Korean Romanization 'Sangdoo' / 'Sang-du' rendered character-by-character:
尚 (Sang) +
斗 (Doo). Best known from the romance series
尚斗,我们去上学吧 (Sangdoo, Let's Go to School).
斗 is read dòu here for names - not the dǒu reading used for the dipper/measure.