目的探讨MR 3D CUBE技术对膝关节前交叉韧带损伤的诊断价值。材料与方法对膝关节损伤拟行手术病人术前行MR扫描,以关节镜所见为参考依据,对80例患者86个膝关节行常规MRI序列扫描后加扫3D CUBE T2WI序列,运用AW4.4工作站对3D图像进行后...目的探讨MR 3D CUBE技术对膝关节前交叉韧带损伤的诊断价值。材料与方法对膝关节损伤拟行手术病人术前行MR扫描,以关节镜所见为参考依据,对80例患者86个膝关节行常规MRI序列扫描后加扫3D CUBE T2WI序列,运用AW4.4工作站对3D图像进行后处理重建。分别与关节镜术后结果进行对比分析,计算常规MRI序列及3D CUBE技术在诊断前交叉韧带损伤中的特异度、灵敏度及准确度。结果 3D CUBE T2WI序列在诊断前交叉韧带损伤特异度89%、灵敏度95%、准确度84%;常规MRI序列在诊断前交叉韧带损伤的特异度68%、灵敏度83%、准确度51%。结论 3DCUBE序列扫描时间短,图像可多角度任意旋转,可显示完整前交叉韧带,对前交叉韧带损伤的特异度、灵敏度及准确度较常规MRI序列高。展开更多
Understanding the interactions between humans and nature in the Anthropocene is central to the quest for both human wellbeing and global sustainability.However,the time-space compression,long range interactions,and re...Understanding the interactions between humans and nature in the Anthropocene is central to the quest for both human wellbeing and global sustainability.However,the time-space compression,long range interactions,and reconstruction of socio-economic structures at the global scale all pose great challenges to the traditional analytical frameworks of human-nature systems.In this paper,we extend the connotation of coupled human and natural systems(CHANS)and their four dimensions—space,time,appearance,and organization,and propose a novel framework:“Coupled Human and Natural Cube”(CHNC)to explain the coupling mechanism between humans and the natural environment.Our proposition is inspired by theories based on the human-earth areal system,telecoupling framework,planetary urbanization,and perspectives from complexity science.We systematically introduce the concept,connotation,evolution rules,and analytical dimensions of the CHNC.Notably there exist various“coupling lines”in the CHNC,connecting different systems and elements at multiple scales and forming a large,nested,interconnected,organic system.The rotation of the CHNC represents spatiotemporal nonlinear fluctuations in CHANS in different regions.As a system continually exchanges energy with the environment,a critical phase transition occurs when fluctuations reach a certain threshold,leading to emergent behavior of the system.The CHNC has four dimensions—pericoupling and telecoupling,syncoupling and lagcoupling,apparent coupling and hidden coupling,and intra-organization coupling and inter-organizational coupling.We mainly focus on the theoretical connotation,research methods,and typical cases of telecoupling,lagcoupling,hidden coupling,and inter-organizational coupling,and put forward a human-nature coupling matrix to integrate multiple dimensions.In summary,the CHNC provides a more comprehensive and systematic research paradigm for understanding the evolution and coupling mechanism of the human-nature system,which expands the analytical dimension of CHA展开更多
Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respec...Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respectively. With the Hausdorff-metric, they are topological spaces. In this paper, we prove that, if X is an infinite compact metric space with a dense set of isolated points, then (↓USCC(X), ↓CC(X)) ≈ (Q, c 0 ∪ (Q Σ)), i.e., there is a homeomorphism h:↓USCC(X) → Q such that h(↓CC(X)) = c 0 ∪ (Q Σ), where Q = [?1,1]ω, Σ = {(x n ) n∈? ∈ Q: sup|x n | < 1} and c 0 = {(x n ) n∈? ∈ Σ: lim n→+∞ x n = 0}. Combining this statement with a result in our previous paper, we have $$ ( \downarrow USCC(X), \downarrow CC(X)) \approx \left\{ \begin{gathered} (Q,c_0 \cup (Q\backslash \Sigma )), if the set of isolanted points is dense in X, \hfill \\ (Q,c_0 ),otherwise, \hfill \\ \end{gathered} \right. $$ if X is an infinite compact metric space. We also prove that, for a metric space X, (↓USCC(X), ↓CC(X)) ≈ (Σ, c 0) if and only if X is non-compact, locally compact, non-discrete and separable.展开更多
Pressures on natural resources are increasing and a number of challenges need to be overcome to meet the needs of a growing population in a period of environmental variability.Some of these environmental issues can be...Pressures on natural resources are increasing and a number of challenges need to be overcome to meet the needs of a growing population in a period of environmental variability.Some of these environmental issues can be monitored using remotely sensed Earth Observations(EO)data that are increasingly available from a number of freely and openly accessible repositories.However,the full information potential of EO data has not been yet realized.They remain still underutilized mainly because of their complexity,increasing volume,and the lack of efficient processing capabilities.EO Data Cubes(DC)are a new paradigm aiming to realize the full potential of EO data by lowering the barriers caused by these Big data challenges and providing access to large spatio-temporal data in an analysis ready form.Systematic and regular provision of Analysis Ready Data(ARD)will significantly reduce the burden on EO data users.Nevertheless,ARD are not commonly produced by data providers and therefore getting uniform and consistent ARD remains a challenging task.This paper presents an approach to enable rapid data access and pre-processing to generate ARD using interoperable services chains.The approach has been tested and validated generating Landsat ARD while building the Swiss Data Cube.展开更多
本文介绍了采用三个服务器并行处理方式的小型 OL AP系统 .此系统占用最小的存储空间、具有最短的处理时间和最快查询速度、除有效地解决了传统系统中请求叶子数据聚合的查询速度慢的问题外 ,同时还满足了系统的可靠性和不间断运行数据...本文介绍了采用三个服务器并行处理方式的小型 OL AP系统 .此系统占用最小的存储空间、具有最短的处理时间和最快查询速度、除有效地解决了传统系统中请求叶子数据聚合的查询速度慢的问题外 ,同时还满足了系统的可靠性和不间断运行数据更新的要求 .文中详细地描述了系统的结构、原理、性能。展开更多
文摘目的探讨MR 3D CUBE技术对膝关节前交叉韧带损伤的诊断价值。材料与方法对膝关节损伤拟行手术病人术前行MR扫描,以关节镜所见为参考依据,对80例患者86个膝关节行常规MRI序列扫描后加扫3D CUBE T2WI序列,运用AW4.4工作站对3D图像进行后处理重建。分别与关节镜术后结果进行对比分析,计算常规MRI序列及3D CUBE技术在诊断前交叉韧带损伤中的特异度、灵敏度及准确度。结果 3D CUBE T2WI序列在诊断前交叉韧带损伤特异度89%、灵敏度95%、准确度84%;常规MRI序列在诊断前交叉韧带损伤的特异度68%、灵敏度83%、准确度51%。结论 3DCUBE序列扫描时间短,图像可多角度任意旋转,可显示完整前交叉韧带,对前交叉韧带损伤的特异度、灵敏度及准确度较常规MRI序列高。
基金Program of the National Natural Science Foundation of China,No.41590842,No.41801164China Postdoctoral Science Foundation,No.2018M630196。
文摘Understanding the interactions between humans and nature in the Anthropocene is central to the quest for both human wellbeing and global sustainability.However,the time-space compression,long range interactions,and reconstruction of socio-economic structures at the global scale all pose great challenges to the traditional analytical frameworks of human-nature systems.In this paper,we extend the connotation of coupled human and natural systems(CHANS)and their four dimensions—space,time,appearance,and organization,and propose a novel framework:“Coupled Human and Natural Cube”(CHNC)to explain the coupling mechanism between humans and the natural environment.Our proposition is inspired by theories based on the human-earth areal system,telecoupling framework,planetary urbanization,and perspectives from complexity science.We systematically introduce the concept,connotation,evolution rules,and analytical dimensions of the CHNC.Notably there exist various“coupling lines”in the CHNC,connecting different systems and elements at multiple scales and forming a large,nested,interconnected,organic system.The rotation of the CHNC represents spatiotemporal nonlinear fluctuations in CHANS in different regions.As a system continually exchanges energy with the environment,a critical phase transition occurs when fluctuations reach a certain threshold,leading to emergent behavior of the system.The CHNC has four dimensions—pericoupling and telecoupling,syncoupling and lagcoupling,apparent coupling and hidden coupling,and intra-organization coupling and inter-organizational coupling.We mainly focus on the theoretical connotation,research methods,and typical cases of telecoupling,lagcoupling,hidden coupling,and inter-organizational coupling,and put forward a human-nature coupling matrix to integrate multiple dimensions.In summary,the CHNC provides a more comprehensive and systematic research paradigm for understanding the evolution and coupling mechanism of the human-nature system,which expands the analytical dimension of CHA
基金supported by National Natural Science Foundation of China (Grant No. 10471084)
文摘Let (X, ρ) be a metric space and ↓USCC(X) and ↓CC(X) be the families of the regions below all upper semi-continuous compact-supported maps and below all continuous compact-supported maps from X to I = [0,1], respectively. With the Hausdorff-metric, they are topological spaces. In this paper, we prove that, if X is an infinite compact metric space with a dense set of isolated points, then (↓USCC(X), ↓CC(X)) ≈ (Q, c 0 ∪ (Q Σ)), i.e., there is a homeomorphism h:↓USCC(X) → Q such that h(↓CC(X)) = c 0 ∪ (Q Σ), where Q = [?1,1]ω, Σ = {(x n ) n∈? ∈ Q: sup|x n | < 1} and c 0 = {(x n ) n∈? ∈ Σ: lim n→+∞ x n = 0}. Combining this statement with a result in our previous paper, we have $$ ( \downarrow USCC(X), \downarrow CC(X)) \approx \left\{ \begin{gathered} (Q,c_0 \cup (Q\backslash \Sigma )), if the set of isolanted points is dense in X, \hfill \\ (Q,c_0 ),otherwise, \hfill \\ \end{gathered} \right. $$ if X is an infinite compact metric space. We also prove that, for a metric space X, (↓USCC(X), ↓CC(X)) ≈ (Σ, c 0) if and only if X is non-compact, locally compact, non-discrete and separable.
基金The authors would like to thank the Swiss Federal Office for the Environment(FOEN)for their financial support to the Swiss Data Cube.
文摘Pressures on natural resources are increasing and a number of challenges need to be overcome to meet the needs of a growing population in a period of environmental variability.Some of these environmental issues can be monitored using remotely sensed Earth Observations(EO)data that are increasingly available from a number of freely and openly accessible repositories.However,the full information potential of EO data has not been yet realized.They remain still underutilized mainly because of their complexity,increasing volume,and the lack of efficient processing capabilities.EO Data Cubes(DC)are a new paradigm aiming to realize the full potential of EO data by lowering the barriers caused by these Big data challenges and providing access to large spatio-temporal data in an analysis ready form.Systematic and regular provision of Analysis Ready Data(ARD)will significantly reduce the burden on EO data users.Nevertheless,ARD are not commonly produced by data providers and therefore getting uniform and consistent ARD remains a challenging task.This paper presents an approach to enable rapid data access and pre-processing to generate ARD using interoperable services chains.The approach has been tested and validated generating Landsat ARD while building the Swiss Data Cube.
