The three-dimensional reconstruction of porous media is of great significance to the research of mechanisms of fluid flow.The real three-dimensional structural data of porous media are helpful to describe the irregula...The three-dimensional reconstruction of porous media is of great significance to the research of mechanisms of fluid flow.The real three-dimensional structural data of porous media are helpful to describe the irregular topologic structures in porous media.The reconstruction of porous media will be inaccurate while only hard data or no conditional data are available.Reconstructed results can be more accurate,using soft data during reconstruction.Integrating soft data with hard data,a method based on multiple-point geostatistics(MPS)is proposed to reconstruct three-dimensional structures of porous media.The variogram curves and permeability,computed by lattice Boltzmann method(LBM),of the reconstructed images and the target image obtained from real volume data were compared,showing that the structural characteristics of reconstructed porous media using both soft data and hard data as conditional data are most similar to those of real volume data.展开更多
Missing data are always an issue in community-based longitudinal studies, calling into question the representativeness of samples and bias in conclusions, the research has generated. This may be due to the difficulty ...Missing data are always an issue in community-based longitudinal studies, calling into question the representativeness of samples and bias in conclusions, the research has generated. This may be due to the difficulty of implementing random sampling procedures in these studies and/or the inherent difficulty in sampling hard-to-reach segments of the population being studied. In fact, the ability to accurately study hard-to-reach populations in light of potential bias created by missing data remains an open question. In this study, missing data are defined as both failure to interview potential research participants identified in the sampling frame and failure to retain enrolled research participants longitudinally. Using the sample from the Mobile Youth Survey, a multiple-cohort, longitudinal study of adolescents living in highly impoverished neighborhoods in Mobile, Alabama, we examined sample representativeness and dropout to determine whether missing data led to a nonrepresentative, and therefore, biased sample. Results indicate that even though random procedures are not strictly used to draw the sample, (a) the sample appears to be largely representative of the population that was studied, and (b) attrition is largely uncorrelated with characteristics of those who dropped out. This suggests that it is possible to study with validity hard-to reach populations in community settings.展开更多
Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could ...Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could be transmitted to navigation systems such as Waze. This study reports on the deployment and impact evaluation of digital alerts on motorist’s assistance patrols and 19 Queue trucks in Indiana. The motorist assistance patrol evaluation is provided qualitatively. A novel analysis of queue warning trucks equipped with digital alerts was conducted during the months of May-July in 2021 using connected vehicle data. This new data set reports locations of anonymous hard-braking events from connected vehicles on the Interstate. Hard-braking events were tabulated for when queueing occurred with and without the presence of a queue warning truck. Approximately 370 hours of queueing with queue trucks present and 58 hours of queueing without queue truck<span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> present were evaluated. Hard-braking events were found to decrease approximately 80% when queue warning trucks were used to alert motorists of impending queues.</span>展开更多
According to relevant data statistics, each year, nearly 70% of users have disc data loss because of misuse, viral damage, physical damage and hardware failure, bringing irreparable damage to enterprises, institutions...According to relevant data statistics, each year, nearly 70% of users have disc data loss because of misuse, viral damage, physical damage and hardware failure, bringing irreparable damage to enterprises, institutions and individuals. So data recovery technology has attracted wide attention of users and how to use data recovery technology to help to recover lost data and to minimize the loss has become an urgent need. This paper starts from the software and hardware failure to analyze two aspects of hard disk data loss, data storage structure theory, and combined with practical experience, it elaborates data damage type and related recovery methods.展开更多
针对数据存储中心硬盘故障数据稀少造成的故障预测效果不佳的问题,面向自我检测分析与报告技术(self-monitoring analysis and reporting technology,SMART)数据信息的时序特征,提出一种通过数据增强解决不平衡问题的硬盘故障预测算法...针对数据存储中心硬盘故障数据稀少造成的故障预测效果不佳的问题,面向自我检测分析与报告技术(self-monitoring analysis and reporting technology,SMART)数据信息的时序特征,提出一种通过数据增强解决不平衡问题的硬盘故障预测算法。该算法利用长短期记忆网络改进传统的生成对抗网络,生成包含故障恶化趋势信息的序列段数据,解决了数据集不平衡问题。同时,为进一步提高预测性能,预测模型融合了时序注意力机制和特征注意力机制,挖掘不同SMART特征和时间步对硬盘故障恶化过程的敏感程度。此外,在特征选择阶段结合了多种典型特征选择算法来选取关键特征。在真实硬盘数据集上进行了实验验证,结果表明,所提算法的准确率、召回率和F 1值均有较大提升。展开更多
以经典教学项目水的总硬度测定实验为切入点,创新性地构建基于ASP(Application Service Provider)服务架构与Access数据库的动态数据处理平台。该平台通过在线计算模块、实时数据协同和可视化分析系统3大核心功能,实现了实验数据的智能...以经典教学项目水的总硬度测定实验为切入点,创新性地构建基于ASP(Application Service Provider)服务架构与Access数据库的动态数据处理平台。该平台通过在线计算模块、实时数据协同和可视化分析系统3大核心功能,实现了实验数据的智能化处理、全过程可追溯管理。教学实践表明,该技术方案不仅使传统EDTA滴定法的数据处理效率提升,还提升了异常数据的溯源分析能力,为分析化学实验教学的数字化转型提供了可复制的技术范式。展开更多
基金Supported by the National Basic Research Program of China(Grant No.2006CB705805)National Natural Science Foundation of China(Grant Nos.10672159,10702069)
文摘The three-dimensional reconstruction of porous media is of great significance to the research of mechanisms of fluid flow.The real three-dimensional structural data of porous media are helpful to describe the irregular topologic structures in porous media.The reconstruction of porous media will be inaccurate while only hard data or no conditional data are available.Reconstructed results can be more accurate,using soft data during reconstruction.Integrating soft data with hard data,a method based on multiple-point geostatistics(MPS)is proposed to reconstruct three-dimensional structures of porous media.The variogram curves and permeability,computed by lattice Boltzmann method(LBM),of the reconstructed images and the target image obtained from real volume data were compared,showing that the structural characteristics of reconstructed porous media using both soft data and hard data as conditional data are most similar to those of real volume data.
文摘Missing data are always an issue in community-based longitudinal studies, calling into question the representativeness of samples and bias in conclusions, the research has generated. This may be due to the difficulty of implementing random sampling procedures in these studies and/or the inherent difficulty in sampling hard-to-reach segments of the population being studied. In fact, the ability to accurately study hard-to-reach populations in light of potential bias created by missing data remains an open question. In this study, missing data are defined as both failure to interview potential research participants identified in the sampling frame and failure to retain enrolled research participants longitudinally. Using the sample from the Mobile Youth Survey, a multiple-cohort, longitudinal study of adolescents living in highly impoverished neighborhoods in Mobile, Alabama, we examined sample representativeness and dropout to determine whether missing data led to a nonrepresentative, and therefore, biased sample. Results indicate that even though random procedures are not strictly used to draw the sample, (a) the sample appears to be largely representative of the population that was studied, and (b) attrition is largely uncorrelated with characteristics of those who dropped out. This suggests that it is possible to study with validity hard-to reach populations in community settings.
文摘Back of queue crashes on Interstates are a major concern for all state transportation departments. In 2020, Indiana DOT begin deploying queue warning trucks with message boards, flashers and digital alerts that could be transmitted to navigation systems such as Waze. This study reports on the deployment and impact evaluation of digital alerts on motorist’s assistance patrols and 19 Queue trucks in Indiana. The motorist assistance patrol evaluation is provided qualitatively. A novel analysis of queue warning trucks equipped with digital alerts was conducted during the months of May-July in 2021 using connected vehicle data. This new data set reports locations of anonymous hard-braking events from connected vehicles on the Interstate. Hard-braking events were tabulated for when queueing occurred with and without the presence of a queue warning truck. Approximately 370 hours of queueing with queue trucks present and 58 hours of queueing without queue truck<span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> present were evaluated. Hard-braking events were found to decrease approximately 80% when queue warning trucks were used to alert motorists of impending queues.</span>
文摘According to relevant data statistics, each year, nearly 70% of users have disc data loss because of misuse, viral damage, physical damage and hardware failure, bringing irreparable damage to enterprises, institutions and individuals. So data recovery technology has attracted wide attention of users and how to use data recovery technology to help to recover lost data and to minimize the loss has become an urgent need. This paper starts from the software and hardware failure to analyze two aspects of hard disk data loss, data storage structure theory, and combined with practical experience, it elaborates data damage type and related recovery methods.
文摘以经典教学项目水的总硬度测定实验为切入点,创新性地构建基于ASP(Application Service Provider)服务架构与Access数据库的动态数据处理平台。该平台通过在线计算模块、实时数据协同和可视化分析系统3大核心功能,实现了实验数据的智能化处理、全过程可追溯管理。教学实践表明,该技术方案不仅使传统EDTA滴定法的数据处理效率提升,还提升了异常数据的溯源分析能力,为分析化学实验教学的数字化转型提供了可复制的技术范式。
