群体多属性决策方法及其应用

针对甄选员工这类群体多属性决策问题,将评价属性划分为主观评价属性和客观评价属性,并且假设方案在主观评价属性下的评价值采用区间数的形式来表示专家评价值的不确定性和模糊性。针对每一主观评价属性设定一组与之对应的专家重要性权重值,反映决策者在不同评价属性中的重要性程度,同时考虑到专家评价值的相似度,将专家评价值进行集结得到专家群体关于方案集的决策矩阵。通过计算各方案与理想方案的相似度,据此对方案进行优劣排序。最后给出该方法在员工甄选决策中的应用实例。     

多个空间高斯源信号情况下成组三维图像特征提取方法

针对功能磁共振成像数据中含有多个高斯信号源的盲源分离问题,介绍了一种成组典型相关分析方法(Group BSS-CCA)。这个方法的组分析框架参照了GIFT工具箱中的Group ICA算法,具体的典型相关分析方法应用的是Friman等人提出的BSS-CCA算法。以验证该方法的有效性为目的,设计了仿真实验;结果表明,该方法能较好识别出混合在人脑功能磁共振成像数据的2个空间高斯信号。Group BSS-CCA算法对研究人脑的功能磁共振成像数据具有较高的实用价值。     

一种空间机器人用复杂末端执行装置的可靠性验证方法

对空间机器人用末端执行装置的功能展开分析，确定表征产品功能的可靠性特征参数和分布类型，提出一种可靠性试验验证方法。结合空间站机械臂末端执行器给出具体应用验证，包括产品分析、可靠性模型的建立、特征量和分布类型的确定、样本量的选取和故障判据等内容，为其他复杂空间产品的可靠性验证提供思路。该验证方法基于计量型可靠性试验的基本思路，通过极小的样本量完成产品的可靠性验证，大幅缩减研制经费，降低科研成本。     

CFRP薄壁圆筒壳端面磨削工艺研究

阵列碳纤维复合材料管是由碳纤维增强复合材料(CFRP)薄壁圆筒壳阵列排布后粘接制备而成，兼具碳纤维复合材料和蜂窝结构的优异性能，是一种新型的可应用于深空探测反射面板的理想材料结构。由于材料和制备方面的特殊性，在阵列碳纤维复合材料管加工过程中会由于磨削力过大导致多种加工损伤，为其高效低损伤加工带来了挑战。本文开展CFRP薄壁圆筒壳磨削加工正交试验，系统研究磨削深度、切出角度、主轴转速、进给率对磨削力的影响规律和影响程度。研究结果表明:工艺参数对水平面合力的影响程度依次为进给率、磨削深度、切出角度、主轴转速，对轴向力的影响程度依次为切出角度、主轴转速、进给率、磨削深度。研究对阵列碳纤维复合材料管高效低损伤加工工艺的制订具有参考意义。     

Improving performance of macro electrolyte jet machining of TC4 titanium alloy: Experimental and numerical studies

Electrolyte jet machining (EJM) is a promising method for shaping titanium alloys due to its lack of tool wear, thermal and residual stress, and cracks and burrs. Recently, macro-EJM has attracted increasing attention for its high efficiency in machining wide grooves or planes. However, macro-EJM generates large amounts of electrolytic products, thereby increasing the difficulty of rapid product removal with a standard tool and reducing the surface quality. Therefore, for enhanced product transport, a novel tool with a back inclined end face was proposed for macro-EJM of TC4 titanium alloy. For comparison, also proposed were ones with a standard flat end face, a front inclined end face, and both front and back inclined end faces. The flow field distributions of all proposed tools were simulated numerically, and experiments were also conducted to validate the simulation results. The results show that one with a 5° back inclined end face can decrease the low-velocity flow zone in the machining area and increase the high-velocity flow zone at the back end of tool, thereby promoting rapid product removal. A relatively smooth bright-white groove surface was obtained. The same tool also resulted in the highest machining depth and material removal rate among the tested ones. In addition, rapid product removal was beneficial to the subsequent processing. Because of its rapid product removal, the machining depth and material removal rate during deep groove machining using the tool with a 5° back inclined end face were respectively 7% and 14% higher than those produced using a standard one. Moreover, the lowest bottom height difference of 0.027 mm can be obtained when the step-over value was 8.2 mm, and a plane with a depth of 0.285 mm and a bottom height difference of 0.03 mm was fabricated using the tool with a 5° back inclined end face.