Figure 7: The network lifetime of running the CKN algorithm and the EC-CKN algorithm, respectively. In (a), the ten lines of the lifetime results according to the CKN algorithm have a lot intersections, which means the energy consumption by the CKN algorithm in a WSN is not managed towards the energy-balancing direction. However, in (c), the ten lines of the lifetime results by the EC-CKN algorithm present smooth changing when the number of nodes and the value of are changed and the lifetime increases when the ratio increases. This point clearly reflects that the energy consumption by the EC-CKN algorithm in a WSN is well managed towards the energy-balancing direction. Furthermore, simulation results in (b) and (d) also reveal that decreasing the value of (let more nodes sleep) can definitely help to prolong the network lifetime of the EC-CKN algorithm in a WSN, but not the CKN algorithm.