Whatever you are, a scientist, a manager, an architect, a lawyer, a notice or a successful scholar; and no matter whatever you are diligent, or lazy, in the modern work, study and life , you always need our common good friends – computers.
    A computer is an erudite tutor, and a talented secretary who can draw up documents, manage data, design blueprints, type papers and so on. Furthermore, the computer is the most obedient and diligent “house-keeper” or “servant” of housewives; it is also a game expert admired by children. Oh, the computer is really a welcome fellow of ours.

    Office Automation (OA) is the application of the computer and communication technologies to improve the productivity of clerical and managerial office workers, The major functions of the OA system include text processing, electronic mail, information storage and retrieval, task management, and etc.. Today, there have been many OA systems, for example, desktop publishing, video conference, videotext and so on. So, many office workers can easily find the information they want through a personal computer sitting on his or her desk, It changes substantially the way people work in an office.

       For many years, researchers have been exploring the way people think in hopes of creating a computer that thinks like a person. This is so called Artificial Intelligence (AI). It aims at producing a computer system that will be able to communicate with us by speech and hearing, and be capable of solving intelligent problems. One practical application of AI has been in the area of expert systems. An expert system is a computer program that solves the specialized problems at the level of a human expert.

     CAI is an educational concept that places the student in a conversational mode with a computer that has a preprogrammed study plan. The programmed course selects the next topic or phase of study according to previous responses from the student, allowing each student to process at a place directly related to his or her learning capability.

     An expert system is a software system having some domain knowledge, which can solve some problems for people. Its performance depends on the facts and the rules that are fed into the computer. The expert knowledge is gathered by knowledge engineers from human experts in the field such as medicine, engineering, or geology. For example, in the field of medicine, one question that might be asked of an expert system is whether one treatment is better for a patient than another one. An expert system has the capacity to store the collection of knowledge and manipulate it in response to user’s inquiries, in some cases, it can explain responses to the user.