应用复杂网络理论的城市路网可靠性分析

城市路网作为一种关系居民日常生活、社会经济发展的重要网络,在受到暴雨洪水、交通堵塞以及遭遇破坏时,可能局部失效,进而影响整个路网的运输能力和效率。本文针对城市路网的拓扑特点,以复杂网络理论为基础,对两种不同布局结构的路网分别采用主方法和对偶方法建模,分析比较其复杂网络特性,并在此基础上进行了基于节点度和基于节点中介中心性的选择性破坏实验,最后分析了不同结构的路网在不同攻击策略下所表现出来的可靠性。     

Population-adjusted street connectivity,urbanicity and risk of obesity in the U.S.

Street connectivity, defined as the number of (3-way or more) intersections per area unit, is an important index of built environments as a proxy for walkability in a neighborhood. This paper examines its geographic variations across the rural-urban continuum (urbanicity), major racial-ethnic groups and various poverty levels. The population-adjusted street connectivity index is proposed as a better measure than the regular index for a large area such as county due to likely concentration of population in limited space within the large area. Based on the data from the Behavioral Risk Factor Surveillance System (BRFSS), this paper uses multilevel modeling to analyze its association with physical activity and obesity while controlling for various individual- and county-level variables. Analysis of data subsets indicates that the influences of individual and county-level variables on obesity risk vary across areas of different urbanization levels. The positive influence of street connectivity on obesity control is limited to the more but not the mostly urbanized areas. This demonstrates the value of obesogenic environment research in different geographic settings, helps us reconcile and synthesize some seemingly contradictory results reported in different studies, and also promotes that effective policies need to be highly sensitive to the diversity of demographic groups and geographically adaptable.     

Defining and generating axial lines from street center lines for better understanding of urban morphologies

Axial lines are defined as the longest visibility lines for representing individual linear spaces in urban environments. The least set of axial lines that cover the free space of an urban environment or the space between buildings constitute what is often called an axial map. This is a fundamental tool in space syntax, a theory developed by Bill Hillier and his colleagues for characterizing the underlying urban morphologies. For a long time, generating axial lines with the help of some graphic software has been a tedious manual process that is criticized for being time consuming, subjective, or even arbitrary. In this article, we redefine axial lines as the least set of individual straight line segments mutually intersected along natural streets that are generated from street center lines using the Gestalt principle of good continuity. Based on this new definition, we develop an automatic solution for generating the newly defined axial lines from street center lines. We apply this solution to six typical street networks (three from North America and three from Europe) and generate a new set of axial lines for analyzing the urban morphologies. Through a comparison study between the new axial lines and the conventional or old axial lines and between the new axial lines and natural streets, we demonstrate with empirical evidence that the newly defined axial lines are a better alternative for capturing the underlying urban structure.     

资阳市城市街道日照条件分析

随着城市建设的快速发展,城市居民享受＂阳光权＂的问题越来越受到重视,这篇文章利用城市街道日出日落时间公式和计算机程序,推算了四川省资阳市区不同街道走向、不同宽高比（L/H）、从春分至秋分和秋分至春分的可照时数,并据此分析了不同街道走向、宽高比、太阳赤纬等对资阳市城市街道可照时数的影响,得出资阳市以东西走向最为有利,街道宽高比适宜增大更有利于日照;利用四川省资阳市气象局近5年的实际日照时数、云量等观测资料,经过统计分析,得出云量等天空状况对资阳市日照条件有很大影响。     

中华命名观视野下的政区命名对策研究

我国政区名称的命名更名研究经过近30年的研究实践,虽有了一定的进展,但很多问题仍没有得到真正解决,加之第二次全国地名普查已经开始,因此科学规范的政区命名对策,对于全国政区名称的管理具有重要意义.文章分析了当前行政区划命名中存在的问题,叙述了汉语专名命名的基本特征、基本原则和汉语地名命名的五忌等;并根据以上特点,探讨了行政区划命名更名的原则,分析制定了政区名称的命名构想.     

集成不同类型特征的城市道路选取方法研究

道路选取是进行道路网地图综合及多尺度表达时的基础。现有的道路选取方法大多是以道路的语义特征和几何特征作为道路选取的依据,较少考虑道路的拓扑特征。基于此,该文以城市道路网为例,综合考虑道路的语义特征、几何特征和拓扑特征,并以道路综合性能作为城市道路选取的依据,提出一种城市道路选取的新方法。通过实例分析,验证了该方法的有效性。     

深度学习的街景行道树自动识别提取研究

针对城市行道树调查中,街景影像背景环境复杂多变、行道树个体差异大,依靠目视判读费时费力的问题,该文基于车载移动测量系统采集的全景影像数据,利用深度学习算法,在快速区域卷积神经网络的目标检测方法基础上,建立适用于街景行道树检测的深度神经网络模型。模型采用基于共有显著性区域及冗余策略的行道树多示例目标候选区域选择方法,使用车载图像的几何约束进一步筛选合适的候选区域,从而实现行道树目标候选区域的统一选择,提升行道树目标的检测效果。实验结果表明,该文提出的方法能够实现多种行道树的准确自动识别与提取,进而大大降低行道树绿化调查的成本。     

海底地理实体命名关键技术研究

结合我国向SCUFN提交海底地名提案的制定工作,研究了海底地理实体命名工作中涉及的技术标准、数据处理、地理实体识别与分类、海底地名专题图编制,以及管理信息系统建设等关键技术,为我国海底地名工作提供技术参考。     

卫星气象数据业务系统上行信息传输数据流程

介绍了卫星气象数据业务系统中上行气象信息的具体数据流程及有关上行传输设置。