为解决软件定义网络(software defined network,SDN)控制器易受分布式拒绝服务(distributed denial of service,DDoS)攻击的问题,提出了一种基于Sibson距离的DDoS攻击检测方法。首先,针对现有SDN控制器负载过重问题,设计了一种分层式DDo...为解决软件定义网络(software defined network,SDN)控制器易受分布式拒绝服务(distributed denial of service,DDoS)攻击的问题,提出了一种基于Sibson距离的DDoS攻击检测方法。首先,针对现有SDN控制器负载过重问题,设计了一种分层式DDoS攻击检测架构,通过采用多个代理控制器来减轻主控制器负荷;其次,针对现有DDoS攻击检测误报率高的问题,提出了一种基于Sibson距离DDoS攻击检测算法,在提高检测时效性和保证检测精度的同时,加强对正常突发流的识别能力。仿真实验表明,该方法能有效区分攻击流和正常突发流,提高了网络的稳健性。展开更多
C^1 natural element method （C^1 NEM） is applied to strain gradient linear elasticity, and size effects on mi crostructures are analyzed. The shape functions in C^1 NEM are built upon the natural neighbor interpolati...C^1 natural element method （C^1 NEM） is applied to strain gradient linear elasticity, and size effects on mi crostructures are analyzed. The shape functions in C^1 NEM are built upon the natural neighbor interpolation （NNI）, with interpolation realized to nodal function and nodal gradient values, so that the essential boundary conditions （EBCs） can be imposed directly in a Galerkin scheme for partial differential equations （PDEs）. In the present paper, C^1 NEM for strain gradient linear elasticity is constructed, and sev- eral typical examples which have analytical solutions are presented to illustrate the effectiveness of the constructed method. In its application to microstructures, the size effects of bending stiffness and stress concentration factor （SCF） are studied for microspeciem and microgripper, respectively. It is observed that the size effects become rather strong when the width of spring for microgripper, the radius of circular perforation and the long axis of elliptical perforation for microspeciem come close to the material characteristic length scales. For the U-shaped notch, the size effects decline obviously with increasing notch radius, and decline mildly with increasing length of notch.展开更多
文摘为解决软件定义网络(software defined network,SDN)控制器易受分布式拒绝服务(distributed denial of service,DDoS)攻击的问题,提出了一种基于Sibson距离的DDoS攻击检测方法。首先,针对现有SDN控制器负载过重问题,设计了一种分层式DDoS攻击检测架构,通过采用多个代理控制器来减轻主控制器负荷;其次,针对现有DDoS攻击检测误报率高的问题,提出了一种基于Sibson距离DDoS攻击检测算法,在提高检测时效性和保证检测精度的同时,加强对正常突发流的识别能力。仿真实验表明,该方法能有效区分攻击流和正常突发流,提高了网络的稳健性。
基金supported by the SDUST Spring Bud (2009AZZ021)Taian Science and Technology Development (20112001)
文摘C^1 natural element method （C^1 NEM） is applied to strain gradient linear elasticity, and size effects on mi crostructures are analyzed. The shape functions in C^1 NEM are built upon the natural neighbor interpolation （NNI）, with interpolation realized to nodal function and nodal gradient values, so that the essential boundary conditions （EBCs） can be imposed directly in a Galerkin scheme for partial differential equations （PDEs）. In the present paper, C^1 NEM for strain gradient linear elasticity is constructed, and sev- eral typical examples which have analytical solutions are presented to illustrate the effectiveness of the constructed method. In its application to microstructures, the size effects of bending stiffness and stress concentration factor （SCF） are studied for microspeciem and microgripper, respectively. It is observed that the size effects become rather strong when the width of spring for microgripper, the radius of circular perforation and the long axis of elliptical perforation for microspeciem come close to the material characteristic length scales. For the U-shaped notch, the size effects decline obviously with increasing notch radius, and decline mildly with increasing length of notch.
