Talk delivered during the Makolab Semantic Day 2013.

1. The importance of the Web for the
Semantic Web
Alexandre Monnin, PhD
Associate researcher @Inria
Senior Open data Adviser for Etalab
Chair of the « PhiloWeb » community group (W3C)
Organiser of the « Les rencontres du web de données » Meetup
Twitter: @aamonnz/@PhiloWeb, Website : web-and-philosophy.org

2. “semantic web”
and not
“semanticweb”
[C. Welty, ISWC 2007]
Above all: the Semantic Web is deeply
entrenched in the Web

3. Why the Web?
LeslieCarr,«TheFundamentalsoftheWeb,the
ImportanceofWebScience”
«

4. Maybe it is a « temporary glitch? »
(Leslie Carr)
A fragile reality, relying on specific architectural
principles, that gave birth over the years to many
innovations that may threaten its very existence.
If the Semantic Web (or Web of data) has any
future, it must be aware of its roots and preserve
what made the Web so incredibly successful on a
previously unseen scale.

5. I. Naming/identifying

6. The basics
Kieron O’Hara, « The Web as an ethical space »

7. Three components of the architecture of
the web
• identification (URI) & « adressability » (URL)
http://www.inria.fr
http://ns.inria.fr/fabien.gandon#me
ldap://[2001:db8::7]/c=GB?objectClass?one
• communication / protocol (HTTP)
GET /centre/sophia HTTP/1.1
Host: www.inria.fr
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; de-de)
AppleWebKit/523.10.3 (KHTML, like Gecko) Version/3.0.4
Safari/523.10
Accept-Encoding: gzip
Accept: text/html,application/xhtml+xml,application/xml
Accept-Language: en,en-us;q=0.8,fr;q=0.5,fr-fr;q=0.3
Accept-Charset: ISO-8859-1,UTF-8;q=0.7,*;q=0.7
Referer: http://fabien.info/
• Representation(s) languages (HTML / RDF)
Fabien travaille chez <a href="http://www.inria.fr">Inria</a>
<http://www.inria.fr> foaf:member data:fabien

8. Three functions
• identification of ressources (URI)
• access to representation (HTTP URI)
• Encoding of representations (HTML , RDF, etc)

9. URIs (universal syntax)
Because the Web had to link to other competing
systems: WAIS, Gopher, Prospero…
Interoperability and openneness gave it a decisive
advantage from the inception (Google “Gopher”!).

10. “I originally called these things “Universal Document
Identifiers” (UDIs) even before we started using them
for concepts. 8 The IETF were a bit put off, thinking it
was too much hubris to call them “universal.”
Now I realize that I should have held firm and said
“but they are,” as any alternative system of naming
you can make out there, I can map it to the character
set we use in URIs and I can invent a new scheme for
it. So we can map any scheme to URIs. We’d already
mapped Gopher, FTP, and these sorts of things. Now,
we’ve got HTTP and there will be lots of other
schemes. So in a sense URIs are universal, as we’re
saying anything—any name that you come across—
can be mapped into this space.” –TimBL)

11. URIs are also what…
URIs: not « just » a universal syntax

12. http://www.
…links…

13. …(yes, links!)…

14. are made of
<a href=“http://example.com/”>lorem ipsum</a>

15. This remains
true of the
Semantic Web
as well

16. le web originel
liens typés…

17. RDF every bit of information is decomposed in
triples
Subject / entity /node
relation /attribute/arc
object / value /node

18. ex :
Slides.html has for author Alexandre
and for theme the Web

19. Slides.html has author Alex
Slides.html has theme Web

20. Semantic web
Mentioned by Tim BL
in 1994 at WWW
[Tim Berners-Lee 1994, http://www.w3.org/Talks/WWW94Tim/]

21. « From ADA to AAA »
• ADA (Web) = Anyone can designate anything
“philosophy may be necessary to explain what
happens when the legal system hits the Web. When
you make a web-page you can link to anything, you
can write anything about it. But when a lawyer comes
along and reserves the right to charge you to link to
their page, then in a way it’s a philosophical question,
as you have to tie linking to the way the protocol is
defined over a name as just a reference,
something that has never been controlled over the
millennia. Systems where you control names haven’t
worked so far, and so you need the philosophy to
show how these protocols are ground out in history
and in concepts for using names that lawyers” (TimBL)

22. « From ADA to AAA »
• AAA (Linked data) = Anyone can say anything
about anything
Because we can
designate anything
(green lines), we
can then link any
things (red lines)

23. II. What’s being named?
ressources

24. Document Properties Correlate
UDI Papers (1992)
logical name, not a physical address so
that moving documents does not
impinges on the durability of such
names (some details should be
obfuscated)
object or document, unit of retrieval
rather than the unit of storage, might
identify a query formulated through a
service, a question rather than a
document
URI RFC 1630 (1994)
cf. above. Distinct from a file name
that is local, should remain opaque,
devoid of the details attached to the
technicalities of its implementation
accessible objects if URIs are also URLs
URL RFC 1738 (1994) non-physical address
resources (not defined), identified in a
abstract way (by contrast, accessible
contents for RFC 1739)
URN
RFC 1737
(1994)
name, identifier stable resource, not accessible
IRL
RFC 1736
(1995)
address (URL), Identifier (URN),
Description (URC)
resource – networked or non-
networked
URC IETF drafts meta-information, list of identifiers – Document

25. 
appearences database
One URI never = one « page »
Electronic
documents
Rendering
service
Computers
Servicing
Client
Application
Other encoding
formats
RPC
Psychophysically
equivalents
client server
Content negotiation (conneg)
http
A forerunner: system 33 (1991-1993)

26. HTTP Range 14
Code HTTP Résultat Indication
200 (OK) Representation
Information ressource or non-
information resources
303 (see
other)
URI Any kind of resource
4XX, 5XX
(error)
Error message Nothing can be inferred
They did not talk about it They talked about it

27.  ressource
 state de of the resource
 the representational state of the
resource (whence the acronym
« REST »!)
 Actually, this explains why there are no links on the Web before an actor like Google
appears. Links are indeed rather pointers to resources inside the representations of other
ressources (and, as such, these pointer might not dereference, nor therefore link two
relata).
Wait! How about REST?
« »

28. "Resources are
angels,
URIs pins"
"Naming is printing money"
(Larry Masinter)

29. Resources are « shadows »: not a bug
but one of the Web’s greatest features
“7.1.2 Manipulating Shadows. Defining resource such that
a URI identifies a concept rather than a document leaves
us with another question: how does a user access,
manipulate, or transfer a concept such that they can get
something useful when a hypertext link is selected? REST
answers that question by defining the things that are
manipulated to be representations of the identified
resource, rather than the resource itself. An origin server
maintains a mapping from resource identifiers to the set
of representations corresponding to each resource. A
resource is therefore manipulated by transferring
representations through the generic interface defined by
the resource identifier.” (Roy Fielding)

30. Can objects be mere « shadows » ?
Not « mere » shadows, but still, that compares well to what some
philosophershave to say about objects:
“the presence of an object inherently involves its absence. The reason is
simply the standard one: in order for a subject to take an object as an
object, there must be a separation between them – enough separation to
make room for intrinsic abstraction, of detachment, of stabilization. So it is
essentially an ontological theorem of this metaphysics that no object, for any
given subject, will be wholly there, in the sense of being fully effectively
accessible. Or, to put it more carefully: in order to be present ontologically – i.e.,
in order to be materially present – an object must also be (at least partially)
absent metaphysically, in the sense of being partly out of effective reach.”
(Brian Cantwell Smith)
 Just as an objet is never entirely present, a resource is never accessed as
such, only « representations » are – slices of trajectories. Many philosophers
thus argue that objects are not already there, waiting to be picked up or
designated. Rather, what we designate are regularities, patterns that need to
be tended to and maintained and that call for it.

31. It comes with a price
The trajectory drawn by these regularities corresponds to
Justin Erenkranz’ characterization of resource as “network
continuation”.
The price is higher than expected since identifying ressource
necessitates to "maintain a mapping from resource identifiers
to the set of representations corresponding to each resource".
 The cost is so high that, eventually, everything will be 404.
404 guarantee that no higher authority is responsible for
making sure that every URI dereferences. It is as much a
design principle of the Web as any other.

32. May 2007
April 2008
September 2008 March 2009
September 2010
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
September 2011
The Web as ontology
On what there is on a global scale

33. September 2011
From ADA and AAA to a shared world:
Wikipedia and DBpedia

35. Conclusion :
• “The Web may fragment if the engineering isn’t
right” (Kireon O’Hara)
• Just as the Web is an application built on the
Internet, not the Internet, applications built on
the Web are not the Web itself. While they might
depart from its principles, yet they build on its
success.
• “The Web spreads the conditions of its initial
creation” (L. Carr). Then, as an open platform, it
also spreads potential threats to these
conditions.

36. Why should we care for the Web?
• While many important players are all trying to impose
their own rules, keeping data behind closed walls, silos,
proprietary platforms, we can see one of them going
against the grain, towards more and more openness,
building a platform designed to nurture open
innovation: Valve’s Steam in the field of video games.
• “So rather than having this curated store we’re going to
say, “OK if we are thinking about this correctly, it really
should be sort of a network API.” There should be this
publishing model – and yes you have to worry about
viruses and malware and stuff like that – but essentially
anybody should be able to publish anything through
Steam.” (Gabe Newell)
• No unlike the Web…

37. Thank you very much!