共查询到20条相似文献，搜索用时 31 毫秒
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基于数据包络分析的中国沿海省市港口经济相对效率评价 总被引：3，自引：0，他引：3
港口经济对国民经济有巨大的拉动作用,对沿海省市港口经济进行有效性评价,掌握港口经济运行现状,对于未来港口经济的发展具有重要的意义.应用数据包络分析方法(DEA)对中国11个沿海省市2005年港口经济运行相对效率进行评价.结果表明:一些沿海省市港口经济发展存在着纯技术无效或者纯规模无效,一些沿海省市纯技术与纯规模均无效,最终导致综合运行效率欠佳.并根据评价结果针对具体情况进行了分析,进而对港口经济的可持续发展提出了建议. 相似文献
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基于高光谱数据的小麦叶绿素含量反演 总被引：18，自引：0，他引：18
近年来,遥感高光谱技术为获取农作物的某些生理化参数提供了丰富的数据来源。该文使用北京小汤山地区实验获取的小麦高光谱数据,应用偏最小二乘回归方法,建立了冬小麦冠层波谱与叶绿素含量的回归反演计算模型。研究结果显示:模型在350～1060nm波段具有较高的反演精度。本研究为应用高光谱数据反演冬小麦叶绿素含量提供了有效途径。 相似文献
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谱段设置是资源卫星传感器设计的关键技术之一。该文针对土地资源管理对资源卫星光谱分辨率的需求。详细分析了收集和采集的主要土地利用/覆被光谱数据的特征，从主要地物的光谱可分性出发，提出了满足土地资源管理需要的资源卫星传感器谱段设置方案，并利用机载成像光谱数据进行波段优选和在轨资源卫星数据的模拟验证，分类对比研究表明，该优化谱段模拟图像土地利用／覆被分类效果好于TM和CBERS-1影像。 相似文献
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基于WebMGIS的矿山安全实时监测集成系统及其应用 总被引：5，自引：0，他引：5
矿山安全实时监测对矿山安全与防灾减灾具有重要的意义。该文在分析当前国内矿山GIS(MGIS)、矿山安全监测系统(MSMS)研究与应用现状的基础上,指出MGIS与MSMS在企业网上进行集成的必要,提出了统一的时空框架下系统集成后的功能和总体结构,论述系统集成中的开发方法选择、时空数据组织、空间数据接口、数据库访问方法及页面更新等问题,最后对该系统在开滦林南仓的成功应用作了简要介绍。 相似文献
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Kriging方法在区域土壤水分估值中的应用 总被引：74，自引：9，他引：74
土壤水分的观测对于地表参数化的发展以及气候变化的研究有着重要的作用。本文对大尺度区域土壤水分的估值进行了尝试:采用1987年中国102个气象站点1米土层四个季节的土壤水分值作为样本,运用KRIGING方法,通过对半变异函数的计算和分析,得出了所研究7个采集日的拟合函数,发现均符合球状模型,对模型有关的参数进行了拟合。并将插值结果与距离反比法进行了对比性检验,同时给出了KRIGING方法的估值精度。检验结果表明平均相对误差和标准偏差均以距离反比法较小,以样本量较大的f时段为例对检验结果进行了深入分析。由此得出了KRIGING方法内插估值的优势和不足,简要给出了提高估值精度的可能方案。最后对中国东半部f时段的土壤水分值进行内插成图。 相似文献
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Marine mammals and marine birds perform diving to forage underwater. Recent technological advances have led to rapid progress in our understanding of diving behavior, but additional research is required into feeding behavior to determine the timing of prey ingestion, prey mass, and prey type. To achieve a comprehensive understanding of the foraging and diving behavior of these endotherms, it is essential to integrate information on feeding behavior with other data. The challenges involved in developing an appropriate research method have been addressed, and several methods have been tested and used in the field, including the stomach temperature method, the esophagus method for marine birds, the stomach temperature telemeter method for seals, and the beak magnet sensor method. In the present study, I review these methods, suggest the necessity of their further development in field studies, and propose a new practical method that involves the measurement of jaw movements underwater as an indicator of the feeding behavior of seals. 相似文献
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国际贸易中的隐含碳排放研究综述 总被引：7，自引：0，他引：7
通过总结最近国际上关于贸易隐含碳排放的研究进展,指出国际贸易对国家及全球的温室气体排放具有重要的影响。传统的基于领土范围的CO2排放统计方法极易歪曲一国CO2排放的真实情况,不仅会引起发达国家对发展中国家＂碳泄漏＂现象的发生,也会间接地导致全球CO2排放的增加。作为发展中国家的中国,由于对外贸易的快速发展及较高的能耗水平,事实上为国外,尤其为发达国家排放了数量巨大的CO2。中国不是其碳排放的唯一责任方。在未来的气候变化谈判中,国际贸易对国家及全球CO2排放的影响应被高度重视;发达国家应该在减少温室气体排放方面继续承担主导作用,同时也应该加大对发展中国家的先进生产技术的转让和财政支持;中国等发展中国家除了提高自身的生产效率和能源利用效率外,还应加强对贸易中隐含碳排放的研究,以可靠有利的数据为国家争取更大的发展空间。 相似文献
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针对大气环流形势,从天气系统的定义出发,面向气象业务MICAPS格点文件数据格式,在矢量旋转追踪法等值线分析的基础上,有序提取等值线的控制点。经过滤波、查找各等值线特性点、剔除异常点等处理,获取沙尘暴高空影响天气系统的基本节点。利用多种特征参量设计了方便可行的算法,完成了槽脊系统的数据构建、分析并确定其地理位置。通过对数据场数值结构分析,建立了确定闭合天气系统位置及其高、低性质的算法。使用Visual Basic语言,开发了相应的沙尘暴高空基本影响天气系统类别自动分析软件,为实现概念模型自动预报系统、提高沙尘暴业务预报现代化水平打下了基础。 相似文献
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基于CA模型的乌鲁木齐都市圈城市用地扩展模拟研究 总被引：4，自引：2，他引：2
借助CA模型技术,基于乌鲁木齐都市圈城市用地发展的特点,构建了模拟多个城市群体扩展的CA模型,重点对模型的转换规则进行了扩展,把用地适宜性约束、城市内部社会经济驱动、城市之间相互作用力、区域生态格局限制、城市发展规模有限这几个方面的作用机制融入到模型的规则制定中,通过宏观约束、中观调节、微观驱动3个层次逐步实现;为了使社会经济数据与CA模型中的空间数据相匹配,对社会经济数据进行了空间化表达;在历史数据的参照下,所构建的模型经过反复调试与修正,模拟结果达到了较为满意的效果;应用此模型模拟了经济优先、生态优先与规划优先3种不同情景下的城市用地扩展,对都市圈城市用地今后的发展起到重要的启示作用。 相似文献
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Yuanyuan Yang Shuwen Zhang Jiuchun Yang Liping Chang Kun Bu Xiaoshi Xing 《地理学报(英文版)》2014,24(4):746-766
Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects: (1) Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming. (2) Historical maps and pictures offer visual and spatial quantitative land-cover information. (3) Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types. (4) Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution. (5) Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects. 相似文献
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Land use planning and necessary supporting data are crucial to developing countries that are usually under severe environmental and demographic strains. Approaches and methods to map the variability of natural resources are important tools to properly guide spatial planning. In this paper, we describe a method to quickly map terrain at reconnaissance (1:250,000) and semi-detailed (1:50,000) levels. This method can be utilized as a basis for further land evaluation and land use planning in large territories. The approach was tested in the state of Michoacan, central-western Mexico, currently undergoing rapid deforestation and subsequent land degradation.Results at the reconnaissance level describe the geographic distribution of major landforms and dominant land cover, and provide a synoptic inventory of natural resources. Results at the semi-detailed level indicate how to nest individual landforms to major units and how they can be used to run procedures for land evaluation. If combined with appropriate socioeconomic data, governmental guidelines for land use planning can be formulated on the basis of reconnaissance and semi-detailed terrain analysis. 相似文献
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Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects:(1) Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming.(2) Historical maps and pictures offer visual and spatial quantitative land-cover information.(3) Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types.(4) Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution.(5) Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects. 相似文献
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靖学青 《云南地理环境研究》1997,9(1):18-22
随着时间的推移，沿边地区开放开发将不以人的意志为转移地发生形式上的转换，即边境国际贸易→边境出口加工企业→边境国际性区域经济合作，这种转换规律，是由利益机制驱动的。我国沿边地区在开放开发中出现的诸如沿边国际贸易不稳、发展缓慢等问题，就是因为沿边开放开发的形式转换，没有跟上边境经贸发展的步伐，沿边出口加工生产严重滞后的缘故，因此中国沿边地区应加快外向性产业实体建设，大力推进沿边开发形式的转换，以扭转当前的被动局面。 相似文献
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Improving maternal health is one of the Sustainable Development Goals. Hospital service areas (HSAs), which contain most hospitalization behaviors at the local scale, are crucial for health care planning. However, little attention has been given to HSAs for maternal care and the hierarchy structure. Considering Hubei, central China, as a case study, this study aims to fill these gaps by developing a method for delineating hierarchical HSAs for maternal care using a network optimization approach. The approach is driven by actual patient flow data and has an explicit objective to maximize the modularity. It also establishes the hierarchical structure of maternal care HSAs, which is fundamental for the planning of hierarchical maternal care and referral systems. In our case study, 45 secondary HSAs and 22 tertiary HSAs are delineated to achieve maximal modularity. The HSAs perform well in terms of indices such as the Localization Index and Market Share Index. Furthermore, there is a complementary relationship between secondary and tertiary hospitals, which suggests the need for referral system planning. This study can provide evidence for the validity of the HSA and the planning of maternal care HSAs in China. It also provides transferable methods for planning hierarchical HSAs in other developing countries. 相似文献
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Yihong Yuan Martin Raubal 《International journal of geographical information science》2014,28(3):496-520
The rapid development of information and communication technologies (ICTs) has provided rich data sources for analyzing, modeling, and interpreting human mobility patterns. This paper contributes to this research area by developing the Spatio-temporal Edit Distance measure, an extended algorithm to determine the similarity between user trajectories based on call detailed records (CDRs). We improve the traditional Edit Distance algorithm by incorporating both spatial and temporal information into the cost functions. The extended algorithm can preserve both space and time information from string-formatted CDR data. The novel method is applied to a large data set from Northeast China in order to test its effectiveness. Three types of analyses are presented for scenarios with and without the effect of time: (1) Edit Distance with spatial information; (2) Edit Distance with time as a factor in the cost function; and (3) Edit Distance with time as a constraint in partitioning trajectories. The outcomes of this research contribute to both methodological and empirical perspectives. The extended algorithm performs well for measuring low-resolution tracking information in CDRs, as well as facilitating the interpretation of user mobility patterns in the age of instant access. 相似文献
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问卷调查方法在中国人文地理学研究的应用 总被引：5，自引：1，他引：4
问卷调查方法是人文地理学微观研究的重要工具,在以人为本的城市发展理念影响下开始得到广泛应用。本文运用文献计量方法分析问卷调查方法在中国人文地理学研究的应用概况,同时以2013年北京宜居城市问卷调查为案例,重点阐述问卷调查过程的抽样方案设计思想,最后对问卷调查方法的主要应用领域进行回顾总结,以期促进问卷调查方法在中国人文地理学研究的科学规范应用。研究发现：问卷调查方法在中国人文地理学研究的应用逐渐增强,研究内容不断拓展与深化,研究区域涵盖不同空间尺度、并以微观尺度为趋势,研究方法以数理统计、GIS空间分析等定量方法为主,但对问卷抽样设计阐述却不够科学规范;通过2013年北京宜居城市问卷调查案例分析,强调对问卷收集方法、抽样方式和抽样框选取、样本量确定等内容所构成的抽样方案设计过程重视,以加强问卷调查数据的科学采集;问卷调查方法在时空行为、人居环境、城市社会、旅游行为和农户行为等主题展开大量应用实践,在此基础上对问卷调查方法研究框架进行总结,并提出国内问卷调查方法应用的改进方向。 相似文献
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Studies of land-use change often require the combination of socioeconomic survey data with spatially continuous maps of land-cover change. One approach is to define maps of land ownership, assuming that all land-use change can be attributed to the owners or managers of each parcel of land. Unfortunately, records of administrative boundaries between towns and villages are commonly unavailable in developing countries and prohibitively costly or time consuming to map for individual projects. However, point locations of the settlements themselves can be obtained easily from existing maps or remotely-sensed imagery. In this paper we compare three methods – circular buffers, unweighted Voronoi polygons (sometimes referred to as Thiessen polygons) and multiplicatively weighted Voronoi polygons – for estimating boundaries between villages in an agricultural landscape in West Africa. The benefits and limitations of each approach are discussed, and their accuracy assessed using 98 independently collected GPS coordinates of village boundaries. We present a novel method for generating and optimising weights for multiplicatively weighted Voronoi polygons using survey data of village sizes from a subset of villages. By using both spatial information and survey data from villages, we show that multiplicatively weighted Voronoi polygons outperform other methods of predicting village boundaries, and increase the correlation coefficient between surveyed village area and mapped areas from 0.18 to 0.68 compared with more commonly used unweighted Voronoi polygons. Our method of weighting Voronoi polygons can be implemented with data and software commonly available to researchers and non-governmental organisations. 相似文献