DATE REVISED: 22 AUGUST 1996
SECTION 4 INFORMATION MODELING AND INFORMATION STANDARDS
This section identifies the minimum standards applicable to information modeling and exchange of information for all DoD programs. Information standards pertain to activity models, data models, data definitions, and information exchanges among systems.
This section provides a set of standards affecting the definition, design, development, and testing of information models and information exchange among systems. It is applicable at all organizational levels and environments, including tactical, strategic, and interfaces to weapons systems. This section addresses information modeling and information standards. Information modeling mandates apply to all systems or components of systems. Information standards mandates apply to all information systems which must interact with any external system or device.
The relationship of Information Models to the DoD Technical Reference Models (TRM) is illustrated in Figure 4-1 . Activity models identify functionality required of mission area applications and identify the types of information required in the data model to support the mission area function. The information requirements identified in the activity model shall be used as the basis for developing a fully attributed, application-specific data model. The data model identifies the logical information requirements and metadata, which forms a basis for physical database schemata and standard data elements. Once implemented in operational systems, the data will be shared using generic information exchange standards.
An information model is a representation at one or more levels of abstraction of a set of real-world processes, products, and/or interfaces. Within the Information System (IS) domain, there are three basic types of models frequently created: activity, data, and interface. Activity models are representations of mission area applications, composed of one or more related activities. Information required to support the mission area function is the primary product of each activity model. A data model, developed from the information requirements documented in the activity model, define entities and their data elements and illustrate the interrelationships among the entities. Interface models tie disparate activities/processes together for a combined functionality. Interface models are customized to fit a particular project, hence material developers and system engineers should create and use interface models as necessary. Security standards related to this section are in Section 6.2.4. This section focuses on the use of data and activity models.
Figure 4-1. Relationship of Information Models to the DoD Technical Reference Model
To support the identification of information and information interchange requirements, the DoD has adopted the Federal Information Processing Standards (FIPS) Publication 183, Integration Definition for Function Modeling (IDEF0) and FIPS Publication 184, Integration Definition for Information Modeling (IDEF1X), for activity and data modeling, respectively. The Integrated (Computer-Aided Manufacturing) Definition (IDEF) Modeling methodology defines an unambiguous set of the following components:
a.) Symbols (i.e., syntax) associated with modeling concepts and ideas
b.) Rules for composing these symbols into abstract constructs
c.) Rules for mapping "meanings" (i.e., semantics) to these constructs
d.) Definitions of the relationships between activities and entities.
Information Standards define a logical view of data (meaning and contextual use) within an architecture. The activity model is a view of the activities, both automated and manual, that an organization must perform to achieve its mission. Modeling an organization's processes and data begins at the highest logical level, decomposes into lower logical levels and is communicated in a format that the users, particularly the subject matter experts, can easily understand and use.
In order to provide a single authoritative source for data standards, the DoD created the Defense Data Dictionary System (DDDS). The DDDS, managed by DISA, is a DoD-wide central database that includes standard data entities, data elements, and access to data models. The DDDS is used to collect individual data standards derived from the DoD data model and to document content and format for data elements. The DDDS is the authoritative source for all DoD data standards.
Recent studies show three necessary data characteristics must be known to define interoperable databases. First, the contextual view of data must be developed to understand how data elements interact with each other. Second, the data element definitions must be unambiguous. Third, the foreign key identifiers must be defined in parent-to-child data relationships. These characteristics are contained within the combination of the DDDS, IDEF0, and IDEF1X models. Figure 4-2 provides a logical view of how the activity and data modeling standards contained in this section will support the development of interoperable systems.
Today, Command, Control, Communications, Computers, and Intelligence (C4I) information exchange is accomplished for the most part by sending fixed content formatted messages. The definition and documentation of these exchange mechanisms are provided by various messaging standards. Each message standard provides a means to define message form and functions (i.e., transfer syntax), which includes the definition of the message elements that are contained in each message. The message fields, which are currently defined in the various message standards, are not necessarily mutually consistent, nor are they consistently based on any process or data models either within a message system or across message systems. Newer techniques provide direct database-to-database exchange of data without the user following a rigid format. A model based on structure will eventually provide definitions which will be data elements-based and will be compliant with the defense data element standards established in accordance with the DoD Directive (DoDD) 8320.1, Data Administration, and associated DoD 8320.1 manuals.
C4I is the framework for situational awareness, decision making, and execution throughout the battlespace. Efficient execution of information exchange requirements (IERs) throughout the joint battlespace is key to evolving C4I toward the ultimate goal of seamless information exchange. The primary component of this infrastructure is the C4I Tactical Data Link (TDL), comprised of message elements/messages and physical media. However, due to the diversity of Warfighter requirements, no single data link is applicable to every C4I platform and weapon system.
Tactical Digital Information Links (TADILs), structured on bit-oriented message standards, evolved to meet critical real-time and near-real-time message requirements. The United States Message Text Format (USMTF), designed primarily for non-real-time exchange, is based on a character-oriented message format and is the standard for man-readable and machine-processable information exchange. TDLs, character-oriented/man-readable (USMTF messages), imagery standards, voice, and video will provide a timely, integrated, and coherent picture for joint commanders and their operational forces.
Disparate data link message formats and communications media have resulted in untimely delivery of crucial battlefield information. This causes significant interoperability problems among the Commanders-in-Chief (CINCs), Services, Agencies (C/S/As), and allied nations. Currently, it is difficult to establish seamless information flow among diverse data link units. Future joint operations, such as ballistic missile defense and battlefield digitization, will place greater emphasis on the need for automated C4I functions. Tomorrow's battlefields will vastly increase the burden on C4I networks.
Figure 4-2. Objective Information Standards TA
This subsection identifies the mandatory standards, profiles, and practices for information modeling and information standards. Each mandated standard or practice is clearly identified on a separate line, and includes a formal reference that can be included within Requests for Proposals (RFP) or Statements of Work (SOW). Appendix B contains a table that summarizes the mandated standards from this section, as well as providing information on how to obtain the standards. The World Wide Web (WWW) version of Appendix B contains a link to the standard or to the organization that maintains the standard when one is available.
Activity models are used to document/model the activities, processes, and data flows supporting the requirements of a new system or a major update. Prior to system development, an activity model is prepared to depict the mission area function to a level of detail sufficient to identify each entity in the data model that is involved in an activity. The activity model forms the basis for data model development or refinement. The activity model is validated against the requirements and doctrine, and approved by the operational sponsor.
The mandated standard for activity modeling is:
The DoD Data Model (DDM) is a department-wide data model which provides the standard definition and use of specific data elements to the developers of all DoD systems. Adherence to the DDM will ensure DoD agencies are data interoperable among all information systems. The information requirements of a new or major system shall be documented within a data model. The basis for data modeling shall be DDM.
Tactical systems shall incorporate applicable Command and Control (C2) Core Data Model (C2CDM) requirements. The C2CDM is a subset of the DDM. Both are accessible via File Transfer Protocol (FTP) from the DDDS server. The DDM provides the tactical metadata and modeling elements for all approved, candidate, and developmental DoD data standards managed by the functional data stewards. New information requirements are submitted by requiring Components and Defense Agencies and approved by functional data stewards in accordance with DoD Manual 8320.1-M-1, DoD Data Standardization Procedures and shall be used to extend the DDM and C2CDM, as appropriate. Computer Automated Software Engineering (CASE) tools that support IDEF1X diagrams are used to extend the model with additional logical entities, attributes, and relationships.
The data models shall be used in software requirements analyses and design activities as a logical basis for physical database design. Developers of new and existing systems shall maintain traceability between their physical database schema and the DDM and C2CDM, as applicable, allowing links from interface requirements to database population and update processes. The Intelligence community's Modernized Integrated Database (MIDB) is being harmonized with the C2CDM and migrating to DDM.
The mandated standards for Data Modeling are:
The Defense Data Dictionary System (DDDS) is a central database that includes standard data entities, data elements, and provides access to DDM files from the DDDS server. Procedures governing the use of and access to the DDDS are delineated in DoD Manual 8320.1-M-1. A classified version of the DDDS, known as the Secure Intelligence Data Repository (SIDR), is being developed to support standardization of classified data elements and domains. System developers shall use the DDDS as a primary source of data element standards.
The mandated standards for DoD Data Definitions are:
Information Standards refer to the exchange of information among mission area applications within the same system or among different systems. The scope of information standards. follows:
For purposes of clarification, Information Standards is the system or application-independent ability of data to be shared, whereas Data Interchange is system or application-specific. Hence, this section discusses information standards as the generic ability of a system or application to share data. Interchange standards help form the Common Operating Environment (COE) ensuring the use of system or application formats which can share data. Key references include Section 2.2.2.1.3, for SQL standards in Data Management Services and Section 2.2.2.1.4 for Data Interchange Services.
The message standards below are joint/combined message standards that provide for the formatted transfer of information between systems. Although it must be recognized that the J-Series Family of TDLs and the USMTF Standards are not model-based and therefore do not meet the goals of standard information exchange, they must be recognized as existing standards. As more systems are developed using logical data models and standard data elements, these message standards must evolve to be data model-based if they are to continue to support joint automated systems.
The J-Series Family of TDLs allow information exchange using common data element structures and message formats which support time critical information. They include Air Operations/Defense Maritime, Fire Support, and Maneuver Operations. These are the primary data links for exchange of bit-oriented information. The family consists of LINK 16, LINK 22, and the Variable Message Format (VMF) and interoperability is achieved through use of J-Series family messages and data elements. The policy and management of this family is described in the Joint Tactical Data Link Management Plan (JTDLMP), dated April 1996.
New message requirements shall use these messages and data elements or use the message construction hierarchy described in the JTDLMP. The mandated standards for information exchange are:
USMTF messages are jointly agreed, fixed-format, character-oriented messages that are man-readable and machine-processable. The standard is documented in MIL-STD 6040 and the interface operating procedures are documented in CJCSM 6120.05, Procedures for US Message Text Formats. USMTFs are the mandatory standard for record AUTODIN and in the future, DMS messages when communicating with the Joint Staff, Combatant Commands, and Service Components.
The mandated standard for USMTF Messages is:
The distributed computing services stated in Section 2.2.2.2.4 provide the capability to exchange standard data among heterogeneous platforms.
The following is mandated:
The standards listed in this subsection are expected to be elevated to mandatory status when implementations of the standards mature.
There are no emerging activity models standards.
The emerging standard for data modeling is IDEF1X97, Conceptual Schema Modeling. This standard accommodates object-oriented methods (OOM). IDEF1X97 is being developed by the IEEE IDEF1X Standards Working Group of the IEEE 1320.2 Standards Committee. The standard describes two styles of the IDEF1X model. The key-style is used to produce information models which represent the structure and semantics of data within an enterprise and is backward-compatible with the US Government's Federal Standard for IDEF1X, FIPS 184. The identity-style is a wholly new language which provides system designers and developers a robust set of modeling capabilities covering all static and many dynamic aspects of the emerging object model. This identity-style can, with suitable automation support, be used to develop a model which is an executable prototype of the target object-oriented system. The identity-style can be used in conjunction with emerging dynamic modeling techniques to produce full object-oriented models.
DISA JIEO, in coordination with the Standards Coordinating Committee (SCC) and the Change Control Board (CCB), will develop the strategy/policy for migration from many tactical data link (bit-oriented) and character-oriented joint message standards to a minimal family of DoD 8320.1-compliant information exchange standards. A normalized unified data/message element dictionary will be developed based on normalized Data Model and associated data element standards. The dictionary will support both character and bit-oriented representation of the standard data and their domain values. Message standards will then establish the syntax for standard data packaging to support mission requirements (e.g., character or bit-oriented, fixed or variable format, etc.). The unified data dictionary will ensure that multiple representations are minimized and transformation algorithms are standardized. The Data Model basis for the data elements will ensure the information is normalized. A classified version of the DDDS, known as the SIDR, is being developed to support standardization of classified data elements and domains.
JTIDS will soon be supplemented by the Multi-functional Information Distribution System (MIDS). Message format standards for MIDS will not change from those of the JTIDS. Message and data element standards must be independent of the information transfer standards, protocols, and profiles. Refer to section 3 of this document for information transfer standards.
MIL-STD-6016 will most likely be called DoD Interface Standard, Tactical Digital Information Link (TADIL) J Message Standard, expected to be dated on or about 30 September 1996.
STANAG 5516, Edition 2, is currently under development at JIEO, for delivery to the NATO Data Ling Working Group (DLWG) sometime prior to the 11th meeting in November 1996.
STANAG 5522, Edition 1, Tactical Data Exchange - LINK 22 (Undated) is the Configuration Management (CM) baseline document.
VMF Technical Interface Design Plan - Reissue 2, is currently under development at JIEO, with a planned release date by 30 August 1996.