基于变权重和信息熵的区域水资源安全投影寻踪评价模型

区域水资源安全评价是气候变化下区域水安全管理的一项重要调控措施。为合理确定各评价指标的权重,提出了把权重结构分解为评价指标的单样本权重和样本集权重的新观点,建立了用基于加速遗传算法的模糊层次分析法和最小相对信息熵原理确定单样本权重、用基于加速遗传算法的投影寻踪模型和最大信息熵原理确定样本集权重的新模型--基于变权重和信息熵的投影寻踪评价模型（CWE PP）。将CWE PP模型应用于全国水资源安全背景下的巢湖流域水资源安全评价,结果表明：巢湖流域水资源安全状况整体上介于重度缺水与中度缺水之间,偏向重度缺水,略低于安徽省水资源安全状况。用CWE PP进行区域水资源安全评价,物理概念明确,计算结果合理,方法通用,在资源与环境综合评价中具有一定的推广应用价值。     

Genetic diversity and IUCN Red List status

The International Union for Conservation of Nature (IUCN) Red List is an important and widely used tool for conservation assessment. The IUCN uses information about a species’ range, population size, habitat quality and fragmentation levels, and trends in abundance to assess extinction risk. Genetic diversity is not considered, although it affects extinction risk. Declining populations are more strongly affected by genetic drift and higher rates of inbreeding, which can reduce the efficiency of selection, lead to fitness declines, and hinder species’ capacities to adapt to environmental change. Given the importance of conserving genetic diversity, attempts have been made to find relationships between red-list status and genetic diversity. Yet, there is still no consensus on whether genetic diversity is captured by the current IUCN Red List categories in a way that is informative for conservation. To assess the predictive power of correlations between genetic diversity and IUCN Red List status in vertebrates, we synthesized previous work and reanalyzed data sets based on 3 types of genetic data: mitochondrial DNA, microsatellites, and whole genomes. Consistent with previous work, species with higher extinction risk status tended to have lower genetic diversity for all marker types, but these relationships were weak and varied across taxa. Regardless of marker type, genetic diversity did not accurately identify threatened species for any taxonomic group. Our results indicate that red-list status is not a useful metric for informing species-specific decisions about the protection of genetic diversity and that genetic data cannot be used to identify threat status in the absence of demographic data. Thus, there is a need to develop and assess metrics specifically designed to assess genetic diversity and inform conservation policy, including policies recently adopted by the UN's Convention on Biological Diversity Kunming-Montreal Global Biodiversity Framework.     

基于修正遗传算法的夏玉米作物系数及蒸散发估算

农田蒸散量是作物蒸腾量和土壤蒸发量的总和,准确估算农田蒸散量对制定合理的灌溉计划至关重要,进而对农作物的增产保收具有重要的意义.研究作物系数及蒸散量估算模型已成为一个热点科学问题.淮河流域是中国主要的农业生产基地,而夏玉米是淮河流域最主要的粮食作物之一.为研究夏玉米全生育期蒸散估算模型,反映夏玉米逐日作物系数及蒸散量的...     

智能算法及其在环境预警中的应用

智能算法具有学习非线性问题的能力,可有效优化环境模型结构与参数,是环境预警的重要工具。重点分析了遗传算法和人工神经网络的相关特征,并以太湖蓝藻水华预报预警为例,介绍其在提高环境模型精度中的应用。     

重大危险源大规模人群疏散决策模型研究

为在重大危险源应急救灾中给决策人员提供最优的人群疏散方案,提高抢险救灾能力,将疏散过程分为两个阶段——先将灾民疏散至临时疏散救援点,再根据灾民受伤的严重程度有选择地将其疏散至定点医院进行救治。综合考虑灾害对人群疏散造成的影响,将道路危险系数等参数加入目标函数中,将灾区按灾害程度赋予不同的优先疏散系数并将之反映在时间满意度上,以总疏散时间最小为目标函数,建立疏散模型,并应用遗传算法进行求解。最后,通过MATLAB进行仿真计算。研究结果表明:模型和算法给出的疏散策略是有效的。     

基于元胞遗传算法的多目标应急资源配置

为解决不同灾情下多目标多周期灾后救援问题,减少受灾损失,对灾后应急资源配置进行研究。从物流成本和系统损失2个方面最小化救灾行动的成本和最大化有限救灾资源的分配,建立基于路况的多目标应急资源配置模型,将帕累托前沿和超体积作为元胞遗传算法的求解性能指标,开展元胞遗传算法与遗传算法对模型的求解对比实验。结果表明:元胞遗传算法能较好地求解多目标多周期应急资源配置模型,且求解性能比遗传算法更好;通过对模型的求解,可为决策者基于不同灾情下的应急决策提供参考。     

REAL CODED GENETIC ALGORITHM OPTIMIZATION OF LONG TERM RESERVOIR OPERATION1

ABSTRACT: An optimization and simulation model holds promise as an efficient and robust method for long term reservoir operation, an increasingly important facet of managing water resources. Recently, genetic algorithms have been demonstrated to be highly effective optimization methods. According to previous studies, a real coded genetic algorithm (RGA) has many advantages over a binary coded genetic algorithm. Accordingly, this work applies an RGA to obtain the 10‐day (the traditional period of reservoir operation in Taiwan) operating rule curves for the proposed reservoir system. The RGA is combined with an effective and flexible scheme for coding the reservoir rule curves and applied to an important reservoir in Taiwan, considering a water reservoir development scenario to the year 2021. Each rule curve is evaluated using a complex simulation model to determine a performance index for a given flow series. The process of generating and evaluating decision parameters is repeated until no further improvement in performance is obtained. Many experiments were performed to determine the suitable RGA components, including macro evolutionary (ME) selection and blend‐α crossover. Macro evolution (ME) can be applied to prevent the premature problem of the conventional selection scheme of genetic algorithm. The purpose of adjusting a of a crossover scheme is to determine the exploratory or exploitative degree of various subpopulations. The appropriate rule curve searched by an RGA can minimize the water deficit and maintain the high water level of the reservoir. The results also show that the most promising RGA for this problem consists of these revised operators significantly improves the performance of a system. It is also very efficient for optimizing other highly nonlinear systems.     

水质综合评价的遗传投影寻踪插值模型

为解决各单项水质评价指标评价结果的不相容问题 ,提高水质综合评价各层次的分辩力和评价模型的精度 ,本研究采用大样本数据 ,利用投影寻踪、遗传算法、插值型曲线和水质评价标准 ,为水质综合评价建立了一种新的数学模型———遗传投影寻踪插值模型 (GPPIM)。实例研究表明 ,GPPIM建模方法直观、可靠、精度高 ,既具有较强的分类功能 ,又具有较好的排序功能 ,可广泛应用于各种环境质量的综合评价。     

Atmospheric Change and the Diversity of Aquatic Invertebrates: Are We Missing the Boat?

The response of natural systems to atmospheric change may depend critically on species diversity and on the genetic diversity (variability) found within their respective populations. Yet, most surveys of aquatic invertebrates account for neither. This may be of particular concern for benthic populations in running waters because of the considerable variability and the fragmentary nature of these habitats (e.g. isolated watersheds). In such habitats, species with limited genetic variability and/or limited dispersal capabilities (genetically differentiated populations) may be unable to track rapid environmental change, and may be more susceptible to climatic perturbations. We present a conceptual framework to illustrate some of the potential problems of ignoring population genetics when considering the impacts of global atmospheric change. We then review a simple method to assess population genetic structure and we evaluate available data on the genetic structure of North American stream invertebrates. These data indicate that benthic taxa often consist of genetically differentiated local populations, or even previously unknown species. Accordingly, our limited knowledge of population structure among benthic invertebrates may result in the unwitting loss of genetic and/or species diversity. Enhanced taxonomic research incorporating molecular techniques is clearly warranted. Conservation strategies based on the preservation and remediation of a diversity of aquatic habitats are likely to be our best means of ensuring species and genetic diversity of invertebrate taxa.     

Dechlorination of dichlorodiphenyltrichloroethane (DDT) by Fe/Pd bimetallic nanoparticles: Comparison with nZVI,degradation mechanism,and pathways

Frontiers of Environmental Science &; Engineering - Acclimation is the main method to enhance the productivity of microorganisms in environmental biotechnology, but it remains uncertain how...