Introduction to the Semantic Web - World Wide Web Consortium · 2008-10-06 · On the Way to the...

On the Way to the Semantic Web

Presented on Rio Info 2008 by Klaus Birkenbihl, Coordinator World Offices, W3C

based on a slide set mostly created by Ivan Herman, Semantic Web Activity Lead, W3C

Oct. 02nd, 2008

Copyright © 2008, W3C

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W3C?W3C?Launched 1993 by Web inventor Tim Berners-Lee (Director of W3C) to

Prevent the Web from breaking apartLead the Web to its full potential

Membership organisationMembers are big too small IT-Companies, user companies, Web organisations, standard bodies, research organisations and universities.~50 people on staff17 W3C Offices contribute as local representatives to international coverage of W3C (W3C.br is at NIC.br)

Develops the Web by providing (>100) technologies and standards e.g. (X)HTML, CSS, XML, ... (aka recommendations)

http://www.w3.org/2004/10/RecsFigure.png


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You may consider to meet W3C.br at the You may consider to meet W3C.br at the NIC.br booth to learn more about W3CNIC.br booth to learn more about W3C


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Some of you may have heard of itSo you might know already that it is hard stuff, complex and difficult to understandA thing that is only used in universities and researchIt uses a complex nearly unreadable XML vocabularySo you'd better not touch!Consequently I'd like to let you know ...

?


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... please forget it!... please forget it!Semantic Web is based on very simple principles – most of them are very much like what we know from the webSometimes Semantic Web lives within XML but this is only a Syntax – Semantic Web can exist mostly without XMLTechnologies are available and used in various waysSemantic Web is about making life in the Web easierSo you should know about it !


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What (approximately) I shall doWhat (approximately) I shall doUsing the web today

TravellingSocial networksCollecting and combining knowledge

Make some observationsLook for improvementsReuse Web concepts (URIs, Links, Resources)Suggest a solution that we call Semantic Web


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Let’s organize a trip to Budapest using the Let’s organize a trip to Budapest using the Web!Web!


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You try to find a proper flight with …You try to find a proper flight with …


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… … a big, reputable airline, or …a big, reputable airline, or …


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… … the airline of the target country, or …the airline of the target country, or …


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… … or a low cost oneor a low cost one


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You have to find a hotel, so you look for…You have to find a hotel, so you look for…


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… … a really cheap accommodation, or …a really cheap accommodation, or …


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… … or a really luxurious one, or …or a really luxurious one, or …


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… … and intermediate one …and intermediate one …


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oops, that is no good, the page is in oops, that is no good, the page is in Hungarian that almost nobody Hungarian that almost nobody

understands, but…understands, but…


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… … this one could workthis one could work


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Of course, you could decide to trust a Of course, you could decide to trust a specialized site…specialized site…


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… … like this one, or…like this one, or…


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… … or this oneor this one


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You may want to know something about You may want to know something about Budapest; look for some photographs…Budapest; look for some photographs…


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… … on flickr …on flickr …


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… … on Google …on Google …


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… … or you can look at Ivan's or you can look at Ivan's


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but you can also look at a (social) travel sitebut you can also look at a (social) travel site


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What happened here?What happened here?You had to consult a large number of sites, all different in style, purpose, possibly language…You had to mentally integrate all those information to achieve your goalsWe all know that, sometimes, this is a long and tedious process!


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All those pages are only tips of respective icebergs:the real data is hidden somewhere in databases, XML files, Excel sheets, …you have only access to what the Web page designers allow you to see

Specialized sites (Expedia, TripAdvisor) do a bit more:

they gather and combine data from other sources (usually with the approval of the data owners)but they still control how you see those sources


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Sometimes you want more: you may want access to the original data and combine it yourself!


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Here is another example…Here is another example…


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Companies may have to hire a person to answer questions based on those (public!) databases!


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Another example: social sites. Ivan has a Another example: social sites. Ivan has a list of “friends” by…list of “friends” by…


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… … Dopplr, Dopplr,


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… … Twine,Twine,


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… … LinkedIn,LinkedIn,


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… … and, of course, the ubiquitous Facebookand, of course, the ubiquitous Facebook


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He had to type in and connect with friends again and again for each site independentlyThis is even worse then before: he feeds the icebergs, but he still does not have an easy access to data…


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What would we like to have?What would we like to have?Use the data on the Web the same way as we do with documents:

be able to link to data (independently of their presentation)use that data the way I want (present it, mine it, etc.)agents, programs, scripts, etc. should possibly be able to interpret part of that data

This does not mean you have to do these presentations, scripts ... but it would provoke ideas and applications that make better use of existing data“The bane of my existence is to do things that my computer could do for me” — Dan Connolly


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Put it another way…Put it another way…We would like to extend the current Web with a “Web of data”:

allow for applications to exploit the data directly


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But wait! Isn’t this what mash-up sites are But wait! Isn’t this what mash-up sites are already doing?already doing?


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Example: Klaus' trip to Brazil (tripit.com)Example: Klaus' trip to Brazil (tripit.com)


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How does it workHow does it workKlaus forwards to Tripit the documents (mails, URIs) I have wrt a trip. e.g.

Flight bookingsHotel reservationsMeetings

Any time he has new documents he may add them

Tripit tries to extract the relevant data from these documentsIt associates the documents to a tripIt add information from other sites about weather, directions, travel guides ...It checks its own database for travel activities of friendsIt compiles a structured itinerary


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This is great ... butThis is great ... butSometimes Tripit sends Klaus a message “Problem with your TripIt submission”Sometimes some data from a document are not identifiedSometimes Klaus reads: “Please help us to improve! Let us know how good we captured your flight.”This is a hint on what Tripit does: in case it does not know how to find the data it has to guessBecause there is no standardized way to access the data it has to use proprietary interfaces to get them.


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So in some ways, this shows the huge power of what a Web of data providesBut mash-up sites are forced to do very ad-hoc jobs

various data sources expose their data via Web Serviceseach with a different API, a different logic, different structurethese sites are forced to reinvent the wheel many times because they don't use a standard way of doing things


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Put it another way (again)…Put it another way (again)…We would like to extend to the current Web with a standard way for a “Web of data”


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But what does this mean? But what does this mean?

What makes the current (document) Web work?people create different documentsthey give an globally unique address to it (i.e. a URI) and make it accessible to others on the Web


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An example: Steven’s site on AmsterdamAn example: Steven’s site on Amsterdam


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Then some magic happens…Then some magic happens…Others discover the site and they link to it

So Search engines can find it and index itThe more they link to it, the more important and well known the page becomes

remember, this is one criterion, Search engines use to rank pages.

This is the “Network effect”: some pages become important, and others begin to rely on it (even if the author did not expect it…)


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This link to Steven’s is, sort of, This link to Steven’s is, sort of, understandable…understandable…


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… … but this one is on the other side of the but this one is on the other side of the Globe!Globe!


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What would that mean for a Web of Data?What would that mean for a Web of Data?Lessons learnt: we should be able to:

“publish” the data to make it known on the Web standard ways should be used instead of ad-hoc approaches the analogous approach to documents: give URI-s to the data

make it possible to “link” to that URI from other sources of data (not only Web pages) using standard approaches

ie, applications should not be forced to make targeted developments to access the data (as we saw with mash-ups)

generic, standard approaches should suffice and let the network effect work its way…


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Example: combine data from experimentsExample: combine data from experimentsA drug company has huge amount of old experimental data on its IntranetData in different formats (XML, databases, …)

Courtesy of Nigel Wilkinson, Lee Harland, Pfizer Ltd, Melliyal Annamalai, Oracle (SWEO Case Study)

To reuse them:make the important facts available on the Web via standardsuse off-the-shelf tool to integrate, display, search

http://www.w3.org/2001/sw/sweo/public/UseCases/Pfizer/


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But it is a little bit more complicatedBut it is a little bit more complicatedOn the traditional Web, humans are implicitly taken into accountA Web link has a “context” that a person may use


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Eg: public encryption key on Ivan's page:Eg: public encryption key on Ivan's page:


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Eg: public encryption key on Ivan's page:Eg: public encryption key on Ivan's page:


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Humans can interpret labels ...Humans can interpret labels ...A human understands that this is Ivan's encryption key (it is in the text!)She knows what she can do with it (e.g. add it to her keyring). Therefore to label a link “click here” is a usability and accessibility clash in most cases.

On a Web of Data, something is missing; machines can make no sense of that link alone


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extra information (“label”) must be added to a link: “this links to a GnuPG public key”. this information should be machine readablethis is a characterization (or “classification”) of both the link and its targetin some cases, the classification should allow for some limited “reasoning”

So for the Web of data ...So for the Web of data ...


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Let us put togetherLet us put togetherwhat we need for a Web of Datawhat we need for a Web of Data

URI-s to publish data, not only full documentsdata can to link to other datathe data and the links (the “terms”) should be characterized/classified to convey some extra meaning standards for all these to maintain interoperability


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Example: find the right experts at NASAExample: find the right experts at NASA

NASA has nearly 70,000 civil servants over the whole of the USTheir expertise is described in 6-7 databases, geographically distributed, with different data formats, access types…Task: find the right expert for a specific task within NASA!

Michael Grove, Clark & Parsia, LLC, and Andrew Schain, NASA, (SWEO Case Study)

http://www.w3.org/2001/sw/sweo/public/UseCases/Nasa/


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Example: find the right experts at NASAExample: find the right experts at NASAApproach: integrate all the data with standard means, and describe the data and links using generic vocabularies

Michael Grove, Clark & Parsia, LLC, and Andrew Schain, NASA, (SWEO Case Study)

http://www.w3.org/2001/sw/sweo/public/UseCases/Nasa/


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So What So What isis the Semantic Web? the Semantic Web?


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It is a collection of standard technologies It is a collection of standard technologies to realize a Web of Datato realize a Web of Data


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a common model has to be provided for machines to understand the “labels” and draw some conclusions from that infothe “classification” of the terms can become very complex for specific knowledge areas: this is where ontologies, thesauri, vocabularies, etc, enter the game…

It is that simple…It is that simple…but of f course, the devil is in the detailsbut of f course, the devil is in the details


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Example: eTourism in ZaragozaExample: eTourism in Zaragoza

Provide personalized itinerary serviceIntegration of different databases in Zaragoza (using targeted ontologies)Use rules on the data to provide a proper itinerary

Courtesy of Jesús Fernández, Municipality of Zaragoza, and Antonio Campos, CTIC (SWEO Use Case)

http://www.w3.org/2001/sw/sweo/public/UseCases/Zaragoza-2/


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Wait! Does it mean that you have to Wait! Does it mean that you have to convert all your data in some way?convert all your data in some way?


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Not necessarily; this would not always be feasibleThere are technologies to make your data accessible to standard means without converting it

run-time “bridges” (e.g. rewriting queries on the fly)generate only entry points in separate datasetsannotate existing data (e.g. XHTML pages)etc

Convert your data?Convert your data?


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Example: integrate knowledge for Chinese Example: integrate knowledge for Chinese MedicineMedicine

Integration of a large number of TCM databases around 80 databases, around 200,000 records each

Uses specialized ontologiesQueries are converted on-the-fly to the databases

Courtesy of Huajun Chen, Zhejiang University, (SWEO Case Study)

http://www.w3.org/2001/sw/sweo/public/UseCases/UniZheijang/


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In the end ...In the end ...There is a huge potential for useful applications once we have a web of dataMash-ups give good examples for applications based on linking dataWhen (re)designing a web site some thoughts on publishing data along with the documents might pay in the future.


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Slides are available at:http://www.w3.org/2008/Talks/1002RioDeJaneiro-KB-IH/in OpenDocument Presentation Format and PDF.

Questions? Thank you for your attention!

http://www.w3.org/2008/Talks/1002RioDeJaneiro-KB-IH/

http://www.w3.org/2008/Talks/1002RioDeJaneiro-KB-IH/slides.odp

http://www.w3.org/2008/Talks/1002RioDeJaneiro-KB-IH/slides.pdf

Introduction to the Semantic Web - World Wide Web Consortium · 2008-10-06 · On the Way to the...

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