This work investigates the design of beampatterns for frequency diverse arrays-multiple-input multiple-output (FDA-MIMO) in the range-angle plane, in order to improve the approximation of a desired beampattern. Recogn...
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This work investigates the design of beampatterns for frequency diverse arrays-multiple-input multiple-output (FDA-MIMO) in the range-angle plane, in order to improve the approximation of a desired beampattern. Recognizing that the energy radiated by the array cannot be locked at a fixed range and angle, the beampattern is designed for the equivalent beampattern at the receiving end, differing from the traditional emphasis on the transmit beampattern. The proposed scheme formulates the beampattern design as a minimization problem, where the cost function is defined as the squared error between the designed and the given beampatterns. The developed scheme is then implemented through an optimal selection of both the FDA frequency offsets and the receiver steering weights. To this end, an iterative algorithm with monotonic convergence is introduced to solve the resulting non-convex optimization problem involving a fourth-order polynomial objective function as well as multiple non-convex constraints. Numerical simulations verify the performance of the algorithm and show that the proposed scheme can efficiently concentrate the energy of the echo signal on the desired region in the range-angle plane.
This brief presents the global convergence behavior of an iterative algorithm used in the computation of a fairness index, named Biased Contribution Index (BCI). The BCI is used to maintain fairness in a cooperative c...
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This brief presents the global convergence behavior of an iterative algorithm used in the computation of a fairness index, named Biased Contribution Index (BCI). The BCI is used to maintain fairness in a cooperative computing system. It is expressed as a ratio of the first-order polynomials of the BCI of the other agents in the system. In this brief, first, we generalize the definition of the BCI, by expressing it as a ratio of fractional polynomials, then we prove the global convergence of the iterative method used in its solution. With the help of numerical examples, we explain the impact of the parameters used in the definition of BCI on its convergence.
In this paper, a modified alternately linear implicit (MALI) iteration method is derived for solving the non-symmetric coupled algebraic Riccati equation trix equations are fixed at each iteration step. In addition, t...
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In this paper, a modified alternately linear implicit (MALI) iteration method is derived for solving the non-symmetric coupled algebraic Riccati equation trix equations are fixed at each iteration step. In addition, the MALI iteration method utilizes a weighted average of the estimates in both the last step and current step to update the estimates in the next iteration step. Further, we give the convergence theory of the modified algorithm. Last, numerical examples demonstrate the effectiveness and feasibility of the derived algorithm.
The present article considers the estimation of functional product surface properties using the results of measuring areal surface texture parameters via morphological filtering. Under this method, a form of measureme...
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The present article considers the estimation of functional product surface properties using the results of measuring areal surface texture parameters via morphological filtering. Under this method, a form of measurement data representation is proposed to improve the efficiency of an algorithm for iterating over surface coordinates. It is shown that for wide implementation of areal morphological filtering in metrological practice, it is necessary to create an efficient filtering algorithm. In the work, an algorithm was developed relying on a matrix representation of morphological operations on surface coordinates. Different indexing of the primary surface and structuring element points was introduced. A sphere or flat segment was used as the structuring element. The performance of the developed algorithm is higher than that of some other algorithms due to the fact that all computations are performed by iterating over surface coordinates in a single pass without nested loops. The diagrams of algorithms for the morphological operations of dilation and erosion are given;these operations were used to construct closing and opening filters. Simulations performed for different datasets and a comparison with known morphological filtering algorithms confirmed the high efficiency of the developed algorithm. The obtained results can be applied in the analysis of the functional properties of product surfaces.
We consider the nonparametric estimation of the density function of an underlying random variable from a sequence of strongly mixing noisy observations. We develop a two-step estimation procedure to accomplish this ta...
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We consider the nonparametric estimation of the density function of an underlying random variable from a sequence of strongly mixing noisy observations. We develop a two-step estimation procedure to accomplish this task. At the first step, we propose an appropriate nonparametric kernel density estimation based on the observations, which allows a flexible bandwidth matrix. At the second step, we invoke an iterative algorithm to estimate the underlying density function, where the initialization function is constructed using the estimator established at the first step. Under some smoothness conditions on the involved densities, we show that the estimator resulting from the iterative procedure is a consistent estimator of the underlying density. This indicates that deconvolution can be achieved by correcting an appropriate kernel density estimator constructed on the basis of noisy observations. Our analysis is conducted in the real domain.
This paper focuses on investigating the problem of finding a common element of the set of solutions of a generalized nonlinear implicit variational-like inclusion problem involving an (A, eta)-maximal m-relaxed monoto...
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This paper focuses on investigating the problem of finding a common element of the set of solutions of a generalized nonlinear implicit variational-like inclusion problem involving an (A, eta)-maximal m-relaxed monotone mapping in the sense of L.-G.-s.i.p. and the set of fixed points of a total asymptotically nonexpansive mapping. To achieve such a purpose, a new iterative algorithm is constructed. Applying the concepts of graph convergence and generalized resolvent operator associated with an (A, eta)-maximal m-relaxed monotone mapping in the sense of L.-G.-s.i.p. As an application of the obtained equivalence relationship, the strong convergence of the sequence generated by our proposed iterative algorithm to a point belonging to the intersection of the two sets mentioned above is proved.
Panel data model with fixed effects is widely used in economic and administrative applications. However, the presence of factors: measurement errors, data variability and outliers may potentially decrease the accuracy...
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Panel data model with fixed effects is widely used in economic and administrative applications. However, the presence of factors: measurement errors, data variability and outliers may potentially decrease the accuracy of the model prediction. In this paper, we use panel interval-valued data to represent measurement errors and data volatility of observations. Further, we propose a corresponding panel interval-valued data model with fixed effects, in which both the response and explanatory variables are interval-valued data. To reduce the impact of outliers on our model, we propose a robust estimation method based on the iterative weighted least squares technique. Later, Monte Carlo simulation and empirical application demonstrate that our model is a suitable tool for analyzing the behaviour of panel interval-valued data.
To improve the estimation efficiency of high-dimensional regression problems, penalized regularization is routinely used. However, accurately estimating the model remains challenging, particularly in the presence of c...
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To improve the estimation efficiency of high-dimensional regression problems, penalized regularization is routinely used. However, accurately estimating the model remains challenging, particularly in the presence of correlated effects, wherein irrelevant covariates exhibit strong correlation with relevant ones. This situation, referred to as correlated data, poses additional complexities for model estimation. In this paper, we propose the elastic-net multi-step screening procedure (EnMSP), an iterative algorithm designed to recover sparse linear models in the context of correlated data. EnMSP uses a small repeated penalty strategy to identify truly relevant covariates in a few iterations. Specifically, in each iteration, EnMSP enhances the adaptive lasso method by adding a weighted l2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$l_2$$\end{document} penalty, which improves the selection of relevant covariates. The method is shown to select the true model and achieve the l2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$l_2$$\end{document}-norm error bound under certain conditions. The effectiveness of EnMSP is demonstrated through numerical comparisons and applications in financial data.
In this paper, we present a generalized Cayley operator and a generalized Cayley inclusion problem (GCIP). A fixed point formulation of (GCIP) is established and using this an iterative algorithm is developed to show ...
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In this paper, we present a generalized Cayley operator and a generalized Cayley inclusion problem (GCIP). A fixed point formulation of (GCIP) is established and using this an iterative algorithm is developed to show the existence and convergence of the solutions of (GCIP). We also establish the equivalence of the (GCIP) and generalized resolvent equation problem (GREP), and develop an iterative algorithm and some of its equivalent forms to approximate the solution of (GREP). To support our results, we construct a numerical example and convergence graphs using MATLAB programming.
The main goal of this manuscript is to investigate a fractional optimal control problem subject to a dynamical system involving Hadamard fractional derivatives. Necessary conditions for the optimality of the considere...
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The main goal of this manuscript is to investigate a fractional optimal control problem subject to a dynamical system involving Hadamard fractional derivatives. Necessary conditions for the optimality of the considered problem are derived in terms of the corresponding Euler-Lagrange equations. An iterative method is also proposed to numerically solve the obtained equations from the necessary optimality conditions. Two illustrative examples are considered and simulated in order to show the applicability and efficiency of the proposed method. Numerical simulations show that the used method presents some satisfying results regarding the absolute error values.
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