Some basic concepts in modern design theory

In the long march of development of design theories, many terms have been coined for explaining their new ideas. Some times one term is used by different authors with different definitions or different means, say concepts. Other times different terms are used by different authors with the same mean or concept. It is rational and necessary for the modern design theory in the way of its growth to examine the definitions, means and concepts of all these terms. In considering the character of global economy and the change in manufacturing, some new definitions, means and concepts have been given to the terms for working with the theory and related methodology, and form a base of the development of the theory. The purpose of the paper is to summarize existed results and call further study on the definitions, means and concepts of such terms to match the state-of-the-art requirements. Insufficient in precision use of a term will occasionally lead to a different result in theoretical research. The concepts of performance, function, quality, constrain, requirements, features, requirement driving, state etc. studied and used previously in the modern design theory are collected and discussed.