If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, ...If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, especially the topographic maps, are discussed due to the replacement of the coordinate systems. Taking the replacement of Xi’an 80 coordinate system by GRS80 for a numerical example, this paper analyzes the changes of latitude, longitude, Gauss plane coordinates of the surface points, as well as the orientation and the length changes between the points on the map, including the changes of map border lines and sheet corner points.展开更多
The concise and informative representation of hyperspectral imagery is achieved via the introduced diffusion geometric coordinates derived from nonlinear dimension reduction maps - diffusion maps. The huge-volume high...The concise and informative representation of hyperspectral imagery is achieved via the introduced diffusion geometric coordinates derived from nonlinear dimension reduction maps - diffusion maps. The huge-volume high- dimensional spectral measurements are organized by the affinity graph where each node in this graph only connects to its local neighbors and each edge in this graph represents local similarity information. By normalizing the affinity graph appropriately, the diffusion operator of the underlying hyperspectral imagery is well-defined, which means that the Markov random walk can be simulated on the hyperspectral imagery. Therefore, the diffusion geometric coordinates, derived from the eigenfunctions and the associated eigenvalues of the diffusion operator, can capture the intrinsic geometric information of the hyperspectral imagery well, which gives more enhanced representation results than traditional linear methods, such as principal component analysis based methods. For large-scale full scene hyperspectral imagery, by exploiting the backbone approach, the computation complexity and the memory requirements are acceptable. Experiments also show that selecting suitable symmetrization normalization techniques while forming the diffusion operator is important to hyperspectral imagery representation.展开更多
This paper presents a numerical model study of the propagation of water waves using the parabolic approximation of the mild slope equation in the orthogonal coordinate system. Two types of coordinate systems are stud...This paper presents a numerical model study of the propagation of water waves using the parabolic approximation of the mild slope equation in the orthogonal coordinate system. Two types of coordinate systems are studied: (a) a general form of orthogonal coordinate system and (b) the conformal system, a special form of orthogonal coordinate system. Two typical examples, namely, expanded breakwaters and a circular channel, are studied to validate the model. First, the examples are studied by use of the general orthogonal coordinates. Then the same examples are computed by use of the conformal system. The computational results show that the conformal coordinate system generally gives better predictions than the general orthogonal system. A numerical technique for generating the conformal grid is combined with the numerical model to improve the practicability of the model. The comparison between the result from the numerical grid system and that from the analytical grid system shows that reliable computational results can be obtained by use of the numerical conformal grid system.展开更多
A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the ex...A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the existing algorithms are almost concentrated on the randomly small-scale network topology, which is not suitable for practical large-scale network environments, because more time is spent on traversing SN and VN, resulting in VN requests congestion. To address this problem, virtual network mapping algorithm is proposed for large-scale network based on small-world characteristic of complex network and network coordinate system. Compared our algorithm with algorithm D-ViNE, experimental results show that our algorithm improves the overall performance.展开更多
Children with Developmental Coordination Disorder (DCD) often seem to possess a narrow repertoire of cognitive strategies. In particular, they have difficulties in learning and internalizing the rules and strategies t...Children with Developmental Coordination Disorder (DCD) often seem to possess a narrow repertoire of cognitive strategies. In particular, they have difficulties in learning and internalizing the rules and strategies that other people intuitively use to approach common everyday problems. As a result, they often appear to have organizational, planning, memory and learning difficulties. The article proposes using a Concept Map (CM) as a visual strategy to facilitate interaction between a child with DCD, his/her family and therapist, as reflected in Client Centred and cognitive approaches. The CM is used as a method of assisting the child to identify, develop and utilize cognitive strategies in order to manage daily tasks effectively, as a tool in organizing his own therapy and in order to encourage participation. A demonstration of the concept mapping usefulness is brought by a case report. Further uses of concept mapping as a useful strategy within the framework of intervention remain to be studied.展开更多
Deriving reaction coordinates for the characterization of chemical reactions has long been a demanding task.In our previous work[ACS Cent.Sci.3,407(2017)],the reaction coordinate of a(retro-)Claisen rearrangement in a...Deriving reaction coordinates for the characterization of chemical reactions has long been a demanding task.In our previous work[ACS Cent.Sci.3,407(2017)],the reaction coordinate of a(retro-)Claisen rearrangement in aqueous solution optimized through a Bayesian measure,a linear combination of bond lengths formation and breakage,was judged to be optimal among all trails.Here,considering the nonlinearity of the transition state,we use isometric mapping and locally linear embedding to obtain one reaction coordinate which is composed of a few collective variables.With these methods,we find a more reasonable and powerful one-dimensional reaction coordinate,which can well describe the reaction progression.To explore the reaction mechanism,we analyze the contribution of intrinsic molecular properties and the solventsolute interactions to the nonlinear reaction coordinate.Furthermore,another coordinate is identified to characterize the heterogeneity of reaction mechanisms.展开更多
Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period...Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period.In this paper,the waveform of the transient current component is transformed into multiple intersecting curves in an alternative coordinate system,utilizing the principle of coordinate mapping.The internal and external faults are identified by determining the range of angles between the current waveforms and the time axis based on the intersecting regions of the curves.Subsequently,a unit protection scheme based on the transient current coordinate mapping interval is proposed.Finally,a modular multi-level converter-high voltage direct current(MMC-HVDC)system is built using PSCAD/EMTDC to validate the proposed scheme.The simulation results show that the proposed protection scheme is insensitive to factors such as current fluctuations caused by noise and distributed capacitive currents.In addition,it shows high robustness against fault resistance.展开更多
Spatial data have become indispensable across various disciplines and provide crucial insights.These data are associated with coordinates and different coordinate systems.However,the diversity of geospatial data forma...Spatial data have become indispensable across various disciplines and provide crucial insights.These data are associated with coordinates and different coordinate systems.However,the diversity of geospatial data formats and disparate coordinate systems present challenges in harmonizing them for analysis.This study addresses the pressing need for an improved approach to the batch transformation of commonly used coordinate systems in Sri Lanka.First,we examine different coordinate transformation systems and identify their limitations.Subsequently,we present a comprehensive procedure for seamless coordinate transformations between various systems.To demonstrate the practical applications of our approach,we have developed a user-friendly desktop application capable of simultaneously converting input coordinates into multiple systems.This application streamlines the process for users unfamiliar with sophisticated geographic information system(GIS)applications and datum transformations.We validate the output coordinates transformed using our application by comparing them with those obtained from established applications such as ArcGIS and epsg.io.The results,which have been assessed based on the root mean squared error(RMSE)and mean absolute error(MAE),indicate high levels of accuracy,with a maximum RMSE of approximately 0.013 and a maximum MAE of approximately 0.008.A performance evaluation reveals that our approach is exceptionally efficient,outperforming ArcGIS and epsg.io by 40x and 60x,respectively.Moreover,the proposed pipeline holds potential as an infrastructure for developing web applications,mobile applications,and plugins for popular GIS platforms such as ArcGIS and QGIS.展开更多
The capabilities of GIS for constructing a digital elevation model of a mountainous area and visualizing a spatial image of the terrain are given in this paper.Graphic,digital data and topographic maps,which are the m...The capabilities of GIS for constructing a digital elevation model of a mountainous area and visualizing a spatial image of the terrain are given in this paper.Graphic,digital data and topographic maps,which are the main sources for GIS,are described.The methods of vectorization of isolines and the requirements for technical means of processing graphic materials are presented in detail.The advantages and disadvantages of the DEM of a mountainous region are shown here.Segmentation methods using an interpolation polynomial are described in detail.A DEM of the mountainous area where the border between the republics runs was constructed in 2D and 3D formats using the GIS Panorama.Reducing the chord length when segmenting isolines on topographic maps leads to more accurate DEM construction.A vertical profile of a mountainous area with a visibility zone between two points was constructed.It is expected that the improved latitude,longitude and altitude parameters of the topographic map will be used to form a regional geodetic network and geospatial analysis of mountain ranges.It is proposed to use not only satellite data,but also classical geodetic networks and maps.It is recommended to use satellite and aerial photography to clarify the topographic and geodetic support of the studied area.展开更多
Global Mapper支持多种格式的光栅、高程、矢量数据的读取与输出,并内置多种坐标投影方式。尝试挖掘其支持多种数据格式、多种投影模式的功能,快速实现测绘图形数据的转换。通过设置当前工作空间的坐标投影模式,然后打开任何其支持的、...Global Mapper支持多种格式的光栅、高程、矢量数据的读取与输出,并内置多种坐标投影方式。尝试挖掘其支持多种数据格式、多种投影模式的功能,快速实现测绘图形数据的转换。通过设置当前工作空间的坐标投影模式,然后打开任何其支持的、含有坐标投影信息的数据,所有数据均自动转换成当前的投影模式,最后将文件输出(另存为)为所需的格式,即可快速完成数据转换。转换的内容主要包括不同格式的DTM(Digital Terrain Model,数字地面模型)数据转换、相同格式但不同坐标投影之间的相互转换,以及卫星影像配准等。展开更多
文摘If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, especially the topographic maps, are discussed due to the replacement of the coordinate systems. Taking the replacement of Xi’an 80 coordinate system by GRS80 for a numerical example, this paper analyzes the changes of latitude, longitude, Gauss plane coordinates of the surface points, as well as the orientation and the length changes between the points on the map, including the changes of map border lines and sheet corner points.
基金The National Key Technologies R & D Program during the 11th Five-Year Plan Period (No.2006BAB15B01)
文摘The concise and informative representation of hyperspectral imagery is achieved via the introduced diffusion geometric coordinates derived from nonlinear dimension reduction maps - diffusion maps. The huge-volume high- dimensional spectral measurements are organized by the affinity graph where each node in this graph only connects to its local neighbors and each edge in this graph represents local similarity information. By normalizing the affinity graph appropriately, the diffusion operator of the underlying hyperspectral imagery is well-defined, which means that the Markov random walk can be simulated on the hyperspectral imagery. Therefore, the diffusion geometric coordinates, derived from the eigenfunctions and the associated eigenvalues of the diffusion operator, can capture the intrinsic geometric information of the hyperspectral imagery well, which gives more enhanced representation results than traditional linear methods, such as principal component analysis based methods. For large-scale full scene hyperspectral imagery, by exploiting the backbone approach, the computation complexity and the memory requirements are acceptable. Experiments also show that selecting suitable symmetrization normalization techniques while forming the diffusion operator is important to hyperspectral imagery representation.
文摘This paper presents a numerical model study of the propagation of water waves using the parabolic approximation of the mild slope equation in the orthogonal coordinate system. Two types of coordinate systems are studied: (a) a general form of orthogonal coordinate system and (b) the conformal system, a special form of orthogonal coordinate system. Two typical examples, namely, expanded breakwaters and a circular channel, are studied to validate the model. First, the examples are studied by use of the general orthogonal coordinates. Then the same examples are computed by use of the conformal system. The computational results show that the conformal coordinate system generally gives better predictions than the general orthogonal system. A numerical technique for generating the conformal grid is combined with the numerical model to improve the practicability of the model. The comparison between the result from the numerical grid system and that from the analytical grid system shows that reliable computational results can be obtained by use of the numerical conformal grid system.
基金Sponsored by the Funds for Creative Research Groups of China(Grant No. 60821001)National Natural Science Foundation of China(Grant No.60973108 and 60902050)973 Project of China (Grant No.2007CB310703)
文摘A major challenge of network virtualization is the virtual network resource allocation problem that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. However, the existing algorithms are almost concentrated on the randomly small-scale network topology, which is not suitable for practical large-scale network environments, because more time is spent on traversing SN and VN, resulting in VN requests congestion. To address this problem, virtual network mapping algorithm is proposed for large-scale network based on small-world characteristic of complex network and network coordinate system. Compared our algorithm with algorithm D-ViNE, experimental results show that our algorithm improves the overall performance.
文摘Children with Developmental Coordination Disorder (DCD) often seem to possess a narrow repertoire of cognitive strategies. In particular, they have difficulties in learning and internalizing the rules and strategies that other people intuitively use to approach common everyday problems. As a result, they often appear to have organizational, planning, memory and learning difficulties. The article proposes using a Concept Map (CM) as a visual strategy to facilitate interaction between a child with DCD, his/her family and therapist, as reflected in Client Centred and cognitive approaches. The CM is used as a method of assisting the child to identify, develop and utilize cognitive strategies in order to manage daily tasks effectively, as a tool in organizing his own therapy and in order to encourage participation. A demonstration of the concept mapping usefulness is brought by a case report. Further uses of concept mapping as a useful strategy within the framework of intervention remain to be studied.
基金supported by the National Nature Science Foundation of China(No.21927901 and No.92053202 to Yi Qin Gao)Zhen Zhang is supported by the Education Department of Hebei Province(QN2018308)+1 种基金Post-doctoral Foundation Project of Tangshan Normal University(2018A03)the Nature Science Foundation of Hebei Province of China(E2019105073)。
文摘Deriving reaction coordinates for the characterization of chemical reactions has long been a demanding task.In our previous work[ACS Cent.Sci.3,407(2017)],the reaction coordinate of a(retro-)Claisen rearrangement in aqueous solution optimized through a Bayesian measure,a linear combination of bond lengths formation and breakage,was judged to be optimal among all trails.Here,considering the nonlinearity of the transition state,we use isometric mapping and locally linear embedding to obtain one reaction coordinate which is composed of a few collective variables.With these methods,we find a more reasonable and powerful one-dimensional reaction coordinate,which can well describe the reaction progression.To explore the reaction mechanism,we analyze the contribution of intrinsic molecular properties and the solventsolute interactions to the nonlinear reaction coordinate.Furthermore,another coordinate is identified to characterize the heterogeneity of reaction mechanisms.
基金supported by the Tianshan Talent Training Program(No.2022TSYCLJ0019)the National Key R&D Program of China(No.2021YFB1507000)+1 种基金the Excellent Doctoral Research and Innovation Project of Xinjiang University(No.XJU2022BS094)the Natural Science Foundation of Xinjiang Uygur Autonomous Region Sponsored Programs(No.2022D01C662).
文摘Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period.In this paper,the waveform of the transient current component is transformed into multiple intersecting curves in an alternative coordinate system,utilizing the principle of coordinate mapping.The internal and external faults are identified by determining the range of angles between the current waveforms and the time axis based on the intersecting regions of the curves.Subsequently,a unit protection scheme based on the transient current coordinate mapping interval is proposed.Finally,a modular multi-level converter-high voltage direct current(MMC-HVDC)system is built using PSCAD/EMTDC to validate the proposed scheme.The simulation results show that the proposed protection scheme is insensitive to factors such as current fluctuations caused by noise and distributed capacitive currents.In addition,it shows high robustness against fault resistance.
文摘Spatial data have become indispensable across various disciplines and provide crucial insights.These data are associated with coordinates and different coordinate systems.However,the diversity of geospatial data formats and disparate coordinate systems present challenges in harmonizing them for analysis.This study addresses the pressing need for an improved approach to the batch transformation of commonly used coordinate systems in Sri Lanka.First,we examine different coordinate transformation systems and identify their limitations.Subsequently,we present a comprehensive procedure for seamless coordinate transformations between various systems.To demonstrate the practical applications of our approach,we have developed a user-friendly desktop application capable of simultaneously converting input coordinates into multiple systems.This application streamlines the process for users unfamiliar with sophisticated geographic information system(GIS)applications and datum transformations.We validate the output coordinates transformed using our application by comparing them with those obtained from established applications such as ArcGIS and epsg.io.The results,which have been assessed based on the root mean squared error(RMSE)and mean absolute error(MAE),indicate high levels of accuracy,with a maximum RMSE of approximately 0.013 and a maximum MAE of approximately 0.008.A performance evaluation reveals that our approach is exceptionally efficient,outperforming ArcGIS and epsg.io by 40x and 60x,respectively.Moreover,the proposed pipeline holds potential as an infrastructure for developing web applications,mobile applications,and plugins for popular GIS platforms such as ArcGIS and QGIS.
文摘The capabilities of GIS for constructing a digital elevation model of a mountainous area and visualizing a spatial image of the terrain are given in this paper.Graphic,digital data and topographic maps,which are the main sources for GIS,are described.The methods of vectorization of isolines and the requirements for technical means of processing graphic materials are presented in detail.The advantages and disadvantages of the DEM of a mountainous region are shown here.Segmentation methods using an interpolation polynomial are described in detail.A DEM of the mountainous area where the border between the republics runs was constructed in 2D and 3D formats using the GIS Panorama.Reducing the chord length when segmenting isolines on topographic maps leads to more accurate DEM construction.A vertical profile of a mountainous area with a visibility zone between two points was constructed.It is expected that the improved latitude,longitude and altitude parameters of the topographic map will be used to form a regional geodetic network and geospatial analysis of mountain ranges.It is proposed to use not only satellite data,but also classical geodetic networks and maps.It is recommended to use satellite and aerial photography to clarify the topographic and geodetic support of the studied area.
