Читать книгу Cyber-physical Systems - Pedro H. J. Nardelli - Страница 29

Systems that have negligible interactions with their environments are called closed systems. In contrast, open systems are interwoven with their environment, exchanging data, matter, and energy. Despite all material systems being open, the concept of closed system is important to indicate the degree of interactions that are external to it. Moreover, such a concept has a great scientific value as it is used to define physical limits and laws of “purified” systems as an abstract object. Moving from a closed (abstracted) to a open (physical) system could be understood as a way to produce a material system from a conceptual one.

The demarcation of the system is key here as well. Once a particular system has its boundaries defined, it is possible to determine if it can be theoretically treated as a closed system. Usually, a closed system is associated with the analysis of the conditions of production, considering either the other two conditions of existence ideal for its functioning or completely neglecting them. The differentiation between closed and open systems is the basis for studying and quantifying their level of organization and uncertainty, as we will see in the next chapters.

Example 2.7 An experimental setting in a laboratory to test the wind turbine can be considered a closed system if everything needed to run such a test is contained there; there are no exchanges with the environment. A wind turbine in a real condition is an open system because it requires kinetic energy from the environment, it converts energy of another kind as an output to supply electricity to the environment, and also dissipates energy in the process of conversion.