Now showing 1 - 10 of 33
  • Publication
    User interfaces for pervasive games
    ( 2007)
    Röcker, C.
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    Magerkurth, C.
    ;
    Haar, M.
  • Publication
    Exploiting context information for identification of relevant experts in collaborative workplace-embedded e-learning environments
    ( 2007)
    Lokaiczyk, R.
    ;
    Godehardt, E.
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    Faatz, A.
    ;
    Goertz, M.
    ;
    Kienle, A.
    ;
    Wessner, M.
    ;
    Ulbrich, A.
    This work introduces an approach to discover collaboration partners and adequate advising experts in a workplace-embedded collaborative e-learning environment. Based on existing papers dealing with work task and user context modelling, we propose the following steps towards a successful collaboration initiation. In the beginning, the user's current process task needs to be identified (1). Taking into account the knowledge about the current process, availability of experts as well as organizational and social distance, relevant experts regarding the actual work task of the learner are pre-selected by the environment (2). Depending on the pre-selection and users' preferences, the potential collaboration partners are displayed in an expert list (3). That way, the learner is able to initiate beneficial collaborations, whose transcripts are used to enhance the existing knowledge base of learning documents (4).
  • Publication
    Third International Workshop on Pervasive Gaming Applications - PerGames 2006
    ( 2006)
    Magerkurth, C.
    ;
    Chalmers, M.
    ;
    Schäfer, L.
  • Publication
    Large margin methods for structured and interdependent output variables
    ( 2005)
    Tsochantaridis, I.
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    Joachims, T.
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    Hofmann, T.
    ;
    Altun, Y.
    Learning general functional dependencies between arbitrary input and output spaces is one of the key challenges in computational intelligence. While recent progress in machine learning has mainly focused on designing flexible and powerful input representations, this paper addresses the complementary issue of designing classification algorithms that can deal with more complex outputs, such as trees, sequences, or sets. More generally, we consider problems involving multiple dependent output variables, structured output spaces, and classification problems with class attributes. In order to accomplish this, we propose to appropriately generalize the well-known notion of a separation margin and derive a corresponding maximum-margin formulation. While this leads to a quadratic program with a potentially prohibitive, i.e. exponential, number of constraints, we present a cutting plane algorithm that solves the optimization problem in polynomial time for a large class of problems. The proposed method has important applications in areas such as computational biology, natural language processing, information retrieval/extraction, and optical character recognition. Experiments from various domains involving different types of output spaces emphasize the breadth and generality of our approach.
  • Publication
    Saying what it means: Semi-automated (news) media annotation
    ( 2004)
    Nack, F.
    ;
    Putz, W.
    This paper considers the automated and semi-automated annotation of audiovisual media in a new type of production framework, A4SM (Authoring System for Syntactic, Semantic and Semiotic Modelling). We present the architecture of the framework, describe a prototypical camera, a handheld device for basic semantic annotation, and an editing suite to demonstrate how video material can be annotated in real time and how this information can not only be used for retrieval but also can be used during the different phases of the production process itself. We then outline the underlying XML Schema based content description structures of A4SM and discuss the pros and cons of our approach of evolving semantic networks as the basis for audio-visual content description.
  • Publication
    JASMINE: A Java tool for multimedia collaboration on the internet
    ( 2003)
    Shirmohammadi, S.
    ;
    Saddik, A. el
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    Georganas, N.D.
    ;
    Steinmetz, R.
    Although collaboration tools have existed for a long time [8], Internet-based multimedia collaboration has recently received a lot of attention mainly due to easy accessibility of the Internet by ordinary users. The Java platform and programming language has also introduced yet another level of easy access: platform-independent computing. As a result, it is very attractive to use Java to design multimedia collaboration systems for the Internet. Today there are many systems, which use Java for multimedia collaboration. However, most of these systems require the shared Java application to be re-written according to the collaboration system's Application Programming Interface (API)-a task which is sometimes difficult or even impossible. In this paper, we describe a practical approach for transparent collaboration with Java. Our approach is transparent in that the Java application can be shared as is with no modifications. The main idea behind our system is that user events occurring through the interactions with the application can be caught, distributed, and reconstructed, hence allowing Java applications to be shared transparently. Our architecture allows us to make the huge installed base of Java applications collaborative, without any modification to their original code. We also prove the feasibility of our architecture by implementation of the JASMINE 1 prototype.
  • Publication
    Context-aware service based on secure mobile agents
    ( 2002)
    Pinsdorf, U.
    ;
    Peters, J.
    ;
    Hoffmann, M.
    ;
    Gupta, P.
    In this paper we introduce the concept of context-aware services as an extended form of locationbased services. We describe a new architecture for realizing context-aware services which has a number of key benefits. This architecture relays on mobile software agents as security-centric middleware. Our approach allows to combine disjunct databases by establishing applicationdependant links between remote data sets with a proprietary access. We describe all necessary roles and places to establish a multilateral security concept for all participants.
  • Publication
    XQuery by the book: The IPSI XQuery Demonstrator
    ( 2002)
    Fankhauser, P.
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    Groh, T.
    ;
    Overhage, S.
    The IPSI XQuery Demonstrator (IPSI-XQ) implements the XQuery surface syntax, its mapping to the XQuery Core Language, and the static and dynamic semantics of XQuery Core "by the book", following the formal specification as faithfully as possible. Its main purpose is to provide a framework for testing various language design options, and for experimenting with techniques to use type information for efficiently storing and querying XML.