We studied an urban area surrounding railway stations in Kashii, a sub-center located in Fukuoka City, Japan. Applying the concepts of Space Syntax Theory we clarified the macro-spatial characteristics of the urban space. Convex and axial maps were constructed and analyzed to forecast the general functioning of land use and pedestrian volume. The analysis of the attributes of the pedestrian space was conducted using the segment unit, a tool that we defined as each one of the fragments located between the nodes in which the pedestrian network is divided. We also clarified the relationship between three-dimensional building use and pedestrian volumes. Conducting a cluster analysis on pedestrian space with the segment unit, we found six different segment types. From the evaluation of all these factors, we deduced that it is necessary to control building use to improve the quality of pedestrian space and the activities in its area.
The pu 「 pose ofthis fesearch is to analyze the configuration of . open space in Japanese urban area by apPly 童 ng the space syntax theory. and to investigate the relationship between the structure of urban f( )rm and socia且conditions , DConfigurations of open space can be quanti 【 atively characterized by 【 he space syntax theory , 2)Integration value correla ヒ es close 星 y with pedes [rians distribution , 3 ) Di・t・ib・ ti… fth・ b・ ildi ・ g − u ・e d・ es n ・ ヒc ・rrel ・t ・ 【 ・ th・ i・t・ g ・ati・ ・ value b・ t it is a c ・ rrel・te ・ f虻h・ p ・des 啣 di、 . 【 ribution . 4) The space syntax theory carl estimate pedestrian flows and the building − use of fUture plans. 【 tis c … 1・
In this study, we developed a new computational fluid dynamics (CFD) model called Airflow Analyst that deepens the affinity between CFD and geographic information system (GIS). First, a precise simulation of the surface-mounted cube was conducted. Validation testing based on the obtained data confirmed the predictive accuracy of Airflow Analyst. Second, New National Stadium Japan (Tokyo Olympic Stadium) was accurately reproduced in a computer, capturing the latest detailed urban area data for the base. For the target of the constructed 3D models, simulations with a large number of grid points/cells (CFD) were conducted. These simulations reproduced the complex turbulent flow fields both inside and outside the stadium. The experiment successfully reproduced the CFD simulation using a large number of grid points/cells, where the conditions of the wind flow ventilation from the sky were similar to those of the intended stadium design.
SUMMARYThe needs of three-dimensional implementation and WWW-based geographic information systems are increasing. In this paper, we propose a flexible and efficient VRML-based terrain model. In the proposed model, by placing side by side the terrain models (tiles) of fixed size in 3D space, the simplification of display range change, the utilization of a caring mechanism, and the attachment of an automatic changeover mechanism for the level of detail of the model will become possible. Each tile is modeled by combining multiple grid models, and the useless polygons in the sea and lakes are curtailed. Moreover, we propose an automatic changeover mechanism of the level of detail of the model, which regenerates the shape features of the terrain objects such as square and flat. Furthermore, for curtailing the transmitted data, we also propose a method for automatically generating simplified models from the detailed model on WWW terminal side. Finally, the effectiveness of the proposed model is shown by 3D spatial navigation experiments using automatic viewpoint motion.
In this paper, we use an analysis function for gas diffusion known as the Research Institute for Applied Mechanics, Kyushu University, Computational Prediction of Airflow over Complex Terrain (RIAM-COMPACT), which was developed for complex terrain, in Airflow Analyst software, and apply it to the spread and dissipation of a fluid layer (assuming the fluid layer contains COVID-19 particles). First, to verify the prediction accuracy of the gas diffusion using RIAM-COMPACT, comparisons with past wind tunnel test results conducted on simple and complex terrains are presented under neutral atmospheric stability. The results of the numerical simulations carried out in this study show good agreement with the wind tunnel experiments for both simple and complex terrains. Next, a model of the Japan National Stadium (Tokyo Olympic Stadium) was constructed using 3D detailed topographic Advanced World 3D Map (AW3D) data generated by combining high-resolution satellite images. We tried to reproduce the hypothetical spread and dissipation of the fluid layer (assuming the fluid layer contains COVID-19 particles) inside and outside of the Japan National Stadium using Airflow Analyst implemented with the RIAM-COMPACT analysis function for gas diffusion. We paid special attention to the effect of wind ventilation driven by natural wind. The numerical results under various scenarios show that ventilation driven by natural wind is very effective for the Japan National Stadium.
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