The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline （NU...The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline （NURBS） entity. According to the characteristics of NURBS, a novel data structure, named NURBS material data structure, is proposed, in which the geometrical coordinates, weights and material coordinates of NURBS heterogene- ous objects can be represented simultaneously. Based on this data structure, both direct representation method and inverse construction method of heterogeneous NURBS objects are introduced. In the direct representation method, three forms of NURBS heterogeneous objects are introduced by giving the geometry and material information of con- trol points, among which the homogeneous coordinates form is employed for its brevity and easy programming. In the inverse construction method, continuous heterogeneous curves and surfaces can he obtained by interpolating discrete points and curves with specified material information. Some examples are given to show the effectiveness of the pro- posed methods.展开更多
Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome t...Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.展开更多
In this paper,the(0.1)-form heat kernel of a complex projective space of dimensions n is constructed cxplicitely.As an application of the(0.1)-form heat kernel,the(0.1)type Green Form of CP~
A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea...A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea surface temperature(SST),the zonally averaged seasonal cycle of SST,the variability of the sea level anomaly(SLA),the zonally and meridionally averaged temperature and salinity,and the equatorial undercurrent.It is found that the simulated seasonal cycle of SST is 0.2–0.8 stronger than observed at midlatitudes.The modeled SST is 0.29°C warmer than the observed for the global ocean.the structure of the subsurface temperature and salinity is similar to the observed.moreover,the variability of SLA exhibits the same pattern as observed.The modeled equatorial undercurrent in the pacific ocean is weaker than observed,but stronger than the ecco reanalysis product.overall,the model can reproduce the large-scale ocean states,and is suitable for analyses seeking to better understand the dynamics and thermodynamics of the upper ocean,as well as ocean variability.展开更多
基金Supported by National Natural Science Foundation of China (No. 60973079)Natural Science Foundation of Hebei Province (No. E2006000039)
文摘The representation method of heterogeneous material information is one of the key technologies of heterogeneous object modeling, but almost all the existing methods cannot represent non-uniform rational B-spline （NURBS） entity. According to the characteristics of NURBS, a novel data structure, named NURBS material data structure, is proposed, in which the geometrical coordinates, weights and material coordinates of NURBS heterogene- ous objects can be represented simultaneously. Based on this data structure, both direct representation method and inverse construction method of heterogeneous NURBS objects are introduced. In the direct representation method, three forms of NURBS heterogeneous objects are introduced by giving the geometry and material information of con- trol points, among which the homogeneous coordinates form is employed for its brevity and easy programming. In the inverse construction method, continuous heterogeneous curves and surfaces can he obtained by interpolating discrete points and curves with specified material information. Some examples are given to show the effectiveness of the pro- posed methods.
基金State Administration of Science,Technology and Industry for the National Defense(No.JSJL2014206B001)。
文摘Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.
基金This subject supported by NSF of ChinaThis subject supported by the Henan Fundations of Scientific Committee.
文摘In this paper,the(0.1)-form heat kernel of a complex projective space of dimensions n is constructed cxplicitely.As an application of the(0.1)-form heat kernel,the(0.1)type Green Form of CP~
基金supported by the National Key R&D Program of China [Grant No.2016YFC1401705]the National Natural Science Foundation of China [Grant Nos.41176015 and41776041]+2 种基金the Chinese Academy Sciences Project ‘Western Pacific Ocean System:Structure,Dynamics and Consequences’[Grant No.XDA11010203]confidencial military project [Grant No.315030401]the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [Project No.LTO1501]
文摘A historical run(1993–2014)of a global,eddy-permitting,hybrid coordinate ocean model(HYCOM)is evaluated against observations.The authors evaluate several metrics in the model,including the spatial distribution of sea surface temperature(SST),the zonally averaged seasonal cycle of SST,the variability of the sea level anomaly(SLA),the zonally and meridionally averaged temperature and salinity,and the equatorial undercurrent.It is found that the simulated seasonal cycle of SST is 0.2–0.8 stronger than observed at midlatitudes.The modeled SST is 0.29°C warmer than the observed for the global ocean.the structure of the subsurface temperature and salinity is similar to the observed.moreover,the variability of SLA exhibits the same pattern as observed.The modeled equatorial undercurrent in the pacific ocean is weaker than observed,but stronger than the ecco reanalysis product.overall,the model can reproduce the large-scale ocean states,and is suitable for analyses seeking to better understand the dynamics and thermodynamics of the upper ocean,as well as ocean variability.
