论我国城市开放空间系统的优化

城市开放空间系统优化是强化生态城市建设,进而推动城市可持续发展的重要途径。本文讨论了我国城市开放空间系统优化的重大意义,指出:城市的可持续发展强烈呼唤生态城市建设,而生态城市建设必须以城市开放空间系统的优化为支撑。解析了城市开放空间系统的空间形态结构和要素组成结构,阐明了开放空间系统的实用功能、生态功能、文化功能、景观功能和调控功能等,提出了城市开放空间系统优化的理论基础和应遵循的基本原则。在此基础上,着重论述了城市开放空间系统优化的基本对策和空间布局结构优化、圈层一体化优化、系统要素优化等主要工作内容。     

我国农村救护车资源布局优化:以河南省郸城县为例

优化农村救护车资源的配置有助于缩短急救服务的响应时间,对于维护重症伤(病)员的生命安全具有重要意义。本研究以河南省郸城县为例,将15分钟作为急救车路上所需响应时间,研究了该县当前救护车资源布局下农村居民的可达性;应用ArcGIS中的p-中位模型优化了郸城救护车布局点,并运用SPSS16中的配对样本t检验对比了优化前后郸城居民救护车服务可达性变化;应用ArcGIS中的最小覆盖面模型求解了覆盖郸城县域所需的最少救护车布局点数。研究显示,通过优化能有效提高居民的救护车资源可达性,在县域范围内布局13个左右的救护车资源能基本覆盖所有居民点。这一数量对与郸城具有相似自然社会背景的黄淮海平原县域具有借鉴意义。最后,文章还讨论了研究存在的局限。     

基于特色产业簇群的城市群空间结构优化研究

城市群在区域经济社会发展中的作用越来越重要。阐述了产业簇群理论、层域理论、空间相互作用理论和生态学理论等城市群空间结构优化依据。深入分析了特色产业簇群视角的城市群空间结构演变过程。构建了全球、国家和区域等不同尺度的廊道组团网络化城市群空间结构优化模式。最后,作者提出了思想观念创新、市场一体化建设、城乡统筹协调发展、特色产业簇群培育等城市群空间结构优化路径等。     

中国东北地区四中心城市功能关系优化

大连、沈阳、长春、哈尔滨是中国东北地区4个大区级中心城市,在新的历史时期其城市功能定位和发展关系协调至关重要。论文认为,未来15年,沈阳的政治、文化、信息中心作用不会改变,但是,面对其他城市的快速发展和竞争,其大区"龙头"作用特别是经济核心地位会相对下降。大连会渐显其大区核心地位和"龙头"作用。长春、哈尔滨市的次级中心地位依旧,分别承担起国家汽车、光电子、现代农业基地和重型装备制造业、冰雪旅游、对俄贸易中心的功能。     

Simple Homogenization-Topology Optimization Approach for the Pushover Analysis of Masonry Walls

ABSTRACT

A topology optimized rigid triangular FE macro-model with non-linear homogenized interfaces for the pushover analysis of in plane loaded masonry is presented. The shape of the mesh and the position of the interfaces is evaluated through a topology optimization approach that detects the main compressive stress fluxes in the structure. Different values of the horizontal action are considered to derive an adaptive mesh or an optimal discretization that is suitable for multiple loads. Masonry properties are calibrated by means of a homogenization approach in the nonlinear range. To tackle elastic and inelastic deformations, interfaces are assumed to behave as elasto-plastic with softening in both tension and compression, with orthotropic behavior. The two-step procedure competes favorably with classic equivalent frame approaches because it does not require a-priori assumptions on the mesh and on the length of the rigid offsets. An example of technical relevance is discussed, relying into a multi-story masonry wall loaded up to failure.     

资源系统支撑下的乡村旅游地多中心治理研究

乡村旅游地开发已经成为农村经济发展的积极政策选择。本文立足资源与环境的约束,探索根据公共型、公用型和私人型三类不同乡村旅游地形态,分别构建稳健的多中心治理结构,通过“官、产、民、学、媒”等利益主体不同模式下的职能划分与协作互促实现利益均衡和价值最大化,促进乡村旅游地可持续开发目标的实现。     

New Indices for the Existing City-Centers Streets Network Reliability and Availability Assessment in Earthquake Emergency

During earthquake emergencies in existing city-centers, streets network permits inhabitants to reach safe areas, and rescuers to access damaged zones and help population. However, the network can suffer from blocks due to debris of collapsed or heavily damaged buildings. Understanding urban fabric modifications and classifying elements vulnerability are fundamental steps while dealing with risk-assessment and risk-reduction strategies. This article offers a first quick approach for assessing seismic vulnerability of paths network by considering interferences with building heritage damages. Quick data about existing urban fabric (e.g., buildings typology; streets and buildings geometries) are combined for developing new vulnerability indices for streets network. The earthquake macroseismic intensity is introduced for evaluating probable street blockages and summarizing the overall rating of risks in critical network locations, thus intensity that is not included in other current quick methods for streets-building interference is here taken into account. Risk-reduction strategies based on the proposed indices could minimize the interventions on architectural heritage, maximizing the safety of evacuees. These new indices could be combined with traditional assessment of buildings vulnerability, and evaluations on pedestrians’ and vehicles evacuation flows, for evaluating management strategies.     

Seismic vulnerability assessment of historical centers at urban scale

Seismic prevention and mitigation of historical centers have gained a central position within earthquake engineering topics, particularly in areas such as Italy, Greece, and Portugal. Many historical towns in these countries have been strongly damaged, due to the high quantity of old buildings and urban structures and infrastructures. In this article, these aspects are described, modeled, and investigated in terms of structural safety, the goal being the set-up of a comprehensive strategy for seismic prevention and mitigation of a whole historical center. The proposed approach is based on two relevant parts: the first is an urban risk assessment, the second is a prioritization of retrofitting interventions so as to optimally increase urban safety.

The effectiveness of the proposed methodology is shown with reference to a complex case study, the historical center of “Montebello di Bertona”. It is initially modeled as a series/parallel system and then studied by applying seismic reliability methods. Seismic retrofitting interventions are finally prioritized.     

中国产业在东亚的优势及结构调整

中国产业的发展已进入了按国际分工构来选择和实施战略性调整的关键时期。本文采用比较优势指数及贸易特化系数,分析了中国与东亚各国和地区贸易中工业制品的比较优势及竞争优势的状况,指出中国与东亚的产业国际分工的特征、竞争与互补关系以及如何重构中国产业竞争优势的问题。     

伟人故里“红三角”旅游产业优化研究

湖南省韶山、花明楼、乌石红三角是伟人毛泽东、刘少奇、彭德怀的故乡,是极具盛名的革命纪念地和国内外最具影响力的红色旅游品牌。本文较全面分析了红三角旅游产业规模较大、旅游产品已趋成熟、旅游品牌知名度很高、旅游设施较为齐全的良好发展态势;同时客观指出了红三角所存在的旅游产业发展水平不高、旅游产品单一、旅游管理体制不畅、旅游发展水平不平衡等问题;在此基础上,提出了红三角旅游产业优化的基本思路,即优化旅游开发空间布局、构建红色旅游产品体系、培育全国红色旅游第一品牌、策划红色旅游重大开发项目、构建旅游产业集群、加强旅游区域联动、创新旅游管理体制,以促进红三角旅游业可持续发展。