The analysis of red giant branch photometry in galaxies     

C. M. Frayn  G. F. Gilmore 《Monthly notices of the Royal Astronomical Society》2002,337(2):445-458

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A new method for the derivation of the closed nets in the phase diagram space of multisystems. I. The absent phase substitution method     

J. Hu  H. Yin  Z. Duan 《Journal of Metamorphic Geology》2004,22(5):413-425

A new convenient combinatorial method is developed here to derive the invariant points in multisystem closed nets – the absent phase substitution (APS) method. It substantially simplifies the derivation of the closed nets in multisystems with many components and phases. For the multisystems whose total phase number (N_PS) ≤ twice the number of the absent phases (m) in an invariant assemblage, the method can yield regular closed nets with or without globally absent phases; for other multisystems, the method can yield the regular closed nets with globally absent phases. As examples, the APS method was used to predict: (1) the regular closed nets of unary to quinary n + 4‐phase multisystems, unary 6‐phase multisystem and ternary 8‐phase multisystem; (2) the basic properties of the regular closed nets of the quaternary and quinary multisystems with n + 4 and n + 5 phases. Two multisystems were chosen to demonstrate how to select a realistic closed net from the numerous possible closed nets of a complex multisystem, and how to derive a realistic partially closed‐net, closed‐net‐diagram and the related realistic straight‐line‐net‐diagram. Comparisons of our APS method for the derivation of complicated closed nets with other methods indicate that this method is much simpler and more efficient.  相似文献   

一种用于界定经济客体空间影响范围的方法——Voronoi图   总被引：39，自引：4，他引：35  

王新生  郭庆胜  姜友华 《地理研究》2000,19(3):311-315

经济客体的空间影响范围界定十分复杂,但在区域规划和城市规划中有着重要的理论和实际意义。该文提出可采用Voronoi图方法用于经济客体的空间影响范围界定,介绍了Voronoi图的基本原理和其若干扩展,编写了生成Voronoi图的程序,最后以城市为例探讨了Voronoi图在经济客体空间影响范围界定中的应用。  相似文献   

福建沿海设计潮位查算图研制   总被引：4，自引：1，他引：3  

李松仕  林永泉  胡美英 《水文》2000,20(1):26-30

就目前在推求设计位中若干争议的问题进行了分析,应用统计假设检验理论研究了年最高潮位的随机性,提出了通过区分不同的组合概率法推求设计潮位的新方法,根据福建沿海位资料研制了设计潮位查算图,以便于无潮位观测资料的地区查求出设计潮位。  相似文献   

基于计算机图形学的土壤质地自动分类系统   总被引：1，自引：0，他引：1  

张丽萍  张镱锂  王英安 《地理科学进展》2006,25(3):86-95

国内外通行的国际制、美国农部制等土壤质地分类制, 均采用传统的人工查找平面正三角 坐标图方法获取质地名称, 这对大批量土样费时费力、精度难以控制。结合国外土壤质地计算机 分类方法研究的状况, 本文基于计算机图形学技术, 利用Visual Basic 平台, 设计并完成了更具实 用性、更便于国内使用的土壤质地自动分类系统( STAC) 。STAC 系统的特点是简单、方便、快速、 直观, 具有单个或批量土壤质地的自动分类、图形显示、统计、分析以及支持用户自定义分类制等 多种功能。文中着重阐述了其中的计算机图形学实现原理和关键技术。  相似文献   

岩土工程数值计算中的无网格方法及其全自动布点技术   总被引：14，自引：3，他引：11  

蔡永昌  朱合华 《岩土力学》2003,24(1):21-24

自然单元法采用无网格的思想全域构造插值函数,它的求解精度高,计算时间少,可准确地施加边界条件,兼具有无网格法和有限单元法的优点和特点,是一种理想的用于岩土及地下工程分析计算的数值方法。文中简要地介绍了自然单元法的基本理论,并针对岩土及地下工程问题特点,给出了一种无网格离散点的全自动布置方法。  相似文献   

Key factors which influence the success of community forestry in developing countries     

《Global Environmental Change》2015

While community forestry has shown promise to reduce rural poverty, improve reforestation and potentially offset carbon emissions, many projects have failed, either partly or completely. In order to understand why community forestry succeeds or fails, we examined in detail the literature related to community forestry from three countries, Mexico, Nepal and the Philippines. We also drew on experiences in other countries in Asia, Latin America and Africa. We identified five main interconnected factors which the literature suggests are often critical to the success of community forestry. To integrate the many ways in which community forestry projects can improve the state of these factors, we use the concept of ‘bonding social capital’, i.e. communities’ ability to work together towards a common aim and ‘bridging social capital’, i.e. their ability to liaise with the outside world. To understand the interaction of the five success factors and the way in which improvements to bonding or bridging social capital may affect them, we developed a causal diagram which depicts the interrelationships between the success factors and the key points at which project inputs may be best applied. It is clear from our analysis that failing to appreciate both the complexity and interaction of the various influences may lead to project failure.  相似文献   

The astrophysical parameters of Majaess-95 and Majaess-225     

A. L. Tadross 《Astronomische Nachrichten》2023,344(10):e20230073

Most astrophysical parameters of the two stellar clusters Majaess 95 and Majaess 225 have been investigated here for the first time using the third data release of the Gaia space mission (Gaia-DR3). The membership probabilities of stars were assigned using the pyUPMASK algorithm. The parallaxes offset has been corrected using the zero-point correction code of Lindegren et al. (Lindegren et al. 2021, A&A, 649, A4). Using the clusters' members with membership probabilities >0.50, we calculated the distance to the clusters of 3311 and 3020 (±130) pc, respectively, which agree with the results from our isochrone fitting on the color-magnitude diagram. The ages are found to be 282 (±20) and 12.6 (±2) Ma. Also, the reddening, heliocentric distances, luminosity function, mass function, and total mass were estimated. On studying the dynamic state (relaxation time), we found that Majaess-95 is a relaxed cluster, while Majaess-225 is not relaxed yet.  相似文献   

ECMWF、日本高分辨率模式降水预报能力的对比分析   总被引：9，自引：2，他引：7  

张宏芳  潘留杰  杨新 《气象》2014,40(4):424-432

利用2012年4月1日至2013年3月31日ECMWF、日本高分辨率模式降水预报资料,全国2419个台站逐6 h降水量观测、CMORPH(NOAA Climate Prediction Center Morphing Method)卫星与全国3万余个自动站逐小时降水融合资料,基于列联表预报评分、泰勒图等统计方法,客观对比分析ECMWF、日本高分辨率模式对中国逐6、12和24 h分段降水的预报能力,主要结论如下:(1)整体来说,ECMWF对降水的预报优于日本模式,日本模式预报离散度偏大,而ECMWF预报相对平稳,与观测更加一致;(2)两个模式晴雨预报中降水发生频率较实际偏高,暴雨预报频率较实际偏低,随着分段间隔的增加,这一情况有所改善;(3)ECMWF模式6 h分段降水晴雨预报评分低于日本模式,暴雨预报评分整体高于日本模式,12和24 h分段ECMWF模式晴雨、暴雨预报评分一致高于日本模式;(4)通过调整阈值改变预报偏差能够在一定程度上提高预报技巧;(5)就空间分布来看,模式在东南地区Bias、CSI技巧评分整体优于西北地区。  相似文献   

利用层次Voronoi图进行点群综合     

李佳田  康顺  罗富丽 《测绘学报》2014,43(12):1300-1306

通过距离权重描述点的重要程度,采用改进的k-means算法得到点群的聚类中心,进而以聚类中心为基础,构建了层次加权Voronoi图与Voronoi层次树结构.以点群的分布范围、排列方式与密度为度量,给出了基于Voronoi层次树结构的点群综合方法,确保了点群综合前后在空间形态分布上的一致性.结合地理统计学计算,对综合方法作了进一步的量化评估与优化.经验证,本文方法是可行、有效的.  相似文献