Answering Multiple Queries in Compressed Texts

With the exponential increment of data, compression technology becomes an important tool in the field of data management, especially in text management. An increasing pressing challenge is how to efficiently query these massive amounts of sequence data in their compressed format. In this paper we study the problem of answering subsequence-search queries on LZ78 format of texts. We propose the concept of conditional common sub strings of queries to improve query performance. We present a techniques to find minimal conditional common sub strings in compressed text and a local uncompressing technique to verify and locate positions of answers in text. Finally, the experimental results over real data demonstrate the efficiency of our algorithm.