Saturday, May 21, 2005

GravStat 2005: Prodi

Time-coincidence search using bar detectors (IGEC). Template search - matched filters optimized for short and rare transients.
Many trials at once (9 pairs + 7 triples + 2 4-folds). Many target thresholds. Directional/non-directional searches.
Control of false dismissal probability - balance between detection efficiency and background fluctuations.
Background noise estimation - 10^3 time lags for pairs, 10^4-10^5 time lags for triples. GOF tests with background model.
Blind analysis - tuning of procedures before looking at data (no playground).
IGEC-2 has agreed on blind data exchange (secret time lag).
Resample by shifting event time series to get statistics of accidental claims.
Realized that technique good for upper limits but optimized for discoveries - false possitives hide true discoveries. Need to decrease false alarm probability (type I error).
Want to build confidence belt based on false alarm probability for each value of unknown parameter. Use Benjamini & Hochberg FDR procedure.
Open questions:
Check fluctuation of random variable FDR with respect to mean
Are we required to report a rejection of the null hypothesis ? - this is claim for an excess correlation in the observations at the true time, not taking into account measured noise background at different time lags - it might not be GW.

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