查询词典 approximate method

Combining the definition of CWT and the derivative property of convolution, we constructed a general method to calculate the approximate derivative of signal through CWT by using the first and second derivative of Gaussian function, Haar, and the first derivative of three-order-Spline function as wavelets. As compared with the other approaches of calculating derivative, which include the numerical differentiation, polynomial filters, Fourier transform, and the recently proposed DWT method, fast calculation and simple mathematical operation were remarkable advantages of CWT method. For the signal corrupted by severe noise (Signal-toNoise Ratio=5), the satisfactory results could also obtained via CWT method through appropriately adiusting the dilations.

在此基础上，(1)结合连续小波变换的特点和卷积的微分性质，提出了使用Gaussian函数的一阶和二阶导数，Haar和三次样条函数的一阶导数作为小波函数的连续小波变换计算信号近似导数的一般性方法，与其他导数计算方法(包括数字微分法，多项式滤波法，Fourier变换法和离散小波变换法)相比，本法简单便捷，计算速度快，对于噪声含量较高的信号(S/N为5)，只要适当调节尺度即可获得比较满意的结果。

With the advancement of science and technology, some new theories and new ways emerged gradually, some of them merged with specific theoretical tools, this specific theoretical tools include mathematical morphology, fuzzy techniques, neural networks, wavelet and so on. Secondly, in this paper, it described and analyzed the segmentation method based on the edge in the domain of image segmentation in detail. It did experiments on several edge detection operators using MATLAB, it summarized the advantage and the shortcoming of traditional edge detection operators, and the operating environment. On the basis of the experimental analysis, it implemented an edge location more precise, more efficient operating speed edge extraction method——Template Vector. In this method, it optimized differential approximate calculation of first differential operators the paper mentioned. After experimented on this edge extraction method, contracted with the traditional methods, the edge outline is extracted more accurately and more exquisitely, furthermore, it retained the object outline furthest, and achieved more satisfied edge extraction result.

其次，对图像分割领域中常用的基于边缘的分割方法进行了详细的研究与分析，对各种边缘检测算子进行了MATLAB环境下的实验，分析总结了各种传统边缘检测算子的优缺点和适应环境，并针对传统边缘检测算子在处理显微图像时的缺陷，在实验分析的基础上研究并实现了一种边缘定位更加精确、运算速度更加快捷的边缘提取方法——模板向量算法，在该算法中，对文章提到的一阶微分算子中微分的近似计算作进一步优化，经过对该边缘提取方法进行实验，其结果与传统方法相比，轮廓提取更为精确细腻，且最大程度的保留了图像中物体(目标个体或者明显噪声点)的轮廓，得到了比较理想的边缘提取效果。

So, in this thesis, discussing the interrelated theory and by using finite element method,fixed Supported Square Plates with openings for different location and size of the openings are investigated. The mechanics rule of plates after openings are presented. A comparison is made for the above plates and the plates supported in three sides and the cantilever of plate in approximate boundary conditions. Some approximate results are obtained.

为此，本文论述了钢筋混凝土板的相关理论并用ANSYS软件分析了四边固支开孔板在不同开孔位置和形状、不同开孔面积的情况下内力的改变，获得了内力改变的规律，并和三边固支板、悬挑板在近似的边界条件下的受力倩况进行比较，得到一些相近的结果。

In the method, the symmetric positive semidefinite matrices are updated to approximate the Hessian matrices of the elemental objective functions and their sum to approximate the Hessian matrix of the objective function.

算法用对称半正定矩阵作为元素目标函数的Hessian阵的近似，使得其和仍然保持目标函数的Hessian阵的某种稀疏性。

This method corrected the Wien approximate based on the mathematical principle, and calculated the spectral shape using ADE to identify the band which had the maximum and minimum emissivity, then deduced the relationship of each band's emissivity after the correction of Wien approximate and derived the actual emissivity using this relationship and MMD model.

对维恩近似从基本原理上进行修正，利用ADE计算光谱大致形状以确定发射率最大最小的波段，推导出了在修正维恩近似后各个波段发射率的关系，再利用这个关系以及最大最小值差模型计算实际的发射率。

The implementation is that users first give the approximate execution time of threads and then create treads according to the descending sort of the approximate values, finally the treads will be placed on processors by the system with a Greedy Method.

在线索分配策略方面，我们首先提出了在多线索体系结构中，侧重处理机负载平衡的线索分配策略的实现方法，即用户给出线索运行时间的估算值并按估算值的递减顺序生成线索，再由系统采用贪心算法进行线索分配。

By introducing the nonlinear complementarity problem function, the Karush-Kuhn-Tucker conditions of OPF model are transformed equivalently into a set of semismooth nonlinear algebraic equations. Then the set of semismooth equations can be solved by a semismooth L-M method based on the subdifferential. The method belongs to Newton-type method. It can ensure the positive defmitiveness of the iterative coefficient matrix by using the L-M parameter, which avoids the ill-conditioning of iterative equations. The method, requiring only the approximate solution of a linear system at each iteration, is quite applicable to the large-scale cases.

在利用非线性互补函数将OPF模型的KKT条件转化为半光滑非线性代数方程组后，采用基于次微分的半光滑L-M法求解，该方法属于牛顿法范畴，可通过对L-M参数的调整保证迭代系数矩阵的正定性，克服了系数矩阵的奇异引起的"病态"，且该方法在确定搜索方向时只需求解线性系统的加热器近似解，适用于大规模系统的求解。

By study the method of approximate development of surface of revolution,the mathematiccal model of approximate development,precision analysis and error correction has been gained.

通过对不可展回转曲面近似展开方法的研究，得到了回转曲面近似展开、精度分析和误差矫正的数学模型。

Then, the relation between vibration and sound, the acoustic holography method, the indeterminacy and identifiability of BSS, the BSS algorithm are discussed in detail. Based on above researches, the dissertation is divided in following four sections. The first section investigates the BSS algorithm suitable to acoustic feature separation. The algorithm of the joint approximate diagonalization of eigen-matrices is proposed. The spectra or the time-frequency distributions of source signals are the interesting features in ABD and they are separated from mixing signals by JADE algorithm. Then, the convolutive mixing model is transformed into a high-dimension instantaneous mixing model, and the deconvolution of source signals is achieved by the joint approximate block diagonalization of eigen-matrices. The proposed algorithm has a global minimum, and it is unsensitive to noise interference.

论文首先概述国内外声学诊断研究进展与盲分离研究进展，给出机器噪声声场与盲分离的数学描述，讨论了声振辐射、声全息、盲分离模型、盲分离可解性、盲分离结果不确定性、分离算法等基本问题，在此基础上，论文的研究工作分为以下四个部分：第一部分研究适用于声学特征分离的盲分离算法，提出基于特征提取的联合近似对角化盲分离算法，该算法以频谱特征或时频特征作为分离目标，从混合信号中分离源信号频谱特征或时频特征，最大限度地保留了与声学特征提取有关的频谱特征或时频特征，采用模型变换把卷积混合模型变换为一个高维瞬时混合模型，通过联合近似分块对角化算法实现源信号频谱特征与时频特征的盲反卷积。

The crystal structures have been determined by X-ray diffraction method, which show that the new complex [Co2-Co(2)(0H2)s] belongs to the bridging binuclear complex and the system of monoclinic with space group P211~,unit cell parameters a8.3850(10)A, b=27.386(4) A, c=9.610(2) A,~=98.280(10)~,V=2 183.8(6) A3 , Z=4, Dc=l.746Mg/m3,~i =l.597mm, F(000)=1168, Final R=O.0253 and wR=O.0610 S1.009 ,The two Co2~ are in distorted octahedrons. The part of [2Co] possess an approximate D2d symmetry, while the part of [OCo(2)(0H2)5] has an approximate C2 symmetry.

结构分析表明配合物(1)[Co1，(DPC2-Co(2)(OH2)5]是一个未见报导的桥联双核配合物，属单斜晶系，空间群为P2_1／c，晶胞参数：a=8.3850(10)A，b=27.386(4)A，c=9.610(2)A，β=98.280(10)A，V=2183.8(6)A~3，Dc=1.746Mg／m3，Z=4，μ=1.597mm-1，F(000)=1168，结构偏离因子R=0.0253和ωR=0.0610，吻合因子S=1.009，Co_(1)和Co_(2)的配位多面体皆为扭曲正八面体，[_2Co_(1)]部分具有近似D_(2d)对称性，[OCo(2)(OH_2)5]部分具有近似C_2对称性。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。