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Ultrawide-band radar imagery from multiple incoherent frequency subband measurements 被引量:8
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作者 Xiaojian Xu Jia Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第3期398-404,共7页
The problem of combined radar imagery from multiple sparse frequency subbands initially incoherent to each other is of practical importance for radar target discrimination.A new coherent processing technique based on ... The problem of combined radar imagery from multiple sparse frequency subbands initially incoherent to each other is of practical importance for radar target discrimination.A new coherent processing technique based on probability density analysis of the subband data is proposed,which is applicable for radar imaging from measurements of two or more initially incoherent radar subbands.The coherence parameters for both amplitude and phase are obtained by combining modern spectral analysis with probability density estimation.The major advantage of the proposed technique lies in that it enables much more robust cohering for the sparse subband data of real-world complex targets. 展开更多
关键词 radar imagery coherent processing SUBBAND spectral analysis.
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Airport automatic detection in large space-borne SAR imagery 被引量:5
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作者 Shaoming Zhang Yi Lin Xiaohu Zhang Yingying Chen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第3期390-396,共7页
A method to detect airports in large space-borne synthetic aperture radar(SAR) imagery is studied.First,the large SAR imagery is segmented according to amplitude characteristics using maximum a posteriori(MAP) est... A method to detect airports in large space-borne synthetic aperture radar(SAR) imagery is studied.First,the large SAR imagery is segmented according to amplitude characteristics using maximum a posteriori(MAP) estimator based on the heavytailed Rayleigh model.The attention is then paid on the object of interest(OOI) extracted from the large images.The minimumarea enclosing rectangle(MER) of OOI is created via a rotating calipers algorithm.The projection histogram(PH) of MER for OOI is then computed and the scale and rotation invariant feature for OOI are extracted from the statistical characteristics of PH.A support vector machine(SVM) classifier is trained using those feature parameters and the airport is detected by the SVM classifier and Hough transform.The application in space-borne SAR images demonstrates the effectiveness of the proposed method. 展开更多
关键词 synthetic aperture radar(SAR) imagery airport detection image segmentation minimum-area enclosing rectangle support vector machine(SVM).
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Association Thinking and Imagery Thinking in Learning English Phrasal Verbs
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作者 朱贵生 《北京林业大学学报》 CAS CSCD 北大核心 1992年第S1期97-101,共5页
Phrasal verbs,such as look after,look forward to,look through,etc.,account for a large per-centage in English vocabulary,and they are even more difficult than single words for.English learn-ers to learn.For one reason... Phrasal verbs,such as look after,look forward to,look through,etc.,account for a large per-centage in English vocabulary,and they are even more difficult than single words for.English learn-ers to learn.For one reason,they are of a large quantity by formation.By looking throughWebster’s Third New International Dictionary(1961),we can see how colorful the forms of 展开更多
关键词 COLORFUL LOOKING centage vocabulary latter TELEVISION imagery instance THINKING DETAILS
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基于HHT和CSSD的多域融合自适应脑电特征提取方法 被引量:36
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作者 李明爱 崔燕 +1 位作者 杨金福 郝冬梅 《电子学报》 EI CAS CSCD 北大核心 2013年第12期2479-2486,共8页
为改善运动想象脑电信号特征提取的自适应性和实时性,提出一种基于希尔伯特-黄变换(HHT)与共空域子空间分解算法(CSSD)的特征提取方法(HCSSD).在对脑电信号进行预处理的基础上,定义一种相对距离准则优选脑电极组合;计算脑电的Hilbert瞬... 为改善运动想象脑电信号特征提取的自适应性和实时性,提出一种基于希尔伯特-黄变换(HHT)与共空域子空间分解算法(CSSD)的特征提取方法(HCSSD).在对脑电信号进行预处理的基础上,定义一种相对距离准则优选脑电极组合;计算脑电的Hilbert瞬时能量谱和边际能量谱,以获取脑电的时-频特征,并基于CSSD提取其空域特征,采用串行特征融合策略得到脑电的时-频-空特征;设计学习矢量量化神经网络分类器,实现脑电数据分类.在训练集与测试集间隔一周且减少导联数量的情况下,基于HCSSD对左手小指和舌头的运动想象ECoG脑电数据的平均识别率为92%.实验结果表明:HCSSD在增强特征提取方法的自适应性、改善实时性的同时,提高了脑电信号识别率,为便携式BCI系统在康复领域的应用创造了条件. 展开更多
关键词 脑机接口 运动想象 希尔伯特-黄变换 共空域子空间分解 特征融合 自适应 brain-computer interface (BCI) motor imagery (MI) hilbert-huang transform (HHT) common spatial sub-space decomposition (CSSD )
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中文版运动觉-视觉想象问卷在不同年龄、性别正常人群中的信度 被引量:6
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作者 刘华 程钰琦 +6 位作者 李洋 宋晴 史清钊 杨少峰 周军 阎守扶 荣湘江 《中国康复医学杂志》 CAS CSCD 北大核心 2017年第6期700-703,共4页
运动想象(motor imagery,MI)是指在无躯体参与运动时,有意识地在头脑中重现已经形成的动作表象或者形成新的动作表象[1]。在国外大部分相关的MI研究中,受试者均在入选时接受MI问卷的评估。Malouin等综合了各种版本MI问卷的优缺点,在2... 运动想象(motor imagery,MI)是指在无躯体参与运动时,有意识地在头脑中重现已经形成的动作表象或者形成新的动作表象[1]。在国外大部分相关的MI研究中,受试者均在入选时接受MI问卷的评估。Malouin等综合了各种版本MI问卷的优缺点,在2007年编制了运动觉-视觉想象问卷(the kinesthetic and visual imagery questionnaire,KVIQ-20)及它的简版KVIQ-10,检查者根据受试者进行MI时的主观感受,评估MI的清晰度(视觉想象,visual imagery,VI)和MI的感受强度(运动觉想象,kinesthetic imagery,KI)。 展开更多
关键词 重测信度 运动想象 动作表象 imagery 简版 内在一致性 α系数 QUESTIONNAIRE 分量表 多发性硬化
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从关联翻译理论分析中西文化语境下“月亮”意象 被引量:8
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作者 王琼 毛玲莉 《兰州大学学报(社会科学版)》 CSSCI 北大核心 2007年第2期137-142,共6页
以关联理论和关联翻译理论为理论框架,试图将文艺理论中的“意象”概念引入语用学和认知语言学的范畴,并进一步探究中西文化语境下,“月亮”意象在其源语认知语境和译语认知语境的关联性,以及影响“月亮”文学意象在传译中所呈现出的不... 以关联理论和关联翻译理论为理论框架,试图将文艺理论中的“意象”概念引入语用学和认知语言学的范畴,并进一步探究中西文化语境下,“月亮”意象在其源语认知语境和译语认知语境的关联性,以及影响“月亮”文学意象在传译中所呈现出的不同的民族文化心理、意象内涵、文化亏损和摇曳多姿的意象形态。 展开更多
关键词 月亮 意象翻译 关联翻译理论 文化语境 imagery
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《十九岁》,人生的片断(英文)
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作者 吴蓓 《思想战线》 CSSCI 北大核心 2009年第S1期98-100,共3页
"Nineteen",a poem by Elizabeth Alexander,is more than a story of a gir's "first summer away from home." Through the use of carefully chosen imagery and diction,the development of characters,the... "Nineteen",a poem by Elizabeth Alexander,is more than a story of a gir's "first summer away from home." Through the use of carefully chosen imagery and diction,the development of characters,the use of details,the variation in meters and the use of enjambment,the poet has parallels both the story of the speaker and that of her lover.More importantly,the lesson the speaker learns through her experience is especially rewarding. 展开更多
关键词 imagery and DICTION CHARACTERS DETAIL Enjambment
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谁是真正的美人?--比较斯宾塞十四行诗第15首与莎士比亚十四行诗第130首(英文)
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作者 姜凌 《思想战线》 CSSCI 北大核心 2009年第S1期48-49,共2页
Compared with Spenser's Sonnet 15 in which the speaker praises his beautiful lover by comparing her to various precious things such as Saphyres,Rubies,pearles,yvory,gold and silver,the speaker in Shakespeare's... Compared with Spenser's Sonnet 15 in which the speaker praises his beautiful lover by comparing her to various precious things such as Saphyres,Rubies,pearles,yvory,gold and silver,the speaker in Shakespeare's Sonnet 130 denies that his lover is as perfect as such wonderful things as the sun,coral,snow,roses,perfume,music and goddess,and thus portrays a more human and believable beauty.In addition,he describes his lovers in four senses-the visual sense,the sense of smell,the sense of sound,and the sense of motion.As a result,he creates a vivid and genuine beauty. 展开更多
关键词 imagery the Petrarchan CONVENTION BEAUTY
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浅析莎士比亚第73首十四行诗(英文)
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作者 佟晓牧 《思想战线》 CSSCI 北大核心 2009年第S1期96-97,共2页
Shakespeare's sonnet 73 impresses the readers with its rich images,metaphors,and profound diction.A study of the form that the poem has taken,of its imagery and its diction,we can conclude that the poem is not mer... Shakespeare's sonnet 73 impresses the readers with its rich images,metaphors,and profound diction.A study of the form that the poem has taken,of its imagery and its diction,we can conclude that the poem is not merely a cry of personal fear for and anxiety about aging and dying.Instead,it reflects the poet's sentimental attachment to life and resistance to death. 展开更多
关键词 FORM imagery DICTION
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影像的空间信息变化探测
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作者 张立杰 裴亮 马书英 《辽宁工程技术大学学报(自然科学版)》 CAS 北大核心 2006年第B06期75-77,共3页
为了解决影像空间信息变化探测中自动化程度和正确率均较低的问题,采用实验的方法探讨了基于属性、基于区域和基于像元的探测方法的原理,并结合专业软件ArcGIS对上述方法进行实验,取得了较好的实验结果。实验结果表明在自动发现的基础... 为了解决影像空间信息变化探测中自动化程度和正确率均较低的问题,采用实验的方法探讨了基于属性、基于区域和基于像元的探测方法的原理,并结合专业软件ArcGIS对上述方法进行实验,取得了较好的实验结果。实验结果表明在自动发现的基础上辅以GIS、影像处理技术以及交互的方式进行信息的探测可以取得较高的探测精度和较快的探测方法。 展开更多
关键词 变化探测 正射影像:Multi—temporal imagery
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A background refinement method based on local density for hyperspectral anomaly detection 被引量:5
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作者 ZHAO Chun-hui WANG Xin-peng +1 位作者 YAO Xi-feng TIAN Ming-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期84-94,共11页
For anomaly detection,anomalies existing in the background will affect the detection performance.Accordingly,a background refinement method based on the local density is proposed to remove the anomalies from thebackgr... For anomaly detection,anomalies existing in the background will affect the detection performance.Accordingly,a background refinement method based on the local density is proposed to remove the anomalies from thebackground.In this work,the local density is measured by its spectral neighbors through a certain radius which is obtained by calculating the mean median of the distance matrix.Further,a two-step segmentation strategy is designed.The first segmentation step divides the original background into two subsets,a large subset composed by background pixels and a small subset containing both background pixels and anomalies.The second segmentation step employing Otsu method with an aim to obtain a discrimination threshold is conducted on the small subset.Then the pixels whose local densities are lower than the threshold are removed.Finally,to validate the effectiveness of the proposed method,it combines Reed-Xiaoli detector and collaborative-representation-based detector to detect anomalies.Experiments are conducted on two real hyperspectral datasets.Results show that the proposed method achieves better detection performance. 展开更多
关键词 hyperspectral imagery anomaly detection background refinement the local density
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Information compression and speckle reduction for multifrequency polarimetric SAR images based on kernel PCA 被引量:4
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作者 Li Ying Lei Xiaogang Bai Bendu Zhang Yanning 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第3期493-498,共6页
Multifrequency polarimetric SAR imagery provides a very convenient approach for signal processing and acquisition of radar image. However, the amount of information is scattered in several images, and redundancies exi... Multifrequency polarimetric SAR imagery provides a very convenient approach for signal processing and acquisition of radar image. However, the amount of information is scattered in several images, and redundancies exist between different bands and polarizations. Similar to signal-polarimetric SAR image, multifrequency polarimetric SAR image is corrupted with speckle noise at the same time. A method of information compression and speckle reduction for multifrequency polarimetric SAR imagery is presented based on kernel principal component analysis (KPCA). KPCA is a nonlinear generalization of the linear principal component analysis using the kernel trick. The NASA/JPL polarimetric SAR imagery of P, L, and C bands quadpolarizations is used for illustration. The experimental results show that KPCA has better capability in information compression and speckle reduction as compared with linear PCA. 展开更多
关键词 kernel PCA multifrequency polarimetric SAR imagery information compression despeckling.
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Integration of spatial attractions between and within pixels for sub-pixel mapping 被引量:3
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作者 Qunming Wang Liguo Wang Danfeng Liu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第2期293-303,共11页
As a promising technique to enhance the spatial reso- lution of remote sensing imagery, sub-pixel mapping is processed based on the spatial dependence theory with the assumption that the land cover is spatially depend... As a promising technique to enhance the spatial reso- lution of remote sensing imagery, sub-pixel mapping is processed based on the spatial dependence theory with the assumption that the land cover is spatially dependent both within pixels and be- tween them. The spatial attraction is used as a tool to describe the dependence. First, the spatial attractions between pixels, sub- pixel/pixel spatial attraction model (SPSAM), are described by the modified SPSAM (MSPSAM) that estimates the attractions accord- ing to the distribution of sub-pixels within neighboring pixels. Then a mixed spatial attraction model (MSAM) for sub-pixel mapping is proposed that integrates the spatial attractions both within pix- els and between them. According to the expression of the MSAM maximumising the spatial attraction, the genetic algorithm is em- ployed to search the optimum solution and generate the sub-pixel mapping results. Experiments show that compared with SPSAM, MSPSAM and pixel swapping algorithm modified by initialization from SPSAM (MPS), MSAM can provide higher accuracy and more rational sub-pixel mapping results. 展开更多
关键词 remote sensing imagery sub-pixel mapping mixed spatial attraction model (MSAM) genetic algorithm (GA).
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Geometric active contour based approach for segmentation of high-resolution spaceborne SAR images 被引量:2
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作者 Shaoming Zhang Fang He +3 位作者 Yunling Zhang Jianmei Wang Xiao Mei Tiantian Feng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第1期69-76,共8页
Segmentation is the key step in auto-interpretation of high-resolution spaceborne synthetic aperture radar(SAR) images. A novel method is proposed based on integrating the geometric active contour(GAC) and the sup... Segmentation is the key step in auto-interpretation of high-resolution spaceborne synthetic aperture radar(SAR) images. A novel method is proposed based on integrating the geometric active contour(GAC) and the support vector machine(SVM)models. First, the images are segmented by using SVM and textural statistics. A likelihood measurement for every pixel is derived by using the initial segmentation. The Chan-Vese model then is modified by adding two items: the likelihood and the distance between the initial segmentation and the evolving contour. Experimental results using real SAR images demonstrate the good performance of the proposed method compared to several classic GAC models. 展开更多
关键词 image segmentation synthetic aperture radar(SAR) imagery support vector machine(SVM) geometric active contour(GAC)
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利用旋转平台模拟双河口羽流相互作用的研究 被引量:1
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作者 戴娟娟 袁野平 宋浩宸 《海洋与湖沼》 CAS CSCD 北大核心 2020年第5期1108-1117,共10页
本文通过旋转平台实验室实验的方法,探讨了双河口情况下两个羽流将如何发生相互作用。在研究中,提出了一种新颖的技术对河口羽流的各切面流场进行测量,来获得河口羽流多个平面的速度场及涡度场,并基于此模拟了双河口羽流系统的准三维结... 本文通过旋转平台实验室实验的方法,探讨了双河口情况下两个羽流将如何发生相互作用。在研究中,提出了一种新颖的技术对河口羽流的各切面流场进行测量,来获得河口羽流多个平面的速度场及涡度场,并基于此模拟了双河口羽流系统的准三维结构。通过对不同入流速度下的双河口羽流流场演变过程和内部结构进行了一系列对比研究,以期揭示上游河流的入流如何影响下游河口涡旋的形成及在羽流相互作用情形下各个羽流的演变。实验结果表明:随着上游入流流量的增加,上游羽流形成的沿岸流对下游河口涡旋沿岸迁移的促进和离岸输运的抑制作用将更加显著。特别是在上游入流流量等于或大于下游入流流量的情况下,下游羽流河口涡旋的体积增长明显较单一河口情况放缓。在上游入流流量较大的情况下,下游原有河口涡旋被推向更下游位置,在远离河口的位置形成另一个河口涡旋。在垂直方向上,我们可以观察到高上游入流流量条件下的下游河口涡旋的深度较小,更有利于形成三层流体的情况。本研究对多河口近海流域的营养盐及污染物的输运情况等社会和生态问题的研究有着重要的意义。 展开更多
关键词 双河口 旋转平台 分层PIV(Partical imagery Velocimetry)技术 河口羽流 河口涡旋
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三首宋词中意向的简要分析(英文)
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作者 谢萍 《思想战线》 CSSCI 北大核心 2011年第S1期496-497,共2页
In the history of Chinese literature,Tz's of Song Dynasty abounds in lyrics infused with sentimental gracefulness,whose most distinctive feature is the employment of rich and varied imagery.This paper is to analyz... In the history of Chinese literature,Tz's of Song Dynasty abounds in lyrics infused with sentimental gracefulness,whose most distinctive feature is the employment of rich and varied imagery.This paper is to analyze the imagery of three Tz'u lyrics of profound lamentation so as to show how the extraordinary manipulation of imagery makes the three lyrics the master pieces of their kind. 展开更多
关键词 Tz’u LYRICS amentation imagery
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Escape as a Mode of Existence:On Ruan Ji' s Escapism Complex
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作者 Qu Jingyi 《学术界》 CSSCI 北大核心 2018年第3期244-259,共16页
Scholarly research regarding Ruan Ji 阮籍 has predom inantly revolved either around his five-word Yonghuai Poetry( Poems from my Heart,詠懷詩). From the perspective of Escape and Escapism,the paper we call the imagery... Scholarly research regarding Ruan Ji 阮籍 has predom inantly revolved either around his five-word Yonghuai Poetry( Poems from my Heart,詠懷詩). From the perspective of Escape and Escapism,the paper we call the imagery in Ruan Ji's poetry,including his Fu-Poetry,four-word Poems as well as five-word poems,is escapist imagery. Ruan Ji has a kind of escapism complex which the paper talks over by case studies,i. e."Dongping fu"东平赋,four-word Poem IX and Poem XIII,and five-word Poem I and Poem LX X IX to find a new perspective to read Ruan Ji. This escapism complex is closely connected to Ruan Ji's unique mode of existence. 展开更多
关键词 ESCAPE and escapism Ruan JI 阮籍 escapist imagery COMPLEX
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