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E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Interoperability and Semantic Technologies 2015-16An Introduction to the Semantic Web
Emanuele Della ValleDEIB - Politecnico di Milanohttp://emanueledellavalle.org - @manudellavalle
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
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To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/
Share, Remix, Reuse — Legally
2
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
IntroductionThe Web Today
3
Large number of integrations - ad hoc - pair-wise
Too much information to browse, need for searching and mashing up automatically
Each site is “understandable” for us
Computers don’t “understand” much
?
Search & Mash-up Engine
010 0 1 1 0
01101
10100 10 0010 01 101 101 01 110 1 10 110 0 1 1 01 0 1 0 0 1 1 0 1 1 1 10 01 101 0 1
Millions of Applications
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
IntroductionThe Problem: “Semantic Gap”
4
Sensor Data
Semantic Gap
Symbolic Description
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction “Understanding” Means Bridging the Gap
5
understanding
Sensor Data
Symbolic Description
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
IntroductionDo We Really Know What “Understanding” means?
6[ source http://www.thefarside.com/ ]
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
IntroductionTwo ways for computer to “understand”
7
Smart Data
Smart Machine
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Working examples found on the WebImage Processing
retrievr: find by sketching
http://labs.systemone.at/retrievr/ Audio Processing
midomi: find by singing
http://www.midomi.com/
[…]
Natural Language Processingsemantic proxy: http://semanticproxy.opencalais.com/about.html
IntroductionSmart Machines
8
Sensor Data
Symbolic DescriptionIm
age
Proc
essi
ng
Aud
ioPr
oces
sing
Nat
ural
Lan
guag
e
Proc
essi
ng
[…]
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Natural Language Processing (NLP) meets Image Processing (IP)
NLP: What does your eye see?IP : I see a seaNLP: You see a “c”?IP : Yes, what else could it be?
IntroductionSmart Machines alone cannot bridge the gap …
9
[Source NLP Related Entertainment http://www.cl.cam.ac.uk/Research/NL/amusement.html]
Sensor Data
Symbolic Description
Imag
e Pr
oces
sing
Nat
ural
Lan
guag
e
Proc
essi
ng
sea “c”
Semantic Gap
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Natural Language Processing (NLP) meets Image Processing (IP)
NLP: What does your eye see?IP : I see a wordnet:word-sea NLP: mmm, I see a wordnet:word-c IP : I believe we have different understanding of the world …NLP: So do I
Introduction… smart data are need
10
Sensor Data
Symbolic Description
Imag
e Pr
oces
sing
Nat
ural
Lan
guag
e
Proc
essi
ng
sea “c”
smart data
The Semantic Web offers a set of standards that lowers the barriers to
employ smart data at Web scale
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
What we say to Web agents " For more information visit <a
href=“http://www.ex.org”> my company </a> Web site. . .”
What they “hear” " blah blah blah blah blah <a
href=“http://www.ex.org”> blah blah blah </a> blah blah. . .”
Jet this is enought to train them to achive tasks for us
IntroductionWhat a machine “understands” of the Web
11[ source http://www.thefarside.com/ ]
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Understanding that[page1] links [page2] page2 is interesting
Google is able to rank results!“The heart of our software is PageRank™, a system for ranking
web pages […] (that) relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page's value.”
http://www.google.com/technology/
IntroductionWhat does Google “understand”?
12
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
“The Semantic Web is not a separate Web, but an extension of the current one, in which information is given well-defined meaning, better enabling computers and people to work in cooperation.”
“The Semantic Web”, Scientific American Magazine, Maggio 2001 http://www.sciam.com/article.cfm?articleID=00048144-10D2-1C70-84A9809EC588EF21
Key concepts• an extension of the current Web• in which information is given well-defined meaning • better enabling computers and people to work in
cooperation.• Both for computers and people
Introduction The Semantic Web 1/4
13
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
“The Semantic Web is not a separate Web, but an extension of the current one […] ”
Introduction The Semantic Web 2/4
14
Web 1.0 The Web Today
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
“The Semantic Web […] , in which information is given well-defined meaning […]”
Introduction The Semantic Web 3/4
15
Human understandable but “only” machine-
readable
Human and machine
“understandable”
?
Web 1.0 Semantic Web
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction The Semantic Web 4/4
16
Semantic Web
Fewer Integration - standard - multi-lateral
[…] better enabling computers and
people to work in cooperation.
Even More Applications
Easier to understand for people
More “understandable” for computers
Semantic Mash-ups &Search
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Linked Data Standards
17
View the full talk at http://www.ted.com/talks/view/id/484 !
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Goal: extend the Web with data commons by publishing open data sets using Semantic Web techs
Introduction Linking Open Data Project
Visit http://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenData !
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Example: BIO2RDF
19
Peter Ansell, Model and prototype for querying multiple linked scientific datasets, Future Generation Computer Systems, Volume 27, Issue 3, March 2011, Pages 329-333
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
• is an effort to add a spatial dimension to theSemantic Web.
• uses the information collected by the OpenStreetMap project
• makes it available as an RDF knowledge baseaccording to the Linked Data principles.
• interlinks this data with other knowledge bases in the Linking Open Data initiative.
Introduction Example: LinkedGeoData
20
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction data.gov and data.gov.uk
21
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction https://open-data.europa.eu/en/data
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
• Who: Richard MacManus • When: April 15th, 2010• Context: Modigliani’s painting are
scattered all other the world• The challenge: If all museums would have
published their collections as linked data, will it be possible to know the locations of allthe original paintings of Modigliani?
• http://readwrite.com/2010/04/15/the_modigliani_test_semantic_web_tipping_point
Introduction The Modigliani test for Linked Data
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
<?xml version="1.0" encoding="utf-8"?> <rdf:RDF xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs = "http://www.w3.org/2000/01/rdf-schema#" xmlns:owl = "http://www.w3.org/2002/07/owl#" xmlns:dc = "http://purl.org/dc/elements/1.1/" xmlns:foaf = "http://xmlns.com/foaf/0.1/" xmlns:rel = "http://www.perceive.net/schemas/relationship/" xmlns:mo = "http://purl.org/ontology/mo/" xmlns:rev = "http://purl.org/stuff/rev#" > <rdf:Description rdf:about="/music/artists/a3cb23fc-acd3-4ce0-8f36-
1e5aa6a18432.rdf"> <rdfs:label>Description of the artist U2</rdfs:label> <foaf:primaryTopic rdf:resource="/music/artists/a3cb23fc-acd3-4ce0-8f36-
1e5aa6a18432#artist"/> </rdf:Description> <mo:MusicGroup rdf:about="/music/artists/a3cb23fc-acd3-4ce0-8f36-
1e5aa6a18432#artist"> <foaf:name>U2</foaf:name> <owl:sameAs rdf:resource="http://dbpedia.org/resource/U2" /> <foaf:page rdf:resource="/music/artists/a3cb23fc-acd3-4ce0-8f36-
1e5aa6a18432.html" /> <mo:musicbrainz rdf:resource="http://musicbrainz.org/artist/a3cb23fc-acd3-
4ce0-8f36-1e5aa6a18432.html" /> <mo:homepage rdf:resource="http://www.u2.com/" /> <mo:fanpage rdf:resource="http://www.atu2.com/" /> <mo:wikipedia rdf:resource="http://en.wikipedia.org/wiki/U2" /> <mo:imdb rdf:resource="http://www.imdb.com/name/nm1277752/" /> <mo:myspace rdf:resource="http://www.myspace.com/u2" /> <mo:member rdf:resource="/music/artists/7f347782-eb14-40c3-98e2-
17b6e1bfe56c#artist" /> <mo:member rdf:resource="/music/artists/1f52af22-0207-40ac-9a15-
e5052bb670c2#artist" />
Introduction Example: BBC’s Artist as Linked Data
24
HTML: http://www.bbc.co.uk/music/artists/a3cb23fc-acd3-4ce0-8f36-1e5aa6a18432
RDF : http://www.bbc.co.uk/music/artists/a3cb23fc-acd3-4ce0-8f36-1e5aa6a18432.rdf DISCONTINUED
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
The Results of Modigliani test for Linked Data• Who: Atanas Kiryakov (Ontotext AD)• When: April 25th, 2010• How: http://factforge.net/ a “reason-able” view to the web of data• Results: http://bit.ly/ModiglianiTest
http://readwrite.com/2010/04/25/the_modigliani_test_for_linked_data
Introduction The Modigliani test for Linked Data
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
•Since Fall 2009•450.000 products •Using RDFa (= RDF embedded in HTML)•Pages with RDFa higher in Google ranking•BestBuy claims 30% more traffic!•Yahoo reports 15% higher click-through rat
Introduction Example: Best Buy
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
© 2012 Politecnico di Milano, Emanuele Della Valle
Introduction Example: Best Buy
<div rel="v:hasReview"><span property="v:rating" datatype="xsd:string"> 4.8</span> of <span property="v:best">5</span>
RDFa
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Google for Nikon+12.3-Megapixel+Digital+SLR+Camerahttps://www.google.com/search?q=Nikon+12.3-Megapixel+Digital+SLR+Camera
Introduction Example: Best Buy
enriche
d pages//28
Sponsored Links
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Use RDFa with some FB specific vocabularyog:title - The title of your object, e.g., "The Rock".og:type - The type of your object, e.g., "movie". og:image - An image URL og:url - The permanent ID of your object og:description - A one to two sentence description of your object.og:site_name - If your object is part of a larger web site, the name which
should be displayed for the overall site. e.g., "IMDb".
Introduction Example: Facebook Open Graph
http://ogp.me/
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Open Graph Usage Statistics15 millions sites are using Open Graph! 39% of the top 10,000 sites
Introduction Example: Facebook Open Graph
[Source: http://trends.builtwith.com/docinfo/Open-Graph-Protocol]
%
40
30
202010 2011 2012 2013 2014 2015
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Industrial uptake of Semantic markup
2009/2010 winter-2014
147.871.837 urls 620.151.400 urls microformats 80% rdfa+microdata 80%[Source: http://webdatacommons.org/structureddata/index.html#results-2013-1 ]
80%
20%
10%
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
RDFa, microformats and "rich snippet" on Google trends
Take home message: data formats matter, but data usage matters even more!
Introduction Usage matters!
microformats
RDFa
Rich snippet
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Usage matters! Yahoo! Search Monkey
[source https://developer.yahoo.com/searchmonkey/siteowner.html ]
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Usage matters! Google structured data
Emanuele Della Valle -
@manudellavalle - http://emanueledellavalle.
org
[source https://developers.google.com/structured-data/rich-snippets/ ]
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
• Schema.org• an initiative launched on 2 June 2011 by Bing, Google and Yahoo! • to “create and support a common set of schemas for structured data
markup on web pages.”• Like microformats it is a collection of vocabularies, but they are organized
in a broad type hierarchy (like RDF-Schema)• See http://schema.org/docs/full.html
• Initially schema.org introduced yet another type of semantic markup (i.e., microdata), but it stepped back and it now recommends either microdata or RDFa
• Tools are available: http://schema.rdfs.org/tools.html
Introduction schema.org
Emanuele Della Valle -
@manudellavalle - http://emanueledellavalle.
org
enriched pages//35
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
There are around 1200 types in the hierarchy
[Sou
rce
http
://bl
og.s
chem
a.or
g/20
15/1
1/sc
hem
aorg
-wha
ts-n
ew.h
tml ]
Introduction schema.org
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Beyond rich snippet, into the Knowledge Graph
Introduction schema.org
E. Della Valle – http://emanueledellavalle.org - @manudellavalle
Introduction Semantic Web “layer cake”
38
Standardized
UnderInvestigation
Already Possible
[ source http://www.w3.org/2007/03/layerCake.png ]