Structured KR Flashcards
(32 cards)
What is the focus of Associationist Theories of Meaning?
Defining meaning through network associations among objects.
Why are structured representations used in KR?
They capture semantics better and support cognitive economy through inheritance.
What is a representational network?
A subset of NxLxN where nodes are connected via labeled links; order of triples matters.
What is a directed graph in KR?
A graph where the order of node pairs in NxN matters.
What are nodes and arcs in a semantic network?
Nodes are concepts, arcs are labeled relationships.
What is the ‘isa’ link?
Shows class inheritance without adding new properties.
What is the ‘ako’ link?
Shows subclass relation where properties may be added.
What is the ‘instance_of’ link?
Links an object to the class it belongs to.
How does inheritance work in semantic nets?
Nodes inherit attributes from nodes higher in the hierarchy.
What is procedural attachment?
Slot values are computed using a procedure only when needed.
What are default values in semantic networks?
Inherited values unless explicitly overridden.
What is a disadvantage of semantic nets?
Logical inadequacy and difficulty in comparing objects or retrieving knowledge.
How can semantic nets be improved?
By integrating nodes and attributes into a more structured format.
What is a frame?
A data structure representing stereotypical situations using slots and fillers.
What is a slot in a frame?
An attribute.
What is a filler in a frame?
A value or procedure associated with a slot.
What is an advantage of frames over semantic nets?
They organize complex objects hierarchically with easier access to attributes.
How do frames differ from objects?
Frames use prototypes and do not store code, only data with procedural attachments.
What is conceptual dependency?
A method to represent the meaning of sentences using primitive relations.
What are the 4 primitives in CD (Conceptual Dependency) Theory?
- ACT: action,
- PP (picture producer): object,
- AA (action aider): modifier of actions (how),
- PA (picture aider): modifier of objects (attribute).
What is a major limitation of CD?
Computationally expensive and sometimes cannot capture all meanings.
What is the canonical form in CD used for?
To compare different sentences by their meaning.
What is a script?
A representation of stereotypical sequences of actions in a situation.
What does a script consist of?
- Entry conditions,
- Results,
- Properties,
- Roles,
- Track,
- Scenes.
