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Showing papers in "Chinese Physics B in 2009"


Journal ArticleDOI
TL;DR: In this article, the authors studied the behavior of runaway electrons in the flat-top phase of electron cyclotron resonance heating discharges in the HL-2A Tokamak and found that both hard x-ray radiation intensity and neutron emission flux fall rapidly to a very low level.
Abstract: During the current flat-top phase of electron cyclotron resonance heating discharges in the HL-2A Tokamak, the behaviour of runaway electrons has been studied by means of hard x-ray detectors and neutron diagnostics. During electron cyclotron resonance heating, it can be found that both hard x-ray radiation intensity and neutron emission flux fall rapidly to a very low level, which suggests that runaway electrons have been suppressed by electron cyclotron resonance heating. From the set of discharges studied in the present experiments, it has also been observed that the efficiency of runaway suppression by electron cyclotron resonance heating was apparently affected by two factors: electron cyclotron resonance heating power and duration. These results have been analysed by using a test particle model. The decrease of the toroidal electric field due to electron cyclotron resonance heating results in a rapid fall in the runaway electron energy that may lead to a suppression of runaway electrons. During electron cyclotron resonance heating with different powers and durations, the runaway electrons will experience different slowing down processes. These different decay processes are the major cause for influencing the efficiency of runaway suppression. This result is related to the safe operation of the Tokamak and may bring an effective control of runaway electrons.

255 citations


Journal ArticleDOI
TL;DR: In this article, a car-following model by taking into account the effects of the traffic interruption probability on the following vehicle is presented, and the stability condition of the model is obtained by using the linear stability theory.
Abstract: In this paper, we present a new car-following model by taking into account the effects of the traffic interruption probability on the car-following behaviour of the following vehicle. The stability condition of the model is obtained by using the linear stability theory. The modified Korteweg–de Vries (KdV) equation is constructed and solved, and three types of traffic flows in the headway sensitivity space–stable, metastable, and unstable–are classified. Both the analytical and simulation results show that the traffic interruption probability indeed has an influence on driving behaviour, and the consideration of traffic interruption probability in the car-following model could stabilize traffic flow.

99 citations


Journal ArticleDOI
TL;DR: The improved boundary element-free method (IBEFM) as discussed by the authors is a meshless boundary integral equation method based on the IMLS method, in which the basic unknown quantity is the real solution of the nodal variables.
Abstract: The interpolating moving least-squares (IMLS) method is discussed first in this paper. And the formulae of the IMLS method obtained by Lancaster are revised. Then on the basis of the boundary element-free method (BEFM), combining the boundary integral equation (BIE) method with the IMLS method, the improved boundary element-free method (IBEFM) for two-dimensional potential problems is presented, and the corresponding formulae of the IBEFM are obtained. In the BEFM, boundary conditions are applied directly, but the shape function in the MLS does not satisfy the property of the Kronecker δ function. This is a problem of the BEFM, and must be solved theoretically. In the IMLS method, when the shape function satisfies the property of the Kronecker δ function, then the boundary conditions, in the meshless method based on the IMLS method, can be applied directly. Then the IBEFM, based on the IMLS method, is a direct meshless boundary integral equation method in which the basic unknown quantity is the real solution of the nodal variables, and the boundary conditions can be applied directly and easily, thus it gives a greater computational precision. Some numerical examples are presented to demonstrate the method.

80 citations


Journal ArticleDOI
TL;DR: In this paper, a double N layer was used to substitute the single microcrystalline silicon n layer in n/p tunnel recombination junction between subcells in a-Si:H/μc-Si-H tandem solar cells.
Abstract: This paper reports that a double N layer (a-Si:H/μc-Si:H) is used to substitute the single microcrystalline silicon n layer (n-μc-Si:H) in n/p tunnel recombination junction between subcells in a-Si:H/μc-Si:H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current–voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si:H/μc-Si:H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.

80 citations


Journal ArticleDOI
TL;DR: By modifying the distribution process of particles and adding a detection step after each distribution process, this work proposes an improved protocol which can resist this kind of attack.
Abstract: The security of quantum secret sharing based on entanglement swapping is revisited and a participant attack is presented. In this attack two dishonest agents together can illegally recover the secret quantum state without the help of any other controller, and it will not be detected by any other users. Furthermore, by modifying the distribution process of particles and adding a detection step after each distribution process, we propose an improved protocol which can resist this kind of attack.

60 citations


Journal ArticleDOI
TL;DR: The concept of fine-grained PE (FGPE) is proposed, defined by the order pattern and magnitude of the difference between neighbouring values, and consequently FGPE becomes more sensitive to the dynamical change of time series than does PE.
Abstract: In a recent paper [2002 Phys. Rev. Lett. 88 174102], Bandt and Pompe propose permutation entropy (PE) as a natural complexity measure for arbitrary time series which may be stationary or nonstationary, deterministic or stochastic. Their method is based on a comparison of neighbouring values. This paper further develops PE, and proposes the concept of fine-grained PE (FGPE) defined by the order pattern and magnitude of the difference between neighbouring values. This measure excludes the case where vectors with a distinct appearance are mistakenly mapped onto the same permutation type, and consequently FGPE becomes more sensitive to the dynamical change of time series than does PE, according to our simulation and experimental results.

55 citations


Journal ArticleDOI
TL;DR: Security analysis shows the present scheme is secure against intercept-resend attack and the impersonator's attack, and it is more economic with present-day techniques and easily processed by a one-way quantum computer.
Abstract: A novel efficient deterministic secure quantum communication scheme based on four-qubit cluster states and single-photon identity authentication is proposed. In this scheme, the two authenticated users can transmit two bits of classical information per cluster state, and its efficiency of the quantum communication is 1/3, which is approximately 1.67 times that of the previous protocol presented by Wang et al [Chin. Phys. Lett. 23 (2006) 2658]. Security analysis shows the present scheme is secure against intercept-resend attack and the impersonator's attack. Furthermore, it is more economic with present-day techniques and easily processed by a one-way quantum computer.

49 citations


Journal ArticleDOI
于宙, 李祥, 龙雪, 程兴旺, 刘颖, 曹传宝 
TL;DR: In this article, a chemical method is employed to synthesize Co and Al co-doped ZnO, namely, Zn0.99-xCo0.01AlxO dilution semiconductors with the nominal composition of x = 0, 0.005 and 0.02.
Abstract: This paper reports that a chemical method is employed to synthesize Co and Al co-doped ZnO, namely, Zn0.99-xCo0.01AlxO dilution semiconductors with the nominal composition of x = 0, 0.005 and 0.02. Structural, magnetic and optical properties of the produced samples are studied. The results indicate that samples sintered in air under the temperatures of 500 °C show a single wurtzite ZnO structure and the ferromagnetism decreases with the increase of Al. Photoluminescence spectra of different Al-doped samples indicate that increasing Al concentration in Zn0.99-xCo0.01AlxO results in a decrease of Zni, which resembles the trend of the ferromagnetic property of the corresponding samples. Therefore, it is deduced that the ferromagnetism observed in the studied samples originates from the interstitial defect of zinc (Zni) in the lattice of Co-doped ZnO.

49 citations


Journal ArticleDOI
TL;DR: This paper presents a quantum key distribution protocol to distribute secure key bits among one quantum party and numerous classical parties who have no quantum capacity and proves that this protocol is completely robust, i.e., any eavesdropping attack should be detected with nonzero probability.
Abstract: Secure key distribution among classical parties is impossible both between two parties and in a network. In this paper, we present a quantum key distribution (QKD) protocol to distribute secure key bits among one quantum party and numerous classical parties who have no quantum capacity. We prove that our protocol is completely robust, i.e., any eavesdropping attack should be detected with nonzero probability. Our calculations show that our protocol may be secure against Eve's symmetrically individual attack.

46 citations


Journal ArticleDOI
TL;DR: In this article, a solid-state reaction was performed on Ca2Si5N8:Eu2+ phosphor to synthesize Ca1.9Eu0.
Abstract: We have synthesized Ca2Si5N8:Eu2+ phosphor through a solid-state reaction and investigated its structural and luminescent properties. Our Rietveld refinement of the crystal structure of Ca1.9Eu0.1Si5N8 reveals that Eu atoms substituting for Ca atoms occupy two crystallographic positions. Between 10 K and 300 K, Ca2Si5N8:Eu2+ phosphor shows a broad red emission band centred at ~1.97 eV–2.01 eV. The gravity centre of the excitation band is located at 3.0 eV–3.31 eV. The centroid shift of the 5d levels of Eu2+ is determined to be ~1.17 eV, and the red-shift of the lowest absorption band to be ~0.54 eV due to the crystal field splitting. We have analysed the temperature dependence of PL by using a configuration coordinate model. The Huang–Rhys parameter S = 6.0, the phonon energy hv = 52 meV, and the Stokes shift ΔS = 0.57 eV are obtained. The emission intensity maximum occurring at ~200 K can be explained by a trapping effect. Both photoluminescence (PL) emission intensity and decay time decrease with temperature increasing beyond 200 K due to the non-radiative process.

44 citations


Journal ArticleDOI
TL;DR: An interesting result is that a lower cost is achieved by using the control scheme of pinning nodes with smaller degrees in the synchronization of different star-shaped networks.
Abstract: The problem of pinning control for the synchronization of complex dynamical networks is discussed in this paper. A cost function of the controlled network is defined by the feedback gain and the coupling strength of the network. An interesting result is that a lower cost is achieved by using the control scheme of pinning nodes with smaller degrees. Some strict mathematical analyses are presented for achieving a lower cost in the synchronization of different star-shaped networks. Numerical simulations on some non-regular complex networks generated by the Barabasi–Albert model and various star-shaped networks are performed for verification and illustration.

Journal ArticleDOI
TL;DR: In this paper, the magnetic properties and magnetocaloric effects of La1−xRxFe11.5Si1.5 (R = Pr, (0 ≤ x ≤ 0.5); R = Ce, Pr and Nd) compounds are investigated, and the substitution of R for La causes an enhancement in field-induced itinerant electron metamagnetic transition, which leads to a remarkable increase in magnetic entropy change ΔSm and also in hysteresis loss.
Abstract: Magnetic properties and magnetocaloric effects of La1−xRxFe11.5Si1.5 (R = Pr, (0 ≤ x ≤ 0.5); R = Ce and Nd, (0 ≤ x ≤ 0.3)) compounds are investigated. Partially replacing La with R = Ce, Pr and Nd in La1−xRxFe11.5Si1.5 leads to a reduction in Curie temperature due to the lattice contraction. The substitution of R for La causes an enhancement in field-induced itinerant electron metamagnetic transition, which leads to a remarkable increase in magnetic entropy change ΔSm and also in hysteresis loss. However, a high effective refrigerant capacity RCeff is still maintained in La1−xRxFe11.5Si1.5. In the present samples, a large ΔSm and a high RCeff have been achieved simultaneously.

Journal ArticleDOI
TL;DR: A neighbour-based coordination scheme is proposed for a multi-agent system with multiple leaders and the results show that all the agents will flock to the polytope region formed by the leaders.
Abstract: A neighbour-based coordination scheme is proposed for a multi-agent system with multiple leaders. Under assumptions of the connectivity of the interconnection topology and a simple first-order dynamics model for each mobile agent, the results show that all the agents will flock to the polytope region formed by the leaders.

Journal ArticleDOI
TL;DR: In this paper, a novel helix-like ZnO nanostructure with several tens of nanometres in thickness was synthesized on a gold-coated Si substrate by thermal evaporation of zinc sulfide powder at 1020°C.
Abstract: This paper reports a novel helix-like ZnO nanostructure with several tens of nanometres in thickness synthesized on a gold-coated Si substrate by thermal evaporation of zinc sulfide powder at 1020°C. Transmission electron microscope characterization shows that as-synthesized ZnO nanohelices extend along [011] direction and the axial direction of the helix is along [0001] direction. A catalyst-intervened dislocation-induced growth mechanism has been suggested to explain the formation of the helix-like ZnO nanostructures. This study opens a new route to construct helix-like ZnO nanostructures by different evaporation sources.

Journal ArticleDOI
TL;DR: In this article, Wang et al. presented a new function expansion method for finding travelling wave solutions of a nonlinear evolution equation and called it the (ω/g)-expansion method, which can be thought of as the generalization of (G'/G)/G-expansion given by Wang this article.
Abstract: This paper presents a new function expansion method for finding travelling wave solutions of a nonlinear evolution equation and calls it the (ω/g)-expansion method, which can be thought of as the generalization of (G'/G)-expansion given by Wang et al recently. As an application of this new method, we study the well-known Vakhnenko equation which describes the propagation of high-frequency waves in a relaxing medium. With two new expansions, general types of soliton solutions and periodic solutions for Vakhnenko equation are obtained.

Journal ArticleDOI
TL;DR: In this paper, the collective excitation and stability of low-dimensional Bose-Einstein condensates with two-and three-body interactions were investigated by variational analysis of the time-dependent Gross-Pitaevskii-Ginzburg equation.
Abstract: This paper investigates the collective excitation and stability of low-dimensional Bose–Einstein condensates with two- and three-body interactions by the variational analysis of the time-dependent Gross–Pitaevskii–Ginzburg equation. The spectrum of the low-energy excitation and the effective potential for the width of the condensate are obtained. The results show that: (i) the repulsive two-body interaction among atoms makes the frequency red-shifted for the internal excitation and the repulsive or attractive three-body interaction always makes it blue-shifted; (ii) the region for the existence of the stable bound states is obtained by identifying the critical value of the two- and three-body interactions.

Journal ArticleDOI
TL;DR: Circuit experiment simulation results verify the effectiveness of the proposed circuit unit, designed to realize a 3.8-order generalized Lorenz chaotic system and synchronization between two fractional-order systems by utilizing a single-variable feedback method.
Abstract: The chaotic behaviours of a fractional-order generalized Lorenz system and its synchronization are studied in this paper. A new electronic circuit unit to realize fractional-order operator is proposed. According to the circuit unit, an electronic circuit is designed to realize a 3.8-order generalized Lorenz chaotic system. Furthermore, synchronization between two fractional-order systems is achieved by utilizing a single-variable feedback method. Circuit experiment simulation results verify the effectiveness of the proposed scheme.

Journal ArticleDOI
TL;DR: In this article, the time evolution of the quantum mechanical state of an electron by using variational method of Pekar type on the condition of electric-LO-phonon strong coupling in a parabolic quantum dot was calculated.
Abstract: This paper calculates the time evolution of the quantum mechanical state of an electron by using variational method of Pekar type on the condition of electric–LO-phonon strong coupling in a parabolic quantum dot. It obtains the eigenenergies of the ground state and the first-excited state, the eigenfunctions of the ground state and the first-excited state This system in a quantum dot may be employed as a two-level quantum system qubit. The superposition state electron density oscillates in the quantum dot with a period when the electron is in the superposition state of the ground and the first-excited state. It studies the influence of the electric field on the eigenenergies of the ground state, the first-excited state and the period of oscillation at the different electron–LO-phonon coupling constant and the different confinement length.

Journal ArticleDOI
TL;DR: A nonlinear controller, which is simple and easy to be constructed, is presented to achieve finite-time chaos control based on the finite- time stability theory and results show that the proposed controller is very effective.
Abstract: This paper reports that the performance of permanent magnet synchronous motor (PMSM) degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in PMSM, a nonlinear controller, which is simple and easy to be constructed, is presented to achieve finite-time chaos control based on the finite-time stability theory. Computer simulation results show that the proposed controller is very effective. The obtained results may help to maintain the industrial servo driven system's security operation.

Journal ArticleDOI
TL;DR: In this article, the periodic power variation of the pulse-train in a passively mode-locked soliton fiber ring laser was investigated and it was shown that the non-uniformity is caused by the interaction between the nonuniform polarization states of the soliton pulses and the passive polarizer in the cavity.
Abstract: This paper reports the periodic power variation of the pulse-train in a passively mode-locked soliton fiber ring laser. It can obtain either the uniform or nonuniform pulse-train output by simply rotating the polarization controllers. The experimental results show that the pulse-train nonuniformity is caused by the interaction between the nonuniform polarization states of the soliton pulses and the passive polarizer in the cavity.

Journal ArticleDOI
冉政1
TL;DR: In this paper, the Galilean invariance and the induced thermo-hydrodynamics of the lattice Boltzmann Bhatnagar-Gross-Krook model are proposed together with their rigorous theoretical background.
Abstract: The Galilean invariance and the induced thermo-hydrodynamics of the lattice Boltzmann Bhatnagar–Gross–Krook model are proposed together with their rigorous theoretical background. From the viewpoint of group invariance, recovering the Galilean invariance for the isothermal lattice Boltzmann Bhatnagar–Gross–Krook equation (LBGKE) induces a new natural thermal-dynamical system, which is compatible with the elementary statistical thermodynamics.

Journal ArticleDOI
TL;DR: In this article, the authors studied the propagation properties of Gauss-Bessel beams in a turbulent atmosphere and derived the intensity distribution expression for such beams propagating in turbulent atmosphere, then the influence of turbulence and source beam parameters on the beam propagation was studied in great detail.
Abstract: This paper studies the propagation properties of Gauss–Bessel beams in a turbulent atmosphere. Based on the extended Huygens–Fresnel principle, it derives the intensity distribution expression for such beams propagating in a turbulent atmosphere. Then the influence of turbulence and source beam parameters on the beam propagation is studied in great detail. It finds that the intensity distribution of Gauss–Bessel beams will change into Gaussian profile in a turbulent atmosphere, and that stronger turbulence and smaller topological charges will lead to a faster changing.

Journal ArticleDOI
TL;DR: A modified digital chaotic sequence generator based on chaotic logistic systems with a coupling structure where one chaotic subsystem generates perturbation signals to disturb the control parameter of the other one to improve the dynamical degradation of digital chaos.
Abstract: Chaotic systems perform well as a new rich source of cryptography and pseudo-random coding. Unfortunately their digital dynamical properties would degrade due to the finite computing precision. Proposed in this paper is a modified digital chaotic sequence generator based on chaotic logistic systems with a coupling structure where one chaotic subsystem generates perturbation signals to disturb the control parameter of the other one. The numerical simulations show that the length of chaotic orbits, the output distribution of chaotic system, and the security of chaotic sequences have been greatly improved. Moreover the chaotic sequence period can be extended at least by one order of magnitude longer than that of the uncoupled logistic system and the difficulty in decrypting increases 2128*2128 times indicating that the dynamical degradation of digital chaos is effectively improved. A field programmable gate array (FPGA) implementation of an algorithm is given and the corresponding experiment shows that the output speed of the generated chaotic sequences can reach 571.4 Mbps indicating that the designed generator can be applied to the real-time video image encryption.

Journal ArticleDOI
TL;DR: A modified sol-gel method is used for synthesizing Nd ion doped lead zirconate titanate nanopowders Pb1-3x/2NdxZr0.52Ti0.48O3 as mentioned in this paper.
Abstract: A modified sol-gel method is used for synthesizing Nd ion doped lead zirconate titanate nanopowders Pb1–3x/2NdxZr0.52Ti0.48O3 (PNZT) in an ethylene glycol system with zirconium nitrate as zirconium source. The results show that it is critical to add lead acetate after the reaction of zirconium nitrate with tetrabutyl titanate in the ethylene glycol system for preparing PNZT with an exact fraction of titanium content. It has been observed that the dopant of excess Nd ions can effectively improve the sintered densification and activity of the PNZT ceramics. Piezoelectric, dielectric and ferroelectric properties of the PNZT ceramics are remarkably enhanced as compared with those of monolithic lead zirconate titanate (PZT). Especially, the supreme values of piezoelectric constant (d33) and dielectric constant () for the PNZT are both about two times that of the monolithic PZT and moreover, the remnant polarization (Pr) also increases by 30%. According to the analysis of the structures and properties, we attribute the improvement in electrical properties to the lead vacancies caused by the doping of Nd ions.

Journal ArticleDOI
TL;DR: The existence of a min-weighted rigid graph is proved by using the rigidity matrix, and three algorithms for generating min- Weighted rigid and min- weighted persistent graphs are presented.
Abstract: This paper researched into some methods for generating min-weighted rigid graphs and min-weighted persistent graphs. Rigidity and persistence are currently used in various studies on coordination and control of autonomous multi-agent formations. To minimize the communication complexity of formations and reduce energy consumption, this paper introduces the rigidity matrix and presents three algorithms for generating min-weighted rigid and min-weighted persistent graphs. First, the existence of a min-weighted rigid graph is proved by using the rigidity matrix, and algorithm 1 is presented to generate the min-weighted rigid graphs. Second, the algorithm 2 based on the rigidity matrix is presented to direct the edges of min-weighted rigid graphs to generate min-weighted persistent graphs. Third, the formations with range constraints are considered, and algorithm 3 is presented to find whether a framework can form a min-weighted persistent formation. Finally, some simulations are given to show the efficiency of our research.

Journal ArticleDOI
TL;DR: Nonlinear consensus protocols for dynamic directed networks of multi-agent systems with flxed and switching topologies are investigated separately and are shown to be more efiective than the linear protocols for the formation control of the agents and they are an improvement over existing protocols.
Abstract: Nonlinear consensus protocols for dynamic directed networks of multi-agent systems with flxed and switching topologies are investigated separately in this paper. Based on the centre manifold reduction technique, nonlinear consensus protocols are presented. We prove that a group of agents can reach a fl-consensus, the value of which is the group decision value varying from the minimum and the maximum values of the initial states of the agents. Moreover, we derive the conditions to guarantee that all the agents reach a fl{consensus on a desired group decision value. Finally, a simulation study concerning the vertical alignment manoeuvere of a team of unmanned air vehicles is performed. Simulation results show that the nonlinear consensus protocols proposed are more efiective than the linear protocols for the formation control of the agents and they are an improvement over existing protocols.

Journal ArticleDOI
TL;DR: In this paper, a scheme for high-capacity three-party quantum secret sharing with quantum superdense coding is presented, where the two agents Bob and Charlie encode their information with dense coding unitary operations, and security is checked by inserting decoy photons.
Abstract: This paper presents a scheme for high-capacity three-party quantum secret sharing with quantum superdense coding, following some ideas in the work by Liu et al (2002 Phys. Rev. A 65 022304) and the quantum secret sharing scheme by Deng et al (2008 Phys. Lett. A 372 1957). Instead of using two sets of nonorthogonal states, the boss Alice needs only to prepare a sequence of Einstein–Podolsky–Rosen pairs in d-dimension. The two agents Bob and Charlie encode their information with dense coding unitary operations, and security is checked by inserting decoy photons. The scheme has a high capacity and intrinsic efficiency as each pair can carry 2lbd bits of information, and almost all the pairs can be used for carrying useful information.

Journal ArticleDOI
TL;DR: In this paper, the theoretical tensile strength of bcc and fcc Fe has been investigated using a first-principles total energy method, and the results provide a good reference to understand the intrinsic mechanical properties of Fe as a potential structural material in the nuclear fusion Tokamak.
Abstract: This paper employs a first-principles total-energy method to investigate the theoretical tensile strengths of bcc and fcc Fe systemically. It indicates that the theoretical tensile strengths are shown to be 12.4, 32.7, 27.5 GPa for bcc Fe, and 48.1, 34.6, 51.2 GPa for fcc Fe in the [001], [110] and [111] directions, respectively. For bcc Fe, the [001] direction is shown to be the weakest direction due to the occurrence of a phase transition from ferromagnetic bcc Fe to high spin ferromagnetic fcc Fe. For fcc Fe, the [110] direction is the weakest direction due to the formation of an instable saddle-point 'bct structure' in the tensile process. Furthermore, it demonstrates that a magnetic instability will occur under a tensile strain of 14%, characterized by the transition of ferromagnetic bcc Fe to paramagnetic fcc Fe. The results provide a good reference to understand the intrinsic mechanical properties of Fe as a potential structural material in the nuclear fusion Tokamak.

Journal ArticleDOI
TL;DR: In this article, an improved multiple car-following (MCF) model is proposed by taking into account multiple information inputs from preceding vehicles, and linear stability condition of the model is obtained by using the linear stability theory.
Abstract: On the basis of the full velocity difference (FVD) model, an improved multiple car-following (MCF) model is proposed by taking into account multiple information inputs from preceding vehicles. The linear stability condition of the model is obtained by using the linear stability theory. Through nonlinear analysis, a modified Korteweg-de Vries equation is constructed and solved. The traffic jam can thus be described by the kink–antikink soliton solution for the mKdV equation. The improvement of this new model over the previous ones lies in the fact that it not only theoretically retains many strong points of the previous ones, but also performs more realistically than others in the dynamical evolution of congestion. Furthermore, numerical simulation of traffic dynamics shows that the proposed model can avoid the disadvantage of negative velocity that occurs at small sensitivity coefficients λ in the FVD model by adjusting the information on the multiple leading vehicles. No collision occurs and no unrealistic deceleration appears in the improved model.

Journal ArticleDOI
Zhu Hui-bing1
TL;DR: In this paper, the authors proposed two lattice traffic models by taking into account the drivers' delay in response, and the stability conditions for the two models were obtained by using the linear stability theory.
Abstract: This paper proposes two lattice traffic models by taking into account the drivers' delay in response. The lattice versions of the hydrodynamic model are described by the differential-difference equation and difference-difference equation, respectively. The stability conditions for the two models are obtained by using the linear stability theory. The modified KdV equation near the critical point is derived to describe the traffic jam by using the reductive perturbation method, and the kink–antikink soliton solutions related to the traffic density waves are obtained. The results show that the drivers' delay in sensing headway plays an important role in jamming transition.