BOM Experimental 2010 Schema now available!
It has been four years now since the standardization of the Base Object Model (BOM) within SISO.  Over the past four years a SISO Product Support Group (PSG) has supported and analyzed how BOMs have been used to support conceptual modeling and object modeling for Modeling and Simulation (M&S) and System Engineering projects.  While, the BOM standard has very effective, there are some areas of improvement that have been identified.  The result is a new experimental schema to consider for future BOM Product revision.
Several enhancements have been incorporated into this new schema including the following:

  • Conceptual Model now Conceptual Definition
    • Pattern, State Machine “containers”
    • Conceptual Entity / Event Composability
      • Characteristic “Has-A” conceptual entity/event now supported
      • Used to show what an abstract entity/event embodies
    • Mappings folded into the Conceptual Entity / Event,
      • Reduces excess / redundant information
      • Used to link known classes that can support Entity/Event
  • Object Model now Class Definition
    • Architecture independent; relaxed “HLA” constructs
    • Object Class now identified as Persistent Class
    • Interaction Class now identified as Transient Class
    • Added extensions place holder for HLA, TENA, CTIA, DIS specific characteristics
    • More reusable classes; removed nested object classes / interaction classes and replaced with linked data to parent(s).
  • Element can be marked with community related taxonomy marking
  • Update Model Id (Discovery Metadata) to be more like MSC-DMS
The experimental version of the BOM Schema and an XSLT to transform 2006 based BOMs to the new experimental 2010 version is available here for download.   We encourage you to download these resources and provide feedback to the PSG. Also, the community version of the ConceptualWorks tool, which supports the new and old schema will be available for download soon!

Base Object Model (BOM) Introduction

The Simulation Interoperability Standards Organization (SISO) focuses on facilitating simulation interoperability across government and non-government applications worldwide. One of SISO's interests is to explore methods that support and promote reuse of simulation components and encourage agile, rapid, and efficient development and maintenance of models.

Base Object Models (BOMs) provide a key mechanism in facilitating interoperability, reuse, and composability. BOMs are specifically identified in the IEEE 1516.3 HLA Federation Development and Execution Process (FEDEP) as a potential facilitator for providing reusable model components used for the rapid construction and modification of federates and federations. The open standardization of BOM representations is considered essential for encouraging their development, distribution and use.

The BOM concept is based on the assumption that piece-parts of simulations and federations can be extracted and reused as modeling building-blocks or components. The interplay within a simulation or federation can be captured and characterized in the form of reusable patterns. These patterns of simulation interplay are sequences of events between simulation elements. The implementation of the pattern using HLA object model constructs is also captured in the BOM.

There are two BOM related documents that have been standardized by the SISO via its BOM Product Development Group (PDG). These documents are:

  1. The BOM Template Specification 
  2. The Guide for BOM Use and Implementation.
Also available are answers to your Frequently Asked Questions (FAQ) !

BOM Rationale
M&S continues to provide a proven utility for testing, training and scientific analysis. Its application is expanding in many arenas and disciplines including military and homeland defense, education, manufacturing, medical, logistics, aviation, environmental science and more. SISO seeks to promote interoperability and reuse within the M&S community, and explore ways to enable composability for these arenas and disciplines. BOMs serve to address the operational and technical needs in these areas, especially in regards to composabilty.

Typically, the development and deployment of simulations and mission space environments requires a significant amount of time, effort and collaboration. This might be permissible if it was an occasional thing, but it is not. From a DoD context, simulation is an important aspect of training, testing, mission rehearsal, and prototyping. It has become pervasive, and it is not isolated to just the Navy, or the Army, or the Air Force. Today a distributed simulation exercise may often be at a joint level, where combined assets have been assembled with the intent to model and test them in a large mission space environment.

Some current technology enablers include the following:

  • Interoperability standards such as the HLA and the Run-time Infrastructure (RTI) to connect systems and allow them to exchange meaningful data
  • Process standards such as the FEDEP which help provide guidance and ensure our objectives are being met
  • Various tools and APIs that make the job easier for engineers and developers to build and test federates within a distributed simulation environment.

Despite these enablers, one of the things that still encumbers the M&S community at large is that the task in building and putting together simulation and simulation environments, which must conform to common agreed upon message interfaces, remains an arduous task. That is, it takes a long time, a great deal of effort, and a lot of collaboration. What is required is a composability infrastructure that encourages the development and reuse, across the entire community, of components that are matched to the needs of the desired simulation or simulation space. The BOM standard is seen as a key enabler for supporting composability.

Effect of BOMs
The BOM framework as documented in the BOM specification and the BOM guidance document is intended to influence the following seven capabilities within the M&S community:

  1. Interoperability - The application of Extensible Markup Language (XML) and XML Schemas prescribed for BOMs provides a mechanism for defining and validating context, and facilitates understanding of the data being exchanged. Furthermore, the flexibility offered by BOMs allows for greater application of simulation interoperability within other domains.
  2. Reusability - The meta-data cataloged within a BOM such as intent-of-use, integration history, behavioral information, and potential visual information will facilitate greater reuse of components.
  3. Composability - BOMs will facilitate the ability to rapidly compose simulations and simulation environments both statically (design time) and dynamically (at run-time).
  4. Adaptability - Mega-BOMs produced by BOM compositions can be used to represent the standard data exchange interface for systems and simulations. For instance, HLA compliant federates can continue to use their specific Mega-BOM interface to experiment within environments comprised of other simulations and systems represented by their own unique Mega-BOM interface. Adaptability is accomplished by deploying and applying the appropriate XML-based transformations that represent mappings between common BOMs within a Mega-BOM, by the receiving federate.
  5. Aggregation - The application of BOMs can be used for supporting two types of aggregation: Pattern Aggregation and Entity Aggregation. Pattern Aggregations reflect the coupling of interface groupings that can be identified prior to an exercise. For instance, a Mega-BOM of an automobile can be formulated reflecting the sum of its parts, which might include BOMs such as an Engine, Wheels, Car Body, Braking System and Suspension. Entity Aggregations reflect the coupling of multiple entities into a single inclusive group, which can be accomplished during a federation execution (FEDEX). Essentially, a Mega-BOM would be used to represent a composite interface of a common group of federate objects. For instance, a Mega-BOM representing a battalion might be established to represent an isolated group of troops and their associated vehicles and equipment. The benefit of aggregation is that it can reduce the amount of traffic distributed over the exercise network.
  6. Multi-resolution Models - At the Federate Capability Level, BOMs can be used to represent the behavior states needed for modeling a conceptual entity of one or more patterns of interplay. Federates can choose from an assortment of BOM Component implementations (BCIs) that best represents their needs and system capabilities, even though the interface assembly (i.e. Mega-BOM) that is applied and used by all players may be equivalent. BOM component implementations of varying resolutions can even be swapped out dynamically during an exercise, assuming the proper precautions are taken to ensure validity and consistency. This provides the benefit of federate CPU load reduction and federation optimization.
  7. Rapid Application Development (RAD) Tools and Web Services - It is envisioned that the next generation of tools and web services (such as collaborative development environments and repositories) will emerge to support the creation, deployment and use of BOMs for simulation development, maintenance, and run-time support. The PDG established to develop the BOM standard has sought to identify the explicit high-level tool requirements needed to support BOM creation, deployment and use through the BOM Specification.
  8. Service Oriented Architectures (SOA) - The trend to move from system specific functionality to service oriented architectures is likely to have an enormous influence on distributed simulation. Computer grids are using services to compose them to deliver the currently needed functionality by grid users. BOMs can be used to migrate from existing system centric solutions to SOA capable M&S services.

Market Opportunities
The flexibility offered by an open BOM specification coupled with the RAD type capability it offers, lends itself to a myriad of domains and markets starving for this type of composability. This includes Education and Distance Learning, Medical and Biotechnology, Manufacturing and Processing, Game Development and Entertainment, Environmental and Space Sciences, Logistics and Humanitarian Efforts, and much more. Simulation provides a cost effective tool for all these industries, and BOMs provide an efficient mechanism for enabling such simulation. Some anticipated applications of BOMs that should be considered include:

  • Virtual Hands-on Learning
  • Enabling C4ISR and M&S Interoperability,
  • Supporting Web-based Simulations (such as XMSF profiles),
  • Maintaining HLA Compatibility,
  • Using it for Rapid Prototyping, and
  • Leveraging it (and it's meta-data) for Enabling the Semantic Web.

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