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

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DEVS a Formal, Theory-Based, Technology-Independe
nt Standard for Distributed Simulation

• James Nutaro
• Bernard P. Zeigler
• Hessam Sarjoughian
• ACIMS
• Gabriel Wainer
• SISO DEVS Standards Working Group
• I/ITSEC
• Special SCS Session on Standards for MS

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Modeling Simulation/Systems Theory
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MS Framework
Objectives represented by
Layered architecture
Entities formalized as systems relations as
system morphisms
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DEVS Modeling Simulation Framework

• DEVS Discrete Event System Specification
• Provides sound MS 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

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DEVS Atomic Model
Make a transition (internal)
Make a transition (external)
input
State
internal
external
Send an output
time advance
Handle input
output
output
Hold for some time
Pulse Generator
time
interPulseTime gt0
Output
Pulse Generator
start
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DEVS Hierarchical Modular Composition

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

Coupled composed of one or more atomic and/or
coupled models
hierarchical construction
coupling
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Types of Models and their Formalisms
Coupled Models
Atomic Models
Partial Differential Equations
Ordinary Differential Equations
Processing/ Queuing/ Coordinating
Networks Collaborations
Physical Space
Phase Based Models
Pulse Based Models (varGen, Sum)
Digraph Models
1,2 Dim Cell Space
Discrete Time/ Automata
Quantum Based Models (DEVS Integrator, instantane
ous Functions
Cellular Automata
can be components in a coupled model
2 Dim State Space
1 Dim State Space
Self Organized Criticality Models
Multi Agent Systems
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Scalability, Flexibility and Inter-operability
Through Interface Standardization
DEVS Simulation Protocol
Single processor
C
Java
Distributed Simulator
DEVS
Simulator
Other Representation
Real-Time Simulator
Non DEVS
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For more literature, software, tutorials,

• Arizona Center for Integrative
• Modeling Simulation
• (ACIMS)
• www.acims.arizona.edu