DEVS-Based Simulation Web Services for Net-Centric T&E

Saurabh Mittal, Ph.D.Jose L. Risco-Martin*, Ph.D.

Bernard P. Zeigler, Ph.D.

Arizona Center for Integrative M&S, Univ. of Arizona*Departamneto de Arquitectura de Computadors y Automatica,

Madrid, Spain

Outline

Need for Net-centric M&S paradigm Position of DEVS in addressing capabilities Components of Net-centric M&S Underlying technologies

DEVS, XML, Web Services, DEVSML Distributed simulation using SOADEVS SOADEVS Client Demonstration Conclusions and Future work

Need for Net-centric M&S Paradigm

Acute need for a new testing paradigm that could provide answers to several challenges in a 3-tier structure Tier 1: individual systems or programs Tier 2: SoSs in which interoperability is critical Tier 3: Enterprise level, where joint and collaborative

operations are conducted

The paradigm has to comply with Department of Defense Architecture Framework (DoDAF). Unfortunately, DoDAF and other DoD net-centric

mandates post significant challenges to current testing and evaluation tools

State of DEVS Technology

Desired M&S Capability for T&E

Solutions Provided by DEVS Technology

Support of DoDAF need for executable architectures using M&S

DEVS Unified Process [31] provides methodology and SOA infrastructure for integrated development and testing, extending DoDAF views

Interoperability and cross-platform M&S using GIG/SOA

Layered Simulation architecture for interoperability testingNet-centric composition and integration of DEVS ‘validated’

models using Simulation Web Services

Automated test generation and deployment in distributed simulation

Model and Simulator separatedBifurcated Test and Development process

Test artifact continuity and traceability through phases of system development

Model-Continuity principles

Real time observation and control of test environment

Variable-structure component modeling to enable control and reconfiguration of simulation on the fly

Dynamic simulation tuning, interoperability testing and benchmarking.

Components of Net-Centric M&S

Every web-based simulation consists of: The Application Model Partitioner Model Deployer Model Initializer Model Simulator

Many examples exist that implement above steps but in different manner: DEVS/P2P, DEVS/RMI, DEVS/CORBA

Most are focused towards simulation engine Our effort is more oriented towards application layers i.e.

the modeling application itself

Underlying Technologies

DEVS Based on mathematical formalism using system

theoretic principles Separation of Model, Simulator and Experimental

Frame Atomic and Coupled types Hierarchical design

Web Services using XML Service Oriented Architecture (SOA) consists of

various W3C standards Machine-to-machine interoperable interaction over the

network based on WSDL interface descriptions Client server framework Message encapsulated in SOAP wrapper which is in

XML

Underlying Technologies …contd’

DEVSML Built on JavaML, which is XML representation of

Java Behavior representation takes its power from

underlying JavaML

DEVSML and SOADEVS

Distributed Simulation using SOADEVS Fundamental Objective: Integrate software

application as services Two layer service framework User layer

Upload, Compile, Simulate (centralized or distributed)

Engine layer Initialize, DEVS-protocol relation services, exit,

console output retrieval service

Engine Layer:•Initialize simulator i•Run Transition in simulator i•Run Lamda function in simulator i•Inject message to simulator i•Get tN from simulator i•Get ta from simulator i •Get consoleLog from all simulators•Finalize simulation service

Distributed Simulation using SOADEVS … contd’

Distributed Simulation using SOADEVS … contd’ Abstraction of Coupled Model with an Atomic

Model having DEVS State Machine

Distributed Simulation using SOADEVS … contd’ Centralized Simulation

Distributed Simulation using SOADEVS … contd’ Real-time Distributed Simulation

Involves direct coupling with machines

RTCOORDINATOR

(Waiting)

RT SIMULATION

SERVICE

RT SIMULATION

SERVICE

RT-SIMULATOR RT-SIMULATOR

0.- nextTN

1.- nextTN 2.- Message

3.- Messageserialized

4.- MessageDeserialized

InternalTransition

ExternalTransition

OutputPropagation

0.- nextTN

SOADEVS Client

A Demonstration

DEVS Unified Process and SOADEVS

Conclusions

A SOA-oriented framework called SOADEVS for test and evaluation of DEVS models

Centralized and Distributed executions Modified real-time DEVS simulation protocol

to be tailored for SOA Layered service architecture with underlying

helper services Part of the larger DEVS Unified Process

(DUNIP) Communication using XML as middleware

A means towards an end

Future Work

Net-ready capability testing requirements Execution of DEVS test-models in tandem with

real web services over SOA Multi-platform simulation capability

DEVSJAVA and DEVS/C++ together in a single simulation session interfaced using WSDL specifications of layered SOADEVS

Platform Specific Messages (PSMsg) translated to Platform Independent Messages (PIMsg) at run-time using DEVSML architecture

COORDINATOR(Waiting)

SIMULATIONSERVICE

DEVSJAVA

SIMULATIONSERVICE

DEVS-C++

SIMULATORDEVSJAVA

SIMULATORDEVS-C++

0.- nextTN

1.- nextTN 2.- PSMsg

3.- PIMsgserialized

4.- PSMsg’InternalTransition

ExternalTransition

OutputPropagation

0.- nextTN