论文标题

人群模拟模型中使用近似贝叶斯计算的参数校准

Parameter Calibration in Crowd Simulation Models using Approximate Bayesian Computation

论文作者

Bode, Nikolai

论文摘要

行人人群的仿真模型是研究和行业中无处不在的工具。至关重要的是,这些模型的参数经过仔细校准,最终比较竞争模型以确定哪种模型最适合特定目的是很有趣的。在这项贡献中,我证明了在其他科学领域已经很流行的工具的近似贝叶斯计算(ABC)如何在行人动力环境中用于模型拟合和模型选择。我将两种不同的型号用于行人动力学,以通过瓶颈向一个方向传递的人群进行数据。一个模型描述了连续空间的运动,另一个模型是一个蜂窝自动机,因此描述了离散空间中的运动。此外,我使用两个指标将模型与数据进行比较。第一个是基于出口时间,第二个基于瓶颈前行人的速度。我的结果表明,虽然模型拟合成功,但在模型拟合后仍然存在一些模型参数值的不确定性。重要的是,模型拟合中度量的选择可以影响参数估计。对于出口时间度量,模型选择尚无定论,但支持基于速度度量的连续空间模型。这些发现表明,ABC是一种灵活的方法,突出了与行人动力学的模型拟合和模型选择相关的困难。 ABC需要许多模拟运行,并选择适当的指标来将数据与模拟进行比较,需要仔细注意。尽管如此,我还是建议ABC是一种有前途的工具,因为它具有多功能性且容易实现,可用于越来越多的公开可用的人群模拟器和数据集。

Simulation models for pedestrian crowds are a ubiquitous tool in research and industry. It is crucial that the parameters of these models are calibrated carefully and ultimately it will be of interest to compare competing models to decide which model is best suited for a particular purpose. In this contribution, I demonstrate how Approximate Bayesian Computation (ABC), which is already a popular tool in other areas of science, can be used for model fitting and model selection in a pedestrian dynamics context. I fit two different models for pedestrian dynamics to data on a crowd passing in one direction through a bottleneck. One model describes movement in continuous-space, the other model is a cellular automaton and thus describes movement in discrete-space. In addition, I compare models to data using two metrics. The first is based on egress times and the second on the velocity of pedestrians in front of the bottleneck. My results show that while model fitting is successful, a substantial degree of uncertainty about the value of some model parameters remains after model fitting. Importantly, the choice of metric in model fitting can influence parameter estimates. Model selection is inconclusive for the egress time metric but supports the continuous-space model for the velocity-based metric. These findings show that ABC is a flexible approach and highlight the difficulties associated with model fitting and model selection for pedestrian dynamics. ABC requires many simulation runs and choosing appropriate metrics for comparing data to simulations requires careful attention. Despite this, I suggest ABC is a promising tool, because it is versatile and easily implemented for the growing number of openly available crowd simulators and data sets.

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