查询词典 gradient method

In this paper, a new edge detection method——method using extremum of first directional derivative is proposed, based upon a general gradient edge model.

文中通过傅里叶变换，在频率域，通过求垂直于边缘的一阶方向导数，并检测其极值点来确定边缘。

The introduction of line searches requires the solution of sub-problems must be a dropped direction, that is g T k δ k 0, In this paper, we study the existed methods of solving sub-problems, prove Zhang and Xun 1999's dogleg method and Steihaug 1983's conjugate gradient method to meet the condition of adequate decrease, then the solution can be used in line search.

引入线搜索要求子问题的解必须是下降方向，即g T k δ k 0，本文研究了现存的子问题的求解方法，证明了Zhang和Xun1999折线法、Steihaug1983共轭梯度法满足"充分下降条件"，得到的解可以安全实施线搜索。

A new hybrid algorithm that combines the chaos method and the nonlinear conjugate gradient method having an effective convergence property is introduced.

本文针对非线性方程组的求解问题提出一种混合算法，将方程组转换成一个优化问题。

Base on the mathematical equation: the quantity of conduction heat flex is equal to the product of heat conduction coefficient and gradient of temperature, we expect to obtain the result which is better than that of Transient Hot-wire Method and Steady-State Parallel-Plate Method, and simplify the strategy of measurement.

理论模式关系中，使用热传量等於热传系数与温度梯度乘积的比例关系式作为理论基础，目的在得到更优於暂态热金属线法(Transient Hot-wire Method)及稳态平行板法(Steady-State Parallel-Plate Method)的量测结果，同时也简化了量测方式。

In this paper, we construct the differential equation to solve the unconstrained optimization problem. Such methods solving the ill-conditioned problems are very effective. It indicates that the asymptotically stable region of explicit the Euler method to solve the differential equation equals to the descent region of the gradient method to solve the original unconstrained optimization problem.

我们发现，在用Euler方法求解二次优化问题的等价动力系统的方程时，由方法的步长确定的稳定区域对应于这些方法所得到的迭代公式的步长满足单调下降算法的条件确定的单调下降区域，因此我们可以利用这个性质构造解无约束优化问题的数值方法而不采用标准的常微分方程的数值求解公式。

The Gradient—Hamilton function method is presented first. Its formula with multiplier function and relax factors quated in solving constrained shape optimization problems is derived. The method is carried out on micro computer to solve shape optimal design of column.

提出了梯度—H函数极值法，并推导出了求解约束形状优化问题时引入的乘子函数和松驰因子的具体公式，在微机上实现了这种方法，并用其解决了立柱的形状优化问题。

The main results of the investigation are as following:(1) Some important criteria for the design of multi-layer structure are acquired: the ratio of the layer thickness to the contact diameter should be controlled to a value about 0.8; increasing the number of the gradient layers and elasticity modulus of the top layer would benefit to the yield strength and the stress status at the interface.（2）By means of molecular dynamics simulations for a indentation and sliding process, it is discovered that dislocations of 45 direction to the surface occur in the surfaces layer, which is correspond to the direction of the plastic flows observed in the macroscopic continuous medium. The irreversible deformation caused by the dislocation and the atom piles at the surface are responsible for the irreversibility of the force response. They are also the main factors for the friction generation. The temperature and the indentation velocity have significant effects on the deformation behaviors of the material of the surface layer. The yield strength would increase obviously if the indentation velocity is greater than 10 m/s.（3）A method to evaluate the fracture toughness of coating by estimating the crack-density functionβof a Wicker''s indentation was proposed. Meanwhile a new surface treatment technology was developed using non-equilibrium plasma.（4）A MD-FE hybrid method and corresponding software was developed to analysis the tribological behaviors for multiplayer system.

研究主要内容和结果有：（1）得到指导梯度膜设计的几个准则：控制膜层厚度与接触半径比在0.8左右为宜；适当增加梯度层层数和顶层弹性模量，有利于提高抗屈服能力和改善界面处的应力状态；（2）通过对嵌入和滑动摩擦过程的分子动力学模拟，发现表层产生一个与宏观连续介质的塑性流动方向观测一致的45 方向位错；位错造成的不可逆变形和表面的原子堆积，是力的响应不可逆性的原因，也是构成摩擦力的主要因素；温度和嵌入速度对材料变形特性有显著的影响，当嵌入速度大于10 m/s时，屈服强度明显增加；（3）提出压痕裂纹密度系数β半定量判定膜层断裂韧性的方法；并开发出表面强化新工艺；（4）开发出分析表面摩擦学特性的MD-FE复合模拟方法和相应模拟软件。

The OTSU algorithm （maximization of interclass variance） is considered as one of the superior threshold selection methods.But this method can not segment the path mark image successfully for our indigenous design and manufactured vision navigation intelligent vehicle under bright illumination.A new method based on regional Roberts gradient is proposed in order to solve this problem.

OTSU法被认为是图像分割中阈值自动选取的最优方法之一，针对自主开发的视觉导航区域交通智能车辆的导航路径在强光照条件下不能直接应用此方法取得准确分割效果的问题，提出了一种基于区域的罗伯特梯度算子的图像分割方法。

Two special cases are discussed: flow due to a constant pressure gradient and flow due to a periodic one; In chapter 4, on the basis of the method of fractional element proposed by Schiessel et al and of the generalized fractional element networks proposed by Xu and Tan and by the use of discretization method for solving the inverse Laplace transform, we obtain the creep compliance of Zener and Poynting-Thomson models which are composed of the generalized fractional element networks.

并讨论了如下两种特殊情形：常压力梯度下的流动和周期性压力梯度下的流动；第四章在Schiessel等提出的分数阶单元法和徐明瑜等提出的广义分数阶单元网络的基础上，应用离散求逆Laplace变换的方法，给出并讨论了广义分数阶单元网络Zener和Poynting-Thomson模型的蠕变柔量。

In the ***, all types and fundamental principles of Radon transform are summarized systematacially. This *** starts from the general linear Radon transform, and then researches how to use the damped least square method to find the solution of the forward transform. However, the least squares smoothing effect will lead to a certain degree of trails in the data of Radon domain, which led to the application\'s limitations. After that the implementation in Radon domain and relative merits of linear Radon transform, parabolic Radon transform and polynomial Radon transform which have time invariance are introduced, the conjugate gradient method that can solve numerical solution is also given. And then the high resolution Randon transform is discussed, it introduces the regularization theory and Bayes principle into inversion, which successfully remove the negative affect caused by discrete Radon transform. Finally, we introduce the optimal weighting similar coefficient Radon transform, which adapt to the time variant quality of hyperbolic Radon transform.

本文系统总结了Radon变换的各种类型及其基本原理，从τ- p变换(即一般线性Radon变换)出发，研究利用阻尼最小二乘平方法求解其正变换，但是最小平方法的平滑作用会导致Radon域数据存在一定程度的拖尾效应，给这种方法的应用带来了很大的局限性；然后先容了具有时不变性的线性、抛物和多项式Radon变换在频率域的实现及其优缺点，给出了求解其数值解的共轭梯度算法；接着讨论了高分辨率Radon变换，它把正则化思想和贝叶斯原理引进到了反演中，很好的克服了离散Radon变换产生的截断效应对结果的不利影响；最后先容了适应双曲Radon变换时变性质的高分辨率最优相似系数加权Radon变换。

It was just a normal day of school

那只是上学的普通一天

Which is a very good reference in this issue.

这是一个在这个问题上很好的参考。