sustainability Article An Empirical Analysis on DPRK: Will Grain Yield Influence Foreign Policy Tendency? 1,3, 2,3, , 4, , Chi Zhang y, Jun He * y and Guanghui Yuan * y 1 School of Government, Shanghai University of Political Science and Law, Shanghai 201701, China;
[email protected] 2 Shanghai Research Center for Students’ Safety Education, Shanghai 200032, China 3 Kunming New Times Research Institute for the Protection of Oversea Interests and Security Studies, Kunming 650500, China 4 Fintech Research Institute, School of Information Management and Engineering, Shanghai University of Finance and Economics, Shanghai 200433, China * Correspondence:
[email protected] (J.H.);
[email protected] (G.Y.); Tel.: +86-21-3922-7387 (G.Y.) All the authors contributed equally to this work. y Received: 19 February 2020; Accepted: 18 March 2020; Published: 30 March 2020 Abstract: Democratic People’s Republic of Korea is the hub of Northeast Asia and its geopolitics is of great significance, whose foreign policy trend is not only related to the peace and stability of the region, but also one of the major variables affecting cooperation in Northeast Asia. According to the data on North Korea’s grain yield collected by the Korea National Statistical Office, supplemented by the data on international food aid to North Korea collected by the World Food Programme, and combined with the judgment of 10 experts from China, South Korea and the United States on the Hawk and Dove Index of North Korea’s foreign policy from 1990 to 2018, we use empirical mode decomposition wavelet transform data analysis and feature extraction methods to study the impact relationship, and OLS regression analysis to study the actual cycle of transformation.