In this paper,we consider the average-consensus problem with communication time delays and noisy links.We analyze two different cases of coupling topologies：fixed and switching topologies.By utilizing the stability theory of the stochastic differential equations,we analytically show that the average consensus could be achieved almost surely with the perturbation of noise and the communication time delays even if the time delay is time-varying.The theoretical results show that multi-agent systems can tolerate relatively large time delays if the noise is weak,and they can tolerate relatively strong noise if the time delays are low.The simulation results show that systems with strong noise intensities yield slow convergence.
针对无线体域网（wireless body area network,WBAN）结合云计算时的数据通信与用户隐私安全问题,提出使用多值和模糊方案（multi-valued and ambiguous scheme,MAS）解决云辅助WBAN中的数据安全问题。首先概述MAS算法,给出该算法的加密和推理过程;然后将该算法应用于云辅助WBAN,并证明该算法能有效保证云端与WBAN间的数据通信安全,同时结合现存的加密算法提供了一种实现该算法的实例;最后验证算法的效率,实验结果显示,输入数据从0~900 KB增加的过程中,算法的加密总时间始终保持在5 s以内,低于DES和AES算法,解密总时间大部分在22 s以内,优于DES和AES算法,该算法可以很好地用于解决云辅助WBAN的数据安全问题。
