Patterns in the Turkish reinsurance claim data, 1998–2002: An application of the extreme value theory     

B. Burçak Başbuğ  Henry P. Wynn 《Natural Hazards》2006,39(2):329-342

The devastating 1999 Marmara and Düzce earthquakes led to a significant increase in the earthquake studies in Turkey in geological, engineering and financial aspects. Extreme Value Theory (EVT) has a range of applications from stock market changes to natural disasters like floods and hurricanes. Here EVT is fitted to the ordinary and earthquake reinsurance claims of Turkey.  相似文献   

对天然地基承载力计算公式的理解和应用   总被引：1，自引：0，他引：1  

毛群芳  徐四一 《上海国土资源》2003,(3):26-29

文章就新老国标和上海标准对地基承载力的计算公式进行了分析比较,并认为在上海地区岩土工程勘察报告中提供天然地基承载力设计值fd更适合。  相似文献   

1990—2018年长沙市土地利用变化对生态系统服务价值的影响     

彭毅  王远超  高阳 《中国地质调查》2021,8(3):72-80

评估生态系统服务价值(Ecosystem Service Values,ESV)有利于衡量生态系统服务供给潜力和生态效益的大小,对城市生态规划与土地利用管控起到重要的支撑作用。选择长沙市为研究区域,基于1990、2000、2010和2018年4期土地利用现状遥感监测数据集,利用ArcGIS软件和经本地化校正的当量因子法,分析1990—2018年间的土地利用变化特征,并探讨土地利用变化对ESV的影响。结果表明: ①1990—2018年长沙市土地利用变化轨迹以耕地→林地互相转化以及建设用地对耕地、林地的侵占为主; ②1990—2018年长沙市的ESV共减少53.17×10⁸ 元,降幅3.59%,除水域外各类ESV均呈下降趋势,林地和耕地服务价值减少最明显; ③在各单项服务功能中,水文调节的价值最大,其次是气候调节,两者之和占总价值的54%; ④“退耕还林”“退田还湖”“兴工强市”等政策引起的土地利用变化势必对ESV造成影响,城市快速扩张、土地开发会导致ESV不断下降。综合分析认为,在调整研究区土地利用结构、优化土地配置时应充分重视水域、林地等生态系统服务价值较高的土地利用类型,减缓ESV的下降趋势。  相似文献   

A model for estimating the value of sampling programs and the optimal number of samples for contaminated soil   总被引：1，自引：0，他引：1  

Pär-Erik Back 《Environmental Geology》2007,52(3):573-585

A model is presented for estimating the value of information of sampling programs for contaminated soil. The purpose is to calculate the optimal number of samples when the objective is to estimate the mean concentration. A Bayesian risk–cost–benefit decision analysis framework is applied and the approach is design-based. The model explicitly includes sample uncertainty at a complexity level that can be applied to practical contaminated land problems with limited amount of data. Prior information about the contamination level is modelled by probability density functions. The value of information is expressed in monetary terms. The most cost-effective sampling program is the one with the highest expected net value. The model was applied to a contaminated scrap yard in Göteborg, Sweden, contaminated by metals. The optimal number of samples was determined to be in the range of 16–18 for a remediation unit of 100 m². Sensitivity analysis indicates that the perspective of the decision-maker is important, and that the cost of failure and the future land use are the most important factors to consider. The model can also be applied for other sampling problems, for example, sampling and testing of wastes to meet landfill waste acceptance procedures.  相似文献   

艾比湖湿地调节气候生态服务价值评价     

王继国 《湿地科学与管理》2007,3(2):38-41

增湿调温的气候调节功能是湿地重要的生态功能。位于干旱区的湿地,其增湿调温功能尤为明显。湿地自由水面巨大的水汽蒸发及湿地茂密植被剧烈的水汽蒸腾,是其增湿调温、调节气候的主要物质基础。通过计算艾比湖湿地年水汽蒸发、蒸腾量,得出其每年调节气候的生态服务价值为97788.86×104元,占艾比湖湿地总生态服务价值的31.9%,位居研究区各项生态价值之首。结果表明,增湿调温的气候调节功能是处于极端干旱地理条件下的艾比湖湿地最重要的生态服务功能。  相似文献   

中国大陆部分大震前Hurst指数异常变化特征     

赵翠萍  王海涛 《内陆地震》2001,15(4):331-337

对中国大陆1970年以来12组7级以上地震进行了前后10年左右地震时间间隔序列的R／S分析，滑动计算其Hurst指数H值。H值的时间进程显示，9组大震前2年左右H值在较为稳定的背景上开始出现异常变化，其异常特征为“下降－低值－回升”，地震大多发生在H值回升的过程中，具有中、短期前兆意义。H值的异常过程揭示了在大震孕震系统内地震活动从无序向有序的时间演化过程。  相似文献   

Water resources optimization and eco-environmental protection in Qaidam Basin     

FANG Chuang-lin  BAO Chao 《地理学报》2001,11(2):231-238

In order to realize sustainable development of the arid area of Northwest China, rational water resources exploitation and optimization are primary prerequisites. Based on the essential principle of sustainable development, this paper puts forward a general idea on water resources optimization and eco-environmental protection in Qaidam Basin, and identifies the competitive multiple targets of water resources optimization. By some qualitative methods such as Input-output Model & AHP Model and some quantitative methods such as System Dynamics Model & Produce Function Model, some standard plans of water resources optimization come into being. According to the Multiple Targets Decision by the Closest Value Model, the best plan of water resources optimization, eco-environmental protection and sustainable development in Qaidam Basin is finally decided.  相似文献   

Water resources optimization and eco-environmental protection in Qaidam Basin     

Fang Chuang-lin  Bao Chao 《地理学报(英文版)》2001,11(2):231-238

During the development of Qaidam Basin, which is an arid area in Northwest China, rational water resources utilization and optimization are primal prerequisites, and the main restrictive factors include the following facts: scarcy water resources are non-substitutional and uneven distributed in time and space. Based on the essential principle of sustainable development, this paper adopts Multiple Targets Decision by the Closest Value Model, and succeeds in getting the best plan, which can o…  相似文献   

广义极值分布及其在水文中的应用   总被引：15，自引：3，他引：12  

金光炎 《水文》1998,(2):9-15

广义极值分布,包括Ｉ型、Ⅱ型和Ⅲ型,是一套完整的统计分布。以往,由于研究不足,常常只能采用极值Ｉ型分布,使应用受到了限制。本文中,详细地探讨了广义极值分布的统计特性,首次研制了该分布的离均系数表,并给出了水文频率计算中的示例。分析表明,应用广义极值分布,也能得到较好的适线结果。特别是有了离均系数表,对水文频率分析和各类统计计算是十分方便的。  相似文献   

试论工程场地砂土液化的综合评判——以福-泉高速公路长乐营前三汊港特大桥为例     

黄莉菁  王善雄 《福建地震》1998,(2)

本文以对营前特大桥桥位区的砂土液化的综合评判为例子,提出砂土液化必须运用定值准则的概念与方法并结合各种宏观液化势判定手段进行综合评判,文中还针对水下孔的水位取值进行了讨论。  相似文献