Seismic vulnerability assessment of urban buildings and traffic networks using fuzzy ordered weighted average

Urban buildings and urban traffic network are considered as the vital arteries of cities which have particular effects especially after the crisis in the search and rescue operations. The aim of this study is to determine the vulnerability of urban areas especially, buildings and traffic networks using multicriteria geographic information systems and decisionmaking methods. As there are many effective criteria on the seismic vulnerability that they have uncertain and vague properties, the method of this paper is applying fuzzy ordered weighted average(OWA) to model the seismic vulnerability of urban buildings and traffic networks in the most optimistic and pessimistic states. The study area is district 6 of Tehran that is affected by the four major faults, and thus will be threatened by the earthquakes. The achieved results illustrated the vulnerability with different degrees of risk levels including very high, high, medium, low and very low. The results show that in the most optimistic case 14% and in the pessimistic case 1% of buildings tolerate in very low vulnerability. The vulnerability of urban street network also indicates that in the optimistic case 12% and in the pessimistic case at most 9% of the area are in appropriate condition and the North and NorthEast of the study area are more vulnerable than South of it.

Application of fuzzy optimization model in the evaluationof urban flood-waterloggedvulnerabilitybased on the synthetic weight ofgame theory

The evaluation of urban flood-waterlogged vulnerability is very important to the safety of urban flood control. In this paper, the evaluation of consolidated index is used. Respectively, AHP and entropy method calculate the subjective and objective weight of the evaluation indicators, and combine them by game theory. So we can obtain synthetic weight based on objective and subjective weights. The evaluation of urban flood-waterlogged vulnerability as target layer, a single variable multi-objective fuzzy optimization model is established. We use the model to evaluate flood-waterlogged vulnerability of 13 prefecture-level city in Hunan, and compare it with other evaluation method. The results show that the evaluation method has certain adaptability and reliability, and it＇ s helpfid to the construction planning of urban flood control.

Variable sets method for urban flood vulnerability assessment

On the basis of dialectics basic laws and mathematical theorems of variable sets,this paper proposes a variable sets method for urban flood vulnerability assessment.In this method,the comprehensive relative membership degree of multi-indices is represented by an index relative difference degree,which follows the characteristics of dialectical philosophy and mathematics.According to the quality-quantity exchange theorem,the relative difference degree of two adjacent levels(h and h+1),whose index standard interval values cross the boundaries,equals 0 in the urban flood vulnerability assessment.On the basis of the opposite unity theorem,the sum of relative membership degrees should be equal to 1 when indices lie in the adjacent degrees h and h+1.The variable sets method is proved to be theoretically rigorous and computationally simple.This paper takes 29 cities of Hunan province as an example to assess the urban flood vulnerability,and then compares the results from this newly developed method with the assessment results obtained from the fuzzy comprehensive evaluation and fuzzy set pair analysis methods.

A comprehensive assessment of urban vulnerability and its spatial differentiation in China

The urban vulnerability poses a serious challenge to achieving sustainable devel- opment. With the concentration of the population and the economy, cities must manage the higher frequencies and risks of various hazards and are becoming more vulnerable. Re- search on the assessment and regulatory control of urban vulnerability is of great significance for both urbanization quality improvement and sustainable development in China or other countries in the world. Because of the complexity of cities and vulnerability concepts, existing studies have focused on different aspects of urban vulnerability. And the research content of urban vulnerability is scattered and relatively independent, leading to a lack of comparability among the research data and resulting in tremendous difficulties in summarizing the conclu- sions through comparison of independent research data. Therefore the goal of this study was to construct urban vulnerability index （UV/） from the perspective of sustainable development that could assess urban vulnerability comprehensively. In this study, we selected 10 subin- dexes involving 36 specific parameters from four aspects （resources, eco-environmental sys- tems, economics, and social development） to construct a comprehensive index system. We also established the standard values of measurements. Then we take 288 prefecture-level cities in China as a study area and evaluate its overall urban vulnerability and its spatial differentiation. Results indicate that urban vulnerability of China has a remarkable spatial differentiation of both ＂gradient distribution＂ and ＂clustered distribution＂; the extent of urban vulnerability corresponds to city size, the bigger the city, the lower its vulnerability; re- source-based cities are more vulnerable than comprehensive cities; a city＇s economic growth rate does not reflect the extent of its urban vulnerability. Further, we offer a few suggestions to cope with urban vulnerability in China.

Multidimensional Model for Vulnerability Assessment of Urban Flooding: An Empirical Study in Pakistan

Urban flooding has become a regular phenomenon in many towns and cities in the Asia Pacific region over the past years. Professionals associated with disaster management and climate change are at the forefront of addressing urban flooding. To reduce flood risks,vulnerability and its components must be understood.Vulnerability assessment methods are diverse and complex, with a varied nature of understanding the key terms used in various contexts, and this diversity ultimately reflects on the interpretation of results in research settings.Diverse interpretations and definitions exist in the disaster risk and climate change literature, complicating the process of astute and comprehensive vulnerability assessment. The main purpose of this study was to quantify vulnerability indicators and develop a multidimensional model for vulnerability assessment. Vulnerability is explored through the lens of five dimensions: social, economic, physical/infrastructural, institutional, and attitudinal. This methodology is applied to urban flooding in Pakistan, to verify the proposed model. Three study sites in urban areas with different population sizes, situated in high-risk flood zones in the Punjab Province of Pakistan were selected for empirical investigation. A household survey was conducted, and indices were developed for each dimension based on welldefined indicators. The proposed methodology for vulnerability assessment was tested and found operational. This method can be replicated irrespective of spatial scales and can be modified for other disasters by streamlining hazard specific indicators.

Simulating Sustainable Urban Development by Incorporating Social-ecological Risks into a Constrained CA Model

A key solution to urban and global sustainability is effective planning of sustainable urban development, for which geo-techniques especially cellular automata(CA) models can be very informative. However, existing CA models for simulating sustainable urban development, though increasingly refined in modeling urban growth, capture mostly the environmental aspect of sustainability. In this study, an adaptable risk-constrained CA model was developed by incorporating the social-ecological risks of urban development. A three-dimensional risk assessment framework was proposed that explicitly considers the environmental constraints on, system resilience to, and potential impacts of urban development. The risk-constrained model was then applied to a case study of Sheyang County, Jiangsu Province in the eastern China. Comparative simulations of urban development in four contrasting scenarios were conducted, namely, the environmental suitability constrained scenario, the ecological risk constrained scenario, the social risk constrained scenario, and the integrated social-ecological risk constrained scenario. The simulations suggested that considering only environmental suitability in the CA simulation of urban development overestimated the potential of sustainable urban growth, and that the urbanization mode changed from city expansion that was more constrained by social risks to town growth that was more constrained by ecological risks. Our risk-constrained CA model can better simulate sustainable urban development; additionally, we provide suggestions on the sustainable urban development in Sheyang and on future model development.

基于OWA算子赋权和后悔理论的城市水资源脆弱性评价

为解决城市水资源脆弱性评价方法主观性过强、未考虑自然人有限理性和后悔规避心理行为特征造成评价结果失真的问题,提出基于OWA(有序加权平均)算子赋权和后悔理论的城市水资源脆弱性评价方法。运用DPSIR模型,从驱动力、压力、状态、影响、响应5个方面构建29个评价指标;采用OWA算子对决策数据重新排序,充分考虑数据位置和大小,弱化极端决策数据对权重的负面作用;选择后悔理论中决策数据效用值和理想效用值间的差异性作为评判专家主观性的依据,实现决策主观数据的客观化,从而提升评价结果的客观性。最后对郑州市2017—2022年水资源脆弱性进行评价,并将评价结果与AHP(层次分析法)和后悔理论、OWA算子和模糊数学的评估结果对比分析。结果表明:基于OWA算子赋权和后悔理论的城市水资源脆弱性评价方法评价结果与其他方法评价结果基本一致,均认为郑州市水资源重度脆弱,但该方法评价结果相对误差更小,更贴近实际情况,可更好地用于城市水资源脆弱性评价。

基于电-水跨层耦合模型的城市电网脆弱性评估

为更好地揭示极端场景下城市电网对供水网的复杂影响,该文考虑城市电-水主干网及用户侧的耦合特征,构建城市电-水跨层耦合模型,并分析计及供水服务损失的电网脆弱性。首先,建立城市电网及供水网的拓扑和能流模型;其次,分析高压配电变电站与泵站、中压配电变压器与用户侧高层建筑水泵两种不同层级的电-水耦合关系,建立城市电-水跨层耦合模型;再次,考虑蓄意攻击场景下电网的切负荷应急调度策略,并分析城市电-水三层故障传导效应,量化和评估高压配电网侧故障对供水网用户侧供水量的影响;最后,以某市级电网和供水网为例,评估蓄意攻击场景下计及供水服务损失的城市电网脆弱性,并分析其受电力负荷与需水量时序变化的影响。研究结果能为考虑电-水故障传导效应下识别电网薄弱点,提升城市韧性提供参考。

城市泥石流易损性评价

本文探讨了城市泥石流易损性评价的系统方法,该方法包括:易损体类型划分,易损体数量调查统计,评价模型构建和核算易损体价值等主要内容。目前对地观测技术可以更精确地用于城市泥石流易损性分析,并对城市居民房屋、基础设施和农业用地等进行易损性评价。本研究以美国高分辨率的"快鸟"卫星影象为数据源,完成了研究区的土地覆盖类型遥感解译,应用地理信息系统提供的统计和分析工具,完成了研究区不同土地覆盖类型的城市泥石流易损性计算和评价。

上海城市系统洪灾脆弱度评价

洪灾脆弱度评价是把洪水灾害与风险研究紧密联系起来的重要桥梁。沿海城市地位的重要性和面临自然灾害的高脆弱性,使沿海城市自然灾害研究受到世界各国政府的普遍关注。与国外相比较,国内对沿海城市系统洪灾脆弱度研究较少。为了进行准确的洪水灾害风险评价,从而更好地制定城市防洪减灾的对策和措施,城市系统的洪灾脆弱度研究就显得十分重要。本文基于复合生态系统理论,从系统的角度出发,分别构建了上海城市系统洪灾自然子系统、社会子系统和经济子系统脆弱度评价指标体系,并采用层次分析法和熵值法结合确定指标的组合权重,兼顾主客观赋权优点,提高评价结果的科学合理性。最后对上海城市系统洪灾脆弱度进行模糊综合评价,评价结果与实际情况基本相符。本文研究结果可为上海市沿海地区土地利用规划和社会经济发展规划提供参考依据。

中国城市地震灾害危险度评价

应用中国历史上发生的M≥4的6759条地震信息和2000年中国672个城市的有关信息,采用中国城市近源地震等效震级M和城市地震灾害承灾体易损性指数CV,构建了中国城市地震灾害危险度指数WX,并编制了相应的分布图。研究表明:中国41.82%的城市历史上发生过M≥4的近源地震。CV高值城市的分布与我国城市群、城市带的分布并不一致。华北地区、台湾岛地区是我国城市高危险度的高密集区,其次是福建广东沿海、云南省、新疆天山山脉等地区。WX值在3.0以上的37个城市应作为国家减轻地震灾害的重点城市。

中国城市主要自然灾害风险评价研究(英文)

本文依据灾害系统理论和中国自然灾害数据库,构建了反映城市承灾体的综合城市化水平(CL)指标,并在此基础上得到城市脆弱性水平指数。考虑对城市具有结构性破坏和易于造成交通灾情的主要灾种,即水灾、地震、滑坡—泥石流、台风、沙尘暴,构建了反映城市主要致灾因子的综合自然灾害强度(QC)指标,并得到城市综合自然灾害强度指数。据此,在定性分析的基础上,通过半定量计算,将中国城市主要自然灾害风险划分为高风险、较高风险、中等风险、较低风险、低风险5个等级,编制了中国城市自然灾害风险评价图,并对灾害链的综合风险评价作了进一步的探讨。

城市供水管网脆弱性评价研究进展

脆弱性评价有助于甄别城市供水管网的薄弱环节,确定合理的风险削减措施,保证供水安全。阐述脆弱性的有关定义及其与风险的联系与区别,回顾城市供水管网脆弱性评价的发展历程,介绍几种脆弱性评价方法的基本原理、优缺点及适用范围,并按不同评价思路对国内外使用的主要脆弱性评价方法进行分类总结。研究发现,目前尚未形成统一的脆弱性概念及切实可行的评价方法,今后应不断完善和整合各类方法,以定量和通用为核心,使城市供水管网脆弱性评价方法更为实用、有效。

基于物元可拓模型的高原盆地城市水源地脆弱性评价

水源地脆弱性评价是高原盆地城市水源地科学保护和生态恢复措施制定的基础。以高原盆地城市水源地脆弱性评价指标体系为基础,运用物元方法和可拓理论构建了高原盆地城市水源地脆弱性物元可拓模型,并实例对云南省9个高原盆地城市水源地脆弱性进行了评价。评价结果表明:信房、北庙两水源地处于轻度脆弱性状态;云龙、松华坝、潇湘、九龙甸、东风等水源地处于中度脆弱性状态;菲白、渔洞等水源地处于高度脆弱性状态。9个水源地对不同评价指标的脆弱程度也各不相同。评价结果与水源地实际情况相符。

城市泥石流风险评价探讨

探讨了城市泥石流风险评价的系统方法,该方法包括泥石流扇形地危险区划、城市易损性分析和城市泥石流风险评价三个主要内容。泥石流堆积扇危险区划是基于数值模拟计算出的泥深和流速分布图进行叠合完成的。以美国高分辨率的“快鸟”卫星影像为数据源,完成了研究区的城市土地覆盖类型遥感解译,在此基础上完成了城市泥石流易损性分析,应用地理信息系统提供的统计和分析工具,完成了研究区泥石流风险评价。该风险区划图可用于指导对泥石流易泛区的不同风险地带的土地利用进行规划和决策,从而达到规避和减轻灾害的目的,也为生活在泥石流危险区的城市居民提供有关灾害风险信息,以作避难和灾害防治的依据。

四川省21市州城市自然灾害脆弱性评估研究

城市自然灾害脆弱性评估,是加强城市防灾减灾能力建设的基本前提。通过对自然灾害脆弱性相关文献进行回顾梳理并结合四川区域特色,构建出城市自然灾害脆弱性评价指标体系。运用主成分分析(principal component analysis,PCA)和逼近理想排序法(technique for order preference by similarity to an ideal solution,TOPSIS),对比分析了四川省21市州的城市自然灾害脆弱性。结果表明,川西北经济区城市灾害脆弱性程度最为严重,成都经济区灾害脆弱性程度最低,大部分经济区下辖市州的灾害脆弱性状况参差不齐。四川省各地存在明显的区域性城市灾害脆弱性差异。

城市埋地天然气管道系统的脆弱性评价模型及其实例应用

脆弱性评价是系统风险评估的新方法,具有理论成熟、指标全面,结果贴合等优点。在对天然气管道风险研究基础上,建立起适合城市天然气管道系统的脆弱性评估指标体系。结合城市天然气管道脆弱性指标的取值特点,选择模糊综合评判方法,建立城市天然气管道系统的脆弱性评估数学模型,实现系统脆弱度计算和脆弱等级确定。并对北京市某段次高压天然气管道的指标进行调研取值,带入模型进行该管道的脆弱性评价,实现模型的实例应用和效果检验。

城市道路GNSS脆弱性评估技术

全球卫星导航系统(global navigation satellite system,GNSS)在交通领域应用广泛,其服务性能的可靠性受到交通用户日益增长的关注.但是,由于系统故障、电离层闪烁、多路径效应、电磁干扰等脆弱性因素的存在,GNSS存在固有脆弱性,它影响GNSS的服务性能,甚至给用户带来巨大风险.当GNSS服务性能受到脆弱性因素干扰时,评估GNSS脆弱性,并且为用户提供及时的脆弱性告警,可以有效降低脆弱性因素对用户服务性能的影响.为评估不同城市道路环境下的GNSS脆弱性,在现有GNSS脆弱性评估算法的基础上,针对城市道路环境的特点,提出了相应的GNSS交通应用脆弱性评估指标;并采用基于信息熵权的数据融合算法,计算导航场景距正负理想场景的距离,实现了多个导航场景的脆弱性评估.路测实验表明,隧道、城市峡谷、林荫道和开阔路段的脆弱性依次降低,该方法所选取的脆弱性评估指标和采用的脆弱性评估算法可满足城市道路GNSS脆弱性评估需求.

城市设施恐怖袭击风险分析的方法论基础

由于恐怖袭击本质上的高度随机性,很难纯定量地估算概率,恐怖袭击风险的预测和减缓成为安全科学的新课题.本文依据经典的风险理论,探究易受攻击性和损失严重性的概念及其表征参数, 并通过易受攻击性和损失严重性等级矩阵确定城市设施遭恐怖袭击的风险水平.分析结果有助于合理配置防卫资源,有效减缓恐怖袭击可能造成的损失影响.

基于城市用地单元的自然灾害风险评估概念模型

为使城市土地利用规划与灾害风险管理更好地结合,从城市规划的基础单元———城市用地系统出发,提出基于城市用地单元的区域综合自然灾害风险评估的概念模型。基于城市用地单元的灾害风险评估,包括城市土地利用单元上潜在致灾因子及承灾体自然脆弱性相结合的灾损风险评估,以及人口、经济、社会因素等所引起的社会脆弱性评估2个方面。通过耦合矩阵,得到5个等级的灾害风险。其中,灾损风险与脆弱性均较高的城市用地单元或区域应得到高度关注。基于城市土地利用单元的灾害风险评估模型的应用关键,在于建立城市用地单元的数据库。提高基础数据的精度,有助于提高评估结果的精度。