Interoperability refers to the ability of devices or systems to participate in the coordinated execution of tasks and functions in some business process, in which data/information exchange happens in a transparent way, according to common protocols and formats. In fact, interoperability is achieved when the partners involved in the data/information exchange agree on the common information model and on the interfaces between their systems.
While interoperability can be achieved at the “syntactic” level, a full interoperability should be sought at “semantic” level, i.e. when interoperating systems are able to interpret the exchanged information automatically and meaningfully, so that exchanged messages are unambiguously defined and understood by the different parties.
The design of the Interoperability Framework (IF) element of the Shift2Rail Multi Annual Action Plan, and its initial implementation in the IT2Rail project, one of the “Shift2Rail lighthouse” projects, addresses these issues through the creation of an explicit, formal, shareable, machine-readable and computable description of the semantic reference model associated with data descriptions and exchanges; the ultimate goal is to allow for a higher degree of automation of distributed processes across multiple data formats and spanning unspecified actors.
These formal, explicit, machine-readable descriptions, in the form of domain ontologies, are maintained, stored and made accessible by the IF’s ontology repository and used to ‘annotate’ web services in the IF’s semantic web service repository.
Transforming and translating across different data formats requires an understanding of the domain concepts, facts or events that are represented by those formats. Whenever data items are associated with the machine-readable semantics provided by domain ontologies and mappings between them, this transformation can be automated through the use of computer-enabled semantic matching technologies.
Although more complex than data transformation, this is another instance of semantic matching, i.e. identifying compatible services or compositions of services based on logical statements, amenable to machine-processing, which describe the services capabilities, i.e. the services compatibility features, or the data transformations required to make them compatible. This is also already developed in part in IF component of the IT2Rail project, where semantic matching is used to identify services that can provide travel offers on end-to-end routes.
The ST4RT project proved the effectiveness of semantic-based data transformation by (a) defining a generic process to design, develop and deploy semantic “converters”, (b) developing a reference implementation of a semantic “converter” and customising this implementation in actual use cases for a specific pair of data formats involved in an exchange, e.g. in an after-sales transaction, and (c) deploying and evaluating the semantic-based data transformation. The demonstration use cases did not only involve data transformation, but also took into account the transactional nature of the considered exchange process, thus soliciting and exploiting both the semantic transformation at data level and at web service level.
The project experimented and evaluated the semantic interoperability approach described above. A global methodology was established, which could be applied to any scenario of semantic transformation. The designed methodology was then applied to a concrete cases of information exchange, by setting up proper tools for both the creation of the mappings and the actual transformation at the message level.
