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データドリブンな組織の不正検知

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January 26, 2023

 データドリブンな組織の不正検知

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fkubota

January 26, 2023
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  1. Copyright Kanmu, Inc. All right reserved. 2 ٱอా ࢙༸ ML

    Engineer at Kanmu, Inc. @fkubota @fkubota_ ࣗݾ঺հ
  2. Copyright Kanmu, Inc. All right reserved. ػցֶशΤϯδχΞ fkubotaͷۀ຿಺༰ • ࣄۀΛ੒௕ͤ͞ΔखஈͷதͰσʔλͰͰ͖Δ͜ͱશൠ

    • ͦͷதͷҰ෦ʹML͕͋Δ • ϓϩμΫτ๊͕͍͑ͯΔ໰୊΍ղܾ͍ͨ͠Ϣʔβͷ௧ΈΛσ ʔλͰ໰୊ղܾͰ͖Δܗʹͯ͠ղ͘ͱ͍͏ͷ͕ͬ͘͟Γͱ ͨ͠ۀ຿ൣғ ࣄۀΛ੒௕ͤ͞Δखஈ σʔλͰͰ͖Δ͜ͱશൠ ML
  3. Copyright Kanmu, Inc. All right reserved. ʹ͍ͭͯ • ಛ௃Λ؆୯ʹ ◦

    1෼Ͱ࡞ΕΔVisaϓϦϖΠυΧʔυ ◦ 600ສμ΢ϯϩʔυಥഁ ◦ ޙ෷͍ػೳ͕͋Δ
  4. Copyright Kanmu, Inc. All right reserved. ϙνͬͱνϟʔδ • ϙνͬͱνϟʔδʹ͍ͭͯ ◦

    ޙ෷͍αʔϏε ◦ ਖ਼֬ʹ͸ɺηϒϯͷޙ෷͍αʔϏεΛόϯυϧΧʔυͷ ΞϓϦ಺Ͱ࢖༻Ͱ͖Δ
  5. Copyright Kanmu, Inc. All right reserved. ޙ෷͍αʔϏεͱ͸ • ࠓ͙͢ങ͍͍ͨͷʹ࢒ߴ͕଍Γͳ͍Αʙͱ͍͏ͱ͖ʹ࢖͑Δ •

    গֹ(3000ԁʙ50000ԁ)νϟʔδ͢Δ͜ͱ͕Ͱ͖Δ • ͦͷޙظݶ೔·ͰʹίϯϏχͳͲͰࢧ෷͍ • େ͖ͳಛ௃ͱͯ͠਎෼ূఏग़ΛߦΘͳͯ͘΋ར༻͢Δ͜ͱ͕ Ͱ͖Δ ◦ ※ ޙ෷͍αʔϏεΛఏڙ͢Δηϒϯ౳ͷ৹ࠪʹΑͬͯར༻Ͱ͖ͳ͍Ϣʔβʔ ͸ଘࡏ͢Δ
  6. Copyright Kanmu, Inc. All right reserved. ޙ෷͍αʔϏεͷෆਖ਼ • νϟʔδޙʹҙਤతʹࢧ෷͍Λ͠ͳ͍ •

    ૊৫తͳ൜ߦͳͲ΋͋Δ ࠓ೔͸ɺෆਖ਼νϟʔδͷ૿Ճ͕֬ೝ͞Εͨͱ͖ ʹɺνʔϜͰߦͬͨରࡦʹ͍͓ͭͯ࿩͠͠·͢ ϙνͬͱ νϟʔδ ܾࡁ ࢧ෷͍ ϙνͬͱ νϟʔδ ܾࡁ
  7. Copyright Kanmu, Inc. All right reserved. ෆਖ਼݅਺ͷ૿Ճ • ૊৫తͱݟΒΕΔෆਖ਼ͷ૿Ճ͕؍ଌ͞Εͨ •

    طଘͷෆਖ਼Λ๷͙ϧʔϧ͕ಥഁ͞Εͨͱ͍͏͜ͱ ◦ ๷͙ʹ͸Ͳ͏͢Δʁ
  8. Copyright Kanmu, Inc. All right reserved. ಛ௃Λݟ͚͍ͭͨ • ૊৫తͳͷͰɺͳʹ͔ڞ௨఺͕͋Δ͸ͣ •

    ྫ͑͹ɺશͯಉ͡υϝΠϯͷϝʔϧΞυϨεͷϢʔβ܈ͳΒ ؆୯ʹಛఆ͠ରࡦ͢Δ͜ͱ͕Ͱ͖Δ • ݱ࣮ʹ͸΋ͪΖΜͦ͜·Ͱ୯७Ͱ͸ͳ͍
  9. Copyright Kanmu, Inc. All right reserved. ͱʹ͔͘Ұ࣍৘ใΛݟΔ • Ճ޻͞Ε͍ͯͳ͍σʔλΛͱʹ͔͘ݟ·͢ɻ(టष͘) •

    ͳʹ͔ͱ͔͔ͬΓ͕௫ΊΕ͹ɺԾઆΛཱͯͯΫϩεूܭͳͲͰ σʔλΛ෼ੳ͠·͢ ◦ ͜ͷಛ௃ྔA ͷ a1~a5 ʹଐ͢ΔϢʔβ܈͕ո͍͠ͷͰ͸ʁʁ • ಘΒΕͨ৘ใ͔ΒԾઆΛΞοϓσʔτͯ͠·ͨσʔλΛݟΔ ֶͼ ͱ ڞ༗ ෼ੳ ੜσʔλ Ծઆ ͙Δ͙Δճ͢
  10. Copyright Kanmu, Inc. All right reserved. σʔλυϦϒϯͳνʔϜͰઓ͏ • ෼ੳΛ͍ͯ͠Δؒʹ΋ͲΜͲΜ࢖͑ͦ͏ͳσʔλީิ͕νʔ Ϝϝϯόʔ͔Βू·͖ͬͯ·͢

    • ΧϯϜ͸ࣾһͷ΄΅શһ͕SQLΛॻ͚ΔͷͰඞཁͳ৘ใ͸ ֤ࣗͰऔΓߦ͘ͱ͍͏จԽ͕͋Γ·͢ • ৬छʹΑͬͯීஈ࢖͏σʔλ(ςʔϒϧ)͕ҟͳΔͷͰɺ஌Β ͳ͔ͬͨ৘ใ͕ͨ͘͞Μू·Δ ΄΅શһ͕ɺ ϛχσʔλΞφϦετʁ ͜ͷϩάݟΕ͹ ͳʹ͔Θ͔ΔΜ͡Όͳ͍͔ͳ ͜ͷςʔϒϧͷ ͜ͷσʔλ࢖͑Δ͔΋ ໾һ Ϛʔέλʔ Πϯϑϥ σβΠφʔ PdM ϑϩϯτΤϯυ Biz/Dev
  11. Copyright Kanmu, Inc. All right reserved. ϝϯόʔ͔Βͷ৘ใఏڙͰѻ͏σʔλ͕ਂ͘޿͘ͳΔ • ෼ੳ݁Ռ͔Β৘ใΛڞ༗ͯ͠ •

    ͦΕΛݟͨඇ෼ੳઐ໳ͷϝϯόʔ͔Βίϝϯτ͕ଓʑͱ • ͦΕͰѻ͏σʔλͷ্࣭͕͕ͬͨΓ৽ͨͳԾઆཱ͕ͬͨΓ ֶͼ ͱ ڞ༗ ෼ੳ ੜσʔλ Ծઆ σʔλ΍஌ݟ ৘ใ
  12. Copyright Kanmu, Inc. All right reserved. ࢖͑ͦ͏ͳσʔλ͕Ұ௨ΓἧͬͨΒ • Ͳ͏͍͏໰୊Λղ͘΂͖͔ߟ͑Δ a.

    Ͳͷ࣌఺Ͱݕ஌͍ͨ͠ͷ͔ʁ(ෆਖ਼લʁɺෆਖ਼ޙʁ) b. ྑ͍ݕ஌ͱ͸ͳʹ͔ʁ(ධՁࢦඪ) c. ӡ༻໘
  13. Copyright Kanmu, Inc. All right reserved. a. Ͳͷ࣌఺Ͱݕ஌͍ͨ͠ͷ͔ʁ • ୔ࢁσʔλ͕͋ͬͯ΋ෆਖ਼ݕ஌λΠϛϯάʹΑͬͯ࢖͑ͳ

    ͍Մೳੑ΋͋ΔͷͰ৻ॏʹ(ϦʔΫ) • ͕࣌ؒܦա͢Δ΄Ͳ࢖͑Δ৘ใ͸ଟ͍ • ૣ͍λΠϛϯάͩͱෆਖ਼༧ଌͱͯ͠ػೳͯ͠ෆਖ਼͕ى͜Δ લʹࢭΊΒΕΔ • ଎౓ͱ৘ใྔͷτϨʔυΦϑ ొ࿥ ෆਖ਼ νϟʔδ ܾࡁ ? ? ? ? ? ৘ใྔ
  14. Copyright Kanmu, Inc. All right reserved. b. ྑ͍ݕ஌ͱ͸ͳʹ͔ • ෆਖ਼ͷΈΛશ݅ݟ͚ͭΔͷ͸ͱͯ΋Ή͔͍ͣ͠

    • શ݅ݟ͚ͭΑ͏ͱ͢Δͱ ◦ →ר͖ࠐΜͰ͠·͏Ϣʔβ͕૿͑Δ • ר͖ࠐ·ͳ͍Α͏ʹ͢Δͱ ◦ →ෆਖ਼Λಀͯ͠͠·͏ • Α͋͘Δ Precision vs Recall ໰୊ • ͋Δ1ͭͷධՁࢦඪͷ࠷େԽͰ୯७ʹܾΊΒΕͳ͍͜ͱ΋͋Δ • ͜͜͸టष͘
  15. Copyright Kanmu, Inc. All right reserved. c. ӡ༻໘ • ৽͘͠MLϞσϧΛ࡞ͬͯӡ༻͢Δʁ

    ◦ ݱঢ়͸ɺML͕࢖ΘΕ͍ͯΔͱ͜Ζ΋͋Δ͕࢖ΘΕ͍ͯͳ ͍ͱ͜Ζ΋͋Δ • ෆਖ਼͕૿͍͑ͯΔঢ়گͰ͸ɺૣ͘ରॲ͍ͨ͠ ◦ MLΛγεςϜʹ૊ΈࠐΉ࣌ؒ͸ͳ͍ʁ
  16. Copyright Kanmu, Inc. All right reserved. ࠓճͷղ͖͍ͨ໰୊͸ • 3ཁૉ ◦

    Ͳͷ࣌఺Ͱݕ஌͍ͨ͠ͷ͔ ▪ ͋Δఔ౓৘ใ͕ू·Δ࣌఺͔ͭɺΦϖϨʔγϣϯͷ؍఺͔Βܾఆ ◦ ྑ͍ݕ஌ͱ͸ͳʹ͔ ▪ ෆਖ਼Λݕ஌ͭͭ͠ɺଞͷϢʔβΛͰ͖Δ͚ͩר͖ࠐ·ͳ͍Α͏ʹ͢Δ ▪ ݶքརӹ΍աڈͷӡ༻͖ͯͨ͠ϧʔϧϕʔεͷܦݧ͔ΒɺνʔϜͰ૯߹త ʹ൑அˡ͋ΔҰͭͷࢦඪͷ࠷େԽͱ͍͏୯७ͳ໰୊Ͱ͸ͳ͍ ◦ ӡ༻໘ ▪ ࣮૷·Ͱͷ଎౓ɺ͜Ε·Ͱͷӡ༻ͱͷ਌࿨ੑɺਫ਼౓͔ΒMLϞσϧͰ͸ͳ ͘ɺϧʔϧϕʔεͰे෼ͩͱ൑அ • Next Action ◦ ݕ஌ͷλΠϛϯά͔Β࢖͑Δσʔλ͕ܾ·ͬͨɻ ◦ ͜ΕΒΛ࢖ͬͯɺଞͷϢʔβΛͰ͖Δ͚ͩר͖ࠐ·ͳ͍ܗͰෆਖ਼Λݕ஌Ͱ͖ ΔϧʔϧϕʔεΛܾఆ͢Δɻ
  17. Copyright Kanmu, Inc. All right reserved. ϧʔϧϕʔεͷܾఆ • ࢖͑ͦ͏ͳσʔλ(ಛ௃ྔ)͸ͨ͘͞Μ͋Δ •

    ͲΕΛϧʔϧͱͯ͠࢖͏͔ܾΊͳ͚Ε͹ͳΒͳ͍ ◦ ྫ: ಛ௃ྔA͕aҎ্Λෆਖ਼ͱ͢Δ • ͔͋͠͠Δಛ௃ྔ1ͭͰෆਖ਼ͩͱ൑அ͢Δ͚ͩͷܾఆతͳಛ ௃ྔ͸ݟ͔͍ͭͬͯͳ͍ • ෳ਺ͷಛ௃ྔΛ࢖ͬͨଟ࣍ݩతͳϧʔϧʹ͢Δඞཁ͕͋Δ ◦ ྫ: ಛ௃ྔA͕aҎ্ ͔ͭ ಛ௃ྔB͕bҎԼ ͔ͭ...
  18. Copyright Kanmu, Inc. All right reserved. ܾఆ໦Λ༻͍Δ • େྔͷ࢖͑ͦ͏ͳಛ௃ྔΛܾఆ໦ʹೖྗɺڭࢣσʔλ͸ 1(ෆਖ਼)

    / 0(notෆਖ਼) ͷೋ஋෼ྨ • ෆਖ਼͕ͨ͘͞Μؚ·ΕΔ͔ͭר͖ࠐΈ͕গͳ͍ऴ୺ϊʔυ͕͋Ε͹ͦͷϊ ʔυʹͨͲΓண͘·ͰͷϧʔϧΛͦͷ··ϧʔϧϕʔεʹ͢ΔΞϓϩʔν • ֤ϊʔυ͕ͦΕͧΕఏҊ͞Εͨϧʔϧͱߟ͑Δ͜ͱ͕Ͱ͖Δ featA > a ? featB > b ? featC > c ? not ෆਖ਼ ෆਖ਼ yes no ѱ͍ϧʔϧ ྑ͍ϧʔϧ ϧʔϧʹ͢Δͱ • featA <= a ͔ͭ featC <= c Λෆਖ਼ͱ͢Δ
  19. Copyright Kanmu, Inc. All right reserved. ϧʔϧͷܾఆ • ӡ༻໘΍ղऍͷ͠΍͢͞ͳͲ͔ΒϧʔϧΛܾఆ •

    ࠷ޙ͸ᮢ஋ͳͲΛաڈͷσʔλͰݟͳ͕ΒϩόετੑͳͲ΋ ߟྀ͠ඍௐ੔ • ͜Ε΋νʔϜ(ෆਖ਼؂ࢹઐ໳ϝϯόʔͳͲ)Ͱ૬ஊܾͯ͠ఆ featA > a ? featB > b ? featC > c ? not ෆਖ਼ ෆਖ਼ yes no ྑ͍ϧʔϧ ϧʔϧʹ͢Δͱ • featA <= a ͔ͭ featC <= c Λෆਖ਼ͱ͢Δ
  20. Copyright Kanmu, Inc. All right reserved. ܾఆ໦ͷ஫ҙ఺ • ໦͕ਂ͘ͳΔͱϧʔϧ͕ෳࡶʹͳΓ͗͢Δ •

    ໦͕ਂ͍ͱɺͦͷϊʔυͷෆ७౓͕Լ͕Δ͕ɺऴ୺ϊʔυʹؚ· ΕΔσʔλ਺͕গͳ͍ͷͰෆਖ਼Λଟ͘औΓಀ͕͢͜ͱʹ ◦ ܾఆ໦ͷਂ͞͸ɺ਺ύλʔϯࢼͤ͹͋ͨΓ͸͙͢ʹ෇͚ΒΕͨ • ӡ༻໘ɺղऍੑɺਫ਼౓ͳͲటष͘σʔλΛݟͳ͕ΒܾΊ͍ͯ͘ඞ ཁ͕͋Δ featA > a ? featZ > z ? not ෆਖ਼ ෆਖ਼ yes no ෆ७౓͸খ͍͕͞ɺ ଟ͘ͷෆਖ਼Λಀͯ͠ ͍Δྫ . . .
  21. Copyright Kanmu, Inc. All right reserved. ܾఆ໦͕ϕετ͔ʁ • ࠓճ͸ɺ༗ޮͳಛ௃ྔީิͱͦͷᮢ஋ͷ͋ͨΓ͕͚ͭΒΕ Ε͹Α͔ͬͨ

    • ݫີʹ΍ΔͳΒɺ੍໿෇͖ͷ࠷దԽ໰୊ͱͯ͠ղ͘ͷ͕ྑ ͍ͱࢥ͏͕͕͔͔࣌ؒΔ ◦ ࠓճ͸ɺௐ͔ࠪΒϧʔϧܾఆɺಋೖ·ͰӦۀ೔10೔ؒఔ ౓Ͱऩ·ͬͨ • ࠓճ͸ɺܾఆ໦Ͱे෼ͩͬͨ
  22. Copyright Kanmu, Inc. All right reserved. ·ͱΊ • σʔλυϦϒϯͳ૊৫ ◦

    ೔ʑͷҙࢥܾఆʹ͸جຊతʹσʔλ͋Γ͖ɻࢿྉʹ͸SQLͷΫ ΤϦ΋Ұॹʹ෇͍ͯ͘Δɻ(ඇΤϯδχΞͰ΋) ◦ ͜Ε͕పఈ͞Ε͍ͯΔͷͰɺଟํ໘͔Β࢖͑ͦ͏ͳσʔλ͕ू ·Δɻ • ෆਖ਼ݕ஌ͱ͍ͬͯ΋ɺͲ͏͍͏໰୊Λղ͖͍͔ͨʹΑͬͯΞϓϩ ʔν͕ҟͳΔ ◦ ղ͍ͯخ͍͠໰୊Λৗʹߟ͑Δ ◦ ਫ਼౓ͷߴ͍MLϞσϧ࡞ͬͯ΋࢖Θͳ͚Ε͹ҙຯ͕ͳ͍ • ϧʔϧϕʔεͷܾఆͷ͓ख఻͍ͱͯ͠MLϞσϧ(ܾఆ໦)Λ࢖༻ͨ͠