Man-Machine-Environment System Engineering: Proceedings of the 21st Conference on MMESE is the academic showcase of best research papers selected from more than 500 submissions each year. From this book reader will learn the best research topics and the latest development trend in MMESE design theory and other human-centered system application. MMESE focus mainly on the relationship between Man, Machine and Environment. It studies the optimum combination of man-machine-environment systems. In the system, the Man means the working people as the subject in the workplace (e.g. operator, decision-maker); the Machine means the general name of any object controlled by the Man (including tool, Machinery, Computer, system and