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51.
数据流具有快速性、连续性、多变性及无限性等特性,使得传统的分类方法不再适用。由于数据流多变的特性,设计高效、高精度的分类算法是比较困难的。目前数据流在电信、网络等众多应用领域客观大量存在,因此研究快速的、精确的、稳定的数据流分类系统具有较高的理论价值和应用前景。近年来,大量的研究工作都旨在高效准确地解决隐含概念漂移的数据流的分类问题。本文研究了一些适合数据流的分类算法,根据算法主要思想的不同进行分类,根据每种思想的发展历程对其相应的算法进行论述,并对部分经典算法分析其处理概念漂移的性能,并对进一步可做的工作进行展望。 相似文献
52.
通过对单级多项目无能力约束生产批量问题(SMULP)模型进行分析,得出了一些重要的结论.分析了基本遗传算法的缺陷及其产生的原因.对该问题在遗传算法的编码、适应度函数、选择复制操作、交叉方法、交叉概率、变异概率和终止条件等各个环节进行了改进.采用VB6.0对SMULP改进遗传算法编程实现,能很好地与ERP软件集成.并对SMULP改进遗传算法进行了性能分析. 相似文献
53.
用逐次逼近法求解北半球斜上抛体问题 总被引:1,自引:1,他引:0
运用逐次逼近理论,给出了在北半球斜上抛体的三次近似解. 相似文献
54.
Hideki Ueno 《Researches on Population Ecology》1994,36(1):121-124
Heritabilities and genetic correlations for body size characters and development period in a coccinellid beetle,Harmonia axyridis were estimated by a sib-analysis experiment. Positive genetic correlations were detected between size characters and development
rate. If this is upheld in the field, genetic variation would be eliminated, as the loci affecting the characters are supposed
to be fixed. However, the results indicated moderate heritabilities for all characters. Possible explanations for the results
are discussed. 相似文献
55.
Susan M. Cox 《Qualitative sociology》2003,26(2):257-280
Huntington Disease (HD) is a hereditary neurological disease that typically occurs in mid-life. There is no prevention or cure, but persons at risk may request predictive genetic testing to learn whether or not they will develop the disease later in life. Many studies describe why such persons request this knowledge. Few consider how people actually make this novel decision. Drawing on in-depth interviews with sixteen test candidates, this article differentiates three types of stories about—as well as embedded in—the experience of deciding. Each type of story sheds a different light on the meaning and experience of making this decision. Stories of having to know reveal that decision-making may be experienced as a self-evident act while stories of evolving toward it feature an incremental process of weighing up the implications. Stories of taking the decision feature a pivotal point which involves the narrator in seeing anew the opportunity to make a choice. Emphasizing previously neglected temporal, biographical and phenomenological dimensions of decision-making, this typology underscores the relevance of narrative in complex processes of decision-making. It also illustrates the inadequacy of understanding decision-making purely through the lens of rational choice. 相似文献
56.
57.
粒子群优化算法是根据鸟群觅食过程中的迁徙和群集模型而提出的用于解决优化问题。该文讨论粒子群优化算法的基本原理和实现步骤,分析了该算法中各参数的设置。通过一个测试函数,对粒子群优化算法与遗传算法进行了比较,结果表明粒子群优化算法在找寻最优解效率上好于遗传算法。 相似文献
58.
谢维营 《烟台大学学报(哲学社会科学版)》2006,19(4):371-376
道德与利益虽然有矛盾,但从根本上来说应该是内在一致的,任何道德规范中都蕴涵着利益机制,道德规范归根结底是对利益的调整,因此,道德总是反映着一定社会历史时期人们之间的特定利益关系。其中,经济利益机制的选择决定着某一种道德在某种阶级中的认可和实行程度;政治利益的结构和格局是该社会道德的表率和核心;文化利益的日益显性化使道德的最后一层外衣被无情剥去。道德的沿革和进步既是利益调整的需要,也是利益调整的结果。从道德的变迁中可以发现利益调整的轨迹。 相似文献
59.
The deme formation hypothesis in herbivorous insects states that herbivores differentiate genetically into small demes, each
specialized in the idiosyncratic traits of individual plants. We examined this hypothesis in gall-forming aphids,Adelges japonicus, by reciprocal transfers of aphids among three susceptible clones ofPicea jezoensis standing in proximity. Performance of aphids transferred to their natal clone was compared with that of aphids transferred
to other novel clones. ANCOVA showed no significant donor (source of aphids) by receptor (recipient of aphids) interactions
for both total aphid performance on the host tree over a life cycle and its three subdivisions(q
1,q
2 andq
3). In addition, the total performance on the natal clone was lowest among those in the three clones, which was explicitly
against the prediction from the local adaptation. In contrast, there were significant receptor effects onq
1 (fecundity of gallicolae multiplied by survivorship of fundatrices while feeding on needles) andq
3 (fecundity of fundatrices multiplied by survivorship of gallicolae before emergence from the galls), suggesting genetic differences
in resistance among clones. The two-fold difference inq
3 among clones was due to different gall size, which was highly correlated with the number of gallicolae that emerged from
the gall. The two-fold difference inq
1 seemed to be caused by different survivorship of larval fundatrices while feeding on needles. 相似文献
60.
唐丽 《西南农业大学学报(社会科学版)》2004,2(4):113-116
概述了基因工程在国内外林木培育中的应用现状及发展趋势 ,综述了我国十多年来林木在抗虫、抗病、抗逆境、品质改良、育性等基因工程的研究与应用研究取得的一些进展及今后的发展方向。 相似文献