Inteligenta Artificiala

1. Inteligenta Artificiala Universitatea Politehnica BucurestiAnul universitar 2005-2006 Adina Magda Florea http://turing.cs.pub.ro/ia_06

2. Curs nr. 13 Prelucrarea limbajului natural 2

3. Comunicare • Definite • mesaj, limbaj, protocol • Componentele comunicarii • intentie • generare • sinteza • perceptie • analiza • desambiguare • incorporare

4. Acte de comunicare • Teoria actelor de comunicare • locutie • ilocutie • prelocutie • asertive • directive • comisive • permisive • prohibitive • declarative • expresive Tipuri de agenti care comunica

5. Definire limbaj • Lexicon • Analiza lexicala • Gramatici • Analiza (pars oratoris) • Terminale, neterminale, reguli de rescriere • simbol de inceput • LHS  RHS • Analza semantica • Analiza pragmatica

6. LexiconNoun  breeze | wumpus | ballVerb  is | see | smell | hitAdjective  right | left | smelly …Adverb  here | there | ahead …Pronoun  me | you | I | itRelPronoun  that | whoName  John | Mary Article  the | a | an Preposition  to | in | on Conjunction  and | or | but

7. Gramatica • Neterminale – diferite categorii din propozitie • sentence S • noun phrase NP • verb phrase VP • prepositional phrase PP • relative clause RelClause

8. ExempluS  NP VP | S Conjunction SNP  Pronoun | Noun | Article Noun | NP PP | NP RelClauseVP  Verb | VP NP | VP Adjective | VP PP | VP AdverbPP  Preposition NPRelClause  RelPronoun VP

9. Analiza sintactica • top-down parsing • bottom-up parsing • in adancime • pe nivel

10. Top-Down Parsing"John hit the ball" 1. S 2. S  NP, VP 3. S  Noun, VP 4. S  John, Verb, NP 5. S  John, hit, NP 6. S  John, hit, Article, Noun 7. S  John, hit, the, Noun 8. S  John, hit, the, ball

11. Bottom-Up Parsing 1. John, hit, the, ball 2. Noun, hit, the, ball 3. Noun, Verb, the, ball 4. Noun, Verb, Article, ball 5. Noun, Verb, Article, Noun 6. NP, Verb, Article, Noun 7. NP, Verb, NP 8. NP, VP 9. S

12. Definite Clause Grammar (DCG) • Gramatici BNF - probleme • Utilizare LP • Gramatici cu clauze definite • DCG – gramatica; propozitie = clauza definita • neterminal = predicat de 1 argument

13. In BNF S  NP VPIn LPNP(s1)  VP(s2)  S(Append(s1, s2))NFNoun  ball | bookIn LP(s = “ball”  s = “book”)  Noun(s)

14. BNF, DCG, Prolog

15. Imbogatire DCG • Imbogatesc neterminale cu argumente suplimentare • Verifica corectitudinea gramaticala • Ataseseaza semantica • Adauga expresii / functii care se testeaza

16. DCG FOPL PROLOG S(sem)  NP(sem1) VP(sem2) {compose(sem1, sem2, sem)} NP(s1, sem1)  VP(s2, sem2)  S(append(s1, s2)), compose(sem1, sem2, sem) slide urmator Argument pt semantica semantica compozitionala

17. The dog has legs. (dog parts legs) The ball is yellow. (ball property yellow) The ball is red. (ball property red) The dog bites. (dog action bytes) sentence(S, Sem) :- np(S1, Sem1), vp(S2, Sem2), append(S1, S2, S), Sem = [Sem1 | Sem2]. np([S1, S2], Sem) :- article(S1), noun(S2, Sem). vp([S], Sem) :- verb(S, Sem1), Sem = [action, Sem1]. vp([S1, S2], Sem) :- verb(S1,_), adjective(S2, Sem1), Sem = [property, Sem1]. vp([S1, S2], Sem) :- verb(S1,_), noun(S2, Sem1), Sem = [parts, Sem1]. noun(dog,dog). noun(ball,ball). verb(bytes,bytes). verb(is,is). verb(has,has). adjective(yellow,yellow). adjective(red,red).

18. Verificare corectitudine gramaticala • cazuri • subcategorii verbe: compleentul pe care il poate accepta un verb • acord subiect predicat • etc. • Parametrizarea neterminalelor

19. Cazuri Nominativ (subjective) I take the bus Eu iau autobuzul You take the bus Tu iei autobuzul He takes the bus El ia autobuzul Acuzativ (objective) He gives me the book Imi da cartea S  NP(Subjective) VP NP(case)  Pronoun (case) | Noun | Article Noun // I VP  VP NP(Objective) // believe him VP  VP PP // turn to the right VP  VP Adjective VP  Verb PP  Preposition NP(Objective) Pronoun(Subjective)  I | you | he | she Pronoun(Objective)  me | you | him | her

20. sentence(S) :- np(S1,subjective), vp(S2), append(S1, S2, S).np([S], Case) :- pronoun(S, Case).np([S], _ ) :- noun(S).np([S1, S2], _ ) :- article(S1), noun(S2).pronoun(i, subjective).pronoun(you, _ ).pronoun(he, subjective).pronoun(she, subjective).pronoun(me, objective).pronoun(him, objective).pronoun(her, objective).noun(ball).noun(stick).article(a).article(the).

21. Subcategorii verbe • Lista de subcategorii: ce complemente accepta verbul • depinde de verb • S  NP(Subjective) VP(subcat) dar cazuri in care nu depinde • VP(subcat)  VP(subcat) PP • | VP(subcat) Adverb I smell the wumpus now

22. VP(subcat)  {subcat = np} VP(np) NP(Objective) | {subcat = adj} VP(adj) Adjective | {subcat = pp} VP (pp) PP | Verbsmell [NP] smell a wumpus [Adjective] smell awfull [PP] smell like a wumpusis [Adjective] is smelly [PP] is in box [NP] is a pitgive [NP, PP] give the gold in box to me [NP, NP] give me the golddied [] died

23. S  NP(Subjective) VP(subcat)NP(case)  Pronoun (case) | Noun | Article NounPronoun(Subjective)  I | you | he | shePronoun(Objective)  me | you | him | herVP(subcat)  {subcat = np} VP(np) NP(Objective) | {subcat = adj} VP(adj) Adjective | {subcat = pp} VP (pp) PP | Verb | VP(subcat) PP | VP(subcat) Adverb

24. sentence(S) :- np(S1,subjective), vp(S2), append(S1, S2, S).np([S], Case) :- pronoun(S, Case).np([S], _ ) :- noun(S).np([S1, S2], _ ) :- article(S1), noun(S2).VP(subcat)  VP(subcat) … !!!vp(S, Subcat) :- Subcat=np, vp1(S1, np),np(S2, objective), append(S1, S2, S).vp1([S],np):-verb(S).verb(give).verb(make).vp(S,Subcat) :- vp1(S1, Subcat), pp(S2), append(S1, S2, S).

25. Analiza pragmatica • Analiza semantica • Desambiguare • Interpretare pragmatica – utilizare si efect asupra ascultatorului • Indexical - situatia curenta • Anafora – deja mentionate

26. Ambiguitate • Lexicala • Sintactica • Referentiala • Pragmatica