This paper presents first a performance analysis of the recently developed Minimal Resource Allocating Network (MRAN) algorithm for on-line identification of nonlinear dynamic systems. Using nonlinear time invariant and time varying identification benchmark problems, MRAN's performance is compared with the recently proposed On-line Structural Adaptive Hybrid Learning (ONSAHL) algorithm of Junge and Unbehauen. The results indicate that MRAN realizes networks using fewer hidden neurons than ONSAHL algorithm with better approximation accuracy. Next, methods for improving the run time performance of MRAN for real time identification of the nonlinear systems are developed. An extension to MRAN referred to as the Extended Minimum Resource Allocating Network (EMRAN) which utilizes a winner neuron strategy is highlighted. This modification reduces the computation load for MRAN and leads to considerable reduction in the learning time with only a slight increase in the approximation error. Using the same benchmark problems, the results show that EMRAN is well suited for fast on-line identification of nonlinear plants.
Abstract-This paper addresses preamble-based low complexity synchronization, channel estimation and equalization for Zero-padded (ZP) MB-OFDM based UWB systems. The proposed synchronization method consists of sync detection, coarse timing estimation, fine timing estimation, and oscillator frequency offset estimation. The distinctive features of MB-OFDM systems and the interplay between the timing and carrier frequency hopping at the receiver are judiciously incorporated in the proposed synchronization method. In order to apply the low complexity one-tap frequency-domain equalizer, the required circular convolution property of the received signal is obtained by means of an overlap-add method after the frequency offset compensation. The proposed low complexity channel estimator for each band is developed by first averaging the over-lapadded received preamble symbols within the same band and then applying time-domain least-squares method followed by the discrete Fourier transform. We develop an MMSE equalizer and its approximate version with low complexity. We also derive the probability density functions of the UWB channel path delays, and using them we present several optimization criteria for our proposed synchronization, channel estimation, and equalization. The effectiveness of our proposed methods and optimization criteria are confirmed by computer simulation results.
This paper introduces an electric power fault recorder integrated analyzing & application system, which interconnects digital fault recorders of several substations and power houses that are widespread in Jiangxi province of China and has the fault information gathered, processed, transmitted, shared and utilized automatically and effectively. A method based on the Newton iterative algorithm for precise fault data analysis was introduced into this system. In addition to realize the conventional analysis functions that are provided by similar systems, this system realizes extended functions of flexible protection action judgment. Besides, functions of formula editor and protective relaying testing simulation have been added and provide a novel approach for the comprehensive fault analysis applications. This system is now running steadily at the dispatch center of Jiangxi Province. The good results obtained reveal the superiority and effectiveness of this system.
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