RDF(S), tools

• We have a solid specification since 2004: well defined (formal) semantics, clear RDF/XML syntax
• Lots of tools are available. Are listed on W3C’s wiki:
  • RDF programming environment for 14+ languages, including C, C++, Python, Java, Javascript, Ruby, PHP,… (no Cobol or Ada yet )
  • 13+ Triple Stores, ie, database systems to store datasets
  • 16+ general development tools (specialized editors, application builders, …)
  • etc

RDF(S), tools (cont.)

• Note the large number of large corporations among the tool developers: Adobe, IBM, Software AG, Oracle, HP, Northrop Grumman, …
• …but the small companies and independent developers also play a major role!
• Some of the tools are Open Source, some are not; some are very mature, some are not : it is the usual picture of software tools, nothing special any more!
• Anybody can start developing RDF-based applications today

RDF(S), tools (cont.)

• There are lots of tutorials, overviews, or books around
  • the wiki page on books lists 20+ (English) textbooks; 19+ proceedings for 2005 & 2006 alone…
  • again, some of them good, some of them bad, just as with any other areas…
• Active developers’ communities

Large datasets are accumulating

• IngentaConnect bibliographic metadata storage: over 200 million triplets
• UniProt Protein Database: 262 million triplets
• RDF version of Wikipedia: more than 47 million triplets
• RDFS/OWL Representation of Wordnet: 150MB of RDF/XML
  • a good example on how to organize large amount of RDF data
• “Département/canton/commune” structure of France published by the French Statistical Institute
• This conference has reported on more!

Ontologies: OWL

• This is also a stable specification since 2004
• Looking at the tool list on W3C’s wiki again:
  • a number programming environments (in Java, Prolog, …) include OWL reasoners (OWL-Lite or OWL-DL)
  • there are also stand-alone reasoners (downloadable or on the Web)
  • ontology editors come to the fore

Ontologies

• Large ontologies are being developed (converted from other formats or defined in OWL)
  • eClassOwl: eBusiness ontology for products and services, 75,000 classes and 5,500 properties
  • the Gene Ontology: to describe gene and gene product attributes in any organism
  • UniProt: protein sequence and annotation terminology and data
  • again, look around at the conference… 

Vocabularies

• There are also a number “core vocabularies” (not necessarily OWL based)
  • SKOS Core: about knowledge systems
    • still to be finalized at W3C
  • Dublin Core: about information resources, digital libraries, with extensions for rights, permissions, digital right management
  • FOAF: about people and their organizations
  • DOAP: on the descriptions of software projects
  • MusicBrainz: on the description of CDs, music tracks, …
  • SIOC: Semantically-Interlinked Online Communities
  • …
• More are needed; active community participation is important!

Ontologies, vocabularies

• Ontology and vocabulary development is still a complex task, we all know that…
• The W3C SW Best Practices and Deployment Working Group has developed some documents:
  • “Best Practice Recipes for Publishing RDF Vocabularies”
  • “Defining N-ary relations”
  • “Representing Classes As Property Values”
  • “Representing "value partitions" and "value sets"”
  • “XML Schema Datatypes in RDF and OWL”
  The work is continuing in the (new) SW Deployment Working Group, watch this space (and contribute if you can…)!

Querying RDF: SPARQL

• SPARQL has stirred lots of interest already (though not yet finished)
• It is an essential piece of the Semantic Web puzzle
• There already a 20+ implementations already(!), either stand alone or part of a system
• A number of SPARQL “endpoints” make it possible to experiment with it already!

Some words of warning on SPARQL…

• It is not a Recommendation yet
• New issues came up (at the CR phase)
  • need for a very precise semantics and that is not easy 
  • these issues forced the Working Group to go “back” to a Working Draft from Candidate Recommendation
  • but they should sort his out in 2007
• Some features are not included
  • control and/or description on the entailment regimes of the triple store (RDFS? OWL-DL? OWL-Lite? …)
  • modify the triple store
  • …
  postponed to a next version…

Of course, not everything is so rosy…

• There are a number of issues, problems, “to-do”-s
  • how to get RDF data
  • missing functionalities: rules, “light” ontologies, fuzzy reasoning, necessity to review RDF and OWL, …
  • misconceptions, messaging problems
  • need for more applications, deployment, acceptance
  • maping relational databases to RDF
  • get your data out there!
  • etc

How to get RDF data?

• Of course, one could create RDF data manually…
• … but that is unrealistic on a large scale
• Goal is to generate RDF data automatically when possible and “fill in” by hand only when necessary

Data may be around already…

• “SW-aware” tools are around, though more would be good:
  • Photoshop CS stores metadata in RDF in, say, jpg files (using XMP)
  • RSS 1.0 feeds are generated by (almost) all blogging systems
  • various works on semantic wikis
  • etc…

Data may be extracted (a.k.a. “scraped”)

• Different tools, services, etc, come around every day:
  • get RDF data associated with images, for example:
    • service to get RDF from flickr images (see example)
    • service to get RDF from XMP (see example)
  • XSLT scripts to retrieve microformat data from XHTML files
  • scripts to convert spreadsheets to RDF
  • etc
• Most of these tools are still individual “hacks”, but show a general tendency
• Hopefully more tools will emerge

RDF from XML/XHTML: GRDDL

• GRDDL is a more systematic way of accessing data and turn it into RDF:
  • defines XML attributes to bind a suitable (usually XSLT) script to transform (part of) the data into RDF (also has a variant for XHTML)
    • a “GRDDL Processor” would then run the script and produce RDF on–the–fly
  • is a possible link to microformats
  • developed in a dedicated W3C Working Group, should be finished in 2007
    • aims at setting a record as the W3C Working Group with the shortest life-span 

RDF from XML/XHTML: RDFa

• RDFa (formerly RDF/A) extends XHTML by:
  • extending the link and meta to include child elements
  • add metadata to any elements (a bit like the class in microformats, but via dedicated properties)
  • easier mix of terminologies via namespaces
  • a general framework, ie, no extra scripting is necessary, only one general RDFa tool
  • aims at a complete representation (“serialization”) of RDF embedded in XHTML
    • not bound to XHTML2 (any more); goal is to have an XHTML1 module
  • developed in the SW Deployment Working Group

GRDDL & RDFa example

See my public page (marked up both with RDFa and microformats)

SPARQL-ing such data

• http://www.sparql.org/sparql?query=…
  with the query:

SELECT DISTINCT ?name ?home ?orgRole ?orgName ?orgHome
# RDFa-ing my home page:
FROM <http://torrez.us/services/rdfa/http://www.w3.org/People/Ivan/>
# GRDDL-ing http://www.w3.org/Member/Mail:
FROM <…online_xslt/xslt?…rdf-in-xhtml-processor&xmlfile=…%2FMember%2FMail%2F…>
WHERE {
    ?foafPerson foaf:mbox ?mail; 
        foaf:homepage ?home.
    ?individual contact:mailbox ?mail; 
        contact:fullName ?name.
    ?orgUnit ?orgRole ?individual; 
         org:name ?orgName; 
         contact:homePage ?orgHome.
}

• yields…

SPARQL as a unifying point?

Missing pieces of the SW puzzle…

• Everybody has a favorite item, ie, the list tends to infinite…
• W3C is a standardization body, and has to look at where a consensus can be found

Rules

• OWL-DL and OWL-Lite are based on Description Logic; there are things that DL cannot express
  • a well known examples is Horn rules (eg, the “uncle” relationship):
    • (P₁ ∧ P₂ ∧ …) → C
    • e.g.: for any «X», «Y» and «Z»: “if «Y» is a parent of «X», and «Z» is a brother of «Y» then «Z» is the uncle of «X»”
  • there are a number of attempts to combined these: RuleML, SWRL, cwm, …
• There is also an increasing number of rule-based system that want to interchange rules
  • a new type of data (potentially) on the Web to be interchanged…

Some typical use cases

• Negotiate eBusiness contracts across platforms: supply vendor-neutral representation of your business rules so that others may find you
• Describe privacy requirements and policies, and let clients “merge” those (e.g., when paying with a credit card)
• Medical decision support, combining rules on diagnoses, drug prescription conditions, etc,
• Extend RDFS (or OWL) with rule-based statements (e.g., the uncle example)

In an ideal World…

• One would define a full Rule Interchange Format, that all rule systems could translate to and from
• That format could also be used to implement rules for (e.g.) RDF data and OWL ontologies

In the real World…

• Rule based systems can be very different
  • different rule semantics (based on various type of model theories, on proof systems, etc)
  • production rule systems, with procedural references, state transitions, etc

In the real World…

• The Rules Interchange Format WG defines a “core” that is common to all…
  • a “minimal” but useful level that covers a large percentage of use cases (probably “full Horn”) with clear semantics
  • this core will be usable with RDF data, OWL ontologies…
    • details are still to be worked out, a first document might be out before the end of the year…
• … then categorizes the various systems and shows how the core should be extended to cover the various functionalities
• I.e., we will have a set of “variants” to cover various needs
• Hopefully the first results in 2007 (publication of the “core”)

Issues floating around for RDF(S), OWL…

• Extensions/changes of the RDF(S) core
  • “named graphs”, probabilistic and/or fuzzy statements, timed statements, …
  • remove some restrictions (bNodes as predicates, literals as subject, …)
  • should we keep the containers?
  • internationalization issues with literals (how do I set “bidi” writing?)
• OWL 1.1
  • “qualified cardinality restrictions” (i.e., “class instance must have two black cats”)
  • disjoint properties
  • reflexive, irreflexive properties
  • own datatype construct instead of complex XML Schema datatypes
  • some syntactic sugar (eg, disjoint union)
  • …
• Alternative serializations (eg, giving Turtle a final form)
• API standardization (eg, having a stable RDF API in Javascript for Web Applications)
• Access control, signatures, provenance

All on the “radar screen” of W3C…

A major problem: messaging

• Some of the messaging on Semantic Web has gone terribly wrong . See these statements:
  • “the Semantic Web is a reincarnation of Artificial Intelligence on the Web”
  • “it relies on giant, centrally controlled ontologies for "meaning" (as opposed to a democratic, bottom–up control of terms)”
  • “one has to add metadata to all Web pages, convert all relational databases, and XML data to use the Semantic Web”
  • “it is just an ugly application of XML”
  • “one has to learn formal logic, knowledge representation techniques, description logic, etc, to use it”
  • “it is, essentially, an academic project, of no interest for industry”
  • …
• Some simple messages should come to the fore!

Improve messaging: SWEO

• A new “Semantic Web Education and Outreach” Interest Group has just been started
• Goals are:
  • collect and document real SW use cases, make the available to the World
  • improve the general messaging via guidelines to tutorial, teaching materials, FAQ-s
• First face-to-face meeting will be next week…

Semantic Web adoption

• SW has indeed a strong foundation in research results
• But remember:
  • (1) the Web was born at CERN…
  • (2) …was first picked up by high energy physicists…
  • (3) …then by academia at large…
  • (4) …then by small businesses and start-ups…
  • (5) “big business” came only later!
• network effect kicked in early…
• Semantic Web is now at #4, and moving to #5!

The “corporate” landscape is moving

• Remember the companies’ presence in tools?
• Some of the active participants in W3C SW related groups: ILOG, HP, Agfa, SRI International, Fair Isaac Corp., Oracle, Boeing, IBM, Chevron, Siemens, Nokia, Merck, Pfizer, AstraZeneca, Sun, Citigroup, …
• “Corporate Semantic Web” listed as major technology by Gartner in 2006
• The Semantic Technology Conference series also attract lots of participants
  • speakers in 2006: from IBM, Cisco, BellSouth, GE, Walt Disney, Nokia, Oracle, …
  • not all referring to Semantic Web (eg, RDF, OWL, …) but semantics in general, but they might come around!

Adoption may start with special communities

• The needs of a deployment application area:
  • have serious problem or opportunity
  • have the intellectual interest to pick up new things
  • have motivation to fix the problem
  • its data connects to other application areas
  • have an influence as a showcase for others
• The high energy physics community played this role for the Web in the 90’s

Some RDF deployment areas (cont)

• Some deployment areas are already very active: health care and life sciences, digital libraries, defense
  • also at W3C, in the form of an Interest Group for HCLS (participants include Oracle, IBM, Merck, Pfizer, AstraZeneca, …)
  • look at their workshop proceedings of this week…
• Others are coming to the fore: eGovernment, energy sector (eg, oil industry), financial services, legal profession, …

Some typical adoption problems

• Change of concepts, habits, traditions
  • adoption of URI-s for one’s data
  • accept (and appreciate!) sharing and reusing (eg, ontologies)
  • privacy, access control, provencance issues
    • applications may be restricted to Intranets today; this is not unlike the early Web applications…
• Access to legacy data (eg, in databases), how to do that, etc
• Efficiency of the tools (eg, triple stores), need for other class of tools (visual representation of data, connection to relational databases, etc)
• Understanding the technology and its advantages (back to the messaging problem…)

Applications are not always very complex…

• Eg: simple semantic annotations of patients’ data greatly enhances communications among doctors
• What is needed: some simple ontologies, an RDFa/microformat type editing environment
• Simple but powerful!

A major adoption area: data integration

• Data integration comes to the fore as one of the SW Application areas
• Very important for large application areas (life sciences, energy sector, eGovernment, financial institutions), as well as everyday applications (eg, reconciliation of calendar data)
• Life sciences example:
  • data in different labs…
  • data aimed at scientists, managers, clinical trial participants…
  • large scale public ontologies (genes, proteins, antibodies, …)
  • different formats (databases, spreadsheets, XML data, XHTML pages)
  • etc

There has been lots of R&D in the area

• Boeing, MITRE Corp., Elsevier, EU Projects like Sculpteur and Artiste, national projects like MuseoSuomi, DartGrid, …
• Developments are under way at various places in the area
• Issue: is your RDF data visible?

Not only data integration: eg, portals

• Vodafone's Live Mobile Portal
  • search application (e.g. ringtone, game, picture) using RDF
    • page views per download decreased 50%
    • ringtone up 20% in 2 months
• A number of other portal examples: Sun’s White Paper Collections and System Handbook collections; Nokia’s S60 support portal; Harper’s Online magazine linking items via an internal ontology; Oracle’s virtual press room; Opera’s community site, Yahoo! Food…
• Issue (again): is your RDF data visible?

Improved search via ontology: GoPubMed

• Improved search on top of pubmed.org
  • search results are ranked using the specialized ontologies
  • extra search terms are generated and terms are highlighted
• Importance of domain specific ontologies for search improvement

Conclusions

• We have gone a long way (thanks to all of you!)
• We live exciting times in terms of SW Adoption
• Of course lots of work is still to be done (life would be boring otherwise…)

Thank you for your attention!

These slides are publicly available on:

http://www.w3.org/2006/Talks/1109-Athens-IH/

in XHTML and PDF formats; the XHTML version has active links that you can follow