scholarly journals Modeling and Simulation of Exit Selection Behavior in Pedestrian Evacuation Based on Information Perception and Transmission

2021 ◽  
Vol 13 (23) ◽  
pp. 13194
Author(s):  
Mengting Liu ◽  
Wei Zhu ◽  
Yafei Wang ◽  
Jianchun Zheng

This paper aims to present an improved evacuation model, which is capable of simulating individual exit selection behavior based on the acquisition and processing of information, especially in dangerous and unfamiliar environments. Firstly, an evacuation model was improved by the introduction of a floor field of gas concentration and an exit selection model, considering the congestion avoidance and danger avoidance behavior. Secondly, the process of information perception and transmission was studied and introduced into the model with a set of rules. Finally, real experiments in a simple double-exit room were conducted for model validation and parameter setting, and simulation experiments in scenarios with an unknown hazard or unknown exits were conducted to confirm the necessity and rationality of introducing information perception and transmission. The simulation results show that, with the increase in perception distance or trust extent, the pedestrian safety increases. The critical values of perception distance or trust extent, below which some people cannot acquire any new information, vary depending on the pedestrian density. When the density is high, the influence of perception distance or trust extent reduces, and the probability of reselecting an exit increases, which causes the safety of pedestrians to decrease.

2014 ◽  
Vol 505-506 ◽  
pp. 1172-1178
Author(s):  
Sheng Nan Li ◽  
Xin Gang Li

The behavior of pedestrians around the corner of a room or a corridor is one of the most important features in pedestrian evacuating dynamics. In order to study this in detail, an existing potential field model is modified to capture the pedestrian dynamic around corner by introducing a local density parameter. The local density parameter of a cell is defined as the pedestrian occupancy of the surrounding eight neighbors. Simulations are carried out to study pedestrian evacuation in rooms with corners formed by internal obstacles and walls. The simulation results show that the new model can reproduce the empirical pedestrian dynamics around corner. Pedestrians prefer to walk to lower pedestrian density area although the route may be a little longer. It is also shown that the total evacuation time could be reduced for the evacuation corridor is fully utilized.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3197 ◽  
Author(s):  
Ke Liu ◽  
Wenqi Wu ◽  
Zhijia Wu ◽  
Lei He ◽  
Kanghua Tang

Intentional spoofing interference can cause damage to the navigation terminal and threaten the security of a global navigation satellite system (GNSS). For spoofing interference, an anti-spoofing algorithm based on pseudorange differences for a single receiver is proposed, which can be used to detect simplistic and intermediate spoofing attacks, as well as meaconing attacks. Double-difference models using the pseudorange of two adjacent epochs are established followed by the application of Taylor expansion to the position relationship between the satellite and the receiver (or the spoofer). The authenticity of the signal can be verified by comparing the results of the proposed spoofing detection algorithm with the traditional least squares method. The results will differ when spoofing is present. The parameter setting of the proposed algorithm is introduced. The algorithm has the advantage of both simplicity and efficiency and needs only a single receiver and pseudorange data. A NovAtel receiver is adopted for the actual experiments. The Texas spoofing test battery (TEXBAT), as well as two other simulation experiments are used to verify the performance of the algorithm. The simulation results validate the feasibility and effectiveness of the algorithm.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Qian Xiao ◽  
Jiayang Li

Crowd evacuation under emergency is an important task of world public security research and practice. In order to describe the microemotional contagion of evacuation individuals, a cellular automata-based evacuation model of emotional contagion crowd based on the classical SIS model of infectious diseases is proposed in this paper. Firstly, the state of evacuation individual is defined as “emotional susceptible” and “emotional infective.” Then, a dynamic model considering emotional contagion is established with cellular automata. Based on the models of static floor field and dynamic floor field, the emotion updating rules and state updating rules are constructed. The influence of perception domain radius on pedestrian evacuation process is analyzed through experiments. The conclusion can provide evacuation guidance for evacuation individuals. The comparative experiment results show that the improved model can reflect the movement characteristics of evacuation individuals effectively. The evacuation efficiency of the whole system is also effectively improved due to the consideration of emotional contagion and evacuation strategy.


2021 ◽  
Author(s):  
Yat Sing Pang ◽  
Martin Kaminski ◽  
Anna Novelli ◽  
Philip Carlsson ◽  
Ismail-Hakki Acir ◽  
...  

<p>Limonene is the fourth-most abundant monoterpene in the atmosphere, which upon oxidation leads to the formation of secondary organic aerosol (SOA) and thereby influences climate and air quality.</p><p>In this study, the oxidation of limonene by OH at different atmospherically relevant NO and HO<sub>2</sub> levels (NO: 0.1 – 10 ppb; HO<sub>2</sub>: 20 ppt) was investigated in simulation experiments in the SAPHIR chamber at Forschungszentrum Jülich. The analysis focuses on comparing measured radical concentrations (RO<sub>2</sub>, HO<sub>2</sub>, OH) and OH reactivity (k<sub>OH</sub>) with modeled values calculated using the Master Chemical Mechanism (MCM) version 3.3.1.</p><p>At high and medium NO concentrations, RO<sub>2</sub> is expected to quickly react with NO. An HO<sub>2</sub> radical is produced during the process that can be converted back to an OH radical by another reaction with NO. Consistently, for experiments conducted at medium NO levels (~0.5 ppb, RO<sub>2</sub> lifetime ~10 s), simulated RO<sub>2</sub>, HO<sub>2</sub>, and OH agree with observations within the measurement uncertainties, if the OH reactivity of oxidation products is correctly described.</p><p>At lower NO concentrations, the regeneration of HO<sub>2</sub> in the RO<sub>2</sub> + NO reaction is slow and the reaction of RO<sub>2</sub> with HO<sub>2</sub> gains importance in forming peroxides. However, simulation results show a large discrepancy between calculated radical concentrations and measurements at low NO levels (<0.1 ppb, RO<sub>2</sub> lifetime ~ 100 s). Simulated RO<sub>2</sub> concentrations are found to be overestimated by a factor of three; simulated HO<sub>2</sub> concentrations are underestimated by 50 %; simulated OH concentrations are underestimated by about 35%, even if k<sub>OH</sub> is correctly described. This suggests that there could be additional RO<sub>2</sub> reaction pathways that regenerate HO<sub>2</sub> and OH radicals become important, but they are not taken into account in the MCM model.</p>


MAUSAM ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 221-230
Author(s):  
O. P. SINGH ◽  
K. RUPA KUMAR ◽  
P. K. MISHRA ◽  
K. KRISHNA KUMAR ◽  
S. K. PATWARDHAN

Lkkj & bl 'kks/k&i= esa HkweaMyh; tyok;q ifjorZu ds ifj.kkeLo:i 'krkCnh ds e/; ¼2041&60½ ds nkSjku ,f’k;kbZ xzh"edkyhu ekulwu ds fof’k"V y{k.kksa dk iwokZuqeku djus ds mÌs’; ls vuqdj.k iz;ksxksa ds ifj.kke izLrqr fd, x, gSaA blds fy, gSMys tyok;q iwokZuqeku vkSj vuqla/kku dsUnz] ;w- ds- dk {ks=h; tyok;q ekWMy gSM vkj- ,e- 2 dk mi;ksx fd;k x;k gSA ,f’k;kbZ {ks= ds fy, 20 o"kksZa dh vof/k ds nks vuqdj.k iz;ksx fd, x, gSa uker% igyk] 1990 Lrjksa ds vuq:i xzhu gkml xSl lkanz.k dh fu/kkZfjr ek=k] ftls dUVªksy ¼lh- Vh- ,y-½ iz;ksx dgk x;k gS vkSj nwljk 1990 ls ysdj 2041&60 rd ds fy, xzhu gkml xSl lkanz.k ds okf"kZd feJ.k esa 1 izfr’kr dh o`f) lesr ftls vkxs xzhu gkml xSl ¼th- ,p- th-½ iz;ksx dgk x;k gSA xzhu gkml xSl lkanz.k esa okf"kZd feJ.k esa 1 izfr’kr dh o`f) tyok;q ifjorZu ds var% ljdkjh iSuy vkbZ- ih- lh- lh- }kjk rS;kj dh xbZ ;kstuk ls yh xbZ gSA bu iz;ksxksa ls 'krkCnh ds e/; ds nkSjku ,f’k;kbZ xzh"edkyhu ekulwu esa ik, tkus okys fof’k"V y{k.kksa esa gksus okys dqN ifjorZuksa dk irk pyk gS ftudk c<+s gq, ekuotfur mRltZdksa ds dkj.k gksuk LokHkkfor gSA lewph ekulwu _rq ds nkSjku Hkkjrh; {ks= ij fuEu {kksHk eaMy ¼850 gSDVkikLdy½ esa ekulwu nzks.kh ¼,e- Vh- ½ dk mRrj dh vksj lkekU; :i ls c<+uk lcls vf/kd egRoiw.kZ ifjorZu izrhr gksrk gSA vuqdj.k ifj.kkeksa ls ekulwu _rq ds nkSjku vjc lkxj esa leqnz Lrj nkc ¼,l- ,y- ih-½ esa yxHkx 1&2 gS- ik- dh o`f) dk irk pyk gS ftlds ifj.kkeLo:i fuEu {kksHk eaMy esa vlkekU; izfrpØokr gksrs gSaA bldk vFkZ ;g gqvk fd fuEu Lrjh; tsV ¼,y- ,y- ts-½ vkSj vjc lkxj esa ekulwu dh /kkjk det+ksj iM+ tkrh gSA ;g ekWMy m".krj leqnz lrg dh fLFkfr;ksa esa fgan egklkxj ds mRrj esa ekulwuh pØokrh; fo{kksHkksa dh vko`fr esa deh dks vuqdfjr djrk gS tks gky gh ds n’kdksa esa ekulwu ds vonkcksa dh vko`fr esa deh dh izo`fr;ksa ds vuq:i ikbZ xbZ gSA bu iz;ksxksa ls ;g irk pyrk gS fd ikfdLrku vkSj mlds lehiorhZ mRrjh if’peh Hkkjr ds Åij Å"ek fuEunkc rhoz gks ldrk gS vkSj ekulwu _rq           ds nkSjku FkksM+k iwoZ dh vksj c<+ ldrh gSA ;g ekWMy] Hkkjrh; leqnz ds nf{k.kh Hkkxksa esa 8° & 10° m- ds chp 100 gS- ik- ¼Vh- bZ- ts- dksj dk Lrj½ ij fo’ks"kdj ekulwu ds iwokZ)Z ds nkSjku m".kdfVca/kh; iwokZfHkeq[kh tsV¼Vh- bZ- ts-½ dks izHkkfor djrk gSA The paper presents the results of simulation experiments aimed at predicting the characteristic features of Asian Summer Monsoon during the middle of the century (2041-60) resulting from global climate change. The model used is HadRM2 regional climate model of the Hadley Centre for Climate Prediction and Research, UK. Two simulation experiments of 20 years length have been performed for the Asian domain, namely, one with a fixed amount of greenhouse gas concentration corresponding to 1990 levels called the 'control' (CTL) experiment and the other with the annual compound increase of 1 % in the greenhouse gas concentration for 2041-60 from 1990 onwards called the 'greenhouse gas' (GHG) experiment. The annual compound increment of 1 %, in the greenhouse gas concentration has been adopted from the projection given by the Intergovernmental Panel for Climate Change (IPCC). The experiments have brought out some of the changes in the characteristic features of mid-century Asian summer monsoons that are expected to occur due to increased anthropogenic emissions. The most significant change seems to be a general northward shift of the monsoon trough (MT) in the lower troposphere (850 hPa) throughout the monsoon season over the Indian region. The simulation results have shown an increase of about 1-2 hPa in the sea level pressure (SLP) over the Arabian Sea during the monsoon resulting in an anomalous anticyclone over there in the lower troposphere. This would mean the weakening of Low Level Jet (LLJ) and the Arabian sea branch of the monsoon current. The model has simulated a decrease in the frequency of the monsoonal cyclonic disturbances over the north Indian Ocean under the warmer sea surface conditions which conforms to the observed decreasing trends in the frequency of monsoon depressions in recent decades. The experiments have shown that the Heat Low over Pakistan and adjoining northwest India, may intensify and shift slightly eastward during the monsoon. The model has simulated the strengthening of Tropical Easterly Jet (TEJ) at          100 hPa (the location of TEJ core ) over the southern parts of Indian sea between 8° - 10° N, especially during the first half of the monsoon season.


1989 ◽  
Vol 26 (2) ◽  
pp. 214-221 ◽  
Author(s):  
Subhash Sharma ◽  
Srinivas Durvasula ◽  
William R. Dillon

The authors report some results on the behavior of alternative covariance structure estimation procedures in the presence of non-normal data. They conducted Monté Carlo simulation experiments with a factorial design involving three levels of skewness, three level of kurtosis, and three different sample sizes. For normal data, among all the elliptical estimation techniques, elliptical reweighted least squares (ERLS) was equivalent in performance to ML. However, as expected, for non-normal data parameter estimates were unbiased for ML and the elliptical estimation techniques, whereas the bias in standard errors was substantial for GLS and ML. Among elliptical estimation techniques, ERLS was superior in performance. On the basis of the simulation results, the authors recommend that researchers use ERLS for both normal and non-normal data.


2014 ◽  
Vol 472 ◽  
pp. 574-578 ◽  
Author(s):  
Hai Tao Chen ◽  
Peng Yang ◽  
Run Cang Yu

In emergencies such as fire, pedestrian evacuation for bad visibility is significantly different to the evacuation for normal visibility. In the novel evacuation model, the strategies of pedestrian evacuation and the moving rules are proposed. Then the formulas of the evacuation time are achieved and the time ratio is 0.63. More, using the programming language, pedestrian evacuation is simulated and reproduced. The studies shows that the proposed evacuation model can well reflect the process of pedestrian evacuation; and the evacuation signs of reasonable design can significantly optimize the process. The calculation results also show that the ratio of evacuation time between considering evacuation signs and no evacuation signs is close to 0.63 that is the theoretical results.


2011 ◽  
Vol 12 (1) ◽  
pp. 28-47
Author(s):  
Enang Bassey Udah

The dynamic nexus between money supply, fiscal deficit, inflation, output and exchange rate management has recently generated much debate in economic literature in Nigeria. To contribute to this debate, this paper uses the co-integration and error correction framework of analysis and also conducts policy simulation experiments to investigate how monetary variables interact with aggregate supply, demand and prices in order to aid stabilization policies. The results show that monetary variables and government finance are linked through government’s net indebtedness to the banking system. The simulation results show that a 20 per cent monetary squeeze would reduce the inflation rate faster than if the reduction in money supply were 10 per cent. This reduction in money supply would also lead to a reduction in output, employment and government expenditure, which may hurt the domestic economy. The paper thus concludes that there is a trade-off between higher GDP growth and inflation in Nigeria.


2012 ◽  
Vol 614-615 ◽  
pp. 1841-1845
Author(s):  
Yong Wei Zheng ◽  
Min You Chen ◽  
Chuang Li ◽  
Rui Lin Xu ◽  
Xin Xu

A microgrid model with distributed generation including small hydropower source and wind generation source is presented in this paper. The corresponding control strategies for this microgrid are developed. Simulation experiments on island operation mode using Matlab/Simulink software program have been conducted. The simulation results show that the microgrid can operate stably and reliably for load power supply.


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