After graduating the Academy in 2371 Daniel Byrd was assigned to the Yellowstone class development project, where he was key in solving warp plasma flow problems that were plaguing the project. (Star Trek: Prometheus).
In an alternate timeline, Harry Kim was assigned to Yellowstone class development project, following his graduation from the Academy, and was the person in that reality that solved the plasma flow problems. In this timeline's 2372, Harry Kim, along with Tom Paris, stole the prototype. (VOY: "Non Sequitur")