Information visualisation workshop

Conceptual open hypermedia: informed WWW link navigation using ontologies (Carole Goble, University of Manchester)

The aim of this project is to research into methods to improve significantly the quality, consistency and breadth of linking of WWW documents at retrieval time (as readers browse the documents) and authoring time (as authors create the documents). The objective is link creation rather than resource discovery.

The project plans to produce a COHSE (Conceptual Open Hypermedia Services Environment) using three leading-edge technologies:

1. an ontological reasoning service which is used to represent a sophisticated conceptual model of document terms and their relationships;

2. a Web-based open hypermedia link service that can offer a range of different link-providing facilities in a scalable and non-intrusive fashion;

3. the integration of the ontology service and the open hypermedia link service to form a conceptual hypermedia system to enable documents to be linked via metadata describing their contents.

A first phase pilot has already been developed and demonstrated with a museum collection application. COHSE is a system powered by OIL (Ontology Inference Layer).

e-mail: [e-mail]
URL: http://img.cs.man.ac.uk/carole, http://inanna.ecs.soton.ac.uk/cohse
Other contacts: Sean Bechhofer ([e-mail]), Les Carr, Steve Harris, Dave de Roure, Wendy Hall (@ecs.soton.ac.uk)

Enabling technologies for semantic interoperability (Jérôme Euzenat, INRIA Rhône-Alpes)

The vision of a "semantic web" is realised by the annotation of each web page, containing informal knowledge as we know it now, with formal knowledge whose terminology is described in an ontology. For several reasons (legacy knowledge, ease of use, heterogeneity of devices and adaptability, timelessness), it is not likely that this formal knowledge will be encoded in the very same language. The interoperability of the formal knowledge languages must then be studied in order to gather, to transform and to adapt the knowledge acquired through the semantic web.

We are pursuing researches for achieving interoperability between these formal annotations at the semantic level (i.e. based on the meaning of the knowledge language constructs). Several complementary tracks of research are developing: describing modular families of languages allows to deal with adaptability by choosing the most suitable language while easing the exchange of knowledge; the pattern approach (followed with Heiner Stuckenschmidt) allows to describe structures shared by languages from which it is easier to transform knowledge; the transformation and property approach allows to define the properties satisfied by elementary transformations (e.g. meaning preservation) and the combination of such transformations preserving properties.

These tracks share common grounds such as the description of the semantics of the used languages and proof checking techniques that can be part of the web of trust.

e-mail: [e-mail]
URL: http://www.inrialpes.fr/exmo

Objectifying the Web the "light" way: an RDF-based framework for the description of Web objects and services (Pasqualino Assini, The Data Archive - University of Essex)

Although the advantages of object-oriented (OO) programming are well-known none among the main distributed OO middlewares (DCOM,CORBA and Java RMI) has been widely adopted for the developing of Internet applications. Developers seems to perceive these approaches as over-complex (COM and CORBA), proprietary (COM and RMI), and incompatible with current WWW development practices. Recognizing these difficulties more WWW-friendly proposals are starting to appear (e.g., XML-RPC , SOAP). The paper describes a 'light' approach to objectifying the WWW that provides most of the advantages of object-orientation while mantaining full compatibility with the existing WWW infrastructure and requiring only modest changes to existing applications to allow them to partecipate to the Object Web.

e-mail: [e-mail]
URL: http://www.data-archive.ac.uk

Querying RDF using an SQL-ish query language (Libby Miller, ILRT, University of Bristol)

The major query APIs in Java for RDF have been graph navigation APIs, which work at a very low level, for example Sergay Melnik's RDF API and Brain McBride's Jen API. A typical query would be

Model find (Resource, Property, Resource); where any argument can be null.

Navigating RDF graphs at this level of detail is necessary for the specialist RDF application developer, but for the mainstream web developer low level queries like this are offputting, and as it turns out, unnecessary. It is important to simplify the access to RDF data stores, so that simple and ontology-enabled RDF data stores can be exposed to mainstream developers. We have developed a prototype query langauge which can do this.

A great deal of work has been done on semi-structured query languages: the work here draws on R. V. Guha's RDFDB QL and also the Algae work by Eric Prud'hommeaux, the QL described in the recent paper by Karvounarakis, Christophides, Plexousakis and Alexaki on RQL, as well as those described in 'Data on the Web' by Abiteboul, Buneman and Suciu.

We have taken the JDBC API and RSS as canonically mainstream technologies that can be usefully co-opted by RDF. We have built a demonstration query system over the top of the Java Jena and Melnik APIs which uses an SQL-like query language to query in-memory or on-disk (Postgres) RDF data stores.

We used a cut-down JDBC API to query the RDF data stores. This means that there is a familiar interface for Java developers to the RDF data store, which returns a ResultSet object. It also means that we can write simple jsp pages to query RDF databases and display the results.

One application of this is to the new RSS 1.0 channel data. RSS 1.0 is an RDF format. Its usual application is for providing a summary view of information from a site, which can then be displayed by a viewer or aggregator. Since it is implemented in RDF, however, we can also aggregate the data and query it using the SQL-like query language. For example, if the RSS data includes information about job adverts, we could have a query:

SELECT ?z, ?a FROM http://ilrt.org/discovery/2000/11/rss-query/jobs-rss.rdf, http://ilrt.org/discovery/2000/11/rss-query/jobs.rss WHERE ({job::advertises} ?x ?y) ({job::salary} ?y ?z) ({job::title} ?y ?a) AND ?z > 55000 USING job FOR http://ilrt.org/discovery/2000/11/rss-query/jobvocab.rdf#

producing a result set

?y ?z web developer 60000 perl programmer 56000

Result: simple or complex RDF data becomes accessible to mainstream Java server-side developers.

Thanks to Dan Brickley for much useful input.

More detail is at http://ilrt.org/discovery/2000/10/swsql

related work: http://ilrt.org/discovery/2000/11/rss-query

demo/download: http://swordfish.rdfweb.org/rdfquery

RQL: http://www.ics.forth.gr/proj/isst/RDF/RQL/rql.html

Algae: http://www.w3.org/1999/02/26-modules/User/Algae-HOWTO.html

Guha's RDFDB http://web1.guha.com/rdfdb

e-mail: [e-mail]
URL: http://www.ilrt.bris.ac.uk , http://www.ilrt.bris.ac.uk/discovery