中央加密系统在动态密钥分存方案中的应用研究*

在单齿加密－解密算法基础上,提出了一种基于单齿中央加密系统的动态密钥分存方案。研究指出：任意K个系统成员B={B1,B2,…,Bk},它们各自选择无规则分布的正整数集合XBi={xi1,xi2,…,xim}。其中i=1,2,…,k,并公开XBi。利用P〈G, X,X′〉,任意l个(或更多)Bi能够重构共享密钥。其中k,l∈N,l≤k。研究结果表明,该方案具有良好的保密性和安全性。     

高效节能的能量异构传感器网络数据聚合协议

介绍了一种有效地用于能量异构传感网络的数据采集协议EDGA。EDGA在能量最小化的网内通信和均衡能量负荷等性能上有很好的表现。它通过基于权重选择概率选取的簇头获得了更好的处理能量异构环境的能力,并且利用一种简单但有效的方法解决了簇内的面积覆盖问题。仿真结果表明,该EDGA方法在能量异构无线传感网络的数据采集应用中比LEACH和HEED等方法有明显的优势。     

改进型Boussinesq方程高精度紧致差分显格式

采用一种高精度的紧致差分显格式对改进型Boussinesq方程进行数值求解;采用具有TVD性质的三阶Runge-Kutta方法进行预报,用三次样条函数进行校正,时间精度可达到四阶;在空间离散上采用六阶精度的三点紧致显格式进行计算;运用以上数值格式对Beji和Nadaoka改进型Boussinesq方程进行了求解,求解证明:高精度的数值结果和已知的试验结果吻合良好.作为验证算例,同时对波浪在台阶上的传播进行了模拟,从效果对比上可以看出,所得结果明显比Kittitanasuan的计算结果更靠近试验值.     

A sink moving scheme based on local residual energy of nodes in wireless sensor networks

In the application of periodic data-gathering in sensor networks, sensor nodes located near the sink have to forward the data received from all other nodes to the sink, which depletes their energy very quickly. A moving scheme for the sink based on local residual energy was proposed. In the scheme, the sink periodically moves to a new location with the highest stay-value defined by the average residual energy and the number of neighbors. The scheme can balance energy consumption and prevent nodes around sink from draining their energy very quickly in the networks. The simulation results show that the scheme can prolong the network lifetime by 26%–65% compared with the earlier schemes where the sink is static or moves randomly. Foundation item: Project(60673164) supported by the National Natural Science Foundation of China; Project(20060533057) supported by the Specialized Research Foundation for the Doctoral Program of Higher Education of China     

对一种多重密钥共享认证改进方案的完善

通过分析一种多重密钥共享认证改进方案,指出其中存在的漏洞和防止成员欺骗中存在的问题,提出了自己的完善方案,使其在共享多个密钥、子密钥可以重复使用、防止管理者欺骗及参与成员欺骗等方面更加完善．     

测绘工程专业课程体系改革探讨

通过对测绘工程传统人才培养方案的分析,搭建了通识教育、学科教育、专业知识、专业方向及集中实践教学主要平台,该模式充分考虑了学生的个性发展方向,强化了对学生实际动手能力的培养,并按照提高综合素质的要求,拓宽了学生的知识面,满足了培养学生宽厚的知识基础、扎实的专业知识和较强的实践动手能力的要求．     

一种新的多重代理多重数字签名方案*

基于离散对数问题,提出了一种新的多重代理多重签名方案,该方案指定了签名验证人,在门方案的基础上又完善了签名过程,最终签名由其中一位代理人给出,从而避免了门方案中不具有追踪性、可滥用签名权的漏洞,签名体现了签名者身份信息,进一步防止了伪造攻击,是一种相对安全的多种代理多重数字签名方案。     

一种基于无线传感器网络的目标跟踪调度算法*

基于无线传感器网络的IPv4/IPv6混合组网的视频监控系统的调度算法可以有效地增强视频监控的智能控制功能。在综合考虑无线传感器网络的自身特性和监控系统功能扩展清晰度要求的基础上,对原有的后来先服务调度(LCFS)算法进行改进,并设计和实现了一种简单有效的目标检测和跟踪方案,提出了清晰度最优负载平衡的调度算法(DOLB)。理论分析及实验结果表明,该算法性能明显优于原有的调度算法。     

针对影像处理的快速二维离散余弦转换算法

由于离散余弦转换在影像处理领域之重要性与日俱增,且消耗许多处理器运算时间,所以众多快速二维离散余弦转换算法不断被发表。该文提出一个应用于JPEG及MPEG图像处理的快速二维8×8离散余弦转换算法,该算法主要运用基本的累加及移位运算,快速评估8×8影像区块的复杂程度,可调整离散余弦转换参数的计算数量。该算法只需花费少量硬件成本,如比较器、加法器、移位器,便可有效降低离散余弦转换运算时间,且在模拟结果显示所提出的算法与传统及整数离散余弦转换相比,可达到较快的运算速度,且在量化系数较大的情况下,可得到更好效果。     

Viscous liquid sloshing damping in cylindrical container using a volume of fluid method

Liquid sloshing is a kind of very complicated free surface flow and exists widely in many fields. In order to calculate liquid sloshing damping precisely a volume of fluid method based on finite volume scheme is used to simulate free surface flows in partly filled cylindrical containers. A numerical method is presented to simulate the movement of the free surface flow, in which a piecewise linear interface construction scheme and an unsplit Lagrangian advection scheme instead of Eulerian advection scheme are used. The damping performance of liquid sloshing in cylindrical containers under fundamental sloshing mode is investigated. There are four factors determining the surface-wave damping: free surface, boundary-layer, interior fluid and contact line. In order to study different contributions from these four factors to whole damping, several examples are simulated. No-slip and slip wall boundary conditions on both side wall and bottom wall of the cylindrical containers are studied to compare with the published results obtained by solving Stokes equations. In the present method the first three main factors can be considered. The simulation results show that the boundary-layer damping contribution increases while the interior fluid damping contribution decreases with increase of Reynolds number. Supported by the National Natural Science Foundation of China (Grant No. 10532010)