无索引空间数据库的基于最优点的集合最近邻查找算法

针对度量空间中的无索引空间数据库, 提出一种基于最优点的集合最近邻查找算法及其改进算法 采用真实数据集与人工生成的数据集对算法进行测试, 评估所提出算法的效率 实验结果表明, 所提算法的 效率优于组最近邻居查询算法, 并且对于高维数据空间, 所提出的算法有较高的稳定性 由于查询区域中数 据点的数量比较少, 改进的基于最优点的集合最近邻查找算法的效率总体上要比改进前高福建省自然科学基金资助项目( 2009J01288

the research on the classification methods for mangroves based on remote sensing image

红树林是一种宝贵资源，红树林生态系统是世界上生产力最高的四大生态系统之一，具有重大的生态和经济价值。由于红树林主要生长于潮间带浅滩，常规野外调查工作十分困难，工作量大，费用高，利用传统的森林资源调查方法难以准确定位和勾绘。卫星遥感技术为红树林生态研究及动态变化监测开辟了一条捷径，已经成为国内外红树林监测的主要技术之一。目前红树林遥感图像分类大多借助于传统的遥感图像分类方法，由于光谱特征上的相似（同物异谱及异物同谱现象），红树林遥感图像分类往往会出现严重的错分和漏分现象；并且传统的分类方法大多基于统计方法，根据各波段灰度数据的统计特征来进行分类，这些统计方法需要数据先验信息以及大量的训练样本，并...Mangroves are an invaluable natural resource, mangroves ecosystems is one of the most productive ecosystems in the world, and has significant ecological value and economic value. Since mangroves are mainly grown in intertidal shallows, the conventional field survey work is very difficult, which would lead to heavy workload and high cost. The traditional investigation methods for forest resources a...学位：理学博士院系专业：信息科学与技术学院_人工智能基础学号：2302009015418

Assessing the Areal Variation of Mangrove Coverage Forests in the Jiulongjiang Estuary of Fujian China with Remote Sensing Data

将lAndSAT MSS/TM/ETM数据与中国环境与灾害监测预报小卫星(HJ-1A/b)数据相结合,同时融合光谱信息、地学特征、纹理特征等多种信息,利用最大似然分类方法,提取了以福建省九龙江口红树林省级自然保护区为重点的九龙江口从20世纪70年代至2010年近40年间红树林面积的变化信息.结果表明九龙江口红树林面积在近40年呈现出减少(20世纪70—80年代)、缓慢增加(20世纪80—90年代)以及大幅度增长(2000年以后)3个主要阶段.其中人为活动(围垦、人工造林等)是九龙江口红树林面积大幅震荡的关键因子.By using the data of LANDSAT MSS/TM/ETM satellite and the Chinese environment and disaster monitoring satellite HJ-1A/B,the areal variation of mangrove coverage in the Jiulongjiang Estuary of Fujian province was investigated.Five multi-bands images were collected in 1976,1983,2002,2006 and 2010,respectively.The approach of maximum likelihood classification was used to detect mangrove from the images.It was found that the area of mangrove was likely decreasing during the period of 1970s-1980s(--60% drop).Recovery initiated during 1980s-2000s,and significant spread of mangrove occurred in the 2000s.The area of mangrove coverage in 2010 in the study region was about two times of the value in 1983.Such a highly variable temporal pattern was clearly different from that expected under natural forcing(--+4% annual change),suggesting that it was predominantly induced by human activities.国家重点基础研究发展计划(973)前期研究专项(2009CB426306