k-匿名机制是LBS(location based service)中保证查询隐私性的重要手段.已有文献指出,现有的k-匿名机制不能有效保护连续性查询的隐私性.提出一种连续查询发送模型,该模型融合了查询发送时间的间隔模型和连续性模型,针对此模型下的两种k...k-匿名机制是LBS(location based service)中保证查询隐私性的重要手段.已有文献指出,现有的k-匿名机制不能有效保护连续性查询的隐私性.提出一种连续查询发送模型,该模型融合了查询发送时间的间隔模型和连续性模型,针对此模型下的两种k-匿名算法Clique Cloaking和Non-clique Cloaking,分别提出了一种连续查询攻击算法.在此攻击算法下,匿名集的势不再适合作为查询匿名性的度量,因此提出一种基于熵理论的度量方式AD(anonymityd egree).实验结果表明,对连续性很强的查询,攻击算法重识别用户身份的成功率极高;AD比匿名集的势更能反映查询的匿名性.展开更多
A bursty traffic model is introduced in this paper to describe the statistical characteristics of packet video. The performance of leady bucket algorithm with bursty traffic input is analyzed. The influences of variou...A bursty traffic model is introduced in this paper to describe the statistical characteristics of packet video. The performance of leady bucket algorithm with bursty traffic input is analyzed. The influences of various parameters on QOS (Quality of Service) are investigated. The analysis shows that although the loss probability decreases through expanding the buffer capacity, the delay and delay jitter increase, whose effect on QOS will not be negligible.展开更多
联机连续文本识别是字符识别技术领域中新的研究方向.基于分层构筑法(Level-Building,LB)和动态时间规整算法(Dynamic Time Warping,DTW)建立了面向连续手写文本识别的手写部件识别器.将部件看作笔段和连续文本的中间模式,根据手写文本...联机连续文本识别是字符识别技术领域中新的研究方向.基于分层构筑法(Level-Building,LB)和动态时间规整算法(Dynamic Time Warping,DTW)建立了面向连续手写文本识别的手写部件识别器.将部件看作笔段和连续文本的中间模式,根据手写文本的特点建立了由484个手写部件构成的部件集.提取笔段的长度、角度等特征用于LB中每一层的DTW网格匹配中.测试样本包括6 763个汉字和303个连续手写文本.实验结果表明手写体部件集能够有效地支撑笔段和连续文本之间的联系,串识别率达到86.47%.展开更多
基金Supported by Foundation of Electronic Science Institutethe National Natural Science Foundation of China
文摘A bursty traffic model is introduced in this paper to describe the statistical characteristics of packet video. The performance of leady bucket algorithm with bursty traffic input is analyzed. The influences of various parameters on QOS (Quality of Service) are investigated. The analysis shows that although the loss probability decreases through expanding the buffer capacity, the delay and delay jitter increase, whose effect on QOS will not be negligible.
文摘联机连续文本识别是字符识别技术领域中新的研究方向.基于分层构筑法(Level-Building,LB)和动态时间规整算法(Dynamic Time Warping,DTW)建立了面向连续手写文本识别的手写部件识别器.将部件看作笔段和连续文本的中间模式,根据手写文本的特点建立了由484个手写部件构成的部件集.提取笔段的长度、角度等特征用于LB中每一层的DTW网格匹配中.测试样本包括6 763个汉字和303个连续手写文本.实验结果表明手写体部件集能够有效地支撑笔段和连续文本之间的联系,串识别率达到86.47%.
