The processor and the main memory in the traditional computing system cannot satisfy the requirements of the emerging large-scale applications in terms of computing power and memory capacity.Tackling with such challen...The processor and the main memory in the traditional computing system cannot satisfy the requirements of the emerging large-scale applications in terms of computing power and memory capacity.Tackling with such challenges,heterogeneous computing systems,which consist of specialized accelerators and high-performance storage devices,have demonstrated their superiority in various computing domains.However,data migration between the accelerators and the storage devices becomes the major performance bottleneck in such computing systems owing to the long data path imposed by the stale Von Neumann architecture.There already exist plenty of discussions on the software and hardware techniques to resolve the data migration issues in the heterogeneous computing system.In this paper,we present a survey of these techniques with respect to the system designs,architectural innovations,and application-level optimizations.We expect our survey would aid the development of the research community and inspire the researchers,who are interested in the relevant areas.展开更多
Field experimental seismic sounding permitted us to obtain optimal shallow seismic reflection sounding parameters.In process of data processing,we obtained a high-qualitative shallow seismic reflection sounding profil...Field experimental seismic sounding permitted us to obtain optimal shallow seismic reflection sounding parameters.In process of data processing,we obtained a high-qualitative shallow seismic reflection sounding profile by using the techniques such as filtering,edition surgical blanking,prediction deconvolution,fitting static correlation of first arrival time,and velocity analysis.Comprehensive analysis on the information of reflection wave groups along the seismic sounding profile and the stratigraphic and neogeochronological data obtained from many drills near the sounding line reveals that the upper termination of the detected fault zone is located at depth of 75~80 m,in the Middle Pleistocene deposits dated to be about 220 ka BP.The continuity,discontinuity,increasing and decreasing amount of reflection wave groups and change of their configurations,in combination with geological columns of drills,permitted us to know that the width of upper termination of the fault zone is 100 m.It can be inferred from the variation of number of reflection wave groups along the profile that the scarp of hidden fault is 200 m wide and the fault is a synsedimentary active fault in the Early Pleistocene and the early stage of Middle Pleistocene.No tectonic movement,which offset the covering deposits,had occurred since the late stage of Middle Pleistocene.展开更多
Today,lightweight virtualization technologies have been widely deployed on data centers and HPC clusters to provide highly efficient and elastic resource provisioning.Virtualization has also been extended to the I/O s...Today,lightweight virtualization technologies have been widely deployed on data centers and HPC clusters to provide highly efficient and elastic resource provisioning.Virtualization has also been extended to the I/O stack in operating system.For example,virtual switch has become the primary provider of I/O services for data movement among various light-weight virtual machines,such as Docker and Kubernetes.However,I/O stack virtualization introduces performance degradation and scalability bottleneck to the data movements of HPC computing framework,such as MPI based collective data movements and bursty asynchronous data movements.In order to study the bottleneck,we quantify and analyze the performance degradation involving with HPC data movements on virtual clusters.Then,we design a set of two-stage methods to proactively adapt the virtual network and data movement procedures.This can enhance the performance of HPC collective data movements by up to 3×.Meanwhile,a cross-layer middleware is designed to improve the performance and scalability of bursty asynchronous data movements.Our evaluation shows that it can improve the performance of real scientific application by 34.6%.展开更多
The process of mass movements and their consequent turbidity currents in large submarine canyons has been widely reported, however, little attention was paid to that in small canyons. In this paper, we document mass m...The process of mass movements and their consequent turbidity currents in large submarine canyons has been widely reported, however, little attention was paid to that in small canyons. In this paper, we document mass movements in small submarine canyons in the northeast of Baiyun deepwater area, north of the South China Sea （SCS）, and their strong effects on the evolution of the canyons based on geophysical data. Submarine canyons in the study area arrange closely below the shelf break zone which was at the depth of -500 m. Within submarine canyons, seabed surface was covered with amounts of failure scars resulted from past small-sized landslides. A complex process of mass transportation in the canyons is indicated by three directions of mass movements. Recent mass movement deposits in the canyons exhibit translucent reflections or parallel reflections which represent the brittle deformation and the plastic deformation, respectively. The area of most landslides in the canyons is less than 3 km2. The trigger mechanisms for mass movements in the study area are gravitational overloading, slope angle and weak properties of soil. Geophysical data indicate that the genesis of submarine canyons is the erosion of mass movements and consequent turbidity currents. The significant effects of mass movements on canyon are incision and sediment transportation at the erosion phases and fillings supply at the fill phases. This research will be helpful for the geological risk assessments and understanding the sediment transportation in the northern margin of the SCS.展开更多
Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation...Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.展开更多
Social media plays a crucial role in the organization of massive social movements. However, the sheer quantity of data generated by the events as well as the data collection restrictions that researchers encounter, le...Social media plays a crucial role in the organization of massive social movements. However, the sheer quantity of data generated by the events as well as the data collection restrictions that researchers encounter, leads to a series of challenges for researchers who want to analyze dynamic public discourse and opinion in response to and in the creation of world events. In this paper we present gatherTweet, a Python package that helps researchers efficiently collect social media data for events that are composed of many decentralized actions (across both space and time). The package is useful for studies that require analysis of the organizational or baseline messaging before an action, the action itself, and the effects of the action on subsequent public discourse. By capturing these aspects of world events gatherTweet enables the study of events and actions like protests, natural disasters, and elections.展开更多
RADARSAT data have a potential role for coastal pollution monitoring. This study presents a new approach to detect and forecast oil slick trajectory movements. The oil slick trajectory movements is based on the tidal ...RADARSAT data have a potential role for coastal pollution monitoring. This study presents a new approach to detect and forecast oil slick trajectory movements. The oil slick trajectory movements is based on the tidal current effects and Fay's algorithm for oil slick spreading mechanisms. The oil spill trajectory model contains the integration between Doppler frequency shift model and Lagrangian model. Doppler frequency shift model implemented to simulate tidal current pattern from RADARSAT data while the Lagrangian model used to predict oil spill spreading pattern. The classical Fay's algorithm was implemented with the two models to simulate the oil spill trajectory movements.The study shows that the slick lengths are effected by tidal current V component with maximum velocity of 1.4 m/s. This indicates that oil slick trajectory path is moved towards the north direction. The oil slick parcels are accumulated along the coastline after 48 h. The analysis indicated that tidal current V components were the dominant forcing for oil slick spreading.展开更多
On the basis of GPS observations in Yunnan from 1999 to 2001, we adopt the robust Bayesian least square estimation and multi fault dislocation model to analyze the quantitative kinematics models of the main faults in ...On the basis of GPS observations in Yunnan from 1999 to 2001, we adopt the robust Bayesian least square estimation and multi fault dislocation model to analyze the quantitative kinematics models of the main faults in Yunnan. The geodetic inversion suggests that: (1) The horizontal movement of crust in Yunnan is affected distinctly by fault activity whose characters are consistent with geological results; (2) The activity of the north segment of the Red River fault zone is maximum, in the middle segment is moderate, and in the south segment is minimum; (3)Among others, the Xiaojiang fault zone has the strongest activity, the secondary are the Lancang fault zone and the north segment of Nujiang fault zone, the Qujiang fault zone shows the characteristic of hinge fault; (4)Each fault could produce an earthquake of M s=6 more or less per year; (5) The larger value of maximum shear strain are mostly located along the main active fault zones and their intersections; earthquakes did not occur at the place of maximum shear strain, and mostly take place at the higher gradient zones, especially at its corner.展开更多
Real vehicle tracking data play an important role in the research of routing in vehicle sensor networks. Most of the vehicle tracking data, however, were collected periodically and could not meet the requirements of r...Real vehicle tracking data play an important role in the research of routing in vehicle sensor networks. Most of the vehicle tracking data, however, were collected periodically and could not meet the requirements of real-time by many applications. Most of the existing trace interpolation algorithms use uniform interpolation methods and have low accuracy problem. From our observation, intersection vehicle status is critical to the vehicle movement. In this paper, we proposed a novel trace interpolation algorithm. Our algorithm used intersection vehicle movement modeling (IVMM) and velocity data mining (VDM) to assist the interpolation process. The algorithm is evaluated with real vehicle GPS data. Results show that our algorithm has much higher accuracy than traditional trace interpolation algorithms.展开更多
Scientific workflows are essential to modern scientific computing,yet traditional execution approaches-based on control-flow paradigms and disk-based data transfers-struggle as data movement,rather than computation,em...Scientific workflows are essential to modern scientific computing,yet traditional execution approaches-based on control-flow paradigms and disk-based data transfers-struggle as data movement,rather than computation,emerges as the dominant performance bottleneck.These methods suffer from long latency due to centralized orchestration,sequential task triggering,and inefficient disk-mediated exchanges.We propose HPCFlow,a data-flow-oriented workflow framework designed for high-performance computing(HPC)environments.HPCFlow supports decentralized,input-driven execution.Functions are decomposed into computation and data transmission,enabling asynchronous data propagation and efficient overlap.HPCFlow incorporates context-aware data transfer strategies and alleviates small-file I/O inefficiencies through mini-batching.Additionally,HPCFlow implements an input synchronization mechanism to guarantee data completeness during parallel execution under elastic scaling conditions.Empirical results from a production HPC environment demonstrate that compared to a control-flow baseline,HPCFlow significantly reduces makespan and end-to-end latency,achieves efficient overlap,and alleviates pressure on network file systems,thereby validating its effectiveness for data-intensive scientific workflows.展开更多
The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new ...The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage （UPMS） with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.展开更多
目的:分析药源性运动障碍(drug-induced movement disorders,DIMDs)发生特点、关联药品及其风险信号。方法:提取解放军药品不良反应监测中心数据库2009年1月1日至2022年12月31日的神经系统相关自发报告,筛选出DIMDs报告,对患者的一般情...目的:分析药源性运动障碍(drug-induced movement disorders,DIMDs)发生特点、关联药品及其风险信号。方法:提取解放军药品不良反应监测中心数据库2009年1月1日至2022年12月31日的神经系统相关自发报告,筛选出DIMDs报告,对患者的一般情况、相关药品分布特征等信息进行回顾分析,并采用报告比值比法、比例报告比法、贝叶斯可信区间递进神经网络法、英国药品和保健产品管理局综合标准法4种数据挖掘技术获取相关药品风险信号。结果:经筛选得到DIMDs报告2025例,分别在全部ADR和神经精神疾病ADR报告中占比为0.72%和6.63%。男女比为1.12∶1,多见于65岁以上人群。相关药品类型例数排名前3位的是中枢神经系统用药、抗感染药物和呼吸系统用药,严重ADR出现频次排名前3的是莫西沙星、亚胺培南-西司他丁钠、左氧氟沙星。共有31种药品在4种数据挖掘方法中均产生信号,其中信号强度排名前3位的是莫西沙星、异丙托溴铵、特布他林。结论:应加强中枢神经系统用药、抗感染药物和呼吸系统用药的临床应用监测,警惕高风险药品使用过程中可能出现的肌肉不自主收缩、震颤等ADR的发生,为临床尽早识别干预DIMDs提供参考。展开更多
基金supported by Peking University start-up package(7100603645).
文摘The processor and the main memory in the traditional computing system cannot satisfy the requirements of the emerging large-scale applications in terms of computing power and memory capacity.Tackling with such challenges,heterogeneous computing systems,which consist of specialized accelerators and high-performance storage devices,have demonstrated their superiority in various computing domains.However,data migration between the accelerators and the storage devices becomes the major performance bottleneck in such computing systems owing to the long data path imposed by the stale Von Neumann architecture.There already exist plenty of discussions on the software and hardware techniques to resolve the data migration issues in the heterogeneous computing system.In this paper,we present a survey of these techniques with respect to the system designs,architectural innovations,and application-level optimizations.We expect our survey would aid the development of the research community and inspire the researchers,who are interested in the relevant areas.
基金A High-new Technique Project by State Development and Planning Commission of China (2001977).
文摘Field experimental seismic sounding permitted us to obtain optimal shallow seismic reflection sounding parameters.In process of data processing,we obtained a high-qualitative shallow seismic reflection sounding profile by using the techniques such as filtering,edition surgical blanking,prediction deconvolution,fitting static correlation of first arrival time,and velocity analysis.Comprehensive analysis on the information of reflection wave groups along the seismic sounding profile and the stratigraphic and neogeochronological data obtained from many drills near the sounding line reveals that the upper termination of the detected fault zone is located at depth of 75~80 m,in the Middle Pleistocene deposits dated to be about 220 ka BP.The continuity,discontinuity,increasing and decreasing amount of reflection wave groups and change of their configurations,in combination with geological columns of drills,permitted us to know that the width of upper termination of the fault zone is 100 m.It can be inferred from the variation of number of reflection wave groups along the profile that the scarp of hidden fault is 200 m wide and the fault is a synsedimentary active fault in the Early Pleistocene and the early stage of Middle Pleistocene.No tectonic movement,which offset the covering deposits,had occurred since the late stage of Middle Pleistocene.
基金supported by National Key R&D Program of China under Grant No.2018YFB0204303,NSFC U1811461Guangdong Natural Science Foundation 2018B030312002the Major Program of Guangdong Basic and Applied Research 2019B030302002.
文摘Today,lightweight virtualization technologies have been widely deployed on data centers and HPC clusters to provide highly efficient and elastic resource provisioning.Virtualization has also been extended to the I/O stack in operating system.For example,virtual switch has become the primary provider of I/O services for data movement among various light-weight virtual machines,such as Docker and Kubernetes.However,I/O stack virtualization introduces performance degradation and scalability bottleneck to the data movements of HPC computing framework,such as MPI based collective data movements and bursty asynchronous data movements.In order to study the bottleneck,we quantify and analyze the performance degradation involving with HPC data movements on virtual clusters.Then,we design a set of two-stage methods to proactively adapt the virtual network and data movement procedures.This can enhance the performance of HPC collective data movements by up to 3×.Meanwhile,a cross-layer middleware is designed to improve the performance and scalability of bursty asynchronous data movements.Our evaluation shows that it can improve the performance of real scientific application by 34.6%.
基金The National Science and Technology Major Project under contract No.2011ZX05056-001-02
文摘The process of mass movements and their consequent turbidity currents in large submarine canyons has been widely reported, however, little attention was paid to that in small canyons. In this paper, we document mass movements in small submarine canyons in the northeast of Baiyun deepwater area, north of the South China Sea （SCS）, and their strong effects on the evolution of the canyons based on geophysical data. Submarine canyons in the study area arrange closely below the shelf break zone which was at the depth of -500 m. Within submarine canyons, seabed surface was covered with amounts of failure scars resulted from past small-sized landslides. A complex process of mass transportation in the canyons is indicated by three directions of mass movements. Recent mass movement deposits in the canyons exhibit translucent reflections or parallel reflections which represent the brittle deformation and the plastic deformation, respectively. The area of most landslides in the canyons is less than 3 km2. The trigger mechanisms for mass movements in the study area are gravitational overloading, slope angle and weak properties of soil. Geophysical data indicate that the genesis of submarine canyons is the erosion of mass movements and consequent turbidity currents. The significant effects of mass movements on canyon are incision and sediment transportation at the erosion phases and fillings supply at the fill phases. This research will be helpful for the geological risk assessments and understanding the sediment transportation in the northern margin of the SCS.
基金The Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics under contract No.SOED1402the Youth Science and Technology Foundation of East China Sea Branch,SOA under contract No.201624
文摘Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.
文摘Social media plays a crucial role in the organization of massive social movements. However, the sheer quantity of data generated by the events as well as the data collection restrictions that researchers encounter, leads to a series of challenges for researchers who want to analyze dynamic public discourse and opinion in response to and in the creation of world events. In this paper we present gatherTweet, a Python package that helps researchers efficiently collect social media data for events that are composed of many decentralized actions (across both space and time). The package is useful for studies that require analysis of the organizational or baseline messaging before an action, the action itself, and the effects of the action on subsequent public discourse. By capturing these aspects of world events gatherTweet enables the study of events and actions like protests, natural disasters, and elections.
文摘RADARSAT data have a potential role for coastal pollution monitoring. This study presents a new approach to detect and forecast oil slick trajectory movements. The oil slick trajectory movements is based on the tidal current effects and Fay's algorithm for oil slick spreading mechanisms. The oil spill trajectory model contains the integration between Doppler frequency shift model and Lagrangian model. Doppler frequency shift model implemented to simulate tidal current pattern from RADARSAT data while the Lagrangian model used to predict oil spill spreading pattern. The classical Fay's algorithm was implemented with the two models to simulate the oil spill trajectory movements.The study shows that the slick lengths are effected by tidal current V component with maximum velocity of 1.4 m/s. This indicates that oil slick trajectory path is moved towards the north direction. The oil slick parcels are accumulated along the coastline after 48 h. The analysis indicated that tidal current V components were the dominant forcing for oil slick spreading.
文摘On the basis of GPS observations in Yunnan from 1999 to 2001, we adopt the robust Bayesian least square estimation and multi fault dislocation model to analyze the quantitative kinematics models of the main faults in Yunnan. The geodetic inversion suggests that: (1) The horizontal movement of crust in Yunnan is affected distinctly by fault activity whose characters are consistent with geological results; (2) The activity of the north segment of the Red River fault zone is maximum, in the middle segment is moderate, and in the south segment is minimum; (3)Among others, the Xiaojiang fault zone has the strongest activity, the secondary are the Lancang fault zone and the north segment of Nujiang fault zone, the Qujiang fault zone shows the characteristic of hinge fault; (4)Each fault could produce an earthquake of M s=6 more or less per year; (5) The larger value of maximum shear strain are mostly located along the main active fault zones and their intersections; earthquakes did not occur at the place of maximum shear strain, and mostly take place at the higher gradient zones, especially at its corner.
文摘Real vehicle tracking data play an important role in the research of routing in vehicle sensor networks. Most of the vehicle tracking data, however, were collected periodically and could not meet the requirements of real-time by many applications. Most of the existing trace interpolation algorithms use uniform interpolation methods and have low accuracy problem. From our observation, intersection vehicle status is critical to the vehicle movement. In this paper, we proposed a novel trace interpolation algorithm. Our algorithm used intersection vehicle movement modeling (IVMM) and velocity data mining (VDM) to assist the interpolation process. The algorithm is evaluated with real vehicle GPS data. Results show that our algorithm has much higher accuracy than traditional trace interpolation algorithms.
基金supported by National Key R&D Program of China grant 2023YFB3002204.
文摘Scientific workflows are essential to modern scientific computing,yet traditional execution approaches-based on control-flow paradigms and disk-based data transfers-struggle as data movement,rather than computation,emerges as the dominant performance bottleneck.These methods suffer from long latency due to centralized orchestration,sequential task triggering,and inefficient disk-mediated exchanges.We propose HPCFlow,a data-flow-oriented workflow framework designed for high-performance computing(HPC)environments.HPCFlow supports decentralized,input-driven execution.Functions are decomposed into computation and data transmission,enabling asynchronous data propagation and efficient overlap.HPCFlow incorporates context-aware data transfer strategies and alleviates small-file I/O inefficiencies through mini-batching.Additionally,HPCFlow implements an input synchronization mechanism to guarantee data completeness during parallel execution under elastic scaling conditions.Empirical results from a production HPC environment demonstrate that compared to a control-flow baseline,HPCFlow significantly reduces makespan and end-to-end latency,achieves efficient overlap,and alleviates pressure on network file systems,thereby validating its effectiveness for data-intensive scientific workflows.
文摘The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage （UPMS） with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.
文摘目的:分析药源性运动障碍(drug-induced movement disorders,DIMDs)发生特点、关联药品及其风险信号。方法:提取解放军药品不良反应监测中心数据库2009年1月1日至2022年12月31日的神经系统相关自发报告,筛选出DIMDs报告,对患者的一般情况、相关药品分布特征等信息进行回顾分析,并采用报告比值比法、比例报告比法、贝叶斯可信区间递进神经网络法、英国药品和保健产品管理局综合标准法4种数据挖掘技术获取相关药品风险信号。结果:经筛选得到DIMDs报告2025例,分别在全部ADR和神经精神疾病ADR报告中占比为0.72%和6.63%。男女比为1.12∶1,多见于65岁以上人群。相关药品类型例数排名前3位的是中枢神经系统用药、抗感染药物和呼吸系统用药,严重ADR出现频次排名前3的是莫西沙星、亚胺培南-西司他丁钠、左氧氟沙星。共有31种药品在4种数据挖掘方法中均产生信号,其中信号强度排名前3位的是莫西沙星、异丙托溴铵、特布他林。结论:应加强中枢神经系统用药、抗感染药物和呼吸系统用药的临床应用监测,警惕高风险药品使用过程中可能出现的肌肉不自主收缩、震颤等ADR的发生,为临床尽早识别干预DIMDs提供参考。
