Model Composability Through Base Object Models BOMs

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Model Composability Through Base Object Models
(BOMs)
FOM
Federate
Federation
Composability The capability to select and
assemble components in various combinations into
complete, validated simulation environments to
satisfy specific user requirements across a
variety of application domains, levels of
resolution, and time scales Dr. Mikel Petty
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Topics

• Background
• What is a BOM?
• History
• Rationale / FEDEP Piece-Part Approach
• BOM Concept
• BOM Basics
• BOM Example
• BOM Development/Standardization Effort
• Summary

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Background What is a BOM?

• a component-based standard for describing a
  reusable piece part of a federation or an
  individual federate.
• characterizes elements of a simulation and
  relationships among conceptual entities within a
  simulation environment as a language neutral
  interface.
• BOMs can be used to document the interface for
  one or more of the following piece part elements
  
• Object classes
• Interaction classes
• Patterns of interplay
• State machines
• Events

• BOM functionality intended to be supported
  independently
• Separates a piece parts interface and its
  implementation allowing composability to be
  supported across a wide range of hardware
  platforms, operating systems and languages.
• Provides developers and users a modular approach
  for defining and adding new capabilities to a
  federate or federation, and in quickly composing
  object models such as HLA FOMs and SOMs through
  BOM Assemblies.

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History
2004
1998
2002
2000
2003
2001
1996
2010
1999
2005

BOMPDG
ReferenceFOM Study Group
BOM Study Group
HLA 1516Evolve
FEDEP PDG
Rapidly composableand scalable MS
RPR FOM
BOM PN
BOM Methodology Strawman
FOMpiece parts (FEDEP, OMT)
SRML
HLA1516
CMSE

• Tools
• Components
• Libraries

As long as things are created from scratch,
growth can be at most linear
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History - Involvement
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Background (1/2)
Model Composability
System Composability
FEDEP

• Development / integration frustrations
• Required time, effort and collaboration it takes
  to formulate a FOM
• Required refactoring of a federate to comply with
  FOM,
• Many things commonly recreated / repeated one
  federation development effort to the next
• DESIRE to reuse and integrate common
  piece-parts that should go into a FOM
• object classes,
• interaction classes,
• relationships commonly found among conceptual
  entities that are supported by object classes and
  interaction classes,
• intended use (i.e., purpose)
• resharing of experience

• HURDLES
• Knowing what to look for within the problem
  domain space in which a conceptual model should
  be engineered
• Knowing how to capture the various conceptual
  models that represent the domain space
• Developing / selecting an appropriate Federation
  Object Model based on conceptual model

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Background (2/2)
Model Composability
System Composability
FEDEP
Conceptual Models
Plug Play Systems
Reusable Piece-Parts
Federate Capability (SOM Level Support)
Federation Agreement(FOM Level Support)
BOMs are designed for enabling

• Composability
• Extensibility
• Exchangeability

• Manageability
• Understandability

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BOM Basics
The BOM is an open standard approach for
describing a reusable component or piece part of
a simulation or system, which represents or
supports a pattern of interplay.

• Interface
• essential elements provided by a component or
  piece-part
• Template standard (SISO PDG)
• language neutral notation (XML)
• Implementation
• Component / piece-part functionality captured /
  contained independently
• Examples
• Source code / federate code,
• Interpreted code
• SRML / JavaScript
• Byte Code (java)
• Binary Object
• Windows DLL,
• COM (ActiveX),
• Unix DSO, or
• Benefits of interface/implementation separation
• allows BOMs to serve as building blocks for
  supporting composability
• Includes the composition of
• object models,

A BOM separates component / piece-parts
interface from its implementation
BOM Elements
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BOM Example Weapon Fire

• Weapon Fire is a frequent Pattern of Interplay
• Derived from a RPR FOM decomposition
• Can be captured in a reusable way using BOM
  template

Pattern of Interplay - Sequence of activities
related to one or more conceptual entities
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BOM Example Model Identification

• This is the metadata
• Leveraged elements from HLA OMT, Dublin Core,
  DDMS, VVA RPG
• Helps make components/piece-parts meaningful!

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BOM Example Pattern Description

• Composed of a collection of actions
• Describe the activities which transpire among the
  conceptual entities being modeled
• Each action supported by events or other BOMs
• Includes support for variations and exceptions

An action can be associated to an event
An action can be potentially supported completely
by another pattern of interplay
Pattern
n
1
1
Action
Event
BOM
n
n
Trigger
Message
Source
Target
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BOM Example Messages

• Directed Events
• Sent using HLA attributes or interactions
  addressed to receiver(s)

Receive Message and react to its contents
Send Message

• Note Events can be identified by Pattern actions

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BOM Example Triggers

• Undirected Events
• Published using HLA attributes or interactions.
• Sender does not know about the receiver.

• Note Events can be identified by Pattern actions

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BOM Example State Machine
State Machine
n
States
n
NextState
ExitCondition
PatternAction
The use of interaction classes involves a
detailed understanding of the state transitions
and timing between events. - RPR FOM GRIM
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Summary

• BOMs help enable rapid development of
  interoperable simulation components and
  federations promoting reuse, interoperability and
  composability
• Separating interface from implementation allows
• Components with similar specifications to be
  interchangeable and independently upgradeable
• Developers can customize the appearance and
  behavior of components along predetermined
  dimensions
• Components / piece-parts to be combined to form
  larger-grained components as well as complete
  applications
• BOM Metadata
• Facilitates the discovery and cataloging of
  common patterns
• Encourages the development and reuse of certified
  components
• Enables rapid development of federations and
  federates in a cost-effective manner