Spatial Accessibility to Shopping Malls in Nanjing,China:Comparative Analysis with Multiple Transportation Modes

This study attempts to evaluate the rationality of the spatial layout of shopping malls and identify the urban area with poor shopping mall accessibility,as well as to provide a reference and assist decision-making for planning.Using the case of Nanjing,China,this study developed a method to evaluate the accessibility of shopping malls by three transport modes(car traffic,public transit,and bicycle).Specially,we divide the urban space into a regular hexagonal grid and harvest the total travel time from each of 7204 hexagon centroids to each of 129 shopping malls using the Baidu Internet map.The door-to-door travel time approach is used to evaluate all travel stages(walking,waiting,transfer,and transportation)based on travel time calculations.We further divide the shopping malls into two levels(super-regional and regional)based on the Dianping App’s information and develop the indicator of accessibility to shopping malls:the number of shopping malls within tolerance time thresholds and apply the closest facility and cumulative opportunities methods to measure accessibility scores.The results show that the accessibility estimations vary greatly with transport modes.The accessibility of shopping malls presents a concentric ring trend centered on the city center under the car traffic and bicycle modes.And public transit accessibility tends to axially extend due to the topology of bus routes and metro lines.In particular,we observe that the accessibility of shopping malls in Nanjing has an uneven spatial distribution pattern,with high accessibility values in the central urban areas and lots of underserved areas in urban fringe regions.Based on the accessibility measurements,we finally map the poor accessibility area and propose corresponding implications for urban planning.

Testing of relationships among spatial accessibility,property characteristics and property value

A novel hedonic model based on spatial accessibility is proposed.This model changes the traditional planar hedonic model from two dimensional to three dimensional(3 D).A 3 D model through space syntax and quantum geographic information system platform was developed.Then,this model was tested through an analysis of 174 residential areas in Tianjin’s central district.Accordingly,the impact of 3 D location characteristics on the property value was examined.The results suggest a positive correlation between spatial accessibility and property value on a city-wide scale.Mass transit may exert negative influences,such as traffic noise and air pollution.On submarket scales,the property value may be influenced by urban functions,historical background,and street layout.The negative correlation between the bedroom number and price reflects a higher real estate market investment value in the Heping District and the high demand for small and medium-sized houses in the Hongqiao and Hedong Districts.This study provides insights for improving neighborhood plans and housing design,and policy making concerned with promoting balanced progress of social,economic,and spatial priorities.

Assessing the Spatial Equality of COVID Testing Sites Maintaining Zero COVID Policy

Rapid and timely testing is essential to minimize the COVID-19 spread. Decision makers and policy planners need to determine the equal distribution and accessibility of testing sites. This study mainly examines the spatial equality of COVID-19 testing sites that maintain a zero COVID policy in Guangzhou City. The study has identified the spatial disparities of COVID testing sites, characteristics of testing locations, and accessibility. The study has obtained information on COVID testing sites in Guangzhou City and population data. Point pattern analyses, Euclidian distance and allocation, and network analyses are the main methods used to achieve the research objectives, and 1183 total COVID testing sites can be recognized in Guangzhou City. Results revealed that spatial disparities could be noticed over the study area. Testing locations of Guangzhou City are highly clustered. The most significant testing sites are located in Haizhu District, which has the third largest population. The highest population density can be identified in Yuexiu District. However, only 94 testing sites are located there. According to all the results, higher disparities can be identified, and a lack of testing sites is located in the north part of the study area. Some people in the northern part have to travel more than 10 km to reach a testing site. Finally, this paper suggests increasing the number of testing sites in the north and south parts of the study area and keeping the same distribution, considering the area, total population, and population density. This kind of research will be helpful to decision-makers in making proper decisions to maintain a zero COVID policy.

Spatial Differentiation and Influencing Mechanism of Medical Care Accessibility in Beijing:A Migrant Equality Perspective

Spatial equality of access to basic public services, especially medical care services which are directly related to life safety, is the first step to achieve the goal of equalization of basic public services for all the people proposed by central government of China. Using the spatial analysis and the statistical analysis, this study evaluates the spatial differentiation of medical care facilities accessibility by constructing STT(Shortest Travel-Time) and SAI(Spatial Accessibility Index). And then this study explores the neighborhood effects on the medical care facilities accessibility in Beijing, with a particular focus on the effect of neighborhood migrant proportion by constructing spatial dependent regression model. The spatial accessibility analysis of medical care facilities show that the spatial distribution of medical care facilities was basically consistent with administrative regions but not with population demands. Bivariate LISA cluster maps identify that suburban areas are the overlapped clusters of high percent of migrants and limited medical care services. This is associated with the public service allocation rule in China, which stresses equality within urban areas and within rural areas but overlooks equality between urban areas and rural areas; and stresses local resident demands but overlooks migrant demands. To estimate the effects on medical care accessibility of neighborhood migrant proportion, spatial dependence models are applied due to spatial dependence of accessibility of medical care facilities. The regression results show that neighborhoods with high percent of migrants, even conditioning on neighborhood SES, are related to limited spatial accessibility of medical care services. Besides neighborhood characteristics, another important factor influencing spatial accessibility of medical care services is the process of spatial spillover effects. This indicates that the attenuate accessibility of medical care services for migrants is not only because of their own constraints but also because of their proximity to other disadvantaged neighborhoods. Therefore, it is urgently needed to increase the medical facilities in the suburban areas, to take into account migrants' demands and to reduce residential segregation between local residents and migrants for local governments to achieve the goal of equalization of medical care service.

Transport Accessibility and Spatial Connections of Cities in the Guangdong-Hong Kong-Macao Greater Bay Area

Based on geographic information system(GIS) spatial analysis technology, the spatial pattern of raster grid transport accessibility for the Guangdong-Hong Kong-Macao Greater Bay area was studied and the states of spatial connectedness were simulated using highway passenger transport, railway passenger transport, port passenger transport and aviation passenger transport data. The result shows that transport accessibility within the Guangdong-Hong Kong-Macao Greater Bay area costs ‘one hour’ and the spatial distribution of accessibility in the area presents clear ‘core-periphery’ spatial characteristics, with Guangzhou, Foshan, Shenzhen constituting the core. The transport accessibility of Guangdong-Hong Kong-Macao is high. Average accessibility of urban nodes as measured by travel time is 0.99 h, and the areas accessible within 1.42 h occupy 79.14% of the total area. Most of the areas with the lowest accessibility are found in the peripheral area, with the worst accessibility being 4.73 h. Compared with the west-side cities, the economically developed east-side cities of the Guangdong-Hong Kong-Macao Greater Bay area have higher connectivity with roads, railways, ports, and aviation transport. Guangzhou, Foshan, Zhuhai, Shenzhen, Hong Kong and Macao are closely linked. The higher the accessibility, the closer the intercity connectedness.

Media Access with Spatial Reuse for Cooperative Spectrum Sensing

The increasing interest for wireless communication services and scarcity of radio spectrum resources have created the need for a more flexible and efficient usage of the radio frequency bands. Cognitive Radio (CR) emerges as an important trend for a solution to this problem. Spectrum sensing is a crucial function in a CR system. Cooperative spectrum sensing can overcome fading and shadowing effects, and hence increase the reliability of primary user detection. In this paper we consider a system model of a dedicated detect-andforward wireless sensor network (DetF WSN) for cooperative spectrum sensing with k-out-of-n decision fusion in the presence of reporting channels errors. Using this model we consider the design of a spatial reuse media access control (MAC) protocol based on TDMA/OFDMA to resolve conflicts and conserve resources for intra-WSN communication. The influence of the MAC protocol on spectrum sensing performance of the WSN is a key consideration. Two design approaches, using greedy and adaptive simulated annealing (ASA) algorithms, are considered in detail. Performance results assuming a grid network in a Rician fading environment are presented for the two design approaches.

城市洪涝应急响应能力评价及优化研究

在气候变化和全球化的背景下,极端降水事件及其导致的洪涝灾害频发。为准确评估暴雨内涝影响下的城市应急服务水平,基于InfoWorks ICM构建了城区内涝模型,利用ArcGIS中的最快路径法评估了医疗、公安、消防的空间可达性,利用基尼系数评估了公共应急服务相对幼儿园分布的合理性,采用最大覆盖算法对医疗、公安、消防的分布进行了优化,并基于研究区的情况进行了分析。结果显示:研究区的医疗、公安、消防相对幼儿园的基尼系数随着降雨重现期的增加而增大;对研究区的医疗、公安、消防分布优化前,这些部门的分布不尽合理,其15 min内的应急服务可达性不能满足应急救援要求,研究区应急响应资源相对幼儿园缺失严重,相对来说,医疗应急响应缺失最为严重;对研究区的医疗、公安、消防分布优化后,这些部门相对于幼儿园的基尼系数普遍在0.400以下,医疗和公安的应急服务即使在百年一遇洪涝加晚高峰情景下仍可以在15 min内覆盖40%的研究区面积,消防可覆盖70%的研究区面积,医疗、公安、消防的分布相对合理。本研究为中国城市洪涝灾害应急响应能力评价提供参考。

Spatial variation of the relationship between transport accessibility and the level of economic development in Qinghai-Tibet Plateau, China

As an important component of China’ transportation systems, for a long time, the insufficient performance of transport in QinghaiTibet Plateau(QTP) was a bottleneck restricting the economic growth and social development in this area. Nevertheless, the implementation of the western development strategy has accelerated the preliminary construction of comprehensive transport network since 2000. Due to the large area and significant geographical heterogeneity, there is a growing need to understand the relationship between transportation and economic development based on the perspective of spatial difference. By using GIS-based raster analysis and Geographically Weighted Regression(GWR) model, we investigated the spatial-temporal distribution of highway, railway and airport accessibility, respectively, and estimated the correlation and heterogeneity between transport accessibility and the level of economic development. Results revealed that:(1) Transport accessibility in the QTP improved by 53.38% in the past 15 years, which is specifically embodied in the improvement of both highway and railway.(2) Accessibility presented prominent differentiation in the space, increasing from west to east and reducing with the rise of elevation, specifically, the best accessibility area of the highway is below 4000 m above sea level, while the area with an altitude of over 4000 m has the lowest aviation time cost.(3) In general, the long weighted average time cost to critical transport facilities posed significantly negative effect on county economic growth in QTP, more positively, the adverse effect gradually weakened over time.(4) Obvious heterogeneity exists at the influence of different transport accessibility factors on the level of economic development, reflecting both in the horizontal space and altitudinal belt. Therefore, region-specific policies should be addressed for the sustainable development of transport facilities as well as economy in the west mountain areas.

Use of Spatial Analysis to Assess Geographic Accessibility of Community Pharmacies in São Mateus

Pharmaceutical services contribute to the rational use of medicines by ensuring the provision of appropriate, safe and effective pharmacotherapies. Thus, it is important to investigate whether the geographical distribution of pharmacies causes inequalities in access in countries like Brazil, where there is no federal law regulating the opening of new establishments (in contrast to many European countries). This study analyzed the accessibility of community pharmacies in the city of Sao Mateus, Espírito Santo, Brazil. The authors obtained the geographical coordinates of pharmacies and healthfacilities, which scanned and georeferenced the study area. The 40 pharmacies included in the spatial analysis presented a heterogeneous distribution, with the existence of neighborhoods with an accumulation of pharmacies and others with no pharmacies. The authors found that only 43.7% of the study area received pharmaceutical service coverage, when buffer zones of 350 meters are incorporated, and that most of the districts have a minimum distance of 100 meters between health facilities and pharmacies. It was concluded that the use of GIS proved to be very suitable for analysis of pharmaceutical services, enabling knowledge of the local situation and serving as a stimulus for future studies.

江西省养老机构空间分布格局及可达性研究

目的:评估江西省养老机构空间可达性,为江西省养老机构优化配置提供建议。方法:基于改进两步移动搜索法测度江西省养老机构空间可达性,并采用局部空间自相关分析法、基尼系数评价其适老化及公平性,运用空间误差模型对养老机构可达性进行机制分析。结果:江西省养老机构可达性整体上呈现中部向边缘降低、西高东低的空间格局;南昌市中部区域、赣州市章贡区中部呈现低供给、高需求的特征;在公平性上,江西省养老机构空间分布整体上处于相对合理的水平;老年人口、人均GDP、空气质量指数、路网密度与平均海拔对养老机构可达性具有显著正向影响。结论:江西省养老机构可达性空间差异较为明显,适老化发展水平有待进一步提高,南部与北部区域的养老机构空间分配差距较大,应加强区域之间的合作,促进地区间养老资源配置的协同发展。

基于矩阵特征分解的中原经济区高铁发展分析

针对基于位置的空间可达性研究中位置空间成本矩阵存在缺值导致可达性指标无法计算的问题,提出以矩阵特征分解作为替代方法。基于12306网站和网络地图在线服务取得旅行时间成本矩阵并转换为空间权重矩阵,以矩阵特征分解得到的优势度指数作为基本评价指标对中原经济区2017—2021年间的高铁发展进行分析和评价。结果表明矩阵特征分解法是评价部分矩阵元素缺值时空间可达性评价的一种有效替代方法, 2021年中原经济区高铁发展空间集聚水平比2017年略下降,南北向和东西向“十”字交叉格局有弱化趋势,同时高铁发展没有显著的空间不均衡现象,但某些高铁发展水平较低,且在研究时段内受益较少的地级市单元在今后的高铁规划中应给予重点关注。

城市紧凑度对城市公共服务设施空间可达性的影响

高品质公共服务设施体系的建设是打造宜居城市的基础性工程,可达性已经成为我国基本公共服务供给侧结构性改革的两大目标取向之一。目前我国城市发展中存在城市紧凑程度恶化与公共服务设施空间可达性状况不佳并存的局面,从城市空间形态这一重要城市整体特性视角研究城市公共服务设施可达性对于优化城市公共服务设施空间布局具有重要意义。以中国地级及以上城市的三类主要公共服务设施为考察对象,量化测度城市公共服务设施空间可达性,在此基础上实证分析城市紧凑度对城市公共服务设施空间可达性的影响,以及对不同类型设施的异质性影响,并检验公共服务设施规模分布和地方财政自主权对上述影响过程的调节效应。实证结果表明,城市紧凑度对城市公共服务设施可达性的影响呈现“U”型,目前多数城市处于U型曲线的上升阶段,高财政自主权强化了紧凑城市建设对于公共服务设施的挤出效应,而设施规模越分散,城市紧凑度对公共服务设施空间可达性的几何正向影响效果越弱。

基于改进高斯两步移动搜索法的西南山地乡村居民医疗设施可达性评价——以重庆市九龙坡区为例

近年来,乡村医疗资源的数量和质量都有显著提升,但不同地区乡村居民在获得医疗机会、就医成本等方面存在较大差异,医疗设施布局不合理问题仍存在。医疗设施可达性作为衡量医疗设施空间布局是否合理的关键指标,为解决医疗资源分配不合理和改善医疗资源分配不公等问题提供了重要依据。针对传统高斯两步移动搜索法(Gaussian-Based 2SFCA)对于山地乡村地区医疗资源可达性在供给与需求思考不足的问题,将其进行改进,从而更为科学客观地评价可达性。研究选取重庆市九龙坡区乡村地区为研究对象,借助Arcgis平台分析乡村医疗设施供需情况,引介改进高斯两步移动搜索法分析设施可达性,在此基础上,借助SPSS软件进行K聚类分析,揭示乡村医疗设施可达性影响因素。研究发现:第一,各类医疗设施的可达性数值综合层面上的高可达性区域主要是由于临近医疗资源高供给能力的县综合医院和乡镇卫生院所贡献的,而村级医疗设施对综合可达性空间差异影响较小;第二,山地乡村地区公共医疗设施配置存在医疗资源与人口分布的空间不匹配的情况,主要体现在村级医疗设施;第三,区域可达性水平与交通通达性高低没有必然联系,受人口需求(人口规模、人口密度)、医疗设施供给服务能力及分布的影响更大。最后针对不同可达性区域提出优化策略。本研究为西南山地乡村地区医疗设施可达性评价提供了一套具有实践操作性的方法体系。

The Analysis of Spatial-Temporal Evolution of City Accessibility Based on Highway Network in Henan Province in China

Accessibility is an important tool to evaluate the maturity of a regional traffic network structure which describes the traffic convenience in the traffic network. The paper defines a new accessibility index by using the resident population weighted average value of the sum of inverse of the traveling time distance and time threshold coming from ordinary traffic network, and then uses this accessibility index to analyze the spatial-temporal characteristics of Henan highway network, as well as its evolution patterns from 2005 to 2020. The results show that with the expansion and improvement of Henan highway network, city accessibility level has been significantly improved, spatial convergence is obvious, the cities in the north central are always High-High aggregation area, the cities in the south are always Low-Low aggregation area, gradually forming the characteristics of Northwest high and Southeast low, relative balance between East and West. There is some non-conforming phenomenon in highway mileage growth and improvement of the city accessibility levels, but this situation is being weakened, the highway network layout is gradually rationalized, the spatial distribution of city accessibility and that of population are beginning to converge.

基于最优供需分配法的社区公园空间可达性分析——以苏州市姑苏区为例

“城市更新”背景下,社区公园空间可达性研究有助于优化社区公园供需匹配状况,推进高品质社区生活圈建设。针对传统空间可达性测度方法对供需关系识别不够精准的问题,引入最优供需分配法(OSD),以苏州市姑苏区为实证区域,探究社区公园与居民的最优服务配置,根据配置结果确定各居住区居民获取服务所需时间、社区公园服务覆盖率。(1)OSD通过对服务供给与需求的最优分配,能客观呈现社区公园供需匹配的实际情况,对于服务盲区的识别更为精准,所得可达性指标的物理意义明确。(2)最优供需分配结果显示,姑苏区社区公园空间可达性水平整体较低,可达性空间分布较为均衡,高值集中在中南部,低值则在中部片状聚集。(3)空间可达性低值区域,可针对性通过增设社区公园、微绿地、垂直绿化等方式增加服务供给,并完善路网结构,优化可达性水平。研究结果可为社区公园布局规划或调整提供科学依据,为公园绿地可达性研究提供借鉴。

日常的温暖:“为人”的公共空间

后疫情时代背景下,我国城市建设中尤其需要重视“以人为本”的规划设计,实现环境品质的精细化提升。文章针对快速建设中城市公共空间的规划设计重宏大叙事、轻日常使用的现象,通过问题和症结解析,强调公共空间营造需顺应时代发展下的新需求新动向,突出“为人”的初心,成就“日常温暖”的公共场所,并提出了“径、空、用、场”四项关键原则,即“步行力可及、空间好体验、日常多功用、场所有归属”。

县域医疗服务空间公平性评价——以沂南县为例

县域人口密度和医疗服务资源分布不均,不同区位居民采取不同出行方式就医时,产生的出行成本差异较大。为探究基于居民出行特征的县域医疗服务空间公平,文章采用高斯两步移动搜索法计算多出行方式下县域村、乡镇、县级医疗服务空间可达性,采用局部莫兰指数分析可达性集聚特征,进而从空间角度对可达性公平进行评价。案例区分析结果表明:县域医疗服务空间公平与医疗服务质量垂直梯度差异关系密切。县城县级、乡/镇/街道级医疗服务可达性高,强强组合为人口密度较高的县城提供医疗服务,村/社区级医疗服务较为薄弱;近郊区县级医疗服务可达性较高,乡镇医疗服务可达性在各镇交界处较低,村/社区级医疗服务参差不齐;远郊区乡镇卫生院呈补强趋势,镇区周边乡镇医疗服务可达性高,远郊乡镇边缘县级、乡镇级医疗服务可达性低的地区,主要依赖村级医疗服务。研究结果对县域医疗服务公平发展具有理论和实践意义。

基于改进潜能模型的南康家具物流园区空间可达性分析

潜能模型作为测度空间可达性的重要模型,广泛应用于医疗教育、公园绿地等公共设施可达性分析中。以家具物流园为切入点,在物流园区占地面积影响因素的基础上加入物流企业数量因子,构建改进潜能模型测度其空间可达性。同时结合地理信息系统(GIS)插值方法进行可达性等级划分,并在出行时间测算中引入货车限行影响因子。以南康区为例进行家具物流园空间可达性验证分析。结果表明:南康家具物流园区潜能分布较为平衡,中部物流商贸城和红土地物流园作为成熟的物流园其潜能值最大,物流园区空间可达性分布差异不明显,大致呈现出中东部高、周边低的分布格局。

基于空间公平视角的保障房公共服务设施评价——以杭州市蓝领公寓为例

蓝领公寓作为面向低收入外来流动人口的保障性住房,其公共服务设施配套水平直接影响居住人群的生活质量和社会公平正义感知。基于空间公平内涵,从可达性、多样性和适配性3个维度构建面向保障房公共服务设施空间公平的分析框架。以杭州市蓝领公寓为例,结合大数据和小数据(问卷和访谈),运用最小距离、香农—威纳指数、满意度等指标,对配套的医疗、公园、公共交通与便民服务等4类设施进行实证评价。研究结果显示:现有设施综合可达性水平一般,呈现多片区集聚的空间分异格局;设施综合多样性水平中等,单类设施多样性水平差异显著;设施供需适配性较好,但蓝领公寓居民对配套公共服务设施已体现出差异化需求。基于此,从改善设施综合可达性、提升设施多样性和促进设施供需适配性等方面提出对策建议,以期推动蓝领公寓公共服务设施更加均衡公平发展。

基于可靠性分析的避震疏散通道通达性评价

城市避震疏散通道的震后通达性直接关系到能否在第一时间安全转移受灾群众及顺利开展救灾工作。以济南市杆石桥街道为研究对象,考虑到震中沿街建筑的倒塌影响,借助空间句法进行道路系统的抗震可靠性和通达性评价,并提出优化建议。经分析,杆石桥街道建筑密度较高,高层建筑多布局于道路交叉口,均对街区道路的避震疏散功能有一定威胁,且老城区本身避震疏散网络规划不足、存在较多救灾“死角”。随着城市的发展和更新,大多中心城区的规划年代久远,原有避震疏散网络已不能满足需求,近年来自然灾害频发,中心城区的避震疏散通道亟待进行整体评价及优化。