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无序B样条曲线的曲面拟合算法 被引量:6
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作者 王文珂 李思昆 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2013年第5期679-685,共7页
针对目前无序曲线拟合算法不能控制拟合误差的问题,提出了利用B样条曲面拟合4条边界线及一组无序B样条曲线的算法.首先由边界曲线得到初始曲面,并将曲线曲面写成分段Bézier形式;然后借鉴曲面蒙皮的思想,得到关于待拟合曲面的方程组... 针对目前无序曲线拟合算法不能控制拟合误差的问题,提出了利用B样条曲面拟合4条边界线及一组无序B样条曲线的算法.首先由边界曲线得到初始曲面,并将曲线曲面写成分段Bézier形式;然后借鉴曲面蒙皮的思想,得到关于待拟合曲面的方程组,并对相邻的Bézier曲面施加C1连续约束;接着利用SVD以及能量优化来求得唯一的拟合曲面;最后在曲线曲面距离最大处插入节点,重复求解过程,直到误差满足要求.实验结果表明,与已有算法相比,该算法可以得到满足用户误差要求的、光滑的拟合曲面,且具有更好的数值稳定性. 展开更多
关键词 曲面拟合 无序曲线 误差可控 C1连续
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Multiple periodic oscillations in the radio light curves of NRAO 530 被引量:2
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作者 XIE MingJie WANG JunYi +2 位作者 AN Tao ZHENG Lin HAN Xu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第9期1798-1805,共8页
In this paper,the time series analysis method CLEANest is employed to search for characteristic periodicities in the radio light curves of the blazar NRAO 530 at 4.8,8.0 and 14.5 GHz over a time baseline of three deca... In this paper,the time series analysis method CLEANest is employed to search for characteristic periodicities in the radio light curves of the blazar NRAO 530 at 4.8,8.0 and 14.5 GHz over a time baseline of three decades.Two prominent periodicities on time scales of ~6.3 and ~9.5 a are identified at all three frequencies,in agreement with previous results derived from different numerical techniques,confirming the multiplicity of the periodicities in NRAO 530.In addition to these two significant periods,there is also evidence of shorter-timescale periodicities of ~5.0,~4.2,~3.4 and ~2.8 a showing lower amplitude in the periodograms.The physical mechanisms responsible for the radio quasi-periodic oscillations and the multiplicity of the periods are discussed. 展开更多
关键词 BLAZAR NRAO 530 PERIODICITY VARIABILITY DCDFT CLEANest
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