Computers are widely used in industry to improve productivity at both the design stage through computer-aided design (CAD) and the manufacturing stage via computer-aided manufacturing (CAM). The ability of some computer systems to perform in ways that would be considered intelligent if observed in humans is referred to as artificial intelligence (AI). Currently the four main types of AI systems are intelligent agents, expert systems, neural
networks, and robotics (the study of robot technology). Robots for military, business, and personal use are available today.