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.

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.

我国产前诊断机构空间可及性与公平性

目的评价我国产前诊断机构的空间可及性与公平性,以期为优化此类机构的空间规划布局提供参考。方法用两步移动搜索法和空间基尼系数对我国产前诊断机构的空间可及性和公平性进行评价。结果我国中东部地区和各省(自治区、直辖市)中心城市产前诊断服务的空间可及性与公平性均优于西部地区和偏远地区。结论建议适当增加西部地区和偏远地区的产前诊断机构与卫生技术人员数量,以优化我国产前诊断机构的规划布局。

Limited feedback SDMA schemes based on statistical CSI

This paper investigates the multi-beam selection algorithms for transmit correlation channels by using statistical channel state information （SCSI） and instantaneous channel state information. Unlike the conventional codebook-based transmission scheme, the proposed multi-beam selection with the single channel quality indicator （CQI） feedback （MBS- SCF） algorithm determines the preferred beam vector by exploiting the SCSI and only feeds back CQI at each timeslot. The performance of the MBS-SCF algorithm is nearly the same as that of the conventional scheme. In order to further improve the average sum rate, a novel multi-beam selection with the dual CQIs feedback （MBS-DCF） algorithm is proposed, which determines dual preferred statistical eigen- directions and feeds back dual CQIs at each timeslot. The theoretical analysis and simulation results demonstrate that the MBS-DCF algorithm can increase the multiuser diversity and multiplexing gain and exhibits a higher average sum rate.

Modelling geographic accessibility to Primary Health Care Facilities:combining open data and geospatial analysis

Ensuring healthy lives and promoting well-being for all ages is the 3rd Sustainable Development Goal(SDG).Inequality in access to health care remains one of the primary challenges in achieving the goal.With the ever-increasing expansion of urban areas and population growth,there is a need to regularly examine the pattern of accessibility of basic amenities across regions,States and urban areas.This study examined geographic access to Primary Health Care Facilities(PHCF)in Nigeria using the combination of open data and geospatial analysis techniques.Thus,showcasing an approach can be replicated across different regions in Sub-Saharan Africa due to issues of information gap.Data on elevation,location of health care facilities,population and network data were utilised.The result shows that PHCF aggregate at certain locations,e.g.major urban agglomerations,and transit route leading to these places.High concentrations are found in the capital city.The average travel time to the nearest PHCF is about 14 min(Standard Deviation±13.30 min)while the maximum is about 2 hours.Pockets of low accessibility areas exist across the Akwa Ibom State in the Niger Delta region of Nigeria.There is an indication that most places have good geographic access.Across the 1787 settlements identified in our dataset,98.3%are with good access(<30 min),27 settlements are located in the poor access class(31–60 min),while two settlements are within the very poor access class(>60 min).Geographic access is not the main limiting factor to health care access in the region.Therefore,computation of access to health care should take into consideration other dimensions of accessibility,to create a robust measure which will support effective and efficient health care planning and delivery.

A tour-based analysis of travel mode choice accounting for regional transit service

The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area.With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington-Baltimore Household Travel Survey in 2007,including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors.This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.

Quantitative Geography Analysis on Spatial Structure of A-grade Tourist Attractions in China

Tourist attraction is a very important carrier of tourism activities. A-grade tourist attraction is a national standard of comprehensive evaluation about tourist attractions quality and grade in China. In this paper, spatial structure of 2424 national A-grade tourist attractions are investigated by using GIS and quantitative analysis methods, such as nearest neighbor index （NNI）, quadrat analysis, Gini coefifcient and hot spot clustering. Spatial accessibility of all A-grade tourist attractions was calculated using cost weighted distance method and ArcGIS software. Service range of each tourist attraction at 4A grade and above in China was delimitated based on the cost allocation method. Results show that China’s A-grade tourist attractions present aggregate distribution characteristics on the whole, and cultural attractions aggregate distribution is higher than of natural tourist attractions. Above-4A grade quality attractions aggregate distribution is lower than the Below-4A grade tourist attractions; cultural Above-4A grade are signiifcantly greater than the cultural Below-4A grade tourist attractions. A-grade tourist attractions in China’s eight districts are aggregate. The spatial distribution uniformity is low. Affected by the degree of economic development and tourism resources endowment, the service range of Above-4A grade attractions is big in West, smal in East, big in North, and smal in South. First-order hot spots areas were mainly concentrated in the east side of the line formed by Deqen-Alxa Left Banner. The second-order hot spot areas were composed of 11 regions, while the third-order hot spot areas include Beijing, Tianjin, Central Plains and the Yangtze River Delta.

The study on county accessibility in China： Characteristics and effects on population agglomeration

This paper calculated spatial accessibility of all counties （city,urban district） in China with cost weighted distance method. Region divisions of county accessibility were conducted,and relation of traffic accessibility and population aggregation was discussed in this paper. The results indicated that county accessibility in China had mainly low values and a distribution structure of circle layer and reverse-to-natural gradient. There was an obvious correlation between county accessibility and population density in China. With these analyses,inner mechanisms of population migration in different traffic conditions and region types were revealed,and can provide useful proposals to regional planning,traffic planning and smart distribution of people in China.

Understanding coupled coordination relationships between social and ecological functions of urban green spaces

Urban Green Spaces(UGSs)can provide social and ecological benefits,and the coordination of these two functions will largely advance human-nature harmony in cities.As such,we proposed a comprehensive framework to evaluate UGSs multifunctionality,i.e.the coupling coordination relationship of ecological connectivity and spatial accessibility of UGSs.Wuhan City in Central China was taken as a case study,and multiple ecosystem service values of green space patches and the disordered use of UGSs multifunctionality were explored.The results demonstrated low-level coupling coordination of UGSs multifunctionality in Wuhan.More than 70%of UGSs were imbalanced,27.91%of which featured small sizes,low connectivity and accessibility.We suggest that planners should optimize UGSs arrangement to improve species reachability,especially for species with dispersal distance less than 4 km,and to create 15-minute community life circles for residents at the same time.Our findings are expected to support the promotion of UGSs multifunctionality and the balance of urban development and habitat conservation.

分级诊疗制度下的医疗设施可达性研究——以深圳市为例

At present,the hierarchical medical system is widely promoted in China,and the reasonable allocation of medical resources and equal medical services have become important research topics in the field of urban planning.However,it is rare to see studies on the allocation of medical resources from the perspective of spatial accessibility based on the hierarchy of medical facilities and more refined spatial units of population.This research refines the population data from general to residential buildings in urban villages based on census data of buildings.By examining Shenzhen through a 2SFCA(2-step floating catchment area),this research evaluates the accessibility of community and regional medical facilities and the spatial matching at various referral rates by implementing GIS network analysis.The main findings are as follows.(1)The overall development of medical facilities in Shenzhen is currently lagged back among the first-tier cities in China,and there is a discrepancy between administrative districts in terms of the accessibility of medical facilities.(2)Under the current conditions in Shenzhen,the best spatial matching can be achieved only at the referral rate of 70%–80%,indicating weak primary medical resources in Shenzhen.In the future layout and construction of medical facilities,it is necessary to classify and grade the communities and increase the construction of medical facilities in communities with lagging medical standards.In addition,the treatment capacity of community medical services should be improved and the treatment of minor diseases in senior hospitals should be evacuated,so that the referral rate can be controlled at an appropriate level to achieve a balanced allocation and efficient use of medical resources.

Measuring COVID-19 vaccination coverage: an enhanced age-adjusted two-step foating catchment area model

Background:There are only limited studies on access to COVID-19 vaccines and identifying the most appropriate health centres for performing vaccination in metropolitan areas.This study aimed to measure potential spatial access to COVID-19 vaccination centres in Mashhad,the second-most populous city in Iran.Methods:The 2021 age structure of the urban census tracts was integrated into the enhanced two-step foating catchment area model to improve accuracy.The model was developed based on three diferent access scenarios:only public hospitals,only public healthcare centres and both(either hospitals or healthcare centres)as potential vaccination facilities.The weighted decision-matrix and analytic hierarchy process,based on four criteria(i.e.service area,accessibility index,capacity of vaccination centres and distance to main roads),were used to choose potential vaccination centres looking for the highest suitability for residents.Global Moran’s index(GMI)was used to measure the spatial autocorrelation of the accessibility index in diferent scenarios and the proposed model.Results:There were 26 public hospitals and 271 public healthcare centres in the study area.Although the exclusive use of public healthcare centres for vaccination can provide the highest accessibility in the eastern and north-eastern parts of the study area,our fndings indicate that including both public hospitals and public healthcare centres provide high accessibility to vaccination in central urban part.Therefore,a combination of public hospitals and public healthcare centres is recommended for efcient vaccination coverage.The value of GMI for the proposed model(accessibility to selected vaccination centres)was calculated as 0.53(Z=162.42,P<0.01).Both GMI and Z-score values decreased in the proposed model,suggesting an enhancement in accessibility to COVID-19 vaccination services.Conclusions:The periphery and poor areas of the city had the least access to COVID-19 vaccination centres.Measuring spatial access to COVID-19 vaccination centres can provide valuable insights for urban public health decisionmakers.Our model,coupled with geographical information systems,provides more efcient vaccination coverage by identifying the most suitable healthcare centres,which is of special importance when only few centres are available.

Downlink scheduling of multiuser MIMO systems with transmit beamforming

This article deals with downlink scheduling for multiuser multiple-input multiple-output （MIMO） systems, where the base station communicates with multiple users simultaneously through transmit beamforming. Most of the existing transmission schemes for multiuser MIMO systems focus on optimizing sum rate performance of the system. The individual quality of service （QoS） requirements （such as packet delay and minimum transmission rate for the data traffic） are rarely considered. In this article, a novel scheduling strategy is proposed, where we try to optimize the global system performance under individual QoS constraints. By performing scheduling into two steps, namely successive user selection and power allocation, the scheduler can achieve efficient resource utilization while maintaining the QoS requirements of all users. Extensive simulations and analysis are given to show the effectiveness of the proposed scheduler.

A Dedicated MAC Protocol Package for Real-Time Ocean Current Field Estimation Using Distributed Underwater Acoustic Sensor Networks

Distributed underwater acoustic sensor networks(UASNs)are envisioned in real-time ocean current velocity estimation.However,UASNs at present are still dominated by post-processing partially due to the complexity of on-line detection for travel times and lack of dedicated medium access control(MAC)protocols.In this study,we propose a dedicated MAC protocol package for real-time ocean current velocity estimation using distributed UASNs.First,we introduce the process and requirements of ocean current velocity estimation.Then,we present a series of spatial reuse time division multiple access(TDMA)protocols for each phase of real-time ocean current field estimation using distributed UASNs,followed by numerical analysis.We divide UASNs into two categories according to their computing ability:feature-complete and feature-incomplete systems.The feature-complete systems that have abundant computing ability carry out the presented MAC protocol package in three phases,whereas the feature-incomplete ones do not have enough computing ability and the presented MAC protocol package is reduced to two phases plus an additional downloading phase.Numerical analysis shows that feature-complete systems using mini-slot TDMA have the best real-time performance,in comparison with feature-incomplete systems and other feature-complete counterparts.Feature-incomplete systems are more energy-saving than feature-complete ones,owing to the absence of in-network data exchange.