Adaptive congestion control in networks with multiple congested nodes

In this paper, an analytical method for a design of a congestion control scheme in packet switching network is presented This scheme is particularly suitable for implementation in ATM Switch Systems, for the support of the available bit rate (ABR) service in ATM networks The control method is rate based with a local feedback controller associated with each switch node. The controller is a generalization of the standard proportional-plus-derivative controller, with the difference that extra higher order derivative terms are involved to accommodate for delay in networks. It is shown that there exist a set of control gain that result in applying asymptotic stability of the linearized network model. The use of adaptive control for finding the state feedback gains for asymptotically stability is our main purposes. Since the proposed approach considers the case of multiple congested nodes, it stabilizes the entire links in the network

Skew-tree based multistage fuzzy controller for nonlinear systems

In this paper a multistage fuzzy controller is designed and implemented on the ball and beam system which is a well-known benchmark in the control area because of its nonlinear, unstable non-minimum phase behavior. The most important property of the proposed controller is its simplicity whiles it fully mimics human's actions for controlling this system. In comparison to classical controllers such as Linear Quadratic Regulator (LQR) or combinational controllers such as fuzzy proportional integrator (PI), the proposed controller makes the overall system more stable with a remarkable decrease in settling time. Furthermore it eliminates overshoots around the desired set point much better than mentioned controllers do. This leads to a very smooth movement of ball on the beam illustrated in some simulations