international student immigration review Korea Korean university visa international student administrative risk Korea student visa Korea international student job rules korea student attendance Korea job seeking visa korea student visa attendance rules Korea international student Korea international student attendance Korea study in Korea D-2 visa Korea hikorea d10 university change immigration Korea D-4 work permission international student visa korea problems student part time work korea visa student visa pattern issues Korea international student visa rejection Korea student visa korea attendance work rules international student korea immigration student visa instability Korea D-2 part-time job part-time work Korea student visa transfer Korea student work permit Korea part-time work Korea international students student visa korea attendance rules d-10 visa korea student visa after graduation student visa korea rules international student korea immigration attendance korea student visa document mistake Korea