切换服务系统的稳定性及交叉口信号配时

Stability of switched server system and signal timing of intersection

中文关键词  混杂系统  切换服务系统  周期解  稳定性  交叉口  交通控制

英文关键词  hybrid systems  switched server system  periodic solution  stability  intersections  traffic control

中文摘要

      当缓冲器内工作量较大时, 服务器的“固定顺序清空切换”服务策略使得清空缓冲器内工作量需要较长时间, 从而其他缓冲器未能及时得到服务. 为此本文提出服务器“带服务时间上限的固定顺序切换”服务策略, 服务器在该服务策略下分配给每个缓冲器服务时间上限, 以保证各缓冲器公平地得到服务. 在满足缓冲器总负荷小于各缓冲器服务时间调整因子的最小值与最大值之比的条件下, 证明了所提出服务器服务策略下的切换服务系统是周期稳定的. 进一步将交叉口信号配时建模为切换服务系统, 并应用所提出的服务器服务策略研究了交叉口信号配时策略. 通过对交叉口实际数据的仿真验证了本文方法的有效性.

英文摘要

      For a buffer with a large amount of work, under the service strategy ‘empty buffers in a fixed sequence', the server has to take a longer time to empty this buffer, making other buffers unable to be served timely. Motivated by this problem, we propose the service strategy called ‘empty buffers in a fixed sequence with upper limits of service-time'. The server assigns each buffer an upper limit of service-time such that each buffer can be served fairly. It is proved that switched server system under the proposed service strategy is periodically stable when the total buffer load is less than the ratio of the minimum to the maximum of the buffer service-time adjustment factors. Furthermore, the signal timing of an intersection is modeled as a switched server system, and the proposed service strategy is directly applied to the signal timing of the intersection. The effectiveness of the proposed methods is verified by the simulation for an intersection based on practical data.