It's essentially the v model [1] for software development. It's commonly used in systems engineering and the industries that implement it, so military, avionics, medical, safety engineering etc. I work on industrial safety systems, and would echo the other posts here - it's a requirement of the industry, but it's rarely done well due to the cost to implement, and the difficulty in implementing tools like Doors.

NASA and the U.S. Military have good guides and white papers on it, which you should be able to find online with a bit of digging.

[1] http://en.m.wikipedia.org/wiki/V-Model_(software_development...