Based on monthly runoff and climate datasets spanning 2000–2024,this study employed the Theil–Sen’s slope estimation,Mann–Kendall(M–K)trend test,as well as Pearson correlation and Spearman rank correlation analys...Based on monthly runoff and climate datasets spanning 2000–2024,this study employed the Theil–Sen’s slope estimation,Mann–Kendall(M–K)trend test,as well as Pearson correlation and Spearman rank correlation analyses to systematically examine the spatiotemporal patterns of runoff and its climatic driving mechanisms across Tajikistan,providing a scientific basis for sustainable water resource utilization and management in the study area.Results indicated that during 2000–2024,the annual runoff in Tajikistan exhibited statistically non-significant long-term trend(P=0.76),while displaying pronounced seasonal variability and strong spatial heterogeneity.Spring and summer average runoff primarily exhibited slight declining tendencies,while winter average runoff exhibited pronounced reduction in localized regions,such as the Syr Darya Basin,the Vakhsh River Basin,and the lower reaches of the Zeravshan River Basin.Precipitation emerged as the dominant positive driver of runoff,exhibiting moderate to strong positive correlations across over 78.00%of the country,whereas potential evapotranspiration consistently functioned as a negative driver.Rising temperatures exerted a dual competitive effect on runoff:in high-elevation,glacier-covered regions,rising temperatures temporarily increased runoff by accelerating glacier melt;however,at the national scale,the negative impact of rising temperature on runoff has played a slightly dominant role to a certain extent by enhancing evapotranspiration.Collectively,these results indicated that the present stability of runoff in Tajikistan is strongly dependent on the short-term compensatory effects of glacier melt and the risk of future runoff decline is likely to intensify as glacier reserves continue to diminish.This study provides a critical scientific evidence to inform sustainable water resource management in Tajikistan and underscores the need for glacier conservation and integrated water resource management strategies.展开更多
从攻击者的角度探讨信息物理系统(Cyber-physical system,CPS)中隐蔽虚假数据注入(False data injection,FDI)攻击的最优策略.选取Kullback-Leibler(K-L)散度作为攻击隐蔽性的评价指标,设计攻击信号使得攻击保持隐蔽且最大程度地降低CP...从攻击者的角度探讨信息物理系统(Cyber-physical system,CPS)中隐蔽虚假数据注入(False data injection,FDI)攻击的最优策略.选取Kullback-Leibler(K-L)散度作为攻击隐蔽性的评价指标,设计攻击信号使得攻击保持隐蔽且最大程度地降低CPS远程状态估计的性能.首先,利用残差的统计特征计算远程状态估计误差协方差,将FDI最优策略问题转化为二次约束优化问题.其次,在攻击隐蔽性的约束下,运用拉格朗日乘子法及半正定规划推导出最优策略.最后,通过仿真实验验证所提方法与现有方法相比在隐蔽性方面具有显著优势.展开更多
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0720203)the National Key Research and Development Program of China(2023YFF0805603).
文摘Based on monthly runoff and climate datasets spanning 2000–2024,this study employed the Theil–Sen’s slope estimation,Mann–Kendall(M–K)trend test,as well as Pearson correlation and Spearman rank correlation analyses to systematically examine the spatiotemporal patterns of runoff and its climatic driving mechanisms across Tajikistan,providing a scientific basis for sustainable water resource utilization and management in the study area.Results indicated that during 2000–2024,the annual runoff in Tajikistan exhibited statistically non-significant long-term trend(P=0.76),while displaying pronounced seasonal variability and strong spatial heterogeneity.Spring and summer average runoff primarily exhibited slight declining tendencies,while winter average runoff exhibited pronounced reduction in localized regions,such as the Syr Darya Basin,the Vakhsh River Basin,and the lower reaches of the Zeravshan River Basin.Precipitation emerged as the dominant positive driver of runoff,exhibiting moderate to strong positive correlations across over 78.00%of the country,whereas potential evapotranspiration consistently functioned as a negative driver.Rising temperatures exerted a dual competitive effect on runoff:in high-elevation,glacier-covered regions,rising temperatures temporarily increased runoff by accelerating glacier melt;however,at the national scale,the negative impact of rising temperature on runoff has played a slightly dominant role to a certain extent by enhancing evapotranspiration.Collectively,these results indicated that the present stability of runoff in Tajikistan is strongly dependent on the short-term compensatory effects of glacier melt and the risk of future runoff decline is likely to intensify as glacier reserves continue to diminish.This study provides a critical scientific evidence to inform sustainable water resource management in Tajikistan and underscores the need for glacier conservation and integrated water resource management strategies.
文摘从攻击者的角度探讨信息物理系统(Cyber-physical system,CPS)中隐蔽虚假数据注入(False data injection,FDI)攻击的最优策略.选取Kullback-Leibler(K-L)散度作为攻击隐蔽性的评价指标,设计攻击信号使得攻击保持隐蔽且最大程度地降低CPS远程状态估计的性能.首先,利用残差的统计特征计算远程状态估计误差协方差,将FDI最优策略问题转化为二次约束优化问题.其次,在攻击隐蔽性的约束下,运用拉格朗日乘子法及半正定规划推导出最优策略.最后,通过仿真实验验证所提方法与现有方法相比在隐蔽性方面具有显著优势.
