Challenges in Search in Global Services

Transcript

1. There's no way you
   wouldn't enjoy the search
   system which supports
   20+ languages
   Kentaro Takiguchi / @rejasupotaro
   1
   

   View Slide

2. Share challenges in search
   2
   

   View Slide

3. I worked in...
   4 US: 6 months
   4 Spain: 6 months
   4 Indonesia: 3 months
   4 UAE: 2 weeks
   4 Vietnam, Taiwan, Germany, Italy: 1 week
   4 UK: 1 year and 3 months ! Now
   3
   

   View Slide

4. Experienced different cultures in different countries 4
   

   View Slide

5. https://sourcediving.com/localization-at-cookpad-aa4e11498564 5
   

   View Slide

6. Discovery Team
   Providing users with the right contents at the right time
   4 Search
   4 Recommendation
   ” The difference is if explicit query is given or not
   6
   

   View Slide

7. View Slide

8. Search
   1. Index Construction
   2. Query Understanding
   3. Dictionary
   4. Scoring
   8
   

   View Slide

9. 1. Index Construction
   4 Elasticsearch = DB in search
   4 ! "Focusing on search" ≈ "Focusing on index"
   9
   

   View Slide

10. Index = Schema + Preprocessing
    4 Schema: title, country, cuisine, ingredients, ...
    4 Preprocessing:
    https://www.codeschool.com/blog/2016/03/25/machine-learning-working-with-stop-words-stemming-and-spam/ 10
    

    View Slide

11. Challenge
    The number of indices = Types * Languages
    4 !
    4 "
    n = the number of types
    m = the number of supported languages
    11
    

    View Slide

12. 2. Query Understanding
    What is query?
    4 Text
    4 Voice
    4 Image
    4 ...
    12
    

    View Slide

13. Intention = Query (+ Hidden Context)
    [User] => (Query) => [Server] => (Query + Context) => [Search Engine]
    4 Locale (! Index, Dictionary, ...)
    4 Location (! Scoring, ...)
    4 Synonyms (! Dictionary, Query, ...)
    4 Misspellings (! Language Model, Query, ...)
    13
    

    View Slide

14. "Desayuno" ! (Breakfast ")
    {
    "_source": false,
    "query": {
    "function_score": {
    "query": {
    "bool": {
    "must": [
    {
    "term": {
    "forbidden": {
    "value": false,
    "boost": 0
    }
    }
    },
    {
    "term": {
    "approved": {
    "value": true,
    "boost": 0
    }
    }
    },
    {
    "function_score": {
    "boost_mode": "replace",
    "score_mode": "sum",
    "functions": [
    {
    "filter": {
    "span_or": {
    "clauses": [
    {
    "span_term": {
    "title.raw": "desayuno"
    }
    },
    {
    "span_term": {
    "title.raw": "desayunos"
    }
    }
    ]
    }
    },
    "weight": 300
    },
    {
    "filter": {
    "simple_query_string": {
    "fields": [
    "title",
    "dish_name"
    ],
    "query": "(crep | avena | crepa | crepe | crêpe | donut | fakas | isler | lassi | mufin | yogur | churro | crepes | donuts | mafins | muffin | yogurd | yogurt | brioche | cookies | curasan | galleta | granola | maffins | muffins | mugcake | pascade | smothie | tostada | yoghurt | yogourt | yogurth | bollería | croisant | croissan | flapjack | larpeira | \"mug cake\" | porridge | smoothie | croissant | ensaimada | fritatten | frittaten | smoothies | tejeringo | frittatten | shortbread | gingerbread | \"short bread\" | \"batido verde\" | \"pan de leche\" | \"pastas de té\" | pricomigdale | \"bizcocho taza\" | \"medias noches\" | \"masa para creps\" | \"bizcocho en taza\" | \"pastas navideñas\" | \"bizcocho a la taza\" | \"hombre de jengibre\" | \"muñeco de jengibre\" | \"decoraditas vintahe\")",
    "default_operator": "AND"
    }
    },
    "weight": 100
    }
    ],
    "query": {
    "bool": {
    "must": [
    {
    "simple_query_string": {
    "fields": [
    "title",
    "dish_name"
    ],
    "query": "(crep | avena | crepa | crepe | crêpe | donut | fakas | isler | lassi | mufin | yogur | churro | crepes | donuts | mafins | muffin | yogurd | yogurt | brioche | cookies | curasan | galleta | granola | maffins | muffins | mugcake | pascade | smothie | tostada | yoghurt | yogourt | yogurth | bollería | croisant | croissan | flapjack | larpeira | \"mug cake\" | porridge | smoothie | croissant | ensaimada | fritatten | frittaten | smoothies | tejeringo | frittatten | shortbread | gingerbread | \"short bread\" | \"batido verde\" | \"pan de leche\" | \"pastas de té\" | pricomigdale | \"bizcocho taza\" | \"medias noches\" | \"masa para creps\" | \"bizcocho en taza\" | \"pastas navideñas\" | \"bizcocho a la taza\" | \"hombre de jengibre\" | \"muñeco de jengibre\" | \"decoraditas vintahe\")",
    "default_operator": "AND"
    }
    }
    ],
    "must_not": [
    {
    "simple_query_string": {
    "fields": [
    "title",
    "ingredients",
    "dish_name"
    ],
    "query": "(flan | pollo | salsa | tarta | helado | pastel | postre | salmón | ensalada | hamburguesa)",
    "default_operator": "AND"
    }
    }
    ]
    }
    }
    }
    }
    ]
    }
    },
    "functions": [
    {
    "filter": {
    "term": {
    "with_image": true
    }
    },
    "weight": 100
    },
    {
    "exp": {
    "published_at": {
    "origin": "2018-02-12T06:06:42.266Z",
    "scale": "30d",
    "decay": 0.99
    }
    },
    "weight": 1
    },
    {
    "filter": {
    "term": {
    "region_id": 1
    }
    },
    "weight": 1000.0
    }
    ],
    "score_mode": "sum",
    "boost_mode": "sum"
    }
    }
    }
    ” It's the actual Elasticsearch query. How come does it
    become so long?
    14
    

    View Slide

15. Do you understand what "Desayuno"
    is?
    It doesn't mean "the user want to see recipes which
    have Desayuno in its title" ! Query expansion
    4 Desayuno
    4 tostada, avena, galleta, crêpe, churros con
    chocolate, ...
    15
    

    View Slide

16. Challenge
    4 Knowledge of food culture is required
    4 Knowledge of language/grammer is required
    ! Spanish breakfast, Japanese breakfast" 16
    

    View Slide

17. "Query Preprocess"
    4 Cleaning
    4 Tokenization
    4 Normalization
    4 Removing stopwords
    4 ...
    17
    

    View Slide

18. Cleaning
    4 Force encode Latin-1 to UTF-8 ('tortas de
    cumpleaños' ! 'tortas de cumpleaños')
    4 "ͷ" in Taiwan
    mysql> select title from recipes where title like "%ͷ%" and provider_id = 12 order by id desc limit 3;
    +-----------------------------------------------------------+
    | title |
    +-----------------------------------------------------------+
    | ຑ᫤∍໦ࣖྋ፩ࢁᠴਯɽᐬᇯᇯͷ২෺ԏᜰ |
    | ؔ੢෩ͷᆹتᗑ |
    | ὑѼͷਗ਼ྋҰՆ ♥ ྉཧ ✿ ᫊ᱷ༻ిುࣽ“→౾౬” |
    +-----------------------------------------------------------+
    3 rows in set (0.24 sec)
    18
    

    View Slide

19. View Slide

20. Diacritical Marks in Vietnamese
    https://ja.wikipedia.org/wiki/%E3%83%99%E3%83%88%E3%83%8A%E3%83%A0%E8%AA%9E 20
    

    View Slide

21. View Slide

22. Tokenization
    1. Simple Tokenizer
    2. Ngram Tokenizer
    3. Language Dependent Tokenizer
    22
    

    View Slide

23. 1. Simple Tokenizer
    4 "Cheese Cake" ! "Cheese", "Cake"
    4 "Water/Salt" ! "Water", "Salt"
    23
    

    View Slide

24. 2. Ngram Tokenizer
    24
    

    View Slide

25. 2. Ngram Tokenizer
    "Donaudampfschiffahrtselektrizitätenhauptbetriebsw
    erkbauunterbeamtengesellschaft"
    υφ΢ؿધిؾࣄۀຊ޻৔޻ࣄ෦໳Լڃ׭ལ૊߹ 25
    

    View Slide

26. View Slide

27. 3. Language Dependent Tokenizer
    4 "ࢲ͸ਓࢀΛ1ຊ͚ͩങͬͨ"
    4 "ࢲ", "͸", "ਓࢀ", "Λ", "1", "ຊ", "͚ͩ", "ങͬ", "ͨ"
    27
    

    View Slide

28. Negation Handling
    4 en:"without", "no", "with no"
    4 es: "sin"
    4 id: "tanpa", "no"
    4 vi: "không cần dùng", "không cần", "không dùng",
    "không"
    4 ar: " د
    و
    ن
    "
    ,
    "
    ب
    د
    و
    ن
    "
    ,
    "
    م
    ن
    د
    و
    ن
    "
    ,
    "
    م
    ن
    غ
    ي
    ر
    "
    ,
    "
    ب
    ال "
    28
    

    View Slide

29. Normalization: Misspellings
    Which is the correct spelling?
    1. brocoli
    2. brocolli
    3. broccoli
    4. broccolli
    5. brroccolli
    29
    

    View Slide

30. Normalization: Spelling Correction
    Affix File + Custom Dictionary File for !
    TRY esiaénrtolcdugmfphbyvkw-'.zqjxSNRTLCGDMFPHBEAUYOIVKWóöâôZQJXÅçèîêàïüäñ
    NOSUGGEST !
    COMPOUNDMIN 1
    ONLYINCOMPOUND _
    COMPOUNDRULE 2
    COMPOUNDRULE #*0{
    COMPOUNDRULE #*@}
    WORDCHARS 0123456789’
    REP 27
    REP f ph
    REP ph f
    PFX A Y 2
    PFX A 0 re [^e]
    ...)
    30
    

    View Slide

31. Normalization: Spelling Correction
    Affix File + Custom Dictionary File for !
    Aachen/M
    aardvark/MS
    aardwolf
    aardwolves
    aargh
    Aarhus/M
    Aaron/M
    Aaronvitch/M
    ab
    Ababa/M
    aback
    abacus/SM
    ...
    31
    

    View Slide

32. View Slide

33. Normalization: Spelling Correction
    Autoencoder: Query + Noise which simulates human misspellings
    ☑ protyein => protein
    ☑ chorrilltana => chorrillana
    ☑ obusuuma => obusuma
    ☑ noirdic => nordic
    ☑ midwlestern => midwestern
    ☑ fklower => flower
    ☑ gtoast => toast
    ☑ byat => bat
    ☑ yoogurt => yogurt
    ☑ lgrill => grill
    ☑ romsanian => romanian
    ☑ bulgaroia => bulgaria
    ☑ bzarbecue => barbecue
    ☑ krombu => kombu
    ☑ wwine => wine
    ☑ icelanldic => icelandic
    ...
    33
    

    View Slide

34. Normalization
    "cheesecakes" => "cheesecake"
    "cheescake" => "cheesecake"
    "tarta de queso" => "cheesecake"
    "tarta de quesos" => "cheesecake"
    "tartas de queso => "cheesecake"
    "tartas de quesos" => "cheesecake"
    34
    

    View Slide

35. View Slide

36. 3. Dictionary
    = Stored Domain Knowledge
    4 Categories (Cuisine, Event, Occastion, ...)
    4 Types (Dish, Ingredient, Tool, ...)
    4 Parent-child relationships
    4 Synonyms
    4 Negatives
    36
    

    View Slide

37. Challenge
    Dictonaries are prepared not only by language, by
    region
    37
    

    View Slide

38. Synonyms
    e.g. weenie
    38
    

    View Slide

39. Knowledge... depends on the indivisual
    4 What if the dictionary maintainer is good at cooking
    seafood but not good at making sweets?
    39
    

    View Slide

40. Ontology (Knowledge Graph)
    40
    

    View Slide

41. Synonyms
    Dictionary Tool => SPARQL => Ontology
    SELECT $redirectsTo
    WHERE {
    FILTER (?uri = dbr:#{word})
    ?redirectsTo dbo:wikiPageRedirects ?uri .
    }
    => Chili, Chili Pepper, Red Chili, Hot Pepper, ...
    41
    

    View Slide

42. Synonyms
    Needs to be specialized in Cooking
    issue word example of retrieved result
    irrelevant to cooking dinner the dinner (chinema)
    not useful for search mexican united states of mexico
    child included 1 chicken chicken leg
    child included 2 donburi ikuradon
    a bit (?) different donburi tenshin-han
    42
    

    View Slide

43. Misspellin... Synonyms?
    siomay, somay, sio may, shomay, shumai, shumay,
    syomay, siomai, ...
    43
    

    View Slide

44. Synonyms
    How about word embeddings?
    "tortilla" is similar to...
    ('tortillas', 0.9796085953712463)
    ('enchiladas', 0.977012574672699)
    ('enchilada', 0.9445205926895142)
    ('taco', 0.9363764524459839)
    ('pepperoni', 0.9355688095092773)
    ('doritos', 0.9267387390136719)
    ('burritos', 0.9246858954429626)
    ('jack', 0.9222062230110168)
    ('burrito', 0.919107973575592)
    44
    

    View Slide

45. Negatives
    e.g. $Picnic\ Shoulder \notin Picnic$
    45
    

    View Slide

46. 4. Scoring
    46
    

    View Slide

47. What users want to see varies by region 47
    

    View Slide

48. Recommendation
    4 Provide recipes without an explicit query (Query +
    Context)
    4 What the user tend to like/cook
    4 Taste preferences
    4 Available ingredients
    4 For what? Breakfast? Lunch? Dinner? Party?
    48
    

    View Slide

49. Each market has different features
    4 Number of recipes
    4 Matured Markets >>>>> New Markets
    4 Priority
    4 Available data/logs
    4 Quality of product
    49
    

    View Slide

50. Understand
    Users ❤ Recipes
    50
    

    View Slide

51. A lot of challenges
    4 Knowledge of Food
    4 Locality (languages, traditions, religions, …)
    4 Linguistics Issues
    4 How to build/store knowledge
    4 We ❤ Machine Learning
    51
    

    View Slide

52. We are hiring!
    4 ! https://info.cookpad.com/en/careers
    4 " https://info.cookpad.com/careers
    52
    

    View Slide