4. Materials and methods
4.1. Architecture of the ANN models
4.1.1. Structure of the network
A multiple-input neuron is shown in Fig. 2. As shown in Fig. 2,the input vector P is represented by a rectangle on left. It is indicated that P is a single vector of R elements. These inputs go to the weight matrix W, which has R columns but only one row in this single neuron case. A constant 1 enters the neuron as an input and is multiplied by a scalar bias b. The net input to the transfer function f is n, which is the sum of the bias and the product W P. The neuron's output a is a scalar in this case. If there is more than one neuron, the network output is a vector.