Mean-variance portfolio optimization models are sensitive to uncertainty in risk-return estimates, which may result in poor out-of-sample performance. In particular, the estimates may suffer when the number of assets considered is high and the length of the return time series is not sufficiently...

Based on the input-output table and the supplier-customer data disclosed by the listed companies in China, this paper builds China's production network on both industry level and firm level. We describe the characteristics of such network using various network indexes and obtain the following...

This paper employs k-means clustering, a multidimensional pattern recognition method, to categorize countries using information from five Varieties of Democracy indices. K-means country clusters are similar but not entirely identical to both k-medians clusters and arbitrary groups formed using...

Concerns are mounting over the potential for weak future growth as the Korean economy faces a wide range of structural issues including an aging society, a crisis in key regional industries, and the COVID-19 pandemic. Due to these concerns, the Korean government has established innovation growth...

Based on panel data from 41 cities in China's Yangtze River Delta region from 2003 to 2019, this article empirically has conducted an in-depth study of the impact of financial agglomeration on the level of urban economic green coordinated development and the intermediary role of innovation. The...