## 4 Simulation And Analysis
### Setting of Experimental Parameters  
In this experiment, for constructing a simulation environment which is conducive to testing the performance of FPRDM algorithm, this paper employs the real datasets acquired from the Community Resource for Archiving Wireless Data At Dartmouth (CRAWDAD), which consists of data sets Infocom5, Infocom 6, Cambridge and Intel (Table 2), and the experimental setting of parameters is shown as Table 3.  
In particular, the movement trajectory of mobile users in the communication area is subject to the datasets in Table 2[42], because these models could be based on community division and node profiles. Furthermore, the total energy for a node is initialized to 200 J, and each data transmission consumes 0.25 J of energy. The speed for a node fluctuates from 1 to 25 m/s, which could be the mobile speed of walking, biking, or driving. As shown in Figure 4, for each type of the real data set and each group of parameter setting, a set of simulation data is generated in this experiment, therefore 24 different sets of data will be obtained from 24 simulation experiments. Because three measurement metrics in this experiment cannot reach the highest value at the same time, the delivery ration is given priority in the optimization process. Among the 24 groups of experimental data, the parameters are generally set based on the optimal group of experimental data (the highest delivery ration and relatively low delay), which is referred to the optimal performance in the 10 th experiment from Figure 4. Referring to the parameter initialization from the paradigm of fuzzy inference system and experimental results, the location and scale parameters are set as \(a_{1}=0.75\), \(a_{2}=0.5\), \(a_{3}=0.25\), and \(\sigma_{1}^{2}=\sigma_{2}^{2}=\sigma_{3}^{2}=0.96\) from the parameter settings of the 10 th experiment. In addition, based on the common settings of the opportunistic network environment, the number of nodes in this communication area \(N\) is set as 100, 200, 400 and 600, and the cache space for a node \(C\) is set as 10, 15, 20, 25, 30, 35, and 40 MB. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Dataset** & **Infocom5** & **Infocom6** & **Cambridge** & **Intel** \\ \hline Device & iMote & iMote & iMote & iMote \\ Duration (days) & 3.5 & 4 & 11 & 3.5 \\ Number of experimental devices & 41 & 98 & 50 & 8 \\ Number of internal contacts iMote & 2245 & 1706 & 1087 & 1364 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The mobility model of the simulation environment. \begin{table}
\begin{tabular}{c c} \hline \hline
**Simulation Environment** & **Description** \\ \hline Simulator & Opportunistic Network Environment (ONE) \\ Communication area & 3000 \(\times\) 3000 \\ Total simulation time (h) & 10–20 \\ Number of nodes N & 100 (initial value), 200, 400, 600 \\ Cache space of a node \(C\) (Mb) & 10 (initial value), 15, 20, 25, 30, 35, 40 \\ Speed of a node (m/s) & 1-25 \\ Initial energy for a node (J) & 200 \\ Number of social features & 8 \\ Three location parameters \(a_{1}\), \(a_{2}\), \(a_{3}\) & \(a_{1}=0.75\), \(a_{2}=0.5\), \(a_{3}=0.25\) \\ Three scale parameters \(\sigma_{1}^{2}\), \(\sigma_{2}^{2}\), \(\sigma_{3}^{2}\) & \(\sigma_{1}^{2}=\sigma_{2}^{2}=\sigma_{3}^{2}=0.96\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The experimental setting of the simulation environment. Moreover, because the social attribute information of nodes does not exist in the four real data sets, this simulation defines eight different social characteristics for each node, including interests, occupation, common friends, preferences, browsing history, repost record, comments, and online time. Each of these social features consists of several feature words, and each mobile user randomly corresponds to a different number of feature words. This simulation allocates specific feature words to each mobile node in the communication area. If a pair of nodes have more identical feature words, the opportunities of message transmission between them are even greater.