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Novel linear search for support vector machine parameter selection

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第11期12卷 885-896页

作者： Hong-xia PANG Wen-de DONG Zhi-hai xu Hua-jun feng qi LI Yue-ting CHEN State Key Laboratory of Optical Instrumentation Zhejiang University Hangzhou 310027 China

Selecting the optimal parameters for support vector machine (SVM) has long been a hot research topic. Aiming for support vector classification/regression (SVC/SVR) with the radial basis function (RBF) kernel, we summarize the rough line rule of the penalty parameter and kernel width, and propose a novel linear search method to obtain these two optimal parameters. We use a direct-setting method with thresholds to set the epsilon parameter of SVR. The proposed method directly locates the right search field, which greatly saves computing time and achieves a stable, high accuracy. The method is more competitive for both SVC and SVR. It is easy to use and feasible for a new data set without any adjustments, since it requires no parameters to set.

关键词： Support vector machine (SVM) Rough line rule Parameter selection Linear search Motion prediction

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一种振膜式电流传感器

电力系统自动化 2009年第8期33卷 81-83页

作者：徐启峰福州大学电气工程与自动化学院福建省福州市350108

介绍了一种全新思路的电流传感器——振膜式电流传感器(FVCT)。FVCT的工作原理是基于永磁体的磁场力对电流的作用。实现方法是用一片置入电流线圈的薄膜,电流线圈分流了主导线电流,永磁体磁场力对电流的作用使薄膜振动(交流)或进动(直... 详细信息

介绍了一种全新思路的电流传感器——振膜式电流传感器(FVCT)。FVCT的工作原理是基于永磁体的磁场力对电流的作用。实现方法是用一片置入电流线圈的薄膜,电流线圈分流了主导线电流,永磁体磁场力对电流的作用使薄膜振动(交流)或进动(直流),其幅值是电流的线性函数。从低电位经光纤向高电位发射普通光束,经薄膜反射后再传回低电位,反射光的强度随薄膜的振动或进动发生变化,通过测量光强的变化得到需要测量的电流。同时,传输光纤实现了高电位与低电位之间的电气隔离。FVCT高电位无源,既可以用于交流电流的测量,也可以用于直流电流的测量,不受电压等级的限制,能真实地反映谐波和故障暂态非周期分量。原理样机初步实现了0.5级测量准确度。

关键词：电流传感器电流互感器振膜式

Developmental expression of three prmt genes in Xenopus

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Zoological Research 2019年第2期40卷 102-107页

作者： Cheng-Dong Wang Xiao-Fang Guo Thomas Chi Bun Wong Hui Wang xu-feng qi Dong-qing Cai Yi Deng Hui Zhao Key Laboratory for Regenerative Medicine Ministry of EducationSchool of Biomedical Sciences Faculty of Medicine The Chinese University of Hong Kong Key Laboratory for Regenerative Medicine of Ministry of Medicine of Ministry of Education Jinan University Department of Developmental & Regenerative Biology College of Life Science and Technology Jinan University Guangdong Provincial Key Laboratory of Cell Microenvironment Department of Biology South University of Science and Technology of China Kunming Institute of Zoology Chinese Academy of Sciences-The Chinese University of Hong Kong Joint Laboratory of Bioresources and Molecular Research of Common Diseases

DEAR EDITOR Protein arginine methyltransferases (PRMTs)are involved in many cellular processes via the arginine methylation of histone or non-histone *** examined the expression patterns of prmt4,prmt7,and prmt9 during embryogenesis in Xenopus using whole-mount in situ hybridization and quantitative reverse transcription polymerase chain reaction (RT-PCR).Xenopus prmt4 and prmt7 were expressed in the neural crest,brain,and spinal cord,and also detected in the eye,branchial arches,and heart at the tailbud *** print9 signals were not detected in Xenopus embryos until the late tailbud stage when weak expression was observed in the branchial *** RT-PCR indicated that the expression of prmt4 and prmt7 was up-regulated during the neurula stage,whereas prmt9 maintained its low expression until the late tailbud stage,consistent with the whole-mount in situ hybridization ***,the developmental expression patterns of these three print genes in Xenopus embryos provide a basis for further functional study of such genes.

关键词： Developmental expression prmt genes Xenopus

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非晶合金J-A模型修正

电机与控制学报 2014年第7期18卷 86-93页

作者：李超徐启峰福州大学电气工程与自动化学院福建福州350108

非晶合金已广泛应用在电力设备中,但缺乏对其磁滞回线温度特性和带气隙磁环建模方法的研究。本文在J-A模型的基础上,通过修正模型参数的方法引入温度系数,实现了不同温度下非晶合金磁滞回线建模;分析了磁致伸缩效应和热膨胀效应对带气... 详细信息

非晶合金已广泛应用在电力设备中,但缺乏对其磁滞回线温度特性和带气隙磁环建模方法的研究。本文在J-A模型的基础上,通过修正模型参数的方法引入温度系数,实现了不同温度下非晶合金磁滞回线建模;分析了磁致伸缩效应和热膨胀效应对带气隙磁环的影响,提出了磁致伸缩系数和热膨胀系数随温度变化近似公式,并修正了带气隙磁环的气隙长度值;最终建立了非晶合金附加温度参数和气隙参数的磁滞模型。利用非晶合金磁致伸缩特性和磁滞回线温度特性的共同作用,提出了一种具有稳定温度特性的气隙磁心设计方法,以铁镍基非晶合金为例进行了仿真和实验验证,二者结果吻合,证明了模型和设计方法的有效性。

关键词：磁滞回线建模非晶合金 Jiles-Atherton理论温度特性气隙

基于SURF和矩阵乘法的超大规模遥感图像亚像素配准算法研究

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红外技术 2017年第1期39卷 44-52页

作者：徐全飞冯旗中国科学院上海技术物理研究所上海200083

图像配准是一项基本而又非常关键的图像预处理技术。在很多应用领域,要求配准精度达到亚像素级。现有的相位相关法具有精度高、计算简单等特点,但是随着图像规模的增大,计算付出的时间代价是巨大的。本文提出基于SURF和矩阵乘法相位相... 详细信息

图像配准是一项基本而又非常关键的图像预处理技术。在很多应用领域,要求配准精度达到亚像素级。现有的相位相关法具有精度高、计算简单等特点,但是随着图像规模的增大,计算付出的时间代价是巨大的。本文提出基于SURF和矩阵乘法相位相关法的超大规模遥感图像亚像素配准算法,采用化整为零的方法,首先把整幅图像划分成不同区域,其次使用改进的Canny算法进行边缘分割,去除无用信息,再次使用SURF算法提取特征,最后在关键点周围使用矩阵乘法相位相关估计图像亚像素偏移量。实验表明本文提出的算法不仅提高了算法运行速度,同时也解决了图像尺寸太大导致一般计算机无法处理的问题。并且由于矩阵乘法相位相关的良好抗噪声特性,因此即使存在噪声,算法仍然可以获得较高的亚像素偏移量估计精度。

关键词：图像配准 SURF算法矩阵乘法相位相关亚像素

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一种基于伪标签的半监督少样本学习模型

电子学报 2019年第11期47卷 2284-2291页

作者：余游冯林王格格徐其凤四川师范大学计算机科学学院

如何将带有大量标记数据的源域知识模型迁移至带有少量标记数据的目标域是少样本学习研究领域的热点问题.针对现有的少样本学习算法在源域数据与目标域数据的特征分布差异较大时存在的泛化能力较弱的问题,提出一种基于伪标签的半监督少... 详细信息

如何将带有大量标记数据的源域知识模型迁移至带有少量标记数据的目标域是少样本学习研究领域的热点问题.针对现有的少样本学习算法在源域数据与目标域数据的特征分布差异较大时存在的泛化能力较弱的问题,提出一种基于伪标签的半监督少样本学习模型FSLSS(Few-Shot Learning based on Semi-Supervised).首先,利用pytorch深度学习框架建立一个关系型深度学习网络,并使用源域数据对网络进行预训练;然后,使用此网络对目标域数据进行分类预测,将分类概率最大的类标签作为数据的伪标签;最后,利用目标域的伪标签数据和源域的真实标签数据对网络进行混合训练,并重复伪标签标记与混合训练过程.实验结果表明,相对于现有主流少样本学习算法,FSLSS模型有更好的泛化能力及知识迁移效果.

关键词：少样本学习半监督学习伪标签迁移学习

Yeast two-hybrid screening for proteins that interact with α1-adrenergic receptors

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Acta Pharmacologica Sinica 2004年第11期 87-94页

作者： Tan ZHANG, qi xu, feng-rong CHEN, qi-de HAN, You-yi ZHANGInstitute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Science,Ministry of Education, Beijing 100083, ChinaNow in Department of Cardiology, Peking University Third Hospital, Beijing, China.

AIM: To find novel proteins that may bind to α1A-adrenergic receptor (α1A-AR) and investigate their interactions with the other two α1-AR subtypes (α1B-AR and α1D-AR) with an expectation to provide new leads for the function study of the receptors. METHODS: Yeast two-hybrid assay was performed to screen a human brain cDNA library using the C terminus of α1A-AR (α1A-AR-CT) as bait. X-Gal assay and o-nitrophenyl-beta-D-galactopyranoside (ONPG) assay were subsequently conducted to further qualitatively or quantitatively confirm the interactions between receptors and the three identified proteins. RESULTS: (1) Selection medium screening identified segments of bone morphogenetic protein-1 (BMP-1), active Bcr-related protein (Abr), and filamin-C as binding partners of α1A-AR-CT in yeast cells respectively. Besides, protein segments of BMP-1 and Abr could only specifically interact with α1A-AR-CT while filamin-C segment interacted with all three α1-AR subtypes. (2) In X-Gal assay, the co-transformants

关键词： active Bcr-related protein α1-adrenergic receptors bone morphogenetic protein-1 filamin-C yeasts two-hybrid system techniques beta-galactosidase

竹叶提取物通过调控Akt/HIF-1α通路抑制低氧条件下人乳腺癌MCF-7细胞的恶性生长

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西安交通大学学报（医学版） 2018年第1期39卷 121-126页

作者：徐其锋温晓琼河南省中医院乳腺科河南郑州450002

目的探究竹叶提取物对低氧条件下人乳腺癌MCF-7细胞恶性生长的影响及分子机制。方法将培养的人乳腺癌MCF-7细胞随机分为正常组、低氧组以及0.2、0.4、0.8μg/mL竹叶提取物组和0.8μg/mL竹叶提取物组+IGF-1组。CCK-8法检测各组细胞的增... 详细信息

目的探究竹叶提取物对低氧条件下人乳腺癌MCF-7细胞恶性生长的影响及分子机制。方法将培养的人乳腺癌MCF-7细胞随机分为正常组、低氧组以及0.2、0.4、0.8μg/mL竹叶提取物组和0.8μg/mL竹叶提取物组+IGF-1组。CCK-8法检测各组细胞的增殖活性变化,RT-PCR和Western blot检测细胞增殖标记蛋白PCNA、Ki-67和MCM2表达,流式细胞术检测细胞周期和细胞凋亡变化。Western blot检测凋亡相关蛋白Bax、Bcl-2、caspase-3和survivin表达;并探讨Akt/HIF-1α通路在竹叶提取物抑制癌细胞生长中的作用。结果竹叶提取物处理后,低氧下MCF-7细胞的增殖活性和PCNA、Ki-67和MCM2的表达显著性降低并呈现剂量依赖性(P<0.01);而细胞G2/M期比例增加(P<0.01);此外,竹叶提取物处理后细胞凋亡率明显增加,同时Bax和caspase-3表达上调,Bcl-2和survivin表达下调(P<0.01);此外,竹叶提取物组Akt/HIF-1α通路中p-Akt和HIF-1α的表达下调(P<0.01),Akt/HIF-1α通路激动剂IGF-1可逆转竹叶提取物对低氧下MCF-7恶性生长的抑制作用。结论竹叶提取物可通过下调Akt/HIF-1α信号通路抑制低氧条件下人乳腺癌MCF-7细胞恶性生长。

关键词：竹叶提取物 MCF-7 增殖凋亡低氧 Akt/HIF-1α通路 Bax Bcl-2 caspase-3

Distribution and mapping of temperate savanna in the sandy lands of eastern China

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Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN qi LU Institute of Ecological Conservation and Restoration Institute of Desertification Studies Chinese Academy of Forestry Institute of Desertification Institute of Desertification Studies Chinese Academy of Forestry Institute of Great Green Wall Satellite Application Centre for Ecology and Environment MEE Institute of Microelectronics Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences Institute of Forest Resource Information Techniques Chinese Academy of Forestry

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution （VHR） unmanned aerial vehicle （UAV） and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover （FWVC） and fractional herbaceous vegetation cover （FHVC） in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error （RMSE） values for the FWVC and FHVC models were 10.69% and 11.67%,and the R2values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10～6 *** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

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