围绕如何在浩瀚的中文网页中找到用户感兴趣的内容,提出了基于UCL(Uniform Content Locator)的“二阶过滤法”.它将媒体空间中的信息用UCL语义格(Semantic Cases based on UCL,SCU)表示,通过语义向量空间模型(Semantic Vector Space Model,SVSM)对网页的语义矩阵进行分析计算,粗略筛选出用户感兴趣的网页;再借助精细语义逐句解读其内容,提取用户所关注的信息.根据用户的阅读行为动态了解用户的兴趣变化,建立用户兴趣的本体模型,并分析和定义了用户兴趣度的度量.实验验证了上述过滤方法的有效性,其测试结果同向量空间模型(Vector SpaceModel,VSM)进行了比较,性能明显优于VSM.
As to the safety threats faced by sensor networks (SN),nodes limitations of computation,memory and communication,a secure location algorithm (node cooperative secure localization,NCSL) is presented in this paper. The algorithm takes the im-provements of SN location information security as its design tar-gets,utilizing nodes' cooperation to build virtual antennae array to communicate and localize,and gains arraying antenna advantage for SN without extra hardware cost,such as reducing multi-path effects,increasing receivers' signal to noise ratio and system capa-bility,reducing transmitting power,and so on. Simulations show that the algorithm based on virtual antennae array has good local-ization ability with a at high accuracy in direction-of-arrival (DOA) estimation,and makes SN capable to resist common malicious attacks,especially wormhole attack,by using the judgment rules for malicious attacks.
