A data compression scheme which achieves good compression for practical use

A lossless data compression scheme is investigated with a view to improving the compression ratio for practical use. A new scheme called multidictionary compression is proposed which uses a local dictionary and a global dictionary for removing local and global redundance respectively. An implementation method for this scheme is also provided. Based on the scheme and the implementation method, a compression program called zaa has been implemented. Many experiments with zaa and other compression programs, using several kinds of data, show that the compression ratio of zaa is generally better than those of the other programs