Читать книгу Cyber-physical Systems - Pedro H. J. Nardelli - Страница 32

The Maxwell's demon experiment is a human‐made conceptual dynamic closed system. It is human made because this thought experiment only exists as a human‐made theoretical construction. In this case, it is a conceptual system because it does not have a material realization. If we consider an experiment proposed in [12], then we would have a material system; this case will be analyzed later on. The system is dynamic because it changes its states over time. It is interesting to note that there are two interrelated levels with respect to the system dynamics: (i) system‐level considering variations in macrostate properties like temperature or entropy, or (ii) molecular‐level considering the movements of the molecules; these microstates are related to, for example, their individual velocity or position. The interrelation between the macrostates and the microstates is of extreme importance and will be presented in the next chapter, where we will focus on uncertainty. By definition, Maxwell's demon is an isolated system without any in‐ and outflows, and therefore, it is a closed system.