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In this paper, we propose a cellular automaton model to investigate the traffic flow characteristics in the traffic circle system with adaptive traffic lights control. The traffic flow in the circulating lane was evaluated and depending on it the traffic lights lit red in the entry lanes to reduce the coming traffic. The density and the satisfaction rate were used as feedback to control the traffic flow in the circulating lane. It is found that both parameters (i.e. the density and the satisfaction rate in the circulating lane), if they are used as a criterion to control the coming traffic from entry lanes, promote the throughput in the traffic circle system. Traffic flow for the traffic circle system without using the traffic lights was investigated. In this case, we find that the traffic flow in the system is characterized by three phases, namely, gridlock, congestion, and free flow. The gridlock phase is predominant over the other phases. Furthermore, with the use of the adaptive traffic lights, the gridlock phase has vanished and the maximum current, jammed, and congestion phases take place. The density criterion shows good performance as compared with the satisfaction rate criterion in terms of the lengths of the red cycle. The capacity is also investigated. The space-time configurations were given to understand the microscopic interaction between vehicles. [ABSTRACT FROM AUTHOR]

In this paper, we propose a cellular automaton model to simulate traffic flow controlled by a series of traffic lights. The synchronized traffic light and the green wave light strategies were investigated. The spatiotemporal diagrams, energy dissipation, and CO2 emission of the system were presented. Our simulations are conducted to clarify the difference between both strategies and their effects on the traffic flow and the CO2 emission. We found that the traffic flow depends mainly on the strategy used for managing the traffic lights as well as on the parameters of the traffic lights, namely the cycle length, the number of traffic lights and the length of the system. The fundamental diagram has barely the same characteristics for both methods and it depends on the combination of the parameters of the system. We find that the green wave is more convenient for the management of a series of traffic lights than the synchronized control strategy in terms of throughput, especially for large-sized systems. Unlike in terms of CO2 emission and energy dissipation, both control strategies outperform each other depending on the density regions and the parameters of the system. Finally, we investigate the effect of both cycles (i.e. red and green) for the synchronized control method on the CO2 emission. It is found that the green cycle generates often a series of acceleration events that increase CO2 emission. [ABSTRACT FROM AUTHOR]

In traffic networks, it is quite important to assign proper packet delivering capacities to the routers with minimum cost. In this respect, many allocation models based on static and dynamic properties have been proposed. In this paper, we are interested in the impact of limiting the packet delivering capacities already allocated to the routers; each node is assigned a packet delivering capacity limited by the maximal capacity of the routers. To study the limitation effect, we use two basic delivering capacity allocation models; static delivering capacity allocation (SDCA) and dynamic delivering capacity allocation (DDCA). In the SDCA, the capacity allocated is proportional to the node degree, and for DDCA, it is proportional to its queue length. We have studied and compared the limitation of both allocation models under the shortest path (SP) routing strategy as well as the efficient path (EP) routing protocol. In the SP case, we noted a similarity in the results; the network capacity increases with increasing . For the EP scheme, the network capacity stops increasing for relatively small packet delivering capability limit for both allocation strategies. However, it reaches high values under the limited DDCA before the saturation. We also find that in the DDCA case, the network capacity remains constant when the traffic information available to each router was updated after long period times . [ABSTRACT FROM AUTHOR]

In this paper, we present a cellular automata model to depict the traffic characteristics at such a nonsignalized -shaped intersection in the presence of pedestrian crossings. The vehicular traffic flow characteristics with different parameters are studied. Throughput, phase diagrams, space-time and density profiles are built to point various traffic states and the phase transition features. The principal finding of the simulation are as follows: (1) The presence of crossing pedestrians has a significant influence on the vehicular traffic and the system performance, (2) The intersection capacity has a close relevance with the state of the weaving section. The smaller the interactions are at the weaving section, the higher the capacity and (3) In order to have a higher system ability, the crosswalk location should not be far from the yield line of the weaving section. [ABSTRACT FROM AUTHOR]

In this paper, a new model of the interdependent complex network is proposed, based on two assumptions that (i) the capacity of a node depends on its degree, and (ii) the traffic load depends on the distribution of the links in the network. Based on these assumptions, the presented model proposes a method of connection not based on the node having a higher degree but on the region containing hubs. It is found that the final network exhibits two kinds of degree distribution behavior, depending on the kind and the way of the connection. This study reveals a direct relation between network structure and traffic flow. It is found that the point of transition between the free flow and the congested phase depends on the network structure and the degree distribution. Moreover, this new model provides an improvement in the traffic compared to the results found in a single network. The same behavior of degree distribution found in a BA network and observed in the real world is obtained; except for this model, the transition point between the free phase and congested phase is much higher than the one observed in a network of BA, for both static and dynamic protocols. [ABSTRACT FROM AUTHOR]

Using cellular automata (CA) Nagel–Schreckenberg (NaSch) model, we numerically study the probability Pac of the occurrence of car accidents at nonsignalized intersection when drivers do not respect the priority rules. We also investigated the impact of mixture lengths and velocities of vehicles on this probability. It is found that in the first case, where vehicles distinguished only by their lengths, the car accidents start to occur above a critical density ρc. Furthermore, the increase of the fraction of long vehicles (FL) delays the occurrence of car accidents (increasing ρc) and increases the risk of collisions when ρ > ρc. In other side, the mixture of maximum velocities (with same length for all vehicles) leads to the appearance of accidents at the intersection even in the free flow regime. Moreover, the increase of the fraction of fast vehicles (Ff) reduces the accident probability (Pac). The influence of roads length is also studied. We found that the decrease of the roads length enhance the risk of collision. [ABSTRACT FROM AUTHOR]

Optimal allocation of vaccine doses is a major challenge faced by the health authorities especially in the case of an ever-growing pandemic expansion and a limited supply availability. Based on a spatio-temporal compartmental virus propagation model applied to the case of SARS-CoV-2 virus, we investigate a layered vaccine allocation strategy for the subpopulations of a given country or a geographical region based on the prevalence of susceptible individuals as a prioritization metric. Our findings show that a relaxed layered allocation prioritization, where a maximum of regions benefit from vaccine doses is more effective in controlling the epidemic than a strict prioritization, focused only on the few most prioritized regions. These results are consistent among different vaccine rollout speeds for various limiting values of the priority list. [ABSTRACT FROM AUTHOR]

Connected vehicles (CVs) have led to innovative changes in the transportation field. In this wise, an extended CA model was established incorporating the CVs and regular vehicles to investigate a roundabout traffic flow under the open boundary condition. The throughput and the phase diagrams of the system in the ( α 1 , α 2 ) area is constructed in both cases: with and without CVs. The density profile and the capacity are also calculated. The simulation findings show that CVs presentation changes the traffic dynamics, enhancing roundabout capacity in accordance with the CVs penetration rate. Furthermore, it is found that roundabout size plays a dominant role in its performance where it suggests that the midsized roundabouts operate more optimally. Another relevant aspect is the short sized of Splitter Island shows a better performance. Moreover, the traffic dynamics is negatively (resp. positively) correlated to the probability of displaying indicator P ind as well as the probability of aggressive driving behavior of regular vehicles (resp. the cooperation probability P cop ). [ABSTRACT FROM AUTHOR]

We propose a traffic flow model which takes into account the disorder in the length and the maximal speed of cars. Using cellular automaton model in parallel dynamics we have studied the behavior of traffic flow, especially the condition of formation (active phase) and the dissociation (absorbing phase) of platoons. It is found that the transition from active to absorbing phase depend on the length of the slow vehicles L2. Indeed, the transition is discontinuous for L2 = 1 and continuous when L2 > 1. In the later case, the critical exponent is calculated near the transition density, and the space-time diagram shows the presence of the two phases. Furthermore, we have found that the fundamental diagram exhibit a plateau which depend on the size of the system. [ABSTRACT FROM AUTHOR]

Tollbooths are used to collect tolls and to control traffic flow. However, the presence of these tollbooths will slow down traffic, especially in heavily traveled roads. As a consequence, drivers and goods will spend more time and fuel waiting in a long queue. Unfortunately, there are a few papers in the literature, which have been addressed the effect of tollbooths on the traffic flow; whereas in this paper is, the properties of traffic flow inside the tollbooths are investigated. The proposed cellular automaton traffic model, with open boundaries, is based on some changing lane rules, which are inspired on the situations inside the toll plaza. The vehicles enter the plaza with an injecting rate α, and they leave with an extracting rate β, which is inversely proportional to the time service Tw. The simulation results show the existence of three phases in the phase diagram (α, β), namely: the low density phase, the congested phase, and the jamming phase. Furthermore, it is found that the vehicles does not spend the same time Tm in the plaza, even if they have the same time service. This analysis states clearly that the existence of the congested phase and the fluctuation Tm are due to the non-zero values of the probability P of changing the lane. Such phenomena disappear when P = 0, i.e., the drivers move without changing their lane. In other words, the human behavior (spontaneous changing lanes) is responsible for the congestion observed in the tollbooth. [ABSTRACT FROM AUTHOR]

We have numerically investigated the effect of the delay times τf and τs of a mixture of fast and slow vehicles on the fundamental diagram (the current-density relation) of the optimal velocity model. The optimal velocity function of the fast cars depends not only on the headway of each car but also on the headway of the immediately preceding one. It is found that the small delay times have almost no effects, while, for sufficiently large delay time τs, the current profile displays qualitatively five different forms, depending on τf, τs and the fractions df and ds of the fast and slow cars, respectively. The velocity (current) exhibits first-order transitions at low and/or high densities, from freely moving phase to the congested state, and from congested state to a jamming one, respectively. The minimal current appears in intermediate values of τs. Furthermore, there exist a critical value of τf above which the metastability and hysteresis appear. The spatial-temporal traffic patterns near the congested-jamming first-order transition is also presented. [ABSTRACT FROM AUTHOR]

The effect of the random quantum transverse field Ω on the tricritical behavior of the spin-1 Blume–Emery–Griffiths (BEG) model is studied using an effective field theory. It is found that the tricritical behavior depends on both the biquadratic interaction K, single-ion anisotropy Δ and the concentration p of the disorder of Ω. Indeed, there exists a special value p1 of the probability p below which the tricritical behavior disappears. In addition, at sufficiently low temperatures, the system exhibits long-range order accompanied by the tricritical behavior below a special value p2 of the probability p. [ABSTRACT FROM AUTHOR]

The structural, electronic, magnetic, magnetocaloric, and thermoelectric properties of the SrXO3 (X = Mn and Fe) perovskite compounds were investigated using first-principles calculations. It was observed that the SrXO3 compounds are G-anti-ferromagnetic perovskites with partial magnetic moment with a value of 2.7 μ B and 2.4 μ B for Mn-3d and Fe-3d orbitals for SrMnO3 and SrFeO3, respectively. Moreover, by using Monte Carlo simulation (MCs) combined with the Metropolis algorithm, the calculated coupling interactions between the magnetic atoms Mn–Mn and Fe–Fe are J 1 Mn = 5. 1 7 meV and J 2 Mn = − 0. 6 meV for SrMnO3, J 1 Fe = 3. 4 4 meV and J 1 Fe = − 0. 4 meV for SrFeO3, respectively. Furthermore, a significant magnetocaloric effect (MCE) was observed around the Néel temperature of T N Mn = 2 6 0 K (for SrMnO3) and T N Fe = 1 3 4 K (for SrFeO3), and the maximal simulated magnetic entropy and relative cooling power values of all the studied compounds are found to be 100 J/kg (for SrMnO3) and 110 J/kg (for SrFeO3), respectively, with an applied magnetic field of H = 4. 0 T. These results are in complete agreement with the experimental results and more specifics than other theoretical calculations. Hence, SrXO3 compounds are considered promising candidates for magnetic refrigeration at low temperature. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the impact of connected and autonomous vehicles (CAVs) on traffic flow under various parameters. For this purpose, we propose a mixed CAV and conventional vehicle (CV) model to investigate a bidirectional two-lane traffic flow under the periodic boundary condition. The traffic flux and the phase diagrams of the system in the ( ρ 1 , ρ 2 ) area are constructed in both cases: with and without CAVs. The overtaking frequency is also calculated. The simulation findings show that the traffic capacity is greatly enhanced with the increase in the CAV penetration ratio. Owing to the cooperative driving strategy, with the increase in penetration ratio of the CAV, the portion of smooth overtaking is boosted. Furthermore, it is found that the traffic throughput is positively correlated to the speed limit of the fast vehicle where the flux increases as V max − F increases. Also, even if there is a low rate of slow moving vehicles in the system, it will have an appreciable and a significant negative influence. [ABSTRACT FROM AUTHOR]

In this paper, we examine the impact of vehicles executing a full turn or U-turn in a single-lane roundabout system using a cellular automaton model. We investigate how increasing the number of these U-turning vehicles affects traffic flow characteristics and energy dissipation. Our findings reveal that as the prevalence of U-turning vehicles rises, the phase diagram undergoes significant changes; the maximum current phase expands, detrimentally impacting the free flow and congestion phases, while giving rise to a jamming phase. This shift results in a gradual increase in capacity at circulating lanes and a steady decline at entry/exit lanes. We also explore the role of aimless vehicles — those circulating without a fixed destination. As the proportion of such vehicles augments, it fosters an enlargement of the maximum current phase at the expense of the free flow and congestion phases. Furthermore, these vehicles influence energy dissipation across the three lanes of a roundabout. Significantly, we elucidate that variations in the percentage of these specific vehicular groups critically affect CO2 emissions. Our research unravels vital insights into optimizing roundabout management to enhance traffic flow and reduce environmental impact. [ABSTRACT FROM AUTHOR]

Researchers are working on perovskites for photovoltaic applications due to their low cost and excellent power conversion efficiency. Our investigation has focused on analyzing the effects of hydrostatic strain on the structural, electronic, optical and thermoelectric properties of CsSnBr3. The calculated structural properties and enthalpy of formation imply that these structures are stable under different strain conditions. Our investigation shows that the CsSnBr3 compound is a direct semiconductor with an electronic band gap of 1.272 eV, which can be tuned from 0.604 eV to 1.823 eV under different strain conditions. As the compressive strain increases, the light absorption spectrum of CsSnBr3 undergoes a red shift, causing a prolongation of the light absorption edge. The thermoelectric properties show that CsSnBr3 is a p-type semiconductor. Our findings indicate that the CsSnBr3 material is highly suitable for photovoltaic applications. [ABSTRACT FROM AUTHOR]

In this study, we performed extensive Monte Carlo simulations to comprehensively analyze the magnetic properties of a single-layer MXene-like lattice. Our investigation involved the exploration of transition temperatures and the behavior of hysteresis cycles, all influenced by a series of key physical parameters. Additionally, we carefully mapped the magnetization as a function of temperature and crystal field, introducing variations in the exchange coupling to unveil their impact on the transition temperature. Furthermore, we investigated the behavior of hysteresis loops, complexly dissecting their responses to changes in exchange coupling, temperature, and crystal field. Significantly, our results highlight the central role of the crystal field in the formation of magnetization plateaus, thus providing promising avenues for applications in nanotechnology and advanced memory storage systems. [ABSTRACT FROM AUTHOR]

In this paper, we propose a stochastic cellular automata model to study the traffic behavior at a single-lane roundabout. Vehicles can enter the interior lane or exit from it via intersecting lane, the boundary conditions are stochastic. The traffic is controlled by a self-organized scheme. It has turned out that depending on the rules of insertion to the roundabout, five distinct traffic phases can appear, namely, free flow, congestion, maximum current, jammed and gridlock. The transition between the free flow and the gridlock is forbidden. The density profiles are used to study the traffic pattern at the interior lane of the roundabout. In order to quantify the interactions between vehicles in the interior lane of the roundabout, the velocity correlation coefficient (VCC) is also studied. Besides, the spatiotemporal diagrams corresponding to the entry/exit lanes are derived numerically. Furthermore, we have investigated the effect of displaying signal (, as the decreases, the maximum current increases at the expense of the free flow and the jamming phase. Finally, we have investigated the effect of the braking probability on the interior lane of the roundabout. We have found that the increase of raises the spontaneous jam formation on the ring. Thus, enlarges the maximum current and the jamming phase while the free flow phase decreases. [ABSTRACT FROM AUTHOR]

The speed limit signs can be used to enhance traffic safety, nevertheless, the large differences between the speed of vehicles provoked by the speed limit zone (SLZ) may increase the dissipation of energy caused by the deceleration of vehicles. In this paper, the effect of the SLZ on traffic flow and energy dissipation is investigated based on a cellular automaton model that considers the three traffic phases (free flow, synchronized flow and wide moving jams). It is found that the throughput and the energy dissipation depend strongly on the length of the SLZ as well as on the speed adopted inside the SLZ. The microscopic effect of the SLZ is also studied. The dependence of the density and the length of platoons induced by the SLZ were evaluated. The characteristic of the traffic flow can be also evaluated with the energy dissipation. For high densities, the effect of the SLZ becomes seldom on the flow, however, the energy dissipation shows salient features, which can be used as an indicator of traffic phases. [ABSTRACT FROM AUTHOR]

In this paper, using the Nagel-Schreckenberg model, we numerically investigate the probability of entering/circulating car accidents to occur at single-lane roundabout under the expanded open boundary. The roundabout consists of N on-ramps (respectively, off-ramps). The boundary is controlled by the injecting rates and the extracting rate . The simulation results show that, depending on the injecting rates, the car accidents are more likely to happen when the capacity of the rotary is set to its maximum. Moreover, we found that the large values of rotary size L and the probability of preferential are reliable to improve safety and reduce accidents. However, the usage of indicator, the increase of and/or N provokes an increase of car accident probability. [ABSTRACT FROM AUTHOR]

In this paper, using Nagel-Schreckenberg model we study the on-ramp system under the expanded open boundary condition. The phase diagram of the two-lane on-ramp system is computed. It is found that the expanded left boundary insertion strategy enhances the flow in the on-ramp lane. Furthermore, we have studied the probability of the occurrence of car accidents. We distinguish two types of car accidents: the accident at the on-ramp site (Prc) and the rear-end accident in the main road (Pac). It is shown that car accidents at the on-ramp site are more likely to occur when traffic is free on road A. However, the rear-end accidents begin to occur above a critical injecting rate αc1. The influence of the on-ramp length (LB) and position (xC0) on the car accidents probabilities is studied. We found that large LB or xC0 causes an important decrease of the probability Prc. However, only large xC0 provokes an increase of the probability Pac. The effect of the stochastic randomization is also computed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a pair-dependent rejection rate of packet information between routers in the framework of the minimal traffic model applied to scale-free networks. We have shown that the behavior of the transition point from the phase where the system balances the inflow of new information packets with successful delivery of the old ones to the congested phase depends on the underlying mechanism of packet rejection. It is possible to achieve larger values for the critical load by varying the rejection of the packets issued from a given node by its neighbors. We have proposed an asymmetric protocol, where we found the existence of a whole interval where the packet rejection is strongly beneficial to the overall performance of the system. We have also shown that for the dynamic protocol, the transition point is shifted toward higher values permitting the network to handle more traffic load, despite the fact that the critical load decreases when increasing the rejection parameter. [ABSTRACT FROM AUTHOR]

The correlation between the velocity of two successive vehicles as a function of time headway is studied in the one-dimensional cellular automata (CA) NaSch model within parallel dynamic update. It is found that a strong correlation occurs in short time headway. The behavior of the correlation velocity as a function of the car density in different traffic states is also investigated. Moreover, our study is also extended to a more complicated situation where the two vehicles are separated by a number n of other vehicles. It is shown that the velocity correlation coefficient depends strongly on the number n of vehicles in between and on their positions. [ABSTRACT FROM AUTHOR]

In this paper, we study the probability of car accidents in the modified Nagel–Schreckenberg (mNaSch) under the periodic boundary condition. In order to understand the quality of interaction between vehicles in each phase of the mNaSch, the velocity correlation coefficients were investigated. The effect of the evacuation of damaged vehicles was also studied. The fundamental diagram of the system is constructed in both cases with and without the evacuation. We found that the synchronized phases in the mNaSch are manifested into two aspects. In the first phase, the velocity correlation coefficients are zero where all vehicles move at the same speed. Hence, in the other phase, the speed of vehicles shows a synchronization as the form of clusters of moving vehicles where two speeds predominate simultaneously and the velocity correlation coefficients are higher. In addition, the car accidents in the modified mNaSch depend strongly on the initial configuration especially, if we consider those car accidents really happening in the system. The evacuation of damaged vehicles enhances the traffic situation and qualitatively changes the traffic phases in the mNaSch. [ABSTRACT FROM AUTHOR]

In order to understand and achieve an optimal functioning in real traffic systems, the problem of congestion in complex networks takes an important place in many recent researches. In this paper, we study the effect of different types of interconnections between two scale free networks on the traffic flow. Two interconnection strategies are used: in the first, we create links between nodes chosen at random from the two subnets G 1 and G 2 and, while in the second one, we link nodes selected among the hubs of the subnets. The resulting network G is under a new routing strategy inspired from the minimal traffic model introduced in [D. De Martino, Phys. Rev. E79, 015101 (2009); S. Lamzabi, S. Lazfi, H. Ez-Zahraouy, A. Benyoussef, A. Rachadi and S. Ziti, Int. J. Mod. Phys. C25, 1450019 (2014)]. We find that in case of this routing method, the interconnection pattern has no effect on the results. Further, to control the exchange of packets between the subnets, we propose two adjusting parameters α 1 and α 2 . The study of the variation of these parameters shows that the optimal network capacity is obtained when the two subnets are allowed to exchange data more openly. [ABSTRACT FROM AUTHOR]

In this paper, we propose a cellular automata model to study the energy dissipation in the roundabout system. The energy dissipation and the phase diagram of the system in the space (α , β) are constructed. The energy dissipation profile (SE d (i)), and the effect of the rate γ (i.e., the rate of vehicles with no aimed exit point) and the probability P exit of choosing the next exit point to leave the circulating lane on the energy dissipation are shown. The simulation results show that the energy dissipation explains the nature of the phases, the quasi-free-flow (Q-FF) phase take place on the free flow phase because some vehicles decelerate at the entry point. Likewise, the results also indicate that the energy dissipation takes small values with the increases of the two probability γ and P exit which enhance the environmental statutes of the roundabout system. [ABSTRACT FROM AUTHOR]

Using the cellular automata Nagel–Schreckenberg (NaSch) model, we numerically study the impact of traffic lights on the probability of car accidents ( P ac ) at the intersection of two roads. It is found that, the probability P ac is more stable with variation of the green light (T) when the symmetric lights are adopted. Moreover, simulation results show the existence of a critical time T c , below which (T < T c ) P ac increases as the injection rate (α) increases, however, above which (T > T c ) the growing of α has for effect the decrease of P ac . Furthermore, the decrease of P ac is almost always accompanied by a loss of the flux, especially with asymmetrical lights. To overcome this problem, we proposed a strategy that can greatly increase the flux and keep the probability P ac as small as possible, especially for the low and high injection rates. [ABSTRACT FROM AUTHOR]

Despite the reality of traffic prioritization in real networks as the internet, this has almost been ignored in designed routing protocols. In this work, we propose a priority policy where packets are prioritized according to their destination. This procedure is applied to a fraction f of nodes; packets are classified as High Priority if their destinations are among the fraction f, otherwise the packets are treated as Low Priority. Using numerical simulation we found that the prioritization of nodes with high degree (hubs) is always more efficient than the prioritization of nodes with small degree or the random prioritization of nodes. Moreover, we observed three regimes based on the prioritized fraction f in the network: the first one is characterized by an improvement of the High Priority Traffic (HPT) flow without any degradation of the flow of the Low Priority Traffic (LPT). In the second regime, the HPT gains some performance at the expense of a loss of the performance in the LPT flow. While in the last regime the LPT experiences a low performance without any noticeable improvement in HPT compared to the normal flow. [ABSTRACT FROM AUTHOR]

Various feedback strategies are proposed to improve the traffic flow. However, most of these works did not take road safety into consideration. In this paper, we studied the impact of four feedback strategies on the probability of rear-end collisions ( P ac ). We proposed a new feedback strategy named Accidents Coefficient Feedback Strategy (ACFS) in which dynamic information can be generated and displayed on a board at the entrance of two-route scenario with intersection to help drivers to choose the appropriate road. This new strategy can greatly improve road safety and make the flow smooth as possible at the same time. Moreover, the impact of the intersection and boundary rates (α and β) on P ac is also studied. [ABSTRACT FROM AUTHOR]

Using the Nagel-Schreckenberg model, we investigate the flow characteristics in a traffic circle system, where the entry lanes are controlled by traffic lights operating in a fixed-time ( T ). We considered four different strategies to control traffic coming from N entry lanes. We found that depending on the strategy used, four distinct traffic phases can appear in the circulating lane of the traffic circle, namely free flow, congestion, maximum current, and gridlock. Also, we investigate the origin of the gridlock phase in both cases (i.e. with/without traffic lights). Furthermore, the lengths of queues of stopped vehicles in the entry lanes were studied. We found that the traffic flow behavior on the exit/entry lanes depends strongly on the flow characteristics at the circulating lane as well as traffic lights strategy. To improve the operation of the traffic circle system, we have studied the time delay between the traffic lights to switch where all entry lanes go red, which allowing vehicles to clear the circulating lane. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations within the Korringa-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA), the structural, optical and magnetic properties of rare-earth nitride HoTMN doped with transition metal (TM) atoms (Ti, V, Cr, Mn, Co and Ni) are investigated as a function the generalized gradient approximation and self-interaction correction (GGA-SIC) approximation. The optical properties are studied in detail by using ab-initio calculations. Using GGA-SIC we have showed that the bandgap value is in good agreement with the experimental value. Using GGA-SIC approximation for HoN, we have obtained a bandgap of 0.9 eV. Some of the dilute magnetic semiconductors (DMS) like HoTMN under study exhibit a half-metallic behavior, which makes them suitable for spintronic applications. Moreover, the optical absorption spectra confirm the ferromagnetic stability based on the charge state of magnetic impurities. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the effect of neighbors on the infection of packets by computer virus in the SI and SIR models using the minimal traffic routing protocol. We have applied this model to the Barabasi-Albert network to determine how intrasite and extrasite infection rates affect virus propagation through the traffic flow of information packets in both the free-flow and the congested phases. The numerical results show that when we change the intrasite infection rate while keeping constant the extrasite infection rate , we get normal behavior in the congested phase: in the network, the proportion of infected packets increases to reach a peak and then decreases resulting in a simultaneous increase of the recovered packets. In contrast, when the intrasite infection rate is kept fixed, an increase of the extrasite infection rate results in two regimes: The first one is characterized by an increase of the proportion of infected packets until reaching some peak value and then decreases smoothly. The second regime is characterized by an increase of infected packets to some stationary value. [ABSTRACT FROM AUTHOR]

The increase of the use of the Internet networks favors the spread of viruses. In this paper, we studied the spread of viruses in the scale-free network with different topologies based on the Susceptible-Infected-External (SIE) model. It is found that the network structure influences the virus spreading. We have shown also that the nodes of high degree are more susceptible to infection than others. Furthermore, we have determined a critical maximum value of node degree , below which the network is more resistible and the computer virus cannot expand into the whole network. The influence of network size is also studied. We found that the network with low size is more effective to reduce the proportion of infected nodes. [ABSTRACT FROM AUTHOR]

In this paper, we propose a stochastic cellular automata (CA) model to study traffic dynamic at a single-lane traffic circle of entry/exit points. The boundaries are controlled by the injecting rates , and the extracting rate . Both the cases with and without the splitter islands of width are considered. The phase diagrams in the space are constructed and the density profiles are also investigated. The variation of the phase diagram with the traffic circle size , the number of entry point , and the time needed for drivers to change their exit willingly is studied. The results show that the phase diagram in both cases consists essentially of three phases namely free flow, congestion and gridlock. However, the large sized traffic circle shows better performance in the free flow phase, in contrary, the increase of enlarges the congestion and the gridlock phases. We have also found that the decrease of enhances the traffic flow situation in the traffic circle. Furthermore, as the increases, the free flow phase enlarges while the congestion and gridlock ones shrink. [ABSTRACT FROM AUTHOR]

For the purposes of optimizing traffic flow composed of different types of vehicles, it is important to understand the interactions between them. This paper proposes a cellular automata model to investigate a bidirectional two-lane traffic flow under the periodic boundary condition. The vehicle flux and the phase diagrams of the system in the () space are constructed by applying two different overtaking models (symmetric, asymmetric). The inter-lane correlation and the overtaking frequency are also studied. The simulation results show that the variation of the density of one lane has an apparent influence on the traffic of the adjacent lane. Furthermore, it is found that the phase diagram on both models is classified into several regions. Thus, for the symmetric model, as the overtaking probability increases, the traffic on the system becomes better. Likewise, the results also indicate that the asymmetric model can effectively enhance the traffic capacity and alleviate the congested state. [ABSTRACT FROM AUTHOR]

Using numerical simulations, we investigate the effects of the connectivity and topologies of network on the quality of transport between connected scale free networks. Hence, the flow as the electrical conductance between connected networks is calculated. It is found that the conductance distribution between networks follow a power law where is the exponent of the global Network of network, we show that the transport in the symmetric growing preferential attachment connection is more efficient than the symmetric static preferential attachment connection. Furthermore, the differences of transport and networks communications properties in the different cases are discussed. [ABSTRACT FROM AUTHOR]

Using the extended Nagel-Schreckenberg (NS) model, we numerically study the impact of the heterogeneity of traffic with speed limit zone (SLZ) on the probability of occurrence of car accidents . SLZ in the heterogeneous traffic has an important effect, typically in the mixture velocities case. In the deterministic case, SLZ leads to the appearance of car accidents even in the low densities, in this region increases with increasing of fraction of fast vehicles . In the nondeterministic case, SLZ decreases the effect of braking probability in the low densities. Furthermore, the impact of multi-SLZ on the probability is also studied. In contrast with the homogeneous case [X. Li, H. Kuang, Y. Fan and G. Zhang, Int. J. Mod. Phys. C 25 (2014) 1450036], it is found that in the low densities the probability without SLZ is low than with multi-SLZ . However, the existence of multi-SLZ in the road decreases the risk of collision in the congestion phase. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new model for computer virus attacks and recovery at the level of information packets. The model we propose is based on one hand on the susceptible-infected (SI) and susceptible-infected-recovered (SIR) stochastic epidemic models for computer virus propagation and on the other hand on the time-discrete Markov chain of the minimal traffic routing protocol. We have applied this model to the scale free Barabasi-Albert network to determine how the dynamics of virus propagation is affected by the traffic flow in both the free-flow and the congested phases. The numerical results show essentially that the proportion of infected and recovered packets increases when the rate of infection and the recovery rate increase in the free-flow phase while in the congested phase, the number of infected (recovered) packets presents a maximum (minimum) at certain critical value of characterizing a certain competition between the infection and the recovery rates. [ABSTRACT FROM AUTHOR]