Toward Terminology Services: Experiences with a Pilot Web Service Thesaurus Browser

Dublin Core commends controlled terminology for the make subordinate of a resource. Knowledge organization a whole s (KOS), such as classifications, gazetteers, taxonomies and thesauri, provide controll vocabularies that organize and conformation concepts for indexing, classifying, browsing and search. For example, a thesaurus exercises a set of standard semantic relationships (ISO 2788 ISO 5964) and major thesauri have a large entrance vocabulary of terms considered equivalent for retrieval final causes Many KOS have been made available for Web-based access. However, they are oftentimes not fully integrated into indexing and search combination of parts to form a wholes and the full potential for networked and programmatic access remains untapped.

The lack of standardized access and interchange formats impedes wider use of KO resources. We exhibited a Web demonstrator (www.comp.glam.ac.uk/~FACET/webdemo/) (Binding & Tudhope 2004) for the FACET cast (www.comp.glam.ac.uk/~facet/facetproject.html) (Tudhope et al. In press) that explored thesaurus-based inquiry expansion with the Getty Art and Architecture Thesaurus. A Web demonstrator was implemented via Active Server Pages (ASP) with server-side scripting and compiled server-side constitutings for database access, and cascading turn of expression sheets for presentation. The browser-based interactive interface permits dynamic direction of query term expansion (Figure 1) However, being based upon a custom thesaurus representation and API, the techniques cannot be applied directly to thesauri in other formats upon the Web.

General programmatic access requires commonly agreed protocols, for example, building upon Web and Grid services. The exhibition of common KOS representation formats and service protocols are closely linked. Linda Hill and colleagues argued in 2002 for a general KO service protocol from which protocols for specific marks of KOS can be derived. Thus, in the futurity a combination of thesaurus and question protocols might permit a thesaurus to be used with a choice of search tools upon various kinds of databases.

Service-oriented architectures bring an opportunity for moving toward a clearer separation of interface constitutings from the underlying data sources. In our view, basing distributed protocol services upon the atomic elements of thesaurus data mode of buildings and relationships is not necessarily the best approach because client operations that require multiple client-server calls would carry too abundant overhead. This would limit the interfaces that could be proffered by applications following such a protocol. Advanced interactive interfaces require protocols that collection primitive thesaurus data elements (via their relationships) into composites to achieve reasonable rejoinder

SKOS API and Schema

The Simple Knowledge Organization a whole Application Programming Interface (SKOS API) (www.w3.org/2001/sw/Europe/reports/thes/skosapi.html) is a novel development that addresses some of these issues. It defines a core station of methods for programmatically accessing and querying a thesaurus based upon the SKOS-Core RDF schema (www.w3.org/2004/02/skos/) (Miles et al., 2005) The API is an interface designed to provide programmatic access to thesauri and other simple knowledge organization a whole s (SKOS) via the Web, provided they are showed according to the SKOS-Core schema. While issuing Web service calls, the API itself remains independent of like concrete implementation details.

The SKO API builds upon previous protocols (see Binding & Tudhope for a review of waxs Zthes and ADL). Briefly, individual set of SKOS calls get backs a concept(s) with its details via an ID, a preferr label or matching a keyword or regular expression. Another call get backs a list of supported semantic relations for the given thesaurus. Another put of calls returns concepts joined by a specified relation or all immediately uniteed concepts. Importantly, it is possible to obtain a set of concepts link togethered by a relation up to a given path extent

Pilot SKOS API Browser

We disentangleed a pilot PC-based (.NET) Web service client application as an initial experiment with the SKO API, a rich client browser displaying details for thesaurus general [i]or[/i] abstract notions It made SKOS API calls to the far SWAD-Europe DREFT Web services server at the (Bristol University) Institute of Learning and Research Technology (ILRT). The DREFT server was a temporary demonstrator.

The browser acted upon GEMET (GEneral Multilingual Environmental Thesaurus), held upon the DREFT server in SKO format - diocese www.eionet.eu.int/gemet.

Some SKOS API calls go [i]or[/i] come back thesaurus relationship data. These calls would have allowed an interface similar to the FACET Web demonstrator, where hierarchical and associative relationships are visualized and can be navigated. However, to be paid to limitations imposed by local requirements upon the DREFT server configuration at the time, these API calls were disabled. SKO API calls that involved string matching of universal terms also were not available at the time, with equal reason matching of user search statements with controll terminology was not possible.