1. CS621 : Artificial Intelligence Pushpak Bhattacharyya CSE Dept., IIT Bombay Lecture 9 Continuation of Logic and Semantic Web

2. AI’s view of knowledge Data Information Knowledge Wisdom Increasing Complexity, Sophistication and Refinement. Every level Contains information On HOW the lower Level is USED

3. Fundamental Triple E.g., And so on

4. Review of Predicate Calculus

5. Predicate Calculus Introduction through an example (Zohar Manna, 1974): Problem: A, B and C belong to the Himalayan club. Every member in the club is either a mountain climber or a skier or both. A likes whatever B dislikes and dislikes whatever B likes. A likes rain and snow. No mountain climber likes rain. Every skier likes snow. Is there a member who is a mountain climber and not a skier? Given knowledge has: Facts Rules

6. Predicate Calculus: Example contd. Let mc denote mountain climber and sk denotes skier. Knowledge representation in the given problem is as follows: 1. member(A) 2. member(B) 3. member(C) 4. ∀ x[member(x) → (mc(x) ∨ sk(x))] 5. ∀ x[mc(x) → ~like(x,rain)] 6. ∀ x[sk(x) → like(x, snow)] 7. ∀ x[like(B, x) → ~like(A, x)] 8. ∀ x[~like(B, x) → like(A, x)] 9. like(A, rain) 10. like(A, snow) 11. Question: ∃ x[member(x) ∧ mc(x) ∧ ~sk(x)] We have to infer the 11 th expression from the given 10. Done through Resolution Refutation.

7. 7 10 125 13 4 142 11 15 1613 17 2

8. Ontology

9. Taxonomic organization of knowledge

10. Simple Inference

11. Fundamental relationships Hypernymy Subclass (man mammal Membership (Ram ε man) Meronymy (part whole) (hand part-of body)

12. Markup (embeds meta- information) I just got a new dog I just got a new pet dog.

13. Namespace Give meaning to a name Specifically, bind a name with an URI (uniform resource identifier in the web) Pushpak http://www.cse.iitb.ac.in/~pb {person} Pushpak http://www.imdb.com/title/tt0251355/ {movie}

14. Draw the names from the namespace I just got a new pet dog.

15. RDF: Resource Description Format Each RDF statement has three parts: a subject, a predicate and an object Makes statements about resources on the web, uniquely identified by URIs

16. Example (from W3C specification of RDF) In natural Language http://www.example.org/index.html has a creator whose value is John Smith http://www.example.org/index.html has a creation-date whose value is August 16, 1999 http://www.example.org/index.html has a language whose value is English

17. Subject-Predicate-Object based scheme the subject is the URL http://www.example.org/index.html the predicate is the word "creator" the object is the phrase "John Smith"

18. More concretely through URIs a subject http://www.example.org/index.html a predicate http://purl.org/dc/elements/1.1/creator and an object http://www.example.org/staffid/85740

19. In graphical form

20. With all other information

21. In triple notation Subject http://www.example.org/index.html http://purl.org/dc/elements/1.1/creator> http://purl.org/dc/elements/1.1/creator http://www.example.org/staffid/85740 Predicate http://www.example.org/index.html "August 16, 1999". Object http://www.example.org/index.html http://purl.org/dc/elements/1.1/language "en".