期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
地下快速路驾驶人速度感知敏感性分析及模型构建
1
作者 张兰芳 武雅婷 +1 位作者 王淑丽 史进 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2023年第1期83-90,共8页
为探究驾驶人速度感知机理,设计驾驶模拟实验采集驾驶人感知速度与实际行车速度,分析地下快速路几何线形、侧壁变化频率等因素对驾驶人速度感知敏感性的影响,并基于恒定速度理论、机器学习方法构建驾驶人速度感知偏差敏感性阈值预测模... 为探究驾驶人速度感知机理,设计驾驶模拟实验采集驾驶人感知速度与实际行车速度,分析地下快速路几何线形、侧壁变化频率等因素对驾驶人速度感知敏感性的影响,并基于恒定速度理论、机器学习方法构建驾驶人速度感知偏差敏感性阈值预测模型。结果表明,在0.05显著水平下,不同速度水平、线形组合、侧壁变化频率组别下,驾驶人的速度感知敏感性阈值都存在显著差异。采用LASSO(least absolute shrinkage and selection operator)筛选根据短期、中长期、长期时窗划分的各特征变量,构建的多元非线性模型的决定系数R2为0.645,多层感知机模型的决定系数R2为0.727,支持向量回归模型的决定系数R2为0.853。 展开更多
关键词 地下快速路 驾驶模拟 速度感知偏差 敏感性阈值 支持向量回归
下载PDF
加权模板匹配的二值化阈值不敏感性研究 被引量:3
2
作者 王刚 段会川 《计算机技术与发展》 2012年第1期122-125,共4页
数字图像二值化处理过程中,阈值的选取非常之关键,为了在实际应用中能够快速准确地匹配出二值化图像中的目标图像,文中采用模板匹配的方法,对标准模板匹配算法和加权模板匹配算法的二值化阈值敏感性进行了研究。根据实验图像在二值化处... 数字图像二值化处理过程中,阈值的选取非常之关键,为了在实际应用中能够快速准确地匹配出二值化图像中的目标图像,文中采用模板匹配的方法,对标准模板匹配算法和加权模板匹配算法的二值化阈值敏感性进行了研究。根据实验图像在二值化处理过程中所取阈值的波动对图像匹配结果的影响情况,得到加权模板匹配算法与标准模板匹配算法的二值化阈值敏感性差异。实验结论同时表明加权模板匹配算法具有较强的二值化阈值不敏感性和匹配性能好的优点。 展开更多
关键词 加权模板匹配 标准模板匹配 阈值敏感 二值化 权值矩阵
下载PDF
基于脉冲电流注入的差分芯片敏感度研究
3
作者 董亚运 崔志同 +4 位作者 杜传报 程引会 聂鑫 王文卓 郑生全 《太赫兹科学与电子信息学报》 2023年第12期1499-1506,共8页
采用脉冲电流注入(PCI)技术,对差分信号接收芯片(DS26C32ATM)的敏感阈值进行研究。试验结果表明,随着脉冲源电压的增大,传输线上的注入电流增大,差分信号接收芯片接口电路受到电磁脉冲干扰,发生损伤。对损伤芯片进行失效机理分析,定位... 采用脉冲电流注入(PCI)技术,对差分信号接收芯片(DS26C32ATM)的敏感阈值进行研究。试验结果表明,随着脉冲源电压的增大,传输线上的注入电流增大,差分信号接收芯片接口电路受到电磁脉冲干扰,发生损伤。对损伤芯片进行失效机理分析,定位故障。针对失效机理分析结果,对差分信号接收芯片进行加固防护研究。试验结果为后续差分芯片的抗电磁脉冲干扰的性能试验提供可靠依据。 展开更多
关键词 脉冲电流注入 差分芯片 电磁敏感性阈值 加固防护
下载PDF
融合方向特性与不确定性的脉冲噪声滤波 被引量:5
4
作者 齐现英 刘伯强 +1 位作者 徐建伟 宋莉 《中国图象图形学报》 CSCD 北大核心 2017年第6期754-766,共13页
目的随机噪声的噪声阈值具有不确定性和敏感性,寻找一个鲁棒的阀值是非常困难的,这严重影响了噪声的提取效率。为提高噪声判断的准确性,提出一种基于方向特性与中智不确定性融合的双端脉冲检测算法;另外,为加强优良像素在滤波过程中的权... 目的随机噪声的噪声阈值具有不确定性和敏感性,寻找一个鲁棒的阀值是非常困难的,这严重影响了噪声的提取效率。为提高噪声判断的准确性,提出一种基于方向特性与中智不确定性融合的双端脉冲检测算法;另外,为加强优良像素在滤波过程中的权重,构建了一种基于像素中智不确定性和ROAD(rank-ordered absolute differences)统计量的新型双边滤波函数。方法在噪声检测阶段,首先根据ROLD(rank-ordered logarithmic difference)与噪声阈值T的关系,将污染图像的像素分为超限域像素(ROLD≥T)、邻限域像素(0.8T≤ROLD<T)和安全域像素(ROLD<0.8T),并利用开关机制完成一次噪声检测。在此基础上,为提高超限域和邻限域像素噪声检测的准确性,采用不同策略对其进行二次噪声排查:对超限域像素,利用新型25像素和9像素4方向模板计算像素基于排序的方向对数差统计量,由该统计量与T的大小关系决定当前像素的噪声真伪;对邻限域像素,则结合当前像素中智不确定性在滤波窗内的排序信息来进一步确定其噪声特性。在滤波阶段,利用像素中智不确定性和ROAD统计量构建新型双边滤波函数,以加强低不确定性和高相似性像素在图像恢复中的权重。结果针对实验图像,双端脉冲检测算法的边缘像素提取率最高可达67%、邻限域像素的噪声剔除率最高可达91%,大大降低了阈值对噪声提取的敏感性,从而提高了噪声判断的正确率。在10%~80%噪声范围内,本文算法的主观性能和峰值信噪比都优于其他7种算法。结论本文基于双端检测和新型双边滤波函数的新算法,在噪声检测和去噪过程中均充分考虑了图像本身的方向性和噪声的不确定性,因此提高了噪声提取及像素滤波权重的准确性,从而有效地保护了图像的边缘和细节信息。 展开更多
关键词 随机脉冲噪声 阈值敏感 双端噪声检测 方向模板 中智不确定 新双边滤波
原文传递
Uncertainty in crossing time of 2 °C warming threshold over China 被引量:16
5
作者 Xiaolong Chen Tianjun Zhou 《Science Bulletin》 SCIE EI CAS CSCD 2016年第18期1451-1459,共9页
The 2 ℃ warming target has been used widely in global and regional climate change research. Previous studies have shown large uncertainties in the time when surface air temperature (SAT) change over China will reac... The 2 ℃ warming target has been used widely in global and regional climate change research. Previous studies have shown large uncertainties in the time when surface air temperature (SAT) change over China will reach 2℃ rela- tive to the pre-industrial era. To understand the uncertainties, we analyzed the projected SAT in the twenty-first century using 40 state-of-the-art climate models under two Repre- sentative Concentration Pathways (RCP4.5 and RCPS.5) from the Coupled Model Intercomparison Project Phase 5. The 2℃ threshold-crossing time (TCT) of SAT averaged across China was around 2033 and 2029 for RCP4.5 and RCP8.5, respectively. Considering a 4-1o- range of inter- model SAT change, the upper and lower bounds of the 2 ℃ TCT could differ by about 25 years or even more. Uncer- tainty in the projected SAT and the warming rate around the TCT are the two main factors responsible for the TCT uncertainty. The former is determined by the climate sensi- tivity represented by the global mean surface temperature response. About 45 % of the intermodel variance of the projected 2 ~C TCT for averaged SAT over China can be explained by climate sensitivity across the models, which is contributed mainly by central and southern China. In a cli- mate more sensitive to CO2 forcing, stronger greenhouse effect, less stratus cloud over the East Asian monsoon region, and less snow cover on the Tibetan Plateau result in increased downward longwave radiation, increased shortwave radia- tion, and decreased shortwave radiation reflected by the surface, respectively, all of which may advance the TCT. 展开更多
关键词 2 °C threshold Projection uncertainty China region CMIP5 Climate sensitivity
原文传递
Spatio-temporal analysis and simulation on shallow rainfall-induced landslides in China using landslide susceptibility dynamics and rainfall I-D thresholds 被引量:6
6
作者 LI WeiYue LIU Chun +7 位作者 Marco SCAIONI SUN WeiWei CHEN Yu YAO DongJing CHEN Sheng HONG Yang ZHANG KaiHang CHENG GuoDong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第4期720-732,共13页
An empirical simulation method to simulate the possible position of shallow rainfall-induced landslides in China has been developed.This study shows that such a simulation may be operated in real-time to highlight tho... An empirical simulation method to simulate the possible position of shallow rainfall-induced landslides in China has been developed.This study shows that such a simulation may be operated in real-time to highlight those areas that are highly prone to rainfall-induced landslides on the basis of the landslide susceptibility index and the rainfall intensity-duration(I-D) thresholds.First,the study on landslide susceptibility in China is introduced.The entire territory has been classified into five categories,among which high-susceptibility regions(Zone 4-'High' and 5-'Very high') account for 4.15%of the total extension of China.Second,rainfall is considered as an external triggering factor that may induce landslide initiation.Real-time satellite-based TMPA3B42 products may provide real rainfall spatial and temporal patterns,which may be used to derive rainfall duration time and intensity.By using a historical record of 60 significant past landslides,the rainfall I-D equation has been calibrated.The rainfall duration time that may trigger a landslide has resulted between 3 hours and 45 hours.The combination of these two aspects can be exploited to simulate the spatiotemporal distribution of rainfall-induced landslide hazards when rainfall events exceed the rainfall I-D thresholds,where the susceptibility category is 'high' or 'very high'.This study shows a useful tool to be part of a systematic landslide simulation methodology,potentially providing useful information for a theoretical basis and practical guide for landslide prediction and mitigation throughout China. 展开更多
关键词 Surface and subsurface runoff Runoff-produced physical and chemical deposits Precipitated salts and water circulation Groundwater supply mechanism Badain Jaran Desert
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部