A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data： attributes and documents describing each component. The paper discusses the v...A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data： attributes and documents describing each component. The paper discusses the version change relations between a sub-node component and a up-node component in a product structure tree, analyzes the version control system for a static reference and that for a dynamic reference and proposes a product structure model in support of dynamic reference, which is easy to use and contains a complete set of information providing an essential way of data organization for the PDM system.展开更多
The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplec...The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in detail.This chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective model.The construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass regions.It is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)shells.This is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm operation.Although the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard them.The results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.展开更多
Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic grap...Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.展开更多
Pipe cooling is an effective method of mass concrete temperature control, but its accurate and convenient numerical simulation is still a cumbersome problem. An improved embedded model, considering the water temperatu...Pipe cooling is an effective method of mass concrete temperature control, but its accurate and convenient numerical simulation is still a cumbersome problem. An improved embedded model, considering the water temperature variation along the pipe, was proposed for simulating the temperature field of early-age concrete structures containing cooling pipes. The improved model was verified with an engineering example. Then, the p-version self-adaption algorithm for the improved embedded model was deduced, and the initial values and boundary conditions were examined. Comparison of some numerical samples shows that the proposed model can provide satisfying precision and a higher efficiency. The analysis efficiency can be doubled at the same precision, even for a large-scale element. The p-version algorithm can fit grids of different sizes for the temperature field simulation. The convenience of the proposed algorithm lies in the possibility of locating more pipe segments in one element without the need of so regular a shape as in the explicit model.展开更多
By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal de...By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal demand system( RSDAIDS) is used to estimate the income and price elasticity of major imported agriculture textile material from the major sources based on the data from 1992 to 2015. The results are shown as follows.( 1) Although the dependency on imported cotton is lower than wool, the fluctuation of cotton import is much more drastic; China's demand for cotton is relatively price elastic with higher expenditure elasticity compared with wool; besides,the existence of complementarity is proved between imported cotton and wool.( 2) According to the import elasticity of cotton,demand for cotton imported from India shows priority over cotton from other sources; demand for cotton imported from America is the most price-sensitive one; substitution among cotton from different sources is weak.( 3) According to the import elasticity of wool,wool imported from Uruguay has bright market prospects. In addition,wool imported from Australia has irreplaceable advantage than that from New Zealand.展开更多
针对目前传统安检方法对于车辆底盘表面藏匿的违禁物品的检测效率低、漏检率高、便携性差等不足,设计了一个基于云端的移动式智能车底藏匿物检测系统,通过机器人、网络通信、图像处理及目标检测等技术,实现藏匿物智能化检测。基于SIFT(S...针对目前传统安检方法对于车辆底盘表面藏匿的违禁物品的检测效率低、漏检率高、便携性差等不足,设计了一个基于云端的移动式智能车底藏匿物检测系统,通过机器人、网络通信、图像处理及目标检测等技术,实现藏匿物智能化检测。基于SIFT(Scale-Invariant Feature Transform)算法提取图像特征信息并获取车底局部全景图像,使用YOLOv5(You Only Look Once version 5)深度神经网络模型检测4种车底藏匿物,搭建云数据库存储车辆信息,轮式机器人、上位机、云数据库之间通过TCP/IP(Transmission Control Protocol/Internet Protocol)协议进行通信。经测试,该系统能在特定场景下完成车底藏匿物检测,图像拼接成功率达81.7%,目标检测准确率达83.7%,在车底安检领域具有一定的实用价值。展开更多
交通视频图像目标提取精度低和提取效率低,为此,提出一种基于物联网技术的智能化交通视频图像目标提取方法。采用物联网技术采集交通视频图像,结合对称性检测和灰度验证,识别视频图像前景区域的种子点,根据方向相似性和灰度值连接前景...交通视频图像目标提取精度低和提取效率低,为此,提出一种基于物联网技术的智能化交通视频图像目标提取方法。采用物联网技术采集交通视频图像,结合对称性检测和灰度验证,识别视频图像前景区域的种子点,根据方向相似性和灰度值连接前景种子点,获得视频图像的前景区域,采用模板去噪方法消除前景区域中的噪声;采用YOLOv3(you only look once version 3)模型提取交通视频图像中的目标,引入卡尔曼滤波器跟踪目标,并通过匈牙利匹配提高目标提取精度。实验结果表明,所提方法具有良好的图像处理能力、目标提取精度高、提取效率高。展开更多
The choices of the parameterizations for each component in a microwave emission model have significant effects on the quality of brightness temperature （Tb） sim- ulation. How to reduce the uncertainty in the Tb simu...The choices of the parameterizations for each component in a microwave emission model have significant effects on the quality of brightness temperature （Tb） sim- ulation. How to reduce the uncertainty in the Tb simulation is investigated by adopting a statistical post-processing procedure with the Bayesian model averaging （BMA） ensemble approach. The simulations by the community microwave emission model （CMEM） cou- pled with the community land model version 4.5 （CLM4.5） over China's Mainland are con- ducted by the 24 configurations from four vegetation opacity parameterizations （VOPs）, three soil dielectric constant parameterizations （SDCPs）, and two soil roughness param- eterizations （SRPs）. Compared with the simple arithmetical averaging （SAA） method, the BMA reconstructions have a higher spatial correlation coefficient （larger than 0.99） than the C-band satellite observations of the advanced microwave scanning radiometer on the Earth observing system （AMSR-E） at the vertical polarization. Moreover, the BMA product performs the best among the ensemble members for all vegetation classes, with a mean root-mean-square difference （RMSD） of 4 K and a temporal correlation coefficient of 0.64.展开更多
背景与目的肺部切除术后慢性咳嗽是最常见的并发症之一,严重影响患者术后生活质量,目前国内尚无关于肺部切除术后慢性咳嗽预测模型。因此,本研究旨在探讨肺部切除术后慢性咳嗽相关危险因素,构建预测模型并进行验证。方法回顾性分析2021...背景与目的肺部切除术后慢性咳嗽是最常见的并发症之一,严重影响患者术后生活质量,目前国内尚无关于肺部切除术后慢性咳嗽预测模型。因此,本研究旨在探讨肺部切除术后慢性咳嗽相关危险因素,构建预测模型并进行验证。方法回顾性分析2021年1月至2023年6月于中国科学技术大学附属第一医院接受肺部切除术的499例患者的临床资料和术后咳嗽情况,按7:3随机分配原则分为训练集(n=348)和验证集(n=151),根据训练集患者术后是否慢性咳嗽分为咳嗽组和非咳嗽组。使用中文版莱斯特咳嗽问卷(The Mandarin-Chinese version of Leicester cough questionnare,LCQ-MC)评估术前、术后咳嗽的严重程度及其对患者生活质量的影响,采用咳嗽视觉模拟量表(visual analog scale,VAS)和自拟的数字评分法(numerical rating scale,NRS)评估术后慢性咳嗽,采用单因素和多因素Logistic回归分析独立危险因素和模型构建,受试者工作特征(receiver operator characteristic,ROC)曲线评估模型区分度,校准曲线评估模型的一致性,绘制决策曲线分析(decision curve analysis,DCA)评估模型的临床应用价值。结果多因素Logistic分析筛选出术前用力呼气第1秒呼气量与用力肺活量比(forced expiratory volume in the first second/forced vital capacity,FEV_(1)/FVC)、手术方式、行上纵隔淋巴结清扫、行隆突下淋巴结清扫、术后胸腔闭式引流时间是术后慢性咳嗽的独立危险因素,基于多因素分析结果构建列线图预测模型。ROC曲线下面积为0.954(95%CI:0.930-0.978),最大约登指数所对应的临界值为0.171,此时敏感度为94.7%,特异度为86.6%。Bootstrap法抽样1000次,校准曲线图预测的肺部切除术后慢性咳嗽与实际发生风险高度一致。DCA显示当预测模型概率的预概率为0.1-0.9之间,患者表现为正的净收益。结论肺部切除术后慢性咳嗽严重影响患者生活质量。列线图的可视化展现形式有助于准确预测肺部切除术后慢性咳嗽,为临床决策提供支持。展开更多
The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models(LSM).Particularly in high-altitude regions,choosing appropr...The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models(LSM).Particularly in high-altitude regions,choosing appropriate atmospheric forcing datasets can effectively reduce uncertainties in the LSM simulations.Therefore,this study conducted four offline LSM simulations over the Tibetan Plateau(TP)using the Community Land Model version 4.5(CLM4.5)driven by four state-of-the-art atmospheric forcing datasets.The performances of CRUNCEP(CLM4.5 model default)and three other reanalysis-based atmospheric forcing datasets(i.e.ITPCAS,GSWP3 and WFDEI)in simulating the net primary productivity(NPP)and actual evapotranspiration(ET)were evaluated based on in situ and gridded reference datasets.Compared with in situ observations,simulated results exhibited determination coefficients(R2)ranging from 0.58 to 0.84 and 0.59 to 0.87 for observed NPP and ET,respectively,among which GSWP3 and ITPCAS showed superior performance.At the plateau level,CRUNCEP-based simulations displayed the largest bias compared with the reference NPP and ET.GSWP3-based simulations demonstrated the best performance when comprehensively considering both the magnitudes and change trends of TP-averaged NPP and ET.The simulated ET increase over the TP during 1982-2010 based on ITPCAS was significantly greater than in the other three simulations and reference ET,suggesting that ITPCAS may not be appropriate for studying long-term ET changes over the TP.These results suggest that GSWP3 is recommended for driving CLM4.5 in conducting long-term carbon and water processes simulations over the TP.This study contributes to enhancing the accuracy of LSM in water-carbon simulations over alpine regions.展开更多
基金Supported by the Fundamental Fujian Nature Science (A0440006) and Xiamen Science & Technology Project (3502Z20055028)
文摘A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data： attributes and documents describing each component. The paper discusses the version change relations between a sub-node component and a up-node component in a product structure tree, analyzes the version control system for a static reference and that for a dynamic reference and proposes a product structure model in support of dynamic reference, which is easy to use and contains a complete set of information providing an essential way of data organization for the PDM system.
文摘The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in detail.This chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective model.The construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass regions.It is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)shells.This is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm operation.Although the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard them.The results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.
基金the Scientific Technology Development Project of Heilongjiang(Grant No.WH05A01 and GB05A103)Scientific Technology Development Project of Harbin
文摘Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.
基金supported by the National Natural Science Foundation of China(Grant No.51109071)
文摘Pipe cooling is an effective method of mass concrete temperature control, but its accurate and convenient numerical simulation is still a cumbersome problem. An improved embedded model, considering the water temperature variation along the pipe, was proposed for simulating the temperature field of early-age concrete structures containing cooling pipes. The improved model was verified with an engineering example. Then, the p-version self-adaption algorithm for the improved embedded model was deduced, and the initial values and boundary conditions were examined. Comparison of some numerical samples shows that the proposed model can provide satisfying precision and a higher efficiency. The analysis efficiency can be doubled at the same precision, even for a large-scale element. The p-version algorithm can fit grids of different sizes for the temperature field simulation. The convenience of the proposed algorithm lies in the possibility of locating more pipe segments in one element without the need of so regular a shape as in the explicit model.
基金Industrial Research of National Wool and Csahmere Industry Technology System,China(No.CARS-40-20)
文摘By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal demand system( RSDAIDS) is used to estimate the income and price elasticity of major imported agriculture textile material from the major sources based on the data from 1992 to 2015. The results are shown as follows.( 1) Although the dependency on imported cotton is lower than wool, the fluctuation of cotton import is much more drastic; China's demand for cotton is relatively price elastic with higher expenditure elasticity compared with wool; besides,the existence of complementarity is proved between imported cotton and wool.( 2) According to the import elasticity of cotton,demand for cotton imported from India shows priority over cotton from other sources; demand for cotton imported from America is the most price-sensitive one; substitution among cotton from different sources is weak.( 3) According to the import elasticity of wool,wool imported from Uruguay has bright market prospects. In addition,wool imported from Australia has irreplaceable advantage than that from New Zealand.
文摘针对目前传统安检方法对于车辆底盘表面藏匿的违禁物品的检测效率低、漏检率高、便携性差等不足,设计了一个基于云端的移动式智能车底藏匿物检测系统,通过机器人、网络通信、图像处理及目标检测等技术,实现藏匿物智能化检测。基于SIFT(Scale-Invariant Feature Transform)算法提取图像特征信息并获取车底局部全景图像,使用YOLOv5(You Only Look Once version 5)深度神经网络模型检测4种车底藏匿物,搭建云数据库存储车辆信息,轮式机器人、上位机、云数据库之间通过TCP/IP(Transmission Control Protocol/Internet Protocol)协议进行通信。经测试,该系统能在特定场景下完成车底藏匿物检测,图像拼接成功率达81.7%,目标检测准确率达83.7%,在车底安检领域具有一定的实用价值。
文摘交通视频图像目标提取精度低和提取效率低,为此,提出一种基于物联网技术的智能化交通视频图像目标提取方法。采用物联网技术采集交通视频图像,结合对称性检测和灰度验证,识别视频图像前景区域的种子点,根据方向相似性和灰度值连接前景种子点,获得视频图像的前景区域,采用模板去噪方法消除前景区域中的噪声;采用YOLOv3(you only look once version 3)模型提取交通视频图像中的目标,引入卡尔曼滤波器跟踪目标,并通过匈牙利匹配提高目标提取精度。实验结果表明,所提方法具有良好的图像处理能力、目标提取精度高、提取效率高。
基金Project supported by the China Special Fund for Meteorological Research in the Public Interest(No.GYHY201306045)the National Natural Science Foundation of China(Nos.41305066 and41575096)
文摘The choices of the parameterizations for each component in a microwave emission model have significant effects on the quality of brightness temperature （Tb） sim- ulation. How to reduce the uncertainty in the Tb simulation is investigated by adopting a statistical post-processing procedure with the Bayesian model averaging （BMA） ensemble approach. The simulations by the community microwave emission model （CMEM） cou- pled with the community land model version 4.5 （CLM4.5） over China's Mainland are con- ducted by the 24 configurations from four vegetation opacity parameterizations （VOPs）, three soil dielectric constant parameterizations （SDCPs）, and two soil roughness param- eterizations （SRPs）. Compared with the simple arithmetical averaging （SAA） method, the BMA reconstructions have a higher spatial correlation coefficient （larger than 0.99） than the C-band satellite observations of the advanced microwave scanning radiometer on the Earth observing system （AMSR-E） at the vertical polarization. Moreover, the BMA product performs the best among the ensemble members for all vegetation classes, with a mean root-mean-square difference （RMSD） of 4 K and a temporal correlation coefficient of 0.64.
文摘背景与目的肺部切除术后慢性咳嗽是最常见的并发症之一,严重影响患者术后生活质量,目前国内尚无关于肺部切除术后慢性咳嗽预测模型。因此,本研究旨在探讨肺部切除术后慢性咳嗽相关危险因素,构建预测模型并进行验证。方法回顾性分析2021年1月至2023年6月于中国科学技术大学附属第一医院接受肺部切除术的499例患者的临床资料和术后咳嗽情况,按7:3随机分配原则分为训练集(n=348)和验证集(n=151),根据训练集患者术后是否慢性咳嗽分为咳嗽组和非咳嗽组。使用中文版莱斯特咳嗽问卷(The Mandarin-Chinese version of Leicester cough questionnare,LCQ-MC)评估术前、术后咳嗽的严重程度及其对患者生活质量的影响,采用咳嗽视觉模拟量表(visual analog scale,VAS)和自拟的数字评分法(numerical rating scale,NRS)评估术后慢性咳嗽,采用单因素和多因素Logistic回归分析独立危险因素和模型构建,受试者工作特征(receiver operator characteristic,ROC)曲线评估模型区分度,校准曲线评估模型的一致性,绘制决策曲线分析(decision curve analysis,DCA)评估模型的临床应用价值。结果多因素Logistic分析筛选出术前用力呼气第1秒呼气量与用力肺活量比(forced expiratory volume in the first second/forced vital capacity,FEV_(1)/FVC)、手术方式、行上纵隔淋巴结清扫、行隆突下淋巴结清扫、术后胸腔闭式引流时间是术后慢性咳嗽的独立危险因素,基于多因素分析结果构建列线图预测模型。ROC曲线下面积为0.954(95%CI:0.930-0.978),最大约登指数所对应的临界值为0.171,此时敏感度为94.7%,特异度为86.6%。Bootstrap法抽样1000次,校准曲线图预测的肺部切除术后慢性咳嗽与实际发生风险高度一致。DCA显示当预测模型概率的预概率为0.1-0.9之间,患者表现为正的净收益。结论肺部切除术后慢性咳嗽严重影响患者生活质量。列线图的可视化展现形式有助于准确预测肺部切除术后慢性咳嗽,为临床决策提供支持。
基金supported by the National Key Research and Development Program of China(2022YFC3201702)the National Natural Science Foundation of China(42201146,U2240226)+1 种基金the Science and Technology Project of Sichuan Province(2022NSFSC1001)Fundamental Research Funds for The Central Universities(YJ2021133).
文摘The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models(LSM).Particularly in high-altitude regions,choosing appropriate atmospheric forcing datasets can effectively reduce uncertainties in the LSM simulations.Therefore,this study conducted four offline LSM simulations over the Tibetan Plateau(TP)using the Community Land Model version 4.5(CLM4.5)driven by four state-of-the-art atmospheric forcing datasets.The performances of CRUNCEP(CLM4.5 model default)and three other reanalysis-based atmospheric forcing datasets(i.e.ITPCAS,GSWP3 and WFDEI)in simulating the net primary productivity(NPP)and actual evapotranspiration(ET)were evaluated based on in situ and gridded reference datasets.Compared with in situ observations,simulated results exhibited determination coefficients(R2)ranging from 0.58 to 0.84 and 0.59 to 0.87 for observed NPP and ET,respectively,among which GSWP3 and ITPCAS showed superior performance.At the plateau level,CRUNCEP-based simulations displayed the largest bias compared with the reference NPP and ET.GSWP3-based simulations demonstrated the best performance when comprehensively considering both the magnitudes and change trends of TP-averaged NPP and ET.The simulated ET increase over the TP during 1982-2010 based on ITPCAS was significantly greater than in the other three simulations and reference ET,suggesting that ITPCAS may not be appropriate for studying long-term ET changes over the TP.These results suggest that GSWP3 is recommended for driving CLM4.5 in conducting long-term carbon and water processes simulations over the TP.This study contributes to enhancing the accuracy of LSM in water-carbon simulations over alpine regions.
