校正集选择方法对于积雪草总苷中积雪草苷NIR定量模型的影响

近红外光谱定量分析中,采用合适的校正集选择方法是建立预测性能良好的近红外定量模型的关键技术之一。校正集选择方法有RS法、CS法、KS法和SPXY法等,但是对以上校正集选择方法缺乏系统地比较。本文以积雪草总苷中积雪草苷NIR定量模型为载体,对NIR定量模型的7个评价指标进行分类和筛选,比较了CS法、KS法和SPXY法三种校正集选择方法对NIR定量模型的准确性和稳健性两类评价指标的影响。结果表明,SPXY法与CS法、KS法选择校正集样本后所建近红外模型的RPD和RSEP两个准确性评价指标存在显著性差异,模型的稳健性评价指标RMSECV和|RMSEP-RMSEC|不存在显著性差异。因此,建立积雪草总苷近红外光谱的积雪草苷偏最小二乘定量模型时,SPXY校正集选择方法能显著提高该定量模型的预测准确度,但对模型稳健性的评价指标没有显著影响,以上结论为中药固体体系建立近红外定量模型确定校正集选择方法提供参考。     

基于DPDV算法的二元光学元件设计

为解决用于高斯分布激光束整形的二元光学元件设计问题 ,在深入研究现有的各种迭代算法 ,如GS算法、模拟退火法、Alopex法等的基础上 ,提出了并行模拟退火算法和DPDV算法 (DifferentParametertoDifferentVariables)。特别是DPDV算法综合了各种算法的优点 ,而避开了其缺点。得到了迄今为止最好的计算结果     

一种基于DSP的红外图像防空导弹检测与跟踪方法

提出一种基于DSP的红外图像防空导弹检测与跟踪算法,算法分为导弹飞行锥形尾烟跟踪和发动机脱落导弹跟踪2个阶段。其中,采用基于轮廓近似曲率表示算法跟踪带有尾烟的导弹,采用基于区域生长的小目标跟踪算法跟踪发动机分离后的燃烧弹标。文章中提出的算法在基于C6416DSP平台中实现,多次外场实验结果表明:该算法能够实时稳定地实现防空导弹光电跟踪制导。     

Entropy-Based Approach in Selection Exact String-Matching Algorithms

The string-matching paradigm is applied in every computer science and science branch in general. The existence of a plethora of string-matching algorithms makes it hard to choose the best one for any particular case. Expressing, measuring, and testing algorithm efficiency is a challenging task with many potential pitfalls. Algorithm efficiency can be measured based on the usage of different resources. In software engineering, algorithmic productivity is a property of an algorithm execution identified with the computational resources the algorithm consumes. Resource usage in algorithm execution could be determined, and for maximum efficiency, the goal is to minimize resource usage. Guided by the fact that standard measures of algorithm efficiency, such as execution time, directly depend on the number of executed actions. Without touching the problematics of computer power consumption or memory, which also depends on the algorithm type and the techniques used in algorithm development, we have developed a methodology which enables the researchers to choose an efficient algorithm for a specific domain. String searching algorithms efficiency is usually observed independently from the domain texts being searched. This research paper aims to present the idea that algorithm efficiency depends on the properties of searched string and properties of the texts being searched, accompanied by the theoretical analysis of the proposed approach. In the proposed methodology, algorithm efficiency is expressed through character comparison count metrics. The character comparison count metrics is a formal quantitative measure independent of algorithm implementation subtleties and computer platform differences. The model is developed for a particular problem domain by using appropriate domain data (patterns and texts) and provides for a specific domain the ranking of algorithms according to the patterns’ entropy. The proposed approach is limited to on-line exact string-matching problems based on information entropy for a search pattern. Meticulous empirical testing depicts the methodology implementation and purports soundness of the methodology.     

故障诊断算法在MapReduce中的优化实现

针对故障诊断算法特点,给出了MapReduce框架实现故障诊断算法的基本方法。通过对故障诊断算法和MapReduce运算框架的分析,得出诊断算法MapReduce化的基本方法和思路。在算法研究的基础上,针对非迭代诊断算法,采用传统MapReduce框架实现。针对迭代诊断算法,采用添加了传送模块的迭代式MapReduce框架实现。分别以最近邻法和模糊C均值聚类算法为例,给出非迭代和迭代诊断算法MapReduce化的具体实现。实验结果表明,本文所提基本方法可以运用在故障诊断算法中,为诊断算法MapReduce化提供依据,将MapReduce运用到故障诊断算法中可以有效提升故障诊断效率。     

圆目标定位连续阈值质心算法研究

以DSP平台圆目标定位为研究对象,提出了连续阈值质心算法,利用算术平均原理对普通质心法进行了改进。结果表明,该算法减小了随机误差和系统误差。存在噪声的情况下,其定位精度能达到0.02～0.05pixels,同等情况下与普通质心法相比较,精度提高了4～10倍,抗噪声能力更强,而计算量却没有增加,能够用于DSP平台的圆目标快速精确定位。     

采用听觉滤波器的宽带MUSIC声源定位方法

在分析了采用短时傅里叶变换的宽带MUSIC声源定位算法(SF-MUSIC)存在问题的基础上,提出了一种采用听觉滤波器的宽带MUSIC声源定位算法(AF-MUSIC)。该算法使用听觉滤波器组对传声器阵列接收到的信号进行不等带宽分解后,在各个频率通道上使用MUSIC算法进行声源定位,并结合子区间频数估计法得出最终定位结果。对算法进行的实验评估表明,在不同声源类型条件下,相比SF-MUSIC算法,AF-MUSIC算法的平均估计误差减少2.5479°,有效地提高了声源波达方向估计的精度。      

Cognitive radio resource allocation based on coupled chaotic genetic algorithm

A coupled chaotic genetic algorithm for cognitive radio resource allocation which is based on genetic algorithm and coupled Logistic map is proposed.A fitness function for cognitive radio resource allocation is provided.Simulations are conducted for cognitive radio resource allocation by using the coupled chaotic genetic algorithm,simple genetic algorithm and dynamic allocation algorithm respectively.The simulation results show that,compared with simple genetic and dynamic allocation algorithm,coupled chaotic genetic algorithm reduces the total transmission power and bit error rate in cognitive radio system,and has faster convergence speed.     

利用环形子孔径哈特曼-夏克斜率数据复原全孔径波前相位算法研究

提出了一种适用于哈特曼-夏克波前传感器的环形子孔径拼接检测技术的拼接复原算法.该算法通过建立各个环形子孔径内有效的哈特曼-夏克斜率数据和全孔径波前相位的关系,避免了环形子孔径区域的波前复原过程,从而有效地解决了环形子孔径区域的哈特曼-夏克波前传感器有效采样率低的问题.算法对斜率测量噪声较不敏感,具有较好的抗噪声干扰的能...     

改进的正交匹配追踪的语音增强算法*

为了提高传统正交匹配追踪（Orthogonal Matching Pursuit,OMP ）算法的语音增强性能和运算速度,本研究基于稀疏编码理论,提出了一种改进的OMP算法的语音增强算法。其一,将K-奇异值分解（K-singular value decomposition,K-SVD）算法与OMP算法相结合,通过设置能量阈值的方法,提高OMP算法的语音增强性能;其二,通过改进传统OMP算法中信号稀疏逼近的计算方法,提高算法的运算速度。改进的OMP算法的语音增强算法与传统K-SVD语音增强算法相比,采用PESQ评价增强语音的质量,NCM评价语音的可懂度。在NCM的值基本保持不变的情况下,PESQ的值平均提高约12.47%,取得了更好的增强效果。取得了更好的增强效果。改进的OMP算法的运算速度与传统OMP算法相比提高近一倍。     

IDeC(k): A new velocity reconstruction algorithm on arbitrarily polygonal staggered meshes

We propose a novel algorithm for velocity reconstruction from staggered data on arbitrary polygonal staggered meshes. The formulation of the new algorithm is based on a constant polynomial reconstruction approach in conjunction with an iterative defect correction method and is referred to as the IDeC(k) reconstruction. The algorithm is designed for second order accuracy of the reconstructed velocity field and also leads to a consistent estimate of velocity gradients. Accuracy, convergence and robustness of the new algorithm are studied on different mesh topologies and the need for higher-order reconstruction is demonstrated. Numerical experiments for several cases including incompressible viscous flows establish the IDeC(k) reconstruction as a generic, fast, robust and higher-order accurate algorithm on arbitrary polygonal meshes.     

高功率微波效应的多层次多物理场协同算法

针对半导体器件、电路、电子系统的高功率微波效应,提出了一套全新的多层次多物理场协同计算方法。该算法基于半导体器件的物理结构模型,联立并求解由电磁场、半导体物理和热力学方程构成的多物理场方程组,实现了器件级高功率微波效应的仿真;通过器件多物理场仿真和电路仿真的协同计算完成电路级效应仿真;最后进行电路效应和电磁环境的协同计算,获取由多个电路、外壳封装、孔缝和线缆等组成的电子系统的高功率微波效应数据。介绍了该算法的原理和流程,以商业PIN二极管为例,计算了该器件及组成限幅器电路的温度效应、正向恢复特性、半封闭腔体内空间微波辐射等效应,通过与实验测试的对比验证了算法的正确性,同时对效应现象给出了物理机理解释。     

一种用于多叶准直器适形放疗的剂量算法研究

描述了一种用于多叶准直器适形放疗的剂量计算方法。 在不同大小的方野和非规则野照射情况下, 将此方法得到的剂量分布与微分卷积法计算得到的剂量分布进行了精度验证。 结果表明, 这种算法具有较高的剂量精度和较快的计算速度, 因此可在适形放疗中用作MLC适形野的自动生成。 A dose calculation algorithm for MLC based conformal radiotherapy is described in this paper. The algorithm is formulated by the coordinate of MLC leaves. Verification on the algorithm is made by comparing the dose distributions generated by this algorithm with that generated by a Differential Convolution Superposition algorithm for various regular and irregular fields. The results demonstrate that the present algorithm has suitable accuracy and high computational efficiency, thus it could be useful for the treatment planning process in MLC based conformal radiotherapy, where the workload for interactively or automatically designing the shapes of MLC is heavy.     

An efficient algorithm used for full-field optical coherence tomography

An efficient algorithm for computing optical coherence tomography is presented, which is based on the discrete differences of a time/depth sequence of interferograms. The existing multiple-step phase-shift algorithms, including those solved from Carré and Hariharan equations as well as circular-step algorithm proposed by Dubois et al., are analyzed and compared with the proposed algorithm. The analytical and experimental results show the computational efficiency of the new algorithm outperforms others. The simulations also demonstrate that the algorithm based on derivatives of four phase-shifted images is less sensitive to the phase-shift noise comparing to traditional 4-step phase-shift-based algorithm.     

The block Schur algorithm for designing optical multi-layered structures

We present how to use the block Schur algorithm to design optical multi-layered filters. The block Schur algorithm can, in turn, be applied to find reflection coefficients of optical multi-layered filters. We show that the block Schur algorithm using the block matrices is faster than the standard Schur algorithm using the scalar elements on vector processor. The optimum sub-matrix size for the block Schur algorithm on CRAY Y-MP C98 supercomputer is also suggested.     

改进的变步长自适应最小均方算法及其数字信号处理

针对紫外光通信中传统自适应最小均方(LMS)算法存在的不足,提出了一种新的变步长LMS(VSS-LMS)算法,利用MATLAB仿真验证了该算法的可行性,以TMS320VC5509为核心设计了数字信号处理(DSP)最小化硬件系统和VSS-LMS算法的软件流程,在硬件上实现了传统LMS算法和新的VSS-LMS算法的自适应滤波,并进行了对比分析,结果表明所提出的VSS-LMS算法具有较快的收敛速度和较小的稳态误差,这对紫外光通信接收系统的设计和优化具有一定的参考意义。     

一种基于约束共轭梯度的闪光照相图像重建算法

 针对闪光照相系统成像信噪比低的特点,提出了正则化预优约束共轭梯度算法（RPCCG）。RPCCG算法在闪光照相重建方程中引入Tikhonov正则化准则,利用预优约束共轭梯度法迭代求图像重建的最优解。数值试验表明,采用最小二乘+平滑准则的RPCCG算法是一种具有较高的抗噪能力的有效闪光照相图像重建算法,具有良好的收敛性和稳定性以及较高的重建精度。     

Improving performance of FxRLS algorithm for active noise control of impulsive noise

Active noise control (ANC) systems employing adaptive filters suffer from stability issues in the presence of impulsive noise. New impulsive noise control algorithms based on filtered-x recursive least square (FxRLS) algorithm are presented. The FxRLS algorithm gives better convergence than the filtered-x least mean square (FxLMS) algorithm and its variants but lacks robustness in the presence of high impulsive noise. In order to improve the robustness of FxRLS algorithm for ANC of impulsive noise, two modifications are suggested. First proposed modification clips the reference and error signals while, the second modification incorporates energy of the error signal in the gain of FxRLS (MGFxRLS) algorithm. The results demonstrate improved stability and robustness of proposed modifications in the FxRLS algorithm. However, another limitation associated with the FxRLS algorithm is its computationally complex nature. In order to reduce the computational load, a hybrid algorithm based on proposed MGFxRLS and normalized step size FxLMS (NSS-FXLMS) is also developed in this paper. The proposed hybrid algorithm combines the stability of NSS-FxLMS algorithm with the fast convergence speed of the proposed MGFxRLS algorithm. The results of the proposed hybrid algorithm prove that its convergence speed is faster than that of NSS-FxLMS algorithm with computational complexity lesser than that of FxRLS algorithm.     

An algorithm for the localization of multiple interfering sperm whales using multi-sensor time difference of arrival

In this paper an algorithm is described for the localization of individual sperm whales in situations where several near-by animals are simultaneously vocalizing. The algorithm operates on time-difference of arrival (TDOA) measurements observed at sensor pairs and assumes no prior knowledge of the TDOA-whale associations. In other words, it solves the problem of associating TDOAs to whales. The algorithm is able to resolve association disputes where a given TDOA measurement may fit to more than one position estimate and can handle spurious TDOAs. The algorithm also provides estimates of Cramer-Rao lower bound for the position estimates. The algorithm was tested with real data using TDOA estimates obtained by cross-correlating click-trains. The click-trains were generated by a separate algorithm that operated independently on each sensor to produce click-trains corresponding to a given whale and to reject click-trains from reflected propagation paths.     

二维泊松方程的遗传PSOR改进算法

针对二维泊松方程在实际应用过程中几种常用方法存在计算量大、易发散、局部收敛等不足,提出了一种改进算法.该算法基于并行超松弛迭代法,采用遗传算法对松弛因子进行全局寻优,解决了超松弛迭代法求解泊松方程时最佳松弛因子难以确定的问题.构建了多目标适应度函数,优化了遗传算子参数,分析了算法的计算量、计算时间与误差精度,与传统方法进行了对比研究.结果表明:松弛因子对泊松方程求解的速度与精度影响显著;改进算法能减少迭代次数,节省计算时间,加快方程的求解;算法适合于求解计算量较大、精度要求较高的时域有限差分方程,而且精度要求越高,算法的性能越好,节省的时间也越多.