Reliable and prompt information on forest above-ground biomass(AGB)and tree diameter at breast height(DBH)are crucial for sustainable forest management.Remote sensing technology,especially the Light Detection and Rang...Reliable and prompt information on forest above-ground biomass(AGB)and tree diameter at breast height(DBH)are crucial for sustainable forest management.Remote sensing technology,especially the Light Detection and Ranging(LiDAR)technology,has been proven to estimate important tree variables effectively.This study proposes predicting DBH and AGB from tree height and other LiDAR data extracted metrics.In the suggested DBH prediction,we developed a nonlinear estimation equation using the total tree height.As for the AGB prediction approach,we used regression methods such as multiple linear regression(MLR),random forest(RF)and support vector machine for regression(SVR).We conducted the study for the Gudao forest area dominated by Robinia Pseudoacacia trees,located in the Yellow River Delta(YRD),China.For our developed approaches,we used Unmanned Aerial Vehicle(UAV)and Backpack LiDAR point cloud datasets obtained in June 2017,and three field data measurements gathered in June 2017 and 2019 and October 2019,all from the same study area.The results demonstrate that:①The LiDAR data individual tree segmentation(ITS)from which we extracted individual tree information like tree location and tree height,was carried out with an overall accuracy F=0.91;②We used the ITS height data from the field stand in 2019 as a fit and developed a nonlinear DBH estimation equation with Root Mean Square Error(RMSE)=3.61 cm,later validated by the 2017 dataset;③Forest AGB at stand level was estimated with the MLR,RF and also SVR regression methods,and results show that the SVR method gave higher accuracy with R2=0.82 compared to the R2=0.72 of RF and the R2=0.70 of the MLR.Calculated AGB at plot level using the 2017 LiDAR data was used to validate both models’accuracy.Combining the UAV LiDAR data and the Backpack LiDAR significantly improved the overall ITS.The UAV LiDAR ability to provide high accuracy tree height abstraction,the DBH of the regression equation and other extracted LiDAR metrics showed high accuracy in estimating the forest AGB.This study shows that being cost-free is not the only advantage of free available software.In the performance of ITS and the LiDAR,metrics extraction proved to be as good as the commercially available software.展开更多
Background: Despite the physical and chemical effort to control Aedes aegypti, the arboviruses transmission in the south of Mexico remains latent. Trying to improve the methods of entomological surveillance routinely ...Background: Despite the physical and chemical effort to control Aedes aegypti, the arboviruses transmission in the south of Mexico remains latent. Trying to improve the methods of entomological surveillance routinely used, whether the estimation of resistance to insecticides used for its control, as well as their enzyme mechanisms, were influenced by the phase in which the mosquitoes were collected through three different collection methods was investigated. Materials and Methods: Mosquito collections from the “5 de Febrero” neighborhood in Tapachula, Mexico were obtained by ovitraps, larvitraps, and a CDC backpack aspirator. Insecticide resistance of F<sub>1</sub> females was determined by WHO diagnostic doses and resistance ratios (RR<sub>50</sub>), furthermore, levels of insecticide metabolism enzymes were determined by biochemical assays. Results: Overall, in mosquitoes collected by ovitraps, larvitraps, and CDC backpack aspirator respectively, the low mortalities obtained with the discriminant dose to Malathion (27.57%, 26.97%, and 26.91%), and to Bendiocarb (50.5%, 45.36%, and 54.97%) suggest resistance. However, LC<sub>50</sub> for Malathion (0.922, 0.934, and 0.915) and for Bendiocarb (0.112, 0.109, and 0.107);and the low resistance ratios (RR<sub>50</sub>) for Malathion (3.34, 3.29, and 3.27) and for Bendiocarb (2.15, 2.1, and 2.06) does not suggest resistance. Although a slight numerical variation is observed between the three LC<sub>50</sub> values, the overlap observed between their confidence intervals allows us to assume that there were no differences between the three methods. In general, esterases (determined with three substrates), glutathion S-transferases (GST) and cytochromes P<sup>450</sup> were statistically higher than those of the susceptible strain;and the three enzyme levels were statistically different among the three collection methods (P Conclusion: Although using a CDC backpack aspirator demonstrated being the best collection method determining a specific resistance mechanism (as elevation at the enzyme level) in the mosquito adult phase, any collection method is reliable to determine whether a field mosquito population is resistant or susceptible to an insecticide.展开更多
The evaluation of engineering rock mass quality is fundamental work for the engineering activities of rock mass.The increasing scale of rock mass engineering necessitates higher intelligence,timeliness,and accuracy in...The evaluation of engineering rock mass quality is fundamental work for the engineering activities of rock mass.The increasing scale of rock mass engineering necessitates higher intelligence,timeliness,and accuracy in engineering rock mass quality evaluation.As the core aspects of engineering rock mass quality evaluation,the structural characteristics,mechanical characteristics,and quality classification of rock mass have been innovated in recent years.The non-contact measurement technology for rock mass structure and rapid interpretation of rock mass structure information enables the intelligent extraction and analysis of rock mass structure parameters.The modular backpack laboratory system of rock mechanics provides an effective means to acquire rock mechanical parameters on-site conveniently.The theory of statistical mechanics of rock mass(SMRM)integrates various factors such as the rock mass properties,geological environment,and engineering disturbance,providing a theoretical basis for accurately evaluating the weakening and anisotropy of rock mass.The cloud computing platform established based on SMRM can provide technical support for the rapid calculation of rock mass parameters and instant evaluation of the rock mass quality.The development of intelligent evaluation method and technology is altering the conventional technical state of qualitative and semi-quantitative evaluation of engineering rock mass quality,supporting the realization of rock mass engineering construction with intellectualization and informatization.展开更多
The increasing necessity of load-carrying activities has led to greater human musculoskeletal damage and an increased metabolic cost.With the rise of exoskeleton technology,researchers have begun exploring different a...The increasing necessity of load-carrying activities has led to greater human musculoskeletal damage and an increased metabolic cost.With the rise of exoskeleton technology,researchers have begun exploring different approaches to developing wearable robots to augment human load-carrying ability.However,there is a lack of systematic discussion on biomechanics,mechanical designs,and augmentation performance.To achieve this,extensive studies have been reviewed and 108 references are selected mainly from 2013 to 2022 to address the most recent development.Other earlier 20 studies are selected to present the origin of different design principles.In terms of the way to achieve load-carrying augmentation,the exoskeletons reviewed in this paper are sorted by four categories based on the design principles,namely load-suspended backpacks,lower-limb exoskeletons providing joint torques,exoskeletons transferring load to the ground and exoskeletons transferring load between body segments.Specifically,the driving modes of active and passive,the structure of rigid and flexible,the conflict between assistive performance and the mass penalty of the exoskeleton,and the autonomy are discussed in detail in each section to illustrate the advances,challenges,and future trends of exoskeletons designed to carry loads.展开更多
This paper presents a practice-based research to achieve a deeper understanding of the spatial issues related to backpacker tourism, a booming industry in Budapest. The authors designed six backpacker hostels between ...This paper presents a practice-based research to achieve a deeper understanding of the spatial issues related to backpacker tourism, a booming industry in Budapest. The authors designed six backpacker hostels between 2013 and 2015, and of these, four are presently in operation. Hostels are the main infrastructures within the global network of backpacker tourism. Results from the design process revealed that the creation and operation of hostels are significantly influenced by three issues, namely, informality, density, and adaptability. These issues are negotiated on three interconnected tevels： the city, the building, and the interior. The authors developed an experimental structure for dormitory spaces as a conscious reaction to these issues. This experimental structure is presented and evaluated, and further paths of development are formulated based on the results.展开更多
University stores are central to campus life.They usually sell everything a student might need for class or dorm room.Living on the Tsinghua University campus, I enjoy shopping at the university stores. Past shopping ...University stores are central to campus life.They usually sell everything a student might need for class or dorm room.Living on the Tsinghua University campus, I enjoy shopping at the university stores. Past shopping excursions have added university logo jackets, hoodies and stylish backpacks to my wardrobe. I usually also grab necessities at the same time.展开更多
Purpose-The purpose of this paper is to explore the experience of the weight of a backpack as represented in typical Chinese children’s songs through a kind of phenomenological approach.Design/Approach/Methods-The co...Purpose-The purpose of this paper is to explore the experience of the weight of a backpack as represented in typical Chinese children’s songs through a kind of phenomenological approach.Design/Approach/Methods-The core issue pertaining to Chinese children’s songs about backpacks is how the weight sense of backpacks is generated and developed in the field of song phenomenology.Findings-The“whatness”of a backpack in typical songs has varied over the past six decades,meanwhile,the backpack and its songs conceal not only the secrets of childhood but also those of China’s educational system.Originality/Value-The originality of this paper embodies the unique perspective to provide a new insight into the current scholarship of the micro-politics of song-singing and the weight sense of backpack.展开更多
文摘Reliable and prompt information on forest above-ground biomass(AGB)and tree diameter at breast height(DBH)are crucial for sustainable forest management.Remote sensing technology,especially the Light Detection and Ranging(LiDAR)technology,has been proven to estimate important tree variables effectively.This study proposes predicting DBH and AGB from tree height and other LiDAR data extracted metrics.In the suggested DBH prediction,we developed a nonlinear estimation equation using the total tree height.As for the AGB prediction approach,we used regression methods such as multiple linear regression(MLR),random forest(RF)and support vector machine for regression(SVR).We conducted the study for the Gudao forest area dominated by Robinia Pseudoacacia trees,located in the Yellow River Delta(YRD),China.For our developed approaches,we used Unmanned Aerial Vehicle(UAV)and Backpack LiDAR point cloud datasets obtained in June 2017,and three field data measurements gathered in June 2017 and 2019 and October 2019,all from the same study area.The results demonstrate that:①The LiDAR data individual tree segmentation(ITS)from which we extracted individual tree information like tree location and tree height,was carried out with an overall accuracy F=0.91;②We used the ITS height data from the field stand in 2019 as a fit and developed a nonlinear DBH estimation equation with Root Mean Square Error(RMSE)=3.61 cm,later validated by the 2017 dataset;③Forest AGB at stand level was estimated with the MLR,RF and also SVR regression methods,and results show that the SVR method gave higher accuracy with R2=0.82 compared to the R2=0.72 of RF and the R2=0.70 of the MLR.Calculated AGB at plot level using the 2017 LiDAR data was used to validate both models’accuracy.Combining the UAV LiDAR data and the Backpack LiDAR significantly improved the overall ITS.The UAV LiDAR ability to provide high accuracy tree height abstraction,the DBH of the regression equation and other extracted LiDAR metrics showed high accuracy in estimating the forest AGB.This study shows that being cost-free is not the only advantage of free available software.In the performance of ITS and the LiDAR,metrics extraction proved to be as good as the commercially available software.
文摘Background: Despite the physical and chemical effort to control Aedes aegypti, the arboviruses transmission in the south of Mexico remains latent. Trying to improve the methods of entomological surveillance routinely used, whether the estimation of resistance to insecticides used for its control, as well as their enzyme mechanisms, were influenced by the phase in which the mosquitoes were collected through three different collection methods was investigated. Materials and Methods: Mosquito collections from the “5 de Febrero” neighborhood in Tapachula, Mexico were obtained by ovitraps, larvitraps, and a CDC backpack aspirator. Insecticide resistance of F<sub>1</sub> females was determined by WHO diagnostic doses and resistance ratios (RR<sub>50</sub>), furthermore, levels of insecticide metabolism enzymes were determined by biochemical assays. Results: Overall, in mosquitoes collected by ovitraps, larvitraps, and CDC backpack aspirator respectively, the low mortalities obtained with the discriminant dose to Malathion (27.57%, 26.97%, and 26.91%), and to Bendiocarb (50.5%, 45.36%, and 54.97%) suggest resistance. However, LC<sub>50</sub> for Malathion (0.922, 0.934, and 0.915) and for Bendiocarb (0.112, 0.109, and 0.107);and the low resistance ratios (RR<sub>50</sub>) for Malathion (3.34, 3.29, and 3.27) and for Bendiocarb (2.15, 2.1, and 2.06) does not suggest resistance. Although a slight numerical variation is observed between the three LC<sub>50</sub> values, the overlap observed between their confidence intervals allows us to assume that there were no differences between the three methods. In general, esterases (determined with three substrates), glutathion S-transferases (GST) and cytochromes P<sup>450</sup> were statistically higher than those of the susceptible strain;and the three enzyme levels were statistically different among the three collection methods (P Conclusion: Although using a CDC backpack aspirator demonstrated being the best collection method determining a specific resistance mechanism (as elevation at the enzyme level) in the mosquito adult phase, any collection method is reliable to determine whether a field mosquito population is resistant or susceptible to an insecticide.
基金the National Natural Science Foundation of China(Grant Nos.41831290 and 42177142)the Key R&D Project from Zhejiang Province,China(Grant No.2020C03092)the Key Research and Development Program of Shaanxi(Grant No.2023-YBSF-486).
文摘The evaluation of engineering rock mass quality is fundamental work for the engineering activities of rock mass.The increasing scale of rock mass engineering necessitates higher intelligence,timeliness,and accuracy in engineering rock mass quality evaluation.As the core aspects of engineering rock mass quality evaluation,the structural characteristics,mechanical characteristics,and quality classification of rock mass have been innovated in recent years.The non-contact measurement technology for rock mass structure and rapid interpretation of rock mass structure information enables the intelligent extraction and analysis of rock mass structure parameters.The modular backpack laboratory system of rock mechanics provides an effective means to acquire rock mechanical parameters on-site conveniently.The theory of statistical mechanics of rock mass(SMRM)integrates various factors such as the rock mass properties,geological environment,and engineering disturbance,providing a theoretical basis for accurately evaluating the weakening and anisotropy of rock mass.The cloud computing platform established based on SMRM can provide technical support for the rapid calculation of rock mass parameters and instant evaluation of the rock mass quality.The development of intelligent evaluation method and technology is altering the conventional technical state of qualitative and semi-quantitative evaluation of engineering rock mass quality,supporting the realization of rock mass engineering construction with intellectualization and informatization.
基金supported by the National Key R&D Program of China(Grant No.2020YFC2007800)the National Natural Science Foundation of China(Grant Nos.52005191 and 52027806)。
文摘The increasing necessity of load-carrying activities has led to greater human musculoskeletal damage and an increased metabolic cost.With the rise of exoskeleton technology,researchers have begun exploring different approaches to developing wearable robots to augment human load-carrying ability.However,there is a lack of systematic discussion on biomechanics,mechanical designs,and augmentation performance.To achieve this,extensive studies have been reviewed and 108 references are selected mainly from 2013 to 2022 to address the most recent development.Other earlier 20 studies are selected to present the origin of different design principles.In terms of the way to achieve load-carrying augmentation,the exoskeletons reviewed in this paper are sorted by four categories based on the design principles,namely load-suspended backpacks,lower-limb exoskeletons providing joint torques,exoskeletons transferring load to the ground and exoskeletons transferring load between body segments.Specifically,the driving modes of active and passive,the structure of rigid and flexible,the conflict between assistive performance and the mass penalty of the exoskeleton,and the autonomy are discussed in detail in each section to illustrate the advances,challenges,and future trends of exoskeletons designed to carry loads.
文摘This paper presents a practice-based research to achieve a deeper understanding of the spatial issues related to backpacker tourism, a booming industry in Budapest. The authors designed six backpacker hostels between 2013 and 2015, and of these, four are presently in operation. Hostels are the main infrastructures within the global network of backpacker tourism. Results from the design process revealed that the creation and operation of hostels are significantly influenced by three issues, namely, informality, density, and adaptability. These issues are negotiated on three interconnected tevels： the city, the building, and the interior. The authors developed an experimental structure for dormitory spaces as a conscious reaction to these issues. This experimental structure is presented and evaluated, and further paths of development are formulated based on the results.
文摘University stores are central to campus life.They usually sell everything a student might need for class or dorm room.Living on the Tsinghua University campus, I enjoy shopping at the university stores. Past shopping excursions have added university logo jackets, hoodies and stylish backpacks to my wardrobe. I usually also grab necessities at the same time.
文摘Purpose-The purpose of this paper is to explore the experience of the weight of a backpack as represented in typical Chinese children’s songs through a kind of phenomenological approach.Design/Approach/Methods-The core issue pertaining to Chinese children’s songs about backpacks is how the weight sense of backpacks is generated and developed in the field of song phenomenology.Findings-The“whatness”of a backpack in typical songs has varied over the past six decades,meanwhile,the backpack and its songs conceal not only the secrets of childhood but also those of China’s educational system.Originality/Value-The originality of this paper embodies the unique perspective to provide a new insight into the current scholarship of the micro-politics of song-singing and the weight sense of backpack.
