Professor
Computer Science Department
Rochester, NY 14627-0226
Email: schubert@cs.rochester.edu
Fax: (716) 461-2018
http://www.cs.rochester.edu/u/schubert/
Ph.D. (1970) University of Toronto. Assistant Professor
(73-77), Associate Professor (77-84), Professor (84-88); University of
Alberta. Professor (88-present), University of Rochester.
My research interests center around language, knowledge
representation, inference and planning. These interests are tied
together by the general goal of developing agents with common sense
and the ability to converse and acquire knowledge through language.
Some specific topics my students and I have worked on include
- very expressive, language-like logics to capture the content of
ordinary language and commonsense reasoning as directly as possible;
the most recent is called Episodic Logic;
- semantics of events/situations, tense/aspect, reference, affixes,
mass terms, generic sentences, belief, questions, vagueness;
- efficient, specialized inference techniques for taxonomies,
part-structure, temporal relations, and other classes of relations
that pervade commonsense knowledge and are handled effortlessly
by people;
- methods of organizing knowledge and inference so that a
general-purpose reasoner will easily locate knowledge relevant to
a particular task (even for a very large knowledge base), and will
smoothly integrate general and specialized inference techniques;
- strategies for human-like, error-tolerant natural language parsing
and disambiguation, and for mapping syntactic structure to a
representation of the underlying meaning (allowing for context);
- development of implementations of the above knowledge representations
and inference techniques; the latest is called
EPILOG, and supports
the Episodic Logic knowledge representation and integrates general
and specialized inference mechanisms;
- reasoning about plans and actions, in support of both language
understanding (e.g., conversation planning and inferring the
goals and plans of story characters) and domain reasoning
(e.g., formulating transportation plans in the TRAINS domain);
solving the Frame Problem using "explanation closure".
Office hours:
3:30 - 4:30 Tuesday and Thursday
Recent courses:
CSC 242: Artificial Intelligence
CSC 244/444: Logical Foundations of AI
CSC 247/447: Natural Language Processing
Present research collaborators:
James Allen: Dialogue processing, planning
Aaron Kaplan:: A computational model of belief
Mark Core: Dialogue parsing
Amon Seagull: Disambiguation
Alfonso Gerevini (U. Brescia): Scalable temporal reasoning, efficient planning
Some past research collaborators:
Marc Light (Ph.D. 1995, now at U. Tuebingen):
Morphological cues for lexical semantics
Massimo Poesio (Ph.D. 1994, now at U. Edinburgh):
Assigning semantic scope to operators in dialogues
Chung Hee Hwang (Ph.D. 1992, now at MCC Austin):
A logical approach to narrative understanding, Episodic Logic
Alice Kyburg (Ph.D. 1994, now at U. Wisconsin at Oshkosh):
Pragmatic and semantic accounts of vagueness
Stephanie Schaeffer (M.S. 1988, systems prog., 1988-92, U. Alberta):
Temporal reasoning, hybrid reasoning, EPILOG development
Jeffry Pelletier (U. Alberta):
Semantic interpretation, semantics of mass terms and generics
Fahiem Bacchus (Ph.D. 1988, now at U. Waterloo):
Representing and reasoning about probabilistic knowledge
Caoan Wang (Ph.D. 1988, now at Memorial U. of Newfoundland):
Computational geometry
Professional activities and awards
KR'98 program co-chair
ACL'93 program chair
CSCSI'80 program chair
JAIR editorial board (1996-pres)
Computational Intelligence editorial board (1985-pres)
Computational Linguistics editorial board (1983-5)
Fellow of the AAAI (elected in 1993 for "fundamental contributions in NLP,
esp. in the formalization, representation, and practical implementation
of non-first order concepts")
Alexander von Humboldt Fellow (1978-9)
Associate of the Canadian Institute for Advanced Research (1985-88)
Outstanding Contribution award for the KR'89 paper (with C.H. Hwang),
"An episodic knowledge representation for narrative texts"
Recent Publications
L.K. Schubert, "Dynamic Skolemization", in H. Bunt and R. Muskens (eds.),
Computational Semantics, Studies in Linguistics & Philosophy
Series, Kluwer, to appear.
M.G. Core and L.K. Schubert, "Handling speech repairs and other
disruptions through parser metarules", AAAI Spring Symposium on
Computational Models for Mixed Initiative Interaction, Mar. 24-16,
Stanford U., 1997.
M. Light and L.K. Schubert, "Knowledge representation for lexical
semantics: Is standard first-order logic enough?", in H. Bunt,
L. Kievit, R. Muskens, and M. Verlinden (eds.), IWCS II: 2nd Int.
Workshop on Computational Semantics, Tilburg University, Netherlands,
Jan. 8-10, 1997.
A. N. Kaplan and L.K. Schubert, "Simulative inference in a computational
model of belief", in H. Bunt and R. Muskens (eds.), Computational
Semantics, Studies in Linguistics & Philosophy Series, to appear.
Preliminary version in H. Bunt, L. Kievit, R. Muskens, and M. Verlinden
(eds.), IWCS II: Second International Workshop on Computational Semantics,
Tilburg University, Netherlands, Jan. 8-10, 1997. Expanded version in
Tech. Rep. 636, Dept. of Computer Science, U. Rochester, Rochester, NY
14627-0226, October 1997.
L.K. Schubert, "Framing the donkey: Towards a unification of semantic
representations with knowledge representations", AAAI Fall Symp. on
Knowledge Representation Systems based on Natural Language, Nov. 9-11,
Cambridge, MA, 1996.
A. Gerevini and L.K. Schubert, "Accelerating partial-order planners:
Some techniques for effective search control and pruning", J. of
Artificial Intelligence Research 5, pp. 95-137, Sept. 1996.
D. Traum, L.K. Schubert, M. Poesio, N. Martin, M. Light, C.H. Hwang,
P. Heeman, G. Ferguson, J.F. Allen, "Knowledge representation in the
TRAINS-93 conversation system", Int. J. of Expert Systems 9(1),
special issue on Knowledge Representation and Inference for Natural
Language Processing, pp. 173-223, 1996.
A. Gerevini and L.K. Schubert, "Computing parameter domains
as an aid to planning", Proc. of the 3rd Int. Conf. on Artif. Intell.
Planning Systems (AIPS-96) (B. Drabble, ed.), May 29-31, Edinburgh,
The AAAI Press, Menlo Park, CA, pp. 94-101., 1996.
L.K. Schubert and A. Gerevini, "Accelerating partial order planners
by improving plan and goal choices", Proc. of the 7th Int. Conf.
on Tools with AI (ICTAI'95), Nov. 5-8, Herndon, VA, 1995, pp. 442-450.
Gerevini, A. and L. K. Schubert. ``Efficient algorithms for
qualitative reasoning about time", Artificial Intelligence 74(2),
pp. 207-248, 1995.
J.F. Allen, L. K. Schubert, G. M. Ferguson, P. A. Heeman,
C. H. Hwang, T. Kato, M. Light, N. G. Martin, B. W. Miller,
M. Poesio, and D.R. Traum. "The TRAINS project: A case study in
building a conversational planning agent," J. Experimental and
Theoretical Artificial Intelligence 7, 7-48, 1995.
C.H. Hwang and L. K. Schubert. "Interpreting tense, aspect,
and time adverbials: a compositional, unified approach'', in D.M.
Gabbay and H.J. Ohlbach (eds.), Proc. of the 1st Int. Conf. on
Temporal Logic, July 11-14, Bonn, Germany, Springer-Verlag, pp. 238-264,
1994.
L.k> Schubert, "Explanation closure, action closure, and the
Sandewall test suite for reasoning about change", J. of Logic and
Computation 4(5), Special Issue on Actions and Processes, pp. 679-799,
1994.
A. Gerevini, L.K. Schubert, and S. Schaeffer. "The temporal
reasoning tools TimeGraph-I-II.'' Proc. of the 6th IEEE Int. Conf.
on Tools with Artificial Intelligence, Nov. 6-9, New Orleans,
Louisiana, 1994.
C.H. Hwang and L.K. Schubert, "Meeting the interlocking needs
of LF-computation, deindexing, and inference: An organic approach
to general NLU.'' In Proc. 13th Int. Joint Conf. on Artificial
Intelligence, August, 1993.
C.H. Hwang and L.K. Schubert, "Episodic Logic: A situational
logic for natural language processing," In P. Aczel, D. Israel,
Y. Katagiri, and S. Peters (eds.), Situation Theory and
its Applications 3 (STA-3), CSLI, 307-452, 1993.
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