THE INVERSE EIGENPROBLEM WITH RANK-ONE UPDATING AND ITS STABLITY

Let ∑, Г be two n-by-n diagonal matrices with σi,γi as their diagonals. For the inverse eigenvalue problem: look for y∈Rn such that Г + yyT is similar to ∑, we prove thatu also the sufficient condition for the solvability of this inverse problem. Its solution (set) is given explicitly. In some case, the problem is unstable. But we prove that the sums of the square of some contigious components keep stable, i.e., small sum keeps small, large sum has a small relative perturbation, see Theorem 3.     

基于PX4构建高可靠多旋翼控制器的实现方法

多旋翼无人机是当前备受关注的热点,虽然功能强大,但在日常飞行中仍存在可靠性不高的问题。本文以PX4开源飞行控制器为基础,使用Arduino单片机平台构建低成本的高可靠性多旋翼无人机控制器,用于提升现有的多旋翼无人机的可靠性。主要介绍了冗余切换装置以及坠落预警装置的原理和结构,并进行了相应的实际测试以验证系统运行的效果。     

A NOTE ON SENSITIVITY ANALYSIS OF SHAPE-FROM-MOMENTS

The shape-from-moments problem is to reconstruct a planar polygon from a set of its complex moments. To reconstruct a polygon means to estimate the vertices and the ordering of the vertices. We notice that some coefficients are very important in finding out the ordering of the vertices. We introduce sensitive factors for the coefficients and use it to analyze sensitivity. These factors are also useful for the sensitivity of the vertices.