浅谈几种概率分布之间的相互关系

本文简述了几种常用的概率分布之间的相互关系     

河流水质污染中的反问题（Ⅱ）

继续讨论了一类半线性抛物偏微分方程的反问题，在一定条件下，得到了问题的解的存在性，唯一性，并给出了近似解法。     

线性红利界下带干扰风险模型的破产概率

考虑到保险公司在实际经营中收益所具有的不确定性和分红策略，建立一类具有线性红利界和带随机扰动的双复合Poisson风险模型，利用鞅方法给出模型关于破产概率的一个定理及上界．     

美国油气管道基本失效概率评估方法及启示

为充分利用油气管道历史失效数据,减少失效概率评估过程中的主观性,提出油气管道基本失效概率的概念及评估方法。对美国管道及危险物品安全管理局数据库的油气管道里程数据、事故数据及失效因素数据进行全面分析,采用基于事故统计的方法评估油气管道基本失效概率。结果表明:美国危险液体管道、输气集气管道、配气管道发生一般事故的基本失效概率分别为1.29次/(10^3 km·a)、2.17次/(10^4 km·a)及4.08次/(10^5 km·a),发生较大事故的基本失效概率分别为4.58次/(10^4 km·a)、1.41次/(10^4 km·a)及2.38次/(10^5 km·a),发生重大事故的基本失效概率分别为9.09次/(10^6 km·a)、9.79次/(10^6 km·a)及1.11次/(10^5 km·a)。美国基本失效概率可作为油气管道失效概率评估的基准线,也可作为风险可接受标准的依据,但不能直接应用于中国管道风险评价,需对其进行修正,建立适用于中国管道的失效数据库。     

带常利率和相依结构更新风险模型的破产概率

研究了一类具有常利率及相依结构的Sparre Andersen模型, 模型中假设理赔间隔时间决定下一次理赔额的分布情况. 对一般分布情形, 利用推广后的调节系数方程与递归更新技巧, 得到了此模型的最终破产概率上界的估计. 最后以理赔额和理赔间隔时间都服从指数分布的情况下的实例分析来说明该模型的有效性.     

Predicting Acceptability of Jaguars and Pumas in the Atlantic Forest,Brazil

Jaguars and pumas are threatened species in Brazil’s Atlantic Forest, especially at the borders of protected areas. This article assessed the influence of emotions, attitudes, existence value, and agency credibility on acceptability of big cats among rural residents living adjacent to two protected areas in this forest. Data from self-administrated questionnaires (n = 326) indicated those with positive attitudes toward big cats (β = .28, p < .001), those who valued the existence of big cats (β = .14, p < .05), those who would feel sorrow if big cats disappeared (β = .21, p < .001), and those who considered the managing agency as credible (β = .16, p = .002) were more accepting of big cats. The model provided theoretical and practical insights into large carnivore conservation. For example, given the significance of agency credibility, a positive relationship between park authorities and residents is crucial for big cat conservation.     

Parsimonious Covering Probability Model for Turbogenerator Vibration Faulty Diagnosis

The turbogenerator vibration faults have the character of variety. Many faults often occur synchronously. This paper introduces a diagnosing model based on parsimonious covering theory and probability. A model for turtogenerator's fault diagnosis is proposed. The availability of this method is proved by two fault diagnosis examples of turbogenerator. The results show that the model proposed can be used for multi_fault diagnosis together. It may make up shortage for some of expert systems and neural networks in some aspect. From the practice,this model has higher reliability and practicability.     

A reservoir operational rule for irrigation in Japan

Operation of a reservoir for irrigation is more complicated and difficult than that for domestic water supply in Japan, owing to the fact that a requirement for irrigation takes various value depending upon effective rainfall on farmland, soil condition, and so on. Therefore, the reservoirs should be operated to correspond with demand, inflow, and unknown droughts occurring in the future. However, the reservoirs have been operated under operators' experiences without formal operational rules, because any effective theories or methods have been neither developed nor used in Japan at present.On operation of the reservoirs, there are two targets — promotion of effective release and restriction of release in preparation for droughts — conflicting with each other. It is useful to set up the operation with Required Storage for Drought Curve (RSDC) Method to achieve reasonable operation harmonizing those two targets. RSDC is composed with Target Line (TL) and Restrictive Release Lines (RRLs). TL is a target storage level to guarantee that storage will never empty until the end of the irrigation period under a certain probability. If actual storage remains above TL, effective release will be promoted. RRLs are storage levels pointing out the basis of restricting release. If actual storage falls below TL, release will be restrained in accordance with RRLs in order to get over uncertain droughts occurring in the future.In this paper, the theory of RSDC is described and the effectiveness of Rule Curve (RC) based on RSDC Method is illustrated by simulation on a single reservoir for irrigation.     

露地大白菜低温冻害气象指数保险费率厘定方法研究

【目的】为科学厘定露地大白菜低温冻害保险费率提供方法,为其他气象因子指数保险的保险费率厘定提供参考,为政策性农业保险的可持续发展提供助力。【方法】将1957—2018年每年初、终霜冻日期转化为儒历日,计算平均初、终霜冻日期,将平均初、终霜冻日期设定为低温冻害指数保险中的时间起赔阈值,并利用标准差分级法,对起赔阈值设置的合理性进行检验。精确统计大白菜各生长期投入成本,根据灾损率进行加权计算得出赔付比例。通过计算发生概率、灾损率与赔付比例3个因子综合得出露地大白菜低温冻害保险费率,并对种植区域进行加权计算,得出区域内的露地大白菜低温冻害保险费率。【结果】设计了露地大白菜低温冻害气象指数保险中时间和气温起赔阈值的计算方法,并制定了时间起赔阈值的检验方法。设计了低温冻害保险费率3个决定因子发生概率、灾损率和赔付比例的计算方法。【结论】经过检验,将平均初、终霜冻日期设定为丰宁满族自治县地区露地大白菜低温冻害气象指数保险的时间起赔阈值是合理的。露地大白菜在遭受轻、中、重三级低温冻害时的灾损率分别为0.3、0.7和1.0;发芽期赔付比例最高为45%,秧苗期赔付比例最高为75%,莲座期以后赔付比例最高为100%。各乡镇露地大白菜低温冻害气象指数保险费率为2%～3%,经过加权计算得出丰宁满族自治县地区低温冻害保险费率为2.14%。     

基于1961—2100年SPI和SPEI的云南省干旱特征评估

干旱是一个缓慢发展持续时间长的极端气候事件,而气候变化对干旱的影响尤为显著,评估气候变化对云南省干旱特征的影响尤为重要。使用多时间尺度的标准化降水指数（SPI）和标准降水蒸散指数（SPEI）分析了云南省的干旱状况,运用非超越概率和游程理论分别分析了SPI和SPEI的季节性变化和研究区域内的干旱特征。结果表明：1961—1995年冬季SPEI(1)小于等于-1.0的非超越概率为5.2%,但在2066—2100年增加到18.4%;SPEI(6)小于等于-1.0的非超越概率从4.4%增加到21.4%,SPEI(24)从7.0%增加到25.7%。表明由于气候变化,未来有可能发生严重干旱,且中长期干旱比短期干旱更严重。气候变化在1961—1995年和2066—2100年的冬季和夏季造成严重干旱,且中长期干旱严重程度在整个冬季和夏季尤为明显。将SPI和SPEI的时间序列应用于游程理论,发现1961—1995年SPEI(1)的干旱烈度为28.3,到2066—2100年达到60.9,表明气候变化使未来干旱加剧。本研究结果对云南省干旱预测、评估及其风险管理和应用决策具有指导性和实用性,同时可为未来旱作农业生态管理提供一定的依据。