## 5 Protocol Performance Evaluation
### Simulation Results Presentation  
In total, 360 simulation tests were performed. In these tests the performance of SHPER protocol was investigated versus that of TEEN protocol, over different network topologies and various values of initial node energy and locations of the base station. More specifically, the number of nodes remaining alive over time was simulated for both protocols for the cases that the distance between the base station and the network field is either 100 m, or 200 m or 300 m.  
Moreover, the average percentages of the first node depletion time increase, the last node depletion time increase and the energy consumption decrease provided by using SHPER instead of TEEN, were calculated by using the Central Limit Theorem with 95% confidence intervals [28]. In the related figures, the upper, lower and central bars denote the upper bound, the lower bound and the center of the confidence intervals respectively. In the first half of the simulation tests, all of the nodes were considered to have their initial energy \(Er_{l}(0)\) set to 0.5 J. The related simulation results concerning the number of nodes remaining alive over time are graphically displayed in Figures 4, 5 and 6.  
Figure 4: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN [\(Er_{l}(0)=0.5\) J, \(D=100\) m].  
Figure 5: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN, [\(Er_{i}(0)=0.5\) J, \(D=200\) m].  
Figure 6: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN [\(Er_{i}(0)=0.5\) J, \(D=300\) m].  
In the last half of the simulation tests, the sensor nodes were considered to have their initial energy \(Er_{t}(0)\) taking random values between 0.1 J and 0.5 J. The resultant simulation results concerning the number of nodes remaining alive over time are graphically displayed in Figures 10, 11 and 12.  
Figure 10: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN [\(Er_{t}(0)\) \(\in\) [0.1,0.5] J, \(D=100\) m].  
Figure 9: Percentage of average decrease of energy consumption in SHPER opposed to TEEN over the distance of the base station from the WSN field [\(Er_{t}(0)=0.5\) J].  
Similarly, the related average percentages of the first node depletion time increase, the last node depletion time increase and the energy consumption decrease are depicted in Figures 13, 14 and 15.  
Figure 11: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN [\(Er_{I}(0)\) \(\in\) [0.1,0.5] J, \(D=200\) m].  
Figure 12: Comparative depiction of the nodes remaining alive over the simulation time steps in SHPER and TEEN [\(Er_{I}(0)\) \(\in\) [0.1,0.5] J, \(D=300\) m].  
Figure 14: Percentage of average increase of the time the last node depletes in SHPER opposed to TEEN over the distance of the base station from the WSN field (\(Er_{A}(0)\in[0.1,0.5]\) J).  
Figure 13: Percentage of the average increase of the time the first node depletes in SHPER opposed to TEEN over the distance of the base station from the WSN field (\(Er_{A}(0)\in[0.1,0.5]\) J).