广州中心城区免费公园公共交通出行便利度分析

公交车和地铁是普通市民公园休闲的主要出行方式。通过统计公园500 m范围内的公交线路数和1 km范围内地铁站点数,构建公共交通出行便利度模型,比较分析广州中心城区33个免费公园的出行便利度。结果显示：（1）由于历史区位的原因,免费公园的公共交通出行便利度呈现明显的旧城核心指向特征;（2）公园之间公共交通出行便利度差异显著,公园便利度最高值与最低值之间相差近100倍;（3）综合公园的便利度最高,社区公园次之,专类公园最低;（4）地铁对公园公共交通出行便利度的贡献大于公交车。     

古村落旅游地游线固化的路径依赖——世界遗产地西递、宏村实证分析

以西递、宏村为例,分析了古村落旅游地高度集中的旅游线路的形成和固化过程。依据新制度经济学理论,游线固化实质是一个路径依赖的结果,其中大众游客的市场结构、消费文化因素、权力因素、古建保护因素、制度因素和经济因素等形成的正反馈机制是不断加强游线固化效果、形成路径依赖的主要力量。在这些影响因素的共同作用下,目前的线路已经陷入锁定状态(Locked-in),短时间内改变则会由于巨大的机会成本而变得困难重重。黟县及西递、宏村村镇政府必须坚持加大对东部民居保护及旅游设施发展投资,设计多样化的专题旅游线路,多样化发展游客市场,并通过市场的力量促进遗产保护、旅游建设以及社区居民的全面、协调、可持续发展。     

基于结构方程模型的广州城市社区居民出行行为

基于行为主义的视角,从微观的社区层面研究城市居民的出行行为。选取广州市的3 个城 市社区作为案例,以218 个样本数据库为基础,根据研究的侧重点不同分别建立两个结构方程模 型,拟合各变量之间的路径关系。其中居民出行选择的结构方程模型重点分析居民属性、居住 区位与居民出行目的、出行时间、出行方式等出行偏好之间的关系。居民出行决策的结构方程 模型则模拟居民的出行决策过程。结果显示：居民之间由于自身属性不同在出行选择和出行偏 好上存在差异,居民出行行为中居民属性和居住区位是根本,出行目的是关键,居民出行行为可 以概括为“属性决定目的,目的影响行动”。此外,居民的出行行为有其复杂的作用机制和决策 路径,居民的出行决策过程可以解读为性别决策子系统、年龄决策子系统、收入决策子系统和居 住区位决策子系统等4 个决策子系统,各子系统中路径作用的不同使居民属性和居住区位对居 民出行决策产生多重多向的效应,在复合系统的影响下城市社区居民表现出差异化的出行 行为。     

广州市居民的出境旅游行为

20 0 1年 10月到 2 0 0 2年 1月对广州市 70 2名市民进行了抽样调查 ,在此基础上结合广州市旅行社的出境游资料对广州市居民的出境游时间变化、出游目的、出游组织方式和目的地选择行为进行了详细分析 ,探讨了广州市民民的出境旅游行为特征。     

Collapse simulation of a four‐story steel moment frame by a distributed online hybrid test

The collapse of a one‐bay, four‐story steel moment frame is simulated in this study by the proposed peer‐to‐peer (P2P) Internet online hybrid test system. The typical beam hinging mechanism, which is ensured by a strong‐column, weak‐beam design, is reproduced. The plastic hinges at the column bases are taken as the experimental portions, while the superstructure is analyzed numerically by a general‐purpose finite element program. The implicit plastic rotations of the two column bases are treated as boundary displacements. In order to account for the complex behavior of the column bases, the P2P system is modified to use the secant stiffness during iterations, and the physical specimens are designed such that the plastic hinge behavior can be obtained. For this study, the three substructures are distributed to different locations. A large ground motion is repeatedly imposed until the column bases lose their capacity to sustain the gravity load. As a result, significant deterioration is observed at both column bases. The proposed P2P system is thus demonstrated to be able to accommodate multiple‐tested substructures involving unstable behavior. The results suggest that the P2P Internet online hybrid test system provides a reliable means of studying structures up to collapse. Copyright © 2008 John Wiley & Sons, Ltd.     

Earthquake damage detection in the Imperial County Services Building III: Analysis of wave travel times via impulse response functions

The majority of structural health monitoring methods are based on detecting changes in the modal properties, which are global characteristics of the structure, and are not sensitive to local damage. Wave travel times between selected sections of a structure, on the other hand, are local characteristics, and are potentially more sensitive to local damage. In this paper, a structural health monitoring method based on changes in wave travel times is explored using strong motion data from the Imperial Valley Earthquake of 1979 recorded in the former Imperial County Services (ICS) Building, severely damaged by this earthquake. Wave travel times are measured from impulse response functions computed from the recorded horizontal seismic response in three time windows—before, during, and after the largest amplitude response, as determined from previous studies of this building, based on analysis of novelties in the recorded response. The results suggest initial spatial distribution of stiffness consistent with the design characteristics, and reduction of stiffness following the major damage consistent with the spatial distribution of the observed damage. The travel times were also used to estimate the fundamental fixed-base frequency of the structure f₁ (assuming the building deformed as a shear beam), and its changes during this earthquake. These estimates are consistent with previous estimates of the soil–structure system frequency, f_sys, during the earthquakes (f₁<f_sys as expected from soil–structure interaction studies), and with other estimates of frequency (f₁ from ETABS models, and f_sys from ambient vibration tests, and “instantaneous” f₁ from high-frequency pulse propagation).     

基于物联网的气象观测站电量在线检测方法

针对目前气象观测设备中蓄电池电量的在线检测装置几乎空白的现象,综合运用蓄电池的交流注入法检测、物联网等技术,电池两端注入交流横流信号,通过蓄电池的相位角和内阻计算蓄电池电量,在实际应用中对检测流程进行了实验和改进,增加了Kalman滤波降低干扰,实现了蓄电池电量的可靠直接在线测量。并根据此方法给出了硬件电路的具体实现,在实际业务中进行了应用,具有较高的可操作性、准确性、一致性。     

城市功能区视角下基于POI数据的公共厕所空间布局合理性研究

公共厕所作为最典型的公共设施,反映出城市的文明程度和管理服务水平,是打造城市文明形象的重要窗口。当前的研究主要集中在公共厕所的可达性和覆盖范围,把公共厕所当做空间上的点无差别对待,忽略了不同功能区公共厕所空间分布所异质性的问题。如何建立全面精准的公共厕所空间评价体系,分析不同区域公共厕所的综合服务能力在当前研究中明显不足,不利于公共厕所的配置规划和基本公共服务均等化的推进。多源数据的涌现为城市公共设施的研究提供了新视角,为此本文提出一个城市功能区视角下基于POI大数据的公共厕所空间布局合理性评价方法。利用词频-逆文本频率(Term Frequency-inverse Document Frequency,TF-IDF)信息加权技术,结合兴趣点(Point of Interest,POI)频率密度识别城市功能区,融合OpenStreetMap(OSM)路网密度数据和WorldPop人口数据设立人口出行活力指数,对城市功能区内的公共厕所服务进行评价;最后计算人口和空间覆盖率以及空间不平衡指数,判别街镇间的差别与街镇内公共厕所布局的合理性。该方法以多源数据为基础,定量分析不同功能区内公共厕所...     

居民出行视角下的北京市双枢纽机场可达性研究

相较于传统的网络分析,利用在线地图API可以更加准确地获取实时出行时间数据。本文基于高德地图API,在居民出行视角下解析北京首都国际机场（“PEK”,简称“首都机场”）和北京大兴国际机场（“PKX”,简称“大兴机场”）在驾车和公共交通2种出行模式下的可达性空间格局,尝试对双枢纽机场可达性以及城市的“民航+城市交通”一体化发展提出建议。结果表明：(1)大兴机场的投用使北京市民航服务在空间分布上趋于“南北均衡”,两机场分别在驾车出行0.5 h和公共交通出行1 h的覆盖范围形成互补,有效提升了城市内部腹地的覆盖;(2)在以北京为起止点的出行视角下,驾车出行的1 h覆盖范围开始出现重叠;而公共交通出行模式的1.5 h范围呈现重叠;(3)驾车出行模式下的机场可达性高于公共交通出行模式,且在公共交通出行模式下,北京市两机场1 h服务面积和人口数量均有待提高,亟需打造“1 h公共交通服务圈”;(4)在以北京为中转点的视角下,首都机场到各火车站的可达性高于大兴机场;未来应重点提升大兴机场-城市交通枢纽的可达性,以提升城市内部中转能力。本研究有助于为双枢纽机场城市的“民航+城市交通”一体化发展提供科学依...     

Modeling relationships between the network distance and travel time dynamics for assessing equity of accessibility to urban parks

Static models of accessibility are usually based on the fixed distance or Average Travel Time (ATT) models. Because of ignoring the traffic as a dynamic process affecting the accessibility through the change of Travel Time (TT), these models lead to unperceived temporal inequities. In contrast to the consideration of the temporal Variation of TT (VTT) in the previous studies, the variation of traffic- related TT and its relations with network distance has not been considered. In this study, relations between VTT and network distance to access urban parks in Tehran megacity has been modeled. Traffic maps at five times of day are used to produce TT maps of Traffic Analysis Zones (TAZs) to their 3-closest parks. Comparison of the Gini coefficients of accessibility show significant inequities of accessibility at different times of day. Relations between the distance, ATT, and TTmax are modeled by statistical analysis. Results show both TT and TTmax have significant positive relations with distance and traffic and reach their maximum at 6 p.m. Observation of significant relations between distance, ATT, TTmax, and VTT provides interesting knowledge for the conversion of temporal measures of equity (TT) to a physical measure of equity (distance). A simple application of these findings for effective management of the spatiotemporal inequities is the definition of critical distances from public services. As an example, to decrease the TTmax of TAZs to less than 12 min, their maximum distance to the closest parks should be less than 4 km. The developed approach can be adopted for the accessibility evaluation of the other public services, particularly the health and education centers.