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基于具有对称生成元正交小波的图象重构算法
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作者 刘一武 张邦礼 王光学 《重庆大学学报(自然科学版)》 EI CAS CSCD 1998年第5期30-34,共5页
针对具有对称生成元的正交小波基,利用其正交镜象滤波器的性质,提出了一种新的图象重构算法。理论分析和计算机仿真结果表明,本算法不但显著地提高了图象重构运算的速度,并且使图象重构的质量也得到一定的改善。
关键词 图象变换 滤波器 算法 正交小波 对称生成元
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热方程的非古典势对称群与不变解 被引量:2
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作者 秦茂昌 梅凤翔 许学军 《应用数学和力学》 CSCD 北大核心 2006年第2期217-222,共6页
主要研究了热方程与波方程的非古典势对称群生成元及相应的群不变解.研究表明对于守恒形式的偏微分方程,可通过其伴随系统求得的非古典势对称群生成元来构造其显式解.这些显式解不能由方程本身的Lie对称群生成元或Lie_Backlund对称群生... 主要研究了热方程与波方程的非古典势对称群生成元及相应的群不变解.研究表明对于守恒形式的偏微分方程,可通过其伴随系统求得的非古典势对称群生成元来构造其显式解.这些显式解不能由方程本身的Lie对称群生成元或Lie_Backlund对称群生成元构造得到. 展开更多
关键词 非古典势对称生成 热方程 波方程 显式解
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Asymmetric or diffusive co-evolution generates meta-populations in fig-fig wasp mutualisms
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作者 WANG RuiWu YANG Yan WIGGINS Natasha L. 《Science China(Life Sciences)》 SCIE CAS 2014年第6期596-602,共7页
Co-evolutionary theory assumes co-adapted characteristics are a positive response to counter those of another species,whereby co-evolved species reach an evolutionarily stable interaction through bilateral adaptation.... Co-evolutionary theory assumes co-adapted characteristics are a positive response to counter those of another species,whereby co-evolved species reach an evolutionarily stable interaction through bilateral adaptation.However,evidence from the fig-fig wasp mutualistic system implies very different co-evolutionary selection mechanisms,due to the inherent conflict among interacted partners.Fig plants appear to have discriminatively enforced fig wasps to evolve"adaptation characteristics"that provide greater benefit to the fig,and fig wasps appear to have diversified their evolutionary strategies in response to discriminative enforcement by figs and competition among different fig wasp species.In what appears to be an asymmetric interaction,the prosperity of cooperative pollinating wasps should inevitably lead to population increases of parasitic individuals,thus resulting in localized extinctions of pollinating wasps.In response,the sanctioning of parasitic wasps by the fig should lead to a reduction in the parasitic wasp population.The meta-populations created by such asymmetric interactions may result in each population of coevolved species chaotically oscillated,temporally or evolutionarily. 展开更多
关键词 asymmetric co-evolution inter-specific cooperation META-POPULATION MUTUALISM
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