content of the message represented by the data. The information in a block of data is unchanged if the intended result of the transmission of the block is obtained. This means for example that the original message reaches the correct destination where it is interpreted as intended. Undisturbed information does not, in general, require un disturbed data.

    The network is supposed to be a public network, accessed by many different users. We are interested in a well defined group of users who are communicating mainly among themselves. Different groups, however, are also allowed to communicate in a well defined manner. The logical structure of the communication within a group is star-shaped. The information communicated within the groups hall be protected against threats from other users of the network, from illegitimate users (wiretappers etc) and from members in the group. The structure of the threats is described in section 3 of this paper.

    The network itself and the requirement it imposes are supposed to be unchanged. Encryption and decryption are taking place outside the network. The encrypted data shall comply with the requirements of the network. The communication process in the group consists of time-limited messages which are essentially transmitted from one point to another in the network. This is the basis for the model of the communication which is described in section 4. The model, although simple, enables us to structure the problems in connection with encryption/decryption. This is done in section 5 and 6. The purpose of the paper is to form a basis for synthesis of security measures by means on cryptological methods. The analysis is general enough to be applied to any data network and any type of user group.

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    Data Network Security: Part I Problem Survey and Model
  • 293.
    Blomkvist, Johan
    et al.
    Linköping University, Department of Computer and Information Science, MDI - Interaction and Service Design Research Group. Linköping University, The Institute of Technology.
    Holmlid, Stefan
    Linköping University, Department of Computer and Information Science, MDI - Interaction and Service Design Research Group. Linköping University, The Institute of Technology.
    Examplars in Service Design2009In: First Nordic Conference on Service Design, Linköping University Electronic Press , 2009Conference paper (Refereed)
    Abstract [en]

    Exemplars play an important role in applied service design but are largely overlooked in academic literature. So far; most design research in other fields has concerned how surface properties of exemplars are incorporated in the current design; but services are different from most other design disciplines in regard to material. To expand the understanding of how exemplars matter to service design; material from recordings and observations of design meetings have been analysed. We observed a pattern that exemplars; in this case; were introduced in communication in the format of micro-narratives that express emotional impact of service elements. This study shows that exemplars in the form of micro-narratives are retrieved in design discourse primarily from gathered data; common reference points; and personal experiences. They contribute to the collective understanding of the service concept and support the alignment of the service offering with customer expectations.

  • 294.
    Blommendahl, Simon
    Linköping University, Department of Computer and Information Science.
    An analysis of API usability and Azure API management2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today’s computer environments the systems are getting bigger and more complex for each day that passes by. The motivating factor for this is that the customer wants to achieve more and more with their computer systems than before. The only way to really solve this task is to use even more APIs (Application program interfaces) in their systems.    

    When using more APIs in a system, there is a chance that the specific system provides the same type of API twice, which of course, is a waste of storage and resources. In addition, the more APIs a system contains, the bigger the risk is for mismanagement of these APIs. In the worst case, this can result in security breaches or data leaks. 

    This thesis investigates specific APIs provided for a customer of Sigma IT Consulting. The aim is to evaluate and organize the APIs according to their usability criteria. The main focus of the evaluation is the available documentation which will be evaluated by a questionnaire survey distributed to senior software developers at Sigma IT Consulting in Växjö.

    Conclusions will then be drawn depending on the result from the survey, and we can then see if Azure API management (which is a service to make a system more user – friendly) is accurate in its way of organizing with the API usability as the main focus!

    Unfortunately, Azure API management did not have any possibility what so ever to customize the API placement in a system, and the only way the APIs are organized is in alphabetical order. Therefore, a prototype with even more sorting functionality than Azure API management will also be presented in this thesis.

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  • 295.
    Blomquist, Linus
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Hybrid klient till molntjänst2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    My thesis work was to build a hybrid client that uses the same graphical interface as Xcerions current webbclient. The client shall be able to run without any usage of a web browser and it shall instead be an installed program on the users computer. The source-code of Cloudtop, written in Javascript, now communicates with code written in C++ by using a bridge that bind these languages together. XSLT-requests that is used to be handled by the web browser is now handled by the code written in C++ . The program is also prepared to be extended by functionality to handle offline requests from the user. After such implementation the user no longer is going to need constant internet coverage. The service work both synchronous and asynchronous to make it faster and more stable at heavy calculations.

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  • 296. Order onlineBuy this publication >>
    Blomqvist, Eva
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Semi-automatic Ontology Construction based on Patterns2009Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis aims to improve the ontology engineering process, by providing better semiautomatic support for constructing ontologies and introducing knowledge reuse through ontology patterns. The thesis introduces a typology of patterns, a general framework of pattern-based semi-automatic ontology construction called OntoCase, and provides a set of methods to solve some specific tasks within this framework. Experimental results indicate some benefits and drawbacks of both ontology patterns, in general, and semi-automatic ontology engineering using patterns, the OntoCase framework, in particular.

    The general setting of this thesis is the field of information logistics, which focuses on how to provide the right information at the right moment in time to the right person or organisation, sent through the right medium. The thesis focuses on constructing enterprise ontologies to be used for structuring and retrieving information related to a certain enterprise. This means that the ontologies are quite 'light weight' in terms of logical complexity and expressiveness.

    Applying ontology content design patterns within semi-automatic ontology construction, i.e. ontology learning, is a novel approach. The main contributions of this thesis are a typology of patterns together with a pattern catalogue, an overall framework for semi-automatic patternbased ontology construction, specific methods for solving partial problems within this framework, and evaluation results showing the characteristics of ontologies constructed semiautomatically based on patterns. Results show that it is possible to improve the results of typical existing ontology learning methods by selecting and reusing patterns. OntoCase is able to introduce a general top-structure to the ontologies, and by exploiting background knowledge, the ontology is given a richer structure than when patterns are not applied.

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    Semi-automatic Ontology Construction
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  • 297.
    Blomqvist, Eva
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    The use of Semantic Web technologies for decision support – a survey2014In: Semantic Web, ISSN 1570-0844, E-ISSN 2210-4968, Vol. 5, no 3, p. 177-201Article in journal (Refereed)
    Abstract [en]

    The Semantic Web shares many goals with Decision Support Systems (DSS), e.g., being able to precisely interpret information, in order to deliver relevant, reliable and accurate information to a user when and where it is needed. DSS have in addition more specific goals, since the information need is targeted towards making a particular decision, e.g., making a plan or reacting to a certain situation. When surveying DSS literature, we discover applications ranging from Business Intelligence, via general purpose social networking and collaboration support, Information Retrieval and Knowledge Management, to situation awareness, emergency management, and simulation systems. The unifying element is primarily the purpose of the systems, and their focus on information management and provision, rather than the specific technologies they employ to reach these goals. Semantic Web technologies have been used in DSS during the past decade to solve a number of different tasks, such as information integration and sharing, web service annotation and discovery, and knowledge representation and reasoning. In this survey article, we present the results of a structured literature survey of Semantic Web technologies in DSS, together with the results of interviews with DSS researchers and developers both in industry and research organizations outside the university. The literature survey has been conducted using a structured method, where papers are selected from the publisher databases of some of the most prominent conferences and journals in both fields (Semantic Web and DSS), based on sets of relevant keywords representing the intersection of the two fields. Our main contribution is to analyze the landscape of semantic technologies in DSS, and provide an overview of current research as well as open research areas, trends and new directions. An added value is the conclusions drawn from interviews with DSS practitioners, which give an additional perspective on the potential of Semantic Web technologies in this field; including scenarios for DSS, and requirements for Semantic Web technologies that may attempt to support those scenarios.

  • 298.
    Blomqvist, Eva
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Gangemi, AldoISTC-CNR.Hammar, KarlJönköping University.Suárez-Figueroa, María del Carmen
    Proceedings of the 3rd Workshop on Ontology Patterns, Boston, USA, November 12, 20122012Conference proceedings (editor) (Other academic)
  • 299.
    Blomqvist, Eva
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Groza, Tudor
    Proceedings of the ISWC 2013 Posters & Demonstrations Track, Sydney, Australia, October 23, 20132013Conference proceedings (editor) (Other academic)
  • 300.
    Blomqvist, Eva
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Hammar, Karl
    Computer Science and Informatics, School of Engineering, Jönköping University, Sweden.
    Presutti, Valentina
    Institute of Cognitive Sciences and Technologies, Italy.
    Engineering Ontologies with Patterns: The eXtreme Design Methodology2016In: Ontology Engineering with Ontology Design Patterns: Foundations and Applications / [ed] Pascal Hitzler, Aldo Gangemi, Krzysztof Janowicz, Adila Krisnadhi, Valentina Presutti, IOS Press, 2016, p. 23-50Chapter in book (Other academic)
    Abstract [en]

    When using Ontology Design Patterns (ODPs) for modelling new parts of an ontology, i.e., new ontology modules, or even an entire ontology from scratch, ODPs can be used both as inspiration for different modelling solutions, as well as concrete templates or even “building blocks” reused directly in the new solution. This chapter discusses how ODPs, and in particular Content ODPs

    In fact, throughout this chapter when mentioning ODPs, this mainly refers to Content ODPs if not specified further.

    , can be used in ontology engineering. In particular, a specific ontology engineering methodology is presented, which was originally developed for supporting ODP use. However, this methodology, the eXtreme Design (XD), also has some characteristics that set it apart from most other ontology engineering methodologies, and which may be interesting to consider regardless of how much emphasis is put on the ODP usage. Towards the end of the chapter some XD use cases are also reported and discussed, as well as lessons learned from applying XD. The chapter is concluded through a summary and discussion about future work.

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