遗传算法在结构损伤识别中的应用研究

结构损伤识别是结构系统在使用期间进行监测和维护的重要组成部分,而基于动态测试技术的结构损伤识别方法又是近来研究的热点。本文提出了一种基于改进遗传算法的结构损伤识别方法,主要改进包括:浮点编码、基于标准化几何分布排名的选择策略、最优保存策略、算术交叉算子、非均匀变异算子。在常规模态分析的基础上,以节点的残余力向量构造目标函数,提出了一种用于遗传搜索优化的新的目标函数形式。利用遗传算法重点进行了噪声条件下的结构损伤定位和定量研究,并用一平面桁架模型进行了数值模拟。结果表明:提出的方法不仅能够同时进行结构的损伤定位和定量计算,而且抗噪性能很好。最后,对方法应用中存在的一些问题进行了深入分析,给出了一些有益的结论。     

城市风暴潮灾害快速评估的模糊决策方法——以厦门市为例

综合考虑了反映风暴潮灾害的自然特征和社会属性的4个指标,将其作为评估指标,建立了基于模糊决策的风暴潮发生过程中城市灾害的快速评估模型,并以街道为最小评估单元,对厦门市进行了一次模拟风暴潮的灾害综合快速评估。由于模型考虑了少量具有代表性的因素,故能保证评估过程的快速性、评估结果的时效性,能为政府在有限的时间和资源下做出救灾减灾的优先工作策略提供决策依据。     

城市高温热浪调控机制模拟研究

在全球气候变暖和城市化加速发展的共同影响下,高温热浪事件频繁发生、日趋严重。为了分析屋顶亮化、城市绿化和地表增湿在调节城市热力环境、缓解城市高温灾害中的作用,本文选择了2013年8月的高温天气过程,利用耦合了城市冠层模式的WRF模拟系统,采用屋顶亮化、屋顶绿化和地表增湿3种不同的调控方案模拟分析其对城市热环境、湿度和近地面热量通量的影响,及其不同的降温效果和影响时段。研究发现:(1)3种调控方案通过改变城市地区的辐射过程或者能量平衡过程,降低白天尤其是正午时分的近地面气温,可有效的减缓夏季城市地区的高温热浪。(2)采用地表增湿方案,当城市街道表面含水层厚度从0mm增加到3mm时,潜热通量迅速增加,感热通量迅速减少,降温迅速。这说明在白天用较少水量多次对城市街道增湿,是一种显著降温的有效方法。     

铁路噪声对沿线居民环境影响综合评价方法的研究

铁路噪声扰民是铁路对居民生活环境不利影响的一个重要方面。本文利用大量实地调查和监测结果，应用铁路环境噪声声级计权人口分析评价了铁路对沿线居民的实际影响，并给出了评价示例。     

Mapping of noise risk zones derived from religious activities and perceptions in residential neighbourhoods in the Cape Coast metropolis,Ghana

Ambient noise levels emanating from religious activities in residential neighbourhoods are an emerging environmental problem that educes little attention from enforcement agencies and policy makers in Ghana. This paper set out to quantify religious noise exposure in urban residential neighbourhoods in the Cape Coast metropolis of Ghana. Subjective annoyance levels of residents in selected communities were determined. Noise risk zones were mapped using ARCGIS 9.3 software and surface interpolation for the data was carried out using inverse distance weighting. The results show that most (77 and 86 per cent) of the locations recorded noise levels that were above the Ghana Environmental Protection Agency maximum permissible limit for day and night, respectively. Pearson's correlation coefficient for day and night noise exposure shows strong association (0.714) at the 0.01 level. There is variability in the levels of noise for both day and night, which are rather high (standard deviation = 7.59477 and 7.94022, respectively). Generally, levels of noise exposure correlated with levels of annoyance of residents, except that the highest noise exposure was not recorded in the community where the annoyance level of residents was highest. Residential neighbourhoods within the study area largely experienced safe to tolerable levels of religious noise, although 5 per cent were within the high-risk zone. Given that the selected residential areas have high population densities, even when the dispersion of noise risk is spatially limited, it affects a large number of people who belong to different socio-economic classes.     

我国边疆城镇精细化管理技术研究∗

智慧城市的发展对城市安全提出了更高的要求,提升城市管理与应急反应水平是提高城市安全水平的重要保障。城市三维场景快速重建与精细化管理是智慧城市构建的重要支撑技术。针对我国边疆城镇地区社会稳定和公共安全管理的应用需求,提出了航天、航空、地面、室内外一体化的数据采集与处理方法,解决了基于高性能计算的大规模倾斜三维影像数据快速建模关键技术。以我国西部边疆典型城镇新疆库尔勒市为试验区,开发城市精细化管理系统,实现城市人口信息的精细化管理及突发事件应急响应预案的动态模拟等应用功能,验证了研究内容的合理性与实用性。     

Earthquake-strengthening policy for commercial buildings in small-town New Zealand

New Zealand introduced a seismic retrofitting policy in the wake of the catastrophic Canterbury earthquakes of 2010–11. The aim was to enforce seismic strengthening of earthquake-prone commercial buildings throughout the country. This study focuses on regional urban centres and the economic obstacles to strengthening their aging building stock. In investigating one town, Whanganui, we describe conditions, analyse cases, and identify incentives that apply equally to many other towns in New Zealand. We argue that incentives that suit high-growth, high-value major urban centres are a poor fit for the periphery. Around the world, many places need to upgrade their privately-owned building stock to protect it from disasters, while governments face similar challenges as they struggle to initiate the strengthening of commercial buildings. We analyse the current incentive schemes that aim to support the achievement of policy goals and suggest alternative incentive schemes that can be implemented to improve strengthening outcomes.     

基于GIS的乡镇洪涝灾害风险评估与区划技术——以山东省淄博市临淄区为例

基于乡镇气象资料历史序列的构建,利用AHP决策分析法和加权综合评价法,结合GIS空间分析技术,对山东省淄博市临淄区洪涝风险进行评估与区划。结果表明,临淄区洪涝危险性主要受洪涝频率影响,总体趋势是东北部高于西南部;洪涝灾害暴露性风险分布区域性较强,西部明显高于东部;脆弱性风险分布相对较分散,总体上北部地区脆弱性高于南部地区;防灾减灾能力北部地区强于南部。临淄区洪涝风险综合指数普遍较高,高值集中在人口、经济密度较高的临淄市区以及危险性较高的西北地区;风险指数受危险性影响较大;全区中、高风险的面积占总面积的69.2%。     

城市暴雨灾害的影响程度及对策研究——以长沙市为例

通过对近年暴雨资料、城市建成区平均高程数据和城市排水管网资料的考察,以及对城市暴雨灾害危险性、脆弱性、暴露性的分析,制定了适用于长沙市的暴雨灾害风险评估方法。利用该方法对长沙市现有建成区798个地块的暴雨灾害风险进行了评估,将其分为高风险区、中风险区、低风险区3个类别。在此基础上,总结了长沙市暴雨灾害风险区的分布规律,并提出了一系列对策措施,包括更新城市排水管网、建设地下集水库、建立雨水自排系统和建设紧急排涝系统等。     

基于贝叶斯随机评价方法的小城镇灾害易损性分析

为了准确评价小城镇灾害易损性所处的状态,进而为制定小城镇防灾减灾规划提供科学依据,提出了基于贝叶斯公式的小城镇灾害易损性随机评价方法。该方法通过计算小城镇灾害易损性单个指标属于某个评价级别的概率,由最大似然分类原则确定单个易损性指标的评价级别,进而采用最大加权概率原则推求其综合评价级别。通过实例计算分析,并与模糊评估方法、可拓物元评价方法进行比较验证,说明了该方法的可行性及其简单、实用的特点。     

Environmental hazards and waste management in Nsukka urban metropolis in Enugu State of Nigeria: how much are people willing to pay?

Solid waste management in Nsukka town in Enugu state of Nigeria has remained a major challenge despite the efforts of the state government through the Enugu State Waste Management Agency (ESWAMA). The current method whereby households dump refuse at designated locations by the road side to be cleared later has not yielded much improved sanitation of the town. In this study we propose an alternative waste management method that is believed to be superior to the status quo if properly managed. This study applies Contingent Valuation Method (CVM) to estimate the households’ willingness to pay (WTP) for this new method in order to ascertain its applicability in Nsukka urban. Data were collected from a sample of 500 households stratified according to major streets in the town. The results show that the mean WTP using different specifications of the model varies from N527.50 (about 2.68) to N530.90 (about 2.68) per month. The policy implication is that if the waste management agency adopts the proposed scenario and manages it well the average revenue realizable per month would be about N13,750,516 (about $69,800). The authorities can compare this with the cost of providing the service and see if it is worth the effort.     

The 1928 Eruption of Mount Etna Volcano, Sicily, and the Destruction of the Town of Mascali

In November 1928 there was an eruption of Mount Etna, Sicily, which led to lava largely destroying the town of Mascali, situated low on the eastern flank of the volcano. Destruction of the town took just over a day but there was an orderly evacuation of its inhabitants and, with help from the military, families were able to remove furniture and fittings from their houses. Evacuees were relocated to nearby towns staying with relatives, friends or in hired apartments. Rebuilding Mascali provided an opportunity for the fascist government of the time to demonstrate efficient centralised planning. A completely new town was built on a grid-iron plan with many of the buildings reflecting the 'fascist architecture' of the time. The town was complete by 1937 and housing condztzons were very advanced in comparison with other towns in the region. The 1928 eruption is important as it was the most destructive on Etna since 1669 when the city of Catania was overwhelmed. In terms of hazard and risk assessment the 1928 eruption demonstrates that lava can reach the lower flanks of the volcano within a short period after the onset of an eruption.     

基于FAHP法的城市社区应急准备能力评估

通过分析城市社区应急能力的影响因素,论述了城市社区应急准备能力评估指标集的建立方法和基于模糊层次综合评价法的评估模型构建方案,建立了城市社区应急准备能力评估模型,并结合实例进行了分析,为城市社区应急准备能力的定量综合评价提供了新思路。     

地震灾害下城市关键基础设施毁伤恢复力评估方法

为提高地震灾害后城市关键基础设施恢复力评估准确性,该文提出城市关键基础设施毁伤恢复力评估方法.分析城市关键基础设施在地震灾害中的响应特征,确定基础设施毁伤程度与地震灾害等级之间的关系;收集地震灾害信息,检测地震灾害等级,以此作为毁伤恢复力评估的重要指标;另外,结合毁伤恢复力的其他影响因素分析结果,构建恢复力评价指标体系...     

Exploring the risks of ineffective water supply and sewage disposal: A case study of Mexico City

This study proposes a method to evaluate the effectiveness of water management in providing a safe water supply and adequate sewage discharge and treatment for residents of Mexico City. This method also assesses the vulnerability of the city and its capacity to face or cope with potential threats generated by insufficient water supply and sewage extraction. Indices for analysing these parameters were estimated and the spatial distribution of the groups most affected was identified. According to the results of the models used, Mexico City inhabitants are mainly exposed to risk because of economic limitations rather than ineffective water management. However, some practices implemented by city authorities are increasing the population's exposure to risk. Consequently, in the future it may be necessary to modify the way water is supplied and how sewage is transferred from the city to the sea.     

城市土地工程能力评价的GIS方法

城市土地工程能力评价是城市进行合理规划,保持城市可持续发展的一项重要内容。本文以大庆市城区为例,分析了城市工程地质的特征,建立了城市工程地质信息系统,实现了工程地质空间特征的管理,分析及操作。通过Ｂａｙｅｓ决策方法,研究了空间地质特征的相关性,提出了用地理信息系统（ＧＩＳ）进行土地工程能力评价的方法,该方法能提高城市工程地质信息管理的层次,有助于城市土地工程能力评价工作方法的规范化和程序化。     

紫下大桥安全检测与评价方法研究

钢桥因具有跨径大、承载能力强、施工工期短等特点,被世界各国广泛采用,但在使用过程中,由于重载甚至超载车辆的反复作用、自然灾害的侵袭及交通事故等人为因素的作用,经常造成桥梁损伤和局部破坏,导致桥梁承载能力和耐久性的降低,甚至影响到运营的安全。本文建立了钢拱桥的健康检测和安全评价方法,采用防腐涂层厚度测定、结合强度测定、无损探伤和动静载荷试验等手段对紫下大桥健康状况进行了检测,采用不确定层次分析法对大桥进行了安全评价,提出了处理意见和措施,为既有钢拱桥的健康检测、评价和维护积累了有益的资料。     

城市地裂缝风险评价方法研究

随着人们应对灾害从过去的“被动救灾”走向现在的“主动预防”,风险管理成为防灾减灾领域一个热门话题。从危险性评价、易损性评价以及防灾减灾能力评价三个方面阐述了城市地裂缝风险评价内容,提出了城市地裂缝风险评价流程,探讨了城市地裂缝可接受风险水平。在机理分析的基础上给出了城市地裂缝危险性评价指标体系,根据城市用地类型开展易损性评价具有很好的可操作性。首次提出了城市地裂缝防灾减灾能力评价方法。     

荒漠化程度遥感定量化评价中的尺度问题

基于遥感手段的荒漠化程度定量化评价是当前遥感应用研究中的一个热点问题。在荒漠化评价中应当坚持主导性、综合性等原则。传统的荒漠化自动评价都是在离散的像元的尺度上进行的，未能综合考虑像元所处的环境，使得评价结果带有一定的片面性，评价结果图像中出现大量的噪音。若直接采用滤波方法消除这些噪音，则又会使评价结果偏离真实值。以地学原则为指导，在前人研究的基础上，探讨了以植被盖度和空间信息确定地理单元，提出了以地理单元为尺度进行荒漠化评价的方法。实践证明，基于地理单元的荒漠化定量化评价克服了传统方法的缺陷，评价结果更接近于地理事实。     

城市高架道路系统抗震性能分析

城市高架道路系统是城市交通系统的抗震薄弱环节,其震害不仅影响其自身的通行能力,通常还会影响高架道路下方的地面交通.对高架道路系统抗震性能的分析方法进行了系统阐述.采用系统分析方法对上海市内环高架道路系统进行了抗震性能分析,得到了震后系统通行时间延长值,而震后系统通行时间延长反映了系统通行能力的降低.