A new regionalization algorithm is presented to improve wide-area backup protection (WABP) of the power system. This method divides the power system into several protection zones based on the proposed optimal measurement device (MD) placement and electrical distances. The modified binary particle swarm optimization is used to achieve the optimal MD placement in the first step. Next, the power system is divided into small protection zones (SPZ) using the topology matrix of the power system and MD locations. Finally, the SPZs are combined to accomplish the main protection zones and protection centers according to electrical distances, degree of buses, and communication link constraints. The introduced regionalization formulation can help provide a rapid and secure WABP for power systems. This method was applied to several IEEE standard test systems, and the simulation results demonstrated the effectiveness of the proposed scheme.

In recent years, performance of the Mobile Ad-Hoc Network (MANET) has become an important research area in the wireless networks community. MANET consists of clusters of Mobile Nodes (MNs) on the access network that could be connected to other clusters through a fixed backbone of routers. The access link contention can severely constrain the end-to-end throughput of the path between a pair of source and destination MNs connected through the backbone. In this paper, we propose an integrated routing system for MANET that includes the backbone paths and the ad-hoc paths formed as a result of direct communication among MNs without going through the backbone. In our proposed routing system, an alternative ad-hoc path can be used only when the primary backbone path is severely constrained due to access links contention. We also propose a scheme for making the MN aware of link quality measures, and incorporate throughput metric in the core of AODV. We implemented the proposed routing system in the OPNET simulator, and evaluated the performance of our scheme under a variety of conditions. Simulation results show that the alternative ad-hoc path is effective in delivering higher throughput when the backbone path is severely constrained.

The backup 2-median location problem on a tree T is to deploy two servers at the vertices such that the expected sum of distances from all vertices to the set of functioning servers is minimum. In this paper, we investigate the backup 2-median location problem on tree networks with trapezoidal interval type-2 fuzzy weights. We first, present  a new  method for comparing generalized trapezoidal fuzzy numbers and then develop it for trapezoidal interval type-2 fuzzy numbers. Then numerical examples are given to compare the proposed methods with other existing  methods. Finally, we apply our ranking method to  solve the the backup 2-median location problem on a tree network with trapezoidal interval type-2 fuzzy weights.

Due to limitations in computing resources of mobile nodes, Mobile Ad-hoc Networks (MANETs) are very fault-prone. So far, redundancy at different levels of the network has been considered an efficient strategy to enhance the fault-tolerance of networks. Indeed, ad-hoc networks are extremely redundant; therefore, natural redundancy to fault tolerance enhancement has a great impact on the network performance. In this paper, a fault tolerant algorithm for MANETs has been proposed that by assigning backup node(s) to each node tries to increase in fault-tolerance. For this reason, the proposed algorithm chooses the backup nodes from among those nodes having the same movement route. The nodes movement route can be determined or predicted through the backup nodes table. Choosing backup nodes is done based on the time of nodes adjacency. Experimental results taken from NS-2 simulator indicated that in comparison to other algorithms, the proposed algorithm increases by 1) the package delivery rate in relation to the percentage of fault, and 2) the package delivery rate in relation to various mobile nodes’ pause time.