1. Music AI Lecture 3 More on Knowledge Representation (anaparastasi gnosis) Introduction to searching (anazitisi)

2. Overview  Forwards and backwards deduction  More on Semantic nets  Frames and scripts  Grammars and syntactic trees in NLP  Break  Introduction to searching  Exercises  Reading for next week

3. Forwards deduction  Knowledge base: Mary coughs. Mary has temperature. Mary and John are together. Is someone coughs and has temperature, then he has a cold. If someone is together with someone else, then the someone else is together with the someone. (?!) If someone has a cold and is together with someone else, then this someone else also has a cold.  Task 1: Translate the above into a KR formalism.

4. Forwards deduction  Knowledge base: coughs(mary).has_temperature(mary).together(mary,john). coughs(X) ^ has_temperature(X)  hascold(X) together(Plato, Socrates)  together(Socrates,Plato) hascold(A) ^ together(B,A)  hascold(B)  Task 2: Prove that John has a cold

5. Forwards deduction: write here the correct answer

6. Tips for deductions:  In predicate unification, make sure the names of predicates match exactly.  You don’t have to use all the facts and rules in the knowledge base to prove something.  Don’t get confused with variable names. Variables start with a capital, and if they are confusing, substitute them with X,Y etc.  If you are unsure, write down what you want to say in English. Then translate it into predicate logic notation.

7. Backwards deduction Knowledge base:  coughs(mary).  has_temperature(mary).  together(mary,john).  coughs(X) ^ has_temperature(X)  hascold(X).  together(Plato, Socrates)  together(Socrates,Plato).  hascold(A) ^ together(B,A)  hascold(B).  goes_swimming(Snoopy)  hascold(Snoopy).  hascold(Beast) ^ together (Beauty, Beast)  takes_care(Beauty, Beast).  hascold(Cold) ^ drinks_from_same_glass(Hot, Cold)  hascold(Hot).  weather(freezing)  hascold(House).  hastemperature(mary)  says_nonsense(mary). (What is the problem with the last rule?)

8. Backwards deduction  Task: Using the above KB, prove that John has a cold. In doing that, show all the options of rules and where they lead to.

9. Backwards deduction: Write down the answer here

10. Semantic Networks, frames and scripts

11. Task In groups, think of a different example of a frame, and of a script. Write it out into some detail.

12. Syntactic rules so far:  s  np, vp.  np  det, n.  np  n.  vp  v.  vp  v, np.

13. Task: Draw the syntactic tree:  The baby cries.  Obelix ate the Roman.

14. Ungrammatical sentences :  A sentence that cannot be explained with our grammar is Ungrammatical.  Which of the following are ungrammatical? I am reading.I am reading. Tarzan kissed Jane in the rain.Tarzan kissed Jane in the rain. I hate Mondays.I hate Mondays. A dictionary of philosophy.A dictionary of philosophy. Sing!Sing! The book is on the shelf.The book is on the shelf. Chris wears glasses.Chris wears glasses.

15. Searching (anazitisi)  Lets play tic tac toe (triliza)...  What is a search space? (xwros anazitisis)  What is a search tree? (dentro)  What is a search strategy? (stratigiki)  What is depth first search (DFS)? (kata vathos)  What is breadth first search (BFS)? (kata platos)  What is a heuristic? (euristiki sinartisi)  How can we use heuristics to cut down the search tree?

16. Task: Think of a favourite game or problem that needs solving. Create the (part of) the first two levels of the search space in a tree diagram.

17. Reading for next week  Revise everything so far  Question: Can we devise grammars for music? (200-300 words)