Early Tools and Machines Already in early cultures men aimed at the expansion of their physical power in order to facilitate work processes. In prehistoric times first tools made of stone were developed and some thousand years later followed by the invention of simple mechanical devices and machines such as the wheel, the lever and the pulley. Next came the construction of powered machines. Waterwheels, windmills and simple steam-driven devices did no longer require human strength to be operated. In China for example trip-hammers powered by flowing water and waterwheels were already used some 2,000 years ago. Besides tools and machines, which helped to extend men's physical power also devices to support mental faculties, especially in the field of mathematics, were invented. As soon as 3000 BC the abacus was developed in Babylonia. By using a system of sliding beads arranged on a rack early merchants could make computations, which helped them keep track of their trading transactions. Also, early "industrial-robot devices" were developed as soon as 250 BC. The clepsydra, or water clock, which improved upon the hourglass by employing a siphon principle to automatically recycle itself, was constructed by a Greek inventor and physicist, Ctesibius of Alexandria.

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Expert system Expert systems are advanced computer programs that mimic the knowledge and reasoning capabilities of an expert in a particular discipline. Their creators strive to clone the expertise of one or several human specialists to develop a tool that can be used by the layman to solve difficult or ambiguous problems. Expert systems differ from conventional computer programs as they combine facts with rules that state relations between the facts to achieve a crude form of reasoning analogous to artificial intelligence. The three main elements of expert systems are: (1) an interface which allows interaction between the system and the user, (2) a database (also called the knowledge base) which consists of axioms and rules, and (3) the inference engine, a computer program that executes the inference-making process. The disadvantage of rule-based expert systems is that they cannot handle unanticipated events, as every condition that may be encountered must be described by a rule. They also remain limited to narrow problem domains such as troubleshooting malfunctioning equipment or medical image interpretation, but still have the advantage of being much lower in costs compared with paying an expert or a team of specialists.

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