Model – an object, which in certain circumstances, may replace the original, reproducing the interesting properties and characteristics of the original. There are two classes of models: analytical and simulation. In the analytical models behavior of a complex system can be written in the form of some functional relations or logical conditions. The most complete study can be carried out in the case where the explicit dependence of linking the unknown values to the parameters of a complex system and the initial conditions of its study. However, this can be done only for relatively simple systems. For complex systems, researchers have to go to the simplification of the real phenomena giving the opportunity to describe their behavior and to provide interaction between the components of a complex system.
This allows you to learn at least some general properties of complex systems, for example, to assess the stability of the system, reliability characteristics, etc. To construct mathematical models is a powerful mathematical tool Availability mathematical apparatus and the relative speed and ease of obtaining information about the behavior of complex system contributed to the widespread and successful dissemination of analytical models for analyzing the characteristics of complex systems. When the phenomenon in a complex system is so complex and varied that the analytical model becomes too rough approximation to reality, a system analyst is forced to use simulation. In the simulation model the behavior of the components of a complex system described by a set of algorithms who then sell the situations that arise in a real system. Modeling algorithms are designed based on initial data, containing information about the initial state of a complex system, and the actual values of the parameters of the system display the real phenomena in the system and obtain information about the possible behavior of a complex system for this particular situation.