平面环行交叉路口交通流的研究

从道路结构出发,对具有内、外环道的平面环形交叉路口建立了具有多个道路瓶颈的元胞自动机模型,对平面环行交叉路口的交通流进行研究.计算机模拟结果表明,环形交叉路口的内环道中与入环车道接壤处是最容易发生阻塞的地方,内环道中车辆之间的非线性相互作用的效应随刹车概率的增大而增强,流量随之减小;而转向概率的增加有助于提高系统交通流量. 关键词： 平面环形交叉路口 元胞自动机模型 瓶颈 自组织     

Specht modules and semisimplicity criteria for Brauer and Birman–Murakami–Wenzl algebras

A construction of bases for cell modules of the Birman–Murakami–Wenzl (or B–M–W) algebra B _n (q,r) by lifting bases for cell modules of B _n−1(q,r) is given. By iterating this procedure, we produce cellular bases for B–M–W algebras on which a large Abelian subalgebra, generated by elements which generalise the Jucys–Murphy elements from the representation theory of the Iwahori–Hecke algebra of the symmetric group, acts triangularly. The triangular action of this Abelian subalgebra is used to provide explicit criteria, in terms of the defining parameters q and r, for B–M–W algebras to be semisimple. The aforementioned constructions provide generalisations, to the algebras under consideration here, of certain results from the Specht module theory of the Iwahori–Hecke algebra of the symmetric group. Research supported by Japan Society for Promotion of Science.     

On logical gates in precipitating medium: Cellular automaton model

We study a two-dimensional semi-totalistic binary cell-state cellular automaton, which imitates a reversible precipitation in an abstract chemical medium. The systems exhibits a non-trivial growth and nucleation. We demonstrate how basic computational operation can be realized in the system when the propagation of the growing patterns is self-restricted by stationary localizations. We show that precipitating patterns of different morphology compete between each other and thus implement basic logical gates.     

A novel algorithm of simulating multi-velocity evacuation based on cellular automata modeling and tenability condition

A cellular automata (CA) model, which adopts the findings of tenability analysis, is proposed to simulate the evacuation from a smoke-filled room. Two algorithms, viz., direct algorithm and indirect algorithm, are used to model the behavior of a crowd consisting of people with different movement velocities. In the indirect algorithm, the movement velocity is related to probability so that the CPU time is greatly reduced. Another novelty is that an experimental formula for estimating the survival duration when exposed to constant concentration of toxic gases in a static environment is extended to one that involves varying degree of toxic gases. This has been incorporated into the CA model.     

A Modified Sensitive Driving Cellular Automaton Model

A modified cellular automaton model for traffic flow on highway is proposed with a novel concept about the variable security gap. The concept is first introduced into the original Nagel-Schreckenberg model, which is called the non-sensitive driving cellular automaton model. And then it is incorporated with a sensitive driving NaSch model, in which the randomization brake is arranged before the deterministic deceleration. A parameter related to the variable security gap is determined through simulation. Comparison of the simulation results indicates that the variable security gap has different influence on the two models. The fundamental diagram obtained by simulation with the modified sensitive driving NaSch model shows that the maximum flow are in good agreement with the observed data, indicating that the presented model is more reasonable and realistic.     

Properties of train traffic flow in moving block system

The development direction of railway is to improve the capacity and the service quality, where the service quality includes safety, schedule, high speed, and comfort. In light of the existing cellular automaton models, in this paper, we develop a model to analyze the mixed running processes of trains with maximal speeds of 500 km/h and 350 km/h respectively in the moving block system. In the proposed model, we establish some sound rules to control the running process of train, where the rules include the departure rules in the intermediate stations, the overtaking rules, and the conditions of speed limitation for train stopping at a station or passing through a station. With the consideration of the mixed ratio and the distance between two adjacent stations, the properties of the train traffic flow (including capacity and average speed) are simulated. The numerical results show that the interactions among different trains will affect the capacity, and a proper increasing of the spatial distance between two adjacent stations can enhance the capacity and the average speed under the moving block.     

2010年上海世博会影响力模型及其综合评价

利用时间序列分析了2010年上海世博会的客流总量,类比二维有热源的热传导问题,建立了世博会带动相关产业发展的热力学传导模型．基于灰色关联分析,得到了定量多因素的评价模型,并据此对上海世博会和前几届世博会做了综合比较．     

Immiscible cellular-automaton fluids

We introduce a new deterministic collision rule for lattice-gas (cellular-automaton) hydrodynamics that yields immiscible two-phase flow. The rule is based on a minimization principle and the conservation of mass, momentum, and particle type. A numerical example demonstrates the spontaneous separation of two phases in two dimensions. Numerical studies show that the surface tension coefficient obeys Laplace's formula.     

Transient and cyclic behavior of cellular automata with null boundary conditions

One-dimensional cellular automata (CA) over finite fields are studied in which each interior cell is updated to contain the sum of the previous values of its two nearest neighbors. Boundary cells are updated according to null boundary conditions. For a given initial configuration, the CA evolves through transient configurations to an attracting cycle. The dependence of the maximal transient length and maximal cycle length on the number of cells is investigated. Both can be determined from the minimal polynomial of the update matrix, which in this case satisfies a useful recurrence relation. With cell values from a field of characteristic two, the explicit dependence of the maximal transient length on the number of cells is determined. Extensions and directions for future work are presented.Deceased.