## 4 Data Collection
### Data Clustering Analysis
#### 4.1.1 Clustering Scenario, I (Tourist Nationalities)  
This scenario aims to create clusters of nationalities regardless of the tourism agencies who arranged trips. The option of single linkage algorithm was used to process the collected data for the year 2019 to be used as an example. In the literature, there is no optimal number of clusters which can be used to have a meaningful number of clusters results. The process starts by selecting the number of clusters (n = 3), then, applying the clustering algorithm shown in Figure 3.  
Figure 3: Flowchart describes steps used to determine number of clusters. Each month through the year 2019, the procedure described in the described flow chart was conducted using different clustering numbers (n). At each time, the outcome of clustering was analyzed in terms of its impact on economic, health, social, sustainability, and administration aspects. In order to analyze the content of the clusters, the clusters are named A, B, C, etc. As an example, the content of clusters when n = 10 for January 2019 is presented in Table 1 and the corresponding dendogram is shown in Figure 4.  
The dendrogram in Figure 2 shows the hierarchal relationship between objects (variables), that will be used to form clusters (in this scenario: nationalities) on the horizontal \begin{table}
\begin{tabular}{c c c} \hline \hline
**Month** & **Clusters** & **Nationalities** \\ \hline \multirow{8}{*}{January, 2019} & \multirow{8}{*}{A} & American, Italian, British, Chinese, Japanese, Spanish, Argentinean, Mexican, Brazilian \\  & & Romanian, Singapore, Cypriot, Greek, Israeli, Netherlands, Asian And The Pacific, \\  & & European, Swiss, Polish, Bulgarian, Danish, Turkish \\ \cline{2-3}  & \multirow{8}{*}{B} & Malaysian \\ \cline{2-3}  & & C & Indonesian, French, Indian, Thai, Palestinian, Costa Rica, Ukrainian, Kuwait, Myanmar \\ \cline{2-3}  & \multirow{8}{*}{D} & Canadian, Korean, Chilean \\ \cline{2-3}  & & E & German, Austrian, Sri Lankan \\ \cline{2-3}  & & F & Dutch \\ \cline{2-3}  & & G & Filipino \\ \cline{2-3}  & & H & Russian, Colombian, Irish \\ \cline{2-3}  & & I & Australian, Belgian \\ \cline{2-3}  & & J & Portuguese, Saudi, New Zealand \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Clusters content when the number of clusters is equal to ten (N = 10). Figure 4: Dendrogram for January, 2019 using single linkage clustering algorithm when N = 10 (scenario I). axis, and the similarity coefficient used to create clusters between its variables (nationalities) on the vertical axis. In general, the shorter the height of the link that joins two variables together, then these two variables are the most similar. The link height indicates the order in which the clusters were joined. For example, the dendogram suggests that Americans and Italians are much closer to each other than Americans and the Chinese. In each cluster, the distribution of different nationalities was studied within six geographical regions, namely these regions are: Oceania, the Middle East and Arab countries, Asia, Europe, America, and Africa, by determining percentage of tourists who hold the nationalities of countries belonging to a particular region. To facilitate visual perception of the distribution, distinct colors were used for each region, and the contents of each colored group were displayed using a bar chart where each column represented a cluster. When the number of colors in the cluster is less, it means that there is more homogeneity in the contents of the cluster. The ideal situation is to have one color in each column. Figure 5 shows the bar chart for the clusters regions distribution (CRDC) when N = 10, January 2019. It shows that clusters B, F, and G have nationalities from the same regions, whereas clusters D, E, H, I, and J have nationalities from two different regions. Clusters A and C have more than three different nationalities. Gathering tourists coming from a specific geographical area into one group has positive repercussions in many aspects.