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一种用于超声信号降噪的非凸变量重叠群稀疏变分方法 被引量:2
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作者 张家玮 焦敬品 +1 位作者 陈昌华 高翔 《仪器仪表学报》 EI CAS CSCD 北大核心 2022年第4期234-245,共12页
粗大晶粒产生的大量散射噪声而导致的超声检测信号信噪比低问题是粗晶结构超声检测面临的一大难题。针对现有稀疏降噪方法在波形失真和幅值衰减方面的不足,本文提出了一种基于非凸变量重叠群稀疏变分的超声信号降噪方法。基于含散射噪... 粗大晶粒产生的大量散射噪声而导致的超声检测信号信噪比低问题是粗晶结构超声检测面临的一大难题。针对现有稀疏降噪方法在波形失真和幅值衰减方面的不足,本文提出了一种基于非凸变量重叠群稀疏变分的超声信号降噪方法。基于含散射噪声的典型超声信号,分析了非凸变量重叠群稀疏变分方法的主要参数(如非凸变量函数类型、正则化参数和乘法因子等)对其降噪效果的影响,并确定了适合超声信号降噪处理的参数选择依据。在此基础上,将非凸变量重叠群稀疏变分方法应用于典型钢锭超声检测信号的降噪处理。结果表明,该方法能够很好剔除钢锭超声检测信号中的散射噪声,提高了钢锭超声全聚焦成像的信噪比6 dB以上,研究工作为粗晶材料超声检测作了有益探索。 展开更多
关键词 超声检测 非凸变量函数 重叠群稀疏变分 散射噪声
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General Pattern and Neighborhood Search Algorithms for Non-Convex Unit Commitment
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作者 Li Jinghua Lan Fei 《Electricity》 2014年第2期21-28,35,共9页
This paper presents a new approach to solve mixed-variable unit commitment(UC) problems with non-smooth cost functions based on a generalized pattern search filter(GPS-filter) algorithm. A GPS-filter algorithm does no... This paper presents a new approach to solve mixed-variable unit commitment(UC) problems with non-smooth cost functions based on a generalized pattern search filter(GPS-filter) algorithm. A GPS-filter algorithm does not require any information about the gradient of the objective function while searching for an optimum solution. At the same time, it is available for solving mixed-variable optimization problems, which is very suitable for UC. A new suitable discrete neighborhood structure with UC characteristics is proposed to improve GPS-filter efficiently. A lot of multiple units' states are fixed before search; hence, the polling search of discrete variable is efficient for a few uncertain units. Numerical experiments are included to demonstrate the proposed approach's ability to handle the highly nonlinear, discontinuous, non-smooth cost functions and mixed variables of the UC problem. 展开更多
关键词 optimal power system operation pattern search method filter method unit commitment neighborhood search
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