YAGO – A Core of Semantic Knowledge

YAGO - A Core of Semantic Knowledge 1Fabian M. Suchanek

YAGO – A Core of Semantic Knowledge

Fabian M. Suchanek, Gjergji Kasneci, Gerhard Weikum

(Max-Planck Institute for Computer Science Saarbrücken/Germany)


Overview

Motivation ر

The Yago ontology ر

Content ر

Model ر

Extension ر

Conclusion ر


The Truth about Elvis

Elvis is alive!



Elvis is alive!

He works as an astronaut in

NASA's special security program


Usual solution

Which NASA astronaut was born when Elvis was born?

Yields only rubbish.

Reasons:

1. Google participates in the conspiracy

2. Google does not search knowledge, but Web sites


Solution: An ontology

born1935 ?born

is anastronaut



born1935 ?born

is aastronaut

person

entity

subclass

subclass

"Elvis Presley" "The King"

means means

is a



born1935 ?born

is aastronaut

person

entity

subclass

subclass

"Elvis Presley" "The King"

means means

Words

is a

Individuals

Classes

Relations


Where do we get the ontology from?

Previous approaches:

Assemble the ontology manually ر

(WordNet, SUMO, GeneOntology)

Problems: Usually low coverage (MPI is in none of these)

Extract the ontology from corpora (e.g. the Web) ر

(KnowItAll, Espresso, Snowball, LEILA)

Problem: Usually low accuracy (50%-92%)


Where do we get the ontology from?

YAGO approach:

Assemble the ontology from Wikipedia (=> good coverage)

Use the category system of Wikipedia (=> good accuracy)


Exploiting the Wikipedia category system

Elvis Pr

blah blah blub Elvis (don't read this! Better listen to the talk!) laber fasel suelz. Insbesondere, blub, texte zu, und so weiter blah blah blub Elvis laber fasel suelz. Blub, aber blah! Insbesondere, blub, texte zu, und so weiter blah blah blub Elvis laber fasel suelz. Insbesondere, blub, texte zu, und so weiter

Categories:

1935_births

1935born

Exploit relational categories



Elvis Pr


Categories:

American_singers

1935born

Exploit relational categoriesExploit conceptual categories

American_singer

is a



Elvis Pr


Categories:

Disputed_articles

1935born


American_singer

is ais a

Disputed_article

Avoid administrational categories



Elvis Pr


Categories:

Rock'n_Roll_Music

1935born


American_singer

is ais a

Rock'n_Roll_Music

Avoid administrational categoriesAvoid thematic categories


The Upper Model

1935born

American_singer

is a

person

entity

?


The Upper Model: From Wikipedia?

1935born

American_singer

is a

People_by_occupation

Business

?Social_group


The Upper Model: From WordNet?

1935born

American_singer

is a

Singer#1

Person#3

Singer#17...


The Upper Model: From WordNet?

1935born

American_singers_of_Jewish_origin

is a

Singer#1

Person#3

Singer#17...Origin#7


The YAGO ontology

1935born

American_singer

is a

Singer#1

Person#3

subclass

subclass

"singer"

means

"Elvis Presley"means


The YAGO ontology: Accuracy

Relation Accuracysubclass 97.70% +/- 1.59%is a 94.54% +/- 2.36%familyName 97.81% +/- 1.75%givenName 97.62% +/- 2.08%establishedIn 90.84% +/- 4.28%bornInYear 93.14% +/- 3.71% diedInYear 98.72% +/- 1.30% locatedIn 98.41% +/- 1.52%politicianOf 92.43% +/- 3.93%

writtenInYear 94.35% +/- 3.33%hasWonPrize 98.47% +/- 1.57%


The YAGO ontology: Number of Facts

KnowItAll SUMO WordNet OpenCyc Cyc

30,000 60,000 200,000 300,000

2,000,000

6,000,000

Yago

Ontologies should not be judged purely by the number of facts! This is just an informational overview.


The Yago Model: Why binary is not enough

singer

is a

(But only from 1953 to 1977)

(We know this from Wikipedia)

(Elvis, is_a, singer)


The Yago Model: Why binary is not enough

is a

1953-1977

Wikipedia

time

source

#1 (Elvis, is_a, singer)

#2 (#1, time, 1953-1977)

#3 (#1, source, Wikipedia)

singer


The Yago model formally

A YAGO ontology over

a set of relations R رa set of common entities C رa set of fact identifiers I رis a function

I (RCI) R (RIC)

#1 (Elvis, is_a, singer)

#2 (#1, time, 1953-1977)

#3 (#1, source, Wikipedia)

We can talk aboutfacts (#1, source, Wikipedia) رadditional arguments (#1, time, 1953-1977) رrelations (time, hasRange, time_interval) ر


The Yago model: Logical aspects

Axioms:

(x, is_a, y)

(y, subclass, z)

=> (x, is_a, z)

...

singer

person

subclass

is a

is a


The Yago model: Logical aspects

Axioms:

(x, is_a, y)

(y, subclass, z)

=> (x, is_a, z)

...f1, f2, f3, f4, f5

f1, f2, f3

f1, f2, f3, f4, f5, f6, f7, f8, f9, f10

derive facts

Eliminate facts

finite, unique

finite, unique


Extending the Ontology

Whom did Elvis marry?

Elvis married Priscilla

X married Y

Priscilla



Whom did Elvis marry?X married Y

subj obj

Elvis, the great rock star, married Priscilla

subj obj

Priscilla

with LEILA



Ontology

(YAGO)

Information Extraction

(LEILA)



http://www.mpi-inf.mpg.de/~suchanek/downloads/yago/

"Elvis Presley" bornInYear $year

$astro bornInYear $year

$astro isa astronaut

Enter your Yago Query:

Which astronaut was born in the same year as Elvis?

20 results





"Elvis Presley" bornInYear $year

$astro bornInYear $year

"Roger" givenNameOf $astro

$astro isa astronaut

Enter your Yago Query:

Which astronaut codenamed "Roger" was born in the same year as Elvis?

$astro = Roger_Chaffee



Conclusions

Yago bases on a logically clean model ر

Yago has an accuracy of around 95% ر

Yago is 3 times larger than the largest competitor ر

Elvis is alive ر


Reference

For all details, please refer to our technical report

"Yago – A Core of Semantic Knowledge"

(Fabian M. Suchanek, Gjergji Kasneci, Gerhard Weikum)

available at http://www.mpii.mpg.de/~suchanek

BibTex:@TECHREPORT{yagotr, AUTHOR = {Suchanek, Fabian and Kasneci, Gjergji and Weikum, Gerhard}, TITLE = {Yago: A Core of Semantic Knowledge}, TYPE = {Research Report}, INSTITUTION = {Max-Planck-Institut f{\"u}r Informatik}, ADDRESS = {Stuhlsatzenhausweg 85, 66123 Saarbr{\"u}cken, Germany}, NUMBER = {MPI-I-2006-5-006}, YEAR = {2006}}

http://www.mpii.mpg.de/~suchanek

YAGO – A Core of Semantic Knowledge

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