Algorithm 2: The vice cluster-head election

Input: all member nodes and their primary cluster-heads within K clusters Output: all vice cluster-heads in the set C2 ----------------------------------------------------------------------------------------------------------------- (1) For each cluster (2)     For member nodes in the same cluster except the primary cluster-head (3)          Calculate the residual energy objective function $f_1(i)$ and the distance function $f_3(i)$ of each node, respectively (4)               If the sum of residual energy of all nodes is greater than half of the initial energy of the network (0.5 * n$E_0$) (5)                 Calculate the node adaptation function value according to $Q(i)$ = 1/2 $*f_1(i)$ + ½ * $f_3(i)$ (6)               Else (7)                   Calculate the node adaptation function value according to$Q(i)$ = $\frac{E_{res}\left(i\right)}{E_0}*f_1(i)$ + (1 − $\frac{E_{res}\left(i\right)}{E_0}$)/2 * $f_3(i)$ (8)      Find the node with the largest fitness function value and save this node in formation in the set C2 (9) End