Positioning method of a cylindrical cutter for ruled surface machining based on minimizing one-sided Hausdorff distance

Motivated by the definition of the machining errors induced by tool path planning methods, a mapping curve of the tool axis of a cylindrical cutter is constructed on the tool surface. The mapping curve is a typical one that can be used to express the closeness between the tool surface and the surface to be machined. A novel tool path planning method is proposed for flank or plunge milling ruled surfaces based on the minimization of the one-sided Hausdorff distance （HD） from the mapping curve to the surface to be machined. It is a nonlinear optimization problem in best uniform approximation （BUA） or Chebyshev sense. A mathematical programming model for computing the minimum one-sided HD is proposed. The linearization method of the programming model is provided and the final optimal solutions are obtained by simplex method. The effectiveness of the proposed BUA method is verified by two numerical examples and compared with the least squares （LS） and double point offset （DPO） methods. The variation in tool orientation induced by the optimization of the tool positions is also evaluated.

基于前景理论的犹豫模糊语言绿色供应商优选决策

文章研究了不确定风险决策下的绿色供应商评价问题,提出一种有限理性下的多属性决策方法。首先通过犹豫模糊语言来表征评价信息,针对现有犹豫模糊语言距离测度公式的不足,提出一种更客观地距离计算公式;将前景理论和PROMETHEE方法相结合,设计出一种能体现决策者行为特征的决策方法。最后应用该方法为某手机企业的绿色电池供应商进行评价并给出最佳合作伙伴,证明了方法的可行性和有效性。

对称拟向量均衡问题的适定性

研究实Banach空间中对称拟向量均衡问题的适定性。定义对称拟向量均衡问题的近似解序列,以此分别给出了对称拟向量均衡问题的适定性和唯一适定性概念。证明在一定条件下,对称拟向量均衡问题的适定性等价于ε→0时,ε-近似解集与解集间的Hausdorff距离的极限为零。唯一适定性则等价于解集非空且ε→0时,ε-近似解集的直径的极限为零。

一种基于平行系数的双线主干道识别方法

城市主干道路的识别和提取是路网综合的关键步骤,而双线道路则是大比例尺地图数据中道路综合的难点。针对城市双线主干道识别问题,基于Gestalt视觉准则构建候选双线主干道线对的约束条件,提出了一种基于平行系数的双线主干道识别方法。首先对道路网数据进行拓扑处理,然后借助道路匹配思想,结合Hausdorff(HD)距离匹配方法识别出可能构成双线主干道的候选线对。再对候选线对进行平行系数计算,当平行系数满足阈值条件时,就判定该线对是构成双线主干道的弧段。最后根据构成双线主干道路段间的空间关系,将已识别的弧段连接成整条道路。实验证明,选取典型样本方法正确设置阈值后,该方法能有效地提取道路网中的双线主干道。