以东江流域土地利用解译结果为基础,采用转移矩阵、移动窗口法和景观格局指数对 1990-2016 年对东江流域的景观格局时空变化进行分析,并结合地形因子、交通通达度因子和限制转化因子采用 FLUS(Future Land Use Simulation)模型对流域未...以东江流域土地利用解译结果为基础,采用转移矩阵、移动窗口法和景观格局指数对 1990-2016 年对东江流域的景观格局时空变化进行分析,并结合地形因子、交通通达度因子和限制转化因子采用 FLUS(Future Land Use Simulation)模型对流域未来景观格局进行预测。结果表明:(1)自 1990 年以来,研究区的 7 种土地利用类型皆发生了变化,其中建设用地由于林地和耕地的大量转入增加最明显。(2)1990-2016 年,流域景观破碎化呈现以河道为中心向东西两侧减小的趋势,景观多样性呈现流域上游小,下游大的趋势,且高值区在经济较发达的城镇地区。园地的景观破碎程度最高、林地的优势度减弱,城镇建设用地的集聚度增加。(3)2016-2042 年,流域各用地类型变化率不大,景观破碎化和多样性程度虽有增加但增长速度相对放缓。展开更多
针对IRRT*(informed rapidly-exploring random trees star)算法在机器人路径规划中搜索效率低、收敛速度慢的问题,将APF(artificial potential field method)与IRRT*算法相结合,提出APF-IRRT*混合算法.仿真实验结果表明:相对于其他3种...针对IRRT*(informed rapidly-exploring random trees star)算法在机器人路径规划中搜索效率低、收敛速度慢的问题,将APF(artificial potential field method)与IRRT*算法相结合,提出APF-IRRT*混合算法.仿真实验结果表明:相对于其他3种算法,APF-IRRT*算法的搜索时间、节点数目、路径长度的数值均最小;APF-IRRT*算法对地图的复杂性以及面积的变化均有较强的适应能力.展开更多
针对四轴飞行器很难通过运动控制来完成快速扩展随机树(Rapidly-exploring Random Tree,RRT)所生成运动轨迹的问题,提出动力学和运动学约束的RRT算法.采用固定最终状态和固定最终时间控制器改进算法,通过动力学和运动学约束产生四轴飞...针对四轴飞行器很难通过运动控制来完成快速扩展随机树(Rapidly-exploring Random Tree,RRT)所生成运动轨迹的问题,提出动力学和运动学约束的RRT算法.采用固定最终状态和固定最终时间控制器改进算法,通过动力学和运动学约束产生四轴飞行器可执行的路径,对比实际四轴飞行器行走的路径与期望的路径,对RRT重新布线,调节其行走路径,保证算法的渐近最优性.仿真实验及实物测试结果表明,该算法可以运用到四轴飞行器运动规划中,在实际应用中具有一定的价值.展开更多
In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urb...In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urbanization.In this paper,a simple negative exponential function was presented to verify its applicability in 19 typical sloping urban areas in China.The function fits well for all case urban areas(R^(2)≥0.951,p<0.001).The parameters of this function clearly describe two fundamental attributes:initial value a and decline rate b.Between 2000 and 2020,a tends to increase,while b tends to decrease in all urban areas,confirming the hypothesis of mutual promotion between flatland densification and sloping land expansion.Multiple regression analysis indicates that the built-up land density and the ruggedness of background land can explain 70.7%of a,while the average slope ratio of built-up land to background land,the built-up land density and the built-up land area can explain 82.1%of b.This work provides a quantitative investigative tool for distribution of urban built-up land density along slope gradient,aiding in the study of the globally increasing phenomenon of sloping land urbanization from a new perspective.展开更多
文摘针对IRRT*(informed rapidly-exploring random trees star)算法在机器人路径规划中搜索效率低、收敛速度慢的问题,将APF(artificial potential field method)与IRRT*算法相结合,提出APF-IRRT*混合算法.仿真实验结果表明:相对于其他3种算法,APF-IRRT*算法的搜索时间、节点数目、路径长度的数值均最小;APF-IRRT*算法对地图的复杂性以及面积的变化均有较强的适应能力.
文摘针对四轴飞行器很难通过运动控制来完成快速扩展随机树(Rapidly-exploring Random Tree,RRT)所生成运动轨迹的问题,提出动力学和运动学约束的RRT算法.采用固定最终状态和固定最终时间控制器改进算法,通过动力学和运动学约束产生四轴飞行器可执行的路径,对比实际四轴飞行器行走的路径与期望的路径,对RRT重新布线,调节其行走路径,保证算法的渐近最优性.仿真实验及实物测试结果表明,该算法可以运用到四轴飞行器运动规划中,在实际应用中具有一定的价值.
基金supported by the project of the National Natural Science Foundation of China entitled“Distribution and change characteristics of construction land on slope gradient in mountainous cities of southern China”(No.41961039).
文摘In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urbanization.In this paper,a simple negative exponential function was presented to verify its applicability in 19 typical sloping urban areas in China.The function fits well for all case urban areas(R^(2)≥0.951,p<0.001).The parameters of this function clearly describe two fundamental attributes:initial value a and decline rate b.Between 2000 and 2020,a tends to increase,while b tends to decrease in all urban areas,confirming the hypothesis of mutual promotion between flatland densification and sloping land expansion.Multiple regression analysis indicates that the built-up land density and the ruggedness of background land can explain 70.7%of a,while the average slope ratio of built-up land to background land,the built-up land density and the built-up land area can explain 82.1%of b.This work provides a quantitative investigative tool for distribution of urban built-up land density along slope gradient,aiding in the study of the globally increasing phenomenon of sloping land urbanization from a new perspective.
