二维的

Then, we discuss a robust implementation of the pilot-symbol-aided estimator that is insensive to channel statistics. The analysis of these algorithms is made by computer simulation. Finally, combinating with the application of channel estimation , we present two techniques: STBC (space-time block coding) and STTC (space-time trellis coding) to improve the performance of channel parameter estimation.

在基于导频的估计中，研究了基于MMSE下二维导频辅助信道估计，并结合无线信道的统计特性在一般不可知的条件下，给出了一种对无线信道的统计特性不是很敏感的鲁棒的二维导频辅助信道估计器，通过实验仿真证明其有效性。

A two dimensional fuzzy controller was designed to keep the interelectrode gap at a stable and low value, the inputs of controller were the current error and the change of current error which was transferd from the error of interelectrode gap.

设计了一个二维模糊控制器，以进给速度的增量为模糊控制器输出，将间隙的误差转化为电流的误差及误差的变化，以此作为模糊控制器的二维输入向量，使加工维持在稳定的小间隙状态。

Then we have compared the directional characteristic of the basic wavelets; according to the property of impulse function, we have simplified the formula of inverse transformation.

针对二维信号处理中的波场分离，引入了方向性小波的概念，将其用于信号波场分离，对比了三种基本小波的方向特性；根据函数的性质，提出更为简单的二维连续小波反变换公式。

With the ever-increasing needs of high power diode laser source, it is important to obtain symmetric diode laser beam with high power so that a kind of beam-shaping technique with isosceles right-angled prism group has been used to achieve this aim.

随着半导体激光器应用的日益广泛，半导体激光的光束质量在二维方向极不均衡的特点限制了它的应用范围。采用一种等腰直角棱镜组的整形方法，可实现二维方向的光束质量均匀化。

In light of the convergence theorem obtained in Chapter 2, a result on topology preservation of 2-dimensional SOM algorithm with continuous inputs is given. In Chapter 4, an equivalence relation on n dimensional Euclidean space, called equi-action relation, is introduced and a number of properties on this relation are studied.

指出了已有的有关SOM算法拓扑保序定义的缺陷，并在此基础上，给出了一个具有连续输入的二维SOM算法的拓扑保序新定义；利用第二章中的收敛性定理，我们进而获得了一个具有连续输入的二维SOM算法的拓扑保序性定理。

Then based on the results, the characteristics of radar stealth of a naval vessel were analyzed.

建立以某舰船为参照的艏向与正横向的近似二维模型，基于二维时域有限差分法计算舰船的艏向与正横向在不同频率入射波情况下的雷达散射截面，并根据计算结果对某舰船的雷达隐身特性进行分析。

It was proved that the area coordinates of plane triangle element and the volume coordinates of tetrahedron element are equivalent to the oblique Cartesian coordinates by the analytical and geometrical methods.

本文通过分析法和几何法证明：在有限元法和边界元法中，平面三角形单元的面积坐标或四面体单元的体积坐标与由这些单元的二边或三边构成的斜交笛卡儿二维坐标或三维坐标，尽管定义不同，而其内容却是完全对等的。

Based on the array signal processing and the eigenstructure decomposition method, the signal subspace and the noise subspace are achieved by reconstructing and decomposing the data matrix collected by the array sensors. By using the orthogonal properties of the two subspaces, the information about the velocities and bearings of spatial moving targets can be exactly obtained.

本文提出一种超分辨的二维谱估计方法，它利用的是阵列处理技术，对天线接收数据进行本征分析，将信号数据张成一个空间并对其进行分解，根据正交原理分割成信号子空间和噪声子空间，构造出噪声本征矢量，利用信号子空间与噪声子空间的正交性，在空间谱上形成极值点，从而达到对方向和速度的二维高分辨率估计。

A revised plane wave expansion method for calculating the band structure of photonic crystals is presented.

采用一种改进的平面波展开法，运用一种有效的设计二维各向异性光子晶体的方法，在低频和高频区域内获得了具有较大禁带的两种二维光子晶体。

Methods:43 patients including 10 with mitral stenosis associated aortic regurgitation, 12 with mixed mitral valve lesions and 21 with mixed mitral valve lesions and combined with aortic regurgitation were studied.MVA determinded by (1) two -dimensional echocardiography with a cross-sectional area in the short-axis view (2DE),(2) pressure half-time using formula of 220/PHT,(3) color Doppler flow imaging with a jet cross-sectional area in the short-axis view with planimetry,(4) CDFI with a color jet width at the mitral valve orifice in the apical four-chamber view and long-axis view, assuming an elliptic mitral orifice, compared with the orifice area of excised mitral valve during mitral valve replacement.

材料与方法∶分别用二维超声(2DE)、压差减半时间、彩色多普勒二尖瓣口血流截面积和椭圆形面积法测定43例风湿性心脏病二尖瓣狭窄拟行人工瓣置换术患者的MVA，其中合并主动脉瓣反流 10例，合并二尖瓣反流 12例， 21例，并与手术标本的实测面积相比较。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。