LSC Detector Characterization Working Group
Subgroup on Reduced Data Sets

Leader: Jim Brau

There are two obvious ways to reduce data sets to more manageable volumes: eliminating extraneous channels (extraneous to a given purpose) and decimating the retained channels. Complicating this task are differing needs of various experimenters. For example, a person wishing to study the correlation of a seismometer's reading with the interferometer's differential mode readout channel may want a customized data set for some period of time that contains only those two channels, with the interferometer channel decimated to match the seismometer's sampling rate. Another experimenter may wish to look only at correlations between wave-front-sensor signals and light intensity transmitted through each arm's end mirror. Again, only a short period of data may be needed for this study.

To accommodate these various needs, a convenient software structure must be set up that allows customized specification of reduced data sets. The specifications would include (as a minimum) the channels to be recorded, the decimation rate for each channel, and the time period for recording. Other extensions to the specifications might include the type of decimation filter to use on a given channel and interferometer state conditions (e.g., full lock) that should be satisfied before recording the data set.

Tasks:

In addition to setting up this structure which is geared toward creating special-purpose data sets, this subgroup should also contribute strongly to defining channel selection and decimation to be used in LIGO's standard "Lightweight Data Set" which will be recorded on-site and distributed more widely than the full data set to be archived at CACR.