Relationship Between Urban Road Traffic Characteristics and Road Grade Based on a Time Series Clustering Model： A Case Study in Nanjing, China

With the increasing number of vehicles in large-and medium-sized cities challenges in urban traffic management, control, and road planning are being faced. Taxi GPS trajectory data is a novel data source that can be used to study the potential dynamic traffic characteristics of urban roads, and thus identify locations that show a notable lack of road planning. Considering that road traffic characteristics on their own are insufficient for a comprehensive understanding of urban traffic, we develop a road traffic characteristic time series clustering model to analyze the relationship between urban road traffic characteristics and road grade based on existing taxi trajectory data. We select the main urban area of Nanjing as our study area and use the taxi trajectory data of a single month for evaluating our method. The experiments show that the clustering model exhibit good performance and can be successfully used for road traffic characteristic classification. Moreover, we analyze the correlation between traffic characteristics and road grade to identify road segments with planning designs that do not match the actual traffic demands.

Urban Economic Cluster Template and Its Dynamics of Beijing,China

Economic clusters have been a central focus of current urban and regional research, policies and practices. However, a methodology to identify and analyze policy-relevant economic cluster dynamics is still not well developed. Based on input-output(I-O) data of 1987, 1992, 1997, 2002 and 2007 of Beijing, this article presents an adapted principle component analysis for identifying the evolution of local economic cluster patterns. This research addresses the changes of economic interaction of industries with complementary and common activities over time. The identified clusters provide an insight into the reality of economic development in a diversifying urban economy: the increasing importance of services and the growing interaction between service and manufacturing industries. Our method therefore provides the analysts with a better understanding of the emergence, disappearance and development of economic clusters citywide. The results could be used to assist monitoring urban economic development and designing more practical urban economic strategies.

Cluster Development of Zhengzhou Urban Agriculture Based on Diamond Model

Based on basic theory of Diamond Model,this paper analyzes the competitive power of Zhengzhou urban agriculture from production factors,demand conditions,related and supporting industries,business strategies and structure,and horizontal competition.In line with these situations,it introduces that the cluster development is an effective approach to lifting competitive power of Zhengzhou urban agriculture.Finally,it presents following countermeasures and suggestions:optimize spatial distribution for cluster development of urban agriculture;cultivate leading enterprises and optimize organizational form of urban agriculture;energetically develop low-carbon agriculture to create favorable ecological environment for cluster development of urban agriculture.

Design Strategies of Urban Cluster Based on the Concept of Green Transportation

Taking the planning practice of green transportation in Sino-Singapore Tianjin Eco-city as an example,the key factors and design strategies for its healthy development were summarized from the aspects of the coordination of land use and traffic development,the development of the public transport plus slow traffic model,and the development of reasonable and humanized traffic management measures,through analyzing the connotation and scale of green cluster.In addition,the design strategies of the green transportation concept suitable for the development of urban clusters represented by Guangming New District in Shenzhen were proposed,so as to provide a reference for promoting better the coordinated development of green traffic and cities,and maximizing the economic,social and environmental benefits of green transportation development.

Method for Evaluating the Influence of Obstruction of Sea Breeze by Clusters of High-Rise Buildings on the Urban Heat Island Effect

This study aims to propose a method for quantitatively evaluating the influence which the obstruction of sea breezes by clusters of high-rise buildings has on the urban heat island effect using a weather simulation model and Geographic Information Systems (GIS). Specifically, a method of evaluating the influence of the obstruction of sea breeze by high-rise buildings on the urban heat island effect was proposed. In the method, two scenarios that imagine urban forms which differ with regard to whether or not they contain high-rise buildings are created and weather simulation is conducted, and the results of the simulations are comparatively analyzed focusing on temperature and wind speed. Evaluation was conducted in two stages, and Shiodome of Minato City in the Tokyo Metropolis was selected as the region for evaluation. In two stages of evaluation, a rise in temperature of approximately 0.3 K and a reduction in wind speed of approximately 1 m/s were observed in a region approximately five to ten kilometers square downwind of high-rise buildings in the period 6 PM to 9 PM, and a higher temperature caused by the obstruction of sea breeze by high-rise buildings was identified. The fact that such a higher temperature was confirmed in the time period from 6 PM onwards, in which the temperature decreases, reveals that obstruction of sea breeze by high-rise buildings dulls the decrease in temperature which occurs from evening onwards, and influences nighttime urban heat island formation.

Anthropogenic disturbance of aquatic biodiversity and water quality of an urban river in Penang, Malaysia

Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.

城市洪涝风险的多方法组合评估与应用

近年来,受全球气候变化与城镇化快速发展的双重影响,城市极端降水事件频发,由此引发的城市洪涝灾害常造成灾难性的生命和财产损失,给城市公共安全带来了严重威胁。由于不同评估方法中指标赋权不同,评价结果往往存在较大差异,给风险评估与区划工作带来了诸多困难。因此,通过融合不同方法的权重构建一套复合权重,进而解决不同评估方法中结论非一致性的问题,这对于提升风险评估的准确性是至关重要的。该文以湖北省为例,旨从危险性、暴露性、脆弱性和恢复性四个层面构建城市洪涝风险评估体系。首先,分别采用熵权法和层次分析法计算指标权重;之后,通过Kendall检验判断两套权重序列的一致性并给出相应的复合权重计算结果;最后以湖北省下辖8个城市的历史洪涝事件为例,对上述风险评价结果进行了验证。结果显示,与熵权法和层次分析法相比,基于复合权重的组合评价方法具有更高的准确率。

Changing Characteristics of Urban Heat Island Effect in Weihai City

Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal, annual and spatial variation characteristics of urban heat island effect in Weihai City in the past 10 years. The results showed that in recent 10 years, the average urban heat island intensity was 1.24 ℃, showing a gradual weakening trend of -0.169 3 ℃/10 a;the summer average heat island intensity was 0.86 ℃, showing a gradual weakening trend of -0.047 5 ℃/10 a. The heat island intensity had obvious diurnal variation characteristics, that is, "it was weak in the day and strong at night". In terms of seasonal variation, heat island effect was the weakest in summer, stronger in spring and autumn, and the strongest in winter. The diurnal, seasonal and annual changes of heat island intensity showed a reverse trend to those of temperature. The high-value area of urban heat island was highly consistent with human residential activity areas and industrial and commercial intensive areas, and the extension trend of heat island intensity was the same as the direction of urban development and construction. The "cold island phenomenon" in some offshore areas was related to the geographical location, terrain and the southeast monsoon trend in summer. The adverse effects of urban heat island effect can be reduced by optimizing the types and distribution of vegetation communities, rationally planning and constructing urban water body, promoting green building materials and adjusting shape design, etc.

城市群规划实施效果评估研究——以长株潭城市群为例

长株潭城市群经济发展对于湖南省以及中国中西部地区的发展至关重要,且该城市群规划实施的效果对其他城市群有重要借鉴意义。基于此,文章根据2000-2017年地级市面板数据,采用合成控制法,评估长株潭城市群规划实施后对城镇化和环境质量的影响。评估分析表明,长株潭城市群规划的实施推动了城市群城乡融合,在一定程度上促进了城镇化的进程,但对环境造成了一定的负面影响,其原因在于长株潭城市群内城市之间的非均衡发展。因此,城市群应着眼于制定合理规划,促进城市均衡发展,重点落实城乡融合和生态文明;各级政府应加强公共治理,强化监督和治理责任,以更好地实现城市群规划的既定目标。

长三角城市群FDI、技术创新与先进制造业集群发展

FDI和技术创新是长三角城市群先进制造业集群发展的重要影响因素。文章基于2010—2021年长三角城市群26个城市面板数据,分析FDI对先进制造业集群发展的直接作用机制以及技术创新在FDI与先进制造业集群发展之间的中介作用机制,并运用面板回归模型和中介效应模型检验理论假设。研究结果表明:长三角城市群FDI对先进制造业集群发展具有显著的正向作用,其作用机制主要表现为促进集群网络化、产业链优化和劳动力流动;技术创新在FDI与先进制造业集群发展之间具有显著的中介作用。根据研究结论提出长三角城市群促进FDI高质量发展、提高先进制造业集群的科技创新能力、加强FDI与技术创新的协同效应等政策建议。

制造业集聚对城市经济韧性的影响研究

在城市迈向高质量发展的进程中,面对复杂多变的国内外环境,提升城市经济韧性变得越发重要。文章在探究制造业集聚对城市经济韧性影响机理的基础上,运用2008—2021年中国278个城市面板数据进行实证研究。研究发现:制造业集聚可以显著提升城市经济韧性,且这一影响作用具有明显的异质性;有效市场与有为政府的耦合协同效应在制造业集聚提升城市经济韧性的过程中起正向调节作用且具有异质性;空间效应分析表明,制造业集聚对城市经济韧性提升具有正向空间溢出效应。据此,文章针对如何提高城市经济韧性提出相应对策建议。

外卖配送电动自行车换电柜选址定容实证研究

针对外卖配送电动自行车换电柜布局不合理带来的部分换电柜利用率低与部分换电需求得不到及时满足的供需矛盾问题,本文通过聚类POI(Point of Interest)数据确定外卖配送起止点,并通过仿真模拟外卖骑手配送路径预测外卖配送电动自行车换电需求时空分布,构建换电柜运营商总成本最低和用户满意度最高的多目标换电柜选址定容模型,并以新乡市主城区为例,采用NSGA-II(Non-dominated Sorting Genetic Algorithm II)算法得到换电柜选址定容方案。研究结果表明:仿真模拟得出的换电需求时间分布预测值与实际值基本吻合,换电需求在11:00,14:00,17:00和20:00左右急剧增长,且11:00和14:00左右的换电需求量显著高于17:00和20:00左右的换电需求量,外卖骑手配送路径仿真模拟方法在换电需求预测上具有较高的预测精度;换电柜选址方案不能同时满足运营商和用户利益均为最优,用户满意度的提高需以增加运营商总成本为代价;同时,兼顾运营商和用户利益的新乡市主城区外卖配送电动自行车换电柜最佳建设数量为26,其中,容量为11的换电柜11个,容量为22的换电柜8个,容量为33的换电柜7个;新乡市主城区应按照备选点编号15-7-19-17依次新增换电柜至30个,此时,用户满意度最大,若继续增加换电柜建设数量,只会增加运营商总成本。

中国典型城市交通出行特征及未来道路交通演变研究

为建立适合不同城市特点的交通体系,并明确定位汽车在其中承担的作用,文章首先从外部环境和交通工具两大维度出发,建立了表征城市整体交通出行情况的多层级评价体系;并基于一级指标的得分,对选取的9座中国典型城市的交通出行特征进行了聚类分析,确定了城市的不同类型;然后通过多元回归分析,识别了影响城市道路交通的主要因素;最后通过相关因素变化的情景假设,预测了各城市道路交通效率可能的演变情况,并提出了相关政策建议。

城市群集聚规模对城市工资水平的影响研究

城市群是城市发展的高级形态,近年来,随着我国城市发展水平的不断提高,城市群在区域经济中的地位日益突出。为了更好理解城市群的影响,以我国城市群作为研究对象,选取了相关城市2007-2021年的面板数据,对城市群集聚规模影响城市工资水平的方向和路径进行了实证分析。研究结果表明:城市群集聚规模对城市工资水平存在着显著的正向影响,且这种影响是异质的;城市群集聚规模主要通过推动城市产业升级和提升城市创新能力两种途径促进城市工资水平的提高。

宁波都市区森林城市群建设现状、发展指标与总体布局——基于中欧合作研究的城市群森林建设规划

区域是生态环境的共同体,需要协同在城市群尺度推进森林城市群建设。基于对宁波都市区森林城市群建设现状的分析,结合上位规划要求及国内外经验,构建包括7项一级指标(生态资源总量、生态网络、生态保护修复、生物多样性、生态文化、生态福利、区域协同)、24项二级指标的宁波都市区森林城市群建设指标体系;同时,立足宁波都市区现状与发展目标,形成都市区“两山三湾一岛链”,中心区“两屏一区、多廊多点”,生态建设核心区“绿心、绿隔、绿核、绿廊、绿网、绿园”的森林城市群分层布局。研究结果不仅对宁波都市区森林城市群的落地建设具有指导作用,也对我国其他地区森林城市群建设具有重要的参考价值。

影响城市交通发展的基础问题研究

中国城市的发展阶段和趋势特征与社会主义市场经济体制改革的进程息息相关,不同阶段经济社会、城乡建设、法律制度、行政管理、财税制度等各方面的变革都对城市交通发展产生深刻影响。因此,研究新时期城市交通的发展模式必须遵循国家政策和改革措施。通过梳理改革开放以来的变革进程,总结当前中国发展呈现的一系列阶段性新特征,包括社会主要矛盾转变为人民日益增长的美好生活需要和不平衡不充分的发展之间的矛盾,经济体制改革强调推动有效市场和有为政府的更好结合,法律制度规定将城市交通问题的事权和财权划分为地方事务,城市发展进入区域化、数字化、低碳化发展新阶段等。基于这些特征,要求坚持城市政府的主体地位,以改革促进城市交通发展,支撑现代化都市圈培育,面向居民需求提升城市可持续发展能力和竞争力。

黄河流域城市群新型城镇化-生态安全-公共健康协调发展研究

为改善黄河流域生态环境、加强黄河治理保护、促进沿黄地区高质量发展,选取2002-2021年黄河流域7个城市群60个地级市(州)的面板数据,运用熵权法、综合评价模型、耦合协调度模型和BP神经网络模型分析探讨了黄河流域7个城市群的新型城镇化-生态安全-公共健康协调发展状况及其时空演化特征与未来发展趋势。结果表明:①2002-2021年黄河流域城市群新型城镇化、生态安全和公共健康子系统发展水平均有所提升;②新型城镇化-生态安全-公共健康系统耦合协调水平总体上呈现波动增长态势,在整体格局上,位于黄河流域中下游的山东半岛城市群和中原城市群系统发展水平较好,而其他城市群则较差;③预测2022-2026年黄河流域各城市群新型城镇化-生态安全-公共健康系统协调水平将整体显著提升。根据评估与预测结果,提出了相应的对策建议。

新时期阿克苏地区城乡供水安全保障体系探析

本文以阿克苏地区城乡供水安全保障体系为例,在对当地城乡供水现状及存在的问题进行分析的基础上,结合未来发展和新时期供水思路,因地制宜,积极推进城市群供水、城乡一体化供水和集中供水,实施多水源供水和应急备用水源工程,构建与当地经济社会发展相适应的城乡供水安全保障体系,大大提高了供水保障程度。研究成果可为其他地区城乡供水提供一定的参考和借鉴。

京津冀城市群城市韧性的组态效应研究——基于NCA与fsQCA方法的结合

建设韧性城市、提升城市韧性是世界各国发展中关注的重点和焦点。文章基于京津冀城市群14座城市的统计数据,通过文献计量法和熵权-TOPSIS方法构建评价指标体系并进行综合评价,运用NCA与fs QCA结合的方法,探索京津冀城市群城市韧性建设的组态路径。研究发现,城市经济韧性是建设高水平韧性城市的必要条件;城市经济韧性和城市社会韧性是制约高水平韧性城市建设的主要瓶颈;实现京津冀城市群城市韧性建设存在两条路径,分别对应生态型韧性城市和工程型韧性城市。

多源数据融合驱动的城市快速路交通状态划分

为提升交通状态划分效果,本文提出一种基于负激励项的改进模糊C均值聚类(BNITFCM)交通状态划分模型。该模型在原有FCM(Fuzzy C-Means)模型基础上考虑了交通流样本点权重以及交通流参数权重对聚类效果的影响,并引入隶属度负激励项、交通流权重负激励项、交通流样本点权重负激励项使聚类结果呈现类内高耦合、类间低耦合的特性。在此基础上,对样本点进行加权处理,用加权欧氏距离描述样本点之间的关系。通过拉格朗日乘子法得出模型的迭代公式并通过该迭代公式对模型进行求解。针对大多交通状态划分方法参数特征维度低的问题,本文以经过多源数据融合获得的速度、速度标准差、流量、密度和道路满载度构建高维特征输入。以数值仿真实验检验了BNIT-FCM模型在分类准确性方面的表现,结果表明,BNIT-FCM模型较FCM模型和改进模糊隶属度FCM模型(IFMD-FCM)的ARI(Adjusted Rand Index)分别提升了4.17%和3.56%。以深圳市北环大道卡口和浮动车数据的交通流为研究对象,实验结果表明,BNIT-FCM模型对比FCM模型以及IFMD-FCM模型的轮廓系数分别提升了4.12%和4.07%;同时,BNIT-FCM模型采用多源融合数据的速度及其标准差比单独采用卡口数据和单独采用浮动车数据的速度及其标准差的轮廓系数分别提升了29.67%和54.13%。