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1.
李克平  高自友 《中国物理快报》2004,21(11):2120-2123
We propose a new cellular automation (CA) traffic model that is based on the car-following model. A class of driving strategies is used in the car-following model instead of the acceleration in the NaSch traffic model. In our model, some realistic driver behaviour and detailed vehicle characteristics have been taken into account, such as distance-headway and safe distance, etc. The simulation results show that our model can exhibit some traffic flow states that have been observed in the real traffic, and both of the maximum flux and the critical density are very close to the real measurement. Moreover, it is easy to extend our method to multi-lane traffic.  相似文献   

2.
The de Sitter special relativity on the Beltrami-de Sitter-spacetime and Snyder's model in the momentum space can be combined together with an IR-UV duality to get the complete Yang model at both classical and quantum levels, which are related by the proposed Killing quantization. It is actually a special relativity based on the principle of relativity of three universal constants (c, ρp, R).  相似文献   

3.
We introduce a two-species symbiosis-driven growth model, in which two species can mutually benefit for their monomer birth and the self-death of each species simultaneously occurs. By means of the generalized rate equation, we investigate the dynamic evolution of the system under the monodisperse initial condition. It is found that the kinetic behaviour of the system depends crucially on the details of the rate kernels as well as the initial concentration distributions. The cluster size distribution of either species cannot be scaled in most cases; while in some special cases, they both consistently take the universal scaling form. Moreover, in some cases the system may undergo a gelation transition and the pre-gelation behaviour of the cluster size distributions satisfies the scaling form in the vicinity of the gelation point. On the other hand, the two species always live and die together.  相似文献   

4.
We extend the T violating model of the paper on ``Hidden symmetry of the CKM and neutrino-mapping matrices" by assuming its T-violating phases χ and χ to be large and the same, with χ=χ. In this case, the model has 9  相似文献   

5.
Based on the Pomeron exchange model, elastic production of φ meson in electron-proton interaction is investigated with both linear and non-linear Pomeron trajectories. The numerical calculations of the differential cross section for e p → e‘ p φ are performed. The theoretical predictions show that the dependence of the differentialcross section on virtual photon virtuality, Q2, is of moderation, the change of the energy scale parameter so causes moderate effect on the differential cross section, and the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, in particular, at small momentum transfer region | t |≤ 0.2 GeV2.  相似文献   

6.
The effect of surface delta-interaction (SDI) in nucleon-pair shell model truncated to an SD-subspace is studied. The results show that with the single-particle level splitting fully taken into account, for realistic SDI strength, the surface delta-interaction also enhance the E2 and M1 transitions of low-lying states.  相似文献   

7.
8.
A dynamical model of low-frequency-pulsed electron-stimulated desorption is developed. The characteristic of desorbed gas flow is taken as an exponential function, and can be degenerated to a triangular and square wave.The transient pressure is given according to the gas flow of desorbing gas and vacuum system parameters,including the pumping speed and the system volume. Although the mathematical model is deduced from the electron-stimulated desorption, it can be applied to other similar processes of intermittent desorption.  相似文献   

9.
The difference of spectral statistics properties between single-j and two-j shell models has been studied in the frame of the cranking model.The results show that the system becomes more regular when single-j space (i13/2) is replaced by a two-j shell(g7/2 d5/2),although the basis size of the configuration space is unchanged.However, the degres of chaos of the system changes slightly when configuration space is enlarged by extending the single-j shell (i13/2) to two-j(i13/2 g9/2) shell.  相似文献   

10.
Based on the Pomeron exchange model, elastic production of φ meson in electron-proton interaction is investigated with both linear and non-linear Pomeron trajectories. The numerical calculations of the differential cross section for e+p→e' +p+ φ are performed. The theoretical predictions show that the dependence of the differential cross section on virtual photon virtuality, Q^2, is of moderation, the change of the energy scale parameter so causes moderate effect on the differential cross section, and the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, in particular, at small momentum transfer region |t|≤ 0.2 GeV^2.  相似文献   

11.
Soliton density wave is investigated numerically and analytically in the optimal velocity model (a car-following model) of a one-dimensional traffic flow with open boundaries. Soliton density wave is distinguished from the kink density wave. It is shown that the soliton density wave appears only at the threshold of occurrence of traffic jams. The Korteweg-de Vries (KdV) equation is derived from the optimal velocity model by the use of the nonlinear analysis. It is found that the traffic soliton appears only near the neutral stability line. The soliton solution is analytically obtained from the perturbed KdV equation. It is shown that the soliton solution obtained from the nonlinear analysis is consistent with that of the numerical simulation.  相似文献   

12.
We analyze a new car-following model described by a differential-difference equation with a synthesized optimal velocity function (SOVF), which depends on the front interactions between every two adjacent vehicles instead of the weighted average headway. The model is analyzed with the use of the linear stability theory and nonlinear analysis method. The stability and neutral stability condition are obtained. We also derive the modified KdV (Korteweg-de Vries) equation and the kink-antikink soliton solution near the critical point. A simulation is conducted with integrating the differential-difference equation by the Euler scheme. The results of the numerical simulation verify the validity of the new model.  相似文献   

13.
By introducing relative velocities of arbitrary number of cars ahead into the full velocity difference models (FVDM), we present a forward looking relative velocity model (FLRVM) of cooperative driving control system. To our knowledge, the model is an improvement over the similar extension in the forward looking optimal velocity models (FLOVM), because it is more reasonable and realistic in implement of incorporating intelligent transportation system in traffic. Then the stability criterion is investigated by the linear stability analysis with finding that new consideration theoretically lead to the improvement of the stability of traffic flow, and the validity of our theoretical analysis is confirmed by direct simulations. In addition, nonlinear analysis of the model shows that the three waves: triangular shock wave, soliton wave and kink-antikink wave appear respectively in stable, metastable and unstable regions. These correspond to the solutions of the Burgers equation, Korteweg-de Vries (KdV) equation and modified Korteweg-de Vries (mKdV) equation.  相似文献   

14.
Two velocity difference model for a car following theory   总被引:1,自引:0,他引:1  
H.X. Ge  R.J. Cheng 《Physica A》2008,387(21):5239-5245
In the light of the optimal velocity model, a two velocity difference model for a car-following theory is put forward considering navigation in modern traffic. To our knowledge, the model is an improvement over the previous ones theoretically, because it considers more aspects in the car-following process than others. Then we investigate the property of the model using linear and nonlinear analyses. The Korteweg-de Vries equation (for short, the KdV equation) near the neutral stability line and the modified Korteweg-de Vries equation (for short, the mKdV equation) around the critical point are derived by applying the reductive perturbation method. The traffic jam could be thus described by the KdV soliton and the kink-anti-kink soliton for the KdV equation and mKdV equation, respectively. Numerical simulations are made to verify the model, and good results are obtained with the new model.  相似文献   

15.
The car-following model of traffic flow is extended to take into account the relative velocity. The stability condition of this model is obtained by using linear stability theory. It is shown that the stability of uniform traffic flow is improved by considering the relative velocity. From nonlinear analysis, it is shown that three different density waves, that is, the triangular shock wave, soliton wave and kink-antikink wave, appear in the stable, metastable and unstable regions of traffic flow respectively. The three different density waves are described by the nonlinear wave equations: the Burgers equation, Korteweg-de Vries (KdV) equation and modified Korteweg-de Vries (mKdV) equation, respectively.  相似文献   

16.
优化车流的交通流格子模型   总被引:5,自引:0,他引:5       下载免费PDF全文
薛郁 《物理学报》2004,53(1):25-30
在一维交通流格子模型的基础上,分别提出考虑最近邻车和次近邻车以及考虑前、后近邻车相互作用进行车流优化的一维交通流格子模型.应用线性稳定性理论和非线性理论进行分析,得出车流的稳定性条件,并导出了描述交通阻塞相变的mKdV方程.用数值模拟验证了mKdV方程的解,数值模拟结果表明考虑最近邻车和次近邻车的优化车流能够增强车流稳定性,而考虑前、后近邻车的优化车流将使稳定性减小. 关键词: 交通流 交通相变 稳定判据 mKdV方程  相似文献   

17.
Hong-Xia Ge  Rong-Jun Cheng 《Physica A》2008,387(28):6952-6958
The novel lattice hydrodynamic model is presented by incorporating the “backward looking” effect. The stability condition for the the model is obtained using the linear stability theory. The result shows that considering one following site in vehicle motion leads to the stabilization of the system compared with the original lattice hydrodynamic model and the cooperative driving lattice hydrodynamic model. The Korteweg-de Vries (KdV, for short) equation near the neutral stability line is derived by using the reductive perturbation method to show the traffic jam which is proved to be described by KdV soliton solution obtained from the KdV equation. The simulation result is consistent with the nonlinear analysis.  相似文献   

18.
H.X. Ge  R.J. Cheng 《Physica A》2010,389(14):2825-663
The lattice hydrodynamic model is not only a simplified version of the macroscopic hydrodynamic model, but also connected with the microscopic car following model closely. The modified Korteweg-de Vries (mKdV) equation related to the density wave in a congested traffic region has been derived near the critical point since Nagatani first proposed it. But the Korteweg-de Vries (KdV) equation near the neutral stability line has not been studied, which has been investigated in detail for the car following model. We devote ourselves to obtaining the KdV equation from the original lattice hydrodynamic models and the KdV soliton solution to describe the traffic jam. Especially, we obtain the general soliton solution of the KdV equation and the mKdV equation. We review several lattice hydrodynamic models, which were proposed recently. We compare the modified models and carry out some analysis. Numerical simulations are conducted to demonstrate the nonlinear analysis results.  相似文献   

19.
This paper focuses on a two-dimensional bidirectional pedestrian flow model which involves the next-nearest-neighbor effect. The stability condition and the Korteweg-de Vries (KdV) equation are derived to describe the density wave of pedestrian congestion by linear stability and nonlinear analysis. Through theoretical analysis, the soliton solution is obtained.  相似文献   

20.
The higher-order, low-amplitude inertial Alfvén wave (IAW) dressed soliton and chaos are investigated in a magnetized plasma. In the linear limit, the dispersion relation for propagation of IAWs in plasmas is also obtained in the presence of electron thermal effects and illustrated numerically. It is found that the electron inertial length plays an important role for wave dispersion effects and its phase speed is increased on including the electron temperature in the model. The reductive perturbation method is employed to obtain the first-order IAW Korteweg–de Vries (KdV) soliton and second-order dressed soliton solutions analytically, which gives electron density dip (or rarefactive) structure and moves with super Alfvénic speed in plasmas. The numerical illustrations of the KdV and dressed IAW solitons are also presented by using the laboratory and space plasma parameters given in the literature. Furthermore, a numerical study of quasi-periodicity and chaotic behaviour of IAWs in the presence of external periodic force is also discussed in detail. The effects of plasma beta (which depends on plasma density, electron temperature, and magnetic field intensity) and obliqueness of the wave propagation on the formation of nonlinear Alfvénic wave structures have also been presented.  相似文献   

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