排序方式: 共有47条查询结果,搜索用时 218 毫秒
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1IntroductionNowadays,asthenaturalresourcesbecomemoreandmorelimitedtotheeconomicdevelopmentintheworld,themanagementofhumanbeh... 相似文献
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尾矿坝浸润线时空混沌及其安全机理 总被引:1,自引:0,他引:1
在单向耦合映象格子模型基础上,考虑尾矿坝坡角因素,建立了浸润线耦合映象格子模型vn 1(i)=(1-ε)f(vn(i)) ε(1 sinθ)f(vn(i-1)).根据浸润线的初值条件和边界条件,对该模型进行了非线性动力学分析.结果表明,浸润线演化存在复杂时空混沌行为,可分为随机图样流、选择图样流、缺陷传播行为及完全发展湍流4种.非线性强度α和耦合强度ε的取值范围较小, 且ε较小时就可以得到非常丰富的动力学图案.浸润线演化受坡角影响比较明显,坡角越大越容易出现混沌状态.浸润线的各种时空行为反映了其相应的客观状态,从而揭示了浸润线的安全机理.浸润线耦合映象格子模型也可以用来解释其他各类边坡的复杂渗流现象. 相似文献
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Gilgan M 《Disasters》2001,25(1):1-18
The different conceptualisations of conflict in the complex emergency literature have profound implications on the perception of the agency of different groups and the prospects for conflict management. While much recent analysis has focused on the rational political and economic functions of violence, relatively little analysis has focused on why the majority of people chose not to resort to violence. Using Foucault's analysis of power relations, a new framework for conflict analysis is proposed which includes non-violent resistance as well as violence as a means of domination. Non-violent resistance is explored as a rational, highly adaptable response to acts of domination. A comprehensive understanding of conflict must recognise local forms of resistance and identify the barriers and opportunities for the engagement of the international humanitarian community with these groups. This engagement can be used to foster capacities for the creation of legitimate, inclusive, non-violent political and economic processes in the attempt to provide alternatives for everyone in the conflict. If the purpose of the study of complex emergencies is to understand the nature of various conflicts and, based on that understanding, make recommendations for possible routes to conflict management, the analysis of local resistance and efforts to foster it must become a major aspect of the research agenda. 相似文献
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基于相空间重构理论的天津市近海水质混沌特性研究 总被引:1,自引:0,他引:1
针对我国近海水质污染呈现的复杂非线性特征,通过对混沌理论中的相空间重构方法进行研究,提出了一种新的完全基于环境监测数据的近海水质分析方法。以天津市近岸海域为例,首先,根据相空间重构理论,对近海各监测点的1维COD时间序列进行多维相空间重构,求得最佳嵌入维数mmin和吸引子关联维数D;然后,采用Wolf方法计算最佳嵌入维数mmin下重构相空间的最大Lyapunov指数λ1。计算结果显示各个监测点的关联维数D均在3.3左右,最大Lyapunov指数λ1均大于0,表明近海水质COD时间序列具有明显的混沌特征,近海水质系统是一个多维系统,貌似随机无规律的近海水质系统具有内在的、固有的规律。应用表明,该方法实用性强,为进一步采用混沌理论对近海水质进行预测提供了理论依据,非常有利于近海水环境的管理。 相似文献
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变尺度混沌-遗传算法在复杂河流水质模型参数优化中的应用 总被引:5,自引:0,他引:5
将变尺度混沌-遗传算法(MSCGA)应用于复杂河流水质模型参数优化.采用湘江衡阳段水质监测资料,以二维河流水质数学模型反演结果的均方误差为适应度函数,估计横向扩散系数Dx、纵向弥散系数Dy和污染物衰减系数κ.数值实验结果表明,MSCGA寻优过程具有明显的分级特征,级级收敛;在同样的条件下,MSCGA的收敛速度较快,为遗传算法(GA)的1.36倍;同时,MSCGA克服了GA早熟收敛的问题,其最优适应度函数值为7.6×10-4,而GA的最优适应度函数值9.6×10-4.将MSCGA应用于研究河段,求得Dx、Dy分别为0.1335、0.0011,BOD5、As、Cr的衰减系数κ分别为0.0229、0.0100、0.0107. 相似文献