Table 1.
Number of communities.
Fig 1.
Communities of the weighted and unweighted network of 2014.
(A) The nodes in the figure indicate the countries. (B) The links represent the trade relationships between two countries. (C) The thicknesses of links show the value of the trade between two countries. (D) The arrow represents the direction of the trade flow. (E) The nodes in the same color are in the same communities.
Fig 2.
(A) The black line shows the value of modularity in the weighted network. (B) The red line indicates the value of modularity in the unweighted network.
Fig 3.
World maps of communities’ evolution.
(A) The maps show the international RE trade communities’ evolution from 2002–2014. (B) The countries in the same color are in the same communities. (C) The weighted maps on the left side represent the communities division based on the trade value or weight. (D) The unweighted maps on the right side indicates the communities division without consideration of trade value or weight. Note: The authors performed Fig 3 based on the Fig 4 of [25] using CorelDRAW software with their new statistical data.
Fig 4.
(A) The black line shows the NMI in the weighted network. (B) The red line indicates the NMI in the unweighted network.
Fig 5.
Migration of major countries in 2002–2003.
(A) The red circle indicates the communities in 2002. (B) The blue circle represents the communities in 2003. (C) The arrow shows the movement direction of the countries between communities in the period of 2002–2003. (D) The communites above blue thick arrow represent the communities that are new formed and did not participate the international RE trade before.
Fig 6.
Migration of major countries in 2011–2012.
(A) The red circle indicates the communities in 2011. (B) The blue circle represents the communities in 2012. (C) The arrow shows the movement direction of the countries between communities in the period of 2011–2012.
Fig 7.
Weighted degree value evolution.
(A) The lines in different colors indicate the weighted degree value ranking index evolution of different countries.
Fig 8.
Weighted in degree value evolution.
(A) The lines in different colors indicate the weighted in degree value ranking index evolution of different countries.
Fig 9.
Weighted out degree value evolution.
(A) The lines in different colors indicate the weighted out degree value ranking index evolution of different countries.
Table 2.
Averages of the ranking indices.
Fig 10.
Division of the RE trade group.
(A) Group 1 in a green circle defined as leaders includes China, Japan, the United States, and Germany. (B) Group 2 in a green circle defined as challengers includes Austria, UK, France, Norway, Brazil, Hong Kong, Belgium, Korea, and India. (C) Group 3 in a green circle defined as potential leader includes Vietnam. (D)Group 4 in a green circle defined as followers includes other countries.
Table 3.
China’s RE trade situation.
Table 4.
Japan’s RE trade situation.
Table 5.
USA’s RE trade situation.
Table 6.
Germany’s RE trade situation.
Table 7.
Viet Nam’s RE trade situation.
Table 8.
Group of challengers and followers in the RE trade situation in 2014.