WASP -- Web Agent Support Program
8. Content
In this section we describe the underlying scientific
problem our project is concerned with, and
we will further detail the method(s) we will employ,
and the expected results. In addition we will explain
the relevance of our contribution for the scientific
community and we will assess our project with respect to
its scientific merits.
a. Scientific Problem
The notion of agents has become a powerful metaphor
for designating quasi-autonomous intelligent processes
that aid the user in managing the complexity
of a variety of tasks, including information retrieval,
activity scheduling and process monitoring.
Our project aims at providing insight in and solutions
for
- modeling the behavior of cooperating agents
- generic means for realizing actual agents in a Web-aware context
- architectural support for programming agent-based systems
In effect, agents have been characterized
as the dominant human-computer interface of the future [Negro].
The aspects of our research as indicated above
address the problems involved in defining and realizing
the potential of the agent metaphor as a
human-computer interface in the distributed information
system domain, in particular the Web.
Modeling agent behavior
The ability to model the behavior of solipsistic
and cooperative agents is a prerequisite for
(a) managing the complexity of defining agent behavior,
and (b) for adapting the behavior of agents to
user preferences or circumstantial conditions.
Realizing agents
We chose for aiming our project at realizing
agents in a Web-aware context
(a) because the Web provides a rich reservoir
of information,
and (b) the Web offers a suitable infrastructure
for defining an actual graphical user interface
for employing agents.
In particular, agents may be integrated with
standard means for accessing the Web by means
of applets.
In particular we wish to provide 'standard' components
for creating agent-based systems
(including support for graphical user interfaces,
access to the Web and cooperation).
Architectural support
The architectural requirements for realizing agents
in a Web-aware context consists of
(a) a high-level distributed language or system for
programming the behavior of agents,
and (b) access to the Web both in terms
of server-side and client-side computation.
The cooperation between agents and other
components of an application requires advanced
means for distributed object creation and interaction.
Discussion
Currently agents are in the focus of interest
of numerous research groups
[Internet,Softbots,Software,Architecture,Survey].
However, one may observe a divergence between
purely formal approaches and purely pragmatical
approaches, that provide an operational realization
of agents lacking a solid foundation.
Although many of the ideas and concepts
underlying agents have been a topic of
research for decades, notably issues
concerning distributed systems and
programming language design, the notion of agents
itself hase become a major research topic
only recently.
A survey of agent theories, architectures
and languages is given in [Survey].
As concerns agent theories, the main focus of
attention lies on a logical analysis
of intentional notions underlying the behavior
of single agents, whereas for agent architectures
issues of communication and cooperation between agents seem
to be more important.
In [Survey], concurrent logic programming languages
are considered to be the ancestors of agent languages.
Of immediate relevance for our own work is the
Oasis programming language described in [Oasis],
which bears a close resemblance to the
distributed logic programming language DLP [DLP].
Recently, commercial agent systems have been developed for the Web.
For example, General Magic has launched its
Telescript Agent System, a system that employs
mobile agents defined in General Magic's Telescript language.
Also in [Internet], a number of agent-like programs
are described.
We are reluctant to qualify these systems as 'agents',
however, since they are defined in a purely operational way.
We find, for complex agents anyway, a more explicit
representation of the intentional aspects desirable.
In a recent issue of the CACM( 37(7), July 1994),
some current trends and applications of agent research
are presented.
From our perspective we consider as important representatives
of ongoing research:
[Software],
that describes the agent communication language
KQML (Knowledge Query and Manipulation Language);
[Architecture], which describes the complexity of of integrating
collections of agents;
and [Softbots], which describes a number of simple agents
for facilitating access to the Web.
b. Method
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].
In effect, DESIRE provides a logic-based
formalism in which the cooperation between
multiple components can be expressed in a declarative,
compositional
way. In particular, DESIRE has been
employed for describing cooperative multi-agent systems
for monitoring processes [Modeling,ModelAge,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.
Architectural support
In the DejaVu project we have already gained
expertise in the area
of language embedding and integration [DLP,Hush,VE95].
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.
Also, we have gained some expertise in
supporting cooperative work [Chatting].
This work needs to be extended to allow for
agents to join a session in which they may
communicate and cooperate.
In addition, 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.
An information retrieval tool [Bra,Fish,Search]
has been developed at the TUE and integrated into a WWW browser.
This tool is also available as a server-side tool.
The latest version uses multiple search-agents operating in parallel.
Current Web developments make it possible to integrate agents into
browsers in a more flexible way, by using applets or plug-ins.
A method for improving the use of the internal structure of documents
has been defined 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 in a similar structure. A Web-server based on an
object-oriented database [OODB]
has been developed for this purpose.
Discussion
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.
c. Results
The WASP project is aimed to result in
a framework (in its extended meaning) for the
development of agent-based Web-aware applications.
Such a framework includes:
- a methodology for developing agent-based applications, as well as
- a logical foundation for modeling agent behavior; and in addition
- guidelines for realizing actual agent applications, and
- software components that can be used as building blocks, including
- a language for programming agent behavior.
In addition we wish our work to result in a generic
agent application Pamela that demonstrates the
capabilities of our approach.
The intended results, divided over the various aspects
of our project, are summarized below.
Modeling the behavior of cooperative agents
- a formalism for modeling cooperative agents
- logical foundations of agent behavior
- modeling user preferences in information retrieval
- modeling circumstantial awareness and negotiation
Realizing Web-aware agents
- generic agent software components
- user interface components for managing agents
- communication primitives for agent communication
- guidelines for developing agent systems
Architectural support
- an agent-based programming language
- a high-level API for Web-aware applications
- an object-based framework for distributed agent applications
- tools for agent-based information retrieval and management
d. Contribution
Scientifically, our work is of significance for the
areas of
- information and knowledge-based systems,
- user-interface development, and
- object-oriented software engineering.
In particular, because we propose to take
an integrated approach to the problem of providing
agent support for Web-aware applications,
the efforts coming from the different areas
of expertise of the participants
results, hopefully, in a more encompassing
theoretical and practical framework
than would have been possible for each
of the participants individually, or more in general
in a more mono-disciplinary approach.
3. Merits
Clearly our project covers both fundamental
and pragmatic aspects.
It is application-oriented in the sense that
it is aimed at satisfying the conditions
for developing actual agent-based applications.
However, it is fundamental to the extent
that it is based on well-founded
principles of modeling and software engineering.
In the area of information retrieval, moreover,
we hope to come up with a substantially
new approach for the discovery of new (recent) interesting
and relevant information in a large distributed hypermedia
information system such as the Web.
mailto:eliens@cs.vu.nl
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Thu Sep 26 14:04:33 MET DST 1996
)