ADVANCED DATABASES AND METADATA
ERCIM News No.35 - October 1998

On-line Information Services for Trade Fairs and Congresses based on Multimedia Databases

by Thomas Klement, Thomas Risse, Matthias Hemmje, Martin Leissler and Matthias Malsy


Based on the fast development of high speed communication networks, the increasing convergence of multimedia standards and virtual reality (VR) standards establishes a growing need for technological integration in the domain of online multimedia information systems. The availability of such electronic publication- and information systems also leads to new requirements in the application context of trade fair and congress information systems. New forms of information acquisition and usage are enabled by means of interactive multimedia catalogue systems and interactive virtual-reality applications.

In cooperation with leading trade fair and congress organizers, the Integrated Publication and Information Systems Institute of GMD in Darmstadt is designing, specifying and testing an online multimedia catalogue system based on an object relational data base management system (DBMS). It enables the efficient and flexible acquisition, management and maintenance of online catalogue information for trade fairs and congresses. Among others, the main advantages of the chosen design are:

The online multimedia catalogue system is based on the so called Information Catalog Environment (ICE) components which were developed by research divisions of GMD Institute for Integrated Publication and Information Systems. The software components extend an object relational DBMS with advanced functionality for providing multidimensional catalogue support and structured management of dynamic text, multimedia and VR document collections. The database extensions are realized on the basis of the so-called Object Relational DataBlade technology of Informaix Dynamic Server. Both, the structuring and navigation support and the virtual reality visualization support within the ICE and the VRML (Virtual Reality Modeling Language) DataBlade Modules are described in this article.

Hierarchical and Multidimensional Categorization

The ICE-system represents and manages an arbitrary number of independent hierarchical tree structures, so called ICE-Dimensions. These are categorizing documents w.r.t. their content or application-oriented usage. According to the depth of the hierarchy, the documents are categorized at an increasing level of detail for each ICE dimension. A mapping function between documents and leaves of an ICE dimension¥s categorization hierarchy specifies a multidimensional, hierarchical coordinate in the overall ICE document-space. This so-called polyhierarchical classification enables an automatic (which means a DBMS-supported) search for documents in similar positions. These are documents which differ only in one leave or a definite amount of leaves.

Within the user interface, the ICE navigation menus are dynamically generated on each request of a document. This generation of navigation support menus is based on the polyhierarchical representation of the overall document space. In this way, inconsistent links are avoided because a document, once deleted from the document space, will not be generated as a navigatable part of an ICE navigation menu any more. By usage of ICE, an application developer will typically create a focus and context sensitive user interface for preparing an interactive browsing or search-oriented access to a document collection. The focus of the application¥s user interface will display documents of the current position in the document collection while the context area will display the navigation menus. This means, ICE navigation menus visualize the position of the documents within the ICE document space.

Features of the ICE DataBlade Module

The ICE DataBlade Module provides a set of Structured Query Language (SQL) data types and functions which simplifies and supports the handling of polyhirarchical ICE tables and structures. This includes the definition and use of document templates and patterns which define default documents for subpartitions of the overall document space. Furthermore, the ICE DataBlade Module consists of functions that automatically generate web based user interfaces menus supporting user navigation and information retrieval by query by exchange (QBE) forms.

Congress Online - an ICE application

The ICE approach is currently being applied in the Congress Online project. It designs a system for electronic congress information for a leading European congress organizer. Congress Online implements electronic support to distribute congress information, to register congresses, to submit and evaluate abstracts, and to support travel and hotel reservation. Additionally Congress Online supports innovative marketing oriented information services which are seamlessly integrated into the congress information services.

Integration aspects

The integration of the ICE DataBlade Module into the INFORMIX Web Integration Module allows the embedding of ICE-functions into documents. Further integration with a Text DataBlade Module enables the full text indexing of all documents within the ICE system. Furthermore, the ICE system can be combined with the INFORMIX Image DataBlade to support DBMS based image catalogue applications. Further integration with the VRML DataBlade has also been developed in GMD Institute for Integrated Publication and Information Systems. The functionality of this DataBlade will be described below.

Virtual Trade Fair - a VRML application

Within an online multimedia congress and trade fair catalogue, a virtual-reality overview of a trade fair hall can display information about all companies exhibiting their products on stalls in the hall. The possibility of walking through a three dimensional visualization of the trade fair hall, enables visitors to plan their routes through the trade fair more easily, long before the actual visit takes place. The benefits for exhibitors are, eg, that they get an impression of their stand and its position among competitor’s stalls. Furthermore, the visualization of the hall and stands could be used as a metaphor to access further information about the exhibitors and their products, or to send requests for meeting appointments to staff members of the exhibitors.

The description language VRML is widely used on the internet to describe three dimensional scenes. The VRML-DataBlade extends an object relational database with the ability to archive and work on VRML scenes. With the VRML data type, which is realized through the VRML DataBlade, is it possible to store scenes directly in the tables of the database. The VRML data type also introduces new functions to handle such VRML objects on the SQL level like any other data type (eg text or numbers). The functions allows the programmer, for example, to select several scenes from a table and summarize the result into a new VRML scene.

Further Demands for Information Visualization

Due to increasing amount of often complex structured data collections within global networks, appropriate visualization methods to support information retrieval (ie, browsing and search) tasks and data mining tasks for naive end users of information systems gain growing importance. The available graphics performance of network client systems is steadily growing, too. Therefore, methods for three-dimensional visualization can be applied more and more easily.

Supporting Dynamic VRML Scenes with the VRML DataBlade

A specific ability of the VRML DataBlade is to support information visualization by means of generating new VRML scenes from operational data through the dynamic embedding of data into VRML scenes. Therefore, it is possible to use the VRML DataBlade as a VRML library within the DBMS enabling the SQL-based development of information visualization applications. The VRML DataBlade supports information visualization by means of a so called Server Side Include mechanism. This means that special VRML nodes containing SQL database queries are included within regular VRML scenes.

These nodes can also contain templates that are used to generate new VRML nodes to visualize the query result. The database query is processed during a request upon the dynamic VRML scene. For each row of a result set, new VRML nodes are instantiated based on the specified template. Therefore, the generated scene is an information visualization of the respective database query. The resulting scene is then sent to the client as a static VRML representation. With this method, it is easy to generate, eg, the virtual-reality-based user interface of the trade fair information system, mentioned above, based on operational data from traditional relational business database applications.

Outlook

In addition to the ICE and VRML DataBlade, three other DataBlades are the object of research and development at GMD Institute for Integrated Publication and Information Systems. Soon, a first implementation of an MPEG (Motion Picture Expert Group) DataBlade will be finished, enabling a tight DBMS supported integration of media types like sound, images and video into the already existing catalog and virtual reality environments. Furthermore, the MPEG DataBlade can be applied for the DBMS-supported management and processing of digital video.

More information on the Web at: http://www.darmstadt.gmd.de/~klement/congressonline/congressonlinee.html

Please contact:

Matthias Hemmje - GMD
Tel: +49 6151 869 844
E-mail: matthias.hemmje@gmd.de

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