Is work experience required for any postgraduate or professional programs at Yonsei?

No, for most of the Yonsei University courses, work experience is not mandatory for most PG programs. 

However, it is often required for courses like MBA. Other than work experience, given below are the admission requirements for students - 

• A strong GPA
• English (IELTS with 6.0+ or TOEFL 91+) or Korea