Most iterative techniques for solving the symmetric positive-definite systemAx=b involve approximating the matrixA by another symmetric positive-definite matrixM and then solving a system of the formMz=d at each itera...
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Most iterative techniques for solving the symmetric positive-definite systemAx=b involve approximating the matrixA by another symmetric positive-definite matrixM and then solving a system of the formMz=d at each iteration. On a vector machine such as the CDC-STAR-100, the solution of this new system can be very time consuming. If, however, an approximationM−1 can be given toA−1, the solutionz=M−1d can be computed rapidly by matrix multiplication, a fast operation on the STAR. Approximations using the Neumann expansion of the inverse ofA give reasonable forms forM−1 and are presented. Computational results using the conjugate gradient method for the “5-point” matrixA are given.
In this paper, we introduce and discuss a new system of generalized nonlinear mixed quasivariational inclusions with -monotone operators in Hilbert spaces, which includes several systems of variational inequalities an...
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In this paper, we introduce and discuss a new system of generalized nonlinear mixed quasivariational inclusions with -monotone operators in Hilbert spaces, which includes several systems of variational inequalities and variational inclusions as special cases. By employing the resolvent operator technique associated with -monotone operators, we suggest two iterative algorithms for computing the approximate solutions of the system of generalized nonlinear mixed quasivariational inclusions. Under certain conditions, we obtain the existence of solutions for the system of generalized nonlinear mixed quasivariational inclusions and prove the convergence of the iterative sequences generated by the iterative algorithms. The results presented in this paper extend, improve and unify many known results in recent literature.
This paper investigates an iterative algorithm to control weighting coefficients of transmit/receive spatial filters in a frequency-division duplex (FDD) based eigen-mode space division multiplexing (E-SDM/FDD) system...
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ISBN:
(纸本)9781479958320
This paper investigates an iterative algorithm to control weighting coefficients of transmit/receive spatial filters in a frequency-division duplex (FDD) based eigen-mode space division multiplexing (E-SDM/FDD) system. In this system, weighting matrices of transmit/receive spatial filters are optimized using an iterative algorithm that minimizes the mean square error (MSE) of the virtual received signal, where the receiver feeds back relative channel characteristic information of the forward-link to the transmitter. This paper also presents an alternative feedback control method for optimizing the weighting coefficients of the transmit spatial filter in presence of feedback bit errors;the receiver determines the weighting coefficients at the transmitter and sends back relative information of them to the transmitter. This method will be able to mitigate the performance degradation caused by the feedback bit error. Simulation results of bit error rate (BER) performance proves the effectiveness of the proposed algorithm in the E-SDM/FDD 4 x 2 MIMO systems.
This paper proposes a new iterative fuzzy clustering (IFC) algorithm to impute missing values of datasets. The information provided by fuzzy clustering is used to update the imputed values through iterations. The perf...
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ISBN:
(纸本)9781509060344
This paper proposes a new iterative fuzzy clustering (IFC) algorithm to impute missing values of datasets. The information provided by fuzzy clustering is used to update the imputed values through iterations. The performance of the IFC algorithm is examined by conducting experiments on three commonly used datasets and a case study on a city mobility database. Experimental results show that the IFC algorithm not only works well for datasets with a small number of missing values but also provides an effective imputation result for datasets where the proportion of missing data is high.
The subaperture stitching interferometry is a technique suitable for testing high numerical-aperture optics, large-diameter spherical lenses and aspheric optics. In the stitching process, each subaperture has to be pl...
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ISBN:
(纸本)9781628417418
The subaperture stitching interferometry is a technique suitable for testing high numerical-aperture optics, large-diameter spherical lenses and aspheric optics. In the stitching process, each subaperture has to be placed at its correct position in a global coordinate, and the positioning precision would affect the accuracy of stitching result. However, the mechanical limitations in the alignment process as well as vibrations during the measurement would induce inevitable subaperture position uncertainties. In our previous study, a rotational scanning subaperture stitching interferometer has been constructed. This paper provides an iterative algorithm to correct the subaperture position without altering the interferometer configuration. Each subaperture is first placed at its geometric position estimated according to the F number of reference lens, the measurement zenithal angle and the number of pixels along the width of subaperture. By using the concept of differentiation, a shift compensator along the radial direction of the global coordinate is added into the stitching algorithm. The algorithm includes two kinds of compensators: one for the geometric null with four compensators of piston, two directional tilts and defocus, and the other for the position correction with the shift compensator. These compensators are computed iteratively to minimize the phase differences in the overlapped regions of subapertures in a least-squares sense. The simulation results demonstrate that the proposed method works to the position accuracy of 0.001 pixels for both the single-ring and multiple-ring configurations. Experimental verifications with the single-ring and multiple-ring data also show the effectiveness of the algorithm.
The conventional iterative Foruier transform algorithm proposed by Fienup which reconstruct the phase from the modulus is improved. Stagnation from which the conventional algorithm often suffers doses not occur in the...
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ISBN:
(纸本)081944121X
The conventional iterative Foruier transform algorithm proposed by Fienup which reconstruct the phase from the modulus is improved. Stagnation from which the conventional algorithm often suffers doses not occur in the improved algorithm.
This paper proposes a method for solving the monostatic radar cross section of the target with the iterative solution of the method of moments. In this method, the randomized algorithm is adapted to enhance the comput...
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ISBN:
(纸本)9780996007894
This paper proposes a method for solving the monostatic radar cross section of the target with the iterative solution of the method of moments. In this method, the randomized algorithm is adapted to enhance the computational efficiency of the matrix solution step by compressing the impedance matrix and the excitation matrix. The results of calculation examples show that the method is efficient and reliable.
In orthogonal frequency-division multiplex access (OFDMA) uplink, it is admitted that the carrier-frequency offsets (CFOs) between multi-transmitter and receiver introduce intercarrier interference (ICI) and cause sev...
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ISBN:
(纸本)0780391527
In orthogonal frequency-division multiplex access (OFDMA) uplink, it is admitted that the carrier-frequency offsets (CFOs) between multi-transmitter and receiver introduce intercarrier interference (ICI) and cause severe performance loss. In this paper, with reference to a detailed analysis of the ICI caused by CFOs, we propose a novel low-complexity iterative ICI cancellation algorithm, which is based on the perfect estimation of each user's CFO. Moreover, the convergence behaviors of the iterations are studied with three theorems, and the user-interleaving patterns suitable for this algorithm are presented. In accordance with the simulation results, we come to the conclusion that the low-complexity iterative algorithm can effectively suppress and cancel the ICI due to CFOs.
Two explicit iterative algorithms are developed in this paper for solving continuous coupled Lyapunov matrix equations. By introducing a tunable parameter, the considered matrix equations are transformed into the Kalm...
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ISBN:
(纸本)9781538629185
Two explicit iterative algorithms are developed in this paper for solving continuous coupled Lyapunov matrix equations. By introducing a tunable parameter, the considered matrix equations are transformed into the Kalman-Yakubovich matrix equations. Further, based on the obtained equations, an explicit iterative algorithm is constructed to solve the coupled Lyapunov matrix equations. In addition, by using the latest estimation an improved iterative algorithm is proposed. Some convergence results are obtained for the presented improved iterative algorithm. It is shown that the convergence performance of the proposed algorithms can be significantly improved if the tunable parameter can be properly chosen. Finally, a numerical example is given to show the merit of the presented algorithms.
Crosstalk is the major limiting issue in VDSL2 system. Based on matrix splitting and iterative theory, a general form of iterative crosstalk cancellation algorithm is first proposed for VDSL2 upstream transmission. Fr...
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ISBN:
(纸本)9781424448562
Crosstalk is the major limiting issue in VDSL2 system. Based on matrix splitting and iterative theory, a general form of iterative crosstalk cancellation algorithm is first proposed for VDSL2 upstream transmission. From using diagonal dominant and column wise diagonal dominant of crosstalk channel matrix property, two special iterative algorithms are then derived. Computer simulation results based on measured data verify that the iterative crosstalk cancellation algorithms can improve the performance and approach zero-forcing algorithm by successive iterations.
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