A high-precision heuristic model to detect home and work locations from smart card data     

Nilufer Sari Aslam  Tao Cheng  James Cheshire 《地球空间信息科学学报》2019,22(1):1-11

Smart card-automated fare collection systems now routinely record large volumes of data comprising the origins and destinations of travelers. Processing and analyzing these data open new opportunities in urban modeling and travel behavior research. This study seeks to develop an accurate framework for the study of urban mobility from smart card data by developing a heuristic primary location model to identify the home and work locations. The model uses journey counts as an indicator of usage regularity, visit-frequency to identify activity locations for regular commuters, and stay-time for the classification of work and home locations and activities. London is taken as a case study, and the model results were validated against survey data from the London Travel Demand Survey and volunteer survey. Results demonstrate that the proposed model is able to detect meaningful home and work places with high precision. This study offers a new and cost-effective approach to travel behavior and demand research.  相似文献   

上游建库引水对健跳港冲淤影响的经验预测     

于传见  黄世昌  姚炎明  唐子文 《海洋学研究》2008,26(3):53-61

从分析健跳港水文和泥沙特性出发,探讨了健跳港水动力和河床演变的基本特征,结果表明,尽管健跳港内落潮最大流速大于涨潮最大流速,但该港泥沙净输沙方向还是朝向港内;流域径流对健跳港海床稳定起着重要作用,维护健跳港冲淤平衡的主要动力来自洪水期的径流.利用水沙关系和河相关系模型预测了健跳港上游引水后对该港海床淤积的影响.  相似文献   

Communities structure of the planktonic halophiles in the solar saltern of Sfax,Tunisia     

Jannet Elloumi  Jean-François CarriasHabib Ayadi  Télesphore Sime-NgandoAbderrahmen Bouaïn 《Estuarine, Coastal and Shelf Science》2009

The composition and distribution of the main planktonic halophilic micro-organisms (heterotrophic and autotrophic picoplankton, nanoplankton, phytoplankton, ciliates) and metazooplankton were investigated in six ponds of increasing salinity in the solar salt works of Sfax, Tunisia, from January to December 2003. Marked changes in the composition and biomass of the communities were found along the salinity gradient, especially at salinities of 150 and 350. Autotrophic picoplankton, nanoplankton, diatoms, dinoflagellates and ciliates characterized the less salted ponds. Planktonic biomass was the highest at intermediate salinity as a consequence of a bloom of Ochromonas. Species richness of phytoplankton, ciliates and zooplankton greatly decrease above a salinity of 150 and typical halophiles (Dunaliella salina, cyanobacteria, Fabrea salina and Artemia salina) were found between 150 and 350 salinity. In this environment, F. salina appeared more adapted than the brine shrimp to survive during phytoplankton blooms. The halophilic plankton was however almost entirely composed of heterotrophic prokaryotes in the crystallizers. We thus observed a progressive disappearance of the autotrophic planktonic communities along the salinity gradient. Multivariate analysis of the communities provides evidence that ponds represent discrete aquatic ecosystems within this salt works.  相似文献   

锦州25—1区块探井钻井实践与认识     

魏刚  ;刘小刚  ;陶林  ;张春琳 《海洋地质译丛》2009,(3):71-74

锦州25—1油田是渤海湾近年钻探发现的大型油田。锦州25—1区块先后钻了十多口探井,在钻井作业中遇到上部井眼扩大严重、井径不规则、井垮、起下钻遏阻卡、电测作业遏阻、电测井底沉砂较多、井漏等复杂情况。通过对锦州25—1区块前面几口探井钻井中出现的问题进行认真分析,研究了锦州25—1区块的地层压力剖面分布。经过不断的总结与措施改进后,在后面的探井钻井作业中做到了起下钻顺利,上部井径扩大率较小,未出现井垮情况,电测一次到底,钻井作业生产时间大幅度提高,为锦州25—1油田的生产井钻井积累了宝贵的经验。  相似文献   

我国城市群整合发展的基础与实践   总被引：5，自引：1，他引：4  

王发曾  刘静玉 《地理科学进展》2007,26(5):77-99

目前, 我国许多城市群还没有形成以城市集群为支撑的有整体竞争实力的地域实体, 区 域协调机制还没有从根本上建立起来。为了解决这个严重制约城市群发展的问题, 必须走整合发 展的道路, 整合发展是城市群战略的重大课题。城市群的整合发展要树立正确的科学理念, 充分 吸取国内外相关研究的宝贵启示。整合发展的理论基础分核心理论和基本理论, 前者有竞争优 势、空间相互作用、空间发展和区域协调理论等, 后者有系统、现代经济增长、可持续发展和区域 创新理论等。城市群的存在、城市群的要素和城市群地区的城镇化是整合发展的现实基础, 涉及 城市群存在状态的演进及其广域存在价值, 资源秉赋、整体实力、产业结构、交通通信和核心城 市, 城镇化的综合水平和面临的主要问题等。城市群整合发展的实践包含6 个方面的内容: 城市 竞争力整合、城市体系整合、产业整合、空间整合、城乡生态环境整合和发展的支撑平台整合。  相似文献   

面向应用的高校GIS教学探索与实践   总被引：8，自引：2，他引：6  

党安荣  刘钊  贾海峰 《地理信息世界》2007,5(2):9-14

高校GIS教学是近年来国内探讨的热点教学问题之一,涉及到GIS专业课程体系设置、教学内容设置、实践环节设置、教学体制改革等多个方面;但这些探讨主要是针对GIS专业学士学位与硕士学位教学而引发的,较少关注非GIS专业学位的GIS教学问题.本文通过分析清华大学GIS教学发展与现状,结合作者在GIS教学中的探索与实践,从教学平台、教学内容、授课形式、考试方式、教学效果等几个方面,讨论如何开展针对非GIS专业、面向应用的高校GIS教学模式,与全国高校GIS教育工作者共勉.  相似文献   

基于虚功原理的悬索桥隧道式锚碇边坡稳定性分析     

曾钱帮  王思敬 《工程地质学报》2007,15(1):22-32

本文基于虚功原理,结合工程地质勘察资料,在岩层层面和不利结构面组合切割下,由于锚碇工程荷载作用,研究坝陵河大桥西岸隧道式锚碇边坡的整体稳定性。本文的力学分析模型采用多个块体破坏机构的分析方法,假定块体的底面和侧面均达到了极限平衡状态,安全系数可通过功能平衡的虚功原理表达式来求解。功能平衡方程中仅有安全系数一个未知数,条块底部和界面上的法向压力和切向摩擦力并不出现,求解大为简化。  相似文献   

Farming ‘practice’ as temporally and spatially situated intersections of biography,culture and social structure     

Emily Phillips  Ian Gray 《The Australian geographer》1995,26(2):127-132

This paper brings anthropological, sociological and geographical perspectives to bear on the problem of farm sustainability and, in particular, the legitimation of sustainable farm practices. It attempts to lay some theoretical foundations for explanation of the adoption of farming practices which may, or may not, promote sustainability. A brief survey of the literature surrounding these issues finds many of the current theoretical perspectives incapable of fully accounting for the complexity of farming practice. Reductionist decision/rational‐action models, in particular, are found wanting for their lack of both cultural consistency and social/spatial specificity. Instead, this paper promotes a generative structuralist approach directed towards an analysis of social and economic practice in lived space; that is, firmly anchored in long‐term ethnographic research.  相似文献   

诸暨洞室工程稳定性评价     

郭家良  张雷 《上海国土资源》1991,(1):47-58

本文主要根据杭铁诸暨387洞室工程所取得的地质资料及室内岩石物理力学试验指标为依据,对该工程的围岩进行分类、並对围岩进行有限元方法的分析,及对围岩局部块体利用赤平极射投影方法进行稳定性验算,对该工程主体洞室的稳定性作出评价。  相似文献   

把握新机遇实现新发展为实现我局"十五"改革发展目标任务而努力奋斗     

宋祥文 《福建地质》2001,20(2):57-69

这次会议是进入新世纪我局第一次工作会议,是一次总结过去,谋划未来的重要会议,开好这次会议对我局在新世纪实现新发展有着十分重要的意义.会议的主要内容是认真学习温家宝副总理的重要讲话精神,总结回顾"九五"地矿工作改革发展的基本情况,讨论修改我局"十五"改革发展纲要、"十五"前三年经济责任制考核办法和精神文明建设考核办法,安排部署2001年工作.下面我代表局党组作工作报告.  相似文献