为保护互联网用户在使用网络过程中的个人隐私数据,提出一种基于软件定义网络(software defined network,SDN)和集群思想的匿名通信系统架构,由统一的控制中心对系统内节点进行管理和调配,在短时间内对匿名通信请求做出响应。设计多约...为保护互联网用户在使用网络过程中的个人隐私数据,提出一种基于软件定义网络(software defined network,SDN)和集群思想的匿名通信系统架构,由统一的控制中心对系统内节点进行管理和调配,在短时间内对匿名通信请求做出响应。设计多约束最优路径规划算法,综合考虑节点带宽、在线时长等因素,均衡网络负载,降低路径选择攻击的威胁。通过理论分析和仿真实验可知,该系统在保证通信匿名性的同时,可以在一定程度上抵御合谋攻击、流量分析攻击、时间攻击等主流攻击方式,在同一网络环境下其转发延迟明显低于Tor。展开更多
As a new kind of air-hardening soil reinforcement material,polymer is being widely applied in river-bank slope reinforcement and ecological slope protection area.Thus,more attention should be paid to study the charact...As a new kind of air-hardening soil reinforcement material,polymer is being widely applied in river-bank slope reinforcement and ecological slope protection area.Thus,more attention should be paid to study the characteristics of reinforced soil after immersion.In this study,water-induced changes in strength characteristics of sand reinforced with polymer and fibers were reported.Several factors,including polymer content(1%,2%,3%and 4%by weight of dry sand),immersion time(6,12,24 and 48 h),dry density(1.40,1.45,1.50,1.55 and 1.60 g/cm^(3),)and fiber content(0.2%,0.4%,0.6%and 0.8%by weight of dry sand)which may influence the strength characteristics of reinforced sand after immersion were analyzed.The microstructure of reinforced sand was analyzed with nuclear magnetic resonance(NMR)and scanning electron microscope(SEM).Experimental results indicate that the compressive strength increases with the increase of polymer content and decreases with the increase of immersion time;the softening coefficients decrease with the increase of the polymer content and immersion time and increase with an increment in density and fiber content.Fiber plays an active role in reducing water-induced loss of strength at 0.6%content.展开更多
In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperatu...In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.展开更多
文摘为保护互联网用户在使用网络过程中的个人隐私数据,提出一种基于软件定义网络(software defined network,SDN)和集群思想的匿名通信系统架构,由统一的控制中心对系统内节点进行管理和调配,在短时间内对匿名通信请求做出响应。设计多约束最优路径规划算法,综合考虑节点带宽、在线时长等因素,均衡网络负载,降低路径选择攻击的威胁。通过理论分析和仿真实验可知,该系统在保证通信匿名性的同时,可以在一定程度上抵御合谋攻击、流量分析攻击、时间攻击等主流攻击方式,在同一网络环境下其转发延迟明显低于Tor。
基金Project(41472241)supported by the National Natural Science Foundation of ChinaProject(KJXM2019028)supported by the Natural Resources Science and Technology Project of Jiangsu Province,ChinaProject(2019B17314)supported by the Fundamental Research Funds for the Central Universities,China。
文摘As a new kind of air-hardening soil reinforcement material,polymer is being widely applied in river-bank slope reinforcement and ecological slope protection area.Thus,more attention should be paid to study the characteristics of reinforced soil after immersion.In this study,water-induced changes in strength characteristics of sand reinforced with polymer and fibers were reported.Several factors,including polymer content(1%,2%,3%and 4%by weight of dry sand),immersion time(6,12,24 and 48 h),dry density(1.40,1.45,1.50,1.55 and 1.60 g/cm^(3),)and fiber content(0.2%,0.4%,0.6%and 0.8%by weight of dry sand)which may influence the strength characteristics of reinforced sand after immersion were analyzed.The microstructure of reinforced sand was analyzed with nuclear magnetic resonance(NMR)and scanning electron microscope(SEM).Experimental results indicate that the compressive strength increases with the increase of polymer content and decreases with the increase of immersion time;the softening coefficients decrease with the increase of the polymer content and immersion time and increase with an increment in density and fiber content.Fiber plays an active role in reducing water-induced loss of strength at 0.6%content.
基金Supported by Science & Engineering Research Council of Singapore (052 118 0052)
文摘In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.
