Refactoring HUBzero for Linked

Data

Michael WittYongyang Yu

Purdue UniversityJCDL’12, Washington DC

Outline HUBzeroLinked DataData ModelingSoftware &ToolsConclusion

What is HUBzero?

• Web-based virtual research environment

• Publish and reuse resources (software, videos, datasets, etc.)

• LAMP stack (Linux, Apache, MySQL, PHP)

• Joomla! framework

HUBzero• Platform for scientific collaboration• Create and upload resources by

types• Courses, seminars, tools, downloads,

series, workshops, publications, and teaching materials

• Tag, rank, discuss, etc.

HUBzero Features• Interactive simulation tools – zoom in

on a graph, rotate a molecule, etc.• Online presentations – deliver online

presentation in flash format• Tool development areas – source

code management and version control

HUBzero Reference• http://hubzero.org• M.McLennan and R. Kennell,

HUBzero: a platform for dissemination and collaboration in computational science and engineering

What is Linked Data?

Linked Data

• URIs (names for various things)• HTTP URIs• Publish linked data in RDF format on

the Web• Links to other URIs

Data Modeling

Linked Data OAI-ORE Dublin Core Creative Commons

Object Reuse and Exchange (OAI-ORE)• Aggregation• Aggregated Resources (Nested

Aggregations)• Resource Maps

Dublin Core Mapping to HUBzero

Dublin Core HUBzero tabledc:title jos_resources.title

dc:creator jos_resources.created_bydc:subject jos_tags.raw_tag

dc:date jos_resources.createddc:identifier jos_resources.id

dc:description jos_resources.introtextdc:type jos_resources.type

dc:publisher (statically assigned)dc:rights jos_resources.params

Hub

downloads

Slimy salamander

Slimy.m4v

…

RM

RM

RM

<http://hub#agg> <ore:aggregates> <http://hub/downloads#agg>

Example: Modeling HUBzero with OAI-ORE

Implementation

• Resource component• Exposing metadata from MySQL RDB• Serialized in RDFa+XHTML

Aggregation

Resource Map

ore:aggregates

Software & Tools We Have Developed• Implementation of OAI-ORE for HUBzero• OAI-PMH Data Provider• RDF Crawler• Graph Browser

OAI-PMH Data Provider

• Implemented as a stand-alone component in Joomla

• Serialized as RDF/XML• Each resource type OAI-PMH set• OAI-ORE Resource Maps

ListMetadataFormats• ore:aggregates ListRecords

RDF Crawler

• A demonstration of utilizing linked data from the Web

• Starting from the top level of the hub• Parsing XHTML and dereferencing URIs• RDF triples to N-Triple file• N-Triple to Jena TDB triple store• Basis of the graph browser

Graph Browser

Graph Browser

HTTP URIs

string literalsshared boundaryof a larger graph

Graph Browser

Graph Browser

Summary

• Successfully extended and refactored HUBzero for Linked Data

• Exposed Hub resources with OAI-ORE, Dublin Core, Creative Commons, etc.

• Built software and tools to implement and utilize Linked Data from HUBzero

Future work• Incorporate richer and more specific

vocabularies e.g. Library of Congress Subject Headings (LCSH)• Enable users to create and publish their own

collections (Aggregations)• Enable semantic search

Acknowledgements

• National Leadership Grant(LG-05-10-0117-10) from

Institute of Museum and Libraries Services