COMPRESSION METHOD OF TIME SERIES DATA AND COMPRESSION DEVICE

PROBLEM TO BE SOLVED: To provide a compression method automatically setting a threshold to be referenced in compressing by thinning numeric data sequence so that a deviation between actual compressibility and target compressibility becomes small.SOLUTION: A compression method thinning data from numeric data sequence on the basis of threshold includes: a first step of initializing the threshold corresponding to target compressibility by use of a predetermined number of numeric data, and relationship between expectation value of compressibility corresponding to specific compression algorithm used for compression and the threshold; a second step of calculating actual compressibility of the predetermined number of numeric data while compressing numeric data by the compression algorithm using the preset threshold; a third step of determining whether it is necessary to reset the threshold or not based on the calculated actual compressibility and the target compressibility; and a fourth step of resetting the threshold corresponding to the target compressibility using the predetermined number of the most recent numeric data and the relationship.