Zheng Xiangwei

A teaching evaluation model based on information entropy and its application

Most universities and colleges are employing teaching evaluations to guide their work. However, no feasible and effective systems satisfy their requirements currently. This paper first presents a suit of evaluation indices based on the multiple evaluation subjects and developmental evaluation theory. Then, a teaching evaluation model based on information entropy is proposed, in which weight calculation of evaluation indices doesnpsilat require past experiences and is easily implemented by computers. At last, the information entropy based teaching evaluation system (IETES) is described, which adopts B/S architecture and is deployed on the Internet. The applications in our school show that the IETES is feasible and effective.

Secure connectivity analysis of mobile Ad Hoc social networks

移动Ad Hoc 社交网络(MASNs) 的安全性是近几年来的研究热点问题. 在MASNs 中, 安全通信需要将链接建立在相互信任的基础上, 因此具有很大的挑战性. 本文主要对MASNs 安全连通性的相关特征进行分析. 首先, 通过将节点间的信任关系的分布描述成一种更新随机过程. 在此基础上,可以通过四个步骤构造安全图: 构造几何图、构造信任图、构造安全图、安全图的增广. 然后, 利用连续渗流理论证明了安全MASNs 中渗流现象的存在. 最后, 分析了安全连通性中的关键密度特征这一核心问题. 通过聚类系数法获取了关键密度 cs 的更为严格的下界. 仿真结果表明, 节点密度以及信任关系都会对MASNs 的安全连通性产生极大影响. 该结论能够为MASNs 的安全连通性研究提供基础性的指导.