基于三种非机动车过街方式的交叉口通行效率研究

为了寻求两相位交叉口最佳的过街方式,文章就交叉口人均延误和交叉口车道通行能力两个方面展开研究,基于三种非机动车过街方式下的延误模型、车道通行能力模型,以人均延误和通行能力为判别指标,对比三种非机动车过街方式的交叉口人均延误和交叉口车道通行能力,取延误最小者或车道通行能力最大者为最优非机动车过街方式。具体应用中,以南京市两相位交叉口的调查流量为基础,计算出不同时段下延误最小的非机动车过街方式和交叉口车道通行能力最大的非机动车过街方式。结果表明:停车线后移方式下的交叉口车道通行能力最大,交叉口延误需要根据时段流量来确定最小延误对应的非机动车过街方式。研究可为选择合适的非机动车交叉口过街方式提供参考借鉴。

Stability of Nonlinear Wave of Kadomtsev-Petviashvili-Type Equation

For ion-acoustic waves in a plasma with non-isothermal electrons, the MKP equation is its governing equation. The instability of a soliton solution of MKP equation to two-dimensional long-wavelength perturbations is investigated up to the third order. It indicates that the one-soliton solution of MKP equation is unstable if v = -1 wheras it is stable if v = 1 until the third order approximation has been considered.

Dissipation of Nonlinear Wave in Inhomogeneous Dust Plasma Crystal

A Korteweg-de Vires-type （KdV-type） equation and a modified Nonlinear Schrodinger equation （NLSE） for the dust lattice wave （DLW） are derived in a weakly inhomogeneous dust plasma crystal. It seems that the amplitude and the velocity of the dust lattice solitary waves decay exponentiaJly with increasing time in a dust lattice. The modulational instability of this dust lattice envelope waves is investigated as well. It is found that the waves are modulational stable under certain conditions. On the other hand, the waves are modulationaJ unstable if the conditions are not satisfied.

信号交叉口进口车道饱和流率估计方法

为准确估计信号交叉口进口车道的饱和流率,将高峰期获取的车头时距采用时间序列表达;基于PP检验构建稳态检验算法,剔除绿灯显示期间进口车道的异常车头时距,以获取饱和车头时距,采用饱和车头时距的均值估计饱和流率。以长春市某典型信号交叉口3条直行车道为例对本文方法进行验证,并与HCM方法进行对比。结果表明:本文方法能准确识别出饱和车头时距;饱和流率的估计值为1700~1900 pcu/h,高于HCM方法所得到的饱和流率估计值。

基于三种过街方式的两相位信号交叉口延误

从交通效率的角度出发,寻求两相位交叉口人均延误最小的过街方式,以车辆到达-驶离曲线为依据,结合韦伯斯特机动车延误模型,建立了非机动车传统过街、二次过街及机动车停车线后移3种延误模型。以人均延误为判别指标,描述了3种非机动车过街方式人均延误与车流流量的变化关系。通过对比3种机动车过街方式的交叉口人均延误,取延误最小者作为最优方式,为选择合适的非机动车交叉口过街方式提供了参考。