OWL-S-Semantic-Markup-for-Web-Services #

With OWL-S markup of services, the information necessary for Web service discovery could be specified as computer-interpretable semantic markup at the service Web sites, and a service registry or ontology-enhanced search engine could be used to locate the services automatically. For nontrivial services (those composed of several steps over time), this description may be used by a service-seeking agent in at least four different ways: (1) to perform a more in-depth analysis of whether the service meets its needs; (2) to compose service descriptions from multiple services to perform a specific task; (3) during the course of the service enactment, to coordinate the activities of the different participants; and (4) to monitor the execution of the service. Specifically, it specifies the inputs required by the service and the outputs generated; furthermore, since a service may require external conditions to be satisfied, and it has the effect of changing such conditions, the profile describes the preconditions required by the service and the expected effects that result from the execution of the service.

4.1 Compiling a Profile: The Relation with Process Model #

The Profile of a service provides a concise description of the service to a registry, but once the service has been selected the Profile is useless; rather, the client will use the Process Model to control the interaction with the service.

4.2 Profile Properties #

In the following we describe in detail the main parts of the profile model; we classify them into four sections: the first one (4.2.1) describes the properties that link the Service Profile class with the Service class and Process Model class; the second section (4.2.2) describes the form of contact information and the Description of the profile – this is information usually intended for human consumption; in the third section (4.2.3), we discuss the functional representation in terms of IOPEs; finally, in the last section (4.2.4), we describe the attributes of the Profile. Specifically, OWL-S 1.1 defines a subclass of ServiceModel, Process, which draws upon well-established work in a variety of fields, including work in AI on standardizations of planning languages [6], work in programming languages and distributed systems [20,19], emerging standards in process modeling and workflow technology such as the NIST’s Process Specification Language (PSL) [22] and the Workflow Management Coalition effort (http://www.aiim.org/wfmc), work on modeling verb semantics and event structure [21], previous work on action-inspired Web service markup [18], work in AI on modeling complex actions [13], and work in agent communication languages [15,5]. OWL-S%20Semantic%20Markup%20for%20Web%20Services%20bd3854383c384f6bbadb130c2a33d256/Process-Model-1.1.gif #

Top level of the process ontology Atomic processes correspond to the actions a service can perform by engaging it in a single interaction; composite processes correspond to actions that require multi-step protocols and/or multiple server actions; finally, simple processes provide an abstraction mechanism to provide multiple views of the same process.