TABLE OF CONTENTS 
Dreams are sometimes so realistic that they seem to take place in the real world. The brain, an incredible network of billions of interconnected neurons, allows us to have the impression of experiencing seemingly impossible situations. Who has never flown in their dreams? This simulation becomes possible in everyone s dreams.
The nanoworld exists within computers. Miniaturization of devices and their massive integration into systems continually increases our ability to calculate, increases the speed of information retrieval from databases, and allows for a virtual representation of physical objects or complex systems.
Simulation is used to analyze how products react to different situations before their construction (eg planes, vehicles), to determine the parameters used in the production process and to predict the results before starting production (eg integrated circuits). In other words, to test the products in a thorough and rapid manner without the costly risks for those who finance the projects. Computer-aided design (CAD) helps humans to manage complex systems.
CAD enables us to predict the future. Weather forecasts, for example, predict the weather in the short term and have enough precision to allow us to implement the necessary precautions in a worst case scenario, as is the situation with storm forecasting.
Simulation has become an indispensable research tool which enables all physically impossible experiments to be carried out to test any given theory. As with the problem of global warming, the long-term global projections are carried out using models that have been tested...
