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21.
22.
正则化长波方程的三次样条差分模拟 总被引:2,自引:0,他引:2
本文对正则化长波方程(RLW方程)的时间、空间项分别采用三次样条公式进行离散,所得到的差分方程为三点、三层隐格式,对时间的精度为四阶,对空间的精度为二阶,每个时间步只需求解一个三对角方程组,而三次样条配置法在每个时间步中需要求解三个三对角方程组。本文对单个孤立波的演化进行了计算,参数与文[8]相同,其结果与解析解的最大绝对误差均保持在10~(-3)的量级以内,与文[8]给出的数值方法精度相当。对两、三个孤立波的相互碰撞,本文结果显示出在忽略10~(-3)量级的误差后,碰撞前后的孤立波形状保持不变,无论是一个孤立波的演化,还是两、三个孤立波相互碰撞,当将波形放大100倍后均可以发现有振荡的尾波,这说明这类振荡尾波的产生并非真实的物理现象,而是由数值误差产生的。本文认为仅从工程应用的意义上说,RLW方程具有孤立子性质的结论是可以接受的。 相似文献
23.
用保形样条方法求解非定常对流扩散方程 总被引:1,自引:0,他引:1
在欧拉-拉格朗日分裂方法的基础上,本文发展了一种固定网格上的欧拉-拉格朗日分裂方法.保形样条方法(SPSM)被用来解决倒特征线插值问题.通过求解几个有精确解的例子,说明SPSM方法的解是单调无振荡的,并且数值耗散也是比较小的. 相似文献
24.
The self-organizing map (SOM) [5] provides a general data approximation method which is suitable for several application domains. The topology preservation is an important feature in data-analysis and may also be advantageous for the evaluation of the data in a function approximation or regression task. For this reason the interpolated self-organizing map (I-SOM) adds an output layer to the SOM architecture which computes a real valued output vector. This paper presents an extension of I-SOM towards a continuous interpolation. It is compared to RBF and to the parametrized self-organizing map. 相似文献
25.
参数三次B样条曲线的一种整体光顺方法 总被引:7,自引:0,他引:7
本文在能量法的基础上,提出了一种新的目标函数,给出了参数三次B样条曲线的一种新的整体光顺方法。利用这种方法得到的曲线不仅具有较小的应变能,而且曲率变化比较均匀,具有很好的光顺效果。该方法能推广到对曲面的光顺。 相似文献
26.
27.
一个矢量形式的双圆弧插值算法 总被引:3,自引:1,他引:2
本文在分析数控插补最常用的双圆弧插值算法特点的基础上,将以局部坐标系中的三角运算为核心的传统双圆弧插值算法,改造成为以整体坐标系中的线性运算为核心的矢量形式的双圆弧插值算法,从而减少了计算的复杂性和程序的复杂性,提高了效率和可靠性。 相似文献
28.
Dimitrios Tzovaras Nikos Grammalidis Michael G. Strintzis 《Signal Processing: Image Communication》1998,11(3):205-230
In the present paper techniques are examined for the coding of the depth map and disparity fields for stereo or multiview image communication applications. It is assumed that both the left and right channels of the multiview image sequence are coded using block- or object-based methods. A dynamic programming algorithm is used to estimate a disparity field between each stereo image pair. Depth is then estimated and occlusions are optionally detected, based on the estimated disparity fields. Spatial interpolation techniques are examined based on the disparity/depth information and the detection of occluded regions using either stereoscopic or trinocular camera configurations. It is seen that the presence of a third camera at the transmitter site improves the estimation of disparities, the detection of occlusions and the accuracy of the resulting spatial interpolation at the receiver. Various disparity field and depth map coding techniques are then proposed and evaluated, with emphasis given to the quality of the resulting intermediate images at the receiver site. Block-based and wireframe modeling techniques are examined for the coding of isolated depth or disparity map information. Further, 2D and 3D motion compensation techniques are evaluated for the coding of sequences of depth or disparity maps. The motion fields needed may be available as a byproduct of block-based or object-based coding of the intensity images. Experimental results are given for the evaluation of the performance of the proposed coding and spatial interpolation methods. 相似文献
29.
An 8-bit, 200 MSPS Folding and Interpolating ADC 总被引:1,自引:0,他引:1
An 8-bit, 200 MSPS folding and interpolating analog-to-digitalconverter, ADC, has been implemented in a 1.2 µmBiCMOS-process. It achieves 7.5 effective bits with a power dissipationof 575mW. The active area is 4mm2. The implementationand measured results are presented. A simple analytical modelfor the interpolation-induced nonlinearity in a folding and interpolatingADC using sinusoidal folding is presented. The bowing of thereference ladder due to interaction with the input stages isanalyzed, and analytical models are derived. 相似文献
30.
The crystallization behavior of well-defined star-shaped cubic silsesquioxane-poly(ethylene oxide) (CSSQ-PEO) and linear PEO were studied in terms of differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). It was found in DSC analysis that the glass transition temperature (Tg) and the crystallization temperature (Tc) of CSSQ-PEO are different from those of linear PEO. The presence of CSSQ in PEO reduced the overall crystallization growth rate. This effect can be ascribed to the reduction of the mobility of the PEO crystallites in the presence of CSSQ and the star structure of the polymer. The Ozawa method is qualitatively satisfactory for describing the nonisothermal crystallizations of linear PEO and CSSQ-PEO. The presence of CSSQ leads to the diffusion- and nucleation-controlled mechanisms in the crystallization process of CSSQ-PEO whilst only the nucleation-controlled mechanism was observed in the case of linear PEO. The apparent activation energy required for crystallization was calculated using the Kissinger method. The isothermal crystallization morphology of PEO and CSSQ-PEO were also examined by cross-polarizing optical microscopy (CPOM). The CPOM images indicated the spherulite growth is slower in CSSQ-PEO as compared to linear PEO. It was also investigated that more number of PEO spherulites in CSSQ-PEO were observed, which sizes are markedly smaller than the spherulites developed in linear PEO. Wide-angle X-ray scattering (WAXS) studies showed that the crystallization peaks for linear PEO and CSSQ-PEO appeared at different temperature revealing the crystallization process and crystal growth rate are different from each other. However, no significant distortion of the crystal structure of PEO was evaluated in the presence of CSSQ. 相似文献