This study mainly analyzed problems in ecological landscape and traffic safety of urban roads, and in view of these problems, proposed the design concepts, principles and focuses of urban road eco-landscape ensuring t...This study mainly analyzed problems in ecological landscape and traffic safety of urban roads, and in view of these problems, proposed the design concepts, principles and focuses of urban road eco-landscape ensuring traffic safety.展开更多
In this paper, the authors first analyse the problems existing in the situation of land use, structure of travel mode and road network by applying the basic principle of traffic engineering and system engineering meth...In this paper, the authors first analyse the problems existing in the situation of land use, structure of travel mode and road network by applying the basic principle of traffic engineering and system engineering methods. Then, the authors make it clear the strategies to be adopted for solving the existing traffic problems in the ancient urban area of Suzhou(AUAS), namely insisting on the goal based strategy; the strategy to develop the public transit system in priority and decreasing the demand on cars from the view point of land use strategy. On the basis of such analysis the authors put forth proposals about major measures to be taken to improve traffic conditions of the AUAS, such as construction of express artery ring around the ancient city, appropriate transformation of the roads in the AUAS and rational distribution of car parking areas at the outskirt, which are of positive significance in guiding the protection of the AUAS and transportation construction. In this paper, specialized software is used to establish criteria for the construction scale and extent analysis and evaluation of the ancient city construction project, which is of some reference significance to the transformation of old urban areas in other cities.展开更多
This paper investigates the dynamical behaviour of network traffic flow. Assume that trip rates may be influenced by the level of service on the network and travellers are willing to take a faster route. A discrete dy...This paper investigates the dynamical behaviour of network traffic flow. Assume that trip rates may be influenced by the level of service on the network and travellers are willing to take a faster route. A discrete dynamical model for the day-to-day adjustment process of route choice is presented. The model is then applied to a simple network for analysing the day-to-day behaviours of network flow. It finds that equilibrium is arrived if network flow consists of travellers not very sensitive to the differences of travel cost. Oscillations and chaos of network traffic flow are also found when travellers are sensitive to the travel cost and travel demand in a simple network.展开更多
In this note, we consider the interactions of elementary waves for the traffic flow model proposed by Aw and Rascle when the vacuum is not involved. The solutions are obtained constructively and globally when the init...In this note, we consider the interactions of elementary waves for the traffic flow model proposed by Aw and Rascle when the vacuum is not involved. The solutions are obtained constructively and globally when the initial data consist of three pieces of constant states. Furthermore, it can be found that the Riemann solutions are stable with respect to such small perturbations of the initial data in this particular situation by investigating the limits of the solutions as the perturbed parameter ε goes to zero.展开更多
In the traffic equilibrium problem, we introduce capacity constraints of arcs, extend Beckmann’s formula to include these constraints, and give an algorithm for traffic equilibrium flows with capacity constraints on ...In the traffic equilibrium problem, we introduce capacity constraints of arcs, extend Beckmann’s formula to include these constraints, and give an algorithm for traffic equilibrium flows with capacity constraints on arcs. Using an example, we illustrate the application of the algorithm and show that Beckmann’s formula is a sufficient condition only, not a necessary condition, for traffic equilibrium with capacity constraints of arcs.展开更多
In this article, we consider the multiclass network equilibrium problems. A so called strongly valid toll can support any multiclass user equilibrium flow pattern as a system minimum when the system objective function...In this article, we consider the multiclass network equilibrium problems. A so called strongly valid toll can support any multiclass user equilibrium flow pattern as a system minimum when the system objective function is measured by total emission. Using Hoffman lemma and exact penalization method, we provide the existence of strongly valid tolls for multiclass network equilibrium problems.展开更多
In this paper, we focus on the theoretical and numerical aspects of network problems. For an illustration, we consider the urban traffic problems. And our effort is concentrated on the numerical questions to locate th...In this paper, we focus on the theoretical and numerical aspects of network problems. For an illustration, we consider the urban traffic problems. And our effort is concentrated on the numerical questions to locate the optimal network in a given domain (for example a town). Mainly, our aim is to find the network so as the distance between the population position and the network is minimized. Another problem that we are interested is to give an numerical approach of the Monge and Kantorovitch problems. In the literature, many formulations (see for example [1-4]) have not yet practical applications which deal with the permutation of points. Let us mention interesting numerical works due to E. Oudet begun since at least in 2002. He used genetic algorithms to identify optimal network (see [5]). In this paper we introduce a new reformulation of the problem by introducing permutations . And some examples, based on realistic scenarios, are solved.展开更多
在经典车辆路径问题(vehicle routing problem,VRP)的基础上增加了客户要求访问的时间窗约束,以车辆行驶路径最短和使用车辆数最小为目标,建立了不确定车辆数的多约束车辆路径问题(multi-constraint vehicle routing problem with varia...在经典车辆路径问题(vehicle routing problem,VRP)的基础上增加了客户要求访问的时间窗约束,以车辆行驶路径最短和使用车辆数最小为目标,建立了不确定车辆数的多约束车辆路径问题(multi-constraint vehicle routing problem with variable fleets,MVRP-VF)的数学模型。引入遗传算法的交叉操作以及大规模邻域搜索算法中的破坏算子和修复算子,重新定义了基本灰狼优化算法(grey wolf optimizer,GWO)的操作算子,优化了GWO的寻优机制,从而设计出用于求解MVRP-VF问题的混合灰狼优化算法(hybrid grey wolf optimizer,HGWO)。通过仿真实验与其他参考文献中的算法求解结果进行比较,验证了HGWO求解该类问题的有效性与可行性。展开更多
文摘This study mainly analyzed problems in ecological landscape and traffic safety of urban roads, and in view of these problems, proposed the design concepts, principles and focuses of urban road eco-landscape ensuring traffic safety.
文摘In this paper, the authors first analyse the problems existing in the situation of land use, structure of travel mode and road network by applying the basic principle of traffic engineering and system engineering methods. Then, the authors make it clear the strategies to be adopted for solving the existing traffic problems in the ancient urban area of Suzhou(AUAS), namely insisting on the goal based strategy; the strategy to develop the public transit system in priority and decreasing the demand on cars from the view point of land use strategy. On the basis of such analysis the authors put forth proposals about major measures to be taken to improve traffic conditions of the AUAS, such as construction of express artery ring around the ancient city, appropriate transformation of the roads in the AUAS and rational distribution of car parking areas at the outskirt, which are of positive significance in guiding the protection of the AUAS and transportation construction. In this paper, specialized software is used to establish criteria for the construction scale and extent analysis and evaluation of the ancient city construction project, which is of some reference significance to the transformation of old urban areas in other cities.
文摘This paper investigates the dynamical behaviour of network traffic flow. Assume that trip rates may be influenced by the level of service on the network and travellers are willing to take a faster route. A discrete dynamical model for the day-to-day adjustment process of route choice is presented. The model is then applied to a simple network for analysing the day-to-day behaviours of network flow. It finds that equilibrium is arrived if network flow consists of travellers not very sensitive to the differences of travel cost. Oscillations and chaos of network traffic flow are also found when travellers are sensitive to the travel cost and travel demand in a simple network.
基金Sponsored by National Natural Science Foundation of China (10901077)China Postdoctoral Science Foundation (201003504+1 种基金 20090451089)Shandong Provincial Doctoral Foundation (BS2010SF006)
文摘In this note, we consider the interactions of elementary waves for the traffic flow model proposed by Aw and Rascle when the vacuum is not involved. The solutions are obtained constructively and globally when the initial data consist of three pieces of constant states. Furthermore, it can be found that the Riemann solutions are stable with respect to such small perturbations of the initial data in this particular situation by investigating the limits of the solutions as the perturbed parameter ε goes to zero.
文摘In the traffic equilibrium problem, we introduce capacity constraints of arcs, extend Beckmann’s formula to include these constraints, and give an algorithm for traffic equilibrium flows with capacity constraints on arcs. Using an example, we illustrate the application of the algorithm and show that Beckmann’s formula is a sufficient condition only, not a necessary condition, for traffic equilibrium with capacity constraints of arcs.
基金supported by the National Natural Science Foundation of China NSFC:71071035
文摘In this article, we consider the multiclass network equilibrium problems. A so called strongly valid toll can support any multiclass user equilibrium flow pattern as a system minimum when the system objective function is measured by total emission. Using Hoffman lemma and exact penalization method, we provide the existence of strongly valid tolls for multiclass network equilibrium problems.
文摘In this paper, we focus on the theoretical and numerical aspects of network problems. For an illustration, we consider the urban traffic problems. And our effort is concentrated on the numerical questions to locate the optimal network in a given domain (for example a town). Mainly, our aim is to find the network so as the distance between the population position and the network is minimized. Another problem that we are interested is to give an numerical approach of the Monge and Kantorovitch problems. In the literature, many formulations (see for example [1-4]) have not yet practical applications which deal with the permutation of points. Let us mention interesting numerical works due to E. Oudet begun since at least in 2002. He used genetic algorithms to identify optimal network (see [5]). In this paper we introduce a new reformulation of the problem by introducing permutations . And some examples, based on realistic scenarios, are solved.
文摘在经典车辆路径问题(vehicle routing problem,VRP)的基础上增加了客户要求访问的时间窗约束,以车辆行驶路径最短和使用车辆数最小为目标,建立了不确定车辆数的多约束车辆路径问题(multi-constraint vehicle routing problem with variable fleets,MVRP-VF)的数学模型。引入遗传算法的交叉操作以及大规模邻域搜索算法中的破坏算子和修复算子,重新定义了基本灰狼优化算法(grey wolf optimizer,GWO)的操作算子,优化了GWO的寻优机制,从而设计出用于求解MVRP-VF问题的混合灰狼优化算法(hybrid grey wolf optimizer,HGWO)。通过仿真实验与其他参考文献中的算法求解结果进行比较,验证了HGWO求解该类问题的有效性与可行性。
