Barbara J. Grosz
Division of Engineering and Applied Sciences
Harvard University
33 Oxford Street
Cambridge MA 02138
Phone: (617) 495-3673
Fax: (617) 496-1066
E-mail:grosz@eecs.harvard.edu
URL: http://www.eecs.harvard.edu/grosz/
Research Topic Area: Collaborative Planning
Key words: collaboration, multi-agent systems, human-computer interfaces
Collaborative Plans and Collaborative Communication Systems
Project Summary
As computer systems become ubiquitous and more information becomes available electronically, it is increasingly important for computer systems to be able to collaborate with each other and their users. The development of the underlying theories and formalizations needed
to build collaborative systems will have far-reaching practical import
as well as addressing challenging computer science problems. The
SharedPlan formalization of collaboration (Grosz & Kraus, 96) provides
a specification of the capabilities to act and mental attitudes that
agents must have to participate in collaborative activities with one
another. We are extending this formalization by developing strategies
for elaborating partial plans and by specifying axioms that treat more
completely the attitude of {\it intending that} a proposition hold
(Grosz & Kraus, 1997). These extensions were incorporated into an
initial system of collaborting agents (Pasula, 1996), and experience
with that implementation is informing modifications to the theory.
In addition to work on the basic theory of collaborative activity, we
are designing a collaborative communication system based on
SharedPlans; this system will both demonstrate the value of a model of
collaboration to the design of human-computer interface systems and
test the formalization. In a theory of discourse structure, developed
with Sidner (Grosz & Sidner, 1986}, we distinguish among three components
of discourse structure: linguistic structure, intentional structure,
and attentional state. The grouping of utterances into discourse
segments forms the basis of the linguistic structure. Discourse
segment purposes and the relations between them form the intentional
structure. Attentional state, an abstraction of the discourse
participants' focus of attention, records the objects, properties, and
relations that are salient at a given point in the discourse. Our
research on this grant addresses the intentional component and connects
with earlier work showing that SharedPlans are the appropriate basis for
modeling intentional structure (Lochbaum, 1995).
We developed a simple SharedPlan-based interface system to a
``ubiquitous information system'' containing information about courses
and fields of study; two kinds of uses of the system --- course review
and term-paper preparation --- were explored. Our experience with
these pilot implementations and analysis of the differences between
the two tasks is being used in developing a new system. We also note
that Rich and Sidner are using our formalization for their work in
collaborative direct-manipulation interfaces (Rich & Sidner, 1996).
We expect this research to contribute to the development of computer
agents that are fully collaborative, with each other and their users,
and to enable the construction of more flexible and user-friendly
interfaces.
Project References:
- Grosz, Barbara, and Sarit Kraus. ``Collaborative Plans for Complex Group Action.'' In Artificial Intelligence, 86(2), 269-357 (1996).
- Grosz, Barbara J. and Sarit Kraus. ``The Evolution of {S}hared{P}lans." Manuscript in preparation (1997).
- Lochbaum, Karen E. ``The Use of Knowledge Preconditions in Language Processing.'' In Proceedings of the International Joint
- Conference on Artificial Intelligence (IJCAI-95)}, Vol. 2, 1260-1266 (1995). Pasula, Hanna. ``Design of a Collaborative Planning System.'' Harvard University, Senior Honors Thesis (1996).
Background References:
- Grosz, Barbara, and Candace Sidner. ``Attention, Intentions, and
the Structure of Discourse.'' In Computational Linguistics,
12(3), 175-204 (1986).
- Grosz, Barbara, Karen Lochbaum and Candace Sidner. ``Models of
Plans to Support Communication: An Initial Report.'' In
Proceedings of the 8th National Conference on Artificial Intelligence
(AAAI-90), 485-490 (1990).
- Grosz, B.J., M. Pollack and Sidner, C. ``Computational Models of
Discourse'', in Michael Posner (ed), Foundations of Cognitive
Science, MIT Press, Bradford Books, 1989.
- Lochbaum, Karen E. ``An Algorithm for Plan Recognition in
Collaborative Discourse.'' In Proceedings of the 29th Annual Meeting
of the ACL, 33-38 (1991).
- Rich, C. and C. L. Sidner. ``Adding a Collaborative Agent to
Direct-Manipulation Interfaces.'' In Mitsubishi Electric Research
Laboratories, May, 96-11 (1996).
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