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211.
Data aggregation technology reduces traffic overhead of wireless sensor network and extends effective working time of the network,yet continued operation of wireless sensor networks increases the probability of aggregation nodes being captured and probability of aggregated data being tampered.Thus it will seriously affect the security performance of the network.For network security issues,a stateful public key based SDAM (secure data aggregation model) is proposed for wireless sensor networks (WSNs),which employs a new stateful public key encryption to provide efficient end-to-end security.Moreover,the security aggregation model will not impose any bound on the aggregation function property,so as to realize the low cost and high security level at the same time. 相似文献
212.
Shuichi Kawashima Chi‐Kun Lin Jun‐ichi Segata 《Mathematical Methods in the Applied Sciences》2012,35(2):125-133
We consider the initial value problem for some nonlinear hyperbolic‐dispersive systems in one space dimension. Combining the classical energy method and the smoothing estimates for the Airy equation, we guarantee the time local well‐posedness for this system. We also discuss the extension of our results to more general hyperbolic‐dispersive system. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
213.
将随机删失非参数固定设计回归模型转化为非参数回归模型进行研究;然后对此模型作了局部影响分析,得到计算影响矩阵及最大影响曲率方向的简洁公式;最后通过实例分析,验证了分析方法的有效性. 相似文献
214.
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216.
We capitalize upon the known relationship between pairs of orthogonal and minimal residual methods (or, biorthogonal and quasi-minimal residual methods) in order to estimate how much smaller the residuals or quasi-residuals of the minimizing methods can be compared to those of the corresponding Galerkin or Petrov–Galerkin method. Examples of such pairs are the conjugate gradient (CG) and the conjugate residual (CR) methods, the full orthogonalization method (FOM) and the generalized minimal residual (GMRES) method, the CGNE and BiCG versions of applying CG to the normal equations, as well as the biconjugate gradient (BiCG) and the quasi-minimal residual (QMR) methods. Also the pairs consisting of the (bi)conjugate gradient squared (CGS) and the transpose-free QMR (TFQMR) methods can be added to this list if the residuals at half-steps are included, and further examples can be created easily.The analysis is more generally applicable to the minimal residual (MR) and quasi-minimal residual (QMR) smoothing processes, which are known to provide the transition from the results of the first method of such a pair to those of the second one. By an interpretation of these smoothing processes in coordinate space we deepen the understanding of some of the underlying relationships and introduce a unifying framework for minimal residual and quasi-minimal residual smoothing. This framework includes the general notion of QMR-type methods. 相似文献
217.
我国汽车保有量预测方法浅析 总被引:4,自引:0,他引:4
对影响我国汽车市场的主要因素进行了分析,建立了以指数平滑、多元回归、神经网络为基础的汽车保有量预测模型,并对三种模型的适用性作了简单分析. 相似文献
218.
The velocity data obtained by many 3D measurement methods such as particle tracking velocimetry (PTV) are not regularly distributed
in3D space. We revised three numerical schemes to interpolate the scattered velocity vectors to a regularly spaced grid. Additionally,
two techniques were examined to smooth the resulting flow field. The different algorithms were tested for a synthetic data
set based on the analytical solution of Burgers' vortex. To study the impact of measurement errors a Gaussian noise was superimposed
on the exact solution. It was found that an interpolation scheme of higher order does not necessarily perform better than
one of lower order. The most‘robust’ algorithm was used to process 3D PTV data, which were obtained from measurements of a
separating flow in a forward facing step configuration. Information on the 3D streamlines and vortex structures was obtained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
219.
Noise reduction in Raman spectra: Finite impulse response filtration versus Savitzky–Golay smoothing
Application of the finite impulse response (FIR) filtration technique for the removal of spectral noise and background broadband deformations from the Raman spectra is tested. Optimal parameters of FIR filters are found and their effectiveness is compared with the Savitzky–Golay (SG) smoothing procedure. The FIR filtration is found to be an effective procedure to treat the whole Raman spectra, but high computing power is needed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
220.
井间层析成像的平滑SIRT算法 总被引:1,自引:0,他引:1
井间层析成像是一个非线性反演问题 ,为了保证反演过程的稳定性 ,并提高迭代的收敛速度 ,对常规的SIRT算法进行了改进 ,即引入了平滑算子对梯度场进行动态平滑 ,并且通过线性搜索确定速度更新的步长。将这种改进的算法称为平滑SIRT算法。模型试算的结果证明 ,该方法提高了迭代的收敛速度 ,而且反演结果不受初始模型的影响 ,使反演过程的稳定性大大提高 相似文献