贝叶斯网络在CFIT风险评价中的应用

针对事故树分析法(FTA)在风险评价中的局限性,在可控飞行撞地(CFIT)事故树的基础上,建立贝叶斯网络(BN).运用推理运算对贝叶斯网络进行定量分析,通过分析计算数据,寻找主要事故致因,并提出对应的改进措施.再将改进措施引入到贝叶斯网络中,评价相关措施的有效性.结果表明,改进措施后,高度设置错误的后验概率最大,将成为预防CFIT的工作重点.最后指出贝叶斯网络方法是对传统的基于故障树分析的风险评价方法的有益改进.     

橡胶林在间种砂仁与咖啡的模式下土壤微生物生物量

探讨了橡胶与砂仁、橡胶与咖啡间种和纯橡胶林3种栽培模式下的土壤微生物生物量及其与土壤有机碳和土壤微生物呼吸强度的关系。结果表明,在这3种模式下,土壤微生物生物量平均值由高到低的顺序为:橡胶 砂仁林地>纯橡胶林>橡胶 咖啡林地。其Cmic范围是380.8~568.3 mg/kg。橡胶 咖啡林地土壤微生物生物量在旱季高于雨季,而其余两种林地则在雨季较高。橡胶林间种作物后,林地土壤表现出比纯橡胶林地有较高的土壤微生物生物量和较短的土壤微生物的转化周期,年转化代数较多;同时,间种也大大改善了林内生态环境。     

Pathological tree-ring structures in Siberian juniper (juniperus sibirica burgsd.) and their use for reconstructing extreme climatic events

The results of identification and dating of frost, false, and light rings in the wood of living and dead Siberian juniper plants growing at the upper forest boundary in the Polar Urals were used to determine the incidence of these structures over the past 630 years. Based on the data of instrumental observations on daily air temperature, the dates and rates of temperature decrease in the years of pathological tree ring formation were analyzed. The recurrence and intensity of extreme temperature drops during the growing seasons of the past six centuries were reconstructed. The severest frosts occurred in the summer seasons of 1601, 1783, 1857, 1882, and 1968.     

Total gaseous concentrations in mercury in Seoul, Korea: Local sources compared to long-range transport from China and Japan

Total gaseous mercury (TGM) and carbon monoxide (CO) were measured every 5 min and hourly, respectively, in Seoul, Korea, from February 2005 through December 2006. The mean concentrations of TGM and CO were 3.44 ± 2.13 ng m⁻³ and 613 ± 323 ppbv, respectively. TGM and CO concentrations were highest during the winter and lowest during the summer. In total, 154 high TGM concentration events were identified: 86 were classified as long-range transport events and 68 were classified as local events. The TGM and CO concentrations were well correlated during all long-range transport events and were weakly correlated during local events. Five-day backward trajectory analysis for long-range transport events showed four potential source regions: China (79%), Japan (13%), the Yellow Sea (6%), and Russia (2%). Our results suggest that measured ΔTGM/ΔCO can be used to identify long-range transported mercury and to estimate mercury emissions from long-range transport.     

汶川地震对四川及周边省区旅游业的影响

依据本底趋势线理论和1997-2008年统计数据,从更高的时空分辨率上,完成了汶川地震对四川及其周边省区旅游业影响的分析,结果显示:①2008年5-12月地震共使四川入境旅游损失112.1万人,国内旅游损失4 410.7万人,损失率分别为61.4%和22.4%;②四川北部主要旅游景点旅游业损失惨重,各景点游客损失率均达到了67.0%以上,其中,九寨沟、都江堰游客损失量较大,分别为212.2万人和194.7万人;③四川周边省区入境旅游遭受了不同程度的冲击,其中,湖北、甘肃损失量最大,分别为35.1万人和26.9万人;各省区受地震影响时间存在较大差异,地震影响期以甘肃最长,其影响期将超过8个月;④2008年汶川地震对四川及其周边省区旅游业的影响,其游客损失量与客流量基数(本底值)成正比;游客损失率与2008年本底值(基数)成反比;损失量和损失率两者均与汶川地震烈度分布存在一定的正比关系,以汶川为中心大致成同心圆状分布。     

Projecting Spatial Patterns of Flood Hazard: Recent Climate and Future Changes over Yangtze River Basin

Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results ...     

基于FFTA城市燃气输配系统安全评估探讨

采用故障树分析方法对城市燃气输配系统的故障树模型进行定性和定量失效分析。针对系统的事件发生概率不确定情况,将模糊数学引入到故障树分析方法,给出了输配系统的模糊故障树安全评估方法。计算表明,该方法用于输配系统的安全评估是行之有效的。     

可靠性理论在建筑施工安全领域的应用研究

针对建筑施工安全管理体系,从系统可靠性的视角,综合运用可靠性方面的知识,构建了建筑施工安全管理系统混联模型。在此基础上,将可靠性分配理论与故障树分析方法相结合,根据系统安全目标的要求,确定混联系统的第一层次各单元事件的可靠性目标值,对构成各单元的各个下属单元采取最小工作量可靠度分配方法,以此类推,从而建立系统中各单元可靠度再分配量化模型。为便于应用,通过建筑施工过程中常见的脚手架坠落实例,详述系统各单元可靠性分配的计算过程。研究表明,可靠性理论可以成功地应用到建筑施工安全领域;使系统在给定的目标值条件下达到系统的安全性优化,从而实现建筑施工安全保障效能,减小事故损失。     

基于动态信任网络的突发事件模型库系统的研究

根据突发事件应急决策的需求,本文结合模型网络法和基于信任筛选器的模型组合方法,提出了动态信任网络的模型组合方法,实现了根据不同的突发事件和不同环境选择适合的模型进行模型组合。在运用动态信任网络模型组合方法的基础上,本文应用Agent技术提出了一种智能化较高的突发事件模型库,不仅增强了模型库的适应性和模型库的自学习功能,而且还可以对耦合灾害和复杂事件链的应急处置提供良好的模型决策支持功能。     

Seasonal Variations in Isoprene Emission from Tropical Deciduous Tree Species

Isoprene is a dominant constituent of the global biogenic volatile organic compounds budget. It plays an important role in regulating the atmospheric trace gas composition including tropospheric ozone concentrations. In this study, monthly measurements of isoprene emission rates were carried out over a 1-year period (December 2002–November 2003) from four Indian deciduous tree species, namely Ficus relegiosa, Ficus infectoria, Pongamia pinnata, and Morus alba, using branch enclosure method. Significantly high monthly variations in isoprene emission rates were observed in all four-plant species. Also, each plant species exhibited pronounced seasonal variation in isoprene emission. Maximum isoprene emissions were observed during summer and minimum during the winter or spring months.