Semantic network

Draft

Definition

Semantic networks are a form of knowledge representation.

“A semantic network or net is a graphic notation for representing knowledge in patterns of interconnected nodes and arcs. Computer implementations of semantic networks were first developed for artificial intelligence and machine translation, but earlier versions have long been used in philosophy, psychology, and linguistics.” (Sowa, retrieved 18:03, 14 August 2007 (MEST).

“Knowledge representation is an issue that arises in both cognitive science and artificial intelligence. In cognitive science it is concerned with how people store and process information. In artificial intelligence (AI) the primary aim is to store knowledge so that programs can process it and achieve the verisimilitude of human intelligence.” (Wikipedia, retrieved 18:03, 14 August 2007 (MEST)).

In cognitive theory

For some authors knowledge is stored either in episodic or semantic memory. The further is organized in spacio-temporal dimensions, the second according semantic content-oriented principles, e.g. networks of concepts.

In computer science

In computer science, a semantic network can be defined as a knowledge representation formalism which describes objects and their relationships in terms of a network consisting of labelled arcs and nodes.

• “A semantic network is often used as a form of knowledge representation. It is a directed graph consisting of vertices which represent concepts and edges which represent semantic relations between the concepts.” (Wikipedia, retrieved 18:03, 14 August 2007 (MEST)).

• “A semantic network is a knowledge representation tool consisting of a framework of semantically related terms, with the purpose of allowing a definition of those words through their relationships.” ([1], retrieved 18:03, 14 August 2007 (MEST)).

Cognitive semantic networks

History

In the Collins and Quillian (69) model semantic nets are composed of simple concepts, concrete-abstract (is-a, ako) relations and part-whole (attribute, is, has, can) relations. E.g.

Parts of the knowledge about the concept Ms. X, member of parliament could be represented as follows:

     human
       ^
       |                
       |              politician --is--> in party y
       |                  ^
     is-a                 |
       |                 is-a
       |                  |
       |                  |
    Ms. X ----is--------> MP ---can---> vote in p.

Rummelhart and Ortony

The schema theory of Rumelhart and Ortony (1977) claims that personal knowledge is stored in information packets or schemas that comprise our mental constructs for ideas. Each schema we construct represents a mini-framework in which to interrelate elements or attributes of information about a topic into a single conceptual unit. These mini-frameworks are organized by the individual into a larger network of interrelated constructs known as a semantic network. These networks are composed of nodes: representations of schemas. Ordered labelled relationships define the propositional relationship between the nodes. Chris Muller, retrieved 18:03, 14 August 2007 (MEST).

In computing

See the Wikipedia] article for now ....

In education

The hypothesis for educational technologists is that mapping the semantic network of an expert or knowledgeable person onto the structure of a hypertext and then exposing the learner's to it will contribute to the development of the learner's knowledge structures

Research shows that semantic networks are somewhat transferable: as a result of instruction, learners' knowledge structures more closely resemble the instructor's knowledge structure. So, learners are acquiring two things during instruction:

• isolated knowledge
• knowledge structures that mimic the teacher's knowledge structure

See also: Educational use of concept maps and concept learning

Links

• John F. Sowa's website (inventor of conceptual graphs).

Literature

• Jonassen, David H. and Sherwood Wang (1993), Acquiring Structural Knowledge from Semantically Structured Hypertext. Journal of Computer-Based Instruction, Winter 1993, Vol. 20, No. 1, 1-8.

• Maida, Anthony S., & Stuart C. Shapiro (1982) "Intensional concepts in propositional semantic networks," Cognitive Science 6:4, 291-330.

• Sowa, John, F. Semantic Networks, Rrevised and extended version of an article that was originally written for the Encyclopedia of Artificial Intelligence, HTML, retrieved 18:03, 14 August 2007 (MEST).