Table 3: Performance measures and their definitions.

MetricsCalculation

RMSE R M S E = 3 0 𝑖 = 1 ( 𝑇 𝑖 𝑃 𝑖 ) 2 / 3 0
MAD M A D = 3 0 𝑖 = 1 | 𝑇 𝑖 𝑃 𝑖 | / 3 0
MAPE M A P E = 3 0 𝑖 = 1 | ( 𝑇 𝑖 𝑃 𝑖 ) / 𝑇 𝑖 | / 3 0
RMSPE R M S P E = 3 0 𝑖 = 1 ( ( 𝑇 𝑖 𝑃 𝑖 ) / 𝑇 𝑖 ) 2 / 3 0

N o t e that 𝑇 and 𝑃 represent the actual and predicted failure time, respectively.