We first design a discrete hyperchaotic system via piece-wise linear state feedback. The states of the closed loop system are locally expanding in two directions but absolutely bounded on the whole, which implies hype...We first design a discrete hyperchaotic system via piece-wise linear state feedback. The states of the closed loop system are locally expanding in two directions but absolutely bounded on the whole, which implies hyperchaos. Then, we use three suchlike hyperchaotic systems with different feedback gain matrices to design a pseudo-random sequence generator (PRSG). Through a threshold function, three sub-sequences generated from the output of piecewise linear functions are changed into 0-1 sequences. Then, followed by XOR operation, an unpredictable pseudo-random sequence (PRS) is ultimately obtained. The analysis and simulation results indicate that the PRS, generated with hyperchaotic systems, has desirable statistical features.展开更多
用图书的出版信息和用户生成的社会信息从社会媒体中搜索出相关的图书已成为信息检索系统的一个研究热点。大部分的信息检索系统都是由单一的检索方法构成,随着用户需求的不断增加,这些系统难以满足用户需求。针对上述问题,提出了一种...用图书的出版信息和用户生成的社会信息从社会媒体中搜索出相关的图书已成为信息检索系统的一个研究热点。大部分的信息检索系统都是由单一的检索方法构成,随着用户需求的不断增加,这些系统难以满足用户需求。针对上述问题,提出了一种基于重排序融合的图书检索系统。使用伪相关反馈技术对用户查询内容进行扩展,并将检索结果作为初排序结果;再使用用户生成的社会信息特征对初排序结果进行重排序,最后采用排序学习模型对多种重排序策略得到的结果进行融合。在INEX 2012—2014 Social Book Search公开数据集上针对其他先进检索系统进行了对比实验,实验结果表明,系统的性能(NDCG@10)优于其他方法构成的图书检索系统。展开更多
基金This project was supported by the National Natural Science Foundation of China (69874025).
文摘We first design a discrete hyperchaotic system via piece-wise linear state feedback. The states of the closed loop system are locally expanding in two directions but absolutely bounded on the whole, which implies hyperchaos. Then, we use three suchlike hyperchaotic systems with different feedback gain matrices to design a pseudo-random sequence generator (PRSG). Through a threshold function, three sub-sequences generated from the output of piecewise linear functions are changed into 0-1 sequences. Then, followed by XOR operation, an unpredictable pseudo-random sequence (PRS) is ultimately obtained. The analysis and simulation results indicate that the PRS, generated with hyperchaotic systems, has desirable statistical features.
文摘用图书的出版信息和用户生成的社会信息从社会媒体中搜索出相关的图书已成为信息检索系统的一个研究热点。大部分的信息检索系统都是由单一的检索方法构成,随着用户需求的不断增加,这些系统难以满足用户需求。针对上述问题,提出了一种基于重排序融合的图书检索系统。使用伪相关反馈技术对用户查询内容进行扩展,并将检索结果作为初排序结果;再使用用户生成的社会信息特征对初排序结果进行重排序,最后采用排序学习模型对多种重排序策略得到的结果进行融合。在INEX 2012—2014 Social Book Search公开数据集上针对其他先进检索系统进行了对比实验,实验结果表明,系统的性能(NDCG@10)优于其他方法构成的图书检索系统。
