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Latent semantic analysis (LSA) has been used in several intelligent tutoring systems(ITS's) for assessing students' learning by evaluating their answers to questions in the tutoring domain. It is based on word-document co-occurrence statistics in the training corpus and a dimensionality reduction technique. However , it doesn't consider the word-order or(More)
—In this paper, we present a method of parameter estimation for a class of problems where the desired signal is embedded in colored noise with unknown covariance. The new algorithm is a variation of the covariance differencing scheme proposed by Paulraj and Kailath. Unlike the previous method, however, the proposed algorithm does not require multiple(More)
—The problem of providing robustness to the conventional narrow-band uniform linear array configuration so as to handle wide-band and moving jammers is addressed here. This robustness is achieved via the use of derivative constraints in jammer directions. However, since the jammer directions are not known a priori, these constraints are incorporated with a(More)
This paper proposes a new method of estimating both biorthogonal compactly supported as well as semi-orthogonal infinitely/compactly supported wavelet from a given signal. The method is based on maximizing projection of the given signal onto successive scaling subspace. This results in minimization of energy of signal in the wavelet subspace. The idea used(More)
—The problem of modified ML estimation of DOA's of multiple source signals incident on a uniform linear array (ULA) in the presence of unknown, spatially correlated Gaussian noise is addressed here. Unlike previous work, the proposed method does not impose any structural constraints or parameterization of the signal and noise covariances. It is shown that(More)
This paper presents a new approach for the estimation of wavelets that is matched to a given signal in the statistical sense. Based on this approach, a number of new methods to estimate statistically matched wavelets are proposed. The paper first proposes a new method for the estimation of statistically matched two-band compactly supported biorthogonal(More)
—Most of the existing techniques for DOA estimation of broadband sources use both spatial and temporal modeling. This may lead to increased complexity besides a large algorithmic delay. In this paper, we propose a technique that employs only spatial information in the form of a single spatial array covariance matrix. Assuming the source to have an ideal(More)
50 100 150 200 250 300 NUMBER OF DATA POINTS Fig. 1. Computational cost flops/iteration for stepped sine response mod-eling for transfer functions with 2, 4, and 6 system poles. 20 30 SNR (dB) 10 20 30 SNR (dB) Fig. 2. Pole parameter estimate SNR (0) = 10 logul[0 2 /MSE(0)] versus the observed data SNR in decibels. Five hundred Monte Carlo trials. N = 16.(More)