Among the common hazards related to alluvial fans,flooding is one of the most important.Nonetheless,in populated alluvial fans,not only the natural processes are effective in floods,but the artificial structures and m...Among the common hazards related to alluvial fans,flooding is one of the most important.Nonetheless,in populated alluvial fans,not only the natural processes are effective in floods,but the artificial structures and modifications can change the behavior of flooding and its potential risks.This study aims to indicate the flood-prone landforms in a set of populated alluvial fans in an arid region and investigate the role of anthropogenic activities in controlling/exacerbating flooding in alluvial fans.To achieve this goal,15 Ground Range Detected in High resolution(GRDH)SAR Sentinel-1 images,covering a total of 24 alluvial fans,were acquired.Pre-processing and post-processing steps were applied to all images to identify flood-prone sections of the studied alluvial fans.The results showed that feeder channels,spreading sites,and wide interfluves are the most flood-prone landforms of alluvial fans.In terms of anthropogenic modifications to mitigate flooding,a rampart system is distributed in the study area.Ramparts are levee like structures formed from the fan material.They aim to mitigate flood hazard on residential areas,infrastructures,and agricultural lands of the study area.Results show that the rampart system can reduce the danger of floods,but it cannot be considered a long-term solution.Therefore,a comprehensive flood protection system distributed throughout the whole alluvial fan system is needed.Results also reveal that in regions where flood monitoring is challenging,SAR images can be used as a freely available data set to monitor and identify flooding hotspots.展开更多
中科院仪器设备共享管理平台(Apparatus and Equipment Sharing Management Platform of Chinese Academy of Sciences,以下简称SAMP)在通信过程中,存在重要数据在传输时没有加密、可能会接收到第三方恶意数据等数据通信安全问题,导致S...中科院仪器设备共享管理平台(Apparatus and Equipment Sharing Management Platform of Chinese Academy of Sciences,以下简称SAMP)在通信过程中,存在重要数据在传输时没有加密、可能会接收到第三方恶意数据等数据通信安全问题,导致SAMP系统可能存在数据被窃取、收到的数据不安全等威胁.针对这些问题,结合SAMP系统的特点以及其通信数据的特征,将基于Axis2 Rampart模块的WS-Security数字签名和加密技术应用于SAMP数据通信安全问题.本文首先简单介绍了Axis2框架、数字签名和加密技术、Axis2 Rampart模块加密原理,然后基于Axis2 Rampart模块,采用数字签名+口令+非对称加密的WS-Security通信安全方案,对SAMP系统网络之间的数据传输接口进行封装,实现了消息传输的签名、认证和加密、解密过程,最后测试并分析对比了使用安全方案前和使用安全方案后,SAMP的Web Services数据传输接口的响应处理时间和CPU占用率.实验结果表明:使用Axis2 Rampart模块+数字签名+口令+加密来保证SAMP系统的数据通信安全问题具有高安全性、高可扩展性和高响应处理速度,符合实际应用需求,也能够广泛的推广到其他企业Web应用中去.展开更多
文摘Among the common hazards related to alluvial fans,flooding is one of the most important.Nonetheless,in populated alluvial fans,not only the natural processes are effective in floods,but the artificial structures and modifications can change the behavior of flooding and its potential risks.This study aims to indicate the flood-prone landforms in a set of populated alluvial fans in an arid region and investigate the role of anthropogenic activities in controlling/exacerbating flooding in alluvial fans.To achieve this goal,15 Ground Range Detected in High resolution(GRDH)SAR Sentinel-1 images,covering a total of 24 alluvial fans,were acquired.Pre-processing and post-processing steps were applied to all images to identify flood-prone sections of the studied alluvial fans.The results showed that feeder channels,spreading sites,and wide interfluves are the most flood-prone landforms of alluvial fans.In terms of anthropogenic modifications to mitigate flooding,a rampart system is distributed in the study area.Ramparts are levee like structures formed from the fan material.They aim to mitigate flood hazard on residential areas,infrastructures,and agricultural lands of the study area.Results show that the rampart system can reduce the danger of floods,but it cannot be considered a long-term solution.Therefore,a comprehensive flood protection system distributed throughout the whole alluvial fan system is needed.Results also reveal that in regions where flood monitoring is challenging,SAR images can be used as a freely available data set to monitor and identify flooding hotspots.
文摘中科院仪器设备共享管理平台(Apparatus and Equipment Sharing Management Platform of Chinese Academy of Sciences,以下简称SAMP)在通信过程中,存在重要数据在传输时没有加密、可能会接收到第三方恶意数据等数据通信安全问题,导致SAMP系统可能存在数据被窃取、收到的数据不安全等威胁.针对这些问题,结合SAMP系统的特点以及其通信数据的特征,将基于Axis2 Rampart模块的WS-Security数字签名和加密技术应用于SAMP数据通信安全问题.本文首先简单介绍了Axis2框架、数字签名和加密技术、Axis2 Rampart模块加密原理,然后基于Axis2 Rampart模块,采用数字签名+口令+非对称加密的WS-Security通信安全方案,对SAMP系统网络之间的数据传输接口进行封装,实现了消息传输的签名、认证和加密、解密过程,最后测试并分析对比了使用安全方案前和使用安全方案后,SAMP的Web Services数据传输接口的响应处理时间和CPU占用率.实验结果表明:使用Axis2 Rampart模块+数字签名+口令+加密来保证SAMP系统的数据通信安全问题具有高安全性、高可扩展性和高响应处理速度,符合实际应用需求,也能够广泛的推广到其他企业Web应用中去.
