“…As an extension of real-valued neural networks, the complex-valued neural networks (CVNNs) have received increasing interests [3,4,6,7,10,11,12,13,14,16,17,26,27,28,29,33,37,38,43,45,46,47,48]. CVNNs, in which the states, connection weights, or activation functions are complex-valued, have more complicated properties than the real-valued NNs and have shown their advantages in real applications, e. g., solving DOI: 10.14736/kyb-2018-4-0844 the XOR problem and the detection of symmetry problem [7,10,17,26,28,43].…”