动态格点搜索的改进算法用于团簇结构快速优化

结合高效的动态格点搜索(DLS)算法与扰动操作(Perturbation Operation)提出一种新的改进方法(DLS-PO),用于确定团簇的最低能量结构。针对一个特定构型,DLS算法总能给出其对应搜索空间的最规则结构。然而,一次失败的DLS优化将消耗大量的运算资源。为此,采取原子移动和结构旋转的扰动操作成功地改变了构型,再结合后续的DLS操作,提高了优化效率。将该算法用于原子数高达309的Lennard-Jones团簇及100原子NP-B函数铝团簇的结构优化。优化结果显示相比于DLS算法,DLS-PO算法更为高效。     

案例式教学法在《Access数据库》教学中的应用研究

作为一门重要的数据库基础课程,《Access数据库》的教学不但可以使学生学会一种数据库技术,而且还能够奠定学生将来学习高级数据库技术的基础,因此,将案例式教学法应用《Access数据库》教学中具有重大的实际意义。为此,对案例式教学法的内涵进行阐述,《Access数据库》教学中案例式教学法的实际应用策略,以及应用案例式教学法需要注意的一系列事项。     

案例教学方法在《土木工程CAD》教学中的应用

基于对《土木工程CAD》教学中案例教学方法存在的问题的分析,结合《土木工程CAD》课程教学内容,通过精心选择案例,在课堂教学、实训教学和课程考核中应用教学案例,改善课程教学效果。教学实践表明,案例教学方法的应用明确课程的学习内容,激发学生的学习兴趣,保证课程教学效果,提高学生分析和解决问题的能力。     

结合 CDIO 与案例教学的《C 程序设计》教学实践

针对传统《C#程序设计》课程教学不利于计算机专业学生工程能力培养的状况,提出将CDIO教育理念与案例教学相结合的教学模式。该教学模式有效地实现启示知识、启迪思维和培养学生C#应用程序设计能力的目标,取得良好的教学效果．并获得学生普遍的欢迎。     

基于《ASP．NET程序设计》课程的教学改革初探

将案例运用于教学,可以提高学生的学习兴趣,教学效果良好。但很难将要求掌握的知识点放置于某个案例中．或者说一个案例不可能囊括所有的知识点。所以,如何选用某些典型案例,并将案例分解成一个个的“任务”,成了案例教学中的难点。以Web新闻发布系统为例,对案例任务教学进行一些尝试。     

案例教学法在《大学计算机基础》课程教学中的应用

通过对《大学计算机基础》教学现状及存在的问题进行分析,探讨一种与传统教学方法不同的新型教学方法,即案例教学法。重点研究如何有效地把案例教学方法应用到教学中,从而提高教学效率。实践证明案例教学法是一种有效的教学方法．有利于培养学生的学习兴趣和动手能力,能取得良好的教学效果。     

Host microhabitat location by stem-borer parasitoidCotesia flavipes: the role of herbivore volatiles and locally and systemically induced plant volatiles

The origin of olfactory stimuli involved in the host microhabitat location inCotesia flavipes, a parasitoid of stem-borer larvae, was investigated in a Y-tube olfactometer. The response of femaleC. flavipes towards different components of the plant-host complex, consisting of a maize plant infested with two or more larvae of the stem borerChilo partellus, was tested in dualchoice tests. The concealed lifestyle of the stem-borer larvae did not limit the emission of volatiles attractive to a parasitoid. A major source of the attractive volatiles from the plant-host complex was the stem-borer-injured stem, including the frass produced by the feeding larvae. Moreover, the production of volatiles attractive to a parasitoid was not restricted to the infested stem part but occurs systemically throughout the plant. The uninfested leaves of a stem-borer-infested plant were found to emit volatiles that attract femaleC. flavipes. We further demonstrate that an exogenous elicitor of this systemic plant response is situated in the regurgitate of a stem-borer larva. When a minor amount of regurgitate is inoculated into the stem of an uninfested plant, the leaves of the treated plant emit volatiles that attract femaleC. flavipes.     

基于分类外形搜索的人脸特征点定位

针对传统由粗糙到精准的人脸外形搜索方法,其每一次外形搜索需要在整个外形搜索空间进行,提出一种基于分类的外形搜索方法。该方法始于一个包含不同人脸形状的外形搜索空间,首先利用基于相关性的特征选择方法对随机森林分类器进行优化,利用训练的随机森林分类器将外形搜索空间分为若干个外形搜索子空间;然后根据输入样本和随机森林分类器确定与当前外形最接近的外形搜索子空间,并计算对应子空间的中心和对应样本的后验概率分布,方便后续阶段更好地进行外形搜索;最后采用级联回归进行人脸特征点定位。在300-W数据集上的实验结果表明,此方法不仅有效降低了外形搜索的时间,同时在无约束环境中具有良好的鲁棒性。     

多交叉混沌选择反向小生境遗传算法

为提高小生境遗传算法的全局以及局部搜索能力,提出一种多交叉混沌选择反向小生境遗传算法。利用分段线性混沌映射函数生成一组混沌数序列,在每次进行交叉操作前,依据序列中对应元素的数值大小选择不同的交叉算子进行操作,通过小生境遗传算法产生较优的子代种群。针对子代种群,应用反向搜索策略获得反向种群,在子代种群和反向种群中进行精英选择得到最终新种群,以进一步加强算法的局部寻优能力。仿真实验结果表明,该算法在最优解及均值方面好于小生境遗传算法,从而证明其可行性和优越性。     

Misleading the Colorado potato beetle with an odor blend

Walking tracks of Colorado potato beetles,Leptinotarsa decemlineata Say, were recorded on a locomotion-compensator in response to wind, odors of host plantsSolanum tuberosum L. and nonhost plantsLycopersicon hirsutum f.glabratum C.H. Mull, and to mixtures of these plant species. Host-plant odor induced positive anemotactic responses in starved females, whereas odor of the nonhostL. hirsutum was neither repellent nor attractive. The attractiveness of host-plant odor, however, was neutralized in the odor blend of plant species. Masking the attractive host-plant odor will hinder the beetle's searching for host-plant patches, and this principle may be exploited in pest control by mixed cropping.The locomotion-compensator was constructed with financial support from the Foundation for Fundamental Biological Research (BION), which is subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO), grant 14-02-02. The first author was supported by a grant from the French Ministry of Industry and Research.