Spotlight on housing and urban change

Journal of Housing and the Built Environment -     

Climate change and China's mega urban regions

China’s mega urban regions are focal points of economic development and environmental concerns. This paper positions four mega urban regions (i.e., the Yangtze River Delta, the Pearl River Delta, the Bohai Bay Area, and the South-eastern Fujian Province) along China’s coast into the national economy and elaborates their development challenges and planning innovations. Mega urban regions in China are spatial consequences of rapid economic transition. They deserve close scrutiny and demands for innovative planning responses in order to maintain their key role in driving economic growth but limiting their greenhouse gas emission.     

为什么城市规划体系必须改变

城市规划从业者、研究人员以及许多非专家承认,在世界上很多地方,城市规划体系必须改变,因为城市规划体系没能解决广泛存在的问题,联合国人居署政策分析处处长Naison D．Mutizwa—Mangiza写道。     

强化近期规划促进城市规划思想方法的变革

自<国务院关于加强城乡规划监督管理的通知>和建设部等九部委局关于贯彻落实国务院通知的通知发布以来,近期规划的作用得到了强调,近期规划也成为了当今城市规划实践、制度建设以及理论讨论的重点和热点内容.其实,近期规划并不是一个新问题,也不应该是一个新问题,之所以要如此的强调,我以为这是针对于我国城市规划体系中一直存在的、也是当前非常突出的城市规划实施问题所提出的一种策略.     

新城市时代的土地和气候变化问题

联合国人居署的预测显示,未来几十年,全球城市人口增长的95％将出现在发展中国家.城市化水平将不断提高,本世纪,亚洲和非洲城市化水平最低的地区将从农村社会转变为以城市为主的地区.到2050年,发展中国家的城市人口将达到53亿,而亚洲城市人口将占全世界城市人口的63％,即33亿人.     

Emergent Urbanism: structural change and urban planning and design

In response to the structural changes of recent decades, many European cities and towns have invested in production, consumption and transportation infrastructures, marketing and branding measures, and urban design schemes, in order to manage and stimulate urban regeneration. This paper contributes to a discussion of urban planning and design in the context of structural change, emphasizing the consequences that such change has had for urban heritage and the sense of place. The paper addresses two cases from Swedish infrastructure planning practice to construct a conceptual framework for the discussion and analysis of contemporary theory and practice in urban planning and design. Throughout this paper, we argue that the urban landscape should not be seen as solely resulting from deliberate planning and design measures. Rather, understanding the regeneration of that landscape requires a deeper consideration of decisions related to infrastructure planning, as well as emergent processes of economic, social and spatial processes of structural change. We put forward the term Emergent Urbanism to describe this expanded understanding.     

城市战略在所候变化方面必须协调一致

在过去的十年里,气候变化问题已经从一个少数开拓型城市当局倡导的议题逐步转变为全球各城市的主流议题.涉及气候变化的市政网络数量在不断增加,其成员也各有不同,世界各地的城市纷纷加入其中,这表明,人们逐步意识到了城市在气候变化和温室气体浓度不断增加影响下的脆弱性.     

The urban household pattern of daytime population change

A matrix representation of places of residence and places of commuting destination in a metropolis, is coupled with evidence regarding spatio-temporal change in average household size. This approach allows the average number of persons per household who commute to be hierarchically ordered in a square matrix which shows attributes associated with a well-known class of matrices. Based on these attributes it is shown that any given spatial distribution of households implies a bounded range of vectors representing the spatial distribution of commuters. Two related distributions correspond to night-time and daytime populations in the metropolitan subareas. Whereas much of contemporary urban modelling is rooted in economic considerations, this alternative approach replaces explicit economic reasoning with some speculative considerations. The proposed methodology is applied to thirty four subareas throughout the city of Saskatoon, Saskatchewan.     

Integrating spatial optimization and cellular automata for evaluating urban change

Urban growth and change presents numerous challenges for planners and policy makers. Effective and appropriate strategies for managing growth and change must address issues of social, environmental and economic sustainability. Doing so in practical terms is a difficult task given the uncertainty associated with likely growth trends not to mention the uncertainty associated with how social and environmental structures will respond to such change. An optimization based approach is developed for evaluating growth and change based upon spatial restrictions and impact thresholds. The spatial optimization model is integrated with a cellular automata growth simulation process. Application results are presented and discussed with respect to possible growth scenarios in south east Queensland, Australia. Received: August 2001/Accepted: July 2002 The second author was supported by a grant from the Australian Research Council.     

A multi-scenario forecast of urban change: A study on urban growth in the Algarve

The Algarve region in Portugal is often considered as one of the most appealing regions for tourism in the country. Its attractive location and moderate climate have since the mid-1960s brought increasing economic prosperity. As a result of the development of mass tourism, available land-use resources were widely exploited to create an integrated tourist industry. In this area, economic prosperity has led to an increasing population and a significant growth of infrastructures to cope with the demand from the hospitality sector. The far-reaching land-use changes have, however, led to high pressures on the coastal areas of the Algarve. This region has shown an increasing loss of ecosystems resulting from the expansion of urban areas. This paper proposes a dynamic assessment of urban growth in the Algarve based on non-linear complex system modelling by using cellular automata converging on qualitative story lines with quantitative spatial methodologies. This new methodology utilizes both quantitative and qualitative spatial results by a comparative validation of built scenarios, in order to highlight future land use trends. In particular, three scenarios will be explored, each with distinct specific socio-economic paths. Our analysis to identify the scenario with the best fit, based on the evolution of the actual 2006 land cover, enabled us to build a future urban growth model for 2020 which was quantitatively assessed. The outcome suggests a picture of continuing growth for the region of the Algarve within the framework of current policies and regressive spatial trends.     

攀枝花城市变迁与资源开发的关系

分析探讨了攀枝花市建设初期、综合发展时期、全面开发建设时期的城市特点,通过分析不同阶段城市特点与该阶段资源开发的关系,从中找出资源型城市的可持续发展之路。     

Ventilation strategy and air change rates in idealized high-rise compact urban areas

We regarded high-rise compact urban areas as obstacles and pathways to the approaching wind. Flow rates across street openings, open street roofs and along street networks contribute to air exchange between urban airspaces and their external surroundings. We numerically studied the ventilation and air change rates in some aligned square building arrays (the building width B = 30 mm, building heights H = 2B or 2.67B) with building area densities of λ_p = 0.25 or 0.4 (i.e. the ratio between the plan area of buildings viewed from above and the total underlying surface area). The main and secondary streets are parallel and perpendicular to the approaching wind respectively. Urban parameters are found important to the ventilation. The taller buildings (H = 2.67B) may capture larger inflow rates across windward street openings than the lower (H = 2B). Wider streets and smaller building area density provide more wind pathways and obtain larger flow rates along street networks. Meanwhile, the flow rates along the street may quickly decrease due to strong resistances produced by high-rise buildings, so the total street length should be limited, otherwise the ventilation in downstream regions is not good. The secondary streets always experience worse ventilation than the main streets. A building height variation benefits ventilation in the secondary streets by enhancing vertical mean flow rates across street roofs in contrast to those with uniform heights. If the base of all buildings is open from z = 0 to 0.33B, the ventilation in both the main and secondary streets becomes better.     

Citizen engagement and urban change: Three case studies of material deliberation

Public participation in urban planning and development is a widely used process which seeks to enable better decision making. In this paper we address critiques of such deliberation – that it relies on the discursive to the detriment of experiential, material or affective modes of expression – and describe three case studies of participation which emphasise, in different ways, ‘material deliberation’. We close by discussing the ways in which such material deliberative practices can best be understood as components of a wider deliberative society.     

Long-run urban dynamics: understanding local housing market change in London

Abstract

Recently, a literature has emerged using empirical techniques to study the evolution of international cities over many centuries; however, few studies examine long-run change within cities. Conventional models and concepts are not always appropriate and data issues make long-run neighbourhood analysis particularly problematic. This paper addresses some of these points. First, it discusses why the analysis of long-run urban change is important for modern urban policy and considers the most important concepts. Second, it constructs a novel data set at the micro level, which allows consistent comparisons of London neighbourhoods in 1881 and 2001. Third, the paper models some of the key factors that affected long-run change, including the role of housing. There is evidence that the relative social positions of local urban areas persist over time but, nevertheless, at fine spatial scales, local areas still exhibit change, arising from aggregate population dynamics, from advances in technology, and also from the effects of shocks, such as wars. In general, where small areas are considered, long-run changes are likely to be greater, because individuals are more mobile over short than long distances. Finally, the paper considers the implications for policy.     

谈城市立体交通工程市政管线迁改设计

以港珠澳大桥珠海连接线管线迁改工程为例,分析了该管线迁改项目的特点、重点及难点,并制定了项目开展的技术方案,从设计条件、既有管线保护等方面,总结了项目设计过程中的注意事项,从而确保了项目建设的顺利实施。