1 / 22

Synonymies and conceptual vectors

Synonymies and conceptual vectors. NLPRS 2001 Mathieu Lafourcade, Violaine Prince LIRMM - France. Overwiew & Objectives. why synonymy? what : Conceptual vectors which synonymies ? for what : Use with lexical functions. Objectives. Evaluation

vkratzer
Download Presentation

Synonymies and conceptual vectors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Synonymies and conceptual vectors NLPRS 2001 Mathieu Lafourcade, Violaine Prince LIRMM - France

  2. Overwiew & Objectives why synonymy? what : Conceptual vectors which synonymies ? for what : Use with lexical functions

  3. Objectives • Evaluation • Semantic proxymity to possible contexts for lexical interchangeability • Relative synonymy • Elimination of transitivity punctum proximum • Subjective synonymy punctum remotum

  4. Conceptual vectorsvector space • An idea Concept combination — a vector • Idea space = vector space • A concept = an idea = a vector V with augmentation: V + neighboorhood • Meaning space = vector space + {v}* 

  5. Conceptual vectors Thesaurus • H : thesaurus hierarchy — K concepts Thesaurus Larousse = 873 concepts • V(Ci) : <a1, …, ai, … , a873> aj = 1/ (2 ** Dum(H, i, j)) 1/16 1/16 1/4 1 1/4 1/4 1/64 1/64 4 2 6

  6. Conceptual vectors Conceptc4:peace peace conflict relations hiérarchical relations society The world, manhood

  7. Conceptual vectors Term “peace” c4:peace

  8. Angular distance • DA(x, y) = angle (x, y) • 0  DA(x, y)  • if 0 then x & y colinear — same idea • if /2 then nothing in common • if  then DA(x, -x) with -x — anti-idea of x x’ x  y

  9. Angular distance DA(x, y) = acos(sim(x,y)) DA(x, y) = acos(x.y/|x||y|)) DA(x, x) = 0 DA(x, y) = DA(y, x) DA(x, y) + DA(y, z)  DA(x, z) DA(0, 0) = 0 and DA(x, 0) = /2 by definition DA(x, y) = DA(x, y) with   0 DA(x, y) =  - DA(x, y) with  < 0 DA(x+x, x+y) = DA(x, x+y)  DA(x, y)

  10. Thematic distance • Examples • DA(tit, tit) = 0 • DA(tit, passerine) = 0.4 • DA(tit, bird) = 0.7 • DA(tit, train) = 1.14 • DA(tit, insect) = 0.62 tit = insectivorous passerine bird …

  11. Relative synonymyAspectual or referential • Term polysemy • un personnel trié sur le volet (CHOISIR) • une liste triée par ordre alphabétique (ORDONNER) • le courrier est trié (REPARTIR) • A vector plays as an aspect (aka reference) • How can we exchange A & B in the context of C ?

  12. Relative synonymy • SynR(A, B, C) with C as a reference (ref) SynR(A, B, C) = DA(A+AC, B+BC) A+AC SynR(A, B, C) A B+BC C B

  13. Relative synonymyProperties • SynR(A, B, C) = SynR(B, A, C) • SynR(A, A, C) = DA(A  C, A  C) = 0 • SynR(A, B, 0) = DA(A, B • SynR(A, 0, C) = /2 • DA(charbon,nuit) = 0.9 • SynR(charbon, nuit, couleur) = 0.4 • SynR(charbon, nuit, noir) = 0.35

  14. Relative synonymyProperties • The relative synonymy is a measure which favors the closing in of 2 vectors: “black” a good punctum proximum for “coal” and “night” • Transitivity of the synonymy • SynR(coal, crow, black) = 0.18 • SynR(crow, night, black) = 0.5 • SynR(coal, night, black) = 0.35

  15. Absolute synonymy • SynA(A, B) a particular case with AB as ref SynA(A, B) = SynR (A, B, AB) A+A(AB) SynA(A, B) A AB B+B(AB) B

  16. Subjective synonymyPoint of view • Semantic discrimination scope • DA(tit, bird) = 0.7 • DA(sparrow, bird) = 0.48 • DA(tit, sparrow) = 0.23 • With which pow can we discriminate two given vectors? Closest “punctum remotum”

  17. Subjective synonymy • SynS(A, B, C) — C = point of view (pow) SynS(A, B, C) = D(A-AC, B-BC) A A-AC C B SynS(A, B, C) B-BC

  18. Subjective synonymy When DA(A, C)  /2 & DA(B, C)  /2 then SynS(A, B, C)  DA(A,B) SynS(A, B, 0) = DA(A, B) SynS(A, A, C) = 0 SynS(A, B, B) = DA(A-AB, 0) = /2 • DA(tit, crow) = 0.32 • SynS(tit, crow, zoology) = 0.54 • SynS(tit, crow, bird) = 1.07 • SynS(tit, crow, passerine) = 1.37

  19. Subjective synonymyProperties • non conservation of the concept hierarchy chain Concept chain • @the_world > @the_life > @animals > @birds • DA(tit, sparrow) = 0.23 • SynS(tit, sparrow, @the_life) = 0.75 • SynS(tit, sparrow, @the_world) = 0.5 • SynS(tit, sparrow, @animals) = 0.4 • SynS(tit, sparrow, @birds) = 0.9 Concepts horizon (at the lowest concept level)

  20. Subjective synonymyProperties • Polysemy: term vs concept • SynS(tit, sparrow, @birds) = 0.9 • SynS(tit, sparrow, bird) = 0.78 • Loosly correlated vectors as pow • SynS(tit, sparrow, @gold) = 0.7 • DA(tit, @gold) = 1.19 • DA(sparrow, @gold) = 1.15

  21. Objective synonymy A-A(AB) SynA(A, B) a particular case with AB as pow SynA(A, B) = SynA(A, B, AB) A AB B B-B(AB) SynA(A, B)

  22. Conclusion • Synonymy as enhancement of thethematic analysis • The conceptual vector models showsinterferencies • from polysemy : relative synonymy • from the complex relation btw concept and terms (bird vs @birds) • System in continuous learning • Evolving results • Hopefully converging

More Related