||Hidemichi Fujii, Akihiko Shinozaki, Shigemi Kagawa, Shunsuke Managi, How Does Information and Communication Technology Capital Affect Productivity in the Energy Sector? New Evidence from 14 countries Considering the Transition to Renewable Energy System., Energies, 10.3390/en12091786, 12, 9, 2019.05, Abstract
By focusing on a distributed energy system that has been widely diffused for efficient utilization of renewable energy generation in recent years, this paper investigates the relationship between productivity growth and information and communications technology capital in the energy sector. Information and communications technology is a key factor in operating distributed energy systems in a way that balances energy supply and demand in order to minimize energy loss and to enhance capacity utilization. The objective of this study is to clarify the determining factors that affect productivity growth, focusing on three different information and communications technologies: information technology capital, communication technology capital and software capital. Our estimation sample covers energy sectors in 14 countries from 2000 to 2014. The results show that information technology and software capital contribute to increasing material productivity and capital productivity in the energy sector, respectively. Meanwhile, communication technology capital negatively affects these two productivity indicators..
||Hidemichi Fujii, Kazuyuki Iwata, Andrew John Chapman, Shigemi Kagawa, Shunsuke Managi, An analysis of urban environmental Kuznets curve of CO2 emissions
Empirical analysis of 276 global metropolitan areas, Applied Energy, 10.1016/j.apenergy.2018.06.158, 228, 1561-1568, 2018.10, This study analyzed the relationship between urban CO<sub>2</sub> emissions and economic growth applying the environmental Kuznets curve hypothesis. The objective of this study is to investigate how urban CO<sub>2</sub> emissions and their composition have changed with urban economic growth, depending on city characteristics, using a dataset of metropolitan areas. We obtained data for 276 cities in 26 countries for the years 2000, 2005, and 2008. The dataset includes urban CO<sub>2</sub> emissions, GDP, and population. Additionally, data regarding compact city variables are applied to determinants analysis using an econometric approach. The results demonstrate an inverted U-shape relationship between urban CO<sub>2</sub> emissions and urban economic growth. Additionally, an inverted U-shape relationship is observed for the transport and residential & industry sectors. However, the turning points of each inverted U-shape curve varies. This result implies that we can better understand urban policies for reducing urban CO<sub>2</sub> emissions by considering the characteristics of each sector..
||Fujii, H., Managi, S., Trends and priority shifts in artificial intelligence technology invention: A global patent analysis, Economic Analysis and Policy, 10.1016/j.eap.2017.12.006, 58, 60-69, 2018.05, This study is the first to apply a decomposition framework to clarify the determinants of AI technology invention. Consisting of 13,567 AI technology patents for the 2000–2016 period, our worldwide dataset includes patent publication data from the U.S., Japan, China, Europe, and the Patent Cooperation Treaty (PCT). We find that priority has shifted from biological and knowledge-based models to specific mathematical models and other AI technologies, particularly in the U.S. and Japan. Our technology type and country comparison shows that the characteristics of AI technology patent publication differ among companies and countries..
||Fujii, H., Okamoto, S., Kagawa, S., Managi, S., Decomposition of toxicity emission changes on the demand and supply sides: empirical study of the US industrial sector, ENVIRONMENTAL RESEARCH LETTERS, 10.1088/1748-9326/aa9c66, 12, 12, 2017.12, This study investigated the changes in the toxicity of chemical emissions from the US industrial sector over the 1998–2009 period. Specifically, we employed a multiregional input–output analysis framework and integrated a supply-side index decomposition analysis (IDA) with a demand-side structural decomposition analysis (SDA) to clarify the main drivers of changes in the toxicity of production- and consumption-based chemical emissions. The results showed that toxic emissions from the US industrial sector decreased by 83% over the studied period because of pollution abatement efforts adopted by US industries. A variety of pollution abatement efforts were used by different industries, and cleaner production in the mining sector and the use of alternative materials in the manufacture of transportation equipment represented the most important efforts..