本文在分析城市交通信号控制研究现状和交叉*通信号控制原理、评价方 法的基础上，设计了单交叉*通信号两级模糊控制系统。分级模糊控制能有效 减少模糊规则数，易于提取模糊规则，适合于交通状况复杂的城市交叉*通信 号控制。但它存在难以由人工合理定义全部模糊隶属度函数的问题。为此本文进 一步采用遗传算法对两级模糊控制器中模糊隶属度函数进行优化。本文提出的方 法具有分级模糊控制的优点，同时可以使模糊隶属度的选取更为合理，获得更好 的控制效果。对一个四相位单交叉口，利用MA

A semi blind technique for estimating the carrier frequency offset in OFDM communication systems is presented in this paper. The fractional and integer frequency offsets are esti-mated by employing a few null subcarriers in the rst OFDM sy

It is widely agreed that optimal procurement of reserves,with explicit consideration of systemcontingencies, can improve reliability and economic efficiency in power systems.With increasing penetration of uncertain generation resources, this optimal