ERCIM News No.25 - April 1996 - GMD

ZENO - A Group Decision Support System for the World Wide Web

by Thomas F. Gordon, Nikos Karacapilidis and Hans Voss

ZENO is a mediating system based on the World Wide Web. Building on decision theory and a formal model of argumentation, ZENO offers intelligent assistance to human mediators, facilitators, arbitrators and other "trusted third parties" by providing an issue-based discussion forum or conferencing system.

ZENO allows an arbitrary large number of interested parties in various locations to take part in a discussion and decision making process that may extend over a long period of time. Using the graphical ZENO interface over the World Wide Web, even inexperienced users can easily view the structure of all arguments presented so far, retrieve messages submitted by other parties and contribute messages presenting their issues, arguments and positions. These messages may include any HTML (Hypertext Markup Language) hypermedia elements, such as links to other resources on the World Wide Web, images, movies and sound files.

ZENO places issues, positions and arguments into a 'picture' which is richer, more precise and focused than the "thread" mechanism typical of news groups. This structure provides a view on the messages which substantially facilitates the browsing and retrieval of relevant past contributions to the discussion. Alternative solutions (i.e. positions) proposed for issues can be prioritized. Using reason maintenance and constraint satisfaction procedures, the preferences expressed in the arguments brought forward by the participants are summarized.

The ZENO server is a piece of software written in Java. This will eventually allow it to be used with a variety of World Wide Web servers and operating systems. The index produced by ZENO is stored in a relational database, allowing messages and the argumentation elements within messages - such as issues, positions, and arguments - to be selected, filtered and sorted using standard SQL queries (Structured Query Language); thus, any SQL-database can be used with the ZENO server. The ZENO server hides the SQL-technicalities from the user. The use of established database technology provides transaction control and improved security. User management and password protection can be easily implemented.

ZENO will be further developed as part of GEOMED (GEOgraphical MEDiation), which is a new project financed by the European Commission within the Telematics Applications Programme. Urban and regional planning, and environmental assessment procedures have been selected as pilot applications. Using the World Wide Web as basic infrastructure, the project implements a distributed system that provides open access to data from Geographical Information Systems (GIS) for public planning and political decision making.

Three major components are currently envisioned: Information services will provide easy and cost-effective access to distributed, heterogeneous geographical databases. This includes facilities for finding relevant GIS data, converting proprietary GIS data to standard formats for data interchange, as well as ways of viewing and browsing GIS data from within Web browsers. Many of these functions will be implemented using custom GIS applets written in Java.

Documentation services will provide a `shared workspace' for storing and retrieving documents and messages related to particular geographical planning projects. This will be a convenient way for ordinary users to add information to the hyperspace of documents available on the network. GEOMED plans to integrate the BSCW system (Basic Support for Cooperative Work) which was originally developed at GMD and which is being evolved in a separate European Commision project entitled CoopWWW (Interoperable Tools for Cooperation Support using the World Wide Web)

ZENO provides the basis for the mediation services being developed in GEOMED. Pilot applications in real life urban and regional planning processes will guide the evolution of ZENO's functionality, as it complements the information and documentation services within GEOMED. As part of a feasibility study for GEOMED, a model was created in cooperation with the City of Bonn to demonstrate ZENO's potential benefits as a mediator's assistant: the documents of a five-year regional planning project were modeled as ZENO messages. Turning from retrospective modeling to actual `real time' use in GEOMED, the ZENO demonstrator is now being extended to cover related segments of the new high speed train line connecting Cologne and Frankfurt. The basic version of the integrated services will be available for pilot applications in the second quarter of 1997.

The GEOMED consortium consists of Intecs Sistemi, Coordinator (Italy), GMD, Technical Director (Germany), Intrasoft (Greece), Vrije Universiteit Brussel (Belgium), TNO-Physics and Electronics Laboratory (Netherlands), TNO-Building and Construction Research (Netherlands), City of Bonn (Germany), City of Tilburg (Netherlands), Tuscany Region (Italy) and the Technical Chamber of Greece (Greece).

The ZENO project on the Web:

Please contact:
Thomas Gordon - GMD
Tel: +49 2241 14 2665

return to the contents page