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arXiv cs/0612019cs.ITmath.IT
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关于有限存储器通用数据压缩及单个序列的分类

On Finite Memory Universal Data Compression and Classification of Individual Sequences

Jacob Ziv

摘要:

考虑这样一种情况,其中有限字母表上的半无限个体序列X的N个字母的连续块通过某种一对一映射被压缩成二进制序列。在编码器中没有关于X的先验信息,因此必须采用通用的数据压缩算法。众所周知,如果通用的LZ 77数据压缩算法被连续地应用于N个块,则对于特定的单个序列X实现了最佳的无差错压缩,因为$N$趋于无穷大。本文讨论了有限N块的通用数据压缩算法所能达到的最佳压缩效果。接下来,考虑一种称为分类器(或称分类器)的设备,它观察一个单独的训练序列X。分类器的任务是检查长度为N的各个测试序列,并根据一些适当的准则来决定测试N序列是否具有与训练序列X捕获的特征相同的特征,或者是否充分不同。这里再次证明,具有在N中为线性的存储空间复杂度的特定通用上下文分类器本质上是最优的。这可能有助于在学习理论和计算生物学中的概率后缀树(PST)方法的理论“个体序列”的理由。

英文摘要:

Consider the case where consecutive blocks of N letters of a semi-infinite individual sequence X over a finite-alphabet are being compressed into binary sequences by some one-to-one mapping. No a-priori information about X is available at the encoder, which must therefore adopt a universal data-compression algorithm. It is known that if the universal LZ77 data compression algorithm is successively applied to N-blocks then the best error-free compression for the particular individual sequence X is achieved, as $N$ tends to infinity. The best possible compression that may be achieved by any universal data compression algorithm for finite N-blocks is discussed. It is demonstrated that context tree coding essentially achieves it. Next, consider a device called classifier (or discriminator) that observes an individual training sequence X. The classifier's task is to examine individual test sequences of length N and decide whether the test N-sequence has the same features as those that are captured by the training sequence X, or is sufficiently different, according to some appropriatecriterion. Here again, it is demonstrated that a particular universal context classifier with a storage-space complexity that is linear in N, is essentially optimal. This may contribute a theoretical "individual sequence" justification for the Probabilistic Suffix Tree (PST) approach in learning theory and in computational biology.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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