Linked Data Virtualization

Linked Data Driven Data Virtualization


for Web-scale Integration

Situation Analysis

• Agility via ad hoc data access has prevailed throughout the history of IT.
• Data, heterogeneity are growing exponentially, across Intranets, Extranets, and the Internet
• Processing windows remain static (we still only have 24 hrs. in a day for personal and professional activities)
• Individual and Enterprise Agility remains totally dependent on data access, manipulation, and dissemination
• Data remains dirty and its context remains necessary for extracting meaning.
• Data Virtualization (in the form of heterogeneous Linked Data Spaces) remains the only viable way forward.

What is Linked Data?

• RDF (Resource Description Framework) Data Model - a graph model where records take the form of 3-tuples i.e., subject-predicate-object or entity-attribute-value
• RDF Data Serialization Formats - (X)HTML+RDFa, Turtle, N3, TriX, RDF/XML, and others
• RDF Data Item Identity - is HTTP URI based
• RDF is inherently schema-last and self-describing
• Linked Data - application of RDF model where records identifiers, fields, and optionally field values, are endowed with HTTP scheme URIs whether instance data (ABox) or data dictionary data (TBox)
• Linked Data enables follow-your-nose traversal of RDF data records where every record identifier, field, or field value is a data pathway

The Linked Data Landscape

• Core vocabularies - common terms facilitate integration:
  • FOAF for Personal Profile
  • SIOC for Social Networking
  • Dublin Core for Bibliography
  • GoodRelations for eCommerce
  • Geonames
• Domain specific vocabularies for all verticals:
  • OBO Foundry for biology
• Dbpedia, OpenCYC, Yago, SUMO, Geonames etc. define URIs for talking about almost any well known real world entity or class of entities.

The Linked Open Data Cloud

What Linked Data Offers for Data Integration

• In RDF, all things have a single-part global HTTP based Identifier: Anything can join with anything else through its URI.Many people will use a different identifier for the same thing.
• Whether two things can be considered the same depends on context. OWL sameAs is a generic way of stating identity co-reference.Literal values can be tagged by type or language, allowing explicit representation of units of measure etc.RDF Triples are contained in Named Graphs. The graph usually denotes provenance, and it has a URI, about which further statements can be made

RDF vs. Relational

• When the data is ragged and highly heterogenous, with schema last needs, use RDF and Linked Data
• The more different sources of data, the more you will need RDF and Linked Data
• If data is highly regular and uniform, relational offers higher performance: Application specific indices are faster than putting everything in a generic index scheme

Incentives for Publishing

• If one is on the web, one is there in order to be found
• Publishing data in standard vocabularies allows applications to mesh data from many Web-addressable Data Spaces (e.g. Pages)
• In the end, Linked Data will enhance the end user experience by added serendipitous discovery and increased relevance

Models for Publishing

• Linked data is usually published in large dumps which have a release cycle
• Any relational database's contents can be published as linked data through generating RDF on demand via a relational to RDF schema mapping
• Whether one generates RDF on demand or ETLs RDBs as RDF depends on use case

Use Case: CRM and MIS

• At OpenLink internal IT, all CRM, Support, Blogs, Wikis available as linked data
• Interactive drill down from products to support tickets to customers to docs, etc.
• Currently working on projects about exposing enterprise CRM as linked data

Use Case: The Neurocommons

Bio2RDF - some of the larger datasets

Use Case: BBC Programs and Music Service

• Data Harvested via Sitemap and Web Crawling 20M Triples
• Integrated to Last.FM, Dbpedia, Musicbrainz: See what any of these has to say about an artist of work.
• http://bbc.openlinksw.com

Use Case: Linked Open Data Cloud Service

• Dbpedia, Freebase, Geodata, Neurocommons, Bio2RDF, Govtrack, US Census, RKB Explorer
• Pingthesemanticweb, Good Relations and more
• Entity Ranks
• Full Text, SPARQL, Faceted Browsing
• http://lod2.openlinksw.com
• http://lod.openlinksw.com
• 7.59 billion triples

The Generations of the Web

• Web 1.0 - Publishing for all
• Web 2.0 - User generated content, mashups, the citizen journalist
• Linked Data Web - Big data, integration and analytics for all.