共查询到20条相似文献，搜索用时 797 毫秒
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基于正交表的准均匀设计 总被引：1，自引：0，他引：1
给出了利用正交表经过适当的几体旋转变换构造准均匀设计表的方法，准均匀设计基本上保持了正交设计的均匀分散和整齐可比性，而且每个因素的每个水平只做一次试验，因而特别适合地多水平的试验设计。 相似文献
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提出一种结合嵌入式技术的三维人脸门襟系统的设计及具体实现方法。通过搭建相应硬件配准、运用正交小波技术,配合双目立体视觉原理,完成人脸的三维采集和特征识别。该系统因为加入了三维的因素,可以有效地克服传统的门襟系统受到光照、角度等外界因素影响带来的弊端。实验表明,该方法能够建立真实有效的三维人脸模型,提高了门禁系统识别的准确性。 相似文献
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对天然气长输管道进行经济评价进而优选出合理的输气管道设计方案是管线设计的一项重要工作。对输气管道进行优化设计主要是确定技术先进且经济合理的技术经济参数,从而降低系统的综合费用和提高投入产出比,最终提高经济效益。正交试验设计法是统计数学的重要分支。它可以减少试验次数,缩短试验周期,迅速得到优化方案。本文就是基于正交试验法对天然气长输管道经济评价影响因素进行研究。通过计算分析得到了各个影响因素对输气管道综合费用的影响程度,可知：在输气管道综合费用的四个影响因素中,管径的影响最大,首站压比的影响最小。 相似文献
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用正交设计方法求解非线性规划的区间约束最优化问题 总被引：1，自引：0，他引：1
给出了以正交设计原理为基础的两种方法———正交表法和加点正交表法,求解非线性规划的区间约束最优化问题。方法不要求目标函数可导,不依赖于初始点,计算速度快,算法简单,容易编成程序在计算机上执行。用检验考题对算法进行了验证,并进行了分析和探讨 相似文献
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正交矩阵是非常重要的,一个矩阵要正交化,通常采用的是施密特(Schmid)t正交化的方法,本文将介绍一种新的矩阵正交化的方法,而且比原来的方法简单快捷。 相似文献
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Xiaowei Jiang Xiangyong Chen Junwei Hu Huaicheng Yan Mingfeng Ge 《Journal of The Franklin Institute》2019,356(6):3353-3367
In this paper, the achievable tracking performance limitations of discrete-time, multi-input multi-output (MIMO) networked control systems (NCSs) are studied. The channel is modeled as an additive white Gaussian noise and signal-to-noise ratio (SNR) limited channel with feedback. Under this framework, the closed relationships among stabilization, tracking performance, and SNR limited are quantitatively revealed. Some new results a.erived according to the allpass factorization and Youla parameterization of two degrees of freedom controller. The results show that the best tracking performance is in connection with the unstable poles, non-minimum phase zeros of the system. It is also demonstrated that the tracking performance will be badly degraded by feedback channel noise and due to the SNR limited. Finally, a simulation example is presented to validate the conclusions. 相似文献
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Antonio Mauricio F.L. Miranda de Sá 《Journal of The Franklin Institute》2006,343(7):688-698
Coherence plays a very important role in linear systems analysis, since, in addition to quantify the similarity between signals, it is related to other quantities of interest, such as the signal-to-noise ratio (SNR). The sampling distribution of coherence estimates between Gaussian signals is well established, and hence, in this particular case, the statistics of SNR can be readily found if it is calculated from coherence estimates. However, in some applications, one of the signals is periodic, leading to a different coherence sampling distribution, which has been recently investigated. This work aims at developing analytical expressions for bias, variance and the probability density function of coherence-based SNR estimates under this particular assumption. Routines for obtaining this latter as well as critical values of the estimates are also provided. 相似文献
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在数字通信中，信道的多径传播和衰落特性常在接收端引起码间干扰（ISI）并降低信噪比，严重影响了通信质量。本文研究了空间分集与盲均衡相结合的空间分集均衡技术（SDE），提出了一种基于等增益合并和判决反馈盲均衡的空间分集均衡算法，以克服码间干扰并消除衰落对通信系统所带来的不利影响。通过计算机仿真对空间分集均衡算法和传统盲均衡算法的性能进行了对比，结果表明空间分集均衡技术优于传统的盲均衡技术，提高了数字通信性能。 相似文献
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The role of potential-well depth and width on stochastic resonance (SR) driven by colored noise with different noise correlation times is explored and evaluated by deriving the analytic expression of output signal-to-noise ratio (SNR) as a most widely used indicator for quantifying SR phenomenon. Double resonance peaks are observed and shifted between single peak and double peaks when SNR is expressed as the function of varying potential-well depth, varying potential-well width, additive noise intensity, multiplicative noise intensity and the intensity ratio between two noise, respectively. Moreover, the SR behavior induced by varying potential-well depth is different from that induced by varying potential-well width. Even the shapes of SNR curves under different correlation times and coupling strength for potential-well depth are opposite to those for potential-well width and furthermore they are also of dependence on initial conditions. Above clues may be helpful to the precise control of SR by varying potential-well depth and width separately for weak signal enhancement. 相似文献
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一种基于子波变换的语音增强方法 总被引：1，自引：0，他引：1
在分析了随机噪声的子波变换系数在不同尺度上的传递特性和噪声信号奇异性与子波模极大值的关系后,提出了用一尺度间变化的门限阈值来抑制带噪训音信号在不同尺度上噪声子波系数,从而实现了在重构信号中消除噪声的目的。文中还给出了不同信噪比语音信号的子波去噪的计算机仿真结果,从结果上看出,本文的方法有较好的语音去噪、增强效果。 相似文献
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In this paper, a study on the end-to-end performance of dual-hop non-regenerative relaying over independent generalized-K (KG) fading channels is presented. Using a suitable upper bound for the end-to-end signal-to-noise ratio (SNR), novel closed-form expressions for the cumulative distribution function (CDF), probability density function (PDF) and the moments of this bounded SNR are derived. These results can be afterwards used to obtain important performance metrics of the considered system such as the outage probability and the error performance of digital modulation schemes. In the case of independent but non-necessarily identical fading channels, lower bounds for the average bit error probability (ABEP) for different modulation schemes are determined by using the Padé approximants method. For the case of identical fading channels, closed-form lower bounds for the ABEP are derived. Various numerical and computer simulation results illustrate the proposed analysis. 相似文献
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提出一种基于遗传算法优化BP网络结构的自适应噪声抵消器，BP算法是最典型的多层神经网络学习算法，它在局部搜索时比较成功．但由于BP网络大多采用沿梯度下降方向的搜索算法，因而不可避免地存在收敛速度慢，容易陷入局部极小点等问题。而遗传算法擅于全局搜索，鲁棒性很强，将采用遗传算法优化网络初始权值的方法，将两种算法相结合，做到优势互补。GA与BP算法的混合算法不论是在运行速度还是在运算精度上都较单纯的BP算法有提高，在信噪比的改善程度上，混合算法的信噪比针对余弦信号提高了23db左右。 相似文献
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小波双线性插值应用于光学遥感图像 总被引：8，自引：0，他引：8
针对遥感图像插值要求,尽可能保持原图像信息,提高图像分辨率,并适合人眼观察的特点,提出适合于遥感图像的小波双线性插值方法.实验表明,与双线性插值相比,该算法得到较高的信噪比和较好的图像效果. 相似文献
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提出一种分析中继选择反馈错误影响的方法,给出反馈错误与目的节点接收信噪比的近似表达式.基于该表达式,给出数据传输和信息反馈2个阶段的功率分配方案,以最大化数据传输速率的上界.仿真结果显示,所提功率分配方案能够有效提高数据传输速率,且表明有噪反馈下中继数量受到限制. 相似文献
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针对原SPIHT算法存在扫描的重复且未能充分利用小波系数分布特点,随着压缩比的增加,会引起编码效率的下降等不足,提出一种改进的图像压缩编码算法。改进的图像编码算法低频子带进行DPCM无损编码,高频子带采用优化排序的SPIHT算法。仿真结果表明,改进算法较原算法在重构图像的主观效果和峰值信噪比上都得到了提高。 相似文献