“…Pobability density function, Fourier transform, spectral kurtosis, autoencoder and variational autoencoder, and K-means clustering Gearbox and bearing health assessment in wind turbine system [204] Unsupervised feature selection, adapting relevance metrics with the dynamic time-warping algorithm Health indicators for a rotating machine [205] Temporal fusion separable convolutional network, a hierarchical latent space variational auto-encoder, and a regressor consisting of a linear layer and a sigmoid activation function RUL estimation on the NASA turbofan engine dataset [132,133] [206] A blockchain-based architecture that achieves trustworthy federated learning A service [207] Balanced K-star PdM in an IoT-based manufacturing system [208] HMM and reinforcement learning RUL estimation of the engines on the NASA turbofan engine dataset [132,133] An extensive application range of PdM consists of a coal crusher operating at the boiler of the real power plant and gantries in a steelworks converter, a transport line in a steelworks converter, the MW load range in a petrochemical plant, a real hybrid bus, hydraulic systems, a modular aero-propulsion system, an intelligent manufacturing system, the water pumping industry, a large gas distribution network, rolling bearings and a rotating machine, PdM for autonomous underwater vehicles (AUV), a water injection pump, wind turbine systems, the IoT-based manufacturing environment, hard disk drives, the turbofan engine, the drilling machine of an automotive manufacturer, solar photovoltaic energy systems, maintenance work orders, manufacturing, and structural health monitoring.…”