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正反相切抛物线方法拟合通风机特性曲线 被引量:6
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作者 尹昌胜 刘剑 邓立军 《辽宁工程技术大学学报(自然科学版)》 CAS 北大核心 2015年第1期77-81,共5页
针对实际应用中通风机特性曲线拟合中存在2次多项式拟合存在假收敛、5次多项式拟合同时存在曲线振荡和假收敛,拟合的曲线与实际通风机特性曲线的"驼峰"形状相差较大等问题,提出一种基于正反平滑相切抛物线的风机特性曲线近似... 针对实际应用中通风机特性曲线拟合中存在2次多项式拟合存在假收敛、5次多项式拟合同时存在曲线振荡和假收敛,拟合的曲线与实际通风机特性曲线的"驼峰"形状相差较大等问题,提出一种基于正反平滑相切抛物线的风机特性曲线近似拟合方法,开口向下的正抛物线拟合通风机的稳定工作区域,开口向上的反抛物线拟合通风机的不稳定区域,正反两条抛物线在交点处平滑相切,使得拟合曲线近似"驼峰"形状,避免了2次多项式假收敛和5次多项式曲线振荡问题. 展开更多
关键词 风机特性曲线 正反抛物线 极大工况点 假收敛 曲线振荡
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一种基于差分进化理论优化的隐式空间映射算法及其应用
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作者 张友俊 顾魁 《计算机应用与软件》 CSCD 2016年第8期246-248,共3页
标准隐式空间映射算法在优化滤波器的过程中可能会出现假收敛现象,从而导致模型之间建立的映射关系偏弱,使得整体的优化效率降低。介绍一种改进算法,通过引入差分进化算法(DE)搜索目标函数的全局最优解,避免优化过程出现假收敛。最后应... 标准隐式空间映射算法在优化滤波器的过程中可能会出现假收敛现象,从而导致模型之间建立的映射关系偏弱,使得整体的优化效率降低。介绍一种改进算法,通过引入差分进化算法(DE)搜索目标函数的全局最优解,避免优化过程出现假收敛。最后应用该算法优化一种多层结构的LTCC微带滤波器。实验结果表明,旨在获取更好映射关系的新算法在同样满足设计指标的条件下,所用迭代次数少,用时也更短,具备良好的可行性和高效性。 展开更多
关键词 差分进化算法 映射关系 假收敛 LTCC滤波器
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Linear inversion-imaging method based on joint primary refl ected waves and surface-related multiples
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作者 Ouyang Min Sheng Shen +1 位作者 Liu Shou-Wei Feng Bo 《Applied Geophysics》 SCIE CSCD 2022年第3期366-377,471,共13页
In marine seismic exploration,especially in deep-water and hard ocean-bottom cases,free-surface multiples are strongly developed.Compared with primary waves,the wider illumination aperture of the multiples is benefici... In marine seismic exploration,especially in deep-water and hard ocean-bottom cases,free-surface multiples are strongly developed.Compared with primary waves,the wider illumination aperture of the multiples is beneficial for high-resolution seismic imaging.In this study,by introducing a new compound source composed of primaries and free-surface multiples and by ignoring internal multiples,we derive a new linearized forward problem(free-surface-multiple prediction model)under a weak-scattering assumption(i.e.,first-order Born approximation).On the basis of the new linearized problem,we propose a joint inversion-imaging method by simultaneously using the primaries and free-surface multiples under the general framework of least square inversion.To eliminate the crosstalk artifacts introduced by the cross-correlation of multiples with different orders,we prove that the crosstalk artifacts can be gradually eliminated during the inversion if a proper step length is selected.Synthetic-andfield-data tests demonstrate the effectiveness of the proposed method. 展开更多
关键词 Free-surface multiple joint linearized imaging crosstalk artifact iterative convergence
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INFERENCE ON COEFFICIENT FUNCTION FOR VARYING-COEFFICIENT PARTIALLY LINEAR MODEL
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作者 Jingyan FENG Riquan ZHANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第6期1143-1157,共15页
One important model in handling the multivariate data is the varying-coefficient partially linear regression model. In this paper, the generalized likelihood ratio test is developed to test whether its coefficient fun... One important model in handling the multivariate data is the varying-coefficient partially linear regression model. In this paper, the generalized likelihood ratio test is developed to test whether its coefficient functions are varying or not. It is showed that the normalized proposed test follows asymptotically x2-distribution and the Wilks phenomenon under the null hypothesis, and its asymptotic power achieves the optimal rate of the convergence for the nonparametric hypotheses testing. Some simulation studies illustrate that the test works well. 展开更多
关键词 x2-distribution generalized likelihood ratio optimal rate of convergence varying-coefficientpartially linear model Wilks phenomenon.
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