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471.
随着专题数据处理向着定量化、辅助决策方向发展,对专题数据处理数学模型提出了更多更高的要求。针对当前制图系统和GIS中数学模型(库)的重用性和可扩展性较差的问题,提出基于元算法的相关概念,并通过对专题数据处理数学模型的深入研究,建立了基于元算法的专题数据处理模型库,最后将该模型库应用到GIS中的专题地图制作中,取得了较好的实验效果。实践证明,基于元算法专题数据处理数学模型库不仅具有建库的高效性,而且具有管理的动态性和使用的灵活性,同时也充分说明基于元算法数学模型库系统具有较大的推广价值。 相似文献
472.
中国城镇职工基本养老保险基金区域差异及影响机理 总被引:2,自引:1,他引:1
缩小地区差距,实现基本养老保险全国统筹,有利于增进人民福祉、促进社会公平以及提升人民的幸福感。基于2007-2016年中国31省(市、自治区)面板数据,运用泰尔指数、探索性空间数据分析及地理探测器等方法,研究中国城镇职工基本养老保险基金区域差异和影响机理。研究表明:① 城镇职工基本养老保险基金支出总体和带间泰尔指数稳步下降,带内泰尔指数逐年上升;② 城镇职工基本养老保险基金累计结余空间分布差异明显。高值区和次高值区主要分布在东部地区,次低和低水平主要分布在西部地区和东北地区。③ GDP、参保人数、制度赡养率等7因素对基本养老保险基金区域差异影响大。同时,各因子叠加后影响体现为非线性增加或双因子增强。为此,应坚持统筹区域社会经济协调的发展理念,夯实缴费基数,确保应保尽保,分步推进基本养老保险全国统筹。 相似文献
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Land-cover change may affect water and carbon cycles when transitioning from one land-cover category to another (land-cover conversion, LCC) or when the characteristics of the land-cover type are altered without changing its overall category (land-cover modification, LCM). Given the increasing availability of time-series remotely sensed data for earth monitoring, there has been increased recognition of the importance of accounting for both LCC and LCM to study annual land-cover changes. In this study, we integrated 1,513 time-series Landsat images and a change-updating method to identify annual LCC and LCM during 1986–2015 in the coastal area of Zhejiang Province, China. The purpose was to quantify their contributions to land-cover changes and impacts on the amount of vegetation. The results show that LCC and LCM can be successfully distinguished with an overall accuracy of 90.0%. LCM accounted for 22% and 40.5% of the detected land-cover changes in reclaimed and inland areas, respectively, during 1986–2015. In the reclaimed area, LCC occurred mostly in muddy tidal flats, construction land, aquaculture ponds, and freshwater herbaceous land, whereas LCM occurred mostly in freshwater herbaceous land, Spartina alterniflora, and muddy tidal flats. In the inland area, both LCC and LCM were concentrated in forest and dryland. Overall, LCC had a mean magnitude of normalized difference vegetation index (NDVI) change similar to that of LCM. However, LCC had a positive effect and LCM had a negative effect on NDVI change in the reclaimed area. Both LCC and LCM in the inland area had negative impacts on vegetation greenness, but LCC resulted in larger NDVI change magnitude. Impacts of LCC and LCM on vegetation greenness were quantified for each land-cover type. This study provided a methodological framework to take both LCC and LCM into account when analyzing land-cover changes and quantified their effects on coastal ecosystem vegetation. 相似文献
478.
WANG Shaoqiang WANG Junbang ZHANG Leiming XIAO Zhishu WANG Feng SUN Nan LI Daiqing CHEN Bin CHEN Jinghua LI Yue WANG Xiaobo WANG Miaomiao 《资源与生态学报(英文版)》2019,10(2):105-111
Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China's ecological civilization construction. The national key research and development program “Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China”, launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation, some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle (UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods. 相似文献
479.
本文以福建罗源湾海域为重点研究区域,结合台风风暴潮数值模式,对不同强度、不同方向台风引起的风暴潮增(减) 水规律进行了数值模拟研究。通过对影响罗源湾海域的历史台风分析,确定了影响该区域的两种典型台风路径,即东南-西北移动 (NW-SE) 和南-北移动 (N-S) 路径。文中结果表明:在两种典型路径台风到达罗源湾海域时,罗源湾内的风暴增水达到极值,在超强台风 (中心气压及最大风速:945 hPa,55 km/h) 作用下,NW-SE 和 N-S 路径下增水极值分别为3.9 m 和 3.67 m。随着两种典型台风路径从湾外向湾内平移,湾内不同岸段的风暴增水表现出不同的规律:北岸和西岸增水逐渐增大且在典型台风路径过湾顶向西平移约 15 km 处达到最大;湾内南岸区域增水逐渐减小且在台风路径过湾口向湾外平移约 15 km 处达到最大;湾口站点增水极值随路径平移无明显变化。对于 N-S 典型路径方向,台风中心过罗源湾后有明显减水现象,且越靠近湾内的站点减水程度越大,超强台风作用下湾内西北角站点减水达 2.80m,而 NW-SE 路径的台风风暴减水现象不明显。 相似文献
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We selected a sample of nearby galaxies from the Sloan Digital Sky Survey Data Release 7(SDSS DR7) to investigate the variation of physical properties from the blue cloud to green valley to red sequence.The sample is limited to a narrow range in the color-stellar mass diagram. After splitting green valley galaxies into two parts—a bluer green valley(green 1) and a redder one(green 2) and three stellar mass bins,we investigate the variation of physical properties across the green valley region. Our main results are as follows:(i) The percentages of pure bulge and bulge-dominated/elliptical galaxies increase gradually from blue cloud to red sequence while the percentages of pure disk and disk-dominated/spiral galaxies decrease gradually in all stellar mass bins and different environments.(ii) With the analysis of morphological and structural parameters(e.g., concentration(C) and the stellar mass surface density within the central 1 kpc(Σ1)), red galaxies show more luminous and compact cores than both green valley and blue galaxies, while blue galaxies show the opposite behavior in all stellar mass bins.(iii) A strong negative(positive) relationship between bulge-to-total light ratio(B/T) and specific star formation rate(sSFR)(D_(4000)) is found from blue to red galaxies. Our results indicate that the growth in bulge plays an important role when the galaxies change from the blue cloud, to the green valley and to the red sequence. 相似文献