Computer engineering was a branch of engineering that dealt with the development of computer hardware and software through the combined fields of computer science and electronics.
Rok-Tahk taught herself computer engineering during the time she had alone during the USS Protostar's encounter with a time anomaly in 2383. With that knowledge, Rok was able to discover that, though deleted by Dred 2, Hologram Janeway's memory buffers were never overwritten, so she was able to rebuild her holoprogram. (PRO: "Time Amok")