Numerical and experimental investigations on the band-gap characteristics of metamaterial multi-span beams

A novel metamaterial multi-span beam with periodic simple supports and local resonators is designed and investigated. The frequency responses of the proposed metamaterial multi-span beam are computed by the spectral element method (SEM). The accuracy and feasibility of the SEM are verified by the finite element method (FEM) and the vibration experiments. The results show that the metamaterial multi-span beam could generate both the local resonance band-gaps in the low-frequency ranges and the Bragg band-gaps in the medium and high frequency regions. By adjusting the natural frequencies of the local resonators, the thickness of the base beam and the length of the unit-cell, the local resonance and the Bragg band-gaps can be controlled, respectively. The coupling effects of these two kinds of band-gaps are investigated by the parametrical design, which broadens the band-gaps and consequently improves the vibration reduction performance.     

区域水资源可持续利用综合评价模型的构建及其应用——以哈尔滨市为例

针对区域水资源利用的现状及特点,构建影响区域水资源可持续利用的主要评价指标体系.运用基于实数编码的加速遗传算法(RAGA)的投影寻踪分类(PPC)模型,把多维评价指标值转化为一维投影值,获得指标体系最佳投影方向和投影值,从而做出判断.以哈尔滨市为例,对哈尔滨市区域水资源可持续利用程度进行综合评价,将评价结果与多目标决策的灰色关联投影法的评价结果进行对比,验证了该模型在该方面研究的科学性和有效性.     

基于综合模拟法与支持向量机的水资源预警分析

提出并确定了哈尔滨市水资源可持续利用预警指标的警度.利用反馈法确定了预警指标的警限,采用2次检验的方法对其预警有效性进行了检验,设计了预警信号灯系统,并对哈尔滨市水资源可持续利用进行监测预警;运用支持向量机的方法预警指标值进行预测,对哈尔滨市水资源可持续利用进行趋势预警,包括单指标趋势预警和多指标趋势预警,进而获得了趋势预警的结果.     

基于极大熵投影寻踪组合法的水资源预警评价模型

利用基于极大熵准则赋权和基于实数加速遗传算法的投影寻踪方法相结合的组合附权法确定了各预警指标的权重;采用层次分析法计算水资源可持续利用复合系统中各子系统所占权重;利用综合评价模型计算出哈尔滨市水资源可持续发展指数;最终得到哈尔滨市水资源可持续利用预警结果.