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水土保持学报 2002年第6期16卷 43-45,75页

作者：沈大勇马蔼乃毛善君杨萍北京大学遥感与地理信息系统研究所北京100871 北京大学信息科学中心北京100871

阐述国内外坡面土壤水蚀建模发展历程,然后分别论述经验模型、概念模型、物理模型以及水蚀遥感信息模型的发展历程,最后比较各类模型优缺点。

关键词：坡面水蚀水蚀遥感信息模型

Spatial Distribution of Land Cover and Vegetation Activity along Topographic Gradient in an Arid River Valley, SW china

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Journal of Mountain Science 2009年第3期6卷 274-285页

作者： LIU Wen XU Xianli LUO Jiancheng SHEN Zhanfeng ZHONG Qiuhai Department of Automatic Control School of Automation Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Institute of Remote sensing Applications Chinese Academy of Sciences Beijing 100101 China Centre for Hydrology Micrometeorology and Climate Change Department of Civil and Environmental Engineering University College Cork Cork Ireland

Anthropogenic activities have become more and more important in characterizing the landscape, but their impacts are still restricted by natural environments. This paper discusses the interactions of anthropogenic activity, vegetation activity and topography through describing the spatial distribution of land cover and vegetation activity (represented by Normalized Difference Vegetation Index, NDVI) along topographic gradient in a mountainous area of southwestern china. Our results indicate that the existing landscape pattern is controlled by anthropogenic activities as well as topographic factors. Intensive anthropogenic activities mainly occur in areas with relatively low elevation, gentle and concave slopes, as these areas are easy and convenient to attain for human. Because of the destruction by human, some land cover types (mainly grassland and shrub) are only found in relatively harsher environments. This study also finds that topographic wetness index (W) used in other places only reflects runoff generation capacity, but not indicate the real spatial pattern of soil water content in this area. The relationships between NDVI and W, and NDVI and length slope factor (LSF) show that runoff and erosion have complex effects on vegetation activity. Greater values of W and LSF will lead to stronger capacity to produce runoff and transport sediment, and thereby increase soil water content and soil deposition, whereas beyond a certain threshold runoff and erosion are so strong that they would destruct vegetation growth. This study provides information needed to successfully restore native vegetation, improve land management, and promote sustainable development in mountainous areas, especially for developing regions.

关键词： Vertical distribution of land cover Anthropogenic activity Vegetation activity Environmental variability china

An ecological hydraulic radius approach to estimate the instream ecological water requirement

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Progress in Natural Science:Materials International 2007年第3期17卷 320-327页

作者： LIU Changming and MEN Baohui ( Key Laboratory of Water Cycle and Related Land Surface Process, Institute of geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, {2. Key Laboratory of Water and Sediment Sciences, Ministry of Education & Water Sciences College, beijing Normal {4., beijing 100875, {2. Department of Hydraulic and Hydropower Engineering, North {2. Electric Power {4., beijing 102.06, {2.) [a]Key Laboratory of Water Cycle and Related Land Surface Process Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China [b]Key Laboratory of Water and Sediment Sciences Ministry of Education & Water Sciences Gllege Beijing Noirnal University Beijing China [c]Departhent of Hydraulic and Hydropower Engineering North China Elecfric Power University Beijing China

This essay defines the concepts of ecological flow velocity as well as ecological hydraulic radius (EHR) and proposes an ecological hydraulic radius approach (EHRA) which considers both the watercourse information (including hydraulic radius, roughness coefficient and hydraulic gradient) and the required stream velocity necessary for maintenance of certain ecological functions all together. The key parameter of EHRA is to fix the watercourse cross-sectional flow area corresponding to EHR, by which the relation between parabola shaped cross-sectional flow area and hydraulic radius is deduced. The EHRA not only meets the requirement of flow velocity for adequate fish spawning migration, but also is applicable to the ecological flows in regard with other ecological issues (such as the calculation of the instream flow requirements for transporting sediment and for pollution self-purification, etc.). This essay has illuminated the computational process taking the estimation of ecological water requirement of Zhuba Hydrologyical Station watercourse in Niqu branch of the Yalong River as an example. Additionally, we compare EHRA with Tennant approach. The result shows that the Zhuba Hydrological Station ecological water requirement calculated by EHRA lies between the minimum and favorable ecological water requirement calculated by the Tennant approach. This is due to the fact that the ecological flow velocity (such as the fish spawning migration flow velocity) was taken into consideration, producing results applicable to the practical situation.

关键词： ecological flow flow velocity cross-sectional flow area ecological hydraulic radius (HER) instreamecological water requirement.

Approximation for a scheduling problem with application in wireless networks

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Science china Mathematics 2010年第6期53卷 1643-1655页

作者： ZHU QingHua & LI DeYing Key Laboratory of Data Engineering and Knowledge Engineering,MOE,School of information,Renmin university of {2.,beijing 100872.{2. 1. Key Laboratory of Data Engineering and Knowledge Engineering MOE School of Information Renmin University of China Beijing 100872 China

A network of many sensors and a base station that are deployed over a region is *** sensor has a transmission range,an interference range and a carrier sensing range,which are r,αr and βr,*** this paper,we study the minimum latency conflict-aware many-to-one data aggregation scheduling problem:Given locations of sensors along with a base station,a subset of all sensors,and parameters r,α and β,to find a schedule in which the data of each sensor in the subset can be transmitted to the base station with no conflicts,such that the latency is *** designe an algorithm based on maximal independent sets,which has a latency bound of(a+19b)R + Δb-a + 5 time slots,where a and b are two constant integers relying on α and β,Δ is the maximum degree of network topology,and R is the trivial lower bound of *** Δ contributes to an additive factor instead of a multiplicative one,thus our algorithm is nearly a constant(a+19b)-ratio.

关键词： approximation algorithm conflict-aware many-to-one data aggregation latency wireless sensor network

Geo-Agents: Design and Implement

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Wuhan university Journal of Natural Sciences 2001年第Z1期6卷 451-459页

作者： Ding Li, Qu Lei, Zhang Ying, Luo Ying wei, Wang Xiao lin, Xu Zhuo qun Department of Computer Science & Technology,peking university, beijing 100871, {2. Department of Computer Science & Technology Peking University Beijing 100871 China

Geo Agents, a multi agent system that processes distributed geospatial information and geospatial service was presented. Firstly, the requirement for distributed geographical information process was discussed, and the architecture of Geo Agents was introduced. Then in depth discussions were raised on agent system implementation, such as the basic agent, agent advertising, message passing, and collaborating. An example was also given to explain the problem solving process.

关键词： geographical information system (GIS) multi agent system (MAS) Geo Ggents communication collaboration

An Earth multi-body system elasticity and plasticity dynamics model

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Science china(Technological Sciences) 2006年第z2期49卷 23-29页

作者： ZHANG Qingxian, BI Siwen & GONG Huili Education Ministry Key Laboratory of Three-Dimensional information Extraction and Application, Capital Normal university, {2. 100037, china State Key Laboratory of Remote {4. Science, IRSA, Chinese Academy of Sciences, {2. 100101, china Capital Normal Univ Educ Minist Key Lab Dimens Informat Extract & App Beijing 100037 Peoples R China Chinese Acad Sci IRSA State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China

Research on the elasticity and plasticity dynamics of the Earth multi-body system, including the Earth multi-body system stratum-block's equivalent inertia force system and generalized inertia force, the Earth multi-body system stratum-block's equivalent inertia force system expressed with partial velocity and partial palstance, and Earth multi-body system generalized inertia force expressed with partial velocity and partial palstance. This research provides a theoretical foundation for further investigation of Earth multi-body dynamics.

关键词： Earth multi-body system, equivalent inertia force system, generalized inertia force, elasticity and plasticity, dynamics model.

A new method for stabilization of video images with large moving object

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A new method for stabilization of video images with large mo...

A novel spaceborne SAR wide-swath imaging approach based on Poisson disk-like nonuniform sampling and compressive sensing

2.07亚洲光电子会议电子成像与多媒体技术分会场

作者： Pengqi Gao, Lei Yan, Hongying Zhao Institute of Remote sensing & Geographic information System, {2. beijing Key Lab of Spatial information Integration & Its Application. beijing, 100871, china

Due to the affection of large moving object in the video image, the ordinary image stabilization algorithms can’t get precise motion vector of the image. In this paper, a new image stabilization method that explicitly deals with video images containing large moving object is given out. It detects a rough area containing moving object first. Then this area will be got rid of from source image. Finally, a feature area taken from the rest part is used to calculate the image motion. For the affection of moving object has been eliminated, motion vector’s precision of the image is improved greatly.

关键词： image stabilization moving object detection image processing

来源： cnki会议评论

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Science china(information Sciences) 2012年第8期55卷 1876-1887页

作者： SUN JinPing,ZHANG YuXi,TIAN JiHua&WANG Jun School of Electronic and information Engineering,Beihang university,{2. 100191,china 1. School of Electronic and information Engineering Beihang University Beijing 100191 China

Since the range swath width in the conventional single channel spaceborne synthetic aperture radar(SAR)is restricted by the system parameters,there is a trade-off between the azimuth resolution and the swath width in order to satisfy the Nyquist sampling *** this paper,we propose a novel spaceborne SAR wide-swath imaging scheme based on compressive sensing(CS)for the sparse *** proposed method designs a Poisson disk-like nonuniform sampling pattern in the azimuth direction,which meets the demand of wider swath by restricting the smallest time interval between any two azimuth samples,with the conventional sampling pattern preserved in the range *** a similar way to the processing procedure of spectral analysis(SPECAN)algorithm,the linear range migration correction(RMC)is realized while carrying out range compression,which can meet the demand for focusing with middle level *** reduce the computation load of CS reconstruction,we propose a novel fast reconstruction algorithm based on nonuniform fast Fourier transform(NUFFT),which greatly reduces the computation complexity from O(2. N)to O(4. log N).Experiment results validate the effectiveness of the proposed methods via the point target simulation and the Radarsat-1 raw data processing in F2.mode.

关键词： SAR wide-swath imaging compressive sensing NUFFT

Advances in estimation methods of vegetation water content based on optical remote sensing techniques

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Science china(Technological Sciences) 2010年第5期53卷 1159-1167页

作者： ZHANG JiaHua1,XU Yun1,YAO FengMei2.WANG PeiJuan1,GUO WenJuan1,LI Li1 & YANG LiMin3 1 Chinese Academy of Meteorological Sciences,beijing 100081,china 2.Graduated {2. of Chinese Academy of Sciences,beijing 10004.,china 3 USGS/EROS Data Center,South Dakota 57198,USA 1. Chinese Academy of Meteorological Sciences Beijing 100081 China2. Graduated University of Chinese Academy of Sciences Beijing 100049 China3. USGS/EROS Data Center South Dakota 57198 USA

Quantitative estimation of vegetation water content(VWC) using optical remote sensing techniques is helpful in forest fire as-sessment,agricultural drought monitoring and crop yield *** paper reviews the research advances of VWC retrieval using spectral reflectance,spectral water index and radiative transfer model(RTM) *** also evaluates the reli-ability of VWC estimation using spectral water index from the observation data and the *** on two main definitions of VWC-the fuel moisture content(FMC) and the equivalent water thickness(EWT),the retrieval accuracies of FMC and EWT using vegetation water indices are ***,the measured information and the dataset are used to estimate VWC,the results show there are significant correlations among three kinds of vegetation water indices(i.e.,WSI,NDⅡ,NDWI164.,WI/NDVI) and canopy FMC of winter wheat(n=4.).Finally,the future development directions of VWC detection based on optical remote sensing techniques are also summarized.

关键词： optical remote sensing vegetation water content estimation method water index FMC EWT radiative transfer model

Ontology-based analysis of multi-scale modeling of geographical features

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Science china(Technological Sciences) 2006年第z2期49卷 121-131页

作者： WANG Yanhui, LI Xiaojuan & GONG Huili Key Laboratory of Three-Dimensional information Acquisition and Application, Ministry of Education, Capital Normal university, {2. 100037, china {2. Key Laboratory of Resource Environment and GIS, Capital Normal university, {2. 100037, china Capital Normal Univ Minist Educ Key Lab Dimens Informat Acquisit & Applicat 3 Beijing 100037 Peoples R China Capital Normal Univ Beijing Key Lab Resource Environm Beijing 100037 Peoples R China Capital Normal Univ GIS Beijing 100037 Peoples R China

As multi-scale databases based on scale series of map data are built, conceptual models are needed to define proper multi-scale representation formulas and to extract model entities and the relationships among them. However, the results of multi-scale conceptual abstraction schema may differ, according to which cognition, abstraction and application views are utilized, which presents an obvious obstacle to the reuse and sharing of spatial data. To facilitate the design of unified, common and objective abstract schema views for multi-scale spatial databases, this paper proposes an ontology-based analysis method for the multi-scale modeling of geographical features. It includes a three-layer ontology model, which serves as the framework for common multi-scale abstraction schema; an explanation of formulary abstractions accompanied by definitions of entities and their relationships at the same scale, as well as different scales,which are meant to provide strong feasibility, expansibility and speciality functions; and a case in point involving multi-scale representations of road features, to verify the method's feasibility.

关键词： multi-scale representation, ontology-based analysis, multi-scale data modeling, hierarchical ontology.