Informationally open systems and reduction of wave packet

For description of evolution of quantum systems when information about them is transmitted to the physical surrounding, the Schroedinger equation with stochastic parameters (Schroedinger-Stratonovich equation) is suggested. In the framework of the physical concept of informaly open systems a dynamical theory of measuring process is elaboarted for the case of strong and weak interactions of a macroscopic measuring apparatus. The connection between this theory and classical stochastic dynamics as well as transition to the quantum stochastic fields are discussed. It is shown that both individual and statistical descriptions of the system is possible. 9 refs