The effects of the correlated individual degree and susceptibility. We show and (red circles) as the function of , and the results are obtained by 500 independent realizations for each value of . Here, , the course of disease of all individuals is set as a constant value , and individual degree follows power-law distribution with exponent and . On the left, the susceptibility follows Poisson distribution with , ; on the right it follows power-law distribution with , . For comparison, we also compute and (blue squares) when the degree and susceptibility are independent correspondingly.