In this paper a rainfall threshold and a Bayesian probability model are presented for the landslide occurrence of shallow landslides in Ha Giang city and the surroundings, Vietnam. The model requires the data on daily...In this paper a rainfall threshold and a Bayesian probability model are presented for the landslide occurrence of shallow landslides in Ha Giang city and the surroundings, Vietnam. The model requires the data on daily rainfall combined with the actual dates of landslide occurrences. Careful study on the database is a prerequisite for the paper. For this reason, selecting the input data was carried out carefully to ensure the reliable results of the study. The daily rainfall data covering a time span of 57 years was collected from a unique rain gauge station of National Centre for Hydro-meteorological Forecasting of Vietnam (from 1957 to 2013) and a landslide database with some landslides (37 of total of 245 landslides) that containing dates of occurrence, was prepared from historical records for the period 1989 to 2013. Rainfall thresholds were generated for the study area based on the relationship between daily and antecedent rainfall of the landslide events. The results shows that 3-day antecedent rainfall (with the rainfall threshold was established: RT = 40.8 −0.201R3ad) gives the best fit for the existing landslides in the landslide database. The Bayesian probability model for one-dimensional case was established based on 26 landslides for the period 1989 to 2009, daily rainfall data with the same time and the values of probability varies from 0.03 to 0.44. Next, the Bayesian probability model for two-dimensional case was generated based on 11 landslides, rainfall intensity and duration in three months (May, June and July) of 2013 and the values of probability ranges from 0.08 to 0.67, and computed values of conditional landslide probability P(A|B) from two-dimensional case of Bayesian approach are clearly controlled by rainfall intensity > 40 mm with rainfall duration > 0.3 day.展开更多
本研究基于水资源、社会、经济和生态4个维度构建水资源承载力评价体系,并采用改进的逼近理想解排序模型(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)对中国西北省会城市及典型城市2010—2022年的水资...本研究基于水资源、社会、经济和生态4个维度构建水资源承载力评价体系,并采用改进的逼近理想解排序模型(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)对中国西北省会城市及典型城市2010—2022年的水资源承载力进行评价。研究首次引入贝叶斯优化算法进行水资源优化配置,并据此计算各产业的水资源可支撑发展阈值。研究结果表明:(1)中国西北省会城市及典型城市2010—2022年的水资源承载力平均值在0.3~0.5之间,处于中等水平,除石嘴山市、西安市和银川市外,其余城市的水资源承载力均呈现显著提升趋势(P<0.05)。(2)水资源维度对水资源承载力的影响最大,其次为社会和生态维度,经济维度影响最小。(3)基于2022年数据的优化配置结果显示,农业用水量与生态用水量有所减少,而工业用水量与生活用水量显著增加。各城市在最优用水配置下的预估综合效益与总GDP均优于现状,其中石嘴山市的优化效果最为显著,综合效益得分提升41.49%。本研究可为中国西北省会城市及典型城市的水资源可持续开发利用与合理优化配置提供科学依据。展开更多
The Sierra Norte de Puebla, Mexico, has a record of hundreds of mass removal processes triggered by rainfall, where the intensity and duration of the rain are the main mechanisms. In order to determine threshold value...The Sierra Norte de Puebla, Mexico, has a record of hundreds of mass removal processes triggered by rainfall, where the intensity and duration of the rain are the main mechanisms. In order to determine threshold values for precipitation as a cause of a landslide, the prior, marginal and conditional probabilities were calculated. A Bayesian method was used for one-dimensional (precipitation intensity) and two-dimensional (precipitation intensity and duration) analysis. This suggested a high probability of mass movement when the precipitation exceeds 60 mm within ten days. A proposed warning system is based on classes in which the threshold is exceeded.展开更多
We consider the response of a test subject upon a skin area being heated with an electromagnetic wave or a contact surface. When the specifications of the electromagnetic beam are fixed, the stimulus is solely describ...We consider the response of a test subject upon a skin area being heated with an electromagnetic wave or a contact surface. When the specifications of the electromagnetic beam are fixed, the stimulus is solely described by the heating duration. The binary response of a subject, escape or no escape, is determined by the stimulus and a subjective threshold that varies among test realizations. We study four methods for inferring the median subjective threshold in psychophysical experiments: 1) sample median, 2) maximum likelihood estimation (MLE) with 2 variables, 3) MLE with 1 variable, and 4) adaptive Bayesian method. While methods 1 - 3 require samples of time to escape measured in the method of limits, method 4 utilizes binary outcomes observed in the method of constant stimuli. We find that a) the adaptive Bayesian method converges and is as efficient as the sample median even when the assumed model distribution is incorrect;b) this robust convergence is lost if we infer the mean instead of the median;c) for the optimal performance in an uncertain situation, it is best to use a wide model distribution;d) the predicted error from the posterior standard deviation is unreliable, dominated by the assumed model distribution.展开更多
提出了基于高频涡流检测(high frequency eddy current testing, HF-ECT)扫描成像的印刷电路板(printed circuit board, PCB)在线检测方法,利用板中导线、焊盘、引脚与基材之间的电导率差异来提取涡流响应信号并成像,实现对导线断线、...提出了基于高频涡流检测(high frequency eddy current testing, HF-ECT)扫描成像的印刷电路板(printed circuit board, PCB)在线检测方法,利用板中导线、焊盘、引脚与基材之间的电导率差异来提取涡流响应信号并成像,实现对导线断线、焊盘和引脚翘曲、脱落等损伤的高分辨率检测。首先根据线圈激励(频率高达2 MHz)下的涡流分布和成像特性分析印刷电路板的扫描图像特点,并研究图像的染色方法,以达到最佳的像素梯度分布特性;接着,提出基于贝叶斯模型的图像阈值分割和损伤区域提取方法,根据像素灰度分布的后验概率推导出图像分割的最佳阈值,通过对分割后二值图像的边界提取并对其中的损伤进行识别定位;最后将提出的方法应用到PCB的损伤检测中,验证不同条件下的损伤识别和定位效果。研究为印刷电路板的结构表征和损伤检测提供了一种新的途径。展开更多
文摘In this paper a rainfall threshold and a Bayesian probability model are presented for the landslide occurrence of shallow landslides in Ha Giang city and the surroundings, Vietnam. The model requires the data on daily rainfall combined with the actual dates of landslide occurrences. Careful study on the database is a prerequisite for the paper. For this reason, selecting the input data was carried out carefully to ensure the reliable results of the study. The daily rainfall data covering a time span of 57 years was collected from a unique rain gauge station of National Centre for Hydro-meteorological Forecasting of Vietnam (from 1957 to 2013) and a landslide database with some landslides (37 of total of 245 landslides) that containing dates of occurrence, was prepared from historical records for the period 1989 to 2013. Rainfall thresholds were generated for the study area based on the relationship between daily and antecedent rainfall of the landslide events. The results shows that 3-day antecedent rainfall (with the rainfall threshold was established: RT = 40.8 −0.201R3ad) gives the best fit for the existing landslides in the landslide database. The Bayesian probability model for one-dimensional case was established based on 26 landslides for the period 1989 to 2009, daily rainfall data with the same time and the values of probability varies from 0.03 to 0.44. Next, the Bayesian probability model for two-dimensional case was generated based on 11 landslides, rainfall intensity and duration in three months (May, June and July) of 2013 and the values of probability ranges from 0.08 to 0.67, and computed values of conditional landslide probability P(A|B) from two-dimensional case of Bayesian approach are clearly controlled by rainfall intensity > 40 mm with rainfall duration > 0.3 day.
文摘本研究基于水资源、社会、经济和生态4个维度构建水资源承载力评价体系,并采用改进的逼近理想解排序模型(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)对中国西北省会城市及典型城市2010—2022年的水资源承载力进行评价。研究首次引入贝叶斯优化算法进行水资源优化配置,并据此计算各产业的水资源可支撑发展阈值。研究结果表明:(1)中国西北省会城市及典型城市2010—2022年的水资源承载力平均值在0.3~0.5之间,处于中等水平,除石嘴山市、西安市和银川市外,其余城市的水资源承载力均呈现显著提升趋势(P<0.05)。(2)水资源维度对水资源承载力的影响最大,其次为社会和生态维度,经济维度影响最小。(3)基于2022年数据的优化配置结果显示,农业用水量与生态用水量有所减少,而工业用水量与生活用水量显著增加。各城市在最优用水配置下的预估综合效益与总GDP均优于现状,其中石嘴山市的优化效果最为显著,综合效益得分提升41.49%。本研究可为中国西北省会城市及典型城市的水资源可持续开发利用与合理优化配置提供科学依据。
文摘The Sierra Norte de Puebla, Mexico, has a record of hundreds of mass removal processes triggered by rainfall, where the intensity and duration of the rain are the main mechanisms. In order to determine threshold values for precipitation as a cause of a landslide, the prior, marginal and conditional probabilities were calculated. A Bayesian method was used for one-dimensional (precipitation intensity) and two-dimensional (precipitation intensity and duration) analysis. This suggested a high probability of mass movement when the precipitation exceeds 60 mm within ten days. A proposed warning system is based on classes in which the threshold is exceeded.
文摘We consider the response of a test subject upon a skin area being heated with an electromagnetic wave or a contact surface. When the specifications of the electromagnetic beam are fixed, the stimulus is solely described by the heating duration. The binary response of a subject, escape or no escape, is determined by the stimulus and a subjective threshold that varies among test realizations. We study four methods for inferring the median subjective threshold in psychophysical experiments: 1) sample median, 2) maximum likelihood estimation (MLE) with 2 variables, 3) MLE with 1 variable, and 4) adaptive Bayesian method. While methods 1 - 3 require samples of time to escape measured in the method of limits, method 4 utilizes binary outcomes observed in the method of constant stimuli. We find that a) the adaptive Bayesian method converges and is as efficient as the sample median even when the assumed model distribution is incorrect;b) this robust convergence is lost if we infer the mean instead of the median;c) for the optimal performance in an uncertain situation, it is best to use a wide model distribution;d) the predicted error from the posterior standard deviation is unreliable, dominated by the assumed model distribution.
文摘提出了基于高频涡流检测(high frequency eddy current testing, HF-ECT)扫描成像的印刷电路板(printed circuit board, PCB)在线检测方法,利用板中导线、焊盘、引脚与基材之间的电导率差异来提取涡流响应信号并成像,实现对导线断线、焊盘和引脚翘曲、脱落等损伤的高分辨率检测。首先根据线圈激励(频率高达2 MHz)下的涡流分布和成像特性分析印刷电路板的扫描图像特点,并研究图像的染色方法,以达到最佳的像素梯度分布特性;接着,提出基于贝叶斯模型的图像阈值分割和损伤区域提取方法,根据像素灰度分布的后验概率推导出图像分割的最佳阈值,通过对分割后二值图像的边界提取并对其中的损伤进行识别定位;最后将提出的方法应用到PCB的损伤检测中,验证不同条件下的损伤识别和定位效果。研究为印刷电路板的结构表征和损伤检测提供了一种新的途径。
