检索结果-南通市图书馆

Science china(Technological Sciences) 2010年第12期53卷 3264-3274页

作者： xu meng1 & gao ziyou2 1 moe key laboratory for urban transportation complex systems theory and technology, beijing jiaotong university, beijing 100044, china 2 Institute of systems Science, School of Traffic and transportation, beijing jiaotong university, beijing 100044, china moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Beijing China Institute of systems Science School of Traffic and Transportation Beijing Jiaotong University Beijing China

This paper is concerned with the algorithm of the supply chain network equilibrium model and its equivalent supernetwork based traffic network equilibrium model with elastic demands. Both models are further written as nonlinear complementarity problems. Semismooth least squares reformulations of the complementarity problems are presented and their convergence properties are investigated. Considering the drawbacks of Quasi-Newton method (using the Fischer-Burmeister function), a semi-smooth Levenberg-Marquardt-type method is proposed to solve the problems. Numerical examples show that the Levenberg-Marquardt-type method can solve the supply chain network equilibrium model and its equivalent supernetwork based traffic network equilibrium model significantly, and is more efficient than the Quasi Newton method and the modified projection method. Furthermore, the Levenberg-Marquardt-type method with the equivalent supernetwork based complementarity formulation can be implemented faster than with the supply chain network equilibrium complementarity formulation.

关键词： supply chain networks traffic network equilibrium supernetwork nonlinear complementarity problem Levenberg Marquardt-type method

A complementary formulation for traffic equilibrium problem with a new nonadditive route cost

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Science china(Technological Sciences) 2011年第9期54卷 2525-2530页

作者： xu meng gao ziyou moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Beijing 100044 China Institute of systems Science School of Traffic and Transportation Beijing Jiaotong University Beijing 100044 China

Improviag transportation system is essential for all people in each city since transport plays a very important role. Using mathematical programming approach transport problem is an effective way to improve transportation system. In this paper, the traffic equilibrium problem （TEP） with a general nonadditive route cost function is studied. We formulate the route cost function for each route as a disutility function, which can evaluate route cost function flexibly and analyze the route toll conveniently. Furthermore, we present the TEP with a nonlinear complementary problem （NCP） formulation. The monotonicity and the existence with the NCP formulation are also given under relative assumptions.

关键词： traffic equilibrium problem nonadditive cost nonlinear complementarity problem

Topological-based bottleneck analysis and improvement strategies for traffic networks

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Science china(Technological Sciences) 2009年第10期52卷 2814-2822页

作者： JianJun Wu ziyou gao HuiJun Sun State key laboratory of Rail Traffic Control and Safety (beijing jiaotong university) Beijing 100044 China School of Traffic and transportation Beijing Jiaotong University Beijing 100044 China moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Beijing 100044 China

A method is proposed to find key components of traffic networks with homogenous and heterogeneous topologies, in which heavier traffic flow is transported. One component, called the skeleton, is the minimum spanning tree (MST) based on the zero flow cost (ZCMST). The other component is the infinite incipient percolation cluster (IIC) which represents the spine of the traffic network. Then, a new method to analysis the property of the bottleneck in a large scale traffic network is given from a macroscopic and statistical viewpoint. Moreover, three effective strategies are proposed to alleviate traffic congestion. The significance of the findings is that one can significantly improve the global transport by enhancing the capacity in the ZCMST with a few links, while for improving the local traffic property, improving a tiny fraction of the traffic network in the IIC is effective. The result can be used to help traffic managers prevent and alleviate traffic congestion in time, guard against the formation of congestion bottleneck, and make appropriate policies for traffic demand management. Meanwhile, the method has very important theoretical significance and practical worthiness in optimizing traffic organization, traffic control, and disposal of emergency.

关键词： traffic congestion user equilibrium assignment heterogeneous and homogenous networks

Car capacity near bus stops with mixed traffic derived by additive-conflict-flows procedure

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Science china(Technological Sciences) 2011年第3期54卷 733-740页

作者： YANG XiaoBao gao ziyou SI BingFeng gao Liang moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Beijing 100044 China

To determinate car capacity at bus stops with mixed traffic, a new theoretical approach was developed on the basis of additive-conflict-flows procedure. The procedure was extended from homogeneous traffic flow to mixed traffic flow. The conflicts among cars, buses and bicycles near the stop can be described by the extended procedure. The procedure can be understood more easily than the theory of gap acceptance. Car capacity near the stop is the function of both bus stream and bicycle stream. The proposed model can also analyze the cases of pedestrian effects and limited priority of bicyclists. Numerical results show that the car capacity decreases with the increasing flow rates of other streams. In addition, pedestrian effects and bicyclist's limited priority have negative effects on car capacity near bus stops with mixed traffic flow.

关键词： road capacity bus stop additive-conflict-flows procedure mixed traffic flow

urban TRANSIT ASSIGNMENT MODEL BASED ON AUGMENTED NETWORK WITH IN-VEHICLE CONGESTION AND TRANSFER CONGESTION

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Journal of systems Science and systems Engineering 2011年第2期20卷 155-172页

作者： Bingfeng SI Ming ZHONG Xiaobao YANG ziyou gao moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Beijing 100044 China Department of Civil Engineering University of New Brunswick Fredericton New Brunswick E3B 5A3 Canada

This paper presents an augmented network model to represent urban transit *** such network model,the urban transit assignment problem can be easily modeled like a generalized traffic ***,the feasible route in such augmented transit network is then defined in accordance with the passengers＇ *** passengers＇ travel costs including walking time,waiting time,in-vehicle time and transfer time are formulated while the congestions at stations and the congestions in transit vehicles are all taken into *** the base of these,an equilibrium model for urban transit assignment problem is presented and an improved shortest path method based algorithm is also proposed to solve ***,a numerical example is provided to illustrate our approach.

关键词： Transit assignment augmented network congestion transfer algorithm

MODELING THE CONGESTION COST AND VEHICLE EMISSION WITHIN MULTIMODAL TRAFFIC NETWORK UNDER THE CONDITION OF EQUILIBRIUM

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Journal of systems Science and systems Engineering 2012年第4期21卷 385-402页

作者： Bingfeng SI Ming ZHONG Xiaobao YANG ziyou gao moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong University Department of Civil Engineering University of New BrunswickFrederictonN.B.Canada

Traditional system optimization models for traffic network focus on the treatment of congestion, which usually have an objective of minimizing the total travel time. However, the negative externality of congestion, such as environment pollution, is neglected in most cases. Such models fall short in taking Greenhouse Gas （GHG） emissions and its impact on climate change into consideration. In this paper, a social-cost based system optimization （SO） model is proposed for the multimodal traffic network considering both traffic congestion and corresponding vehicle emission. Firstly, a variation inequality model is developed to formulate the equilibrium problem for such network based on the analysis of travelers＇ combined choices. Secondly, the computational models of traffic congestion and vehicle emission of whole multimodal network are proposed based on the equilibrium link-flows and the corresponding travel times. A bi-level programming model, in which the social-cost based SO model is treated as the upper-level problem and the combined equilibrium model is processed as the lower-level problem, is then presented with its solution algorithm. Finally, the proposed models are illustrated through a simple numerical example. The study results confirm and support the idea of giving the priority to the development of urban public transport, which is an effective way to achieve a sustainable urban transportation.

关键词： Multimodal network vehicle emission system optimization bi-level programming

Survival analysis of car travel time near a bus stop in developing countries

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Science china(Technological Sciences) 2012年第8期55卷 2355-2361页

作者： YANG XiaoBao gao ziyou GUO HongWei HUAN Mei moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong UniversityBeijing 100044China Department of transportation Engineering Beijing Institute of TechnologyBeijing 100081China

This paper presents an important investigation into car travel time affected by mixed traffic flow near a bus stop on the basis of survival analysis *** time data associated with mixed traffic characteristics near a bus stop were collected by video cameras.A hazard-based duration model was introduced to analyze the effects of mixed traffic flow on car travel *** results indicate that mixed traffic flow impacts car travel time *** the presence of bus berthing violation would delay car travel *** proposed model can be used to forecast temporal shifts in car travel time due to changes in mixed traffic *** influential factors related to mixed traffic flow should be given full consideration in the planning and designing of bus stops in developing countries.

关键词： survival analysis travel time duration model bus stop mixed traffic

Multiple flux difference effect in the lattice hydrodynamic model

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Chinese Physics B 2012年第2期21卷 210-217页

作者： Wang Tao gao Zi-You Zhao Xiao-Mei moe key laboratory for urban transportation complex systems theory and technology Beijing Jiaotong UniversityBeijing 100044China College of Automation&Electronic Engineering Qingdao University of Science&TechnologyQingdao 266042China

Considering the effect of multiple flux difference, an extended lattice model is proposed to improve the stability of traffic flow. The stability condition of the new model is obtained by using linear stability theory. The theoretical analysis result shows that considering the flux difference effect ahead can stabilize traffic flow. The nonlinear analysis is also conducted by using a reduetive perturbation method. The modified KdV （mKdV） equation near the critical point is derived and the kink antikink solution is obtained from the mKdV equation. Numerical simulation results show that the multiple flux difference effect can suppress the traffic jam considerably, which is in line with the analytical result.

关键词： flux difference lattice hydrodynamic model traffic flow mKdV equation

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基于平均速度信息的城市交通路径诱导策略

合肥工业大学学报（自然科学版） 2018年第5期41卷 595-600页

作者：李浩丁中俊石琴姜锐高自友合肥工业大学汽车与交通工程学院安徽合肥230009 北京交通大学城市交通复杂系统理论与技术教育部重点实验室北京100044

文章采用元胞自动机模型对曼哈顿类型的城市交通系统进行建模。在该模型中,车辆选择平均旅行时间最短的路径进行行驶,而路段平均行驶时间由路段平均速度决定。车辆在网络中随机地产生目的地。通过计算机模拟能够观察到,该路径诱导策略... 详细信息

文章采用元胞自动机模型对曼哈顿类型的城市交通系统进行建模。在该模型中,车辆选择平均旅行时间最短的路径进行行驶,而路段平均行驶时间由路段平均速度决定。车辆在网络中随机地产生目的地。通过计算机模拟能够观察到,该路径诱导策略相比较于Li模型而言,系统的临界密度增大了,系统最大流量提高了,系统存在自由流、稳定流、完全堵塞3种状态。此外,该文考虑了城市网络中不同动态车比例对系统的影响,发现存在一个最优的动态车比例,使得系统车辆平均旅行时间最小,并进一步考虑了信号灯时长以及信息采集间隔对系统的影响。

关键词：元胞自动机城市交通流路径诱导策略

Photoelectron Spectroscopy and Density Functional theory Calculations of Binary VnC30/-(n=1-6) Clusters

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Chinese Journal of Chemical Physics 2022年第6期35卷 907-915,I0039-I0054,I0073页

作者： Jinyun Yuan Peng Wang Xiling xu Yonghui Zhang Linghao He Hong-Guang xu gao-Lei Hou Wei-Jun Zheng School of Material and Chemical Engineering Zhengzhou University of Light IndustryZhengzhou 450002China beijing National laboratory for Molecular Sciences State Key Laboratory of Molecular Reaction DynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China Physical Science laboratory Huairou National Comprehensive Science CenterBeijing 101400China moe key laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of PhysicsXi'an Jiaotong UniversityXi'an 710049China

Transition metal carbides have been shown to exhibit good catalytic performance that depends on their compositions and morphologies,and understanding such catalytic properties requires knowledge of their precise geometry,determination of which is challenging,particularly for clusters formed by multiple *** this study,we investigate the geometries and electronic structures of binary V_(n)C_(3)-(n=1-6)clusters and their neutrals using photoelectron spectroscopy and theoretical calculations based on density functional *** adiabatic detachment energies of V_(n)C_(3)-,or equally,the electron affinities of V_(n)C_(3),have been determined from the measured photoelectron *** calculations reveal that the carbon atoms become separate when the number of V atoms increases in the clusters,i.e.,the C-C interactions present in small clusters are replaced by V-C and/or V-V interactions in larger *** further explore the composition dependent formation of cubic or cube-like structures in 8-atom VnCm(n+m=8)clusters.

关键词： Vanadium carbide cluster Photoelectron spectroscopy Density functional theory Cubic or cube-like structure