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