"Last-Mile" preparation for a potential disaster

Extreme natural events, like e.g. tsunamis or earthquakes, regularly lead to catastrophes with dramatic consequences. In recent years natural disasters caused hundreds of thousands of deaths, destruction of infrastructure, disruption of economic activity and loss of billions of dollars worth of property and thus revealed considerable deficits hindering their effective management: Needs for stakeholders, decision-makers as well as for persons concerned include systematic risk identification and evaluation, a way to assess countermeasures, awareness raising and decision support systems to be employed before, during and after crisis situations. The overall goal of this study focuses on interdisciplinary integration of various scientific disciplines to contribute to a tsunami early warning information system. In comparison to most studies our focus is on high-end geometric and thematic analysis to meet the requirements of small-scale, heterogeneous and complex coastal urban systems. Data, methods and results from engineering, remote sensing and social sciences are interlinked and provide comprehensive information for disaster risk assessment, management and reduction. In detail, we combine inundation modeling, urban morphology analysis, population assessment, socio-economic analysis of the population and evacuation modeling. The interdisciplinary results eventually lead to recommendations for mitigation strategies in the fields of spatial planning or coping capacity

Design of evacuation plans for densely urbanised city centres

The high population density and tightly packed nature of some city centres make emergency planning for these urban spaces especially important, given the potential for human loss in case of disaster. Historic and recent events have made emergency service planners particularly conscious of the need for preparing evacuation plans in advance. This paper discusses a methodological approach for assisting decision-makers in designing urban evacuation plans. The approach aims at quickly and safely moving the population away from the danger zone into shelters. The plans include determining the number and location of rescue facilities, as well as the paths that people should take from their building to their assigned shelter in case of an occurrence requiring evacuation. The approach is thus of the location–allocation–routing type, through the existing streets network, and takes into account the trade-offs among different aspects of evacuation actions that inevitably come up during the planning stage. All the steps of the procedure are discussed and systematised, along with computational and practical implementation issues, in the context of a case study – the design of evacuation plans for the historical centre of an old European city

VELOS: A VR Platform for Ship-Evacuation Analysis

“Virtual Environment for Life On Ships” (VELOS) is a multi-user Virtual Reality (VR) system that aims to support designers to assess (early in the design Process) passenger and crew activities on a ship for both normal and hectic Conditions of operations and to improve ship design accordingly. This paper focuses On presenting the novel features of VELOS related to both its VR and Evacuation-specific functionalities. These features include: i) capability of multiple Users’ immersion and active participation in the evacuation process, ii) Real-time interactivity and capability for making on-the-fly alterations of environment Events and crowd-behavior parameters, iii) capability of agents and Avatars to move continuously on decks, iv) integrated framework for both the Simplified and the advanced method of analysis according to the IMO/MSC 1033 Circular, v) enrichment of the ship geometrical model with a topological model Suitable for evacuation analysis, vi) efficient interfaces for the dynamic specification and handling of the required heterogeneous input data, and vii) post Processing of the calculated agent trajectories for extracting useful information For the evacuation process. VELOS evacuation functionality is illustrated using Three evacuation test cases for a ro-ro passenger ship

Heuristic search methods and cellular automata modelling for layout design

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Spatial layout design must consider not only ease of movement for pedestrians under normal conditions, but also their safety in panic situations, such as an emergency evacuation in a theatre, stadium or hospital. Using pedestrian simulation statistics, the movement of crowds can be used to study the consequences of different spatial layouts. Previous works either create an optimal spatial arrangement or an optimal pedestrian circulation. They do not automatically optimise both problems simultaneously. Thus, the idea behind the research in this thesis is to achieve a vital architectural design goal by automatically producing an optimal spatial layout that will enable smooth pedestrian flow. The automated process developed here allows the rapid identification of layouts for large, complex, spatial layout problems. This is achieved by using Cellular Automata (CA) to model pedestrian simulation so that pedestrian flow can be explored at a microscopic level and designing a fitness function for heuristic search that maximises these pedestrian flow statistics in the CA simulation. An analysis of pedestrian flow statistics generated from feasible novel design solutions generated using the heuristic search techniques (hill climbing, simulated annealing and genetic algorithm style operators) is conducted. The statistics that are obtained from the pedestrian simulation is used to measure and analyse pedestrian flow behaviour. The analysis from the statistical results also provides the indication of the quality of the spatial layout design generated. The technique has shown promising results in finding acceptable solutions to this problem when incorporated with the pedestrian simulator when demonstrated on simulated and real-world layouts with real pedestrian data.This study was funded by the University Science of Malaysia and Kementerian Pengajian Tinggi Malaysia

"Last-Mile" preparation for a potential disaster - Interdisciplinary approach towards tsunami early warning and an evacuation information system for the coastal city of Padang, Indonesia

Extreme natural events, like e.g. tsunamis or earthquakes, regularly lead to catastrophes with dramatic consequences. In recent years natural disasters caused hundreds of thousands of deaths, destruction of infrastructure, disruption of economic activity and loss of billions of dollars worth of property and thus revealed considerable deficits hindering their effective management: Needs for stakeholders, decision-makers as well as for persons concerned include systematic risk identification and evaluation, a way to assess countermeasures, awareness raising and decision support systems to be employed before, during and after crisis situations. The overall goal of this study focuses on interdisciplinary integration of various scientific disciplines to contribute to a tsunami early warning information system. In comparison to most studies our focus is on high-end geometric and thematic analysis to meet the requirements of smallscale, heterogeneous and complex coastal urban systems. Data, methods and results from engineering, remote sensing and social sciences are interlinked and provide comprehensive information for disaster risk assessment, management and reduction. In detail, we combine inundation modeling, urban morphology analysis, population assessment, socioeconomic analysis of the population and evacuation modeling. The interdisciplinary results eventually lead to recommendations for mitigation strategies in the fields of spatial planning or coping capacity.DFG/03G0666A-

LED wristbands for cell-based crowd evacuation: an adaptive exit-choice guidance system architecture

Cell-based crowd evacuation systems provide adaptive or static exit-choice indications that favor a coordinated group dynamic, improving evacuation time and safety. While a great effort has been made to modeling its control logic by assuming an ideal communication and positioning infrastructure, the architectural dimension and the influence of pedestrian positioning uncertainty have been largely overlooked. In our previous research, a cell-based crowd evacuation system (CellEVAC) was proposed that dynamically allocates exit gates to pedestrians in a cell-based pedestrian positioning infrastructure. This system provides optimal exit-choice indications through color-based indications and a control logic module built upon an optimized discrete-choice model. Here, we investigate how location-aware technologies and wearable devices can be used for a realistic deployment of CellEVAC. We consider a simulated real evacuation scenario (Madrid Arena) and propose a system architecture for CellEVAC that includes: a controller node, a radio-controlled light-emitting diode (LED) wristband subsystem, and a cell-node network equipped with active Radio Frequency Identification (RFID) devices. These subsystems coordinate to provide control, display, and positioning capabilities. We quantitatively study the sensitivity of evacuation time and safety to uncertainty in the positioning system. Results showed that CellEVAC was operational within a limited range of positioning uncertainty. Further analyses revealed that reprogramming the control logic module through a simulation optimization process, simulating the positioning system's expected uncertainty level, improved the CellEVAC performance in scenarios with poor positioning systems.Ministerio de Economía, Industria y Competitivida

Modelling Ascending Stair Evacuation

The thesis presents a basic validation study on the use of evacuation models for the simulation of ascending stair evacuation. The validation of the evacuation models is performed against a benchmark experiment consisting of a 50-floor ascending evacuation. The aim is to find which models – depending on the input calibration effort -can provide conforming results against the benchmark experiment regarding total evacuation time and walking speeds at each floor. This is performed by selecting five evacuation models for validation, representing different types of modelling assumptions. These models are then used to simulate ascending evacuation applying default settings and modified settings. The study indicates that models under consideration are not conservative when applying their default settings but models which have the possibility to alter the reducing speed factors per floor generally give better conforming results to the experimental results. The study also shows that the models estimation of the walked distance is a crucial factor.Validation study on the use of evacuation models for simulation of long ascending stair evacuation Properties which slow down walking speed with walked vertical distance and the estimation of the distance walked are the crucial factors when evacuation models simulate evacuation in long ascending stairs. Increased urbanisation leads to the construction of more and often complex underground facilities to cope with an increasing demand of e.g. transportation facilities. In case of evacuation from such a facility, long ascending stairs may have to be travelled and it can be assumed that physical fatigue can influence the walking speed negatively and thus the total time of evacuation. There is limited information and validation available on the reliability of evacuation models in long ascending stair evacuation cases. Since these evacuation models are used for designing purposes it is a crucial topic to study. The validation study of the ascending evacuation scenario in long stairs using a full scale experiment as benchmark was performed and focused on the simulated total evacuation time and walking speed. Three different input configurations were applied to the models to find possible changes in the results in relation to the degree of user effort in the input calibration phase. The configurations were; default settings, applied reducing speed factors and a modified distribution of the initial walking speed. The evacuation models’ (EXIT89, FDS+Evac, Pathfinder, Simulex and STEPS) default settings do in general underestimate the evacuation time while with applied reducing speed factors the evacuation time is better conforming to the 50 floor benchmark experiment study. Modification of the models initial walking speed distribution does not give better corresponding results and should thus be kept default. It is the models possibility to simulate deceleration of walking speed that is an important factor and not the model type (continuous, coarse- or fine network). The validation study also indicates that the vertical distance walked should be determining for decelerating walking speed and thus indirectly fatigue, not the horizontal distance walked. Surprisingly, since it was not a factor thought of at the commencement of the study, the models’ assumptions affecting the travelled distance is one of the most settling factors. Large divergences in walked distance, where the evacuation model STEPS estimate the distance to approximately 30 % less than the benchmark experiment, shows that the calculation of walked distance should be thoroughly considered when using evacuation models for simulations as it will affect walking speed and the total evacuation time. EXIT89 and Simulex are not applicable for simulation of evacuation in long stairs since deceleration of walking speed not is available. The models, FDS+Evac, Pathfinder and STEPS, are not recommended for simulation of ascending evacuation in long stairs with default settings but with the application of reducing speed factors. They can be used for simulation of evacuation cases similar to the benchmark experiment, approximately 50 floor ascending stair evacuation, with considerable user input regarding deceleration of walking speed

Decomposition of Probability Marginals for Security Games in Abstract Networks

Given a set system $(E, \mathcal{P})$, let $\pi \in [0,1]^{\mathcal{P}}$ be a vector of requirement values on the sets and let $\rho \in [0, 1]^E$ be a vector of probability marginals with $\sum_{e \in P} \rho_e \geq \pi_P$ for all $P \in \mathcal{P}$. We study the question under which conditions the marginals $\rho$ can be decomposed into a probability distribution on the subsets of $E$ such that the resulting random set intersects each $P \in \mathcal{P}$ with probability at least $\pi_P$. Extending a result by Dahan, Amin, and Jaillet (MOR 2022) motivated by a network security game in directed acyclic graphs, we show that such a distribution exists if $\mathcal{P}$ is an abstract network and the requirements are of the form $\pi_P = 1 - \sum_{e \in P} \mu_e$ for some $\mu \in [0, 1]^E$. Our proof yields an explicit description of a feasible distribution that can be computed efficiently. As a consequence, equilibria for the security game studied by Dahan et al. can be efficiently computed even when the underlying digraph contains cycles. As a subroutine of our algorithm, we provide a combinatorial algorithm for computing shortest paths in abstract networks, answering an open question by McCormick (SODA 1996). We further show that a conservation law proposed by Dahan et al. for requirement functions in partially ordered sets can be reduced to the setting of affine requirements described above

DEVELOPMENT OF A MIXED-FLOW OPTIMIZATION SYSTEM FOR EMERGENCY EVACUATION IN URBAN NETWORKS

In most metropolitan areas, an emergency evacuation may demand a potentially large number of evacuees to use transit systems or to walk over some distance to access their passenger cars. In the process of approaching designated pick-up points for evacuation, the massive number of pedestrians often incurs tremendous burden to vehicles in the roadway network. Hence, one critical issue in a multi-modal evacuation planning is the effective coordination of the vehicle and pedestrian flows by considering their complex interactions. The purpose of this research is to develop an integrated system that is capable of generating the optimal evacuation plan and reflecting the real-world network traffic conditions caused by the conflicts of these two types of flows. The first part of this research is an integer programming model designed to optimize the control plans for massive mixed pedestrian-vehicle flows within the evacuation zone. The proposed model, integrating the pedestrian and vehicle networks, can effectively account for their potential conflicts during the evacuation. The model can generate the optimal routing strategies to guide evacuees moving toward either their pick-up locations or parking areas and can also produce a responsive plan to accommodate the massive pedestrian movements. The second part of this research is a mixed-flow simulation tool that can capture the conflicts between pedestrians, between vehicles, and between pedestrians and vehicles in an evacuation network. The core logic of this simulation model is the Mixed-Cellular Automata (MCA) concept, which, with some embedded components, offers a realistic mechanism to reflect the competing and conflicting interactions between vehicle and pedestrian flows. This study is expected to yield the following contributions * Design of an effective framework for planning a multi-modal evacuation within metropolitan areas; * Development of an integrated mixed-flow optimization model that can overcome various modeling and computing difficulties in capturing the mixed-flow dynamics in urban network evacuation; * Construction and calibration of a new mixed-flow simulation model, based on the Cellular Automaton concept, to reflect various conflicting patterns between vehicle and pedestrian flows in an evacuation network