Metadata is back!
Bernhard Haslhofer - Cornell University
JCDL 2011 - Semantic Web Technologies for Libraries and Readers Workshop
Ottawa, Canada
Thursday, June 16th 2011

schema.org Book Example
<img src="catcher-in-the-rye-book-cover.jpg" />
The Catcher in the Rye - Mass Market Paperback
by <a href="/author/jd_salinger.html">J.D. Salinger</a>
Price: $6.99
In Stock
Product details
224 pages
Publisher: Little, Brown, and Company - May 1, 1991
Language: English
ISBN-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>

The story so far...

Library Catalogue
Controlled
Vocabulary
(c) Vienna University Library
Metadata
(c) Bill Steele/Cornell Chronicle
Identifier
(c) Vienna University Library

OPAC
Metadata
Controlled
Vocabulary
Identifier

WWW / Wikipedia / Search Engines
Identifier?
Metadata?
Controlled Vocabulary?

getMetadata(Web): void

Semantic Web - Early Vision
"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."
“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.”
~2000 2011

Semantic Web Technologies
User Interface & Applications
Trust
Proof
Unifying Logic
Ontology:
Rules: RIF
Query: OWL
SPARQL
RDF-S Crypto
Data Model: RDF
XML
URI Unicode
~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

Linked Data
• 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)
~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

Facebook
~2000 2011

Facebook
~2000 2011

schema.org
~2000 2011

technical /
conceptual
complexity
User Interface & Applications
Trust
Proof
Unifying Logic
Ontology:
Rules: RIF
Query: OWL
SPARQL
RDF-S Crypto
Data Model: RDF
XML
URI Unicode
RDFa
Microdata
Microformats
~2000 2011

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
class relationship
Schema Definition
Language
property
Metadata Schema
Title Author Genre
Title The Catcher in the Rye
Metadata Author Salinger, J.D.
Genre Fiction (Digital / Non-Digital)
Information Object

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/

Facebook
~2000 2011

Microformats RDFa
flat namespace XML namespaces
support HTML4, XHTML 1.1, and
support for XHTML 1.1
HTML 5
use latent HTML attributes introduces new metadata attributes
vocabulary defined by one
open to any RDF-based vocabulary
organization/community
cp.: http://evan.prodromou.name/RDFa_vs_microformats
~2000 2011

Publishing Data
GET http://dbpedia.org/resource/The_Catcher_in_the_Rye
Accept: application/rdf+xml
303 See Other
Location: http://dbpedia.org/data/The_Catcher_in_the_Rye
GET http://dbpedia.org/data/The_Catcher_in_the_Rye
Accept: application/rdf+xml
200 OK
...
<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF ...
~2000 2011