IDEF0

Last updated September 10, 2024

IDEF0, a compound acronym ("Icam DEFinition for Function Modeling", where ICAM is an acronym for "Integrated Computer Aided Manufacturing"), is a function modeling methodology for describing manufacturing functions, which offers a functional modeling language for the analysis, development, reengineering and integration of information systems, business processes or software engineering analysis.^[1]

Overview

The IDEF0 Functional Modeling method is designed to model the decisions, actions, and activities of an organization or system.^[2] It was derived from the established graphic modeling language Structured Analysis and Design Technique (SADT) developed by Douglas T. Ross and SofTech, Inc. In its original form, IDEF0 includes both a definition of a graphical modeling language (syntax and semantics) and a description of a comprehensive methodology for developing models.^[3] The US Air Force commissioned the SADT developers "to develop a function model method for analyzing and communicating the functional perspective of a system. IDEF0 should assist in organizing system analysis and promote effective communication between the analyst and the customer through simplified graphical devices".^[2]

Where the Functional flow block diagram is used to show the functional flow of a product, IDEF0 is used to show data flow, system control, and the functional flow of lifecycle processes. IDEF0 is capable of graphically representing a wide variety of business, manufacturing and other types of enterprise operations to any level of detail. It provides rigorous and precise description, and promotes consistency of usage and interpretation. It is well-tested and proven through many years of use by government and private industry. It can be generated by a variety of computer graphics tools. Numerous commercial products specifically support development and analysis of IDEF0 diagrams and models.^[1]

An associated technique, Integration Definition for Information Modeling (IDEF1x), is used to supplement IDEF0 for data-intensive systems. The IDEF0 standard, Federal Information Processing Standards Publication 183 (FIPS 183), and the IDEF1x standard (FIPS 184) are maintained by the National Institute of Standards and Technology (NIST).^[1]

FIPS PUB 183 "Integration Definition for Function Modeling (IDEF0)," was withdrawn as a Federal Standard (in favor of OPEN Specifications and Standards) September 2, 2008, as cited in "The Federal Register", Volume 73, page 51276 (73FR/51276). ^[4]

History

During the 1970s, the U.S. Air Force Program for Integrated Computer Aided Manufacturing (ICAM) sought to increase manufacturing productivity through systematic application of computer technology. The ICAM program identified the need for better analysis and communication techniques for people involved in improving manufacturing productivity. As a result, in 1981 the ICAM program developed a series of techniques known as the IDEF (ICAM Definition) techniques which included the following:^[3]

IDEF0, used to produce a "function model". A function model is a structured representation of the functions, activities or processes within the modeled system or subject area.^[5]
IDEF1, used to produce an "information model". An information model represents the structure and semantics of information within the modeled system or subject area.^[6]
IDEF2, used to produce a "dynamics model". A dynamics model represents the time-varying behavioral characteristics of the modeled system or subject area.^[7]

In 1983, the U.S. Air Force Integrated Information Support System program enhanced the IDEF1 information modeling technique to form IDEF1X (IDEF1 Extended), a semantic data modeling technique. By the 1990s, IDEF0 and IDEF1X techniques are widely used in the government, industrial and commercial sectors, supporting modeling efforts for a wide range of enterprises and application domains. In 1991 the National Institute of Standards and Technology (NIST) received support from the U.S. Department of Defense, Office of Corporate Information Management (DoD/CIM), to develop one or more Federal Information Processing Standard (FIPS) for modeling techniques. The techniques selected were IDEF0 for function modeling and IDEF1X for information modeling. These FIPS documents are based on the IDEF manuals published by the U.S. Air Force in the early 1980s.^[3] Sometime later, IEEE created the IDEF0 standard, and ISO adopted and published it as IEEE/ISO/IEC 31320-1.

IDEF0 topics

The IDEF0 approach

IDEF0 may be used to model a wide variety of automated and non-automated systems. For new systems, it may be used first to define the requirements and specify the functions, and then to design an implementation that meets the requirements and performs the functions. For existing systems, IDEF0 can be used to analyze the functions the system performs and to record the mechanisms (means) by which these are done. The result of applying IDEF0 to a system is a model that consists of a hierarchical series of diagrams, text, and glossary cross-referenced to each other. The two primary modeling components are functions (represented on a diagram by boxes) and the data and objects that inter-relate those functions (represented by arrows).^[3]

IDEF0 Building blocks

The IDEF0 model displayed here on the left is based on a simple syntax. Each activity is described by a verb-based label placed in a box. Inputs are shown as arrows entering the left side of the activity box while output are shown as exiting arrows on the right side of the box. Controls are displayed as arrows entering the top of the box and mechanisms are displayed as arrows entering from the bottom of the box. Inputs, Controls, Outputs, and Mechanisms (ICOM) are all referred to as concepts.^[2]

Arrow : A directed line, composed of one or more arrow segments, that models an open channel or conduit conveying data or objects from source (no arrowhead) to use (with arrowhead). There are 4 arrow classes: Input Arrow, Output Arrow, Control Arrow, and Mechanism Arrow (includes Call Arrow). See Arrow Segment, Boundary Arrow, Internal Arrow.
Box : A rectangle, containing a name and number, used to represent a function.

Box Syntax
Arrow Syntax
Arrow Positions and Roles
Label and Name Semantics

Context : The immediate environment in which a function (or set of functions on a diagram) operates.
Decomposition : The partitioning of a modeled function into its component functions.

Example Top-level Diagram
Decomposition Structure
Detail Reference Expression Use
Arrow Fork and Join Structures

Fork : The junction at which an IDEF0 arrow segment (going from source to use) divides into two or more arrow segments. May denote unbundling of meaning.

Connections Between Boxes
Boundary and Internal Arrows
Typical Node Tree
Negative Node-Numbered Context

Function : An activity, process, or transformation (modeled by an IDEF0 box) identified by a verb or verb phrase that describes what must be accomplished.
Join : The junction at which an IDEF0 arrow segment (going from source to use) merges with one or more other arrow segments to form a single arrow segment. May denote bundling of arrow segment meanings
Node : A box from which child boxes originate; a parent box. See Node Index, Node Tree, Node Number, Node Reference, Diagram Node Number.

Graphical notation

IDEF0 is a model that consists of a hierarchical series of diagrams, text, and glossary cross referenced to each other. The two primary modeling components are:

functions (represented on a diagram by boxes), and
data and objects that interrelate those functions (represented by arrows).

As shown by Figure 3 the position at which the arrow attaches to a box conveys the specific role of the interface. The controls enter the top of the box. The inputs, the data or objects acted upon by the operation, enter the box from the left. The outputs of the operation leave the right-hand side of the box. Mechanism arrows that provide supporting means for performing the function join (point up to) the bottom of the box.^[1]

The IDEF0 process

The IDEF0 process starts with the identification of the prime function to be decomposed. This function is identified on a “Top Level Context Diagram,” that defines the scope of the particular IDEF0 analysis. An example of a Top Level Context Diagram for an information system management process is shown in Figure 3. From this diagram lower-level diagrams are generated. An example of a derived diagram, called a “child” in IDEF0 terminology, for a life cycle function is shown in Figure 4.^[1]

Federal Information Processing Standards

In Dec 1993 the National Institute of Standards and Technology announcing the standard for Integration Definition for Function Modeling (IDEF0) in the category Software Standard, Modeling Techniques. This publication announces the adoption of the IDEF0 as a Federal Information Processing Standard (FIPS). This standard was based on the Air Force Wright Aeronautical Laboratories Integrated Computer-Aided Manufacturing (ICAM) Architecture from June 1981.^[3]

On September 2, 2008, the associated NIST standard, FIPS 183, has been withdrawn (decision on Federal Register vol. 73 / page 51276.^[4]

Related Research Articles

The Federal Information Processing Standards (FIPS) of the United States are a set of publicly announced standards that the National Institute of Standards and Technology (NIST) has developed for use in computer situs of non-military United States government agencies and contractors. FIPS standards establish requirements for ensuring computer security and interoperability, and are intended for cases in which suitable industry standards do not already exist. AIR FIPS specifications are modified versions of standards the technical communities use, such as the American National Standards Institute (ANSI), the Institute of Electrical and Electronics Engineers (IEEE), and the International Organization for Standardization (ISO).

IDEF, initially an abbreviation of ICAM Definition and renamed in 1999 as Integration Definition, is a family of modeling languages in the field of systems and software engineering. They cover a wide range of uses from functional modeling to data, simulation, object-oriented analysis and design, and knowledge acquisition. These definition languages were developed under funding from U.S. Air Force and, although still most commonly used by them and other military and United States Department of Defense (DoD) agencies, are in the public domain.

The Federal Information Processing Standard Publication 140-2,, is a U.S. government computer security standard used to approve cryptographic modules. The title is Security Requirements for Cryptographic Modules. Initial publication was on May 25, 2001, and was last updated December 3, 2002.

The Initial Graphics Exchange Specification (IGES) is a vendor-neutral file format that allows the digital exchange of information among computer-aided design (CAD) systems. It is an ASCII-based textual format.

<span class="mw-page-title-main">Business process modeling</span> Activity of representing processes of an enterprise

Business process modeling (BPM), mainly used in business process management; software development, or systems engineering, is the action of capturing and representing processes of an enterprise, so that the current business processes may be analyzed, applied securely and consistently, improved, and automated. BPM is typically orchestrated by business analysts, leveraging their expertise in modeling practices. Subject matter experts, equipped with specialized knowledge of the processes being modeled, often collaborate within these teams. Alternatively, process models can be directly derived from digital traces within IT systems, such as event logs, utilizing process mining tools.

Integrated Computer-Aided Manufacturing (ICAM) is a US Air Force program that develops tools, techniques, and processes to support manufacturing integration. It influenced the computer-integrated manufacturing (CIM) and computer-aided manufacturing (CAM) project efforts of many companies. The ICAM program was founded in 1976 and initiative managed by the US Air Force at Wright-Patterson as a part of their technology modernization efforts. The program initiated the development a series of standards for modeling and analysis in management and business improvement, called Integrated Definitions, short IDEFs.

A functional software architecture (FSA) is an architectural model that identifies enterprise functions, interactions and corresponding IT needs. These functions can be used as a reference by different domain experts to develop IT-systems as part of a co-operative information-driven enterprise. In this way, both software engineers and enterprise architects can create an information-driven, integrated organizational environment.

An information model in software engineering is a representation of concepts and the relationships, constraints, rules, and operations to specify data semantics for a chosen domain of discourse. Typically it specifies relations between kinds of things, but may also include relations with individual things. It can provide sharable, stable, and organized structure of information requirements or knowledge for the domain context.

<span class="mw-page-title-main">Structured analysis and design technique</span>

Structured analysis and design technique (SADT) is a systems engineering and software engineering methodology for describing systems as a hierarchy of functions. SADT is a structured analysis modelling language, which uses two types of diagrams: activity models and data models. It was developed in the late 1960s by Douglas T. Ross, and was formalized and published as IDEF0 in 1981.

Integration DEFinition for information modeling (IDEF1X) is a data modeling language for the development of semantic data models. IDEF1X is used to produce a graphical information model which represents the structure and semantics of information within an environment or system.

Enterprise modelling is the abstract representation, description and definition of the structure, processes, information and resources of an identifiable business, government body, or other large organization.

In software engineering, structured analysis (SA) and structured design (SD) are methods for analyzing business requirements and developing specifications for converting practices into computer programs, hardware configurations, and related manual procedures.

Douglas Taylor "Doug" Ross was an American computer scientist pioneer, and chairman of SofTech, Inc. He is most famous for originating the term CAD for computer-aided design, and is considered to be the father of Automatically Programmed Tools (APT), a programming language to drive numerical control in manufacturing. His later work focused on a pseudophilosophy he developed and named Plex.

In systems engineering, software engineering, and computer science, a function model or functional model is a structured representation of the functions within the modeled system or subject area.

A functional flow block diagram (FFBD) is a multi-tier, time-sequenced, step-by-step flow diagram of a system's functional flow. The term "functional" in this context is different from its use in functional programming or in mathematics, where pairing "functional" with "flow" would be ambiguous. Here, "functional flow" pertains to the sequencing of operations, with "flow" arrows expressing dependence on the success of prior operations. FFBDs may also express input and output data dependencies between functional blocks, as shown in figures below, but FFBDs primarily focus on sequencing.

A semantic data model (SDM) is a high-level semantics-based database description and structuring formalism for databases. This database model is designed to capture more of the meaning of an application environment than is possible with contemporary database models. An SDM specification describes a database in terms of the kinds of entities that exist in the application environment, the classifications and groupings of those entities, and the structural interconnections among them. SDM provides a collection of high-level modeling primitives to capture the semantics of an application environment. By accommodating derived information in a database structural specification, SDM allows the same information to be viewed in several ways; this makes it possible to directly accommodate the variety of needs and processing requirements typically present in database applications. The design of the present SDM is based on our experience in using a preliminary version of it. SDM is designed to enhance the effectiveness and usability of database systems. An SDM database description can serve as a formal specification and documentation tool for a database; it can provide a basis for supporting a variety of powerful user interface facilities, it can serve as a conceptual database model in the database design process; and, it can be used as the database model for a new kind of database management system.

Enterprise engineering is the body of knowledge, principles, and practices used to design all or part of an enterprise. An enterprise is a complex socio-technical system that comprises people, information, and technology that interact with each other and their environment in support of a common mission. One definition is: "an enterprise life-cycle oriented discipline for the identification, design, and implementation of enterprises and their continuous evolution", supported by enterprise modelling. The discipline examines each aspect of the enterprise, including business processes, information flows, material flows, and organizational structure. Enterprise engineering may focus on the design of the enterprise as a whole, or on the design and integration of certain business components.

A control-flow diagram (CFD) is a diagram to describe the control flow of a business process, process or review.

IDEF3 or Integrated DEFinition for Process Description Capture Method is a business process modelling method complementary to IDEF0. The IDEF3 method is a scenario-driven process flow description capture method intended to capture the knowledge about how a particular system works.

Richard J. Mayer is an American engineer, President of Knowledge Based Systems, Inc., known as lead engineer and principal investigator on the projects of developing part of the IDEF family of modeling languages in the field of software and systems engineering.

References

Systems Engineering Fundamentals. Defense Acquisition University Press, 2001.

This article incorporates public domain material from the National Institute of Standards and Technology

1 2 3 4 5 Systems Engineering Fundamentals. Defense Acquisition University Press, 2001.
1 2 3 Varun Grover, William J. Kettinger (2000). Process Think: Winning Perspectives for Business Change in the Information Age. p.168.
1 2 3 4 5 FIPS Publication 183 Archived 2009-02-27 at the Wayback Machine released of IDEFØ December 1993 by the Computer Systems Laboratory of the National Institute of Standards and Technology (NIST).
1 2 Withdrawn FIPS Listed by Number, Updated 12/15/16)
↑ ICAM Architecture Part II-Volume IV - Function Modeling Manual (IDEF0), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.
↑ ICAM Architecture Part II, Volume V - Information Modeling Manual (IDEF1), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.
↑ ICAM Architecture Part II, Volume VI - Dynamics Modeling Manual (IDEF2), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.

External links

FIPS Publication 183 released of IDEFØ December 1993 by the Computer Systems Laboratory of the National Institute of Standards and Technology (NIST). (Withdrawn by NIST 08 Sep 02 see Withdrawn FIPS by Numerical Order Index)
Federal Register vol. 73 / page 51276 withdrawal decision
Overview of IDEF0 at www.idef.com

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[DAC01-1] 1 2 3 4 5 Systems Engineering Fundamentals. Defense Acquisition University Press, 2001.

[VG00-2] 1 2 3 Varun Grover, William J. Kettinger (2000). Process Think: Winning Perspectives for Business Change in the Information Age. p.168.

[ITL93-3] 1 2 3 4 5 FIPS Publication 183 Archived 2009-02-27 at the Wayback Machine released of IDEFØ December 1993 by the Computer Systems Laboratory of the National Institute of Standards and Technology (NIST).

[fips_withdrawn-4] 1 2 Withdrawn FIPS Listed by Number, Updated 12/15/16)

[5] ICAM Architecture Part II-Volume IV - Function Modeling Manual (IDEF0), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.

[6] ICAM Architecture Part II, Volume V - Information Modeling Manual (IDEF1), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.

[7] ICAM Architecture Part II, Volume VI - Dynamics Modeling Manual (IDEF2), AFWAL-TR-81-4023, Materials Laboratory, Air Force Wright Aeronautical Laboratories, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, June 1981.

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