Knowledge ElicitationConcept Sorting

Knowledge Elicitation (Introduction)• Knowledge Elicitation is the process of acquiring knowledge about a

specific domain.

• It is one of the most important and a crucial task of the development of an expert system since it directly has an impact on the overall quality of the system.

• Knowledge elicitation is also often viewed as the bottleneck in the development of expert systems or knowledge based systems as it is difficult and time consuming activity.

• Among various known Knowledge Elicitation techniques available choice to be used depends on the nature of the situation within which the knowledge is elicited, the domain knowledge and availability of experts.

Knowledge Elicitation (Introduction) Cont…• Knowledge Elicitation process gets tricky as the vast amount of information

is often kept inside the heads of domain experts.• This makes the entire process complicated as the domain experts may not

be willing to disclose the information, due to worries of being sidelined or becoming less important or getting redundant.

• There are various techniques used in the Knowledge Elicitation process :• Interview• Protocol Analysis• Laddering• Concept Sorting (Will be discussing)• Repertory Grid• Structural Assessment

When to use which technique?

• For Knowledge identification• Unstructured interview, laddering

• For Knowledge specification• Domain schema: Concept Sorting, repertory grid

• Template selection: self report

• Task & inference knowledge: self report

• For Knowledge Refinement• Structured interview

What is Concept Sorting ?• Concept sorting is a psychological technique that is useful in tapping

organization knowledge.• It a way of finding out how an expert compares, orders concepts and relates

among a set of concepts.• Used to capture conceptual knowledge and tacit knowledge.• Can also sort objects or pictures instead of cards• It works best on small group.• Simple to apply• Its is also Called Card Sorting.• Simplest form is Concept Sorting

• Collection of concepts (or other knowledge objects) are written on separate cards • Cards sorted into piles by an expert in to piles - each card in a pile must have something

in common• Each time the cards are sorted it will be based on an attribute and each pile will

represent a value

Concept Sorting – How To ?

• To apply this technique , the KE follows the following steps:

1- First , KE Decide what classes of concepts he/she want to explore (in particular their properties – attributes and values).

2- Consults a textbook, training manual, or in-house domain expert to identify the major top-level concepts represented in the domain.

3- Place write the name of each concept on a separate note card .

4- Next, the KE asks the domain expert to begin sorting these cards placing them in groups according to those that belong together.

5- As the domain expert sorts the cards the KE uses questioning techniques to determine why they are placed together.

6- Repeat steps 4, and 5 until the expert can’t sort anymore

Example 1: Classification based of Habitat

Star Fish

Bear

Cat Shark

Deer

Seahorse

Crab

Crocodile

Frog

Elephant

Dolphin

Example 1: Classification based of Habitat Cont…

Dolphin

Aquatic Animalsns

Terrestrial Animal

Star Fish

Bear

Cat

Shark

Elephant

Deer

Seahorse

Crab

Crocodile

Frog

Amphibia

Card Habitat Size Eating Habit Vertebrate / InvertebrateMammals/

Non Mammals

Elephant 1 3 1 1 1

Cat 1 1 3 1 1

Deer 1 2 1 1 1

Bear 1 3 3 1 1

Crab 2 1 2 2 2

Crocodile 2 3 2 1 2

Frog 2 1 2 1 2

Dolphin 3 2 3 2 1

Starfish 3 1 3 2 2

Sea Horse 3 1 3 1 2

Shark 3 3 2 1 2

1-Teresstrial 1-Small 1-Herbivorous 1-Vertebrate 1-Mammals

2- Amphibia 2-Medium 2-Carnivorous 2-Invertebrate 2-Non-mammal

3-Aquatic 3-Large 3-Omnivorous

Example 2

• The Number of 15 models of cars may be grouped into two categories named “Foreign" and “Domestic

• Then re-sorted into three categories; “Sedan" , “Hatchback", and “Sports";

• Then re-sorted into four categories; " Expensive Domestic", " Less Expensive Domestic", " Expensive Foreign", “Less Expensive Foreign“.

• A hierarchy tree may be created expressing the group categories as levels within the hierarchy.

Based on Cost

Based on Design and Performance

Based on Design and Performance

Based on Cost

Example 2 Cont…

Domestic

Cars

Foreign

Less Expensive

Expensive SedanHatchback Sports

Less Expensive

Expensive SedanHatchback Sports

Application of Concept Sorting

• Concept sorting is basically used in several disciplines like

- Knowledge Engineering

- Psychology

- Marketing etc.

Pros and Cons

• Pros • Fast to apply and easy to analyze

• Often instructive to the expert in a sense that it may lead expert to see structure that he himself has not consciously articulated before

• Time saving by not having to transcribe and analyze lengthy verbal reports

• Can be used for images and objects as well

Pros and Cons Cont…

• Cons• Experts can often confound dimensions by not consistently applying the same

semantic distinctions throughout an elicitation session

• May face problem in categorization of elements in meaningful way

Conclusion

• Card Sorting techniques provide a means of achieving a more focused or systematic understanding of the classifications and relationships in the expert's domain.

Reference

http://liris.cnrs.fr/amille/enseignements/MasterCode/IC_IA/Session1_2008/commonkads/06-km-process.ppt

http://www.cse.aucegypt.edu/~rafea/csce485es/slides/ch.10.pdf

http://studentnet.cs.manchester.ac.uk/ugt/COMP34512/slides/day2.pdf

http://academic.cankaya.edu.tr/~agorur/AI/lect/knowledge.html