奇异线性变换

In this paper, taking the downward continuation of potential field as an inverse problem of upward continuation, we obtain a convolution type linear integral equation for downward continuation. Making use of the orthogonal symmetry characteristic of Fourier transform matrix, and combining the principles of singular value decomposition of matrix and generalized inverse, we proposed a stable generalized inverse method for downward continuation of potential field, called wavenumber domain generalized inverse algorithm, which doesn't need the computation for inverse matrix. It resolves the instability of potential field downward continuation of large depth.

本文通过把位场向下延拓视为向上延拓的反问题，得到向下延拓的褶积型线性积分方程，再利用Fourier变换矩阵的正交对称特性，并结合矩阵的奇异值分解和广义逆原理，提出了一种稳定的不需要进行求逆运算的位场向下延拓广义逆方法——波数域广义逆算法，解决了位场大深度向下延拓的不稳定性问题。

To weaken the influences of the position-dependent periodic disturbances and parameter uncertainties, the robust repetitive controller was designed, which associated structure singular value theory with the discrete-time repetitive control theory. The problem of robust repetitive control was transformed into one of H∞ optimal control using linear fractional transformation. The robust repetitive controller was achieved using D-K iteration procedure and made the servo system have stability, robustness and tracking performance.

为了削弱周期性扰动及参数变化不确定性的影响，将重复控制和结构奇异值理论相结合，利用线性分式变换(linear fractional transformation，LFT)将鲁棒重复控制问题转换成H∞最优控制问题，采用D-K迭代法设计鲁棒重复控制器(robust repetitive controller，RRC)，实现系统的稳定性和鲁棒性，提高系统的跟踪特性。

ABSTRACT Some of the problems raised from the H〓 control theory and its applications are studied deeply in this dissertation. They are system model description in robust design problems---linear fractional transformation, singular H〓 problem which occurs when some of the conditions of the standard H〓 problem are not met, and the quadratic stabilization problem is studied from the point of H〓/μ synthesis.

本论文对H〓控制理论及应用中的一些问题进行了深入的研究，着重解决了鲁棒设计问题中的系统模型描述---线性分式变换，以及当H〓标准问题的某些条件得不到满足时所出现的奇异H〓问题。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。