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.

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.

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.

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.

Modeling and Optimal Design of a Short Primary Double-Sided Linear Induction Motor Considering Both Transverse and Longitudinal End Effects Using Improved Differential Evolution

Wang Hanming,Zhao Jinghong,Guo Guoqiang,Chen Hansi,Xiong Yiyong,Yan Sinian 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Due to its simple structure, the linear induction motor provides a linear driving force without any intermediate conversion devices. Linear induction motors are gradually used in various applications, including rail transit and the national defense industry. However, linear induction motors are affected by the end-effect phenomenon and suffer from problems such as low efficiencies and low power factors. In this paper, to optimize the performance of short primary double-sided linear induction motors (SP-DLIMs), first, a new analytical model is established based on an equivalent circuit considering both transverse and longitudinal end effects. Second, to analyze the impact of main parameters on the output characteristics of SP-DLIMs, a simple iterative design method (IDM) is presented. Third, a multi-objective optimal design method is proposed to optimize the efficiency, power factor and tooth weight of SP-DLIMs, with proposed design constraints and four different optimization problems. Moreover, an improved differential evolutionary (IDE) algorithm is proposed to optimize the design. A comparison of the results proved that the IDE yielded a competitive performance to those of other advanced heuristic algorithms. Finally, a three-dimensional time-stepping finite-element method was utilized to verify the validity of the optimization results.

V-Shaped Tin Oxide Nanostructures Featuring a Broad Photocurrent Signal: An Effective Visible-Light-Driven Photocatalyst

Wang, Geng,Lu, Wu,Li, Jinghong,Choi, Jiyoung,Jeong, Yeonseok,Choi, Sung-Yool,Park, Jong-Bong,Ryu, Min Ki,Lee, Kwangyeol WILEY-VCH Verlag 2006 Small Vol.2 No.12

<B>Graphic Abstract</B> <P>A visible difference: SnO<SUB>2</SUB> nanorods and V-shaped bipods with small diameters (<5 nm; see TEM image), high crystallinity, and good solubility in organic solvents have been synthesized. The bipods have high structural stability and a photocatalytic activity driven by visible rather than UV light. Electrodes based on the bipods have unique photoelectrochemical and electronic properties. <img src='wiley_img/16136810-2006-2-12-SMLL200600216-content.gif' alt='wiley_img/16136810-2006-2-12-SMLL200600216-content'> </P>

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.

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.

Mathematical programming model of process plant safety layout using the equipment vulnerability index

Liping Guo,Zhirong Wang,Pinkun Guo,Jinghong Wang,Dan Zhao 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.4

Safety is the focus of attention in plant layout problems. Previous studies have often expressed safety as a cost of risk, that is, the cost of property losses that may occur in an accident. In this paper, the influence of uncertainty on the equipment vulnerability is quantitatively considered and a more reliable process plant layout is proposed. The equipment vulnerability index is used to evaluate the vulnerability level of the target equipment in case of an accident, which is applied to propose a mixed-integer nonlinear optimized process plant layout to minimize domino risk. In addition, a decision matrix is applied to determine whether the risk level of the optimized layout of the target equipment is acceptable. Damage probability and vulnerability are the basic inputs of this matrix. The proposed method was applied to a coal-water slurry gasification process and the results show that the layout obtained by the proposed model has better practical value than the current layout, reducing the domino risk by 53.2%. Meanwhile, the model can be used to identify critical equipment and select targeted safety measures during the production stage.

MicroRNA-152-5p inhibits proliferation and migration and promotes apoptosis by regulating expression of Smad3 in human keloid fibroblasts

( Qianqian Pang ),( Yuming Wang ),( Mingyuan Xu ),( Jiachao Xu ),( Shengquan Xu ),( Yichen Shen ),( Jinghong Xu ),( Rui Lei ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.3

Keloids are the most common pathological form of trauma healing, with features that seriously affect appearance and body function, are difficult to treat and have a high recurrence rate. Emerging evidence suggests that miRNAs are involved in a variety of pathological processes and play an important role in the process of fibrosis. In this study, we investigated the function and regulatory network of miR-152-5p in keloids. The miRNA miR-152-5p is frequently downregulated in keloid tissue and primary cells compared to normal skin tissue and fibroblasts. In addition, the downregulation of miR-152-5p is significantly associated with the proliferation, migration and apoptosis of keloid cells. Overexpression of miR-152-5p significantly inhibits the progression of fibrosis in keloids. Smad3 is a direct target of miR-152-5p, and knockdown of Smad3 also inhibits fibrosis progression, consistent with the overexpression of miR-152-5p. The interaction between miR-152-5p and Smad3 occurs through the Erk1/2 and Akt pathways and regulates collagen3 production. In summary, our study demonstrates that miR-152-5p/Smad3 regulatory pathways involved in fibrotic progression may be a potential therapeutic target of keloids. [BMB Reports 2019; 52(3): 202-207]