本文關(guān)鍵詞： 無線數(shù)據(jù)廣播 關(guān)鍵字檢索 編碼壓縮　出處：《復(fù)旦大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著移動智能終端設(shè)備的普及、無線通信技術(shù)的發(fā)展,無線數(shù)據(jù)廣播技術(shù)在日常生活的各種應(yīng)用被非常廣泛地應(yīng)用,并受到了工業(yè)界和學(xué)術(shù)界的廣泛關(guān)注。在無線環(huán)境中,廣播是一種高效而且擴(kuò)展性非常強(qiáng)的信息傳輸技術(shù)。服務(wù)器將熱點(diǎn)數(shù)據(jù)通過公共信道周期性地發(fā)送出去,用戶偵聽廣播信道并及時獲取自己感興趣的內(nèi)容。與傳統(tǒng)的點(diǎn)對點(diǎn)數(shù)據(jù)訪問方式相比,采用廣播方式發(fā)送一個數(shù)據(jù)項(xiàng)可以同時滿足需要此數(shù)據(jù)項(xiàng)的所有用戶請求,支持大量的移動計算設(shè)備同時訪問服務(wù)器的數(shù)據(jù)。接受者數(shù)目與發(fā)送代價基本無關(guān),即數(shù)據(jù)廣播能夠支持大量用戶同時并發(fā)訪問數(shù)據(jù)。無線數(shù)據(jù)廣播更適用于用戶數(shù)量巨大的情形,具有可伸縮性強(qiáng)、無線網(wǎng)絡(luò)負(fù)載輕、移動終端節(jié)能性高、用戶隱私零透漏的優(yōu)點(diǎn)。在當(dāng)今移動終端不斷普及的背景下,無線數(shù)據(jù)廣播環(huán)境下的關(guān)鍵字查詢方法研究具有非常大的研究意義和現(xiàn)實(shí)意義。本文提出了在周期數(shù)據(jù)廣播環(huán)境下的一種高效的編碼壓縮的關(guān)鍵字查找索引。關(guān)鍵字檢索技術(shù)在過去已經(jīng)有了大量的研究和發(fā)展,但是在無線環(huán)境的特殊性導(dǎo)致了大部分傳統(tǒng)的方法不能很好地使用于數(shù)據(jù)周期廣播之中。倒排表是全文檢索中廣泛使用的一種索引技術(shù)。倒排表索引和基于哈希的數(shù)據(jù)索引暫時還無法解決索引結(jié)構(gòu)過大的問題。本文提出了一種新型的基于編碼壓縮的關(guān)鍵字查找索引,它對倒排表進(jìn)行編碼壓縮,使用二元組的方式轉(zhuǎn)換倒排表的表示。本文闡述了在索引構(gòu)造的過程中可以通過改變文檔的排序順序來轉(zhuǎn)變二元組的表示結(jié)果,而獲取文檔的最優(yōu)排列順序使得索引大小最小的問題被證實(shí)了是NP問題。此外,結(jié)合索引構(gòu)造的過程,本文提出了純文本文檔數(shù)據(jù)廣播的一種調(diào)度算法。本文對比提出的算法和已有的多種算法在真實(shí)數(shù)據(jù)下進(jìn)行模擬實(shí)驗(yàn),從實(shí)驗(yàn)結(jié)果可以看出,經(jīng)過編碼壓縮后索引大小有了大幅下降,驗(yàn)證了該索引結(jié)構(gòu)在訪問時間和調(diào)諧時間方面的高效特性。
[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.
【學(xué)位授予單位】：復(fù)旦大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN934;TP391.3

【參考文獻(xiàn)】

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本文編號：1535478