基于有限生灭过程建立了日历队列的数学模型,提出了一种基于马尔可夫链的动态预测算法(predictresize algorithm based on Markov,PRAM),弥补了上述方法的不足。给出了算法的相关数学分析,并将其实现在J2EE应用服务器OnceAS中。系统实...基于有限生灭过程建立了日历队列的数学模型,提出了一种基于马尔可夫链的动态预测算法(predictresize algorithm based on Markov,PRAM),弥补了上述方法的不足。给出了算法的相关数学分析,并将其实现在J2EE应用服务器OnceAS中。系统实验表明,当事件到达高度密集或到达分布变化剧烈时,该算法可以解决日历队列的性能不稳定问题,使其仍保持出入队时间复杂度O(1)的特性,并且性能更优。展开更多
Watermarking system based on quantization index modulation （QIM） is increasingly popular in high payload applications,but it is inherently fragile against amplitude scaling attacks.In order to resist desynchronizati...Watermarking system based on quantization index modulation （QIM） is increasingly popular in high payload applications,but it is inherently fragile against amplitude scaling attacks.In order to resist desynchronization attacks of QIM digital watermarking,a low density parity check （LDPC） code-aided QIM watermarking algorithm is proposed,and the performance of QIM watermarking system can be improved by incorporating LDPC code with message passing estimation/detection framework.Using the theory of iterative estimation and decoding,the watermark signal is decoded by the proposed algorithm through iterative estimation of amplitude scaling parameters and decoding of watermark.The performance of the proposed algorithm is closer to the dirty paper Shannon limit than that of repetition code aided algorithm when the algorithm is attacked by the additive white Gaussian noise.For constant amplitude scaling attacks,the proposed algorithm can obtain the accurate estimation of amplitude scaling parameters.The simulation result shows that the algorithm can obtain similar performance compared to the algorithm without desynchronization.展开更多
文摘基于有限生灭过程建立了日历队列的数学模型,提出了一种基于马尔可夫链的动态预测算法(predictresize algorithm based on Markov,PRAM),弥补了上述方法的不足。给出了算法的相关数学分析,并将其实现在J2EE应用服务器OnceAS中。系统实验表明,当事件到达高度密集或到达分布变化剧烈时,该算法可以解决日历队列的性能不稳定问题,使其仍保持出入队时间复杂度O(1)的特性,并且性能更优。
基金National Natural Science Foundation of China(No.61272432)Qingdao Science and Technology Development Plan(No.12-1-4-6-(10)-jch)
文摘Watermarking system based on quantization index modulation （QIM） is increasingly popular in high payload applications,but it is inherently fragile against amplitude scaling attacks.In order to resist desynchronization attacks of QIM digital watermarking,a low density parity check （LDPC） code-aided QIM watermarking algorithm is proposed,and the performance of QIM watermarking system can be improved by incorporating LDPC code with message passing estimation/detection framework.Using the theory of iterative estimation and decoding,the watermark signal is decoded by the proposed algorithm through iterative estimation of amplitude scaling parameters and decoding of watermark.The performance of the proposed algorithm is closer to the dirty paper Shannon limit than that of repetition code aided algorithm when the algorithm is attacked by the additive white Gaussian noise.For constant amplitude scaling attacks,the proposed algorithm can obtain the accurate estimation of amplitude scaling parameters.The simulation result shows that the algorithm can obtain similar performance compared to the algorithm without desynchronization.
