结合POI数据的道路自动选取方法

人们对道路重要性的认知与道路周边设施有重要关系,针对现有地图综合道路选取方法中对语义特征考虑不足的问题,将POI数据引入到道路的语义特征分析中,提出一种综合考虑道路空间特征和语义特征的道路综合自动选取方法。首先,结合POI位置数据构造了道路语义特征度量的3个新参量：设施点密度、重要设施比率和专题设施比率;然后,与道路长度、连接值、总深度值、平均线密度等反映道路几何、拓扑和分布特征的度量参量一起,通过归一化和熵值法赋权进行整合计算,得到道路重要性值;最后,综合考虑道路重要性值、道路stroke构成和stroke连通度的约束条件进行道路的分步选取。实验结果表明,该方法在保留主要道路、保持道路分布疏密特征和道路连通性的同时,较好地顾及了道路的语义特征信息。     

位场自动反演技术的研究现状及意义

本文首先叙述了重、磁异常自动反演技术的特点。与传统的定性分析重、磁场分布特征的方法不同,重、磁异常自动反演方法通过反演得到地下场源分布,即地下密度或磁性的分布特征。由于密度体或磁性体与地质体的关系更为直接,因此这种新一代重、磁解释成果及图件将成为人们从新的角度来认识地质构造的基础材料。文中不但阐述了该方法的研究现状,同时也说明了存在的问题。     

冰雹云雷达回波自动识别系统

利用CAPPI资料对立体风暴进行识别，计算并提供出实用的风暴结构参数，采用矩心踊跃法和矩不变量法相结合对单体风暴和混合性风暴回波进行跟踪；最小二第线性外推预报；根据WSD－88D的冰雹算法，在风暴结构基础上本文建立了Windows98操作平台上冰雹识别系统，经单站1年11次强对流天气过程的资料检验，结果表明：雹云识别精度达82％。系统建立了大量人机对话框以方便用户，增加实用性及推广性。     

基于超像元词包特征和主动学习的高分遥感影像变化检测

为解决高分辨率遥感影像变化检测中存在底层特征缺乏语义信息、像元级的检测结果存在“椒盐”现象以及监督分类中样本标注自动化程度较低,本文提出一种基于超像元词包特征和主动学习的变化检测方法。首先采用熵率分割算法获取叠加影像的超像元对象;其次提取两期影像像元点对间的邻近相关影像特征（相关度、斜率和截距）和顾及邻域的纹理变化强度特征（均值、方差、同质性和相异性）,经线性组合作为像元点对的底层特征;然后基于像元点对底层特征利用BOW模型构建超像元词包特征,并采用一种改进标注策略的主动学习方法从无标记样本池中优选信息量较大的样本,且自动标注样本类别;最后训练分类器模型完成变化检测。通过选用2组不同地区的GF-2影像和Worldview-Ⅱ影像作为数据源进行实验,实验结果中2组数据集的F1分数分别为0.8714、0.8554,正确率分别为0.9148、0.9022,漏检率分别为0.1681、0.1868,误检率分别为0.0852、0.0978。结果表明,该法能有效识别变化区域、提高变化检测精度。此外,传统主动学习方法与改进标注策略的主动学习方法的学习曲线对比显示,改进的标注策略可在较低精度损失下,有效提高样本标注自动化程度。     

《军官地图集》电子版的设计

本文系统阐述了《军官地图集》电子版的设计和研制中的若干问题,包括《军官地图集》电子版的总体设计、数据库设计、自动分幅设计以及专题图设计等。总体设计主要包括系统的结构设计、地理数据库设计、各功能模块设计等几部分。在地图集系统中,多比例尺海量地理数据的应用必然要求有强大的数据库支持,系统中采用了易于存储、便于管理的数据结构,并对数据库的各类数据描述表进行了详细说明。自动分幅设计是电子地图集的一个新功能,本文提出了电子地图集的分幅方式:经纬线分幅、矩形分幅、名称分幅和区域分幅,并阐述了它们各自的优缺点。《军官地图集》电子版中的专题地图在设计上突出了图集的系统性和军事特色,本文提出了该电子版中专题地图设计的原则和方法。根据该电子版的设计和制作过程,同时提出了电子地图集制作的步骤,并阐明了电子地图集设计中的不足和发展方向。     

地理空间数据自动综合方法的研究现状与发展趋势

多年来人们已经报道了很多自动综合方法。这些方法确实解决了地理空间数据自动综合中的很多重要问题,但这些方法也有明显的缺陷和应用范围。本文对这些方法进行了研究,研究内容包括这些方法的分类、原理、优缺点和适用范围,并提出了今后自动综合方法的研究发展趋势。     

Degradation of rock fracture asperities in unloading,reloading, and reversal

Among the constitutive models for rock fractures developed over the years, Barton's empirical model has been widely used. Although Barton's failure criterion predicts peak shear strength of rock fractures with acceptable precision, it has some limitations in estimating the peak shear displacement, post‐peak shear strength, dilation, and surface degradation. The first author modified Barton's original model in order to address these limitations. Barton proposed his model for degradation of fracture asperities in unloading, reloading, and shear displacement reversal based on just one cyclic direct shear test. In this study, a database of results of 18 cyclic direct shear tests available in the literature was collected and analyzed. Modifications were made to Barton's original model (in terms of fracture cyclic shearing) to make it consistent with the modified model proposed by the first author. Copyright © 2010 John Wiley & Sons, Ltd.     

Explicit integration of a porosity‐dependent hydro‐mechanical model for unsaturated soils

An adaptive substepping explicit integration scheme is developed for a porosity‐dependent hydro‐mechanical model for unsaturated soils. The model is referred to as the modified σ –Θ model in this paper, which features the employment of the subloading surface plasticity and the stress–saturation approach. On numerical aspects, convex/nonconvex subloading surfaces in the σ –Θ space may result in incorrect loading–unloading decisions during the integration. A new loading–unloading decision method is developed here to solve the problem and then embedded into the explicit integration scheme for the modified σ –Θ model. In addition, to enhance the accuracy of the explicit integration, local errors from both hydraulic and mechanical components are included in the error control for each substep. A drift correction method is also developed to ensure the state point lies on the subloading surface in the σ –Θ space within a set error level. The performance of the loading–unloading decision method for the modified σ –Θ model is discussed through comparing it with the conventional loading–unloading decision method. The importance of involving the hydraulic component in the error control is also demonstrated. The accuracy and efficiency of the proposed adaptive substepping explicit integration scheme for the modified p–Θ model are also studied via several numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.     

Explicit integration of bounding surface model for the analysis of earthquake soil liquefaction

This paper presents a new plasticity model developed for the simulation of monotonic and cyclic loading of non‐cohesive soils and its implementation to the commercial finite‐difference code FLAC, using its User‐Defined‐Model (UDM) capability. The new model incorporates the framework of Critical State Soil Mechanics, while it relies upon bounding surface plasticity with a vanished elastic region to simulate the non‐linear soil response. Stress integration of constitutive relations is performed using a recently proposed explicit scheme with automatic error control and substepping, which so far has been employed in the literature only for constitutive models aiming at monotonic loading. The overall accuracy of this scheme is evaluated at element level by simulating cyclic loading along complex stress paths and by using iso‐error maps for paths involving change of the Lode angle. The performance of the new constitutive model and its stress integration scheme in complex boundary value problems involving earthquake‐induced liquefaction is evaluated, in terms of accuracy and computational cost, via a number of parametric analyses inspired by the successful simulation of the VELACS centrifuge Model Test No. 2 studying the lateral spreading response of a liquefied sand layer. Copyright © 2009 John Wiley & Sons, Ltd.     

皖江中东部雾的客观预报自动化业务系统

介绍了一种雾的客观预报方法，并研制了一个与ＳＴＹＳ接口的雾的客观预报自动化业务系统，对雾有一定的预报能力。