World Power Trends and International Relations: Measuring Power with an Entropy-QAP Approach

National power has been an important discriminative signal for the evolution of great power competition and international patterns in recent years, not only in terms of the relative resource scale of the state but also in terms of the efficiency of resource use. Based on the two levels of national resources and conversion mechanisms, this article uses the entropy method to establish national power comprehensive assessment index systems covering 144 countries and 38 indicators from 1990-2020. At the same time, based on power transition theory (PTT), this article uses quadratic assignment procedures to verify the relevance and interpretation of international bilateral relations in the national power gap. The conclusion is that technology and economic elements are especially important for national power, and the conversion mechanism is icing on the cake rather than a decisive factor. The competition among great powers is transformed into nontraditional competition rather than an arms race; the international pattern has gradually developed from one superpower to a multipolar trend, and the global economic and geopolitical center has transitioned to Asia. The rise of China and the recession in the U.S. are factual; as the gap between the two countries' power narrows, their international relations become increasingly tense, confirming power transition theory.