A language specification approach to semantic interoperability

Arne-Jxrgen Berre, David Skogan
SINTEF Telecom and Informatics P.O.Box 124, Blindern, N-0314 Oslo, Norway
{ Arne.J.Berre | David.Skogan }@informatics.sintef.no
http://www.informatics.sintef.no

Position statement abstract

The position being argued for is that the work on interoperating geographic information systems should be based on the general IT work in the areas of syste ms integration, schema integration, semantic interoperability and multidatabase systems. In particular for the important area of semantic interoperability we ad vocate for a possibility to support a language specification approach, based on concepts from schema integration mapping languages such as EXPRESS-X, in additio n to a dictionary approach for semantic translators. Further research is require d in this area in order to apply and specialize these concepts to the GIS domain.

1. Semantic Interoperability Problems and Solutions

The problem of structural and semantic interoperability between data from di fferent information communities, is similar to the problem of schema integration in multidatabases.

There is a set of well known structural conflicts that might arise [KS91], - such as synonyms, homonyms, data representation conflicts, data unit conflicts, data precision conflicts, data quality conflicts, default value conflicts and i ntegrity constraint conflicts.

In addition to try to map equivalent objects on a one-to-one syntactical bas is, one can define a semantic measure for equivalence of objects. A taxonomy tar geted on defining semantic proximity has been developed by [SK92] and mapped to object-oriented models in [EK95]. Semantic proximity is defined as a function be tween 0 and 1, based on context, abstraction, domain and state of the objects. T he taxonomy distinguishes between semantic incompatibility, semantic resemblance , semantic relevance, semantic relationship and semantic equivalence.

2. EXPRESS-X and mapping languages

Examples of approaches that addresses structural and semantic interoperabil ity can be found both in database mapping languages, and in conceptual schema mo deling languages such as EXPRESS.

EXPRESS-X [EX97] is currently in the ISO standard development, based on a un ificiation of two previous mapping languages, EXPRESS-M [EM95] and EXPRESS-V.

A description of ODL-M for the object-oriented databases standard from ODMG is described in [KI96]. The problem of semantic interoperability is being addre ssed through support for a semantic proximity function.

3. Application of mapping languages to GIS

The use of a mapping language is in particular feasible when a conceptual sc hema language has been used in the specification of a generic feature model and corresponding application schemas. Both the ISO/TC21 and CEN/TC287 standards a dvocates such an approach, while the OGC/OpenGIS standard is only working throug h a dynamic API.

4. Conclusions and future work

In this position statement we argue for further addressing research in the a rea of semantic interoperability, in particular through extending work on mappin g languages for schema integration, from the area of multidatabase systems.

5. References

[EX97] "EXPRESS-X", Mapping language based on EXPRESS-M and EXPRESS-V in progr ess in the ISO STEP/EXPRESS community

[EM95] "EXPRESS-M Reference Manual", CIMIO Ltd, August 1995

[KI96] "ODL-M - A Mapping Language for Schema Integration in Object-Oriented Mu ltidatabase Systems" MSC-thesis, Steinar Kindingstad, University of Oslo/SINTEF, August 1996

[KO95] "Semantic Proximity in Multidatabases", MSC-thesis, Espen Koren, University of Oslo/SINTEF, July 1995

[SK93] "Multimodels for GIS", MSC-thesis, David Skogan, University of Trondheim, December 1993

[BE93] "An Object-Oriented Framework for Systems Integration and Interoperability", A.J. Berre, Phd-thesis, University of Trondheim, August 1993

[SK92] "So far (Schematically) yet so near (Semantically)", Amit Sheth, V. Kash yap, IFIP DS-5, Semantics of Interoperable Database Systems, Australia, November 1992

[KS91] "Classifying Schematic and Data Heterogeneity in Multidatabase Systems", Won Kim, Jungyen Seo, IEEE Computer,   (22)3, December 1991