Knowledge Acquisition

1
Knowledge Acquisition

• Knowledge Acquisition
• The process of acquiring knowledge, from a human
  expert, or group of experts, and using this
  knowledge to build knowledge based systems

2
Knowledge Acquisition
inarticulate
argumentative
quickly bored
Delighted to talk to anyone and will exhaust any
knowledge engineer
3
Knowledge Acquisition

• Knowledge Acquisition Methods
• Computer tools
• Printed sources
• Interviews
• Unstructured
• Structured
• Event recall
• Questionnaires
• Formal techniques
• Observation techniques

4
Knowledge Acquisition

• Sources of Knowledge
• Procedure manuals
• Records of past case studies
• Standards documentation

5
Knowledge Acquisition

• The Interview
• An interview is a verbal and non verbal
  interaction between two parties, with the
  mutually agreed purpose of one party obtaining
  information from, or about, the other, in order
  that it may be used for a particular purpose

Discussion
Interview
Knowledge Engineer
Expert
6
Knowledge Acquisition

• Interview Methodology
• Successful interviewing requires -
• Planning
• Stage management techniques
• Social skills
• Self control

7
Knowledge Acquisition

• Interview Methodology
• Dont ask long, complicated or aggressive
  questions
• Ask one short, clear question and wait for an
  answer
• Speak the experts language
• Be aware of factors such as time, personality
  etc.
• Record the interview, - dont take notes

8
Knowledge Acquisition

• Interviews
• Approach the interview in an organised,
  structured and professional manner
• Advantages
• The knowledge engineer can satisfy both parties
  that the relevant points have been grasped
• Disadvantages
• Length of time to transcribe and analyse tapes
• Discrepancies between method described and method
  used

9
Knowledge Acquisition

• Unstructured Interviews
• The most widely used K.A. method
• Used mainly in the early stages
• Consist of free flowing dialogue
• Spontaneous questions
• Little prior planning
• Tend to take on a life of their own
• Will rarely provide a complete or well organised
  knowledge or process description

10
Knowledge Acquisition

• Structured Interviews
• Should be -
• Focused
• Relaxed
• Unhurried
• Interesting
• Informal

11
Knowledge Acquisition
agree sequence of topics
setting out goals
motivate the expert
Discuss agreed topics
Expert
Knowledge Engineer
Review the interview
12
Knowledge Acquisition

• Event Recall Interviews
• Actual cases are discussed
• Are good at revealing the actual decision making
  process
• Can be used to check completeness of earlier K.A.
  sessions
• Tend to degenerate into general discussion

13
Knowledge Acquisition

• Event Recall Interviews
• Questions may be asked such as -
• Could you talk me through that particular
  decision making process?
• What questions did you ask?
• In what order?
• Why did you ask those questions?

14
Knowledge Acquisition

• Forms
• Can be used to broadly itemise
  the aims of the session
• If given to the expert in advance
  of the session can be used as an
  agenda
• The forms can be completed during
  the interview and agreed by both
  parties

15
Knowledge Acquisition

• Tutorial Interview
• Aims to familiarise the knowledge engineer with
  the problem domain
• The expert is asked to prepare
  a short presentation on the
  subject under investigation

16
Knowledge Acquisition

• Twenty Questions
• An interview in which the expert can only answer
  yes or no
• Aims to gather the major characteristics or
  concepts of the domain
• Alternatively, the knowledge engineer can be
  supplied with a set of previously solved problems
  and the expert poses the questions to the K.E.

17
Knowledge Acquisition

• Trigger interviews
• The K.E. issues materials within the interview
  which are intended to trigger and stimulate the
  experts memories and responses
• May include structured structured diagrams
  derived from earlier KA sessions
• May also include archived data from past problem
  solving instances

18
Knowledge Acquisition

• Introspective Interviews
• (Sometimes called think aloud interviews)
• Involve asking the expert how they would solve a
  particular problem
• The expert is asked to verbalise their thought
  processes

19
Knowledge Acquisition

• Critical Instants
• The expert is asked to describe their experience
  with remarkable or difficult cases
• Can help to increase domain awareness

20
Knowledge Acquisition
Repertory grid
Elements
A list of people, objects or situations familiar
to the individual
Constructs
Elicited by means of a Repertory Test
Each element is rated by a scale
21
Knowledge Acquisition
Repertory grid for a Quality Control KBS
Elements
Adjustment to straighten sheet off-set
Scroll and cooling rails cleaned
Punch and dies changed
Scroll head position
Locators changed
Separator opened
Scroll timing
Cutter feed
Material
Constructs
Affect timing and feed before scroll
1
5
1
1
4
1
2
1
5
2
1
3
1
2
4
2
5
4
All of product
Bad rim before curler
1
5
5
4
1
1
5
4
3
Affects good or bad rim curler
1
3
1
3
1
4
1
3
1
2
3
5
1
3
2
2
1
4
Ragged trim at curler
22
Knowledge Acquisition
knowledge acquisition involving multiple experts
is fraught with the problems of dealing with
single experts compounded with obstacles and
risks of trying to co-ordinate human interactions
and integrate multiple knowledge bases
(La Salle and Medsker, 1991)
23
Knowledge Acquisition

• Knowledge Acquisition Tools
• The domain expert works directly with a
  computerised acquisition tool such as -
• Auinas...Elicits and models information using a
  knowledge acquisition workbench including
  repertory grid based interviewing
• Mole...Exploits information about how problems
  are solved to elicit diagnostic knowledge and
  uses feedback to fine tune knowledge
• Opal...Performs knowledge acquisition for the
  cancer treatment domain