...The following classes are provided : POSIXcti, POSIXctp,
TimeIntervalDataFrame, TimeInstantDataFrame, SubtimeDataFrame ;
methods to switch from a class to another and to modify the time support
of series (hourly time series to daily time series for instance) are also
defined.
Tools provided can be used for instance to handle environmental monitoring
data (not always produced on a regular time base).