Collision detection is an important component in simulation applications which are based on virtual geographic information system(VGIS).In this paper,an effective collision detection algorithm for multiple objects in ...Collision detection is an important component in simulation applications which are based on virtual geographic information system(VGIS).In this paper,an effective collision detection algorithm for multiple objects in VGIS,VGISCOLLIDE,is presented.The algorithm firstly integrates existing quadtree,which is the global hierarchical structure of VGIS,with axis-aligned bounding box of object to perform the broad-phase of collision detection.After that,exact collision detection between two objects which have passed the broad-phase of collision detection is performed.The algorithm makes no assumption about input primitives or object’s motion and is directly applicable to all triangulated models.It can be applicable to both rigid and deformable objects without preprocessing.The performance of the algorithm has been demonstrated in several environments consisting of a high number of objects with hundreds of thousands of triangles.展开更多
With the proposition of the Digital Earth(DE)concept,Virtual Geographic Information System(VGIS)has started to play the role of a Digital Earth prototype system.Many core problems involved in VGIS,such as out-of-core ...With the proposition of the Digital Earth(DE)concept,Virtual Geographic Information System(VGIS)has started to play the role of a Digital Earth prototype system.Many core problems involved in VGIS,such as out-of-core management and interactive rendering of very large scale terrain and image data,have been well studied in the past decades.However,the jitter problem,a common problem in VGIS that often causes annoying visual artefacts and deteriorates the output image quality,draws little attention.In this paper,after an intensive analysis of the jitter problem,a comprehensive framework is proposed to address such a problem while accounting for the characteristics of different data types in VGIS,such as terrain or ocean mesh data,vector data and 3-D model data.Specifically,this framework provides an improved dynamic local coordinate system(DLCS)method for terrain or ocean mesh data.For vector data,the framework provides a simple and effective multiple local coordinate systems(MLCS)method.The framework provides a MLCS method for 3-D model data making full use of the existing local coordinate system of the model.The advantages of the proposed methods over current approaches are analysed and highlighted through case studies involving large GIS datasets.展开更多
HMA2(heavy metal ATPase 2)plays a crucial role in extracellular and intracellular Zn^(2+)transport across biomembranes,maintaining ion homeostasis,and playing an important role in the normal physiological metabolism,g...HMA2(heavy metal ATPase 2)plays a crucial role in extracellular and intracellular Zn^(2+)transport across biomembranes,maintaining ion homeostasis,and playing an important role in the normal physiological metabolism,growth,and development of plants.In our study,a novel HMA2 gene,named MaHMA2,was isolated and cloned from white mulberry(Morus alba L.).The gene sequence obtained was 1,342 bp long,with an open reading frame of 1,194 bp,encoding a protein of 397 amino acids,with a predicted molecular mass of 42.852 kD and an isoelectric point of 7.53.This protein belonged to the PIB-type ATPase transport protein family.We analyzed the expression of the MaHMA2 gene by quantitative real-time PCR.The results showed that the level of MaHMA2 gene expression decreased to a Zn concentration of 800 mg/kg.Malondialdehyde and proline levels increased and responded to increasing Zn when the MaHMA2 gene was silenced,whereas the activities of peroxidase and superoxide dismutase tended to increase in response to increasing Zn^(2+)ion stress concentrations but were lower in the gene-silenced plants.These findings suggested that the MaHMA2 gene played an active role in the tolerance response of mulberry to Zn stress.展开更多
基金supported by a Grant from the National High Technology Research and Development Program of China(863 Programme)(No.2009AA12Z331).
文摘Collision detection is an important component in simulation applications which are based on virtual geographic information system(VGIS).In this paper,an effective collision detection algorithm for multiple objects in VGIS,VGISCOLLIDE,is presented.The algorithm firstly integrates existing quadtree,which is the global hierarchical structure of VGIS,with axis-aligned bounding box of object to perform the broad-phase of collision detection.After that,exact collision detection between two objects which have passed the broad-phase of collision detection is performed.The algorithm makes no assumption about input primitives or object’s motion and is directly applicable to all triangulated models.It can be applicable to both rigid and deformable objects without preprocessing.The performance of the algorithm has been demonstrated in several environments consisting of a high number of objects with hundreds of thousands of triangles.
基金by the National High Technology Research and Development Program of China(863 Program)(No.2009AA12Z331)and the National Natural Science Foundation of China(No.60972052)supported by the Young Researcher Grant of National Astronomical Observatories,Chinese Academy of Sciences.
文摘With the proposition of the Digital Earth(DE)concept,Virtual Geographic Information System(VGIS)has started to play the role of a Digital Earth prototype system.Many core problems involved in VGIS,such as out-of-core management and interactive rendering of very large scale terrain and image data,have been well studied in the past decades.However,the jitter problem,a common problem in VGIS that often causes annoying visual artefacts and deteriorates the output image quality,draws little attention.In this paper,after an intensive analysis of the jitter problem,a comprehensive framework is proposed to address such a problem while accounting for the characteristics of different data types in VGIS,such as terrain or ocean mesh data,vector data and 3-D model data.Specifically,this framework provides an improved dynamic local coordinate system(DLCS)method for terrain or ocean mesh data.For vector data,the framework provides a simple and effective multiple local coordinate systems(MLCS)method.The framework provides a MLCS method for 3-D model data making full use of the existing local coordinate system of the model.The advantages of the proposed methods over current approaches are analysed and highlighted through case studies involving large GIS datasets.
基金This work was supported by the China Agriculture Research System of MOF and MARA,National Key R&D Program of China,the key projects of International Scientific and Technological Innovation Cooperation(Grant No.2021YFE0111100)the Guangxi Innovation-Driven Development Project(Grant No.AA19182012-2)the Zhenjiang Science and Technology Support Project(Grant No.GJ2021015).
文摘HMA2(heavy metal ATPase 2)plays a crucial role in extracellular and intracellular Zn^(2+)transport across biomembranes,maintaining ion homeostasis,and playing an important role in the normal physiological metabolism,growth,and development of plants.In our study,a novel HMA2 gene,named MaHMA2,was isolated and cloned from white mulberry(Morus alba L.).The gene sequence obtained was 1,342 bp long,with an open reading frame of 1,194 bp,encoding a protein of 397 amino acids,with a predicted molecular mass of 42.852 kD and an isoelectric point of 7.53.This protein belonged to the PIB-type ATPase transport protein family.We analyzed the expression of the MaHMA2 gene by quantitative real-time PCR.The results showed that the level of MaHMA2 gene expression decreased to a Zn concentration of 800 mg/kg.Malondialdehyde and proline levels increased and responded to increasing Zn when the MaHMA2 gene was silenced,whereas the activities of peroxidase and superoxide dismutase tended to increase in response to increasing Zn^(2+)ion stress concentrations but were lower in the gene-silenced plants.These findings suggested that the MaHMA2 gene played an active role in the tolerance response of mulberry to Zn stress.
