A Web-Based Resource Model for eScience: Object Reuse & Exchange 2008 Microsoft eScience Conference Indianapolis, December 8, 2008

OAI-ORE Editors Carl Lagoze o Cornell University Herbert Van de Sompel o Los Alamos National Laboratory Pete Johnston o Eduserv Foundation Michael Nelson o Old Dominion University Rob Sanderson o University of Liverpool Simeon Warner o Cornell University

Joint work with …

OAI Object Reuse and Exchange: Support 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

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. textdata 1857 Astrophysics paper

Aggregations Those limitations seem to live on.

Aggregations Solving the problem with ad hoc methods. Photo plate kept separate from text (digitized version of original plate shown) text 1890 Astrophysics paper

Hubble optical observation Baltimore, MD Basic object information Strasbourg, France Aggregations Objects of interest in eScience are by nature compound. text 2006 Astrophysics paper X-MM-Newton X-ray observation Vilspa, Spain Chandra X-ray observation Cambridge, MA A1795

Aggregations! FormatsVersionsIdentifiersRelationshipsSplash page

Object Reuse and Exchange: A Web-Centric Approach 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 o Web Architecture - o Semantic Web, RDF - o Linked Data o Cool URIs for the Semantic Web -

W3C Web Architecture Resource URI Representation 2 Represents Representation 1 Represents Identifies Content Negotiation The tools we have to solve the interoperability problem are: Resource URI Representation

Semantic Web The tools we have to solve the interoperability problem are: URI RDF Vocabularies Semantic Web URIRDF Vocabularies

Linked Data 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: Publish Resource Maps to the Web that Instantiate, Describe, and establish identity of Aggregations Approach: Instantiate Aggregations as Resources with unique URIs on the Web

An Aggregation and the Web Resources of an Aggregation are distinct URI-identified Web resources Missing are: o The boundary that delineates the Aggregation in the Web o 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

We want to have our cake and to eat it too (don't we all?): o ORE should be simple and easy to use without deep understanding -Use simple tools and rules to create Atom Resource Maps o 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 Aggregation This resource is an Aggregated Resource A Relationship defined in the ORE vocabulary

Resource Map: Describes an Aggregation: This resource is a Resource Map Resource Map Serialization The resource has a representation HTTP GET ore:isDescribedBy Implied as inverse of describes

Based on Resource Description Framework (RDF) Resource #1 Resource #2 relatedTo Resource #3 relatedTo hasChapter follows SubjectPredicateObject R1hasChapterR2 R1hasChapterR3 followsR2 R1createdByCarl Lagoze Triples Carl Lagoze createdBy RDF model – multiple serializations: RFD/XML, Atom, RDFa

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 o 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 o 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 Atom RDFa Atom RDF/XML ore:describes These are authoritative Resource Maps These are non-authoritative Resource Maps

Not much else

Dont overload URI-A These resources mean something already. Dont use one URI for multiple information objects.

Association with another resource/identifier

Adding other properties to the core The ReM makes the assertions Metadata about the ReM Metadata about the Aggregation Required

Asserting other Relationships Aggregation is a journal Aggregation has another version A Aggregated Resources are articles AR-3 is by Stephen Hawking The ReM makes the assertions Assertions about the Aggregation. Assertions about Aggregated Resources.

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

SCOPE Architecture