Vee (V) Model (glossary)
The technical aspect of the project cycle is envisioned as a "Vee", starting with User needs on the upper left and ending with a User-validated system on the upper right. (Forsberg and Mooz 1991)
Mooz, H. and K. Forsberg. 1991. "The Relationship of Systems Engineering to the Project Cycle", Joint Conference of INCOSE and the American Society for Engineering Management, 21-23 October 1991, Chattanooga, TN. Available at: https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2334-5837.1991.tb01484.x. Accessed September 11, 2012.