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本文针对地铁火灾人员逃生这一问题,系统分析了地铁火灾与人员逃生过程与特点,在此基础上,提出了地铁火灾人员疏散时间计算模型。通过实验与软件,对地铁火灾的烟气的温度与扩散进行模拟,确定了地铁火灾人员疏散可用时间,总结了人员疏散所需时间的计算方法。结合了上海某地铁站的实例进行安全性分析,使得本文所提出地铁火灾疏散时间模型得以运用。 相似文献
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The aim of this paper is to achieve a better understanding of computational process activity-based models, by identifying factors that influence the predictive performance of A Learning-based Transportation Oriented Simulation System model. Therefore, the work activity process model, which includes six decision steps, is investigated. The manner of execution in the process model contains two features, activation dependency and attribute interdependence. Activation dependency branches the execution of the simulation while attribute interdependence involves the inclusion of the decision outcome of a decision step as an attribute to subsequent decision steps. The model is experimented with by running the simulation in four settings. The performance of the models is assessed at three validation levels: the classifier or decision step level, the activity pattern sequence level and the origin–destination matrix level. The results of the validation analysis reveal more understanding of the model. Benchmarks and factors affecting the predictive performance of computational activity-based models are identified. 相似文献
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A novel method which integrates the topological flexibility of the level-set approach and the simplicity of point-sampled surfaces is proposed. The grid structure resulted from the level-set approach not only offers a wide range of powerful surface editing techniques for the point set surface editing, but also facilitates the topological change with ease. With the aid of point-based resampling, the method updates the surface shape of the point-based geometry quickly without worrying about point connectivity at all. The point set surface can also change its topology properly whenever a collision with other parts of itself is detected. The experiment demonstrates their effectiveness on several scanned objects and scan-converted models. Four examples of surface editing operations: smoothing, tapering, deforming, and Boolean operations, are presented. 相似文献
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The dispersion of traffic-related pollutants in urban street canyons is of importance for the health and quality of lives. To reveal the inherent principle, researchers have performed a lot of investigations; many dispersion phenomena have also been assessed during recent years. However, the presence of avenue trees in street canyons and their capacity for pollutant dispersion remains partly addressed. In this study, we investigated the effects of avenue trees in urban street canyons on traffic pollutant dispersion. The dispersion of CO concentration in asymmetric street canyons was simulated under varied situations. The computational results showed a good agreement with the experimental data, and the numerical model was validated to be adequate for investigating the pollutant dispersion in street canyons. Then, the numerical simulations were extended to explore the impacts of the effects of avenue trees on CO dispersion; the results indicated that avenue trees generally increase CO concentrations in asymmetric street canyons. When the wind direction is perpendicular to the street axis, a terraced building raises pollutant concentrations at the windward wall and reduces concentration at the leeward wall on the pedestrian levels. Findings of this study are expected to provide significant insight into urban road design and strategy making for avenue tree planting, particularly under the existing worldwide sustainable low-carbon urban development. 相似文献
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Contemporary maritime piracy presents a significant threat to global shipping industry, with annual costs estimated at up to US$7bn. To counter the threat, policymakers, shipping operators and navy commanders need new data-driven decision-support tools that will allow them to plan and execute counter-piracy operations most effectively. So far, the provision of such tools has been limited. In cooperation with maritime domain stakeholders, we have therefore developed AgentC, a data-driven agent-based simulation model of maritime traffic that explicitly models pirate activity and piracy countermeasures. Modeling the behavior and interactions of thousands of individually simulated vessels, the model is capable of capturing the complex dynamics of the maritime transportation system threatened by maritime piracy and allows assessing the potential of a range of piracy countermeasures. We demonstrate the what-if analysis capabilities of the model on a real-world case study of designing a new transit corridor system in the Indian Ocean. The simulation results reveal that the positive past experience with the transit corridor in the narrow Gulf of Aden does not directly translate to the vast and open waters of the Indian Ocean and that additional factors have to be considered when designing corridor systems. The agent-based simulation development and calibration process used for building the presented model is general and can be used for developing simulation models of other maritime transportation phenomena. 相似文献
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On the evaluation of a public transportation network quality: Criteria validation methodology 总被引:1,自引:0,他引:1
M. Carmo M. Guedes Natália Oliveira Sérgio Santiago Georgi Smirnov 《Research in Transportation Economics》2012
A public transportation network serves in adequate way a population if it evolves in time following the existent social reality. Changes made in order to improve service must be analyzed and evaluated. The introduction of modern technology to validate the fare card allowed a quick access to important, although incomplete, data. Databases with only the getting in validation information can be used to construct an origin–destination (OD) matrix, allowing a service quality analysis. Here it is presented a basic methodology to rigorously validate service quality criteria considering what might be interesting for the user. The quality analysis philosophy is the following. First, based on automatically gathered data, one reconstructs the origin–destination (OD) matrix, which contains information concerning the number of passengers traveling between zones of a certain region. The OD matrix is used to calculate some criteria characterizing the transportation network quality, such as traveling times, waiting times at a stop or transport occupation. The reconstructed OD matrix always contains errors, which cause errors in the criteria values. How significant are these errors? This question can be answered using our criteria validating methodology, which is based on statistical analysis. It has been implemented at the urban bus transport system of Porto, STCP, allowing the evaluation of the transportation network quality under a number of criteria and guaranteeing rigorous results. 相似文献
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针对地铁车站环境控制系统设计中常用的几种典型气流组织方案,使用计算流体力学(CFD)的方法,采用重正化群双方程紊流模型,对待建地铁车站及其隧道内的温度场和气流速度场进行三维数值模拟,得到各种方案下的温度和气流速度分布。通过分析和比较,认为屏蔽门方案能够得到最优的站台候车环境,但会使隧道内的温度有较大的升高,且投资较大;在投资较小的3种方案中,混合回/排风方案的效果最佳,对该方案造成的站台上气流速度分布不均匀的情况提出了相应的改善措施,并对数值模拟方法在地铁车站环控系统设计中的应用进行了探讨。 相似文献
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