Characteristics and progress of land use/cover change research during 1990–2018     

He  Chunyang  Zhang  Jinxi  Liu  Zhifeng  Huang  Qingxu 《地理学报(英文版)》2022,32(3):537-559

Journal of Geographical Sciences - Land use/cover change (LUCC) is the foundation and frontier for integrating multiple land surface processes. This paper aims to systematically review LUCC...  相似文献   

Multipath mitigation via component analysis methods for GPS dynamic deformation monitoring   总被引：1，自引：0，他引：1  

Wujiao Dai  Dawei Huang  Changsheng Cai 《GPS Solutions》2014,18(3):417-428

Multipath is one of the main error sources in high-precision global positioning system (GPS) dynamic deformation monitoring, as it is difficult to be mitigated by differencing between observations. In addition, since a specific frequency threshold value between multipath and deformation signals may not exist, multipath is usually inseparable from the low-frequency vibration signal using conventional frequency-domain filter methods. However, the multipath repeats in two sidereal days when the surroundings of a GPS antenna remain unchanged. This characteristic can be exploited to model and thus mitigate multipath effectively in dynamic deformation monitoring. Unfortunately, a major issue is that the degree of repeatability decreases as the interval between first day and subsequent days increases. To overcome this problem, we develop a new sidereal filtering referred to as reference EMD-ICA (EMD-ICA-R), where empirical mode decomposition (EMD) and independent component analysis (ICA) are jointly used to model multipath and renew the reference multipath. For the successful implementation of the EMD-ICA-R, an a priori denoised multipath signal is needed as a reference. We further propose to use the principal component analysis (PCA) method to extract more accurate reference multipath signal and form a combined PCA-EMD-ICA-R approach. Simulation experiments with a motion simulation platform were conducted, and the testing results indicate that the proposed methods can mitigate the multipath by around 67 % when a reliable reference multipath signal is extracted from a static situation. Furthermore, simulation experiments with different deformation signals added into the coordinate time series of three consecutive days show that the two proposed methods are also effective in a dynamic situation. Since wavelet filtering is used to denoise the reference multipath signals in the new approaches, simulation experiments with several wavelet filters are tested, and the results indicate that the PCA-EMD-ICA-R approach can work well with various wavelet filters.  相似文献   

浅谈国土行业软件开发中项目管理制度的建立     

黄辉 《国土资源信息化》2014,(2)

随着信息技术的发展和信息化程度的不断提高,国土行业的软件开发活动越来越多。本文在综合考虑本行业软件开发中面临问题的基础上,融合项目管理的理论成果,积极探索在国土行业的软件开发中建立项目管理制度,从人员、流程、合同、质量和文档等方面对项目管理制度进行描述,并详细论述了项目管理制度的重要性,希望能为国土行业软件开发提供积极的启示和有益的借鉴。  相似文献   

基于Autonomy的国土资源档案知识挖掘与应用平台研究     

黄华坤 《国土资源信息化》2014,(4):30-34

本文在分析大数据背景下国土资源信息化面临的挑战及国土资源档案数据现状的基础上,提出基于Autonomy知识与服务架构,重点阐述架构的三个组成部分：数据采集平台、本体构建与分析平台、数据处理平台,介绍了基于Autonomy Idol的应用功能设计实例。探讨海量国土资源档案数据管理与应用的新方式,为国土资源数据档案的管理提供大数据支持的理论基础。  相似文献   

大数据时代的国土资源档案创新管理研究   总被引：1，自引：0，他引：1  

黄华坤 《国土资源信息化》2014,(3):42-45

在大数据时代,以广东省国土资源档案集群服务平台建设为例,以“档案数据大集中、应用系统大集群、档案服务大平台”为总体工作思路,提出了“一个中心,两个集群、三个统一、四位一体”的国土档案管理一揽予解决方案,并对基于大数据的国土资源档案知识服务进行了初步研究,为我国国土资源档案行业在大数据时代信息化建设提供极具实践意义的经验。  相似文献   

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刘峡  傅容珊  郑勇  黄建平  张祖胜  孙东平 《大地测量与地球动力学》2007,27(3):6-11

????????й?????????????????????????????????????????????????????????????????????????μ??й?????α? ?????GPS???????????????????????????????:??????????????????10???????й????????????????????????10??GPS?????????????????????;?????????????????????:??????????????????????????,??????????????????????????????????????,??????????????????????黡???????????????????????????,?????????????????????????????????????????????:1)?й?????????????????????????????????????????????????????????????????????????????;2)?Щ????????????????????????????????????й??????????????????  相似文献   

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梁全强  林淑冰  黄声明  刘序俨 《大地测量与地球动力学》2007,27(5):76-81

?????????г???????????????????????????????????????????????????????????????????????????α?????????黯???α?????????????????????????????????α?????????????????????????????????????е????????????,??????????α???????????  相似文献   

Effect of growing watershed imperviousness on hydrograph parameters and peak discharge     

Huang‐jia Huang  Shin‐jen Cheng  Jet‐chau Wen  Ju‐huang Lee 《水文研究》2008,22(13):2075-2085

An increasing impervious area is quickly extending over the Wu‐Tu watershed due to the endless demands of the people. Generally, impervious paving is a major result of urbanization and more recently has had the potential to produce more enormous flood disasters than those of the past. In this study, 40 available rainfall–runoff events were chosen to calibrate the applicable parameters of the models and to determine the relationships between the impervious surfaces and the calibrated parameters. Model inputs came from the outcomes of the block kriging method and the non‐linear programming method. In the optimal process, the shuffled complex evolution method and three criteria were applied to compare the observed and simulated hydrographs. The tendencies of the variations of the parameters with their corresponding imperviousness were established through regression analysis. Ten cases were used to examine the established equations of the parameters and impervious covers. Finally, the design flood routines of various return periods were furnished through use of approaches containing a design storm, block kriging, the SCS model, and a rainfall‐runoff model with established functional relationships. These simulated flood hydrographs were used to compare and understand the past, present, and future hydrological conditions of the watershed studied. In the research results, the time to peak of flood hydrographs for various storms was diminished approximately from 11 h to 6 h in different decrements, whereas peak flow increased respectively from 127 m³ s^?1 to 629 m³ s^?1 for different storm intensities. In addition, this study provides a design diagram for the peak flow ratio to help engineers and designers to construct hydraulic structures efficiently and prevent possible damage to human life and property. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Characteristics and distribution of clay minerals and their effects on reservoir quality: Huagang Formation in the Xihu Sag,East China Sea Basin     

X. L. Sun  X. G. Zhang  J. L. Lin  Z. X. Zhao  D. W. Huang 《Australian Journal of Earth Sciences》2013,60(8):1163-1174

Abstract

The characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats.  相似文献   

The Remediation of Perchloroethylene Contaminated Groundwater by Nanoscale Iron Reactive Barrier Integrated with Surfactant and Electrokinetics     

Shin-Shian Chen  Yi-Chu Huang  Tzu-Yen Kuo 《Ground Water Monitoring & Remediation》2010,30(4):90-98

In this study, nanoscale zero-valent iron (NZVI) particles were synthesized and utilized to integrate with surfactant and electrokinetics for the remediation of perchloroethylene (PCE). The average particle diameter and specific surface area of the lab-synthesized iron particles were 109.3 nm and 129.7 m² g^–1, respectively. Experiments were performed in a glass sandbox to simulate the transport and degradation of PCE in the aquifer. The results of the transport tests revealed that the PCE concentrations at the bottom layer was higher than those at the mid and upper layers, and that the surfactant Tween 80 showed its conspicuous mobilization for PCE in the aquifer. As the results of the degradation tests showed, NZVI activity could be promoted by electrokinetics that enhanced the remediation performance of PCE contaminated groundwater by the NZVI reactive barrier. Chlorinated byproducts were not detected during the degradation tests, that is, PCE was completely dechlorinated by NZVI in the reactive barrier. The information collected from this study will be useful for further application of the NZVI reactive barrier system to remediate the aquifers contaminated by the chlorinated solvents.  相似文献