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Journal of Geographical sciences 2001年第2期11卷 127-139页

作者： ZHANG Guo-ping~1, ZHANG Zeng-xiang~1, LIU Ji-yuan~2.(1. Institute of remote sensing Application, CAS, Beijing 100101,{2. 2. Institute of Geographic sciences and Natural Resources Research, CAS, Beijing 100101,{2.) Institute of remote sensing Application CAS Institute of Geographic sciences and Natural Resources Research CAS

Based on remote sensing and geographic information system, the spatial distribution of nation-wide wind erosion is studied, and the 1∶100 000 national map of soil erosion by wind in{2. is made. Wind speed, soil dryness,NDVI, soil texture and the slope of land surface are the key factors to wind erosion. The relations between wind erosion and each factor are discussed. The method of principal component is used to pick up the information included in the five factors, and the wind erosion dynamic index (WEDI) is established. Its comparison with theRS/GIS derived data shows thatWEDI can reflect the potential capacity of soil erosion by wind. The dynamic process of the wind erosion is studied to reveal the distribution of the most intense wind erosion regions and the dominant factors in these regions. All these studies may greatly help the mitigation of wind erosion of soil.

关键词： remote sensing geographic information system wind erosion of soil desertification control in china WEDI

A common sense geographic knowledge base for GIR

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science china(Technological sciences) 2008年第S1期51卷 26-37页

作者： ZHANG Yi,GAO Yong,XUE LuLu,SHEN Si & CHEN KaiChen Institute of remote sensing and Geographic Information System,Peking University,Beijing 100871,{2. 1. Institute of remote sensing and Geographic Information System Peking University Beijing 100871 China

As background knowledge of geographic information retrieval (GIR),the gazetteers have their limitations. In this paper we propose to develop and implement a com-mon sense geographic knowledge base (CSGKB) instead of the gazetteers. We define that CSGKB is concerned with the representation of geographic knowledge in human brain and the simulation of geographic reasoning in daily life. Traditional geographic information system (GIS) is based on the model of map with its data based on geographic coordinates and its computation based on geometry. However,CSGKB,which is made up of geographic features and relationships and is based on qualitative spatio-temporal reasoning,can be viewed as the direct model of geographic world. This paper also discusses the characters of CSGKB and pre-sents its structure which is composed of knowledge base,inference engine,geo-graphic ontology and learner. The applications using CSGKB include geographic information retrieval (GIR),natural language processing (NLP),named entity rec-ognition (NER),Semantic Web,etc. At present,our work focuses on the design of geographic ontology and the implementation of the CSGKB knowledge base. In this paper we describe the CSGKB ontology structure,top ontology,geographic loca-tion ontology,spatial relationship ontology,and domain ontologies. Finally,we in-troduce the current state of implementation of CSGKB and give an outlook on our future researches.

关键词： geographic information retrieval common sense geographic knowledge base geographic ontology

Natural eco-environmental evaluation of eastern Qinghai-Tibet Plateau using RS and GIS

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Journal of Geographical sciences 2002年第3期12卷 283-288页

作者： YANG Shengtian, LIU Changming, YANG Zhifeng, SUNRui, ZHOU Xiaodong(1. Inst. of Environmental sciences, Beijing Normal University, Beijing 100875,{2. 2. Dept. of Resources and Environmental science, Beijing Normal University, Beijing 100875,china) Inst. of Environmental sciences Beijing Normal University 北京 100875 Dept. of Resources and Environmental science Beijing Normal University 北京 100875

The impact of interbasin water transfer on environment is very significant. The affected area of the west route scheme of the South to North Water Transfer Project in china (SNWT) is located in the eastern Tibetan Plateau, where the altitude is high with frigid eco-environment. In this article, remote {2. and GIS are applied to analyze the natural environment and the natural environment index is established to express the natural conditions of the study area. After the natural environment index is divided into four grades and the features of each grade are analysed, some results are obtained for reference in environmental assessment of the west route of SNWT.

关键词： Qinghai-Tibet Plateau environmental assessment remote sensing GIS

Evolution of a coastal upwelling event during summer 2.04.in the southern Taiwan Strait

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Acta Oceanologica Sinica 2011年第1期30卷 1-6页

作者： ZHANG Caiyun HONG Huasheng HU Chuanmin SHANG Shaoling state key {2. for Marine Environmental science College of Oceanography and Environmental Sciences Xiamen University Xiamen 361005 China College of Marine science University of South Florida St. Petersburg USA

A coastal upwelling event in the southern Taiwan Strait （STWS） was investigated using intensive cruise surveys （four repeated transects in a month） and satellite data in July and early August 2.04. The extensive upwelling-associated surface cold water was first observed in early July （-2.0×10a km2. along the STWS coast. Then, the cold surface water reduced in size by -50% with decreased chlorophyll concentrations after 15 days, indicating the weakening of the upwelling event. At the end of July, the cold surface water disappeared. The temporal variations of the surface cold water and the 3-D hydrography around Dongshan Island are thought to be mainly attributed to the weakened upwelling-favorable southwestern wind, the asymmetric spatial structure of the wind field and the intrusion of warm water from the northern South china Sea.

关键词： coastal upwelling evolution SST ocean color remote sensing Taiwan Strait

Multi-channel SAR imaging based on distributed compressive sensing

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science china(Information sciences) 2012年第2期55卷 245-259页

作者： LIN YueGuan1,2.3,ZHANG BingChen1,2.JIANG Hai1,2.3,HONG Wen1,2.& WU YiRong1,2.1National key laboratory of {2. and Technology on Microwave Imaging,Beijing 100190,china 2.nstitute of Electronics,Chinese Academy of {2.s,Beijing 100190,china 3Graduate University of Chinese Academy of {2.s,Beijing 10004.,china 1. National key laboratory of {2. and Technology on Microwave Imaging Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The rapid development of compressive sensing(CS)shows that it is possible to recover a sparse signal from very limited *** aperture radar(SAR)imaging based on CS can reconstruct the target scene with a reduced number of collected samples by solving an optimization *** multi-channel SAR imaging based on CS,each channel requires sufficient samples for separate imaging and the total number of samples could still be *** propose an imaging algorithm based on distributed compressive sensing(DCS)that reconstructs scenes jointly under multiple ***-channel SAR imaging based on DCS not only exploits the sparsity of the target scene,but also exploits the correlation among *** requires significantly fewer samples than multi-channel SAR imaging based on *** multiple channels offer different sampling rates,DCS joint processing can reconstruct target scenes with a much more flexible allocation of the number of measurements offered by each channel than that used in separate CS processing.

关键词： synthetic aperture radar multi-channel synthetic aperture radar compressive sensing distributed compressive sensing

Using soil surface gray level to determine surface soil water content

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science china Earth sciences 2010年第10期53卷 1527-1532页

作者： ZHU YuanJun1,2.WANG YunQiang1,2.& SHAO MingAn1,2.1 state {4. {2. of Soil Erosion and Dryland Farming on Loess Plateau,Institute of Soil and Water Conservation,Northwest A & F University,Yangling 712.00,china 2.Institute of Soil and Water Conservation,Chinese Academy of sciences & Ministry of Water Resources,Yangling 712.00,china 1. state key {2. of Soil Erosion and Dryland Farming on Loess Plateau Institute of Soil and Water Conservation Northwest A & F University Yangling 712100 China2. Institute of Soil and Water Conservation Chinese Academy of Sciences & Ministry of Water Resources Yangling 712100 China

How to determine surface soil water content(SWC) quickly and accurately is fundamental in studying eco-hydrological processes and their *** we use laboratory experiments to determine surface SWC using soil surface gray level(SGL) values.A negatively exponential relationship exists between SGL and SWC,i.e.,SGL increases with the decrease of *** can be estimated based on initial SGL value(surface gray level when SWC=0),SWC,and a surface roughness coefficient characterized by mean soil particle *** variation range of SGL was larger than that of SWC,indicating that changes in SWC were enhanced in SGL,and that SGL would thus be sensitive to changes in soil *** the 95% confidence level,SWC can be determined by using the relationship between SWC and SGL established by the *** determination of SWC has a high precision when SWC was between dry and saturated.

关键词： Loess Plateau soil water remote sensing surface roughness

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扬州市区京杭大运河水污染可视化模拟研究

系统仿真学报 2009年第12期21卷 3653-3657,3661页

作者：徐丙立林珲龚建华臧永强黄明祥太空与地球信息科学研究所香港中文大学中国香港中国科学院遥感应用研究所遥感科学国家重点实验室北京100101

以京杭大运河扬州市区段为研究对象,根据其水文特征选定了一维和二维水质模型。研究了如何实现污染时空分布的可视化模拟。详细讲述了可视化模拟的几个关键技术,即基本框架、河流栅格数据提取与叠加显示、水质模型的数值化处理与集成、... 详细信息

以京杭大运河扬州市区段为研究对象,根据其水文特征选定了一维和二维水质模型。研究了如何实现污染时空分布的可视化模拟。详细讲述了可视化模拟的几个关键技术,即基本框架、河流栅格数据提取与叠加显示、水质模型的数值化处理与集成、多点排污计算与颜色匹配、污染曲线绘制及多时相历史污染再现。开发河流水污染可视化模拟系统,对扬州市区京杭大运河真实数据和假设数据分别模拟,效果良好。创新点在于将地理信息和专业的水污染模型无缝集成,并将数据、模型计算和结果表达集成在统一的实时可视化平台中。

关键词：河流水污染可视化模拟

Architecture and key technologies of grid geographic information system

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science china(Technological sciences) 2008年第S1期51卷 102-113页

作者： FANG Yu,HUANG Zhou,CHEN Bin,WU Lun & YIN DaFei Institute of remote sensing and Geographic Information System,Peking University,Beijing 100871,{2. Institute of remote sensing and Geographic Information System Peking University Beijing 100871 China

The highly efficient and stable collaborative computation platform for geospatial information can be constructed on the basis of Grid computing technology,com-bined with Peer-to-Peer (P2.) computing technology and geospatial database technology. This paper proposed the architecture and key technologies of the Grid GIS (Geographic Information System) incorporated with P2. structure,and corre-spondingly a Grid GIS prototype named Nebula was designed and then imple-mented. Nebula is a suite of middleware for geospatial Grid computing,which could be deployed onto various service nodes in network. Based on Grid protocols and infrastructure,Nebula provides invocation interfaces to users in form of Grid services. By using P2. message based communication mechanism,complex geospatial computation tasks could be accomplished by Nebula in a collaborative way. This paper introduced Nebula's architecture and key modules,and according to experimental data,we discussed the Grid GIS's advantages,application scenar-ios and future directions.

关键词： Grid GIS distributed geospatial computing Peer-to-Peer computing

INVESTIGATION OF VORTEX SHEDDING INDUCED HYDRODYNAMIC VIBRATION IN VORTEX STREET FLOWMETER

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Chinese Journal of Mechanical Engineering 2001年第4期14卷 310-313页

作者： Fu Xin,Xu Bing,Yang Huayong (state key {2. of Fluid Power Transmission and Control,Zhejiang University) 浙江大学流体传动及控制国家重点实验室浙江

Vortex street flowmeter has been used in steady flow measurement for about three decades The benefits of this type of flowmeter include high accuracy,good linearty,wide measuring range,and excellent reliability However,in unsteady flow measurement,the pressure disturbance as well as the noise from the system or surrounding can reduce the signal to noise ratio of the flowmeter seriously Aimed to use vortex street flowmeters in unsteady flow measurement,the characteristics of the vortex shedding induced hydrodynamic vibration around the prism bluff body in a vortex street flowmeter are investigated numerically and by expriments The results show that the hydrodynamic vibrations with 180° phase shift occur at the axisymmetric points of the channel around the bluff body The most intense vibration occurs at the points on the lateral faces close to the base of the prism The results provide therefore a useful reference for developing an anti interference vortex flowmeter using the different ial sensing technique.

关键词： Vortex street flowmeter Vortex shedding induced hydrodynamic vibration Unsteady flow measurement Anti-interference performance