基于MIMU的微小型组合导航系统研究

介绍了基于MEMS技术的MIMU的构成、工作原理及安装误差补偿方法,设计了-种由MIMU与微小型GPS接收器组成的导航系统,系统采用闭环反馈的校正方式,能对MIMU的位置、速度误差、数字平台误差及微惯性器件误差作出最优估计并实施反馈.仿真分析表明,该组合方式能抑制滤波发散,提高长期导航精度.该系统具有体积小、重量轻、功耗低的特点,可适用于微小型飞行器的导航任务.     

2-氟异丁酸甲酯合成新工艺

2-氟异丁酸甲酯作为农药中间体可以合成含氟三嗪基团类除草剂.在分析评估各合成工艺路线的基础上,研究了以2-羟基异丁酸甲酯先与氯化亚砜反应得到中间体氯代亚硫酰酯,在催化剂存在下再与氟化氡反应得到产品2-氟异丁酸甲酯的合成工艺,分析并实验优化了主要的合成工艺参数:氯化亚砜与2-羟基异丁酸甲酯的摩尔比为1:1.7,氯化反应温度为-10～0℃,氯化反应时间为3～4h,收率达75%.     

肉桂酸工业化合成方法的研究探讨

介绍了肉桂酸的合成方法及改进,并对几种合成方法进行了分析。     

三支决策视角下的属性约简加速方法

Attribution reduction is one of the key topics in the field of rough set theory. Based on such theory, the concept of ensemble attribute reduction has been proposed. The ensemble reduction is to divide the sample into multiple decision systems in terms of the decision categories and then calculate them separately. Although ensemble attribute reduction balances the requirements of various decision classes, the corresponding time of attribute reduction is increased. To solve this problem, an attribute reduction acceleration method based on sequential three-way decisions is proposed. The specific steps are as follows: (1) The importance of the attribute in the decision system is calculated. (2) The attributes are divided into three groups in terms of the significance degree of corresponding attribute. Then, the attributes with maximal significance degree are classified into the positive domain, the attributes with zero significance degree are classified into the negative domain, and other attributes will be classified into the boundary domain. (3) The significance degree of the attributes in the boundary domain is calculated cyclically and the obtained result is divided, until theconstraint is satisfied. 8 UCI data sets are selected to conduct experiments in the traditional attribute reduction and ensemble reduction environments, respectively. The experimental results show that, under the premise of ensuring the classification performance, the proposed method can effectively reduce the time of attribute reduction in such two environments.