When central populations exhibit more genetic diversity than peripheral populations: A simulation study

The central-peripheral population hypothesis (CPH) predicts that peripheral populations have reduced genetic variability. Therefore, it is often assumed that they deserve higher conservation priority over central populations. We examined this hypothesis using computer simulations with the objective of determining the range of species properties (parameters) under which a species is likely to exhibit the CPH pattern. The interaction between migration, genetic drift, and time of population establishment was e...     

An adaptive spatial clustering method for automatic brain MR image segmentation

In this paper, an adaptive spatial clustering method is presented for automatic brain MR image segmentation, which is based on a competitive learning algorithm – self-organizing map (SOM). We use a pattern recognition approach in terms of feature generation and classifier design. Firstly, a multi-dimensional feature vector is constructed using local spatial information. Then, an adaptive spatial growing hierarchical SOM (ASGHSOM) is proposed as the classifier, which is an extension of SOM, fusing multi-scale segmentation with the competitive learning clustering algorithm to overcome the problem of overlapping grey-scale intensities on boundary regions. Furthermore, an adaptive spatial distance is integrated with ASGHSOM, in which local spatial information is considered in the clustering process to reduce the noise effect and the classification ambiguity. Our proposed method is validated by extensive experiments using both simulated and real MR data with varying noise level, and is compared with the state-of-the-art algorithms.     

论陡河发电厂污水处理现状及发展方向

文章对陡河发电厂目前污水的来源及处理方式进行了介绍,并且对主系统改造后污水处理的发展方向给予论述.     

诱导信息条件下车辆路径选择——基于有限理性模糊博弈

诱导信息属于建议性信息,当诱导信息发布以后驾驶员并不一定接受诱导信息;在行为强化理论基础上,建立了基于有限理性模糊博弈的诱导信息条件下车辆路径选择模型,并通过仿真得出了不同初始状态下的博弈平衡结果;仿真结果表明:诱导信息的发布并不一定能改善路网交通流分布,它与路网总流量以及初始接受诱导的车辆比例密切相关.     

大跨空间结构振动抑制的阻尼器优化布置

提出适宜的适应度函数,将遗传算法的种群思想引入模拟退火算法中,构造出遗传算法与模拟退火算法的组合算法,用于空间结构振动抑制的阻尼器位置和数量寻优。通过空间网壳在不同冲击荷载作用下的算例分析发现,若设置合适的控制参数,运用组合算法可迅速准确地找到全局最优解方案。     

嶂石岩蜘蛛群落种类组成的研究

对１９７９～１９８２年采自嶂石岩现存在下河北师范大生物系土壤动物研究室的５８６头蜘蛛标本进行了整理鉴定，共定出１８科６９属１２０种，此结果可以作为河北省西南部山林蜘蛛群落种类组成的典型代表。     

n-球面上Cesàro算子的强求和(英文)

设f是Rn中的单位球面上的可积函数（X≥3），σ（f）是f的Fourier-Laplace级数，表示σ（f）的δ阶Cesaro平均．对于q∈（0，2]，当时．rier-Laplace级数，表示σ（f）的δ阶Cesaro平均，对于q∈（0，2]有     

浅谈洛阳出土文物的艺术魅力

阐述了洛阳历代出土铜镜、陶俑、三彩俑巧妙的造型艺术构思和精湛的工艺制作技术，从而展现了洛阳出土文物的艺术魅力