为提高雾天行车安全性,以智慧高速主线为研究对象,分析混行下能见度降低造成安全速度下降、智能网联车(CAVs)驾驶模式降级和换道动机趋于保守的驾驶行为变化情况,建立含纵向跟驰和横向换道规则雾天单向高速公路元胞自动机模型(CAM),通过仿真对模型予以校验,并分析交通流特性和事故概率。结果表明:轻雾、中雾、重雾和浓雾时,车辆降级占比为52.3%、60%、63%和67.3%,2 h换道次数为161、131、104.3和69(×10² veh),自由流最大速度为90、76.8、62.6、46.8 km/h,临界密度为42、40、38、36 veh/km,且随渗透率变小愈加明显;事故概率随渗透率变大而大幅减少,渗透率达到50%以上时,事故概率较人工车辆(HVs)下降不低于52.9%。

In order to improve driving safety in foggy weather, with a section of smart freeway as a research object, changes in driving behaviors under mixed traffic flow were analyzed, including decrease of safe speed, degradation of CAVs driving mode, and conservative lane-changing due to decrease in visibility. Then, a CAM of one-way freeway was established, where rules of longitudinal car-following and lateral lane-changing were designed. Finally, the model was validated through simulation, and traffic flow characteristics and accident probabilities were analyzed. The results indicate that under light fog, medium fog, heavy fog and dense fog conditions, the degradation ratios of CAVs are 52.3%, 60%, 63%, and 67.3%, lane-changing times during two hours are 161, 131, 104.3 and 69 (×102 veh), maximum free flow velocity is 90, 76.8, 62.6 and 46.8 km/h, and critical density is 42, 40, 38 and 36 veh/km, respectively, and they become more and more obvious with the decrease of permeability. Moreover, accident probability decreases greatly with increase of permeability, and it reduces by at least 52.9% when penetration reaches 50% compared to HVs environment.

青藏高原的特殊性长期约束着交通设施的建设与功能,科学评价其交通状况具有重要意义。论文以林芝市为例,考虑自然特征、多种交通方式及交通稳定性,构建综合交通优势度评价体系进行实证探讨。研究发现：① 综合交通优势度以巴宜区、米林县、工布江达县得分较高,其中中心乡镇尤其明显,分别在内部交通功能、对外交通功能、区位优势度方面具有优势,察隅县、墨脱县综合交通优势度及各分项得分均较低,G318、林拉公路、米林机场等重点交通设施影响突出;② 林芝市综合交通优势度的县域差距及空间极化效应趋于增强,但中心—外围结构的空间完整性被地形等因素隔离破坏,边境地区成为林芝市综合交通优势度最为薄弱的环节;③ 综合交通优势度与人口分布具有一定匹配性,多数乡镇二者之间呈协调水平,但以初、中级协调为主,边境和自然条件约束明显的地区尚需考虑优化。根据林芝市特点,改进后的综合交通优势度评价更好地揭示了区域交通薄弱地区,对青藏高原或其他类似特殊地域单元的交通设施评价具有参考意义。

The unique natural environment of the Qinghai-Tibet Plateau has restricted the construction and function of its transportation infrastructure. In order to evaluate the traffic facilities on the Qinghai-Tibet Plateau, taking Linzhi City, a typical area of southeastern Tibet with high altitude and uneven terrain, as an example and considering the natural characteristics, various transport modes, transport stability, and location advantage, this study established an evaluation system of comprehensive traffic advantage degree to empirically examine the situation in 2015 and 2020. The results show that: 1) Bayi District, Milin County, and Gongbujiangda County, especially their central towns, have much higher scores in internal traffic function, external traffic function, and location advantage degree, while the values of traffic advantage and many of its indicators in Chayu County and Motuo County are low, and the impact of some key transportation infrastructures such as the G318 Highway (national highway), Linzhi-Lhasa Highway, and Milin Airport is prominent. 2) The results of spatial difference analysis show that the comprehensive traffic advantage degree of Linzhi City is unbalanced, and the county-level gap and spatial polarization effect tend to increase. However, the core-periphery spatial structure is fragmented and interrupted by terrain factors of extreme difference in altitude, and the border area of Linzhi City becomes the weakest part with regard to the comprehensive traffic advantage degree. 3) There is a certain degree of matching between the comprehensive traffic advantage degree and the population distribution as shown by the linear trend line and coupling coordination relationship. Bayi District, Milin Town, and Gongbujiangda Town have reached the high-quality coordination level. However, most of the towns are at the preliminary or intermediate coordination level, while in the border area and areas with severe natural constraints, the coordination degree urgently needs to be optimized. Methodologically, by superimposing regional natural attributes, expanding the evaluation dimension of traffic advantage degree, and integrating various modes of transportation, the comprehensive traffic advantage evaluation conforms to the actual situation of the study area. Regional transport evaluation that incorporates the consideration of natural environment characteristics has practical significance for supporting territorial planning and transportation infrastructure evaluation and management, especially for regions such as the Qinghai-Tibet Plateau.

Increased lifespans and population growth have resulted in an older U.S. society that must reckon with the complex oral health needs that arise as adults age. Understanding accessibility to screening and treatment facilities for older adults is necessary in order to provide them with preventive and restorative services. This study uses an agent-based model to examine the accessibility of screening and treatment facilities via transportation networks for older adults living in the neighborhoods of northern Manhattan, New York City. Older adults are simulated as socioeconomically distinct agents who move along a GIS-based transportation network using transportation modes that mediate their access to screening and treatment facilities. This simulation model includes four types of mobile agents as a simplifying assumption: walk, by car, by bus, or by van (i.e., a form of transportation assistance for older adults). These mobile agents follow particular routes: older adults who travel by car, bus, and van follow street roads, whereas pedestrians follow walkways. The model enables the user to focus on one neighborhood at a time for analysis. The spatial dimension of an older adult's accessibility to screening and treatment facilities is simulated through the travel costs (indicated by travel time or distance) incurred in the GIS-based model environment, where lower travel costs to screening and treatment facilities imply better access. This model provides a framework for representing health-seeking behavior that is contextualized by a transportation network in a GIS environment.

利用高速公路收费站数据分析东北大都市区的空间边界与中心-外围结构特征。研究发现,① 中心城市高速公路流随距离的分布符合距离衰减规律,随规模位序的累积分布符合“二八定律”,但在具体的指标阈值上却表现出显著差异。② 四大都市区在空间上相连,以较小的国土面积承载了区域主要的社会经济活动。沈阳都市区和大连都市区在城镇关联体系中已实现融合;沈阳都市区、长春都市区、哈尔滨都市区间的空间联系则相对松散。③ 高速公路流空间下,各大都市区中心-外围空间结构表现出空间圈层、功能廊道和边界切割的典型特征。

Spatial boundaries and structural characteristics of metropolitan areas are of great significance for understanding the interactive relationship between cities and regions. Using the data of expressway flows, this paper explored the core-periphery spatial linkages patterns with the indexes of spatial linkages intensity and temporal distance to the central city. On this basis, the spatial boundaries of the metropolitan areas in Northeast China were identified and the characteristics of core-periphery structures were discussed. This article shows that, firstly, the expressway flows of central cities conform to the law of distance attenuation and the Pareto's principle. But the threshold values of different central cities show significant differences, indicating that the agglomerating and radiating effects of the central cities on the surrounding areas have the differences in distance, intensity and direction. Secondly, Shenyang metropolitan area, Changchun metropolitan area, Harbin metropolitan area, and Dalian metropolitan area, where most of the social and economic activities in Northeast China agglomerated, are geographically neighbored. Comparing with Changchun metropolitan area and Harbin metropolitan area, Shenyang metropolitan area and Dalian metropolitan area have a higher density of economic activities and closer spatial linkages, and have integrated as a whole in the urban system network, while the linkages among Shenyang metropolitan area, Changchun metropolitan area and Harbin urban area are relatively loose. Thirdly, under the space of expressway flows, the core-periphery spatial structures of the metropolitan areas show typical characteristics of spatial layers, functional corridors and boundary effect, which have a great impact on the regional economic organization. In future, the development of the metropolitan areas in the Northeast China should focus on solving the restrictive effect of the administrative boundary, promoting the organic combination of the metropolitan areas around Harbin-Dalian axis, and finally forming a regional cooperation system in the form of urban agglomeration or megalopolis.

公共交通是老年人重要的出行方式，到达车站的步行时间是公交服务质量的重要组成部分. 以出发地到车站的步行时间表征车站可达性，基于陈述性偏好调查数据，利用随机系数Logit 模型研究步行时间对老年人公交选择行为的影响. 研究表明：随机系数Logit 模型比传统的多元Logit 模型具有更高的拟合度. 随机系数Logit 模型的效用函数中，车内时间系数为非随机变量，步行时间系数为随机变量；性别、年龄、是否拥有电动车、教育程度、月收入是否大于3 000 元、是否经常使用公交等个人统计学属性，以及老年人对身体状况的主观感知、老年人对体育活动的态度等心理因素，对老年人步行时间价值具有显著影响.

Public transportation is an important way for the elderly to travel, and walking time to the station is an important part of the quality of public transport services. Taking walking time from the origin to the bus station, and based on the stated preference data, this paper analyzed the impact of walking time on the elderly's bus choice behavior with the random parameters Logit model. Through analysis, it was found that the random parameters Logit model fitting the data much better than the multinomial Logit model. The parameter of in-vehicle time was non- random, while the parameter of walking time was random. Furthermore, the elderly's demographic characteristics including gender, age, motorcar ownership, education, monthly income (greater than 3 000 yuan or not), had a significant impact on the parameter of walking time. So did the latent psychological factors, such as psychological factors towards physical activity, perceived physical functioning.

以北京市实时天气数据和基于浮动车的城市道路行程速度、交通运行指数数据为基础，对比分析降雨天气和正常天气的行程速度、指数、降雨量等数据指标.然后从降雨强度、时间段、拥堵等级等角度展开对城市道路运行参数的分析，建立降雨天气速度预测修正模型，并进行模型验证.研究得出，在夜间降雨强度达到中雨及以上时，快速路、主干路、次支路的速度下降百分比分别为：8.8%、4.8%、5.9%，分别得出高峰和平峰时降雨强度与行程速度下降之间的关系；得出在全路网不同拥堵等级下降雨强度与行程速度下降之间的关系.最后对速度预测模型进行实测验证.结果表明，该模型可以对降雨天气条件下的行程速度进行有效预测，预测的平均误差在5%以内.

By utilizing Beijing real-time weather data, travel speed on urban roads and traffic performance index (TPI) based on floating car data (FCD), this paper analyzes and compares travel speed, TPI and rainfalls under rainfall weather and normal weather. Then, the operating parameters of urban roads are analyzed from the perspectives of precipitation intensity, time periods and congestion levels. Further, the correction model for speed prediction is developed and validated. The study shows that travel speeds on the expressway, major arterial and collector decrease by 8.8%, 4.0% and 5.9% respectively when the precipitation intensity reaches the moderate rain level or above at night, and further derives the relationships between the precipitation intensity and the travel speed reduction during the peak and non- peak hours. In addition, the relationships between the precipitation intensity and the travel speed reduction under different congestion levels are also obtained. Finally, application examples are presented to validate the proposed model, which shows that the model can effectively predict the travel speed under the rainfall weather, and the average prediction error is less than 5%.

研究了暴雨对不同车道数的城市快速路交通运行的影响.首先估算了暴雨下自由流车速、通行能力等关键参数下降幅度；然后利用最小二乘法标定了6 种连续型速度—密度模型，最后评价了模型估计关键参数能力和预测车速能力.研究表明：暴雨下路段的自由流车速和通行能力下降幅度、模型估计关键参数能力和预测车速能力都随车道数不同而不同.因此有必要区分暴雨对不同车道数快速路路段的影响.

This paper investigates the impacts of rainstorm condition on traffic operation of multi-lane urban expressways. Firstly, reductions in free- flow speed and capacity are calculated. Secondly, six oneregime speed-density models are calibrated by least square method. Finally, best models for key parameter estimation and for operating speed prediction are assessed. Results show that reductions in free-flow speed and capacity, and the abilities to estimate key parameter and to predict operating speed vary with different number of lanes under rainstorm condition. Therefore, it necessitates distinguishing rainstorm' s impacts on urban expressway segments with different number of lanes.

It is very clear that the transport is one of the most important factors for economic development in the Qinghai Tibet Plateau where the poor transport infrastructure has affected local economic development.In Qinghai Tibet Plateau,high transportation cost and long transport distance of the products has not only limited the competitiveness of local enterprises,but also raised market price of the products from other parts of the country.However,in some areas,there are partly development potentials for some industries due to the superior natural resources and relative favorable transport conditions.In this paper,the relationship between transportation cost and economic development is discussed.The development strategies of comparative advantage and unbalanced development should be properly worked out for local economic development.For example,according to the transportation cost,developing local cement industry is benefit for local economy in Tibet.Some key natural resources,such as salt,chromite,and so on,should be developed as key sectors in some areas.

青藏高原自然环境恶劣,但并非是生命的禁区。确切证据表明,末次冰消期人类已扩张至高原地区,并通过长期实践形成了较为稳定的交通路线格局。通过构建自然因子模拟—遗址分布校正方法,利用GIS得到青藏高原史前交通路线模拟结果,再结合考古证据对模拟路线进行印证。依据模拟结果将高原分为以下4个区：东北区、东南区、西南区以及西北无人区。其中东北区路线遗址点密度高,落入路线内的遗址点数量占总数的88.56%。路线形成于旧石器时期,其方向为东西向,密切联系东北区的内部,并向外沟通黄土高原与北方地区,其形成与发展为彩陶、粟黍、小麦的传播以及丝绸之路的形成奠定了基础。东南区路线为南北走向,北与黄河上游地区连接,南与四川盆地、云贵高原沟通,加强了南北方地区的文化交流,是民族融合与交流的大走廊。西南区位于高原的腹心地带,模拟的路线体现了人类对青藏高原主体的征服,其线路总长度4602.32 km为3个区域内最长,是人类向高原进军的第2条重要通道。西北无人区主要为高寒荒漠区,其自然环境极端恶劣不适宜人类生存,故无路线分布。

青藏高原地区是地球上最独特的地理—生态—人口—交通单元,区域内交通网络的发展特征及规律是人地关系协同发展的一个重要切入点,对青藏高原地区交通网络开展研究具有重要意义。据此,分析1976-2016年青藏高原地区交通网络演化特征,并以省会、地级市、县级市和县城为节点,采用网络分析的时间距离计算模型探讨其通达性演变过程。研究表明：① 青藏高原地区交通网络复杂性、区域连通性增强,初步形成格状交通网络;② 青藏高原地区中心城市、县城之间的平均最短通达时间已极大缩短至11.89 h、18.84 h,呈自东向西逐渐增大的空间格局,时空收敛效应显著,通达性变化程度与其初始值有关;③ 中心城市为该地区的发展极,其与周围城市通达状况有极大提高,可达时间平均值下降到16.49 h;④ 中心城市和县城交通圈演变过程一致,青藏高原地区各地到最近城市、县城的通达时间不断缩小,沿重要交通干线已形成中心城市4 h、县城2 h短时交通圈连片分布格局,湟水河谷地、一江两河地区逐渐形成交通廊道,乡镇对外交通联系得到改善。

The Qinghai-Tibet Plateau is a unique geography-ecology-population-traffic region on the earth. The characteristics and regularities of the transport network development are an important breakthrough for the coordinated development of man-land relationship, which is of great significance to the research in the Qinghai-Tibet Plateau. Accordingly, this paper analyzes the evolution of transport network in this region between 1976 and 2016, and explores its accessibility using a temporal distance calculation model based on network analysis by taking provincial capitals, prefecture-level cities and counties as transport nodes. Results suggest that, first, transport network is more complex and the regional connectivity is gradually enhanced in the plateau, preliminarily forming a grid-like transport network; second, the average minimum accessibility time between anchor cities and between counties has been vastly reduced to 11.89 hours and 18.84 hours, manifesting a gradually growing spatial pattern from east to west and remarkable effects of time-space convergence; third, anchor cities are the poles of regional development, with average accessibility time to around cities reduced to 16.49 hours, indicating that anchor cities tied with others have been improved; fourth, the traffic circles of anchor cities and counties are evolving consistently, accessibility time from various places in the study area to their nearest cities or counties are decreasing, presenting a contiguous pattern of short-time traffic circle with 4-hour access to central cities and 2-hour access to counties along important arterial roads, thus improving external transport connection of towns. And traffic corridors are gradually formed in the Huangshui River Valley, and the Middle Region of "One River and Two Streams" in Tibet.

In this study, we report on the spatial and temporal distribution of seasonal snow depth derived from passive microwave satellite remote-sensing data (e.g. SMMR from 1978 to 1987 and SMM/ I from 1987 to 2006) in China. We first modified the Chang algorithm and then validated it using meteorological observation data, considering the influences from vegetation, wet snow, precipitation, cold desert and frozen ground. Furthermore, the modified algorithm is dynamically adjusted based on the seasonal variation of grain size and snow density. Snow-depth distribution is indirectly validated by MODIS snow-cover products by comparing the snow-extent area from this work. The final snow-depth datasets from 1978 to 2006 show that the interannual snow-depth variation is very significant. The spatial and temporal distribution of snow depth is illustrated and discussed, including the steady snow-cover regions in China and snow-mass trend in these regions. Though the areal extent of seasonal snow cover in the Northern Hemisphere indicates a weak decrease over a long period, there is no clear trend in change of snow-cover area extent in China. However, snow mass over the Qinghai–Tibetan Plateau and northwestern China has increased, while it has weakly decreased in northeastern China. Overall, snow depth in China during the past three decades shows significant interannual variation, with a weak increasing trend.

随着中国区域交通基础设施快速发展,可达性研究受到学界与规划界广泛关注.本文通过梳理近20 年来国内外区域交通基础设施可达性研究的发展脉络,从可达性时空变化及其地域效应方面总结国内外区域交通可达性研究的各自特点与发展方向,判断未来国内相关研究主题.综合比较可知,区域交通可达性的空间格局与时空演变研究仍是国内外交通地理学的研究热点问题.国外研究评价指标丰富,空间分辨率不断提高,分析技术方法日益多样,研究内容更趋于多元化,不断拓宽了可达性研究与应用领域.国内研究发展快,但研究指标体系有待完善,空间分辨率仍有待提高,亟待考虑交通需求与政策干预等现实因素.

With the rapid development of regional transportation infrastructure in our nation, the research on accessibility to transportation infrastructure has been increasingly receiving attentions from academia and scholars in planning field. This article attempts to review the literature of domestic and foreign studies on accessibility to regional transportation in the recent 20 years, summarize characteristics and prospects of the studies from the aspects of temporal-spatial variations of accessibility and the aspects of its regional spatial effect, and predict hot topics of the related domestic research in the future. Through systematically comparing the similarities and differences of domestic and foreign research, we conclude that the research on temporal variations of regional accessibility is still an important topic at home and abroad. As shown in the related foreign literature, there are numerous evaluation indicators; spatial resolutions of accessibility have been continuously improved; more and more analytical technique and methods are being developed. When simulating accessibility, more complex and realistic factors are taken into account, such as traffic congestion, transfer, etc. Foreign research tends to be more diversified, and continues to explore new fields and new applications, such as spillover effect, etc. In the related domestic literature, the research develops quickly and adopts foreign research methods and ideas, but more studies on index system are needed and spatial resolution needs to be further improved. We should also consider more important realistic factors in accessibility research, such as traffic demand and policy intervention etc.

自然资源禀赋差,土地人口承载力低,交通不便,公共服务基础设施差,是贫困山区的基本特征,贫困山区也因此成为人口和产业离心区、生态脆弱区。本文以重庆市酉阳县为例,选取典型村,采用参与式评估、遥感影像和GIS相结合的方法,从微观尺度分析贫困山区农村土地利用演变特征,揭示农村衰落的原因和规律。结果表明:①研究区农村衰落程度严重,植被覆盖率升高,耕地向林草地转变;同时,耕地面积萎缩、聚拢,细碎化程度降低;伴随人口过疏化和老龄化,农村建设用地使用率低,经历由单一到多样,再单一的衰减过程,教育等公共基础服务设施缺位严重;②研究区农村衰落的原因包括农业生计资源匮乏、难以实现农业机械化、聚居分散和城乡比较效益大、农民生活追求的提高以及农业政策实施难度大;③建立以人口流失率、常住人口老龄化率、宅基地萎缩率和耕地变化率4个衰落指标为主的农村衰落诊断方法,诊断表明,研究区农村衰落主要发生在边远山区,距离城镇近、区位优越的农村未表现出衰落。当前农村土地整治和扶贫工作应尊重客观规律,科学制定乡村规划,依靠山区生态系统自我修复、引导人口外迁为主,撂荒耕地择优流转,而复垦未来必然衰落的农村居民点,肯定造成过程性浪费。

Few natural resources,a low population capacity,inconvenient traffic and poor public services are characteristics of poor mountainous areas. These areas are centrifugal areas of population and industry that have fragile ecologies. Focusing on seven typical villages in Youyang County in Chongqing City,we analyzed the micro-scale evolution of rural land use to explore rural decline in poor mountainous areas based on participatory rural appraisal methods and remote sensing imagery interpretation. We found that the degree of rural decline in poor mountainous is severe. Along with rural labor flowing into cities and towns and an increasing number of aging people,rural construction land is inefficient,and the diversity of the rural land use changed from simple to richness to simple again. Cultivated land size became smaller,gathered and less fragmented. Meanwhile,the vegetation rate increased due to conversion between cultivated land and woodland. Many reasons,including a lack of agricultural livelihood resources,difficulty in realizing agricultural mechanization,decentralization and the comparative benefits of urban and rural areas were responsible for the decline in rural mountainous areas. A diagnosis index system of rural decline,including population loss rate,rural residential land shrinking rate and reduction in cultivated area was established. This showed that rural decline mainly occurred in remote mountainous villages. We suggest that rural land consolidation and poverty alleviation should obey the object law,making a rural plan scientific. Self-repair of ecosystems should be emphasized in ecological restoration. Cultivated land should be transferred selectively.

通过构建相应指标体系,采取主成分分析法测度长江中游城市群城市竞争力。在GIS软件支持下,基于时间成本距离栅格的交通可达性分析,利用场强模型,对2015年长江中游城市群31个城市腹地范围进行识别。研究发现：长江中游城市群城市竞争力空间分布差异较大,最大值和最小值相差达5.84倍,与行政级别具有一定关联性。从交通可达性来看,1 h圈空间范围主要集中在中心城市附近,≥3 h圈主要分布在远离省会城市的外围地区,以及岳九咸（岳阳、九江和咸宁）省际交界区。长江中游城市群城市间交通发展缺乏统一规划与协调性,内部交通联系较为薄弱。从空间场强来看,高场强区集中于中心城市及其周边地区,低场强区分布于交通通达性较差的边缘与外围地区,尤其是省际边界地区。场强空间分布与城市竞争力与交通可达性分布具有较强的吻合度,但省际间协同发展程度低。城市腹地范围来看,湖北省大部分城市腹地面积较小,江西省城市腹地面积相对广阔,湖南城市腹地面积居中,三大省会城市腹地面积远超过其他城市,意味着长江中游城市群业已形成以省会城市为多中心的复合型极核发展格局,但内部一体化程度偏弱。从腹地与行政范围的层叠结果来看,城市腹地与市域行政范围吻合度较差,省会城市扩伸率要高于其余城市,而且三大省会城市的域外腹地面积比例远高于其他城市,九江、岳阳、宜昌、常德、新余、景德镇等地域外腹地面积比例也较高。总体来说,长江中游城市群仍停留在子圈内一体化的阶段,还未实现三圈融合和高度一体化发展阶段。

Through the construction of a corresponding index system, the competitiveness of cities in the middle reaches of the Yangtze River in 2015 was measured using principal component analysis, and based on their road traffic layers, the accessibility of cities was measured using GIS grid cost distance spatial analysis technology. Then, the entire spatial field strength was simulated using the field strength model, and the hinterland of the cities was extracted according to the maximum principle. This was done to effectively define the spatial scope of the urban agglomeration in the middle reaches of the Yangtze River. The spatial distribution of urban competitiveness in the middle reaches of the Yangtze River was found to be quite different, and the difference between the maximum and minimum values was 5.84, which is related to the administrative level. In terms of accessibility, the 1-h circle mainly concentrates in the vicinity of the central part of the city, and the 3-h circle and above mainly distributes in the periphery far from the provincial capital city as well as in the Yue-Jiu-Xian provincial boundary area. There is a lack of unified planning and coordination regarding inter-city traffic development in the middle reaches of the Yangtze River, and internal traffic links are relatively weak. Regarding spatial field energy, the high field energy area was concentrated in the central city and its surrounding areas, while the low field energy area was distributed in the marginal and peripheral areas with poor traffic accessibility, particularly in the provincial border areas. The spatial distribution of field strength was in good agreement with the distribution of urban competitiveness and traffic accessibility; However, the degree of inter-provincially coordinated development was low. From the perspective of urban hinterlands, the hinterlands of most cities in Hubei Province are smaller, the hinterland of Jiangxi Province is relatively vast, the hinterland of Hunan City is medium sized, and the hinterland of the three provincial capitals is much larger than those of other cities, which means that the urban agglomeration in the middle reaches of the Yangtze River has formed a complex polar nuclear development pattern with the provincial capital cities as the multi-center However, the degree of internal integration is weak. From the overlapping results of the hinterland and administrative scope, the consistency between the urban hinterland and the municipal administrative scope is poor. Cities with an expansion rate that is greater than 1.1 were mainly Wuhan, Changsha, Nanchang, Yichang, Changde, Pingxiang, Xinyu, Jingdezhen, and Yingtan. Cities with an expansion rate above 0.9 and less than 1.1 mainly included Hengyang, Loudi, and Yueyang. In Xiangyang, Tianmen, and Qianjiang, the expansion rate of other cities was less than 0.9. In addition, the proportion of extraterritorial hinterland of the three major provincial capitals was found to be much higher than that of other cities. The proportion of extraterritorial hinterland of Jiujiang, Yueyang, Yichang, Changde, Xinyu, and Jingdezhen was also higher. Generally, urban agglomeration in the middle reaches of the Yangtze River has stayed consistent at the stage of integration within the sub-circle and has not yet realized integration of the three circles or highly integrated development. This study attempted to identify the spatial range of urban agglomerations by using GIS quantitative analysis technology, and we provide reference for optimization and integration of the urban spatial structure of urban agglomerations in the middle reaches of the Yangtze River.

城市时空大数据技术的快速发展和应用,为城市功能区识别提供了新的数据基础和技术手段,但专门关于城市公共服务设施复合功能的研究还相对较少。基于北京市9大类公共服务设施的空间点数据,综合考虑不同类型公共服务设施等级和品质特征,采用累计机会方法对1 km×1 km格网尺度的北京城市公共服务设施可达性进行了综合评价,在此基础上重点分析了北京城市公共服务设施复合功能特征与影响因素。研究表明：① 北京城市公共服务设施累计机会空间分布存在明显的中心集聚特征,但不同类型公共服务设施的空间分布模式和覆盖范围却有所区别;② 北京城市公共服务设施功能区可以划分为单一功能、单一化的复合功能、2种复合功能、3种复合功能和均衡化的复合功能等5大类型;③ 人口密度、距市中心距离、土地价格和经营性为主设施的累计机会可达性是影响北京城市公共服务设施复合功能的重要因素。研究结论对进一步细化城市功能区研究和促进北京城市公共服务设施空间结构优化具有科学启示作用。