In twenty-first Century, information technology has rapidly permeated into every field of human
society. Form the Large national or international fields to the small families or individuals, more and
more people use of information technology to provide convenient, fast and efficient work and business.
The expanding demands of All walks of life prompted the investment and the scale of informatization
construction from the underlying physical layer to the top of the application system constantly strengthen
intensify. In the imperceptibly we have entered into a new era, the information age.