中国城市群区域城际轨道交通布局模式

我国城市密集区与城市群的迅速发展,对交通网络化、现代化的需求日益迫切,而城际轨道交通是城市群发展的重要条件和前提。国外发达国家发展的经验表明,城际轨道交通是城市群客流运输最佳的交通方式选择,两者相互影响、互为促进,城市群区域和城际轨道交通之间的空间结构存在着必然的空间映射关系。基于此,本文根据我国城市群发展现状及其区域空间结构发展的5种模式,相应提出放射型、钟摆型、串珠型和网络型等4种城际轨道交通布局形式,并阐述各自特点。在未来一定时期,国内城际轨道交通将蓬勃发展,必须根据城市群区域空间结构发展模式,进行科学规划和布局形式的选择,以有效满足日益庞大的客流需求和推动城市群发展战略的实现。     

Water age in stormwater management ponds and stormwater management pond-treated catchments

Expansion of impervious surface cover results in “flashy” hydrologic response, elevated flood risk, and degraded water quality in urban watersheds. Stormwater management ponds (SWMPs) are often engineered into stream networks to mitigate these issues. A clearer understanding of how water is stored and released from SWMPs and SWMP-treated catchments is required to better represent these engineered systems in hydrological and water quality models of urban and urbanizing watersheds. Stable water isotopes were used to compare water age in SWMPs and SWMP-treated catchments in an urbanizing watershed. We sampled water biweekly from two SWMPs and five stream sites with varying land cover and stormwater control in their catchments. Two inverse transit time proxies (damping ratio and young water fraction) were computed along with the mean transit time (MTT) by sine–wave fitting for each SWMP and stream site using the δ¹⁸O and δ²H data. Water entering the SWMPs was consistently older (224 and 177 days) than water in or exiting the ponds (ranging from 46 to 91 days and 39 to 67 days, respectively). This finding is likely due to a combination of groundwater infiltration into broken sewer pipes that transport water into the ponds and a bias toward baseflow sampling. At the catchment scale, detention provided by SWMPs was not found to be more significant than the interactive effects of impervious cover, surficial geology, land use proportions, and catchment size in determining MTT. Overall, surficial geology explained the most variation in MTT among the seven sites. This study illustrates the potential for isotope-based approaches of water age to provide information on individual SWMP functioning and the influence of SWMPs on catchment-scale water movement.     

Hydrological transit times in nested urban and agricultural watersheds in the Greater Toronto Area,Canada

Watershed mean transit times (MTTs) are used to characterize the hydrology of watersheds. Watershed MTTs could have important implications for water quality, as relatively long MTTs imply lengthier water retention, thereby allowing more time for pollutant transformation and more moderate release of pollutants into streams. Although estimates of MTTs are common for undisturbed watersheds, only a few studies to date have applied MTT models to urbanized watersheds. In the present study, we use δ¹⁸O to compare estimates of MTTs for paired suburban‐industrial and agricultural watersheds in Toronto, Canada. Although differences in precipitation δ¹⁸O between the two watersheds were negligible, there were significant differences in stream δ¹⁸O, suggesting differences in water transport pathways. Less damping between input precipitation δ¹⁸O and output stream δ¹⁸O in the suburban‐industrial watershed indicated a larger streamflow contribution from quick‐flow transport pathways. We applied three transit time models to quantify MTTs. Considering overall model fit, root mean square error, and uncertainty in model parameters, the exponential model performed the best of the three models. Optimized MTTs using this distribution across the suburban‐industrial subwatersheds ranged from 2.1 to 2.9 months, whereas those in the agricultural subwatersheds ranged from 2.7 to 7.5 months. The relatively small difference between urban and agricultural MTTs coincides with observations elsewhere. Model efficiencies could potentially be improved, and MTTs estimated more reliably, with a higher sampling frequency that captures a greater volume of overall discharge. Overall, this work provides a distinct first glimpse into the separation of MTTs between paired watersheds with such a large contrast in their land use.     

中国都市圈中运量型轻轨交通的发展问题研究

从都市圈的空间结构和交通需求的特点分析入手,讨论了中运量型轻轨交通在都市圈公共交通中的地位与作用。结合中国都市圈建设中有关轻轨公共交通发展的问题,指出发展以中运量型轻轨交通为骨干的城市公共交通是中国都市圈交通建设的重要方向,并对中国都市圈以中运量型轻轨交通为骨干的都市圈综合交通体系的规划建设提出了若干建议。     

基于MapReduce的海量公交乘客OD并行推算方法

公交乘客出行OD能够反映居民出行特征和出行需求,是进行公交系统评价、调度和线路优化的重要基础数据,对城市规划具有重要的实用价值。现有公交OD推算方法多适用于少量公交数据,无法直接快速地推算海量公交乘客出行OD,因此本文提出了一种基于MapReduce的海量公交乘客OD并行推算方法。首先将公交数据从关系型数据库迁移至HBase数据库;接着利用MapReduce并行计算框架,根据HBase中IC卡数据的Region数量分成多个map任务,每个map任务中Map函数计算上车站点,Reduce函数将上车站点以用户为单位进行归并输出到HDFS;然后在上车记录数据的基础上,根据HDFS存储的块数量分成多个map任务,针对每个乘客的出行记录,综合考虑出行链方法和历史相似出行行为规律实现对公交乘客下车站点较为精确的推算。最后以厦门2015年6月13日至26日的IC卡数据和公交车辆GPS数据进行实例分析,共计算出295条公交线路,16 879 661条上车记录,14 410 058条完整OD记录,占IC卡数据的78.9%,计算效率相比传统方法有较大幅度提升。结果表明：该方法不仅可以较为准确地推算公交乘客上下车站点,而且计算效率较高。     

基于经纬仪的数字化测图实习教学尝试

针对一些高校电子全站仪较少的状况,提出了利用经纬仪进行数字化测图教学实习的思想,在实践的基础上摸索出了用经纬仪进行数字化测图教学实习的成功经验,给出了具体的作业方法。     

珠江三角洲城际轨道网络结构：基于连接、容量和流量的对比

城际交通网络包含提供联系可能性的基础设施连接网络（铁轨等）,反映承载容量的组织网络（列车班次等）与实际需求的流量网络（客货流等）3类,分别从连接可能性、潜力容量和实际流量三方面映射了网络发育的不同特征。理清城市在这3种维度网络中的不同位置,对分辨城市的节点位势和城市系统构造具有重要意义。以珠三角城市群城际轨道网络为研究对象,本文系统分析了3种网络整体结构、城市的节点位置和城际连接性的差异。结果表明：虽然3种网络城镇地方中心度均呈现出显著的等级差异特征,相较于需求网络,设施网络和组织网络扁平化特征更为显著;组织网络和需求网络均表现出了以广深为核心、以广深、广珠和广佛为主要联系的结构体系,设施网络则呈现出明显的“沿线效应”,突出了珠江口西岸广珠城际沿线的骨干地位;与组织和设施网络相比,需求网络突出了肇庆、江门等城市的重要性,轨道沿线中小城镇位势则逐渐降低。研究一方面通过区分3种铁路交通网络强调了城市网络研究中明确“刻画何种网络”的重要性;另一方面通过对比城市节点和城际连接在不同网络中的位置,识别出可能性、利用潜力和实际流量的差异,为交通线路规划和区域空间优化政策制定提供依据。     

Android水平位移即时监测终端软件的实现

水平位移形变监测是轨道交通工程中十分重要的一环。随着移动互联技术和智能终端的发展及其在水平位移形变监测中的应用,监测的即时性及数据安全问题显得越来越重要。本文实现了一套基于Android设备的水平位移即时监测终端软件,通过Android设备的蓝牙、网络通信功能,将监测设备、Android设备、监测信息服务平台联系在一起,保证了监测的即时性;内嵌数据加密算法,保证了监测数据安全性。实际轨道交通工程中的应用表明:本文开发的终端软件实现了监测数据的实时采集和处理,提升了监测作业效率;实现了监测数据的加密,完善了工程安全机制。     

回归后香港城市发展的尺度重组：以广深港高速铁路香港段项目的规划过程为例

全球化时代城市问题越来越多的以尺度问题的形式出现,尺度理论为分析城市发展背后的各种动力及其影响提供了新的视角。回归后,特区政府如何与位于不同尺度上的地域组织相互作用,进行尺度重组,是探究香港城市发展与管治的关键问题。本文考察广深港高速铁路香港段从项目构想、方案设计,到咨询及申请拨款的全过程,识别这个过程所涉及的不同尺度的作用者,分析他们的作用方式及作用结果。研究表明,回归后,特区政府主动向上尺度重组以拓展香港发展的腹地,政府间的制度性合作是其尺度重组的重要方式。同时,香港逐渐成长的市民社会是参与城市发展尺度重组的重要力量,地方行动者运用尺度政治从多个尺度建构话语和采取行动,对特区政府的方案进行抗议并引发整个社会的讨论。对香港的案例分析可加深对体制转型背景下地域组织尺度重组的认识,丰富尺度重组的理论内涵;也有助于国家客观地了解香港,为制定合理的政策提供科学依据。此外,内地市民社会逐步萌芽成长,案例中特区政府与香港市民社会互动的经验与教训可为内地政府提供借鉴。