Information Retrieval (SS 2011)

Transcription

7. Seman)sche(re) Suche
Rückblick
✦
World Wide Web – dezentralisiert organisierter Hypertext
✦
Crawler sammeln dezentralisiert gespeicherte Web-‐Inhalte
✦
Duplikate und Beinahe-‐Duplikate müssen eliminiert werden
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Link-‐Analyse für besseres Ranking miJels Web-‐Graph
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Lernbasiertes Ranking kombinieren verschiedene Merkmale
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Web-‐Archive – vergangene Web-‐Inhalte als Kulturerbe
✦
Sponsored Search – Haupteinnahmequelle von Google & Co
Informa)on Retrieval (SS 2011)
2
Mo)va)on
The Semantic Web is not a separate Web but an extension of the current one, in which information is given well-‐de<ined meaning, better enabling computers and people to work in cooperation
[Tim Berners-Lee]
✦
World Wide Web ist für Computer nicht interpre?erbar – Suchmaschinen chancenlos für Informa)onsbedürfnisse wie
Zahnarzt in Marburg mit Sprechstunde bis 19.00 Uhr am Donnerstag
Filme in denen Ben Affleck Regie geführt und selbst mitgespielt hat
Welche Politiker haben Spenden von Energieunternehmen im
Wahlkampf erhalten und gegen einen Atomausstieg gestimmt?
3
Inhalt
(1) Seman)c Web
(2) URIs und RDF
(3) Ontologien und Wissensbasen
(4) SPARQL
4
7.1 Seman?c Web
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✦
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Seman?c Web ist eine Ergänzung des World Wide Webs mit dem Ziel Inhalte für Computer interpre?erbar zu machen
Inhalte aus verschiedenen Quellen können damit automa?sch verknüpG und neue Zusammenhänge entdeckt werden
Berners-‐Lee et al. [3] beschreiben Vision des Seman)c Web bereits im Jahr 2001; breite Anwendung der vorgestellten Ideen jedoch erst in den letzten ca. 5 Jahren
5
Seman)c Web
World Wide Web Consor?um (W3C) definiert Standards
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✦
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zur eindeu)gen Iden)fizierung von Ressourcen (URIs)
zur Beschreibung der Eigenschahen von Ressourcen (RDF)
zur Beschreibung von Schemata (RDF/S)
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zur Beschreibung von Ontologien (OWL)
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zum Formulieren von Anfragen (SPARQL)
Seman?c Web Stack
6
7.2 URIs und RDF
✦
Unified Resource Iden?fier (URI) ist eine ZeichenkeJe zur Iden?fika?on einer abstrakten oder physischen Ressource
http://www.bbc.co.uk/music/artists/67f66c07-6e61-4026-ade5-7e782fad3a5d
http://en.wikipedia.org/wiki/Foo_Fighters
http://www.musicbrainz.org/artist/67f66c07-6e61-4026-ade5-7e782fad3a5d
✦
Ein URI verweist auf genau eine Ressource
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Ressource kann von mehreren URIs referenziert werden
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Unified Resource Iden)fier
http://www.host.org/pub/bands?query=FF#albums
Bestandteile eines Uniform Resource Iden)fiers sind
✦
✦
✦
✦
✦
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Scheme (z.B. hJp, urn, hp) bes)mmt Art des URI und
seine Interpreta)on
Authority (z.B. Name eines Hosts) gibt Instanz an, die für Verwaltung der Namen in diesem Raum zuständig ist
Path enthält hierarchische Angaben zur Iden)fizierung einer Ressource
Query enthält nicht hierarchische Angaben zur Iden)fizierung einer Ressource
Fragment referenziert einen Teil innerhalb einer Ressource
8
Resource Descrip)on Framework
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Resource Descrip)on Framework (RDF) ist Daten-‐Modell zur
formalen Repräsenta?on von Informa?onen über Ressourcen
RDF-‐Ausdruck (RDF statement) ist ein (S,P,O)-‐Tripel bestehend aus Subjekt, Prädikat und Objekt, welche jeweils URIs sind
Beispiel: Foo Fighters haben Bandmitglied Dave Grohl
http://dbtune.org/musicbrainz/page/artist/67f66c07-6e61-4026-ade5-7e782fad3a5d (S)
http://xmlns.com/foaf/spec/20100809.html#member (P)
http://dbtune.org/musicbrainz/page/artist/4d5f891d-9bce-45ae-ad86-912dd27252fa (O)
Subjekt
Prädikat
Objekt
9
✦
Eine Menge von RDF-‐Tripeln ergibt einen RDF-‐Graphen
a:playsOn
a:ma
ke
a:m
✦
e
ak
r
r Of
Of
ber
m
e
a:m
a:m
em
be
r
Namespaces repräsen)eren (häufig verwendete) Präfixe von URIs und erlauben eine kompaktere Nota)on
@prefix a: http://allaboutmusic.org/
10
✦
RDF/N3 als Text-‐Format zur Darstellung von RDF-‐Daten
@ prefix
a:
a:Foo_Fighters
a:Foo_Fighters
✦
http://allaboutmusic.org
a:member
a:member
a:Dave_Grohl
a:Pat_Smear
RDF/XML als XML-‐Format zur Darstellung von RDF-‐Daten
<?xml version=”1.0”>
<rdf:RDF
xmlns:rdf=”http://www.w3.org/1999/02/22-rdf-syntax-ns#”
xmlns:a=”http://allaboutmusic.org/”>
<rdf:Description rdf:about=”http://allaboutmusic.org/Foo_Fighters”>
<a:member rdf:resource=”http://allaboutmusic.org/Dave_Grohl” />
<a:member rdf:resource=”http://allaboutmusic.org/Pat_Smear” />
</rdf:Description>
</rdf:RDF>
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7.3 Ontologien und Wissensdatenbanken
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✦
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Taxonomie (taxonomy) beschreibt bestehende Klassen und deren subclass/superclass-‐Rela)onen zueinander
Ontologie (ontology) beschreibt zusätzlich beliebige Rela)onen zwischen Klassen
Wissensdatenbank (knowledge base) beschreibt zusätzlich Instanzen sowie Fakten über diese Instanzen
entity
organization
person
musical organization
artist
subclassOf
12
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✦
✦
entity
organization
person
artist
subclassOf
hasMember
12
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✦
✦
entity
organization
person
artist
Dave_Grohl
Foo_Fighters
Pat_Smear
subclassOf
hasMember
type
12
Ontologien und Wissensdatenbanken
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Das Gebiet der Künstlichen Intelligenz hat sich schon lange vor dem Seman)c Web mit Ontologien, Wissensdatenbanken und anderen Methoden der Wissensrepräsenta?on befasst
Ontologien manuell zu erstellen ist ein aufwendiger Prozess, so dass Ontologien in der Vergangenheit sehr klein waren bzw. nur einen bes?mmtes Gebiet (z.B. Archäologie) abdeckten
Eine Reihe von Projekten hat in den letzten Jahren Verfahren zur Informa?onsextrak?on auf Wikipedia und andere Datenquellen angewendet, um daraus automa?sch umfassende Wissensdatenbanken abzuleiten
13
DBpedia
✦
✦
http://dbpedia.org
3.5 Millionen En))es / 670 Millionen Fakten
About: Foo Fighters
An Entity of Type : Band, from Named Graph : http://dbpedia.org, within Data Space : dbpedia.org
Foo Fighters are an American alternative rock band from Seattle, Washington, formed in 1995. Drummer Dave Grohl formed the group as a one-man
project after the dissolution of his previous band, Nirvana, in 1994. Prior to the release of the band's eponymous debut album in 1995, Grohl drafted
two members from the former band Sunny Day Real Estate, Nate Mendel as bassist, and William Goldsmith as drummer, as well as fellow Nirvana
bandmate Pat Smear as guitarist to complete the group.
Property
dbpedia-owl:abstract
Value
Foo Fighters ist eine US-amerikanische Rockband. Prominentestes Mitglied ist der ehemalige NirvanaSchlagzeuger Dave Grohl.
Foo Fighters are an American alternative rock band from Seattle, Washington, formed in 1995. Drummer Dave
Grohl formed the group as a one-man project after the dissolution of his previous band, Nirvana, in 1994. Prior
to the release of the band's eponymous debut album in 1995, Grohl drafted two members from the former band
Sunny Day Real Estate, Nate Mendel as bassist, and William Goldsmith as drummer, as well as fellow Nirvana
bandmate Pat Smear as guitarist to complete the group. The band was small, young, and began with
performances in Portland, Oregon before gaining popularity. Goldsmith left during the recording of the group's
second album, The Colour and the Shape (1997), and Smear's departure followed soon afterward. They were
replaced by Taylor Hawkins and Franz Stahl, respectively, although Stahl left prior to the recording of the
group's third album, There Is Nothing Left to Lose (1999). Chris Shiflett joined as the band's third guitarist after
the completion of There Is Nothing Left to Lose. The band released its fourth album, One by One, in 2002. The
group followed that release with the two-disc In Your Honor (2005), which was split between acoustic songs
and harder-rocking material. Foo Fighters released its sixth album, Echoes, Silence, Patience & Grace, in 2007.
Later that year, guitarist Pat Smear rejoined the band. Over the course of the band's existence, three of its
albums have won Grammy Awards for Best Rock Album, and all six have been nominated for Grammys.
Foo Fighters es una banda de origen estadounidense creada en el año 1995 por Dave Grohl, ex-baterista de
Nirvana. La banda ha conseguido varios reconocimientos y ha marcado muchísimos éxitos alrededor del
mundo, tales como "Big Me", "This is a Call", "Everlong", "Monkey Wrench", "Learn to Fly", "All My Life",
"Times Like These", "Best of You", "D.O.A. ", "No Way Back", "The Pretender", que alcanzó el puesto N° 1 en
los Hot Modern5. Rock
Tracks el
sábado
1 de septiembre del 2007 y se mantuvo como número 1 por 18
14
Evaluierung von IR-‐Systemen
semanas consecutivas. Su último single es "Wheels", incluído en su álbum de Grandes Éxitos lanzado el 3 de
is dbpedia-owl:musicalBand of
✦
✦
dbpedia:Generator_(song)
dbpedia:Let_It_Die_(song)
dbpedia:This_Is_a_Call
dbpedia:Walking_After_You
dbpedia:Next_Year
dbpedia:Exhausted_(song)
dbpedia:For_All_the_Cows
dbpedia:My_Hero_(song)
dbpedia:Times_Like_These_(song)
dbpedia:I'll_Stick_Around
dbpedia:Monkey_Wrench_(song)
dbpedia:Everlong
dbpedia:Low_(Foo_Fighters_song)
dbpedia:Breakout_(Foo_Fighters_song)
dbpedia:Have_It_All_(song)
dbpedia:Learn_to_Fly
is dbpedia-owl:producer of
dbpedia:The_Colour_and_the_Shape
dbpedia:There_Is_Nothing_Left_to_Lose
dbpedia:One_by_One
dbpedia:Echoes,_Silence,_Patience_&_Grace
dbpedia:Greatest_Hits_(Foo_Fighters_album)
dbpedia:Foo_Fighters_(album)
dbpedia:In_Your_Honor
dbpedia:Foo_Fighters_Live_at_Wembley_Stadium
dbpedia:I'll_Stick_Around
dbpedia:Five_Songs_and_a_Cover
is dbpedia-owl:wikiPageDisambiguates of dbpedia:FF
is dbpedia-owl:wikiPageRedirects of
dbpedia:Foo_fighters
dbpedia:The_Foo_Fighters
dbpedia:Foo_Fighters_(band)
dbpedia:The_foo_fighters
dbpedia:Foo_Fighters_band_members
dbpedia:THE_FOOS
is dbpprop:associatedActs of
dbpedia:Me_First_and_the_Gimme_Gimmes
dbpedia:Jackson_United
dbpedia:Dain_Bramage
is dbpprop:producer of
is owl:sameAs of
yago-res:Foo Fighters
is foaf:primaryTopic of
http://en.wikipedia.org/wiki/Foo_Fighters
DBpedia
http://dbpedia.org
3.5 Millionen En))es / 670 Millionen Fakten
Browse using: OpenLink Data Explorer | Zitgist Data Viewer | Marbles | DISCO | Tabulator
Raw Data in: CSV | RDF ( N-Triples N3/Turtle JSON
XML ) | OData ( Atom JSON ) About
5. Evaluierung von IR-‐Systemen
14
YAGO
✦
✦
http://www.mpi-inf.mpg.de/yago-naga/yago/
10 Millionen En))es / 80 Millionen Facts
Browse YAGO2
Entity:
case insensitive
← Foo fighters
← Foo Fighters
← Foo Fighters band members
← The foo fighters
← THE FOOS
Foo_Fighters
Show transitive facts
hasWonPrize
means
wasCreatedOnDate
1995-##-## →
hasPreferredName
Foo Fighters →
← Foo Fighters hasPreferredMeaning
hasWikipediaCategory
Grammy Award →
Kerrang! Awards →
1990s music groups →
American alternative rock groups →
American hard rock musical groups →
American post-grunge musical groups →
BRIT Award winners →
Grammy Award winners →
Kerrang! Awards winners →
Musical groups established in 1995 →
Musical groups from Seattle, Washington →
Nirvana (band) →
RCA Records artists →
A320 (song) →
Breakout (Foo Fighters song) →
Echoes, Silence, Patience & Grace →
Everlong →
Everywhere but Home →
Exhausted (song) →
Foo Fighters discography →
15
Foo Fighters Live at Wembley Stadium →
YAGO
✦
✦
American alternative rock groups →
American hard rock musical groups →
American post-grunge musical groups →
Musical groups established in 1995 →
Musical groups from Seattle, Washington →
abstraction →
entity →
group →
musical organization →
organization →
social group →
yagoLegalActor →
yagoLegalActorGeo →
http://www.mpi-inf.mpg.de/yago-naga/yago/
10 Millionen En))es / 80 Millionen Facts
type
hasGivenName
Foo →
hasWikipediaAnchorText
A320 →
ABBA →
acoustic →
Afghan Whigs →
AIDS →
Alanis Morissette →
Alive & Well →
All My Life →
Alternative rock →
Angels & Airwaves →
backing vocals →
Baltimore →
bass guitar →
Bay City Rollers →
Beatles →
Best Hard Rock Performance →
Best of You →
Best Rock Album →
Big Me →
Billboard →
...
hasWebsite
» http://www.foofighters.com/ →
hasGender
male →
hasWikipediaUrl
» http://en.wikipedia.org/wiki/Foo_Fighters →
hasFamilyName
Fighters →
hasNumberOfWikipediaLinks 167 →
15
Freebase
✦
✦
http://www.freebase.com
20 Millionen En))es
Find topics...
Data
Schema
Apps
Docs
Foo Fighters
Sign In or Sign Up
These people have edited this topic:
Scroll to:
Foo Fighters is an American alternative rock band originally formed
Music
in 1994 by Nirvana drummer Dave Grohl as a one-man project
Broadcast Artist
following the dissolution of his previous band. The band got its
Awards
name from the UFOs and various aerial phenomena that were
Film
reported by Allied aircraft pilots in World War II, which were known
TV Actor
collectively as foo fighters. Prior to the release of the Foo Fighters' 1995 debut album Foo
More...
Fighters, which featured Grohl as the ... More
Edit this topic
Last edited Jul 4, 2011 See all topic history »
Related Topics
Read article at Wikipedia
Pearl Jam
Active as Musical Artist (start): 1994
Place Musical Career Began: Seattle, United States of America
Song: Wasting Light
Musical Genres: Rock music, Hard rock, Post-grunge, Alternative rock, Alternative metal, Punk
rock, Post-hardcore, Grunge music
Green Day
Artist: Foo Fighters
Also known as: FooFighters, Foo Fighters
Nirvana
Music
Red Hot Chili Peppers
Albums
16
✦
✦
First appearance:
SNL - 21.7
Most recent
appearance:
Jon Bon Jovi/Foo Fighters
Former cast
member?:
No
Freebase
http://www.freebase.com
20 Millionen En))es
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The album, artist, and track information for Foo Fighters originated from
MusicBrainz.org. The information is Public Domain.
Freebase data is free for use under the CC-BY license.
1
Learn more about Freebase licensing and attribution »
The original description for Foo Fighters was automatically generated from
Wikipedia.org licensed under the GNU Free Documentation License.
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Freebase contains information on: Arts & Entertainment
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©2011
Sports
System
Time & Space
Transportation
16
7.5 SPARQL
✦
✦
SPARQL Protol and Query Language (SPARQL) ist eine vom W3C standardisierte Anfragesprache für das Seman?c Web
Syntax von SPARQL angelehnt an Syntax der Structured Query Language (SQL) zum Anfragen rela)onaler Datenbanken
SELECT name, COUNT(*)
FROM customers
GROUP BY name
✦
✦
SPARQL Anfrage definiert ein Graphmuster (graph pa7ern); Ergebnis sind alle Teilgraphen, welche diesem entsprechen
Linked Open Data schlägt vor, dass Daten miJels SPARQL Schniastelle (SPARQL endpoint) anfragbar sind
17
SPARQL
✦
Beispiel:
PREFIX a: <http://allmusic.org/>
SELECT DISTINCT ?p WHERE {
?b a:hasMember a:Dave_Grohl .
?b a:hasMember ?p .
?p ?r a:Seattle .
}
ORDER BY ?p
18
SPARQL
✦
Beispiel:
PREFIX a: <http://allmusic.org/>
SELECT DISTINCT ?p WHERE {
?b a:hasMember a:Dave_Grohl .
?b a:hasMember ?p .
?p ?r a:Seattle .
}
ORDER BY ?p
e
asM
h
:
a
?b
er
mb
Dave_Grohl
a:h
as
M
em
be
r
?p
?r
Seattle
18
Zusammenfassung
✦
✦
✦
✦
✦
Seman?c Web ist eine Ergänzung des World Wide Webs, mit dem Ziel, Inhalte für Computer verständlich zu machen
Uniform Resource Iden?fiers zur eindeu)gen Iden)fika)on einer abstrakten oder physischen Ressource
Resource Descrip?on Framework als Daten-‐Modell zur Beschreibung von Informa)onen über Ressourcen
Ontologien und Wissensdatenbanken erfassen Wissen über Klassen, deren Instanzen und Rela)onen zwischen diesen SPARQL als Anfragesprache für das Seman)c Web
19
Quellen & Literatur
[1] [2] [3] [4] [5] [6] [7] http://semanticweb.org
http://linkeddata.org
T. Berners-‐Lee, J. Hendler and O. Lassila: The Seman)c Web
Scien)fic American, 2001
http://www.scientificamerican.com/article.cfm?id=the-semantic-web
D. Fensel, J. Hendler, H. Lieberman and W. Wahlster: Spinning the Seman)c Web
MIT Press, 2003
I. Herman: Introduc)on to Seman)c Web Technologies
Seman)c Technology Conference Tutorial, 2010
http://www.w3.org/2010/Talks/0622-SemTech-IH/Tutorial.pdf
P. Mika and T. Tran: Seman)c Search
Seman)c Technology Conference Tutorial, 2011
http://www.slideshare.net/pmika/semtech-2011-semantic-search-tutorial
F. Suchanek, A. Varde, R. Nayak and P. Senellart: The Hidden Web, XML and the Seman)c Web: A Scien)fic Data Management Perspec)ve
EDBT Tutorial, 2011
http://suchanek.name/work/publications/edbt2011tutorial/tutorial.pdf
20

Information Retrieval (SS 2011)

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