**3.1 Experimental environment**

In order to support this model-driven domain ontology modelling approach, Borland Together (Borland, 2006), a famous MDA tool, is employed in our experiment. By using UML extension mechanism, we implemented the UML Profile for RDF and OWL in Borland Together. In addition, Borland Together tool enable the model-to-model transformation, and this facilitates the transformation from PIM to PSM. Through the developed model-to-code transformation engine, we realize the transformation from PSM to ontology file encoded by OWL. At last, in order to verify whether the transformation is correct or not, the generated OWL file is imported in Protégé tool to test. By the experimental verification, the proposed model-driven ontology modelling approach can nicely support the constructing methodology of telecommunications service domain ontology.

Under the guidance of this approach, our research team has created a telecommunications service domain ontology knowledge repository which consists of around 430 telecommunications services-related ontology concepts/terminologies and 245 properties. Currently, these ontologies are published on our website (BUPT, 2009), see Figure 21.

description model triples (C, R, G). The states, input events and transformation function of the automaton correspond to the class nodes, relation nodes and relation matrix set respectively in PSM class graph. The begin state of automaton is the owlClass node or objectProperty/datatypeProperty node in class nodes and the terminate states set includes all class nodes whose out-degree are zero and all nodes have been transformed by the

The model transformation regulation table defines the transformation regulation from UML Profile for RDF and OWL to OWL language. In the states jump process of model transformation automaton, corresponding regulation is used to perform model transformation. In the process of formulating the transformation regulation, the relations between every label node should be unified, which makes the regulation can be formulated depending on the OWL label structure and the relations between UML model elements.

Model output module only stores the formalized result of the transformation to the appointed path. And in order to verify the validity of the OWL file transformed, user can import the generate code into protégé tool for verification. Protégé is an ontology editor developed by Stanford University, which represents the OWL structure in graphic interface

By using the above mentioned model to code transformation approach, the PSM of Figure

In this section, we describe our experimental environment, the implemented service use case and present the obtained evaluation results to validate the semantic interoperability enabled

In order to support this model-driven domain ontology modelling approach, Borland Together (Borland, 2006), a famous MDA tool, is employed in our experiment. By using UML extension mechanism, we implemented the UML Profile for RDF and OWL in Borland Together. In addition, Borland Together tool enable the model-to-model transformation, and this facilitates the transformation from PIM to PSM. Through the developed model-to-code transformation engine, we realize the transformation from PSM to ontology file encoded by OWL. At last, in order to verify whether the transformation is correct or not, the generated OWL file is imported in Protégé tool to test. By the experimental verification, the proposed model-driven ontology modelling approach can nicely support the constructing

Under the guidance of this approach, our research team has created a telecommunications service domain ontology knowledge repository which consists of around 430 telecommunications services-related ontology concepts/terminologies and 245 properties.

Currently, these ontologies are published on our website (BUPT, 2009), see Figure 21.

and makes the verification of OWL code validity more quickly and conveniently.

18 is transformed into the corresponding ontology encoded by OWL like Figure 20.

**3. Experimental environment, use cases and evaluation** 

methodology of telecommunications service domain ontology.

And good regulation is easy to extend in the future.

by telecommunications service domain ontology.

**3.1 Experimental environment** 

*2.2.5.2.4 Model output module* 

automaton.

Fig. 20. A part of formal network ontology encoded by OWL.

Telecommunications Service Domain Ontology:

**3.3 Lessons learned** 

using URIs and RDF.

service integration.

**4. Conclusion** 

representations of telecommunication and Internet services.

Semantic Interoperation Foundation of Intelligent Integrated Services 207

Based on this domain ontology, we described the telecom network capability services in the semantic level to validate its feasibility. We apply the semantic web service and ontology technologies to the telecommunications service domain, and present an infrastructure to enable the semantic interoperability of telecom network and Internet in the service layer (Qiao et al., 2008b). The proposed approach improves the accuracy of telecommunication network services description, discovery and matching, and unifies the semantic

Currently, under the shift trend from Web2.0 to Web3.0 era, there have been some initial semantic web applications in Internet field. For example, the system of Twitter allows tweets to be tagged with information that will not appear in the message but can be read by computers (Twitter, 2010). Google is using structured data open standards such as microformats and RDFa to power the rich snippets feature. It's an experimental Semantic Web feature (Google, 2010). FOAF (Friend of a Friend) (FOAF, 2010) is a machine-readable ontology describing persons, their activities and their relations to other people and objects. As a "practical experiment" in the application of RDF and Semantic Web technologies to social networking, FOAF is becoming more and more popular now (FOAF, 2000). In addition, Linked Data (Linked Data, 2007) is a recommended best practice for exposing, sharing, and connecting pieces of data, information, and knowledge on the Semantic Web

However, the semantic web applications in telecommunication services domain are still in an early research phase. Although RDF-based CC/PP (Composite Capability/Preference Profiles) (W3C, 2007) and UAProf (User Agent Profile) (OMA, 2001) are used to describe the terminal capability and user preference, other practical applications are very rare. Therefore, in order to eliminate the semantic gap between telecom network and Internet, the research on semantic web applications in telecommunications field still need to be further enhanced. Telecommunications service domain ontologies consist of various domain related concepts and knowledge, which is the base of semantic interoperability. The wide acceptance of standards and common practices of telecommunications service domain ontologies are still a way ahead. The promotion of the telecommunications service domain ontology by related standardization organizations would be in the foundation for the semantic interoperability of heterogeneous communications equipments and the industrial practical convergent

The network heterogeneity and service convergence are the main characteristics of future network. The provision of self-adaptive intelligent integrated services has become the pursuing goal of network carriers and value-added service providers. Dynamic discovery and composition of services are the important enabling technologies for self-adaptive integrated services. In the service discovery and composition process, semantic interoperability is a key issue. Actually, ontology, as a semantic interoperability and knowledge sharing foundation, has obtained more and more attentions. However, telecommunication service field consists of a large number of concepts/terminologies and

Fig. 21. The published telecommunications service domain ontology.

#### **3.2 Use cases: Semantic telecommunications network capability services**

In order to support the shift from traditional closed business model to open service ecosystem of telecom industry, NGN (Next Generation Network) and 3G network all adopt the open API (Application Programming Interface) technologies in the service layer, such as Parlay/OSA and Parlay X (Moerdijk & Klostermann, 2003). Thus, the telecommunication network services, such as call control, short messaging service, and location service, are available to the service developers in the form of APIs. This facilitates the value-added service development. With the development of distributed computing technology, Service-Oriented Architecture (SOA) is also imported into the telecommunications service domain by Parlay Web Service specifications. However, the open interface specifications of telecommunication networks are currently still in the syntactic level. As WSDL (Web Services Description Language)-based telecommunication network services lack the rich semantic annotation information, the keyword-based service matching cannot enable an accurate service discovery. So, currently value-added services often directly invoke the needed telecom network services provided by a specific network carrier. This results in the tight-coupling of application logic and service resources, which limits the provision of dynamically self-adaptive services. The applications cannot dynamically discover satisfied telecom network services and compose them according to the context environment. Facing the heterogeneous networks and personalized user demands, the self-adaptation has become a very important feature of future intelligent integrated service. Therefore, the semantic interoperability of telecom network and Internet in the service layer should be considered.

Based on this domain ontology, we described the telecom network capability services in the semantic level to validate its feasibility. We apply the semantic web service and ontology technologies to the telecommunications service domain, and present an infrastructure to enable the semantic interoperability of telecom network and Internet in the service layer (Qiao et al., 2008b). The proposed approach improves the accuracy of telecommunication network services description, discovery and matching, and unifies the semantic representations of telecommunication and Internet services.
