E1AR0002@SMUVM1.BITNET (11/11/86)
TECHNICAL NOTE: 226\hfill PRICE: \$20.00\\[-0.15in]
\begin{tabbing}
\noindent TITLE: \= PROBLEMATIC FEATURES OF PROGRAMMING LANGUAGES:\\
\> SITUATIONAL-CALCULUS APPROACH\\
\> PART I: ASSIGNMENT STATEMENTS\\
AUTHORS: ZOHAR MANNA and RICHARD WALDINGER\\
DATE: NOVEMBER 1980\\[-0.15in]
\end{tabbing}
ABSTRACT: Certain features of programming languages, such as data
structure operations and procedure call mechanisms, have been found to
resist formalization by classical techniques. An alternate approach
is presented, based on a situational calculus,'' which makes explicit
reference to the states of a computation. For each state, a
distinction is drawn between an expression, its value, and the
location of the value.
Within this conceptual framework, the features of a programming
language can be described axiomatically. Programs in the language can
then be synthesized, executed, verified, or transformed by performing
deductions in this axiomatic system. Properties of entire classes of
programs, and of programming languages, can also be expressed and
proved in this way. The approach is amenable to machine
implementation.
In a situational-calculus formalism it is possible to model
precisely many problematic'' features of programming languages,
including operations on such data structures as arrays, pointers,
lists, and records, and such procedure call mechanisms as
call-by-reference, call-by-value, and call-by-name. No particular
obstacle is presented by aliasing between variables, by declarations,
or by recursive procedures.
The paper is divided into three parts, focusing respectively on
the assignment statement, on data structure operations, and on
procedure call mechanisms. In this first part, we introduce the
conceptual framework to be applied throughout and present the
axiomatic definition of the assignment statement. If suitable
restrictions on the programming language are imposed, the well-known
Hoare assignment axiom can then be proved as a theorem. However, our
definition can also describe the assignment statement of unrestricted
programming languages, for which the Hoare axiom does not hold.\\
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TECHNICAL NOTE: 227\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: AN APPROACH TO ACQUIRING AND APPLYING KNOWLEDGE\\
AUTHORS: NORMAN HAAS and GARY G. HENDRIX\\
DATE: NOVEMBER 1980\\[0.01in]
ABSTRACT: The problem addressed in this paper is how to enable a
computer system to acquire facts about new domains from tutors who are
experts in their respective fields, but who have little or no training
in computer science. The information to be acquired is that needed to
support question-answering activities. The basic acquisition approach
is learning by being told.'' We have been especially interested in
exploring the notion of simultaneously learning not only new concepts,
but also the linguistic constructions used to express those concepts.
As a research vehicle we have developed a system that is preprogrammed
with deductive algorithms and a fixed set of syntactic/semantic rules
covering a small subset of English. It has been endowed with
sufficient seen concepts and seed vocabulary to support effective
tutorial interaction. Furthermore, the system is capable of learning
new concepts and vocabulary, and can apply its acquired knowledge in a
range of problem-solving situations.\\
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TECHNICAL NOTE: 228\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: TRANSPORTABLE NATURAL-LANGUAGE INTERFACES TO DATABASES\\
AUTHORS: GARY G. HENDRIX and WILLIAM H. LEWIS\\
DATE: APRIL 1981\\[0.01in]
ABSTRACT: Several computer systems have now been constructed that
allow users to access databases by posing questions in natural
languages, such as English. When used in the restricted domains for
which they have been especially designed, these systems have achieved
reasonably high levels of performance. However, these systems require
the encoding of knowledge about the domain of application in complex
data structures that typically can be created for a new database only
with considerable effort on the part of a computer professional who
has had special training in computational linguistics and the use of
databases.
This paper describes initial work on a methodology for creating
natural-language processing capabilities for new databases without the
need for intervention by specially trained experts. The approach is
to acquire logical schemata and lexical information through simple
interactive dialogues with someone who is familiar with the form and
content of the database, but unfamiliar with the technology of
natural-language interfaces. A prototype system using this
methodology is described and an example transcript is presented.\\
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TECHNICAL NOTE: 229\hfill PRICE: \$10.00\\[-0.15in]
\begin{tabbing}
\noindent TITLE: \= THE INTERPLAY BETWEEN EXPERIMENTAL AND THEORETICAL\\
\> METHODS IN ARTIFICIAL INTELLIGENCE\\
AUTHOR: NILS J. NILSSON\\
DATE: SEPTEMBER 1980\\[-0.15in]
\end{tabbing}
ABSTRACT: This note alleges that there is a dichotomy between
theoretical and experimental work in Artificial Intelligence (AI).
The reasons for this dichotomy are discussed, and AI is compared with
other, more mature disciplines in which there is closer cooperation
between experimental and theoretical branches. Some recommendations
are given for achieving this needed cooperation.\\
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TECHNICAL NOTE: 230\hfill PRICE: \$10.00\\[-0.15in]
\begin{tabbing}
\noindent TITLE: \= KLAUS: A SYSTEM FOR MANAGING INFORMATION AND\\
\> COMPUTATIONAL RESOURCES\\
AUTHOR: GARY G. HENDRIX\\
DATE: OCTOBER 1980\\[-0.15in]
\end{tabbing}
ABSTRACT: This report presents a broad-brush description of the
basic goals and philosophy of a research program at SRI International
(SRI) aimed at developing the technology needed to support systems
that can be tutored in English about new subject areas, and that can
therefore aid the initial or subsequent user in filing and retrieving
information, and in conveniently applying to the new subject area
other computer software, such as data-base management systems (DBMS),
planners, schedulers, report generators, simulators and the like.
These systems, which we call Knowledge Learning and Using Systems
(KLAUS), are intended to act as brokers between the user's needs, as
expressed in the user's terms, and the resources available in a rich
computational environment.\\
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TECHNICAL NOTE: 232\hfill PRICE: \$14.00\\[-0.15in]
\begin{tabbing}
\noindent TITLE: \= A FIRST-ORDER FORMALIZATION OF KNOWLEDGE AND ACTION FOR A\\
\> MULTIAGENT PLANNING SYSTEM\\
AUTHOR: KURT KONOLIGE\\
DATE: DECEMBER 1980\\[-0.15in]
\end{tabbing}
ABSTRACT: We are interested in constructing a computer agent
whose behavior will be intelligent enough to perform cooperative tasks
involving other agents like itself. The construction of such agents
has been a major goal of artificial intelligence research. One of the
key tasks such an agent must perform is to form plans to carry out its
intentions in a complex world in which other planning agents also
exist. To construct such agents, it will be necessary to address a
number of issues that concern the interaction of knowledge, actions,
and planning. Briefly stated, an agent at planning time must take
into account what his future states of knowledge will be if he is to
form plans that he can execute; and if he must incorporate the plans
of other agents into his own, then he must also be able to reason
about the knowledge and plans of other agents in an appropriate way.
These ideas have been explored by several researchers, especially
McCarthy and Hayes [McCarthy and Hayes, 1969] and Moore [Moore 1980].
Despite the importance of this problem, there has not been a
great deal of work in the area of formalizing a solution. Formalisms
for both action and knowledge separately have been examined in some
depth, but there have been few attempts at a synthesis. The exception
to this is Moore's thesis on reasoning about knowledge and action
[Moore 1980], for which a planner has been recently proposed [Appelt
1980]. Moore shows how a formalism based on possible-world semantics
can be used to reason about the interaction of knowledge and action.
In this paper we develop an alternative formalism for reasoning about
knowledge, belief, and action; we show how this formalism can be used
to deal with several well-known problems, and then describe how it
could be used by a plan constructing systems.\\
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TECHNICAL NOTE: 233\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: COMPUTATIONAL STRUCTURES FOR MACHINE PERCEPTION\\
AUTHOR: MARTIN A. FISCHLER\\
DATE: JANUARY 1981\\[0.01in]
ABSTRACT: This note discusses the adequacy of current computer
architectures to serve as a base for building machine vision systems.
Arguments are presented to show that perceptual problems cannot be
completely formalized and dealt with in a closed abstract system. The
conclusion is that the digital computer, organized as a
general-purpose symbol processor, cannot serve as an adequate
instrument for achieving a human-like visual capability.\\
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TECHNICAL NOTE: 237\hfill PRICE: \$20.00\\[-0.15in]
\begin{tabbing}
\noindent TITLE: \= NATURAL-LANGUAGE PROCESSING\\
\> PART ONE: THE FIELD IN PERSPECTIVE\\
AUTHORS: GARY G. HENDRIX and EARL D. SACERDOTI\\
DATE: JULY 1981\\[-0.15in]
\end{tabbing}
ABSTRACT: This article deals with the problems of enabling
computers to communicate with humans in natural languages, such as
English and French, as distinguished from formal languages, such as
BASIC and PASCAL. Major issues in natural-language processing are
discussed by examining several experimental computer systems developed
over the last decade. The intent of the authors is to demonstrate
that natural-language processing techniques are useful now, to reveal
the richness of the computations performed by human natural-language
communicators, and to explain why the fluent use of natural language
by machines remains an elusive aspiration.\\
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TECHNICAL NOTE: 239\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: AUTOMATIC DEDUCTION FOR COMMONSENSE REASONING: AN OVERVIEW\\
AUTHOR: ROBERT C. MOORE\\
DATE: APRIL 1981\\[0.01in]
ABSTRACT: How to enable computers to draw conclusions
automatically from bodies of facts has long been recognized as a
central problem in artificial-intelligence (AI) research. Any attempt
to address this problem requires choosing an application (or type of
application), a representation for bodies of facts, and methods for
deriving conclusions. This article provides an overview of the issues
involved in drawing conclusions by means of deductive inference from
bodies of commonsense knowledge represented by logical formulas. We
first briefly review the history of this enterprise: its origins, its
fall into disfavor, and its recent revival. We show why applications
involving certain types of incomplete information resist solution by
other techniques, and how supplying domain-specific control
information seems to offer a solution to the difficulties that
previously led to disillusionment with automatic deduction. Finally,
we discuss the relationship of automatic deduction to the new field of
logic programming,'' and we survey some of the issues that arise in
extending automatic-deduction techniques to nonstandard logics.\\
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TECHNICAL NOTE: 240\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: NATURAL LANGUAGE ACCESS TO MEDICAL TEXT\\
AUTHORS: DONALD E. WALKER and JERRY R. HOBBS\\
DATE: MARCH 1981\\[0.01in]
ABSTRACT: This paper describes research on the development of a
methodology for representing the information in texts and of
procedures for relating the linguistic structure of a request to the
corresponding representations. The work is being done in the context
of a prototype system that will allow physicians and other health
professionals to access information in a computerized textbook of
hepatitis through natural language dialogues. The interpretation of
natural language queries is derived from DIAMOND/DIAGRAM, a
linguistically motivated, domain-independent natural language
interface developed at SRI. A text access component is being
developed that uses representations of the propositional content of
text passages and of the hierarchical structure of the text as a whole
to retrieve relevant information.\\
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TECHNICAL NOTE: 241\hfill PRICE: \$12.00\\[0.01in]
\noindent TITLE: PROBLEMS IN LOGICAL FORM\\
AUTHOR: ROBERT C. MOORE\\
DATE: APRIL 1981\\[0.01in]
ABSTRACT: Most current theories of natural-language processing
propose that the assimilation of an utterance involves producing an
expression or structure that in some sense represents the literal
meaning of the utterance. It is often maintained that understanding
what an utterance literally means consists in being able to recover
such a representation. In philosophy and linguistics this sort of
representation is usually said to display
the \underline{logical form} of an utterance.
This paper surveys some of the key problems that arise in
defining a system of representation for the logical forms of English
sentences and suggests possible approaches to their solution. We
first look at some general issues relating to the notion of logical
form, explaining why it makes sense to define such a notion only for
sentences in context, not in isolation, and we discuss the
relationship between research on logical form and work on knowledge
representation in artificial intelligence. The rest of the paper is
devoted to examining specific problems in logical form. These include
the following: quantifiers; events, actions and processes; time and
space; collective entities and substances; propositional attitudes and
modalities; questions and imperatives.\\
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TECHNICAL NOTE: 243\hfill PRICE: \$20.00\\[0.01in]
\noindent TITLE: KNOWLEDGE-ENGINEERING TECHNIQUES AND TOOLS\\
AUTHOR: RENE REBOH\\
DATE: MAY 1981\\[0.01in]
ABSTRACT: Techniques and tools to assist in several phases of the
knowledge-engineering process for developing an expert system are
explored.
A sophisticated domain-independent network editor is described
that uses knowledge about the representational and computational
formalisms of the host consultation system to watch over the
knowledge-engineering process and to give the knowledge engineer a
convenient environment for developing, debugging, and maintaining the
knowledge base.
We also illustrate how partial matching techniques can assist in
maintaining the consistency of the knowledge base (in form and
content) as it grows, and can support a variety of features that will
enhance the interaction between the system and the user and make a
knowledge-based consultation system behave more intelligently.
Although these techniques and features are illustrated in terms
of the Prospector environment, it will be clear to the reader how
these techniques can be applied in other environments.\\
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TECHNICAL NOTE: 244\hfill PRICE: \$10.00\\[0.01in]
\noindent TITLE: DETECTION OF RIVERS IN LOW-RESOLUTION AERIAL IMAGERY\\
AUTHOR: GRAHAME B. SMITH\\
DATE: JUNE 1981\\[0.01in]
ABSTRACT: This paper describes an operator for detecting rivers
in low-resolution aerial imagery. The operator provides results that
would allow graph-traversing routines to delineate these structures.
The approach is to look for the typical river profile involving not
only the water component of the river, but its surrounding vegetation
as well.\\
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TECHNICAL NOTE: 245\hfill PRICE: \$12.00\\[0.01in]
\noindent TITLE: AN INTERACTIVE PLANNING SYSTEM\\
AUTHORS: ANN ROBINSON and DAVID WILKINS\\
DATE: JUNE 1981\\[0.01in]
ABSTRACT: A principal goal of our planning and plan execution
research is to develop a computer system that interacts with a person
planning some activity. The system, designed to be independent of the
problem area in which the planning takes place, will allow the person
to (1) represent the problem area and the actions that may be
performed in it; (2) explore alternative plans for performing the
activity; (3) monitor the execution of a plan so produced; and (4)
modify the plan as needed during its execution. The system currently
being tested allows a person to produce a plan inter- actively,
suggesting alternative actions, showing the effects of actions on the
situation, checking for problems in the plan, and (occasionally)
suggesting corrections for such problems. The plan is represented as
a hierarchy of actions linked together in a network, generally called
a procedural network.''
Current areas of investigation include the following: (1)
development of representations for encoding information about a given
problem area, stressing the representation of actions that may be
performed in it; (2) development of computational methods for
identifying difficulties in a plan, such as the overallocation of a
resource or the possible effect of one action on the successful
performance of subsequent actions; (3) development of strategies for
deciding which actions and action sequences should be included in a
plan; (4) development of effective communication with the user,
including determining which and how much information should be
communicated, and how best to present it.\\
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