How is the F1 score calculated in the context of the LSTM RNN-based FDI detectors, and what do true positive, true negative, false positive, and false negative represent?

The F1 score is calculated using the harmonic mean of precision and recall: F1 = 2 × (Pr × Re) / (Pr + Re). Precision is TP/(TP+FP) and recall is TP/(TP+FN). In the LSTM RNN-based FDI detector, a true negative represents a correctly detected assault measure, a true positive represents an accurately discovered regular observation, a false positive represents a mistakenly observed assault, and a false negative represents a missed assault.