The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Our aim is to evaluate fundamental parameters from the analysis of the electromagnetic spectra of stars. We may use 103–105 spectra; each spectrum being a vector with 102–104 coordinates. We thus face the so-called “curse of dimensionality”. We look for a method to reduce the size of this data-space, keeping only the most relevant information. As a reference method, we use principal component analysis...
Randomized algorithms are a useful tool for analyzing the performance of complex uncertain systems. Their implementation requires the generation of a large number N of random samples representing the uncertainty scenarios, and the corresponding evaluation of system performance. When N is very large and/or performance evaluation is costly or time consuming, it can be necessary to distribute the computational...
In this paper, we study the data driven identification of large scale dynamic systems that exhibit complex behavior that manifests itself as multi-modal dynamic behavior. As the first result, we present the identification approach of autonomous stochastic dynamic systems. The resulting model is hybrid in nature. We detect the multi-modal dynamics as well as local dynamics within each mode, thus providing...
The Two-Stage Algorithm (TSA) has been extensively used and adapted for the identification of block-oriented nonlinear systems including Hammerstein systems. This paper revisits an optimality result established by Bai in 1998 showing that the TSA provides the optimal estimation of a bilinearly parameterized Hammerstein system in the sense of a weighted nonlinear least-squares (LS) criterion formulated...
In this paper, a new approach of blind estimation of subcarrier number based on multiple signal classification (MUSIC) algorithm is proposed for MB-OFDM ultra-wide band (UWB) communications system. The proposed eigenvalue-construct method only using signal autocorrelation of orthogonal frequency-division multiplexing (OFDM) symbols estimates the number of subcarriers. The computer simulations show...
In this work, we present a new robust method for calibrating the vision system. With the known intrinsic parameters of the camera, we show that its motion parameters, in terms of translation vector and rotation matrix, can be determined automatically from plane-based homography. In this method, a closed-form solution is provided to increase the computational efficiency and arbitrary motion is allowed...
To estimate carrier frequency offset, a polynomial-rooting algorithm is proposed for symbols with constant modulus in OFDM systems. This algorithm makes use of the orthogonal subspace of the squared spectrum vector of the channel. Among the group of non-iterative methods, the algorithm offers the best accuracy.
Eigendecomposition has been used to classify three-dimensional objects from two-dimensional images in a variety of computer vision and robotics applications. The biggest on-line computational expense associated with using eigendecomposition is the determination of the closest point on an image manifold embedded in a high-dimensional space. The dimensionality and complexity of the space is a result...
The fingerprint quality is considered as a good predictor for fingerprint recognition performance and knowing the fingerprint quality in advance is useful to improve the fingerprint recognition performance. The existing fingerprint quality estimation systems are all designed for minutiae-based fingerprint recognition system. But with the obvious advantage and widespread of ROI-based fingerprint recognition...
The problem of estimating the intrinsic dimensionality of certain point clouds is of interest in many applications in statistics and analysis of high-dimensional data sets. Our setting is the following: the points are sampled from a manifold M of dimension k, embedded in RopfD, with k Lt D, and corrupted by D-dimensional noise. When M is a linear manifold (hyperplane), one may analyse this situation...
A novel algorithm for effective channel order estimation, NECOE, is proposed in this paper, which exploits the relation of the channel order and a special matrix constructed by ldquonoiserdquo subspace, and derives a new theorem about the special matrix. Based on the new theorem, the novel algorithm estimates the channel order by modifying the dimension of ldquonoiserdquo subspace. Simulations prove...
This paper proposes a computationally efficient spreading-waveform-estimation method for the non-symbol-periodic Direct Sequence Spread Spectrum (DS-SS) signals. The method is a low SNR unconditional maximum likelihood (UML) estimation algorithm. It works under the assumption of uniformly distributed transmission delay, which may cause mismatch in the real-world model. Equivalence exists between the...
The problem of estimating parameter of LTI state-space system is addressed in this paper. A modified nonlinear least square(NNLS) method is proposed to the optimization of output error cost function. The nonuniqueness of the fully parameterized state-space is considered and the parameter update is restricted to the directions that change the input-output behavior of the system. Simulation studies...
In this paper we consider a network that is trying to reach consensus over the occurrence of an event while communicating over additive white Gaussian noise (AWGN) channels. We characterize the impact of different link qualities and network connectivity on consensus performance by analyzing both the asymptotic and transient behaviors. More specifically, we derive a tight approximation for the second...
In this paper, we deal with the estimation of the ergodic capacity of large MIMO systems, using training sequences whose lengths are of the same order of magnitude than the number of antennas. In this context, the traditional estimator becomes inconsistent. Following the ideas developed by Girko in the context of the so-called theory of G-estimation, we propose a new estimator. We analyze its asymptotic...
To accurately describe the high frequency electromagnetic scattering of the radar objects, the full-polarization GTD model is established based on the combination of the full-polarization information and the geometric theory of diffraction model. Meanwhile, A novel method, MUSIC based on polarization linear variation method (PL-MUSIC) is proposed. The estimation accuracy is improved and the computational...
The rank-revealing QR factorization (RRQR) is a valuable tool in numerical linear algebra because it provides accurate information about rank and numerical null-space. In this paper, we addressed the problem of estimating the time delay and the frequencies of noisy sinusoidal signals received at two spatially separated sensors using the well known RRQR, subspace decomposition technique. Although eigenvalue...
In this paper, in order to realize the image enlargement with high performance, we propose a new enlargement method, which restores high-frequency components lost in the interpolation-based methods, by using high-frequency estimation. The estimation is based on the eigenspace method proposed by Amano et al. The proposed enlargement method can generate lost high-frequency components by using pairs...
In recent work, we proposed some new ideas for efficient sequential importance sampling in the context of particle filtering. These were specifically designed for problems with multimodal posteriors (particularly those with multimodal likelihoods) and with very large dimensions. In this work, we demonstrate the use of similar ideas to improve the performance of importance sampling (IS) in static problems...
This paper exploits rotation invariance of matrix pencil based on two parallel uniform linear polarization sensitive arrays, and eigenvalues and the corresponding eigenvectors of the matrix pencil are the rotation matrix and time-space-polarization steering vector of the subarray, respectively. The eigenvalues and steering vector can be used to estimate frequency, two-dimensional angles and polarization...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.