Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区研究》
Abstract：运用遥感手段结合历史时期遥感影像数据，以天山云杉 (Picea schrenkiana var. tianschanica)林生境特征为固定因子，结合植被指数分析、地形因子分析、主成分分析及面向对象的决策树分类的方法提取历史时期天山云杉林的空间分布信息，从而为历史资料缺失情境下的天然林资源保护工程实施效益评价提供支持。研究表明：① 将天山云杉林的年龄特征作为固定因子，以现状年高空间分辨率遥感影像及森林资源二类调查数据作为本底资料，在面向对象分类方法支持下可以很好的从历史时期的遥感影像中提取出天山云杉林的历史空间分布信息，提取精度可达93.3%；② 在植被指数因子中， NDVI对天山云杉林指示性最好，并确定用于天山云杉林提取的最佳NDVI值域为［0.35，0.8］；③ 地形因子及主成分分析方法可以大大压缩影像的冗余信息，在提升云杉林信息提取的精度的同时提高运行速度。从整体来看，利用历史时期遥感影像并结合天山云杉林的生境特征，可以很好的提取出历史时期云杉林空间分布信息，从而为资料缺失情境下的森林资源管理措施制定及应对气候变化提供数据支持。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-18 Cooperative journals: 《计算机应用研究》
Abstract： With regards to the low precision and poor robustness of fuzzy C-means clustering algorithm (FCM) in the underdetermined mixing matrix estimation, this paper proposed an algorithm using genetic simulated annealing optimized FCM(GASA-FCM) based mixed clustering with hough transform to solve underdetermined mixing matrix estimation. It could combine the global search, high-precision advantages of simulated annealing algorithm(SA) and powerful search ability of space of genetic algorithm(GA) , FCM assigned the clustering center point obtained by genetic simulated annealing algorithm, which avoided the randomness of initial selection. The center of each kind of data obtained by clustering by hough transform is modified to improve the estimation accuracy of the mixing matrix. Experimental results show that the proposed algorithm significantly improves the stability of the algorithm and the accuracy of the mixing matrix estimation, and has certain validity and feasibility.
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