![Fuzzy Set Model
• A fuzzy subset A of a universe of discourse U is
characterized by a membership function
• This function associates with each element u of U a
number μA(u) in the interval [0, 1]
• The three most commonly used operations on fuzzy
sets are:
– the complement of a fuzzy set
– the union of two or more fuzzy sets
– the intersection of two or more fuzzy sets](https://image.slidesharecdn.com/informationretrieval14fuzzysetmodelsofir-200610085904/85/Information-retrieval-14-fuzzy-set-models-of-ir-4-320.jpg)
Information retrieval 14 fuzzy set models of ir
- 1. Information Retrieval : 14 Fuzzy Set Models of IR Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. Fuzzy Set Model • Matching of a document to a query terms is approximate or vague • This vagueness can be modeled using a fuzzy framework, as follows: – each query term defines a fuzzy set – each doc has a degree of membership in this set • This interpretation provides the foundation for many IR models based on fuzzy theory • In here, we discuss the model proposed by Ogawa, Morita, and Kobayashi
- 3. Fuzzy Set Model • Fuzzy set theory deals with the representation of classes whose boundaries are not well defined • Key idea is to introduce the notion of a degree of membership associated with the elements of the class • This degree of membership varies from 0 to 1 and allows modelling the notion of marginal membership • Thus, membership is now a gradual notion, contrary to the crispy notion enforced by classic Boolean logic
- 4. Fuzzy Set Model • A fuzzy subset A of a universe of discourse U is characterized by a membership function • This function associates with each element u of U a number μA(u) in the interval [0, 1] • The three most commonly used operations on fuzzy sets are: – the complement of a fuzzy set – the union of two or more fuzzy sets – the intersection of two or more fuzzy sets
- 5. Fuzzy Set Model • Let, U be the universe of discourse • A and B be two fuzzy subsets of U • A be the complement of A relative to U • u be an element of U • Then,
- 6. Fuzzy Information Retrieval • Fuzzy sets are modeled based on a thesaurus, which defines term relationships • A thesaurus can be constructed by defining a term- term correlation matrix C
- 7. Fuzzy IR: An Example
- 8. Fuzzy IR: An Example
- 9. Fuzzy IR: An Example
- 10. Assignment • Explain the concept of Fuzzy Set models and Fuzzy Information Retrieval