无线数据广播环境下的关键字检索方法研究

发布时间：2018-02-25 22:39

本文关键词： 无线数据广播关键字检索编码压缩　出处：《复旦大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着移动智能终端设备的普及、无线通信技术的发展,无线数据广播技术在日常生活的各种应用被非常广泛地应用,并受到了工业界和学术界的广泛关注。在无线环境中,广播是一种高效而且扩展性非常强的信息传输技术。服务器将热点数据通过公共信道周期性地发送出去,用户侦听广播信道并及时获取自己感兴趣的内容。与传统的点对点数据访问方式相比,采用广播方式发送一个数据项可以同时满足需要此数据项的所有用户请求,支持大量的移动计算设备同时访问服务器的数据。接受者数目与发送代价基本无关,即数据广播能够支持大量用户同时并发访问数据。无线数据广播更适用于用户数量巨大的情形,具有可伸缩性强、无线网络负载轻、移动终端节能性高、用户隐私零透漏的优点。在当今移动终端不断普及的背景下,无线数据广播环境下的关键字查询方法研究具有非常大的研究意义和现实意义。本文提出了在周期数据广播环境下的一种高效的编码压缩的关键字查找索引。关键字检索技术在过去已经有了大量的研究和发展,但是在无线环境的特殊性导致了大部分传统的方法不能很好地使用于数据周期广播之中。倒排表是全文检索中广泛使用的一种索引技术。倒排表索引和基于哈希的数据索引暂时还无法解决索引结构过大的问题。本文提出了一种新型的基于编码压缩的关键字查找索引,它对倒排表进行编码压缩,使用二元组的方式转换倒排表的表示。本文阐述了在索引构造的过程中可以通过改变文档的排序顺序来转变二元组的表示结果,而获取文档的最优排列顺序使得索引大小最小的问题被证实了是NP问题。此外,结合索引构造的过程,本文提出了纯文本文档数据广播的一种调度算法。本文对比提出的算法和已有的多种算法在真实数据下进行模拟实验,从实验结果可以看出,经过编码压缩后索引大小有了大幅下降,验证了该索引结构在访问时间和调谐时间方面的高效特性。
[Abstract]:With the popularity of mobile intelligent terminal devices and the development of wireless communication technology, wireless data broadcasting technology has been widely used in daily life, and has been widely concerned by industry and academia. Broadcast is an efficient and highly scalable information transmission technology. The server periodically transmits hot data through the common channel. The user listens to the broadcast channel and gets the content of his interest in time. Compared with the traditional point-to-point data access mode, the broadcast mode can send a single data item to satisfy all the user requests that need the data item at the same time. Supports a large number of mobile computing devices accessing the server's data at the same time. That is, data broadcast can support a large number of users to access data simultaneously. Wireless data broadcast is more suitable for the situation of large number of users, with strong scalability, light wireless network load, high energy saving of mobile terminal. The advantage of zero disclosure of user privacy. Under the background of the increasing popularity of mobile terminals today, The research of keyword query method in wireless data broadcasting environment is of great significance and practical significance. In this paper, an efficient coded compressed keyword lookup index in periodic data broadcast environment is proposed. Key word retrieval technology has been a lot of research and development in the past. However, due to the particularity of wireless environment, most of the traditional methods can not be used in data cycle broadcast very well. Inverted Table is a widely used indexing technology in full-text retrieval. This paper presents a new keyword lookup index based on coding compression. It encodes and compresses the inverted table and converts the representation of the inverted table by using binary groups. This paper expounds that in the process of index construction, the result of binary group representation can be changed by changing the sort order of documents. The problem of obtaining documents in the optimal order in which the index size is minimal has been proved to be a NP problem. In addition, in combination with the process of index construction, In this paper, a scheduling algorithm for pure text document data broadcasting is proposed. The index size is greatly reduced after coding and compression, which verifies the efficiency of the index structure in terms of access time and tuning time.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN934;TP391.3

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