Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values...Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.展开更多
This review highlights the recent advancements in Mg research in South Korea with a prime focus on high-speed-extrudable Mg–Bi-based alloys for high productivity and strength, innovative techniques utilizing {10–12}...This review highlights the recent advancements in Mg research in South Korea with a prime focus on high-speed-extrudable Mg–Bi-based alloys for high productivity and strength, innovative techniques utilizing {10–12} twinning for improved mechanical properties, and alloying and processing methods for enhanced corrosion resistance. High-alloyed Mg–Bi-based alloys possess thermally stable α-Mg matrix and secondary phase, which ensures high-speed extrusion of these alloys at elevated temperatures without hot cracking. Consequently, they exhibit outstanding extrudability with a maximum extrusion speed of up to 70 m/min. Furthermore, their high alloying contents offer excellent strength even after high-speed extrusion through strong solid solution hardening and particle hardening effects, making them suitable for high-performance extruded Mg products. The pre-twinning process utilizing {10–12} twinning and the combined process of pre-twinning and subsequent annealing have shown promise in controlling microstructure and texture of wrought Mg alloys and thus enhancing their mechanical properties. The pre-twinning process enhances tensile strength, fatigue properties, and age-hardening rate of Mg alloys. Furthermore, the combined processes of pre-twinning and subsequent annealing considerably improve their ductility, stretch formability, bending formability,and damping capacity. Efforts have been made to improve the corrosion resistance of Mg alloys through alloying additions, process treatments,and surface coatings. Alloying elements like Ca, Sc, and Sm alter the microstructural features(such as secondary phases and grain size)that affect the corrosion phenomenon. Process treatments such as multidirectional forging, screw rolling, and pulse electron beam can also improve the corrosion resistance by refining the microstructure. Furthermore, advanced surface coating technologies can create durable and corrosion-resistant layers for effectively protecting the Mg alloys. All these research activities conducted in South Korea have considerably contributed to the widespread utilization of Mg alloys in diverse applications by overcoming the inherent limitations of Mg alloys such as low extrudability, formability, and corrosion resistance.展开更多
This paper provides an overview of South Korea’s 20-year journey in adopting building information modeling(BIM) and future direction. It first discusses the six phases of BIM adoption in South Korea, starting from th...This paper provides an overview of South Korea’s 20-year journey in adopting building information modeling(BIM) and future direction. It first discusses the six phases of BIM adoption in South Korea, starting from the use of BIM as a marketing tool to its current intelligent BIM phase. The government’s support for BIM-related research and development projects is also highlighted, with a focus on the artificail intelligence (AI)-based architectural design automation project. As the future direction, it explores the integration of AI with BIM in both local and global contexts. The paper presents AIpowered architectural design methods, including AI-powered early architectural design generation and architectural detailing.Compared to AI-based early architectural design generation, architectural detailing is an unexplored research topic. This paper introduces two AI-and BIM-based architectural detailing methods, being developed at Yonsei University:namely,BIM library transplant and Natural language-based Architectural Detailing through Interaction with AI (NADIA). These methods demonstrate how AI-enhanced BIM can enable architects to interactively develop building details using a language model as a conversational AI and a knowledge base, and a BIM authoring tool as a design platform, in the near future.展开更多
基金supported by the National Institute of Forest Science(Project No.FM0800-2019-05)。
文摘Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.
基金supported by the National Research Foundation of Korea (NRF) (grant no.2019R1A2C1085272) funded by the Ministry of Science,ICTFuture Planning (MSIP,South Korea)+1 种基金in part supported by the Ministry of Science and Higher Education of the Russian Federation for financial support under the Megagrant (Grant No.075-15-2022-1133)the NRF (grant no.2015R1A2A1A01006795) funded by the MSIP of South Korea through the Research Institute of Advanced Materials。
文摘This review highlights the recent advancements in Mg research in South Korea with a prime focus on high-speed-extrudable Mg–Bi-based alloys for high productivity and strength, innovative techniques utilizing {10–12} twinning for improved mechanical properties, and alloying and processing methods for enhanced corrosion resistance. High-alloyed Mg–Bi-based alloys possess thermally stable α-Mg matrix and secondary phase, which ensures high-speed extrusion of these alloys at elevated temperatures without hot cracking. Consequently, they exhibit outstanding extrudability with a maximum extrusion speed of up to 70 m/min. Furthermore, their high alloying contents offer excellent strength even after high-speed extrusion through strong solid solution hardening and particle hardening effects, making them suitable for high-performance extruded Mg products. The pre-twinning process utilizing {10–12} twinning and the combined process of pre-twinning and subsequent annealing have shown promise in controlling microstructure and texture of wrought Mg alloys and thus enhancing their mechanical properties. The pre-twinning process enhances tensile strength, fatigue properties, and age-hardening rate of Mg alloys. Furthermore, the combined processes of pre-twinning and subsequent annealing considerably improve their ductility, stretch formability, bending formability,and damping capacity. Efforts have been made to improve the corrosion resistance of Mg alloys through alloying additions, process treatments,and surface coatings. Alloying elements like Ca, Sc, and Sm alter the microstructural features(such as secondary phases and grain size)that affect the corrosion phenomenon. Process treatments such as multidirectional forging, screw rolling, and pulse electron beam can also improve the corrosion resistance by refining the microstructure. Furthermore, advanced surface coating technologies can create durable and corrosion-resistant layers for effectively protecting the Mg alloys. All these research activities conducted in South Korea have considerably contributed to the widespread utilization of Mg alloys in diverse applications by overcoming the inherent limitations of Mg alloys such as low extrudability, formability, and corrosion resistance.
基金funded by the Civil Engineering Graphics Branch of China Graphicsthe Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land,Infrastructure and Transport (Grant RS-2021-KA163269)。
文摘This paper provides an overview of South Korea’s 20-year journey in adopting building information modeling(BIM) and future direction. It first discusses the six phases of BIM adoption in South Korea, starting from the use of BIM as a marketing tool to its current intelligent BIM phase. The government’s support for BIM-related research and development projects is also highlighted, with a focus on the artificail intelligence (AI)-based architectural design automation project. As the future direction, it explores the integration of AI with BIM in both local and global contexts. The paper presents AIpowered architectural design methods, including AI-powered early architectural design generation and architectural detailing.Compared to AI-based early architectural design generation, architectural detailing is an unexplored research topic. This paper introduces two AI-and BIM-based architectural detailing methods, being developed at Yonsei University:namely,BIM library transplant and Natural language-based Architectural Detailing through Interaction with AI (NADIA). These methods demonstrate how AI-enhanced BIM can enable architects to interactively develop building details using a language model as a conversational AI and a knowledge base, and a BIM authoring tool as a design platform, in the near future.
