tim@LINC.CIS.UPENN.EDU (Tim Finin) (03/17/87)
Colloquium
Computer and Information Science
University of Pennsylvania
"Applying Relevant Precedents in a Case-Based Reasoning System"
Kevin D. Ashley
Department of Computer and Information Science
University of Massachusetts at Amherst
The law is an excellent domain to study Case-Based Reasoning (``CBR")
problems since it espouses a doctrine of precedent in which prior
cases are the primary tools for justifying legal conclusions. The law
is also a paradigm for adversarial CBR; there are ``no right answers",
only arguments pitting interpretations of cases and facts against each
other.
This talk will demonstrate techniques employed in the HYPO program for
representing and applying case precedents and hypothetical cases to
assist an attorney in evaluating and making arguments about a new fact
situation. HYPO performs case-based reasoning and, in particular,
models legal reasoning in the domain of trade secrets law. HYPO's key
elements include: (1) a structured case knowledge base (``CKB") of
actual legal cases; (2) an indexing scheme (``dimensions") for
retrieval of relevant precedents from the CKB; (3) techniques for
analyzing a current fact situation (``cfs"); (4) techniques for
``positioning" the cfs with respect to relevant precedent cases in the
CKB and finding the most on point cases (``mopc"); (5) techniques for
manipulating cases (e.g., citing, distinguishing, hybridizing); (6)
techniques for perturbing the cfs to generate hypotheticals that test
the sensitivity of the cfs to changes, particularly with regard to
potentially adverse effects of new damaging facts coming to light and
existing favorable ones being discredited; and (7) the use of ``3-ply"
argument snippets to dry run and debug an argument.
An extended example of HYPO in action on a sample trade secrets case
will be presented. The example will demonstrate how HYPO uses
``dimensions", ``case-analysis-record" and ``claim lattice" mechanisms
to perform indexing and relevancy assessment of precedent cases
dynamically and how it compares and contrasts cases to come up with
the best precedents pro and con a decision.
March 20, 1987
3:00 to 4:30
Room 216
Refreshments Available
2:30-3:00
Faculty Lounge