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121.
为完善国内输油气站场综合风险评价技术,提出一种站场综合风险评价模型。该模型基于模糊集理论,重点对传统的RCM与RBI技术进行改进与完善。将故障(失效)后果划分为伤亡后果、经济损失、环境影响和无形损失;采用模糊推理系统代替原有的算法进行计算设备风险,将动设备与静设备的风险转换为统一标度,得到站场综合风险值;最后采用雷达图显示站内设备的风险分布状况。实例分析表明,所建立的综合风险评价模型能够有效地解决定性风险与定量风险的融合问题,可为输油气站场的风险管理提供决策依据。  相似文献   
122.
船舶碰撞严重威胁着船舶水上航行的安全,船舶碰撞危险度的研究能够为船舶避碰提供有效的预防手段和合理的科学依据。选取航道船舶碰撞危险度作为状态变量,选取船舶会遇方式、风速和能见度作为控制变量,运用序次Probit模型拟合出碰撞危险度状态方程。分别对人为判断和序次Probit模型的碰撞危险度利用插值技术,描绘出控制变量对状态变量的作用效果变化特征图。研究结果表明,拟合状态方程可以良好地表征系统状态的连续变化特征,序次Probit模型能够有效克服人为判断的不确定性。  相似文献   
123.
When animals die in traps in a mark-recapture study, straightforward likelihood inferences are possible in a class of models. The class includes M0, Mt, and Mb as reported by White et al. (Los Alamos National Laboratory, LA-8787-NERP, pp 235, 1982), those that do not involve heterogeneity. We include three Markov chain “persistence” models and show that they provide good fits in a trapping study of deer mice in the Cascade-Siskiyou National Monument of Southern Oregon where trapping mortality was high.
Fred L. RamseyEmail:
  相似文献   
124.
The development of a model for assessing the impact and interactions of stressors in the ecosystem of Lake Koronia, based on fuzzy inference, is presented in this paper. The proposed fuzzy inference model assesses the synergistic interactions among several significant stressors on fish production. These stressors include industrial pollution, pesticide and nutrient usage due to agricultural activities, and water level decrease due to irrigation works. Apart from the experts knowledge, expressed in a set of fuzzy rules, a number of parameters such as pH, conductivity, biochemical and chemical oxygen demand, and nitrate concentration were used as stressor indicators. The proposed model is capable of simulating the effect of a large variety of environmental conditions, and it can be used as a dynamic tool for ecosystem risk assessment since it produces both qualitative and quantitative results, allowing for comparisons of predictions with on-going observational research and ecosystem monitoring. Its operation was successfully verified for a number of different conditions, ranging from low stressor impact to high stressor impact (where, in fact, the fish production was diminished). Moreover, the proposed fuzzy inference model can be used as a tool for the investigation of the behavior of the aquatic ecosystem under a large number of hypothetical environmental risk scenarios.  相似文献   
125.
燃煤电厂袋式除尘专家系统开发研究   总被引:1,自引:0,他引:1  
开发了一种袋式除尘系统故障专家诊断方法,用于诊断整个袋式除尘系统的故障现象,通过现场数据采集、操作人员与专家系统的人机对话对故障现象进行分析、推理,并做出相应的解决方案指导操作人员排查故障.燃煤电厂袋式除尘专家系统以知识库、推理机为核心,实现整个袋式除尘系统的设备故障诊断功能和维修故障指导功能,辅以解释机构,人机界面来指导用户如何准确无误地操作运行本系统和袋式除尘控制系统.系统被划分为4个模块:专家系统简介模块,在线故障诊断模块,离线故障诊断模块和专家指导模块.  相似文献   
126.
对环境影响评价中经常使用的三段论推理存在的大前提和小前提的判断问题,以及类比推理在环境影响评价中的应用特点和存在问题进行了分析,并提出了环境影响评价运用推理时应注意的问题。  相似文献   
127.
128.
Ecology is an inherently complex science coping with correlated variables, nonlinear interactions and multiple scales of pattern and process, making it difficult for experiments to result in clear, strong inference. Natural resource managers, policy makers, and stakeholders rely on science to provide timely and accurate management recommendations. However, the time necessary to untangle the complexities of interactions within ecosystems is often far greater than the time available to make management decisions. One method of coping with this problem is multimodel inference. Multimodel inference assesses uncertainty by calculating likelihoods among multiple competing hypotheses, but multimodel inference results are often equivocal. Despite this, there may be pressure for ecologists to provide management recommendations regardless of the strength of their study's inference. We reviewed papers in the Journal of Wildlife Management (JWM) and the journal Conservation Biology (CB) to quantify the prevalence of multimodel inference approaches, the resulting inference (weak versus strong), and how authors dealt with the uncertainty. Thirty-eight percent and 14%, respectively, of articles in the JWM and CB used multimodel inference approaches. Strong inference was rarely observed, with only 7% of JWM and 20% of CB articles resulting in strong inference. We found the majority of weak inference papers in both journals (59%) gave specific management recommendations. Model selection uncertainty was ignored in most recommendations for management. We suggest that adaptive management is an ideal method to resolve uncertainty when research results in weak inference.  相似文献   
129.
为了有效去除地下水中抗生素等有机污染物,本文首次提出有序介孔氧化锰(O-MnOx)为活性催化剂和过硫酸钠(Na2S2O8)为氧化剂制备活化过硫酸钠缓释剂,并将其用于地下水中四环素的降解修复过程.通过有序O-MnOx与H2O2和Na2S2O8构建的两种类芬顿催化反应体系,明确了O-MnOx对过硫酸钠的活化及其对水中四环素优异的降解性能.以O-MnOx与Na2S2O8为活性组分制备的缓释剂在地下水中可以缓慢释放过硫酸根离子.缓释剂中O-MnOx加入比例增加,其释放性能减弱,而Na2S2O8加入比例减少,过硫酸根释放速率就会加快.O-MnOx可以活化过硫酸根溶...  相似文献   
130.
A fuzzy improved water pollution index was proposed based on fuzzy inference system and water pollution index. This method can not only give a comprehensive water quality rank, but also describe the water quality situation with a quantitative value, which is convenient for the water quality comparison between the same ranks. This proposed method is used to assess water quality of Qu River in Sichuan, China. Data used in the assessment were collected from four monitoring stations from 2006 to 2010. The assessment results show that Qu River water quality presents a downward trend and the overall water quality in 2010 is the worst. The spatial variation indicates that water quality of Nanbashequ section is the pessimal. For the sake of comparison, fuzzy comprehensive evaluation and grey relational method were also employed to assess water quality of Qu River. The comparisons of these three approaches'' assessment results show that the proposed method is reliable.  相似文献   
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