Corresponding Angle Feedback in an innovative weighted transportation system

The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. In this Letter, we study dynamics of traffic flow with real-time information. The influence of a feedback strategy named Corresponding Angle Feedback Strategy (CAFS) is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.     

房间出口位置及内部布局对疏散效率的影响研究

利用先前建立的元胞自动机人员疏散模型,考虑教室类房间内过道区域的影响因素,调整行人转移概率的计算规则,分析了教室不同出口位置、教室内不同布局情况下的疏散效率.结果表明,正对教室过道的出口对疏散是很有利的,教室正面边缘开口和侧面开口相比,宜在侧面开口,以减少行人运动过程中方向的变化,而教室正面中央开口虽然疏散效率最高,但这样的开口不现实;另外,当教室侧面开口时,紧靠出口墙壁侧的过道是必要的,当教室总容量不变时,应优先考虑过道分布的设计,过道的数目和单个过道宽度相比,过道数目对疏散效率的影响更显著,过道数量较多时,疏散效率较高.本文有望为教室内部布局和出口设置,以及影剧院、体育馆看台等类似建筑内座椅和过道的分布设计提供建议.     

基于改进元胞自动机的数字保密通信方案

为了提高现有混沌保密通信系统的加解密速度和安全性,提出了一种新的即时同步流密码数字保密通信方案,在该方案中利用改进元胞自动机进行加密,并采用扩展密钥技术和置乱技术.数值模拟结果表明:该方案能产生随机性很好的流密码,并且具有较高的加解密速度和非常高的抗破译能力.     

三维自助式类渗流细胞自动机的临界值

本文研究三维自助式类渗流细胞自动机的临界值．得出临界值pc＝0的一些充分条件和必要条件．当pc＞0时，利用定向点渗流的临界值，给出了pc上、下界的显式估计．     

Diffusion in Lorentz lattice gas cellular automata: The honeycomb and quasi-lattices compared with the square and triangular lattices

We study numerically the nature of the diffusion process on a honeycomb and a quasi-lattice, where a point particle, moving along the bonds of the lattice, scatters from randomly placed scatterers on the lattice sites according to strictly deterministic rules. For the honeycomb lattice fully occupied by fixed rotators two (symmetric) isolated critical points appear to be present, with the same hyperscaling relation as for the square and the triangular lattices. No such points appear to exist for the quasi-lattice. A comprehensive comparison is made with the behavior on the previously studied square and triangular lattices. A great variety of diffusive behavior is found, ranging from propagation, superdiffusion, normal, quasi-normal, and anomalous, to absence of diffusion. The influence of the scattering rules as well as of the lattice structure on the diffusive behavior of a point particle moving on the all lattices studied so far is summarized.     

Lattice games without rational strategies

We show that the lattice games of Guo and Miller support universal computation, disproving their conjecture that all lattice games have rational strategies. We also state an explicit counterexample to that conjecture: a three dimensional lattice game whose set of winning positions does not have a rational generating function.     

Simulating synchronized traffic flow and wide moving jam based on the brake light rule

A new cellular automaton (CA) model based on brake light rules is proposed, which considers the influence of deterministic deceleration on randomization probability and deceleration extent. To describe the synchronized flow phase of Kerner’s three-phase theory in accordance with empirical data, we have changed some rules of vehicle motion with the aim to improve speed and acceleration vehicle behavior in synchronized flow simulated with earlier cellular automaton models with brake lights. The fundamental diagrams and spatial–temporal diagrams are analyzed, as well as the complexity of the traffic evolution, the emergence process of wide moving jam. Simulation results show that our new model can reproduce the three traffic phases: free flow, synchronized flow and wide moving jam. In addition, our new model can well describe the complexity of traffic evolution: (1) with initial homogeneous distribution and large densities, the traffic will evolve into multiple steady states, in which the numbers of wide moving jams are not invariable. (2) With initial homogeneous distribution and the middle range of density, the wide moving jam will emerge stochastically. (3) With initial mega-jam distribution and the density close to a point with the low value, the initial mega-jam will disappear stochastically. (4) For the cases with multiple wide moving jams, the process is analyzed involving the generation of narrow moving jam due to “pinch effect”, which leads to wide moving jam emergence.     

Negative-viscosity lattice gases

A new irreversible collision rule is introduced for lattice-gas automata. The rule maximizes the flux of momentum in the direction of the local momentum gradient, yielding a negative shear viscosity. Numerical results in 2D show that the negative viscosity leads to the spontaneous ordering of the velocity field, with vorticity resolvable down to one lattice-link length. The new rule may be used in conjunction with previously proposed collision rules to yield a positive shear viscosity lower than the previous rules provide. In particular, Poiseuille flow tests demonstrate a decrease in viscosity by more than a factor of 2.     

高速公路封道施工路段交通流特性及通行能力分析——以杭州湾大桥内侧两条车道封道情形为例

基于交通流实测数据,针对三车道高速公路杭州湾大桥路段内侧两条车道因施工而封闭时的情形,建立元胞自动机交通流模型.根据公路养护安全作业规程和车辆行驶特点,细致划分了施工路段各区域,采用不同的换道规则来模拟不同区域中车辆的换道行为,区分车型和司机性格差异,模拟结果与实测数据吻合良好,验证了模型的有效性.通过数值模拟,研究发现封道时流量和速度随着进车率增加均有不同程度的下降,并且流量还会因施工区域长度的增加而下降.此外,通过分析封道时的道路服务水平评价指标与交通流特征值之间的关系,得出在三级服务水平以上时,道路通行能力能得到基本的保证,以此推荐了极限流量值,可为高速公路封道时的交通管理提供理论依据.