山区交通通达度测度模型与实证研究

交通发展滞后是制约山区发展的重要因素,定量评估山区交通通达情况对认知山区交通空间格局和进行山区交通开发具有重要的现实意义.在综述国内外交通地理文献的基础上,论文构建了以交通设施技术等级、距离交通枢纽的通行时间和交通线密度3个因子为核心的山区交通通达度测度模型,并引入交通摩擦系数来提高山区交通通达度测算的精度.利用该模型...     

Alternatives of strategic environmental assessment for road traffic development planning—Case of Changchun City, China

On analyzing the achievement of the goal in the modern urban road traffic development planning, the alternative of Strategic Environmental Assessment for urban traffic planning should include the basic scheme, the extended scheme and the environmental protection scheme. This study from different perspectives designed the alternatives for Changchun's county-level road and urban road system planning, and used the method of System Dynamics to simulate, optimize and analyze those alternatives. Thereafter, some methods including the correlation function method were used to comprehensively assess and rank those alternatives for recommending two best alternatives with the consideration to the indicators, such as the total emission amount of CO, the total emission amount of nitrogen oxides, the noise value, the road construction cost, the fossil oil consumption and the traffic capacity. The result showed that the study would provide substantial supports for decision-makers to make more scientific decisions and promote the sustainable urban traffic in Changchun City.     

Evolution and paleobiogeography of mangroves

We reviewed the geological record of mangroves based on fossil pollen, fruits, and wood evidence of Nypa, Avicennia, Sonneratia, Rhizophoraceae, and mangrove associates to trace the origin, distribution, extinction, and range contraction of paleo‐mangroves during the Late Cretaceous–Miocene time. Our study region covers paleocoastal areas of Indo‐West Pacific (IWP) and Atlantic East Pacific (AEP) region. First, we compiled the mangrove fossil records from the Late Cretaceous till Miocene and identified the migration pattern for Nypa, Avicennia, Sonneratia, Rhizophoraceae members, and mangrove associates such as Acrostichum, Wetherellia, Pelliciera, Aegiceras, Heritiera, Excoecaria, and Barringtonia. Second, we interpreted the paleoclimate shifts which caused the dispersal/extinction of this specialized ecosystem. Lastly, we proposed the future consequences of mangrove diversity for restoration and conservation strategies. First mangroves appeared during the Late Cretaceous, 100–65 Ma, since then their evolution is closely related to sea‐level changes in geological times. The oldest geological record of Nypa palm which prefers broad ecological tolerance is a good example for pantropical distribution of mangroves. High sea‐level and humid climate offered sufficient coastal regions and climate for the development of 12 genera of mangroves in nine families and subsequent proliferation into newer areas during early to middle Eocene (~50–40 Ma). The Eocene/Oligocene boundary crisis heralds the beginning of a biogeographical split between the present‐day eastern and western provinces of mangroves with records of Sonneratia, Rhizophora, Pelliciera, Barringtonia, and Acrostichum. However, during Oligocene and Middle Miocene mangroves occupied the present geographical position with addition of Nypa, Avicennia, and Excoecaria species. Re‐evaluation of Cenozoic records suggests that the climatic conditions of Late Paleocene, end of Eocene, and middle Pliocene were the driving force that led to the evolution and expansion of mangrove flora. During the Neogene, latitudinal contraction, extinction, and migration of mangroves led to the present bipartite distribution. The Himalayan uplift and establishment of Asian summer monsoon toward Late Neogene further affected the coastal dynamics which tailored the mangrove distribution of the Indian subcontinent. Loss of ecological habitats and local extinction forming disjunct distribution of mangroves during the Quaternary have also affected its overall biogeography.     

基于介数中心性的交通拥堵指数计算

本文以北京城市交通为例,选取北京城市路网数据,计算城市路网介数中心性,以反映城市各道路路段的通达情况;并利用北京出租车GPS定点数据,计算实际的交通轨迹.传统的路网介数中心性主要依据各路段最短路径的比重评价理论上的道路通达性,而本文以网络介数中心性为基础,提出动态介数的方法,从城市各路段交通量比重的角度评价各道路实际拥...     

南极航线和航区环境概述

本文汇集了我国南极科学考察前十年（１９８４－１９９３年）的南极考察航线，根据航区和任务，对南极航线进行了分类：对各航区中影响航行的海洋环境状况－诸如低纬地区的热带气旋，中纬地区的温带气旋和高纬地区的绕极气旋等主要灾害性天气系统的生成源地，移动路么荼了介绍；文中还着得活冰的增，减期和浮冰边缘线进行了描述。以求达到对过去十年南极考察航线作出比较客观的评价。     

《福建省交通地图集》的设计与编制

介绍了《福建省交通地图集》的设计与编制,包括图集内容与结构、设计特点以及技术路线与工艺流程等,可为同类专题地图集的编制提供参考。     

北京交通环境污染诊断模拟初步研究

建立了能够用于评估大型城市交通环境污染与气象条件关系的数值模拟技术,即三维边界层光化学数值模式.其中,高分辨率的精细城市边界层气象场、细致的城市地理与环境参数、空气污染物输送扩散与大气化学模拟以及交通废气污染源的分布等诸多因子是实施模拟研究的几个重要环节.从模拟结果看出,各污染物在地面附近浓度相对高值区位于排放源附近和下风方.在边界层顶附近,污染物浓度分布较均匀,分布趋势和气流一致.虽然仅仅考虑了城区污染物本底浓度和主要交通干道机动车的排放,但交通排放对城区污染物浓度的贡献是较大的.     

基于GIS的贵州省公路局交战办信息辅助管理系统的研究与实现

以贵州省公路局交战办信息辅助管理系统的建设为背景,以GIS技术为支撑,结合交通战备工作的特点,对公路局交战办信息辅助管理系统的建设目标与体系构建、系统功能模块、系统实现等进行设计。为有效提高贵州交通战备和运输、抢修的自动化水平,满足平、战时各方面对贵州交通战备信息的需求与处理具有积极作用。     

城市空间扩展的交通脉动规律研究——以济南市为例

随着现代交通技术的不断进步,城市空间扩展呈现新的特点.以济南市为案例,总结城市规模及空间形态与交通模式的脉动变化规律.在不同的交通模式下,济南先后呈现点状、飞地状、轴状和组团状发展形态,而区位优势提升、产业的拉动和乘数效应、机动可达效应和区域协调发展效应则是交通脉动规律的主要动因.     

International Telephone Calls: Global and Regional Patterns

This study examines patterns in international telephone communications, documenting a close relationship between international call volume aggregated by nation and indicators of global connectivity including volume of international trade, tourism and migration. In addition, the analysis documents the existence of a set of national "communities" of callers. The clear orientation of large portions of the world to former colonial powers (e.g., West Africa and North Africa to France), and the separation of the Muslim Middle East and the Chinese-speaking nations of East and Southeast Asia from other calling communities suggest the importance of continuing historic and cultural influences on information flows.