Spatial Dynamics of the Communities and the Role of Major Countries in the International Rare Earths Trade: A Complex Network Analysis

External supply risk of agricultural products trade along the Belt and Road under the background of COVID-19

Agricultural product trade along the Belt and Road (B&R) is an important part of the international food security system, the vulnerabilities of which have been highlighted by the recent COVID-19 pandemic. Based on the complex network analysis, this study analyzes the characteristics of agricultural products trade network along the B&R. It also combines the effects of COVID-19 with the import trade volume of agricultural products in countries along the B&R to build a risk supply model of agricultural products. The results show that: (1) In 2021, the spatial correlation structure of agricultural products trade along the B&R became increasingly sparse, and the network connectivity and density also decreased. (2) The network showed obvious scale-free distribution characteristics and obvious heterogeneity. Five communities emerged under the influence of the core node countries, but the formation of community in 2021 had obvious geopolitical characteristics. (3) Under the influence of the COVID-19 epidemic, the number of countries with medium-risk and high-risk level along the route facing external dependence risk (R_EDI), import concentration risk (R_HHI) and COVID-19 epidemic risk (R_RICI) increased in 2021, and the number of countries with extremely low-risk level decreased. (4) The dominant risk type of external supply of agricultural products along the route changed from compound risk type in 2019 to epidemic risk in 2021. Hence, the results can be expected to prevent external risk impact from reducing excessive concentration of agricultural products trade and excessive dependence on the external market.

Assessing the structural connectivity of international trade networks along the "Belt and Road"

Assessing the trade network connectivity is essential for understanding the trade network structure, optimizing trade development patterns, and improving uneven trade development along the "Belt and Road" (BRI). From the perspective of connectivity, this paper integrates the frontier algorithms in network science and constructs an analytical framework to identify the mesoscale structures, including the community structure, core-periphery structure, and backbone structure embedded in the network, and further explore the structural connectivity of the BRI trade network. The results show that: (1) The BRI trade network represents a trade pattern of "one superpower, many great powers", with three major trade groups in Southeast Asia, the Middle East, and Northern Central and Eastern Europe in terms of geographical space. China is the super core of the BRI trade network, and the most considerable trade links are all centred in China. (2) Five distinctive trade blocs have formed in the BRI trade network. Nevertheless, the structure of the trade blocs shows significant geographical proximity, indicating that geographical distance still plays a vital role in the international trade system at the regional scale. (3) The BRI trade network demonstrates a significant core-periphery structure, with apparent trade clustering among the core countries within the trade network. Among them, nine countries led by China constitute the core structure, and the peripheral structure is large, reaching forty-four. (4) The trade links with China constitute the backbone structure of the whole trade network in the BRI region. In addition, the trade links related to energy trade and re-export trade are also crucial components of the BRI backbone structure. Methodologically, the analytical framework proposed for assessing the network structural connectivity has great potential to be widely applied to other disciplines and fields.

Material Flow Patterns of the Global Waste Paper Trade and Potential Impacts of China's Import Ban

Waste paper, an essential substitute for wood and other plant-based fibers in paper making, is an indispensable part of the circular economy; yet, the impacts of China's ban on global waste paper cycles have not been well understood. We modeled the evolution of the global waste paper trade network during 1995-2019. We found that the cumulative trade volume of global waste paper reached 1010 million tons in the last 25 years and showed a downward trend since 2015. The global import center of waste paper experienced a transfer from Europe to East Asia and then to Southeast Asia. The ban has stimulated some developed countries to reduce the exports of unsorted waste paper since 2017, but for many major importers their changes in waste paper trade patterns were related to waste paperboard, which was not banned by China, suggesting that this import change trend may be inevitable and irrespective of China's ban. Besides, India has replaced China to become a new import hub of unsorted waste paper. Our results lay a foundation for exploring the evolution of the future global solid waste cycle under the background of zero import of solid waste increasingly implemented by China and many other developing countries.

How environmental regulation affects China's rare earth export?

China's rare earth export trade has developed so rapidly since 1990s that China has gradually occupied a leading position in the international market. However, this fast development was proceeding at the cost of the rare earth energy consumption and environmental devastation. Now China begins to attach great importance to environmental protection, which attracts many researchers. This study aims to analyze the influence of environmental regulation on China's rare earth export trade. And the original study is amongst the few to examine the relationship between environmental regulation and China's rare earth export with the product-level data. Different from previous studies, this paper selects China's rare earth export data from 1995 to 2015 and introduces product heterogeneity based on the rare earth production process. Moreover, this study uses the entropy weight method to measure the intensity of environmental regulation. The core conclusions are as follows: (1) Environmental regulation significantly promotes rather than restrains China's rare earth export. (2) According to the rare earth production process, this paper divides rare earth products into 3 kinds, that is, rare earth raw materials, rare earth useful components and rare earth end-use applications. Then, it is found that rare earth useful component export in processing and smelting is positively affected by environmental regulation. Rare earth raw materials and end-use applications in China's export are hardly affected. (3) Technological innovation has a mediating effect on the impact mechanism of environmental regulation on China's rare earth export, which means that environmental regulation significantly promotes technological innovation of enterprises, and thereby the rare earth export is increased. The findings are helpful for policymakers to resolve the issue of environmental devastation.

Spatial-temporal variation characteristics and evolution of the global industrial robot trade: A complex network analysis

Industrial robots are a strategic future technology and an important part of the development of artificial intelligence, and they are a necessary means for the intelligent transformation of manufacturing industry. Based on global industrial robot trade data from 1998 to 2017, this paper applies the dynamic complex network analysis method to reveal the spatial and temporal variation characteristics and trade status evolution of the global industrial robot trade network. The results show that the global industrial robot network density has steadily increased, and the industrial robot trade has been characterized by ‘diversification’. The number of major industrial robot exporters in the world is increasing, and the import market is increasingly diversified. The export market structure is relatively tight, the centrality of the global industrial robot trade network shows a downward trend, and the dissimilarity of the ‘core-edge’ clusters decreases year by year. The trade status of ‘catch-up’ countries represented by China has rapidly increased. However, Japan, Germany, and Italy are still in the central position of the industrial robot trade. Moreover, trade of the ‘catch-up’ countries’ is dominated by imports, and exports of industrial robot products are insufficient. Finally, policy suggestions are provided according to the results.

Complex network analysis of bilateral international investment under de-globalization: Structural properties and evolution

As many countries are now seeking to protect their own markets rather than indulge in global trade, this paper examines whether this type of de-globalization behavior has been having any effect on international investment relationships through a systematic analysis of international investment network (IIN) in 127 economies from 2005 to 2016. Unlike previous studies that only analyzed portfolio investment data, the bilateral international investment data were estimated using a matrix-based iteration approach, and the IIN established using complex network theory. Using bilateral international investment data made the results more reliable and somewhat closer to reality. To analyze the structural properties and evolution of the IIN, complex network indicators including a new one named node similarity were developed. The node similarity is defined as the proportion of common relationships of the current economy between two successive years which is useful to reveal the dynamics of the IIN. This paper finds that there are heterogenous and hierarchal properties in the IIN, several economies had a wide range of international investment partners, while most others had only a small range of investment partners and were more likely to form tight groups within the network. The economies in the IIN were tending towards smaller but closer communities, a new trend of regional financial cooperation was developing. The IIN is divided into more communities over time while the top active and central economies often locate in different communities. These findings imply that the structure of the IIN is changing geographically during the de-globalization rather than independent with regions. The regional cooperation has made positive effect on the international investment. The governments should ensure that they continue to support liberal financial policies and to promote better regional financial cooperation.

Measuring directional urban spatial interaction in China: A migration perspective

The study of urban spatial interaction is closely linked to that of economic geography, urban planning, regional development, and so on. Currently, this topic is generating a great deal of interest among researchers who are striving to find accurate ways to measure urban spatial interaction. Classical spatial interaction models lack theoretical guidance and require complicated parameter-adjusting processes. The radiation model, however, as proposed by Simini et al. with rigorous formula derivation, can simulate directional urban spatial interaction. We applied the radiation model in China to simulate the directional migration number among 337 nationwide research units, comprising 4 municipalities and 333 prefecture-level cities. We then analyzed the overall situation in Chinese cities, the interaction intensity hierarchy, and the prime urban agglomerations from the perspective of migration. This was done to ascertain China's urban spatial interaction and regional development from 2000 to 2010 to reveal ground realities.