查询词典 local minimum

BP neural network based on adaptive UKF is introduced in this paper for the standard BP neural network has slow converges,local minimum value and weak generalization ability.It can train weight of BP and improve the efficiency of BP without linearization by using the frame of Kalman filters and adaptive factor to adjust the variance of dynamic model.

1引言1986年，Rum elhart和M cC lelland等人在多层前向神经网络模型的基础上，提出了误差反向传播学习算法(BackPropagation简写BP)，该算法是目前在神经网络中应用最广泛的算法，它解决了多层前向神经网络的学习问题[1]。

Focusing on the disadvantages in the BP neural network such as low convergence rate,easily falling into local minimum point and weak global search capability,a new method that used GA to train BP neural networks to gain best weights was presented.

针对传统的BP算法存在收敛速度比较慢、容易陷入局部极小值以及全局搜索能力弱等缺陷，提出了神经网络与遗传算法。结合的方法，采用遗传算法。练BP神经网络，优化网络权值。

The best theoretical solution to a partitional clustering problem is to find all possible partitions and choose the partition that minimizes the objective function. However, the enumeration of all possible partitions is impractical even for data sets of moderate size. Therefore, as an alternative, most partitional approaches use an iterative optimization technique. And this could be cause local minimum.

本文在分析了目前聚类的基本方法的基础上，指出以K平均法等为代表的分割聚类虽然理论上找到类的所有划分并使得目标函数最小就可以获得最优解，但由于对于相当尺度的数据集列举所有可能的划分并不现实，因而多数分割方法采用迭代优化技术作为变通。

Then a global separable nonlinear least-squares identification method which estimates the time delays and transfer function parameters separably is derived to reduce the possibility of convergence to a local minimum by using the global optimization theory.Furthermore,the GSNLS method is modified to a novel global separable nonl...

为降低收敛于局部最小的可能性，利用全局优化理论，推导了全局可分离的非线性最小二乘辨识方法；为消除强观测噪声所引起的参数估计的偏差，将GSNLS方法调整为一新颖的全局可分离的非线性多新息递推最小二乘辨识方法，仿真实验验证了算法的有效性。

This method avoids overfitting, underfitting and local minimum in neural networks.

这种方法避免了在人工神经网络中的过学习、欠学习以及局部最小化的问题。

In the 1990s, a more complete theoretical system - the achievement of statistical learning theory and neural networks, and other than because of the emerging machine learning methods of the difficulties encountered some important, such as how to determine the issue of network structure, overfitting and underfitting, the local minimum points ect, makes the rapid development and improvement of SVM in resolving the small sample, non-linear and high-dimensional pattern recognition problems in the performance of many unique advantages and can function to promote the use of fitted function and other machines learning problems.

上世纪90年代，一个较完善的理论体系--统计学习理论( Statistical Learning Theory，简称SLT)的实现和由于神经网络等较新兴的机器学习方法的研究遇到一些重要的困难，比如如何确定网络结构的问题、过学习与欠学习问题、局部极小点问题等，使得SVM迅速发展和完善，在解决小样本、非线性及高维模式识别问题中表现出许多特有的优势，并能够推广应用到函数拟合等其他机器学习问题中。

In the paper, the BP Neural Network is introduced to pick up the first break. And aiming at the shortcomings of BP neural network, such as the low speed in training, the tendency to local minimum, the limitation of amplitude, the momentum factor method and the self-adjusting learning rate are used to improve the BP algorithm.

将BP神经网络引入到初至波拾取中，并针对经典BP神经网络收敛速度慢、易于陷入局部极小的缺点，利用组合函数法、限幅法、动量因子法及自适应学习率法等进行了改进。

However, MM can also provide important dynamic parameters, such as energy barriers between different conformers or steepness of a potential energy surface around a local minimum.

但是 MM 也能提供重要的动力学数据，例如不同构象之间的势垒或者势能面最小点附近的坡度。

A large releases of kinetic energy for channel CH3CS++ H of least energy might result from a dissociation mechanism according to which c-C2H4S+ isomerizes to a local minimum CH3CSH+ and then dissociates through a transition state to form CH3CS++ H. On the other hand, a predicted dissociation energy 11.05 eV for c-C2H4S ?

实验中观察到环硫乙烯离子解离成CH3CS++ H的解离通道释放出大量的平均动能，并采用G3计算预测环硫乙烯离子的解离通道，推测环硫乙烯离子异构化至次稳定态CH3CSH+结构，再经过渡态结构，断裂S-H键生成C2H3S+和H，同时释放出大量的动能。

Furthermore, an off-trap strategy of quasi-human approach is put forward in order to avoid frequently jumping into local minimum during the quasi-physical computation.

为求解蛋白质结构预测问题提出了三维欧氏空间连续模型，并为由此形成的数学问题找到了相应的物理模型，应用拟物的方法对其进行求解。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。