August 2012 Daejeon, South Korea

Transcription

1 Building a Web of Linked Entities (Part I: Overview) Pablo N. Mendes Free University of Berlin August 2012 Daejeon, South Korea

2 Outline Part I A Web of Linked Entities Challenges Progress towards solutions Opportunities (Project Ideas) Part II Technical description of phrase recognition / entity linking Practical considerations for your project implementation

3 The (Shallow) Web Interlinked (mostly textual) documents Targeted for human consumption Information seeking search engines match keywords human sifts through documents (search-and-sift)

4 The Deep (Hidden) Web Databases are used behind the scenes From the outside, it looks just like the shallow Web Despite the presence of the DB, still search-a The Web DB Intranet

5

6 Slide adapted from Christian Bizer The Web, traditionally

7 The Web of Linked Data The deep, explicit, shared, linked Web Databases reference each other directly Entities have Web addresses Documents Linked Data DB DB DB DB DB DB DB The Web Intranet

8 The Web of Linked Data Information seeking starts to shift towards querying All soccer players, who played as goalkeeper for a club that has a stadium with more tha Allows for connecting pieces of answers coming from different databases

9 Embedding Structured Data on the Web of Documents The Web Microdata Intranet Ways to describe meaning of what's inside the Connects content of the to data So far, emphasis on schema

10 Embedding descriptions in HTML RDFa Microdata

11 Schema.org Google, Yahoo!, Microsoft Site owners to embed structure 200+ types: event, organization Encoding: microdata, RDFa

12

13 Embedded Structured Data Helps search engines find and understand content... directly and indirectly (by example)

14 The Web of Linked Entities Text is explicitly linked to structured data DB Ultimately we want to use the entire Web like a global database (documents too!) DB DB DB

15 Wikipedia and DBpedia A prototypical Web of Linked Entities DBpedia provides Linked Data extracted from Wikipedia Wikipedia contains text about DBpedia entities Manually created information Cross-domain (Geographic, Sports, Science,...) Multi-language (111 languages) Focus on notable entities

16 Challenges For that, we need ways to interconnect documents and databases Even for documents that were not generated from databases We need to do that automatically At least semi-automatically But how can we do that? Many solutions I will describe our approach

17 A Virtuous Cycle

18 What is DBpedia Spotlight? Annotates text with links to LOD via DBpedia Things are uniquely identified by DBpedia URIs Learns from text in Wikipedia

19 What is DBpedia Spotlight? Annotates text with links to LOD via DBpedia Recognizes entities (Person, Location, Organization) Politician, Automobile, Movie, Flowering Plant,etc. or any other 360 classes in DBpedia

20 What is DBpedia Spotlight? Annotates text with links to LOD via DBpedia Recognizes entities (Person, Location, Organization) Also links entity mentions to unique identifiers Michael Jordan (professor), Michael Jordan (basketball player) or any other 3.8M things in DBpedia

21 A quick example

22 Annotate s

23 Annotate s 4 (album)

24 Top K Candidates LSU_Tigers Louisiana State University

25 DBpedia Spotlight Demo: Web Service: APIs: Phrase Recognition (/spot), Disambiguation (/disambiguation) Top K disambiguations (/candidates) Annotation (/annotation) Source code: Apache V2 License!

26 A Virtuous Cycle

27 Sztakipedia Developed by Mihály Héder et al. at MTA SZTAKI (Hungarian Academy of Sciences) Adds a toolbar to Wikipedia that can use DBpedia Spotlight to suggest links Also suggests Categories, Infoboxes, Books Helps editors to refine knowledge in Wikipedia More interconnections, more entity types, more structured data!

28 Sztakipedia (screenshots) Source: v=8vw0trvxpl4

29 Beyond Wikipedia, perhaps? Wikipedia doesn't have everything. You promised a Web! Another database besides DBpedia? Other text besides Wikipedia? Tons! Just look at the LOD cloud. Text?

30 Virtous Cycle beyond Wikipedia? RDFaCE Developed by Ali Khalili at U. Leipzig (AKSW) Helps users to add RDFa markup via a WYSIWYG interface

31 Virtous Cycle beyond Wikipedia? RDFaCE Can use DBpedia Spotlight, among other services to recognize/disambiguate entity names

32 RDFaCE Available as a Wordpress Plugin Enables blogs as sources of context for disambiguation RDFa markup can be used: to build a global graph to train systems like DBpedia Spotlight

33 Google Knowledge Graph Commercial (curated) and automatically extracted data 500 million objects 3.5 billion facts (attributes and relationships) Well interconnected: 1.5 relationships / 1 attribute Closed access. No API.

34 Open Knowledge Graph Crowd sourcing approach to open up access to closed Knowledge Graphs Uses browser extension to scrape SERP and update server terms (schema) mapped to LOD vocabularies Permanent work in progress

35 Project Ideas Open Knowledge Graph Annotator A quick wrapper around DBpedia Spotlight Facetnator A fascinating automatic facet detector and browser rel8.dbpedia.org Semantic relatedness for DBpedia

36 Project Idea: Facetnator Imagine you have a list of documents (e.g. news articles) Can we automatically organize them by topic, by person mentioned, etc.? Can we use DBpedia Spotlight to help with that?

37 Project Idea: rel8.dbpedia.org New endpoint for querying DBpedia data Given one URI, provides a list of other related URIs based on DBpedia Spotlight's definition of Similar contexts Same type Link to the same entities Under same category Can give a score between two URIs

38 Semantic Web Challenge? Friday October 12, 2012, 23:59 CET: Submissions due November 13-15: Semantic Web Challenge takes place at ISWC 2012

39 Conclusion A Web of Linked Entities is on the make Both structured and unstructured data are needed Connecting structured and unstructured data provides a virtuous cycle of benefits

40 What's next Part II: Building a Web of Linked Entities More technical descriptions How do we obtain and use prior, contextual and cohesion scores How to build a tool for linking text to databases Can you use DBpedia Spotlight beyond DBpedia?

41 Thank you. Questions? Web: