共查询到20条相似文献,搜索用时 15 毫秒
1.
We have developed an efficient algorithm for transposing large matrices in place. The algorithm is efficient because data are accessed either sequentially in blocks or randomly within blocks small enough to fit in cache, and because the same indexing calculations are shared among identical procedures operating on independent subsets of the data. This inherent parallelism makes the method well suited for a multiprocessor computing environment. The algorithm is easy to implement because the same two procedures are applied to the data in various groupings to carry out the complete transpose operation. Using only a single processor, we have demonstrated nearly an order of magnitude increase in speed over the previously published algorithm by Gate and Twigg (1977) for transposing a large rectangular matrix in place. With multiple processors operating in parallel, the processing speed increases almost linearly with the number of processors. A simplified version of the algorithm for square matrices is presented as well as an extension for matrices large enough to require virtual memory. 相似文献
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A fast algorithm is presented for a two-dimensional transform of a data matrix such as Fourier or Hadamard transforms. It can be applied to a matrix, which is too large for the main storage and is stored sequentially rowwise in an auxiliary storage. The size of the matrix may be of Rmrows and of arbitrary number of columns. Whenever R rows of working area are available in the main storage, the matrix is read out, processed, and stored back m times. This new algorithm does not require the presently used method of transposing the data matrix. 相似文献
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In this paper, dielectric resonators possessing separable-coordinate geometries immersed in planarly-inhomogeneous media are analyzed using a volume electric-field integral-equation (IE)/Galerkin's technique. A three-dimensional complete entire-domain basis function set is utilized in numerically solving the IE. It is shown that a few terms of one physically significant subset of basis functions are usually sufficient for the accurate determination of complex resonant frequencies of cylindrical and rectangular resonators immersed in homogeneous and planarly inhomogeneous environments. The results using a few basis functions show good agreement with the previous literature, and new results are presented for some rectangular resonator geometries 相似文献
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The processing of hexagonally sampled two-dimensional signals 总被引:3,自引:0,他引:3
Two-dimensional signals are normally processed as rectangularly sampled arrays; i.e., they are periodically sampled in each of two orthogonal independent variables. Another form of periodic sampling, hexagonal sampling, offers substantial savings in machine storage and arithmetic computations for many signal processing operations. In this paper, methods for the processing of two-dimensional signals which have been sampled as two-dimensional hexagonal arrays are presented. Included are methods for signal representation, linear system implementation, frequency response calculation, DFT calculation, filter design, and filter implementation. These algorithms bear strong resemblances to the corresponding results for rectangular arrays; however, there are also many important differences. Some comparisons between the two methods for representing planar data will also be presented. 相似文献
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Dr. Jian Li Petre Stoica Dunmin Zheng 《Multidimensional Systems and Signal Processing》1996,7(2):151-178
This paper presents a computationally efficient eigenstructure-based 2D-MODE algorithm for two-dimensional frequency estimation. We derive the theoretical performance of the 2D-MODE estimator and show that it is asymptotically statistically efficient under either the assumption that the number of temporal snapshots is large or the signal-to-noise ratio is high. Numerical examples showing the performance of this algorithm and comparing it with the computationally efficient subspace rotation algorithms are also given. We show that the statistical performance of the 2D-MODE algorithm is better than that of the subspace rotation methods. The amount of computations required by the former is no more than a few times of that needed by the latter for either small numbers of spatial measurements or a single temporal snapshot, which are the cases of interest herein. 相似文献
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An efficient code-timing estimator for DS-CDMA signals 总被引:5,自引:0,他引:5
Dunmin Zheng Jian Li Miller S.L. Strom E.G. 《Signal Processing, IEEE Transactions on》1997,45(1):82-89
We present an efficient algorithm for estimating the code timing of a known training sequence in an asynchronous direct-sequence code division multiple access (DS-CDMA) system. The algorithm is a large sample maximum likelihood (LSML) estimator that is derived by modeling the known training sequence as the desired signal and all other signals including the interfering signals and thermal noise as unknown colored Gaussian noise that is uncorrelated with the desired signal. The LSML estimator is shown to be robust against the near-far problem and is also compared with several other code timing estimators via numerical examples. It is found that the LSML approach can offer noticeable performance improvement, especially when the loading of the system is heavy 相似文献
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Werner D.H. Werner P.L. Huffman J.A. Ferraro A.J. Breakall J.K. 《Antennas and Propagation, IEEE Transactions on》1993,41(12):1716-1719
The generalized exponential integral is one of the most fundamental integrals in antenna theory and for many years exact solutions to this integral have been sought. This paper considers an exact solution to the generalized exponential integral which is completely general and independent of the usual restrictions involving the wavelength, field point distance and dipole length is considered. The exact series representation presented converges rapidly in the induction and near-field regions of the antenna, and therefore provides an alternative to numerical integration. Two method of moments formulations are considered. They use the exact expression for the generalized exponential integral in the computation of the impedance matrix elements. It is demonstrated that, for very thin straight-wire antennas, an asymptotic expansion can be used to obtain a numerically convenient form of the generalized exponential integral 相似文献
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This paper derives a Karhunen-Loeve (K-L) expansion of the time-varying output of a multipath Rayleigh fading wide-sense-stationary uncorrelated-scattering (WSSUS) channel. It is shown that under the same mean-squared error condition, the number of terms required by the truncated K-L expansion is less than that of the series expansion obtained by using the discrete-path approximation of the channel so that simulation using the K-L expansion is more efficient. This computational advantage becomes more significant as higher simulation accuracy is required. The derived K-L expansion is applied to develop an efficient simulation technique for digital transmission over a multipath Rayleigh fading WSSUS channel using an optimum receiver. We show that the proposed technique requires shorter computation time than two other known simulation techniques 相似文献
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This paper presents our unified approach to the solution of large system analysis problems. The macromodular behavioral technique combines multiple-logic function macromodeling, functional latency and nested macromodel. We take advantage of the dynamic behavior and the repetitive modular structure of a system to improve the computational efficiency during system analysis. Several Bipolar and MOSFET electronic networks are used to demonstrate the merits of the macromodular behavioral method for large system analysis.Parts of the paper have been presented at the 16th Design Automation Conference (1979) and at the 1980 IEEE International Symposium on Circuits and Systems. 相似文献
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Predrag B. Petrovi? 《Signal, Image and Video Processing》2012,6(1):109-123
The paper presents a reconstruction of analogue multi-harmonic signals, from a number of integrated values of input signals. Based on the value of the integral of the original input signal, with a known frequency spectrum but unknown amplitudes and phases, a reconstruction of its basic parameters is done by the means of derived analytical and summarized expressions. It is applied to signal reconstruction, spectral estimation, system identification, as well as in other important signal processing problems. The proposed method of processing can be used for precise RMS measurements (or power and energy) of periodic signal based on the presented signal reconstruction. Subsequent calculation of all relevant indicators related to the monitoring and processing of ac voltage and current signals is provided in this manner. The paper investigates the errors related to the signal parameter estimation, and there is a computer simulation that demonstrates the accuracy of these algorithms. 相似文献
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For a given or estimated noise type, the determination of optimal L-filter coefficients is computationally intensive and extremely time consuming. Thus, even though the L-filters obtained are very successful in restoring signals corrupted by non-Gaussian noise, their on-line design in real-time applications is not practical. In this paper, a new methodology for the design of L-filters is presented in which the L-filter coefficients are obtained by approximating the covariance matrix of the ordered samples through the use of Taylor expansion. The paper also presents several examples that compare the proposed approach to the classical approach. The simulations show the value of the proposed approach. 相似文献
15.
Ngai-Fong Law Wan-Chi Siu 《Signal Processing, IEEE Transactions on》2002,50(11):2806-2819
We have studied the computational complexity associated with the overcomplete wavelet transform for the commonly used spline wavelet family. By deriving general expressions for the computational complexity using the conventional filtering implementation, we show that the inverse transform is significantly more costly in computation than the forward transform. To reduce this computational complexity, we propose a new spatial implementation based on the exploitation of the correlation between the lowpass and the bandpass outputs that is inherent in the overcomplete representation. Both theoretical studies and experimental findings show that the proposed spatial implementation can greatly simplify the computations associated with the inverse transform. In particular, the complexity of the inverse transform using the proposed implementation can be reduced to slightly less than that of the forward transform using the conventional filtering implementation. We also demonstrate that the proposed scheme allows the use of an arbitrary boundary extension method while maintaining the ease of the inverse transform. 相似文献
16.
De Bernardinis F. Roncella R. Saletti R. Terreni P. Bertini G. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1999,7(1):105-110
This paper presents a new architecture for the hardware implementation of additive synthesis for high-quality musical sound generation. A marginally stable second-order infinite-impulse-response filter is used to generate each sinusoid, the frequency, amplitude, and phase of which can independently be specified. A chip has been designed with a bit-level systolic array approach. It is capable of performing 1200 sinusoid real-time synthesis. Furthermore, it is possible to connect up to 11 chips, to achieve an outstanding 13 200 sinusoid synthesis. Two completely independent output channels are available as 20-b streams. The system is clocked at 60 MHz when working with a 44.1-kHz sampling rate. The integrated circuit is designed in a 0.5-μm CMOS technology and has a core area of approximately 19 mm2 相似文献
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An efficient CMOS buffer for driving large capacitive loads 总被引:1,自引:0,他引:1
《Solid-State Circuits, IEEE Journal of》1986,21(3):464-469
A CMOS class AB high-drive buffer suitable for driving large capacitive and moderate resistive loads is presented. The buffer, designed using 3-/spl mu/m technology, occupies only 100 mils/SUP 2/ of area and dissipates 1.5 mW of DC power from a /spl plusmn/2.5-V supply, yet it is capable of driving a 5000-pF capacitor at over 100-kHz clocking frequency. The buffer achieves good slew rate and fast settling by entering into a high-drive state during slewing and returning to a low-power wide-band state during the settling period. Unconditional stability is attained when C/SUB L//spl ges/100 pF and R/SUB L//spl ges/10 k/spl Omega/. Total harmonic distortion is below 0.5% for over 70% of the full supply range. 相似文献