Professor
Computer Science Department
Rochester, NY 14627-0226
Email: lastname AT cs DOT rochester DOT edu
Fax: (585) 273-4556
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. I am also a
member of the Center
for Language Sciences (CLS) and the Center
for Computation and the Brain.
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;
- Deriving general
world knowledge from texts and taxonomies, as an attack on the
"knowledge acquisition bottleneck" in AI; the current system is
called KNEXT
(KNowledge EXtraction from Text).
- 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 plans of action in a transportation domain);
automatically discovering invariants in planning domains -- see
the DISCOPLAN
system; solving the Frame Problem using "explanation closure".
Office hours, Spring 2008:
Tuesday and Thursday, 1:00-2:00 (tentative)
Current and recent courses:
CSC 190A/290A (Topics in Computer Science): Machines and Consciousness
CSC 244/444: Logical Foundations of Artificial
Intelligence
CSC 247/447: Natural Language Processing
CSC 280: Computer Models and Limitations
CSC 242: Artificial Intelligence
Present research collaborators:
James Allen: Dialogue processing, agents
Greg Carlson:
(Linguistics) Mining general world knowledge from texts
Henry Kyburg: Mining general world knowledge from texts
Alfonso Gerevini (U. Brescia):
Scalable temporal reasoning, efficient planning, inferring state invariants
in planning
Proshanto Mukherji: Discovery of state invariants in
planning domains by exploration
Phil Michalak: General knowledge abstraction from
texts, plan/goal recognition
Tom Weingarten (weingart@cs.rochester.edu), URCS undergraduate:
Using pulse train to compute probabilities in Bayesian networks
Some past research collaborators:
David Ahn: (Ph.D. 2004, now a Natural Language Scientist at Powerset (LinkedIn):
Semantics/pragmatics of adverbially quantified sentences
Teresa Zollo: (Ph.D. 2003, now at SUNY Geneseo --
new URL):
Recovery from speech recognition errors
Matthew Tong:
(B.Sc. 2003, now a doctoral student in
Computer Science at UCSD):
Mining general world knowledge from texts
Amon Seagull (Ph.D. 2000, now at Nova Southeastern
University, Florida, new URL):
Well-foundedness and reliability in natural language parsing
Aaron Kaplan:, (Ph.D. 2000, now at XRCE, Grenoble,
Content Analysis team):
A computational model of belief
Mark Core (Ph.D. 2000, now at U. Edinburgh,
Human Communication Research Centre
):
Dialog parsing: From speech repairs to speech acts
Marc Light (Ph.D. 1995, now at Mitre):
Morphological cues for lexical semantics
Massimo Poesio (Ph.D. 1994, now at U. of Essex, U.K.):
Assigning semantic scope to operators in dialogues
Chung Hee Hwang (Ph.D. 1992, now at Motorola's Intelligent Systems Lab in
Phoenix, AZ):
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. Toronto):
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"
Selected Publications
(underlined titles provide pdf files in most cases)
- F. Morbini and L.K. Schubert,
"Metareasoning as an integral
part of commonsense and autocognitive reasoning", AAAI'08
Workshop on Metareasoning, July 13-14, 2008, Chicago, pp 155-162.
- Benjamin Van Durme, Ting Qian and Lenhart K. Schubert,
"Class-driven attribute extraction",
COLING'08, Aug. 18-22, 2008, Manchester, UK.
- Benjamin Van Durme and Lenhart K. Schubert,
"Open knowledge extraction using compositional
language processing", Symposium on Semantics in Systems for Text
Processing (STEP 2008), September 22-24, 2008 - Venice, Italy.
- F. Morbini and L.K. Schubert,
"Towards
realistic autocognitive inference", Logical Formalizations
of Commonsense Reasoning, Papers from the AAAI Spring Symposium,
Tech. Rep. SS-07-05, AAAI Press, Menlo Park, CA, March 26-28,
Stanford, pp. 114-118, 2007.
- L.K. Schubert,
"Turing's
dream and the knowledge challenge", 21st Nat. Conf. on
Artificial Intelligence (AAAI'2006), July 16-20, 2006, Boston,
MA, AAAI Press, Menlo Park, CA, pp. 1534-8.
- L.K. Schubert,
"Some
KR&R requirements for self-awareness", 2005 AAAI Spring Symposium on
Metacognition in Computation, Stanford University, March 21-23, 2005.
- L.K. Schubert, ``A new characterization of
probabilities in Bayesian networks", Uncertainty in AI: Proc.
of the 20th Conference (UAI 2004), Banff, Canada, July 7-11.
Extended version forthcoming as tech. rep., Dept. of Comp. Sci.,
Univ. of Rochester, Rochester, NY 14627-0226.
- L.K. Schubert, "Implicit Skolemization:
Efficient reference to dependent entities", Research on
Language and Computation 5, April 2007, (special volume on
Binding Theory, ed. by Alastair Butler, Ed Keenan, Jason Mattausch
and Ken Shan), pp. 69-86. Pre-publication
version (differing only in format).
- L.K. Schubert and M.H. Tong, ``Extracting
and evaluating general world knowledge from the Brown corpus",
Proc. of the HLT/NAACL 2003 Workshop on Text Meaning, May 31,
Edmonton, Alberta, Canada. (postscript)
- L.K. Schubert, ``Can we derive general
world knowledge from texts?", M. Marcus (ed.), Proc. of the
2nd Int. Conf. on Human Language Technology Research (HLT 2002),
March 24-27, San Diego, CA, pp. 94-97.
(postscript)
- L.K. Schubert, "The situations we
talk about", in J. Minker (ed.), Logic-Based Artificial
Intelligence,
Kluwer,
Dortrecht, 2000, 407-439. (postscript)
- A.N. Kaplan and L.K. Schubert,
"A
computational model of belief", Artificial Intelligence 120(1),
June 2000, 119-160.
- A. Gerevini and L.K. Schubert,
"Discovering state constraints
in DISCOPLAN: Some new results", Proc. of the 17th Nat. Conf. on
Artificial Intelligence (AAAI'2000), July 30-August 3, 2000,
Austin, Texas.
- L.K. Schubert and C.H. Hwang,
"Episodic Logic meets Little Red
Riding Hood: A comprehensive, natural representation for language
understanding", in L. Iwanska and S.C. Shapiro (eds.), Natural
Language Processing and Knowledge Representation: Language for Knowledge
and Knowledge for Language, MIT/AAAI Press, Menlo Park, CA, and
Cambridge, MA, 2000, 111-174. See
MIT Press website for the book.
- L.K. Schubert, "Dynamic
Skolemization", in H. Bunt and R. Muskens (eds.),
Computing Meaning, vol. 1, Studies in Linguistics & Philosophy
Series, Kluwer Academic Press, Dortrecht (also Boston, London), 1999,
219-253.
- A. Gerevini and L.K. Schubert,
"Inferring state constraints for domain-independent planning",
Proc. of the 15th Nat. Conf. on Artificial Intelligence (AAAI-98),
July 26-30, Madison, WI, 1998.
- M.G. Core and L.K. Schubert, "Implementing parser metarules that handle
speech repairs and other disruptions", 11th Int. FLAIRS Conference,
Special Track on Natural Language Processing and Human-Computer
Interaction, Sundial Beach, Florida, May 17-20, 1998.
- 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. Reprinted with
minor changes in H.J. Levesque and F. Pirri (eds.), Logical
Foundations for Cognitive Agents: Contributions in Honor of Ray
Reiter, Springer, Berlin, 1999, pp. 325-351.
- 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.
- L.K. Schubert,
"Monotonic solution of the frame problem in the situation calculus:
An efficient method for worlds with fully specified actions,"
in H. Kyburg, R. Loui and G. Carlson (eds.), Knowledge Representation
and Defeasible Reasoning, Kluwer, Dortrecht, pp. 23-67, 1990.
(A pdf
version is also available.)