Over the past decade, there has been much development in the basic elements of physical security systems. These elements include perimeter sensor systems; entry controls such as coded cards and more sophisticated computerized identity verifiers; video assessment; access delay accomplished by fixed barriers, guards, or dispersibles; security alarm systems; and guard equipment and training. Development has been devoted to capabilities, reliability of components, vulnerability to malevolent acts, and ease of operation and maintenance. In addition, much effort has been put into the development of complete system concepts. Because of demands associated with increasing terrorist threats, a number of ongoing projects are exploring new areas. One area is the development of expert systems capable of performing exterior perimeter sensor layouts by applying design rules. Such systems also could be developed for designing facility lighting, video assessment, and security system maintenance. Sandia National Laboratories, the U.S. Department of Energy's lead laboratory for physical security research, is also developing a self-contained robot with an onboard microprocessor, transceivers, and a closed-circuit television camera; a teleoperated research vehicle; and an artificial intelligence/robotic sentry program. 4 figures and 23 references.