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This deliverable exemplifies the usage of the Web Service Modeling Ontology WSMO for modeling Semantic Web Services along with specific technological solutions. This document defines the general organization of WSMO use cases, and presents specific examples of WSMO use cases.
WSMO Standard: D2 v1.0 Web Service Modeling Ontology (WSMO)
WSMO Primer: D3.1 v0.1 WSMO Primer
WSMO Reasoning: D5.1 v0.1 WSMO Discovery
WSMO Use Case: D3.3 v0.1 Virtual Travel Agency
WSMO Use Case: D3.4 v0.1 B2B - Business Document Exchange
WSMO Use Case: D3.5 v0.1 SWF Use Case
This Deliverable presents several use cases which exemplify WSMO usage for specific real-life purposes. The different use cases presented in this document provide valuable insight for testing and adapting the modeling constructs provided in WSMO in real-world scenarios for Web Services. So, besides demonstrating how to model Web Services in WSMO, the use cases also allow us to demonstrate the adequacy of our approach in terms of providing an exhaustive framework for covering all relevant aspects of semantic description of Web Services. Over time, additional use cases will be added in order to expand the range of possible solutions for Semantic Web Service technologies using WSMO.
This document is organized as follows: Section 2 defines the general organization of WSMO Use Cases; Section 3 presents examples of specific WSMO use cases. Section 4 concludes the document. A Change Tracker in the Appendix explicitly identifies the major changes made from earlier versions of this document to the latest version, in order to facilitate readers following the improvements.
A WSMO use case description document is organised into four subsections, as follows: First, there is a general description of the use case setting and the technical aspects to be addressed. This is followed by a tabluar overview of the WSMO resources modeled in the use case. Next the resources' models in WSML are outlined, and finally, the technical solutions developed or addressed within a use case are presented.
More detailed explanations of the four subsections of the general structureare given below.
The aim of this subsection is to provide a description of the use case from a real world perspective, without regard to technical realization. Therefore, we slightly modify the methodology of the W3C Web Services Architecture Working Group for use case descriptions and extend it by the requirements arising for Semantic Web Services technologies (see [He et al., 2004]). The aspects considered for this general description are defined as follows:
- participating actors and their goals
- activities to be performed
- technological requirements
- possible extensions of the scenario.
In order to allow readers to gain a reasonable understanding of the WSMO resources defined in a use case as well as their relationships and interplay, a tabular overview of all resources defined in the use case is provided. For each component, a table is provided that describes the component. Table 1 is an example for such a component description, taken from the VTA use case (see Section 3.1); the VTA use case document also contains 'templates' for the tabluar descriptions of the other WSMO components.
| WSMO component type | ontology |
| name | International Train Ticket Ontology |
| description | defines ontology constructs for the domain of international train connections |
| imported ontologies / used mediators |
- Date and Time Ontology - Location Ontology - OWL Person Mediator - OWL Fact Book Mediator |
| main contructs | main concepts: station, itinerary, trip, traintrip axioms: stationCountry, departureBeforeArrival, startNotEqualEnd instances: innsbruckHbf , frankfurtHbf |
| WSML model | number / link to the listing with the WSML model of the resource |
The third subsection of a WSMO use case description document provides the WSML models for the resources, along with detailed explanations about modeling decisions or other explanations relating to specific resources.
The WSML models are presented in numbered Listings. For technical realization within a HTML document, the following assisting accessories are provided and recommended for use:
<table class="listing" width="100%" border="1">
<caption>Listing 1. Domain Ontology International Train
Ticket</caption>
<tbody><tr>
<td class="listing"><!--#include file="resources/tc.wsml.html"
--><br />
</td></tr>
</tbody>
</table>
Detailed explanations will help the reader to understand the design and definition of a specific component. Such explanations are optional, but recommended, because they can be very helpful for readers not familiar with the WSML syntax or WSMO. For example, for ontologies, the general intention, important design decisions, and related ontologies should be referenced; for a Web Service Capability, a brief natural language document is recommended. We refer to the VTA use case document as a reference for this style (see Section 3.1).
Finally, the technical issues addressed in the use case should be explained. We recommend that this subsection should give only a brief overview of the technical solution, and that more detailed explanations of the theoretical and the technical realization should be moved to a different document.
This section presents three use cases developed using WSMO. Each use case has a different focus. We briefly introduce the use cases here, and the use case modeling is provided in separate documents.
This use case models a B2C application scenario: a Virtual Travel Agency for purchasing train tickets provides a WSMO Web Service, and a customer defines a Goal for purchasing a train ticket.
Link: http://www.wsmo.org/2004/d3/d3.3/
This use case was the first WSMO use case developed, and dates from a very early stage of development of WSMO. The use case setting has deliberately been kept very simple, as the main aim was to develop the basic elements of WSMO without getting lost in arbitrary complex issues. Thus, the use case defines only a small set of WSMO resources: 4 modularized domain ontologies, 2 Goals, 1 Web Service, and preliminary versions of WSMO Mediators.
The use case has been updated and changed several times in earlier versions of this document. As it might be hard to understand the rationales for the changes, here is a short overview of the ‘history’ and related issues which have been addressed during the evolution of the use case:
In conclusion, this initial WSMO use case has proven to be very useful for the development of WSMO: it provided a real-world setting in which to explore the issues and challenges for Semantic Web Services technologies, thus enabling a clearer understanding of the whole enterprise and it has been used as a resource for recursive development of WSMO. Thus this use case has served a very useful purpose within the WSMO working group - although it might not strike readers as a particularly impressive “final solution” for Semantic Web technologies.
This use case models a B2B scenario for exchanging business documents. The intention is to develop this scenario more fully as time goes on, so for the moment there is only a placeholder document available at the following location:
Link: http://www.wsmo.org/2004/d3/d3.4/
This is the Use Case defined for Semantic Web Fred - an agent system for automated, cooperative goal resolution that uses WSMO. A virtual marketplace is defined, wherein buyers and sellers interact in order to satisfy their respective business deals.
Link: http://www.wsmo.org/2004/d3/d3.5/
Semantic Web Fred, SWF for short, is an environment for automated cooperation of agents on the Semantic Web that combines agent technology, ontologies, and Semantic Web Services. In SWF, software agents called Freds perform tasks automatically on behalf of their owners. According to the paradigm of agents as autonomously acting entities in a software environment, Freds have to interact in order to resolve their distinct tasks. Therefore, a Fred has to find a suitable cooperation partner as well as the computational resources required for automated task resolution. With regard to a service-oriented architecture as envisioned for Semantic Web Services, the main building blocks of SWF are Goals and Services. A Goal represents a task that a Fred is assigned, and a Service is a computational resource that allows automated resolution of Goals. SWF develops advanced mechanisms to identify possible cooperation partners, detect the services needed for automated goal resolution, and execute such cooperations between agents.The mechanisms for establishing cooperations between Fred-agents are realized by WSMO-enabled technologies. Therefore, a goal assigned to a Fred-agent is a WSMO Goal, and services in SWF are described as WSMO Web Services. On this basis, SWF realizes a cohesive set of mechanisms that detect suitable cooperation partners and services to be used, which increase the rate of successful cooperations.
The SWF use case defines an environment for testing and development of the SWF technology. All resources defined in this use case are WSMO resources - ontologies, as well as several goals and service descriptions. For this reason, this use case is considered to be a WSMO use case. The use case resources are provided in valid WSML according to WSMO v1.0, and are designed in such a way that reasonable cooperations can be estalished. Furthermore, the SWF use case provides a prototypical realization of the Web Service Discovery framework defined in WSMO D5.1, version 0.1.
More information on the SWF project can be found at the SWF project website at: http://www.deri.at/research/projects/swf/.
This deliverable presents WSMO use cases. Each use case addresses one or more specific technological issues related to Semantic Web Services, and elaborates a technical solution for this. The aim of the definition of use cases is to test and develop WSMO and WSMO enabled technologies; also, the definition of real-world use case scenarios allows recursive development of WSMO and WSMO-enabled technologies for Semantic Web Services.
In this document we have defined the general organization of WSMO use case documents, and we present existing use cases along with brief overviews of each use case. This deliverable is intended to evolve over time. The directions for future work in this deliverable are:
[He et al., 2004] he, H.; Haas, H.; Orchard, D.: Web Services Architecture Usage Scenarios, W3C Working Group Note 11 February 2004. Available at: http://www.w3.org/TR/ws-arch-scenarios/.
[Roman et al., 2004] D. Roman, U. Keller, H. Lausen (eds.): Web Service Modeling Ontology - Standard (WSMO - Standard), version 0.2 Available at http://www.wsmo.org/2004/d2/v02/.
The work is funded by the European Commission under the projects DIP, Knowledge Web, SEKT, SWWS, Esperonto, and h-TechSight; by Science Foundation Ireland under the DERI-Lion project; and by the Vienna city government under the CoOperate program.
The editors would like to thank to all the members of the WSMO working group for their advice and input into this document.
To facilitate tracking of changes between different versions of this deliverable, the following lists the key changes which occurred between one version of the document and the next. The change tracking begins with the most recent version of the document dated 11 November 2004, and works back to the version of 28 June 2004.
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