In this paper, a new sphere decoding algorithm is introduced which is a modification of the Viterbo-Boutros (VB) algorithm. In the proposed algorithm, the problem of the initial selection of the search sphere radius in the VB algorithm has been removed, and furthermore, the speed of the algorithm is increased. To examine the performance of the proposed algorithm, we employ it in detection of signals in code division multiple access (CDMA) and multiple-input multiple-output (MIMO) systems. Computer simulations, by using the proposed algorithm, show a significant performance improvement with respect to other suboptimal detection methods

One of the main problems in high voltage networks is over voltages due to lightning. These over voltages, which are not possible to prevent, create problems where the insulating level of the equipment is not enough. Selecting a high insulating level will increase the costs and volume of the equipment. For the sake of decreasing insulating levels and their costs, it is necessary to control over voltages and lead them to earth by equipment like arresters. In this paper, over voltages, mostly due to lightning and its dangers to power networks, have been studied for: 1- The effect of arrester earthing resistance, 2- Tower footing resistance, 3- Capacitive voltage transformer and 4- Tower structure. An EMPT program has been used for simulation of a line and a substation of 230kv/123kv (Ahwaz-Omidieh) as a case study.