1. Venkata Krishna Potta and Ketan Reddy Peddabachi
OAI-ORE
Venkata Krishna Potta
and
Ketan Reddy Peddabachi
Instructor:
Dr. Michael Nelson
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2. Presentation Overview
Introduction
The ORE Model
Resource Map Implementation in Atom
ReM Demo
Discovery of ReM’s
Conclusion
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3. OAI –Open Archive Initiative
Initially OAI started with an effort to enhance access to e-print archives as a means of increasing the availability of scholarly communication
Now opening up access to a range of digital materials.
Major Projects: OAI-ORE and OAI-PMH
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4. Open Archives Initiative-Object Reuse and Exchange (OAI-ORE)
OAI-ORE defines standards for the description and exchange of aggregations of Web resources. Reference
ORE will develop specifications that
allow distributed repositories to exchange information about their constituent digital objects.
will include approaches for representing digital objects and repository services that facilitate access and ingest of these representations.
will enable a new generation of cross-repository services that leverage the intrinsic value of digital objects beyond the borders of hosting repositories.
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5. CS 791/891 "Web Syndication Formats"
Terms
Resources - refers to any item of interest found on the web.
Aggregation- a collection of related resources.
Aggregated Resource- resource which is part of an aggregation
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6. Examples of Aggregations:
A collection of favorite images from various Web sites.
My Images
A blog consisting of related images and videos.
cnn blog
A multi-page, HTML document where the pages are linked together by hyperlinks that provide "previous page" and "next page" access.
HTML Pages
Information available from "social networking" sites, such as flickr, YouTube, and myspace.
Photos
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7. Aggregation and Aggregated resources
The Web :
Reference
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8. Aggregation and Aggregated resources
ReM
Resource
Aggregated Resource
Aggregation
Reference
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9. CS 791/891 "Web Syndication Formats"
The ORE Model
Resource Map (ReM)
A Resource that specifies a URI for an Aggregation
Enumerates the constituents of Aggregation
Describes the relationships among them
Identification of a Resource Map (URI-R)
Identification of an Aggregation (URI-A)
fragment identifier
dereference of URI-R.
Example: the URI-R
Aggregation with URI-A
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10. CS 791/891 "Web Syndication Formats"
ReM Graph
Reference
Add reference
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11. CS 791/891 "Web Syndication Formats"
ReM-Aggregation
Reference
Add reference
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12. Representing Metadata
Reference
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13. CS 791/891 "Web Syndication Formats"
Aggregated Resources
Reference
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14. Sharing of Aggregated Resources
Reference
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15. Serialization Formats
The ORE Model can be implemented many serialization formats, 2 of them being:
Atom
RDF/XML
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16. CS 791/891 "Web Syndication Formats"
    Resource Map Implementation in Atom
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17. CS 791/891 "Web Syndication Formats"
Building a ReM
arXiv eprint example:
Hypothetical ReM
3 Aggregated Resources
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18. CS 791/891 "Web Syndication Formats"
Building a ReM…
<?xml version="1.0" encoding="utf-8"?> <feed xmlns=" <id>tag:arxiv.org,2007:astro-ph/ v2</id>
<category scheme=" term=" label="Resource Map" />
<link rel="describes" href=" />
<entry> <id>tag:arxiv.org,2007:astro-ph/ v2:pdf</id> </entry>
<entry> <id>tag:arxiv.org,2007:astro-ph/ v2:ps</id> </entry>
<entry> <id>tag:arxiv.org,2007:astro-ph/ v2:e-print</id> </entry>
</feed>
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19. CS 791/891 "Web Syndication Formats"
Building a ReM…
<?xml version="1.0" encoding="utf-8"?> <feed xmlns="
<id>tag:arxiv.org,2007:astro-ph/ v2</id>
<link href=" rel="self" type="application/atom+xml"/>
<category scheme=" term=" label="Resource Map" />
<link rel="describes" href=" />
<entry> <id>tag:arxiv.org,2007:astro-ph/ v2:ps</id>
<link href=" rel="alternate" type="application/postscript"/> </entry> ….
</feed>
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20. CS 791/891 "Web Syndication Formats"
Building a ReM…
More Elements:
/feed/title
/feed/entry/title
/feed/author
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21. CS 791/891 "Web Syndication Formats"
Building a ReM…
/feed/updated and
/feed/entry/updated
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22. Common Scenarios for Aggregations
Multiple Formats
Mirror Copies
Versions
Splash Pages
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23. Resource Map Discovery
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24. Resource Map Discovery
Crawlers or harvesters must discover Resource Maps (ReMs).
Different discovery mechanisms :
(A) Batch Discovery,
(B) Resource Embedding &
(C) Response Embedding
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25. CS 791/891 "Web Syndication Formats"
(A) Batch Discovery
In this method agents can discover ReMs in groups.
ReMs are represented in many formats, batch discovery can be applied to most of those ReMs
i) ReMs in OAI-PMH
ii) ReMs in SiteMaps
iii) ReMs in Syndication Feeds
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26. CS 791/891 "Web Syndication Formats"
i)ReMs in OAI-PMH
OAI-PMH Request:
<?xml version="1.0" encoding="UTF-8"?>
<OAI-PMH xmlns=
xmlns:xsi=
xsi:schemaLocation="
<responseDate> T08:55:46Z</responseDate>
<request verb="GetRecord" identifier="oai:foo.edu:object1"
metadataPrefix="oai_rem">
<GetRecord>
<record>
<header>
<identifier>oai:foo.edu:object1</identifier>
<datestamp> </datestamp>
</header>
<metadata>
<!-- Insert ReM here -->
</metadata>
</record>
</GetRecord>
</OAI-PMH>
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27. CS 791/891 "Web Syndication Formats"
ii) ReMs in SiteMaps
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="
<url>
<loc>
<lastmod> </lastmod>
</url>
<loc>
<lastmod> </lastmod>
<changefreq>weekly</changefreq>
<loc>
<lastmod> T18:30:02Z</lastmod>
<priority>0.3</priority>
...
</urlset>
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28. iii) ReMs in Syndication Feeds (Atom)
<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="
<title>ReMs at
<link href=" />
<link href=" rel="self"/>
<updated> T18:30:02Z</updated>
<author>
<name>John Doe</name>
</author>
<id>urn:uuid:60a76c80-d399-11d9-b91C e0af6</id>
<entry>
<title>ReM For Object1</title>
<link href="
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated> T00:00:00Z</updated>
</entry>
<title>ReM For Object2</title>
<link href="
<id>urn:uuid:9a2cc699-ccba-9e8b-132e-91da394e9a5c</id>
<updated> T00:00:00Z</updated>
</feed>
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29. iii) ReMs in Syndication Feeds (RSS 2.0)
<?xml version="1.0"?>
<rss version="2.0">
<channel>
<title>ReMs at
<link>
<description>All of the Resource Maps for resources at
<item>
<title>ReM for Object 1</title>
<link>
<description>ReM for Object 1</description>
<pubDate>Sat, 06 Jan :00:00 GMT</pubDate>
</item>
<title>ReM for Object 2</title>
<link>
<description>ReM for Object 2</description>
<pubDate>Sat, 11 Aug :00:00 GMT</pubDate>
</channel>
</rss>
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30. (B) Resource Embedding
The link to the ReM is embedded into the webpage.
Can be done using
i) HTML Link Element
ii) Showing ReMs in HTML pages.
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31. CS 791/891 "Web Syndication Formats"
Knowledge Levels
Full knowledge
the ReM is linked to by all resources in the aggregation.
Indirect knowledge
all but one of the resources in the aggregation link to a single,unique resource in the aggregation, which in turn links to the ReM.
functionally the same as full knowledge, but likely to be useful in actual deployment
Limited knowledge
only a subset of the resources in the aggregation (typically just a single resource) link to the ReM, and the remainder of the resources have no links at all.
Zero knowledge
none of the resources in the aggregation link to a ReM.
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32. i) HTML Link Element (Full Knowledge)
<head>
<title>Hello World.</title>
<link href=" type="application/atom+xml"
rel="resourcemap" >
</head>
<body>
<img src="hello.jpeg">
<img src="world.jpeg">
</body>
</html>
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33. ii) HTML Link Element (Indirect Knowledge)
<head>
<title>Chapter Twelve.</title>
<link href=" type="text/html"
rel="indirectresourcemap" >
</head>
<body> Welcome to chapter twelve... </body>
</html>
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34. ii) Showing ReMs in HTML pages
Link to the ReM
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35. (C) Response Embedding
The HTTP response has the link to the ReM.
(request):
HEAD HTTP/1.1
Host:
Connection: close
(response):
HTTP/ OK
Date: Sat, 26 May :43:10 GMT
Server: Apache/2.2.0
Last-Modified: Sat, 26 May :32:04 GMT
ETag: "c "
Accept-Ranges: bytes
Content-Length: 2070
Link: < type="application/atom+xml"; rel="resourcemap"
Content-Type: image/jpeg
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36. CS 791/891 "Web Syndication Formats"
References
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