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Available abstracts for the Reports

Name:
bdp/bdp-fall93.ps.gz
Title:
A Strategic Metagame Player for General Chess-Like Games
Author:
Barney Pell (bdp) <pell@ptolemy.arc.nasa.gov>
Format:
gzip'ed Postscript
Date:
October, 1993.
Details:
Appeared in Proceedings of the AAAI Fall Symposium on Games: Learning and Planning, Raleigh, NC: October 1993.
This paper reviews the concept of Metagame and discusses the implementation of \metagamer\, a program which plays Metagame in the class of symmetric chess-like games which includes chess, Chinese-chess, checkers, draughts, and Shogi. The program takes as input the rules of a specific game and analyses those rules to construct for that game an efficient representation and an evaluation function, both for use with a generic search engine. The strategic analysis performed by the program relates a set of general knowledge sources to the details of the particular game. Among other properties, this analysis determines the relative value of the different pieces in a given game. Although \metagamer\ does not learn from experience, the values resulting from its analysis are qualitatively similar to values used by experts on known games, and are sufficient to produce competitive performance the first time the program actually plays each game it is given. This appears to be the first program to have derived useful piece values directly from analysis of the rules of different games.

Name:
kw10009/kw10009-thesis.dvi.gz kw10009/kw10009-thesis.ps.gz
Title:
Solving recursive domain equations with enriched categories
Author:
Kim.Wagner@cl.cam.ac.uk
Format:
gzip'ed DVI and Postscript
Details:
Carnegie Mellon University Ph.D. dissertation
Date:
11th August 1994 (replaces 6th June 1994)
We define a unifying framework for the partial order and the metric approach to solving recursive domain equations. This is done by parameterizing with respect to a notion of approximation. The notion of approximation in a pre-order is binary: either one element approximates another or it does not. For metric spaces the notion of approximation is classified by the non-negative real numbers. A point approximates another to the extent of its distance to that point. The well-know concept of enriched categories facilitates precisely this parameterization. Pre-orders are categories enriched over the two point lattice and (generalized) metric spaces are categories enriched over the non-negative real numbers, ordered as a lattice with 0 as top, signifying perfect approximation. In the framework of enriched categories we have defined a concept of convergence that unifies (eventual) chains in pre-orders with Cauchy sequences, and correspondingly a notion of limit that unifies (eventual) least upper bounds with metric limits. This makes it possible to define what we call colimsup complete enriched categories, unifying cpo's (not necessarily with a least element) and complete metric spaces, and further colimsup continuous maps, unifying the pre-order and the metric versions of continuous maps. Using these and other unifying concepts in the framework of enriched categories we have proven a general version of Scott's inverse limit theorem, and given sufficient conditions for when functors have fixed-points. We also discuss an internalization, carrying out the above constructions in sheaves over the base category.

Name:
ksj/ksj-whats-in-a-summary.ps.gz
Title:
What might be in a summary ?
Author:
Karen Sparck Jones <ksj@cl.cam.ac.uk>
Format:
gzip'ed Postscript
Date:
June 1993
Details:
From 'Information Retrieval 93: Von der Modellierung zur Anwendung' (ed Knorz, Krause and Womser-Hacker), Universitatsverlag Konstanz, 1993, 9-26
The paper presents a framework for, and strategies adopted in, an investigation of summarising designed to place future work on automatic summarising on solid foundations. The work reported has been focused on the role of large-scale text structure, and the paper describes comparative studies of different approaches to the characterisation of source text structure and to the use of this structure in summary formation.

Name:
ksj/ksj-towards-better-nlp-evaluation.dvi.gz
Title:
Towards Better NLP System Evaluation
Author:
Karen Sparck Jones <ksj@cl.cam.ac.uk>
Format:
gzip'ed dvi
Date:
March 1994
Details:
From 'Proceedings of the Human Language Technology Workshop, 1994}, (ARPA), San Francisco: Morgan Kaufmann, 1994, 102-107.'
This paper considers key elements of evaluation methodology, indicating the many points involved and advocating an unpacking approach in specifying an evaluation remit and design. Recognising the importance of both environment variables and system parameters leads to a grid organisation for tests. The paper illustrates the application of these notions through two examples.

Name:
as213/diss.dvi.gz
Title:
Algebras for Generalized Power Constructions
Author:
Andrea Schalk <as213@cl.cam.ac.uk>
Format:
gzip'ed dvi
Date:
July 1993
The question that we are concerned with here is whether the equational characterization of power constructions given by Hennessy and Plotkin for algebraic dcpo's remains valid if the setting is changed. We extract the equational description in the usual way, that is, by characterizing the associated (Eilenberg-Moore) algebras.

The three settings that we study are (arbitrary) dcpo's, topological spaces and locales. For all of them, power construction have been developed previously. We examine the algebras for two power constructions, modeling non-determinism as 'angelic' respectively 'demonic'. It turns out that in all cases the algebras can be understood as semilattices in the respective categories, sometimes satisfying additional properties.

Name:
as213/proc-main.ps.gz
Title:
A Fully Abstract Denotational Model for Observational Precongruence
Author:
Anna Ingolfsdottir and Andrea Schalk <as213@cl.cam.ac.uk>
Format:
gzip'ed PS
Date:
March 1996
A domain theoretic denotational model is given for a simple sublanguage of CCS extended with a divergence operator. The model is derived as an abstraction on a suitable notion of normal forms for labelled transition systems. It is shown to be fully abstract with respect to observational precongruence.