The University of Georgia

                                            

Artificial Intelligence

Research Reports and Software


Artificial Intelligence Programs

Graduate Studies Research Center, Room 111 

Athens, Georgia 30602

aspaul@uga.cc.uga.edu


Last revised 1991 November 4 




RESEARCH REPORTS


IMPORTANT NOTICE: Due to demand, we have had to institute a charge of $3 

each ($5 outside the U.S.A.) for printed reports. Make checks payable to 

AI Program Development Fund and be sure to give your full mailing 

address when ordering. See order form at end.


Many reports are also available in electronic form. To get information 

on reports available through the Internet, do the following:


unix%  ftp aisun1.ai.uga.edu     (or ftp 128.192.12.9)

User name: anonymous

Password:  (type your email address here)   

ftp> cd ai.reports

ftp> get Contents

ftp> quit


This will transmit a file named `Contents' to your computer. Procedures 

will vary slightly depending on how your computer is configured. Consult 

your local computer center for help.



REPORTS AVAILABLE:



AI-1991-02 (available by FTP)

Donald Nute

Tense and Conditionals


Temporal relations play an essential role in determining the truth 

values of many conditional assertions.  This paper explores the 

possibilities for developing a formal language containing both tense and 

conditional operators, and a model theory for such a language.



AI-1991-01

Gregg H. Rosenberg

SALMON: a TEMPERAMENTAL Program that Learns


This thesis introduces a new approach to machine learning that combines 

aspects of semantic and connectionist systems. A sample program learns 

to play a children's game of tag.



AI-1990-02 (available by FTP)

William H. Smith

Handling Constrained Clauses in Discourse Representation Theory


This report describes a Prolog program that transforms a natural 

language input into a knowledge base of Prolog clauses. The key element 

of the program is its ability to handle constrained clauses, i.e., 

embedded clauses whose truth evaluation is affected by the matrix 

clause, such as `Carol kissed Ted' in `Bob believes Carol kissed Ted'.



AI-1990-01 (available by FTP)

Michael A. Covington

A Dependency Parser for Variable-Word-Order Languages


Most human languages allow considerably more variation of word order 

than does English. This paper presents a parsing algorithm for 

variable-word-order languages based on dependency grammar. Unlike 

earlier dependency parsers, this one does not require constituents to be 

continuous, but merely prefers them so. A Russian parser using this 

algorithm has been implemented on an IBM 3090 and this paper includes an 

evaluation of the suitability of the IBM 3090 architecture for natural 

language processing. 



AI-1989-09   

David Billington

Some Results on Defeasible Logic


Defeasible Logic is defined and the intuition behind the definition is 

explained. Some new results are then proved which confirm and sharpen 

our intuition.



AI-1989-08 (available by FTP)

Michael A. Covington

Efficient Prolog: A Practical Guide


Properly used, Prolog is as fast as any language with comparable power. 

This paper presents guidelines for using Prolog efficiently. Some of 

these guidelines rely on implementation- dependent features such as 

indexing and tail recursion optimization; others are matters of pure 

algorithmic complexity.



AI-1989-07   

John E. McEneaney

Implementing Set Theory in Prolog


This paper describes an implementation of set theory in Prolog that 

avoids certain problems characteristic of the standard approach 

(Bharath, 1986; Clocksin and Mellish, 1987). Two of the four basic 

set-theoretic predicates in the standard approach, subset and 

intersection, are shown to result in errors. The alternatives proposed 

in this paper remedy these problems. The major distinguishing feature of 

the implementation proposed here is the implementation of an 

equivalent_sets predicate that defines list equivalence solely on the 

basis of the elements in lists, regardless of their order.



AI-1989-06   

W. D. Potter, A. D. Wright, A. M. Morton, and V. C. Kessler

Handling Uncertainty and Exceptions with Defeasible Dependencies


Recently, the merger of artificial intelligence techniques with database 

management concepts has sparked much interest. One important area is the 

development of a theory for relational database design based on 

absolute, incomplete, and uncertain knowledge about the domain. The 

approach presented here brings a new dimension to the traditional theory 

of relational database design based solely on absolute knowledge. 

Specifically, we present the foundations of a theory of defeasible 

dependencies, which are closely related to functional dependencies but 

allow exceptions as well as uncertain relationships between groups of 

attributes to be represented.



AI-1989-05   

David Billington, Koen De Coster, Donald Nute

A Modular Translation from Defeasible Nets to Defeasible Logics


Recent work in nonmonotonic logic investigates relationships between 

different defeasible reasoning formalisms. Of particular interest are 

inheritance reasoners with multiple inheritance and exceptions. We show 

that the Skeptical Inheritance Reasoner of Horty, Thomason, and 

Touretzky is equivalent to a special case of Nute's general defeasible 

logic.



AI-1989-04 (available by FTP)

William H. Smith

Problems in Applying Discourse Representation Theory


This report describes discourse representation theory, both the 

original, basic form and some extensions that have been suggested by 

Kamp and others, and applies it to a "real" discourse in order to 

indicate further extensions that will be necessary if DRT is to be used 

as a complete theory of semantic representations.



AI-1989-03   

David Goodman

An Implementation of an Extension to Discourse Representation Theory


This report presents a declaratively formulated model of 

intra-sentential and inter-sentential anaphoric dependencies for a 

fragment of the English language with syntactic and semantic structures 

built from a single rule formalism. The model is based on, and contains 

extensions to, Discourse Representation Theory (Kamp 1981, 1983, 1985). 

Input strings are converted to discourse representation structures and 

then to Prolog clauses.



AI-1989-02 (available by FTP)

Michael A. Covington

A Numerical Equation Solver in Prolog


The Prolog inference engine can be extended to solve for unknowns in 

arithmetic equations such as X-1=1/X or X=cos(X), whether or not the 

equations have analytic solutions. This is done by standard numerical 

methods, but two features of Prolog make the implementation easy: the 

ability to treat expressions as data and the ability of the program to 

extend itself at run time. (Published in Computer Language, Oct. 1989, 

45-51.)



AI-1989-01 (available by FTP)

Michael A. Covington

GULP 2.0: An Extension of Prolog for Unification-Based Grammar


A simple extension to Prolog facilitates implementation of 

unification-based grammars by adding a new notational device, the 

feature structure, whose behavior emulates graph unification. For 

example, a:b..c:d represents a feature structure in which a has the 

value b, c has the value d, and all other features (if any) are 

undefined. The extended language is known as GULP (Graph Unification 

Logic Programming); it is as powerful and concise as PATR-II and other 

grammar development tools, while retaining all the versatility of 

Prolog.



01-0027 (available by FTP)

Tsanming J. Chou

A Comparative Performance Study on Various Parsers Written in Prolog


01-0026      

Martin Volk

Parsing German with GPSG: The Problem of Separable-Prefix Verbs


01-0025      

John E. McEneaney

READ.PRO: A Pattern-Matching Approach to Perceptual Learning in Reading 


01-0024 (available by FTP)

M. Covington, D. Nute, N. Schmitz, and D. Goodman

From English to Prolog via Discourse Representation Theory


01-0023 (available by FTP)

Michael A. Covington and Nora Schmitz

An Implementation of Discourse Representation Theory


01-0022

Michael A. Covington 

Parsing Variable Word Order Languages With Unification-Based Dependency 

Grammar

No longer available -- Use report AI-1990-01 instead.


01-0021

Michael A. Covington

GULP 1.1:  An Extension of Prolog for Unification-Based Grammar

No longer available -- Use report AI-1989-01 instead.


01-0020      

S. Karickhoff, A. Vellino, L. Carreira, V. McDaniel, and D. Nute

Predicting Chemical Parameters with Prolog


01-0019      

Robert E. Stearns and Michael A. Covington

Prolog on the CYBERPLUS: A Feasibility Study


01-0018      

Andre N. Vellino

Searching Chemical Substructures Using Prolog


01-0017

Donald Nute and Michael Lewis

A User's Manual for d-Prolog


01-0016

Michael Lewis

Defeasible Reasoning in the Expert System Shell TOPSI


01-0015

Donald Nute and Michael Covington

Implicature, Disjunction, and Non-monotonic Logic


01-0014

Michael Lewis

The Automation of a Practical Reasoning System Based on Concepts in Deontic Logic


01-0013

Donald Nute

LDR: A Logic for Defeasible Reasoning

No longer available -- See D. Nute, "Defeasible Reasoning and Decision

       Support Systems," Decision Support Systems 4 (1988) 97-110.


01-0012

Michael A. Covington

Expressing Procedural Algorithms in Prolog

No longer available -- see PC Tech Journal, March 1987, or Chapter 4 of

       Covington, Nute, and Vellino, Prolog Programming in Depth.


01-0009

Terry L. Rankin 

Could Nonmonotonic Inference Ever Be Deductively Valid?


01-0007

Donald Nute

A Non-Monotonic Logic Based on Conditional Logic


01-0003

Terry L. Rankin 

AI Artifacts and Applied Epistemology


01-0002

Donald Nute

Non-Monotonic Reasoning and Conditionals



SOFTWARE


A large archive of software is available by anonymous FTP from 

aisun1.ai.uga.edu (128.192.12.9).


For those who cannot use FTP, the following software is available on IBM 

PC 3.5" or 5.25" diskettes at $15 per diskette, which covers duplication 

and mailing only. Please make checks payable to AI Program Development 

Fund. Software is experimental and is provided "as is," without any 

warranty or promise of user support. Do not order multiple copies of a 

disk -- instead, order one copy, then duplicate it yourself.


Disk 1              

d-Prolog source code


This is the source code for d-Prolog as described in Research Report 

01-0017 above. You must have a Prolog compiler or interpreter in order 

to run it. As supplied, it runs under Arity Prolog, and it runs with at 

most minor modifications under ALS Prolog, Quintus Prolog, and other 

Edinburgh-compatible implementations (but not Turbo Prolog). (Be sure to 

request Report 01-0017 for documentation.)



Disk 2              

Prolog Programming Examples


Source code for the example programs in Covington, Nute, and Vellino, 

Prolog Programming in Depth. Available in 3 versions: in Arity Prolog 

(as published in the book), or modified for ALS or Quintus Prolog. The 

Arity version is supplied if you do not state a preference.



Disk 3              

GULP source code


Source code for GULP, the unification-based grammar development tool 

described in Research Report AI-1989-01. Two versions are provided on 

one disk: Arity Prolog and Quintus Prolog.



Disk 4              

Editors and utilities


A collection of utility programs for the IBM PC, including two 

WordStar-like full-screen editors, AHED and PrEd. Users are welcome to 

copy and distribute these editors to anyone free of charge. They feature 

pop-up help menus and are especially suitable for use in programming 

classes. Memory requirements are very small and both editors are 

suitable for running as a subprocess under a Prolog interpreter or 

compiler.



ORDER FORM


Make checks payable to:           AI Program Development Fund


Send orders to:                   Artificial Intelligence Programs

                                  The University of Georgia

                                  Athens, GA 30602 U.S.A.



Reports ($3 each, $5 outside the U.S.A.):


[] AI-1991-02 Nute

[] AI-1991-01 Rosenberg

[] AI-1990-02 Smith

[] AI-1990-01 Covington

[] AI-1989-09 Billington

[] AI-1989-08 Covington

[] AI-1989-07 McEneaney

[] AI-1989-06 Potter

[] AI-1989-05 Billington

[] AI-1989-04 Smith

[] AI-1989-03 Goodman


[] AI-1989-02 Covington

[] AI-1989-01 Covington

[] 01-0027 Chou

[] 01-0026 Volk

[] 01-0025 McEneaney

[] 01-0024 Covington

[] 01-0023 Covington

[] 01-0022 Covington

[] 01-0020 Karickhoff

[] 01-0019 Stearns

[] 01-0018 Vellino


[] 01-0017 Nute

[] 01-0016 Lewis

[] 01-0015 Nute

[] 01-0014 Lewis

[] 01-0009 Rankin

[] 01-0007 Nute

[] 01-0003 Rankin

[] 01-0002 Nute


Disks ($15 each)


[] 1. d-Prolog source code

[] 2a. Prolog programming examples - Arity Prolog

[] 2b. Prolog programming examples - ALS Prolog

[] 2c. Prolog programming examples - Quintus Prolog

[] 3. GULP source code

[] 4. Editors and utilities


Your mailing address:             ___________________________________


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Total enclosed (U.S. funds only): ______________

