Patent ID: 7424391

Claim:
A period division statistics device that is connected to storage and an input device to take statistics based on a value of an event occurred at a certain time point and statistical target information indicating the occurrence time thereof, said period division statistics device comprising: referring a statistical calculation rule that defines a starting point of a statistical target period, an interval of a starting point of each unit time period and a time length of each unit time period in order to divide the statistical target period into a plurality of unit time periods; storing statistical target information into storage, when the information is inputted through said input device, reading, when any of the unit time periods expires, all pieces of the statistical target information whose occurrence times are contained in the expired unit time period from said storage, said unit time period being specified by the interval of starting point and the time length that are defined in said statistical calculation rule; executing predetermined statistical calculations for the values of events indicated by the read statistical target information; storing a statistical result obtained by the statistical calculations into said storage; selecting the unit time period that contains the occurrence time of the event indicated by the inputted statistical target information among the unit time periods whose statistical results are registered in said storage, when the statistical target information is inputted through said input device; reading all pieces of the statistical target information whose occurrence times are contained in the selected unit time period from said storage for each of the selected unit time periods; re-executing the statistical calculation for the values of events indicated by the read statistical target information; and overwriting the statistical result onto said storage.