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一种优化的舰船噪声连续谱特征提取算法研究 被引量:1
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作者 姚运启 张效民 赵延安 《计算机仿真》 CSCD 北大核心 2011年第5期5-8,共4页
研究舰船辐射噪声,是目标识别的依据。连续谱是水下目标检测和识别的重要判别特征,为在目标出现后最短时间完成判决,要对相应目标特征参数进行提取,提出了更高的时效性,并能实时快速提取。针对传统算法运算周期长和段连接处有毛刺的干... 研究舰船辐射噪声,是目标识别的依据。连续谱是水下目标检测和识别的重要判别特征,为在目标出现后最短时间完成判决,要对相应目标特征参数进行提取,提出了更高的时效性,并能实时快速提取。针对传统算法运算周期长和段连接处有毛刺的干扰问题,采用一种快速且有效算法。用分段和固定拟合频率的结合,再在段与段连接处重叠点的基础上采用直线代替曲线,可有效降低程序运行时间,解决干扰问题。对实测数据进行仿真,结果表明,新算法比传统方法更有时效性,提高了水中检测的实时性。 展开更多
关键词 分段 固定拟合频率 直线代替曲线 连续谱提取
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舰船辐射噪声功率谱特征提取方法研究 被引量:14
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作者 杨向锋 张效民 孙继红 《鱼雷技术》 2006年第1期35-38,共4页
基于分段最小二乘曲线拟合方法,提出了一种的提取舰船噪声信号功率谱中线谱特征的新方法,通过一种新的坐标变换,用最小二乘曲线拟合方法精确提取了连续谱特征,将连续谱特征和线谱特征组合得到了舰船噪声的功率谱特征。利用BP神经网络对... 基于分段最小二乘曲线拟合方法,提出了一种的提取舰船噪声信号功率谱中线谱特征的新方法,通过一种新的坐标变换,用最小二乘曲线拟合方法精确提取了连续谱特征,将连续谱特征和线谱特征组合得到了舰船噪声的功率谱特征。利用BP神经网络对海上实录的两类目标噪声进行了分类识别,实验证明了方法的有效性,识别率达到90%以上,分类效果很好。 展开更多
关键词 局部拟合 线谱特征提取 连续谱特征提取 目标识别
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Distribution,fractionation,and contamination assessment of heavy metals in offshore surface sediments from western Xiamen Bay,China 被引量:2
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作者 Qiuli Yang Gongren Hu +2 位作者 Ruilian Yu Haixing He Chengqi Lin 《Acta Geochimica》 EI CAS CSCD 2016年第4期355-367,共13页
Surface sediment samples were collected at 21 offshore sites in western Xiamen Bay, Southeast China. Total concentrations of Li, V, Cr, Co, Ni, Cu, Zn, St, Mn, Pb, Ba, Fe, and Ti were determined by inductively coupled... Surface sediment samples were collected at 21 offshore sites in western Xiamen Bay, Southeast China. Total concentrations of Li, V, Cr, Co, Ni, Cu, Zn, St, Mn, Pb, Ba, Fe, and Ti were determined by inductively coupled plasma-optical emission spectrometry; Hg was determined by atomic fluorescence spectrometry. A modified BCR sequential extraction procedure was used to extract fractions of the above elements. Concentrations of Pb, Cr, and Hg at most sites met the primary standard criteria of Marine Sediment Quality except site S12 for Pb and S7 for Cr, while concentrations of Zn at 17 sites and Cu at seven sites exceeded the criteria. The mean concentration of Hg was three times higher than the background, with a possible source being the Jiulong River. Fe, Ti, Ba, Co, V, and Li dominated the residual phase, mainly from terrestrial input. Ni, Cr, Pb, and Hg in the non-residual phase varied largely between sites. Sr, Mn, Cu, and Zn were mainly in the non- residual fraction. Most sites showed considerable ecological risk; exceptions were site S7 (very high) and sites S10, S11, and S14 (moderate). Cu showed moderate-to-high pollution and Pb exhibited no-to-low pollution, while other metals had a non-pollution status according to their ratios of secondary phase to primary phase (RSP). Results of two assessment methods showed moderate pollution and a very high ecological risk for Cu, Zn, Ni, and Cr at site S7, which might be due to the local sewage treatment plant. 展开更多
关键词 Heavy metal Fractionation - Assessment Sediments DISTRIBUTION Western Xiamen Bay
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