Editing V-model (section)

== Applications ==
[[Image:VPM3e Vee with detail.gif|thumb|320px|Off-Core alternatives (illustrating upward and downward iterations and Time and Maturity dimension). Source - K. Forsberg and H. Mooz 2004<ref name=VPM/><ref name=Original/>]]
The V-model is used to regulate the software development process within the German federal administration. Nowadays{{when|date=January 2023}} it is still the standard for German federal administration and defense projects, as well as software developers within the region.

The concept of the V-model was developed simultaneously, but independently, in Germany and in the United States in the late 1980s:

* The German V-model was originally developed by IABG in Ottobrunn, near Munich, in cooperation with the Federal Office for Defense Technology and Procurement in Koblenz, for the Federal Ministry of Defense. It was taken over by the Federal Ministry of the Interior for the civilian public authorities domain in summer 1992.<ref name=GermanOriginal>{{cite web|url=http://www.v-modell.iabg.de/kurzb/vm/k_vm_e.doc|title=V-Model Lifecycle Process Model|publisher=v-modell.iabg.de|access-date=December 24, 2015|archive-url=https://web.archive.org/web/20160303204644/http://www.v-modell.iabg.de/kurzb/vm/k_vm_e.doc|archive-date=March 3, 2016|url-status=dead|df=mdy-all}}</ref>
* The US V-model, as documented in the 1991 proceedings for the [[International Council on Systems Engineering|National Council on Systems Engineering]] (NCOSE; now INCOSE as of 1995),<ref name=Original/> was developed for satellite systems involving hardware, software, and human interaction.
* The V-model first appeared at [[Hughes Aircraft]] circa 1982 as part of the pre-proposal effort for the FAA Advanced Automation System (AAS) program. It eventually formed the test strategy for the Hughes AAS Design Competition Phase (DCP) proposal. It was created to show the test and integration approach which was driven by new challenges to surface latent defects in the software. The need for this new level of latent defect detection was driven by the goal to start automating the thinking and planning processes of the air traffic controller as envisioned by the automated enroute air traffic control (AERA) program. The reason the V is so powerful comes from the Hughes culture of coupling all text and analysis to multi dimensional images. It was the foundation of Sequential Thematic Organization of Publications (STOP) <ref name="scribd">{{cite web |url=https://www.scribd.com/doc/2019286/Sequential-Thematic-Organization-of-Publications |archive-url=https://web.archive.org/web/20080203133138/http://www.scribd.com/doc/2019286/Sequential-Thematic-Organization-of-Publications |archive-date=February 3, 2008 |url-status=dead |title=Sequential Thematic Organization of Publications (STOP) |access-date=December 24, 2015 |df=mdy-all }}</ref> created by Hughes in 1963 and used until Hughes was divested by the [[Howard Hughes Medical Institute]] in 1985.<ref>{{cite book | title = Sustainable Development Possible with Creative System Engineering|isbn=978-0615216300|last1=Sobkiw|first1=Walter|date=2008-01-01|publisher=Lulu.com }}</ref>
* The US Department of Defense puts the [[systems engineering]] process interactions into a V-model relationship.<ref>{{cite web 
| url = http://www.dau.mil/pubscats/PubsCats/atl/2006_03_04/mar-apr06.pdf
| title = A New Systems Engineering Model and an Old, Familiar Friend; Figure 2 V-9 Process Interactions
| publisher = Defense AT&L
| page = 51
| date = Apr 2006
| access-date = 7 Apr 2016}}</ref>

It has now found widespread application in commercial as well as defense programs. Its primary use is in project management<ref name=VPM/><ref name=INCOSE/> and throughout the project lifecycle.

One fundamental characteristic of the US V-model is that time and maturity move from left to right and one cannot move back in time. All iteration is along a vertical line to higher or lower levels in the system hierarchy, as shown in the figure.<ref name=VPM/><ref name=INCOSE/><ref name=Original/>  This has proven to be an important aspect of the model. The expansion of the model to a dual-Vee concept is treated in reference.<ref name=VPM/>

As the V-model is publicly available many companies also use it. In project management it is a method comparable to [[PRINCE2]] and describes methods for project management as well as methods for [[Systems development lifecycle|system development]]. The V-model, while rigid in process, can be very flexible in application, especially as it pertains to the scope outside of the realm of the System Development Lifecycle normal parameters.