地震带城市规划模型设计与仿真

传统三维城市规划模型是利用三维技术通过计算机生成模型对城市进行规划,没有考虑城市地理位置因素,不能保障城市震后应急救灾工作效率。为此,构建一种新的地震带城市规划模型。通过对城市抗震防灾空间及防灾分区定义,并对其规划原则进行分析,从而为城市防灾空间规划提供依据;以此为基础,采用风险评估方法构建出地震带城市抗震防灾空间规划的基本模型。实验结果表明,所设计模型性能极佳,考虑到了城市地理因素,在进行城市规划的同时,能够促进城市震后应急救灾工作的高效运行。

虚拟世界平台作为城市规划模型的应用探析——以美国纽约社区公园规划为例

虚拟世界平台创造了一个新的规划模型工具。本文从输入、算法、假设和输出四个要素探讨了虚拟世界作为城市规划模拟模型的理论可行性,进而以虚拟世界平台"第二人生"在美国纽约皇后社区着陆灯公园规划案例中的应用实例分析,表明虚拟世界平台作为城市空间规划模拟模型具有现实可行性,虚拟世界平台在城市规划领域应用的广阔前景已经显现。本文通过理论和实例分析指出,虚拟世界作为城市规划模型工具可以为城市规划应用提供实验场所、交互平台、虚拟现实和平行世界四个层次的平台支撑。

城市引擎在智慧城市规划中的应用

针对智慧城市规划和建设存在的问题,利用已有地理信息多元数据,在CityEngine中进行城市规划三维建模。通过数据处理、几何建模和场景输出,建立了基于城市规划分析的三维模型,并实施了建筑体量调整、规划指标分析和日照分析,实现了参数调整和指标符合性验证。实验结果表明,基于CityEngine的三维城市规划模型可充分利用已有数据,实现快速建模,降低建模成本,缩短建模周期,同时计算机生成建筑模型语言具有良好的参数调节性,可实现规划指标动态调整。

Dynamics of Wetland Landscape Pattern in Kaifeng City from 1987 to 2002

It is very significant for urban development and urban wetland protection and utilization to probe into the process and reasons of urban wetland landscape dynamics. Taking the information of remote sensing and detailed land survey data as the basic information sources, with the help of RS and GIS, according to the principles and methods of landscape ecology, this paper analyzed wetland landscape pattern dynamics and its reasons in Kaifeng City, Henan Province of China, from 1987 to 2002. The results show that the total wetland area in Kaifeng City firstly reduced by 20.1% from 1987 to 1990 and then increased from 1990 to 2002, with an average annual growth rate of 3.3%. At the same time, landscape fragment degree and landscape dominance degree increased, respectively from 0.64 to 0.72 and from 0.3754 to 0.5563, but mean patch area, maximum patch area, patch fractal dimension reduced. As far as single landscape element concerned, fi＇om 1987 to 2002, patch area, patch number, patch density, patch shape and patch location changed in varying degrees in all wetland types in Kaifeng City, among which rice field changed most and others relatively less. In the recent 20 years, rice fields, lake wetlands, puddles and ponds had a higher stability, but river and bottomland wetlands were mostly transformed to land use types. The change of wetland landscape pattern was the result of the combined action of the Huanghe （Yellow） River, urban expansion, wide cultivation of rice, and rapid development of fishery. Among them human activities were the main driving factors for wetland landscape changes.

A multi-objective model for cordon-based congestion pricing schemes with nonlinear distance tolls

Congestion pricing is an important component of urban intelligent transport system.The efficiency,equity and the environmental impacts associated with road pricing schemes are key issues that should be considered before such schemes are implemented.This paper focuses on the cordon-based pricing with distance tolls,where the tolls are determined by a nonlinear function of a vehicles' travel distance within a cordon,termed as toll charge function.The optimal tolls can give rise to:1) higher total social benefits,2) better levels of equity,and 3) reduced environmental impacts(e.g.,less emission).Firstly,a deterministic equilibrium(DUE) model with elastic demand is presented to evaluate any given toll charge function.The distance tolls are non-additive,thus a modified path-based gradient projection algorithm is developed to solve the DUE model.Then,to quantitatively measure the equity level of each toll charge function,the Gini coefficient is adopted to measure the equity level of the flows in the entire transport network based on equilibrium flows.The total emission level is used to reflect the impacts of distance tolls on the environment.With these two indexes/measurements for the efficiency,equity and environmental issues as well as the DUE model,a multi-objective bi-level programming model is then developed to determine optimal distance tolls.The multi-objective model is converted to a single level model using the goal programming.A genetic algorithm(GA) is adopted to determine solutions.Finally,a numerical example is presented to verify the methodology.

Joint analysis of urban shopping destination and travel mode choice accounting for potential spatial correlation between alternatives

In recent years,there have been important developments in the joint analysis of the travel behavior based on discrete choice models as well as in the formulation of increasingly flexible closed-form models belonging to the generalized extreme value class.The objective of this work is to describe the simultaneous choice of shopping destination and travel-to-shop mode in downtown area by making use of the cross-nested logit(CNL) structure that allows for potential spatial correlation.The analysis uses data collected in the downtown areas of Maryland-Washington,D.C.region for shopping trips,considering household,individual,land use,and travel-related characteristics.The estimation results show that the dissimilarity parameter in the CNL model is 0.37 and significant at the 95% level,indicating that the alternatives have high spatial correlation for the short shopping distance.The results of analysis reveal detailed significant influences on travel behavior of joint choice shopping destination and travel mode.Moreover,a Monte Carlo simulation for a group of scenarios arising from transportation policies and parking fees in downtown area,was undertaken to examine the impact of a change in car travel cost on the shopping destination and travel mode switching.These findings have important implications for transportation demand management and urban planning.

Conceptual Model for Collaborative Planning in Iran with Emphasis on the Role of Urban Planners： A Case Study of Anzali＇s Development Strategy

Nowadays, public participation is one of the most important factors to improve the feasibility, legitimacy and quality of urban plans. In Iran, due to lack of comprehensive understanding about the participation notion and its necessary socio-economic and political infrastructures, participatory decision-making has faced with some serious challenges in both processes of preparing and implementing. The present paper focuses on providing practical strategies for preparing collaborative urban plans in Iran＇s conditions. Also it seeks to answer this question： What is the role of planners to prepare a real collaborative plan？ It is assumed that a conceptual model for collaborative planning can be fitted with Iran＇s conditions by means of integrating the fundamental philosophic ideas of participatory planning such as theories of Paul Michel Foucault and Jürgen Habermas, given the fact that the present situation of collaborative planning in Iran needs a supportive theory which is compatible with power structures of Iranian urban planning system. In this regard, the Habermas＇ theory of “communicative action” and the Foucault＇s theory of “power structures” are reviewed by a comparative analysis methodology to present an integrated conceptual model for collaborative planning in Iran＇s condition. At the end, the CDS （City Development Strategy）---making process of Anzali City of Iran is analysed to examine this claim in the practice. The results yield that enabling urban planners to act as communication facilitators during planning can direct the collaborative planning in Iran from theory to a real practice by means of integrating the positive aspects of communication and power.

Model and algorithm of optimizing alternate traffic restriction scheme in urban traffic network

An optimization model and its solution algorithm for alternate traffic restriction(ATR) schemes were introduced in terms of both the restriction districts and the proportion of restricted automobiles. A bi-level programming model was proposed to model the ATR scheme optimization problem by aiming at consumer surplus maximization and overload flow minimization at the upper-level model. At the lower-level model, elastic demand, mode choice and multi-class user equilibrium assignment were synthetically optimized. A genetic algorithm involving prolonging codes was constructed, demonstrating high computing efficiency in that it dynamically includes newly-appearing overload links in the codes so as to reduce the subsequent searching range. Moreover,practical processing approaches were suggested, which may improve the operability of the model-based solutions.