生态旅游对农户家庭收入影响研究——基于倾向得分匹配法的实证分析

参与生态旅游经营已成为保护区周边社区家庭重要的生计,生态旅游经营收入是社区家庭重要的收入来源。本文基于中国7省40个保护区周边社区农户调查数据,研究了家庭参与生态旅游经营对人均纯收入以及人均非农收入的影响,以期能为生态旅游经营的家庭收入效应提供新证据,为缓解保护与发展的矛盾、健全生物多样性保护制度、完善生态旅游发展政策提供实证支撑。研究结果表明:1倾向得分匹配法消除了家庭选择性偏差后,估计出参与生态旅游经营对家庭人均纯收入的收入效应为20%左右,而对人均非农收入的收入效应为47%左右。使用多元线性回归高估了生态旅游经营对家庭人均纯收入的影响,大致高估了8%左右,使用Heckman模型也高估了生态旅游对家庭人均非农收入的影响,大致高估了17%左右。2户主性别、受教育程度、是否为村干部、身体状况、家庭负担比以及耕地面积对农户家庭参与生态旅游经营行为产生显著影响。3结合当前的生态扶贫政策背景,政府以及社会可能高估了生态旅游经营对周边社区家庭收入的影响,追求立竿见影的扶贫效果往往在短期内会获得一定的收效,但是缺乏长期驱动力,最终导致治标不治本的扶贫。因此,政府要合理规划地方生态旅游产业发展,创建一个更有利于社区参与的生态旅游开发模式。一方面,让周边社区家庭参与到生态旅游经营的管理和决策工作中,在生态旅游管理中拥有自主权和决定权;另一方面,建立生态旅游参与的外部约束机制,保障周边社区的利益。     

基于改进混合遗传-支持向量机的CMF产水预测研究

将模拟退火思想和加速遗传特性相结合,改进选择策略和遗传算子,建立加速遗传模拟退火算法（AGSA）;基于支持向量机（SVM）的非线性回归和改进混合遗传算法的因子筛选,构造了支持向量机模型参数的自适应优化算法,提出连续微滤系统（CMF）产水预测模型;通过实测中试规模连续微滤系统产水量变化对模型进行验证,结果表明：该模型较好...     

城市大气环境质量评价模糊识别理论模型

本文提出一种新的大气环境质量评价理论模型——模糊识别模型。提出了大气质量评价的指标综合权重矩阵概念及其确定方法。      

建筑物火灾危险性的模糊评价

依据建筑物火灾危险性的影响因素,应用模糊识别理论及系统安全方法,建立了建筑物火灾危险性的评价指标体系,并应用集值统计方法对各项指标权重进行了处理,将该理论应用到某购物商场火灾危险性评价中,验证了评价模型的准确性,为建筑物防火设计以及安全管理提供了可行的依据。     

Bicyclist injury severity in traffic crashes: A spatial approach for geo-referenced crash data to uncover non-stationary correlates

Introduction: Bicyclists are among vulnerable road users with their safety a key concern. This study generates new knowledge about their safety by applying a spatial modeling approach to uncover non-stationary correlates of bicyclist injury severity in traffic crashes. Method: The approach is Geographically Weighted Ordinal Logistic Regression (GWOLR), extended from the regular Ordered Logistic Regression (OLR) by incorporating the spatial perspective of traffic crashes. The GWOLR modeling approach allows the relationships between injury severity and its contributing factors to vary across the spatial domain, to account for the spatial heterogeneity. This approach makes use of geo-referenced data. This study explored more than 7,000 geo-referenced bicycle--motor-vehicle crashes in North Carolina. Results: This study performed a series of non-stationarity tests to identify local relationships that vary substantially across the spatial domain. These local relationships are related to the bicyclist (bicyclist age, bicyclist behavior, bicyclist intoxication, bicycle direction, bicycle position), motorist (driver age, driver intoxication, driver behavior, vehicle speed, vehicle type) and traffic (traffic volume). Conclusions: Results from the regular OLR are in general consistent with previous findings. For example, an increased bicyclist injury severity is associated with older bicyclists, bicyclist being intoxicated, and higher motor-vehicle speeds. Results from the GWOLR show local (rather than global) relationships between contributing factors and bicyclist injury severity. Practical Applications: Researchers and practitioners may use GWOLR to prioritize cycling safety countermeasures for specific regions. For example, GWOLR modeling estimates in the study highlighted the west part (from Charlotte to Asheville) of North Carolina for increased bicyclist injury severity due to the intoxication of road users including both bicyclists and drivers. Therefore, if a countermeasure is concerned with the road user intoxication, there may be a priority for the region from Charlotte to Asheville (relative to other areas in North Carolina).     

Safety assessment of natural gas storage tank using similarity aggregation method based fuzzy fault tree analysis (SAM-FFTA) approach

Fault tree analysis (FTA) is an important method to analyze the failure causes of engineering systems and evaluate their safety and reliability. In practical application, the probabilities of bottom events in FTA are usually estimated according to the opinions of experts or engineers because it is difficult to obtain sufficient probability data of bottom events in fault tree. However, in many cases, there are many experts with different opinions or different forms of opinions. How to reasonably aggregate expert opinions is a challenge for the engineering application of fault tree method. In this study, a fuzzy fault tree analysis approach based on similarity aggregation method (SAM-FFTA) has been proposed. This method combines SAM with fuzzy set theory and can handled comprehensively diverse forms of opinions of different experts to obtain the probabilities of bottom events in fault tree. Finally, for verifying the applicability and flexibility of the proposed method, a natural gas spherical storage tank with a volume of 10,000 m³ was analyzed, and the importance of each bottom event was determined. The results show that flame, lightning spark, electrostatic spark, impact spark, mechanical breakdown and deformation/breakage have the most significant influence on the explosion of the natural gas spherical storage tank.     

基于模糊层次分析法和证据推理的铁路应急预案评价研究

为解决铁路应急预案评价中存在的不确定性问题,提出基于证据推理的应急预案评价方法,从完整性、可操作性、针对性、协作性和可持续性5个维度构建应急预案评价指标体系;采用模糊层次分析法对指标权重进行计算,并通过证据推理对专家的评价数据进行证据合成,得到各预案评价等级分布;将各预案评价等级分布与评价效用结合,最终得到各预案评价排序。结果表明:实例分析表明,提出的评价方法对于处理不确定多属性的评价问题具有较强的可行性和适用性。     

基于Soft Fuzzy ARTMAP算法的地铁隧洞光纤光栅传感火灾识别研究*

为解决传统火灾报警系统在应对地铁火灾报警时存在的即时性差、灵敏度及智能化水平低等问题,基于Fuzzy ARTMAP网络,结合Yu范数相似度准则与软竞争学习机制,提出1种软竞争学习Fuzzy ARTMAP算法,弥补传统Fuzzy ARTMAP网络胜者为王规则导致的区域重叠而产生误判的不足;结合地铁光纤光栅传感网络数据,将该算法应用于地铁火灾识别。结果表明:与传统的Fuzzy ARTMAP相比,该算法可快速有效地识别地铁火灾趋势,为地铁火灾识别系统研究提供理论支持。     

基于权重敏感度分布研究太湖有机磷农药单一和复合风险

基于实验室能得到的有限毒性数据的物种敏感度分布法(species sensitivity distribution, SSD)很难充分代表特定区域生态系统的物种分布,需要采用考虑生物区系特征进行赋予权重的物种敏感度分布法(weighted species sensitivity distribution,WSSD)。基于太湖物种组成构建WSSD,使用最大累积率(maximum cumulative ratio, MCR)(含风险商法(hazard quotient, HQ))和概率风险评价法(probabilistic risk assessment, PRA)对太湖地区单一和混合有机磷农药的风险进行研究。结果表明,相对于传统SSD方法,加权SSD方法计算的风险商大,且5%生物受影响的概率更大。单一风险评价中,敌敌畏和乐果5%生物受影响的概率超过40%,需要优先控制;最大累积率表明,敌敌畏是复合风险的主要贡献者,单一风险评价中风险较小的马拉硫磷和对硫磷也对复合风险贡献较大,复合暴露风险评价是必要的,混合物的风险商>1,5%生物受复合暴露影响的概率高达90%,有机磷农药复合生态风险不容忽视。