Lijing Gao

Bio: Lijing Gao is an academic researcher from Chiba Institute of Science. The author has contributed to research in topics: Urban climate & Urban ecosystem. The author has an hindex of 4, co-authored 5 publications receiving 51 citations.

Passenger Ship Evacuation Simulation and Validation by Experimental Data Sets

Abstract: Due to the rapid expansion of cruise travel market as well as in light of the great loss caused by several maritime disasters, passenger ship evacuation in case of emergency has received increasing attention recently. For safety reasons, IMO has introduced a series of guidelines for undertaking full-scale evacuation analysis and certification of large passenger ships in the design stage. In this paper, an agent-based microscopic evacuation model--CityFlow-M has been introduced by a passenger ship evacuation case, and then validated using data sets from a semi-unannounced assembly trail at sea, which consists of passenger response times, starting locations, ending areas as well as the arrival times in the assembling stations. The results predicted from CityFlow-M for this case were presented and compared with the experimental data, which shows CityFlow-M is eligible of simulating the assembling process in the passenger ship.

Downward flame spread over extruded polystyrene: Effects of sample thickness, pressure, and sidewalls

Abstract: An experimental study on the characteristics of downward flame spread of extruded polystyrene (XPS) is presented. The parameters investigated include average mass loss rate per unit of thickness ( $$ \dot{m}^{'} $$ ), average flame height (H f), average flame spread rate (v f), and mass growth rate ( $$ \dot{m}_{1} $$ ) of molten XPS. The effects of sample thickness (d), sidewalls and atmospheric pressure (p), and the combined effects of these factors on the flame spread are studied. The larger sample thickness corresponds to larger $$ \dot{m}^{'} $$ and higher flame upon most occasions. As d rises, v f and $$ \dot{m}_{1} $$ increase under all conditions; v f and d follow the equation: $$ {\text{v}}_{\text f} = A ( 1- {\text{exp(}} - {\text{Cd))}} $$ . The dimensionless heat release rate: $$ \dot{Q}^{*} \propto { \exp }( - 0. 3d) $$ . $$ \dot{m}^{'} $$ , v f , and $$ \dot{m}_{1} $$ obtained without sidewalls are higher than those with sidewalls. $$ \dot{m}^{'} $$ , v f, and H f obtained on the plain (p = 100.8 kPa) are larger than those obtained on the plateau (p = 65.5 kPa). $$ \dot{m}_{1} $$ obtained on the plain is lower than that on the plateau. In most cases without sidewalls, $$ \dot{m} \propto p^{{\text n_{0}} } $$ , where 1.9 < n 0 < 2, and $$ H_{\text f} = a + \mu p^{{\text n_{0} }} $$ . H f obtained in the cases without sidewalls is larger than that with sidewalls when the sample thickness is small, while the opposite is true for thicker samples. When sidewalls are absent, on the plain, with a rise in thickness, the increase of v f is significant for thin samples while the variation is not considerable for thick samples; on the plateau, this increase is significant for all thicknesses tested. The experimental results agree well with the theoretical analysis.

Statistical Analysis on the Temporal-spatial Characteristics of Urban Fires Under Typical Urbanization Features

Abstract: The accelerating process of urbanization has brought on rapid development of urban scale, building structure, human activities and social environment, etc. Such process has undoubtedly enriched people's lives, but meanwhile, the urban fire situation has also attracted more and more attention. One important reason is that in urban areas the major fires have become much more frequency than ever before and the economic damage as well as the casualties caused by urban fires is also much huger. In this paper, based on the original fire data recorded by fire fighting departments, the urban fire distribution characteristics on temporal and spatial scales of some typical Chinese cities which present different urbanization features are analyzed. Besides, some major causes of urban fires occurrence are illustrated. The results of this paper are hoped to provide some scientific supports for the fire planning in Chinese cities.

Effect of the Ratio of the Branch Inflow to the Total Inflow on Evacuation Efficiency of Pedestrians Merging at T-junctions

Abstract: The merging of pedestrian streams is a common phenomenon in pedestrian traffic and evacuation. However it is prone to stampede and can cause immense human and economic damage because of the unreasonable merging strategy. This paper establishes a bidirectional pedestrian flow merging model based on social force model to study the effect of the ratio of the branch inflow to the total inflow on evacuation efficiency of pedestrian merging at a T-junction. The moving characteristics of pedestrian, pedestrian average speed and maximum value of density in different ratios were acquired. The most favorable ratio for evacuation was obtained by the thorough analysis. The results of this work can provide some references for controlling the merging of pedestrian streams at T-junctions during evacuation, and is contribute to propose some related controls and optimization measures to ease the congestion causing by merging, thereby increasing the evacuation efficiency.

Reliability Analysis of Occupant Safety Evacuation in Public Assembly Occupancies

Abstract: The evaluation of the failure probability and safety level of occupant evacuation is of extreme importance. The safety level of occupant evacuation is expressed by the margin of escape time. Three traditional methods for solving the reliability index are introduced and an optimization method is proposed in this study. Comparisons between the optimization method and the traditional methods are carried out. Since occupant evacuation is affected by various random parameters, it is necessary to analyze the importance of each variable in comparison with the others in occupant safety evacuation. A methodology is presented to classify the significant and insignificant random variables using sensitivity analysis. Finally, the successful application in a case study suggests that these methodologies are suitable and reliable for the reliability analysis of occupant safety evacuation in public assembly occupancies.

Quantitative Human Error Assessment during Abandon Ship Procedures in Maritime Transportation

Abstract: Human error prediction is always onerous work in the maritime domain since it is very difficult to obtain empirical data. One accepted method, Success Likelihood Index Method (SLIM), is utilized to assess human error as data is very scarce in the marine industry. The SLIM provides a quick tool to predict human error and evaluate human error probability (HEP) that occurs during the completion of a specific task. The weakness of the method is the subjectivity in the process of experts’ judgments causing difficulties in ensuring consistency. To remedy this gap, this paper proposes a fuzzy based SLIM technique which provides more accurate estimation during human error quantification. In the proposed approach, while the SLIM is utilized to estimate HEP, the fuzzy sets deal with the vagueness of expert judgments and expression in decision-making during the weighting process of performance shaping factors (PSF). To illustrate the proposed approach, the abandon ship procedure in marine transportation has been selected since the evacuation of the ship is critical to prevent the loss of life in the case of emergency. The outcomes of the paper can be utilized by ship owners, safety managers as well as ship management companies to minimize the likelihood of human error occurring within a specific task and to enhance overall levels of safety on-board a ship in the marine environment.

A State-of-the-Art Review on Empirical Data Collection for External Governed Pedestrians Complex Movement

Abstract: Complex movement patterns of pedestrian traffic, ranging from unidirectional to multidirectional flows, are frequently observed in major public infrastructure such as transport hubs. These multidirectional movements can result in increased number of conflicts, thereby influencing the mobility and safety of pedestrian facilities. Therefore, empirical data collection on pedestrians’ complex movement has been on the rise in the past two decades. Although there are several reviews of mathematical simulation models for pedestrian traffic in the existing literature, a detailed review examining the challenges and opportunities on empirical studies on the pedestrians complex movements is limited in the literature. The overall aim of this study is to present a systematic review on the empirical data collection for uni- and multidirectional crowd complex movements. We first categorized the complex movements of pedestrian crowd into two general categories, namely, external governed movements and internal driven movements based on the interactions with the infrastructure and among pedestrians, respectively. Further, considering the hierarchy of movement complexity, we decomposed the externally governed movements of pedestrian traffic into several unique movement patterns including straight line, turning, egress and ingress, opposing, weaving, merging, diverging, and random flows. Analysis of the literature showed that empirical data were highly rich in straight line and egress flow while medium rich in turning, merging, weaving, and opposing flows, but poor in ingress, diverging, and random flows. We put emphasis on the need for the future global collaborative efforts on data sharing for the complex crowd movements.

International principles of disaster risk reduction informing NGOs strategies for community based DRR mainstreaming: The Bangladesh context

Abstract: Global indexes rank Bangladesh as the 5th most disaster-prone country in the world with immense loss of life and property. In this frightening narrative of death and damage, rural people are often the most vulnerable with limited access to infrastructure (e.g. information, governance, education, and clean water) leaving them unable to cope with the effects of a disaster. More than 2,500 registered Non-Government Organizations (NGOs) are delivering numerous community level programs in Bangladesh. However, a majority of these NGOs are non-Disaster Risk Reduction (non-DRR) in their core business lacking the expertise and resources to implement programs that directly impact DRR. This paper seeks to propose a practice issues for NGOs in Bangladesh looking to strengthen their community-based DRR mainstreaming initiatives. The researchers conducted a comprehensive review of published documents around the principles that guide international disaster risk reduction globally alongside a review of international best practices for NGO’s in mainstreaming disaster risk reduction. The findings of the study reveal a need for a multi-stakeholders’ involvement in line with global best practices aimed at reducing disaster risk. The International Decade for Disaster Risk Reduction (1990-1999), Hyogo Framework for Action (2005-2015), and Sendai Framework for Disaster Risk Reduction (2015–2030) emphasized the active involvement of all necessary parties from Non-government organizations (NGOs) to government agencies and community groups in coming together to achieve mainstream disaster risk reduction. Furthermore, NGOs have the opportunity to build up the communities more resilient by including DRR principles and practices within their regular relief and development programs.

Cruise ships like buildings: Wayfinding solutions to improve emergency evacuation

Abstract: This research aims at demonstrating that wayfinding solutions can improve the effectiveness of the evacuation processes in complex architectural spaces such as those of cruise ships. We investigated the behaviours of passengers in maritime disaster to figure out whether people act similarly during buildings egress and ships evacuation. Data were collected through questionnaires administered in 2015 to passengers boarding various cruise ships at the port of Ancona (Italy), and through the analysis of real footage of the evacuation of the Costa Concordia. The open source software Fire Dynamics Simulator with Evacuation (FDS+EVAC), used in building egress analyses, was adapted to include these behavioural and event information such as familiarity with ship layout, ship rotation and lifeboats boarding. Simulation results on the case study confirmed similarities between ships and buildings evacuations, underlining the effectiveness of wayfinding solutions to improve passengers’ evacuation flows and routes selection. This study also demonstrated that computer simulation could benefit the ship design process, the preparation of safety guidelines, and the crewmembers during naval emergency management training.

How fire safety management attended during the urbanization process in China

Abstract: This paper examines how the performance of fire safety management is attended during the dramatic urbanization development process in China. Correlation and regression analysis methods are used to investigate the interrelationship between fire safety management performance and urbanization development. Three indicators are selected to measure the fire safety management performance, and seventeen indicators are used to measure urbanization development. The data used are collected from 31 provinces in China during 2005–2014. The analysis is conducted at both national and regional levels. The results show that fire safety management has not been well addressed in China although the country has made great progress in its urbanization development. The key attributes to the poor performance of fire safety management include the growth of urban population density, the increase of built-up urban areas, and the lack of fire safety education investment. There are also significant variations between different regions in addressing fire safety management, and the reasons contributing to the differences have been discussed. The findings suggest that tailor-made measures should be implemented in different regions in order to improve the performance of fire safety management throughout the country.