基于改进PSO-SVM的噪声稳健建筑物变形监测方法

对高层、超高层建筑物进行实时,高精度的变形监测对提前预防安全隐患,保证人民生命财产安全具有重要意义.建筑物变形作为一种典型的随机性和微弱性过程,噪声等误差的存在会影响从中提取有用的变形信息.针对该问题,提出一种改进粒子群(ParticleSwarmOptimization,PSO)算法优化支持向量机(SupportVe...     

大洋调查中海山地磁测量的静日变化校正方法

针对大洋调查中海山地磁测量时难以设立静日变化观测站的问题,提出了一种基于多项式拟合最小二乘算法的日变校正方法,即假设静日变化磁场可以用一个关于时间的高阶多项式来拟合,利用主测线和联络测线交点误差的最小二乘估计求得多项式的系数,从而得到静日变化曲线。从调查测得的磁场中减掉静日变化磁场即可得消除静日变化影响后的海山地磁异常。理论模型和实际资料处理都表明,这种方法不仅可以较好地消除静日变化的影响,而且用计算机实现也简单。为了提高静日变化校正结果,讨论了为提高静日变化校正效果,在大洋调查中测量海山地磁时应注意的几个问题。     

一种移动视频与地理场景的融合方法

快速准确地了解灾害现场状况是救灾过程中的重中之重。通常发生灾害都会使用无人机进行现场勘察,但是无人机视频难以与实际的地理场景关联起来,为此本文提出了一种移动视频与地理场景的融合方法。该方法首先采用具有仿射不变性的ASIFT算法检测特征点,将匹配后的特征点采用RANSAC算法进行迭代剔除噪点,计算视频与地理场景最优的透视变换矩阵模型参数;然后将计算得到的透视变换参数应用到视频数据,恢复视频角点坐标;最后通过内插得出所有视频帧的角点坐标,实现视频与DOM的精确融合。试验结果表明,对视频数据匹配的间隔帧越短,其整体融合精度越高,通过本文方法进行视频与地理场景融合的误差标准差低于10 m。     

最小割与深度学习联合优化的室内粘连点云分割方法

随着数字城市的发展,城市三维模型重建对三维点云结构化的需求与精度要求越来越高。如何有效准确地分割室内语义模型与三维重构是当前研究的热点问题。点云分割分类是室内点云结构化的重要基础,如何将粘连点云构件进行准确分割并用于室内点云结构化,是当前城市建模的难点。本文提出了一种面向室内粘连点云数据的分割分类方法。首先,利用深度学习网络处理室内点云数据;其次,对点云数据进行标签分类,得到目标标签点云;然后,利用欧氏算法对目标点云进行聚类分割,通过室内语义构件包围盒信息计算各目标中心点坐标与水平半径;最后,利用点云最小割实现室内粘连点云的准确分割。利用3组室内场景中获取的数据对分割方法的精度及有效性进行了验证。结果表明,该分割优化方法具有较高的精度与数据完整性。     

基于YOLOv3深度学习的海雾气象条件下海上船只实时检测

海雾气象条件下船只高精度检测识别面临较大困难,传统的目标识别、定位方法效果差强人意。作者围绕海雾气象条件下不同类型船只的实时检测问题,提出一种基于YOLOv3深度学习的实时海上船只检测新思路。首先构建清晰图片和模糊图片(海雾、雨)的判别方法,实现图片清晰度分类处理;其次为提高海雾气象条件下海上船只的实时检测精度,消除海雾遮挡对目标识别的影响,运用暗通道先验去雾方法对含有海雾的图像实行去雾;最后基于YOLOv3深度学习算法对精细处理后的图像进行船只实时检测。实验结果表明该方法能够在海雾气象条件下高效、准确地检测到船只,对海上复杂环境条件下的船只实时检测研究具有一定的理论指导意义。     

A hybrid ensemble method for improved prediction of slope stability

Accurate prediction of slope stability is a significant issue in geomechanics with many artificial intelligence (AI) techniques being utilised. However, the application of AI has not reached its full potential because of the lack of more robust algorithms. In this paper, we proposed a hybrid ensemble method for the improved prediction of slope stability using classifier ensembles and genetic algorithm. Gaussian process classification, quadratic discriminant analysis, support vector machine, artificial neural networks, adaptive boosted decision trees, and k‐nearest neighbours were chosen to be individual AI techniques, and the weighted majority voting was used as the combination method. Validation method was chosen to be the 10‐fold cross‐validation, and performance measures were selected to be the accuracy, the receiver operating characteristic curve, and the area under the receiver operating characteristic curve (AUC). Grid search and genetic algorithm were used for the hyperparameter tuning and weight tuning respectively. The results show that the proposed hybrid ensemble method has great potential in improving the prediction of slope stability. Compared with individual classifiers, the optimum ensemble classifier achieved the highest AUC value (0.943) and the highest accuracy (0.902) on the testing set, denoting that the predictive performance has been improved. The optimum ensemble classifier with the Youden's cut‐off was recommended for slope stability prediction with respect to the AUC value, the accuracy, the true positive rate, and the true negative rate. This research indicates that the use of the classifier ensembles, rather than the search for the ideal individual classifiers, might help for the slope stability prediction.     

Run‐off processes from mountains to foothills: The role of soil stratigraphy and structure in influencing run‐off characteristics across high to low relief landscapes

The critical zone features that control run‐off generation, specifically at the regional watershed scale, are not well understood. Here, we addressed this knowledge gap by quantitatively and conceptually linking regional watershed‐scale run‐off regimes with critical zone structure and climate gradients across two physiographic provinces in the Southeastern United States. We characterized long‐term (~20 years) discharge and precipitation regimes for 73 watersheds with United States Geological Survey in‐stream gaging stations across the Appalachian Mountain and Piedmont physiographic provinces of North Carolina. Watersheds included in this analysis had <10% developed land and ranged in size from 14.1–4,390 km². Thirty‐four watersheds were located in the Piedmont physiographic province, which is typically classified as a low relief landscape with deep, highly weathered soils and regolith. Thirty‐nine watersheds were located in the Appalachian Mountain physiographic province, which is typically classified as a steeper landscape with highly weathered, but shallower soils and regolith. From the United States Geological Survey daily mean run‐off time series, we calculated annual and seasonal baseflow indices (BFI), minimum, mean, and maximum daily run‐off, and Pearson's correlation coefficients between precipitation and baseflow. Our results showed that Appalachian Mountain watersheds systematically had higher minimum daily flows and BFI values. Piedmont watersheds displayed much larger deviations from mean annual BFI in response to year‐to‐year variability in precipitation. A series of linear regression models between 21 landscape metrics and annual BFIs showed non‐linear and complex terrestrial–hydrological relationships across the two provinces. From these results, we discuss how distinct features of critical zone architecture, with specific focus on soil depth and stratigraphy, may be dominating the regulation of hydrological processes and run‐off regimes across these provinces.     

BOOK REVIEWS

Books reviewed in this article: The Mexican Colonial Copper Industry. Elinore M. Barrett . The Control Revolution: Technological and Economic Origins of the Information Society . James R. Beniger . Land Degradation and Society . Piers M. Blaikie And Harold C. Brookfield , Eds . La carte, mode d'emploi. Roger Brunet . France: les dynamiques du territoire . Roger Brunet AND Jacques Sallois , EDS. At the Crossroads—The Mineral Problems of the United States . Eugene N. Cameron . A Census of One Billion People , Papers for International Seminar on China's 1982 Population Census. Li Chengrui , ED. Les Milieux “Naturels” du Globe . Jean Demangeot . The Geophysiology of Amazonia: Vegetation and Climate Interactions : Robert E. Dickinson , ED. Tenn-Tom Country . James F. Doster And David C. Weaver . Family Farming in Europe and America . Boguslaw Galeski And Eugene Wilkening , EDS. The Geography of Urban Transportation . Susan Hanson , Ed. Combating Desertification in Developing Countries . J. K. Jain , ED. Cartography in France—1660–1848. Science, Engineering and Statecraft . Josef W. Konvitz . Distribution of Distances in Pregeographical Space . Hans Kuiper . Physical Geography Lab Manual: A New Experimental Approach . Neal G. Lineback And John M. Harlin . Physical Geography: A Landscape Appreciation , 2nd ed. Tom L. Mc Knight . The Desert Is No Lady: Southwestern Landscapes in Women's Writing and Art . Vera Norwood And Janice Monk , EDS. France: A Geographical, Social, and Economic Survey . Philippe Pinchemel , translated, by D. Elkins and T. H. Elkins. Gene Banks and the World's Food . Donald L. Plucknett , Nigel J. H. Smith , J. T. Williams , And N. Murthi Anishetty . Latin American Development: Geographical Perspectives . David Preston , Ed. Making Sense of Development: An Introduction to Classical and Contemporary Theories of Development and Their Application to Southeast Asia . P. W. Preston . The History of the Countryside. Oliver Rackham . The Third World in Perspective . H. A. Reitsma AND J. M. G. Kleinpenning . The Industrial Geography of Australia . David C. Rich . The Recruiting Game , 2nd Ed., revised. John F. Rooney , JR. A Cultural Geography of North American Indians . Thomas E. Ross AND Tyrel G. Moore , EDS. Eastern Europe . Dean S. Rugg . Human Territoriality: Its Theory and History . Cambridge Studies in Historical Geography: 7. Robert David Sack . Experimental Fluvial Geomorphology . Stanley A. Schumm , M. Paul Mosley , AND William E. Weaver . The New Urban Landscape . David Schuyler . Atlas of American Women . Barbara Gimla Shortridge . Impacts of Hazardous Technology: The Psycho-Social Effects of Restarting TMI-1 . John Sorensen , Jon Soderstrom , Emily Copenhaver , Sam Carnes AND Robert Bolin . Modern Physical Geography , 3rd Ed., (Third Edition). Arthur N. Strahler AND Alan H. Strahler . India: Economic Resource Base and Contemporary Political Patterns . B. L. Sukhwal .     

星载合成孔径雷达成像处理

合成孔经雷达(Synthetic Aperture Radar,SAR)是当今微波遥感领域的研究热点,其全天候、全天时、高分辨率以及穿透地表等特点使其具备其他传感器不可比拟的优势,因此得到了极其广泛的应用。成像处理是SAR技术的核心部分。分析了星载SAR点目标回波信号模型和几种常用的星载SAR数字成像处理算法。以距离-多普勒算法为例,阐述了距离压缩和方位压缩的实质,详细讨论了多普勒参数估计、距离徙动校正和斑点噪声的去除等几个关键的问题。采用ERS-1卫星数据做了成像实验,并对SAR成像技术加以总结。     

Intermediate term earthquake prediction in the area of Greece: Application of the algorithm M8

The 3 strongest earthquakes,M7.0, which have occurred since 1973 in the area of Greece were preceded by a specific increase of the earthquake activity in the lower magnitude range. This activation is depicted by algorithm M8. This algorithm of intermediate term earthquake prediction was originally designed for diagnosis by Times of Increased Probability (TIPs) of the strongest earthquake,M8.0 worldwide (Keilis-Borok andKossobokov, 1984). At present the algorithm is retrospectively tested for smaller magnitudes in different seismic regions (Keilis-Borok andKossobokov, 1986, 1988). A TIP refers to a time period of 5 years and an area whose linear size is proportional and several times larger than that of the incipient earthquake source. Altogether the TIPs diagnosed by the algorithm M8 in the area of Greece occupy less than 20% and the Times of Expectation (TEs) about 10% of the total space-time domain considered. Also there is a current TIP for the southeastern Aegean sea and 1988–1992. It may specify the long-term prediction given inWyss andBaer (1981a,b).The results of this study are further evidence favoring applicability of algorithm M8 in diverse seismotectonic environment and magnitude ranges and support indirectly the hypothesis of self-similarity of the earthquake activity. It also implies the possibility of intermediate term prediction of the strongest earthquakes in the area of Greece.