That was the message from Robert Work, the undersecretary of the Navy, to the opening of the Office of Naval Research’s annual science and technology conference in Arlington, Virginia, where the Navy and its contractors are showing off some of their most far-out designs. Work, a longtime defense wonk, is a big fan of all of those efforts, calling the research shop the “incubator for discovery, research and innovation” that’s kept the Navy and Marine Corps more tech-savvy than its rivals. But, he added, “the secretary and I consider cost a threat.”