The probability tomography,which is defined as the cross correlation product of the total observed electric field component and the scanning function, divided by the square root of the product of respective variances , is a new interpretation for the recognition of buried charges.

Probability tomography, as a new potential approach of geophysical interpretation, is based on the relation between the measured surface electric field and the scanning function.

The approach of probability tomography defined as the cross-correlation product of the total observed electric field components and the scanning function normalized by the square root of the product of respective variances, is used for the recognition of buried charges.

For the nonlinear problem of simple guided munitions guidance and control system,description function is adopted to design the velocity autopilot including three types of nonlinear sections.

Then,the design of self oscilating electronic ballast using control tools such as description function,extended Nyquist criterion has been carried out.

With respect to a class of fuzzy pre-estimate control systems,robust stability of the primary loop and the secondary loop is analyzed with description function and magni -tude-phase property respectively in this paper.

This paper presents a new simple method for calculating the descriptive functions.