In
systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
,
software engineering
Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principl ...
, and
computer science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...
, a function model or functional model is a structured representation of the
functions (
activities,
actions,
process
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:
Business and management
* Business process, activities that produce a specific s ...
es,
operations) within the modeled
system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
or subject area.
[FIPS Publication 183](_blank)
released of IDEFØ December 1993 by the Computer Systems Laboratory of the National Institute of Standards and Technology (NIST). 
A function model, similar with the
activity model or
process model
The term process model is used in various contexts. For example, in business process modeling the enterprise process model is often referred to as the ''business process model''.
Overview
Process models are processes of the same nature that ...
, is a graphical representation of an
enterprise
Enterprise (or the archaic spelling Enterprize) may refer to:
Business and economics
Brands and enterprises
* Enterprise GP Holdings, an energy holding company
* Enterprise plc, a UK civil engineering and maintenance company
* Enterpris ...
's function within a defined scope. The purposes of the function model are to describe the functions and processes, assist with discovery of information needs, help identify opportunities, and establish a basis for determining product and service costs.
[Reader's Guide to IDEF0 Function Models](_blank)
Accessed 27 Nov 2008.
History
The function model in the field of systems engineering and software engineering originates in the 1950s and 1960s, but the origin of functional modelling of organizational activity goes back to the late 19th century.
In the late 19th century the first diagrams appeared that pictured business activities, actions, processes, or operations, and in the first half of the 20th century the first structured methods for documenting business process activities emerged. One of those methods was the
flow process chart
The flow process chart is a graphical and symbolic representation of the activities performed on the work piece during the operation in industrial engineering.
History
The first structured method for documenting process flow, e.g., in flow sh ...
, introduced by
Frank Gilbreth to members of
American Society of Mechanical Engineers
The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing edu ...
(ASME) in 1921 with the presentation, entitled “Process Charts—First Steps in Finding the One Best Way”.
[Ben B. Graham (2002). ''Detail Process Charting''. p.2.] Gilbreth's tools quickly found their way into
industrial engineering
Industrial engineering (IE) is concerned with the design, improvement and installation of integrated systems of people, materials, information, equipment and energy. It draws upon specialized knowledge and skill in the mathematical, physical, an ...
curricula.
The emergence of the field of ''systems engineering'' can be traced back to
Bell Telephone Laboratories
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the compa ...
in the 1940s. The need to identify and manipulate the properties of a system as a whole, which in complex engineering projects may greatly differ from the sum of the parts' properties, motivated various industries to apply the discipline. One of the first to define the function model in this field was the British engineer
William Gosling. In his book ''The design of engineering systems'' (1962, p. 25) he stated:
:''A functional model must thus achieve two aims in order to be of use. It must furnish a throughput description mechanics capable of completely defining the first and last throughput states, and perhaps some of the intervening states. It must also offer some means by which any input, correctly described in terms of this mechanics, can be used to generate an output which is an equally correct description of the output which the actual system would have given for the input concerned. It may also be noted that there are two other things which a functional model may do, but which are not necessary to all functional models. Thus such a system may, but need not, describe the system throughputs other than at the input and output, and it may also contain a description of the operation which each element carries out on the throughput, but once again this is not.''
One of the first well defined function models, was the
functional flow block diagram (FFBD) developed by the defense-related
TRW Incorporated in the 1950s. In the 1960s it was exploited by the
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
to visualize the time sequence of events in a space systems and flight missions. It is further widely used in classical
systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
to show the order of execution of system functions.
[Thomas Dufresne & James Martin (2003)]
"Process Modeling for E-Business"
. INFS 770 Methods for Information Systems Engineering: Knowledge Management and E-Business. Spring 2003
Functional modeling topics
Functional perspective
In
systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
and
software engineering
Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principl ...
a function model is created with a functional
modeling perspective. The functional perspective is one of the perspectives possible in
business process modelling
Business process modeling (BPM) is the action of capturing and representing processes of an enterprise (i.e. modeling them), so that the current business processes may be analyzed, applied securely and consistently, improved, and automated.
BP ...
, other perspectives are for example behavioural, organisational or informational.
A functional modeling perspective concentrates on describing the
dynamic process. The main concept in this modeling perspective is the process, this could be a function, transformation, activity, action, task etc. A well-known example of a modeling language employing this perspective is
data flow diagram
A data-flow diagram is a way of representing a flow of data through a process or a system (usually an information system). The DFD also provides information about the outputs and inputs of each entity and the process itself. A data-flow diagram ha ...
s.
The perspective uses four symbols to describe a process, these being:
*Process: Illustrates transformation from input to output.
*Store: Data-collection or some sort of material.
*Flow: Movement of data or material in the process.
*External Entity: External to the modeled system, but interacts with it.
Now, with these symbols, a process can be represented as a network of these symbols. This decomposed process is a DFD, data flow diagram.

In
Dynamic Enterprise Modeling a division is made in the
Control model, Function Model,
Process model
The term process model is used in various contexts. For example, in business process modeling the enterprise process model is often referred to as the ''business process model''.
Overview
Process models are processes of the same nature that ...
and
Organizational model.
Functional decomposition
Functional decomposition
In engineering, functional decomposition is the process of resolving a functional relationship into its constituent parts in such a way that the original function can be reconstructed (i.e., recomposed) from those parts.
This process of decompo ...
refers broadly to the process of resolving a
functional relationship into its constituent parts in such a way that the original function can be reconstructed from those parts by
function composition
In mathematics, the composition operator \circ takes two function (mathematics), functions, f and g, and returns a new function h(x) := (g \circ f) (x) = g(f(x)). Thus, the function is function application, applied after applying to . (g \c ...
. In general, this process of decomposition is undertaken either for the purpose of gaining insight into the identity of the constituent components, or for the purpose of obtaining a compressed representation of the global function, a task which is feasible only when the constituent processes possess a certain level of ''modularity''.
Functional decomposition
In engineering, functional decomposition is the process of resolving a functional relationship into its constituent parts in such a way that the original function can be reconstructed (i.e., recomposed) from those parts.
This process of decompo ...
has a prominent role in
computer programming
Computer programming or coding is the composition of sequences of instructions, called computer program, programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of proc ...
, where a major goal is to ''modularize'' processes to the greatest extent possible. For example, a library management system may be broken up into an inventory module, a patron information module, and a fee assessment module. In the early decades of computer programming, this was manifested as the "art of subroutining," as it was called by some prominent practitioners.
Functional decomposition of engineering systems is a method for analyzing engineered systems. The basic idea is to try to divide a system in such a way that each block of the block diagram can be described without an "and" or "or" in the description.
This exercise forces each part of the system to have a pure
function. When a system is composed of pure functions, they can be reused, or replaced. A usual side effect is that the interfaces between blocks become simple and generic. Since the interfaces usually become simple, it is easier to replace a pure function with a related, similar function.
Functional modeling methods
The functional approach is extended in multiple diagrammic techniques and modeling notations. This section gives an overview of the important techniques in chronological order.
Function block diagram
A
functional block diagram is a
block diagram
A block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks. , that describes the functions and interrelationships of a
system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
. The functional block diagram can picture:
* Functions of a system pictured by blocks
* Input of a block pictured with lines, and
* Relationships between 9 functions
* Functional sequences and paths for matter and or signals
The block diagram can use additional schematic symbols to show particular properties.
Specific function block diagram are the classic
functional flow block diagram, and the
Function Block Diagram
The function block diagram (FBD) is a graphical language for programmable logic controller design, that can describe the function between input variables and output variables. A function is described as a set of elementary blocks. Input and o ...
(FBD) used in the design of
programmable logic controller
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that ...
s.
Functional flow block diagram

The
functional flow block diagram (FFBD) is a multi-tier, time-sequenced, step-by-step
flow diagram of the
system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
's functional flow.
[The first version of this article is completely based on th]
NAS SYSTEM ENGINEERING MANUAL SECTION
4.4 VERSION 3.1 06/06/06.
The diagram is developed in the 1950s and widely used in classical
systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
. The functional flow block diagram is also referred to as ''Functional Flow Diagram'', ''functional block diagram'', and ''functional flow''.
[Task Analysis Tools Used Throughout Development](_blank)
FAA 2008. Retrieved 25 Sept 2008.
Functional flow block diagrams (FFBD) usually define the detailed, step-by-step operational and support sequences for
system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
s, but they are also used effectively to define
process
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:
Business and management
* Business process, activities that produce a specific s ...
es in developing and producing systems. The
software development process
In software engineering, a software development process or software development life cycle (SDLC) is a process of planning and managing software development. It typically involves dividing software development work into smaller, parallel, or s ...
es also use FFBDs extensively. In the system context, the functional flow steps may include combinations of
hardware,
software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital comput ...
,
personnel
Employment is a relationship between two parties regulating the provision of paid labour services. Usually based on a contract, one party, the employer, which might be a corporation, a not-for-profit organization, a co-operative, or any othe ...
, facilities, and/or procedures.
In the FFBD method, the functions are organized and depicted by their logical order of execution. Each function is shown with respect to its logical relationship to the execution and completion of other functions. A node labeled with the function name depicts each function. Arrows from left to right show the order of execution of the functions. Logic symbols represent sequential or parallel execution of functions.
[FAA (2006)]
NAS SYSTEM ENGINEERING MANUAL SECTION
4.4 VERSION 3.1 06/06/06.
HIPO and oPO
HIPO for ''hierarchical input process output'' is a popular 1970s
systems analysis
Systems analysis is "the process of studying a procedure or business to identify its goal and purposes and create systems and procedures that will efficiently achieve them". Another view sees systems analysis as a problem-solving technique that ...
design aid and documentation technique for representing the modules of a
system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
as a
hierarchy
A hierarchy (from Ancient Greek, Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy ...
and for documenting each module.
[Sandia National Laboratories (1992)]
Sandia Software Guidelines Volume 5 Tools, Techniques, and Methodologies
SANDIA REPORTS 85–2348qUC–32
It was used to develop requirements, construct the design, and support implementation of an expert system to demonstrate automated rendezvous. Verification was then conducted systematically because of the method of design and implementation.
The overall design of the system is documented using HIPO charts or
structure charts. The structure chart is similar in appearance to an organizational chart, but has been modified to show additional detail. Structure charts can be used to display several types of information, but are used most commonly to diagram either
data structure
In computer science, a data structure is a data organization and storage format that is usually chosen for Efficiency, efficient Data access, access to data. More precisely, a data structure is a collection of data values, the relationships amo ...
s or code structures.
[
]
N2 Chart
The N2 Chart is a diagram in the shape of a matrix
Matrix (: matrices or matrixes) or MATRIX may refer to:
Science and mathematics
* Matrix (mathematics), a rectangular array of numbers, symbols or expressions
* Matrix (logic), part of a formula in prenex normal form
* Matrix (biology), the m ...
, representing functional or physical interfaces between system elements. It is used to systematically identify, define, tabulate, design, and analyze functional and physical interfaces. It applies to system interfaces and hardware and/or software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital comput ...
interfaces.[
The N2 diagram has been used extensively to develop data interfaces, primarily in the ]software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital comput ...
areas. However, it can also be used to develop hardware interfaces. The basic N2 chart is shown in Figure 2. The system functions are placed on the diagonal; the remainder of the squares in the N × N matrix represent the interface inputs and outputs.
[NASA (1995). "Techniques of Functional Analysis". In: ]
NASA Systems Engineering Handbook
'' June 1995. p.142.
Structured Analysis and Design Technique
Structured Analysis and Design Technique (SADT) is a software engineering methodology
Software consists of computer programs that instruct the execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital computers in the mid-20th cen ...
for describing system
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...
s as a hierarchy of functions, a diagram
A diagram is a symbolic Depiction, representation of information using Visualization (graphics), visualization techniques. Diagrams have been used since prehistoric times on Cave painting, walls of caves, but became more prevalent during the Age o ...
matic notation for constructing a sketch for a software application. It offers building blocks to represent entities and activities, and a variety of arrows to relate boxes. These boxes and arrows have an associated informal semantics
Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...
.John Mylopoulos
John Mylopoulos (born 12 July 1943) is a Greek-Canadian computer scientist, Professor at the University of Toronto, Canada, and at the University of Trento, Italy. He is known for his work in the field of conceptual modeling, specifically the de ...
(2004)
Conceptual Modelling III. Structured Analysis and Design Technique (SADT)
Retrieved 21 Sep 2008. SADT can be used as a functional analysis tool of a given process, using successive levels of details. The SADT method allows to define user needs for IT developments, which is used in industrial Information Systems, but also to explain and to present an activity's manufacturing processes, procedures.
at Free-logistics.com. Retrieved 21 Sep 2008.
The SADT supplies a specific functional view of any enterprise by describing the functions and their relationships in a company. These functions fulfill the objectives of a company, such as sales, order planning, product design, part manufacturing, and human resource management. The SADT can depict simple functional relationships and can reflect data and control flow relationships between different functions. The IDEF0 formalism is based on SADT, developed by Douglas T. Ross in 1985.
IDEF0
IDEF0 is a function modeling methodology for describing manufacturing
Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of the
secondary sector of the economy. The term may refer ...
functions, which offers a functional modeling language
A modeling language is any artificial language that can be used to express data, information or knowledge or systems in a structure that is defined by a consistent set of rules. The rules are used for interpretation of the meaning of components in ...
for the analysis, development, re-engineering, and integration of information system
An information system (IS) is a formal, sociotechnical, organizational system designed to collect, process, Information Processing and Management, store, and information distribution, distribute information. From a sociotechnical perspective, info ...
s; business processes; or software engineering analysis.[''Systems Engineering Fundamentals.''](_blank)
Defense Acquisition University Press, 1999. It is part of the IDEF family of modeling languages in the field of software engineering
Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining Application software, software applications. It involves applying engineering design process, engineering principl ...
, and is built on the functional modeling language building SADT.
The IDEF0 Functional Modeling method is designed to model the decisions, actions, and activities of an organization or system.[ 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
In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituenc ...
and semantics
Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...
) and a description of a comprehensive methodology for developing models.[ 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.][ Varun Grover, William J. Kettinger (2000). ''Process Think: Winning Perspectives for Business Change in the Information Age. p.168.]
Axiomatic design
Axiomatic design is a top down hierarchical functional decomposition process used as a solution synthesis framework for the analysis, development, re-engineering, and integration of products, information systems, business processes or software engineering solutions.[Suh (1999). Axiomatic Design: Advances and Applications, Oxford University Press, 2001, ] Its structure is suited mathematically to analyze coupling between functions in order to optimize the architectural robustness of potential functional solution models.
Related types of models
In the field of systems and software engineering numerous specific function and functional models and close related models have been defined. Here only a few general types will be explained.
Business function model
A ''Business Function Model'' (BFM) is a general description or category of operations performed routinely to carry out an organization's mission. They "provide a conceptual structure for the identification of general business functions". It can show the critical business process
A business process, business method, or business function is a collection of related, structured activities or tasks performed by people or equipment in which a specific sequence produces a service or product (that serves a particular business g ...
es in the context of the business area functions. The processes in the business function model must be consistent with the processes in the value chain models. Processes are a group of related business activities performed to produce an end product or to provide a service. Unlike business functions that are performed on a continual basis, processes are characterized by the fact that they have a specific beginning and an end point marked by the delivery of a desired output. The figure on the right depicts the relationship between the business processes, business functions, and the business area's business reference model.
Business Process Model and Notation
Business Process Model and Notation (BPMN) is a graphical representation for specifying business process
A business process, business method, or business function is a collection of related, structured activities or tasks performed by people or equipment in which a specific sequence produces a service or product (that serves a particular business g ...
es in a workflow
Workflow is a generic term for orchestrated and repeatable patterns of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a seque ...
. BPMN was developed by Business Process Management Initiative (BPMI), and is currently maintained by the Object Management Group
The Object Management Group (OMG®) is a computer industry Standards Development Organization (SDO), or Voluntary Consensus Standards Body (VCSB). OMG develops enterprise integration and modeling standards for a range of technologies.
Busin ...
since the two organizations merged in 2005. The current version of BPMN is 2.0.
The Business Process Model and Notation (BPMN) specification provides a graphical notation for specifying business process
A business process, business method, or business function is a collection of related, structured activities or tasks performed by people or equipment in which a specific sequence produces a service or product (that serves a particular business g ...
es in a Business Process Diagram (BPD). The objective of BPMN is to support business process management for both technical users and business users by providing a notation that is intuitive to business users yet able to represent complex process semantics. The BPMN specification also provides a mapping between the graphics of the notation to the underlying constructs of execution languages, particularly BPEL4WS.
Business reference model
A Business reference model is a reference model, concentrating on the functional and organizational aspects of the core business of an enterprise
Enterprise (or the archaic spelling Enterprize) may refer to:
Business and economics
Brands and enterprises
* Enterprise GP Holdings, an energy holding company
* Enterprise plc, a UK civil engineering and maintenance company
* Enterpris ...
, service organization or government agency
A government agency or state agency, sometimes an appointed commission, is a permanent or semi-permanent organization in the machinery of government (bureaucracy) that is responsible for the oversight and administration of specific functions, s ...
. In enterprise engineering a business reference model is part of an Enterprise Architecture Framework or ''Architecture Framework'', which defines how to organize the structure and views associated with an Enterprise Architecture
Enterprise architecture (EA) is a business function concerned with the structures and behaviours of a business, especially business roles and processes that create and use business data. The international definition according to the Federation of ...
.
A reference model A reference model—in systems engineering, systems, enterprise engineering, enterprise, and software engineering—is an abstract framework or domain-specific ontology (information science), ontology consisting of an interlinked set of clearly defi ...
in general is a model of something that embodies the basic goal or idea of something and can then be looked at as a reference for various purposes. A business reference model is a means to describe the business operations of an organization, independent of the organizational structure
An organizational structure defines how activities such as task allocation, coordination, and supervision are directed toward the achievement of organizational aims.
Organizational structure affects organizational action and provides the found ...
that perform them. Other types of business reference model can also depict the relationship between the business process
A business process, business method, or business function is a collection of related, structured activities or tasks performed by people or equipment in which a specific sequence produces a service or product (that serves a particular business g ...
es, business functions, and the business area's business reference model. These reference model can be constructed in layers, and offer a foundation for the analysis of service components, technology, data, and performance.
Operator function model
The ''Operator Function Model'' (OFM) is proposed as an alternative to traditional task analysis
Task analysis is a fundamental tool of human factors engineering. It entails analyzing how a task is accomplished, including a detailed description of both manual and mental activities, task and element durations, task frequency, task allocation, ...
techniques used by human factors
Ergonomics, also known as human factors or human factors engineering (HFE), is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Primary goals of human factors eng ...
engineers. An operator function model attempts to represent in mathematical form how an operator might decompose a complex system into simpler parts and coordinate control actions and system configurations so that acceptable overall system performance is achieved. The model represents basic issues of knowledge representation, information flow, and decision making in complex systems. Miller (1985) suggests that the network structure can be thought of as a possible representation of an operator's internal model of the system plus a control structure which specifies how the model is used to solve the decision problems that comprise operator control functions.Operator Function Model (OFM)
. Accessed 27 Nov 2008.
See also
* Bus Functional Model
* Business process modeling
Business process modeling (BPM) is the action of capturing and representing business processes, processes of an enterprise (i.e. modeling them), so that the current business processes may be analyzed, applied securely and consistently, improved, ...
* Data and information visualization
Data and information visualization (data viz/vis or info viz/vis) is the practice of designing and creating graphic or visual representations of a large amount of complex quantitative and qualitative data and information with the help of stat ...
* Data model
A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. For instance, a data model may specify that the data element representing a car be ...
* Enterprise modeling
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.
It deals with the process of underst ...
* Functional Software Architecture
* Multilevel Flow Modeling
* Polynomial function model
* Rational function model
* Scientific modeling
Scientific modelling is an activity that produces models representing empirical objects, phenomena, and physical processes, to make a particular part or feature of the world easier to understand, define, quantify, visualize, or simulate. It ...
* Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose visual modeling language that is intended to provide a standard way to visualize the design of a system.
UML provides a standard notation for many types of diagrams which can be roughly ...
* View model
Acornsoft was the software arm of Acorn Computers, and a major publisher of software for the BBC Micro and Acorn Electron. As well as games, it also produced a large number of educational titles, extra computer languages and business and ut ...
References
{{DEFAULTSORT:Function Model
Software architecture
Systems analysis
Systems engineering
Software design
Modeling languages
Management cybernetics