二元三角插值多项式的收敛阶

构造了一个二元组合型三角插值多项式算子,使该算子对任意的关于变量ｘ、ｙ均以２π为周期的连续函数ｆ（ｘ,ｙ）都能在全平面上一致地逼近,且具有最佳收敛阶。     

Signal transformation and interpolation based on modified DCT synthesis

This paper proposes a novel signal transformation and interpolation approach based on the modification of DCT (Discrete Cosine Transform). The proposed algorithm can be applied to any periodic or quasi periodic waveform for time scale and/or pitch modification purposes in addition to signal reconstruction, compression, coding and packet lost concealment. The proposed algorithm has two advantages:

• (i) 

  Since DCT does not have the explicit phase information, one does not need the cubic spline interpolation of the phase component of the sinusoidal model.

• (ii) 

  The parameters to be interpolated can be reduced because of the energy packing efficiency of the DCT. This is particularly important if signal synthesis is carried out on a remote location from the transmitted parameters.

The results are presented on periodic waveforms and on speech signal in order to appreciate the fidelity of the proposed algorithm. In addition, the proposed method is compared with TD-PSOLA, sinusoidal model and phase vocoder algorithms. The results are presented in objective PESQ scores for time scale modification and output files are provided as supplementary material,¹ for subjective evaluation, for packet lost concealment. Results prove that the proposed modification of the DCT synthesis provides a favorable algorithm for specialists working in the signal processing area.     

Efficient analysis of wireless communication antennas using an accurate [Z] matrix interpolation technique

An accurate impedance matrix interpolation technique based on the surface integral equation (SIE) is presented for the analysis of wireless communication antennas over wide frequency bands. The first‐order derivative of the impedance matrix at the internal frequency is considered in the cubic polynomial‐based interpolation scheme, thus the novel impedance matrix interpolation scheme will provide high accuracy and high efficiency over a frequency band. To demonstrate the efficiency and accuracy of the proposed method, numerical results for planar inverted F antennas (PIFA) and a wideband E‐shaped patch antenna are presented. Good agreement among the interpolation results, exact MoM solutions, finite element method (FEM) solutions, and measured data is observed over the bandwidth. Besides, dimensions of the feeding probe are also studied to investigate their effect on the input impedance and radiation patterns. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Toric forms of elliptic curves and their arithmetic

We scan a large class of one-parameter families of elliptic curves for efficient arithmetic. The construction of the class is inspired by toric geometry, which provides a natural framework for the study of various forms of elliptic curves. The class both encompasses many prominent known forms and includes thousands of new forms. A powerful algorithm is described that automatically computes the most compact group operation formulas for any parameterized family of elliptic curves. The generality of this algorithm is further illustrated by computing uniform addition formulas and formulas for generalized Montgomery arithmetic.     

血液粘度仪旋转锥体角速度误差分析与补偿

剪切池内旋转锥体的角速度是新型锥板式血液粘度仪的主要信息源,其精度取决于光电传感器和齿形盘.分析了光电传感器的点光源特性和齿形盘的周期性摆动及其加工精度导致的角度误差.针对锥体角速度的单调递减特性、角度误差在单转内的随机性及整个测量过程中呈周期性,采用有理三次样条插值算法对角速度误差进行补偿.实验结果表明:该方法可提高...     

SimpleGrid toolkit: Enabling geosciences gateways to cyberinfrastructure

Cyberinfrastructure science and engineering gateways have become an important modality to connect science and engineering communities and cyberinfrastructure. The use of cyberinfrastructure through gateways is fundamental to the advancement of science and engineering. However, learning science gateway technologies and developing science gateways remain a significant challenge, given that science gateway technologies are still actively evolving and often include a number of sophisticated components. A geosciences gateway must be designed to accommodate legacy methods that geoscientists use in conventional computational tools. The research described in this paper establishes an open-source toolkit—SimpleGrid for learning and developing science gateways based on a service-oriented architecture using a component-based approach that allows flexible separation and integration of the components between geocomputation applications and cyberinfrastructure. The design and implementation of SimpleGrid is based on the National Science Foundation TeraGrid—a key element of the U.S. and world cyberinfrastructure. This paper illustrates our experience of using SimpleGrid and a spatial interpolation method in a tutorial to teach TeraGrid science gateways.     

基于加权ENO的图像放大算法

E.Arandiga的图像自适应插值方法在图像边界区域使用了ENO方法进行插值。通过比较差商的绝对值的大小自适应地选择模板,尽量避免所选择的模板中包含间断,有效地抑制了Gibbs振荡,但仍有很多不足。为弥补ENO方法的缺点,提高插值方法的精确度,提出基于加权ENO的图像放大方法。基本思想是将图像的离散化形式看成图像在单元网格上的平均值,先判断每个单元中是否存在图像边界,在图像边界区域使用加权ENO方法插值图像,在光滑区域使用线性平均插值。该放大方法能得到比FArandiga的图像自适应插值方法更高阶的精度。     

基于视频对象的区域分割及其应用

为适应MPEG-4基于对象的应用,提出一种基于视频对象的区域分割算法。在视频对象的指导下,利用均值漂移进行分割,性能比传统均值漂移算法在计算时间、占用内存等方面均有提高,适用于运算速度要求高和处理器资源有限的情况。将分割结果应用于区域指导的图像插值,能保证较快的处理速度和兴趣区域较好的图像质量。实验结果证明了该方法的有效性。     

基于DSP的高精度测频方法与软件设计

提出了一种基于数字信号处理器(DSP)的测频方法,用于光纤涡轮流量计转子叶片频率的测量.在简要分析了光纤涡轮流量计的工作原理的基础上,设计出了光纤涡轮流量计测量系统软件的硬件电路平台;阐述了利用事件管理器通用定时器实现高精度数据采集方法的设计与DSP实现;分析了高稳定性、实时性的FIR滤波算法与DSP实现;讨论了利用插值方法改进FFT算法实现高精度测频的DSP实现;利用通用定时器的比较操作来产生脉宽调制(PWM)波,实现TTL电平输出.