Pathologies of Neural Models Make Interpretations Difficult

Transcript

1. ൃදऀ
   ୩ޱହ࢙ ҟৗͳڍಈ
2. !2 Pathological behavior ࣭໰จ͕did͚ͩͰ΋ Ϟσϧͷग़ྗ͸ಉ͡
   
   ֬౓΋ߴ͍
3. ֓ཁ w NLPʹ͓͚ΔχϡʔϥϧϞσϧͷղੳख๏ΛఏҊ
   w Ϟσϧ͕λεΫΛղ্͘Ͱॏཁͳ୯ޠΛநग़͢Δख๏
   w நग़͞Εͨ୯ޠ͸ਓʹͱͬͯ͸ҙຯෆ໌
   w ҰํͰϞσϧ͸நग़୯ޠͰ΋ਖ਼͘͠༧ଌ
   (Pathology) w ղੳ݁Ռʹجͮ͘ਖ਼ଇԽ߲ΛఏҊ
   w ਖ਼ଇԽ߲ʹΑͬͯϞσϧͷղऍੑ͸޲্ !3
4. ໨࣍  Ϟσϧղੳͷطଘख๏
    ఏҊख๏
    ࣮ݧ
    ·ͱΊ !4
5. Ϟσϧղੳͷطଘख๏
6. Ϟσϧղੳͷطଘख๏ !6 Adversarial Example Ϟσϧʹਓͷ௚ײʹ൓͢ΔڍಈΛͤ͞Δαϯϓϧ
   NLPͷλεΫ
   ओʹQAλεΫ
   Ͱ͸ύλʔϯ
    ਓʹͱͬͯ͸ҙຯͷͳ͍มߋ͕ɺϞσϧͷग़ྗΛܹมͤ͞Δέʔε
    ਓʹͱͬͯ͸໌Β͔ͳมߋͰ΋ɺϞσϧ͕ग़ྗΛม͑ͳ͍έʔε
7. ग़ྗ͕ܹม͢Δέʔε !7 Jia et al., 2017 ΫΥʔλʔόοΫͷ೥ྸʹ͍ͭͯͷ จॻʹΫΥʔλʔόοΫͷഎ൪߸ʹ ؔ͢ΔจΛ௥Ճ Ϟσϧ͸ޡ౴
8. ग़ྗΛม͑ͳ͍έʔε !8 Mudrakarta et al., 2018 ݐ෺ͷന͍ϨϯΨ͕ରশ͔ʁ spherical (ٿঢ়ͷ) ݐ෺ͷന͍ϨϯΨ͕ٿঢ়͔ʁ ࣭໰จͷҙຯมԽ Ϟσϧͷ༧ଌ͸ෆม
9. 2. ఏҊख๏
10. *OQVU
    3FEVDUJPO • ॏཁͰͳ͍୯ޠΛೖྗ͔Β࡟ΓɺϞσϧͷڍಈΛ෼ੳ • Ϟσϧ͕ਖ਼͍͠ग़ྗΛ͢ΔͨΊʹඞཁͳ࠷௿୯ޠ (ॏཁ ୯ޠ) • Adversarial Example͸Ϟσϧʹͱͬͯͷॏཁ୯ޠʹண໨
11. *OQVU
    3FEVDUJPO !11 x y Ϟσϧͷ༧ଌ f( ⋅ ) χϡʔϥϧϞσϧ ೖྗܥྻ (จ΍จॻ) xi ೖྗܥྻͷ͋Δཁૉ (୯ޠ) g(xi |x) = f(y|x) − f(y|x−i ) ͋Δ୯ޠ
    
    
    
    
    ʹର͢Δ ॏཁ౓
    
    Λఆٛ xi g i൪໨ͷ୯ޠΛফͨ͠ೖྗ
12. *OQVU
    3FEVDUJPO !12 g(xcontest |x) = f(y|x) − f(y|x−contest ) What company won free advertisement due to QuickBooks contest ? What company won free advertisement due to QuickBooks contest ? g͕େ͖͚Ε͹ɺcontest͕ॏཁͳ୯ޠͱͳΔ
    Ϟσϧͷग़ྗʹେ͖͘د༩͍ͯ͠ΔͨΊ
13. *OQVU
    3FEVDUJPO !13 g(xi |x) = f(y|x) − f(y|x−i ) ॏཁ౓ͷ௿͍୯ޠΛ࡟আ y͕มԽ͠ͳ͍Α͏ʹɺg͕࠷খͱͳΔ୯ޠiΛ࡟আ ͍ͯ͘͠
14. 3. ࣮ݧ
15. ղੳͷର৅λεΫ 1. SQuAD w จॻͱ࣭໰จ͕༩͑ΒΕΔ
    ˠ
    ࣭໰จʹରͯ͠Input Reduction w จॻ͔Βղ౴Λநग़͢ΔλεΫ
    2. SNLI w จ͕༩͑ΒΕΔ
    ˠ
    ͭͷจʹରͯ͠Input Reduction
    w จͷؔ܎Λਪఆ͢ΔλεΫ
    3. VQA w ը૾ͱ࣭໰จ͕༩͑ΒΕΔ
    ˠ
    ࣭໰จʹରͯ͠Input Reduction
    w ղ౴Λੜ੒͢ΔλεΫ !15
16. ࣮ݧ಺༰ Input Reduction w Ϟσϧ͕ਖ਼͍͠ग़ྗΛ͢ΔαϯϓϧΛର৅ʹ࣮ݧ
    w Input ReductionΛద༻ͨ͠ೖྗ
    (Reduced)
    ʹର͢ΔਓखධՁ
    w ReducedͱϥϯμϜʹ୯ޠΛམͱͨ͠৔߹
    (Random)
    ͷࠩҟͷධՁ
    Regularization on Reduced Inputs w Input ReductionʹΑΔϞσϧͷPathological behaviorΛܰݮ͢Δਖ਼ଇԽ߲
    ޙड़
    ͷಋೖ !16
17. Reducedʹର͢ΔਓखධՁ !17 Reducedʹରͯ͠
    ਓ͸ਖ਼͍͠༧ଌΛͰ ͖ͳ͍ w Reducedʹର͢Δਓͷਖ਼౴཰
    w Ϟσϧͷਖ਼౴཰͕ͷαϯϓϧΛ࢖༻
18. Reducedʹର͢ΔਓखධՁ !18 w ReducedͱRandomͷͲͪΒ͕ࣗવͳจ͔
    w vs. Random͸fifty-fiftyͱ౴ׂ͑ͨ߹ Reduced͸ਓʹͱͬ ͯ͸Randomͱಉ͡
19. Reducedͷࣄྫ !19 ʮͲ͜Ͱ࿅शͨ͠ ͔ʯΛฉ͔Ε͍ͯ Δͷ͸Θ͔Δ͕ɺ ʮͲͷνʔϜʯ͔ Θ͔Βͳ͍
20. Reducedͷฏۉ୯ޠ਺ ͭͷλεΫͱ΋ɺ
    ਖ਼౴͢Δͷʹඞཁͳ୯ޠ਺͸ฏۉd
21. Reducedʹର͢ΔϞσϧͷ֬౓ !21 • Input Reductionͷద༻લޙͰϞσϧͷ ֬౓ʹมԽ͸΄ͱΜͲͳ͍ • Ϟσϧ͸Ӷ͍ϐʔΫΛ࣋ͭΑ͏ͳ෼෍ Λֶश͍ͯ͠Δ͜ͱ͕ݪҼ
22. ਖ਼ଇԽ߲ͷಋೖ !22 ∑ (x,y)∈(X,Y) log(f(y|x)) + λ∑ ¯ x∈ ¯ X H(f(y| ¯ x)) Reducedʹରͯ͠ਖ਼͍͠yΛ
    ग़ྗ͠ʹ͘͘͢Δ ௨ৗͷ໨తؔ਺ Reducedαϯϓϧ͸௨ৗͷ໨తؔ਺Λ࢖ֶͬͯशͨ͠
    ϞσϧΛ༻͍ͯੜ੒
23. ਖ਼ଇԽ߲ͷޮՌ !23 • Ϟσϧͷਫ਼౓͕ඍ૿ • ਖ਼౴ʹඞཁͳ୯ޠ਺ ͕૿Ճ
24. ਖ਼ଇԽ߲ͷޮՌ !24 ਓखධՁͷਫ਼౓΋޲্ Input Reductionͨ͠ೖྗ ͷղऍੑ͕޲্
25. ਖ਼ଇԽͨ͠Ϟσϧͷࣄྫ !25 Input Reductionͨ͠ೖྗ͕ਓͰ΋ ղऍՄೳʹͳͬͨ
26. ·ͱΊ ఏҊख๏ w NLPͷχϡʔϥϧϞσϧղੳख๏ͱͯ͠ɺInput ReductionΛఏҊ
    w ༧ଌʹد༩͠ͳ͍୯ޠΛೖྗ͔Β࡟ΓɺϞσϧΛղੳ
    ࣮ݧ݁Ռ
    w ఏҊख๏Λద༻ͨ͠ೖྗ͸ਓʹͱͬͯҙຯෆ໌
    w ҰํͰχϡʔϥϧϞσϧ͸ਖ਼͍͠༧ଌΛߦ͏
    w ਖ਼ଇԽ߲Λಋೖ͢ΔͱϞσϧͷڍಈ͸վળ !26