Realization

For each of the levels or facets indicated, that is modeling, realization and architecture, we will briefly describe the way we plan to tackle the problems involved.

Modeling the behavior of cooperative agents

Our approach will be based on the work already done in the context of DESIRE  [Desire,KAW95,Multiagents,Compositional]. In effect, DESIRE provides a compositional modeling framework in which the cooperation between multiple components can be expressed in a declarative manner (with temporal semantics  [KAW96,JELIA94,ECAI94,META94]). In particular, DESIRE has been employed for describing cooperative multi-agent systems for project coordination, negotiation and monitoring processes  [Modeling,ModelAge96,ModelAge97,ATAL96,ICMAS96,Cooperation]. Research in this area will be focussed on defining cooperation in information-retrieval tasks and on expressing user-preferences and information-needs in an adequate way. Other topics of interest include modeling users as agents and the verification of agent specifications.

Realizing Web-aware agents

The development of Web-aware applications has been addressed in the DejaVu project  [Applications,Music]. The approach taken there was to employ object-oriented design technology for realizing a component-based approach to integrating multimedia in Web-based hypermedia applications. The development of generic components for realizing agent-based systems will be addressed in the same fashion, in order to allow for the integration of adequate multimedia and graphical user interface support.

It is our intention to employ the distributed logic programming language DLP  [DLP] as a high-level vehicle for programming the behavior of agents. We strive on the one hand for a close integration of the DESIRE framework and DLP and on the other hand to extend DLP with the primitives needed to access the Web and to create adequate graphical and multimedia user interfaces.

Architectural support

To support cooperating agents over a network we need to provide point-to-point communication as well as event-based notification. We intend to use the Orbix/CORBA Object Request Broker as an object-level mediator for the communication between agents and the communication of agents with Web server and client applications.

Currently, we are actively employing Orbix/CORBA to develop an workbench for groupware task analysis and a distributed architecture for visualisation (DIVA).

To allow for managing the information retrieval and management tasks involved in dealing with the Web, helper applications must be developed which employ the native HTTP protocol of the Web, and which perform automatic Web navigation. Such tools are often called robots or spiders. An information retrieval tool  [Bra,Fish,Search] has been developed at the TUE. Two implementations of this tool exist: one which is integrated in a WWW browser, and one which is a CGI-script for use on servers. The latter implementation now exists in a multi-threaded version, using multiple search-agents operating in parallel. Current Web developments make it possible to integrate such agents into browsers in a flexible way by means of applets or plug-ins. For server-based applications servlets or server plug-ins can be used to avoid the overhead generated by the CGI protocol and by invoking individual instantiations of CGI-scripts.

A method for improving the use of the internal structure of documents has been defined and implemented by means of object-oriented databases. An intelligent retrieval helper application needs to be aware of the internal structure of documents, and needs to be able to store the information it finds using a similar structure. Also, it needs to have direct access to the links between documents; this information is embedded within the text of the documents. A Web-server based on the object-oriented database Ode has been developed for this purpose  [OODB]

Pamela

First of all, it must be remarked that the target system Pamela is explicitly intended to stimulate and regulate the cooperation between the participating research groups.

As concerns its functionality, the final version of Pamela should include

A more detailed specification of its functionality, however, must be considered as one of the tasks of the project.

Discussion

As concerns technology, the realization of WASP (and in particular Pamela) is based on the programming language DLP (extended with Internet capability), and the facilities provided by the hush library and its extensions (both developed by SE/VU, see refs [17,19,20]).

In addition, at the level of design, we exploit DESIRE (developed by AI/VU, see refs [1,2,16,22] of the proposal). In effect, the integration these technologies (DESIRE and DLP) contributes to the originality of our approach.

From an architectural point of view our approach is basically a client-server architecture, with agents as user-dedicated clients. For the communication and Internet capabilities we exploit existing technology (TCP/IP, HTTP, CORBA).

Needless to say that we wish to maintain a close integration between the efforts involved in the research concerning the aspects mentioned. In particular, we intend to develop a prototype agent application Pamela (Personal Assistent for Managing Electronic Archives) as a point of reference and as a means of coordinating the research done by the parties involved. In addition, the Pamela application will serve as means to demonstrate the power of our approach to the scientific community and the rest of the world.