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AIList Digest Volume 4 Issue 174
AIList Digest Friday, 1 Aug 1986 Volume 4 : Issue 174
Today's Topics:
Seminars - Specification of Geographic Data Processing Requirements (UPenn) &
Constructing the Aspect Graph (GMR) &
RS: Distributed Sensory-based Robot Control (UMass) &
Decision-Making and Action in the Real World (SRI)
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Date: Thu, 24 Jul 86 15:05 EDT
From: Tim Finin <Tim@cis.upenn.edu>
Subject: Seminar - Specification of Geographic Data Processing
Requirements (UPenn)
Forwarded From: Glenda Kent <Glenda@upenn> on Thu 24 Jul 1986 at 14:40
FORMAL SPECIFICATION OF GEOGRAPHIC DATA PROCESSING REQUIREMENTS
Gruia-Catalin Roman
Department of Computer Science
Washington University
This presentation discusses a formal foundation for the specification of
Geographic Data Processing (GDP) requirements. The emphasis is placed on
modelling data and knowledge requirements rather than processing needs. A
subset of first order logic is proposed as the principal means for constructing
formalizations of the GDP requirements in a manner that is independent of the
data representation. Requirements executability is achieved by selecting a
subset of logic compatible with the inference mechanisms available in Prolog.
GDP significant concepts such as time, space and accuracy have been added to
the formalization without losing concepts such as time, space and accuracy have
been added to the formalization without losing Prolog implementability or
separation of concerns. Rules of reasoning about time, space and accuracy
(based on positional, temporal and fuzzy logic) may be compactly stated in a
subset of second order predicate calculus and may be easily modified to meet
the particular needs of a specific application. Multiple views of the data and
knowledge may coexist in the same formalization. The feasibility of the
approach has been established with the aid of a tentative Prolog implementation
of the formalism. The implementation also provides the means for graphical
rendering of logical information on a high resolution color display.
Acknowledgements: This work was supported in part by Defense Mapping Agency
and by Rome Air Development Center under contract F30602-83-K-0065. The full
text of this presentation is available in "Formal Specification of Geographic
Data Processing Requirements," Proceedings of the 2nd International Conference
on Data Engineering, (Outstanding Paper Award), pp. 434-446, February 1986.
------------------------------
Date: Mon, 28 Jul 86 22:18 EST
From: "Steven W. Holland" <HOLLAND%RCSMPA%gmr.com@CSNET-RELAY.ARPA>
Subject: Seminar - Constructing the Aspect Graph (GMR)
Seminar at General Motors Research Laboratories (GMR):
An Algorithm for Constructing the Aspect Graph
Dr. Charles R. Dyer
of
Computer Science Department
University of Wisconsin
Madison, WI 53706
Thursday, August 14, 1986
The aspect graph of a solid object is a representation of the visibility
of the object's surfaces throughout surrounding viewing space. In this
talk we present tight bounds on the maximum size of aspect graphs and
give worst-case optimal algorithms for their construction, first in the
convex case and then in the general case. The algorithm for the general
case makes use of a new 3-D object representation called the aspect
representation or "asp". We also suggest several alternatives to the
aspect graph which require less space and store more information.
-Steve Holland, Computer Science Department
------------------------------
Date: Sun, 27 Jul 86 16:11 EST
From: Damian Lyons <LYONS%cs.umass.edu@CSNET-RELAY.ARPA>
Subject: Seminar - RS: Distributed Sensory-based Robot Control (UMass)
Hi: I know I'm a bit late on posting this; however, I would welcome
comments from interested persons out there:
July 25th, 1986.
Dept. of Computer and Information Science.
University of Massachusetts at Amherst.
Amherst, MA.01003.
RS: A Formal Model of Distributed Computation
For Sensory-based Robot Control.
Damian M. Lyons
Robot systems are becoming more and more complex, both in terms of
available degrees of freedom and in terms of sensors. It is no longer
possible to continue to regard robots as peripheral devices of a computer
system, and to program them by adapting general-purpose programming
languages. This dissertation analyzes the inherent
computing characteristics of the robot programming domain, and formally
constructs an appropriate model of computation. The programming of a dextrous
robot hand is the example domain for the development of the model.
This model, called RS, is a model of distributed computation: the basic
mode of computation is the interaction of concurrent computing agents. A
schema in RS describes a class of computing agents. Schemas are instantiated
to produce computing agents, called SIs, which can communicate with each
other via input and output ports. A network of SIs can be grouped atomically
together in an Assemblage, and appears externally identical to a single SI.
The sensory and motor interface to RS is a set of primitive, predefined
schemas. These can be grouped arbitrarily with built-in knowledge in
assemblages to form task-specific object models. A special kind of
assemblage called a task-unit is used to structure the way robot programs
are built.
The formal semantics of RS is automata theoretic; the semantics of an
SI is a mathematical object, a Port Automaton. Communication, port
connections, and assemblage formation are among the RS concepts whose
semantics can be expressed formally and precisely. A Temporal Logic
specification and verification methodology is constructed using the automata
semantics as a model. While the automata semantics allows the analysis of
the model of computation, the Temporal Logic methodology allows the top-down
synthesis of programs in the model.
A computer implementation of the RS model has been constructed, and used
in conjunction with a graphic robot simulation, to formulate and test
dextrous hand control programs. In general RS facilitates the formulation
and verification of versatile robot programs, and is an ideal tool with
which to introduce AI constructs to the robot domain.
------------------------------
Date: Wed 30 Jul 86 17:43:10-PDT
From: Amy Lansky <LANSKY@SRI-WARBUCKS.ARPA>
Subject: Seminar - Decision-Making and Action in the Real World (SRI)
DECISION-MAKING AND ACTION IN THE REAL WORLD
John Myers (JMYERS@SRI-AI)
SRI International, Robotics Laboratory
11:00 AM, MONDAY, Aug. 4
SRI International, Building E, Room EK228
In this philosophical talk I will present my opinions as to how to
design an entity capable of operating in the real world, under limited
resources. These include limited time, information, and capabilities.
I will present models that stress heuristic aspects of behavior,
rather than traditional pre-planning techniques. As Terry Winograd has
said, "The main problem is to come up with what you are going to do in
the next five seconds."
After covering the problem and some traditional paradigms, I will
discuss three main concepts, along with a follow-up concept. These
are: the Theory of Stances, the Freudian Motivation Model, and the
Theory of Alternative Choices, along with the Principle of
Responsibility. These are contrasted against traditional approaches
by their emphasis on workability, as opposed to correctness.
A Stance consists of a high-level classification of a situation, along
with a high-level precompiled response script. Often there is
insufficient information in a prima facia situation to correctly
determine what is going on; or, the entity may simply not be able to
afford the overhead required to completely plan its behavior from
first principles. Taking a stance on the situation allows a habitual
response to be made; which at least is some action in the face of the
unknown, and at best, solves the problem with minimal effort.
The Freudian Motivation Model splits behavior generation into three
general processes: generation, policies, and judgment, corresponding
to the id, superego, and ego, respectively. Approved behaviors are
put on an intention queue or a performance queue, among others. The
model can be used to explain nonpurposeful or nonvolitional behaviors
such as posthypnotic acts or compulsions.
The Theory of Alternative Choices says that given a direct choice
between, for example, one of two actions, there are actually a number
of alternative decisions that must be considered. These include: do
nothing, wait, waffle, observe/consult, relegate, delegate, react,
transcend, or respond with a stance. One of these may be much more
appropriate in a resource-limited situation than directly planning out
a decision between the two original choices.
As a follow-up, the Principle of Responsibility says that the entity
(the computer) must be responsible for its actions and its
recommendations. In a certain sense, it must be willing to be wrong.
Even if it is totally convinced of the correctness of its situational
assessment, it must consider the possibility that things might go
badly, given a certain course of action--and it must use that as
further input to the decision process.
Examples will be interspersed in the talk.
VISITORS: Please arrive 5 minutes early so that you can be escorted up
from the E-building receptionist's desk. Thanks!
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End of AIList Digest
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