The Concepts of WSMO - Enabling Semantic Web Services: The Web Service Modeling Ontology - page 69

Class stateSignature
hasNonFunctionalProperties type nonFunctionalProperties
importsOntology type ontology
usesMediator type ooMediator
hasStatic type mode
hasIn type mode
hasOut type mode
hasShared type mode
hasControlled type mode

Class mode sub − Class { concept, relation }
hasGrounding type grounding

The state for a given signature of a WSMO choreography is defined by all
legal WSMO identifiers, concepts, relations, and axioms. The elements that
can change and are used to express different states of a choreography, are
instances of concepts and relations, which are used similarly to locations in
ASMs. These changes are expressed in terms of the creation of new instances
or changes of attribute values.
In a similar way to the classification of locations and functions in ASMs,
the concepts and relations of an ontology are marked to support a particular
role (or mode). These roles are of five different types: static, in, out, shared,
and controlled.
Since Web services deal with actual instance data, the classification is
inherited by instances of the correspondingly classified concepts and relations.
That is, instances of controlled concepts and relations can only be created and
modified by the choreography interface; instances of “in” concepts can only be
read by the choreography interface; instances of “out” concepts can only be
created by the choreography interface, and cannot be read or modified after
their creation. Instances of shared concepts and relations can be read and
written by both the choreography interface and, possibly, the environment;
they can also be modified after creation. In the future, we expect shared
concepts to be particularly important for grounding alternatives to WSDL
which do not rely on strict message passing, such as semantically enabled
Tuple Spaces [39].

Trans i t i on Ru l e s

Unlike basic ASMs, the most basic forms of rules are not assignments, but
instead deal with basic operations on instance data, for example adding in-
stances to the signature ontology, removing instances, and updating instances.
To this end, we define atomic update functions to add, delete, and update in-
stances. This in turn allows us not only to add and remove instances to/from
concepts and relations, but also to add and remove attribute values for par-
ticular instances. In WSMO choreography, these basic updates are defined as
a set of fact modifiers, which are of four different types:

• add(fact);

• delete(fact);