The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects.These models necessit...The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects.These models necessitate defining breach geometry and formation time,for which various parametric models have been proposed.These models yield different values for average breach width,time of failure,and consequently,peak flows,as demonstrated by several researchers.This study analyzed the effect of selecting a breach parametric model on the hydraulic variables,potential damages,and hazard classification of structures.Three common parametric models were compared using a set of synthetic cases and a real off-stream reservoir.Results indicated significant effects of model choice.Material erodibility exerted a significant impact,surpassing that of failure mode.Other factors,such as the Manning coefficient,significantly affected the results.Utilizing an inadequate model or lacking information on dike material can lead to overly conservative or underestimated outcomes,thereby affecting hazard classification.展开更多
Since the 21st century, the world is facing increasingly severe disaster problems, which greatly affect the development of human economy. As one of the natural disasters, the study of marine geological disasters is be...Since the 21st century, the world is facing increasingly severe disaster problems, which greatly affect the development of human economy. As one of the natural disasters, the study of marine geological disasters is becoming a research hotspot. From the perspective of disaster mechanism, this paper reviews the classification methods of marine geological disasters from 1980 to now, and discusses the genetic mechanism of typical marine geological disasters on the continental margin, which provides scientific basis for the construction of marine engineering.展开更多
The primary aim of this study was to classify the hazard level of brown planthopper(BPH)damage in rice.Three datasets,including spectral reflectance corresponding to the sensitive wavelengths from rice canopy spectral...The primary aim of this study was to classify the hazard level of brown planthopper(BPH)damage in rice.Three datasets,including spectral reflectance corresponding to the sensitive wavelengths from rice canopy spectral wavelengths,rice stem spectral wavelengths,and fusion information of rice canopy and stem spectral wavelengths were used for BPH hazard level classification by using different algorithms.Datasets and algorithms were optimized by the BPH hazard level classification effects(which was evaluated by indices of accuracy,precision,recall,F_(1),and k-value).The optimized algorithm combination was used to build a hazard level classification model for spectral reflectance corresponding to the sensitive wavelength from the rice canopy spectral images.Results showed that:(1)The spectral reflectance corresponding to the sensitive wavelengths of fusion information dataset performed best in BPH hazard level classification,with the highest accuracy(99.08%),precision(99.31%),recall(98.83%),F_(1)(0.99),and k-value(0.99).(2)The optimum algorithm combination was Savitzky-Golay(S-G)smoothing,principal component analysis(PCA)for sensitive wavelength selection,and broad-learning system(BLS)for modeling.(3)The spectral reflectance corresponding to the sensitive wavelengths dataset of rice canopy spectral images achieved accuracy(80.63%),precision(80.28%),recall(77.03%),F_(1)(0.79),and k-value(0.74)in classifying BPH hazard level by using the optimum algorithm combination.展开更多
基金supported by the Spanish Ministry of Science,Innovation and Universities through the projects ACROPOLIS(Grant No.RTC2019-007343-5)and DOLMEN(Grant No.PID2021-122661OB-I00)the Spanish Ministry of Economy and Competitiveness through the project“Severo Ochoa Programme for Centres of Excellence in R&D”(Grant No.CEX2018-000797-S).
文摘The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects.These models necessitate defining breach geometry and formation time,for which various parametric models have been proposed.These models yield different values for average breach width,time of failure,and consequently,peak flows,as demonstrated by several researchers.This study analyzed the effect of selecting a breach parametric model on the hydraulic variables,potential damages,and hazard classification of structures.Three common parametric models were compared using a set of synthetic cases and a real off-stream reservoir.Results indicated significant effects of model choice.Material erodibility exerted a significant impact,surpassing that of failure mode.Other factors,such as the Manning coefficient,significantly affected the results.Utilizing an inadequate model or lacking information on dike material can lead to overly conservative or underestimated outcomes,thereby affecting hazard classification.
文摘Since the 21st century, the world is facing increasingly severe disaster problems, which greatly affect the development of human economy. As one of the natural disasters, the study of marine geological disasters is becoming a research hotspot. From the perspective of disaster mechanism, this paper reviews the classification methods of marine geological disasters from 1980 to now, and discusses the genetic mechanism of typical marine geological disasters on the continental margin, which provides scientific basis for the construction of marine engineering.
基金financially supported by Key Research and Development Project of China(Grant No.2022YFD2002400)the Key Scientific and Technological Projects in Key Areas of Crops(Grant No.2023AB014)+2 种基金the National Natural Science Foundation of China(Grant No.31901401)the Key Area Research and Development Program of Guangdong(Grant No.2023B0202130001)Guangdong Provincial Basic and Applied Basic Research Fund Project(Grant No.2022A1515011528).
文摘The primary aim of this study was to classify the hazard level of brown planthopper(BPH)damage in rice.Three datasets,including spectral reflectance corresponding to the sensitive wavelengths from rice canopy spectral wavelengths,rice stem spectral wavelengths,and fusion information of rice canopy and stem spectral wavelengths were used for BPH hazard level classification by using different algorithms.Datasets and algorithms were optimized by the BPH hazard level classification effects(which was evaluated by indices of accuracy,precision,recall,F_(1),and k-value).The optimized algorithm combination was used to build a hazard level classification model for spectral reflectance corresponding to the sensitive wavelength from the rice canopy spectral images.Results showed that:(1)The spectral reflectance corresponding to the sensitive wavelengths of fusion information dataset performed best in BPH hazard level classification,with the highest accuracy(99.08%),precision(99.31%),recall(98.83%),F_(1)(0.99),and k-value(0.99).(2)The optimum algorithm combination was Savitzky-Golay(S-G)smoothing,principal component analysis(PCA)for sensitive wavelength selection,and broad-learning system(BLS)for modeling.(3)The spectral reflectance corresponding to the sensitive wavelengths dataset of rice canopy spectral images achieved accuracy(80.63%),precision(80.28%),recall(77.03%),F_(1)(0.79),and k-value(0.74)in classifying BPH hazard level by using the optimum algorithm combination.
