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Metadata is back!
Bernhard Haslhofer - Cornell University
JCDL 2011 - Semantic Web Technologies for Libraries and Readers WorkshopOttawa, CanadaThursday, June 16th 2011
<img src="catcher-in-the-rye-book-cover.jpg" />The Catcher in the Rye - Mass Market Paperbackby <a href="/author/jd_salinger.html">J.D. Salinger</a>
Price: $6.99In Stock
Product details224 pagesPublisher: Little, Brown, and Company - May 1, 1991Language: EnglishISBN-10: 0316769487
schema.org Book Example
<div itemscope itemtype="http://schema.org/Book">
<img itemprop="image" src="catcher-in-the-rye-book-cover.jpg"/><span itemprop="name">The Catcher in the Rye</span> - <link itemprop="bookFormat" href="http://schema.org/Paperback">Mass Market Paperback by <a itemprop="author" href="/author/jd_salinger.html">J.D. Salinger</a>
<div itemprop="offers" itemscope itemtype="http://schema.org/Offer">
Price: <span itemprop="price">$6.99</span> <meta itemprop="priceCurrency" content="USD" /> <link itemprop="availability" href="http://schema.org/InStock">In Stock<link itemprop=”url” href=”http://en.wikipedia.org/wiki/The_Catcher_in_the_Rye”></div>
...
</div>
schema.org Book Example
The story so far...
Library Catalogue
(c) Bill Steele/Cornell Chronicle
(c) Vienna University Library
(c) Vienna University Library
Identifier
Metadata
Controlled Vocabulary
OPAC
Identifier
Metadata
Controlled Vocabulary
WWW / Wikipedia / Search Engines
Metadata?
Identifier?
Controlled Vocabulary?
getMetadata(Web): void
Semantic Web - Early Vision
“The Semantic Web will bring structure to the meaningful content of Web pages, creating an environment where software agents roaming
from page to page can readily carry out sophisticated tasks for users”
“For the semantic web to function, computers must have access to structured collections of information and sets of inference rules that
they can use to conduct automated reasoning.”
"Mom needs to see a specialist and then has to have a series of physical therapy sessions.
Biweekly or something. I'm going to have my agent set up the appointments."
~2000 2011
Semantic Web Technologies
URI Unicode
XML
Data Model: RDF
RDF-S
Rules: RIFOntology:
OWLQuery: SPARQL
Unifying Logic
Proof
Crypto
Trust
User Interface & Applications
~2000 2011
RDFa & Microformats
• Mechanisms to embed structured metadata in Web pages
• Define and/or reuse (X)HTML attributes to augment information in Websites with machine-readable semantics
~2000 2011
RDFa Example
<div xmlns="http://www.w3.org/1999/xhtml" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:v="http://www.w3.org/2006/vcard/ns#"> <div about="http://example.com/me/behas" typeof="v:VCard"> <span property="v:fn">Bernhard Haslhofer</span> <span property="v:nickname">behas</span> <div rel="v:adr"> <div typeof="v:Address v:Work"> <span property="v:street-address">301 College Avenue</span> <span property="v:locality">Ithaca</span>, <span property="v:postal-code">14850</span>, <span property="v:country-name">United States</span>. </div> </div> <a rel="v:email" href="mailto:bernhard.haslhofer@cornell.edu">bernhard.haslhofer@cornell.edu</a>. </div></div>
~2000 2011
Microformats Example
<div class="vcard">
<span class="fn">Bernhard Haslhofer</span>
<div class="adr"><div class="street-address">301 College Avenue</div><span class="locality">Ithaca</span><span class="postal-code">14850</span><span class="country-name">United States</span>
</div>
<a class="email" href="mailto:bernhard.haslhofer@cornell.edu">bernhard.haslhofer@cornell.edu</a>
</div>
~2000 2011
• There is lots of information on the Web
• ... valuable information that can be (re-)used
• Problem• information is usually expressed in the form of HTML
documents
• the underlying raw data are locked in closed data silos (mostly DBMS)
Linked Data
~2000 2011
Why Linked Data?
• The Web is successful because it provides• Uniform encoding (HTML)
• Uniform addressing (URI)
• Uniform transportation (HTTP)
for the exchange of documents.
• Why not apply the same mechanism to the underlying data?
~2000 2011
What is Linked Data?
• A pragmatic method to build a Web of Data
• Architectural style based on SW standards
• Intelligent agents not primary focus
Web
~2000 2011
Publishing Data
• Distinguish between non-information and information resource
• Sample non-information resource• http://dbpedia.org/resource/The_Catcher_in_the_Rye
• Sample information resource• http://dbpedia.org/page/The_Catcher_in_the_Rye - HTML
• http://dbpedia.org/data/The_Catcher_in_the_Rye - RDF
~2000 2011
Retrieving Linked Data
~2000 2011
Microdata (HTML5)
• A very young HTML 5 proposition that extends Microformats and addresses its shortcomings
• Items are created within an itemscope
• Ever item is assigned an arbitrary number of properties (itemprop)
• Uses global identifiers for typing and naming items
~2000 2011
Microdata Example
<div itemscope itemtype="http://data-vocabulary.org/Person">
<span itemprop="name">Bernhard Haslhofer</span>, <span itemprop="nickname">behas</span>.
<div itemprop="address" itemscope itemtype="http://data-vocabulary.org/Address"><span itemprop="street-address">301 College Avenue</span><span itemprop="locality">Ithaca</span><span itemprop="country-name">United States</span>
</div>
</div>
~2000 2011
Google Rich Snippets / SEO
~2000 2011
~2000 2011
~2000 2011
schema.org
~2000 2011
~2000 2011
technical / conceptual complexity
RDFa
Microdata
URI Unicode
XML
Data Model: RDF
RDF-S
Rules: RIFOntology:
OWLQuery: SPARQL
Unifying Logic
Proof
Crypto
Trust
User Interface & Applications
Microformats
Where are we now?
(c) http://wiki.bib.uni-mannheim.de/dc-provenance/lib/exe/detail.php?id=europeana_example&media=europeana-ore.png
What next?
Deal with with schema.org
• Ignore it?
• Adopt it?
• Align existing library models with schema.org?
• Schema.org provides an extension mechanism for• properties
• classes
Data Quality / Resource Sync
• The Web is not static
• Resources and their representations might change or disappear over time
• Make sure that• applications can synchronize resources and learn about
changes
• go back in time
Use Web Data in Apps
• Aggregate Web resources into special collections
• DBpedia provides resource descriptions translated into 90+ languages!!!
• Use URIs instead of labels for tagging
• Combine and mesh up data
• Analyze data ...
Summary
Metadata is back
• Metadata was introduced in the 19th century to deal with the information overload
• Cataloguing rules and workflows evolved over time
• The Web seemed to work pretty well without metadata (info retrieval, nat.lang processing)
• Now we have strong indicators that structured metadata on the Web will play an important role in future
• Shouldn’t libraries / librarians be part of that?
References
• Coyle, K.: Library Data in a Modern Context. In: Understanding the Semantic Web: Bibliographic Data and Metadata. Library Technology Reports. January 2010
• http://blog.mediaspaces.info/ (Linked Data in Libraries State-of-the-Art)
BACKUP
Metadata Building Blocks
Metadata
Metadata Schema
Schema Definition Language
Title
Author
Genre
The Catcher in the Rye
Salinger, J.D.
Fiction (Digital / Non-Digital)Information Object
class
property
relationship
Title GenreAuthor
Google Rich Snippet Types
• Reviews
• People
• Products
• Businesses and organizations
• Recipes
• Events
~2000 2011
http://tripletalk.wordpress.com/2011/01/25/rdfa-deployment-across-the-web/
~2000 2011
cp.: http://evan.prodromou.name/RDFa_vs_microformats
Microformats RDFa
flat namespace XML namespaces
support HTML4, XHTML 1.1, and HTML 5 support for XHTML 1.1
use latent HTML attributes introduces new metadata attributes
vocabulary defined by one organization/community open to any RDF-based vocabulary
~2000 2011
Publishing Data
~2000 2011
GET http://dbpedia.org/resource/The_Catcher_in_the_RyeAccept: application/rdf+xml
303 See OtherLocation: http://dbpedia.org/data/The_Catcher_in_the_Rye
GET http://dbpedia.org/data/The_Catcher_in_the_RyeAccept: application/rdf+xml
200 OK...<?xml version="1.0" encoding="utf-8"?><rdf:RDF ...
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