This paper points out that the urban region studied by urban geography has three types. Urban regional system is a synthesis that is composed of geography factors forming the urban region. And it is an organic entirety with different function in the region and complicated structure that is formed by the promotion of productivity and urbanization. The system is an urban function regional one formed by the differentiation and combination of urban region. And the urban regional system is developing, changing, differentiating and integrating all the time. The reasonable urban regional system must have the comparable and functional feature, and the urban statistic must be true. The foreign geographers have studied the foundation of urban regional system for a long period of time. This paper analyses the American Standard Metropolitan Area (SMA) Theory and the Japanese Densely Inhabited District (DID) Theory that are representative and ripe. All these theories can be used by China to reconstruct the urban regional system for reference at the aspect of theory and method. Comparing with foreign study, China has attempted for many times at the aspect of foundation of urban regional system. But some problems of concepts and methods still exist. After the analysis of theory and method about the construction of the pertinent urban region system at home and abroad, the paper points out the subsistent problems in the define of urban region system in China. On the base of analysis of necessity of reconstruction of Chinese urban regional system, this paper puts forward the idea of reconstruction based on daily life circle and defines the concept of daily life circle. From the point of view of inhabitant's individual life, daily life circle is the spatial area that the daily activities of urban inhabitant involves such as inhabitation, work, education, shopping, medical treatment, entertainment and commuting. The daily life circle is a material urbanization region of a city, and it is the spatial shape and structure system that is formed through urban inhabitant fulfills all kinds of activities in the material urban regional system. It is a functional urban regional system including three circles-essential life circle, basic life circle and opportunity life circle. The essential life circle corresponds to the built-up area of city. The basic life circle corresponds to the linking part of town and country. The opportunity life circle corresponds to outskirts of city. The reconstruction uses the method of raster technique. This method realizes that basic spatial unit of urban regional system based on daily life circle can't be confined by the urban district borderline, and can describe the urban developing level objectively. In the last part, the paper discusses the feasibility of construction of Chinese urban regional system based on daily life circle elementarily. The idea of daily life circle can be used to study Chinese urban developing rules from the point of microcosmic view. And it can also provide a new thinking method to frame and accomplish urban planning and management. The idea of daily life circle has important theoretical and practical meaning for the theoretical study and the practice of urban planning for Chinese urban problems.

Community life circle examines urban communities from the perspective of residents' daily activities. It is the frontier of urban geography and urban related studies. It is also an important part of the innovation of Chinese territorial and spatial planning system and an important starting point for the sustainable development of China's urban society. With the continuous deepening of mobility and informatization, the agents of community life circles, community activities and residents' spatiotemporal behavior, and the function and meanings of community space are becoming more diversified, which needs innovative research and practical guidance of urban social geography. Time-geography is a comprehensive social-technical-ecological approach to understand the relationship between humans and the environment, which provides an essential basis for early research on community life circles based on activity space. New time-geography attaches great importance to the interactions and spatiotemporal combinations of projects between family and other social organizations. It can provide an important basis for the study of the complex interactions between individual, family, and community and the sociocultural constraints, the complex context analysis, and the simulation of spatiotemporal behavior in community life circles. Based on the new time-geography approach, this study proposed a new time-geography research framework of community life circle from theoretical, methodological, and empirical perspectives, including: 1) constructing the community life circle theory based on spatiotemporal behavior and revealing community life circle spatial and temporal structures; 2) developing methods for collecting and analyzing spatiotemporal behavioral data of community life circle and simulation; 3) innovating Chinese urban planning and management from the aspects of optimizing residents spatiotemporal behaviors within the community life circle, community social interaction life circle, and community safety life circle.

社区生活圈从居民日常活动及行为视角考察城市社区,是城市地理学和城市相关学科的研究前沿,也是中国国土空间规划体系创新的重要组成部分,以及中国城市社会可持续发展的重要抓手。伴随着流动性和信息化的不断深入,社区生活圈的主体日益多元化、社区活动和居民时空行为日益多样化、社区空间的功能与意义日益丰富化,亟需城市地理学的研究创新与实践引导。时间地理学是理解人与环境关系的社会—技术—生态综合方法,为早期基于时空行为与生活空间的社区生活圈研究提供了重要基础。新时间地理学重视家庭及其他组织企划的交互与时空组合,可为社区生活圈内个体—家庭—社区之间的复杂互动关系研究、时空行为的社会文化制约与多情境分析及模拟提供重要支撑。论文基于新时间地理学方法,从理论、方法和实证3个维度提出社区生活圈的新时间地理学研究框架,具体包括构建社区生活圈的时空行为理论,揭示社区生活圈的时空间结构;创新社区生活圈的时空行为分析和模拟方法;从社区生活圈时空行为优化、社区交往生活圈、社区安全生活圈等方面创新中国城市规划与管理等研究内容。

The level of urban public service provision directly affects the life quality of residents, and location and allocation of urban public service facilities are an important task of urban planning and development. In recent years, the concept of urban life circle has been paid increasing attention to in China, and various localities have aimed to create a perfect "community life circle" as a key task of urban governance. Using the open source map data and the urban network analysis (UNA) toolbox, this study analyzed the spatial difference of public service facilities in Shahekou District of Dalian City, and measured the number and type of reachable facilities to residents of 90 communities in the district. Then, an overall evaluation of each community was conducted. Finally, the optimal allocation of public service facilities was proposed. The results show that: 1) Public service facilities are unevenly distributed in Shahekou District of Dalian City. There are more facilities on the north side and fewer on the south side, showing a structure of one primary center and six secondary centers. The primary center is around the commercial area of Xi'an Road and the secondary centers are distributed in each subdistrict. 2) There is a large difference in the number of reachable facilities to residents—facilities on the north side of the Malan River are more than that of the south side, and there are more facilities in one or two areas in each subdistrict. 3) There are some differences in types of reachable facilities to residents, and more than 70% of the residents can reach all six types of public service facilities. The number of facility types reachable to residents on the west side of Xibei Road-Xinan Road-Wuyi Road is less than that of the east side. 4) Generally, in various communities reachable facilities are balanced and have small differences. However, there are still some communities that show large internal differences. According to the analysis, whether residents can access the various public service facilities is greatly affected by the distribution of facilities, the barriers of ground objects, and the closed degree of community. At the end of this article, we propose to build 15-minute community life circles with all needed facilities and easy to reach.

城市公共服务设施的配置水平直接影响到居民的生活品质。论文基于高德地图获取的地图数据,使用城市网络分析工具(Urban Network Analysis Toolbox, UNA)对大连市沙河口区内的6类公共服务设施分布进行空间分异分析,并对区内90个社区的居民出行可达设施的数量及类别进行测度,最后对各个社区进行总体评价。结果表明：① 大连市沙河口区公共服务设施空间分布不均,北多南少,呈现出“一主多次”的“廾”字形的结构,主要分布在西安路商业区周边和各个街道的次级商业区;② 居民可达设施数量空间差异大,北多南少,各街道均有1或2个区域可达设施数量较多;③ 居民可达设施类型数量存在一定差异,70%以上的住宅楼中的居民可以获得全部6类公共服务设施;④ 各社区居民可达设施总体处于差异较小的均衡状态,但仍有个别社区存在内部差异较大的现象。设施的分布、地物的阻隔和社区的封闭程度对居民获取各类公共服务设施影响较大,建议构建“设施完善、便捷可达”的15 min社区生活圈。

The 15-minute community life circle (15min-CLC) strategy is one of Shanghai’s important methods for building a global city and facing a society with a more diverse population structure in the future. In the existing research, the balance between the construction of the life circle and the needs of the people in the life circle still needs to be further fulfilled. This paper is based on the city’s multi-source large data set including 2018 AutoNavi POI (Point of Interests), OSM (OpenStreetMap) road network data and LandScan population data set, and evaluates the current status of Shanghai’s 15min-CLC through the fusion of kernel density estimation, service area analysis and other statistical models and proposes relevant optimization suggestions. The results show that there are the following shortcomings: (1) From the perspective of different types of infrastructure service facilities, the spatial construction of Shanghai’s overall life service facilities and shopping service facilities needs to be optimized. (2) From the perspective of comprehensive evaluation, the comprehensive service convenience of infrastructure service facilities in the downtown area is relatively high, while the comprehensive service convenience of urban infrastructure service facilities in the suburbs and outer suburbs is relatively low; The diversity of basic service facilities in the 15min-CLC in the downtown area is more consistent with the population distribution; However, in the peripheral areas of the urban area, too many infrastructure service facilities have been constructed. Based on the above shortcomings and the perspective of supply and demand matching, relevant optimization strategies are proposed in different regions and different types of infrastructure service facilities: (1) focus on the construction of basic service facilities in the urban fringe and urban-rural areas, improve the full coverage of the basic service facilities, and appropriately reduce the number of basic service facilities in the downtown area. (2) The development of community business models can be used to promote the development of new life service facilities and shopping service facilities. (3) Improve community medical institutions through facility function conversion, merger and reconstruction, etc. (4) Optimize the hierarchical basic service facility system and improve the population supporting facilities of basic service facilities in the 15min-CLC. This paper incorporates people’s needs and concerns on the living environment into the 15min-CLC evaluation model, and uses Shanghai as an example to conduct research, summarizes the existing shortcomings, and proposes corresponding optimization strategies based on the matching of supply and demand. This article attempts to explore a replicable 15min-CLC planning model, so that it can be extended to the Yangtze River Delta urban agglomeration, to provide reference for further research on the 15min-CLC, and to promote urban construction under the concept of sustainable development.

Public service facilities (PSF) are the basic guarantee for urban production and living. Whether the distribution of public service facilities is equitable is related to the healthy development of cities and the society. At present, due to the lack of urban micro-scale population distribution data, there are few studies that consider both the supply side (PSF) and the demand side (population). In view of this, using the Internet maps application programming interface (API), this study established the 5-minute, 10-minute, and 15-minute community life circle of Lanzhou City, and then used Worldpop grid data, population census data, and Baidu heat map data to simulate the population distribution at high spatial resolution and with high accuracy. We evaluated the matching relationships between population and public service facilities in Lanzhou City. The study found that: 1) The matching relationships between different types of PSF and population are very different. However, they show a common phenomenon that the matching degree close to district administrative centers is often better than that of urban fringe. 2) In Lanzhou City, the matching relationships between PSFs and population are highly polarized, that is, there are more highly matched and mismatched life circles, and the number of moderately matched and relatively poorly matched life circles is fewer. 3) Based on the coverage of moderately and highly matched life circles, the coverage of all levels of travel, medical (except community health service centers corresponding to 10-minute life circle), dining, and entertainment facilities is the widest. The allocation of elderly care facilities at all levels and grass-roots cultural facilities is seriously inadequate, and other facilities are between the two types. The study concludes that the problems that have been identified need to be addressed. It suggests that urban planning should focus on the allocation of various PSF in the urban fringe, and improve the coverage of all levels of elderly care facilities.

公共服务设施是城市社会服务最基本的承载体,公共服务设施分配的公平与否,事关城市健康发展和社会公正运行。目前由于城市微观尺度人口数据的缺失,鲜有研究将供给侧(公共服务设施)与需求侧(人口)统一起来。鉴于此,论文以互联网地图API为支撑,建立了5 min、10 min、15 min三个层级的社区生活圈,并模拟了高分辨率、高精度的人口分布图,对案例城市兰州市的公共服务设施与人口的匹配关系进行了详细评估。研究发现： ① 不同类型公共服务设施与人口的匹配关系差异较大,但均表现为区级中心匹配状况较好,城市边缘区域漏配较多;② 兰州市大部分公共服务设施与人口匹配关系两极分化性较强,即高配型与漏配型生活圈数量较多,适配型与低配型生活圈数量相对较少;③ 从中、高匹配度的生活圈的比例来看,各级出行类、就餐类、娱乐类、医疗类设施(10 min生活圈对应的社区卫生服务中心除外)的覆盖范围最广,各级养老类设施和基层文化设施的配置严重不足,其他设施介于两者之间。对于暴露出的问题需要查漏补缺,研究认为,当前公共服务设施规划的重点在于解决养老类设施普及性低和城市边缘区各类公共服务设施配置不足的问题。

The calculational aspects of solving certain classes of location-allocation problems are presented. Both exact extremal equations and a heuristic method are presented for solving these problems. Directions for further investigation are also indicated because of the need for methods to shorten the total amount of calculation involved.

The concepts of the “center” and the “median vertex” of a graph are generalized to the “absolute center” and the “absolute median” of a weighted graph (a graph with weights attached to its vertices as well as to its branches). These results are used to find the optimum location of a “switching center” in a communication network and to locate the best place to build a “police station” in a highway system. It is shown that the optimum location of a switching center is always at a vertex of the communication network while the best location for the police station is not necessarily at an intersection. Procedures for finding these locations are given.

This paper attempts to present the major methods, successful or interesting uses, and computational experience relating to integer or discrete programming problems. Included are descriptions of general algorithms for solving linear programs in integers, as well as some special purpose algorithms for use on highly structured problems. This reflects a belief, on the author's part, that various clever methods of enumeration and other specialized approaches are the most efficacious means existent by which to obtain solutions to practical problems. A serious try at gathering computational experience has been made—but facts are difficult to uncover.

A commonly occurring problem in distribution system design is the optimal location of intermediate distribution facilities between plants and customers. A multi-commodity capacitated single-period version of this problem is formulated as a mixed integer linear program. A solution technique based on Benders Decomposition is developed, implemented, and successfully applied to a real problem for a major food firm with 17 commodity classes, 14 plants, 45 possible distribution center sites, and 121 customer zones. An essentially optimal solution was found and proven with a surprisingly small number of Benders cuts. Some discussion is given concerning why this problem class appears to be so amenable to solution by Benders' method, and also concerning what we feel to be the proper professional use of the present computational technique.

Spatial accessibility is an important index for measuring fairness in public services such as health care, education, and outdoor leisure. It has also been widely used in the layout planning of public facilities. However, the existing accessibility models cannot fully illustrate the direct relationship between service supply and demand, and thus, the accessibility indicators cannot be explained with explicit meanings. This article introduces a new method for measuring accessibility based on optimal supply and demand allocation, which is different from the supply-demand relationships in existing methods. Given the supply locations, the demand locations, their attributes, and the travel costs between them, the transportation problem model is used to allocate services to demands. The classical model can be easily solved with optimal total travel cost. Based on the model results, the spatial accessibility of services can be measured. The proposed method was tested on healthcare services in a district in Zhengzhou, Henan, China. There were 25 healthcare centres and 1333 residential communities in the study area. The instance model was effectively built by an open-source MIP solver in 2.2 seconds. The service area of each healthcare centre and the travel time from each community were obtained according to the modelling results. In addition, the coverage percentages with predefined service thresholds were calculated. The proposed method was also compared with popular methods, such as the two-step floating catchment area method (2SFCA), Gaussian 2SFCA, and gravity 2SFCA. Areas with poor healthcare services were identified by using the results from the three 2SFCA methods. However, the spatial variation in service accessibility might be very different when selecting different search thresholds and/or distance decay coefficients. The optimal supply-demand accessibility method (OSD) proposed in this study has advantages such as being parameter-free, easy to calculate, and easy to explain. The authors believe that the method has application potential to replace the existing methods in evaluating public services and facility planning.

空间可达性是衡量公共服务设施公平性的重要指标,在医疗、教育、休闲等公共服务的布局规划中得到广泛应用。然而已有设施服务可达性模型难以充分反映服务供需关系,计算指标也缺乏物理意义。本文提出新的最优供需分配的公共设施空间可达性计算方法（OSD）取代现有方法。该方法基于最优供需分配模型,将设施服务分配给需求者,根据分配结果计算空间可达性指标。给定服务设施与需求的空间分布,以最小化旅行成本为目标,顾及设施服务能力,采用经典的运输问题模型确定最优的服务供需分配方案,进而度量服务的空间可达性。以郑州市金水区社区卫生服务为例,求解25个中心与1333个居住小区的最优服务配置。使用最优配置结果确定每个设施的服务范围、每个居住小区使用服务的旅行时间,以及特定时间阈值的服务覆盖比率。与流行的两步移动搜索法相比,新方法的计算指标具有明确的物理意义。本文提出的可达性评价方法无需参数,计算高效,结果易于解释,在公共服务评价及设施布局规划方面具有应用潜力。