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基于遗传算法的复杂平面曲线形状误差计算 被引量:3
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作者 廖平 喻寿益 《计量学报》 CSCD 北大核心 2003年第3期181-184,224,共5页
提出了归一化实数值编码的遗传算法 ,建立了平面复杂曲线形状误差的数学模型 ,并运用归一化实数值编码的遗传算法进行求解。仿真实验证明 ,其计算精确度非常高 ,可以达到任意给定的精度 。
关键词 计量学 形状误差 遗传算法 平面复杂曲线 数据处理
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基于分割逼近法和遗传算法的复杂平面曲线形状误差计算 被引量:1
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作者 廖平 《机械科学与技术》 CSCD 北大核心 2009年第9期1121-1124,共4页
提出了复杂平面曲线形状误差的定义,建立了复杂平面曲线形状误差数学模型,给出了快速计算测点到平面NURBS曲线的最小距离的分割逼近算法,确立了分割逼近法和归一化实数值编码遗传算法相结合计算复杂平面曲线形状误差的具体步骤。大量算... 提出了复杂平面曲线形状误差的定义,建立了复杂平面曲线形状误差数学模型,给出了快速计算测点到平面NURBS曲线的最小距离的分割逼近算法,确立了分割逼近法和归一化实数值编码遗传算法相结合计算复杂平面曲线形状误差的具体步骤。大量算例表明:在不考虑测量仪器本身误差的前提下,采用分割逼近法和遗传算法相结合计算复杂平面曲线测点形状误差得到的是全局最优解,符合最小区域法的评定标准,为复杂平面曲线误差评定开辟了新的途径。该算法易于计算机实现,非常适用于三坐标测量机。 展开更多
关键词 遗传算法 平面复杂曲线形状误差 数据处理
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A manifold approach to generating iso-scallop trajectories in three-axis machining 被引量:2
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作者 CHEN XuBing LI WenLong XIONG YouLun 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期131-139,共9页
A novel approach of iso-scallop trajectory generation for smooth manifold surfaces has been developed. Firstly,by defining homeomorphism mapping relations and differentiable structures,the smooth manifold surface is m... A novel approach of iso-scallop trajectory generation for smooth manifold surfaces has been developed. Firstly,by defining homeomorphism mapping relations and differentiable structures,the smooth manifold surface is mapped into several Euclidean planes,thus its trajectory generation can be decomposed into planar curve-filling tasks. Secondly,in the generation of direction-parallel trajectories,the calculation of the cutting interval and the curvature is given,depending on the generation of the first curve in the projection view. Thirdly,after automatic adherences of inverse projection curves,the filled curves are mapped into the original surface inversely to form trajectories. Although the required trajectories are iso-scallop,the trajectory intervals are variable according to the curvature changes at the projection point,which is advantageous to improving the trajectory quality. The proposed approach has appealing merits of dimensionality reduction,which decreases the algorithm complexity. Finally,numerical and machining examples are given to illustrate its feasibility and validity. 展开更多
关键词 smooth manifold surface iso-scallop trajectory three-axis machining homeomorphism mapping REGULARITY
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Fast adaptive flat-histogram ensemble to enhance the sampling in large systems
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作者 XU Shun ZHOU Xin +1 位作者 JIANG Yi WANG YanTing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第9期5-10,共6页
An efficient novel algorithm was developed to estimate the Density of States(DOS) for large systems by calculating the ensemble means of an extensive physical variable, such as the potential energy, U, in generalized ... An efficient novel algorithm was developed to estimate the Density of States(DOS) for large systems by calculating the ensemble means of an extensive physical variable, such as the potential energy, U, in generalized canonical ensembles to interpolate the interior reverse temperature curve β_s(U)=SU/U, where S(U) is the logarithm of the DOS. This curve is computed with different accuracies in different energy regions to capture the dependence of the reverse temperature on U without setting prior grid in the U space. By combining with a U-compression transformation, we decrease the computational complexity from O(N3/2) in the normal Wang Landau type method to O(N1/2) in the current algorithm, as the degrees of freedom of system N. The efficiency of the algorithm is demonstrated by applying to Lennard Jones fluids with various N, along with its ability to find different macroscopic states, including metastable states. 展开更多
关键词 molecular dynamics simulations enhanced sampling density of states generalized canonical ensemble flat-histogram ensemble
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