ABSTRACT
Over the years, machines of all kinds have improved and become more reliable. However, machines typically operate as components of larger systems, such as transportation, communication, manufacturing, defense, health care, and so on. Although many aspects of such systems can be and have been automated, the human operator is retained in many cases. This may be because of economics, tradition, cost, or (most likely) capabilities of the human to perceive patterns of information and weigh subtle factors in making control decisions, which the machine cannot match.
