The increasing global population at a rapid pace makes road trafficdense;managing such massive traffic is challenging. In developing countrieslike Pakistan, road traffic accidents (RTA) have the highest mortality perc...The increasing global population at a rapid pace makes road trafficdense;managing such massive traffic is challenging. In developing countrieslike Pakistan, road traffic accidents (RTA) have the highest mortality percentageamong other Asian countries. The main reasons for RTAs are roadcracks and potholes. Understanding the need for an automated system forthe detection of cracks and potholes, this study proposes a decision supportsystem (DSS) for an autonomous road information system for smart citydevelopment with the use of deep learning. The proposed DSS works in layerswhere initially the image of roads is captured and coordinates attached to theimage with the help of global positioning system (GPS), communicated tothe decision layer to find about the cracks and potholes in the roads, andeventually, that information is passed to the road management informationsystem, which gives information to drivers and the maintenance department.For the decision layer, we projected a CNN-based model for pothole crackdetection (PCD). Aimed at training, a K-fold cross-validation strategy wasused where the value of K was set to 10. The training of PCD was completedwith a self-collected dataset consisting of 6000 images from Pakistani roads.The proposed PCD achieved 98% of precision, 97% recall, and accuracy whiletesting on unseen images. The results produced by our model are higher thanthe existing model in terms of performance and computational cost, whichproves its significance.展开更多
The goal of this study is to provide information on the process of pothole growth on a gorge streambed.Pothole geometries were measured in a reach of the Dabu river bed at the head of a gorge more than 200 m deeply in...The goal of this study is to provide information on the process of pothole growth on a gorge streambed.Pothole geometries were measured in a reach of the Dabu river bed at the head of a gorge more than 200 m deeply incising into a 650-750 m high planation surface formed in the middle Miocene in northern Guangdong,China.Geometric and derivative data of the potholes obtained from fieldwork were interpreted using standard statistical methodologies.Our study shows that the formation and development of a stream pothole were only related to local conditions of a stream reach where the pothole occurs;the weaknesses,which are usually intersect fractures,typically interconnected vertical joints,or triangular pits generated by hitting of rock fragments during floods,initiate the pothole development on a streambed;the geometrical dimensions of the potholes are controlled by tectonic joints developed in bedrock of the stream reach;the radius and the depth of potholes are strongly(log) positive correlated;the pothole shapes and the flow patterns are inconstant during pothole growth;a pothole can be formed within a short period,but cannot be fully developed and maintained for a long time in a strong incision streambed.The finding in our study can improve the understanding of Quaternary environment in Guangdong.展开更多
Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, r...Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, respectively, the depth and mean diameter of pothole, M is a critical size of the initial concavities （seminal potholes） that subsequently underwent growth, and N is the ratio of diameter expanding （wall erosion） speed to deepening （floor abrasion） speed. For the stream potholes, N is generally less than 1 with an average value of 0.67, M varies from 5.3 cm to 40.5 cm with an average of 20 cm, and N decreases gently with increasing M. However, the marine and hillside potholes are generally characterized by N 〉 1 and M 〈 10-14 cm, and a power-law relationship N 4.24M o.78 （coefficient of determination R2 0.75, M is in cm） exists. The results indicate that depth increases faster than diameter for stream potholes due to the larger size of grinding stones （〉5-10 cm）, while depth increases slower than diameter for marine potholes and hillside potholes due to the smaller size of grinding stones （〈5-10 cm）. The pothole h-D relationship is nearly independent of rock type. Knowledge of the pothole depth-diameter relationship is useful in a number of contexts, including simulation of hydraulic dynamics, theoretical considerations of erosion, comprehension of channel incision and development of canyons and gorges, and accurate estimation of excavation volume and mechanical strength ofpotholed bedrock in the design and stability analysis of hydraulic and environmental engineering projects （e.g. dam construction and river dredging）.展开更多
Road potholes can cause serious social issues,such as unexpected damages to vehicles and traffic accidents.For efficient road management,technologies that quickly find potholes are required,and thus researches on such...Road potholes can cause serious social issues,such as unexpected damages to vehicles and traffic accidents.For efficient road management,technologies that quickly find potholes are required,and thus researches on such technologies have been conducted actively.The three-dimensional(3D)reconstruction method has relatively high accuracy and can be used in practice but it has limited application owing to its long data processing time and high sensor maintenance cost.The two-dimensional(2D)vision method has the advantage of inexpensive and easy application of sensor.Recently,although the 2D vision method using the convolutional neural network(CNN)has shown improved pothole detection performance and adaptability,large amount of data is required to sufficiently train the CNN.Therefore,we propose a method to improve the learning performance of CNN-based object detection model by artificially generating synthetic data similar to a pothole and enhancing the learning data.Additionally,to make the defective areas appear more contrasting,the transformed disparity map(TDM)was calculated using stereo-vision cameras,and the detection performance of the model was further improved through the late fusion with RGB(Red,Green,Blue)images.Consequently,through the convergence of multimodal You Only Look Once(YOLO)frameworks trained by RGB images and TDMs respectively,the detection performance was enhanced by 10.7%compared with that when using only RGB.Further,the superiority of the proposed method was confirmed by showing that the data processing speed was two times faster than the existing 3D reconstruction method.展开更多
Since the year 2000, the city of Gweru has had an unprecedented proliferation of unattended potholes on most of its roads. These potholes have caused discomfort to the motoring public, caused death to others and damag...Since the year 2000, the city of Gweru has had an unprecedented proliferation of unattended potholes on most of its roads. These potholes have caused discomfort to the motoring public, caused death to others and damaged vehicles. This paper presents the results of a study that sought to establish the spatial distribution of potholes and determine their socio-economic impacts in Gweru＇s residential areas. Pothole location and dimensions were measured in the field whilst interviews and questionnaires were administered to vehicle owners, motor mechanic experts, drivers and the travelling public to determine their socio-economic and mechanical impacts. Stratified, convenience and purposive sampling methods were used in the selection of study streets and respondents to questionnaires and interviews. Results revealed that potholes are more concentrated in high density residential areas compared to low density areas. This is primarily due to the substandard construction of roads done in high density residential areas. Other causes of pothole formation identified during this study are poor drainage on the roads, rainfall impact, advanced age of roads, poor or lack of maintenance, type and volume of traffic as well as the effect of tree-root prying on paved surfaces. It is recommended that Gweru City Council enters into partnerships in road construction. The city should also establish fundraising projects to augment its budget. This would help ease problems of service delivery including road maintenance. Signposts can be erected to warn drivers about these hazards in the most affected streets and suburbs. It is also important that council set aside a toll-free telephone line link with road users so that areas where new potholes have been detected are quickly reported and attended to. This will not only save lives but also reduce road maintenance costs and vehicle damage.展开更多
The potholes are perceptible erosional features associated with bedrock channels. They play an essential role in bedrock incision studies, but little work has been published on the development of potholes, especially ...The potholes are perceptible erosional features associated with bedrock channels. They play an essential role in bedrock incision studies, but little work has been published on the development of potholes, especially in Bedrock Rivers in India. The present site-specific study aims to analyze the role of physical properties of bedrock and associated structures in the process of development of potholes and to classify the potholes based on their dimensions. The Khari River gorge formed over Mesozoic Sandstone with six bedrock terraces exposed along a confined segment of the river. The site is manifested by strath terraces, grooves, potholes, and knick points. Three stretches of Khari Gorge have been studied in detail for this purpose. The pothole dimensions, joint orientations, rock mass strength, physical properties of rock, and placing of potholes to present active channels were measured. The analysis shows the inverse relationship between the size of pothole and rock properties. The distance of potholes and active channels govern the essential factor and manifest the role of flow hydraulics. The high density of matured potholes near active channels over immature potholes supports primary control of hydraulics of flow over rock properties.展开更多
Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniqu...Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniques,especially deep learningmodels,developed to tackle these problems.This article first introduces the sensing systems employed for 2-D and 3-D road data acquisition,including camera(s),laser scanners and Microsoft Kinect.It then comprehensively reviews the SoTA computer vision algorithms,including(1)classical 2-D image processing,(2)3-D point cloud modelling and segmentation and(3)machine/deep learning,developed for road pothole detection.The article also discusses the existing challenges and future development trends of computer vision-based road pothole detection approaches:classical 2-D image processing-based and 3-D point cloud modelling and segmentation-based approaches have already become history;and convolutional neural networks(CNNs)have demonstrated compelling road pothole detection results and are promising to break the bottleneck with future advances in self/un-supervised learning for multi-modal semantic segmentation.We believe that this survey can serve as practical guidance for developing the next-generation road condition assessment systems.展开更多
To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavem...To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavement distresses. The survey shows that 30 m2 out of the entire 3.8 × 104 m2 pavement exhibits potholes and alligator cracks. Other surface cracks are also found, including regular longitudinal cracks, short hairline cracks, bubble cracks, and ring cracks. Rutting and shoving are not observed on the pavement. The causes of pavement distresses are discussed by analyzing the pavement mechanical response with actual traffic composition. Research results indicate that the regular longitudinal cracks occurring at ribs near wheelpaths are due to fatigue damage. Short hair cracking and bubble cracking are mainly related to construction defects. Alligator cracks are the results of the development of regular, short hair and bubble cracks lacking effective maintenance. Potholes are induced by the cracking and moisture ingression.展开更多
Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting （PSMT）, carpet seedling of mechanical transplanting （CSMT） and mechanical direct seeding （MDS） is of great...Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting （PSMT）, carpet seedling of mechanical transplanting （CSMT） and mechanical direct seeding （MDS） is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties ofjaponica-indica hybrid rice （JIHR）,japonica conventional rice （JCR） and indica hybrid rice （IHR）. Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that （i） the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of I HR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT; （ii） high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT; （iii） moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.展开更多
In vehicle dynamics, there are wide applications concerning the simulation of vehicles on roads. These simulation applications relate to vehicle driving, ride comfort and durability. An accurate prediction of simulati...In vehicle dynamics, there are wide applications concerning the simulation of vehicles on roads. These simulation applications relate to vehicle driving, ride comfort and durability. An accurate prediction of simulation results requires reliability and efficiency of road representations. The MATLAB graphical user interface module, called MATLAB GUI, is used to develop virtual simulation laboratories that allow the user to interact with a computer program using graphical objects. In this context, the aim of this article is to use the MATLAB OpenCRG suite of tools and the MATLAB GUI to develop a virtual environment for simulating a 3D road profile. A three-dimensional model of a pothole with variable parameters is developed and integrated into the 3D road profile.展开更多
The Soil and Water Assessment Tool(SWAT)is an ecohydrological watershed-scale model which was initially developed in the early 1990s to simulate the impacts of land use,management systems,and climate on hydrology and/...The Soil and Water Assessment Tool(SWAT)is an ecohydrological watershed-scale model which was initially developed in the early 1990s to simulate the impacts of land use,management systems,and climate on hydrology and/or water quality.First adopted in the U.S.,the use of the model then spread to Europe and then later to Asia and other regions.The range of applications that SWAT has been applied to have also expanded dramatically,which influenced ongoing model development which has been virtually continuous over the past two decades.A key component of many SWAT applications in Asia is accounting for rice paddy production that is common in some subregions within the continent.However,most of these studies do not provide explicit details of how rice production was simulated in SWAT.Other research has revealed that significant problems occur when trying to represent rice paddy systems in standard versions of SWAT,due to limitations in algorithms based on the runoff curve number approach or the pothole option.In response,key modifications have been made to SWAT in recent studies that have resulted in more accurate representation of rice paddy systems.These developments point to the need for the incorporation of an enhanced rice paddy module within SWAT to better capture rice paddy hydrological and pollutant dynamics,which would support improved use of the model in Asia and other rice production regions.Subtopics related to simulating rice production in SWAT are discussed as follows:1)an overview of global rice production;2)history of SWAT development;3)typical approaches for simulating rice production;4)problems associated with the typical approaches;5)recent code modifications to address deficiencies in replicating rice paddy systems;6)recommendations for developing a standard rice paddy module for future SWAT codes.展开更多
基金Hunan Provincial Science and Technology Innovation Leader Project,Grant/Award Number:2021RC4025National Natural ScienceFoundation of China,Grant/Award Number:51808209Hunan Provincial Innovation Foundation for Postgraduate,Grant/Award Number:QL20210106.
文摘The increasing global population at a rapid pace makes road trafficdense;managing such massive traffic is challenging. In developing countrieslike Pakistan, road traffic accidents (RTA) have the highest mortality percentageamong other Asian countries. The main reasons for RTAs are roadcracks and potholes. Understanding the need for an automated system forthe detection of cracks and potholes, this study proposes a decision supportsystem (DSS) for an autonomous road information system for smart citydevelopment with the use of deep learning. The proposed DSS works in layerswhere initially the image of roads is captured and coordinates attached to theimage with the help of global positioning system (GPS), communicated tothe decision layer to find about the cracks and potholes in the roads, andeventually, that information is passed to the road management informationsystem, which gives information to drivers and the maintenance department.For the decision layer, we projected a CNN-based model for pothole crackdetection (PCD). Aimed at training, a K-fold cross-validation strategy wasused where the value of K was set to 10. The training of PCD was completedwith a self-collected dataset consisting of 6000 images from Pakistani roads.The proposed PCD achieved 98% of precision, 97% recall, and accuracy whiletesting on unseen images. The results produced by our model are higher thanthe existing model in terms of performance and computational cost, whichproves its significance.
基金National Natural Science Foundation of China,No.40871020Guangdong Natural Science Foundation, No.7005836
文摘The goal of this study is to provide information on the process of pothole growth on a gorge streambed.Pothole geometries were measured in a reach of the Dabu river bed at the head of a gorge more than 200 m deeply incising into a 650-750 m high planation surface formed in the middle Miocene in northern Guangdong,China.Geometric and derivative data of the potholes obtained from fieldwork were interpreted using standard statistical methodologies.Our study shows that the formation and development of a stream pothole were only related to local conditions of a stream reach where the pothole occurs;the weaknesses,which are usually intersect fractures,typically interconnected vertical joints,or triangular pits generated by hitting of rock fragments during floods,initiate the pothole development on a streambed;the geometrical dimensions of the potholes are controlled by tectonic joints developed in bedrock of the stream reach;the radius and the depth of potholes are strongly(log) positive correlated;the pothole shapes and the flow patterns are inconstant during pothole growth;a pothole can be formed within a short period,but cannot be fully developed and maintained for a long time in a strong incision streambed.The finding in our study can improve the understanding of Quaternary environment in Guangdong.
基金Natural Sciences and Engineering Research Council of Canada for a discovery grant
文摘Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, respectively, the depth and mean diameter of pothole, M is a critical size of the initial concavities （seminal potholes） that subsequently underwent growth, and N is the ratio of diameter expanding （wall erosion） speed to deepening （floor abrasion） speed. For the stream potholes, N is generally less than 1 with an average value of 0.67, M varies from 5.3 cm to 40.5 cm with an average of 20 cm, and N decreases gently with increasing M. However, the marine and hillside potholes are generally characterized by N 〉 1 and M 〈 10-14 cm, and a power-law relationship N 4.24M o.78 （coefficient of determination R2 0.75, M is in cm） exists. The results indicate that depth increases faster than diameter for stream potholes due to the larger size of grinding stones （〉5-10 cm）, while depth increases slower than diameter for marine potholes and hillside potholes due to the smaller size of grinding stones （〈5-10 cm）. The pothole h-D relationship is nearly independent of rock type. Knowledge of the pothole depth-diameter relationship is useful in a number of contexts, including simulation of hydraulic dynamics, theoretical considerations of erosion, comprehension of channel incision and development of canyons and gorges, and accurate estimation of excavation volume and mechanical strength ofpotholed bedrock in the design and stability analysis of hydraulic and environmental engineering projects （e.g. dam construction and river dredging）.
基金This research was funded by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MOE)(No.2021R1I1A3055973)and the Soonchunhyang University Research Fund.
文摘Road potholes can cause serious social issues,such as unexpected damages to vehicles and traffic accidents.For efficient road management,technologies that quickly find potholes are required,and thus researches on such technologies have been conducted actively.The three-dimensional(3D)reconstruction method has relatively high accuracy and can be used in practice but it has limited application owing to its long data processing time and high sensor maintenance cost.The two-dimensional(2D)vision method has the advantage of inexpensive and easy application of sensor.Recently,although the 2D vision method using the convolutional neural network(CNN)has shown improved pothole detection performance and adaptability,large amount of data is required to sufficiently train the CNN.Therefore,we propose a method to improve the learning performance of CNN-based object detection model by artificially generating synthetic data similar to a pothole and enhancing the learning data.Additionally,to make the defective areas appear more contrasting,the transformed disparity map(TDM)was calculated using stereo-vision cameras,and the detection performance of the model was further improved through the late fusion with RGB(Red,Green,Blue)images.Consequently,through the convergence of multimodal You Only Look Once(YOLO)frameworks trained by RGB images and TDMs respectively,the detection performance was enhanced by 10.7%compared with that when using only RGB.Further,the superiority of the proposed method was confirmed by showing that the data processing speed was two times faster than the existing 3D reconstruction method.
文摘Since the year 2000, the city of Gweru has had an unprecedented proliferation of unattended potholes on most of its roads. These potholes have caused discomfort to the motoring public, caused death to others and damaged vehicles. This paper presents the results of a study that sought to establish the spatial distribution of potholes and determine their socio-economic impacts in Gweru＇s residential areas. Pothole location and dimensions were measured in the field whilst interviews and questionnaires were administered to vehicle owners, motor mechanic experts, drivers and the travelling public to determine their socio-economic and mechanical impacts. Stratified, convenience and purposive sampling methods were used in the selection of study streets and respondents to questionnaires and interviews. Results revealed that potholes are more concentrated in high density residential areas compared to low density areas. This is primarily due to the substandard construction of roads done in high density residential areas. Other causes of pothole formation identified during this study are poor drainage on the roads, rainfall impact, advanced age of roads, poor or lack of maintenance, type and volume of traffic as well as the effect of tree-root prying on paved surfaces. It is recommended that Gweru City Council enters into partnerships in road construction. The city should also establish fundraising projects to augment its budget. This would help ease problems of service delivery including road maintenance. Signposts can be erected to warn drivers about these hazards in the most affected streets and suburbs. It is also important that council set aside a toll-free telephone line link with road users so that areas where new potholes have been detected are quickly reported and attended to. This will not only save lives but also reduce road maintenance costs and vehicle damage.
文摘The potholes are perceptible erosional features associated with bedrock channels. They play an essential role in bedrock incision studies, but little work has been published on the development of potholes, especially in Bedrock Rivers in India. The present site-specific study aims to analyze the role of physical properties of bedrock and associated structures in the process of development of potholes and to classify the potholes based on their dimensions. The Khari River gorge formed over Mesozoic Sandstone with six bedrock terraces exposed along a confined segment of the river. The site is manifested by strath terraces, grooves, potholes, and knick points. Three stretches of Khari Gorge have been studied in detail for this purpose. The pothole dimensions, joint orientations, rock mass strength, physical properties of rock, and placing of potholes to present active channels were measured. The analysis shows the inverse relationship between the size of pothole and rock properties. The distance of potholes and active channels govern the essential factor and manifest the role of flow hydraulics. The high density of matured potholes near active channels over immature potholes supports primary control of hydraulics of flow over rock properties.
基金the National Key R&D Program of China(Grant No.2020AAA0108100)the Fundamental Research Funds for the Central Universities(Grant Nos.22120220184,22120220214 and 2022-5-YB-08)the Shanghai Municipal Science and Technology Major Project(Grant No.2021SHZDZX0100).
文摘Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniques,especially deep learningmodels,developed to tackle these problems.This article first introduces the sensing systems employed for 2-D and 3-D road data acquisition,including camera(s),laser scanners and Microsoft Kinect.It then comprehensively reviews the SoTA computer vision algorithms,including(1)classical 2-D image processing,(2)3-D point cloud modelling and segmentation and(3)machine/deep learning,developed for road pothole detection.The article also discusses the existing challenges and future development trends of computer vision-based road pothole detection approaches:classical 2-D image processing-based and 3-D point cloud modelling and segmentation-based approaches have already become history;and convolutional neural networks(CNNs)have demonstrated compelling road pothole detection results and are promising to break the bottleneck with future advances in self/un-supervised learning for multi-modal semantic segmentation.We believe that this survey can serve as practical guidance for developing the next-generation road condition assessment systems.
基金The National Key Technology R&D Program during the 11th Five-Year Plan Period(No.2009BAG15B03)
文摘To obtain a complete picture of the epoxy asphalt pavement condition on the Second Nanjing Yangtze River Bridge, an on-site survey is conducted to collect information regarding traffic composition and extents of pavement distresses. The survey shows that 30 m2 out of the entire 3.8 × 104 m2 pavement exhibits potholes and alligator cracks. Other surface cracks are also found, including regular longitudinal cracks, short hairline cracks, bubble cracks, and ring cracks. Rutting and shoving are not observed on the pavement. The causes of pavement distresses are discussed by analyzing the pavement mechanical response with actual traffic composition. Research results indicate that the regular longitudinal cracks occurring at ribs near wheelpaths are due to fatigue damage. Short hair cracking and bubble cracking are mainly related to construction defects. Alligator cracks are the results of the development of regular, short hair and bubble cracks lacking effective maintenance. Potholes are induced by the cracking and moisture ingression.
基金The Special Fund for Agro-scientific Research in the Public Interest(201303102)the Major Independent Innovation Project in Jiangsu Province,China(CX(15)1002)+3 种基金the National Key Research Program of China(2016YFD0300503)the Science and Technology Plan of Jiangsu Province,China(BE2015340)the Research Innovation Program for College Graduates of Jiangsu Province,China(KYLX15_1369)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China supported this study
文摘Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting （PSMT）, carpet seedling of mechanical transplanting （CSMT） and mechanical direct seeding （MDS） is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties ofjaponica-indica hybrid rice （JIHR）,japonica conventional rice （JCR） and indica hybrid rice （IHR）. Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that （i） the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of I HR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT; （ii） high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT; （iii） moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.
文摘In vehicle dynamics, there are wide applications concerning the simulation of vehicles on roads. These simulation applications relate to vehicle driving, ride comfort and durability. An accurate prediction of simulation results requires reliability and efficiency of road representations. The MATLAB graphical user interface module, called MATLAB GUI, is used to develop virtual simulation laboratories that allow the user to interact with a computer program using graphical objects. In this context, the aim of this article is to use the MATLAB OpenCRG suite of tools and the MATLAB GUI to develop a virtual environment for simulating a 3D road profile. A three-dimensional model of a pothole with variable parameters is developed and integrated into the 3D road profile.
基金The work was partially supported by the Rural Development Administration of the Republic of Korea(Grant No.M2100296).
文摘The Soil and Water Assessment Tool(SWAT)is an ecohydrological watershed-scale model which was initially developed in the early 1990s to simulate the impacts of land use,management systems,and climate on hydrology and/or water quality.First adopted in the U.S.,the use of the model then spread to Europe and then later to Asia and other regions.The range of applications that SWAT has been applied to have also expanded dramatically,which influenced ongoing model development which has been virtually continuous over the past two decades.A key component of many SWAT applications in Asia is accounting for rice paddy production that is common in some subregions within the continent.However,most of these studies do not provide explicit details of how rice production was simulated in SWAT.Other research has revealed that significant problems occur when trying to represent rice paddy systems in standard versions of SWAT,due to limitations in algorithms based on the runoff curve number approach or the pothole option.In response,key modifications have been made to SWAT in recent studies that have resulted in more accurate representation of rice paddy systems.These developments point to the need for the incorporation of an enhanced rice paddy module within SWAT to better capture rice paddy hydrological and pollutant dynamics,which would support improved use of the model in Asia and other rice production regions.Subtopics related to simulating rice production in SWAT are discussed as follows:1)an overview of global rice production;2)history of SWAT development;3)typical approaches for simulating rice production;4)problems associated with the typical approaches;5)recent code modifications to address deficiencies in replicating rice paddy systems;6)recommendations for developing a standard rice paddy module for future SWAT codes.
