An improved artificial immune system for seeking the Pareto front of land-use allocation problem in large areas     

Kangning Huang  Xia Li  Jiayong Liang  Shenjing He 《International journal of geographical information science》2013,27(5):922-946

  相似文献   

强降水的GP分布拟合   总被引：1，自引：0，他引：1  

邹波 《成都信息工程学院学报》2002,17(2):101-104

根据极值理论中处于重要地位的GP分布模型，讨论了模型中的形状参数、位置参数及尺度参数的算法，并将其用于拟合呈偏斜状态的月和日降水量资料中强降水部分，得到强降水发生的直观年数。  相似文献   

后INDC时期全球1.5℃合作减排方案     

顾高翔  王铮 《地理学报》2017,72(9):1655-1668

《巴黎协议》提出要将全球地表升温努力维持在低于较工业化前提高1.5 ℃的水平下,然而当前各国提交的国家自主贡献（INDCs）甚至无法实现成本最低的2 ℃温控目标,后INDC时期全球减排将面临严峻的形势。本文针对全程和终期两种1.5 ℃温控目标实现标准,基于不同的减排原则设置了三种全球合作减排方案,使用集成评估模型CIECIA对其气候有效性和经济可行性进行评价。研究结果显示：若要实现全程1.5 ℃升温控制目标,则各国必须在INDC目标年后立即实现净零排放;终期1.5 ℃温控目标可以使各国在INDC目标年后有一个到净零排放的缓冲期,但是由此带来的地表温度上升反而有损经济发展;方案3对因产业和地理因素在其他方案下经济受损的俄罗斯和高发展国家实行宽松减排措施,在满足终期1.5 ℃目标前提下实现了所有减排参与国经济利益的帕累托改进,是可行有效的国际减排合作方案;方案3显示中国和美国在减排过程中的经济联系更加紧密,而与俄罗斯和高发展国家存在竞争关系,因此可进一步加强与美国的减排合作,并注意协调与俄罗斯和高发展国家的利益关系。  相似文献   

Models for extremes using the extended three-parameter Burr XII system with application to flood frequency analysis / Modèles d’extrêmes utilisant le système Burr XII étendu à trois paramètres et application à l’analyse fréquentielle des crues     

《水文科学杂志》2013,58(4)

Abstract

Abstract A new theoretically-based distribution in frequency analysis is proposed. The extended three-parameter Burr XII distribution includes the generalized Pareto distribution, which is used to model the exceedences over threshold; log-logistic distribution, which is also advocated in flood frequency analysis; and Weibull distribution, which is a part of the generalized extreme value distribution used to model annual maxima as special cases. The extended Burr distribution is flexible to approximate extreme value distribution. Note that both the generalized Pareto and generalized extreme value distributions are limiting results in modelling the exceedences over threshold and block extremes, respectively. From a modelling perspective, generalization might be necessary in order to obtain a better fit. The extended three-parameter Burr XII distribution is therefore a meaningful candidate distribution in the frequency analysis. Maximum likelihood estimation for this distribution is investigated in the paper. The use of the extended three-parameter Burr XII distribution is demonstrated using data from China.  相似文献   

江淮地区极端降水特征及其变化趋势的研究   总被引：3，自引：1，他引：2  

王静  余锦华  何俊琦 《气候与环境研究》2015,20(1):80-88

利用1961~2011年江淮地区5~9月无缺测的71站逐日降水资料,做基于POT(Peaks-Over-Threshold)的广义Pareto分布(GPD),研究江淮地区极端降水的分布特征及其变化趋势。结果表明:(1)皖赣交界处阈值最大,西北和东南部较小,且江淮大部分地区阈值的线性趋势系数为正,其中湖北东部和江西北部的站点,趋势达0.8 mm(10 a)-1以上,并通过了显著性水平0.01的MK(Mann-Kendall)检验。(2)江淮地区中东部多存在连续性极端降水,因此文中采用基于极值指数的自动分串技术获得近似独立的极值样本。(3)尺度参数大值区位于江淮南部,西北、东南以及淮河以北较小,且线性趋势系数在大部分地区均表现为正值,表明出现降水极大值的概率增加。(4)皖赣鄂交界处是极端降水发生概率大值区,而西北、东南及安徽中部地区较小,且极端降水在大部分地区有增加的趋势,特别是在大别山附近及河南东部,2年和20年重现水平的趋势分别达6 mm(10 a)-1和20 mm(10 a)-1以上。  相似文献   

基于多状态Markov链模式的极端降水模拟试验   总被引：3，自引：2，他引：1  

丁裕国  张金铃  江志红 《气象学报》2009,67(1):20-27

文中建立了基于多状态一阶Markov链的逐日降水量随机模式式结合广义帕雷托分布(GPD)产生夏季逐日极端降水量的模拟资料,结果所显示的各种气候特征表明,绝大多数站点(尤其是中国东部多雨地区)都达到较高的精度.分析表明,该模式对中国东部极端降水特征的模拟能力在某些方面优于两状态一阶Markov链模式.对东部6个代表站模拟试验结果表明,月降水均方差、日降水极大值、月半均降水日数、日降水均方差、日平均降水量等指标与实况比较,均证明该模式对逐日降水量的模拟效果较好,基本模拟出降水量的各种特征.对中同东部78个代表站采用的两种模式模拟结果对比发现,除日平均降水量以外,月半均降水日数、日降水平均极大值都与实际观测结果较为一致,总体上优于两状态模式,说明用该模式在全国范围内模拟逐日降水特征尤其是极端降水特征有较高的町行性.例如,由其中6个代表站模拟资料所拟合的极端降水GPD模式具有较高的拟合优度.无论从门限值或重现期值来看都可发现模拟与实测结果有较好的相似性,且两者门限值的误差越小,重现期极值的差距也越小.证明Markov链模式对极端降水的模拟有广泛的适用性.  相似文献   

Linear combinations of order statistics to estimate the quantiles of generalized pareto and extreme values distributions   总被引：2，自引：0，他引：2  

G. Salvadori 《Stochastic Environmental Research and Risk Assessment (SERRA)》2003,17(1-2):116-140

 Ad hoc techniques for estimating the quantiles of the Generalized Pareto (GP) and the Generalized Extreme Values (GEV) distributions are introduced. The estimators proposed are based on new estimators of the position and the scale parameters recently introduced in the Literature. They provide valuable estimates of the quantiles of interest both when the shape parameter is known and when it is unknown (this latter case being of great relevance in practical applications). In addition, weakly-consistent estimators are introduced, whose calculation does not require the knowledge of any parameter. The procedures are tested on simulated data, and comparisons with other techniques are shown. The research was partially supported by Contract n. ENV4-CT97-0529 within the project “FRAMEWORK” of the European Community – D.G. XII. Grants by “Progetto Giovani Ricercatori” are also acknowledged.  相似文献   

Regionalization of floods in New Brunswick (Canada)     

N. El-Jabi  F. Ashkar  S. Hebabi 《Stochastic Hydrology and Hydraulics》1998,12(1):65-82

This study uses the method of peaks over threshold (P.O.T.) to estimate the flood flow quantiles for a number of hydrometric stations in the province of New Brunswick, Canada. The peak values exceeding the base level (threshold), or `exceedances', are fitted by a generalized Pareto distribution. It is known that under the assumption of Poisson process arrival for flood exceedances, the P.O.T. model leads to a generalized extreme value distribution (GEV) for yearly maximum discharge values. The P.O.T. model can then be applied to calculate the quantiles X <sub>T</sub> corresponding to different return periods T, in years. A regionalization of floods in New Brunswick, which consists of dividing the province into `homogeneous regions', is performed using the method of the `region of influence'. The 100-year flood is subsequently estimated using a regionally estimated value of the shape parameter of the generalized Pareto distribution and a regression of the 100-year flood on the drainage area. The jackknife sampling method is then used to contrast the regional results with the values estimated at site. The variability of these results is presented in box-plot form. Received: June 1, 1997  相似文献   

Regionalization of floods in New Brunswick (Canada)     

N. El-Jabi  F. Ashkar  S. Hebabi 《Stochastic Environmental Research and Risk Assessment (SERRA)》1998,12(1):65-82

This study uses the method of peaks over threshold (P.O.T.) to estimate the flood flow quantiles for a number of hydrometric stations in the province of New Brunswick, Canada. The peak values exceeding the base level (threshold), or `exceedances', are fitted by a generalized Pareto distribution. It is known that under the assumption of Poisson process arrival for flood exceedances, the P.O.T. model leads to a generalized extreme value distribution (GEV) for yearly maximum discharge values. The P.O.T. model can then be applied to calculate the quantiles X <sub>T</sub> corresponding to different return periods T, in years. A regionalization of floods in New Brunswick, which consists of dividing the province into `homogeneous regions', is performed using the method of the `region of influence'. The 100-year flood is subsequently estimated using a regionally estimated value of the shape parameter of the generalized Pareto distribution and a regression of the 100-year flood on the drainage area. The jackknife sampling method is then used to contrast the regional results with the values estimated at site. The variability of these results is presented in box-plot form. Received: June 1, 1997  相似文献   

Use of the truncated shifted Pareto distribution in assessing size distribution of oil and gas fields   总被引：1，自引：0，他引：1  

John C. Houghton 《Mathematical Geology》1988,20(8):907-937

The truncated shifted Pareto (TSP) distribution, a variant of the two-parameter Pareto distribution, in which one parameter is added to shift the distribution right and left and the right-hand side is truncated, is used to model size distributions of oil and gas fields for resource assessment. Assumptions about limits to the left-hand and right-hand side reduce the number of parameters to two. The TSP distribution has advantages over the more customary lognormal distribution because it has a simple analytic expression, allowing exact computation of several statistics of interest, has a J-shape, and has more flexibility in the thickness of the right-hand tail. Oil field sizes from the Minnelusa play in the Powder River Basin, Wyoming and Montana, are used as a case study. Probability plotting procedures allow easy visualization of the fit and help the assessment.This paper was presented at Emerging Concepts, MGUS-87 Conference, Redwood City, California, 13–15 April 1987.  相似文献