Patent ID: 8521910

Claim:
A data collection system comprising a plurality of data compressing devices for compressing data, a plurality of data relaying devices for relaying the data, and a data collecting device for collecting the data, said plurality of said data relaying devices being arranged hierarchy by hierarchy responding to the number of hops or a round trip time up to the data collecting device so that the smaller the number of the hops or the round trip time of the data relaying device up to the data collecting device is, the higher the hierarchy of the data relaying device becomes, said data collecting device receiving already compressed data containing a data analysis result, being an analysis result of a statistical special feature of the data that is a target of compression, a code that is decided for a symbol, being a before-compression bit string, responding to the analysis result, and data conversion information indicative of a correspondence between the symbol and the code from each relaying device of a highest-place hierarchy, wherein the data collecting device comprises: a basic symbol description format recording means for storing symbol description information in which a basic symbol, being a symbol divided into a minimum unit, and a description format in which the basic symbol has been expressed with other formats have been caused to correspond to each other; a derivative symbol format recording means for storing information in which a derivative symbol, being a symbol in which the basic symbols have been combined, and an aggregation of the basic symbols constituting the derivative symbol have been caused to correspond to each other; a code operating means for deriving a frequency of the symbol for each symbol corresponding to the code being contained in the already compressed data based upon the data analysis result being contained in the received already compressed data; and a code operation developing means for adding the frequency of the description format, out of the frequencies obtained by the code operating means, to the frequency of the basic symbol corresponding to the above description format, and adding the frequency of the derivative symbol to the frequency of each basic symbol constituting the derivative symbol.