「LINE MUSIC」におけるハイブリッド検索や略称抽出を用いた曖昧検索への挑戦 / Challenges in Ambiguous Search Using Hybrid Search and Abbreviation Extraction in "LINE MUSIC"

$IBMMFOHFTJO"NCJHVPVT4FBSDI 6TJOH)ZCSJE4FBSDI BOE"CCSFWJBUJPO&YUSBDUJPO JO-*/&.64*$ Music Business Group / LY Corporation
Tada Taku, Mori Jumpei

About Speakers Tada Taku Music Business Group / LY Corporation
Backend Engineer Music Business Group / LY Corporation Backend Engineer Mori Jumpei

LINE MUSIC

LINE MUSIC Search Tab

Challenge ʮਖ਼֬ʹೖྗ͠ͳ͍ͱݕࡧͰ͖ͳ͍ʯ l*DBOOPUpOEBUSBDLVOMFTT*FOUFSJUFYBDUMZz "NCJHVPVT4FBSDI

Ø)ZCSJE4FBSDI Ø"MJBT(FOFSBUJPO Ø$PODMVTJPO Agenda

Ø Keyword Search Ø Issue Ø Traditional Method Ø Vector
Search Ø Hybrid Search Ø Architecture Ø Reranking Ø Summary Hybrid Search

Keyword Search ,FZXPSE4FBSDI TOPXGSPXFS TOPXGSPXFS <TOPX qPXFS GSPXFS ʜ> 4OPX'MPXFS

Issue 7BSJPVTFYQSFTTJPOT :VLJOPIBOB ઇͷՖ 4OPX'MPXFS :VLJOPIBOB ઇͷ՚ :VLJOPIBOB Ώ͖ͷ͸ͳ :VLJOPIBOB
ઇͷϋφ 4OPX'SPXFS εϊ΢ϑϥϫʔ 8IJUF'MPXFS *This is a fictitious song title and bears no relation to any existing or real-world music.

Traditional Method 'V[[Z4FBSDI /PSNBMJ[BUJPO &YQBOEJOH%JDUJPOBSZ ÅˠB ͋ˠΞ G PXFS ˣ
qPXFS GSPXFS < TOPXqPXFS XIJUFqPXFS TOPXqPVS ઇͷՖ ઇͷϋφ ʜ UPPNBOZ > MˠS GQPXFS

Vector Search 7FDUPS4FBSDI ,FZXPSE4FBSDI TOPXGSPXFS TOPXGSPXFS <TOPX qPXFS GSPXFS ʜ>
4OPX'MPXFS 4OPX'MPXFS

How to ensure quality in this major change?

How to ensure quality in this major change? )ZCSJE4FBSDI
,FZXPSE4FBSDI 7FDUPS4FBSDI in this minor change

Hybrid Search $POUFOU" $POUFOUT# $POUFOUT% $POUFOU# $POUFOU$ $POUFOU" $POUFOUT# $POUFOU$
$POUFOUT% ,FZXPSE4FBSDI3FTVMU 7FDUPS4FBSDI3FTVMU )ZCSJE4FBSDI3FTVMU

Architecture Search Server Text Embedding Server OpenSearch ,FZXPSE3FTVMU Keyword Search
)ZCSJE3FTVMU Query Query Vector 7FDUPS3FTVMU Vector Search /POpOFUVOFE NVMUJMJOHVBMFTNBMM Reranking

Reranking (Motivation) TOPXGSPXFS 4OPX'MPXFS 4OPX1PXEFS The order of vector search
results ≠ search results wanted by users Similarity (snow frower, Snow Flower) < Similarity (snow frower, Snow Powder) But users may want “Snow Flower”

Reranking (Approach) TOPXGSPXFS 4OPX'MPXFS 4OPX1PXEFS 4OPX'MPXFS'MPXFS 0.8 0.7 0.5 Score

Reranking (Core Logic) snow fower Longest Common Subsequence TOPXGSPXFS 4OPX'MPXFS
4OPX1PXEFS snow ower

Summary ⎯ Users input various expressions for a same content.
⎯ Vector Search is powerful method to resolve kind problem. ⎯ Hybrid Search can ensure minimum quality (= keyword search quality). ⎯ With rule based reranking, we can integrate non-fine-tuned ML model. ⎯ Our core logic is Longest Common Subsequence in reranking logic )ZCSJE4FBSDI

Ø"CPVUQSPCMFN Ø'JSTUJEFB Ø*NQSPWFNFOU Ø4PMVUJPO Ø1SPNQUUFDIOJRVFT Ø3FTVMUBOE4VNNBSZ Alias Generation

Problem: Search songs by tie-up aliases %3"(0/#"-- $)"-")&"%$)"-" An opening
song of the anime DRAGON BALL.

Problem: Search songs by tie-up aliases %3"(0/#"-- $)"-")&"%$)"-" An opening
song of the anime DRAGON BALL. %# Not found One of aliases of DRAGON BALL

First idea: Just using text generation AI *OTVGpDJFOUQFSGPSNBODFJOBMJBT HFOFSBUJPOʜ DRAGON
BALL DB 4FBSDI &OHJOF Search by “DB” ① ② List the aliases for the anime DRAGON BALL. (FOFSBUFUJFVQBMJBTFTVTJOHUFYU HFOFSBUJPO"*

5JFVQBMJBTFTBSFVOQSFEJDUBCMF • #PLVXB5PNPEBDIJHB4VLVOBJˠ)BHBOBJ (FOFSBUFTNBOZGBMTFUJFVQBMJBTFTBOE PWFSMPPLUJFVQBMJBTFT Why not good? 5IFUBTLSFRVJSFTOJDIFLOPXMFEHF /FFEFYUFSOBMLOPXMFEHF
)PXUPVTFJU Boku wa Tomodachi ga Sukunai Not good result… ?

Core idea &YUSBDUBMJBTFTGSPN8JLJQFEJBBSUJDMFVTJOHUFYU HFOFSBUJPO"* DRAGON BALL is Japanese manga. It
was published in 1984. It is abbreviated as “DB”. Its Story is … "OFYBNQMFBSUJDMFGPS%3"(0/#"-- 5FYUHFOFSBUJPO"* * This article defers from the actual Wikipedia article.

$PMMFDUUJFVQJOGPSNBUJPOGSPN8JLJQFEJB &YUSBDUUJFVQBMJBTFTVTJOHUFYU HFOFSBUJPO"* *OEFYUJFVQBMJBTFTBOETFBSDICZUIFN Solution: Extract from external knowledge
DRAGON BALL DB 4FBSDI &OHJOF Search by “DB” ① ② ③ Extract aliases for DRAGON BALL from following text. Text: DRAGON BALL is Japanese manga. It was published in 1984. It is abbreviated as “DB”. Its Story is …

Prompt technique: Few-shot prompting Note that you must follow these:
- Output empty if there are no tie-up aliases Example of text: ECHO-ECHO is Japanese anime. Story of Mount Fuji. Your answer: Output empty because there are no aliases. (JWFGFXTIPUFYBNQMFTJTNPSFFGGFDUJWFUIBOHJWJOHEFUBJMFEUBTL FYQMBOBUJPO * ECHO-ECHO is a fictional anime title.

Prompt technique: Chain-of-thought Output your thought before answer. Example of
text: ECHO-ECHO is Japanese anime. Story of Mount Fuji. Your answer: <thinking> Mount fuji is just object appearing in the story. </thinking> <answer></answer> -FU"*UPPVUQVUIJTIFSUIPVHIUCFGPSFBOTXFS * ECHO-ECHO is a fictional anime title.

Result and summary ⎯ 1SFDJTJPO ⎯ 3FDBMM 5FYUHFOFSBUJPO"*XJUIFYUFSOBMLOPXMFEHFIBTUIFQPUFOUJBMUPUBDLMF OJDIFUBTLT ⎯
'FXTIPUQSPNQUJOH ⎯ $IBJOPG5IPVHIU +VTUVTJOHTJNQMFQSPNQUUFDIOJRVFDBOJNQSPWFQFSGPSNBODF )JHI1SFDJTJPOBOE3FDBMMPODPMMFDUJPOPGUJFVQBMJBTFT

Conclusion ⎯ By using a non-fine-tuned model and LLM, we
were able to launch in a short period ⎯ The cancel rate decreased by 15% ⎯ Fine-tuning for a text embedding model ⎯ Other external knowledges Future work

Thank you *The song titles, anime titles and related information
mentioned in this document are used for the sake of explanation and are not associated with the respective copyright or trademark holders.

「LINE MUSIC」におけるハイブリッド検索や略称抽出を用いた曖昧検索への挑戦 / Cha...

「LINE MUSIC」におけるハイブリッド検索や略称抽出を用いた曖昧検索への挑戦 / Challenges in Ambiguous Search Using Hybrid Search and Abbreviation Extraction in "LINE MUSIC"

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