两种联邦滤波系统级故障检测方案对比与仿真

从联邦滤波的故障检测特点出发,以SINS/GPS/ADS/TACAN/RADAR组合导航系统为对象,对基于量测一致性和残差χ2检测的两级故障检测法、双状态递推故障检测法两种系统级故障检测方案进行了较为详细的分析比较,并通过预设故障模型进行了仿真.仿真结果表明:故障检测部分的加入可有效地提高多传感器组合导航系统的容错性和可靠性.两种检测方案对软、硬故障都有较高的灵敏度,但都不同程度出现误警和漏检情况,总体而言,基于量测一致性和残差χ2检测的检测方案更有优势.     

基于虚拟散列安全访问路径VHSAP的云计算路由平台防御DDoS攻击方法

防御分布式拒绝服务DDoS（distributed denial of service）攻击是云计算平台安全保护中的一个关键问题。在研究大规模网络防御DDoS攻击的安全覆盖服务SOS（security overlay service）方法的基础上,揭示了SOS在节点被攻击时的退出机制存在的安全漏洞,根据云计算路由策略改进了一致性散列算法Chord,提出了适用于云计算路由平台三层架构的虚拟散列安全访问路径VHSAP（virtualization hash security access path）,在安全访问路径中引入了心跳机制,利用虚拟机技术实现弹性的虚拟节点,完成在云平台中被攻击节点之间的无缝切换,保证用户对云计算平台的安全访问。针对VHSAP防御DDoS的性能进行了仿真实验,重点研究了在散列安全访问路径HSAP中被攻击节点数和切换时延等参数,并将实验结果与SOS方法进行了比较。实验结果表明在DDoS攻击下,VHSAP具有较高的数据通过率,可以提高云计算平台的安全性。     

改进的FAHP信息安全风险评估方法

结合当前信息安全风险评估的特点和发展现状,将模糊数学的相关优选理论、模糊一致矩阵、变权法、二次评判有机结合,提出了一种基于FAHP的信息安全风险评估模型的改进方案。首先,模糊一致矩阵的引入,保证了判断矩阵的一致性。其次,将变权法引入到权重向量的计算过程中,促使综合指标增大,使评估因素的权重能更好地体现相应因素在决策中的作用。最后,通过引入二次评判,提高了风险评估的准确性。通过实例分析,证明了该方法可以有效的应用到信息系统安全风险评估中去,实验结果符合实际。     

基于角色的网格授权策略的一致集成服务

提出一种动态捕获和集成本地变更的授权策略的服务框架,保障共享资源持续可用。并给出一组调解算法,可把对VO授权系统调整的影响降低到最小。     

基于麦克风阵列的相容时延矢量声源定位方法

时延估计是常用的声源定位方法,传统的算法将定位分为两个步骤,即先估计麦克风阵列中每一对基元的接收信号时延,然后根据这些时延用几何的方法确定声源的位置。在低信噪比下,一对麦克风的时延估计误差较大,导致定位误差较大。相容时延矢量估计算法将两步合为一步,没有逐对估计时延,而是构造一个目标函数,通过搜索得到声源的位置。仿真结果表明,在低信噪比下,只需要较短的数据,该算法仍可得到较高的定位精度。     

Improving Control In Water Management. Meeting conditions for control with the ISI-approach

Water management steers a middle course between control and chaos. The concept of control in water management is the topic of this paper. Conditions for control in water management are: aconsistent policy, gaining support and an adequate informationsupply. It is demonstrated that the balance between these three conditions of control depends on the type of water managementconsidered. In this paper four different types of water management are distinguished based on the conditions for control.The concept presented in this paper is validated on basis of three case studies. The paper concludes with a presentation of an approach which is interactive and aims at an integral and sustainable development.     

AUTOREGRESSIVE PROCESSES WITH A TIME DEPENDENT VARIANCE

Abstract. We study nonstationary autoregressive time series where the variance of the residual process is allowed to depend on time. In earlier publications the variance has been modelled by a step function. We look at more general classes of functions and propose two estimates of the autoregressive coefficients, both of which are consistent under weak assumptions. We also show how it is possible to obtain an estimate in practice using an iterative regression procedure.     

前后处理软件与Procast接口方式的研究

讨论了3种前后处理软件与Procast的接口方式,解决了复杂铸件模型经过网格划分后,导入Procast时出现铸件、铸型等界面不一致(NCONIC)现象.     

Determining a radio signal consistent reception zone within cell boundaries under urban conditions

The cell part of a cellular mobile communication system is determined where the radio signal level exceeds the reception threshold value with allowance for multibeam radiowave propagation (with the Rayleigh fading distribution).