Based on the classical demonstration methods of GJB,fuzzy demonstration of maintainability index is offered,and fuzzy hypothesis test for the parameter of lognormal distribution is studied.

This article is aimed to describe the distribution figure on the frequency histogram of geotechnical parameters which obey lognormal distribution,the method of normal checking on the cumulative frequency probability grid paper as well as the statistical method for finding characteristic figure values of parameters,and finally to make the statistics of geotechnical parameters more rational.

They also have suggested that the lognormal distribution of quantitative trait would be more reasonable.

With the help of the large quantity of flight data,We research the distribution of the compared damage that was caused by flying,consist of normal,lognormal and weibull distribution.

The results of simulation demonstrate that under the condition of fixed buffer size,the calcu- lation based on lognormal-FARIMA model provides much less loss rate.

On the basis of the shear_lag theory,this paper studies the microstress redistributions induced by the interaction of failure of 90° layers and the breakage of some fibers in 0° layer in cross_ply laminates under tension in 0° direction.