Ren - Cang Li

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The double angle theorems of Davis and Kahan bound the change in an invariant subspace when a Hermitian matrix A is subject to an additive perturbation A ! e A = A+A. This paper supplies analogous results when A is subject to a congruential, or multiplicative, perturbation A ! e A = D AD. The relative gaps that appear in the bounds involve the spectrum of(More)
In this article, the evaluation technology is proposed for optimal operation scheme based on safety water supply, in order to verify the security and economy of the optimal operation scheme and provide the evidence for optimal operation decision-making. Four evaluation indices, named flow coincidence, pressure coincidence, pump efficiency and direct power(More)
The solution to a general Sylvester equation AX−XB = GF ∗ with a low rank righthand side is analyzed quantitatively through Low-rank Alternating-DirectionalImplicit method (LR-ADI) with exact shifts. New bounds and perturbation bounds on X are obtained. A distinguished feature of these bounds is that they reflect the interplay between the eigenvalue(More)
GPS (Global Positioning System) have high position and velocity precision, star sensor is a high accuracy attitude measurement system, SINS (Strapdown Inertial Navigation System) can get all navigation information precisely at short period. In order to realize high-precision navigation, according to analyze the error model of above systems, both of the(More)
Method of identifying the dynamic model of accelerometer on precision centrifuge is studied in this paper. Through the method of improved Levy's identification, using only the accelerometer magnitude frequency response data, the accelerometer's dynamic mathematical model can be identified expressed in transfer function. The practicability and effectiveness(More)
A color image of digital camera is obtained by interpolated CFA (Color Filter Array) data from single sensor digital camera. Using JPEG compression method to interpolated data, the maximal compression ratio is less than 90:1. In this paper, an improved compression method is discussed which applied JPEG compression to raw data after two luminance components(More)
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