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Abstract Most of previous research on complex networks always concentrates on topology, ignoring the coordinates of components. However, the spatial information of components may be a key factor influencing the invulnerability of actual networks. For interdependent infrastructures, considering space constraints, dependency links may be established locally, where only nodes within certain connection radius r c o n n e c t can be connected as dependent node pairs. Therefore, based on the topology-based cascading failure model, the invulnerability of interdependent scale-free networks is studied by introducing five coupling patterns in this paper, including global and local random couplings GR and LR , global and local degree–degree inter-similarity couplings GD and LD and nearest neighbor coupling NN. Under topological attacks, the inter-similarity couplings GD and LD have better performance, and as r c o n n e c t increases, the effect of LD will gradually approach to GD. In order to ensure a good invulnerability and low construction cost, a novel hybrid coupling pattern of NN and LD is proposed. With numerical simulations, we find that selecting nodes with large degree to establish LD coupling has significant effect, and there is an optimal selection fraction. Under localized attacks, the local couplings perform better, and LD is better for small r c o n n e c t while NN is better for large r c o n n e c t. In addition, we also study a simplified localized attacking strategy analytically based on percolation theory, which is proved to be consistent with the numerical results. For LD coupling, the effect will be influenced by r c o n n e c t , and there are minimum and maximum invulnerability values for topological and localized attacks, respectively. These findings can help to understand the characteristics of spatially embedded interdependent infrastructures. Highlights • The connection radius of dependency links is studied based on network connectivity. • A hybrid coupling is proposed to ensure invulnerability and short dependency links. • A simplified localized attacking strategy is studied based on percolation theory. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the finite-time event-triggered synchronization problem of the reaction–diffusion complex networks (RDCNs) with Dirichlet boundary conditions. A novel nonlinear event-triggered controller is developed, which is based on the random sampled-data. Under the proposed controller, it is found that the Zeno behavior is naturally excluded and the finite-time synchronization of RDCNs is guaranteed. Moreover, by utilizing Lyapunov functional method and the inequality techniques, the finite-time synchronization condition of the RDCNs is derived as well as the finite time is calculated. Finally, numerical simulation results are provided to demonstrate the theoretical results. [ABSTRACT FROM AUTHOR]

Rumor spreading has a profound influence on people’s well-being and social stability. There are many factors influencing rumor spreading. In this paper, we recommended an assumption that among the common mass there are three attitudes towards rumors: to like rumor spreading, to dislike rumor spreading, and to be hesitant (or neutral) to rumor spreading. Based on such an assumption, a Susceptible–Hesitating–Affected–Resistant(SHAR) model is established, which considered individuals’ different attitudes towards rumor spreading. We also analyzed the local and global stability of rumor-free equilibrium and rumor-existence equilibrium, calculated the basic reproduction number of our model. With numerical simulations, we illustrated the effect of parameter changes on rumor spreading, analyzing the parameter sensitivity of the model. The results of the theoretical analysis and numerical simulations illustrated the conclusions of this study. People having different attitudes towards rumors may play different roles in the process of rumor spreading. It was surprising to find, in our research, that people who hesitate to spread rumors have a positive effect on the spread of rumors. [ABSTRACT FROM AUTHOR]

In this paper, we establish two new stochastic switched epidemic models with continuous and impulsive control. The stochastic perturbations are considered for the natural death rate in each equation of the models. Firstly, a stochastic switched S I L I model with continuous control schemes is investigated. By using Lyapunov–Razumikhin method, the sufficient conditions for extinction in mean are established. Our result shows that the disease could be die out theoretically if threshold value R is less than one, regardless of whether the disease-free solutions of the corresponding subsystems are stable or unstable. Then, a stochastic switched S I L I model with continuous control schemes and pulse vaccination is studied. The threshold value R is derived. The global attractivity of the model is also obtained. At last, numerical simulations are carried out to support our results. [ABSTRACT FROM AUTHOR]

In this paper we study spatial quantile regression estimation of multivariate threshold time series models. Bahadur’s representations for our estimators are established, which naturally lead to asymptotic normality of the estimators. Simulations and a real example are used to evaluate the performance of the proposed estimators. [ABSTRACT FROM AUTHOR]

In this paper, a new lattice hydrodynamic model with consideration of the density difference of a lattice’s current density and its anticipative density is proposed. The influence of lattice’s self-anticipative density on traffic stability is revealed through linear stability theory and it shows that lattice’s self-anticipative density can improve the stability of traffic flow. To describe the phase transition of traffic flow, the mKdV equation near the critical point is derived by using nonlinear analysis method. The propagating behavior of density wave in the unstable region can be described by the kink–antikink soliton of the mKdV equation. Numerical simulation validates the analytical results, which shows that traffic jam can be suppressed efficiently by considering lattice’s self-anticipative density in the modified lattice hydrodynamic model. [ABSTRACT FROM AUTHOR]

Abstract: In China, both the mountainous areas and the number of people who live in mountain areas occupy a significant proportion. When production accidents or natural disasters happen, the residents in mountain areas should be evacuated and the evacuation is of obvious importance to public safety. But it is a pity that there are few studies on safety evacuation in rough terrain. The particularity of the complex terrain in mountain areas, however, makes it difficult to study pedestrian evacuation. In this paper, a three-dimensional surface cellular automata model is proposed to numerically simulate the real time dynamic evacuation of residents. The model takes into account topographic characteristics (the slope gradient) of the environment and the biomechanics characteristics (weight and leg extensor power) of the residents to calculate the walking speed. This paper only focuses on the influence of topography and the physiological parameters are defined as constants according to a statistical report. Velocity varies with the topography. In order to simulate the behavior of a crowd with varying movement velocities, and a numerical algorithm is used to determine the time step of iteration. By doing so, a numerical simulation can be conducted in a 3D surface CA model. Moreover, considering residents evacuation around a gas well in a mountain area as a case, a visualization system for a three-dimensional simulation of pedestrian evacuation is developed. In the simulation process, population behaviors of congestion, queuing and collision avoidance can be observed. The simulation results are explained reasonably. Therefore, the model presented in this paper can realize a 3D dynamic simulation of pedestrian evacuation vividly in complex terrain and predict the evacuation procedure and evacuation time required, which can supply some valuable information for emergency management. [Copyright &y& Elsevier]

In this paper we investigate the persistence and extinction of a stochastic epidemic model with a varying population environment in the long-term behavior. Our model consists of two stochastic differential equations: one for the susceptible individuals in which the transmission rate is disturbed by white noise, one for the exposed individuals in which the same perturbation occurs, and one ordinary differential equation in which describes the infective individuals in a varying population environment. We derive sufficient conditions for the extinction and persistence of the epidemic model depending on the constant contact rate. Moreover, we carry out several numerical simulations to illustrate the main results of this contribution. [ABSTRACT FROM AUTHOR]

In this paper, a new lattice model is proposed by considering the optimal estimation of flux difference information. The effect of this new consideration upon the stability of traffic flow is examined through linear stability analysis. Furthermore, a modified Korteweg–de Vries (mKdV) equation near the critical point is constructed and solved by means of nonlinear analysis method, and thus the propagation behavior of traffic jam can be described by the kink–antikink soliton solution of the mKdV equation. Numerical simulation is carried out under periodical condition with results in good agreement with theoretical analysis, therefore, it is verified that the new consideration can enhance the stability of traffic systems and suppress the emergence of traffic jams effectively. [ABSTRACT FROM AUTHOR]

Considering the difference of different individuals’ physical quality and antibody, this paper investigates the epidemic spreading model with the virus mutation. By using the mean-field theory, the epidemic threshold with degree-dependent spreading rate can be theoretical drawn. According to the numerical simulations, we can obtain that the average infected virus version in the BA network is less than the ER network. In addition, if the effective spreading rate is either small or large enough, the average virus version of the whole infected individuals will reduce. However, when the spreading rate takes some proper values, the average infected virus version can greatly increase. Finally, we study how the different initial infected nodes influence the average virus version of the whole infected individuals. The numerical results show that the greater of the initial infected degree, the smaller of the average virus version of the whole infected individuals. [ABSTRACT FROM AUTHOR]

Identifying the most influential individuals spreading ideas, information, or infectious diseases is a topic receiving significant attention from network researchers, since such identification can assist or hinder information dissemination, product exposure, and contagious disease detection. Hub nodes, high betweenness nodes, high closeness nodes, and high k -shell nodes have been identified as good initial spreaders. However, few efforts have been made to use node diversity within network structures to measure spreading ability. The two-step framework described in this paper uses a robust and reliable measure that combines global diversity and local features to identify the most influential network nodes. Results from a series of Susceptible–Infected–Recovered (SIR) epidemic simulations indicate that our proposed method performs well and stably in single initial spreader scenarios associated with various complex network datasets. [ABSTRACT FROM AUTHOR]

With the development of Internet and wireless communication, virtual social networks are becoming increasingly important in the formation of nowadays’ social communities. Topological evolution model is foundational and critical for social network related researches. Up to present most of the related research experiments are carried out on artificial networks, however, a study of incorporating the actual social activities into the network topology model is ignored. This paper first formalizes two mathematical abstract concepts of hobbies search and friend recommendation to model the social actions people exhibit. Then a social activities based topology evolution simulation model is developed to satisfy some well-known properties that have been discovered in real-world social networks. Empirical results show that the proposed topology evolution model has embraced several key network topological properties of concern, which can be envisioned as signatures of real social networks. [ABSTRACT FROM AUTHOR]

Abstract: The study of opinion dynamics, such as spreading and controlling of rumors, has become an important issue on social networks. Numerous models have been devised to describe this process, including epidemic models and spin models, which mainly focus on how opinions spread and interact with each other, respectively. In this paper, we propose a model that combines the spreading stage and the interaction stage for opinions to illustrate the process of dispelling a rumor. Moreover, we set up authoritative nodes, which disseminate positive opinion to counterbalance the negative opinion prevailing on online social networking sites. With analysis of the relationship among positive opinion proportion, opinion strength and the density of authoritative nodes in networks with different topologies, we demonstrate that the positive opinion proportion grows with the density of authoritative nodes until the positive opinion prevails in the entire network. In particular, the relationship is linear in homogeneous topologies. Besides, it is also noteworthy that initial locations of the negative opinion source and authoritative nodes do not influence positive opinion proportion in homogeneous networks but have a significant impact on heterogeneous networks. The results are verified by numerical simulations and are helpful to understand the mechanism of two different opinions interacting with each other on online social networking sites. [Copyright &y& Elsevier]

Abstract: Student dormitories are both living and resting areas for students in their spare time. There are many small rooms in the dormitories. And the students are distributed densely in the dormitories. High occupant density is the main characteristic of student dormitories. Once there is an accident, such as fire or earthquake, the losses will be cruel. Computer evacuation models developed overseas are commonly applied in working out safety management schemes. The average minimum widths of corridor and exit are the two key parameters affecting the evacuation for the dormitory. The effect of varying these two parameters will be studied in this paper by taking a dormitory in our university as an example. Evacuation performance is predicted with the software FDS + Evac. The default values in the software are used and adjusted through a field survey. The effect of varying either of the two parameters is discussed. It is found that the simulated results agree well with the experimental results. From our study it seems that the evacuation time is not in proportion to the evacuation distance. And we also named a phenomenon of “the closer is not the faster”. For the building researched in this article, a corridor width of 3 m is the most appropriate. And the suitable exit width of the dormitory for evacuation is about 2.5 to 3 m. The number of people has great influence on the walking speed of people. The purpose of this study is to optimize the building, and to make the building in favor of personnel evacuation. Then the damage could be minimized. [Copyright &y& Elsevier]

Abstract: The evacuation process of students from a dormitory is investigated by both experiment and modeling. We investigate the video record of pedestrian movement in a dormitory, and find some typical characteristics of evacuation, including continuous pedestrian flow, mass behavior and so on. Based on the experimental observation, we found that simulation results considering pre-movement time are closer to the experimental results. With the model considering pre-movement time, we simulate the evacuation process and compare the simulation results with the experimental results, and find that they agree with each other closely. The crowd massing phenomenon is conducted in this paper. It is found that different crowd massing phenomena will emerge due to different desired velocities. The crowd massing phenomenon could be more serious with the increase of the desired velocity. In this study, we also found the faster-is-slower effect. When the positive effect produced by increasing the desired velocity is not sufficient for making up for its negative effect, the phenomenon of the greater the desired velocity the longer the time required for evacuation will emerge. From the video record, it can be observed that the mass behavior is obvious during the evacuation process. And the mass phenomenon could also be found in simulation. The results obtained from our study are also suitable to all these buildings in which both living and resting areas occupy the majority space, such as dormitories, residential buildings, hotels (restaurants) and so on. [Copyright &y& Elsevier]

Abstract: In this paper, we study the competition model of commercial websites with learning and updating speed, and further analyze the influence of learning and updating speed on the growth of commercial websites from a nonlinear dynamics perspective. Using the center manifold theory and the normal form method, we give the explicit formulas determining the stability and periodic fluctuation of commercial sites. Numerical simulations reveal that sites periodically fluctuate as the speed of learning and updating crosses one threshold. The study provides reference and evidence for website operators to make decisions. [Copyright &y& Elsevier]

Abstract: In this paper, motivated by the thoughts and methods of the mixture of preferential and uniform attachments, we extend the Barabási–Albert (BA) model, and establish a network model with the power-law accelerating growth and the mixture of the two attachment mechanisms. In our model, the number of edges generated by each newly-introduced node is proportional to the power of () of time , i.e., . By virtue of the continuum approach, we have deduced the degree distribution of our model with the extended power-law form . When the number of edges generated by each new node is much greater than the value of , the degree distribution will converge to the power-law form . When is much less than the value of , the degree distribution will converge to the exponential-law form . By virtue of numerical simulations, we also discuss the dependence of the degree distribution on the model’s parameters (where is considered as a constant in the simulations). Finally, we investigate the possible application of our model in the spreading and evolution of epidemics in some real-world systems. [Copyright &y& Elsevier]

Abstract: There are significant differences between rumor spreading and epidemic spreading in social networks, especially with consideration of the mutual effect of forgetting and remembering mechanisms. In this paper, a new rumor spreading model, Susceptible-Infected-Hibernator-Removed (SIHR) model, is developed. The model extends the classical Susceptible-Infected-Removed (SIR) rumor spreading model by adding a direct link from ignorants to stiflers and a new kind of people-Hibernators. We derive mean-field equations that describe the dynamics of the SIHR model in social networks. Then a steady-state analysis is conducted to investigate the final size of the rumor spreading under various spreading rate, stifling rate, forgetting rate, and average degree of the network. We discuss the spreading threshold and find the relationship between the final size of the rumor and two probabilities. Also Runge–Kutta method is used for numerical simulation which shows that the direct link from the ignorants to the stiflers advances the rumor terminal time and reduces the maximum rumor influence. Moreover, the forgetting and remembering mechanisms of hibernators postpone the rumor terminal time and reduce the maximum rumor influence. [Copyright &y& Elsevier]

Abstract: In this paper, the lane reduction bottleneck is investigated using the optimal velocity model, in which two kinds of vehicles (fast and slow) are introduced. The asymmetric lane changing rules in the slowdown section and the lane squeezing behaviors at the bottleneck are taken into account. Under the periodic boundary condition, the numerical simulations are performed. The traffic states change with increasing density. And an interesting phenomenon of ratio inversion appears. When the current saturates, the headway and velocity discontinuously vary with the position. In addition, traffic patterns and the phase transition points depend greatly on the speed limit and the length of the slowdown section. [Copyright &y& Elsevier]

Abstract: In this paper, we study a stochastic predator–prey model with Beddington–DeAngelis type functional response and logistic growth for predators. The deterministic model is already well-studied and we recall some important results here. We construct the stochastic model from the deterministic model by introducing multiplicative noise terms into the growth equations of prey and predator populations. For the stochastic model, we show that the system admits unique positive global solution starting from the positive initial value. Then we prove that the system is strongly persistent in mean when the intensity of environmental forcing is less than some threshold magnitudes. Finally, we show that the system has a stationary distribution under certain parametric restrictions. Numerical simulations are carried out to substantiate the analytical results. [Copyright &y& Elsevier]

Abstract: This paper investigates the analytical and numerical solutions to wide moving jams in traffic flow. Under the framework of the Lagrange coordinates, a semi-discrete model and a continuum model correlate with each other, in which the former model approaches the latter as the increment in the former model vanishes. This implies that the solution to a wide moving jam in the latter model, which can be analytically derived using the known theory, can be conceivably taken as an approximation to that of the former model. These results were verified through numerical simulations. Because a detailed understanding of the traffic phase “wide moving jam” is very important for the further development of Kerner’s three-phase traffic theory, this study helps to explain the empirical features of traffic breakdown and resulting congested traffic patterns that are observed in real traffic. [Copyright &y& Elsevier]

Abstract: In order to describe car following behavior in real world, this paper presents a non-lane-based car following model by incorporating the effects of the lane width in traffic. The stability condition of the model is obtained by using the linear stability theory. And numerical simulation is carried out to validate the analytic results. The property of the model is investigated, and it is found that the proposed model can describe the phase transition of traffic flow and estimate the evolution of traffic congestion. The results implied that incorporating the lane width effects in car following model not only stabilize traffic flow and suppress the traffic jam, but also lower critical headway and increase capacity. Thus, the lateral separation effects greatly enhance the realism of car following models. [ABSTRACT FROM AUTHOR]

Abstract: We generate a porous structure by computer simulation in (2+1) dimension using a bidisperse ballistic deposition model. Particles of two different sizes are deposited randomly creating a porous bulk bounded by a highly irregular upper surface. The structure of the interface is connected to the homogeneity of the bulk produced. In this paper we study the development of the dynamic interface as a function of the proportion of the two types of particles. is the probability of choosing the larger grains and that of the smaller grains. In the limit , the model is identical to the random deposition (RD) model whereas in the limit , the model is similar, but not identical to the ballistic deposition (BD) model. For all values greater than 0, the growth exponent changes across a transition time . increases asymptotically from 0 to infinity as tends to 0, from 1. The roughness and dynamic exponents are also determined as a function of . We conclude that to simulate a homogeneous medium with a uniform porosity throughout, it is necessary to grow the system for a time . [Copyright &y& Elsevier]