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Bi-Spectrum Scattering Model for Dielectric Randomly Rough Surface 被引量:3
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作者 刘宁 李宗谦 《Tsinghua Science and Technology》 SCIE EI CAS 2003年第5期617-623,共7页
The bistatic scattering model is offen used for remote microwave sensing. The bi-spectrum model (BSM) for conducting surfaces was used to develop a scattering model for dielectric randomly rough surfaces to estimate ... The bistatic scattering model is offen used for remote microwave sensing. The bi-spectrum model (BSM) for conducting surfaces was used to develop a scattering model for dielectric randomly rough surfaces to estimate their bistatic scattering coefficients. The model for dielectric rough surfaces differs from the BSM for a conducting surface by including Fresnell reflection and transmission from dielectric rough surfaces. The bistatic scattering coefficients were defined to satisfy the reciprocal theorem. Values calculated using the BSM for dielectric randomly rough surfaces compare well with those of the integral equation model (IEM) and with experimental data, showing that the BSM accuracy is acceptable and its range of validity is similar to that of IEM while the BSM expression is simpler than that of IEM. 展开更多
关键词 dielectric randomly rough surface spectral domain bi-spectrum method bistatic scattering coefficients bi-spectrum scattering model microwave remote sensing
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调速阀故障诊断的AR双谱定阶方法比较 被引量:7
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作者 蒋雨燕 黄宜坚 《华侨大学学报(自然科学版)》 CAS 北大核心 2009年第2期123-126,共4页
为解决故障诊断中确定最优的自回归(AR)模型阶数的问题,运用最终预测误差(FPE)、阿凯克信息准则(AIC)、贝叶斯信息准则(BIC),以及奇异值分解(SVD)的切片法和Frobenius法共5种定阶方法对调速阀的故障进行自回归模型定阶实验.结果表明,FPE... 为解决故障诊断中确定最优的自回归(AR)模型阶数的问题,运用最终预测误差(FPE)、阿凯克信息准则(AIC)、贝叶斯信息准则(BIC),以及奇异值分解(SVD)的切片法和Frobenius法共5种定阶方法对调速阀的故障进行自回归模型定阶实验.结果表明,FPE,AIC,BIC及SVD切片法确定的阶数较低,而用SVD Frobenius法确定的阶数较高.通过不同阶数、不同故障的调速阀故障诊断实验可知,用SVD Frobenius法建立的AR模型效果优于其他方法. 展开更多
关键词 调速阀 故障诊断 自回归模型 时间序列双谱 定阶方法 奇异值分解
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