DATA PRESENCE/ABSENCE DETERMINATION DEVICE, DATA PRESENCE/ABSENCE DETERMINATION METHOD AND DATA PRESENCE/ABSENCE DETERMINATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a technology for determining whether or not input data are new data which are not included in a certain data set such that a storage capacity to be used is smaller than the case of using a CBF(Counting Bloom Filter), and that data are erasable from the data set.SOLUTION: A filter 28 which is equivalent to making common the high-order bits of a counting bloom filter (CBF) is used. Then, the presence/absence of data is determined on the basis of the value of a low-order bit, and when the low-order bit corresponding to the hash value of additional data is "1", the value of the high-order bit is set to "1".