Fig. 3From: Long short-term memory for a model-free estimation of macronutrient ion concentrations of root-zone in closed-loop soilless culturesA structure of long short-term memory (LSTM, a) and a diagram of model training with multi-task learning (MTL, b). The abbreviation FC represents fully-connected layers, and the symbol h and σ represent the hidden layers with hyperbolic tangent and sigmoid as an activation function, respectivelyBack to article page