交通流相变过程的能量谱分析

为研究交通流相变过程问题，对一维交通流进行元胞自动机模拟，进行截面车流率数据提取，并将数据经过离散的傅里叶变换进行能量谱分析．研究结果发现：在阻塞相，系统周期即为因采用周期边界条件而形成的交通激波周期；在高密度区所对应的同步交通流状态中，系统中仍然存在着周期性波动，该周期明显异于交通激波周期，因而其形成原因不能简单归结为周期边界条件的影响；在低密度区对应的自由流状态下，没有此类波动存在．

POWER SPECTRUM ANALYSIS ON THE PHASE CHANGING PROCESSES IN TRAFFIC FLOW

To investigate the phase changing processes in traffic flow, we simulated a single lane traffic flow using a cellular automation. By extracting the section flux data and using discrete Fourier transform method, we made the power spectrum analysis. From the result we foundthat in the phase of jam, there exists a same period as that of a traffic shockwave resulting from our using the periodic boundary conditions; in the phase of heavy synchronized flow with high road occupancy, there still exists some periodic waves which are very different from the traffic shockwave, and we could not attribute them to the periodic boundary conditions; in the phase of free flow under low road occupancy, no periodic waves exist.