With the rapid growth of vehicle population and vehicle miles traveled, automobile emission has become a severe issue in the metropolitan cities of China. There are policies that concentrate on the management of emiss...With the rapid growth of vehicle population and vehicle miles traveled, automobile emission has become a severe issue in the metropolitan cities of China. There are policies that concentrate on the management of emission sources. However, improving the operation of the transportation system through apps on mobile devices, especially navigation apps, may have a unique role in promoting urban air quality. Real-time traveler information can not only help travelers avoid traffic congestion, hut also advise them to adjust their departure time, mode, or route, or even to cancel trips. Will such changes in personal travel patterns have a significant impact in decreasing emissions？ If so, to what extent will they impact urban air quality？ The aim of this study is to determine how urban traffic emission is affected by the use of navigation apps. With this work, we attempt to answer the question of whether the real-time traffic information provided by navigation apps can help to improve urban air quality. Some of these findings may provide references for the formulation of urban traffic and environmental policies.展开更多
The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is ...The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.展开更多
Dear editor,This letter presents a user study to explore the effectiveness of gesture interaction in driver assistance system(DAS).Distracted driving is a specific form of driver inattention and distraction occurs whe...Dear editor,This letter presents a user study to explore the effectiveness of gesture interaction in driver assistance system(DAS).Distracted driving is a specific form of driver inattention and distraction occurs when the drivers'attention is diverted from the driving to other activities.展开更多
Long-term biopotential acquisition is of great significance for the early detection and timely treatment of various diseases.Currently,the standard silver/silver chloride(Ag/AgCl)gel electrodes may cause skin irritati...Long-term biopotential acquisition is of great significance for the early detection and timely treatment of various diseases.Currently,the standard silver/silver chloride(Ag/AgCl)gel electrodes may cause skin irritation when worn for a long time.Repeating the use of electrodes on different individuals can lead to the risk of cross-infection.Here,we propose a smart electronic tape(SET)to acquire biopotentials,in the form of a dry single-sided tape made from a combination of an ultra-stretchable conductive pattern on substrates with different functions.The high stability and durability of the patterned conductors provide accurate and timely acquisition of biopotentials,such as electrocardiograph(ECG)and electromyography(EMG).The strong adhesive behavior of the tape as well as the low-cost manufacturing process allow convenient and long-term wearing in a disposable manner.We anticipate the SET will pioneer next-gen wearable electronics for applications like disease prevention,health monitoring,and human-computer interaction.展开更多
As building-integrated photovoltaic (BIPV) facade systems are applied to the facades of high-density urban building clusters, complex dynamic shadows significantly impact the photovoltaic (PV) performance of the build...As building-integrated photovoltaic (BIPV) facade systems are applied to the facades of high-density urban building clusters, complex dynamic shadows significantly impact the photovoltaic (PV) performance of the buildings. However, existing methods for calculating building surface shadows exhibit low computational efficiency in handling complex high-density scenarios. This paper proposes a multiscale spatiotemporal selection (MSTS) calculation method for dynamic shadows in complex, high-density environments. The method eliminates irrelevant building surfaces from both spatial and temporal dimensions, and utilizes the interpolation method to reduce the number of calculations. It integrates a “direction-distance-backlit-temporal” selection model and provides an optimal sorting scheme to accelerate the preprocessing of shadow calculations. This study validates the computational efficiency and accuracy of the proposed MSTS method through two practical case studies. In Case 1, focusing on a PV facade within a complex high-density building clusters in downtown Chengdu, the method achieved a 96% reduction in computational time compared to mature commercial software and at least a 45% improvement over existing acceleration methods, with a mean absolute percentage error (MAPE) of 1.6% for the sunlit area ratio (SAR). The results indicate that, compared to existing methods, the proposed approach significantly improves computational efficiency while maintaining a high level of accuracy. In Case 2, concerning a PV facade in an industrial park in Zhuhai, a comparison with data from an on-site experimental platform yielded an SAR MAPE of 1.83% over the study period. In summary, the calculated results demonstrate a high degree of consistency with real-world observations, with only minimal deviations, thereby validating the reliability of the proposed approach. These results indicate that the proposed method can efficiently and accurately evaluate the shading effects in complex, high-density urban environments, thereby providing robust support for the performance assessment of BIPV facade systems.展开更多
文摘With the rapid growth of vehicle population and vehicle miles traveled, automobile emission has become a severe issue in the metropolitan cities of China. There are policies that concentrate on the management of emission sources. However, improving the operation of the transportation system through apps on mobile devices, especially navigation apps, may have a unique role in promoting urban air quality. Real-time traveler information can not only help travelers avoid traffic congestion, hut also advise them to adjust their departure time, mode, or route, or even to cancel trips. Will such changes in personal travel patterns have a significant impact in decreasing emissions？ If so, to what extent will they impact urban air quality？ The aim of this study is to determine how urban traffic emission is affected by the use of navigation apps. With this work, we attempt to answer the question of whether the real-time traffic information provided by navigation apps can help to improve urban air quality. Some of these findings may provide references for the formulation of urban traffic and environmental policies.
基金Smart Integration Key Technologies and Application Demonstrations of Large Scale Underground Space Disaster Prevention and Reduction in Guangzhou International Financial City([2021]–KJ058).
文摘The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2019B010149001)the National Natural Science Foundation of China(61960206007,62002018,62007001)the 111 Project(B18005)。
文摘Dear editor,This letter presents a user study to explore the effectiveness of gesture interaction in driver assistance system(DAS).Distracted driving is a specific form of driver inattention and distraction occurs when the drivers'attention is diverted from the driving to other activities.
基金supported by the National Natural Science Foundation of China(62371397,62288102,62304182,62332003,62471396)the Natural Science Foundation of Shaanxi Province(2023-JC-YB-495)the Fundamental Research Funds for the Central Universities.
文摘Long-term biopotential acquisition is of great significance for the early detection and timely treatment of various diseases.Currently,the standard silver/silver chloride(Ag/AgCl)gel electrodes may cause skin irritation when worn for a long time.Repeating the use of electrodes on different individuals can lead to the risk of cross-infection.Here,we propose a smart electronic tape(SET)to acquire biopotentials,in the form of a dry single-sided tape made from a combination of an ultra-stretchable conductive pattern on substrates with different functions.The high stability and durability of the patterned conductors provide accurate and timely acquisition of biopotentials,such as electrocardiograph(ECG)and electromyography(EMG).The strong adhesive behavior of the tape as well as the low-cost manufacturing process allow convenient and long-term wearing in a disposable manner.We anticipate the SET will pioneer next-gen wearable electronics for applications like disease prevention,health monitoring,and human-computer interaction.
基金Shenzhen University and China State Construction International Horizontal Project“Research on Key Technologies of BIM-based BIPV Design and Operation&Maintenance”(Project No.CSCI-2023-Z-8)Shenzhen University Graduate Student Innovation and Entrepreneurship Training Program,under the project titled“Research on the Energy Efficiency of Building-Integrated Photovoltaic(BIPV)Facades Systems”(Project No.868-000002020265).Additionally,the authors wish to acknowledge the contributions of all colleagues and staff at Shenzhen University and China State Construction International who provided valuable insights and assistance during the course of this study.
文摘As building-integrated photovoltaic (BIPV) facade systems are applied to the facades of high-density urban building clusters, complex dynamic shadows significantly impact the photovoltaic (PV) performance of the buildings. However, existing methods for calculating building surface shadows exhibit low computational efficiency in handling complex high-density scenarios. This paper proposes a multiscale spatiotemporal selection (MSTS) calculation method for dynamic shadows in complex, high-density environments. The method eliminates irrelevant building surfaces from both spatial and temporal dimensions, and utilizes the interpolation method to reduce the number of calculations. It integrates a “direction-distance-backlit-temporal” selection model and provides an optimal sorting scheme to accelerate the preprocessing of shadow calculations. This study validates the computational efficiency and accuracy of the proposed MSTS method through two practical case studies. In Case 1, focusing on a PV facade within a complex high-density building clusters in downtown Chengdu, the method achieved a 96% reduction in computational time compared to mature commercial software and at least a 45% improvement over existing acceleration methods, with a mean absolute percentage error (MAPE) of 1.6% for the sunlit area ratio (SAR). The results indicate that, compared to existing methods, the proposed approach significantly improves computational efficiency while maintaining a high level of accuracy. In Case 2, concerning a PV facade in an industrial park in Zhuhai, a comparison with data from an on-site experimental platform yielded an SAR MAPE of 1.83% over the study period. In summary, the calculated results demonstrate a high degree of consistency with real-world observations, with only minimal deviations, thereby validating the reliability of the proposed approach. These results indicate that the proposed method can efficiently and accurately evaluate the shading effects in complex, high-density urban environments, thereby providing robust support for the performance assessment of BIPV facade systems.
