the need for a theory of modeling and simulation to support the m&s coi mission bernard p....
Post on 05-Jan-2016
220 Views
Preview:
TRANSCRIPT
The Need for a Theory of Modeling and Simulation to Support the M&S COI Mission
Bernard P. Zeigler, Ph.D.,Arizona Center for Integrative Modeling and Simulation
andJoint Interoperability Test Command
Fort Huachuca, AZ 85613-7051zeigler@ece.arizona.edu
Premise: Coordination is needed, theory can help
The M&S COI has partitioned its interests into metadata, mediation, and services, recognizing, at the same time, that applications will not break down neatly into these categories.
A framework is needed to • provide an ontology for M&S that recognizes the essential dynamic character of
simulation models,
• properly distinguish the elements in the M&S enterprise and the relationships that connect such elements in meaningful ways related to the objectives of simulation exercises,
• provide a rigorous mathematical theory that supports manipulations of the elements in their real-world incarnations in order to achieve the desired relationships
• enable us to – derive meaningful metadata schemes to characterize the identified elements– help delineate services amenable to web-based manipulation– provide well-defined semantics and pragmatics for cross-COI mediation.
Potential problems in the absence of an M&S COI Framework
• Lack of accepted terminology: multiple definitions for basic terms (model, simulation) make coherent vocabulary of metadata registry problematic
• Difficulties in composability of models and simulations come to the fore: WSDL characterizations of M&S service components are likely to break down when new orchestrations are attempted due to incompatibilities that can’t be represented at the interface level
• Central feature of M&S – dynamics (time behavior) – is the key impediment to easy interoperability of simulations as services
• others…
Where Theory of M&S Fits
M&SBody of
Knowledge
M&STheory and Framework
DoD Architectural Framework
MetaData
Mediation
Services
Start with Largest Perspective: M&S Body of Knowledge
• A Body of Knowledge (BOK) for modeling and simulation (M&S) provides a comprehensive and integrative view of the discipline
• A systematic top-down decomposition of M&SBOK – Definition: simulation is goal-directed experimentation using dynamic models
Tuncer I. Ören, Toward the Body of Knowledge of Modeling and SimulationInterservice/Industry Training, Simulation, and Education Conference (I/ITSEC) 2005
Core elements of supporting disciplines
mathematics, computer science, systems science, systems engineering
Core elements of M&S discipline• Input data• Models and modeling• Model processing• Experimentation• Model behavior• Behavior generation• Behavior processing• M&S infrastructure• Computerization• User/system interfaces• Reliability and ethics
M&S knowledge for application– science, engineering, business…
• Training, Education and learning• Development• Decision support• Understanding and Analysis• Entertainment Application types signal services that are likely to be of
interest to external users: other communities of interest (COI) with which M&S COI must interact
Concepts/terminology of supporting disciplinesare likely to be incorporated into M&S COImetadata characterizations or be in need of mediation
Theory of Modeling and Simulation provides anintegrating framework for these elements
M&SBOK provides “checklist” to enumerateM&S meta-data, mediation and services
M&S Framework and System Theory Support*
“Theory of Modeling and Simulation” (Zeigler, Praehofer and Kim, Academic Press, 2000)
Framework for M&S
Ontology delimiting entities andrelationships in M&S
Mathematical SystemsTheory
rigorous supports manipulating elements in their real-world incarnations to achieve the desired relationships
Mathematical Theory of Systems
• levels of system specification –are the levels of structure and behavior at which we can describe dynamic systems
• systems specification formalisms – these represent the types of models, such continuous and discrete, that modelers can use to build dynamic system models – a formalism specifies a subclass of systems
Levels of System Specification and Associated Morphisms:Formal Basis for Multiple Levels of Abstraction
Level Specification Name Two Systems are Morphical at this level if:
0 Observation Frame their inputs, outputs and time bases can be put into correspondence
1 I/O Behavior they are morphic at level 0 and the time-indexed input/output pairs constituting their I/O behaviors also match up in one-one fashion
2 I/O Function they are morphic at level 0 and their initial states can be placed into correspondence so that the I/0 functions associated with corresponding states are the same
3 State Transition the systems are homomorphic (explained below)
4 Coupled Component components of the systems can be placed into correspondence so that corresponding components are morphic; in addition, the couplings among corresponding components are equal
M&S Entities and Relations*
Real WorldReal World SimulatorSimulatorSimulatorSimulator
modelingrelation
simulationrelation
Each entity is represented as a dynamic system
Each relation is represented by a homomorphism or other equivalence
Data: Input/output relation pairs
structure for generating behaviorclaimed to represent real world
Device forexecuting model
Model
“Theory of Modeling and Simulation” (Zeigler, Praehofer and Kim, Academic Press, 2000)
M&S Entities and Relations (cont'd)
Real WorldReal World
modelingrelation
simulationrelation
Experimental frame specifies conditions under which the system is experimented with, observed and controlled
• captures modeling objectives• needed for validity, simplification justifications
SimulatorSimulator
Model
Experimental Frame
AbstractModel
Morphismsat
Structure Level
Morphismsat
Behavior Level
Morphismsat
Structure Level
Examples of the M&S theory that might be the basis for scaling up to the SOA
• Lockheed’s Model Base Repository
• Middleware Independent Distributed Simulation Protocol
• Semi-automated generation of standards conformance testing
Lockheed’s Managed Modeling Approach to DEVS-Based Modeling and Simulation
• DEVS – Discrete Event System Specification
– Formal discrete event specification.– Clearly separates Simulation Engine from
Models.– Object passing In-ports and Out-ports– Interchangeable Coupled & Atomic Models.– Strong support for reuse and composability.
• Multiple implementation are available.
• GUI development environments are available
• Active developer community distributed worldwide.
Joint MEASURE Advanced Simulation Development Tool for Systems of Systems
Joint MEASURE - Mission Effectiveness Analysis Simulator for Utility, Analysis and Evaluation
• Advanced Analyst-oriented GUI.
• Models SoS Engagement Domain.
• Platforms (how they move and react),
• Sensor (& networks),
• Communications (& networks),
• Weapons (& systems),
• C3 (at multiple levels).
• High Performance Simulation Engine
• Managed Software
• Full Complement of Integrated Tools
The Distributed Joint MEASURETM
Architecture
Logger
PropagatorPlatform
Sensors
Weapons
C3
Hull
Platform
Sensors
Weapons
C3
Hull
GIS
GIS dB
Logger
PropagatorPlatform
Sensors
Weapons
C3
Hull
Platform
Sensors
Weapons
C3
Hull
GIS
GIS dB
Hull Hull
HLA/RTI
Endomorphs Endomorphs
Joint MEASURE – Model Repository Reuse
Note presence of discrete and continuous dynamic model types
Use of infrared model in JCTS
project
“… the Lockheed-Martin activities may well represent the state of the art in complex model composability …”, Davis, Paul and Anderson, Robert in Improving the Composability of Department of Defense Models and Simulations, RAND, 2004
Prescriptive Requirements for Simulation Model Repositories *
* adapted from: ZEIGLER, B. P. 1997. A framework for modeling & simulation. Applied Modeling & Simulation:An Integrated Approach to Development & Operation, McGraw-Hill, New York.
Requirement In relation to Supports
building block components for application areas
defining a small number of “primitives” for synthesizing a wide variety of models for specific domain
expressabilityreusability
hierarchical modular model construction
enabled by “self-containedness” with input/output ports, both for building block components and models resulting from coupling
composabilitycomplexity management
coupling templates standardized means to couple the building blocks
interoperability
experimental frame base indexing
supports discovery of frames instantiated in the model base that are closely related to a desired frame for given objectives
meta data characterizationdiscovery
accommodate multiple formalisms in a manner satisfying the previous requirements
enable using different types of models with specific semantics, advantages, and limitations
expressabiltyinteroperability
Network
DEVS Simulator
DEVS Model
Middleware
Syntactic
Semantic
TechnicalInteroperability
Pragmatic
Conceptual
Tolk’s Levels
DEVS Simulator
DEVS Model
Middleware
SystemsArchitecture
DEVS component models are correctly integrated into a higherlevel coupled model by the DEVS simulator protocol
Middleware-Independent Simulation Architecture for SOA Infrastructure
Parallel and sequential simulation of the same DEVS model will always produce the same resultsThis is a strong proof of correctness that no logical-processor-based proof has been able to rival.
DEVS Model Continuity as Basis for Life Cycle Development of Web Services
Service Discovery: UDDI
DEVS Distributed Executor
DEVS Model
Sevice Description: WSDL
Packaging:XML
Messaging:SOAP
Communication: HTTP
SOA
DEVS Simulator
DEVS Model
Pre-test of ConceptualModel in non-distributedenvironment
Refine and Transfer model to distributedenvironment
DEVS Distributed Simulator
DEVS Model
Packaging:XML
Messaging:SOAP
Communication: HTTP
• Change engine•Provide meta-data forWeb presence as service
The model can remain basically invariant as it is transitioned through the phases from conception to realization
Model-Driven Development (MDD)* for SOA(Service Oriented Architecture)
• Organizations must integrate MDD into the development process for distributed, heterogeneous, loosely coupled service environment
• Models – represent the problem domain– raise the level of abstraction– serve as blueprints – drive the development process
• Facilitate creating and managing complicated systems– Use/Re-use model-based code generators – Accelerate/Automate the software life cycle– Transition study of systems capable of expansion and evolution – Reduce manual work required in development and testing
• Deliver higher-quality service components
*Anne T. Manes, Burton Group Pub.
Summary: Dynamic Systems and Semantics
• Dynamics are a major component in the semantics of simulation models
• Dynamic properties must be represented in schemes for semantic layers of model interoperability
• Model formalisms key in on different features of dynamics (e.g., continuous, discrete event)
• Multiple formalisms need to be managed in any M&S repository supporting reusability and composability
Summary: DEVS-based SOA Development
• Simulation Model framework supported by:– Systems Theory-based – Formal, allows proofs of correctness and other properties– Dynamics – integrates model formalisms in one theory and
framework
• Modularly separates – Model– Simulator– Experimental Frame
• Model Continuity supports development life cycle
Theory of Modeling and Simulationas Framework for M&S COI
• Formally characterizes the elements and relationships to support discovery, interoperability and composability
• Ontology identifies the elements as dynamic systems within mathematical systems theory
– well-defined levels of behavior and structure specifications– relationships are made operational by appropriate morphisms– rigorous mathematical theory supports orchestration of components
• Provides the basis for metadata schemes that are unambiguous and compatible with the vocabulary and concepts of the theory
– expose the proper elements for efficient discovery – reuse of M&S data and services.
Results: • solid foundation for a well-defined semantics and pragmatics
of the M&S enterprise• well-defined infrastructure for SOA development
Bernard P. Zeiglerzeigler@ece.arizona.edu
ACIMSwww.acims.arizona.edu
Contact:
More information:
Other Presentations
• Standards Conformance Testing as an M&S Web Service
• The Special Role of M&S in Cross-COI Mediation
• M&S Services at the Crossroads of Service Oriented Architecture and the DoD Architectural Framework
top related