Q21Principles of Artificial Intelligence
Question
Explain the conceptual dependency and semantic networks for knowledge representation.
Answer
Conceptual Dependency and Semantic Networks are graphical knowledge representation frameworks used to depict the meaning of sentences and relationships between concepts.
Knowledge Representation involves structuring information so that a computer system can process it intelligently. Two prominent graphical methods are Conceptual Dependency and Semantic Networks.
Semantic Networks:
A semantic network is a directed graph consisting of nodes, which represent objects or concepts, and links (edges), which represent semantic relations between them (e.g., 'IS-A', 'HAS-A'). It provides an intuitive way to represent taxonomies and inheritance. For example, a node 'Bird' might have an 'IS-A' link to 'Animal' and a 'HAS-A' link to 'Wings'.
Conceptual Dependency (CD):
Developed by Roger Schank, Conceptual Dependency represents the underlying meaning of a natural language sentence independent of the specific words used. It uses a set of primitive actions (e.g., ATRANS for transfer of abstract relationship, PTRANS for physical transfer, INGEST) to break down complex actions.
CD graphs show the actor, the action, the object being acted upon, and the direction of the action. This abstraction allows the system to recognize that 'John gave a book to Mary' and 'Mary received a book from John' share the identical core conceptual meaning.
