Recently MeroSpark is lunched with more features and services, now you can ask your question, sell your books, share your notes and many more. Visit https://www.merospark.com/signup/ now and create your account to take full advantage of MeroSpark.

Object-based Approach: Semantic Network | Advantages and Disadvantages

Download our Android App from Google Play Store and start reading Reference Notes Offline.

object based approach-semantic networkObject based approach:Semantic Network and O-A-V Triple:
Fourth Semester | Tribhuvan University (TU)
Subject: Cognitive Science | BSc.CSIT

Semantic Network
Semantic Networks and Frames are called Network Representations or Associative Representations.

Intuition: Knowledge is not a large collection of small pieces of knowledge but larger pieces that are highly interconnected. Logics and Rule-Based Systems seem to not have this property. The meaning of concepts emerges from how it is connected to other concepts.

Semantic networks can

  • show natural relationships between objects/concepts
  • be used to represent declarative/descriptive knowledge

Knowledge is represented as a collection of concepts, represented by nodes. Thus, semantic networks are constructed using nodes linked by directional lines called arcs

A node can represent a fact description

  • physical object
  • concept
  • event

An arc (or link) represents relationships between nodes. There are some ‘standard’ relationship types

  • ‘Is-a’ (instance relationship): represent class/instance relationships
  • ‘Has-a’ (part-subpart relationship): identify property relationships

Semantic networks are mainly used as an aid to analysis to visually represent parts of the problem domain.

One feature of a semantic net is the ability to use the net to deduce new facts

  • Begin with the fact that – all robins are birds
  • If Clyde is the name of a particular pet robin then
  • By following the is-a links it is easy to deduce that Clyde is a bird
    Deduced: Robins have wings and Clyde has wings

Disadvantages

  • incomplete (no explicit operational/procedural knowledge)
  • no interpretation standard
  • lack of standards, ambiguity in node/link descriptions
  • not temporal (i.e. doesn’t represent time or sequence)

Advantages

  • Explicit and easy to understand.
  • The net is its own index – quick inference possible.
  • Supports default reasoning in finite time.
  • Focus on bigger units of knowledge and interconnectedness.

O-A-V Triple:
Object – Attribute – Value (OAV) provides a particularly convenient way in which to represent certain facts and heuristic rules within KB. Each OAV triplet is present with specific entity, or object and a set of attributes with their values associated to every object.

(Visited 1,153 times, 1 visits today)

Posted By : Digvijay | Comment RSS | Category : Fourth Semester
Tag :

Post a Comment

Your email is never published nor shared. Required fields are marked *

*
*

Wordpress DMCA
Community | Toolbar | Android App | Founder/Developer : Hari Prasad Chaudhary | CSIT Portal Manager : Digvijay Chaudhary