面向BIM的室内拓扑-栅格分层路径规划方法

针对传统路径规划方法在复杂大场景环境下的搜索空间大、效率低、避障安全性差等问题,本文提出了一种基于BIM的室内拓扑-栅格分层路径规划方法。首先,建立复杂室内环境的BIM模型,提取模型中结构、障碍物和通道的语义、几何及其关联信息,通过栅格抽象映射得到基础导航地图,并结合层次图思想,开展地图空间分层,获取拓扑-栅格分层地图;然后,利用细化算法,生成拓扑层中各子区域之间的离线先验路网,联合Dijkstra算法选取其中的最优路径,并基于自主改进的A*算法,快速高效搜索栅格层的最优路径,通过组合拼接拓扑层与栅格层的局部最优路径,构建完整的全局最优路径;最后,将本文方法与标准A*算法及蚁群算法作对比,在保证计算效率的同时,不仅缩小了路径搜索空间,还确保了最优路径的安全性,综合验证了所提路径规划方法的优越性。

Antimicrobial indole alkaloids from Tabernaemontana corymbosa

Four unreported monoterpene indole alkaloids,tabernaecorymines B−E(1−4),together with twenty-one known indole alkaloids(5−25)were obtained from the stem bark of Tabernaemontana corymbosa.Their structures and absolute configurations were elucidated by extensive spectroscopy,quantum chemical calculations,DP4+probability analyses and Mo2(OAc)4-induced electronic circular dichroism experiment.The antibacterial and antifungal activities of these compounds were evaluated and some of them showed significant activity against Staphylococcus aureus,Bacillus subtilis,Streptococcus dysgalactiae and Candida albicans.