An alarm system is optimal if it detects catastrophes with a certain high probability and simultaneously gives a minimum number of false alarms. In a general context an optimal alarm system is derived and then the method is applied to Gaussian processes.
"Optimal Prediction of Catastrophes with Applications to Gaussian Processes." Ann. Probab. 8 (4) 841 - 850, August, 1980. https://doi.org/10.1214/aop/1176994670