## 6 Evaluation
### Evaluation Results
#### 6.3.1 Parameter Values That Meet Requirements, Relay Node Ratio
Figure 11: “The number of isolated nodes” for “relay function activation cut-off value” in “randomly selecting”. Figure 10: “Cluster split ratio” for “relay function activation cut-off value” in “randomly selecting”. Method of Selecting Nodes That Connect to Fewer Adjacent Nodes  
(Eval. 1) Compare the size of the red frame that indicates the range where no cluster split occurs (the \"cluster split ratio\" is 0%) in Figures 10, 13 and 15. In the case of \"randomly selecting\", the \"relay function activation cut-off value\" is 50% or more at a relay node density of 5.27, 60% or more at a relay node density of 3.88, 70% or more at a relay node density of 2.97, and 90% or more at a relay node density of 2.35. There were requirements where no cluster split occurred at any relay node density. In the case of \"more adjacent nodes\", cluster split did not occur when \"the number of relay nodes\" was 2, 3, or 4 at relay node densities of 5.27 and 3.88; it also did not occur when \"the number of relay nodes\" was 3 or 4 at a relay node density of 2.97, or when \"the number of relay nodes\" was 4 at a relay node density of 2.35. \"Fewer adjacent nodes\" did not cause cluster split when \"the number of relay nodes\" was 3 or 4 at relay node densities of 5.27, 3.88, or 2.97, when \"the number of relay nodes\" was 4 at a relay node density of 2.35. Figure 12: “Relay node ratio” for “relay function activation cut-off value” in “randomly selecting”. Figure 13: “Cluster split ratio” for “the number of relay nodes” in “more adjacent nodes”. Therefore, \"fewer adjacent nodes\" is more difficult to satisfy as a requirement for not causing cluster split. This is because \"fewer adjacent nodes\" relays messages to fewer nodes than \"more adjacent nodes\", so it is more likely to cause cluster split. On the other hand, \"more adjacent nodes\" can relay to more nodes than \"fewer adjacent nodes\"; then, the cluster split is less likely to occur. (Eval. 2) As shown in Figure 16, even when the relay node density is 2.35, which does not cause cluster split, the \"relay node ratio\" exceeds 70%, which is higher than the \"more adjacent nodes\" which is less than 70%. \"Fewer adjacent node\" proved to be a poor method. Method Using MPR  
(Eval. 1) With \"using MPR\", any node is not isolated or any cluster is not split, and requirements are always met. (Eval. 2) Figure 17 shows the evaluation results of \"relay node ratio\". Regardless of the relay node density, the \"relay node ratio\" is about 70%. Figure 14: “Relay node ratio” for “the number of relay nodes on” in “more adjacent nodes”. Figure 15: “Cluster split ratio” for “the number of relay nodes” in “fewer adjacent nodes”. From Figure 12, \"relay node ratio\" is approximately 90% for \"randomly selecting\", regardless of the relay node density, and \"using MPR\" is always lower. From Figure 14, for \"more adjacent nodes\", \"using MPR\" is better when the relay node density is low at 1.90, with a \"relay node ratio\" of over 70%, and \"more adjacent nodes\" is better when the relay node density is 2.35 or higher, with a \"relay node ratio\" 70%. From Figure 16, \"fewer adjacent nodes\" does not satisfy the requirements at a relay node density of 1.90, and exceeds 70% at a relay node density of 2.35. \"Using MPR\" is better when the relay node density is low, and \"fewer adjacent nodes\" is better when the relay node density is 2.97 or higher and is lower than 70%.