京津冀地区生命线系统宏观脆弱性动态仿真模拟

为了研究京津冀地区生命线系统宏观脆弱性的动态变化情况,利用2005-2014年的统计年鉴基础数据,从敏感性和应对-恢复能力两个方面构建了京津冀地区生命线系统宏观脆弱性空间差异的指标体系;采用MIE模型对研究区域的生命线系统脆弱性风险进行了风险评价,京津冀地区高和较高风险区达到50%,中等以上更达到92%;结合主成分分析法对京津冀地区生命线系统脆弱性的时空特征进行了分析.脆弱性空间差异在形式、幅度和主要驱动因素上各有不同,且京、津、唐等大中城市脆弱性较大.时间特征中,北京变化浮动最大,天津、唐山及廊坊的脆弱性始终高于区域平均水平,石家庄、张家口、承德、秦皇岛及邢台脆弱性呈下降趋势,其余城市脆弱性在区域平均水平左右浮动.     

基于可拓方法我国银行体系脆弱性的评价

在银行体系脆弱性评价中借助物元的概念,建立了银行体系脆弱性评价模型,并采用较为客观的评价方法——可拓方法对该模型进行评价,介绍了一种新的银行体系脆弱性评价方法.消除了其它主观评价方法带来的偏差,从而为我国银行体系脆弱性的监管决策提供有益参考.     

地下水脆弱性风险预警和评估的区间三角模糊多属性决策模型

应用基于逼近理想解排序法的区间三角模糊多属性决策模型,对三江平原六大分区地下水脆弱性进行了风险预警和评估.评估结果与前人吻合,可为有关决策部门采取相应降低环境风险的措施提供参考.实例验证表明,模型具有更高的计算精度和更好的评价效果,为有关环境风险决策部门对地下水风险预警和评估提供了新的思路和方法.     

地下水与社会经济的协调发展分析模型及其应用

在我国北方水资源短缺的许多地区,发展用水主要是靠加大地下水超采量来维持的,即通过牺牲后备资源和生态环境,地下水资源对国民经济发展做出了重要贡献.但随着地下水资源的枯竭,可能对区域社会经济带来一定影响.为评价这种影响,提出了一个协调发展模型,简单实用,能够反映客观实际.并在海河流域的典型区域进行了实际应用,结果表明许多地区的地下水环境状况相当不容乐观,在发展经济的同时,也应当注意生态环境的保护.     

基于改进BP神经网络的柘林湾水质综合评价模型

建立了基于改进 BP神经网络的柘林湾水质综合评价模型 .实验结果表明 ,新模型的网络训练收敛速度比未改进的模型快、误差更小 ,而且能克服 BP网络所存在的“过拟合”现象 .因此 ,它的泛化能力强 ,结果客观、合理 .     

基于改进TOPSIS法的海南省资源环境承载力时空差异研究

资源环境承载力评价可以为区域资源环境管理提供有效的决策依据.以海南省作为研究对象,通过构建资源环境承载力指标体系,结合熵权法来改进TOPSIS法,构建资源环境承载力评价模型,从时间序列和空间分布对海南省资源环境承载力进行分析.结果表明:1)在时间序列上,2010-2019年海南省资源环境承载力总体处于上升趋势,并且承载能力仍有较大的提升空间;2)在空间分布上,2019年海南省资源环境承载力以低承载为主,占全省面积的67.35%;高承载面积仅占总面积的6.63%.进一步说明除海口市外的海南省其他区域资源环境条件较弱,因此,在注重高质量发展的同时,更应做到区域协同发展,从而推动整体区域资源环境承载力水平的提高.     

突发事件影响度的仿真研究

以突变理论为基础,给出了突发事件影响度的仿真评价方法.通过采用三角分布描述专家对子指标影响程度的估计,建立了突发事件影响度的仿真模型.通过对仿真模型进行独立重复仿真实验,获得突发事件影响度的评价值并进行统计分析.为克服评价结果偏高而区分度不高的缺陷,研究了评价值的转换方法,转换后的评价值能更好地体现人们对突发事件的认知程度.该方法可将定量、定性指标纳入同一模型中,并可避免人为确定权重的主观性.算例表明,在基于突变理论的评价模型中结合系统仿真的思想,是研究突发事件影响度的有效方法.该方法具有良好的可靠性,也可适用于其它综合评价问题.     

基于改进灰色斜率关联度的评价研究

提出了一种对灰色斜率关联度的改进模型,并分析了它的性质,改进后的关联度模型能够反映序列的正、负相关关系,具有对称性、唯一性、可比性和无量纲化后的保序性.改进的灰色斜率关联度能够更充分地利用数据所包含的信息,所得关联分析结果较为客观可靠,最后以实例验证了评价方法的有效性与实用性.     

数据的多流形结构分析

建立了基于ALM和权值的LRR聚类改进模型,对高维数据进行分析,将其分为两个独立的子空间,并与传统k-means聚类模型进行对比,采用评价指标模型对聚类结果进行评价分析.提出的LRR聚类改进模型在正则项引入了权重系数w,可以更好地将扰动分开,求解结果及评价指标均有效地验证了其稳定性、精确度等性能均有所提升.建立了SMMC改进模型,对机器工件外部边缘轮廓进行分类.从求解结果可看出该模型非常适合用于处理混合多流形聚类问题,对于比较复杂的曲线有着很好的分类性能.按照数据预处理、数据建模分析、模型结果评价步骤,通过使用谱聚类分析和多流形学习方法,对所给出的高维数据进行分析和处理,并通过评价模型得出相应的评价指标,对数据的多流形结构进行了深入的研究和探讨.     

基于模糊多因素多层次评价模型的缺水度研究

根据黑龙江省水资源特点,从影响水资源短缺的水资源量、暴露性、脆弱性、人口和工程技术五方面入手,考虑14个二级评价指标,应用层次分析法、和模糊多因素多层次评价法建立综合评价模型.结果表明黑龙江省水资源处于一般风险等级,属于中度缺水.     

Evaluación probabilista de la capacidad,fragilidad y daño sísmico de edificios de hormigón armado

Currently, many structures existing in seismic areas are highly vulnerable because they have been built without the use of seismic design codes or by using outdated codes. Often, methods for assessing the vulnerability of the structures do not take into account that their seismic behavior is dynamic and highly nonlinear and, moreover, that the structural characteristics and action have large uncertainties. This article aims to assess the vulnerability of structures taking into account that the mechanical properties of materials and the seismic action are random variables, by using advanced techniques based on the Monte Carlo method and on the nonlinear stochastic dynamics. The results obtained with these techniques are compared with those corresponding to a standard vulnerability assessment, based on deterministic models, in order to highlight the differences between both approaches. The main conclusion of this work is the need to address the vulnerability assessment problem from a probabilistic perspective which, combined with advanced nonlinear static and dynamic structural analysis techniques, provides a powerful tool giving information impossible to be captured by means of deterministic models. Finally, detailed results obtained for a building with waffle slabs, which is a structural typology widely used in Spain, are included and discussed.     

Modeling the drainage and groundwater table above the collecting pipe through 2D groundwater models

In order to understand the effects of the landfill operation on groundwater flow behavior, 2D horizontal groundwater simulation model was carried out. The model saved the memory of computer and time consumption comparing with 3D groundwater flow model. However, the most difficulty is the assignment of collecting pipe boundary in the study site. Therefore, 2D vertical model was applied to calculate the change of groundwater table above the collecting pipe. This paper paid attention to examine the validation of the assignment of the collecting pipe boundary by applying the results of 2D vertical model. 2D horizontal model was coupled with the recharge model to solve the partial differential equation of groundwater flow. Finite difference method and iterative successive over relaxation were applied. The drainage volume of leachate collection was summed up in the whole landfill site and compared with the average volume of treated waste water. The study demonstrated that the results of 2D vertical model validated and can be applied to 2D horizontal groundwater flow simulation.     

The persistence of abnormal return on assets: an exploratory analysis of the performance of firms by country and sector

This study offers an exploratory statistical analysis of the persistence of annual abnormal returns across a sample of firms from different European Union countries. To this end, a hierarchical Bayesian dynamic model has been used that enables the annual behaviour of those profits to be broken down into a permanent structural component and a transitory component, while also distinguishing between general effects affecting the industry as a whole and specific effects impacting on each firm in particular. This breakdown of the behaviour of profits allows for a more accurate assessment of the relative importance of these fundamental components by country and sector. Furthermore, through the Bayesian approach, it is possible to test different hypotheses about the homogeneity of the dynamic behaviour of the aforementioned components with respect to the sector and the country where the firm develops its activity. We find that although both the industry and firm effects are significant, the latter are more important to explain the dynamic evolution of abnormal returns. Specifically, firm effects account for 68% of total variation of the abnormal returns and display a lower degree of persistence with adjustment speeds oscillating at around 34%, while industry effects only account for 9% and have adjustment speeds oscillating between 7% and 8%. However, this pattern is not homogeneous and depends on the sector and country in which the firm carries out its activity. These results highlight the need to take into account both aspects simultaneously in order to analyse the dynamic behaviour of abnormal returns. Copyright © 2014 John Wiley & Sons, Ltd.     

Some aspects in practical estimation of groundwater contaminant concentrations

Spatial distribution of groundwater contaminant concentration has special characteristics such as approximate symmetric profile, for example, in the transversal direction to groundwater flow direction, a certain ratio in directional propagation distances, etc. To obtain a geophysically appropriate semivariogram which is a key factor in estimation of groundwater contaminant concentration at desired locations, these special characteristics should be considered. Specifically, the concepts of symmetry and ratio are considered in this paper. By applying these two concepts, significant improvement of semivariograms, estimation variances, and final estimation results compared with the ones by conventional approaches which usually do not account for symmetry and ratio are shown using field experimental data.     

孔洞裂隙水二维流数值模拟的广义差分法

研究区地下水主要为玄武岩类孔洞裂隙水,水文地质模型概化为各向异性非均质,根据第四系玄武岩承压含水层中地下水的分布特征及流动规律,建立二维非稳定流数学模型,采用广义差分法对其求解.通过研究区井群对模型进行识别、验证.结果表明,计算模型与实际水文地质条件比较接近;计算水位与实测水位相吻合.为城市地下水可持续性管理提供科学理论依据.     

Prediction of concentration and particle size distribution in the flow of multi-sized particulate slurry through rectangular duct

The analytical model proposed by Karabelas [AICHe J. 23 (4) (1977) 426] has been modified and upgraded to predict the concentration profile and particle size distribution across the cross-section of rectangular duct for the flow of multi-sized particulate slurry. The predictions have been compared with the experimental data reported by Kaushal [Prediction of particle distribution in the flow of multi-sized particulate slurries through closed ducts and open channels, 1995]. The limitations of the original model have been identified and modifications incorporated to take into account the effect of solid concentration on settling rate and particle diffusivity. The predictions by the modified model are in good agreement with the experimental results.     

基于修正区间模糊Shapley值的“一带一路”PPP项目利益分配模型

多方合作的“一带一路”基础设施PPP项目是互联互通的基石,公平合理地分配项目利益则是保障其顺利实施的关键。为了构建科学的利益分配模型,考虑项目参与方组建的合作联盟预期收益为模糊数且分配时受多种因素影响,本文首先,基于区间模糊Shapley值构建“一带一路”PPP项目利益分配初始模型;然后,识别出利益分配影响因素并量化参与方的投入分担程度,据此修正初始的利益分配模型;最后,结合实际案例,将该模型与现存方法进行对比分析,结果显示本模型的可操作性更强,针对影响因素系数的测算更为精准,整体具有显著优势。     

Risk analysis techniques and their application to software development

The past decade has seen a dramatic change in the emphasis of software to hardware. Whereas a project may have comprised 80% hardware and 20% software, the reverse is now generally more realistic. This has resulted in a great deal of interest focusing around the areas of quality metrics and reliability growth applied to the software lifecycle. Risk analysis has to date seen many applications in the assessment of hardware but little in the software area. This paper reviews the risk analysis techniques that have been developed in a range of industries. Progress in this area has been most apparent in the chemical and nuclear power industries where probabilistic risk assessment has been used to estimate the total risk associated with the whole plant. A discussion of the appropriateness of the techniques to software safety assessment is included together with an outline of the methods currently being used to detect software faults. Suggestions are made for a new methodology in analysing software safety.     

Evaluación sísmica de los edificios de mampostería típicos de Barcelona aplicando la metodología Risk-UE

In this work, a study about the vulnerability and seismic damage of unreinforced masonry buildings is carried out. Three models of buildings representatives of the Eixample district of Barcelona have been chosen. The seismic vulnerability is evaluated by means of the Risk-UE methodology. The seismic demand is described by elastic project spectrum, in this case, defined by the Eurocode 8. Fragility curves are obtained from a nonlinear analysis, considering the capacity spectra. Expected seismic damage is gotten with the damage probability matrices, which indicate the occurrence probability of a damage state for a seismic demand given. The analysis of the buildings has been performed by TreMuri program by means of a macroelements model, which represents of a whole masonry panel. The buildings, here, analyzed are real and detailed structural drawings and reports have been used to model them. The results shown a considerable vulnerability in this type of buildings, therefore, in spite of the seismic hazard the expected seismic risk is significant.