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Inteligenta Artificiala

Inteligenta Artificiala. Universitatea Politehnica Bucuresti Anul universitar 2006-2007 Adina Magda Florea http://turing.cs.pub.ro/ia_07. Curs nr. 13. Prelucrarea limbajului natural. 2. Comunicare.

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Inteligenta Artificiala

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  1. Inteligenta Artificiala Universitatea Politehnica BucurestiAnul universitar 2006-2007 Adina Magda Florea http://turing.cs.pub.ro/ia_07

  2. Curs nr. 13 Prelucrarea limbajului natural 2

  3. Comunicare • Definitie: schimbul intentional de informatie generat de producerea si perceperea semnelor dintr-un sistem partajat de semne conventionale • 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 • parsing = inferenta logica

  13. In BNF S  NP VPIn LPNP(s1)  VP(s2)  S(Append(s1, s2))BNFNoun  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. (caine parti picioare) The ball is yellow. (minge proprietate galbena) The ball is red. (mine proprietate rosie) The dog bites. (caine actiune musca) 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 = [actiune, Sem1]. vp([S1, S2], Sem) :- verb(S1,_), adjective(S2, Sem1), Sem = [proprietate, Sem1]. vp([S1, S2], Sem) :- verb(S1,_), noun(S2, Sem1), Sem = [parti, Sem1]. noun(dog,caine). noun(ball,ball). noun(legs,picioare). verb(bytes,musca). verb(is,este). verb(has,are). adjective(yellow,galbena). adjective(red,rosie). ?- sentence([the,ball,is,yellow],Sem). Sem = [minge, proprietate, galbena] Yes ?- sentence([the,dog,bytes],Sem). Sem = [caine, actiune, musca] Yes ?- sentence([is,dog,bytes],Sem). No ?- sentence([the,dog,has,legs],Sem). Sem = [caine, parti, picioare] Yes

  18. Verificare corectitudine gramaticala • cazuri • subcategorii verbe: complementul 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. VP(subcat) {subcat = np} VP(np) NP(Objective) | {subcat = adj} VP(adj) Adjective | {subcat = pp} VP (pp) PP | Verb | VP(subcat) PP | VP(subcat) Adverb sentence(S) :- np(S1,subjective), vp(S2, Subcat), append(S1, S2, S).VP(subcat)  VP(subcat) … !!!vp(S, Subcat) :- Subcat=np, vp1(S1, np),np(S2, objective), append(S1, S2, S).vp(S,Subcat) :- vp1(S1, Subcat), pp(S2), append(S1, S2, S).vp1([S],np):-verb(S).verb(give).verb(make).

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

  26. Ambiguitate • Lexicala – acelasi cuvant diverse intelesuri • Sintactica – arbori diferiti de analiza • Referentiala – referire la obiecte anerioare • Pragmatica – referire la loc, timp

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