Spatial interaction modelling

Abstract. Spatial interaction (SI) is the process whereby entities at different points in physical space make contacts, demand/supply decisions or locational choices. The entities can be individuals or firms and the choices can include housing, jobs, production quantities, exports, imports, face-to-face contacts, schools, retail centres and activity centres. The first SI models can be grouped under the generic heading gravity models. Their main characteristic is that they model the behaviour of demand or supply segments, rather than that of individuals and firms. This article traces the development of these models from their inception in the early part of the twentieth century to the present. The key advances include the replacement of the gravity analogy by the more general concepts of entropy or information theory, a statistical framework commonly used in physics. With the arrival of the regional science paradigm over 50 years ago, a key challenge has been to broaden these models compared to those arising in spatial economics, thus arriving at a more inclusive probabilistic framework. These efforts are discussed here, as well as inclusion of geographical advances, embracing activities as generators of travel, time-geography, recognition of spatial interdependencies, and use of neuro-computing principles.     

中国城市空间结构绩效研究评析与展望

在我国当前快速城市化的进程中,城市空间结构绩效的优劣直接影响着城市的健康和可持续发展。文章通过回顾我国城市空间结构绩效的研究概况,对其内在机理、评价指标体系、良好绩效的空间结构形态以及提高城市空间结构绩效的措施等主要研究内容进行梳理和评析,并在此基础上展望未来的研究方向,以期有助于该领域在我国的研究获得新的突破。     

从空间结构和生态过程的关系角度看自然

来自生态学领域的空间结构与生态过程的关系模型,是风景园林规划设计处理生态问题的重要依据。为了在庞杂的实验数据和实践案例中对关系模型进行更加系统化的解读和积累,尝试将关系模型总结为3种类型:基本原理型、案例知识型、落地方法型,并分析了各自特点、典型案例和相互关系。     

成渝地区空间结构及其整合研究

成渝地区经济基础相对发达的城市并未连接成片,尤其是区域中心城市之间的地域经济比较落后.因此,成渝城市群还仅仅停留在起步阶段,城市间的互动作用还比较弱.未来成渝地区的发展应注意以下问题:进一步强化区域核心城市的经济实力和提升城市功能,充分发挥区域性交通廊道的带动作用,选择培育第二层级城市,促进城市体系的完善.     

Participatory business modelling

How to generate business is at play in most innovation projects today. Not only Internet-based businesses, but also traditional manufacturing companies with conventional product sales are currently challenged to consider alternative business models: service design, project sales, direct sales, etc. In participatory innovation the core assumption is that a broad spectrum of people, including users, can contribute to innovation. But is it possible to open up the process of business model innovation to participation from a wider circle than those marketing managers who typically devise new business schemes? In this article we discuss two participatory approaches to business modelling that move beyond spreadsheets and Post-it^® Notes: one of using tangible objects to redefine business elements, and another of people themselves role-playing how an organisation can create, deliver and capture value. These approaches were developed in companies and educational settings and have proven extraordinarily successful in initiating conversations about how to innovate business in cross-disciplinary and cross-functional groups of participants. Relying on design theory, we study the ‘moves’ that participants make towards a new network configuration; in particular as such conceptual ‘moves’ are likely to be associated with the concrete, physical movements of people and objects. We claim that these approaches prove very engaging because business model innovation needs a focus on redefining the concepts we use and the roles that actors play in relation to each other.     

Spatial fixed effects and spatial dependence in a single cross‐section

We investigate the common conjecture in applied econometric work that the inclusion of spatial fixed effects in a regression specification for a single cross‐sectional data set removes spatial dependence. We demonstrate analytically and by means of a series of simulation experiments how evidence of the removal of spatial autocorrelation by spatial fixed effects may be spurious when the true data generating processes (DGP) takes the form of a spatial lag or spatial error dependence. In addition, we also show that spatial fixed effects correctly remove spatial correlation only in the special case where the dependence is group‐wise, with all observations in the same group as neighbours of each other.     

考虑土-结构动力相互作用影响的结构神经网络控制

将人工神经网络控制理论应用于软弱地基上建筑结构地震反应的主动控制分析中。通过训练神经控制器NNC (Neural networkController)预测结构控制力 ,由神经模仿器NNE (Neural networkEmulator)预测结构对地震力的反应来修正NNC的输入 ,从而实现结构的主动控制。数值模拟表明 ,神经网络控制系统能够有效地控制结构的地震反应 ,且对地震输入有很好的自适应性 ,在设计神经网络控制系统时 ,应考虑土—结构动力相互作用的影响。     

考虑土-结构相互作用的空间结构抗震研究现状及展望

目前大跨空间结构抗震研究的分析模型主要是基于刚性地基假设.为了更好地反映空间结构在地震作用下的反应性能,有必要把上部屋盖与下部支承结构以及下部地基作为一个整体建模分析.土结构相互作用在高层结构中研究得比较充分,空间结构研究土结构相互作用则较少.本文从土-结构相互作用模型、辐射阻尼以及地震动输入三方面对研究现状进行总结.考虑土-结构相互作用的空间结构抗震的深入研究将有助于空间结构的更合理的抗震设计.     

Selective review of boundary element modelling for the interaction of deformable structures with water waves

A review was conducted of the use of the boundary element method as a solution technique for the nonlinear interaction of deformable structures and finite amplitude waves. The review concentrated on those areas in which modelling difficulties are anticipated: boundaries, waves, time domain analysis, fluid-structure interaction and a coupled finite element and boundary element model. Very little information was uncovered on the nonlinear fluid-structure interaction, although it is anticipated that the fluid domain would be modelled with a boundary element model and the structure would be modelled with a finite element model. The boundary element method appears to be a viable solution technique for the nonlinear interaction of deformable structures and finite amplitude waves.     

城市轨道交通枢纽空间布局适应性研究

轨道交通枢纽是轨道交通客流集散和交换功能的载体,是城市客运体系中不可或缺的环节,其布局一方面受城市空间结构、用地功能和轨网布局形式等的制约,另一方面又对城市空间的拓展和空间结构的优化具有重要的支撑作用.在进行城市轨道交通枢纽空间布局时,应协调好其与城市的空间结构、轨网模式和土地利用规划之间的关系,实现轨道交通与城市空间...     

基于神经网络的大跨空间结构脉动风荷载的随机模拟

研究了大跨空间结构脉动风荷载的随机模拟技术,基于神经网络进行了风速时程的随机模拟。将该数值模拟技术应用于南京奥林匹克体育中心体育场的随机风荷载模拟,计算结果表明了该方法的有效性。     

城市空间扩张及结构演化的制度因素分析

改革开放以来,中国城市的发展环境发生了巨大的变迁,制度力成为深刻影响城市空间扩张与结构演变的关键因素。在转型期,中国只有加快推进地方政府企业化治理体系,土地制度、土地规制等相应的制度性变革,才是实现城市空间的集约增长、理性增长和结构优化的根本之策。     

大跨空间结构发展与对策

详细阐述了大跨空间结构分类及特点,以及对网架结构、悬索结构和膜结构相关设计施工等问题进行了探讨,并总结提出空间结构发展的趋势方向。     

带状空间结构传统聚落的空间承载力研究——以碛口古镇为例

带状空间结构传统聚落规模较小,空间结构多受单一主导因素影响,聚落职能相对单一。在传统聚落旅游资源开发过程中,带状空间聚落职能定位需在区域旅游发展背景之下根据自身特点来制定。该文选取碛口古镇作为带状空间结构传统聚落的典型案例进行研究,分析其区位优势与景观特色,在获取其基础数据的基础之上分析聚落空间发展过程与结构类型,对其主要道路与外部空间进行承载力评价,并从区域旅游资源的角度分析其基础设施承载力,指出碛口古镇应主要发挥其旅游基地镇的作用。     

福建省域空间结构优化机制与实现

福建省域空间结构优化是区域空间形态协调发展的内在要求,是闽台关系转化与台海经济圈构建的现实需要,是经济全球化的内在要求。可通过完善开放的网络体系,超前培育新兴空间节点,增强省内、省域协作能力及对台合作能力,以及优化省域产业布局和协调产业分工等措施,促进空间结构的优化,实现构建滨海都市带和打造台海经济圈的目标。     

A pseudo-microsimulation approach for modelling congested traffic loading on long-span bridges

This paper investigates congested traffic loading on long-span bridges through the use of traffic microsimulation. Six months of Weigh-In-Motion free-flow traffic data (including cars) are used as input for the microsimulation of congested traffic. Key parameters that affect traffic loading are identified in the output of the microsimulation, and these parameters form the basis for a more computationally efficient ‘pseudo-microsimulation of congested traffic’ (PMCT) model. This PMCT model is shown to replicate the traffic loading from full microsimulation accurately and allows long-run simulations, equivalent to 1000 years of congested traffic, to be performed with an acceptably short duration. This reduces the significant uncertainties associated with extrapolating short-run simulation results to long return periods. The 1000-year simulated results from the PMCT are compared with the extrapolated results from full microsimulation, and with the traffic loading from some design codes, for different bridge lengths. Both types of microsimulation are also applied to calculate maximum lifetime loading for two typical long-span bridges – one cable-stayed and one suspension bridge – using influence lines determined from finite-element models.     

张弦空间结构与下部结构静力相互作用分析

根据国内张弦结构项目屋盖的关键受力构件布置方式与支承边界平面水平投影线的组合进行了屋盖结构分类,从屋盖支座设置方式和索初始预拉力入手,分析了张弦桁架结构屋盖在不同支座形式时不同索初始预拉力对下部支承结构的作用力及屋盖结构的力学响应。分析表明,为充分实现张弦屋盖的自身控制功能,降低张弦桁架空间屋盖与下部支承结构的静力相互作用影响,应从屋盖结构总体系的层面综合考虑进行张弦桁架空间屋盖结构的布置,合理确定索初始预拉力,从而正确选择结构静力设计计算模型。     

一种基于Oracle Spatial的WebGIS实现方案

本文论述了WebGIS的特点、发展现状和主要的开发解决方案,介绍了GIS的空间数据和属性数据在Oracle Spatial空间数据库中一体化存储的实现方法,提出了基于Oracle Spatial的客户端方式快速开发WebGIS的解决方案,最后简要介绍了一种基于该方案开发WebGIS系统的运行实例。     

辽中南城市群的空间发展特征分析研究

辽中南城市群是辽宁省经济发展核心区,也是我国重要的工业基地和东北区经济发展的龙头。本文通过对辽中南城市群的地域结构发展特征及其各城市区域的产业发展特征进行相关分析,在空间上和地域上来阐述辽中南城市群的空间发展现状及存在的问题。基于上述问题的分析,同时运用城市间引力模型和潜力模型的定量分析方法,来分析辽中南城市群未来重点发展的城镇。