针对 Chord 结构并未考虑用户查询偏好的问题，提出了一种基于语义网络的分层 DHT 以解决该问题。在该分层 DHT中，节点和关键词按语义关系组织，节点选择自己感兴趣的区域加入，每个区域选一个稳定节点作为超级节点，节点间按语义关系组织，各个区域按2-Chord 结构组织。在此基础上提出了相应的路由算法，该算法先检查关键词是否归本地区域管理，否则转发给上层超级节点去处理，如此递归转发查询直至返回查询结果。实验发现，用户的查询关键词较偏好本地区域时，分层 DHT 较2-Chord 的路由效率得到了一定提升，这种效果随着偏好度的增大越加明显。%Aiming at Chord structure and considering the preferential problems of user query,a hierarchy DHT based on semantic network is proposed to resolve the issue.In this hierarchical DHT,nodes and keywords are organized according to semantic relations,nodes select the areas that are interesting to join in,a stable node of each area is selected as a super node,the organizations are done between nodes according to semantic relationships,and each area is organized according to 2-Chord structure.On this basis,the corresponding routing algorithm is put forward,first,this algorithm checks if keywords belong to this region management,otherwise forward to the upper super-peer to deal with,do this recursive forwarding check,until returning to query results.It was found that,when a user's query keywords prefer local zone, the routing efficiency of hierarchical DHT has some improvement compared with 2-Chord,this effect becomes increasingly obvious with in-creasing preference.
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