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Spatial-temporal Analysis of Daily Air Quality Index in the Yangtze River Delta Region of China During 2014 and 2016

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Chinese Geographical science 2019年第3期29卷 382-393页

作者： YE Lei OU Xiangjun school of Geographic science Nantong University school of Geography Geomatics and PlanningJiangsu Normal University

Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality and its dominant factors is of great importance to regional environmental management. In contrast to traditional air pollution researches which only concentrate on a single year or a single pollutant, this paper analyses spatiotemporal patterns and determinants of air quality in disparate regions based on the air quality index(AQI) of the Yangtze River Delta region(YRD) of China from 2014 to 2016. Results show that the annual average value of the AQI in the YRD region decreases from 2014 to 2016 and exhibit a basic characteristic of ‘higher in winter, lower in summer and slightly high in spring and autumn'. The attainment rate of the AQI shows an apparently spatial stratified heterogeneity, Hefei metropolitan area and Nanjing metropolitan area keeping the worst air quality. The frequency of air pollution occurring in large regions was gradually decreasing during the study period. Drawing from entropy method analysis, industrialization and urbanization represented by per capita GDP and total energy consumption were the most important factors. Furthermore, population agglomeration is a factor that cannot be ignored especially in some mega-cities. Limited to data collection, more research is needed to gain insight into the spatiotemporal pattern and influence mechanism in the future.

关键词： air quality index(AQI) spatial-temporal evolution contributing factors Yangtze River Delta(YRD)

Simulation of land-use Scenarios for Beijing Using CLUE-S and Markov Composite Models

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Chinese Geographical science 2013年第1期23卷 92-100页

作者： HU Yecui ZHENG Yunmei ZHENG Xinqi school of land science & Technique China University of Geosciences Key Laboratory of land Consolidation Ministry of Land and Resources

This study investigated and simulated land use patterns in Beijing for the year 2000 and the year 2005 from the actual land use data for the year 1995 and the year 2000,respectively,by combining spatial land allocation simulation using the CLUE-S model,and numerical land demand prediction using the Markov *** simulations for 2000 and 2005 were confirmed to be generally accurate using Kappa *** the land-use scenarios for Beijing in 2015 were simulated assuming two modes of development:1) urban development following existing trends;and 2) under a strict farmland *** simulations suggested that under either mode,urbanized areas would expand at the expense of land for other *** expansion was predicted to dominate the land-use conversions between 2005 and 2015,and was expected to be accompanied by an extensive loss of *** key susceptible to land-use changes were found to be located at the central urban Beijing and the surrounding regions including Yanqing County,Changping District and Fangshan ***,the simulations predicted a considerable expansion of urban/suburban areas in the mountainous regions of Beijing,suggesting a need for priority monitoring and protection.

关键词： CLUE-S model land use Markov model scenario simulation Beijing

Zircon U-Pb Age,Geochemical Data:Constraints on the Origin and Tectonic Evolution of the Metamafic Rocks from Longmuco-Shuanghu-Lancang Suture Zone,Tibet

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Journal of Earth science 2017年第3期28卷 422-432页

作者： Yanwang Wu Cai Li Mengjing Xu Chaoming Xie Ming Wang school of Geology and geomatics Tianjin Chengjian University College of Earth science Jilin University

Bulk-rock major and trace elements and zircon U-Pb data are reported for Permian metamafic rocks from Guoganjianan, in the western part of Longmuco-Shuanghu-Lancang suture zone. These results offer new insights into mantle source characteristics and geodynamic setting of Permian ophiolitic fragments. U-Pb isotopic dating using SHRIMP II method reveals that the metamafic rocks were formed at 274.7± 3.9 and 279.8± 3.6 Ma. The metamafic rocks mostly show N-MORB-typed rare earth element patterns and are enrichment in large-ion lithophile elements, indicating that they are probably derived from partial melting of a depleted mantle in a back-arc basin. Our new data, together with recent studied results on Paleozoic ophiolitic fragments suggest the Paleo-Tethys Ocean in Central Qiangtang opened at Cambrian and widened between Ordovician and Devonian. Northward subduction started in the Late Devonian–Early Carboniferous and a back-arc basin developed during Permian.

关键词： Tibet Longmuco-Shuanghu-Lancang suture zone metamafic rock zircon SHRIMP U-Pb dating geochemistry

3D visualization model and key techniques for digital mine

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中国有色金属学会会刊：英文版 2011年第S3期21卷 748-752页

作者： JIN Bao-xuan1,FANG Yuan-min2,SONG Wei-wei2 1. Yunnan Provincial geomatics Centre, Kunming 650034, China 2. Faculty of land Resource Engineering, Kunming University of science and Technology, Kunming 650093, China [a] Yunnan Provincial geomatics Centre Kunming 650034 China [b] Faculty of land Resource Engineering Kunming University of Science and Technology Kunming 650093 China

Digital mine is the inevitable outcome of the information processing, and is also a complicated system engineering. Firstly, for the 3D visualization application of the digital mine, the ground and underground integrative visualization framework model was proposed based on the mine entity database. So, the visualization problem was availably resolved, as well as the professional analytical ability was improved. Secondly, aiming at the irregularities, non-uniformity, dynamics of mine entities, mix modeling method based on the entity character was put forward, in which 3D expression of mine entities was realized. Lastly, the 3D visualization project for a copper mine was experimentally studied. Satisfactory results were acquired, and the rationality of visualization model and feasibility of 3D modeling were validated.

关键词： digital mine three dimension visualization framework model spatial data modeling

Forces Driving Changes in Cultivated land and Management Countermeasures in the Three Gorges Reservoir Area,China

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Journal of Mountain science 2013年第1期10卷 149-162页

作者： CAO Yin-gui BAI Zhong-ke ZHOU Wei WANG Jing school of land science and Technology China University of Geosciences Key Laboratory of land Reconsolidation and Rehabilitation Ministry of Land and Resources Key Laboratory of land Use Ministry of Land and Resources

The Three Gorges project accelerates economic development in the Three Gorges Reservoir *** paper aimed to investigate the distribution,changes and features of cultivated land in this area,analyze the forces driving the changes in cultivated land area,and propose the countermeasures for cultivated land *** matrix was used to analyze the features of cultivated land changes,and quantitative analysis and qualitative analysis were adopted to research the driving forces according to the features of cultivated land *** land in the Three Gorges Reservoir Area mainly lay to the northwest of the Yangtze River,especially the upper *** areas of cultivated land increased from 1996 to 1999,then decreased from 2000 to 2006,and finally increased again from 2007 to *** important forces driving changes in cultivated land included government policies,employment and food security,increasing construction land,agriculture structure adjustment,land rearrangement,*** cultivated land management,firstly,it is necessary to insist on the principle of cultivated land protection,standardize land exploitation and strictly restrict the transformation of cultivated land into non-farming ***,land rearrangement must be implemented,which can not only increase the area of the cultivated land,but also improve the quality of the cultivated ***,it is feasible to intensify eco-agriculture construction to increase the quantity and quality of cultivated ***,it is helpful to improve the traditional agriculture production methods to promote cultivated land ***,it is important to propagandize cultivated land protection and realize the enormous pressure of cultivated land shortage,making more people obligated to protect cultivated land.

关键词： land use change Driving force Management countermeasure Cultivated land Three Gorges Reservoir Area

UAV navigation system using line-based sensor pose estimation

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Geo-Spatial Information science 2018年第1期21卷 2-11页

作者： Julien Li-Chee-Ming Costas Armenakis Department of Earth and Space science and Engineering Geomatics EngineeringLassonde School of EngineeringYork UniversityTorontoCanada

This work presents a mapping and tracking system based on images to enable a small Unmanned Aerial Vehicle(UAV)to accurately navigate in indoor and GPS-denied outdoor environments.A method is proposed to estimate the UAV’s pose(i.e.,the 3D position and orientation of the camera sensor)in real-time using only the on-board RGB camera as the UAV travels through a known 3D environment(i.e.,a 3D CAD model).Linear features are extracted and automatically matched between images collected by the UAV’s onboard RGB camera and the 3D object *** matched lines from the 3D model serve as ground control to estimate the camera pose in real-time via line-based space *** results demonstrate that the proposed modelbased pose estimation algorithm provides sub-meter positioning accuracies in both indoor and outdoor *** is also that shown the proposed method can provide sparse updates to correct the drift from complementary simultaneous localization and mapping(SLAM)-derived pose estimates.

关键词： Pose estimation modelbased tracking navigation GPS-denied environment

Grid graph-based large-scale point clouds registration

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International Journal of Digital Earth 2023年第1期16卷 2448-2466页

作者： Yi Han Guangyun Zhang Rongting Zhang school of geomatics science and Technology Nanjing Tech UniversityNanjingPeople's Republic of China

Automatic registration of unordered point clouds is the prerequisite forurban reconstruction. However, most of the existing technologies stillsuffer from some limitations. On one hand, most of them are sensitive tonoise and repetitive structures, which makes them infeasible for theregistration of large-scale point clouds. On the other hand, most of themdealing with point clouds with limited overlaps and unpredictablelocation. All these problems make it difficult for registration technology toobtain qualified results in outdoor point cloud. To overcome theselimitations, this paper presents a grid graph-based point cloud registration(GGR) algorithm to align pairwise scans. First, point cloud is divided into aset of 3D grids. We propose a voting strategy to measure the similaritybetween two grids based on feature descriptor, transforming thesuperficial correspondence into 3D grid expression. Next, a graphmatching is proposed to capture the spatial consistency from putativecorrespondences, and graph matching hierarchically refines thecorresponding grids until obtaining point-to-point *** experiments demonstrated that the proposed algorithmobtains good performance in terms of successful registration rate, rotationerror, translation error, and outperformed the state-of-the-art approaches.

关键词： Point cloud alignment scan matching graph algorithms reconstruction

An analysis of close approaches and probability of collisions between LEO resident space objects and mega constellations

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Geo-Spatial Information science 2022年第1期25卷 104-120页

作者： Yan Zhang Bin Li Hongkang Liu Jizhang Sang school of Geodesy and geomatics Wuhan UniversityWuhanChina

With the undergoing and planned implementations of mega constellations of thousands of Low Earth Orbiting(LEO)satellites,space will become even more congested for satellite *** enduring effects on the long-term space environment have been investigated by various researchers using debris environment *** paper is focused on the imminent short-term effects of LEO mega constellations on the space operation environment concerned by satellite owners and *** effects are measured in terms of the Close Approaches(CAs)and overall collision *** of using debris environment models,the CAs are determined from integrated orbit positions,and the collision probability is computed for each CA considering the sizes and position covariance of the involving *** obtained results thus present a clearer picture of the space operation safety environment when LEO mega constellations are *** mega constellations are simulated,including a Starlink-like constellation of 1584 satellites,four possible generic constellations at altitudes between 1110 km and 1325 km,and three constellations of 1584 satellites each at the altitudes of 650 km,800 km,and 950 km,respectively,where the Resident Space Object(RSO)spatial density is the *** increases in the number of CAs and overall collision probability caused by them are really *** results suggest that highly frequent orbital maneuvers are required to avoid collisions between existing RSOs and constellation satellites,and between satellites from two constellations at a close altitude,as such the constellation operation burden would be very *** study is not only useful for satellite operators but a powerful signal for various stakeholders to pay serious attention to the development of LEO mega constellations.

关键词： Resident space object mega constellation close approach collision probability

The applications of robust estimation method BaySAC in indoor point cloud processing

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Geo-Spatial Information science 2016年第3期19卷 182-187页

作者： Zhizhong Kang school of land science and Technology China University of GeosciencesBeijingChina

Based on Bayesian theory and RANSAC,this paper applies Bayesian Sampling Consensus(BaySAC)method using convergence evaluation of hypothesis models in indoor point cloud *** implement a conditional sampling method,BaySAC,to always select the minimum number of required data with the highest inlier *** the primitive parameters calculated by the different inlier sets should be convergent,this paper presents a statistical testing algorithm for a candidate model parameter histogram to compute the prior probability of each data ***,the probability update is implemented using the simplified Bayes’*** performances of the BaySAC algorithm with the proposed strategies of the prior probability determination and the RANSAC framework are compared using real *** experimental results indicate that the more outliers contain the data points,the higher computational efficiency of our proposed algorithm gains compared with *** results also indicate that the proposed statistical testing strategy can determine sound prior inlier probability free of the change of hypothesis models.

关键词： 3D indoor modeling robust estimation RANSAC BaySAC point cloud registration fitting of point cloud