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... are able to use their knowledge to plan their path to the nearest evacuation area. Figure 1 provides a sketch off the implementation of a resident agent, f resident . Resident's think is composed by g find_way_out , g navigate , g find_inter and g coll_av . ...
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... city was chosen as it has suffered from several historical tsu- namis. The domain considered is 9.6 × 5.4 km 2 , in a 1 m × 1 m resolution grid, see Figure 11. An evacuation involving 57,000 persons is assumed. ...
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... standard deviation of the total number of agents evacuated after 40 min is considered as the influencing factor, in deciding the necessary number of simulations per Monte Carlo simulation, since total number of agents evacuated is one of the influential quantities. As shown in Figure 12, the standard deviation of the total number of people evacuated at 40 min converges (i.e. has negligibly low variation) for n > 400. In addition to the fore-mentioned global measure, statistical data of number of agents evacuated at each 30 s interval are com- pared as a local measure. ...
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... addition to the fore-mentioned global measure, statistical data of number of agents evacuated at each 30 s interval are com- pared as a local measure. Figure 13 shows the mean number of agents evacuated at each 30 s interval, for the two cases with n = 1000 and n = 400. As is seen, both the cases have nearly identical mean values and standard deviations. ...
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... all these cases, the 57,000 resident agents are consid- ered, while they are positioned within 20 m proximity of buildings initially. Figure 14 shows the time histories of cumulative number of agents evacuated for each of the four scenarios. As is seen, both the earthquake damages and tsunami inundation reduces the number of evacuees almost by the same amount. ...
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... effect of the tsunami inundation is mostly attributed to the inundation of a few critical bridges in the study area. Comparing the effect of manually blocking these bridges with the effect of the tsunami inundation shows similar results, see Figure 15. ...
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... estimating the perceived distance, the roads wider than the preferred width are reduced in length according to the level of preference. Figure 16 compares the ordinary day time evacuation with that of night time with and with- out the effects of earthquake and tsunami. As is seen, there is nearly 30% reduction in number of evacuees between the day and night scenarios without earthquake and tsunami effects. ...
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... results highlight the ability of the developed system to take different influ- encing factors like lighting conditions and the preference of safer roads. Figure 16. Time histories of total number of evacuated agents for day time and night time evacuations and in an ordinary day. ...
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... visitors and 18,000 residents are assumed to be participating in the festival, which takes place in a 14 km 2 rectangular area shown in Table 2. Further, it is assumed that evacuees prefer to take safer paths, as in the previous scenario. Figure 18 presents the results under the two lighting conditions considered. As seen, the low lighting conditions have significantly reduced the number of agents evacuated, compared that of an ordinary day. ...
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... additional scenario with moon lighting without the earthquake induced damages is simulated to further explore the effect of lighting conditions. As seen in Figure 18, for this specific setting, the influence of lighting conditions is significantly higher than the earthquake induced damages. ...
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... fictional setting is a 6 × 6.5 km 2 area of a coastal city in Japan, see Figure 19. 40,000 evacu- ees are considered with the properties shown in Table 3. ...
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... about 600 simulations the standard deviation has already converged this contrasts with the pedestrian only simulations where convergence was achieved after 400 simulations, see Figure 12. Figure 21 shows the mean and the standard deviation of the results of the cumula- tive number of agents evacuated with 1000 Monte Carlo simulations. ...
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... about 600 simulations the standard deviation has already converged this contrasts with the pedestrian only simulations where convergence was achieved after 400 simulations, see Figure 12. Figure 21 shows the mean and the standard deviation of the results of the cumula- tive number of agents evacuated with 1000 Monte Carlo simulations. The zoomed in box on the upper right corner shows a standard deviation of 0.42% in the throughput after 40 min, and in the lower right corner 0.29% after 25 min. ...
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... ;Aguilar et al. (2017Aguilar et al. ( , 2019). The reroute behavior due to the traffic congestion would in turn change the nearby traffic congestion level and further impact evacuees' traveling speeds; (3) pedestrians are considered to accelerate when the tsunami inundation comes closer. ...
Earthquake-induced tsunami can be very destructive involving significant loss of life. Evacuation to safety zones is regarded as one of the most effective ways to save lives from the tsunami strike due to the limited effectiveness of structural countermeasures. However, it is extremely challenging to successfully evacuate many people under the multi-hazard environment within a condensed time frame, especially under the near-field tsunami. Proper evacuation planning is crucial to support effective evacuation and reduce casualty. For effective evacuation planning, it is important to better understand the complex evacuation behavior for recommending proper response and behavior in an emergency. Also, it is important to have a clear picture of evacuation risk (e.g., measured in terms of expected casualty rate within a certain time frame) for informing policy and decision-making. Furthermore, it is important to identify effective pre-event mitigation strategies for effective risk reduction.
Important limitations exist in current research on the above aspects. Tsunami evacuation simulation using the agent-based model has been used to investigate the complex evacuation behavior; however, existing agent-based evacuation models usually neglect or simplify many important factors and/or mechanisms associated with the evacuation. The neglect or simplification would make the evacuation simulation less realistic and hence a good understanding of evacuation behavior challenging. For the quantification of tsunami evacuation risk, a systematic framework that can address complex evacuation models and uncertainty (including aleatory and epistemic uncertainties) models is needed; however, no such framework has been developed for the quantification of tsunami evacuation risk. Also, some important uncertainties such as that in the seismic damage to the bridge are usually neglected or the uncertainty quantification is simplified. In this case, it would be difficult to assess the evacuation risk accurately and provide a clear picture of the evacuation risk. For effective pre-event evacuation risk mitigation, the effectiveness of different mitigation strategies needs to be quantitatively evaluated to identify more effective strategies. However, the effectiveness of the mitigation strategy is usually evaluated more qualitatively than quantitatively. Furthermore, the evaluation is typically conducted without systematically considering various uncertainties, which makes the identified strategies not robust to uncertainties. In tsunami evacuation risk assessment and mitigation, risk evaluation using general stochastic simulation techniques (e.g., Monte Carlo simulation) typically entails significant computational challenges. Efficient algorithms are needed to alleviate such computational challenges and facilitate such tasks.
To bridge the above knowledge gaps, this research proposes a generalized framework for simulation-based tsunami evacuation risk assessment and risk-informed mitigation. The framework is built layer by layer through integrating tsunami evacuation simulation using agent-based modeling (ABM) technique, simulation-based evacuation risk assessment, sensitivity analysis of evacuation risk, and risk-informed evaluation of mitigation strategies. An improved agent-based tsunami evacuation model is developed for more realistic tsunami evacuation simulation by incorporating many of the typically neglected or simplified but important factors and/or mechanisms in the evacuation. Using the proposed agent-based evacuation model, a simulation-based framework is proposed to quantify the evacuation risk, in which various uncertainties (including aleatory and epistemic uncertainties) associated with the evacuation are explicitly considered and modeled by proper selection of probability distribution models. Sensitivity analysis of evacuation risk with respect to the epistemic uncertainty is performed, and the sensitivity information can be used to guide effective epistemic uncertainty reduction and hence for more accurate risk assessment. Also, sensitivity analysis is performed to identify critical risk factors, and the sensitivity information can be used to guide effective evacuation modeling and selection of candidate risk mitigation strategies. Risk-informed evaluation of different types of candidate mitigation strategies (including infrastructural and non-infrastructural strategies) is conducted to identify more effective strategies that are robust to uncertainties. Efficient sample-based approaches are developed to alleviate the computational challenges in evacuation risk assessment, sensitivity analysis, and risk-informed evaluation of mitigation strategies. As an illustrative example, the proposed framework is applied to tsunami evacuation risk assessment and risk-informed mitigation for the coastal community of Seaside, Oregon.
... We mean by safety-critical systems all systems in which failures may lead to catastrophic consequences, such as loss of human life, significant damage to the environment, and/or financial disasters. In such a case, multi-agent systems have been widely used to better developing [30,31], simulating [32], securing [33] and analyzing [34] of critical systems. Firstly, in [10], the main objective was to propose a formal methodology in order to ensure the correctness properties of safety and liveness of the Mail Transport System. ...
