Читать книгу Cyber-physical Systems - Pedro H. J. Nardelli - Страница 26

Through this classification, natural systems are the ones that come into being by natural processes without human intervention. Natural systems thus exist. Human‐made systems are the ones that exist (or have potential to exist) by human intervention, i.e. humans are their agents of production. There is also a hybrid class, called human‐modified systems, where either human made and natural subsystems are part of the same system, or humans directly intervene in natural systems.

The correct classification is clearly related to the demarcation of the system. In some sense, all systems on the planet Earth are human modified; however, classifying it as human made or natural may indicate the most important determinations for the particular system that is analyzed in the specific context in which it exists (or may potentially exist).

Example 2.4 The car and the wind turbine presented in the previous sections can be classified as human‐made systems. The atmosphere of the planet Earth can be classified as a natural system as it has come into being without human intervention. However, in specific places where there are too many cars, or too many wind turbines, the atmosphere may change its internal dynamics because of different air composition that is due to chemical residues produced by cars or because of variations in air flows caused by turbines. In these cases, there is a human intervention and we could say that, in those specific regions, the atmosphere becomes a human‐modified system.