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非线性映射法用于鼠尾草属植物的分析鉴定 被引量:6
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作者 汪红 王强 《中国野生植物资源》 2006年第4期51-54,共4页
运用梯度洗脱测定鼠尾草鼠植物中9个主要成分含量的实验数据,对鼠尾草属13个种26个样本进行非线性映射分析鉴定。结合BASICA语言程序,采用主成分分析法给出二维平面上的初始坐标,并运用逐点迭代循环至误差函数E最小,得到各样本的最终坐... 运用梯度洗脱测定鼠尾草鼠植物中9个主要成分含量的实验数据,对鼠尾草属13个种26个样本进行非线性映射分析鉴定。结合BASICA语言程序,采用主成分分析法给出二维平面上的初始坐标,并运用逐点迭代循环至误差函数E最小,得到各样本的最终坐标,映射到二维空间,进行直观分析。能够直观地将弧隔鼠尾草亚属与荔枝草亚属的样本分离开来,具有一定合理性与实用性。 展开更多
关键词 线性映射法 鼠尾草属 主成分分析
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去除Lamb波频散的线性映射法 被引量:3
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作者 骆英 徐彩军 +3 位作者 徐晨光 徐桂东 杨国英 王自平 《实验力学》 CSCD 北大核心 2018年第5期734-742,共9页
Larab波常被用于板壳结构的无损检测,然而Lamb波的频散效应会导致板中损伤反射信号的渡越时间信息无法准确提取,因而影响损伤定位及成像的精度。本文引入线性映射方法,用线性频率一波数关系取代原有非线性的频散关系,从而去除激励... Larab波常被用于板壳结构的无损检测,然而Lamb波的频散效应会导致板中损伤反射信号的渡越时间信息无法准确提取,因而影响损伤定位及成像的精度。本文引入线性映射方法,用线性频率一波数关系取代原有非线性的频散关系,从而去除激励中心频率附近的频散效应。分别采用数值模拟和实验的方法分析了频散去除的效果,进而结合相控阵成像算法对金属板中的损伤进行成像研究。结果表明,利用线性映射法去除频散可以显著提高含损伤散射信号的信噪比,提升相控阵损伤成像方法对损伤定位的准确性。 展开更多
关键词 LAMB波 频散 线性映射法 相控阵成像算 损伤定位
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非线性主轴降维映射法在固体火箭发动机设计优化中的应用 被引量:2
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作者 欧海英 张为华 +1 位作者 赵经成 付战平 《推进技术》 EI CAS CSCD 北大核心 2007年第4期346-351,共6页
为在二维或三维空间中表达固体火箭发动机高维设计空间,引入非线性主轴降维映射法对多维非线性设计优化问题进行降维处理。以某大型固体火箭发动机设计问题为例,将10变量4有效约束优化问题降维映射到二维空间进行研究,拟合的非线性主轴... 为在二维或三维空间中表达固体火箭发动机高维设计空间,引入非线性主轴降维映射法对多维非线性设计优化问题进行降维处理。以某大型固体火箭发动机设计问题为例,将10变量4有效约束优化问题降维映射到二维空间进行研究,拟合的非线性主轴降维映射模型中,目标函数和约束函数的相对误差控制在1.5%以内。研究表明,非线性主轴降维映射法具有发现多变量非线性优化数学模型本征特性的特点,能对设计变量重要性排序;通过降维展示设计空间全景,为优化算法和优化初始点优选提供了直观、有力的工具;优化轨迹实时展示为优化算法性质研究及算法切换提供了依据;根据优化轨迹从优化结果在降维空间中的位置能够判断优化结果是否具有全局最优解特性。 展开更多
关键词 固体火箭发动机 优化设计 线性主轴降维映射^+ 设计空间全景展示^+ 优化轨迹显示^+
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过程系统寻优非线性映射主轴分析法
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作者 鄢烈祥 麻德贤 《湖北工业大学学报》 1998年第4期13-18,共6页
应用人工神经网络和拓扑映射技术,提出非线性映射主轴分析法 该法将一个多维空间的非线性问题降维映射到二维空间,籍目标函数等值分布曲线的分析,决策出最优点或最优区域。
关键词 神经网络 线性映射主轴分析 最优化
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Locally linear embedding-based seismic attribute extraction and applications 被引量:5
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作者 刘杏芳 郑晓东 +2 位作者 徐光成 王玲 杨昊 《Applied Geophysics》 SCIE CSCD 2010年第4期365-375,400,401,共13页
How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key,which is usually solved by reducing dimensionality.Principle co... How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key,which is usually solved by reducing dimensionality.Principle component analysis(PCA) is the most widely-used linear dimensionality reduction method at present.However,the relationships between seismic attributes and reservoir features are non-linear,so seismic attribute dimensionality reduction based on linear transforms can't solve non-linear problems well,reducing reservoir prediction precision.As a new non-linear learning method,manifold learning supplies a new method for seismic attribute analysis.It can discover the intrinsic features and rules hidden in the data by computing low-dimensional,neighborhood-preserving embeddings of high-dimensional inputs.In this paper,we try to extract seismic attributes using locally linear embedding(LLE),realizing inter-horizon attributes dimensionality reduction of 3D seismic data first and discuss the optimization of its key parameters.Combining model analysis and case studies,we compare the dimensionality reduction and clustering effects of LLE and PCA,both of which indicate that LLE can retain the intrinsic structure of the inputs.The composite attributes and clustering results based on LLE better characterize the distribution of sedimentary facies,reservoir,and even reservoir fluids. 展开更多
关键词 attribute optimization dimensionality reduction locally linear embedding(LLE) manifold learning principle component analysis(PCA)
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Approximate Analytic Solution of Solitary Wave for a Class of Nonlinear Disturbed Long-Wave System 被引量:5
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作者 莫嘉琪 姚静荪 唐荣荣 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第7期27-30,共4页
In this paper, the approximate expressions of the solitary wave solutions for a class of nonlinear disturbed long-wave system are constructed using the homotopie mapping method.
关键词 nonlinear long-wave equation solitary wave approximate analytic solution
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A SPARSE PROJECTION CLUSTERING ALGORITHM 被引量:4
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作者 Xie Zongbo Feng Jiuchao 《Journal of Electronics(China)》 2009年第4期549-551,共3页
A clustering algorithm based on Sparse Projection (SP), called Sparse Projection Clus- tering (SPC), is proposed in this letter. The basic idea is applying SP to project the observed data onto a high-dimensional spars... A clustering algorithm based on Sparse Projection (SP), called Sparse Projection Clus- tering (SPC), is proposed in this letter. The basic idea is applying SP to project the observed data onto a high-dimensional sparse space, which is a nonlinear mapping with an explicit form and the K-means clustering algorithm can be therefore used to explore the inherent data patterns in the new space. The proposed algorithm is applied to cluster a complete artificial dataset and an incomplete real dataset. In comparison with the kernel K-means clustering algorithm, the proposed algorithm is more efficient. 展开更多
关键词 Sparse Projection Clustering (SPC) K-means clustering Kernel K-means clustering
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Chinese Fuzzy Ontology Mapping Based on Support Vector Machine 被引量:2
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作者 Liu Jie Ma Yun +1 位作者 Tang Shiping Lu Peng 《China Communications》 SCIE CSCD 2012年第3期134-144,共11页
Taking into account that fuzzy ontology mapping has wide application and cannot be dealt with in many fields at present,a Chinese fuzzy ontology model and a method for Chinese fuzzy ontology mapping are proposed.The m... Taking into account that fuzzy ontology mapping has wide application and cannot be dealt with in many fields at present,a Chinese fuzzy ontology model and a method for Chinese fuzzy ontology mapping are proposed.The mapping discovery between two ontologies is achieved by computing the similarity between the concepts of two ontologies.Every concept consists of four features of concept name,property,instance and structure.First,the algorithms of calculating four individual similarities corresponding to the four features are given.Secondly,the similarity vectors consisting of four weighted individual similarities are built,and the weights are the linear function of harmony and reliability.The similarity vector is used to represent the similarity relation between two concepts which belong to different fuzzy ontolgoies.Lastly,Support Vector Machine(SVM) is used to get the mapping concept pairs by the similarity vectors.Experiment results are satisfactory. 展开更多
关键词 fuzzy ontology mapping similarity ag-gregation fuzzy knowledge representation SVM
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Power Big Data Fusion Prediction
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作者 Liu Yan Song Yu +1 位作者 Li Gang Liang Weiqiang 《Computer Technology and Application》 2016年第3期165-171,共7页
This paper is a research on the characteristics of power big data. According to the characteristics of "large volume", "species diversity", "sparse value density", "fast speed" of the power big data, a predict... This paper is a research on the characteristics of power big data. According to the characteristics of "large volume", "species diversity", "sparse value density", "fast speed" of the power big data, a prediction model of multi-source information fusion for large data is established, the fusion prediction of various parameters of the same object is realized. A combined algorithm of Map Reduce and neural network is used in this paper. Using clustering and nonlinear mapping ability of neural network, it can effectively solve the problem of nonlinear objective function approximation, and neural network is applied to the prediction of fusion. In this paper, neural network model using multi layer feed forward network--BP neural network. Simultaneously, to achieve large-scale data sets in parallel computing, the parallelism and real-time property of the algorithm should be considered, further combined with Reduce Map model, to realize the parallel processing of the algorithm, making it more suitable for the study of the fusion of large data. And finally, through simulation, it verifies the feasibility of the proposed model and algorithm. 展开更多
关键词 Power big data fusion prediction Map Reduce BP neural network.
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PWM控制的DC--DC变换器中的混沌现象的研究
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作者 王媛彬 《电源世界》 2011年第2期21-23,共3页
本文以闭环PWM控制的Buck开关变换器为例,采用非线性迭代映射法对其电感电流连续模式工作下,变换器中出现的混沌现象进行了分析研究,并采用PSPICE进行了计算机仿真验证,从而通过理论和仿真证明了在某些电路参数下系统里会出现多脉冲、... 本文以闭环PWM控制的Buck开关变换器为例,采用非线性迭代映射法对其电感电流连续模式工作下,变换器中出现的混沌现象进行了分析研究,并采用PSPICE进行了计算机仿真验证,从而通过理论和仿真证明了在某些电路参数下系统里会出现多脉冲、倍周期等混沌现象。 展开更多
关键词 开关变换器 PWM 线性迭代映射 混沌
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PWM Buck变换器中的混沌现象的研究
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作者 王嫒彬 《电源世界》 2008年第5期25-27,共3页
本文以闭环PWM控制的Buck开关变换器为例,采用非线性迭代映射法对电感电流连续模式下变换器中出现的混沌现象进行了分析研究,确定了开关转换时刻及转换时刻的输出电压和电感电流的值,最后采用PSpice进行了计算机仿真验证。
关键词 开关变换器 PWM 线性迭代映射 混沌
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Time-varying stiffness analysis of double-row tapered roller bearing based on the mapping structure of bearing stiffness matrix
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作者 Di Yang Xi Wang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第11期89-100,共12页
Time-varying stiffness is one of the most important dynamic characteristics of rolling element bearings.The method of analyzing the elements in the bearing stiffness matrix is usually adopted to investigate the charac... Time-varying stiffness is one of the most important dynamic characteristics of rolling element bearings.The method of analyzing the elements in the bearing stiffness matrix is usually adopted to investigate the characteristics of bearing stiffness.Linear mapping structure of the bearing stiffness matrix is helpful to understand the varying compliance excitation and its influence on vibration transmission.In this study,a method to analyze the mapping structure of bearing stiffness matrix is proposed based on the singular value decomposition of block matrices in the stiffness matrix.Not only does this method have the advantages of coordinate transformation independence and unit independence,but also the analysis procedure involved is geometrically intuitive.The time-varying stiffness matrix of double-row tapered bearing is calculated and analyzed using the proposed method under two representative load cases.The principal stiffnesses and principal axes defined in the method together indicate the dominant and insignificant stiffness properties with the corresponding directions,and the vibration transmission properties are also revealed.Besides,the coupling behaviors between different shaft motions are found during the analysis of mapping structure.The mechanism of the generation of varying compliance excitation is also revealed. 展开更多
关键词 Rolling element bearing Time-varying stiffness matrix Mapping structure Vibration transmission Varying compliance excitation
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