Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by l...Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.展开更多
研究旨在探讨库容测量中的新技术应用,提出了一种基于机载LiDAR(Light Detection and Ranging)系统和无人船单波束测深系统联合技术的测量框架。通过建筑信息模型(Building Information Modeling,BIM),将水库陆上与水下地形数据进行融...研究旨在探讨库容测量中的新技术应用,提出了一种基于机载LiDAR(Light Detection and Ranging)系统和无人船单波束测深系统联合技术的测量框架。通过建筑信息模型(Building Information Modeling,BIM),将水库陆上与水下地形数据进行融合构建水库地形模型,实现精确的库容测量。以安徽省某水库为例,实验结果表明该方法能够真实表达水库的复杂地形,且通过BIM平台能够计算不同水位下的库容,具有较高的测量精度和实用性。研究成果为水库管理、运营和维护提供了可靠的技术支持和科学依据,推动了库容测量技术的创新与应用。展开更多
Critical to the safe, efficient, and reliable operation of an autonomous maritime vessel is its ability to perceive the external environment through onboard sensors. For this research, data was collected from a LiDAR ...Critical to the safe, efficient, and reliable operation of an autonomous maritime vessel is its ability to perceive the external environment through onboard sensors. For this research, data was collected from a LiDAR sensor installed on a 16-foot catamaran unmanned vessel. This sensor generated point clouds of the surrounding maritime environment, which were then labeled by hand for training a machine learning (ML) model to perform a semantic segmentation task on LiDAR scans. In particular, the developed semantic segmentation classifies each point-cloud point as belonging to a certain buoy type. This paper describes the developed Unity Game Engine (Unity) simulation to emulate the maritime environment perceived by LiDAR with the goal of generating large (automatically labeled) simulation datasets and improving the ML model performance since hand-labeled real-life LiDAR scan data may be scarce. The Unity simulation data combined with labeled real-life point cloud data was used for a PointNet-based neural network model, the architecture of which is presented in this paper. Fitting the PointNet-based model on the simulation data followed by fine-tuning the combined dataset allowed for accurate semantic segmentation of point clouds on the real-world data. The ML model performance on several combinations of simulation and real-life data is explored. The resulting Intersection over Union (IoU) metric scores are quite high, ranging between 0.78 and 0.89, when validated on simulation and real-life data. The confusion matrix-entry values indicate an accurate semantic segmentation of the buoy types.展开更多
The process of disposing of expanded polystyrene (EPS) is by burning it in municipal incinerators. This process gives off EPS microplastics, which can find their way into water, food, blood, and major organ systems. Z...The process of disposing of expanded polystyrene (EPS) is by burning it in municipal incinerators. This process gives off EPS microplastics, which can find their way into water, food, blood, and major organ systems. Zophobas morio larvae are capable of consuming and breaking down EPS within their digestive tracts by minimizing the spread of microplastics. Studies of the consumption of EPS by Z. morio larvae are typically conducted under white or no visible light treatments. This study tested whether the color of visible light influenced the consumption rate of EPS by Z. morio larvae. If Z. morio larvae consume EPS under visible light, then visible light will influence the amount of EPS consumed. If results suggest that the consumption rate is influenced by visible light colors, then Z. morio larvae could be a solution for recycling EPS. This study’s procedure placed Z. morio larvae into 25 jars under one of six visible light treatments of red, yellow, green, blue, white, and no visible light. Each jar contained a pre-weighed block of EPS and six Z. morio larvae. After two weeks, the Z. morio larvae were removed from the jars, and the difference between each pre-weighed EPS block and the weight of the same partially consumed block was recorded in three trials. The data indicates that green and blue visible light treatments resulted in the greatest amount of EPS consumed by Z. morio larvae while the red and yellow had the least amount of EPS consumed by the Z. morio larvae. In conclusion, results indicate that green and blue visible light, compared to the no visible light treatment, could be used to influence the Z. morio larvae to consume more EPS. Green and blue visible light and Z. morio larvae could make the recycling process of EPS more environmentally friendly when used in households or by local environmental organizations.展开更多
金沙江下游水库具有地形陡峭、植被茂密等特点。针对库岸传统测量方式作业难度大、风险源多、效率低下;航空摄影测量受天气影响大、植被覆盖区域无法获取地面信息等难题,提出应用机载LiDAR获取库岸三维地形信息的方案。机载LiDAR具有非...金沙江下游水库具有地形陡峭、植被茂密等特点。针对库岸传统测量方式作业难度大、风险源多、效率低下;航空摄影测量受天气影响大、植被覆盖区域无法获取地面信息等难题,提出应用机载LiDAR获取库岸三维地形信息的方案。机载LiDAR具有非接触性测量、全天候作业、较强的植被穿透性等优点,可以很好解决以往库岸地形测绘方式的不足。通过检验点定量分析高程较差表明:总体中误差为±0.12 m,不同地物属性的中误差平均值为±0.12 m,点云精度满足相关测量规范要求,适用于金沙江下游大比例尺库岸地形测绘项目。The reservoir in the lower reaches of Jinsha River is characterized by steep terrain and dense vegetation. The traditional measurement method of reservoir bank is difficult to operate, and has many risk sources and low efficiency. Aerial photogrammetry suffers from weather impacts and inability to acquire ground information in areas with heavy vegetation cover. To address these issues, a proposal has been made to use airborne LiDAR for acquiring three-dimensional terrain information of the reservoir bank. Airborne LiDAR has the advantages of non-contact measurement, all-weather operation, strong vegetation penetration, etc., which can solve the shortcomings of the previous methods for topographic mapping of reservoir bank. Through the quantitative analysis of the elevation difference of the test points, it is shown that the overall median error is ±0.12 m, and the average median error of different ground features is ±0.12 m. The accuracy of the point cloud meets the requirements of the relevant measurement standards, and is suitable for the Large-scale topographic mapping project of the reservoir bank in the lower reaches of the Jinsha River.展开更多
基金supported by the NSFC (42374204, 42004143,42364012)the Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences (Grant No.YSBR-018)+3 种基金the Scientific Projects of Hainan Province(KJRC2023C05, ZDYF2021GXJS040)the Innovational Fund for Scientific and Technological Personnel of Hainan Provincethe Chinese Meridian ProjectPandeng Program of National Space Science Center,Chinese Academy of Sciences
文摘Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.
文摘研究旨在探讨库容测量中的新技术应用,提出了一种基于机载LiDAR(Light Detection and Ranging)系统和无人船单波束测深系统联合技术的测量框架。通过建筑信息模型(Building Information Modeling,BIM),将水库陆上与水下地形数据进行融合构建水库地形模型,实现精确的库容测量。以安徽省某水库为例,实验结果表明该方法能够真实表达水库的复杂地形,且通过BIM平台能够计算不同水位下的库容,具有较高的测量精度和实用性。研究成果为水库管理、运营和维护提供了可靠的技术支持和科学依据,推动了库容测量技术的创新与应用。
文摘Critical to the safe, efficient, and reliable operation of an autonomous maritime vessel is its ability to perceive the external environment through onboard sensors. For this research, data was collected from a LiDAR sensor installed on a 16-foot catamaran unmanned vessel. This sensor generated point clouds of the surrounding maritime environment, which were then labeled by hand for training a machine learning (ML) model to perform a semantic segmentation task on LiDAR scans. In particular, the developed semantic segmentation classifies each point-cloud point as belonging to a certain buoy type. This paper describes the developed Unity Game Engine (Unity) simulation to emulate the maritime environment perceived by LiDAR with the goal of generating large (automatically labeled) simulation datasets and improving the ML model performance since hand-labeled real-life LiDAR scan data may be scarce. The Unity simulation data combined with labeled real-life point cloud data was used for a PointNet-based neural network model, the architecture of which is presented in this paper. Fitting the PointNet-based model on the simulation data followed by fine-tuning the combined dataset allowed for accurate semantic segmentation of point clouds on the real-world data. The ML model performance on several combinations of simulation and real-life data is explored. The resulting Intersection over Union (IoU) metric scores are quite high, ranging between 0.78 and 0.89, when validated on simulation and real-life data. The confusion matrix-entry values indicate an accurate semantic segmentation of the buoy types.
文摘The process of disposing of expanded polystyrene (EPS) is by burning it in municipal incinerators. This process gives off EPS microplastics, which can find their way into water, food, blood, and major organ systems. Zophobas morio larvae are capable of consuming and breaking down EPS within their digestive tracts by minimizing the spread of microplastics. Studies of the consumption of EPS by Z. morio larvae are typically conducted under white or no visible light treatments. This study tested whether the color of visible light influenced the consumption rate of EPS by Z. morio larvae. If Z. morio larvae consume EPS under visible light, then visible light will influence the amount of EPS consumed. If results suggest that the consumption rate is influenced by visible light colors, then Z. morio larvae could be a solution for recycling EPS. This study’s procedure placed Z. morio larvae into 25 jars under one of six visible light treatments of red, yellow, green, blue, white, and no visible light. Each jar contained a pre-weighed block of EPS and six Z. morio larvae. After two weeks, the Z. morio larvae were removed from the jars, and the difference between each pre-weighed EPS block and the weight of the same partially consumed block was recorded in three trials. The data indicates that green and blue visible light treatments resulted in the greatest amount of EPS consumed by Z. morio larvae while the red and yellow had the least amount of EPS consumed by the Z. morio larvae. In conclusion, results indicate that green and blue visible light, compared to the no visible light treatment, could be used to influence the Z. morio larvae to consume more EPS. Green and blue visible light and Z. morio larvae could make the recycling process of EPS more environmentally friendly when used in households or by local environmental organizations.
文摘金沙江下游水库具有地形陡峭、植被茂密等特点。针对库岸传统测量方式作业难度大、风险源多、效率低下;航空摄影测量受天气影响大、植被覆盖区域无法获取地面信息等难题,提出应用机载LiDAR获取库岸三维地形信息的方案。机载LiDAR具有非接触性测量、全天候作业、较强的植被穿透性等优点,可以很好解决以往库岸地形测绘方式的不足。通过检验点定量分析高程较差表明:总体中误差为±0.12 m,不同地物属性的中误差平均值为±0.12 m,点云精度满足相关测量规范要求,适用于金沙江下游大比例尺库岸地形测绘项目。The reservoir in the lower reaches of Jinsha River is characterized by steep terrain and dense vegetation. The traditional measurement method of reservoir bank is difficult to operate, and has many risk sources and low efficiency. Aerial photogrammetry suffers from weather impacts and inability to acquire ground information in areas with heavy vegetation cover. To address these issues, a proposal has been made to use airborne LiDAR for acquiring three-dimensional terrain information of the reservoir bank. Airborne LiDAR has the advantages of non-contact measurement, all-weather operation, strong vegetation penetration, etc., which can solve the shortcomings of the previous methods for topographic mapping of reservoir bank. Through the quantitative analysis of the elevation difference of the test points, it is shown that the overall median error is ±0.12 m, and the average median error of different ground features is ±0.12 m. The accuracy of the point cloud meets the requirements of the relevant measurement standards, and is suitable for the Large-scale topographic mapping project of the reservoir bank in the lower reaches of the Jinsha River.
