Now showing 1 - 10 of 123
  • Publication
    Unsupervised duplicate detection using sample non-duplicates
    ( 2006)
    Lehti, P.
    ;
    Fankhauser, P.
    The problem of identifying objects in databases that refer to the same real world entity, is known, among others, as duplicate detection or record linkage. Objects may be duplicates, even though they are not identical due to errors and missing data. Typical current methods require deep understanding of the application domain or a good representative training set, which entails significant costs. In this paper we present an unsupervised, domain independent approach to duplicate detection that starts with a broad alignment of potential duplicates, and analyses the distribution of observed similarity values among these potential duplicates and among representative sample non-duplicates to improve the initial alignment. Additionally, the presented approach is not only able to align flat records, but makes also use of related objects, which may significantly increase the alignment accuracy. Evaluations show that our approach supersedes other unsupervised approaches and reaches almost the same accuracy as even fully supervised, domain dependent approaches.
  • Publication
    Ontologically-enriched unified user modeling for cross-system personalization
    ( 2005)
    Mehta, B.
    ;
    Niederée, C.
    ;
    Stewart, A.
    ;
    Degemmis, M.
    ;
    Lops, P.
    ;
    Semeraro, G.
    Personalization today has wide spread use on many Web sites. Systems and applications store preferences and information about users in order to provide personalized access. However, these systems store user profiles in proprietary formats. Although some of these systems store similar information about the user., exchange or reuse of information is not possible and information is duplicated. Additionally, since user profiles tend to be deeply buried inside such systems, users have little control over them. This paper proposes the use of a common ontology-based user context model as a basis for the exchange of user profiles between multiple systems and, thus, as a foundation for cross-system personalization.
  • Publication
    Flexible notifications and task models for cooperative work management
    ( 2005)
    Rubart, J.
    ;
    Richter, H.
    Knowledge intensive cooperative work requires emergent workflow management. Participants interact with the workflow engine and jointly redefine and activate workflow structure. To improve the usability of such systems we present reconfigurable notification mechanisms as well as shared task models that can be used from diverse clients at the same time focusing on different kinds of visualization and navigation.
  • Publication
    Small groups learning synchronously online at the workplace: The interaction of factors determining outcome and acceptance
    ( 2005)
    Münzer, S.
    ;
    Xiao, B.
    E-learning at the workplace might be accomplished by synchronous cooperative learning sessions of small groups using net-based communication. This form of learning is suitable both for course-based e-learning as well as for knowledge transfer within the company. The small groups learn self-regulated, i.e. without the guidance of an instructor. However, the learning tasks are pre-defined and a specific learning process is precisely described. In the present study, the goal of the cooperative learning sessions is to deepen pre-existing declarative knowledge. During cooperative learning, group members are required to actively use, acquire, enrich and exchange their knowledge. In a field study carried out in a large software company, a software tool was used which supported the specific process by phase-specific delivering of instructions and learning materials as well as by means of process control (including turn-taking, role assignment, and coordination of task flow). Th e results of the empirical evaluation demonstrate a high amount of topic-oriented contributions and the realization of the expected learning activities. However, feedback data indicated a low acceptance of the software tool because of its restrictive process control. It is discussed that there might have been a non-optimal interaction between the factors technology and target group in the study.
  • Publication
    Pervasive games: Bringing computer entertainment back to the real world
    ( 2005)
    Magerkurth, C.
    ;
    Cheok, A.D.
    ;
    Mandryk, R.L.
    ;
    Nilsen, T.
  • Publication
    Understanding and tailoring your scientific information environment: A context-oriented view on e-science support
    ( 2005)
    Niederée, C.
    ;
    Stewart, A.
    ;
    Muscogiuri, C.
    ;
    Hemmje, M.
    ;
    Risse, T.
  • Publication
    Agilo: A highly flexible groupware framework
    ( 2005)
    Guicking, A.
    ;
    Tandler, P.
    ;
    Avgeriou, P.
    Today there exist many frameworks for the development of synchronous groupware applications. Although the domain of these applications is very heterogeneous, existing frameworks provide only limited flexibility to integrate diverse groupware applications in a meaningful way. We identify five variation points that a groupware framework needs to offer in a flexible way in order to facilitate the integration of diverse groupware applications. Based on these variation points, we propose a groupware framework called Agilo that tries to overcome the limited flexibility of existing frameworks by offering multiple realizations of these variation points and providing a modular architecture to simplify the integration of applications and the extensibility and adaptability to different application and integration requirements.
  • Publication
    Modelling interactive, three-dimensional information visualizations
    ( 2005)
    Jäschke, G.
    ;
    Gupta, P.
    ;
    Hemmje, M.
    Research on information visualization has so far established an outline of the information visualization process and shed light on a broad range of detail aspects involved. However, there is no model in place that describes the nature of information visualization in a coherent, detailed, and well-defined way. We believe that the lack of such a lingua franca hinders communication on and application of information visualization techniques. Our approach is to design a declarative language for describing and defining information visualization techniques. The information visualization modelling language (IVML) provides a means to formally express, note, preserve, and communicate structure, appearance, behaviour, and functionality of information visualization techniques and applications in a standardized way. The anticipated benefits comprise both application and theory.
  • Publication
    Requirements for secure logging of decentralized cross-organizational workflow executions
    ( 2005)
    Wombacher, A.
    ;
    Wieringa, R.
    ;
    Jonker, W.
    ;
    Kneevi, P.
    ;
    Pokraev, S.
    The control of actions performed by parties involved in a decentralized cross-organizational workflow is done by several independent workflow engines. Due to the lack of a centralized coordination control, an auditing is required which supports a reliable and secure detection of malicious actions performed by these parties. In this paper we identify several issues which have to be resolved for such a secure logging system. Further, security requirements for a decentralized data store are investigated and evaluated with regard to decentralized data stores.