early work masterman: 100 primitive concepts, 15,000 concepts wilks: natural language system using...
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Early Work
Masterman: 100 primitive concepts, 15,000
conceptsWilks: Natural Language system using semantic
networksShapiro: Propositional calculus based semantic
network
Quillian's network
Nodes correspond to word concepts with links to
other concepts used to define it.Organized into planes, each plane a graph that
defines a single meaning of a word.Links are associative and named, and may be multi-
arcs (ors)Use to find relationships between pairs of words
through graph search.
Schank's Conceptual Dependency
Four primitive conceptualizations: ACT (actions),
PP (objects – picture producers), AA (action
modifiers or aiders), PA (picture modifiers or
aiders)Fixed set of primitive actions: ATRANS, PTRANS,
PROPEL, MOVE, GRASP, INGEST, EXPEL,
INGEST, MTRANS, MBUILD, CONC, SPEAK,
ATTEND.
Schank (cont'd)
Different kind of links (multi-arcs): actor (agent),
attribute, object, recipient, donor, direction,
instrumental conceptualization, causality, state of
change, possessor, partClaim is that all knowledge can be broken down
into this primitive concepts.Used to create canonical forms of natural language
expressions.
Simmon's Case Based Represent.
Based on Filmore's case structure of verbs.Verbs are the main nodesHave actor, object, instrument, location, and timeCaptures deep structure of sentence
Scripts (Schank and Abelson)
Used to incorporate real-world, common-sense
default knowledge and to organize large amounts of
information.Incorporates expected actions and elements. The
actual situation may differ.Scripts have the following components: Entry
conditions, Results, Props, Roles, and Scenes.Each element is represented by conceptual dep.
Easy Example
Amy went out to lunch. She sat at a table and called a
waitress, who brought her a menu. She ordered a
sandwich.
Hard Example
John visited his favorite restaurant on the way to the
concert. he was pleased by the bill because he liked
Mozart.
Frames (Minsky)
Frames are structured entities with named slots and
attached values. Values may be procedural (think
objects).Frames are related to one another.Example slots: ID, relationship to other frames,
description of requirements, procedural
information, default information, new instance
information.Frames support class inheritance.
Conceptual Graphs (Sowa)
Two types of nodes: concepts and conceptual
relations.Arcs are not labeled – a conceptual relation node
appears between two concept nodes instead.Concept nodes may be concrete or abstract objects.Each graph represents a single proposition.A graph may be boxed and used as a node in
another graph.
Conceptual Graphs (cont'd)
Every concept is of a unique individual of a give
type.Each concept box is labeled with a type label. (:)A concept could be a specific, but unnamed
individual. (#)A name is different from the object (name
conceptual relation)A concept may be an unspecified individual (*).There is a type hierarchy.
Conceptual Graphs: Rules
The following rules may be used to modify graphs:An exact copy may be made (copy rule).A generic marker may be replaced by an individual
marker (restrict).A type may be replaced by a subtype as long as the
subtype is consistent with the referent (restrict).Two graphs may be joined by a common concept
(join).
Propositional Concepts
Graphs may be used to represent relations between
propositions (causality, time, etc.) A propositional
concept is indicated by a box around a conceptual
graph and may be used as a node in another graph.
Neg and conjunction are conceptual relations.
Conceptual graphs have the same expressive power
as the predicate calculus.
Subsumption Architecture (Brooks)
The idea is that intelligence emerges from the
interaction of architectures of simpler behaviors.Layered collection of task-handlers which interact
with neighboring layers.Each task-handler perceives (input from a lower
level), applies a simple set of condition-action
production rules, and produces action-orient output
(to a higher level).
Brooks (cont'd)
No global state.Some feedback to lower levels.Example: Machine robot: Three levels – Explore,
Wander, Avoid.