Evaluation of the Dimensions of the Tsunami Evacuation Path for the Community of Air Tawar Barat Village, North Padang District, Padang City, Based on Geographic Information System (GIS)

Air Tawar Barat Village is located in North Padang District, Padang City which is directly adjacent to the Indian Ocean in the west, so there is a risk of a tsunami disaster. The current evacuation route, which is one of the efforts to overcome the tsunami disaster, seems to be still ineffective to use because the distance that must be covered is 3-5 km in less than 30 minutes. This study aims to determine the direction of an effective evacuation route and then make a comparison with the evacuation route that has been determined by the Government. The method used is Network Analyst. The results of this study obtained 3 alternatives to make evacuation more effective. The alternative is to make access roads around Jalan Gajah to go to P-TES in the UNP area. Alternative 2 is to make P-TES in the parking lot of the Air Tawar Health Center so that people around the river mouth can evacuate faster because they are closer. Alternative 3, the community around the North Padang Police Sector can evacuate by heading to P-TES on Jalan Polonia, Air Tawar Timur Village to stay away from the beach. The three alternatives make the evacuation time to 10 minutes by heading to 26 P-TES. In addition, the evacuation map as a result of the analysis is more effective because the route has a route that is more likely to be taken by the community compared to the government evacuation map.

Analysis of Small and Medium–Scale River Flood Risk in Case of Exceeding Control Standard Floods Using Hydraulic Model

Exceeding control standard floods pose threats to the management of small and medium–scale rivers. Taking Fuzhouhe river as an example, this paper analyzes the submerged depth, submerged area and arrival time of river flood risk in the case of exceeding control standard floods (with return period of 20, 50, 100 and 200 years) through a coupled one– and two–dimensional hydrodynamic model, draws the flood risk maps and proposes emergency plans. The simulation results of the one–dimensional model reveal that the dikes would be at risk of overflowing for different frequencies of floods, with a higher level of risk on the left bank. The results of the coupled model demonstrate that under all scenarios, the inundation area gradually increases with time until the flood peak subsides, and the larger the flood peak, the faster the inundation area increases. The maximum submerged areas are 42.73 km2, 65.95 km2, 74.86 km2 and 82.71 km2 for four frequencies of flood, respectively. The change of submerged depth under different frequency floods shows a downward–upward–downward trend and the average submerged depth of each frequency floods is about 1.4 m. The flood risk maps of different flood frequencies are created by GIS to analyze flood arrival time, submerged area and submerged depth to plan escape routes and resettlement units. The migration distances are limited within 4 km, the average migration distance is about 2 km, the vehicle evacuation time is less than 20 min, and the walking evacuation time is set to about 70 min. It is concluded that the flood risk of small and medium–scale rivers is a dynamic change process, and dynamic flood assessment, flood warning and embankment modification scheme should be further explored.

Optimising Pedestrian Flow Around Large Stadiums

This study proposes a method that combines the cellular automaton model and the differential evolution algorithm for optimising pedestrian flow around large stadiums. A miniature version of a large stadium and its surrounding areas is constructed via the cellular automaton model. Special mechanisms are applied to influence the behaviour of an agent that leaves from a certain stadium gate. The agent may be attracted to a nearby business facility and/or guided to uncongested areas. The differential evolution algorithm is then used to determine the optimal probabilities of the influencing agents for each stadium gate. The main goal is to reduce the evacuation time, and other goals such as reducing the costs for the influencing agents’ behaviours and the individual evacuation time are also considered. We found that, although they worked differently in different scenarios, the attraction and guidance of agents significantly reduced the evacuation time. The optimal evacuation time was achieved with moderate attraction to the business facilities and strong guidance to the detouring route. The results demonstrate that the proposed method can provide a goal-dependent, exit-specific strategy that is otherwise hard to acquire for optimising pedestrian flow.

Fast flow algorithm prioritizing the most time-consuming source point by using a multi-source evacuation model

In many public spaces (e.g. colleges and shopping malls), people are frequently distributed discretely, and thus, single-source evacuation, which means there’s only one point of origin, is not always a feasible solution. Hence, this paper discusses a multi-source evacuation model and algorithm, which are intended to evacuate all the people that are trapped within the minimum possible time. This study presents a fast flow algorithm to prioritize the most time-consuming source point under the constraint of route and exit capacity to reduce the evacuation time. This fast flow algorithm overcomes the deficiencies in the existing global optimization fast flow algorithm and capacity constrained route planner (CCRP) algorithm. For the fast flow algorithm, the first step is to determine the optimal solution to single-source evacuation and use the evacuation time of the most time-consuming source and exit gate set as the initial solution. The second step is to determine a multi-source evacuation solution by updating the lower limit of the current evacuation time and the exit gate set continually. The final step is to verify the effectiveness and feasibility of the algorithm through comparison.

Social Distancing with the Optimal Steps Model

With the Covid-19 pandemic, an urgent need has arisen to simulate social distancing. The Optimal Steps Model (OSM) is a pedestrian locomotion model that operationalizes an individual's need for personal space. We present new parameter values for personal space in the OSM to simulate social distancing in the pedestrian dynamics simulator Vadere. Our approach is pragmatic. We consider two use cases: in the first, we demand that a set social distance must never be violated. In the second the social distance can be violated temporarily for less than 10s. For each use case we conduct simulation studies in a typical bottleneck scenario and measure contact times, that is, violations of the social distance rule.We conduct regression analysis to assess how the parameter choice depends on the desired social distance and the corridor width. We find that evacuation time increases linearly with the width of the repulsion potential, which is an analogy to physics modeling the strength of the need for personal space. The evacuation time decreases linearly with larger corridor width. The influence of the corridor width on the evacuation time is smaller than the influence of the range of the repulsion, that is, the need for personal space. If the repulsion is too strong, we observe clogging effects. Our regression formulas enable Vadere users to conduct their own studies without understanding the intricacies of the OSM implementation and without extensive parameter adjustment.

PASSENGER RESPONSE TIME DATA- SETS FOR LARGE PASSENGER FERRIES AND CRUISE SHIPS DERIVED FROM SEA TRIALS

The paper consists of 27 figures; numerous equations and 12 notes/ references, many of which are written by the authors of this paper. Whilst this may indicate a lack of “reading around the subject” it also indicates the unique nature of the topic and that little exists at present in the public domain about this topic. Indeed the authors and the research group they represent are the main contributors to the IMOs discussions and circulars on this subject. Given that background the paper is very detailed and consists of comparisons between the evacuation times of 3 passenger ships, 2 being Ro-Pax vessels and 1 a cruise liner. On board evacuation time statistics have been gathered from significant populations enabling the authors to draw significant conclusions relating to evacuation times in the presented scenarios. The paper is therefore a useful addition to the debates on this subject which is of major relevance to the understanding of evacuation times in passenger vessels. Data and research in this area is difficult to obtain thus the authors should be congratulated for their work.

A SIMULATION-BASED METHODOLOGY FOR EVALUATING THE FACTORS ON SHIP EMERGENCY EVACUATION

There are many hazards on a ship that makes an emergency evacuation process inevitable. Providing safe and effective evacuation of passengers from ships in an emergency situation becomes critical. Handling a real ship evacuation practice is often unaffordable as modelling such an environment is very expensive and may cause severe distress to participants. As an alternative, simulation models have been used to overwhelm the issue above in recent years. Therefore, this paper proposes a novel simulation-based methodology for evaluating the effect of factors including physical as well as psychological passenger characteristics and routeing systematic on emergency evacuation process for public marine transportation. A detailed questionnaire has been conducted in this work to reflect passenger characteristics on simulation model in a more realistic manner. Also, a new routeing systematic is developed to provide an efficient evacuation procedure. As another contribution, a novel grid-based approach where the meshed discretized nodes can contain more than one passenger is proposed in simulation model for the first time. Then, a statistical analysis is included within the methodology to assess the importance level of each factor on evacuation time. The proposed methodology is applied to a real life Ro-Ro ferry. A validation protocol based on IMO regulations is conducted and confirmed the effectiveness of the suggested simulation model. The simulation of different scenario types have indicated the influencing factors in a ship emergency evacuation. According to results, passenger characteristics has been identified as the most dominant factor on evacuation performance. The highest evacuation time difference has been observed for different levels of weight attribute. Moreover, it is concluded that the consideration of load utilization balancing among evacuation systems for routeing decreases evacuation time significantly. Finally, significant evacuation time difference between grid approaches have been demonstrated.