Doctoral Thesis
The amount of information on the Web is constantly increasing and also there is a wide variety of information available such as news, encyclopedia articles, statistics, survey data, stock information, events, bibliographies etc. The information is characterized by heterogeneity in aspects such as information type, modality, structure, granularity, quality and by its distributed nature. The two primary techniques by which users on the Web are looking for information are (1) using Web search engines and (2) browsing the links between information. The dominant mode of information presentation is mainly static in the form of text, images and graphics. Interactive visualizations offer a number of advantages for the presentation and exploration of heterogeneous information on the Web: (1) They provide different representations for different, very large and complex types of information and (2) large amounts of data can be explored interactively using their attributes and thus can support and expand the cognition process of the user. So far, interactive visualizations are still not an integral part in the search process of the Web. The technical standards and interaction paradigms to make interactive visualization usable by the mass are introduced only slowly through standardatization organizations. This work examines how interactive visualizations can be used for the linking and search process of heterogeneous information on the Web. Based on principles in the areas of information retrieval (IR), information visualization and information processing, a model is created, which extends the existing structural models of information visualization with two new processes: (1) linking of information in visualizations and (2) searching, browsing and filtering based on glyphs. The Vizgr toolkit implements the developed model in a web application. In four different application scenarios, aspects of the model will be instantiated and are evaluated in user tests or examined by examples.
In the last years the e-government concentrated on the administrative aspects of administrative modernisation. In the next step the e-discourses will gain in importance as an instrument of the public-friendliness and means of the e-democracy/e-participation. With growing acceptance of such e-discourses, these will fastly reach a complexity, which could not be mastered no more by the participants. Many impressions, which could be won from presence discussions, will be lacking now. Therefore the exposed thesis has the objective of the conception and the prototypical implementation of an instrument (discourse meter), by which the participants, in particular the moderators of the e-discourse, are capable to overlook the e-discourse at any time and by means of it, attain their discourse awareness. Discourse awareness of the present informs about the current action in the e-discourse and discourse awareness of the past about the past action, by which any trends become visible. The focus of the discourse awareness is located in the quantitative view of the action in the e-discourse. From the model of e-discourse, which is developed in this thesis, the questions of discourse awareness are resulting, whose concretion is the basis for the implementation of the discourse meter. The discourse sensors attached to the model of the e-discourse are recording the actions of the e-discourse, showing events of discourse, which are represented by the discourse meter in various forms of visualizations. The concept of discourse meter offers the possibility of discourse awareness relating to the present as monitoring and the discourse awareness relating to the past as query (quantitative analysis) to the moderators of the e-discourse.