互惠(文化人类学)
聚类系数
聚类分析
节点(物理)
理论(学习稳定性)
复杂网络
对比度(视觉)
数学
国际贸易
计算机科学
经济
统计
组合数学
物理
心理学
社会心理学
量子力学
机器学习
人工智能
作者
Haoran Li,Lijie Sun,Wei‐Xing Zhou
出处
期刊:International Journal of Modern Physics C
[World Scientific]
日期:2022-11-19
卷期号:34 (05)
被引量:1
标识
DOI:10.1142/s0129183123500687
摘要
International seed trade networks (iSTNs) are complex networks formed by the trade of seeds between economies. We investigate the statistical properties of the international trade networks for maize seeds and rice seeds from the viewpoint of temporal directed and weighted networks. We find that most properties, including node and edge numbers, average in- and out-degrees, total and average trade values, network density and clustering coefficient, showed an increasing trend, which indicates that the increasing globalization of seed trade has led to more and more complete and dense trade networks. We also find that links with larger trade values have greater stability. In addition, we observe positive correlations between in-degree and out-degree, link reciprocity and in- and out-degrees, link reciprocity and in- and out-strengths and clustering coefficient and in- and out-degrees. In contrast, there are negative correlations between clustering coefficient and in- and out-strengths. Furthermore, we find that both networks are assortatively mixed in most years, which indicates that large exporters and importers are more likely to trade with other large exporters and importers. The structural properties of the two iSTNs of maize and rice share many qualitative similarities, but exhibit quantitative differences.
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