Boni Su

Population evacuation analysis: considering dynamic population vulnerability distribution and disaster information dissemination

Knowing the dynamic population vulnerability distribution and having an efficient information dissemination of disaster warnings play a very important role in the developing of a population evacuation strategy. In this paper, the evacuation of populations in a densely populated area of Beijing was studied with consideration of the spatio-temporal population vulnerability distribution and different methods of disaster information dissemination. Firstly, the population vulnerability distribution was obtained based on the population density, with consideration for dynamic population distribution, building heights, building types and population characteristics. Secondly, a disaster information dissemination model that utilizes sound trucks was developed, and an improved algorithm for finding the optimal route for the sound trucks was established. Thirdly, we ran 81 evacuation simulations that included different variables such as time periods, number of sound trucks, speeds of trucks and sound-spread radius. These were performed based on the dynamic population vulnerability distribution and the developed model. Through these simulations, the rates of population congestion in an evacuation area were understood, and an optimized evacuation plan was obtained and analyzed. The process and the results that were obtained are essential for improving the efficiency of evacuations, which should considerably reduce the possibility injury, deaths and other losses in a disaster.

Information dissemination analysis of different media towards the application for disaster pre-warning.

Knowing the information dissemination mechanisms of different media and having an efficient information dissemination plan for disaster pre-warning plays a very important role in reducing losses and ensuring the safety of human beings. In this paper we established models of information dissemination for six typical information media, including short message service (SMS), microblogs, news portals, cell phones, television, and oral communication. Then, the information dissemination capability of each medium concerning individuals of different ages, genders, and residential areas was simulated, and the dissemination characteristics were studied. Finally, radar graphs were used to illustrate comprehensive assessments of the six media; these graphs show directly the information dissemination characteristics of all media. The models and the results are essential for improving the efficiency of information dissemination for the purpose of disaster pre-warning and for formulating emergency plans which help to reduce the possibility of injuries, deaths and other losses in a disaster.

Integrated simulation method for waterlogging and traffic congestion under urban rainstorms

Heavy rainstorms are increasingly frequent events in urban areas. Urban rainstorms lead to road waterlogging and low visibility, which affect drivers’ behavior and can thus cause traffic congestion and potential accidents. It is important to study the mechanisms of waterlogging and traffic congestion caused by rainstorms to more effectively predict them and reduce losses. In this paper, an integrated simulation method to analyze the influence of urban rainstorms on waterlogging and traffic congestion was developed. Firstly, waterlogging simulation was conducted to predict the spatiotemporal distribution of water depth on roads based on an urban storm water model. Secondly, psychological questionnaires were distributed to study the drivers’ behavior during a rainstorm. Based on the psychological questionnaires’ results, the vehicles’ speed was estimated under different water depth and visibility conditions. Finally, a microscopic traffic simulation was carried out to predict the traffic condition using the results of the previous two parts. Case studies were conducted on a simplified road model. The effects of different parameters on waterlogging and traffic congestion were analyzed. Then the method was applied to an actual urban area in Beijing, and a detailed waterlogging situation and traffic situation were obtained. Alternate future scenarios of adding drains to mitigate waterlogging and traffic congestion during heavy rainstorms were simulated, and the method’s potential to assist in decision making for urban drainage system design was shown. The integrated simulation method is helpful for early warning and risk management of urban rainstorms on waterlogging and traffic congestion.

A human behavior integrated hierarchical model of airborne disease transmission in a large city

Abstract Epidemics of infectious diseases such as SARS, H1N1, and MERS threaten public health, particularly in large cities such as Hong Kong. We constructed a human behavior integrated hierarchical (HiHi) model based on the SIR (Susceptible, Infectious, and Recovered) model, the Wells-Riley equation, and population movement considering both spatial and temporal dimensions. The model considers more than 7 million people, 3 million indoor environments, and 2566 public transport routes in Hong Kong. Smallpox, which could be spread through airborne routes, is studied as an example. The simulation is based on peoples daily commutes and indoor human behaviors, which were summarized by mathematical patterns. We found that 59.6%, 18.1%, and 13.4% of patients become infected in their homes, offices, and schools, respectively. If both work stoppage and school closure measures are taken when the number of infected people is greater than 1000, an infectious disease will be effectively controlled after 2 months. The peak number of infected people will be reduced by 25% compared to taking no action, and the time of peak infections will be delayed by about 40 days if 90% of the infected people go to hospital during the infectious period. When ventilation rates in indoor environments increase to five times their default settings, smallpox will be naturally controlled. Residents of Kowloon and the north part of Hong Kong Island have a high risk of infection from airborne infectious diseases. Our HiHi model reduces the calculation time for infection rates to an acceptable level while preserving accuracy.

Analysis of Different Information Dissemination Ways for Disaster Prewarning: A Case Study of Beijing

Knowing the mechanisms of different information dissemination ways and having an efficient information dissemination of disaster prewarning plays a very important role in reducing the loss and ensuring the safety of disaster carrier. In this paper, first, the transmission characteristics of different information media are analyzed. Second, the mathematical models of information dissemination are established for three typical information media including television, telephone, and email. Finally, the information dissemination capability of each medium considering different ages, genders, and residential areas is simulated and the characteristic of each medium is studied. The models and the results are essential for improving the efficiency of information dissemination and making the emergency plan, which should considerably reduce the possibility injury, deaths, and other losses in a disaster.

Analysis of Road Vulnerability for Population Evacuation Using Complex Network

Population evacuation in an area with high population density is a very serious problem which should be paid more attention. Knowing the road vulnerability for population evacuation and having efficient reconstruction plans of roads, buildings and emergency shelters play a very important role in emergency response. In this paper, a complex network was used to analyze the road vulnerability for population evacuation in an objective way instead of the traditional subjective methods like the expert evaluation approach. Through the data analysis, road-load vulnerability, accessibility and safe distance to emergency shelter of each road and intersection in population evacuation are studied in detail. Furthermore, the improvement plans of each road, intersection and emergency shelter are put forward. The process and the results that were obtained are essential for improving the efficiency of evacuations and reducing the potential risk in population evacuation, which should considerably reduce the possible injury, deaths and other losses in disasters.