“…Once the structure is determined, parameter estimation is involved [5][6][7]. Recently, a lot of parameter estimation algorithms are proposed, including the least squares (LS) algorithm [8,9], the gradient algorithm [10,11], the particle swarm optimization algorithm, and the expectation maximization algorithm [12,13]. Among these algorithms, the LS algorithm is to find a vector that is a local minimizer to a function that is a sum of squares; thus, it is the simplest algorithm and is widely used.…”