Drainage basin object-based method for regional-scale landform classification: a case study of loess area in China

Landform classification is one of the most important procedures in recognizing and dividing earth surface landforms. However, topographical homogeneity and differences in regional-scale landforms are often ignored by traditional pixel- and object-based landform classification methods based on digital elevation models (DEMs). In this work, a drainage basin object-based method for classifying regional-scale landforms is proposed. Drainage basins with least critical areas are first delineated from DEMs. Then, terrain derivatives of mean elevation, mean slope, drainage density, drainage depth, and terrain texture are employed to characterize the morphology of the drainage basins. Finally, a decision tree based on the topographical characteristics of the drainage basins is constructed and employed to determine the landform classification law. The experiment is validated in the landform classification of regional-scale loess areas in China. Results show that clear boundaries exist in different landforms at the regional scale. Landform type in a specific region shows significant topographical homogeneity under its specific regional geomorphological process. Classification accuracies are 87.3 and 86.3% for the field investigation and model validation, respectively. Spatial patterns of classified landforms and their proximity to sediment sources and other factors can be regarded as indicators of the evolutionary process of loess landform formation.     

顾及邻域像元分类决策的遥感影像分类蚁群算法

为了进一步发掘蚁群算法的应用潜力,提高分类精度,将相关性引入分类规则发掘过程,试图在蚁群算法挖掘规则时既考虑像元的光谱信息,又兼顾邻近像元灰度的空间相关性,提出了一种优化的蚁群算法。算法包括对单个像元的分类规则挖掘和顾及邻域像元相关性的分类规则挖掘,单个像元的分类规则挖掘中,为使信息素缓和增加,避免陷入局部最优解,同时保证算法具有适当的收敛速度,采用自适应方案调整参数。顾及邻域像元相关性的分类规则挖掘中选用了优势类、优势度、类熵和邻域类相关性等4个指标,以反映邻域相关性对分类结果的影响。实验研究发现,顾及邻域蚁群算法的分类结果精度有了较为明显的提高,总体精度提高了3.00%,其优势主要体现在对建设用地、裸地等复杂地物的识别。研究结果表明,顾及邻域蚁群算法能够更准确地提取光谱信息复杂的地物,有效地减弱同物异谱和异物同谱现象的干扰。     

厦门市滨海砂质岸线生态化改造提升与适应性管理策略研究

滨海岸线作为休憩娱乐的主要目的地,是滨海旅游发展的资源基础。本研究以厦门市滨海砂质岸线为对象,采用指标评价、对比分析等方法,开展岸线环境质量评估、生态保护修复与开发利用适宜性分析、生态化改造提升方向研判和适应性管理策略研究工作。研究结果表明：(1)厦门市滨海砂质岸线环境质量整体良好,自然环境和开发利用层面环境质量均处于中等以上的砂质岸线长度约24.7 km,占砂质岸线总长度的96.2%;(2)根据岸线环境质量评估结果,厦门市总体上可以归纳为1至5级和无居民海岛型6大滨海砂质岸线类别,以及现状网红型、游憩娱乐型、观光游览型、休闲娱乐型、潜在发展型、保护修复型、严格保护型7大管理类型;(3)厦门市滨海砂质岸线的保护修复与改造提升方向主要体现在浴场、游乐场、休憩场所、公共卫生、交通等基础设施建设、人力资源服务、岸线修复工程项目建设三方面;(4)在维持岸线自然属性、保障岸线风险识别与管控目标要求、完善基础设施建设与人力资源服务基础上,进一步创新和提升厦门市岸线分类施策管理方式,以特许经营管理理念和模式进行一/二/三级砂质岸线的商业化开发利用与管理,并加强法律法规及管理办法等文件制定,明确岸线分类管理与协调利用权属信息,最终实现滨海砂质岸线资源自然 社会 经济与生态效益。本研究能够为厦门市滨海砂质岸线管理体系制定、保护修复格局优化等研究提供理论基础与实际案例支持,具有一定的理论与实际意义。     

基于SVM算法的海洋微生物种群多样性信息自适应分类方法

为了可以精准且高效地实现海洋微生物种群多样性信息分类, 本文提出一种基于支持向量机（Support Vector Machine, SVM） 算法的海洋微生物种群多样性信息自适应分类方法。通过无线传感器网络展开海洋微生物种群信息采集点的部署, 建立海洋微生物种群信息采集信道模型, 在带宽受距离约束条件下设计载频频率编码, 利用波特间隔均衡控制方法达到海洋微生物种群信息采集优化的目的。在核空间中, 对采集的海洋微生物种群信息展开谱聚类, 确定具有代表性的信息点, 同时引入SVM 对全部样本进行训练, 最终实现海洋微生物种群多样性信息自适应分类。实验结果表明： 所提方法的平均精度均值（mean Average Precision, mAP） 稳定在95%以上, 可以有效提升海洋微生物种群多样性信息自适应分类的准确性和分类效率。     

Sr和Yb两个元素对花岗岩理论的重要意义 ——花岗岩研究的哲学思考

花岗岩研究已有几百年的历史,可是花岗岩却没有形成自己独立的理论体系,也没有系统的花岗岩分类。花岗岩非常复杂,如何化繁为简,归纳出花岗岩最本质、最核心、最关键的标志,是一个非常棘手的任务。本文从哲学的角度出发,发现Sr和Yb可能是两个具有特殊含义的元素,特殊在于,它们不仅具有一般微量元素的特点,还具有特殊的功能,关键是它们的行为与花岗岩部分熔融后残留的变质矿物组成(如石榴石、斜长石等)有关。可能正是由于这个因素,才使Sr和Yb具有其他微量元素所不可匹敌的功能。本文按照Sr、Yb的排列组合提出了一个系统的花岗岩分类。对于花岗岩的地球动力学意义,学术界一直有争论,本文认为板块构造只能影响到大陆边缘,影响不到大陆内部。大陆演化研究最重要的任务是恢复大陆地质历史上的变化,如大陆地质演化不同时期曾经发生过的伸展和挤压(有的还有旋转,是挤压的副产品)、抬升和垮塌、造山与盆地、加厚与减薄等。如何识别上述变化及其过程,目前在方法学上还十分困难。依靠Sr、Yb及其与残留相平衡的理论则提出了一个方案,能够解决或大体解决上述问题。例如,埃达克岩(高Sr低Yb)代表加厚地壳,南岭型(非常低Sr高Yb)代表减薄地壳,浙闽型(低Sr高Yb)和广西型(高Sr高Yb)代表正常厚度的地壳,喜马拉雅型花岗岩(低Sr低Yb)代表中压与高压过渡的状况。因此,按照Sr和Yb的变化,即可大致恢复地质历史时期大陆地壳温压条件的变化,推测大陆地貌的变化(平原、丘陵、高原、山脉),探讨构造应力的变化(挤压导致加厚,伸展导致减薄)等。此外,不同类型花岗岩还与成矿有关,大体是:埃达克岩与金铜有关,南岭型与钨锡有关,喜马拉雅型与金有关,而浙闽型、广西型基本上是不利于成矿的。但是,实践中也有金铜钨锡在空间上共生的实例,则金铜与钨锡可能成因上或成矿时代上或控矿因素上有所不同。问题还很复杂,还有许多现象很难解释,笔者只是从宏观角度给出了一个思路,一个概念,很多细节并不清楚。研究表明,科学与哲学是密切相关的,哲学是科学的高度概括。本文尝试从哲学的角度对纷繁复杂的花岗岩进行归纳和简化,只是一个初步的尝试,还有更多问题需要认真研究。     

面向对象的eCognition遥感影像分类识别技术应用

以位于印度尼西亚Kalimantan热带雨林地区的1幅具有3个通道的雷达图像为研究对象,利用面向对象方法对高分辨率遥感影像的水体进行提取,在分割的基础上,经过分层分类,充分利用影像的光谱信息、拓扑信息、形状特征等构建知识库进行分类,实验结果理想,相对传统基于像素的图像分类分析方法结果图斑完整,提高了分类精度。     

A Solution to the Problem of Predicting the Suitability of Silty–clayey Materials for Cement-stabilization

Major geotechnical problems in construction involving silty–clayey soils are due to their low strength, durability and high compressibility of soft soils, and the swell–shrink nature of the overconsolidated swelling soils. Confronted with these problems, a suitable ground improvement technique is needed, for deep excavations in soft clays, for stability, durability and deformation control. Cement-stabilization is one of the alternatives. An increase in strength and durability, reduction in deformability are the main aims of this method. Conventional cement-stabilization methods are used mainly for surface treatment. However, the use of cement has recently been extended to a greater depth in which cement columns were installed to act as a type of soil reinforcement (deep cement–soil mixing and cement jet grouting). In situ engineering properties of these silty–clayey soils are often variable and difficult to predict. For this reason cement-stabilization methods have a basic target to control the aforementioned engineering properties of these clays so that the properties of a silty–clayey soil become more like the properties of a soft rock such as clayey shale or lightly cemented sandstone. So cement-stabilization of these soils is essential to control their engineering properties and to predict their engineering behaviour for construction. In an effort to predict, classify and study the suitability of silty–clayey soils for cement-stabilization both slaking and unconfined compressive strength tests were carried out on clayey–sand mixtures consisted of two types of clays, kaolin and bentonite. Finally diagrams were prepared to study the variation of slaking and strength due to compaction, curing time and cement percentage and also to predict areas of efficient cement-stabilization.