Function (glossary)

From SEBoK
Jump to: navigation, search
(1) A system outcomes which contribute to goals or objectives. To have a function, a system must be able to provide the outcome through two or more different combinations of elemental behavior. (Ackoff 1971)
(2) An action, a task, or an activity performed to achieve a desired outcome. (Hitchins 2007)
(3) A broad work area encompassing multiple related disciplines (e.g., Engineering, Finance, Human Resources, etc.). (Created for SEBoK)
(4) A function is defined by the transformation of input flows to output flows, with defined performance. (Created for SEBoK)


(1) Ackoff, R.L. 1971. "Towards a System of Systems Concepts". Management Science. 17(11).

(2) Hitchins, D. 2007. Systems Engineering: A 21st Century Systems Methodology. Hoboken, NJ, USA: John Wiley & Sons.

(3) and (4) These definitions were developed for the SEBoK.


(1) is the system science definition. All systems have behavior, but to be able to function in a certain way they must have a certain richness of behavior. For example, fight, flight or hide are behaviors; while response to external threats is a function.

(2) is the more traditional Systems Engineering definition, in which functions are identified top down based on needs and then decomposed and allocated to lower level system.

(3) is a HW/SW or human system component definition, describing a function which can be performed by a single part of the system with identified performance.

(4) is a management definiton, describing how similar functions are collected in organizational units.

SEBoK v. 1.6 released 25 March 2016

SEBoK Discussion

Please provide your comments and feedback on the SEBoK below. You will need to log in to DISQUS using an existing account (e.g. Yahoo, Google, Facebook, Twitter, etc.) or create a DISQUS account. Simply type your comment in the text field below and DISQUS will guide you through the login or registration steps. Feedback will be archived and used for future updates to the SEBoK. If you provided a comment that is no longer listed, that comment has been adjudicated. You can view adjudication for comments submitted prior to SEBoK v. 1.0 at SEBoK Review and Adjudication. Later comments are addressed and changes are summarized in the Letter from the Editor and Acknowledgements and Release History.

If you would like to provide edits on this article, recommend new content, or make comments on the SEBoK as a whole, please see the SEBoK Sandbox.

blog comments powered by Disqus