Pub Date : 2025-02-01DOI: 10.1016/j.physa.2024.130336
Tiankai Zhao , Hongyan Yuan , Xiongfei Zheng
Epithelial cells form cohesive colonies that interact with substrates by generating extracellular forces through focal adhesions. This study develops a thermodynamic model integrating monolayer elasticity and force-mediated focal adhesion formation to understand how epithelial-substrate-coupling strength affects traction forces, cellular displacements, and focal adhesion distributions in cohesive monolayers. We derive and solve the steady-state equations of the system both semi-analytically and numerically. Our findings show that epithelial-substrate-coupling strength significantly influences traction force landscapes and focal adhesion distributions. Strong coupling increases average traction force as colony size decreases, while weak coupling shows the opposite trend. This model reconciles previously observed differences in scaling laws relating average traction force to colony size.
{"title":"Thermodynamic model of epithelial-substrate coupling in monolayers: Effects on traction forces and colony size","authors":"Tiankai Zhao , Hongyan Yuan , Xiongfei Zheng","doi":"10.1016/j.physa.2024.130336","DOIUrl":"10.1016/j.physa.2024.130336","url":null,"abstract":"<div><div>Epithelial cells form cohesive colonies that interact with substrates by generating extracellular forces through focal adhesions. This study develops a thermodynamic model integrating monolayer elasticity and force-mediated focal adhesion formation to understand how epithelial-substrate-coupling strength affects traction forces, cellular displacements, and focal adhesion distributions in cohesive monolayers. We derive and solve the steady-state equations of the system both semi-analytically and numerically. Our findings show that epithelial-substrate-coupling strength significantly influences traction force landscapes and focal adhesion distributions. Strong coupling increases average traction force as colony size decreases, while weak coupling shows the opposite trend. This model reconciles previously observed differences in scaling laws relating average traction force to colony size.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130336"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160684","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130344
A. Escobar , R. Reyes-Aguilar , C.G. Vidales-Hernández , J.L. Carrillo-Estrada , F. Donado
We studied the transition from persistent to diffusive motion when varying particle concentrations in two different 2D active and macroscopic systems. The first one comprises magnetic spherical steel particles under an alternating magnetic field, which turns them into self-propelled stochastic particles. The second system is composed of a set of Hexbug-nano™ robots. Each of those tiny robots has an internal motor that, in combination with its elongated and inclined shape and the flexibility of its legs, provides it with persistent motion. We discovered that both systems similarly behave when varying the particle concentration and the available area for motion. Our results show that particle motions exhibit persistence when the concentration of active particles is low. As the particle concentration increases, until a threshold, the interactions between them grow in number, forcing them to change their direction more frequently and, turning diffusive their behaviour. New emergent phenomena are observed when a high particle concentration regime is explored. The formation of aggregates is observed, and the free particles consequently move in open spaces with less particle concentration recovering their persistent motion. The collective synchronization of particle motion is observed in a range of particle concentrations.
{"title":"Effect of particle concentration on the persistence of motion in active matter systems","authors":"A. Escobar , R. Reyes-Aguilar , C.G. Vidales-Hernández , J.L. Carrillo-Estrada , F. Donado","doi":"10.1016/j.physa.2024.130344","DOIUrl":"10.1016/j.physa.2024.130344","url":null,"abstract":"<div><div>We studied the transition from persistent to diffusive motion when varying particle concentrations in two different 2D active and macroscopic systems. The first one comprises magnetic spherical steel particles under an alternating magnetic field, which turns them into self-propelled stochastic particles. The second system is composed of a set of Hexbug-nano™ robots. Each of those tiny robots has an internal motor that, in combination with its elongated and inclined shape and the flexibility of its legs, provides it with persistent motion. We discovered that both systems similarly behave when varying the particle concentration and the available area for motion. Our results show that particle motions exhibit persistence when the concentration of active particles is low. As the particle concentration increases, until a threshold, the interactions between them grow in number, forcing them to change their direction more frequently and, turning diffusive their behaviour. New emergent phenomena are observed when a high particle concentration regime is explored. The formation of aggregates is observed, and the free particles consequently move in open spaces with less particle concentration recovering their persistent motion. The collective synchronization of particle motion is observed in a range of particle concentrations.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130344"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161213","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130311
Katja Biswas, Anil K. Katwal
We study the energy landscapes of three spin models, comprised of 36 spins, confined to a Snub Archimedean lattice of type (, 4,3,4). Our models differ in the possible range of spin–spin interaction, namely , , and . Characteristic of discrete interactions these spin systems can exhibit extended minimum energy structures which are categorized into four types, namely regular minima, type-1 dales, type-2 dales, and type-3 dales. The different types are distinguished in the disconnectivity graphs via colors and their sizes are indicated for the different energy levels via a bar chart. Each of the models shows distinct features in the structure of the energy landscapes. The model only exhibits regular minima, whereas all types are found in the and models. Their landscapes resemble a palm leaf structure with increasing occurrence of multiple funnels for increasing range of bonds. Further evaluation of these structures reveals that the majority of the minima occupy the medium energy range and that all the structures exhibit high barriers at low energies and low barriers at medium to high energies indicative that low energy traps are more difficult to escape than high energy traps. The length of the transition paths from the minima structures to the transition states allows an investigation into the applicability of Hammond’s postulate to spin systems. The results suggest that for the model statistically the configurations of the transition states are closer related to the minima that require less increase in energy than to the minima that require a larger increase in energy. However, due to the presence of flat energy structures, and a larger bond range in the and models this occurs only up to medium energies.
{"title":"Energy landscapes of spin models on the Snub Archimedean ( 32, 4, 3, 4) lattice","authors":"Katja Biswas, Anil K. Katwal","doi":"10.1016/j.physa.2024.130311","DOIUrl":"10.1016/j.physa.2024.130311","url":null,"abstract":"<div><div>We study the energy landscapes of three spin models, comprised of 36 spins, confined to a Snub Archimedean lattice of type (<span><math><msup><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></msup></math></span>, 4,3,4). Our models differ in the possible range of spin–spin interaction, namely <span><math><mrow><mo>{</mo><mo>±</mo><mn>1</mn><mo>}</mo></mrow></math></span>, <span><math><mrow><mo>{</mo><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn><mo>}</mo></mrow></math></span>, and <span><math><mrow><mo>{</mo><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn><mo>,</mo><mo>±</mo><mn>3</mn><mo>}</mo></mrow></math></span>. Characteristic of discrete interactions these spin systems can exhibit extended minimum energy structures which are categorized into four types, namely regular minima, type-1 dales, type-2 dales, and type-3 dales. The different types are distinguished in the disconnectivity graphs via colors and their sizes are indicated for the different energy levels via a bar chart. Each of the models shows distinct features in the structure of the energy landscapes. The <span><math><mrow><mo>±</mo><mn>1</mn></mrow></math></span> model only exhibits regular minima, whereas all types are found in the <span><math><mrow><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn></mrow></math></span> and <span><math><mrow><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn><mo>,</mo><mo>±</mo><mn>3</mn></mrow></math></span> models. Their landscapes resemble a palm leaf structure with increasing occurrence of multiple funnels for increasing range of bonds. Further evaluation of these structures reveals that the majority of the minima occupy the medium energy range and that all the structures exhibit high barriers at low energies and low barriers at medium to high energies indicative that low energy traps are more difficult to escape than high energy traps. The length of the transition paths from the minima structures to the transition states allows an investigation into the applicability of Hammond’s postulate to spin systems. The results suggest that for the <span><math><mrow><mo>±</mo><mn>1</mn></mrow></math></span> model statistically the configurations of the transition states are closer related to the minima that require less increase in energy than to the minima that require a larger increase in energy. However, due to the presence of flat energy structures, and a larger bond range in the <span><math><mrow><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn></mrow></math></span> and <span><math><mrow><mo>±</mo><mn>1</mn><mo>,</mo><mo>±</mo><mn>2</mn><mo>,</mo><mo>±</mo><mn>3</mn></mrow></math></span> models this occurs only up to medium energies.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130311"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161257","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130331
Xiaojian Hu , Fengkai Yu
Because of their substantial weight, trucks frequently brake to control their speed on long downhill sections, placing a significant load on the brakes. After traveling a certain distance, this leads to degradation of the brake performance and poses a considerable traffic safety hazard. This study analyzes the energy transformation of trucks on long downhill sections using the law of energy conservation, and derives the relationship between brake performance and travel distance. Within the framework of Kerner's three-phase traffic theory, the impact of brake performance degradation on traffic flow in long downhill sections was studied. This model is based on the well-known Kerner–Klenov–Schreckeneberg–Wolf (KKSW) cellular automaton (CA) model. By comparing the traffic flow under different traffic volume and truck percentage scenarios, it was found that the synchronized flow generated under certain traffic volume and truck proportion conditions has a particularly significant impact upstream. Based on the simulation results, a lane segregation strategy is proposed for certain traffic volumes and truck percentages.
{"title":"Objective description of heterogeneous traffic flow patterns of passenger cars and trucks on long downhill sections in Kerner's three-phase traffic theory framework","authors":"Xiaojian Hu , Fengkai Yu","doi":"10.1016/j.physa.2024.130331","DOIUrl":"10.1016/j.physa.2024.130331","url":null,"abstract":"<div><div>Because of their substantial weight, trucks frequently brake to control their speed on long downhill sections, placing a significant load on the brakes. After traveling a certain distance, this leads to degradation of the brake performance and poses a considerable traffic safety hazard. This study analyzes the energy transformation of trucks on long downhill sections using the law of energy conservation, and derives the relationship between brake performance and travel distance. Within the framework of Kerner's three-phase traffic theory, the impact of brake performance degradation on traffic flow in long downhill sections was studied. This model is based on the well-known Kerner–Klenov–Schreckeneberg–Wolf (KKSW) cellular automaton (CA) model. By comparing the traffic flow under different traffic volume and truck percentage scenarios, it was found that the synchronized flow generated under certain traffic volume and truck proportion conditions has a particularly significant impact upstream. Based on the simulation results, a lane segregation strategy is proposed for certain traffic volumes and truck percentages.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130331"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160750","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130329
Danni Wang , Nan Liu , Hongli Yang , Liangui Yang
A delayed gene regulatory network model is established to describe biological discrete-time systems. Using stability analysis, the influence of time delay on discrete systems is illustrated. The direction and stability of Neimark–Sacker bifurcation are explored by using the normal form method and central manifold theorem. The hybrid control scheme is proposed and the bifurcation properties of controlled system are exhibited. Theoretical analysis and numerical simulation demonstrate that time delay causes oscillations in the system within a certain range and reveal that different feedback intensities affect the amplitude and period of the system. These results enrich our understanding of the impact of the feedback coupled loops with time delays on discrete system dynamics.
{"title":"Bifurcation analysis and control on the delayed gene regulatory models","authors":"Danni Wang , Nan Liu , Hongli Yang , Liangui Yang","doi":"10.1016/j.physa.2024.130329","DOIUrl":"10.1016/j.physa.2024.130329","url":null,"abstract":"<div><div>A delayed gene regulatory network model is established to describe biological discrete-time systems. Using stability analysis, the influence of time delay on discrete systems is illustrated. The direction and stability of Neimark–Sacker bifurcation are explored by using the normal form method and central manifold theorem. The hybrid control scheme is proposed and the bifurcation properties of controlled system are exhibited. Theoretical analysis and numerical simulation demonstrate that time delay causes oscillations in the system within a certain range and reveal that different feedback intensities affect the amplitude and period of the system. These results enrich our understanding of the impact of the feedback coupled loops with time delays on discrete system dynamics.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130329"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160751","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130334
Xiaoxiao Huang, Gang Zhang, Jiaqi Xu
In this paper, we propose a method that combines Ensemble Empirical Mode Decomposition (EEMD) with a Multi-parameter Constrained Time-delay Feedback Tri-stable Stochastic Resonance (MCTFTSR) system. We discuss its performance for fault signal diagnosis characterized by non-stationarity, multi-components, and multi-interferences. Initially, we propose and study MCTFTSR system driven by Gaussian white noise and periodic signal. Following that, the equivalent potential function, steady-state probability density (SPD), mean first passage time (MFPT) and spectral amplification coefficient (SA) of MCTFTSR system are derived by using the small time-delay approximation. Next, we discuss the impact of parameters on MCTFTSR system from the perspectives of particle residence probability, transition and output characteristics. Subsequently, we employ numerical simulations to contrast the output performance of the MCTFTSR, MCTSR, and TFSTSR systems. The results indicate that, in comparison to the other two systems, MCTFTSR exhibits superior detection performance under various driving frequency signal, Gaussian noise and Levy noise. Additionally, we simulate faulty AM signal to assess the applicability and superior detection capabilities of the EEMD-MCTFTSR method. It is found that the method can enhance and extract the characteristics of AM signals, to identify faults effectively. Finally, the proposed method is applied to practical engineering and compared with the EEMD method, MCTFTSR method. Genetic algorithm (GA) is used to obtain the optimal parameter combination and ensure the most effective fault signal detection. In the inner ring fault diagnosis, the SNRI of the proposed method is 0.54 dB and 7.6 dB higher than that of EEMD and MCTFTSR, respectively, while in the outer ring fault diagnosis it is 3.02 dB and 8.05 dB higher. The results show that the EEMD-MCTFTSR method exhibits superior denoising and signal extraction capabilities compared to the other two methods, which further enhances the application of SR in bearing fault diagnosis.
{"title":"Adaptive multi-parameter constrained time-delay feedback tri-stable stochastic resonance combined with EEMD for rolling bearing fault diagnosis","authors":"Xiaoxiao Huang, Gang Zhang, Jiaqi Xu","doi":"10.1016/j.physa.2024.130334","DOIUrl":"10.1016/j.physa.2024.130334","url":null,"abstract":"<div><div>In this paper, we propose a method that combines Ensemble Empirical Mode Decomposition (EEMD) with a Multi-parameter Constrained Time-delay Feedback Tri-stable Stochastic Resonance (MCTFTSR) system. We discuss its performance for fault signal diagnosis characterized by non-stationarity, multi-components, and multi-interferences. Initially, we propose and study MCTFTSR system driven by Gaussian white noise and periodic signal. Following that, the equivalent potential function, steady-state probability density (SPD), mean first passage time (MFPT) and spectral amplification coefficient (SA) of MCTFTSR system are derived by using the small time-delay approximation. Next, we discuss the impact of parameters on MCTFTSR system from the perspectives of particle residence probability, transition and output characteristics. Subsequently, we employ numerical simulations to contrast the output performance of the MCTFTSR, MCTSR, and TFSTSR systems. The results indicate that, in comparison to the other two systems, MCTFTSR exhibits superior detection performance under various driving frequency signal, Gaussian noise and Levy noise. Additionally, we simulate faulty AM signal to assess the applicability and superior detection capabilities of the EEMD-MCTFTSR method. It is found that the method can enhance and extract the characteristics of AM signals, to identify faults effectively. Finally, the proposed method is applied to practical engineering and compared with the EEMD method, MCTFTSR method. Genetic algorithm (GA) is used to obtain the optimal parameter combination and ensure the most effective fault signal detection. In the inner ring fault diagnosis, the SNRI of the proposed method is 0.54 dB and 7.6 dB higher than that of EEMD and MCTFTSR, respectively, while in the outer ring fault diagnosis it is 3.02 dB and 8.05 dB higher. The results show that the EEMD-MCTFTSR method exhibits superior denoising and signal extraction capabilities compared to the other two methods, which further enhances the application of SR in bearing fault diagnosis.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130334"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160746","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 : 2025-02-01DOI: 10.1016/j.physa.2025.130349
Lucas R. Rodrigues , Tiago J. Oliveira , Jürgen F. Stilck
We study the thermodynamic behavior of hard rigid rods of size (i.e., -mers) on four- and six-coordinated Husimi lattices (HLs), respectively built with squares (square HL) and triangles (triangular HL). In both lattices, dimers () and trimers () only present a isotropic phase, whereas a isotropic-nematic transition is observed for . In the square HL, this transition is continuous and occurs at a critical monomer activity which displays a nonmonotonic variation with , while the critical rod activity and density are always decreasing functions of . The isotropic-nematic transition is discontinuous in the triangular HL, but the -dependence of the coexistence activities and density is analogous to that found for the square case. No transition from the nematic to a high-density disordered phase is found in these HLs. In general, this scenario is very similar to that already observed for rods on the Bethe lattice, though the critical parameters obtained her e are in most cases closer to those reported in the literature for the square and triangular lattices. The entropy per site of fully-packed rods is also investigated in detail in the triangular HL, where its value for dimers differs by only 0.7% from the exact result for the triangular lattice.
{"title":"Hard rigid rods on Husimi lattices","authors":"Lucas R. Rodrigues , Tiago J. Oliveira , Jürgen F. Stilck","doi":"10.1016/j.physa.2025.130349","DOIUrl":"10.1016/j.physa.2025.130349","url":null,"abstract":"<div><div>We study the thermodynamic behavior of hard rigid rods of size <span><math><mi>k</mi></math></span> (i.e., <span><math><mi>k</mi></math></span>-mers) on four- and six-coordinated Husimi lattices (HLs), respectively built with squares (square HL) and triangles (triangular HL). In both lattices, dimers (<span><math><mrow><mi>k</mi><mo>=</mo><mn>2</mn></mrow></math></span>) and trimers (<span><math><mrow><mi>k</mi><mo>=</mo><mn>3</mn></mrow></math></span>) only present a isotropic phase, whereas a isotropic-nematic transition is observed for <span><math><mrow><mi>k</mi><mo>≥</mo><mn>4</mn></mrow></math></span>. In the square HL, this transition is continuous and occurs at a critical <em>monomer</em> activity which displays a nonmonotonic variation with <span><math><mi>k</mi></math></span>, while the critical <em>rod</em> activity and density are always decreasing functions of <span><math><mi>k</mi></math></span>. The isotropic-nematic transition is discontinuous in the triangular HL, but the <span><math><mi>k</mi></math></span>-dependence of the coexistence activities and density is analogous to that found for the square case. No transition from the nematic to a high-density disordered phase is found in these HLs. In general, this scenario is very similar to that already observed for rods on the Bethe lattice, though the critical parameters obtained her e are in most cases closer to those reported in the literature for the square and triangular lattices. The entropy per site of fully-packed rods is also investigated in detail in the triangular HL, where its value for dimers differs by only 0.7% from the exact result for the triangular lattice.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130349"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161294","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}
This study examines the statistical properties of explosive eruptions at Japan’s Sakurajima volcano from 1955 to 2023. The investigation revealed that the distribution of eruption intervals conforms to a power-law distribution. Additionally, a Hurst exponent of approximately 0.81 was computed for the monthly average daily frequency of explosive eruptions. Based on these findings, it was determined that the occurrence of explosive eruptions of Sakurajima volcano over the period of study deviates from a Poisson process and exhibits characteristics of a non-stationary Poisson process influenced by prior explosive events. Subsequent modeling using the autoregressive integrated moving average (ARIMA) technique showed that the ARIMA(1,1,0) model provides an excellent fit to the observed data.
{"title":"Time series analysis and stochastic processes modeling using explosive eruption data from Japan’s Sakurajima volcano","authors":"Ryuji Ishizaki , Masayoshi Inoue , Kazuhiro Fukushima","doi":"10.1016/j.physa.2024.130313","DOIUrl":"10.1016/j.physa.2024.130313","url":null,"abstract":"<div><div>This study examines the statistical properties of explosive eruptions at Japan’s Sakurajima volcano from 1955 to 2023. The investigation revealed that the distribution of eruption intervals conforms to a power-law distribution. Additionally, a Hurst exponent of approximately 0.81 was computed for the monthly average daily frequency of explosive eruptions. Based on these findings, it was determined that the occurrence of explosive eruptions of Sakurajima volcano over the period of study deviates from a Poisson process and exhibits characteristics of a non-stationary Poisson process influenced by prior explosive events. Subsequent modeling using the autoregressive integrated moving average (ARIMA) technique showed that the ARIMA(1,1,0) model provides an excellent fit to the observed data.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130313"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160685","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 : 2025-02-01DOI: 10.1016/j.physa.2024.130345
Zhijian Fu , Shengxian Yang , Lin Luo , Jian Li , Xiaobo Liu
This study investigates pedestrian dynamics and crowd risk on ramps, a topic not fully explored in previous research. Our experimental setup covers a boarder range of densities for both walking and running scenarios. Our main findings include: (1) Once pedestrian density exceeds 1.70ped/m2, flow rates continue to increase and remain consistently higher during ascending the ramp compared to descending, a trend not observed on level ground. This phenomenon can be explained by step behavior mechanisms, driven by the transition from two to three lanes, which help maintain consistent headway and step lengths. (2) The addition of walking lanes increases velocity curl (i.e., local spinning motion) on the ascending segment, especially in running scenarios. When combined with the high-density levels typically seen in ascending movement, these effects amplify crowd danger. Statistical analyses confirm crowd risks are more strongly correlate with movement directions (descending vs. ascending) than with movement speeds (walking vs. running).
{"title":"Experimental study of pedestrian dynamics and crowd risk on ramps","authors":"Zhijian Fu , Shengxian Yang , Lin Luo , Jian Li , Xiaobo Liu","doi":"10.1016/j.physa.2024.130345","DOIUrl":"10.1016/j.physa.2024.130345","url":null,"abstract":"<div><div>This study investigates pedestrian dynamics and crowd risk on ramps, a topic not fully explored in previous research. Our experimental setup covers a boarder range of densities for both walking and running scenarios. Our main findings include: (1) Once pedestrian density exceeds 1.70ped/m<sup>2</sup>, flow rates continue to increase and remain consistently higher during ascending the ramp compared to descending, a trend not observed on level ground. This phenomenon can be explained by step behavior mechanisms, driven by the transition from two to three lanes, which help maintain consistent headway and step lengths. (2) The addition of walking lanes increases velocity curl (i.e., local spinning motion) on the ascending segment, especially in running scenarios. When combined with the high-density levels typically seen in ascending movement, these effects amplify crowd danger. Statistical analyses confirm crowd risks are more strongly correlate with movement directions (descending vs. ascending) than with movement speeds (walking vs. running).</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130345"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160747","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 : 2025-02-01DOI: 10.1016/j.physa.2025.130366
Zelin Nie , Yuxin Guan , Wei Cheng , Lingxiu Chen , Ji Xing , Xuefeng Chen , Na Xue , Jin Yan , Wei Deng , Qun Cao
At present, the measures for on-site emergency in nuclear power plants are not universal and flexible, and are not applicable to all accident scenarios. To address the problem, this paper proposes a Macro guidance-Micro avoidance model combined improved Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Cellular Automata (CA) model for on-site emergency. To overcome the issue of “repeated turnback” in CA micro-simulation, the improved NSGA-II algorithm is introduced to guide macro evacuation directions. For addressing uncertainty in the effects of radiation field, psychological factors, and evacuation behavior on evacuation efficiency in nuclear emergency scenarios, CA is used to simulate and analyze the influence rule of radiation field, herd behavior, information transmission, and physical differences on evacuation time. Finally, by selecting appropriate exit inside nuclear power plant, this model reasonably estimates evacuation time, and ensures timely response of off-site emergency vehicles during the nuclear emergency process. Through the simulation analysis of evacuation process of on-site personnel based on radionuclide diffusion, radiation hazards, crowd characteristics, and psychological changes can be considered, this approach facilitates the planning of safe evacuation exits and allows for more accurate evacuation time estimation, supporting subsequent off-site evacuation efforts.
{"title":"Macro guidance-Micro avoidance model for on-site personnel emergency evacuation strategy in nuclear power plants under fear psychology","authors":"Zelin Nie , Yuxin Guan , Wei Cheng , Lingxiu Chen , Ji Xing , Xuefeng Chen , Na Xue , Jin Yan , Wei Deng , Qun Cao","doi":"10.1016/j.physa.2025.130366","DOIUrl":"10.1016/j.physa.2025.130366","url":null,"abstract":"<div><div>At present, the measures for on-site emergency in nuclear power plants are not universal and flexible, and are not applicable to all accident scenarios. To address the problem, this paper proposes a Macro guidance-Micro avoidance model combined improved Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Cellular Automata (CA) model for on-site emergency. To overcome the issue of “repeated turnback” in CA micro-simulation, the improved NSGA-II algorithm is introduced to guide macro evacuation directions. For addressing uncertainty in the effects of radiation field, psychological factors, and evacuation behavior on evacuation efficiency in nuclear emergency scenarios, CA is used to simulate and analyze the influence rule of radiation field, herd behavior, information transmission, and physical differences on evacuation time. Finally, by selecting appropriate exit inside nuclear power plant, this model reasonably estimates evacuation time, and ensures timely response of off-site emergency vehicles during the nuclear emergency process. Through the simulation analysis of evacuation process of on-site personnel based on radionuclide diffusion, radiation hazards, crowd characteristics, and psychological changes can be considered, this approach facilitates the planning of safe evacuation exits and allows for more accurate evacuation time estimation, supporting subsequent off-site evacuation efforts.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"659 ","pages":"Article 130366"},"PeriodicalIF":2.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160639","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号