Pub Date : 2024-11-13DOI: 10.1016/j.physa.2024.130222
Huan Jin , Wenxun Sun , Xianan Qin
In a previous study [Physica A, 625 (2023), 129026], a relationship between the filler size distribution and the filler geometry of SiO2 particle reinforced polymer composites has been reported. It has been experimentally demonstrated that the size of hollow and solid SiO2 particles disperse in polymer matrix follows Weibull statistics with shape parameter at 2 and 3, respectively. This mechanism has not yet been verified in the one-dimensional (1D) case. In this paper, we study the length distribution of glass fibers in polymer composites. Our results show that the previous theory still holds for the 1D case. Thus, shape parameter of Weibull size statistics could be a potential indicator of filler geometry in SiO2 reinforced polymer composites. This interesting mechanism can be explained by the scaling nature behind the Weibull statistics. Our study has thus shed new light on the evolution of filler geometry during the fabrication process of polymer composites, and should be useful for the related fields.
{"title":"Shape parameter of Weibull size statistics is a potential indicator of filler geometry in SiO2 reinforced polymer composites","authors":"Huan Jin , Wenxun Sun , Xianan Qin","doi":"10.1016/j.physa.2024.130222","DOIUrl":"10.1016/j.physa.2024.130222","url":null,"abstract":"<div><div>In a previous study [Physica A, 625 (2023), 129026], a relationship between the filler size distribution and the filler geometry of SiO<sub>2</sub> particle reinforced polymer composites has been reported. It has been experimentally demonstrated that the size of hollow and solid SiO<sub>2</sub> particles disperse in polymer matrix follows Weibull statistics with shape parameter at 2 and 3, respectively. This mechanism has not yet been verified in the one-dimensional (1D) case. In this paper, we study the length distribution of glass fibers in polymer composites. Our results show that the previous theory still holds for the 1D case. Thus, shape parameter of Weibull size statistics could be a potential indicator of filler geometry in SiO<sub>2</sub> reinforced polymer composites. This interesting mechanism can be explained by the scaling nature behind the Weibull statistics. Our study has thus shed new light on the evolution of filler geometry during the fabrication process of polymer composites, and should be useful for the related fields.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130222"},"PeriodicalIF":2.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.physa.2024.130232
Wenke Zhang , Zhichao Zhang , Tao Wang , Tingting Nong , Yueyao Ma , Eric Wai Ming Lee , Meng Shi
In fire emergencies, pedestrians often face uncertainty about the safety of evacuation routes due to a lack of risk information, which makes the emergency evacuation highly challenging. Although risk information is crucial for effective evacuation, the effect of varying levels of risk information on fire evacuation remains insufficiently explored. This study aims to address this gap by investigating the influence of different levels of risk information on pedestrian evacuation through virtual experiments and survey. We conducted a series of multiplayer fire evacuation experiments in Minecraft. The risk information provided to pedestrians before evacuation was controlled at three levels: no risk information, partial risk information, and complete risk information, by giving different risk information cues. The results of experiments indicated that risk information can improve pedestrian evacuation efficiency during fire emergencies, while more complete risk information can further improve pedestrian evacuation efficiency. Additionally, an information transfer phenomenon was observed during fire evacuations, in which pedestrians adjusted their behaviour based on perceived fire, leading others to avoid the fire in advance. The analysis of pedestrian behaviour revealed that pedestrians did not exhibit imitative behaviour in evacuation direction choices during fire emergencies. Pedestrian route choices were significantly influenced by the initial distance of pedestrians relative to the exits. Moreover, complete risk information cues did not significantly influence pedestrians’ route choices compared with partial risk information cues. A post-experimental survey was conducted to assess pedestrians’ route choice preferences under different risk information cue scenarios. The results showed that pedestrians preferred the nearest route.
{"title":"Effects of risk information on pedestrian evacuation during fire emergencies: Virtual experiments and survey","authors":"Wenke Zhang , Zhichao Zhang , Tao Wang , Tingting Nong , Yueyao Ma , Eric Wai Ming Lee , Meng Shi","doi":"10.1016/j.physa.2024.130232","DOIUrl":"10.1016/j.physa.2024.130232","url":null,"abstract":"<div><div>In fire emergencies, pedestrians often face uncertainty about the safety of evacuation routes due to a lack of risk information, which makes the emergency evacuation highly challenging. Although risk information is crucial for effective evacuation, the effect of varying levels of risk information on fire evacuation remains insufficiently explored. This study aims to address this gap by investigating the influence of different levels of risk information on pedestrian evacuation through virtual experiments and survey. We conducted a series of multiplayer fire evacuation experiments in Minecraft. The risk information provided to pedestrians before evacuation was controlled at three levels: no risk information, partial risk information, and complete risk information, by giving different risk information cues. The results of experiments indicated that risk information can improve pedestrian evacuation efficiency during fire emergencies, while more complete risk information can further improve pedestrian evacuation efficiency. Additionally, an information transfer phenomenon was observed during fire evacuations, in which pedestrians adjusted their behaviour based on perceived fire, leading others to avoid the fire in advance. The analysis of pedestrian behaviour revealed that pedestrians did not exhibit imitative behaviour in evacuation direction choices during fire emergencies. Pedestrian route choices were significantly influenced by the initial distance of pedestrians relative to the exits. Moreover, complete risk information cues did not significantly influence pedestrians’ route choices compared with partial risk information cues. A post-experimental survey was conducted to assess pedestrians’ route choice preferences under different risk information cue scenarios. The results showed that pedestrians preferred the nearest route.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130232"},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It was recently shown that wet active matter can form synchronized rotating vortices in a square lattice, similar to an antiferromagnetic Ising model (by considering rotation direction as spin projection). In this study, we investigate whether such a correlated state occurs for a model of dry active matter. We achieve that by numerically simulating the dynamics of a system of active particles in the presence of two identical circular obstacles. Then, we measure the angular velocity correlation function of both vortices as a function of the obstacle diameter, their shortest separation (gap), and the particle density. When the correlation function is negative, both vortices rotate in contrary directions. They maintain this state by exchanging particles through the region between them, analogously to synchronized cogs. On the other hand, with a positive correlation function, a single rotating cluster emerges, and the particles move around the whole structure, similar to a belt strapped around the obstacles. Additionally, we observe the emergence of uncorrelated states at the transition between correlated states, in which only a single vortex is present, or in the large gap regime, in which the vortices are nearly independent on each other.
{"title":"Correlations between two vortices in dry active matter","authors":"Felipe P.S. Júnior , Jorge L.C. Domingos , F.Q. Potiguar , W.P. Ferreira","doi":"10.1016/j.physa.2024.130181","DOIUrl":"10.1016/j.physa.2024.130181","url":null,"abstract":"<div><div>It was recently shown that wet active matter can form synchronized rotating vortices in a square lattice, similar to an antiferromagnetic Ising model (by considering rotation direction as spin projection). In this study, we investigate whether such a correlated state occurs for a model of dry active matter. We achieve that by numerically simulating the dynamics of a system of active particles in the presence of two identical circular obstacles. Then, we measure the angular velocity correlation function of both vortices as a function of the obstacle diameter, their shortest separation (gap), and the particle density. When the correlation function is negative, both vortices rotate in contrary directions. They maintain this state by exchanging particles through the region between them, analogously to synchronized cogs. On the other hand, with a positive correlation function, a single rotating cluster emerges, and the particles move around the whole structure, similar to a belt strapped around the obstacles. Additionally, we observe the emergence of uncorrelated states at the transition between correlated states, in which only a single vortex is present, or in the large gap regime, in which the vortices are nearly independent on each other.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130181"},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.physa.2024.130213
Xia Zhou , Chong Lai , Kexin Luo
Following the ideas of prospect theory, a class of growth functions is used to characterize deterministic variations of firm size, which portrays the asymmetric efforts of the firm to achieve the desired size. Considering the differences in the ability of different firm size to cope with uncertainties, the Boltzmann equation for the evolution of firm size is constructed. Utilizing a suitable scaling limit, the Fokker–Planck equation is acquired and its explicit steady-state solution is derived. Our results illustrate that different choices of parameters in the growth function lead to various statistical laws for firm size, such as the Amoroso distribution, the lognormal distribution and Zipf’s law. Under certain conditions, inequality for the distribution of firm size decreases as firm size increases. The numerical analyses are presented to illustrate our results.
{"title":"An investigation of firm size distributions involving the growth functions","authors":"Xia Zhou , Chong Lai , Kexin Luo","doi":"10.1016/j.physa.2024.130213","DOIUrl":"10.1016/j.physa.2024.130213","url":null,"abstract":"<div><div>Following the ideas of prospect theory, a class of growth functions is used to characterize deterministic variations of firm size, which portrays the asymmetric efforts of the firm to achieve the desired size. Considering the differences in the ability of different firm size to cope with uncertainties, the Boltzmann equation for the evolution of firm size is constructed. Utilizing a suitable scaling limit, the Fokker–Planck equation is acquired and its explicit steady-state solution is derived. Our results illustrate that different choices of parameters in the growth function lead to various statistical laws for firm size, such as the Amoroso distribution, the lognormal distribution and Zipf’s law. Under certain conditions, inequality for the distribution of firm size decreases as firm size increases. The numerical analyses are presented to illustrate our results.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130213"},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.physa.2024.130229
Chenglin Guo , Feizhou Huo , Shihan Deng , Jianan Huang , Wei Zhang
In recent years, violent attacks have garnered significant attention from the international community and gradually evolved into a global issue. In responding to such emergencies, effective emergency evacuation is an essential means to ensure public safety. In order to explore the pedestrian evacuation dynamics in violent attacks and understand the behavioral characteristics of individuals and the dynamic interactions of groups during the evacuation process, this paper proposes an agent-based cellular automata evacuation model. First, each agent is assigned several internal attributes such as life value, panic value, and movement speed, and the assignments fully take into account the heterogeneity of individuals. Next, by setting the attack strategy of attackers and the evacuation mechanism of pedestrians, the complex system is modeled from a microscopic perspective. Finally, the effects of critical factors on the pedestrian evacuation process, such as panic coefficient, crowd structure, group ratio, attack distance and intensity, attacker location and number, and counterattack probability, are discussed through simulation. The results show that the tension caused by moderate panic is beneficial, but excessive panic will lead to increased evacuation time and fatalities. Meanwhile, the group behavior among pedestrians causes them to move relatively lagging, and the evacuation efficiency decreases as the group scale increases. Additionally, increases in attack intensity, attack distance, and attacker number all result in more casualties, and the consequences are most severe when multiple attackers operate separately, but counterattacks by pedestrians can significantly improve the overall safety of evacuation. Our study can provide some reference and basis for emergency management under violent attacks.
{"title":"An evacuation model considering pedestrian group behavior under violent attacks","authors":"Chenglin Guo , Feizhou Huo , Shihan Deng , Jianan Huang , Wei Zhang","doi":"10.1016/j.physa.2024.130229","DOIUrl":"10.1016/j.physa.2024.130229","url":null,"abstract":"<div><div>In recent years, violent attacks have garnered significant attention from the international community and gradually evolved into a global issue. In responding to such emergencies, effective emergency evacuation is an essential means to ensure public safety. In order to explore the pedestrian evacuation dynamics in violent attacks and understand the behavioral characteristics of individuals and the dynamic interactions of groups during the evacuation process, this paper proposes an agent-based cellular automata evacuation model. First, each agent is assigned several internal attributes such as life value, panic value, and movement speed, and the assignments fully take into account the heterogeneity of individuals. Next, by setting the attack strategy of attackers and the evacuation mechanism of pedestrians, the complex system is modeled from a microscopic perspective. Finally, the effects of critical factors on the pedestrian evacuation process, such as panic coefficient, crowd structure, group ratio, attack distance and intensity, attacker location and number, and counterattack probability, are discussed through simulation. The results show that the tension caused by moderate panic is beneficial, but excessive panic will lead to increased evacuation time and fatalities. Meanwhile, the group behavior among pedestrians causes them to move relatively lagging, and the evacuation efficiency decreases as the group scale increases. Additionally, increases in attack intensity, attack distance, and attacker number all result in more casualties, and the consequences are most severe when multiple attackers operate separately, but counterattacks by pedestrians can significantly improve the overall safety of evacuation. Our study can provide some reference and basis for emergency management under violent attacks.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130229"},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.physa.2024.130218
Hanchen Yu , Nan Jiang , Hongyun Yang , Jixin Shi , Zhenyu Han , Eric Wai Ming Lee , Lizhong Yang
Crowd gathering in public infrastructures increases the challenges to safety management. To control the risk of crowd accidents, it is crucial to investigate the specific pedestrian movement characteristics within typical facilities to ensure efficient and safe walking operations. Merging scenarios involve complex multi-directional movements and always be considered dangerous bottlenecks to trigger serious crowd accidents. It demonstrated that the merging angle and layout significantly affect the performance of merging structures. However, most studies treat those properties independently without systematically exploring their combined effects to reflect a more diverse and complex flow status in real situations. In this study, we conduct controlled experiments to investigate the pedestrian merging process with five different merging angles and three different merging layouts. By analyzing the movement status, congestion, and degree of order, the efficiency and risk of different merging scenarios are compared. The lower upstream velocity and faster clogging propagation can be observed as the merging angle increases. While in scenarios with a small merging angle under certain layouts, limited outflows and longer time intervals occur and the stagnation is more frequent. The walking space of pedestrians near the inner side is severely compressed, resulting in higher local density around the corner and exacerbating the clogging nearby. Furthermore, a new indicator named Harmony Index is proposed to describe the adaptability of crowds to different merging setups. These findings are beneficial for optimizing the safe design and crowd management strategies of public infrastructures, as well as the crowd movement setup in relevant modeling works.
{"title":"Empirical analysis of pedestrian merging process with different merging angles and merging layouts","authors":"Hanchen Yu , Nan Jiang , Hongyun Yang , Jixin Shi , Zhenyu Han , Eric Wai Ming Lee , Lizhong Yang","doi":"10.1016/j.physa.2024.130218","DOIUrl":"10.1016/j.physa.2024.130218","url":null,"abstract":"<div><div>Crowd gathering in public infrastructures increases the challenges to safety management. To control the risk of crowd accidents, it is crucial to investigate the specific pedestrian movement characteristics within typical facilities to ensure efficient and safe walking operations. Merging scenarios involve complex multi-directional movements and always be considered dangerous bottlenecks to trigger serious crowd accidents. It demonstrated that the merging angle and layout significantly affect the performance of merging structures. However, most studies treat those properties independently without systematically exploring their combined effects to reflect a more diverse and complex flow status in real situations. In this study, we conduct controlled experiments to investigate the pedestrian merging process with five different merging angles and three different merging layouts. By analyzing the movement status, congestion, and degree of order, the efficiency and risk of different merging scenarios are compared. The lower upstream velocity and faster clogging propagation can be observed as the merging angle increases. While in scenarios with a small merging angle under certain layouts, limited outflows and longer time intervals occur and the stagnation is more frequent. The walking space of pedestrians near the inner side is severely compressed, resulting in higher local density around the corner and exacerbating the clogging nearby. Furthermore, a new indicator named Harmony Index is proposed to describe the adaptability of crowds to different merging setups. These findings are beneficial for optimizing the safe design and crowd management strategies of public infrastructures, as well as the crowd movement setup in relevant modeling works.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130218"},"PeriodicalIF":2.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.physa.2024.130220
Shuchao Cao , Ying Zhou , Weihao Ma , Xiaolian Li , Ming Yao
Passenger evacuation in high-speed train carriages is a critical issue that has not been fully explored and understood in previous research. To investigate the evacuation process of passengers from the confined carriage, a fine-grid cellular automaton model considering passenger heterogeneity is proposed in this paper. The influences of passenger attributes, luggage-carrying behavior, exit width and window evacuation mode on evacuation dynamics are analyzed under various scenarios. The simulation results reveal that the evacuation efficiency decreases with the increase of the proportion of elderly passengers in the carriage. The evacuation time increases with the increment of luggage-carrying proportion and duration time of luggage collection. Passengers carrying luggage near the inner door can easily block the aisle. Therefore, appropriately increasing the width of the inner door can reduce exit congestion and facilitate the evacuation process. Furthermore, the evacuation efficiency is the highest when the escape window is located in the middle of carriage for only one window exit. For the two window exits conditions, the escape windows are uniformly distributed in the middle of carriage is more favorable for evacuation. The study is useful to design evacuation plans for passenger flow and improve the emergency management level of high-speed railway stations.
{"title":"Evacuation simulation of heterogeneous passengers in the confined carriage of high-speed train","authors":"Shuchao Cao , Ying Zhou , Weihao Ma , Xiaolian Li , Ming Yao","doi":"10.1016/j.physa.2024.130220","DOIUrl":"10.1016/j.physa.2024.130220","url":null,"abstract":"<div><div>Passenger evacuation in high-speed train carriages is a critical issue that has not been fully explored and understood in previous research. To investigate the evacuation process of passengers from the confined carriage, a fine-grid cellular automaton model considering passenger heterogeneity is proposed in this paper. The influences of passenger attributes, luggage-carrying behavior, exit width and window evacuation mode on evacuation dynamics are analyzed under various scenarios. The simulation results reveal that the evacuation efficiency decreases with the increase of the proportion of elderly passengers in the carriage. The evacuation time increases with the increment of luggage-carrying proportion and duration time of luggage collection. Passengers carrying luggage near the inner door can easily block the aisle. Therefore, appropriately increasing the width of the inner door can reduce exit congestion and facilitate the evacuation process. Furthermore, the evacuation efficiency is the highest when the escape window is located in the middle of carriage for only one window exit. For the two window exits conditions, the escape windows are uniformly distributed in the middle of carriage is more favorable for evacuation. The study is useful to design evacuation plans for passenger flow and improve the emergency management level of high-speed railway stations.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130220"},"PeriodicalIF":2.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.physa.2024.130224
D.G. Xenikos , V. Constantoudis
This work explores the sub-exponential power-law growth that is observed in human and animal epidemics, using percolation analysis. Through numerical simulations, it identifies a large class of diffusion cases on networks that can be classified under an extended version of the discrete Bass model, with solutions that i) follow the Weibull probability distribution, ii) are consistent with the large power-law growth exponents reported for epidemics such as covid-19, and iii) have a clear physical meaning in agent-based models with specific behavioral dynamics. In particular, the Weibull power exponent is related to the restricted mobility of agents regarding social confinement. The mathematical formalism then depicts the time dependent diffusion in human (covid-19) and animal (foot-and-mouth) epidemics. In addition, it is used to describe the spatiotemporal heterogeneous diffusion over modular networks that model interconnected geographical regions and is applied in the case of covid-19 diffusion across USA Counties.
{"title":"Extended Bass model on the power-law epidemics growth and its implications on spatially heterogeneous systems","authors":"D.G. Xenikos , V. Constantoudis","doi":"10.1016/j.physa.2024.130224","DOIUrl":"10.1016/j.physa.2024.130224","url":null,"abstract":"<div><div>This work explores the sub-exponential power-law growth that is observed in human and animal epidemics, using percolation analysis. Through numerical simulations, it identifies a large class of diffusion cases on networks that can be classified under an extended version of the discrete Bass model, with solutions that <em>i)</em> follow the Weibull probability distribution, <em>ii)</em> are consistent with the large power-law growth exponents <span><math><mrow><mi>β</mi><mo>></mo><mn>2</mn></mrow></math></span> reported for epidemics such as covid-19, and <em>iii)</em> have a clear physical meaning in agent-based models with specific behavioral dynamics. In particular, the Weibull power exponent is related to the restricted mobility of agents regarding social confinement. The mathematical formalism then depicts the time dependent diffusion in human (covid-19) and animal (foot-and-mouth) epidemics. In addition, it is used to describe the spatiotemporal heterogeneous diffusion over modular networks that model interconnected geographical regions and is applied in the case of covid-19 diffusion across USA Counties.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130224"},"PeriodicalIF":2.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With urban and public transportation development, the urban rail transit networks (URTN) become increasingly complex, evolving into multi-layer and intricate systems. The operating environment is complex, and the rising frequency of emergencies significantly impacts the entire network. Consequently, the resilient ability of URTN to deal with risk attacks has become an important research field. In this paper, a bilayer URTN model is constructed, encompassing urban and suburban rail transit, proposing the adjacency matrix and the coupling mechanism of subnetworks. Then, the performance of a URTN jointly considering network efficiency, network structure entropy, and the number of trips per unit time is addressed. By considering passenger travel alternatives under disruptions, we develop an improved Logit stochastic user equilibrium (SUE) passenger assignment model based on generalized travel time costs, introducing the failure degree of the stations, to predict passenger flow paths. A multi-dimensional resilience assessment model is proposed using the resilience change curve for attack scenarios and recovery strategies, and a comprehensive network performance system through the AHP method to determine the weight coefficients of indicators. Finally, we present a case study based on the Shanghai URT network to explore the resilience of URTN in the morning peak and simulate the network resilience under different failure scenarios. The results indicate that the proposed model can assess the resilience of the Shanghai MRTN under random and malicious failure, and the former has less comprehensive performance losses and greater resilience. Additionally, the sensitivity analysis is conducted to explore the impact of the number of failed stations, the failure degree of stations, and recovery ability on network resilience. This study provides theoretical support for urban managers and builders regarding network structure and emergency management, and offers relevant suggestions.
{"title":"Network-based resilience assessment of an urban rail transit infrastructure with a multi-dimensional performance metric","authors":"Mingchang Zhu , Xiaoqing Zeng , Peiran Ying , Lixia Bao","doi":"10.1016/j.physa.2024.130211","DOIUrl":"10.1016/j.physa.2024.130211","url":null,"abstract":"<div><div>With urban and public transportation development, the urban rail transit networks (URTN) become increasingly complex, evolving into multi-layer and intricate systems. The operating environment is complex, and the rising frequency of emergencies significantly impacts the entire network. Consequently, the resilient ability of URTN to deal with risk attacks has become an important research field. In this paper, a bilayer URTN model is constructed, encompassing urban and suburban rail transit, proposing the adjacency matrix and the coupling mechanism of subnetworks. Then, the performance of a URTN jointly considering network efficiency, network structure entropy, and the number of trips per unit time is addressed. By considering passenger travel alternatives under disruptions, we develop an improved Logit stochastic user equilibrium (SUE) passenger assignment model based on generalized travel time costs, introducing the failure degree of the stations, to predict passenger flow paths. A multi-dimensional resilience assessment model is proposed using the resilience change curve for attack scenarios and recovery strategies, and a comprehensive network performance system through the AHP method to determine the weight coefficients of indicators. Finally, we present a case study based on the Shanghai URT network to explore the resilience of URTN in the morning peak and simulate the network resilience under different failure scenarios. The results indicate that the proposed model can assess the resilience of the Shanghai MRTN under random and malicious failure, and the former has less comprehensive performance losses and greater resilience. Additionally, the sensitivity analysis is conducted to explore the impact of the number of failed stations, the failure degree of stations, and recovery ability on network resilience. This study provides theoretical support for urban managers and builders regarding network structure and emergency management, and offers relevant suggestions.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130211"},"PeriodicalIF":2.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1016/j.physa.2024.130216
Lang Zhang, Heng Ding, Zhen Feng, Liangwen Wang, Yunran Di, Xiaoyan Zheng, Shiguang Wang
To accurately predict traffic flow and optimize the operations of freeway bottleneck areas in a mixed-vehicle driving environment, this paper proposes a traffic prediction model and a variable speed limit (VSL) cooperative control strategy. Firstly, a lane-level short-term traffic prediction model, physics informed Transformer and cell transmission model (PIT-CTM), is constructed by combining the Transformer neural network and lane-level cell transmission model (CTM) based on the physics-informed deep learning framework. On this basis, the accuracy and transferability of PIT-CTM are analysed. Secondly, a lane assignment decision model is presented, which enables the dynamic planning of the optimal traffic distribution across lanes. Furthermore, a lane-level VSL control model is constructed based on the model predictive control (MPC) framework. The model induces vehicles to change lanes earlier by setting the speed limit difference between lanes. By regulating the input flow in the bottleneck area of the freeway, it reduces conflicts between mainline vehicles and ramp vehicles. Finally, the feedback regulation between the lane assignment decision model and the lane-level VSL control model promotes the cooperative optimisation of the lateral and longitudinal flows and adapts the control strategy to the dynamic traffic characteristics. A three-lane freeway merging zone is selected, the numerical experiment is conducted and compared with differential lane-level VSL. The results show that the strategy can effectively optimise the mixed-vehicle traffic state and maintain better control performance under any connected and autonomous vehicle (CAV) penetration rates.
{"title":"Variable speed limit control strategy considering traffic flow lane assignment in mixed-vehicle driving environment","authors":"Lang Zhang, Heng Ding, Zhen Feng, Liangwen Wang, Yunran Di, Xiaoyan Zheng, Shiguang Wang","doi":"10.1016/j.physa.2024.130216","DOIUrl":"10.1016/j.physa.2024.130216","url":null,"abstract":"<div><div>To accurately predict traffic flow and optimize the operations of freeway bottleneck areas in a mixed-vehicle driving environment, this paper proposes a traffic prediction model and a variable speed limit (VSL) cooperative control strategy. Firstly, a lane-level short-term traffic prediction model, physics informed Transformer and cell transmission model (PIT-CTM), is constructed by combining the Transformer neural network and lane-level cell transmission model (CTM) based on the physics-informed deep learning framework. On this basis, the accuracy and transferability of PIT-CTM are analysed. Secondly, a lane assignment decision model is presented, which enables the dynamic planning of the optimal traffic distribution across lanes. Furthermore, a lane-level VSL control model is constructed based on the model predictive control (MPC) framework. The model induces vehicles to change lanes earlier by setting the speed limit difference between lanes. By regulating the input flow in the bottleneck area of the freeway, it reduces conflicts between mainline vehicles and ramp vehicles. Finally, the feedback regulation between the lane assignment decision model and the lane-level VSL control model promotes the cooperative optimisation of the lateral and longitudinal flows and adapts the control strategy to the dynamic traffic characteristics. A three-lane freeway merging zone is selected, the numerical experiment is conducted and compared with differential lane-level VSL. The results show that the strategy can effectively optimise the mixed-vehicle traffic state and maintain better control performance under any connected and autonomous vehicle (CAV) penetration rates.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"656 ","pages":"Article 130216"},"PeriodicalIF":2.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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