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arXiv 1402.4738cs.ITmath.IT
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数据压缩中新符号压缩增益的一种度量

A measure of compression gain for new symbols in data-compression

Richard M Fredlund

摘要:

霍夫曼编码通常通过使用分组码来改进,例如3-block将是由三个字符的每个可能组合组成的字母表。我们采取的方法是从一个基本的字母表开始,并将其扩展到包括频繁出现的符号集合。我们证明了压缩消息长度的变化,通过引入一个新的聚合符号可以表示为两个熵的差异,仅依赖于引入的符号的概率和长度。该表达式独立于字母表中所有其他符号的概率。对于一个新的符号,这种信息增益的测量可以应用于数据压缩方法中。我们还表明,聚合符号字母表,而不是相互排斥的字母表有可能提供良好的压缩水平,一个简单的实验。最后,本文中定义的压缩增益也可用于特征选择。

英文摘要:

Huffman encoding is often improved by using block codes, for example a 3-block would be an alphabet consisting of each possible combination of three characters. We take the approach of starting with a base alphabet and expanding it to include frequently occurring aggregates of symbols. We prove that the change in compressed message length by the introduction of a new aggregate symbol can be expressed as the difference of two entropies, dependent only on the probabilities and length of the introduced symbol. The expression is independent of the probability of all other symbols in the alphabet. This measure of information gain, for a new symbol, can be applied in data compression methods. We also demonstrate that aggregate symbol alphabets, as opposed to mutually exclusive alphabets have the potential to provide good levels of compression, with a simple experiment. Finally, compression gain as defined in this paper may also be useful for feature selection.

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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