Showing 3 results for Interpolation
A. Sayadiyan, K. Badi, M. Moin and N. Moghadam,
Volume 23, Issue 2 (1-2005)
Abstract
Hidden Markov Model is a popular statisical method that is used in continious and discrete speech recognition. The probability density function of observation vectors in each state is estimated with discrete density or continious density modeling. The performance (in correct word recognition rate) of continious density is higher than discrete density HMM, but its computation complexity is very high, especially in very large discrete utterance recognition problems. For real time implementation of very large discrete utterance recognition, we must use discrete density HMM (DDHMM). To increase the performance of DDHMM, one usual solution is fuzzy interpolation. In this study, we present a new method named Gaussian interpolation. We implemented and compared the performance of two types of interpolation methods for 1500 Persian speech command words. Results show that precision and flexibility of Gaussian interpolation is better thanthose of the fuzzy interpolation.
B. Saghafian, S. Rahimi Bandarabadi, H. Taheri Shahraeeni and J. Ghayoomian,
Volume 24, Issue 1 (7-2005)
Abstract
Rainfall is one of the most important climatic variables in the hydrology cycle. In flood estimation as well as environmental pollution studies in medium to large watersheds not only mus temporal pattern of rainfall t be known, but also the knowledge of its spatial distribution is required. Estimation of daily rainfall distribution without comparison and selection of
suitable methods may lead to errors in input parameters of rainfall – runoff models. Interpolation methods are among the techniques for estimating spatial distribution of rainfall. In this study, Thin Plate Smoothing Splines (TPSS), Weighted Moving Average (WMA) and Kriging are applied to estimate spatial daily rainfall in the southwest of Iran. Cross validation technique is used for comparison and evaluation of the methods. The results of analysis with two different station density showed that the TPSS method with power of 2 is the most accurate method in estimating daily rainfall. Zoning of the region also increased the interpolation accuracy. Generally speaking, division of the region based on cluster analysis improves accuracy compared with division by inter basin boundaries
H.a. Abyaneh, R. Mohammadi H. Torkaman, F. Razavi, and E. Afjei,
Volume 27, Issue 2 (1-2009)
Abstract
All algorithms for impedance calculation use an analog-to-digital converter. The high accuracy of the impedance seen by a distance relay is an important factor in the correct isolation of the faulty part of power systems. To achieve this, a novel
technique based on third order interpolation is used in this paper. According to this technique, the times and the values of the obtained samples are changed to real ones. To evaluate the new technique, it is applied to six digital distance algorithms, namely, Discrete Fourier Transform (DFT), Half-cycle Discrete Fourier Transform, Least Square, Mann-Morrison, Least Square with Delete Dc, and Prodar70. The technique is found to be capable of accurately computing the impedance in the algorithms mentioned. Comparisons are made among the results to show the efficiency of the new technique for decreasing errors in all algorithms.
