PERFORMANCE-BASED SEISMIC RESPONSE OF FRAME STRUCTURES INCLUDING RESIDUAL DEFORMATIONS. PART II: MULTI-DEGREE OF FREEDOM SYSTEMS

The role of residual deformations when evaluating the performance of multi-storey frame structures subjected to ground motion is investigated in this paper. The limitations of damage indices available in the literature, either based on ductility, energy dissipation or a combination of both, in capturing such a significant aspect of the seismic response of frame structures are discussed. The concept of residual deformations as a critical complementary indicator to cumulative damage, introduced in a companion paper (Part I) for single-degree-of-freedom (SDOF) systems, is herein extended to multi-degree-of-freedom (MDOF) frame systems. The seismic performance of multi-storey frame structures, either representative of new designed or existing structures, is investigated, focusing on the response in terms of residual deformations. Residual deformations are shown to be sensitive to the hysteretic rule adopted, to the system inelastic mechanism as well as to the seismic intensity. The influence of higher modes and P-Δ effects on the final residual deformations is addressed. A combination of maximum drift and residual drift in the format of a performance matrix is used to define the system's global performance levels and is then extended to a framework for an alternative performance-based seismic design and assessment approach.     

Has it become warmer in Alberta? Mapping temperature changes for the period 1950–2010 across Alberta,Canada

When a Canada‐wide daily climate time series, covering the period 1950–2010, became available, an opportunity arose to analyze the time series for trends of a variety of temperature indices. The 6,833 climate grid cells covering Alberta, each with an area of 10 km by 10 km, allowed the detailed mapping of 30 temperature indices across the province. From each time series, an annual series was computed, which then enabled trend analyses using the non‐parametric Mann‐Kendall and Sen Slope tests. New maps could be created at an unprecedented spatial resolution, and an associated website was developed to access all trends and changes between 1950 and 2010 for all grid cells at albertaclimaterecords.com . The confidence levels of some temperature trends exceed 99%, while others are below 80%. In Alberta's south, annual average temperatures have increased by 1°C to 2°C since the 1950s, but in Alberta's north the increase is 2°C to 4°C. The growing season has lengthened by between one and five weeks since the 1950s, while the number of frost days has declined. The most significant trends observed were increases in mean annual and winter temperatures, and declines in the number of days below ?20°C and heating degree days.     

An examination of the impact of neighbourhood walking environments on the likelihood of residents of dense urban areas becoming overweight or obese

With the development of urbanization in China, obesity is becoming a serious problem, and the relationship between walking environments and obesity has attracted considerable interest. Using data from questionnaires (n = 418) gathered in 2017 from eight neighbourhoods in Guangzhou, China, a typical high-density city, this study developed an Ordered Logit Model (OLM) to explore the effects of walking environments on the likelihood of residents becoming overweight or obese. The results demonstrate that body mass index (BMI) of individuals living in central urban areas is higher than those of suburban residents. After controlling for the effects of socio-economic factors, it was found that the impact of walking environments at the scale of 1-km buffer on individual BMI is the most significant. Variables of walkability, road network density, bus stop density, metro stop density, green coverage rate, and distance to the park have negative effects on BMI. Based on these findings, it is suggested that planning interventions should focus more on the areas through which residents walk in their daily travel routines. The selection of neighbourhoods surveyed and the sample size limit this study, but the conclusions do provide a scientific basis for the construction of neighbourhoods that encourage walking and decrease the probability of becoming overweight or obese.     

城市群创新投入的空间格局与创新绩效研究——以长江经济带所辖城市群为例

创新投入在城市群内的空间格局是城市群内城市间创新功能分工的综合体现,对城市群整体创新绩效有着较为深刻的影响。基于此,本文以长江经济带6 大城市群为样本,借用城市基尼系数和城市首位度方法,计算了其创新投入的空间格局和演化趋势,并运用面板协整的方法分析了城市群整体创新绩效与创新投入空间格局之间的均衡及因果关系。研究发现：①6 大城市群中长三角城市群、武汉城市群和长株潭城市群的创新资源配置属于单核结构模式,其余的城市群为"双中心"或"多中心"模式;②城市群整体技术创新绩效与创新投入空间格局的城市首位度之间存在"倒U型"关系;③城市群技术创新绩效与城市首位度之间互为长期因果关系,但是从短期看,仅存在城市首位度对技术创新绩效的单向因果关系。     

旅游学分支学科相关性及其进展态势分析——《旅游研究纪事》30年

本文按照旅游学的十个分支学科,对1973-2003年国际旅游学界权威学术刊物《旅游研究纪事》(Annals of Tourism Research)的《主题词索引》(Subject Index)进行了多元相关分析和聚类分析,阐述了这十个分支学科与整个旅游学以及相互之间的相关性,并分别探讨了这十个分支学科各自的进展态势。     

中部地区城乡收入两极分化程度分析及其时空特征变化

ER型指数测算表明,中部地区88个地市(州)城乡居民收入两极分化程度存在明显的时空变化和地区分异;根据2000年、2009年各地市ER指数值,分别将88个地市分为四大类型区,根据2000-2009年各地市ER指数值的变化情况,将88个地市又分为三类地市,综合分析2000-2009年中部地区城乡收入两极分化程度的时空特征变化。分析结果显示:2000-2009年,中部地区城乡收入两极分化程度越来越严重,绝大多数地市的城乡收入极化程度变化呈现出加速上升或一般化上升趋势,各省城乡居民收入两极分化程度也有很大差别;城乡收入极化程度各类型区的空间分布情况发生了明显的变化,各省收入极化程度变化不同类型区的分布存在明显的差异。     

旅游安全网络关注度区域差异研究——基于中国31个省市区旅游安全的百度指数

基于2009-2012年全国31个省、自治区、直辖市的旅游安全网络关注度的百度指数,采用泰尔指数测算方法,分析全国旅游安全网络关注度的区域差异特征,研究发现:1旅游安全网络关注度总体呈现出平稳增长态势,但相比我国互联网上网人数还较小;2区域间、区域内和以省际为单元的旅游安全网络关注度差异显著;3区域间旅游安全网络关注度差异是造成以省际为单元的旅游安全网络关注度差异的主要原因,区域内旅游安全网络关注度对以省际为单元的旅游安全网络关注度的贡献率很小;4西部地区的旅游安全网络关注度省际规模位序低于中部、东部地区,东部地区旅游安全网络关注度指数一直靠前;5整体上,2011-2012年全国和三大区域的旅游安全治理信息的网络关注度较高,所占比重最大;中部地区对旅游安全治理信息的网络关注度明显高于东部和西部地区;2011年和2012年东、中、西部三大区域假日旅游安全信息网络关注度所占比例较接近。     

基于GIS的中国省际人口迁移流的空间特征分析

文章基于中国第五、六次人口普查与2005年1%人口普查数据资料,采用流数据分析方法,运用GIS空间分析技术,选用省际人口迁移的最大联系线、最大迁出流、最大迁入流、期望线、迁移效率、粗迁移率等方法系统地研究了我国1995-2010年间省际迁移的时空动态特点及其区际联系。结果表明:全国省际人口迁移的流动性不断增强,东部地区更明显;省际最大人口迁出与迁入流反映了中国省际区域间空间相互作用整体框架,全国大致可以分为3个人口吸引片区和5个辐射片区;省际最大净迁移流主要分布在东南沿海地区,中、西部地区分布较少,其空间分布与各省的MEI_(i)指数密切相关。     

The Scale of Dissimilarity: Concepts, Measurement and an Application to Socio-Economic Variation Across England and Wales

The paper considers the scale – the measure, extent, and dimension – of uneven distributions in space for a wide range of census variables. While the traditional 'index of dissimilarity' is affected by random as well as social factors, a solution presented here allows the index to be calculated even for very small populations. Small areas across England and Wales tend to be fairly similar demographically but quite diverse on ethnic and socio-economic measures. Differences between areas become more noticeable as we move from districts, to wards, to enumeration districts, but the rate of differentiation depends heavily on the variables considered.     

英国流行人文地理学导论教材之评述与借鉴

选取英国时下流行的两本人文地理学概论教材《人文地理概论》和《人文地理学导论:21世纪的议题》,分析了他们的优缺点,并与美国的同类教材进行了比较。《人文地理概论》基于后现代主义的理念,采用30人的大团队,全新的结构(基础+论题+背景三部分),试图展示当代人文地理学的多样性。后一本教材则以问题为导向,采用21人的大团队,充分利用地图、表格、照片、热点知识窗,用手册性著作的写法,全面展示了当代人文地理学的研究主题;缺点是视觉冲击力不够,缺乏对有关研究取向历史发展的论述。