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Relational knowledge is made up of objects
- corresponding associated values.
We extend the base more by allowing inference mechanisms:
- Property inheritance
- elements inherit values from being members of a
- data must be organised into
a hierarchy of classes (Fig. 8).
Fig. 8 Property Inheritance Hierarchy
- Boxed nodes -- objects and values of attributes of objects.
- Values can be objects with attributes and so on.
- Arrows -- point from object to its value.
- This structure is known
as a slot and filler structure, semantic network or a collection of frames.
The algorithm to retrieve a
value for an attribute of an instance object:
- Find the object in the knowledge
- If there is a value for the attribute report it
- Otherwise look for a
value of instance if none fail
- Otherwise go to that node and find a value for the
attribute and then report it
- Otherwise search through using isa until a value
is found for the attribute.