基于AdaBoost改进随机森林和SVM的 极化SAR地物分类     

张政  李世强 《中国科学院大学学报》2022,39(6):776-782

为提升极化合成孔径雷达(SAR)地物分类精度,提出一种基于AdaBoost改进型随机森林和支持向量机(SVM)结合的二级分类结构。首先将AdaBoost改进型随机森林作为初级分类器,该分类器能根据决策树的分类能力赋予权重,分类能力越强则权重越高,从而提升初级分类精度。初级分类器还能评估输入特征的重要性,获得重要性排名。根据重要性排名进行特征筛选,用筛选后的特征训练SVM分类器,获取二级分类结果。最后利用邻域投票法将两级分类结果融合。AIRSAR极化数据对比实验表明,该分类结构可有效提升极化SAR地物分类精度。  相似文献   

基于改进遗传算法的图像相关匹配     

孙国玺 《茂名学院学报》2006,16(1):37-39

针对图像匹配的数学特点,设计一种新的改进遗传算法用于相关图像匹配。根据基因位的影响和参数调整策略,采用半确定性和大变异结合,汉明距离控制的方法。仿真结果表明,新算法在收敛性能上大大优于简单遗传算法和经典序列猜测算法。  相似文献   

过渡时期高职院校图书馆应解决的几个问题   总被引：1，自引：0，他引：1  

薛原  郭云卿 《邢台职业技术学院学报》2006,23(1):89-90

本文就高等职业技术院校图书馆在过渡时期存在的有关问题进行探讨,并提出相应的整改措施和方法。  相似文献   

Influence of improved teaching practices on student satisfaction ratings for two undergraduate units at an Australian university     

Barbara Stewart  Peter Speldewinde  Benjamin Ford 《Assessment & Evaluation in Higher Education》2018,43(4):598-611

To track the quality of instruction delivered at the University of Western Australia, the university surveys all units using its Students’ Unit Reflective Feedback (SURF) metrics, and faculties use these metrics to benchmark student satisfaction. Consequently, teaching staff are actively encouraged to adopt teaching practices that will increase the average levels of these metrics. Using a ‘before-after’ approach, we compared these metrics before and after the implementation of improved teaching practices that addressed specific weaknesses identified through student responses for two undergraduate units. Despite the implementation of improved teaching practices, SURF scores did not increase significantly for the two units assessed, due possibly to the components of the academic programme covered by the SURF questions, the field-based nature of the units, and the difficulty in measuring an increase in the SURF scores of units which already score highly. This poor sensitivity of the SURF metrics to the implementation of improved teaching practices could have implications for their use for performance assessment by the university.  相似文献   

一种非线性方程的强非线性共振的转迁集     

许东亮 《新乡师范高等专科学校学报》2007,21(5):4-6

运用多尺度法和改进的L-P方法,通过引入参数变换把较大的摄动参数ε转换成小参数α,从而使讨论的非线性方程可用多尺度法和L-P方法求其近似解。求出了该方程亚谐共振(即k=1/2)时的分岔响应方程和转迁集。  相似文献   

用改进的试探函数法求解广义KdV方程     

谢元喜 《娄底师专学报》2006,(3):13-15

试探函数法求解非线性数学物理中一个非常著名的非线性偏微分方程-广义KdV方程，求得其一般形式的指数函数解，据此不但求得了广义KdV方程的sech^2型钟状正则孤波解，而且求得了其csch^2型奇异行波解，最后，利用一些熟知的数学关系式，又求得其若干其它显式精确解，包括三角函数型周期波解等。  相似文献   

单摆在液体中的振动     

何松林 《实验室研究与探索》2011,30(6)

由摆球浸入不同温度纯水中的小角阻尼振动实验,发现角振幅衰减及振动周期不随液体黏度发生改变。采用改进平均法求解平方阻尼作用下单摆小角振动微分方程,得到角位移随时间变化的解析表达式,据此得到的角振幅衰减及振动周期的定量结果与实验数据符合。得出结论:摆球在液体中振动时受到的流体阻力是与液体黏度无关的平方阻力;平方阻尼常量与液体的密度成正比,与摆球半径及密度的乘积成反比;摆球浸入液体时的阻尼振动、角振幅衰减是非指数型的,衰减速度和振动周期都与平方阻尼常量密切相关。  相似文献   

一种基于分簇无线传感器网络的时间同步技术     

居金娟  姚弘  成行洁 《南通职业大学学报》2011,25(2):72-76

针对无线传感器网络中时间同步技术应具有高效率且节省资源的要求,给出了一种改进算法：使用时间同步有效性检查阶段的时间戳,在只发送一个小数据包的基础上实现同步功能,使所需消息传输量较传统算法少得多,既提高了同步效率,又降低了能源消耗,并兼顾了应用场合的精度要求,仿真结果验证了该方法的有效性。  相似文献   

Progressivism and the History of the Public House, 1850–1950     

《Cultural and Social History》2013,10(2):235-259

ABSTRACT

In a recent article, Alistair Mutch suggests that twin concepts – ‘control’ and ‘interpretation’ – explain the evolution of the public house over a century of dramatic changes between 1850 and 1950. This article argues that these concepts are confusing, ambiguous and misleading. It was not regulatory pressures, the temperance movement, local politicians, pressure groups or magistrates that most shaped the history of drinking premises, but developments outside the brewing industry, most notably Progressivism. Emerging in the late nineteenth century, Progressives set out to reform drinkers and drink premises, first in the trust house movement, and then in the Liquor Traffic Central Control Board during the First World War. Appropriating their ideas and philosophy immediately following the war, England's foremost brewers launched the public house improvement movement, the most far-reaching attempt to transform the nature of public drinking in the twentieth century.  相似文献   

Theories and Evidence     

《Cultural and Social History》2013,10(2):219-226

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