Surface convexity is a key issue in computer aided geometric design, which is widely applied in geometric modeling field, such as physical models, industrial design, automatic manufacturing, etc. In this paper, a suff...Surface convexity is a key issue in computer aided geometric design, which is widely applied in geometric modeling field, such as physical models, industrial design, automatic manufacturing, etc. In this paper, a sufficient convexity condition of the parametric Bézier surface over rectangles is proposed, which is firstly considered as a sufficient convexity condition for the Bézier control grid. The condition is proved by De Casteljau surface subdivision arithmetic, in which the recursive expressions elaborate that the control grid eventually converges to the surface. At last, two examples for the modeling of interpolation-type surface are discussed, one of which is a general surface and the other is a degenerate surface.展开更多
Tropical cyclones(TCs)are one of the most feared and deadly weather systems in the world.An air-sea coupled numerical model offers a more accurate description of physical processes between atmospheric-ocean fluids.An ...Tropical cyclones(TCs)are one of the most feared and deadly weather systems in the world.An air-sea coupled numerical model offers a more accurate description of physical processes between atmospheric-ocean fluids.An operational ocean-atmosphere-wave coupled modeling system is employed to improve the prediction accuracy of tropical cyclones in the NationalMarine Environmental Forecasting Center(NMEFC).Due to the urgent need for operational timeliness,the parallel performance of the operational forecasting system has been analyzed.The parallel algorithm,parallel partitioning grids,and other optimizations were tested after system deployment on the Lenovo cluster of the NMEFC.After optimization,a well-balanced performance of the system is obtained,and computing resources are reasonably utilized,thus laying the foundation for real-time tropical cyclone forecasting.展开更多
文摘Surface convexity is a key issue in computer aided geometric design, which is widely applied in geometric modeling field, such as physical models, industrial design, automatic manufacturing, etc. In this paper, a sufficient convexity condition of the parametric Bézier surface over rectangles is proposed, which is firstly considered as a sufficient convexity condition for the Bézier control grid. The condition is proved by De Casteljau surface subdivision arithmetic, in which the recursive expressions elaborate that the control grid eventually converges to the surface. At last, two examples for the modeling of interpolation-type surface are discussed, one of which is a general surface and the other is a degenerate surface.
基金supported by the National Natural Science Foundation of China (41976200)the project of Guangdong Ocean University (060302032106).
文摘Tropical cyclones(TCs)are one of the most feared and deadly weather systems in the world.An air-sea coupled numerical model offers a more accurate description of physical processes between atmospheric-ocean fluids.An operational ocean-atmosphere-wave coupled modeling system is employed to improve the prediction accuracy of tropical cyclones in the NationalMarine Environmental Forecasting Center(NMEFC).Due to the urgent need for operational timeliness,the parallel performance of the operational forecasting system has been analyzed.The parallel algorithm,parallel partitioning grids,and other optimizations were tested after system deployment on the Lenovo cluster of the NMEFC.After optimization,a well-balanced performance of the system is obtained,and computing resources are reasonably utilized,thus laying the foundation for real-time tropical cyclone forecasting.
