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  • 201.
    Karlsson, Axel
    et al.
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Wångblad, Christian
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    En kvantitativ jämförelse av opensource-navigeringsprogram med OpenStreetMap som kartdatabas2018Självständigt arbete på grundnivå (högskoleexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Under detta arbete testades och utvärderades navigeringsverktyg mot varandra för att sedan se om de, tillsammans med kartsystemet OpenStreetMap, kunde fungera som substitut till programmet Google Maps och användas för att navigera vid en rutt. Navigeringssystemen som jämfördes hade alla öppen källkod och det gick att sätta upp och köra lokalt på en personlig dator med hjälp av stickprovsdata för att navigera i olika delar av världen.

  • 202.
    Karresand, Martin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    File Type Identification of Data Fragments by Their Binary Structure2006Ingår i: IEEE Systems, Man and Cybernetics Society Information Assurance Workshop,2006, Piscataway, NJ, USA: IEEE , 2006, s. 140-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Rapidly gaining information superiority is vital when fighting an enemy, but current computer forensics tools, which require file headers or a working file system to function, do not enable us to quickly map out the contents of corrupted hard disks or other fragmented storage media found at crime scenes. The lack of proper tools slows down the hunt for information, which would otherwise help in gaining the upper hand against IT based perpetrators. To address this problem, this paper presents an algorithm which allows categorization of data fragments based solely on their structure, without the need for any meta data. The algorithm is based on measuring the rate of change of the byte contents of digital media and extends the byte frequency distribution based Oscar method presented in an earlier paper. The evaluation of the new method shows a detection rate of 99.2 %, without generating any false positives, when used to scan for JPEG data. The slowest implementation of the algorithm scans a 72.2 MB file in approximately 2.5 seconds and scales linearly.

  • 203.
    Karresand, Martin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Oscar - File Type and Camera Identification Using the Structure of Binary Data Fragments2006Ingår i: First Conference on Advances in Computer Security and Forensics, ACSF 2006 / [ed] John Haggerty, Madjid Merabti, Liverpool, UK: School of Computing and Mathematical Sciences, John Moores University , 2006, s. 11-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mapping out the contents of fragmented storage media is hard if the file system has been corrupted, especially as the current forensic tools rely on meta information to do their job. If it were possible to find all fragments belonging to a certain file type, it might also be possible to recover a lost file. The Oscar method identifies the file type of data fragments based on their structure. This paper presents an improvement of the Oscar method. The new version is built on using 2-grams to create a model of different file types. The method is evaluated for JPEG, Windows executables, and zip files, reaching a 100% detection rate with 0.12% false positives for JPEG. We also use the method to identify the camera make used to capture a JPEG picture from a fragment of the picture.

  • 204.
    Karresand, Martin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Oscar - File Type Identification of Binary Data in Disk Clusters and RAM Pages2006Ingår i: IFIP TC-11 International Information Security Conference SEC,2006, New York, NY, USA: Springer , 2006, s. 413-Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a method, called Oscar, for determining the probable file type of binary data fragments. The Oscar method is based on building models, called centroids, of the mean and standard deviation of the byte frequency distribution of different file types. A weighted quadratic distance metric is then used to measure the distance between the centroid and sample data fragments. If the distance falls below a threshold, the sample is categorized as probably belonging to the modelled file type. Oscar is tested using JPEG pictures and is shown to give a high categorization accuracy, i.e. high detection rate and low false positives rate. By using a practical example we demonstrate how to use the Oscar method to prove the existence of known pictures based on fragments of them found in RAM and the swap partition of a computer.

  • 205.
    Karresand, Martin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Oscar — Using Byte Pairs to Find File Type and Camera Make of Data Fragments2007Ingår i: EC2ND 2006: Proceedings of the Second European Conference on Computer Network Defence, in conjunction with the First Workshop on Digital Forensics and Incident Analysis Faculty of Advanced Technology, University of Glamorgan, Wales, UK / [ed] Andrew Blyth, Iain Sutherland, Springer London, 2007, s. 85-94Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Mapping out the contents of fragmented storage media is hard if the file system has been corrupted, especially as the current forensic tools rely on meta information to do their job. If it was possible to find all fragments belonging to a certain file type, it would also be possible to recover a lost file. Such a tool could for example be used in the hunt for child pornography. The Oscar method identifies the file type of data fragments based solely on statistics calculated from their structure. The method does not need any meta data to work. We have previously used the byte frequency distribution and the rate of change between consecutive bytes as basis for the statistics, as well as calculating the 2-gram frequency distribution to create a model of different file types. This paper present a variant of the 2-gram method, in that it uses a dynamic smoothing factor. In this way we take the amount of data used to create the centroid into consideration. A previous experiment on file type identification is extended with .mp3 files reaching a detection rate of 76\% with a false positives rate of 0.4\%. We also use the method to identify the camera make used to capture a .jpg picture from a fragment of the picture. The result shows that we can clearly separate a picture fragment coming from a Fuji or Olympus cameras from a fragment of a picture of the other camera makes used in our test.

  • 206.
    Karresand, Martin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Reassembly of Fragmented JPEG Images Containing Restart Markers2008Ingår i: Proceedings - 4th Annual European Conference on Computer Network Defense, EC2ND 2008, Los Alamitos, CA, USA: IEEE Computer Society , 2008, s. 25-32Konferensbidrag (Refereegranskat)
    Abstract [en]

    A fragmented JPEG image is currently not possible to reassemble without knowing the ordering of the fragments. This is a problem for the police when they search for illegal digital images. This paper presents a method to reassemble fragmented JPEG images containing restart markers. Empirical evaluations show that it is possible to reassemble images taken from a set containing fragments of several images.

  • 207.
    Keivani, Omid
    et al.
    Wichita State University, USA.
    Peña, Jose M.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Uni- and Multi-Dimensional Clustering Via Bayesian Networks2016Ingår i: Unsupervised Learning Algorithms / [ed] Emre Celebi, Kemal Aydin, Cham: Springer, 2016, s. 163-192Kapitel i bok, del av antologi (Refereegranskat)
  • 208.
    Khodari, Mohammad
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Decentralized firmware attestation for in-vehicle networks2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Today's vehicles are controlled by several so called electronic control units (ECUs). ECUs can be seen as small computers that work together in order to perform a common task. They control everything from critical tasks such as engine control to less critical functionality such as window control. The most prominent trend that can be observed today is the development of self-driving functionality. Due to inherent complexity of self-driving functionality, ECUs are becoming more dependent on each other. A fundamental problem in today's vehicles is that there does not exist any efficient way of achieving trust in the vehicle's internal-network. How can ECUs be assured that the output of other ECUs can be trusted? If an ECU produces the wrong output when the vehicle is in autonomous mode it can lead to the vehicle performing unsafe actions and risking the lives of the passengers and driver.

    In this thesis we evaluate different already established firmware attestation solutions for achieving trust in a decentralized network. Furthermore, three new firmware attestation solutions specially tailored for the automotive domain are proposed. We demonstrate that all the found existing solutions have a fundamental flaw, they all have a single point of failure. Meaning that if you eliminate the correct node, the entire attestation process stops functioning. Thus, a new more robust solution specially tailored for the automotive domain needed to be developed. Three different consistency verification mechanisms were designed. One parallel solution, one serial solution and one merkle-tree solution. Two of the three proposed solutions, the parallel solution and serial solution, were implemented and assessed. Two tests were conducted, a detection performance test and a timing performance test.

    By assessing the detection performance test and timing performance test of the serial and parallel solutions, it was concluded that the parallel solution showed a significant improvement in both stability and performance over the serial solution.

  • 209.
    Klingström, Tomas
    et al.
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Soldatova, Larissa
    Aberystwyth University, UK.
    Stevens, Robert
    Universtity of Manchester, UK.
    Roos, T. Erik
    University of Groningen, The Netherlands.
    Swertz, Morris A.
    University of Groningen, The Netherlands.
    Müller, Kristian M.
    University of Potsdam, Germany.
    Kalas, Matus
    University of Bergen, Norway.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Taussig, Michael J.
    Babraham Bioscience Technologies, Cambridge, UK.
    Litton, Jan-Eric
    Karolinska Institutet, Stockholm, Sweden.
    Landegren, Ulf
    Uppsala University, Sweden.
    Bongcam-Rudloff, Erik
    Swedish University of Agricultural Sciences and Uppsala University, Sweden.
    Workshop on laboratory protocol standards for the molecular methods database2013Ingår i: New Biotechnology, ISSN 1871-6784, E-ISSN 1876-4347, Vol. 30, nr 2, s. 109-113Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Management of data to produce scientific knowledge is a key challenge for biological research in the 21st century. Emerging high-throughput technologies allow life science researchers to produce big data at speeds and in amounts that were unthinkable just a few years ago. This places high demands on all aspects of the workflow: from data capture (including the experimental constraints of the experiment), analysis and preservation, to peer-reviewed publication of results. Failure to recognise the issues at each level can lead to serious conflicts and mistakes; research may then be compromised as a result of the publication of non-coherent protocols, or the misinterpretation of published data. In this report, we present the results from a workshop that was organised to create an ontological data-modelling framework for Laboratory Protocol Standards for the Molecular Methods Database (MolMeth). The workshop provided a set of short- and long-term goals for the MolMeth database, the most important being the decision to use the established EXACT description of biomedical ontologies as a starting point.

  • 210.
    Knuth, Magnus
    et al.
    Hasso Plattner Institute, University of PotsdamPotsdamGermany.
    Hartig, Olaf
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Scheduling Refresh Queries for Keeping Results from a SPARQL Endpoint Up-to-Date2016Ingår i: On the Move to Meaningful Internet Systems: OTM 2016 Conferences, 2016, Vol. 10033, s. 780-791Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many datasets change over time. As a consequence, long-running applications that cache and repeatedly use query results obtained from a SPARQL endpoint may resubmit the queries regularly to ensure up-to-dateness of the results. While this approach may be feasible if the number of such regular refresh queries is manageable, with an increasing number of applications adopting this approach, the SPARQL endpoint may become overloaded with such refresh queries. A more scalable approach would be to use a middle-ware component at which the applications register their queries and get notified with updated query results once the results have changed. Then, this middle-ware can schedule the repeated execution of the refresh queries without overloading the endpoint. In this paper, we study the problem of scheduling refresh queries for a large number of registered queries by assuming an overload-avoiding upper bound on the length of a regular time slot available for testing refresh queries. We investigate a variety of scheduling strategies and compare them experimentally in terms of time slots needed before they recognize changes and number of changes that they miss.

  • 211.
    Kodoth, Sruthi
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Jiménez Ramos, Juan Manuel
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Enhance user experience based on traffic in operator network2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 212.
    Korzun, Dmitry
    et al.
    Department of Computer Science, Petrozavodsk State University, Petrozavodsk, Russian Federation.
    Kuptsov, Dmitriy
    Helsinki Institute for Information Technology, Helsinki, Finland.
    Gurtov, Andrei
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    A comparative simulation study of deterministic and stochastic strategies for reduction of packet reordering in multipath data streaming2016Ingår i: International journal of simulation. Systems, Science and Technology, ISSN 1473-8031, E-ISSN 1473-804X, Vol. 17, nr 33, s. 10.1-10.8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multipath routing gains clear network performance advantages for data streaming in networked systems with high path diversity. The level of packet reordering, however, becomes higher: distant packets are reordered, the application performance is reduced due to head-of-line blocking at the destination, and a large resequencing buffer is needed for sorting incoming packets. In this paper, we study by simulation the stochastic compensation effect to reduce packet reordering. If a source randomizes packet scheduling into multiple paths of random transmission delays, then these two sides of randomness “quench” each other. We perform comparison experiments to test this hypothesis in various multipath configurations, focusing on deterministic vs. randomized strategies of packet scheduling. The experiments confirm the existence of the stochastic compensation effect and its considerable influence on the application performance. © 2016, UK Simulation Society. All rights reserved.

  • 213.
    Krishnamoorthi, Vengatanathan
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Efficient and Adaptive Content Delivery of Linear and Interactive Branched Videos2016Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Video streaming over the Internet has gained tremendous popularity over recent years and currently constitutes the majority of Internet traffic. The on-demand delivery of high quality video streaming has been enabled by a combination of consistent improvements in residential download speeds, HTTP-based Adaptive Streaming (HAS), extensive content caching, and the use of Content Distribution Networks (CDNs). However, as large-scale on-demand streaming is gaining popularity, several important questions and challenges remain unanswered, including determining how the infrastructure can best be leveraged to provide users with the best possible playback experience. In addition, it is important to develop new techniques and protocols that facilitate the next generation of streaming applications. Innovative services such as interactive branched streaming are gaining popularity and are expected to be the next big thing in on-demand entertainment.

    The major contributions of this thesis are in the area of efficient content delivery of video streams using HAS. To address the two challenges above, the work utilizes a combination of different methods and tools, ranging from real-world measurements, characterization of system performance, proof-of-concept implementations, protocol optimization, and evaluation under realistic environments. First, through careful experiments, we evaluate the performance impact and interaction of HAS clients with proxy caches. Having studied the typical interactions between HAS clients and caches, we then design and evaluate content-aware policies to be used by the proxy caches, which parse the client requests and prefetch the chunks that are most likely to be requested next. In addition, we also design cooperative policies in which clients and proxies share information about the playback session. Our evaluations reveal that, in general, the bottleneck location and network conditions play central roles in which policy choices are most advantageous, and the location of the bottlenecks significantly impact the relative performance differences between policy classes. We also show that careful design and policy selection is important when trying to enhance HAS performance using proxy assistance.

    Second, this thesis proposes, models, designs, and evaluates novel streaming applications such as interactive branched videos. In such videos, users can influence the content that is being shown to them. We design and evaluate careful prefetching policies that provides seamless playback even when the users defer their path choices to the last possible moment. We derive optimized prefetching policies using an optimization framework, design and implement effective buffer management techniques for seamless playback at branch points, and use parallel TCP connections to achieve efficient buffer workahead. Through performance evaluations, we show that our policies can effectively prefetch data of carefully adapted qualities along multiple alternative paths so to ensure seamless playback, offering users a pleasant viewing experience without playback interruptions.

  • 214.
    Krishnamoorthi, Vengatanathan
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Efficient HTTP-based Adaptive Streaming of Linear and Interactive Videos2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Online video streaming has gained tremendous popularity over recent years and currently constitutes the majority of Internet traffic. As large-scale on-demand streaming continues to gain popularity, several important questions and challenges remain unanswered. This thesis addresses open questions in the areas of efficient content delivery for HTTP-based Adaptive Streaming (HAS) from different perspectives (client, network and content provider) and in the design, implementation, and evaluation of interactive streaming applications over HAS.

    As streaming usage scales and new streaming services emerge, continuous improvements are required to both the infrastructure and the techniques used to deliver high-quality streams. In the context of Content Delivery Network (CDN) nodes or proxies, this thesis investigates the interaction between HAS clients and proxy caches. In particular, we propose and evaluate classes of content-aware and collaborative policies that take advantage of information that is already available, or share information among elements in the delivery chain, where all involved parties can benefit. Asides from the users’ playback experience, it is also important for content providers to minimize users’ startup times. We have designed and evaluated different classes of client-side policies that can prefetch data from the videos that the users are most likely to watch next, without negatively affecting the currently watched video. To help network providers to monitor and ensure that their customers enjoy good playback experiences, we have proposed and evaluated techniques that can be used to estimate clients’ current buffer conditions. Since several services today stream over HTTPS, our solution is adapted to predict client buffer conditions by only observing encrypted network-level traffic. Our solution allows the operator to identify clients with low-buffer conditions and implement policies that help avoid playback stalls.

    The emergence of HAS as the de facto standard for delivering streaming content also opens the door to use it to deliver the next generation of streaming services, such as various forms of interactive services. This class of services is gaining popularity and is expected to be the next big thing in entertainment. For the area of interactive streaming, this thesis proposes, models, designs, and evaluates novel streaming applications such as interactive branched videos and multi-video stream bundles. For these applications, we design and evaluate careful prefetching policies that provides seamless playback (without stalls or switching delay) even when interactive branched video viewers defer their choices to the last possible moment and when users switches between alternative streams within multi-video stream bundles. Using optimization frameworks, we design and implement effective buffer management techniques for seamless playback experiences and evaluate several tradeoffs using our policies.  

    Delarbeten
    1. Helping Hand or Hidden Hurdle: Proxy-assisted HTTP-based Adaptive Streaming Performance
    Öppna denna publikation i ny flik eller fönster >>Helping Hand or Hidden Hurdle: Proxy-assisted HTTP-based Adaptive Streaming Performance
    Visa övriga...
    2013 (Engelska)Ingår i: Modeling, Analysis & Simulation of Computer and Telecommunication Systems (MASCOTS), 2013 IEEE 21st International Symposium, IEEE , 2013, s. 182-191Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    HTTP-based Adaptive Streaming (HAS) has become a widely-used video delivery technology. Use of HTTP enables relatively easy firewall/NAT traversal and content caching. While caching is an important aspect of HAS, there is not much public research on the performance impact proxies and their policies have on HAS. In this paper we build an experimental framework using open source Squid proxies and the most recent Open Source Media Framework (OSMF). A range of content-aware policies can be implemented in the proxies and tested, while the player software can be instrumented to measure performance as seen at the client. Using this framework, the paper makes three main contributions. First, we present a scenario-based performance evaluation of the latest version of the OSMF player. Second, we quantify the benefits using different proxy-assisted solutions, including basic best effort policies and more advanced content quality aware prefetching policies. Finally, we present and evaluate a cooperative framework in which clients and proxies share information to improve performance. In general, the bottleneck location and network conditions play central roles in which policy choices are most advantageous, as they significantly impact the relative performance differences between policy classes. We conclude that careful design and policy selection is important when trying to enhance HAS performance using proxy assistance.

    Ort, förlag, år, upplaga, sidor
    IEEE, 2013
    Serie
    Modeling, Analysis, and Simulation of Com puter and Telecommunications Systems, ISSN 1526-7539
    Nyckelord
    HTTP-based adaptive streaming, Proxy assisted
    Nationell ämneskategori
    Datavetenskap (datalogi)
    Identifikatorer
    urn:nbn:se:liu:diva-105282 (URN)10.1109/MASCOTS.2013.26 (DOI)978-0-7695-5102-9 (ISBN)978-1-4799-1209-4 (ISBN)
    Konferens
    IEEE 21st International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS), 14-16 August 2013, San Francisco, CA, USA
    Tillgänglig från: 2014-03-15 Skapad: 2014-03-15 Senast uppdaterad: 2018-02-06Bibliografiskt granskad
    2. Bandwidth-aware Prefetching for Proactive Multi-video Preloading and Improved HAS Performance
    Öppna denna publikation i ny flik eller fönster >>Bandwidth-aware Prefetching for Proactive Multi-video Preloading and Improved HAS Performance
    Visa övriga...
    2015 (Engelska)Ingår i: Proceedings of the ACM International Conference on Multimedia (ACM Multimedia), New York, USA: Association for Computing Machinery (ACM), 2015, s. 551-560Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper considers the problem of providing users playing one streaming video the option of instantaneous and seamless playback of alternative videos. Recommendation systems can easily provide a list of alternative videos, but there is little research on how to best eliminate the startup time for these alternative videos. The problem is motivated by services that want to retain increasingly impatient users, who frequently watch the beginning of multiple videos, before viewing a video to the end. We present the design, implementation, and evaluation of an HTTP-based Adaptive Streaming (HAS) solution that provides careful prefetching and buffer management. We also present the design and evaluation of three fundamental policy classes that provide different tradeoffs between how aggressively new alternative videos are prefetched versus the importance of ensuring high playback quality. We show that our solution allows us to reduce the startup times of alternative videos by an order of magnitude and effectively adapt the quality such as to ensure the highest possible playback quality of the video being viewed. By improving the channel utilization we also address the discrimination problem that HAS clients often suffer from, allowing us to in some cases simultaneously improve the playback quality of the video being viewed and provide the value-added service of allowing instantaneous playback of the prefetched alternative videos.

    Ort, förlag, år, upplaga, sidor
    New York, USA: Association for Computing Machinery (ACM), 2015
    Nyckelord
    HTTP-based adaptive streaming (HAS); Bandwidth-aware prefetching; Multi-video preloading; Seamless playback
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-128168 (URN)10.1145/2733373.2806270 (DOI)000387861300064 ()978-1-4503-3459-4 (ISBN)
    Konferens
    ACM Multimedia 2015
    Tillgänglig från: 2016-05-20 Skapad: 2016-05-19 Senast uppdaterad: 2018-02-06
    3. BUFFEST: Predicting Buffer Conditions and Real-time Requirements of HTTP(S) Adaptive Streaming Clients
    Öppna denna publikation i ny flik eller fönster >>BUFFEST: Predicting Buffer Conditions and Real-time Requirements of HTTP(S) Adaptive Streaming Clients
    2017 (Engelska)Ingår i: MMSys’17, Proceedings of the 8th ACM on Multimedia Systems Conference, ACM , 2017, s. 76-87Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Stalls during video playback are perhaps the most important indicator of a client's viewing experience. To provide the best possible service, a proactive network operator may therefore want to know the buffer conditions of streaming clients and use this information to help avoid stalls due to empty buffers. However, estimation of clients' buffer conditions is complicated by most streaming services being rate-adaptive, and many of them also encrypted. Rate adaptation reduces the correlation between network throughput and client buffer conditions. Usage of HTTPS prevents operators from observing information related to video chunk requests, such as indications of rate adaptation or other HTTP-level information.; AB@This paper presents BUFFEST, a novel classification framework that can be used to classify and predict streaming clients' buffer conditions from both HTTP and HTTPS traffic. To illustrate the tradeoffs between prediction accuracy and the available information used by classifiers, we design and evaluate classifiers of different complexity. At the core of BUFFEST is an event-based buffer emulator module for detailed analysis of clients' buffer levels throughout a streaming session, as well as for automated training and evaluation of online packet-level classifiers. We then present example results using simple threshold-based classifiers and machine learning classifiers that only use TCP/IP packet-level information. Our results are encouraging and show that BUFFEST can distinguish streaming clients with low buffer conditions from clients with significant buffer margin during a session even when HTTPS is used.

    Ort, förlag, år, upplaga, sidor
    ACM, 2017
    Nyckelord
    Buffer condition estimation, HTTP-based adaptive streaming, HTTPS, Real-time requirements
    Nationell ämneskategori
    Data- och informationsvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-140913 (URN)10.1145/3083187.3083193 (DOI)978-1-4503-5002-0 (ISBN)
    Konferens
    8th ACM Conference on Multimedia Systems, June 20-23, 2017, Taipei, Taiwan
    Tillgänglig från: 2017-09-15 Skapad: 2017-09-15 Senast uppdaterad: 2018-02-06
    4. Empowering the creative user: personalized HTTP-based adaptive streaming of multi-path nonlinear video
    Öppna denna publikation i ny flik eller fönster >>Empowering the creative user: personalized HTTP-based adaptive streaming of multi-path nonlinear video
    Visa övriga...
    2013 (Engelska)Ingår i: FhMN '13 Proceedings of the 2013 ACM SIGCOMM workshop on Future human-centric multimedia networking, New York, USA: Association for Computing Machinery (ACM), 2013, s. 53-58Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper presents the design, implementation, and validation of a novel system that supports streaming and playout of personalized, multi-path, nonlinear video. In contrast to regular video, in which the file content is played sequentially, our design allows multiple nonlinear video sequences of the underlying (linear) video to be stitched together and played in any personalized order, and clients can be provided multiple path choices. The design combines the ideas of HTTP-based adaptive streaming (HAS) and multi-path nonlinear video. Personalization of the content is achieved with the use of a customized metafile, which is downloaded separately from the underlying media and the manifest file that defines the HAS structure. An extension to the user interface allows path choices to be presented to and made by the user. Novel buffer management and prefetching policies are used to ensure seamless uninterrupted playback regardless of client path choices, even under scenarios in which clients defer their choices until the last possible moment. Our solution allows creative home users to easily create their own multi-path nonlinear video, opening the door to an endless possibility of new opportunities and media forms.

    Ort, förlag, år, upplaga, sidor
    New York, USA: Association for Computing Machinery (ACM), 2013
    Nyckelord
    HTTP-based adaptive streaming, Multi-path video, Nonlinear video, Seamless playback
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:liu:diva-96695 (URN)10.1145/2491172.2491183 (DOI)978-1-4503-2183-9 (ISBN)
    Konferens
    ACM SIGCOMM 2013, Hong Kong, China, 12-16 August 2013
    Anmärkning

    Nominated as the Best Paper in the 2013 ACM SIGCOMM workshop on Future human-centric Multimedia Networking (FhMN)

    Tillgänglig från: 2013-08-23 Skapad: 2013-08-23 Senast uppdaterad: 2018-02-06Bibliografiskt granskad
    5. Quality-adaptive prefetching for interactive branched video using HTTP-based Adaptive Streaming
    Öppna denna publikation i ny flik eller fönster >>Quality-adaptive prefetching for interactive branched video using HTTP-based Adaptive Streaming
    Visa övriga...
    2014 (Engelska)Ingår i: MM 2014 - Proceedings of the 2014 ACM Conference on Multimedia, Association for Computing Machinery, Inc , 2014, s. 317-326Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Interactive branched video that allows users to select their own paths through the video, provides creative content designers with great personalization opportunities; however, such video also introduces significant new challenges for the system developer. For example, without careful prefetching and buffer management, the use of multiple alternative playback paths can easily result in playback interruptions. In this paper, we present a full implementation of an interactive branched video player using HTTP-based Adaptive Streaming (HAS) that provides seamless playback even when the users defer their branch path choices to the last possible moment. Our design includes optimized prefetching policies that we derive under a simple optimization framework, effective buffer management of prefetched data, and the use of parallel TCP connections to achieve efficient buffer workahead. Through performance evaluation under a wide range of scenarios, we show that our optimized policies can effectively prefetch data of carefully selected qualities along multiple alternative paths such as to ensure seamless playback, offering users a pleasant viewing experience without playback interruptions.

    Ort, förlag, år, upplaga, sidor
    Association for Computing Machinery, Inc, 2014
    Serie
    MM 2014 - Proceedings of the 2014 ACM Conference on Multimedia
    Nyckelord
    Branched video; HTTP-based Adaptive Streaming (HAS); Multipath/nonlinear streaming; Seamless playback
    Nationell ämneskategori
    Data- och informationsvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-116449 (URN)10.1145/2647868.2654951 (DOI)2-s2.0-84913597570 (Scopus ID)9781450330633 (ISBN)
    Konferens
    2014 ACM Conference on Multimedia, MM 2014
    Tillgänglig från: 2015-03-27 Skapad: 2015-03-26 Senast uppdaterad: 2018-02-06
    6. Optimized Adaptive Streaming of Multi-video Stream Bundles
    Öppna denna publikation i ny flik eller fönster >>Optimized Adaptive Streaming of Multi-video Stream Bundles
    2017 (Engelska)Ingår i: IEEE transactions on multimedia, ISSN 1520-9210, E-ISSN 1941-0077, Vol. 19, nr 7, s. 1637-1653Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In contrast to traditional video, multi-view video streaming allows viewers to interactively switch among multiple perspectives provided by different cameras. One approach to achieve such a service is to encode the video from all of the cameras into a single stream, but this has the disadvantage that only a portion of the received video data will be used, namely that required for the selected view at each point in time. In this paper, we introduce the concept of a multi-video stream bundle that consists of multiple parallel video streams that are synchronized in time, each providing the video from a different camera capturing the same event or movie. For delivery we leverage the adaptive features and time-based chunking of HTTP-based adaptive streaming, but now employing adaptation in both content and rate. Users are able to change their viewpoint on-demand and the client player adapts the rate at which data are retrieved from each stream based on the users current view, the probabilities of switching to other views, and the users current bandwidth conditions. A crucial component of such a system is the prefetching policy. For this we present an optimization model as well as a simpler heuristic that can balance the playback quality and the probability of playback interruptions. After analytically and numerically characterizing the optimal solution, we present a prototype implementation and sample results. Our prefetching and buffer management solution is shown to provide close to seamless playback switching when there is sufficient bandwidth to prefetch the parallel streams.

    Ort, förlag, år, upplaga, sidor
    IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2017
    Nyckelord
    HTTP-based adaptive streaming (HAS); multi-view video streaming; multi-video stream bundles; optimized prefetching; seamless stream switching
    Nationell ämneskategori
    Telekommunikation
    Identifikatorer
    urn:nbn:se:liu:diva-139270 (URN)10.1109/TMM.2017.2673412 (DOI)000404061800019 ()
    Anmärkning

    Funding Agencies|Swedish Research Council (VR); Center for Industrial Information Technology (CENIIT); Natural Sciences and Engineering Research Council of Canada

    Tillgänglig från: 2017-07-07 Skapad: 2017-07-07 Senast uppdaterad: 2018-02-06
  • 215.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Bergström, Patrik
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Eager, Derek
    University of Saskatchewan, Canada.
    Mahanti, Anirban
    NICTA, Australia.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Empowering the Creative User: Personalized HTTP-based Adaptive Streaming of Multi-path Nonlinear Video2013Ingår i: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 43, nr 4, s. 591-596Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the design, implementation, and validation of a novel system that supports streaming and playout of personalized, multi-path, nonlinear video. In contrast to regular video, in which the file content is played sequentially, our design allows multiple nonlinear video sequences of the underlying (linear) video to be stitched together and played in any personalized order, and clients can be provided multiple path choices. The design combines the ideas of HTTP-based adaptive streaming (HAS) and multi-path nonlinear video. Personalization of the content is achieved with the use of a customized metafile, which is downloaded separately from the underlying media and the manifest file that defines the HAS structure. An extension to the user interface allows path choices to be presented to and made by the user. Novel buffer management and prefetching policies are used to ensure seamless uninterrupted playback regardless of client path choices, even under scenarios in which clients defer their choices until the last possible moment. Our solution allows creative home users to easily create their own multi-path nonlinear video, opening the door to an endless possibility of new opportunities and media forms.

  • 216.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Bergström, Patrik
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Eager, Derek
    University of Saskatchewan.
    Mahanti, Anirban
    NICTA, Sydney, Australia.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Empowering the creative user: personalized HTTP-based adaptive streaming of multi-path nonlinear video2013Ingår i: FhMN '13 Proceedings of the 2013 ACM SIGCOMM workshop on Future human-centric multimedia networking, New York, USA: Association for Computing Machinery (ACM), 2013, s. 53-58Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the design, implementation, and validation of a novel system that supports streaming and playout of personalized, multi-path, nonlinear video. In contrast to regular video, in which the file content is played sequentially, our design allows multiple nonlinear video sequences of the underlying (linear) video to be stitched together and played in any personalized order, and clients can be provided multiple path choices. The design combines the ideas of HTTP-based adaptive streaming (HAS) and multi-path nonlinear video. Personalization of the content is achieved with the use of a customized metafile, which is downloaded separately from the underlying media and the manifest file that defines the HAS structure. An extension to the user interface allows path choices to be presented to and made by the user. Novel buffer management and prefetching policies are used to ensure seamless uninterrupted playback regardless of client path choices, even under scenarios in which clients defer their choices until the last possible moment. Our solution allows creative home users to easily create their own multi-path nonlinear video, opening the door to an endless possibility of new opportunities and media forms.

  • 217.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Eager, D.
    University of of Saskatchewan, Canada.
    Mahanti, A.
    NICTA, Australia.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Quality-adaptive prefetching for interactive branched video using HTTP-based Adaptive Streaming2014Ingår i: MM 2014 - Proceedings of the 2014 ACM Conference on Multimedia, Association for Computing Machinery, Inc , 2014, s. 317-326Konferensbidrag (Refereegranskat)
    Abstract [en]

    Interactive branched video that allows users to select their own paths through the video, provides creative content designers with great personalization opportunities; however, such video also introduces significant new challenges for the system developer. For example, without careful prefetching and buffer management, the use of multiple alternative playback paths can easily result in playback interruptions. In this paper, we present a full implementation of an interactive branched video player using HTTP-based Adaptive Streaming (HAS) that provides seamless playback even when the users defer their branch path choices to the last possible moment. Our design includes optimized prefetching policies that we derive under a simple optimization framework, effective buffer management of prefetched data, and the use of parallel TCP connections to achieve efficient buffer workahead. Through performance evaluation under a wide range of scenarios, we show that our optimized policies can effectively prefetch data of carefully selected qualities along multiple alternative paths such as to ensure seamless playback, offering users a pleasant viewing experience without playback interruptions.

  • 218.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Eager, Derek
    University of Saskatchewan, Canada.
    Mahanti, Anirban
    NICTA, Australia.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Bandwidth-aware Prefetching for Proactive Multi-video Preloading and Improved HAS Performance2015Ingår i: Proceedings of the ACM International Conference on Multimedia (ACM Multimedia), New York, USA: Association for Computing Machinery (ACM), 2015, s. 551-560Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper considers the problem of providing users playing one streaming video the option of instantaneous and seamless playback of alternative videos. Recommendation systems can easily provide a list of alternative videos, but there is little research on how to best eliminate the startup time for these alternative videos. The problem is motivated by services that want to retain increasingly impatient users, who frequently watch the beginning of multiple videos, before viewing a video to the end. We present the design, implementation, and evaluation of an HTTP-based Adaptive Streaming (HAS) solution that provides careful prefetching and buffer management. We also present the design and evaluation of three fundamental policy classes that provide different tradeoffs between how aggressively new alternative videos are prefetched versus the importance of ensuring high playback quality. We show that our solution allows us to reduce the startup times of alternative videos by an order of magnitude and effectively adapt the quality such as to ensure the highest possible playback quality of the video being viewed. By improving the channel utilization we also address the discrimination problem that HAS clients often suffer from, allowing us to in some cases simultaneously improve the playback quality of the video being viewed and provide the value-added service of allowing instantaneous playback of the prefetched alternative videos.

  • 219.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Eager, Derek
    University of Saskatchewan, Canada.
    Mahanti, Anirban
    NICTA, Australia.
    Shahmehri, Nahid
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Helping Hand or Hidden Hurdle: Proxy-assisted HTTP-based Adaptive Streaming Performance2013Ingår i: Modeling, Analysis & Simulation of Computer and Telecommunication Systems (MASCOTS), 2013 IEEE 21st International Symposium, IEEE , 2013, s. 182-191Konferensbidrag (Refereegranskat)
    Abstract [en]

    HTTP-based Adaptive Streaming (HAS) has become a widely-used video delivery technology. Use of HTTP enables relatively easy firewall/NAT traversal and content caching. While caching is an important aspect of HAS, there is not much public research on the performance impact proxies and their policies have on HAS. In this paper we build an experimental framework using open source Squid proxies and the most recent Open Source Media Framework (OSMF). A range of content-aware policies can be implemented in the proxies and tested, while the player software can be instrumented to measure performance as seen at the client. Using this framework, the paper makes three main contributions. First, we present a scenario-based performance evaluation of the latest version of the OSMF player. Second, we quantify the benefits using different proxy-assisted solutions, including basic best effort policies and more advanced content quality aware prefetching policies. Finally, we present and evaluate a cooperative framework in which clients and proxies share information to improve performance. In general, the bottleneck location and network conditions play central roles in which policy choices are most advantageous, as they significantly impact the relative performance differences between policy classes. We conclude that careful design and policy selection is important when trying to enhance HAS performance using proxy assistance.

  • 220.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Halepovic, Emir
    AT&T Labs, USA.
    Petajan, Eric
    AT&T Labs, USA.
    BUFFEST: Predicting Buffer Conditions and Real-time Requirements of HTTP(S) Adaptive Streaming Clients2017Ingår i: MMSys’17, Proceedings of the 8th ACM on Multimedia Systems Conference, ACM , 2017, s. 76-87Konferensbidrag (Refereegranskat)
    Abstract [en]

    Stalls during video playback are perhaps the most important indicator of a client's viewing experience. To provide the best possible service, a proactive network operator may therefore want to know the buffer conditions of streaming clients and use this information to help avoid stalls due to empty buffers. However, estimation of clients' buffer conditions is complicated by most streaming services being rate-adaptive, and many of them also encrypted. Rate adaptation reduces the correlation between network throughput and client buffer conditions. Usage of HTTPS prevents operators from observing information related to video chunk requests, such as indications of rate adaptation or other HTTP-level information.; AB@This paper presents BUFFEST, a novel classification framework that can be used to classify and predict streaming clients' buffer conditions from both HTTP and HTTPS traffic. To illustrate the tradeoffs between prediction accuracy and the available information used by classifiers, we design and evaluate classifiers of different complexity. At the core of BUFFEST is an event-based buffer emulator module for detailed analysis of clients' buffer levels throughout a streaming session, as well as for automated training and evaluation of online packet-level classifiers. We then present example results using simple threshold-based classifiers and machine learning classifiers that only use TCP/IP packet-level information. Our results are encouraging and show that BUFFEST can distinguish streaming clients with low buffer conditions from clients with significant buffer margin during a session even when HTTPS is used.

  • 221.
    Krishnamoorthi, Vengatanathan
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Carlsson, Niklas
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Halepovic, Emir
    ATandT Labs Res, NJ USA.
    Slow but Steady: Cap-based Client-Network Interaction for Improved Streaming Experience2018Ingår i: 2018 IEEE/ACM 26TH INTERNATIONAL SYMPOSIUM ON QUALITY OF SERVICE (IWQOS), IEEE , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to widespread popularity of streaming services, many streaming clients typically compete over bottleneck links for their own bandwidth share. However, in such environments, the rate adaptation algorithms used by modern streaming clients often result in instability and unfairness, which negatively affects the playback experience. In addition, mobile clients often waste bandwidth by trying to stream excessively high video bitrates. We present and evaluate a cap-based framework in which the network and clients cooperate to improve the overall Quality of Experience (QoE). First, to motivate the framework, we conduct a comprehensive study using the lab setup showing that a fixed rate cap comes with both benefits (e.g., data savings, improved stability and fairness) and drawbacks (e.g., higher startup times and slower recovery after stalls). To address the drawbacks while keeping the benefits, we then introduce and evaluate a framework that includes (i) buffer-aware rate caps in which the network temporarily boosts the rate cap of clients during video startup and under low buffer conditions, and (ii) boost-aware client-side adaptation algorithms that optimize the bitrate selection during the boost periods. Combined with information sharing between the network and clients, these mechanisms are shown to improve QoE, while reducing wasted bandwidth.

  • 222.
    Kumar, Pardeep
    et al.
    University of Oxford, England.
    Braeken, An
    Vrije University of Brussel, Belgium.
    Gurtov, Andrei
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten. ITMO University, Russia.
    Iinatti, Jari
    University of Oulu, Finland.
    Hoai Ha, Phuong
    University of Tromso, Norway.
    Anonymous Secure Framework in Connected Smart Home Environments2017Ingår i: IEEE Transactions on Information Forensics and Security, ISSN 1556-6013, E-ISSN 1556-6021, Vol. 12, nr 4, s. 968-979Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The smart home is an environment, where heterogeneous electronic devices and appliances are networked together to provide smart services in a ubiquitous manner to the individuals. As the homes become smarter, more complex, and technology dependent, the need for an adequate security mechanism with minimum individuals intervention is growing. The recent serious security attacks have shown how the Internet-enabled smart homes can be turned into very dangerous spots for various ill intentions, and thus lead the privacy concerns for the individuals. For instance, an eavesdropper is able to derive the identity of a particular device/appliance via public channels that can be used to infer in the life pattern of an individual within the home area network. This paper proposes an anonymous secure framework (ASF) in connected smart home environments, using solely lightweight operations. The proposed framework in this paper provides efficient authentication and key agreement, and enables devices (identity and data) anonymity and unlinkability. One-time session key progression regularly renews the session key for the smart devices and dilutes the risk of using a compromised session key in the ASF. It is demonstrated that computation complexity of the proposed framework is low as compared with the existing schemes, while security has been significantly improved.

  • 223.
    Kumar, Pardeep
    et al.
    UiT Arctic University of Norway, Norway.
    Gurtov, Andrei
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten. ITMO University, Russia.
    Iinatti, Jari
    University of Oulu, Finland.
    Sain, Mangal
    Dongseo University, South Korea.
    Ha, Phuong H.
    UiT Arctic University of Norway, Norway.
    Access Control Protocol With Node Privacy in Wireless Sensor Networks2016Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 16, nr 22, s. 8142-8150Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For preventing malicious nodes joining wireless sensor networks (WSNs), an access control mechanism is necessary for the trustworthy cooperation between the nodes. In addition to access control, recently, privacy has been an important topic regarding how to achieve privacy without disclosing the real identity of communicating entities in the WSNs. Based on elliptic curve cryptography, in this paper, we present an access control protocol with node privacy (called ACP) for the WSN. The proposed scheme not only accomplishes the node authentication but also provides the identity privacy (i.e., source to destination and vice-versa) for the communicating entities. Compared with the current state of the art, the proposed solution can defend actively against attacks. The efficacy and the efficiency of the proposed ACP are confirmed through the test bed analysis and performance evaluations.

  • 224.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    A framework for session-based ontology alignment2011Ingår i: Proceedings of the 6th International Workshop on Ontology Matching, CEUR Workshop Proceedings , 2011, s. 238-239Konferensbidrag (Refereegranskat)
    Abstract [en]

    [No abstract available]

  • 225.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Advances in Secure and Networked Information Systems – The ADIT Perspective: Festschrift in honor of professor NAHID SHAHMEHRI2012Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
    Abstract [en]

    This book contains contributions by current and former colleagues and PhD students of professor Nahid Shahmehri in celebration of her 60th birthday. Although it would be difficult to cover the full range of her academic contributions, we have at least been able to hint the importance and the breadth of her work. We have chosen the title ‘Advances in Secure and Networked Information Systems - The ADIT Perspective’ as many of the contributions of Nahid and her group have been in these areas, given a fairly broad interpretation of “networked information systems”. In this collection we have gathered both republications of past work as well as newly written articles.

     

  • 226.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Extending Standard Description Logics1994Ingår i: Proceedings of the International Workshop on Description Logics, 1994, s. 42-44Konferensbidrag (Refereegranskat)
  • 227.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Introduction to Description Logics2001Ingår i: Ontologies and Search - Proceedings of the 2nd OntoQuery Workshop, 2001, s. 53-56Konferensbidrag (Refereegranskat)
  • 228.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Filosofiska fakulteten.
    Ontologies in Bioinformatics and Systems Biology2004Ingår i: Artificial Intelligence Methods and Tools for Systems Biology / [ed] Werner Dubitzky and Francisco Azuaje, Springer Science+Business Media B.V., 2004, 5, s. 129-145Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Ontologies are being used in bioinformatics and systems biology, among others, for communication between people and organizations, as the basis for interoperability between systems, and as query models and indexes to repositories of information. In this chapter we give a background of the area and provide a state of the art overview. We present different possible definitions of ontology, examples of bio-ontologies and their use, formalisms that can be used to represent ontologies as well as tools that support the different stages in the life cycle of an ontology.

  • 229.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Part-Whole Reasoning in an Object-Centered Framework2000Bok (Refereegranskat)
    Abstract [en]

    In this book, the author develops an object-centered framework with specialized support of the part-of relation based on description logics. These logics are a family of object-centered knowledge representation languages tailored for describing knowledge about concepts and is-a hierarchies of these concepts. In addition to the representation and reasoning facilities provided by description logics for is-a, representation and reasoning facilities are introduced for part-of. Finally, the feasibility and the usefulness of the approach is demonstrated by applying the framework to various areas including domain modeling, agent-oriented scenarios, document management and retrieval, and composite concept learning.

  • 230.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Semantic Web, Ontologies and Linked Data2014Ingår i: Comprehensive Biomedical Physics: Volume 6: Bioinformatics / [ed] Brahme (ed in chief), Persson, (ed), Amsterdam: Elsevier, 2014, s. 67-76Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Researchers in various areas in the life sciences use biomedical data sources and tools for their research. However, with the explosion of the amountof available data sources and tools, researchers also face the difficulties of finding and retrieving relevant information and tools as well as integratinginformation from different sources. The vision of the Semantic Web alleviates these difficulties. In this chapter, we introduce the Semantic Web anddiscuss steps that have been taken toward this vision. We discuss ontologies as a key technology as well as the recent development of Linked Data. Further, for each of these, we list issues for future research.

  • 231.
    Lambrix, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Towards a semantic web for bioinformatics using ontology-based annotation2005Ingår i: 14th IEEE International Workshops on Enabling Technologies: Infrastructures for Collaborative Enterprises,2005, Institute of Electrical and Electronics Engineers (IEEE), 2005, s. 3-7Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nowadays, biologists use biological data sources and tools to find relevant information for their research. However, with the explosion of the amount of online accessible data and tools, finding the relevant sources and retrieving the relevant information is not an easy task. Further, often information from different sources needs to be integrated. The vision of a Semantic Web alleviates these difficulties. The Semantic Web is an extension of the current Web in which information is given a well-defined meaning by annotating Web content with ontology terms. In this paper we discuss the Semantic Web vision and focus on an important technology, ontologies, that is needed to make this vision happen.

  • 232.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Armiento, Rickard
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Delin, Anna
    School of Science and Engineering (SCI) at the Royal Institute of Technology, KTH, Sweden.
    Li, Huanyu
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Big Semantic Data Processing in the Materials Design Domain2018Ingår i: Encyclopedia of Big Data Technologies / [ed] Sherif Sakr and Albert Zomaya, Cham: Springer, 2018Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    To speed up the progress in the field of materials design, a number of challenges related to big data need to be addressed. This entry discusses these challenges and shows the semantic technologies that alleviate the problems related to variety, variability, and veracity.

  • 233.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Borgida, AlexRutgers University, NJ, USA.Lenzerini, MaurizioUniversita degli Studi di Roma "La Sapienza", Italy..Möller, RalfUniversity of Hamburg, Germany.Patel-Schneider, PeterBell Labs Research, NJ, USA.
    Proceedings of the 1999 International Workshop on Description Logics1999Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    The International Workshop on Description Logics was held in Linköping Sweden from July to August. It was an a affiliate event with the Sixteenth International Joint Conference on Articial Intelligence IJCAI Stockholm July 31 - August 6 and with the Sixth International Workshop on Knowledge Representation meets Databases KRDB Linköoping July 29-30.

    The workshop was organized in sessions on theoretical advances in de scription logics (2 sessions), applications of description logics (2 sessions), description logic systems (2 sessions) and extensions of description logics (1 session). Further there was a joint session with the Sixth International Workshop on Knowledge Representation Meets Databases. There were two invited talks Natasha Alechina gave a tutorial on logics for semi-structured data Robert MacGregor and Deborah McGuinness gave a presentation on DARPAs High Performance Knowledge Base project.

    The workshop was sponsored by the Swedish Research Council for Engineering Sciences TFR Telefonaktiebolaget LM Ericssons Stiftelse for främjande av elektroteknisk forskning, Linköpings kommun, Erda AB andthe Laboratory for Intelligent Information Systems, Linköpings universitet.Thanks go also to Lotta Nissen Yelena Turetskaya and a number of studentsfor their contribution to the organization.

  • 234.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Dragisic, Zlatan
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ivanova, Valentina
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Get my pizza right: Repairing missing is-a relations in ALC ontologies2012Ingår i: Second Joint International Semantic Technology Conference, Springer Berlin/Heidelberg, 2012, s. 17-32Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the increased use of ontologies in semantically-enabled applications, the issue of debugging defects in ontologies has become increasingly important. These defects can lead to wrong or incomplete results for the applications. Debugging consists of the phases of detection and repairing. In this paper we focus on the repairing phase of a particular kind of defects, i.e. the missing relations in the is-a hierarchy. Previous work has dealt with the case of taxonomies. In this work we extend the scope to deal with ALC ontologies that can be represented using acyclic terminologies. We present algorithms and discuss a system.

  • 235.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Dragisic, Zlatan
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ivanova, Valentina
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Anslow, Craig
    Middlesex University, London, UK.
    Visualization for Ontology Evolution2016Ingår i: VOILA 2016 Visualization and Interaction for Ontologies and Linked Data: Proceedings of the 2nd  International Workshop on Visualization and Interaction for Ontologies and Linked Data / [ed] Valentina Ivanova; Patrick Lambrix; Steffen Lohmann; Catia Pesquita, Rheinisch-Westfaelische Technische Hochschule Aachen University , 2016, s. 54-67Konferensbidrag (Refereegranskat)
    Abstract [en]

    One of the challenges for the ontology engineering community is theuser involvement in the engineering process. Ontologies are not static entities andthere is a demand for tools to support the user during the ontology evolution pro-cess. This paper aims to provide a set of functionality requirements for ontologyevolution systems, with a particular focus on the visualization of the ontologies,their versions and information needed for ontology evolution tasks. Further, wereview the current state of the art in ontology evolution systems with respect tothe requirements and the visualization. We also view ontologies as software anddiscuss approaches from the software visualization area that could be used forontology evolution visualization.

  • 236.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Edberg, Anna
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Evaluation of ontology merging tools2003Ingår i: Pacific Symposium on Biocomputing, World Scientific , 2003, s. 589-600Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ontologies are being used nowadays in many areas, including bioinformatics. One of the issues in ontology research is the aligning and merging of ontologies. Tools have been developed for ontology merging, but they have not been evaluated for their use in bioinformatics. In this paper we evaluate two of the most well-known ontology merging tools with a bioinformatics perspective. As test ontologies we have used Gene Ontology and Signal-Ontology.

  • 237.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Edberg, Anna
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Manis, Carolyn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Tan, He
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Merging DAML+OIL bio-ontologies2003Ingår i: International workshop on description logics, 2003Konferensbidrag (Refereegranskat)
  • 238.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Göthe Lundgren, Maud
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska fakulteten.
    Kamkar, Mariam
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Computer science as an integrated part of engineering education1997Ingår i: Proceedings of the ACM SIGCSE/SIGCUE Conference on Integrating Technology into Computer Science Education, 1997, s. 151-Konferensbidrag (Refereegranskat)
  • 239.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Habbouche, Manal
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Perez, Marta
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Evaluation of ontology development tools for bioinformatics2003Ingår i: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 19, nr 12, s. 1564-1571Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ontologies are being used nowadays in many areas, including bioinformatics. To assist users in developing and maintaining ontologies a number of tools have been developed. In this paper we compare four such tools, Protégé-2000, Chimaera, DAG-Edit and OilEd. As test ontologies we have used ontologies from the Gene Ontology Consortium. No system is preferred in all situations, but each system has its own strengths and weaknesses.

  • 240.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Habbouche, Manal
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Perez, Marta
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Evaluation of ontology development tools for bioinformatics2005Ingår i: Yearbook of the International Medical Informatics Association 2005 / [ed] Haux R, Kulikowski C, Stuttgart: Schattauer Verlagsgesellschaft mbH , 2005, s. 547-554Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Ontologies are being used nowadays in many areas, including bioinformatics. To assist users in developing and maintaining ontologies a number of tools have been developed. In this paper we compare four such tools, Protégé-2000, Chimaera, DAG-Edit and OilEd. As test ontologies we have used ontologies from the Gene Ontology Consortium. No system is preferred in all situations, but each system has its own strengths and weaknesses.

  • 241.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Hyvönen, EeroAalto University, Finland.Blomqvist, EvaLinköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.Presutti, ValentinaSTLab ISTC-CNR, Italy.Qi, GuilinSoutheast University, China.Sattler, UliUniversity of Manchester, UK.Ding, YingIndiana University Bloomingtom, USA.Ghidini, ChiaraFondazione Bruno Kessler, Italy.
    Knowledge Engineering and Knowledge Management: EKAW 2014 Satellite Events, VISUAL, EKM1, and ARCOE-Logic, Linköping, Sweden, November 24-28, 2014. Revised Selected Papers2015Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    This volume contains the Satellite Events proceedings of the 19th International Conference on Knowledge Engineering and Knowledge Management (EKAW 2014), held in Linköping, Sweden, during November 24–28, 2014. This was the first EKAW conference in a Nordic country. It was concerned with all aspects of eliciting, acquiring, modeling, and managing knowledge, the construction of knowledge-intensive systems and services for the Semantic Web, knowledge management, e-business, natural language processing, intelligent information integration, personal digital assistance systems, and a variety of other related topics. The special focus of EKAW2014 was Diversity.

  • 242.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ivanova, Valentina
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    A unified approach for debugging is-a structure and mappings in networked taxonomies2013Ingår i: Journal of Biomedical Semantics, ISSN 2041-1480, E-ISSN 2041-1480, Vol. 4, artikel-id 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    With the increased use of ontologies and ontology mappings in semantically-enabled applications such as ontology-based search and data integration, the issue of detecting and repairing defects in ontologies and ontology mappings has become increasingly important. These defects can lead to wrong or incomplete results for the applications.

    Results

    We propose a unified framework for debugging the is-a structure of and mappings between taxonomies, the most used kind of ontologies. We present theory and algorithms as well as an implemented system RepOSE, that supports a domain expert in detecting and repairing missing and wrong is-a relations and mappings. We also discuss two experiments performed by domain experts: an experiment on the Anatomy ontologies from the Ontology Alignment Evaluation Initiative, and a debugging session for the Swedish National Food Agency.

    Conclusions

    Semantically-enabled applications need high quality ontologies and ontology mappings. One key aspect is the detection and removal of defects in the ontologies and ontology mappings. Our system RepOSE provides an environment that supports domain experts to deal with this issue. We have shown the usefulness of the approach in two experiments by detecting and repairing circa 200 and 30 defects, respectively.

  • 243.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ivanova, Valentina
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Dragisic, Zlatan
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Contributions of LiU/ADIT to Debugging Ontologies and Ontology Mappings2012Ingår i: Advances in secure and networked information systems: the ADIT perspective ; Festschrift in honor of professor Nahid Shahmehri / [ed] Patrick Lambrix, Linköping: Linköping University Electronic Press, 2012, s. 109-120Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    This book contains contributions by current and former colleagues and PhD students of professor Nahid Shahmehri in celebration of her 60th birthday. Although it would be difficult to cover the full range of her academic contributions, we have at least been able to hint the importance and the breadth of her work. We have chosen the title ‘Advances in Secure and Networked Information Systems - The ADIT Perspective’ as many of the contributions of Nahid and her group have been in these areas, given a fairly broad interpretation of “networked information systems”. In this collection we have gathered both republications of past work as well as newly written articles.

  • 244.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Kaliyaperumal, Rajaram
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    A Session-based Approach for Aligning Large Ontologies: Extended Semantic Web Conference2013Ingår i: The Semantic Web: Semantics and Big Data: 10th International Conference, ESWC 2013, Montpellier, France, May 26-30, 2013. Proceedings / [ed] Philipp Cimiano, Oscar Corcho, Valentina Presutti, Laura Hollink, Sebastian Rudolph, Springer Berlin/Heidelberg, 2013, s. 46-60Konferensbidrag (Refereegranskat)
    Abstract [en]

    There are a number of challenges that need to be addressed when aligning large ontologies. Previous work has pointed out scalability and efficiency of matching techniques, matching with background knowledge, support for matcher selection, combination and tuning, and user involvement as major requirements. In this paper we address these challenges. Our first contribution is an ontology alignment framework that enables solutions to each of the challenges. This is achieved by introducing different kinds of interruptable sessions. The framework allows partial computations for generating mapping suggestions, partial validations of mappings suggestions and use of validation decisions in (re)computation of mapping suggestions and the recommendation of alignment strategies to use. Further, we describe an implemented system providing solutions to each of the challenges and show through experiments the advantages of the session-based approach.

  • 245.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten. Swedish e-Science Research Centre, Linköping University, Linköping, Sweden.
    Kaliyaperumal, Rajaram
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    A session-based ontology alignment approach enabling user involvement2017Ingår i: Semantic Web, ISSN 1570-0844, E-ISSN 2210-4968, Vol. 8, nr 2, s. 225-251Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the current challenges in ontology alignment is the user involvement in the alignment process. To obtain high-quality alignments user involvement is needed for validation of matching results as well as in the mapping generation process. Further, there is a need for supporting the user in tasks such as matcher selection, combination and tuning.

    In this paper we introduce a conceptual ontology alignment framework that enables user involvement in a natural way. This is achieved by introducing different kinds of interruptible sessions. The framework allows partial computations for generating mapping suggestions, partial validations of mapping suggestions, recommendations for alignment strategies as well as the use of validation decisions in the (re-)computation of mapping suggestions and the recommendations. Further, we show the feasibility of the approach by implementing a session-based version of an existing system. We also show through experiments the advantages of our approach for ontology alignment as well as for evaluation of ontology alignment strategies.

  • 246.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Kaliyaperumal, Rajaram
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Contributions of LiU/ADIT to Ontology Alignment2012Ingår i: Advances in secure and networked information systems: the ADIT perspective ; Festschrift in honor of professor Nahid Shahmehri / [ed] Patrick Lambrix, Linköping: Linköping University Electronic Press, 2012, s. 97-108Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    This book contains contributions by current and former colleagues and PhD students of professor Nahid Shahmehri in celebration of her 60th birthday. Although it would be difficult to cover the full range of her academic contributions, we have at least been able to hint the importance and the breadth of her work. We have chosen the title ‘Advances in Secure and Networked Information Systems - The ADIT Perspective’ as many of the contributions of Nahid and her group have been in these areas, given a fairly broad interpretation of “networked information systems”. In this collection we have gathered both republications of past work as well as newly written articles.

  • 247.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Kamkar, Mariam
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Computer Science as an Integrated Part of Engineering Education1998Ingår i: Proceedings of the Third ACM SIGCSE/SIGCUE Conference on Integrating Technology into Computer Science Education, 1998, s. 153-156Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Information Technology curriculum at Linköping University has as goal to form engineers with an integrated view of engineering. The teaching philosophy in this curriculum is Problem-Based Learning. The education in each term is organised in a number of themes where topics from different disciplines are integrated. We describe a particular term in the Information Technology curriculum as an example of the approach and the integration of computer science teaching with the teaching of other disciplines. An important advantage of the approach is that the students discover interactions between different disciplines and view the different topics as naturally connected. Also, the students seem to have a better understanding of the topics and are better motivated. Further, they obtain improved communication and co-operation skills. Another advantage is that the approach is appreciated by our female students, which has led to a higher percentage of female students in this curriculum compared to our other computer science curricula.

  • 248.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Kemp, GrahamChalmers University of Technology.
    Proceedings of the Seventh International Conference on Data Integration in the Life Sciences2010Proceedings (redaktörskap) (Refereegranskat)
  • 249.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Larocchia, Pierpaolo
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik.
    Learning Composite Concepts1998Ingår i: Proceedings of the International Workshop on Description Logics, 1998, s. 147-152Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a framework to learn concepts from different kinds of observations. We define a language to describe meta-concepts, that represent the sets of possible concepts that can be the result of learning given a set of observations. The kinds of observations that we have studied are subsumption, membership and part-of. We exemplify the framework by showing how composite concepts can be learned in a specific description logic and we show that previous machine learning approaches in description logics can be reformulated in our framework. 1 Introduction In [LM96] the problem of learning composite concepts was formulated in the framework of description logics. Description logics are restricted variants of firstorder logic providing a form of logical bias that dates back to semantic networks. Some recent work investigates concept learning in the context of description logics

    Learning Composite Concepts.. Available from: http://www.researchgate.net/publication/220956947_Learning_Composite_Concepts [accessed Jul 1, 2015].

  • 250.
    Lambrix, Patrick
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    Liu, Qiang
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    A System for Debugging is-a Structure in Networked Taxonomies2011Ingår i: Demo proceeding of the 10th International Semantic Web Conference, 2011Konferensbidrag (Refereegranskat)
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