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991.
Since electronic switching systems usually require very strict reliability requirements as well as good performance objectives, we need to jointly analyse the performance and reliability of switching systems. In this paper, we compare conventional time–space–time switches with single space switches with those with multiple separated space switches, from the viewpoints of reliability and performance. We consider time–space–time switching networks which consist of N incoming time switches, i.e. one NxN space switch, two (N/2)x(N/2) space switches, and four (N/4)x(N/4) space switches. We introduce a Markov reliability model to study the effect of failures and analyse the reliability and performance of three different types of switching networks in terms of average blocking probability and the mean time to unreliable operation, as we vary the offered traffic. As a result, T–S–T switching networks with multiple separated space switches exhibit better performance and reliability than those with single space switches. 相似文献
992.
On the performance advantage of multitaper spectral analysis 总被引:3,自引:0,他引:3
The performance advantage of multitaper spectral analysis is quantified relative to weighted overlapped segment averaging (WOSA). To make the comparison of these two nonparametric spectral estimators, theoretical performance measures are derived in terms of leakage, variance, and resolution. The methods are then compared by evaluating each measure in turn, while requiring the other two measures to be equal. The results show that multitaper analysis always performs better than WOSA. For example, given the same leakage and resolution, multitaper analysis can have three-quarters to one-half the variance of WOSA. Given the same resolution and variance, multitaper analysis can exhibit a 10-20-dB leakage advantage over WOSA. These and other results provide compelling evidence for greater use of multitaper analysis in situations for which a nonparametric spectral estimator is appropriate 相似文献
993.
Translated from Izmeritel'naya Tekhnika, No. 7, pp. 8–9, July, 1992. 相似文献
994.
995.
The authors provide a convergence analysis for the Kohonen learning algorithm (KLA) with respect to vector quantizer (VQ) optimality criteria and introduce a stochastic relaxation technique which produces the global minimum but is computationally expensive. By incorporating the principles of the stochastic approach into the KLA, a deterministic VQ design algorithm, the soft competition scheme (SCS), is introduced. Experimental results are presented where the SCS consistently provided better codebooks than the generalized Lloyd algorithm (GLA), even when the same computation time was used for both algorithms. The SCS may therefore prove to be a valuable alternative to the GLA for VQ design 相似文献
996.
The use of the analytically decoupled near-tip displacement solutions as an alternative approach, is presented in this paper for the efficient finite element evaluation of the decoupled weight functions for an orthotropic 2-D crack. This alternative approach has been validated by directly comparing the prior weight function results with a symmetric mesh approach in the crack-tip neighborhood, and indirectly by comparing the calculated stress intensity factors (KI(II)) values using the computed weight functions with available KI(II) solutions of the 2-D mixed mode orthotropic cracks. In addition, this approach with analytically decoupled near-tip displacement solutions for calculating weight functions at all locations, can facilitate further extension of weight function evaluations to a more general 2-D anisotropic crack. 相似文献
997.
998.
M. D. Kannan Sa. K. Narayandass C. Balasubramanian D. Mangalaraj 《Journal of Materials Science》1992,27(18):5040-5044
Aluminium-neodymium oxide-aluminium thin film capacitors have been prepared by thermal evaporation and the d.c. conduction properties of these films have been studied. The thicknesses of the films have been determined by a multiple beam interferometer. The current-voltage power-law dependence showed that the conduction in these films is space-charge limited. The linear dependence of the current density on the square root of the applied field confirmed the exponential trap distribution. The trap density has been found to be of the order of 1026 m–3. It has also been observed that the Schottky type of conduction is predominant in the high-field region and the height of the Schottky barrier has been determined. It is seen that the conduction mechanism is an activated process with the activation energy decreasing with increasing field. 相似文献
999.
This paper proposes a parallel optimization approach to power system decomposition for voltage control. In this paper, a parallel simulated annealing (PSA) technique is developed to decompose power systems so that subsystems are equally separated in terms of the number of nodes and control variables. System decomposition is one of difficult discrete number combinatorial problems. The PSA technique provides better solutions than the conventional SA because of searching a solution near a global minimum over a wide range. The proposed method is tested in IEEE 30, 57, and 118 node systems 相似文献
1000.
Prediction error method for second-order blind identification 总被引:7,自引:0,他引:7
Blind channel identification methods based on the oversampled channel output are a problem of current theoretical and practical interest. In this paper, we introduce a second-order blind identification technique based on a linear prediction approach. In contrast to eigenstructure-based methods, it will be shown that the linear prediction error method is “robust” to order overdetermination. An asymptotic performance analysis of the proposed estimation method is carried out, consistency and asymptotic normality of the estimates is established. A closed-form expression for the asymptotic covariance of the estimates is given. Numerical simulations and investigations are finally presented to demonstrate the potential and the “robustness” of the proposed method 相似文献