schema.org, Wikidata, Knowledge Graph:

strands of the modern semantic web

Dan Scott, Laurentian University
coffeecode.net / +Dan Scott / @denials

Knowledge graph IDs in the middle
Wikidata IDs and relations at the edges
schema.org data as bugs (raw material for the semantic web)

Laziness

The virtue is about the avoidance of future work.

Virtues of the Perl Programmer, Larry Wall

Linked open data aspires to be lazy

Publish and let the data be consumed
Avoid the hard work natural of language parsing / entity recognition and disambiguation
Pull the data you need from various aggregators

Who is the governor of Ohio?

Knowledge Graph sources

Freebase
Wikipedia / Wikidata
Crawling the web
Licensed data

Freebase: Open graph database launched in 2007

Focused on entities and relationships

Each type of entity was well-structured

with browsable instances

Freely available with a great auto-suggest API
Purchased by Google in 2010
... sunset August 31, 2016

Knowledge Graph Search API

Google taketh away but also giveth: https://developers.google.com/knowledge-graph/

Enable the API in the Google API Console
Daily quota of 100,000 requests, 17,000 "Discovery" requests
Undocumented result limit of 200; defaults to 20

Knowledge Graph Discovery Widget


  
  
  


  
    Search:

Awesome live demo!

KG Search API: Requests

Same general constraints (type, limit) as the widget
- https://kgsearch.googleapis.com/v1/entities:search?key=$API_KEY&query=john+kasich
Can also request specific KG IDs:
- https://kgsearch.googleapis.com/v1/entities:search?key=$API_KEY&ids=/m/02zzm_

KG Search API: Results

{ "@context": {
    "@vocab": "http://schema.org/",
    "goog": "http://schema.googleapis.com/",
    "EntitySearchResult": "goog:EntitySearchResult",
    "detailedDescription": "goog:detailedDescription",
    "resultScore": "goog:resultScore",
    "kg": "http://g.co/kg"
  },
  "@type": "ItemList", "itemListElement": [
    {
      "@type": "EntitySearchResult",
      "result": {
        "@id": "kg:/m/02zzm_",
        "name": "John Kasich",
        "@type": [ "Person", "Thing" ],
        "description": "Governor of Ohio",
        "image": {
          "contentUrl": "http://t1.gstatic.com/images?q=tbn:ANd9GcRoou4pZKD6FoNaE71ngNlv4RGgUS46mgtin5YJtyEoh42CIs4x",
          "url": "https://en.wikipedia.org/wiki/John_Kasich"
        },
        "detailedDescription": {
          "articleBody": "John Richard Kasich is an American politician, the 69th and current Governor of Ohio. First elected in 2010 and re-elected in 2014, Kasich is a member of the Republican Party. His term is set to end by January 2019.\n",
          "url": "https://en.wikipedia.org/wiki/John_Kasich",
          "license": "https://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License"
        },
        "url": "https://johnkasich.com"
      },
      "resultScore": 22.28808
    }
  ]
}

Knowledge Graph IDs

"kg": "http://g.co/kg"
...
"@id": "kg:/m/02zzm_"

So: http://g.co/kg/m/02zzm_

URIs don't have to resolve, but it's nice when they do!

Knowledge Graph API problems

Limited constraints = poor precision
- Can't limit to name of the entity
Type mapping to schema.org loses more precision
- A Fictional character is a Thing, not Person
Simplistic entity results: no facts, no relationships
- When was John Kasich born? - no birthdate returned

Search cannot be constrained to just the name of the entity, so "Buffy" returns references found anywhere in the description of the entity

Compounded by having to use https://schema.org/Thing for many old Freeweb types like "Fictional Universe" or "Fictional Character" -- "Person" filters out fictional characters, so books / tv shows / actors who played the role show up

The results contain only disconnected entities; none of the relationships to other entities in the graph are reflected in the results. Many of the properties used in Google's results are missing (e.g. birth date)

The Graph is a lie!

One could download the 250GB Freebase data dump and reconstruct the relationships based on the IDs (most of the KG IDs were inherited from Freebase), but that data is now rapidly aging. Who's the President-Elect now?

Knowledge Graph: entity relations

Note: The Knowledge Graph Search API returns only individual matching entities, rather than graphs of interconnected entities. If you need the latter, we recommend using data dumps from Wikidata instead.

https://developers.google.com/knowledge-graph/

Wikidata

Wikidata entity search

REST-based MediaWiki API wbsearchentities module:

https://www.wikidata.org/w/api.php?action=wbsearchentities&search=john+kasich&language=en

Restrictions: Serial requests, or risk the ban hammer!

wbsearchentities results

{
  "searchinfo": { "search": "john kasich" },
  "search": [
    {
      "id": "Q69319",
      "concepturi": "http://www.wikidata.org/entity/Q69319",
      "url": "//www.wikidata.org/wiki/Q69319",
      "title": "Q69319",
      "pageid": 72036,
      "label": "John Kasich",
      "description": "American politician",
      "match": {
        "type": "label",
        "language": "en",
        "text": "John Kasich"
      }
    }
  ]
}

Human: http://www.wikidata.org/entity/Q69319

JSON: http://www.wikidata.org/entity/Q69319.json

Relationships

With https://www.wikidata.org/entity/ as prefix wde:, the entity wde:Q69319 ("John Kasich"):

has the property wde:P569 (was born) with the literal value "+1952-05-13T00:00:00Z";

also has the property wde:P39 ("positions held")
with the array member wde:Q13218630 ("United States representative")
having the property wde:P580 ("start time")
with the literal datavalue/value/time value of +1983-01-03T00:00:00Z.

Graph Relationships

More simply...

Subject	Predicate	Object
wde:Q69319	wde:P569	"+1952-05-13T00:00:00Z"
wde:Q69319	wde:P39	wde:Q13218630
wde:Q13218630	wde:P580	"+1983-01-03T00:00:00Z"

SPARQL endpoint

SPARQL is the primary and most powerful query interface for Wikidata
And it's a standard: yay!
SELECT / WHERE / GROUP BY / ORDER... just like SQL right?
Ish - querying a graph instead of a relational database

SPARQL examples

We can pull some awesome results from Wikidata:

SPARQL endpoint

URL: https://query.wikidata.org/sparql?query=
30-second timeout

Available formats:

Format	HTTP Header	GET param
XML	Accept: application/sparql-results+xml	format=xml
JSON	Accept: application/sparql-results+json	format=json
TSV	Accept: text/tab-separated-values
CSV	Accept: text/csv

Getting data into Wikidata

Manual edits
Bulk loading (with agreement)--like Freebase!
APIs and bots:
- wbcreateclaim to add new claims
- wbeditentity to add entities

Notability requirements still apply

A typical four-year old?

Not just cute anymore
Still growing rapidly: 25 milion entities
A little unstable: queries can and do break
Will benefit from guidance

schema.org

Decentralized data publishing

Introducing modal news!

OpenGraph Protocol


  LIVE REVIEW: Midpoint Music Festival — Cincinnati, OH – The Owl Mag – Medium

Twitter Cards


  LIVE REVIEW: Midpoint Music Festival — Cincinnati, OH – The Owl Mag – Medium

schema.org

schema.org (inline RDFa)


  LIVE REVIEW: Midpoint Music Festival — Cincinnati, OH
  
    Published by
    
      
        The Owl Mag
      
    
    2011-09-27
  
  
  Cincinnati is not a music city by any means. Numerous bands skip the city in lieu of Columbus, OH on national tours and the city’s hottest music venues reside over the river in Kentucky. Midpoint...

Deep, rich structrure

584 types, 846 properties
Covering a broad set of domains:
- commerce
- culture
- events
- health
- organizations
Run as a W3C Community Group
Extensible

Impatience (virtue #2)

Joined the Bibliographic Extension community
- Fleshed out journals/magazines
- Represented library holdings as Product/Offers
- Dragged comics across the finish line
Implemented schema.org support in library systems
Evangelized schema.org at conferences and articles
Aggregated library linked open data for analysis and reuse

Hubris (virtue #3)

Through my DIALLED.ca project, I checked over 4,000 library home pages in Canada
525 had OpenGraph Protocol title attributes
215 had schema.org/name attributes
10 had Twitter Cards
5 used schema.org/Library

Result: Despair (a bit)

Adoption from 2014 to 2015

Big data makes common schemas even more necessary.
[...]
In this sample 31.3 percent of pages have Schema.org markup, up from 22 percent one year ago.

Guha, R. V., Brickley, D., & Macbeth, S. (2016). Schema.org: Evolution of structured data on the web. Communications of the ACM, 59(2), 44-51. (http://cacm.acm.org/magazines/2016/2/197422-schema-org/fulltext)

The semantic web is alive

schema.org data is very rich in some communities
Crawling and aggregating schema.org data can make sense
That can feed into wikidata
We can pull from and build on top of wikidata
That can also feed the Google Knowledge Graph
EVERYTHING GETS BETTER

Questions?

Please direct them to ~~my SPARQL endpoint~~ the microphone
Slides: coffeecode.net/ohiodevfest16
Social: @denials / +DanScottCAN
Blog: coffeecode.net

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License