Transcript A Web-Based Resource Model for eScience

A Web-Based Resource Model for
eScience:
Object Reuse & Exchange
2008 Microsoft eScience Conference
Indianapolis, December 8, 2008
OAI-ORE Editors
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Carl Lagoze
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Cornell University
Herbert Van de Sompel
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Los Alamos National Laboratory
Pete Johnston
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Eduserv Foundation
Michael Nelson
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Old Dominion University
Rob Sanderson
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University of Liverpool
Simeon Warner
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Cornell University
Joint work with …
ORE Technica l Committee
Chris Bizer
Les Carr
Tim DiLauro
Leigh Dodds
David Fulker
Tony Hammond
Pete Johnston
Richard Jones
Carl Lagoze
Peter Murra y
Michael Nelson
Ray Plante
Rob Sanderson
Herbert Van de Sompel
Sim eon Warner
Jeff Young
Freie UniversitŠt Berli n
University of Southampton
Johns Hopkins University
Ingenta
UCAR
Nature Publishing Group
Eduser v Foundation
HP Labs
Cornell University
OhioLINK
Old Dominion University
NCSA and National Virtual Observatory
University of Liverpool
Los Alamos National Laboratory
Cornell University
OCLC
ORE Liaison G roup
Leonardo Candela
Tim Cole
Juli e Alli nson
Jane Hunter
Savas Parastatidis
Sandy Payette
Thomas Place
Andy Powell
Robert Tansley
Consigli o Nazionale dell e Ricerche - DRIVER
University of Illi nois Urbana-Champaign - Aquifer
JISC
University of Queensland - DEST
Microsoft Corporation
Fedora Commons
University of Tilburg - DARE
Eduser v Foundation - DCMI
Google, Inc. - DSpace
OAI Object Reuse and Exchange: Support
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The Andrew W. Mellon Foundation
The Coalition for Networked Information
Joint Information Systems Committee
Microsoft Corporation
The National Science Foundation
OAI Object Reuse and Exchange
Subject: Aggregations of Web resources
Approach: Publish Resource Maps to the Web that
Instantiate, Describe, and Identify Aggregations
Aggregations
Instantiate, Describe, and Identify
Aggregations
Aggregations
At one time it was possible to convey all
scientific information about a topic in a
single “convenient” medium.
Babylonian Astronomical Catalogue
Aggregations
But quickly the limitations of that medium
became obvious.
1857 Astrophysics paper
text
data
Aggregations
Those limitations
seem to live on.
Aggregations
“Solving” the problem with ad hoc
methods.
1890 Astrophysics paper
Photo plate kept separate from text
(digitized version of original plate shown)
text
Aggregations
2006 Astrophysics paper
Objects of interest in eScience are by
nature compound.
X-MM-Newton X-ray observation
Vilspa, Spain
Chandra X-ray observation
Cambridge, MA
A1795
Basic object information
Strasbourg, France
text
Hubble optical observation
Baltimore, MD
Splash page
Aggregations!
Formats
Relationships
Identifiers
Versions
http://arxiv.org/abs/astro-ph/0611775
Object Reuse and Exchange: A Web-Centric Approach
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The Web Architecture as the platform for
interoperability
De-facto integration with existing Web
applications
Potential of adoption by other
communities
Potential of tools created by other
communities
Incorporating the “social web” (Web 2.0)
in eScience
Foundations of OAI-ORE
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Web Architecture
- <http://www.w3.org/TR/webarch/>
Semantic Web, RDF
- <http://www.w3.org/TR/rdf-primer/>
Linked Data
- <http://linkeddata.org/>
- <http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/>
Cool URIs for the Semantic Web
- <http://www.w3.org/TR/cooluris>
W3C Web Architecture
Representation 2
URI
Represents
Identifies
Resource
The tools we have to solve the
interoperability problem are:
• Resource
• URI
• Representation
Content Negotiation
Represents
Representation 1
Semantic Web
URI
Semantic
Web
Vocabularies
The tools we have to solve the
interoperability problem are:
• URI
• RDF
• Vocabularies
RDF
Linked Data
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Linked Data principles:
1. Use URIs as names for things.
2. Use HTTP URIs so that people can
look up those names.
3. When someone looks up a URI,
provide useful information.
4. Include links to other URIs. So that
they can discover more things.
OAI Object Reuse and Exchange: The Approach
Subject: Aggregations of Web resources
Approach: Instantiate Aggregations as Resources
with unique URIs on the Web
Approach: Publish Resource Maps to the Web that
Instantiate, Describe, and establish identity of
Aggregations
An Aggregation and the Web
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Resources of an
Aggregation are distinct
URI-identified Web
resources
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Missing are:
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The boundary that
delineates the
Aggregation in the Web
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An identity (URI) for the
Aggregation
Publish a Resource Map to the Web
The Resource Map Describes the Aggregation
The Resource Map and the Aggregation integrate into the Web
ORE Data Model
ORE Data Model
We want to have our cake and to eat it too (don't we all?):
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ORE should be simple and easy to use without deep
understanding
- Use simple tools and rules to create Atom Resource
Maps
ORE should have well crafted data model that enables
interoperability through well defined semantics
- Separate design from implementation
- Future-proof ORE – today's technologies will be
replaced (even HTTP?)
- Don't need to understand Data Model fully to do ORE
Aggregation: Resource that is a set of
resources
This resource is an Aggregated Resource
This resource is an Aggregation
A Relationship defined in the ORE vocabulary
Resource Map: Describes an Aggregation:
Resource
Map
Serialization
The resource has a representation
Implied as inverse of “describes”
HTTP GET
ore:isDescribedBy
This resource is a Resource Map
Recommend use if HTTP URIs
• HTTP is technology of today's web
• Want to be able to cite of refer to Aggregation but get Resource
Map describing it
o Follow Linked Data strategies to link: access URI-A, get
redirected to URI-R (HTTP 303) or simple # URI
o Provides notion of Authority
Multiple Resource Maps
o An Aggregation MAY be asserted and described by multiple
Resource Maps
o The purpose of multiple Resource Maps is to provide
descriptions of the Aggregation in multiple serializations (e.g.,
Atom, RDF/XML, RDFa, etc.)
o Each Resource Map MUST have only one representation
Authority
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Authoritative Resource Maps
o Get to Resource Map via Aggregation, usually created by
same authority
o Multiple: MUST be minimally equivalent (same Aggregated
Resources and Proxies), SHOULD assert mutual existence
Non-authoritative Resource Maps
o Best practice is to not create them
o Assert your own Aggregation instead
o Use rdfs:seeAlso to assert relationship between two
Aggregation
Multiple Resource Maps
RDF/XML
ore:describes
Atom
Atom
ore:describes
RDFa
These are non-authoritative Resource Maps
These are authoritative Resource Maps
Not much else
Association with another resource/identifier
Adding other properties to the core
The ReM
makes the
assertions
Required
Metadata
about the
ReM
Metadata
about the
Aggregation
Assertions about
Aggregated Resources.
Asserting other Relationships
The ReM makes
the assertions
Assertions about
the Aggregation.
Aggregation is a
journal
Aggregation has
another version “A”
“AR-3” is by Stephen
Hawking
Aggregated
Resources are
articles
Limits of Assertions thus Far
• The meaning of an RDF triple is independent of the context in
which it is stated
• Think of the difference:
o Carl is a man
o Carl is visiting Indianapolis
• All the triples described thus far are context independent
o Therefore they can have the URI of an aggregated
resource as subject or object
o But remember that is just the URI of the Resource and is
not exclusive of it being an Aggregated Resource
• Introduce proxy URI
Proxy: Stands for resource in context of other resource
hasNext might have meaning only in context
lineage: “this came from”
Reuse of data set AR-1 in Aggregation A-2.
ore:lineage predicate expressed origin or provenance of data.
Needs proxies because statement depends on contexts
ORE Deployment
arXiv.org: ORE possibilities
arXiv is an e-print archive of 500k scholarly articles
Express:
• Structure of arXiv: archives, sub-categories, articles
• Versioning: “article” (concept) and specific versions and
formats
• Articles by Joe Smith – somewhat like a result set
• Constituents of an article (metadata, PDF, source, video,
data, extracted references)
• Describe internal and external components (e.g. external
video associated with article but on Perimeter Institute
server)
• Use as part of workflow for ingest – assembly of
components, possible combination with SWORD
http://www.openarchives.org/oreChem/
SCOPE Architecture