Since the "e" sound is at the end of the word, I think both "oo-kay" ou "oo-keh." are correct. It's from the verb "ukeru" meaning "to receive" and it's a term in martial arts for the person who receives an attack. Makes sense, huh? Seme is pronounced either "seh-meh" ou "seh-may" and is from the verb "semeru" meaning "to attack, to assault." And it's the person it martial arts who is attacking.