Chapter 4, 7 12

Knowledge Representation

Chapter 4 : Symbolic Computation

LISP: List Processing

Rather than just manipulating numbers, computers can now manipulate symbols.

Typically a symbolic program takes as its input one or more symbol structures, representing the initial state of some problem, and returns as its output a symbol structure.

syntactic rules
transformation rules

Programs in such languages are themselves symbol structures - thus some programs can treat other programs as data

Physical Symbol Systems (Newell and Simon, 1976)

"A physical symbol system has the necessary and sufficient means for intelligent action."

Some characteristics of LISP

Main data structure is a list
Programs represented by list structures
Primitive operations are operations on lists

Functional language

atoms

s-expressions (symbolic expressions)

a-lists (association lists) (consider: early IV&CV)

Program *a lot* with a very small core

simplicity
metaprogrammability (Jackson: page 131)

Levels of analysis -- Newell and Knowledge Level

knowledge level what (functional)

symbol level (program) how (structural (and processes))

computer systems how (hardware)

Chapter 7 : Object-Oriented Programming

KRL (Knowledge Representation Language) (Bobrow, 1977) (Jackson, page 173)

KEE (Knowledge Engineering Environment)

FLAVORS

LOOPS

CLOS

Java ??

knowledge level	what	(functional)
symbol level (program)	how	(structural (and processes))
computer systems	how	(hardware)