Brown University’s president announced yesterday she will continue to support the school’s policy of denying full academic privileges to ROTC instructors and cadets, which dates back to the Vietnam War. The university’s board is expected to ratify her decision by Saturday. The move makes the school - which has three cadets who participate in ROTC at another college - a lone holdout in the Ivy League. Its peer universities have thawed toward ROTC this year after decades of frosty relations.