【摘要】 在移动计算环境下,无线数据广播是一种可拓展性强、节能、适合用户数量大的信息发布技术.提出了一个在无线数据广播环境下支持空间关键字检索的框架,并提出了一种基于网格索引与倒排表结合的空中索引:IRGI(information retrieval grid index).IRGI的优点是:1)相对文档的大小,索引本身很小,因此可以在一个周期内分布多次索引,以降低访问延迟,增强用户体验效果;2)通过网格索引和倒排表,用户可以剪枝落在区域外的或者不包含感兴趣关键字的文档,从而使用户保持监听状态的时间大大减小,降低能量消耗.最后通过人工生成的数据和真实地图的数据进行了实验模拟,实验结果证明了该方法不但访问延迟低,而且能量消耗小.更多还原

【Abstract】 Wireless data broadcast is a scalable and energy-efficient technology of information disseminating,which allows simultaneous access by an arbitrary number of clients in mobile environment.This paper proposes a framework which supports spatial keyword queries via wireless broadcast.Based on the proposed framework,this paper proposes an air index,namely IRGI(Information Retrieval Grid Index),which is based on grid index and inverted file.The main advantages of IRGI are:(1)the index size is relatively small so that it can be duplicated several times during one broadcast cycle to shorten the access latency;(2)with the grid index and the inverted files, clients are able to prune the documents outside the query region or the documents that contain no interested keywords;so the energy consumption by clients is reduced.The performance of IRGI is evaluated with both synthetic and real data sets.Experimental results show that the proposed IRGI is access-latency-friendly and energy-efficient.更多还原