开放性公共场所疏散引导人布局优化研究——以上海市徐汇区滨江绿地空间为例北大核心CSCD

应急疏散引导在城市开放性公共场所安全建设中有着重要的意义。为解决应急疏散初期引导人的空间布局问题,论文考虑障碍物对通视性的影响、引导人的空间覆盖范围及距离衰减效应、可引导人员数量阈值等条件,基于粒子群算法和渐进覆盖模型,构建了一种新的开放性公共场所疏散引导人布局优化方法;并以上海市徐汇区滨江绿地空间为例,进行疏散引导人的布局优化,并基于疏散智能体模型,开展应急疏散引导模拟,比较优化前后的疏散效率,来验证该方法的可行性;同时,考虑到不同时间段人群分布的差异性,开展该区域内疏散引导人责任区的动态规划。实证结果表明:不同时刻研究区的疏散引导人需求量不同,与疏散人员数量成正比;疏散引导人布局优化后的疏散时间成本要远低于人为布设情景下的疏散时间成本;疏散引导人责任区的划分有助于在引导人数量有限的情况下,明确每个引导人负责的区域以及采取的日常安全防范方式。研究可为开放性公共场所疏散引导人空间布设提供决策依据,降低公共场所的潜在安全风险,促进城市公共安全建设。     

城市商圈应急疏散空间布局与路径优化——以广州上下九商圈为例

针对流动人口密集和商业集中的城市商圈应急疏散的特殊性,建立了城市商圈应急疏散研究框架。该框架主要包括应急疏散需求预测、应急疏散空间适宜性评价、应急疏散路径优化3个层面。通过3σ法、灰色关联法和熵权法、GIS、OD模型等技术,将研究框架应用于广州上下九商圈。结果发现:上下九商圈疏散人口和疏散场地需求较大,目前应急避难场所不能满足区域内疏散需求;适宜性强的紧急避难场所多为学校内操场用地,但有效避难空间极易受到建筑物倒塌影响,导致场地内避难空间不足;人口密集区大部分在选定紧急避难场所500 m服务范围和疏散用时在10 min内,但城市商圈路况复杂增加了疏散成本,同时降低了疏散效率。提出了应急避难场所的空间布局和疏散路径优化建议。     

风暴洪水灾害应急疏散方法研究——以浙江省玉环县为例

以浙江省玉环县为例,对超强台风(中心气压为915hPa,最大风速61.2m·s-1)风暴洪水灾害情景下的应急疏散方法进行了系统研究。首先,基于"点-线-面"洪灾避难思想和GIS空间分析技术构建应急疏散网络模型;其次,以疏散总时间最短为目标,并综合考虑避灾容量、交通拥堵、公平分配、资源节约等因素,求解最佳疏散路径;最后,根据疏散过程动态模拟结果,进一步优化路径选择,并编制应急疏散专题预案。结果表明:如果遭受915hPa超强台风袭击,将玉环县受淹危险区内的人群完全疏散到安全地带平均耗时647s(约11min),最长疏散时间不超过45min,可满足应急避难的实际需求。该疏散预案可为完善城市安全保障系统提供科学参考。     

基于应急疏散智能体模型模拟的城市避难所空间配置——以上海市静安区为例

城市应急避难所的空间配置一直是灾害防治和城市安全研究领域的热点问题。本文以城市居民尽快地,尽少拥挤地到达满足容纳需求的应急避难所为目标,整合遥感影像数据、高精度人口分布数据、交通路网数据和专家知识等数据,综合运用智能体模型和多准则决策方法,对城市避难所空间配置开展研究。本文设计了三类与应急疏散相关的智能体：政府智能体、避难所智能体和居民智能体,来实现应急疏散的模拟,并根据模拟结果支持应急避难所的空间选址和配置。选址方法上运用了多准则决策方法和权重敏感性分析,在选址高适宜区域内选定避难所的新建方案。以新的避难所空间布局和配置为条件,执行新一轮的应急疏散模拟过程,实现选址的循环优化,从而获得最终的避难所空间配置方案。本文以上海市静安区的应急避难所空间配置分析为案例,生成了该区域应急避难所的详细空间配置方案,该方案能帮助居民在尽少拥挤风险下尽快疏散到附近的避难所。本文提出的方法充实了中国城市避难所选址的相关理论与可操作性的技术基础,为其他地区开展避难所的配置工作提供借鉴与参考。     

城市新区教育设施可达性评价与空间优化——以深圳市坪山区为例

城市新区在发展过程中面临教育设施供给不足和不均衡的问题,可达性与空间优化方法能够为解决该问题提供科学依据。以深圳市坪山区为例,从供需关系出发,运用高斯两步移动搜寻法和改进的p-中位模型,探讨城市新区教育设施的可达性评价与空间优化,提出优化迫切度概念,分析得到教育设施优化区位和规模。结果表明:坪山区各层级教育设施可达性均存在明显空间差异;优化迫切度结果能够为设施配置的重点区域及优先次序提供依据;优化后各层级教育设施分布比较均衡,与人口分布较为契合;优化结果反映出相关规划标准存在不适用性,应注重规划标准差异化的研究。将城市教育设施空间布局评价和区位优化相结合,能为深圳市坪山区教育设施布局规划提供科学依据。     

城市社区空间应急疏散能力评价模型构建及其应用——以北京市交道口社区为例

以城市防灾空间中最基本的单元——社区空间为研究对象,对其应急疏散能力评价方法进行探讨。建立了基于现状空间分析的应急疏散能力评价模型,模型由应急疏散时间半径与应急疏散容量半径两个维度及应急疏散距离、道路有效宽度、道路集成度、应急疏散场所容量、社区人口密度5个因素构成。最后,通过GIS中的服务区分析及空间句法分析等技术,将模型应用于北京市交道口社区,找到交道口社区中应急疏散能力较弱的区域,为社区应急疏散空间的优化提供了依据。     

城市公共服务设施配置研究进展及趋向

公共服务设施是中国和谐宜居城市建设与人民美好生活愿望的重要构成。国内外城市公共服务设施配置的研究主题有所差异,国外研究主要关注公共服务设施配置的区位选择、可达性、空间公平和社会经济效应等方面,国内研究更加重视公共服务设施配置的优化布局、可达性、空间格局、社会分异、居民需求和满意度以及配置影响因素等内容。结合国内外研究现状的评析,论文认为中国城市公共服务设施配置研究需要加强公共服务设施配置的空间规律、社会公平、绩效评价和空间优化等方向研究。通过对国内外城市公共服务设施配置研究进展的理论总结与评述,以期促进中国城市公共服务设施配置的理论提升与科学实践。     

基于公平最大化目标的2020年北京市养老设施布局优化

北京市正快速步入老龄化社会,机构养老作为一种重要的养老模式,对其布局公平性和合理性的研究具有重要的科学和现实意义。本文首先预测了自然增长状态下2020年北京市老龄人口的空间分布,然后建立设施布局优化模型,该模型以各需求点到养老设施的可达性差异最小化为目标;并采用粒子群优化算法求解,对北京市养老设施进行以公平最大化为目标的布局优化。研究结果表明,在公平最大化的目标下,首都功能核心区和城市功能拓展区(即中心城区)所提供的机构养老资源不能完全满足本地需求。城市发展新区在满足当地的机构养老需求之外,还将为中心城区提供大量机构养老服务,生态涵养发展区在满足本地需求的基础上还可为其他地区提供少量机构养老服务。该布局导向与《北京市养老设施专项规划》提出的布局建议相一致,且符合中心城区用地紧张、郊区自然环境较舒适的现实情况。研究结果能为养老政策的制定提供科学建议,所采用的方法也能为其他类型公共服务设施的布局优化提供借鉴。     

基于供需关系的城市边缘区基础教育设施布局研究——以西安市长安区韦曲街道为例

运用Arc GIS空间分析方法,从设施的供需关系出发,在探究城市边缘区人口与基础教育设施分布特征的基础上,依据距离衰减规律和规模经济理论,分析设施布局中服务半径与门槛人口之间的制约关系,认为基础教育设施布局的核心问题是使供给密度与需求密度相匹配,从而构建了以供需密度为核心、兼顾服务半径与规模效益的城市边缘区基础教育设施布局规划模型。以西安市长安区韦曲街道为例,运用该模型对近期小学布局进行了研究,提出学校新建选址、扩建、撤并和增强可达性等规划建议,认为规划布局城市边缘区基础教育设施应当综合考虑服务半径与门槛人口,使设施供给密度与居民需求密度相匹配。     

空间公平导向的城市医疗设施优化配置模型研究

城市医疗设施合理布局及其空间公平性是地理学重要议题,最大可达性均等（MAE）模型是空间公平导向优化配置模型的重要进展,但已有研究对于模型空间公平测度指标的探讨仍较缺乏。从公共服务可达性及空间公平内涵出发,选出了国内外研究中常用的10种空间公平测度指标,对MAE模型的优化目标函数进行扩展。以深圳市医疗设施为例,对这些模型进行了应用和综合比较。研究发现：(1)从空间公平内涵来看,变异系数、基尼系数、平均绝对偏差和帕尔玛比值4个指标较适用于医疗设施空间公平研究。(2)从模型优化效果来看,基于方差、标准差、变异系数、帕尔玛比值、平均绝对偏差和泰尔指数的MAE模型表现较好。(3)综合来看,变异系数、平均绝对偏差和帕尔玛比值3个指标能够较好地测度医疗设施空间公平,以这3个指标为目标函数构建改进的MAE模型,能够提升模型优化效果。本文进一步发展了空间公平导向的设施优化配置模型,能够为医疗设施等公共服务设施布局规划提供科学方法支撑。     

Integrating multi-agent evacuation simulation and multi-criteria evaluation for spatial allocation of urban emergency shelters

The timely and secure evacuation of residents to nearby urban emergency shelters is of great importance during unexpected disaster events. However, evacuation and allocation of shelters are seldom examined as a whole, even though they are usually closely related tasks in disaster management. To conduct better spatial allocation of emergency shelters in cities, this study proposes a new method which integrates techniques of multi-agent system and multi-criteria evaluation for spatial allocation of urban emergency shelters. Compared with the traditional emergency shelter allocation methods, the proposed method highlights the importance of dynamic emergency evacuation simulations for spatial allocation suitability analysis. Three kinds of agents involved in evacuation and sheltering procedures are designed: government agents, shelter agents, and resident agents. Emergency evacuations are simulated based on the interactions of these agents to find potential problems, for example, time-consuming evacuation processes and road congestion. A case study in Jing’an District, Shanghai, China was conducted to demonstrate the feasibility of the proposed method. After three rounds of simulation and optimization, new shelters were spatially allocated and a detailed recommended plan of shelters and related facilities was generated. The optimized spatial allocation of shelters may help local residents to be evacuated more quickly and securely.     

基于疏散行为的震灾避难场所服务效率评价

科学评估避难场所的服务效率是提高城市应急水平的前提。传统对避难场所服务效率的评估多偏重于避难场所空间布局的合理性,缺少对避难者的空间布局和避难行为等避难需求的考虑,这会使评估结果造成偏差,从而容易引起资源配置的低效率。本文构建了多主体模拟模型,模拟避难者灾后对避难场所的选择、奔跑、安置等关键疏散行为过程,量化评估该地区避难场所服务效率。本文对比了两种量化评估指标在同一案例评估的差异性,一种是传统方法中空间可达性(服务半径覆盖率),一种是利用疏散行为模拟计算出的避难成功率;北京市海淀区的实证研究显示两项指标在同一案例区有巨大差异。这一分析结果显示,传统评估仅利用服务半径覆盖率这一指标来分析避难场所布局现状及规划的合理性存在不足。通过避难疏散行为的模拟发现,以下指标的使用有望辅助提高评估的真实性：①避难场所的利用效率。由于设施的利用效率不均衡,会导致避难场所超容或闲置的情况。在充分考虑避难场所的有效服务面积和服务人口的基础上,设计“人均避难面积”等反应利用效率的指标就显得十分必要。②避难标识系统的连通性。避难模拟的实验显示避难标识系统可能对避难者逃生疏散具有分流和引导作用,据此,避难场所与周边居民区的标识系统的连通性也是评价其服务效率的关键指标。     

基于WoS和Citespace的应急避难场所知识图谱和进展分析

以近30 年Web of Science 核心数据库收录的2472 篇应急避难场所相关文献为基础，首先统计发文数量时间分布和期刊分布，然后利用Citespace可视化软件，从发文作者、机构、国家、关键词和学科方向5个方面分别进行知识图谱分析。结果表明：近30年来应急避难场所研究发文呈现由缓慢探索、稳步发展向高速发展的阶段；发文期刊主要为自然灾害类、紧急医学类、工程技术类；研究作者群较多，学术交流较为紧密；美国和中国为发文量最多的国家；路易斯安那州立大学和中国科学技术大学是主要的发文机构；从关键词发现应急避难场所目标人群主要围绕灾害救援和社会弱势群体，研究视角从单一问题和事件开始向综合系统演变，研究方法从定性的方法模型转向动力机制和信息系统开发，研究内容则注重多学科交叉和微观尺度、重视案例实证和信息共享和强调应急避难场所管理；学科方向主要为工程学和公共环境与健康两个学科。在建设韧性城市的背景下，可借鉴国际经验来构建中国应急避难场所研究体系和管理。     

A new assessment model for evacuation vulnerability in urban areas

In the high-speed urbanization process of China, the urban population has been increasing significantly, leading to a high-density aggregation of population. However, the sharp increase in population density has not produced commensurate improvements in the road networks. On the contrary, the population increase induced a serious evacuation vulnerability, which cities experience during various hazards and catastrophic events. Therefore, research on evacuation vulnerability is important to urban planning. To assess the evacuation vulnerability, the optimal and worst scenarios should be considered because all possible evacuation plans occur between these extremes. However, most previous evacuation vulnerability studies are based on the worst-case scenario, only providing an upper bound of a potential evacuation assessment. To provide a more comprehensive theoretical basis for decision-makers to understand the consequences caused by all possible evacuations, this paper proposes an optimal evacuation vulnerability assessment model that provides the lower bound on potential evacuation difficulties. The model is solved by a stepwise spreading algorithm based on Graph Theory. Subsequently, to evaluate the effectiveness of the model, the study adopts the model to assess the evacuation capability of different road network topologies. A comparison with previous research was performed. The model was demonstrated in an application to the South Luogu Alley of Beijing, China. The significance of this paper is that the combination of our model with previous research may provide a more complete theoretical basis for an evacuation vulnerability assessment.     

A multicriteria spatial decision support system for solving emergency service station location problems

Earthquakes occurring in urban areas constitute an important concern for emergency management and rescue services. Emergency service location problems may be formulated in discrete space or by restricting the potential location(s) to a specified finite set of points in continuous space. We propose a Multicriteria Spatial Decision Support System to identify shelters and emergency service locations in urban evacuation planning. The proposed system has emerged as an integration of the geographical information systems (GIS) and the multicriteria Decision-Making method of Preference Ranking Organization Method for Enrichment Evaluation IV (PROMETHEE IV). This system incorporates multiple and often conflicting criteria and decision-makers’ preferences into a spatial decision model. We consider three standard structural attributes (i.e., durability density, population density, and oldness density) in the form of spatial maps to determine the zones most vulnerable to an earthquake. The information on these spatial maps is then entered into the ArcGIS software to define the relevant scores for each point with regards to the aforementioned attributes. These scores will be used to compute the preference functions in PROMETHEE IV, whose net flow outranking for each alternative will be inputted in ArcGIS to determine the zones that are most vulnerable to an earthquake. The final scores obtained are integrated into a mathematical programming model designed to find the most suitable locations for the construction of emergency service stations. We demonstrate the applicability of the proposed method and the efficacy of the procedures and algorithms in an earthquake emergency service station planning case study in the city of Tehran.     

The temporal hierarchy of shelters: a hierarchical location model for earthquake-shelter planning

The problem of emergency facility location is a critical component in evacuation planning. The emergence of geographic information systems (GIS) has provided a useful operational platform to assist this issue. A previously overlooked facet is the consideration of a hierarchical structure in the placement of emergency shelters. Due to the fact that survivors' needs change over time during post-disaster evacuations, shelters have now been categorized on a temporal scale based on their functions at different evacuation phases. This article proposes a three-level hierarchical location model for optimizing the placement of earthquake shelters by taking into account this temporal variance. The article not only scrutinizes the modeling procedure but also implements the model in a planning area with many real-world details. Based on the optimization results derived from a GIS context, we have found that the quality of the earthquake response procedure is not only dependent on the placement strategy of shelters, but more importantly on the financial constraints imposed on the planning and construction of these shelters. A discussion has been proposed to balance the trade-off between budget planning and evacuation efficiency. As the first attempt to model the hierarchical configuration of emergency shelters with specific focus on evacuees' escalating sheltering demands, this article will be of great significance in helping policy makers consider both the spatial and financial aspects of the strategic placement of emergency shelters.     

Microsimulation of large-scale evacuations utilizing metrorail transit

Public transit plays an important role in emergency evacuations, particularly for areas where public transit serves as a major commute mode for commuters. Microsimulation techniques provide great flexibility in assessing different scenarios in emergency situations. Combining GIS-based network analysis with microsimulation techniques, this study developed a framework to simulate emergency evacuations using rail transit. Applying the framework to a hypothetical attack on the Pentagon, this study investigated the performance of the Washington Metropolitan Area Transit Authority’s Metrorail for large-scale evacuations. A network-based analysis was performed to estimate the number of riders in association with each metro line and station. Using VISSIM, a multi-mode micro-simulation software package, this study integrated a pedestrian model with a Metrorail transit model to evaluate the performance of the Metrorail in the hypothetical evacuations. The simulation results suggested that if the potential of Metrorail transit is effectively utilized, it could be very useful resource during a large-scale evacuation. This study demonstrated the great potential and flexibility of microsimulation techniques for evaluating complex evacuation scenarios and strategies. The framework and approach used in this study can be applied to analyze other similar situations and help develop effective evacuation plans.     

Using reverse geocoding to identify prominent wildfire evacuation trigger points

Wildfire evacuation trigger points are prominent geographic features (e.g., ridge lines, rivers, and roads) utilized in timing evacuation warnings. When a fire crosses a feature, an evacuation warning is issued to the communities or firefighters in the path of the fire. Current methods for generating trigger buffers have limited utility because the resulting buffers are not explicitly tied to prominent geographic features, making it difficult to visually determine when a fire has breached a trigger point. This work aims to address this limitation by using reverse geocoding to identify prominent geographic trigger points that have more value to emergency managers. The method consists of three steps: 1) generate a trigger buffer using fire-spread modeling; 2) utilize online reverse-geocoding to retrieve geographic features proximal to the buffer boundary; and 3) identify the most prominent geographic features using viewshed analysis and compute the warning time each would offer given predicted fire spread rates to proximal communities. A case study of Julian, California is presented to identify prominent geographic trigger points that may have value to emergency managers in improving the timing of wildfire evacuation warnings in this region.     

Sensitivity of tsunami evacuation modeling to direction and land cover assumptions

Although anisotropic least-cost-distance (LCD) modeling is becoming a common tool for estimating pedestrian-evacuation travel times out of tsunami hazard zones, there has been insufficient attention paid to understanding model sensitivity behind the estimates. To support tsunami risk-reduction planning, we explore two aspects of LCD modeling as it applies to pedestrian evacuations and use the coastal community of Seward, Alaska, as our case study. First, we explore the sensitivity of modeling to the direction of movement by comparing standard safety-to-hazard evacuation times to hazard-to-safety evacuation times for a sample of 3985 points in Seward's tsunami-hazard zone. Safety-to-hazard evacuation times slightly overestimated hazard-to-safety evacuation times but the strong relationship to the hazard-to-safety evacuation times, slightly conservative bias, and shorter processing times of the safety-to-hazard approach make it the preferred approach. Second, we explore how variations in land cover speed conservation values (SCVs) influence model performance using a Monte Carlo approach with one thousand sets of land cover SCVs. The LCD model was relatively robust to changes in land cover SCVs with the magnitude of local model sensitivity greatest in areas with higher evacuation times or with wetland or shore land cover types, where model results may slightly underestimate travel times. This study demonstrates that emergency managers should be concerned not only with populations in locations with evacuation times greater than wave arrival times, but also with populations with evacuation times lower than but close to expected wave arrival times, particularly if they are required to cross wetlands or beaches.