城市公共安全——地下场所火灾危险性

采用层次分析方法分析了地下场所的火灾危险性。按地下场所功能不同分为地下商城、停车场、地铁站和娱乐场所,以火灾载荷、火源、人流量、财产损失及疏散和救援为评价因子,建立了地下场所火灾危险性的递阶层次结构模型,建立各层次的判断矩阵,通过计算得到不同功能地下场所的总权重值并进行排序,得到地下场所火灾危险性严重程度为商场娱乐场所地铁站停车场的结论。     

集值映射的次梯度

本文提出了一种新的集值映射的次梯度。讨论了它的闭性和非空凸性,在适当条件下证明了:inf{CF(x_0、y_0)(v)}=sup{ζ(v)|ζ∈■F(x_0,y_0)}■F(x_0,y_0)(v)=[-CF(x_0,y_0)(-v),CF(x_0,y_0)(v)]     

城市公共空间的公共经济学分析

本文从公共经济学的角度 ,分析城市公共空间作为公益物品的特性 ,和开发使用中提供者、生产者和使用者的关系以及目前存在的问题 ,进而提出了有效配置公共空间的竞争性制度安排的原则。     

住宅小区宅间绿地的布置与设计

作为住宅小区主要绿化的手段,宅间绿地在改善居住区的生态环境、为人们提供良好的生活和休息场所方面具有很多优势。文章在分析论述宅间绿地的规划设计的同时,提出住宅小区的宅间绿化要由地面扩展到空间,最终形成立体化的宅间绿地系统设计思路。     

Spatiality of the urban commons: Typo-morphology of the open common spaces in New Belgrade mass housing blocks

The article examines the existing infrastructure of open common spaces within two New Belgrade mass housing blocks (Blocks 23 and 70a) through a typo-morphological analysis. These spaces between the buildings, although the most neglected, underused, and deteriorated components of mass housing neighbourhoods, are at the same time crucial to the quality, vitality and integrated governance of these neighbourhoods. They represent the primary tangible commons in cities and neighbourhoods. The question of urban commons is increasingly present in scientific literature, urban and architectural discourse. Nevertheless, approaches exploring the spatiality of the urban commons are scarce, leading to insufficient understanding of the spatial aspect and potentials of the already existing commons. Therefore, this study includes (1) identification, typological decoding and classification of the common spaces, focusing on the case of New Belgrade blocks, followed by (2) analysis of the spatial patterns and integration of the identified spaces within the blocks. The study confirms the complexity and diverse typology of the common spaces. It finds that the in-between, common spaces contribute to higher integration of different segments of the blocks. The open common spaces have an essential role in humanisation of the blocks, and thus the quality of life in the blocks as integrated neighbourhoods. The findings indicate that the spatial setting of the open common spaces in New Belgrade blocks allows for (re)emergence of collective practices, leading to inclusive and integrated rehabilitation of the neighbourhoods.     

Emerging Workplaces in Post-Functionalist Cities

ABSTRACT

This paper explores new types of workplaces that are emerging due to the growing flexibility in work arrangements and the use of information and communication technologies. In addition to home and office, third places, such as libraries and coffee shops, are increasingly used as temporary workplaces. Moreover, there is a proliferation of co-working spaces that are designed as temporary working locations. Thus, the boundaries between traditional urban functions have become blurred; different functions co-exist in the same spaces, and new functionalities emerge as people take spaces into new uses. We may call our cities “post-functionalist,” ones that are no longer based only on predetermined and designed functions. However, there has been little research on the spatial characteristics of these new workplaces as well as on the social features within these places. These phenomena have been empirically studied through observational studies, interviews, and spatial analyses of three such sites: Café Köket, Meetingpoint, and Helsinki Think Company in the city center of Helsinki. The results reveal new forms of appropriation of public and semi-public spaces for working purposes that have not yet been analyzed in the context of existing urban policies and practices. The findings provide input for future visions and the planning of new workplaces.     

北京市平原区受胁鸟类栖息地识别和评价

在北京分布的受胁鸟类主要分布在平原区,而平原区为城市发展的主要区域,因此,在城市管理中融入受胁鸟类保护的内容十分必要。以北京市平原区分布的24种受胁鸟类为研究对象,以鸟类对栖息地的需求为分类依据,结合国家土地利用分类标准,采用人工目视解译法,在北京市平原区的高清卫星影像图上识别出5类一级鸟类栖息地和17类二级鸟类栖息地,得到北京市平原区鸟类栖息地分布图。使用24种受胁鸟类的空间分布模型掩膜鸟类栖息地分布,得到24种受胁鸟类的预测空间分布,叠加之后获得受胁鸟类丰富度分布格局,结果显示,水域是受胁鸟类丰富度最高的栖息地。将受胁鸟类丰富度分布格局与北京市国家级和市级自然保护区分布叠加进行空缺分析,结果显示:1)北京市的自然保护区多分布在山区,不能有效保护受胁鸟类;2)受胁鸟类的保护与平原区的城市建设、绿地管理关系密切。采用分区统计方法,计算各类栖息地中分布的平均鸟类种类数,作为栖息地保护行动优先级指标,得出湖泊、水库、坑塘、滩地、沼泽地等湿地区域是具有最高保护优先级的栖息地类型,在保护实践资源充足的情况下,应对各类栖息地开展综合保护。该研究首次为北京城市区域受胁鸟类保护提出空间参考和管理建议。     

Synthesis of precision serial flexure systems using freedom and constraint topologies (FACT)

In this paper we introduce the principles necessary to synthesize the complete body of serial flexure system concepts, which satisfy desired design requirements using Freedom and Constraint Topologies (FACT). FACT utilizes a comprehensive library of geometric shapes that represent regions were constraints may be placed for synthesizing flexure systems that possess designer-specified degrees of freedom (DOFs). Prior to the theory of this paper, FACT was limited to the synthesis of parallel flexure systems only. The ability to synthesize serial flexure systems is important because serial flexure systems (i) may possess DOFs not accessible to parallel flexure systems, (ii) exhibit larger ranges of motion, and (iii) enable cancellation of parasitic errors. Geometric shapes that represent motions only accessible to serial flexure systems have been derived and added to the existing body of FACT shapes initially intended for parallel flexure synthesis only. Systematic rules and guidelines have been created that help designers use these shapes to generate every parallel and serial flexure concept that satisfies the desired functional requirements. We demonstrate how to use these shapes to utilize or avoid underconstraint in serial flexure synthesis. A serial flexure system is designed that interfaces the lead screw of a lathe to the carriage that it drives as a case study to demonstrate the theory of this paper.     

高刚度气浮垫气腔槽宽变化规律研究

对具有弹性薄板可变截面积均压槽的高刚度空气静压导轨气浮垫进行分析研究,在气体压力的作用下,环形弹性薄板产生弹性变形,引起节流面积和均压槽深度的变化,使得新结构气浮垫的刚度较之传统已有气浮垫得到明显提高.而节流面积受到气浮垫气腔槽宽的影响,因此,十分有必要研究分析一下弹性薄板和气浮垫气腔槽宽的关系.