Military Communications and Information Technology: A Trusted ...

Military Communications and Information Technology: A Trusted ... Military Communications and Information Technology: A Trusted ...

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246 Military Communications and Information Technology... Figure 4 Properties of InsigmaEvent class IEO, based on T-Box and A-Box statements, classifies event source to one of the following types of event: • Road Accident, • Traffic Collision, • Traffic Difficulties, • Weather Difficulties. Classifying and inferring knowledge is provided by the RM described in the next chapter. V. Reasoning Module A. Architecture The RM is one of the parts of ENS. It holds whole “logic” and decides about the type of event and necessary actions to be triggered. The knowledge inferred on the basis of the T-Box and A-Box ontology statements is used by the ENS dispatching module to send appropriate notifications. RM was implemented in Java as a Web Service. This implementation uses the following tools and libraries: • Protege-owl-3.4.6 – ontology development and modeling tool, • Pellet 2.2.2 –OWL reasoner provides reasoning services for OWL ontologies [11], • Jess71p2 – rule engine for the Java platform [12], • Glassfish 2.x – application server for the Java EE platform. Ontology development was done using Protégé 3.6.4 with OWL 1.0. We decided to use the older version of Protégé due to the fact that the newest version (4.2) did

Chapter 3: Information Technology for Interoperability and Decision... 247 not support some of the libraries that were important in the process of ontology application like e.g. Protégé OWL API. This library has an important plugin which enables to generate java code form OWL classes which is useful while exploiting ontologies at run-time. Figure 5. Reasoning module interface to the Communication Module of ENS In general, existing implementation of the reasoning engine performs a set of operations on the ontology, e.g.: • filling in the domain model with event descriptions, • extending an ontology with SWRL rules, • reasoning and classifying knowledge, • querying an ontology about knowledge contained into the domain model by using the queries described in Semantic Query-Enhanced Web Rule Language (SQWRL). The RM after being invoked creates an object of the OWLModel class on the basis of event.owl ontology ; creates an object of the MyFactory class to fill in the ontology with instances; creates an instance of Protégé Pellet Reasoner; checks consistency of the created OWL model; classifies ontology; loads SWRL rules and invokes Jess rule engine; creates an SQWRL queries and returns the response. InsigmaEventOntology service implements Web Method called send- EventDescription used to invoke reasoning engine. Event description is used by the RM to infer knowledge. These are the following information (A-Box statements): kind of event, injured person in the event and result of the event (see example of simple SOAP request in Fig. 6). For the reasoning purposes we decided to use Pellet reasoning engine. The reasoner provides classification that compute complete class hierarchy, consistency checking (checking possibility for a class to have any instances) and finding the most specific classes that an individual belongs to.

Chapter 3: <strong>Information</strong> <strong>Technology</strong> for Interoperability <strong>and</strong> Decision...<br />

247<br />

not support some of the libraries that were important in the process of ontology<br />

application like e.g. Protégé OWL API. This library has an important plugin which<br />

enables to generate java code form OWL classes which is useful while exploiting<br />

ontologies at run-time.<br />

Figure 5. Reasoning module interface to the Communication Module of ENS<br />

In general, existing implementation of the reasoning engine performs a set<br />

of operations on the ontology, e.g.:<br />

• filling in the domain model with event descriptions,<br />

• extending an ontology with SWRL rules,<br />

• reasoning <strong>and</strong> classifying knowledge,<br />

• querying an ontology about knowledge contained into the domain model<br />

by using the queries described in Semantic Query-Enhanced Web Rule<br />

Language (SQWRL).<br />

The RM after being invoked creates an object of the OWLModel class on<br />

the basis of event.owl ontology ; creates an object of the MyFactory class to<br />

fill in the ontology with instances; creates an instance of Protégé Pellet Reasoner;<br />

checks consistency of the created OWL model; classifies ontology; loads SWRL rules<br />

<strong>and</strong> invokes Jess rule engine; creates an SQWRL queries <strong>and</strong> returns the response.<br />

InsigmaEventOntology service implements Web Method called send-<br />

EventDescription used to invoke reasoning engine. Event description is used<br />

by the RM to infer knowledge. These are the following information (A-Box statements):<br />

kind of event, injured person in the event <strong>and</strong> result of the event (see<br />

example of simple SOAP request in Fig. 6).<br />

For the reasoning purposes we decided to use Pellet reasoning engine. The reasoner<br />

provides classification that compute complete class hierarchy, consistency<br />

checking (checking possibility for a class to have any instances) <strong>and</strong> finding the most<br />

specific classes that an individual belongs to.

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