DEVS: a Formal, Theory-Based, Technology-Independent Standard for

Distributed SimulationJames Nutaro

Bernard P. ZeiglerHessam Sarjoughian

ACIMS

Gabriel WainerSISO DEVS Standards Working Group

I/ITSECSpecial SCS Session on Standards for M&S

Mathematical SystemsTheory

Hierarchy of System

Specifications

Framework forModeling and

Simulation

Hierarchy of SpecificationMorphisms

entities

relations

uses the formalism of

is interpreted by

Modeling & Simulation/Systems Theory

M&S Framework

Network

Simulation

Modeling

Search

Decision

Collaboration

DEVS

HLAModel

Real WorldReal World SimulatorSimulator

modelingrelation

simulationrelation

Experimental Frame

Objectives represented by

Layered architecture

Entities formalized as systems; relations as system morphisms

• DEVS = Discrete Event System Specification

• Provides sound M&S framework

• Derived from Mathematical dynamical system theory

• Supports hierarchical, modular composition and reuse

• Can express Discrete Time, Continuous and hybrid models

• Event-orientation enables efficient simulation

• Object-oriented, Distributed, Real-time Implementations

DEVS Modeling & Simulation Framework

State

output

external internal

time advance

Make a transition(external)

Make a transition(internal)

Handle input

Send an output

Hold for some time

input

output

DEVS Atomic Model

receptive refractInput

fire

Firing delay >0

Output Fire-once Neuron

PulseGenerator

out

time

passive activestart

interPulseTime >0Output Pulse Generator

external event Internal event output event

DEVS Hierarchical Modular Composition

Atomic: lowest level model, contains structural dynamics -- model level modularity

Atomic

Atomic Atomic

Atomic

+ coupling

Atomic

Atomic

Atomic

Coupled: composed of one or more atomic and/or coupled models hierarchical

construction

Atomic Models

OrdinaryDifferentialEquations

Pulse BasedModels

(varGen, Sum)

Quantum Based Models

(DEVS Integrator,instantaneous

Functions

Coupled Models

Phase BasedModels

Cellular Automata

1,2 Dim Cell Space

PartialDifferentialEquations

Self Organized Criticality

Models

Processing/Queuing/

Coordinating

DigraphModels

NetworksCollaborations Physical

Space

1 Dim State Space

2 Dim State Space

Types of Models and their Formalisms

can becomponents in a coupled model

MultiAgent

Systems

Discrete Time/

Automata

Scalability, Flexibility and Inter-operability Through Interface Standardization

Simulator

Single processor

DistributedSimulator

Real-TimeSimulator

C++

NonDEVS

DEVS

Java

OtherRepresentation

DEVS SimulationProtocol

Arizona Center for Integrative

Modeling & Simulation

(ACIMS)

www.acims.arizona.edu

For more literature, software, tutorials,…