Investigation of the Probability of a Safe Evacuation to Succeed in Subway Fire Emergencies Based on Bayesian Theory

Jinghong Wang,Wenyu Yan,Han Xu,Youran Zhi,Zhirong Wang,Juncheng Jiang 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.3

Emergency evacuation in subway fires is one of the hot issues in public safety. Based on Bayesian theory, a dynamic evacuation risk analysis model considering both psychological and behavioral responses of evacuees was proposed in this contribution. A subway fire scene was modeled using the Event Tree Analysis (ETA) according to the questionnaire survey at Nanjing Xinjiekou station. In this fire scenario, three control events (the fire alarm, the exhaust system and the evacuation route) were related to fire evacuation control and two control events (active escape and passive escape), which were specifically defined, were related to personnel characteristics. Subsequently, the probability of the final state of each scene was calculated by Monte Carlo simulation. Combined with the statistics of accidents and safe evacuation of subway fire cases from 1976 to 2013, the posterior probability distribution of safety evacuation was obtained after real-time dynamic updating of its precursor probability through Bayesian theory. Results show that the posterior probability of safety evacuation to succeed is around 0.8. This indicates that there is still a probability of 0.2 resulting in injury or fatalities in subway accidents even though most passengers are safely evacuated. It also suggests that utilization of 0.2 as the safety threshold would be an appropriate choice.

Photocatalytic removal of chromium(VI) and sulfite using transition metal (Cu, Fe, Zn) doped TiO2 driven by visible light: Feasibility, mechanism and kinetics

Jinghong Zhang,Dong Fu,Shu Qin Wang,Runlong Hao,Yixiao Xie 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

To cooperatively oxidize sulfite and reduce Cr(VI), this paper proposed a visible-light drivenphotocatalytic method, with using the photocatalysts of transition metals (Cu, Fe and Zn) dopedTiO2. The photocatalysts were characterized by means of XRD, BET, SEM and UV–vis. 0.5Cu-TiO2 exhibitedthe best performance, and the existing forms of Ti and Cu were Ti4+/Cu+ and/or Cu-O-Ti. Cu-dopingintroduced an energy level of Cu 3d which was useful in decreasing the band gap and increasing thevisible light utilization. Cu-doping also made the TiO2 grains well dispersed, increased the amount ofhydroxyl group, decreased the grain size and increased the specific surface area, which facilitated theadsorption process. Hydrothermal method (8 h and 180 C) favored the formation of anatase crystal. FT-IRresults revealed that most of produced Cr(III) and sulfate were adsorbed onto the catalyst. Kinetics resultssuggested that the rate constant for Cr(VI) removal was 5.05 10 3 min 1. The photo-produced electrons(e ) and holes (h+) contributed to the reduction of Cr(VI) and oxidation of sulfite, respectively; thecontinual consumption of e and h+ enhanced the separation of the h+-e pairs.

The Effects of Touch Button Size to the Operability of Touchscreen

Jinghong Xiong,Satoshi Muraki,Kiyotaka Fukumoto 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

The present study investigated the influence of button size on the operability of a touch panel screen and compared this influence between young adults and the elderly. Twenty-one young adults (age: 22.3±1.5 years) and twenty elderly people (age: 68.1±4.9 years) operated the interface of a touch panel screen with their right index finger. It displayed 0-9 numeric square buttons at 6 different size conditions (6, 8, 10, 12, 14 and 16 mm). Smaller buttons at and below 10 mm increased the operation time and error rate, and decreased the subjective overall operability. The influence of button size was greater in the elderly than in the young adults. The reaction positions were located to the right of the center of the button, which made the reaction position approach the right outline of the button, especially for smaller buttons. These results suggest that smaller buttons should be avoided in interfaces on touch panel screens, especially those used by the elderly.

The Effects of Touch Button Size to the Operability of Touchscreen

( Jinghong Xiong ),( Satoshi Muraki ),( Kiyotaka Fukumoto ) 한국감성과학회 2014 춘계학술대회 Vol.2014 No.-

The present study investigated the influence of button size on the operability of a touch panel screen and compared this influence between young adults and the elderly. Twenty-one young adults (age: 22.3±1.5 years) and twenty elderly people (age: 68.1±4.9 years) operated the interface of a touch panel screen with their right index finger. It displayed 0-9 numeric square buttons at 6 different size conditions (6, 8, 10, 12, 14 and 16 mm). Smaller buttons at and below 10 mm increased the operation time and error rate, and decreased the subjective overall operability. The influence of button size was greater in the elderly than in the young adults. The reaction positions were located to the right of the center of the button, which made the reaction position approach the right outline of the button, especially for smaller buttons. These results suggest that smaller buttons should be avoided in interfaces on touch panel screens, especially those used by the elderly.

A Data-driven Approach to Estimate the Probability of Pedestrian Flow Congestion at Transportation Bottlenecks

Jinghong Wang,Manman Chen,Wenyu Yan,Youran Zhi,Zhirong Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.1

In public gathering places, pedestrian flow congestion may happen in transportation bottlenecks. Limitations exist in the conventional judgment of congestion by considering the crowd density or the walking speed merely. In this paper, a data-driven mathematical approach based on Kernel Density Estimation (KDE) to analyze the probability of pedestrian flow congestion is proposed, which comprehensively considers the walking speed, the crowd density and the flow rate when pedestrians walk towards possible bottlenecks. With the case study of Nanjing metro station during rush hours, the advantages of non-parametric KDE compared with traditional parametric normal distribution estimation are analyzed and the optimal bandwidth for KDE is also discussed. The case study shows that the proposed method can obtain a more reliable quantitative assessment of congestion risk, as it overcomes the limitation of parametric estimation that relies on experience, and also avoids biased assessment of congestion that merely concerns single parameter of pedestrian flow. Finally, an assessment framework for dynamic congestion risk at bottlenecks is suggested. With this framework, the change of congestion situations of a monitored region can be mastered through data-driven approach, and thus the transformation of normal flowing to congestion of the crowd can be quantified through probabilistic analysis.

Carbon nanofibers supported Ru catalyst for sorbitol hydrogenolysis to glycols: Effect of calcination

Jinghong Zhou,Long Zhao,Hong Chen,Mingguang Zhang,Zhijun Sui,Xinggui Zhou 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

Carbon nanofiber (CNFs) supported Ru catalysts for sorbitol hydrogenolysis to ethylene glycol and propylene glycol were prepared by incipient wetness impregnation, calcination and reduction. The effect of calcination on catalyst properties was investigated using thermal gravimetry analysis, temperature-programmed reduction, X-ray diffraction,X-ray photoelectron spectroscopy, transmission electron microscopy and N2 physisorption. The results indicated that calcination introduced a great amount of surface oxygen-containing groups (SOCGs) onto CNF surface and induced the phase transformation of Ru species, but slightly changed the texture of Ru/CNFs. The catalytic performance in sorbitol hydrogenolysis showed that Ru/CNFs catalyst calcined at 240 oC presented the highest glycol selectivities and reasonable glycol yields. It was believed that the inhibition and confinement effect of SOCGs around Ru particles as well as the high dispersion of Ru particles was the key factor for the catalytic activity.

Fortress besieged: The female working poor in the evolution of Chinese social closure

Liu Jinghong 이화여자대학교 아시아여성학센터 2020 Asian Journal of Women's Studies(AJWS) Vol.26 No.3

China's political power has played a significant role in shaping gendered trends for the working poor, herein referred to as “in-work poverty” (IWP), which refers to people who work but whose incomes still fall below the official poverty threshold. By examining the historical development in China from pre-liberation days to the post-liberation period ending in the 1990s, this article examines how poverty has been gendered and how economic, social, and political processes of what are called “social closures” have led to this. Defined as processes of drawing boundaries, constructing identities, and building groups in order to monopolize scarce resources for one's own community, thereby excluding others from using them, the model of social closure (SC) in China has seen a transition. And, this illustrates how earlier norms of exclusion have changed, following its growing economic power, but continue to make a gendered impact on the working poor. I argue that economic conditions have determined the fate of the working poor with respect to their socioeconomic well-being. The evolution of SC reveals the limitations of employment-linked social insurance, the fragile and gradually loosening family protection network, a gendered institutional environment, and growing numbers of poor working women.

A Simulation Study on the Impact of Abandoned Trolley Cases on Pedestrian Evacuation

Dongyue Xu,Jinghong Wang,Juan Liu,Yan Wang,Juncheng Jiang 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

Many pedestrians empirically think that discarding luggage can improve evacuation efficiency, but it is unclear whether discarding luggage is an effective evacuation strategy. Previous models also oversimplified the interference of abandoned luggage on pedestrians. Hence, an extended social force model integrates pedestrian interaction with abandoned luggage like trolley cases was firstly proposed. A simulation based on a real metro station was carried out to examine the effectiveness of evacuation strategy like abandoning trolley cases at the bottleneck such as gate machine and metro carriage door, and the influence mechanism of abandoned trolley cases on pedestrians was investigated. The results show that discarding the trolley cases at the gate machine and at the metro carriage door cannot improve evacuation efficiency but increase the evacuation time by 78.7% and 14.9% at these two positions when the carrying ratio is 50%, respectively. When the occupancy rate of trolley case at the gate machine and metro carriage door is below 19% and 11%, pedestrians tend to detour the abandoned trolley cases and this behavior significantly increased the collisions between pedestrians at bottlenecks, and when the occupancy rate exceeds, they tend to push aside the trolley cases and the evacuation efficiency is further reduced.

Evacuation of Nursing Home Based on Massmotion: Effect of the Distribution of Dependent Elderly

Jia Li,Jinghong Wang,Bowei Jin,Yan Wang,Youran Zhi,Zhirong Wang 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4

As dramatically increased elderly population, China is entering a society of deep aging. Due to the decline of physical functions, the elderly move slowly and have difficulty in escape. Hence, enough attention should be paid on pedestrian crowds’ evacuation in a nursing home. This paper takes Chinese old-age care institutions as the research object. Using the Massmotion based on the social force to establish the evacuation model and setting the parameters according to the movement characteristics of the elderly, this paper studied the influence of the dependent elderly on evacuation efficiency when they are distributed to the higher floors of the nursing home in different proportions. The results show that the evacuation time is significantly prolonged with the increase of the proportion of dependent elderly, and there is a controllable critical value for the proportion of dependent elderly. Aspeed-up phenomenon is observed when the old man enters the landing from the stairway, and meanwhile, with the increase of the proportion of dependent elderly, the acceleration position is gradually advanced, while the instantaneous speed declines. The results of this study can provide references in properly arranging the distribution of elderly accommodation and safe evacuation of the aged care institutions.

Impact of Intersecting Angles on Evacuation Efficiency of Pedestrian Flows in High Volume: A Case Study in Metro Station

Manman Chen,Jinghong Wang,Youran Zhi,Jinhua Sun 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5

The intersection of pedestrian flows is a general phenomenon in daily pedestrian traffic and emergency evacuation. However, lacking of effective controls in crowed areas will result in pedestrian deceleration, stopping, and even threats to safety in evacuation. This paper focused on exploring the influence of different intersecting angles on evacuation efficiency of pedestrian flows in high volume. Through establishing a bidirectional pedestrian flow model with different intersecting angles for a busy metro station in China based on the social force model, two factors, namely the impact between pedestrians and the conflict frequency, were firstly proposed and validated as that playing major roles in influencing the evacuation efficiency during the pedestrian intersection. With the case study, it is found that the best intersecting angle is 120 degree and angles between 40 and 80 degree are unfavorable in optimizing the average crowd speed and the crowd density. The results are verified based on the comparative analysis with some existing experimental results. The outcomes of this work can offer some guidelines to control the intersection of pedestrian flows during evacuation and can make contributions to a proposal for the related, optimized design of a structure to increasing the evacuation efficiency of a dense crowd.