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一种新的基于类内不平衡数据学习支持向量机算法 被引量:2
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作者 梁武 苏燕 《科技通报》 北大核心 2017年第9期109-112,共4页
本文以不平衡支持向量机算法为基础,有效应用以往样本集中类内结构信息数据,重点对不平衡数据集进行研究和分析,并提出新的不平衡支持向量机算法,新的算法以类内离散度为基础,仿真实验数据结果证明,经过改进的算法非常有效,可进一步提升... 本文以不平衡支持向量机算法为基础,有效应用以往样本集中类内结构信息数据,重点对不平衡数据集进行研究和分析,并提出新的不平衡支持向量机算法,新的算法以类内离散度为基础,仿真实验数据结果证明,经过改进的算法非常有效,可进一步提升G-means值和SE值。 展开更多
关键词 不平衡数据 支持向量机算法 离散度 类内结构
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Relationships between bird communities and vegetation structure in Honghuaerji, northern Inner Mongolia 被引量:2
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作者 王文 丸山直树 +2 位作者 刘伯文 森本英人 高中信 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期294-298,337,共5页
The survey on bird communities was conducted by the belt-style method in six different sample plots in the Honghua抏rji Forests area in the northern Inner Mongolia in June 2001 and totally 28 bird species were recorde... The survey on bird communities was conducted by the belt-style method in six different sample plots in the Honghua抏rji Forests area in the northern Inner Mongolia in June 2001 and totally 28 bird species were recorded. Vegetation investigation was carried out in five 10 m×10 m quadrats at each plot. The asymptotic regression function formulae were adopted to identify the relationships between the vegetation coverage and the numbers of bird species and individuals. The analytical results showed that the changes of species number and density of bird as well as the formation of bird communities follow the changes of forest type and the total foliage. Both the number of bird species and their density decreased with the de-crease of total foliage. The similarity of bird community was very low at the breeding time. In the same classification of cluster, no similarity was higher than 0.65, which indicated that the composition of species had a great difference between all the bird communities. The bird breeding density was closely related to forest growth stage. From the bare grassland ecosystem to cli-max ecosystem, the density of bird species showed a gradually increasing trend. 展开更多
关键词 Bird community Vegetation structure Honghua抏rji Northern Inner Mongolia
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