研究方法

Research method

本研究采用两步移动搜索法，能够考虑供需两点间的承载关系同时兼顾通勤成本因素，因而被较多研究所选用。两步移动搜索计算的可达性包含了两个层面的含义，即空间可达与服务资源可达。然而该计算模型对两个关键参数较为敏感，分别为空间作用域的半径和距离衰减参数，半径的不合理设定和空间作用域内的均质性，会导致计算结果与现实有一定偏差。本研究对两种参数进行了设定，分别为：使用路网距离代替欧氏距离，将实际步行时间下的空间范围作为空间作用域，其阈值范围在两个步骤计算中进行了分别设定。

另外，本研究采用空间自相关分析方法进行设施布局集聚特征研究。空间相关性可以用来探测聚类、离散和随机三种空间数据分布模式。基于ArcGIS软件平台，使用全局莫兰指数和局部莫兰指数两种分析工具，对各小区的可达性数值进行空间聚类。全局莫兰指数计算结果从总体上反映了数值在研究区域的空间自相关性，用于判断整体是否出现空间集聚现象。局部莫兰指数用于判定具体空间上的聚集类型，即呈现高高聚集分布以及低低聚集分布的区域

In this study, the two-step mobile search method is adopted, which can consider the bearing relationship between supply and demand and take into account the commuting cost factor, so it is chosen by many studies. The reachability of two-step mobile search computing contains two meanings, namely, space reachability and service resource reachability. However, the calculation model is sensitive to two key parameters, namely, the radius of the space scope and the distance attenuation parameter, and the unreasonable setting of the radius and the homogeneity of the space scope will lead to a certain deviation between the calculation results and the reality. In this study, two parameters were set, namely, the road network distance was used instead of Euclidean distance, the spatial range under the actual walking time was taken as the spatial scope, and the threshold range was set separately in the two steps of calculation.

In addition, the spatial autocorrelation analysis method is used to study the clustering characteristics of facility layout. Spatial correlation can be used to detect clustering, discrete and random spatial data distribution patterns. Based on ArcGIS software platform, two analysis tools, global Moreland index and local Moreland index, were used to cluster the reachability values of each cell. The results of the global Moreland index reflect the spatial autocorrelation of the values in the study area in general, which is used to judge whether the spatial agglomeration occurs in the whole. The local Moran index is used to determine the type of aggregation in a specific space, that is, the regions with high aggregation distribution and low aggregation distribution

研究成果

Research achievement

如表1所示，在不同研究单元尺度下的养老助餐服务设施可达性（以下简称可达性）数值的统计结果。从统计结果可知，不同研究单元尺度下，可达性数值的平均值和标准差均呈现先增后减趋势。这表明了随着计算时间的增加，老年人配餐设施呈现先增再减的趋势。

As shown in Table 1, the statistical results of the accessibility of assisted meal service facilities for the aged (hereinafter referred to as accessibility) at different research unit scales are obtained. According to the statistical results, the mean and standard deviation of the reachability value increase first and then decrease at different research unit scales. This indicates that with the increase of computing time, the elderly catering facilities show a trend of first increasing and then decreasing.

可达性标准差的总体变化趋势与可达性均值变化较为一致（图2），养老助餐服务可达性的差异性随研究单元尺度增大而显著，这是因为助餐设施以及老年人口分布具有空间分异现象，随着生活圈范围扩大，相应范围内供需关系的变化差异较大。同时从标准差变化斜率来看，在5~25 min的标准差上升较快，在25~35 min之后逐渐趋于平稳，同样在设定为40 min时有拐点出现，之后数值标准差下降。这说明，养老助餐可达性对于5~25 min的研究单元尺度较为敏感。

The overall change trend of the standard deviation of accessibility is consistent with the change of the mean accessibility (FIG. 2). The difference in accessibility of assisted meal services for the elderly is significant with the increase of the size of the research unit, because the distribution of assisted meal facilities and elderly population has spatial differentiation. At the same time, from the perspective of the slope of the change of standard deviation, the standard deviation rises rapidly in 5-25 min and gradually becomes stable after 25-35 min. Similarly, there is an inflection point when it is set at 40 min, and then the numerical standard deviation decreases. This indicates that the accessibility of assisted meals for the elderly is sensitive to the research unit scale of 5 to 25 minutes.

 以上部分对多种研究单元尺度下的助餐现状进行了评价，该章节参照章节4.3中的分类标准，计算各小区欲达分割线仍需补充的设施数量。15 min养老生活圈是当前政府明确提出的基本养老服务平台，据最新上海市发布的政策，要设置15 min服务圈社区嵌入式服务驿站，统筹考虑确定15 min内的服务设施数量。为了与市政府的政策相适应，研究依托15 min阈值下的助餐可达性分布现状，计算推衍各小区欲达各分割线所需养老助餐设施数量。

基于可达性计算公式进行反向逆推，计算各小区达到助餐设施的最小缺失数量。值得说明的是，由于原文中使用了高斯衰减函数进行距离衰减，而本章节计算数量临界值，因此只需考虑服务能力最大化的情况，即计算无距离衰减程度下，至少需要增加的助餐设施场所数量。计算结果的数据统计见表3。

The above part evaluates the current situation of auxiliary feeding at various research unit scales. This chapter calculates the number of facilities that need to be added in each community to reach the dividing line by referring to the classification criteria in Section 4.3. 15 min elderly living circle is the basic elderly care service platform clearly proposed by the current government. According to the latest policy issued by Shanghai, 15 min community embedded service stations should be set up in the service circle, and the number of service facilities within 15 minutes should be determined by overall consideration. In order to adapt to the policy of the municipal government, based on the distribution status of assisted meal accessibility under the 15-min threshold, the study calculated and deduced the number of assisted meal facilities for the elderly in each community to reach each division line.

Based on the reachability calculation formula, the minimum missing number of assisted meal facilities in each community was calculated. It is worth noting that, since the Gaussian attenuation function was used for distance attenuation in the original article, and the quantity critical value was calculated in this chapter, only the case of maximum service capacity was considered, that is, the number of feeding facilities requiring at least an increase without distance attenuation was calculated. The statistical data of the calculation results are shown in Table 3.

社区层级的可达性计算结果显示了与县区和街镇层级所不同的情况。总体来说，全市大部分社区的养老助餐设施可达性较差。原因为即使随着研究单元尺度的扩大，能够被纳入研究单元的设施点十分有限，因此计算结果中大部分小区可达性仍然较差。从分布区域看，在县区边界区域的社区养老助餐设施可达性相对较好，而可达性较差的社区主要集中在中心城区附近。

通过以上三个层级的集计分析结果，研究得出结论如下：首先，当计算结果在不同行政区尺度下进行集计分析时，随着行政单元的扩大，区域内的差异性被抹除；其次，城市中心区域尤其是以浦西7区为代表的区域，可达性的数值相对较低；最后，相对于上海市养老服务专项规划制定的以县区为单元的指导政策，本研究的计算结果，可以用于进行更加详尽细致的区域识别。

The results of accessibility calculation at community level show that the situation is different from that at county level and street level. In general, most communities in the city have poor access to assisted feeding facilities for the elderly. The reason is that even with the expansion of the size of the research unit, the facility points that can be included in the research unit are very limited, so most of the cell reachability in the calculation result is still poor. From the perspective of distribution area, the accessibility of the community elderly meal assistance facilities in the border area of the county is relatively good, while the communities with poor accessibility are mainly concentrated near the central urban area.

Based on the results of the above three levels of aggregate analysis, the research draws the following conclusions: First, when the calculation results are analyzed under different administrative scales, the differences within the region are erased with the expansion of administrative units; Secondly, the accessibility value of urban center area, especially Puxi District 7, is relatively low. Finally, compared with the guidance policy based on county and district in the special plan of Shanghai elderly care service, the calculation results of this study can be used for more detailed and detailed regional identification.

研究结论

Research conclusions

第一，上海市的养老助餐设施可达性分布存在空间分异现象，位于城市边缘地区的小区养老助餐可达性相对较好，而城中心区域可达性数值较差。即使扩大研究单元尺度，仍然有大量小区的助餐设施可达性较差。

第二，经过9种研究单元尺度的对比，我们发现在助餐可达性的评价中，使用40 min的研究单元尺度时间阈值受到干扰程度最小，相对使用15 min生活圈阈值进行评价，40 min的时间阈值更加合适。

第三，虽然目前上海市建设的助餐点数量总体较多，但是生活圈内的有效数量仍然欠缺，根据划定的三条分割线，大部分小区处在助餐可达性标准线以下。经过反向推演计算的各小区15 min生活圈内的设施缺失量，欲达标准线，各小区需要补充助餐设施数量主要在2~14个之间（上下四分位数），最多的需要补充20个养老服务设施，整体来看，各小区需要补充的数量标准差为5.79左右。就分布区域来看，浦西七区的助餐设施缺失较为严重，尤其是靠近黄浦江的东侧区域，其他周边区域各层级分割线下需要补充的数量较少。

第四，随着研究单元尺度的变化，受到干扰程度较小的社区主要集中在城中心区域，但是体现出来的是低水平的稳定和韧性；而受到干扰程度较大的小区主要分布在嘉定区。

第五，助餐可达性在三个行政层级的集计发现，当计算结果在不同行政区尺度下进行集计分析时，随着行政单元的扩大，区域内的差异性被抹除，相对于上海市养老服务专项规划制定的以县区为单元的指导政策，本研究的计算结果，可以进行更加详尽细致的区域识别。

第六，从空间集聚来看，可达性数值呈现高值聚类分布的区域主要集中在嘉定区，呈现低值聚集分布的区域主要在城中心和青浦区等区域。总体方向层面上，西北部好于其他区域，呈现西强东弱的局面；可达性呈现低—低聚集分布的小区主要是集中在上海二环以内的区域，而呈现高—高聚集分布主要集中在以嘉定区为主的区域；徐汇区南部和闵行区交界处的区域，成为低值集聚区域的异常区域，这个区域聚集的上百个小区呈现高值集聚分布；研究单元尺度的扩大，基本不会影响目前的集聚状态。

First, there is spatial differentiation in the accessibility distribution of assisted meals for the elderly in Shanghai. The community located in the urban fringe has relatively good accessibility, while the accessibility value in the urban center is poor. Even with the expansion of the study unit size, there are still a large number of communities with poor accessibility of feeding facilities.

Second, through the comparison of 9 research unit scales, we found that in the evaluation of meal accessibility, the time threshold of 40 min research unit scale was least disturbed, and the time threshold of 40 min was more appropriate than that of 15 min life circle threshold.

Third, although the number of assisted meals built in Shanghai is generally large, the effective number within the living circle is still lacking. According to the three demarcated lines, most of the communities are below the standard line of assisted meals accessibility. According to the amount of facilities missing within the 15-min living circle of each community calculated by reverse deduction, to meet the target line, the number of auxiliary meal facilities needed by each community mainly ranges from 2 to 14 (upper and lower quartiles), and the most needs to supplement 20 elderly care service facilities. On the whole, the standard deviation of the number of supplementary facilities needed by each community is about 5.79. In terms of distribution area, the lack of auxiliary meal facilities in the seven districts of Puxi is more serious, especially in the east area near the Huangpu River, and the number of supplementary items under the division line of various levels in other surrounding areas is small.

Fourth, with the change of the scale of the research unit, the less disturbed communities are mainly concentrated in the central area of the city, but the stability and resilience are at a low level. The most disturbed areas are mainly distributed in Jiading District.

Fifth, based on the aggregate analysis of the accessibility of assisted meals at three administrative levels, it is found that when the calculation results are analyzed at different administrative scales, the differences within the region are erased with the expansion of administrative units. Compared with the county-district guidance policy formulated in the special plan of Shanghai elderly care service, the calculation results of this study can be more detailed and detailed regional identification.

Sixth, from the perspective of spatial agglomeration, the areas with high clustering distribution of accessibility values are mainly concentrated in Jiading District, while the areas with low clustering distribution are mainly in urban center and Qingpu District. On the general direction level, the northwest is better than other regions, showing a situation of strong west and weak east; The low - low clustering distribution of accessibility is mainly concentrated in the area within the Second Ring Road of Shanghai, while the high - high clustering distribution is mainly concentrated in the area of Jiading District. The area at the junction of southern Xuhui District and Minhang District became the abnormal area of low-value cluster area, and hundreds of clusters gathered in this area showed high-value cluster distribution; The expansion of research unit size will not affect the current agglomeration status.