A new kind algorithm of Kriging based on the Linear Programming (LP)is proposed to take the constrains of nonnegative weights into consideration,and this new method not only makes the use of LP's properties of easy and fast caculation,but also avoids the heavy caculation and subjective affection that existed in the other methods with nonnegative weights.

The existence and uniqueness of nonnegative solution for a class of age-structured SEIR epidemic model;

By using pure analysis method,are proved the monotone stability,existence and uniqeness of a dynamic state nonnegative solution of a repairable syatem with some singleness components.

This paper deals with the existence of nonnegative solutions to boundary value problems 1p(t)(p(t)y′(t))′+a(t)f(t,y(t))=0, lim t→0+ p(t)y′(t)=0=y(1) where p∈C 1 (0,1) with p>0 on (0,1),f≥0,f(t,y) is nonincreasing with respect to t for each fixed y and nondecreasing with respect to y for each fixed t, and a∈C(0,1) may change sign.

Combinatorial structures on nonnegative matrix with zero trace;

Estimation of new bounds on the spectral radius of nonnegative matrix;

The installation of "new bound" for spectral radius of nonnegative matrixs;

Combined the characteristics of three forecast methods,a forecast model with non-negative weights is proposed.

Taking Cauchy convergence theorem as the basis,puts forward a new discriminance to decide convergence or divergence of two kinds of generalized integral of nonnegative function f(x),demonstrates the accuracy and effectiveness of this discriminance by proving.

New methods for discriminating convergence of nonnegative function s infinite integral are given.