Here is one way we can think about knowledge that makes it different
from information or data:
p.491"Knowledge is very distinct from data and information in the
information technology context... Whereas data are a collection of facts, measurements, and statistics, information is organized
or processed data that are timely (i.e., inferences from the data are drawn within the time frame of applicability) and accurate
(i.e., with regard to the original data)... Knowledge is information that is contextual, relevant, and actionable... Having
knowledge implies that it can be exercised to solve a problem, whereas having information does not carry the same connotation.
An ability to act is an integral part of being knowledgeable... knowledge provides a higher level of meaning about
data and information. It conveys meaning"
Heuristics seem to be a form of condensed experience - the condensing makes them usable, but at
the same time it also makes them potentially (but hopefully rarely) inaccurate.
p.542"Heuristics consists of intuitive knowledge, or rules of thumb,
learned from experience. Its role in AI is seen in the following definition: Artificial intelligence is the branch of computer
science that deals with ways of representing knowledge using symbols with rule-of-thumb, or heuristic, methods for processing
information (Encyclopaedia Britannica)."
We can use heuristics to build higher-level knowledge from facts and rules - this is inferencing.
p.542"Inferencing [section title] As an alternative to heuristics, artificial intelligence also
builds reasoning capabilities that can build higher-level knowledge from existing heuristics. This reasoning consists of inferencing
from facts and rules using heuristics or other search approaches."
If we wish our computer chess program to mimic a human expert, here is what we can look forward
to obtain from it:
p.549"Typically, human experts are capable of doing the following:
- Recognizing and formulating the problem
- Solving the problem quickly and correctly
- Explaining the solution
- Learning from experience
- Restructuring knowledge
- Breaking rules if necessary
- Determining relevance
- Degrading gracefully (being aware of one's limitations)."
A knowledge base is an important component of an expert system:
p.556"The knowledge base contains the relevant knowledge necessary for understanding, formulating,
and solving problems. It includes two basic elements: (1) facts, such as the problem situation and the theory of the problem
area, and (2) special heuristics or rules that direct the use of knowledge to solve specific problems in a particular domain.
(In addition, the inference engine can include general purpose problem-solving and decision-making rules.) The heuristics
express the informal judgmental knowledge in an application area. Knowledge, not mere facts, is the primary raw material of
expert systems."
The inference engine performs the equivalent of thinking
as the knowledge is transformed into a solution through the act of reasoning.
p.566"The 'brain' of the ES [expert system] is the inference engine,
also known as the control structure or the rule interpreter (in rule-based ES). This component is essentially a computer program
that provides a methodology for reasoning about information in the knowledge base and on the blackboard, and for formulating
conclusions. This component provides directions about how to use the system's knowledge by developing the agenda that
organizes and controls the steps taken to solve problems whenever consultation takes place."
The plan, agenda and solution are all features that we are likely
to find on the blackboard, or working memory of an expert system.
p.556"The blackboard is an area of working memory set aside as a database for the description
of a current problem as specified by the input data; it is also used for recording intermediate hypotheses and decisions.
Three types of decisions can be recorded on the blackboard: a plan (how to attack the problem), an agenda (potential actions
awaiting execution), and a solution (candidate hypotheses and alternate courses of action that the system has generated thus
far."
