Overview of Semantic Web and RDF Concepts
M2
MLDM/DSC
– Semantic Web
Maxime Lefrançois
adapted from slides from Lynda Témal,https://fr.linkedin.com/in/lynda-temal-32a206a/fr
w
hich are adapted from slides from Fabien Gandon, Inria.
2. International Resource Identifier
Resource Description Framework
and the Turtle syntax
Semantic Web Formalisms
Querying
Reasoning
Trust
2
Representation
Semantic Web Formalisms
Querying
Reasoning
Trust
3
RDF
R
esource
:
company, building, sensor,
temperature, unit, …
D
escription
: attributes, quality, and relations
between ressources
F
ramework
: model, languages and
syntaxes for these descriptions
4
R
D
F
: a triple model
(
subject
,
predicate
,
object
)
Structure of a simple sentence
Lynda
works_at
Engie
(
subject
,
verb
, object)
5
R
D
F
: A set of triples
= a RDF graph
6
This cannot be interpreted by a machine
Timothy John Berners-Lee,
B
orn June 8th 1955 in Londres.
Is the principal inventor of the World Wide Web.
President of the World Wide Web Consortium (W3C),
which he founded.
Author of the book a Framework for Web Science
.
7
Identification : Ressources & Relations
8
Timothy John Berners-Lee,
Born
June 8th 1955
in
Londres
.
Is the principal
inventor
of
the World Wide Web
.
President of
the World Wide Web Consortium (W3C)
,
which he
founded
.
Author of
the
book a Framework for Web Science
.
Simple sentence
T
imBL
has date of birth
1955-06-08.
T
imBL
has place of birth
London.
T
imBL
is inventor of
WWW.
T
imBL
is director of
W3C.
T
imBL
is founder of
W3C.
T
imBL
is author of
Framework for Web Sience
9
R
D
F
Triples: interpretable by the
machine
(
T
imBL
,
dateOfBirth
,
1955-06-08
)
(
T
imBL
,
placeOfBirth
,
London
)
(
T
imBL
,
isInventorOf
,
WWW
)
(
T
imBL
,
isDirectorOf
,
W3C
)
(
T
imBL
,
isFounderOf
,
W3C
)
(
T
imBL
,
isAuthorOf
,
Web_Science
)
(
Sujet
,
predicat
,
Objet
)
10
R
D
F
triples can be
r
epresented by a oriented graph
(
node
,
arc
,
node
)
11
T
i
m
B
L
W
3
C
1
9
5
5
-
0
6
-
0
8
d
a
t
e
O
f
B
i
r
t
h
i
s
F
o
u
n
d
e
r
O
f
12
Rules to write
R
D
F
triples
➢
The
subject
is always a resource (never a literal)
➢
The
predicates
are binary relations identified by URIs
➢
The
object
is a resource or a literal
13
How to identify something uniquely?
14
URL: Universal Resource Locator
URN: Universal Resource Name
urn:isbn:0-395-36341-1 (réf. RFC 3187)
urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 (réf. RFC 4122)
urn:ietf:rfc:2141 (réf. RFC 2648)
See list
https://www.iana.org/assignments/urn-namespaces/urn-namespaces.xhtml
15
URI = URN and URI
16
T
i
m
B
L
W
3
C
1
9
5
5
-
0
6
-
0
8
d
a
t
e
O
f
B
i
r
t
h
i
s
F
o
u
n
d
e
r
O
f
17
http://dbpedia.org/resource/Tim_Berners-Lee
http://www.w3.org
http://dbpedia.org/ontology/birthDate
http://dbpedia.org/property/founder
1955-06-08
18
http://dbpedia.org/resource/Tim_Berners-Lee
http://www.w3.org
http://dbpedia.org/ontology/birthDate
http://dbpedia.org/property/founder
"1955-06-08"^^<
http://www.w3.org/2001/XMLSchema#
>
19
(one of ~) RDF syntaxes - N-Triple
<
http://dbpedia.org/resource/Tim_Berners-Lee
>
<
http://purl.org/dc/terms/creator
>
<
http://www.w3.org
>.
<
http://dbpedia.org/resource/Tim_Berners-Lee
>
<
http://dbpedia.org/property/dateOfBirth
>
“1955-06-08”^^<http://www.w3.org/2001/XMLSchema#date>.
<
http://dbpedia.org/resource/Tim_Berners-Lee
>
<
http://dbpedia.org/property/placeOfBirth
>
<http://dbpedia.org/resource/London>.
<
http://dbpedia.org/resource/London
>
<
http://dbpedia.org/property/isPartOf
>
<http://dbpedia.org/resource/England>.
20
(one of ~) RDF syntaxes -
Turtle
Syntactic sugar ++
21
Turtle prefixes and bases
<http://example.org/instances/appartement418>
<
http://www.w3.org/1999/02/22-rdf-syntax-ns#
type>
<http://example.org/vocabulary/T2>
.
=
@Prefix rdf: <
http://www.w3.org/1999/02/22-rdf-syntax-ns#
>.
@Prefix : <http://example.org/vocabulary/> .
@Base <http://example.org/instances/> .
<
appartement418
> rdf:
type
:
T2
.
22
@Prefix rdf: <
http://www.w3.org/1999/02/22-rdf-syntax-ns#
>.
@Prefix dbp: <
http://dbpedia.org/property/>.
@Prefix
dbr: <
http://dbpedia.org/resource/>.
@Prefix dc: <
http://purl.org/dc/terms/>.
@Prefix xsd: <
http://www.w3.org/2001/XMLSchema#
>.
dbr:
Tim_Berners-Lee
rdf:
type
dbo:
Scientist
.
dbr:
Tim_Berners-Lee
dc:
creator
<
http://www.w3.org>
.
dbr:
Tim_Berners-Lee
dbp:
dateOfBirth
“1955-06-08”^^
xsd:
date
.
dbr:
Tim_Berners-Lee
dbp:
placeOfBirth
dbr:
London
.
dbr:
Tim_Berners-Lee
dbp:
placeOfBirth
dbr:
England
.
dbr:
London
dbp:
isPartOf
dbr:
England
.
23
Turtle prefixes and bases
Separators « . » - « ; »
@Prefix rdf: <
http://www.w3.org/1999/02/22-rdf-syntax-ns#
>.
@Prefix dbp: <
http://dbpedia.org/property/>.
@Prefix
dbr: <
http://dbpedia.org/resource/>.
@Prefix dc: <
http://purl.org/dc/terms/>.
@Prefix xsd: <
http://www.w3.org/2001/XMLSchema#
>.
dbr:
Tim_Berners-Lee
rdf:
type
dbo:
Scientist
;
dc:
creator
<
http://www.w3.org>
;
dbp:
dateOfBirth
“1955-06-08”^^
xsd:
date
;
dbp:
placeOfBirth
dbr:
London
;
dbp:
placeOfBirth
dbr:
England
.
dbr:
London
dbp:
isPartOf
dbr:
England
.
24
Separators « . » - « ; » - « , »
@Prefix rdf: <
http://www.w3.org/1999/02/22-rdf-syntax-ns#
>.
@Prefix dbp: <
http://dbpedia.org/property/>.
@Prefix
dbr: <
http://dbpedia.org/resource/>.
@Prefix dc: <
http://purl.org/dc/terms/>.
@Prefix xsd: <
http://www.w3.org/2001/XMLSchema#
>.
dbr:
Tim_Berners-Lee
rdf:
type
dbo:
Scientist
;
dc:
creator
<
http://www.w3.org>
;
dbp:
dateOfBirth
“1955-06-08”^^
xsd:
date
;
dbp:
placeOfBirth
dbr:
London
,
dbr:
England
.
dbr:
London
dbp:
isPartOf
dbr:
England
.
25
26
Check out these tools:
http://prefix.cc/
https://perfectkb.github.io/yate/
How to say: « There exists something that… » with
R
D
F
?
Anonymous nodes (blank node)
27
How to say: « There exists something that… » with
R
D
F
?
dbr:
Tim_Berners-Lee
dbo:
marriedTo
_:
bnode1
.
_:
bnode1
foaf:firstName "Nancy" ;
foaf:lastName "Carlson" .
Anonymous nodes (blank node)
28
How to say: « There exists something that… » with
R
D
F
?
dbr:
Tim_Berners-Lee
dbo:marriedTo [
foaf:firstName "Nancy" ;
foaf:lastName "Carlson" ] .
@Prefix foaf: <http://xmlns.com/foaf/0.1/> .
# Someone knows someone else, who has the name "Bob".
[ ] foaf:knows [ foaf:name "Bob" ] .
Anonymous nodes (blank node)
29
How to represent a closed list in
R
D
F
?
W
e
b
_
S
c
i
e
n
c
e
h
a
s
f
o
r
c
h
a
p
t
e
r
:
1
.
c
h
a
p
1
2
.
c
h
a
p
2
3
.
c
h
a
p
3
30
(
Web_Science
,
hasChapter
,
_:a
)
(
_:a
,
rdf:first
,
chap1
)
(
_:a
,
rdf:rest
,
_:b
)
(
_:b
,
rdf:first
,
chap2
)
(
_:b
,
rdf:rest
,
_:c
)
(
_:c
,
rdf:first
,
chap3
)
(
_:c
,
rdf:rest
,
rdf:nil
)
rdf:first
and
rdf:rest
→ to chain
rdf:nil
→ to end the list
How to represent a closed list in
R
D
F
?
31
<Web_Science>
ex:
hasChapter
_:a
_:a
rdf:first
ex:
chap1 ;
rdf:rest
_:b .
_:b
rdf:first
ex:
chap2 ;
rdf:rest
_:c .
_:c
rdf:first
ex:
chap3 ;
rdf:rest
rdf:nil.
How to represent a closed list in
Turtle
?
32
<Web_Science>
ex:
hasChapter
[
rdf:first
ex:
chap1 ;
rdf:rest
[
rdf:first
ex:
chap2 ;
rdf:rest
[
rdf:first
ex:
chap3 ;
rdf:rest
rdf:nil ] ] ] .
How to represent a closed list in
Turtle
?
33
OR (because that was still a bit verbose)
<Web_Science>
ex:
hasChapter
(
ex:
chap1
ex:
chap2
ex:
chap3
)
.
How to represent a closed list in
Turtle
?
34
@Prefix : <http://example.org/stuff/1.0/> .
(1 [:p :q] ( 2 ) ) :p2 :q2 .
Can complexify at will
35
RDF Datatype
A datatype
D
is defined by:
A set
L(D)
of Unicode strings called the
Lexical Space
A set
V(D)
called the
Value Space
;
A mapping
L2V(D) : L(V)
V(D),
called the Lexical-to-value mapping,
maps all Strings in the lexical space to a value in the value space.
A Literal
L
with datatype
D
:
In Turtle: "xxx"^^aaa, with:
xxx is the
Lexical Form
aaa is the IRI that
identifies
datatype D
a
"2015-11-23T14:00:00+02:00"
"2015-11-23T12:00:00Z"
L2V(xsd:dateTime
I
)
L2V(
xsd:dateTime
I
)("2015-11-23T12:00:00Z" )= L2V(
xsd:dateTime
I
)("2015-11-23T14:00:00+02:00")L(xsd:dateTime
I
)
"blabla"
∉
L(xsd:dateTime
I
)
Time
e.g., Time dimension,
Datatype for positions -> xsd:dateTime
Datatype for distance -> xsd:duration
"P1Y"
– one year
"PT0S"
– zero second
"P1Y2M"
–
1 year, 2 months
L2V(xsd:duration
I
)
What can I find
when I look-up a IRI* ?
* If I can look it up, it’s obviously a URL (Locator):
not a URN,
not a literal (but maybe its datatype)
http://dbpedia.org/resource/Tim_Berners-Lee
38
je suis Lynda TEMAL
Je suis chez sfeir depuis un an.
J’ai un doctorat de l’université de Rennes I.
Le sujet de la thèse modélisation d’ontologies pour le partage de données dans le domaine de la neuroimagerie.
Aujourd’hui je vais vous présenter une introduction au web semantique. appelé aussi web de données.
This content delves into concepts related to Semantic Web, RDF (Resource Description Framework), and formalisms of Trust Reasoning Representation. It covers topics such as RDF resource description, triple models, machine interpretation challenges, and the role of key figures like Timothy John Berners-Lee in the development of the World Wide Web.
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M2 MLDM/DSC Semantic Web http://ci.mines-stetienne.fr/teaching/websem/2018 2. International Resource Identifier Resource Description Framework and the Turtle syntax Maxime Lefran ois maxime.lefrancois@emse.fr adapted from slides from Lynda T mal, https://fr.linkedin.com/in/lynda-temal-32a206a/fr which are adapted from slides from Fabien Gandon, Inria.
Semantic Web Formalisms Trust Reasoning Representation 2
Semantic Web Formalisms Trust Reasoning 3
RDF Resource: company, building, sensor, temperature, unit, Description: attributes, quality, and relations between ressources Framework: model, languages and syntaxes for these descriptions 4
RDF : a triple model ( subject , predicate, object ) Structure of a simple sentence Lynda works_at Engie ( subject , verb, object) 5
RDF : A set of triples = a RDF graph 6
This cannot be interpreted by a machine Timothy John Berners-Lee, Born June 8th 1955 in Londres. Is the principal inventor of the World Wide Web. President of the World Wide Web Consortium (W3C), which he founded. Author of the book a Framework for Web Science. 7
Identification : Ressources & Relations Timothy John Berners-Lee, Born June 8th 1955 in Londres. Is the principal inventor of the World Wide Web. President of the World Wide Web Consortium (W3C), which he founded. Author of the book a Framework for Web Science. 8
Simple sentence TimBL has date of birth 1955-06-08. TimBL has place of birth London. TimBL is inventor of WWW. TimBL is director of W3C. TimBL is founder of W3C. TimBL is author of Framework for Web Sience 9
RDF Triples: interpretable by the machine (TimBL, dateOfBirth, 1955-06-08) (TimBL, placeOfBirth, London) (TimBL, isInventorOf, WWW) (TimBL, isDirectorOf, W3C) (TimBL, isFounderOf, W3C) (TimBL, isAuthorOf, Web_Science) (Sujet, predicat, Objet) 10
RDF triples can be represented by a oriented graph (node, arc, node) 11
1955-06-08 dateOfBirth TimBL isFounderOf W3C 12
Rules to write RDF triples The subject is always a resource (never a literal) The predicates are binary relations identified by URIs The object is a resource or a literal 13
URL: Universal Resource Locator URN: Universal Resource Name urn:isbn:0-395-36341-1 (r f. RFC 3187) urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 (r f. RFC 4122) urn:ietf:rfc:2141 (r f. RFC 2648) See list https://www.iana.org/assignments/urn-namespaces/urn-namespaces.xhtml 15
1955-06-08 dateOfBirth TimBL isFounderOf W3C 17
1955-06-08 http://dbpedia.org/ontology/birthDate http://dbpedia.org/resource/Tim_Berners-Lee http://dbpedia.org/property/founder http://www.w3.org 18
"1955-06-08"^^<http://www.w3.org/2001/XMLSchema#> http://dbpedia.org/ontology/birthDate http://dbpedia.org/resource/Tim_Berners-Lee http://dbpedia.org/property/founder http://www.w3.org 19
(one of ~) RDF syntaxes - N-Triple <http://dbpedia.org/resource/Tim_Berners-Lee> <http://purl.org/dc/terms/creator> <http://www.w3.org>. <http://dbpedia.org/resource/Tim_Berners-Lee> <http://dbpedia.org/property/dateOfBirth> 1955-06-08 ^^<http://www.w3.org/2001/XMLSchema#date>. <http://dbpedia.org/resource/Tim_Berners-Lee> <http://dbpedia.org/property/placeOfBirth> <http://dbpedia.org/resource/London>. <http://dbpedia.org/resource/London> <http://dbpedia.org/property/isPartOf> <http://dbpedia.org/resource/England>. 20
(one of ~) RDF syntaxes -Turtle Syntactic sugar ++ 21
Turtle prefixes and bases <http://example.org/instances/appartement418> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.org/vocabulary/T2> . = @Prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. @Prefix : <http://example.org/vocabulary/> . @Base <http://example.org/instances/> . <appartement418> rdf:type :T2 . 22
Turtle prefixes and bases @Prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. @Prefix dbp: <http://dbpedia.org/property/>. @Prefix dbr: <http://dbpedia.org/resource/>. @Prefix dc: <http://purl.org/dc/terms/>. @Prefix xsd: <http://www.w3.org/2001/XMLSchema#>. dbr:Tim_Berners-Lee rdf:type dbo:Scientist . dbr:Tim_Berners-Lee dc:creator <http://www.w3.org> . dbr:Tim_Berners-Lee dbp:dateOfBirth 1955-06-08 ^^xsd:date . dbr:Tim_Berners-Lee dbp:placeOfBirth dbr:London . dbr:Tim_Berners-Lee dbp:placeOfBirth dbr:England . dbr:London dbp:isPartOf dbr:England . 23
Separators . - ; @Prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. @Prefix dbp: <http://dbpedia.org/property/>. @Prefix dbr: <http://dbpedia.org/resource/>. @Prefix dc: <http://purl.org/dc/terms/>. @Prefix xsd: <http://www.w3.org/2001/XMLSchema#>. dbr:Tim_Berners-Lee rdf:type dbo:Scientist ; dc:creator <http://www.w3.org> ; dbp:dateOfBirth 1955-06-08 ^^xsd:date ; dbp:placeOfBirth dbr:London ; dbp:placeOfBirth dbr:England . dbr:London dbp:isPartOf dbr:England . 24
Separators . - ; - , @Prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. @Prefix dbp: <http://dbpedia.org/property/>. @Prefix dbr: <http://dbpedia.org/resource/>. @Prefix dc: <http://purl.org/dc/terms/>. @Prefix xsd: <http://www.w3.org/2001/XMLSchema#>. dbr:Tim_Berners-Lee rdf:type dbo:Scientist ; dc:creator <http://www.w3.org> ; dbp:dateOfBirth 1955-06-08 ^^xsd:date ; dbp:placeOfBirth dbr:London , dbr:England . dbr:London dbp:isPartOf dbr:England . 25
Check out these tools: http://prefix.cc/ https://perfectkb.github.io/yate/ 26
How to say: There exists something that with RDF ? Anonymous nodes (blank node) 27
How to say: There exists something that with RDF ? Anonymous nodes (blank node) dbr:Tim_Berners-Lee dbo:marriedTo _:bnode1 . _:bnode1 foaf:firstName "Nancy" ; foaf:lastName "Carlson" . 28
How to say: There exists something that with RDF ? Anonymous nodes (blank node) dbr:Tim_Berners-Lee dbo:marriedTo [ foaf:firstName "Nancy" ; foaf:lastName "Carlson" ] . @Prefix foaf: <http://xmlns.com/foaf/0.1/> . # Someone knows someone else, who has the name "Bob". [ ] foaf:knows [ foaf:name "Bob" ] . 29
How to represent a closed list in RDF ? Web_Science has for chapter: 1. chap1 2. chap2 3. chap3 30
How to represent a closed list in RDF ? rdf:first and rdf:rest to chain rdf:nil to end the list (Web_Science, hasChapter, _:a) (_:a, rdf:first, chap1) (_:a, rdf:rest, _:b) (_:b, rdf:first, chap2) (_:b, rdf:rest, _:c) (_:c, rdf:first, chap3) (_:c, rdf:rest, rdf:nil) 31
How to represent a closed list in Turtle ? <Web_Science> ex:hasChapter _:a _:a rdf:first ex:chap1 ; rdf:rest _:b . _:b rdf:first ex:chap2 ; rdf:rest _:c . _:c rdf:first ex:chap3 ; rdf:rest rdf:nil. 32
How to represent a closed list in Turtle ? <Web_Science> ex:hasChapter [ rdf:first ex:chap1 ; rdf:rest [ rdf:first ex:chap2 ; rdf:rest [ rdf:first ex:chap3 ; rdf:rest rdf:nil ] ] ] . 33
How to represent a closed list in Turtle ? OR (because that was still a bit verbose) <Web_Science> ex:hasChapter ( ex:chap1 ex:chap2 ex:chap3 ) . 34
Can complexify at will @Prefix : <http://example.org/stuff/1.0/> . (1 [:p :q] ( 2 ) ) :p2 :q2 . 35
RDF Datatype A datatype D is defined by: A set L(D) of Unicode strings called the Lexical Space A set V(D) called the Value Space; A mapping L2V(D) : L(V) V(D), called the Lexical-to-value mapping, maps all Strings in the lexical space to a value in the value space. A Literal L with datatype D: In Turtle: "xxx"^^aaa, with: xxx is the Lexical Form aaa is the IRI that identifies datatype Da
e.g., Time dimension, Datatype for positions -> xsd:dateTime Datatype for distance -> xsd:duration L2V(xsd:dateTimeI)("2015-11-23T12:00:00Z" ) = L2V(xsd:dateTimeI)("2015-11-23T14:00:00+02:00") Time L(xsd:dateTimeI) L2V(xsd:durationI) L2V(xsd:dateTimeI) "P1Y" one year "2015-11-23T12:00:00Z" "PT0S" zero second "2015-11-23T14:00:00+02:00" "P1Y2M" 1 year, 2 months "blabla" L(xsd:dateTimeI)
What can I find when I look-up a IRI* ? http://dbpedia.org/resource/Tim_Berners-Lee * If I can look it up, it s obviously a URL (Locator): not a URN, not a literal (but maybe its datatype) 38
