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841.
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843.
为了对建筑火灾疏散条件安全性进行评估,基于Bayesian网络对疏散条件重要构成要素及评估方法逻辑推理过程进行研究探讨。结果表明:评估网络结构、根节点、中间节点及目标节点之间存在因果关联关系;研究得出根节点先验概率与量化节点条件概率表设定方法;Bayesian网络将风险评估与人工智能分析方法相结合,实现对建筑火灾疏散条件的安全性评估,并可用于识别高风险建筑。 相似文献
844.
针对当前配电设备采用的定期检修方式未将可靠性与经济性综合考虑的问题,提出1种基于风险评估结果确定配电设备状态检修决策的方法。首先,根据配电设备健康状态评估结果计算配电设备实时健康指数,利用指数模型对配电设备的实时故障率进行计算;然后,采用最小路法计算配网中所有设备的平均实时故障率,并结合停电时用户损失严重度、配电设备损失严重度和环境损失严重度确定配电设备故障后果严重度;最后,利用风险偏好型效用函数量化计算配电设备的经济运行风险水平,计算各配电设备的相对风险值,并以相对风险值为指标确定各配电设备的状态检修策略。结合算例对所提的方法进行验证,结果表明该方法合理有效。 相似文献
845.
Abstract: Stream and riparian managers must effectively allocate limited financial and personnel resources to monitor and manage riparian ecosystems. They need to use management strategies and monitoring methods that are compatible with their objectives and the response potential of each stream reach. Our objective is to help others set realistic management objectives by comparing results from different methods used to document riparian recovery across a diversity of stream types. The Bureau of Land Management Elko Field Office, Nevada, used stream survey, riparian proper functioning condition (PFC) assessment, repeat photographic analysis, and stream and ecological classification to study 10 streams within the Marys River watershed of northeast Nevada during all or parts of 20 years. Most riparian areas improved significantly from 1979 to 1992‐1993 and then additionally by 1997‐2000. Improvements were observed in riparian and habitat condition indices, bank cover, and stability, pool quality, bank angle, and depth of undercut bank. Interpretation of repeat photography generally confirmed results from stream survey and should be part of long‐term riparian monitoring. More attributes of Rosgen stream types C and E improved than of types B and F. A and Gc streams did not show significant improvement. Alluvial draws and alluvial valleys improved in more ways than V‐erosional canyons and especially V‐depositional canyons. Stream survey data could not be substituted for riparian PFC assessment. Riparian PFC assessments help interpret other data. 相似文献
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847.
Australian reporting requirements for native vegetation require improved spatial and temporal information on the anthropogenic
effects on vegetation. This includes better linkage of information on vegetation type (e.g., native vegetation association),
extent and change, vegetation condition, or modification. The Vegetation Assets, States and Transitions (VAST) framework is
presented as a means for ordering vegetation by degree of anthropogenic modification as a series of condition states, from
a residual or base-line condition through to total removal. The VAST framework facilitates mapping and accounting for change
and trends in the status and condition of vegetation. The framework makes clear the links between land management and vegetation
condition states, provides a mechanism for describing the consequences of land management practices on vegetation condition,
and contributes to an understanding of resilience. VAST is a simple communication and reporting tool designed to assist in
describing and accounting for anthropogenic modification of vegetation. A benchmark is identified for each vegetation association.
Benchmarks are based on structure, composition, and current regenerative capacity. This article describes the application
of the VAST framework as a consistent national framework to translate and compile existing mapped information on the modification
of native vegetation. We discuss the correspondence between these compiled VAST datasets at national and regional scales and
describe their relevance for natural resource policy and planning. 相似文献
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849.
秦皇岛北部山区泥石流地质灾害隐患威胁着当地居民的生命财产安全,严重阻碍了乡村经济的快速发展。以青龙满族自治县茨榆山乡上窝铺泥石流为例,通过实地调查与数据分析,确定了泥石流成因、类型、活动状况、危害性、危险区范围;获取了泥石流流体重度规律、泥石流流速、泥石流流量、一次性固体冲出物主要力学参数特征;根据泥石流的特点及主要参数,提出监测预警方案及工程治理方案。 相似文献
850.
蒽醌染料及其中间体絮凝菌的特性 总被引:14,自引:1,他引:13
本文研究所分离到的真菌NX1对蒽醌染料KNR及其中间体溴氨酸的作用,并考察营养条件、体系PH等对NX1的生长及絮凝作用的影响,结果表明,NZ1及溴氨酸有很好的絮絮凝效果,对PH的适应范围广,最佳碳、氮源分别为蔗粮主尿素。 相似文献