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51.
This paper considers the estimation problem for a trigonometric regression model with the noise specified by the Ornstein–Uhlenbeck
process with unknown parameter. We propose a sequential procedure which ensures a prescribed mean square precision uniformly
in the nuisance parameter. The asymptotic behaviour of the procedure duration mean has been studied.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
52.
《Surface and interface analysis : SIA》2004,36(1):61-70
In spectroscopy, the recorded spectra can often be modelled as the noisy convolution product of an instrumental function with the ‘true’ signal to be estimated. Such models have often been used for high‐resolution electron energy‐loss spectroscopy (HREELS). In this article, a new method is suggested to estimate the ‘true’ HREELS signal, i.e. the original electronic diffusion function with ‘true’ peak intensities. Our method relies upon the use of wavelets that, because they exhibit simultaneous time and frequency localization, are well‐suited for signal analysis. Firstly, a wavelet shrinkage algorithm is used to filter the noise. This is achieved by decomposing the noisy signal into an appropriate wavelet basis and then thresholding the wavelet coefficients that contain noise. This algorithm has a particular threshold related to frequency and time. Secondly, the broadening due to the instrumental response is eliminated through a deconvolution process. This step mainly rests on the existing relation between the Lipschitz regularity of the signal and the decay with scale of its wavelet coefficients and on least squares. The efficiency of this technique is highlighted by comparing the results obtained with those provided by other published methods. This work is the second in a series of three papers in this issue. The first one presents background knowledge on the wavelets required to understand the estimation methods. The third paper explores the application of wavelet filtering and deconvolution techniques to x‐ray photoelectron spectroscopy. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
53.
The noise of hybrid soliton pulse source (HSPS) with linearly chirped Gaussian apodized fiber Bragg grating is analyzed by couple-mode equations including spontaneous emission noise when the HSPS is mode-locked. Relative intensity noise is calculated using numerical solutions of these equations. It is shown that transform limited pulses are generated over a wide tuning range around the fundamental mode-locking frequency with low spontaneous noise. However, a high noise level affects the operation of device, and therefore transform-limited pulses are not obtainable over a wide tuning range. It is also shown that noise is extremely sensitive to the RF and DC currents, linewidth enhancement factor, gain saturation parameter and spontaneous coupling factor. 相似文献
54.
55.
调制不稳定性对级联放大光纤传输系统信噪比的影响 总被引:1,自引:0,他引:1
在考虑光纤损耗和级联放大器的情况下,推导了调制不稳定性的产生条件和增益的普适解析表达式,分析了调制不稳定性对信噪比的影响,给出了一个新的计算信噪比的表达式。 相似文献
56.
添加剂在氧化铈抛光中的作用机理的探索 总被引:2,自引:0,他引:2
本文在试验基础上,对添加剂在氧化铈抛光中作用机理—提高氧化铈抛光效率的机理和防止玻璃抛光表面腐蚀的机理作了探索,指出在一定的抛光工艺条件下,每一种添加剂对于一定品位的氧化铈和一定牌号的光学玻璃有一最佳的加入量。 相似文献
57.
记X为复数域上无限维Banach空间,H为无限维复可分Hilert空间。本文给出B(X)上保持点谱的满射可加射具有的形式,以及B(H)上某些初等算子保点谱的充要条件。 相似文献
58.
N. V. Sotskaya O. V. Dolgikh E. I. Ryabinina 《Russian Journal of Electrochemistry》2005,41(8):866-873
The rate of anodic oxidation of the hypophosphite ion on alloys Ni-P, Ni-B, and Ni-Mo-P is studied as a function of their composition and structure. The organic compounds that are customarily used to stabilize electrolytes of electroless nickel plating are shown to come useful when controlling composition of the Ni-P coatings at the expense of their different influence on the rates of partial processes of deposition of the alloy components. The formation of catalytic activity of such coatings is affected mostly by a structural factor. With alloys Ni-P, Ni-B, and Ni-Mo-P, whose composition was varied by altering the concentration of the source of the alloying component, dependence of catalytic activity of the surface on the composition is defined mainly by an electronic factor.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 972–980.Original Russian Text Copyright © 2005 by Sotskaya, Dolgikh, Ryabinina. 相似文献
59.
In this paper we report some of the important results of experimental investigations of the flicker noise near the metal-insulator
(MI) transition in doped silicon single crystals. This is the first comprehensive work to study low-frequency noise in heavily
doped Si over an extensive temperature range (2 K<T<500 K). The measurements of conductance fluctuations (flicker noise) were carried out in the frequency range 10−2<f<4 × 101 Hz in single crystalline Si across the MI transition by doping with phosphorous and boron. The magnitude of noise in heavily
doped Si is much larger than that seen in lightly doped Si over the whole temperature range. The extensive temperature range
covered allowed us to detect two distinct noise mechanisms. At low temperatures (T<100 K) universal conductance fluctuations (UCF) dominate and the spectral dependence of the noise is determined by dephasing
the electron from defects with two-levels (TLS). At higher temperatures (T>200 K) the noise arises from activated defect dynamics. As the MI transition is approached, the 1/f spectral power, typical of the metallic regime, gets modified by the presence of discrete Lorentzians which arise from generation-recombination
process which is the characteristic of a semiconductor. 相似文献
60.
We examine asymptotically periodic density evolution in one-dimensional maps perturbed by noise, associating the macroscopic state of these dynamical systems with a phase space density. For asymptotically periodic systems density evolution becomes periodic in time, as do some macroscopic properties calculated from them. The general formalism of asymptotic periodicity is examined and used to calculate time correlations along trajectories of these maps as well as their limiting conditional entropy. The time correlation is shown to naturally decouple into periodic and stochastic components. Finally, asymptotic periodicity is studied in a noise-perturbed piecewise linear map, focusing on how the variation of noise amplitude can cause a transition from asymptotic periodicity to asymptotic stability in the density evolution of this system. 相似文献