建造横张预应力混凝土桥梁的新构思

文章提出一个新的横张预应力混凝土梁桥建造工法,扩大了横张预应力混凝土的适用范围。该工法利用虚功原理和平衡构形概念,通过双榀对称侧立预制空心梁的方法,以接近普通钢筋混凝土的价值,可制作得预应力混凝土,进一步降低了预应力混凝土桥的建造难度,提高了施工的可靠性,具有一定的技术、经济和社会效益。     

一种基于多元Probit模型的随机网络配流加载算法

为了改善基于Logit模型的随机网络配流加载算法的两个不足之处,本文提出了基于正态分布的Probit模型的随机网络配流算法。假设路段的广义交通时间服从正态分布,然后用蒙特卡洛模拟法对提出的算法进行求解。最后,用一个简单的交通网络例子对提出的算法进行验证分析。在算法求解过程中,运用Matlab对路段广义交通时间随机抽样,再对网络进行全有全无分配,将交通流量分配到起终点间的每一O-D对的最短路径上。应用Probit模型进行配流加载,其路径选择概率更接近实际更加合理,是一种值得推广的交通配流加载模型。     

Global Solutions and Exponential Stability of Stochastic Functional Differential Equations with Infinite Delay

This paper proves that, under the local Lipschitz condition, the stochastic functional differential equations with infinite delay have global solutions without the linear growth condition. Furthermore, the pth moment exponential stability conditions are given. Finally, one example is presented to illustrate our theory.     

Evaluation of a bus passenger information system from the users’ point of view in the city of Thessaloniki, Greece

This paper presents an evaluation, from the users’ point of view, of an advanced Bus Passenger Real Time Information System, installed at the city of Thessaloniki, Greece. In addition to the methodological approach and the findings presented, the paper explores the greater framework of evaluation procedures in which these analyses should be embedded. In total, 300 questionnaires were returned; the survey aimed to define the basic components of users’ acceptance of the new system as well as socioeconomic issues related with the estimation of the payback period of the project. The survey findings are combined with several research results from recent resembled surveys conducted in the city in previous years.     

Evaluation of the effect of cooperative infrastructure-to-vehicle systems on driver behavior

In-vehicle technologies and co-operative services have potential to ease congestion problems and improve traffic safety. This paper investigates the impact of infrastructure-to-vehicle co-operative systems, case of CO-OPerative SystEms for Intelligent Road Safety (COOPERS), on driver behavior. Thirty-five test drivers drove an instrumented vehicle, twice, with and without the system. Data related to driving behavior, physiological measurements, and user acceptance was collected. A macro-level approach was used to evaluate the potential impact of such systems on driver behavior and traffic safety. The results in terms of speeds, following gaps, and physiological measurements indicate a positive impact. Furthermore, drivers’ opinions show that the system is in general acceptable and useful.     

水翼艇纵向运动多变量随机最优控制仿真

基于随机控制理论，针对全浸式水翼艇的多变量随机控制方法进行探讨，并着重分析水翼艇的纵向运动姿态的随机最优控制。首先，依据动力学原理对其运动方程的建立和线性化进行了推导。其次，利用线性卡尔曼滤波器对其纵向运动姿态进行估计，依据LOG性能指标构造了最优控制规律。通过施加控制前后状态的比较，可以看出，应用随机最优控制的方法，对水翼艇的纵向运动进行控制取得了良好的效果。     

利用JSF开发Web页面

提出了一种新的基于JSF的Web页面开发方法,介绍了JSF技术及其特点,并结合实例展示如何开发JSF用户界面.最后分析了JSF技术优点及应用前景.     

The Hamilton–Jacobi partial differential equation and the three representations of traffic flow

This paper applies the theory of Hamilton–Jacobi partial differential equations to the case of first-order traffic flow models. The traffic flow surface is analyzed with respect to the three 2-dimensional coordinate systems arising in the space of vehicle number, time and distance. In each case, the solution to the initial and boundary value problems are presented. Explicit solution methods and examples are shown for the triangular flow-density diagram case. This unveils new models and shows how a number of existing models are cast as special cases.     

Stochastic dynamic switching in fixed and flexible transit services as market entry-exit real options

The first analytical stochastic and dynamic model for optimizing transit service switching is proposed for “smart transit” applications and for operating shared autonomous transit fleets. The model assumes a region that requires many-to-one last mile transit service either with fixed-route buses or flexible-route, on-demand buses. The demand density evolves continuously over time as an Ornstein-Uhlenbeck process. The optimal policy is determined by solving the switching problem as a market entry and exit real options model. Analysis using the model on a benchmark computational example illustrates the presence of a hysteresis effect, an indifference band that is sensitive to transportation system state and demand parameters, as well as the presence of switching thresholds that exhibit asymmetric sensitivities to transportation system conditions. The proposed policy is computationally compared in a 24-hour simulation to a “perfect information” set of decisions and a myopic policy that has been dominant in the flexible transit literature, with results that suggest the proposed policy can reduce by up to 72% of the excess cost in the myopic policy. Computational experiments of the “modular vehicle” policy demonstrate the existence of an option premium for having flexibility to switch between two vehicle sizes.