查询词典 simultaneous differential equation

Among used machine learning methods, the gradient descent method is widely used to train various classifiers, such as Back-propagation neural network and linear text classifier. However, the gradient descent method is easily trapped into a local minimum and slowly converges. Thus, this study presents a gradient forecasting search method based on prediction methods to enhance the performance of the gradient descent method in order to develop a more efficient and precise machine learning method for Web mining.However, a prediction method with few sample data items and precise forecasting ability is a key issue to the gradient forecasting search method. Applying statistic-based prediction methods to implement GFSM is unsuitable because they require a large number of data items to model a prediction model. In the contrast with statistic-based prediction methods, GM(1,1) grey prediction model does not need a large number of data items to build a prediction model, and it has low computational load. However, the original GM(1,1) grey prediction model uses a mathematical hypothesis and approximation to transform a continuous differential equation into a discrete difference equation in order to model a forecasting model.

其中梯度法是一个最常被使用来实现机器学习的方法之一，然而梯度法具有学习速度慢以及容易陷入局部最佳解的缺点，因此，本研究提出一个梯度预测搜寻法则(gradient forecasting search method， GFSM)来改善传统梯度法的缺点，用来提升一些以梯度学习法则为基础的分类器在资讯探勘上的效率与正确性；而一个所需资料量少、计算复杂度低且精确的预测模型是梯度预测搜寻法能否有效进行最佳解搜寻之关键因素，传统统计为基础之预测方法的缺点是需要较大量的数据进行预测，因此计算复杂度高，灰色预测模型具有建模资料少且计算复杂度低等优点，然而灰色预测理论以连续之微分方程式为基础，并且透过一些数学上的假设与近似，将连续之微分方程式转换成离散之差分方程式来对离散型资料进行建模及预测，这样的作法不尽合理，且缺乏数学理论上的完备性，因为在转换过程中已经造成建模上的误差，且建模过程仅考虑相邻的两个资料点关系，无法正确反应数列未来的变化趋势。

The proposed method is sample and does not need to compute both complex partial differential equation and operator equation of Riccati.

该方法计算简单，无须计算复杂的偏微分Riccati方程或算子Riccati方程。

The boundary value problem for first-order differential equations with a parameter refers to the finite solution condition of equation which includes unknown quantity and its first-order derivative that not only relies on interval value but also relies on the parameter of the equation,which is always settled by fixed point theory or successive approximation method.

含一个参数的一阶微分方程边值问题是指：含有未知量及它的一阶导数的方程的定解条件不仅依赖于在区间端点的取值，而且依赖于方程中的参数。通常它用不动点定理或逐步逼近法来解决。

Reduce the computing complexity of magnetic field integral equation with differential quotient, which makes the computing which combined field integral equation more efficiently.

在AIM算法的实现技术方面作了两个改进：一是采用了新的多极子展开方案，保证了迭代的数值稳定性；二是在差商逼近偏导数的过程中全部采用二阶形式，保证了差商逼近偏导数的精度。

Considering that the temperature gradient through thickness is much higher than that through width and length of plate, in this model, the governing equation of heat transfer was simplified as a one dimensional differential equation, and the series function solution for temperature is established in Lagrangian coordinate setting.

在该模型中，考虑到轧件厚度方向的温度梯度远大于沿宽度和长度方向的温度梯度，因而将热传导方程简化为一维微分方程，基于拉格朗日坐标建立了温度场的级数解法。

The quaternion calculation for spacecraft attitude determination is investigated in this paper,including the transformation between quaternion and the direction cosine matrix,the quaternion differential equation,the selection of time steps for integrating the quaternion equation,and the compensation methods for the noncommutativity error in high dynamic motion.

介绍了四元数计算中的相关问题，包括四元数与方向余弦阵之间的转换、四元数运动方程、求解四元数运动方程时积分步长的选取和高动态应用中非互易误差的补偿，此外还介绍了对偶四元数的发展。

The main works in this paper are as follows:(1). In this thesis, a new method, continuous linearization model, is constructed for the non-linear dynamic systems. The precision Duhamel integration solution for the linearization equation is also given from the theory of linear differential equation. The calculating results show that the new method can improve the calculation precision greatly. In fact, the truncation error is not limited by this method, it can arrive the precision according to the requirement.

本文的主要工作有以下几个方面：(1)由于非线性项的存在，使得多数情况下难以得到非线性动力方程的解析解表达式，目前常使用数值积分方法来求解非线性动力学方程的解，但常规计算方法的计算精度不很理想，本文提出了含Taylor展开项中高阶余项的非线性动力方程的线性化数值计算方法，构造了瞬态线性化方程，给出了Duhamel积分的表达式。

The pressure equation for the liquid phase is obtained as, which is a no-linear elliptic partial differential equation.

推导了喂料熔体流导率的计算公式，得出压力场的控制方程是一非线性椭圆偏微分方程。

The Laplace equation is a typical and simplest elliptic partial differential equation with wide applications.

Laplace 方程是最典型，最简单但应用广泛的椭圆型偏微分方程。

First, theoretical analysis methods were used for the static analysis of the suspension bridge. The formulas for endogen force of the asymmetry suspension bridge through elastic theory were deduced and they were contrasted with those of the normal suspension bridge. The basic differential equation of deflection theory was deduced and the method of getting the roots of the equation was offered, and some simplified methods for deflection theory were presented.

推导了非对称式悬索桥弹性理论的内力计算公式，并对比了其与对称式悬索桥弹性理论的内力计算公式的异同；推导了非对称式悬索桥挠度理论的基本微分方程，并且给出了部分均布荷载作用下基本微分方程的试算方法；提出了挠度理论的几种简化计算方法。

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。