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1.
LD2000 System with 3S and Multi—sensor 总被引：2，自引：0，他引：2
This paper introduces a car-borne road information collecting and updating system (LD2000) developed by Wuhan Technical University of Surveying and Mapping.This system is capable of collecting road network information and creating digital road network effectively by means of GPS,GIS and multi-sensor integration.The design and development of LD 2000 system are also presented in this paper. 相似文献
2.
Regional frequency analysis of extreme precipitation and its spatio-temporal characteristics in the Huai River Basin, China 总被引：1，自引：1，他引：0
With the increasing exposure of populations and economy to natural hazards, the spatio-temporal characteristics of extreme rainfall remain a key subject of study. Based on annual maximum rainfall (AM) and peaks over threshold rainfall series at 30 meteorological stations during 1960–2011 in the Huai River Basin (HRB), spatio-temporal characteristics of extreme rainfall are analyzed through regional frequency analysis method using L-moments. The accuracy and uncertainty analysis of quantile estimations are also carried out, and the regional and at-site frequency analyses are compared. Results indicate the following: (1) During 1960–2011, AM precipitation at 20 stations in the HRB shows an increasing trend, while at the other 10 stations, it shows a decreasing trend. And both the increased and decreased trends are not significant. (2) The HRB can be categorized into three homogeneous regions via cluster analysis. For both at-site and regional frequency analyses, the root mean square error values increase with the increase in return periods. The estimations are reliable enough for the return periods of less than 100 years. The quantile estimates of large return period from regional frequency analysis are more accurate and have smaller uncertainty than those from at-site frequency analysis. (3) Extreme precipitation in the HRB concentrates in the upstream of the Huai River and YiShuSi water system in the east of the HRB. Generally, the area with extreme precipitation, especially the upper reaches of the Huai River and Yimeng Mountain areas, also has large standard variations of extreme precipitation, which will increase the risk of natural hazards. 相似文献
3.
针对裂缝性油藏为裂缝-孔隙型双重介质且加热区内地层温度为非等温分布,在常规稠油油藏蒸汽吞吐加热半径计算模型的基础上,通过引入加热区前沿温度,构建了考虑地层温度为非等温分布的裂缝性稠油油藏蒸汽吞吐加热半径计算模型,并基于天然裂缝等效渗透率张量理论,将裂缝性油藏变换成等效各向同性油藏,最终推导出裂缝性稠油油藏蒸汽吞吐产能预测模型。以某裂缝性稠油油藏为例进行了计算,结果表明,本文产能预测模型计算结果与裂缝性双重介质热采数值模拟计算结果基本吻合,从而验证了本文模型的准确性。敏感性分析表明,蒸汽吞吐加热半径是加热区前沿温度的函数,加热半径随前沿温度的降低而增大,产量随裂缝孔隙度的增加而增大。 相似文献
4.
数字图像处理技术在钢坯在线检测系统中的应用 总被引：4，自引：0，他引：4
介绍了钢坯在线测宽测厚系统的基本原理和系统组成。同传统的接触式测量相比，本系统利用红外热成像，通过计算和寻找梯度最大值进行钢坯边缘检测，根据梯度对边缘进行亚像素细分，对钢坯宽度和左右厚度尺寸进行实时测量。提出了非接触式钢坯尺寸测量中一种新的边缘检测方法，并从理论和生产实践上证明了该方法的可行性和正确性。 相似文献
5.
提出了用方波对比传递函数ＣＴＦ评价ＣＣＤ像传感器像质的方法，给出了计算ＣＣＤ像传感器方波对比传递函数ＣＴＦ的公式，并着重分析讨论了ＣＣＤ像传感器的离散性对像质的影响。实验表明，理论分析结果与实验数据基本符合，为更精确地进行ＣＣＤ及其它离散器件的系统设计提供了理论依据 相似文献
6.
This paper describes the scanning assembly principle and construction of scanning assembly sample.The factors that affect assembly accuracy are analyzed.Threre are two steps in CCD focal plane scanning assembly.The first is rough assembly,In this paper,the moire fringe is introduced in judging assembly accuracy directly and accurately.The equation for optical transmission characterisitcs of CCD Moire fringes is presented.The measurement of Moire fringes can be completed when some conditions are satisfied.2D-assembly error can be obtained by using digital correlation filtering technique,Finally,the result of focal plane scanning assembly is presented.The result is in good accordance with theory. 相似文献
7.
在构建分布式水文模型与生物地球化学模型的耦合模型（DTVGM-CASACNP）及应用元胞自动机-马尔科夫（CA-Markov）土地利用预测模型基础上,以滦河流域为例分析气候变化、土地利用/覆被变化（LUCC）及CO2浓度升高对径流的影响。研究结果表明: DTVGM-CASACNP耦合模型以及CA-Markov模型在滦河流域均具有较好的适用性;气候变化与土地利用/植被覆盖变化对滦河流域径流的影响较CO2浓度升高的影响程度大;未来不同情景下滦河流域2020—2049年径流呈减小趋势,大部分情景下年径流较基准年减少,与非汛期相比,滦河流域未来汛期径流对不同情景更敏感,总体上在汛期径流相对基准年减少,而在非汛期径流相对基准年增加。 相似文献
8.
提高外资利用效率是实现中国外资利用模式从数量型向质量型战略转变的关键途径,具有重要的现实和理论意义。基于此理,本文引入DEA模型,选取劳动、资本、资金3 项投入指标和技术溢出、经济和社会产出3 项产出指标构建评价体系,对中国FDI利用效率的时空变化特征进行了实证分析。结果显示:①近10 年全国外资利用效率普遍偏低且变动幅度不大,外资利用技术效率>规模效率>综合效率。②中国外资利用效率空间分异的变化显著,由2000 年“大集中-小分散”与“大分散-小集中”并存空间分布特征转变为2009 年“大集中-小分散”的空间分布格局,且西部外资利用效率长期大于东部和中部地区,在全国规模收益递减和不变地区长期占主导地位;③外资利用技术效率和规模效率共同决定着综合效率,而技术效率的决定作用稍微较强。对于外资利用效率有待优化的地区应重视外资管理和引导外资从冗余地区逐步迁移,对外资流向和流量进行监控。 相似文献
9.
Separating the effects of climate change and human activities on runoff over different time scales in the Zhang River basin 总被引：2，自引：0，他引：2
Sidong Zeng Jun Xia Hong Du 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(2):401-413
Most studies on separating the effects of climate change and human activities on runoff are mainly conducted at an annual scale with few analyses over different time scales, which is especially essential for regional water resources management. This paper investigates the impacts of climate change and human activities on runoff changes at annual, seasonal and monthly time scales in the Zhang River basin in North China. Firstly, the changing trends and inflection point are analyzed for hydro-climatic series over different time scales. Then the hydrological modeling based method and sensitivity based method are used to separate the effects. The results show that the effect of climate change is stronger than that of human activities on annual runoff changes. However, the driving factors on runoff are different at seasonal scale. In the wet season, the effect of human activities on runoff, accounting for 57 %, is stronger than that of climate change, while in the dry season climate change is the dominant factor for runoff reduction and the contribution rate is 72 %. Furthermore, the effects of climate change and human activities on monthly runoff changes are various in different months. The separated effects over different time scales in this study may provide more scientific basis for the water resources adaptive management over different time scales in this basin. 相似文献
10.
基于夜光遥感和小区POI的住宅发展与经济增长的空间耦合研究 总被引：1，自引：0，他引：1
潘思东 《地球信息科学学报》2017,19(5):646-652
针对城市住宅业发展与其经济增长之间的单向或双向因果关系问题,有关学者利用宏观统计分析的方法得到了不同的结论。本文通过构建二者的时空数据集,在城市内部微观层面上剖析了二者的耦合联系及其空间差异性,以期在细尺度上解释二者之间的关系。本文选取郑州市作为研究区,提出了一种基于夜光遥感数据的GDP空间化估算方法,进而生成GDP时空数据集;基于住宅小区POI点数据对城市住宅进行空间密度估计,得到住宅小区的时空分布数据集;最后对GDP和住宅建设密度进行了空间互相关分析,探究住宅发展与经济增长像元尺度上的共变趋势。结果表明：与前人的宏观研究论断不同,耦合分析结果显示住宅业发展与经济增长之间的关系在城市内部具有空间差异性,两者既存在相互影响的区域,也存在无相关的区域;耦合协调关系极显著的区域约占两成,且主要位于市属区和县域中心区;耦合不显著和不相关的区域超过七成,大部分位于市属县域。 相似文献