HERMES - Supporting Argumentative Discourse in Multi-Agent Decision
Making
by Nikos Karacapilidis
Multi-agent decision making is usually performed in the presence
of ill-structured information, brought up by parties with different backgrounds
and interests. In such environments, argumentative discourse may provide
agents a means of pursuing their own objectives, by arguing in favour or
against one's assertions, and resolving conflicts through iterative knowledge
retrieval.
HERMES is a Web-based system that supports argumentative discourse in
group decision making. The system organizes the existing knowledge in a
discussion graph, which consists of issues, alternatives, positions and
preference relations (see Figure). It provides means of expressing and
weighing individual arguments and preferences, in order to support or challenge
the selection of a certain choice. The system supports defeasible and qualitative
reasoning. Argumentation is performed through a set of discourse acts which
call a variety of procedures for the propagation of information in the
corresponding discussion graph. Unlike most Web-based conferencing systems
which merely provide threaded, hierarchical discussion forums, HERMES includes
reasoning mechanisms that monitor the discussion, performing consistency
checking and constantly updating the status of the discourse. The system
focuses on distributed, asynchronous collaboration, allowing agents to
surpass the requirements of being in the same place and working at the
same time. It is fully implemented in Java applets (there is no need for
the users to download the system), and can be run on the World-Wide Web
using any standard browser.
In general, it is very difficult to completely automate the processes
involved in argumentative discourse in such environments. HERMES rather
acts as an assistant and advisor, by facilitating communication and recommending
solutions, but leaving the final enforcement of decisions to the agents.
The use of information technology may assist in various ways. One important
goal for us was to provide easy access to the current knowledge, at any
time. Another was to provide direct computer support for the argumentation
process. In argumentative discourse, the quality and acceptability of decisions
depends not only on the availability of accurate information, but also
on the fairness and openness of the procedure. For example, when planning
a site for storing hazardous wastes, the interests of the affected communities,
environmental protection groups and local industries are likely to be in
conflict. Involving representatives of these diverse interests in the decision
making process at the earliest possible stage, can facilitate the extraction
of a better plan and increase its approval by the interested parties. We
have planned to evaluate the system with a real application on preventive
medicine, starting at the end of 1997.
Future work involves implementation of an already specified framework
where CBR and Argumentation Based Reasoning jointly aid the users to address
various discourse instances. Use of precedent cases is well-suited in argumentation
systems. Cases in our model are not merely considered as representations
of past data, but as flexible entities associated with the underlying viewpoint
of a user and the evolution of the corresponding discussion. We also plan
to work on the application of linguistic labels to various argumentation
elements. According to this approach, decision makers may assert the extent
they are prepared to accept the arguments asserted by the others and the
importance of each argumentation element. Finally, we intend to keep the
work going on the application of measures of similarity between these elements,
aiming at providing estimations of conflict or consensus between the decision
makers involved. For more information on HERMES, see: http://aid.inria.fr/hermes/hermes_overview.html
Please contact:
Nikos Karacapilidis - Swiss Technological Institute of Technology
Tel: +41 21 693 2576
E-mail: Nikos.Karacapilidis@di.epfl.ch
