查询词典 existence of extremum

Existing particle swarm algorithm and its variations converge slowly and get into local extremum easily. Due to this, based on the characteristics of current conceptual designing, an improved particle swarm optimizational model based on dynamic niche is proposed in this paper.

现有的微粒群算法及其变种都有着收敛速度慢、容易陷入局部极值问题，再针对目前创新概念设计的特点，本文提出一种改进的基于动态小生境的微粒群优化模型。

A hybrid particle swarm optimization algorithm based on the chaos search is proposed. It can not only overcome the disadvantage of easily getting into the local extremum in the later evolution period, but also keep the rapidity of the previous period.

所提出的算法将粒子群优化算法和混沌算法相结合，既摆脱了算法搜索后期易陷入局部极值点的缺点，同时又保持了前期搜索的快速性。

This thesis analyzes the reasons of the local extremum in Mi-based image regitstration, then implemented an improved method, which is integrated previous information to get a more smoothly object function and overcome interpolation artifacts effectively. Experimental results show that this methods registration accuracy is improved and can be applied.

本文分析了基于互信息的图像配准过程中出现的局部极值问题，实现了一种结合先验信息获得更加平滑的目标函数的方法，并通过实验证明了该方法的有效性。

Some methods have been used to overcome the local extremum of MI function, such as use high-order interpolation, decrease gray level, use Median filter.

许多学者对此做了大量研究，提出了诸如高阶插值法、减少灰度级数、中值滤波等解决方法。

In scale space,the local extremum ofwavelet transform modulo of image not only describes the local characteristics of ir-regular structure of image but also displays distribution of local singular point s.

在尺度空间，图像的小波变换模局部极值能在刻画图像不规则结构的局部特征的同时，给出它们的局部奇性点的分布。

The fault diagnosis of Fuzzy ANN is realized by the Neural Network Toolbox of MATLAB. The result is proved valid, but also proved easy to be trapped in the local extremum.

这里以BP网络为应用模型，把模糊化后的故障特征参数作为网络的输入样本，对样本数据训练、仿真，应用MATLAB提供的神经网络工具箱函数实现了模糊神经网络对设备故障的诊断，结果证明了该诊断模型的有效性，但也暴露出BP算法易陷入局部极值的弱点。

The essence is how to use the mine microseism, under the unchanged mining intensity, which occurs upon accumulation of the respective low stresses, to predict the next extremum mine microseism due to occur during the stress mining environment classified by the increased isostress gradient instead of a period divided by the human experience.

其实质是在开采强度保持不变的前提下，用各自较低应力环境累计发生的矿山微震，预测下一个按等应力梯度增高的应力强度环境开采期间将要发生的极值矿山微震，而不是人为经验划定的某一时段。

According to the characteristic that the definition point of the Q matrix of wave front is always located on the extremum point on the axis of the beam, a three-dimensional formula for the rectificative factor of phase in complex ray paraxial approximation is proposed, which calculates the rectificative factor of phase directly without considering the calculation of the main directions and curvatures and the rotation of the coordinates, thus simplifying the paraxial approximation calculation by the complex ray expansion method.

根据波前Q矩阵的定义点总位于波束轴上极值点的特点，提出了三维复射线近轴近似相位校正因子计算公式。该公式不用考虑主方向和主曲率的计算和坐标旋转，直接计算相位校正因子，从而简化了复射线展开法的近轴近似计算。

It's regretted that the multi-extremum theory of portfolio selection with different fat tails is still a problem that needs to be resolved.

遗憾的是，具有不同厚尾的股票组合的多元极值分布理论，到目前为止仍然是有待解决的问题。

The genetic algorithm pays attention to unknown area search . It has high speed and relative low precision. It will not get into local extremum. The BP algorithm searches the area that include whole-space minimum. It can improve speed and recision.

遗传BP算法利用遗传算法进行全局搜索，注重搜索未知区域，处理速度快而对精度要求不高，不易陷入局部极小点，而利用BP算法搜索有最优点的区域，提高搜索速度和精度。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。