Technology amp Status Dr Myungjin Lee The Semantic Web an elemental syntax for content structure within documents a simple language for expressing data models which refer to objects resources ID: 409391
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Slide1
Linked DataTechnology & Status
Dr.
Myungjin
LeeSlide2
The Semantic Web
an elemental
syntax
for
content
structurewithin documents
a simple languagefor expressing data models,which refer to objects ("resources")and their relationships
more vocabularyfor describing properties and classes
a vocabulary for describingproperties and classesof RDF-based resources
a protocol and query languagefor semantic web data sources
to exchange rulesbetween many "rules languages"
a string of characters used to identify a name or a resource
Linked
Data & Semantic Web Technology
http://www.w3.org/2007/Talks/0130-sb-W3CTechSemWeb/#(24)Slide3
What is Linked Data?
Linked
data describes
a method of publishing structured data
so that it can be interlinked and become more
useful.
The Semantic Web isn't just about putting data on the web. It is about
making links
, so that a person or machine can explore the web of data. With linked data, when you have some of it,
you can find other, related, data.- A roadmap to the Semantic Web by Tim Berners-Lee
http://www.w3.org/DesignIssues/LinkedData.htmlSlide4
Four Principles of Linked Data
Use
URIs
to identify things.
Use HTTP URIs so that these things can be referred to and looked up ("dereferenced") by people and user agents.
Provide useful information about the thing when its URI is dereferenced, using standard formats such as RDF/XML.Include links to other, related URIs in the exposed data to improve discovery of other related information on the Web.
http://www.w3.org/DesignIssues/LinkedData.htmlSlide5
5 Star Linked Data
★
Available on the web (whatever format) but with an open
licence
, to be Open Data
★★Available as machine-readable structured data (e.g. excel instead of image scan of a table)
★★★as (2) plus non-proprietary format (e.g. CSV instead of excel) ★★★★All the above plus, Use
open standards from W3C (RDF and SPARQL) to identify things, so that people can point at your stuff
★★★★★All the above, plus: Link your data to other people’s data to provide context
http://www.w3.org/DesignIssues/LinkedData.htmlSlide6
The Basic Requirements
for
Linked Data
an elemental
syntax
for content structurewithin documents
a simple languagefor expressing data models,which refer to objects ("resources")and their relationships
a vocabulary for describingproperties and
classesof RDF-based resourcesa protocol and query languagefor semantic web data sources
a string of characters used to identify a name or a resource
Linked
Data & Semantic Web TechnologySlide7
http://
www.google.co.kr/search?q=namdeamunSlide8
URI, Thing, and Representation
Thing
URI
Representation
http://data.kdata.kr/resource/Namdaemun
<html
xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>
Namdaemun | kdata.kr</title> <link rel="alternate" type="application/rdf+xml"
href="http://data.kdata.kr/data/Namdaemun" title="RDF" /></head> <body onLoad="init
();"> <div id="header"> <div> <h1 id="title">Namdaemun</h1> <div id="
homelink"> at <a href="http://kdata.kr">kdata.kr</a>
identifies
and
names
represents
looks up
URI
http://
dbpedia.org/resource/Namdaemun
URI
http://data.kdata.kr/resource/Sungnyemun
links
refers
Person
Machine
http://www.slideshare.net/lysander07/open-hpi-semweb02part1Slide9
http://www.w3.org/TR/cooluris/Slide10
URIs for Real-World Objects
Be on the Web
Given only a URI, machines and people should be able
to retrieve a description about the resource
identified by the URI from the Web.Be unambiguousThere should be no confusion between identifiers for Web documents and identifiers for other resources.
http://www.w3.org/TR/cooluris/Slide11
URIs for Real-World Objects
<URI-of-
alice
>
a foaf:Person;
foaf:name "Alice"; foaf:mbox <mailto:alice@example.com>;
foaf:homepage <http://www.example.com/people/alice> .ID
RDF
HTMLResource identifier (URI)RDF document URI
HTML document URI
for web browsers
for semantic web applications
http://www.w3.org/TR/cooluris/Slide12
Distinguishing between Representations and Descriptions
Generic
Document
RDF
HTML
http://data.kdata.kr/page/Namdaemun
http://data.kdata.kr/page/Namdaemun.rdfhttp://data.kdata.kr/page/Namdaemun.html
text/html
application/rdf+xml
Thing
http://data.kdata.kr/resource/Namdaemun
303 redirect
contentnegotiationSlide13
Cool URIs
Simplicity
short and mnemonic
Stabilityremain as long as possible
Manageabilityissue your URIs in a way that you can managehttp://www.w3.org/TR/cooluris/Slide14
Designing URI Sets for the UK Public Sector
URIs:
name
the set and describe its characteristics
identify for the real-world ‘Things’ in a single conceptprovide a means of looking up data on the webprovide mechanisms to: lookup an Identifier URI and be redirected to its Document URI
discover and get each of the Representation URIsURI TypeURI structure
ExamplesIdentifierhttp://{domain}/id/{concept}/{reference}http://education.data.gov.uk/id/school/78
https://www.gov.uk/government/publications/designing-uri-sets-for-the-uk-public-sectorhttp://data.gov.uk/resources/urisSlide15
URI Design
Principles:
Creating
Unique URIs for Government Linked Data
URI Template
:'http://' BASE '/' 'id' '/' ORG '/' CATEGORY ( '/' TOKEN )+States and TerritoriesOwnerfederalSuggestedhttp://BASE/id/us/state/NAMEExamplehttp://logd.tw.rpi.edu/id/us/state/Vermont
http://logd.tw.rpi.edu/instance-hub-uri-designSlide16
XML (Extensible Markup Language)
a textual data format for
the
representation of arbitrary data structures
over the Internetboth human-readable and machine-readable
<title> W3C Demonstrates …
</title><date> 12 February 2013</date>
<body>
W3C invites media, analysts, and other attendees
of Mobile World Congress …</body
>
Content
title
date
body
bold1
bold2
Structure
title
date
body
bold1
bold2
Presentation
XML
DTD
XML Schema
XSLT
XSL-
fo
XPath
Concept
Related
Recommendations
http://en.wikipedia.org/wiki/XmlSlide17
Data Representation of XML
Various ways to represent data using XML
Myungjin
Lee is Hye-jin’s husband.
We need a method to represent data on abstract level.
<conjugalrelation> <husband>Myungjin
Lee</husband> <wife>Hye-jin Han</wife></conjugalrelation>
<conjugalrelation husband=“Myungjin Lee”>
<wife>Hye-jin Han</wife></conjugalrelation>
<conjugalrelation husband=“
Myungjin Lee” wife=“Hye-jin Han” />Slide18
RDF (Resource Description Framework)
a general
method for conceptual description or modeling of information
that is implemented in web resources, using a variety of syntax formats
Myungjin Lee is Hye-jin’s husband.
hasWife
http://en.wikipedia.org/wiki/Resource_Description_FrameworkSlide19
Data Representation of RDF
hasWife
http://semantics.kr/myungjinlee
http://semantics.kr/hye-jinhan
http://
semantics.kr/rel/hasWife
Subject
URI reference
Predicate
URI reference
ObjectURI reference or Literal
TripleSlide20
RDF Example
http://www.cars.com/car#A6
http://www.cars.com/car#Car
http://www.cars.com/car#Gasoline
http://www.cars.com/car#GDI
http://www.cars.com/car#Auto_8-Speed
http://www.cars.com/car#Sedan
4
http://www.cars.com/car#AWD
115”
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.cars.com/car#transmission
http://www.cars.com/car#wheelbase
http://www.cars.com/car#engine
http://www.cars.com/car#fuel
http://www.cars.com/car#drivetrain
http://www.cars.com/car#doors
http://www.cars.com/car#body_styleSlide21
RDF Serialization
N-Triples
RDF Test
Cases, W3C Recommendation, 10 February 2004
a line-based, plain text serialization format for storing and transmitting RDF dataNotation 3 (N3)a shorthand non-XML serialization of RDF models, designed with human-readability in
mindmuch more compact and readable than XML RDF notationTurtle (Terse RDF Triple Language)W3C Candidate Recommendation, 19 February 2013a format for expressing data in the Resource Description Framework (RDF) data modela subset of Notation3 (N3) language, and a superset of the minimal N-Triples formatRDF/XMLW3C Recommendation, 10 February 2004
an XML syntax for writing down and exchanging RDF graphshttp://en.wikipedia.org/wiki/N-Tripleshttp://en.wikipedia.org/wiki/Notation3http://en.wikipedia.org/wiki/Turtle_(syntax)Slide22
<http://en.wikipedia.org/wiki/Tony_Benn> <http://purl.org/dc/elements/1.1/title> "Tony Benn" .
<http://en.wikipedia.org/wiki/Tony_Benn> <http://purl.org/dc/elements/1.1/publisher> "Wikipedia" .
<
rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
<rdf:Description rdf:about="http://en.wikipedia.org/wiki/Tony_Benn"> <
dc:title>Tony Benn</dc:title>
<dc:publisher>Wikipedia</dc:publisher> </rdf:Description
></rdf:RDF>
@prefix dc: <http://purl.org/dc/elements/1.1/>.<http://en.wikipedia.org/wiki/Tony_Benn> dc:title "Tony Benn";
dc:publisher "Wikipedia".
@prefix
rdf
: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix dc: <http://purl.org/dc/elements/1.1/> .
@prefix ex: <http://example.org/stuff/1.0/> .
<http://
www.w3.org/TR/rdf-syntax-grammar> dc:title
"RDF/XML Syntax Specification (Revised)" ;
ex:editor [ ex:fullname
"Dave Beckett"; ex:homePage
<http://purl.org/net/dajobe/> ]
.N-Triple
RDF/XML
N3
TurtleSlide23
http://www.w3.org/TR/rdf11-concepts/Slide24
RDF 1.0 vs RDF 1.1
RDF 1.0
RDF 1.1
Resource Identification
URI
IRI (Internationalized Resource Identifier)
Multiple RDF GraphsXOHTML content for literal valueX
rdf:HTMLSlide25
Recommendations of RDF
http://www.w3.org/standards/techs/rdf#w3c_allSlide26
RDF Schema
W3C
Recommendation,
10 February 2004to define classes and properties that may be used to describe classes, properties and other
resourcesRDF Schema allowsDefinition of ClassesDefinition of
Properties and RestrictionsDefinition of Hierarchieshttp://www.slideshare.net/lysander07/openhpi-22Slide27
RDF Schema Example
car:Car
car:Vehicle
rdfs:subClassOf
rdf:Property
car:body_style
rdfs:domain
rdfs:range
rdfs:Class
rdf:type
rdf:type
car:Style
rdf:type
car:A6
rdf:type
car:Sedan
rdf:type
car:body_style
ABox
- assertion component
TBox
- terminological componentSlide28
RDF Semantics
to provide
a formal meaning based on a model-theoretic semantics
in its abstract syntax
<
x, y> is in IEXT(I(rdfs:subClassOf))if and only if x and
y are in ICand ICEXT(x) is a subset of ICEXT(y)car:Car
car:Vehiclerdfs:subClassOf
car:A6
rdf:type
rdf:typeSlide29
SPARQL
Why do we need a query language for RDF?
Why de we need a query language for RDB?
to get to the knowledge from RDF
SPARQL Protocol and RDF Query Languageto retrieve and manipulate data stored in Resource Description Framework formatto use SPARQL
via HTTPhttp://www.slideshare.net/lysander07/openhpi-semweb03part1Slide30
SPARQL Example
PREFIX
foaf
: <http://xmlns.com/foaf/0.1/> SELECT ?name ?
emailWHERE {
?person a foaf:Person. ?person
foaf:name ?name. ?person foaf:mbox ?email.}
RDF Knowledge Base
?name?email
Myungjin Leemjlee@li-st.com
Gildong Honggildong@daum.net
Grace Byungrace@naver.comSlide31
SPARQL Query Forms
SELECT query
Used
to extract raw values from a SPARQL endpoint, the results are returned in a table format. CONSTRUCT query
Used to extract information from the SPARQL endpoint and transform the results into valid RDF.ASK queryUsed to provide a simple True/False result for a query on a SPARQL endpoint. DESCRIBE queryUsed
to extract an RDF graph from the SPARQL endpoint, the contents of which is left to the endpoint to decide based on what the maintainer deems as useful information.http://en.wikipedia.org/wiki/SPARQLSlide32
OWL (Web Ontology Language)
knowledge representation languages for authoring
ontologies
If you need more
expressiveness OWLsuch as,
ManWoman
∩= Ø
PersonPerson
descendant
Person
descendant
descendant
Husband
Wife
1:1
_01
Action
hasGenre
ActionMovie
subClassOf
Genre
typeSlide33
Linked Data Service
What more do
we
need?
Triple Store
RDBMS
HTML
HTML
HTML
SPARQL
R2RML
Linked Data Platform
RDFa
GRDDL
RDF
Knowledge
+Slide34
R2RML
RDB to RDF Mapping
Language
W3C Recommendation 27 September 2012a language for
expressing customized mappings from relational databases to RDF datasets<
http://data.example.com/employee/7369> rdf:type ex:Employee.<http://data.example.com/employee/7369> ex:name "SMITH".
@prefix rr: <http://www.w3.org/ns/r2rml#>.@prefix ex: <http://example.com/ns#>.
<#TriplesMap1> rr:logicalTable [
rr:tableName "EMP" ]; rr:subjectMap [ rr:template "http://data.example.com/employee/{EMPNO}";
rr:class ex:Employee; ];
rr:predicateObjectMap [ rr:predicate ex:name
; rr:objectMap
[ rr:column
"ENAME" ]; ].
R2RML
Result
RDB
http://www.w3.org/TR/r2rml/Slide35
Linked Data Platform
A set of best practices and simple approach for
a read-write Linked Data architecture, based on HTTP
access to web resources that describe their state using RDFW3C Working Draft 25 October 2012
http://www.w3.org/TR/ldp/Slide36
RDFa (the Resource Description Framework in attributes)
W3C
Recommendation,
07 June 2012to
express machine-readable data in Web documents like HTML, SVG, and XML
Example<p vocab="http://schema.org/" resource="#manu" typeof="Person">
My name is <span property="name">Manu Sporny</span> and you can give me a ring via <span property="telephone">
1-800-555-0199</span>. <img
property="image" src="http://manu.sporny.org/images/manu.png" /></p>
http://www.w3.org/TR/xhtml-rdfa-primer/Slide37
GRDDL (Gleaning Resource Descriptions from Dialects of Languages)
a
mechanism
and markup format
for Gleaning Resource Descriptions from Dialects of Languages to obtain RDF triples out of XML documents, including XHTML
<html xmlns:grddl='http://www.w3.org/2003/g/data-view#' grddl:transformation="glean_title.xsl getAuthor.xsl
"><head><title>Are You Experienced?</title></head>...
<xsl:stylesheet version="1.0"> <
xsl:template match="/"> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <
rdf:Description rdf:about="{$subject}"> <dc:title
> <xsl:value-of select="/html:html
/html:head/
html:title"/>
</dc:title
> </
rdf:Description> </
rdf:RDF
> </xsl:template
></
xsl:stylesheet>
<
rdf:RDF>
<
rdf:Description rdf:about
=""> <
dc:title>Are You Experienced?</dc:title
> </rdf:Description></rdf:RDF>
HTML
glean_title.xsl
RDF
http://www.w3.org/TR/grddl/Slide38
Jena Platform
Linked Data Service
Triple Store
RDBMS
HTML
HTML
HTML
SPARQL
TDB & SDB
Jena API
Fuseki
ARQ & LARQ
http://jena.apache.org/Slide39
Openlink Virtuoso
a middleware and database engine hybrid that combines the functionality of a traditional RDBMS, ORDBMS,
RDF
, XML, etc.Relational
Data ManagementRDF Data ManagementXML Data ManagementFree Text Content Management & Full Text Indexing
Document Web ServerLinked Data ServerWeb Application ServerWeb Services Deployment (SOAP or REST)http://virtuoso.openlinksw.com/Slide40
Openlink Virtuoso Coverage
Linked Data Service
Triple Store
RDBMS
HTML
HTML
HTML
SPARQL
Sponger
SPARQL Server
Storage and InferenceSlide41
The Linking Open Data cloud diagram
Linked
Data & Semantic Web Technology
http://lod-cloud.net/Slide42
Media
User Generated Content
Publications
Government
Geographic
Cross-Domain
Life Sciences
Linked
Data & Semantic Web Technology
Domain
Number of datasets
Triples
(Out-)Links
Media
25
18,4185,2061
5044,0705
Geographic
31
61,4553,2484
3581,2328
Government
49
133,1500,9400
1934,3519
Publications
8729,5072,0693
1,3992,5218
Cross-domain
41
41,8463,5715
6318,3065
Life Sciences
41
30,3633,6004
1,9184,4090
User-generated Content
20
1,3412,7413
344,9143
Total
295
316,3421,3770
5,0399,8829
http://www.slideshare.net/lysander07/13-semantic-web-technologies-linked-data-semantic-searchSlide43
Linked
Data & Semantic Web Technology
KDATA (Linked Data for Korea)
Domain
Triples
국가코드
3,899
엔터테인먼트
44,278
행정구역 2,969
초중고등학교
126,469
교육청
1,130 대학교
2,833
사회적 기업
5,539
서울시 개방 화장실
47,340
야구선수 및 팀
228,872
지하철역
4,450 역사 5,392 행정데이터표준용어 109,101 한옥마을
1,155
공공
WiFi
설치정보
1,671
KDATA
분류용어
808
전통시장
4,535
국립공원
10,605
문화재
80,156
공공체육시설
49,799
생물분류
3,256
문화시설
9,418
공원정보 및 프로그램
2,429
가격안정모범업소
16,212
가격안정모범업소 상품목록
14,300
공공시설물 인증제품
6,931
제설함 위치정보
39,218
야생동식물정보
115,099
야생동식물 출현정보
139,608
합계
1,077,472
http://kdata.kr/index.jspSlide44
<
rdf:RDF
>
<
rdf:Description
rdf:about="http://data.kdata.kr/data/Namdaemun?output=rdfxml"> <
rdfs:label>RDF description of Namdaemun</rdfs:label>
<foaf:primaryTopic> <kdc:StateDesignatedHeritage
rdf:about="http://data.kdata.kr/resource/Namdaemun">
<rdfs:label>남대문</
rdfs:label>
<
rdfs:label>
숭례문</
rdfs:label>
<
foaf:depiction rdf:resource
="20060227132556895000.jpg"/>
<
owl:sameAs
rdf:resource="http://dbpedia.org/resource/Namdaemun
"/>
...</rdf:RDF
>
http://data.kdata.kr/resource/Namdaemun
HTMLRDF
select ?s
where {
?s
rdf:type
<http://data.kdata.kr/class/NationalTreasure>
.
?s
rdfs:label
"
남대문
"
.
}
SPARQLSlide45
Dr.
Myungjin
Lee
e-Mail : mjlee@li-st.com
Twitter : http://twitter.com/MyungjinLee
Facebook
: http://www.facebook.com/mjinleeSlideShare : http://www.slideshare.net/onlyjiny/
Thanks foryour attention.