THE SUPPORTING ROLE OF ONTOLOGY IN A

SIMULATION SYSTEM FOR COUNTERMEASURE

EVALUATION

Nelia LombardDPSS, CSIR

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?

Introduction

Contents

What is an OntologyThe Countermeasure Simulation SystemPossible Role of Ontology in the Simulation

SystemConstructing the OntologyLessons Learned Conclusions and Future Development

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

countermeasuresOryx can hover

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.

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

The Countermeasure Simulation System

Purpose: Evaluate countermeasure

designDetermine aircraft

vulnerability

Simulate the interaction between models as results of specific events

Use realistic models

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

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>

The Countermeasure Simulation System

• Simulation results processed to show effectiveness of countermeasure against threat

• Results:

– 3D Viewer – Videos

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

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

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

Creating the Ontology (2)

Create individuals

Specific objects used in the simulation Target: Oryx Atmosphere: Fog Countermeasure: Flare Scenario: ScenarioFlareLeftOryx200ft30kn

Classes in the Ontology

Object Properties

Data Properties

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

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

Commentary

Questions? Suggestions Input