首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 93 毫秒
1.
根据数理统计的大数原理,建立概率模型对我国地质灾害的分布特征进行研究.首先分析地质灾害在六个行政区的分布特点,然后分析隶属于各行政区的所有省、市和自治区的地质灾害分布特征.结果显示不同类型与不同的区域之间存在着不同程度的强相依性,分布格局明显.  相似文献   

2.
利用扩展BurrⅫ分布构建了改进的广义帕累托分布模型—MGPD模型(Meliorated Generalized Pareto Distribution),由此得到了地质灾害损失的在险风险值和最大可能损失估计值。以湖南省娄底市地质灾害损失数据实证分析,结果显示:MGPD模型在刻画地质灾害损失数据时,比GPD模型的精度更高,具有更广泛的适用性。  相似文献   

3.
针对我国道路交通安全风险评价问题,从交通事故发生率、交通事故严重程度和交通事故发生趋势三个方面,筛选出反映交通安全综合风险的9项指标.引入灰色关联分析法确定指标权重,运用模糊综合评价法定量计算风险值,并将方法应用于我国其中的31个省市2013年道路交通安全综合风险评价研究.结果表明:我国道路交通安全风险平均值为55.1679.西北地区和东南地区的9个省市属于高风险等级,中风险区域广泛分布于中部、东北和西南地区;低风险区域为吉林省、内蒙古自治区、贵州省和北京市.  相似文献   

4.
经典的判别分析尽管也注重变量的精简,但要求各待判样品一律提供相同个数的变量取值,仅在变量齐全的情况下做一次判断即肯定归属,以至往往有变量个数不少,判断正确率却不高的现象。这自然有多种原因,诸如关于分布模型的假设不甚通用,基于将空间一分为二的判别规则过于绝对化以及总的离差阵埋没了某些子集的特性等等。 Kendall曾提及将空间分为三个区域,落入其中两个区域者作肯定性判断,否则便待判的做法,并就两个母体的判别问题提供了一个建立在秩次基础上的实施办法,分布自  相似文献   

5.
《数理统计与管理》2013,(4):699-705
针对城市流通蔬菜污染问题中涉及到空间因素,本文提出利用空间统计学的模拟方法,通过获取多个不同模拟结果之间的差异来揭示研究区域蔬菜污染的整体空间分布形态。文章以中山市2010年12月6种常见蔬菜(上海青、菜心、生菜、白菜、芥兰、番茄)抽检数据为研究对象,给出每种蔬菜污染的空间分布模拟结果,再以6种蔬菜的污染监测预警级别为标准,得到研究区域中不同蔬菜污染的空间预警分析结果,该结果为政府部门对蔬菜污染的监控管理提供了科学依据。  相似文献   

6.
作者在本文提出通信规模的结构服从一种分形结构——负幂律分布。根据不同区域通信规模所具有的不同分维值,定量描述不同区域间局部通信规模或同一区域在不同时期的通信规模的差异程度  相似文献   

7.
基于GWR模型的河南省人口分布的影响因素研究   总被引:1,自引:0,他引:1  
近年来,人口作为一种基本信息已成为目前研究的热点问题之一.人口分布可能受自然,经济,社会,政治等诸多因素的影响.因此,人口分布的研究对于了解不同类型区域的人口资源与经济发展之间的关系,因地制宜地发展本地经济具有重大意义.课题以河南省统计年鉴数据为基础,研究河南省人口分布的影响因素.具体来说,首先利用Surfer软件的可视化技术研究了河南省人口数量的空间变化特征.其次,利用近年来发展起来的地理加权回归模型对河南省人口分布的影响因素进行了定量分析.通过上述分析提取有效信息,从而为制定合理的人口政策和实现人口的有序流动提供必要的理论支持.  相似文献   

8.
威布尔分布可以作为绝大多数机电产品的失效分布,但实践中难以获得威布尔分布的参数精确数值.采用不同方法所得到的估计结果往往有所差异,不同来源的参数估计结果其形式也往往难以统一.考虑广义标准灰数思想,对多源异构不确定数据进行统一表征,得到参数灰区间,构建灰参量威布尔可靠度函数;然后基于信息补充导致区域收敛的正态分布假设,将灰参量可靠度函数的白化问题转化为封闭区域的面积收敛问题,并构建以封闭区域面积最小和总信息补充成本最低为目标函数的多目标规划模型,得出封闭区域收敛时威布尔分布参数白化为灰参量区间的核的结论.最后采用Matlab对案例求得5组结果,验证了所述方法的有效性.  相似文献   

9.
层次分析与判别排序在东北区薪炭林区划中的应用   总被引:1,自引:0,他引:1  
作为全国薪炭林区划协作研究工作的一部分,在东北区薪炭林区划工作中,我们曾试用层次分析与判别排序作为区划的基本手段取得较好的效果,完成了区划工作, 薪炭林区划即须过分析研究该区各市县薪柴资源地域分布的差异性和能源资源状况,将研究地区分成不同类型的子区域,揭示不同子区域能源资源的优势、潜力及利用现况,明确薪炭林发展方向和途径,为合理按排薪炭林发展规划和指导农村能源建设提供科学依据. 区划采用的基本原则为:1.要把社会发展需求与自然经济条件的合理利用结合起来,确保区划方案现实可行.2.要考虑薪材资源丰富程度及对它的影响…  相似文献   

10.
基于马尔科夫链蒙特卡洛(简记为MCMC)模拟的参数贝叶斯估计,对改进的广义帕累托分布(简记为MGPD)模型进行了优化,并利用该模型得到了地质灾害损失的在险损失值(简记为VaR)和条件损失值(简记为CVaR).以湖南娄底市地质灾害损失数据进行实证分析及模型适应性检验,结果表明:优化后的模型不仅具有很好的极值数据描述能力,而且具有较强的适用性.  相似文献   

11.
A new class of bivariate survival distributions is constructed from a given family of survival distributions. The properties of these distributions are analyzed. It is shown that the same bivariate survival function can be derived using two radically different concepts: one involves transformation of the well-known bivariate survival function; the other involves correlated stochastic hazards. The new conditions that guarantee negative associations of life spans are derived. An exponential representation of the survival function for two related individuals is derived in terms of the conditional distribution of the stochastic hazards among survivors. Versions of the multivariate correlated gamma-frailty model are investigated.  相似文献   

12.
A procedure for locating depots and their distribution areas is described and illustrated for the area of South-east England. The solution was obtained by an iterative search procedure. The program was written in a flexible fashion so as to be able to deal with multi-factory deliveries and a variable number of depots. Existing depots were allowed for in the procedure. Arrangements were made to avoid impermissible depot locations and to allow increased driving time for natural hazards.  相似文献   

13.
Multivariate failure time data often arise in biomedical studies due to natural or artificial clustering. With appropriate adjustment for the underlying correlation, the marginal additive hazards model characterizes the hazard difference via a linear link function between the hazard and covariates. We propose a class of graphical and numerical methods to assess the overall fitting adequacy of the marginal additive hazards model. The test statistics are based on the supremum of the stochastic processes derived from the cumulative sum of the martingale-based residuals over time and/or covariates. The distribution of the stochastic process can be approximated through a simulation technique. The proposed tests examine how unusual the observed stochastic process is, compared to a large number of realizations from the approximated process. This class of tests is very general and suitable for various purposes of model fitting evaluation. Simulation studies are conducted to examine the finite sample performance, and the model-checking methods are illustrated with data from an otitis media study.  相似文献   

14.
The analysis presented is concerned with the equivalence among biological bodies of different shapes and dimensons in quasi-static field conditions by means of appropriate ellipsoidal models. The results are useful in order to assess the applicability of the power frequency high voltage exposure hazards on animals to man.  相似文献   

15.
Behavioural reactions to potential hazards are likely to bedetermined by psychologically derived factors (risk perceptions)as well as rational estimates of risk .Research has shown thatrisk perception is a complex psychological construct, wheredifferent potential hazards are associated with different hazardcharacteristics. One of the most important determinants of risk perception isknowledge about a given hazard. It is probable that reactionswill be determined not only by what is conveyed in the contentof risk information but also by other characteristics of theinformation source. A predominant source of risk informationfor the public is the media, although there are at present noadequate models available to describe how such risk informationis conveyed. If communication with the public on issues of riskis to be effective, then it must take due account of the roleand effect of the media. Given that the public is suddenly exposedto a problem by the media in the context of a 'crisis', it ispossible that polarization of views among the public and scientificcommunity (and other interested parties, such as pressure groups)will take place, often on the basis of inadequate data. This research examines how the British press communicate riskinformation. The focus is food-related hazards: food biotechnology,microbiological hazards, food irradiation, chemicals and pesticideresidues, and food additives. The development of a content-analysisschedule, and its subsequent application to 182 newspaper reportsrefemng to food-related hazards, is presented. Correspondenceanalysis of the resulting data indicated that substantial differencesin risk reporting occurs for hazards with different perceptualcharacteristics. Methods of testing derived models of mediatransmission of risk information against formation of attitudesare discussed.  相似文献   

16.
In many cases, the interdependencies among the hazards in a system can be expressed by means of a hazard network, in which the nodes correspond to the hazards and the links indicate how they depend on one another. We formulate a set of mathematical optimization models which apply in such circumstances and can be used to determine the best protection or prevention strategy based on the estimated costs of mitigation. We illustrate how the model works in three different situations: (1) when total mitigation of any hazard eliminates all the hazards that follow it, (2) when a number of hazards must be totally mitigated to achieve the same effect, and (3) when partial mitigation helps to reduce the risks associated with subsequent hazards. The models developed and illustrated are readily scalable and should apply to a wide range of risk management problems.  相似文献   

17.
郭春娜 《运筹与管理》2020,29(2):205-211
本文构建了技术进步内生的生产函数,并根据企业微观面板数据,采用OP模型和收敛模型测算了中国制造业全国层面及区域层面的全要素生产率,并分析了制造业全要素生产率的地区差异和收敛性。结果显示:2002~2011年中国制造业全国层面全要素生产率年均增长2.36%,受金融危机的影响,2008~2011年仅为-2.14%;在地区差异上,东部地区制造业全要素生产率要低于中西部地区;收敛分析显示,全域的全要素生产率既不存在β收敛也不存在σ收敛,但却存在“俱乐部”收敛,即中西部地区和东部地区内部各自收敛;同时,本文的分析还显示,资本增长率和研发投入都对全要素生产率的增长有显著正影响。  相似文献   

18.
分块矩阵的Cassini型谱包含域   总被引:3,自引:0,他引:3  
逄明贤 《数学学报》2000,43(3):535-544
本文讨论了复分块矩阵的谱包含域问题,得到了两类新的谱包含域及谱分布 定理,所得结果推广与改进了[1-9]的结果.  相似文献   

19.
Inelastic materials that form dislocation cells on being deformed are modeled as a constrained-mixture of plastically hard and soft regions by associating different natural states with these regions. The deformation gradient from the reference configuration to the natural configuration is identified as the plastic deformation tensor and the stress is measured from a changing set of natural configurations. Two sets of natural configurations are introduced: one for the hard phase and the other for the soft phase. The full elastic response of the body is determined by elastic responses from different natural configurations. The energy stored in the dislocation networks is explicitly accounted for in the Helmholtz potential. Within a specialized constitutive set up, the soft phase is assumed to be non-hardening while the hardening response of the hard phase is dependent upon the response of both the hard and soft phases. These special forms are used to model the response of the material that forms cellular structures when subjected to cyclic loading.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号