A Doctor of Engineering degree awarded by universities in China, Japan, and South Korea is equivalent to a PhD degree. To be admitted as a doctoral student, one must hold a master's degree in the same or related subject and pass a comprehensive entrance exam. The student must complete necessary course work, perform independent research under the supervision of a qualified Doctoral Advisor, and pass the thesis defense. It usually takes more than three years for a student with an M.S. Degree to complete his/her doctoral study. However, there are few areas of study (such as Materials Science, Polymer Technology, and Biomedical Engineering) where both Doctor of Science and Doctor of Engineering can be awarded depending upon the graduate school which houses the department.