THE SUPPORTING ROLE OF ONTOLOGY IN A SIMULATION SYSTEM FOR COUNTERMEASURE EVALUATION Nelia Lombard DPSS, CSIR

1. THE SUPPORTING ROLE OF ONTOLOGY IN A SIMULATION SYSTEM FOR COUNTERMEASUREEVALUATIONNelia LombardDPSS, CSIR

2. Introduction • Ontologies and Simulations • What are the possible advantages that an ontology might have in the simulation environment? • Can an ontology provide solutions to some of the challenges to be dealt with in the countermeasure simulation system?

3. Contents • What is an Ontology • The Countermeasure Simulation System • Possible Role of Ontology in the Simulation System • Constructing the Ontology • Lessons Learned • Conclusions and Future Development

4. What is Ontology? • Study the meaning of being • How an object relates to the world and to itself • Describes the world • Not a taxonomy Taxonomy: Oryx->Helicopter->Aircraft->Transport Ontology: • Oryx has countermeasures • Oryx can hover

5. Ontology in Information Systems and Computing • The artifact present, in a formal way, the knowledge of a domain as a set of concepts and relationships between the concepts, for the purpose of reasoning.

6. Use of Ontologies • Share a common understanding of the structure of information and the concepts • A common vocabulary • Enable reuse of the domain knowledge • For example, time ontology • Make domain assumptions explicit • Separate domain knowledge from the operational knowledge • Analysis of domain knowledge

7. The Countermeasure Simulation System • Purpose: • Evaluate countermeasure design • Determine aircraft vulnerability • Simulate the interaction between models as results of specific events • Use realistic models

8. The Countermeasure Simulation System • The Simulation Scenario • Type of aircraft: e.g. Oryx • Flight plan: How will the Oryx fly? • Type of missile threat • Type of countermeasure and the dispensing logic • Atmospheric conditions: e.g. clear skies or fog • Terrain model

9. The Countermeasure Simulation System • Extensible Markup Language (XML) is a set of rules for encoding documents in machine-readable format • Model parameters are set up in XML files • Simulation output written to XML files <Scenario> Name=”TestPoint1” <Movings> <Moving> FileName =”Oryx.xml” Type=”DPSSORYX” /> </Movings> <Observers> <Observer> FileName=”ThreatType1.xml” Type=”BaseMissile” /> </Observers> <Atmosphere> FileName=”Atmo.xml” /> </Scenario>

10. The Countermeasure Simulation System • Simulation results processed to show effectiveness of countermeasure against threat • Results: • 3D Viewer • Videos

11. Possible Role of Ontology in the Countermeasure Simulation System • To know what is available in the system • Guideline for new models • High-level description • Verify and validation of scenarios • Reverse engineer previous simulations

12. Constructing the Ontology • Where will it be used? • How can it add benefit? • Purpose • To capture concepts in a simulation scenario • Scope • A Simulation Scenario

13. Creating the Ontology (1) • Identify the classes • Scenario, Target, Threat, Atmosphere, Countermeasure • Define object properties • Relationships between classes • Target has countermeasure • Scenario has target • Define data properties • Position, Velocity

14. Creating the Ontology (2) • Create individuals Specific objects used in the simulation • Target: Oryx • Atmosphere: Fog • Countermeasure: Flare • Scenario: ScenarioFlareLeftOryx200ft30kn

15. Classes in the Ontology

16. Object Properties

17. Data Properties

18. Ontology: Lessons Learned • Naming of classes • Consistency • Agreement • Classes versus instances • Match the real world • Modeling roles as classes • Classes can loose their roles over time

19. Conclusions • Clear, common understanding of what is in the domain • High-level description • Capture the meaning of objects • Future functionality: Use ontology to set up scenario and to reason about validity of scenario

20. Commentary Questions? Suggestions Input