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VARIATIONAL IMAGE DENOISING WHILE CONSTRAINING THE distribution OF THE RESIDUAL

ELECTRONIC TRANSACTIONS ON NUMERICAL ANALYSIS 2014年 42卷 64-84页

作者： Lanza, Alessandro Morigi, Serena Sgallari, Fiorella Yezzi, Anthony J. Univ Bologna Dept Math CIRAM Bologna Italy Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA

We present a denoising method aimed at restoring images corrupted by additive noise based on the assumption that the distribution of the noise process is known. The proposed variational model uses Total Variation (TV) regularization (chosen simply for its popularity;any other regularizer could be substituted as well) but constrains the distribution of the residual to fit a given target noise distribution. The residual distribution constraint constitutes the key novelty behind our approach. The restored image is efficiently computed by the constrained minimization of an energy functional using an Alternating Directions Methods of Multipliers (ADMM) procedure. Numerical examples show that the novel residual constraint indeed improves the quality of the image restorations.

关键词： image denoising variational models image residual probability distribution function

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New analytical expressions for the performance metrics of wireless communication system over Weibull/Lognormal composite fading

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2017年 82卷 397-405页

作者： Chauhan, Puspraj Singh Tiwari, Diwaker Soni, Sanjay Kumar GB Pant Engn Coll Dept Elect & Commun Ghurdauri 246194 Uttarakhand India

A realistic propagation scenario is more frequently characterized by a composite multipath/shadowed fading. In this work, a class of Weibull/Lognormal (W-LN) composite fading channel has been analysed and investigated. New analytical approximations to various important performance metrics of wireless communication systems such as the average symbol error probability (SEP), the outage probability, the amount of fading (AF), and the channel capacity are derived. Further, an asymptotic analysis of the composite fading channel is carried out and closed form expressions of the average SEP with and without maximal ratio combining (MRC) diversity along with the coding and diversity gain are presented. The solutions are presented in terms of Fox H-function and are valid for both the integer and non-integer values of the multipath and shadowing parameters. The results are validated via Monte-Carlo simulations and exact numerical results.

关键词： Channel fading probability distribution function Average symbol error probability Channel capacity Micro-diversity

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distribution network expansion planning and DG placement in the presence of uncertainties

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2015年第Dec.期73卷 665-673页

作者： Hemmati, Reza Hooshmand, Rahmat-Allah Taheri, Nabi Kermanshah Univ Technol Dept Elect Engn Kermanshah Iran Univ Isfahan Dept Elect Engn Esfahan Iran

distribution network expansion planning (DNEP) is one of the most important tools to deal with the demand growth in a system. DNEP is usually carried out through reinforcement or installation of new components. In this paper, a new and combined methodology is used to consider several practical aspects in DNEP such as uncertainty, distributed generation (DG), load growth, electricity market and multi stage dynamic expansion are included in the planning. So that DNEP is addressed in the presence of distributed generation (DG), considering load and price uncertainties under electricity market environment. The proposed planning aims at minimizing investment and operational costs simultaneously. Since DNEP in coordination with DG planning leads to reduce planning cost;therefore, the coordinated DNEP and DG planning are presented in this paper. The proposed planning is implemented by the particle swarm optimization (PSO) technique. Besides, the uncertainties are modeled as the probability distribution function (PDF) and Monte-Carlo simulation (MCS) is used to insert the uncertainties into the programming. The proposed planning is carried out based on the 9-bus as well as Kianpars-Ahvaz test systems (Kianpars-Ahvaz is a practical network in Ahvaz province, Iran). The simulation results demonstrate the ability and effectiveness of the proposed planning to deal with uncertainties under electricity market environment. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： distribution network expansion planning Distributed generation Monte-Carlo simulation Particle swarm optimization probability distribution function Uncertainty

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Change point detection in GARCH models for voice activity detection

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IEEE TRANSACTIONS ON AUDIO SPEECH AND LANGUAGE PROCESSING 2008年第5期16卷 1038-1046页

作者： Tahmasbi, Rasool Rezaei, Sadegh Shahid Chamran Univ Ahvaz Dept Stat Ahvaz *** Iran

This paper presents a robust algorithm for voice activity detection (VAD) based on change point detection in a generalized autoregressive conditional heteroscedasticity (LARCH) process. LARCH models are new statistical methods that are used especially in economic time series and are a popular choice to model speech signals and their changing variances. Change point detection is also important in economic sciences. In this paper, no distinct probability functions are assumed for speech and noise distributions. Also, to detect speech/nonspeech intervals, no likelihood ratio test (LRT) is employed. For testing parameter constancy in LARCH models, the algorithm of the Cramer-von Mises (CVM) test is described. This test is a nonparametric test and is based on the empirical quantiles. We show that VAD is related to the parameter constancy test in LARCH process, and we illustrate several examples.

关键词： change point detection empirical quantiles Gaussian process generalized autoregressive conditional heteroscedasticity (GARCH) process probability distribution function random field voice activity detection (VAD)

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A spectroscopic investigation of turbulence in magnetized plasmas

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COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION 2003年第3-4期8卷 469-475页

作者： Marandet, Y. Capes, H. Godbert-Mouret, L. Guirlet, R. Koubiti, M. Stamm, R. Univ Aix Marseille 1 PIIM Ctr St Jerome F-13397 Marseille France DRFC CEA F-13108 St Paul Les Durance France

We present a spectroscopic investigation of turbulence in the Tore-Supra edge plasma, where deuterium spectral lines are found to exhibit a power-law behavior in their wings. Such a feature is not predicted by the equilibrium line broadening theory in the conditions of the edge plasma, where the thermal Stark effect is negligible. Therefore, the possible role of turbulence is investigated along two separate paths. Indeed, both the Stark and the Doppler profiles may differ significantly from the equilibrium profiles. (C) 2003 Elsevier B.V. All rights reserved.

关键词： Spectroscopy Line wings Plasma turbulence probability distribution function Levy flights

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Uncertainty analysis of planar and spatial robots with joint clearances

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MECHANISM AND MACHINE THEORY 2000年第9期35卷 1239-1256页

作者： Zhu, JM Ting, KL Tennessee Technol Univ Mfg Ctr Cookeville TN 38505 USA

Joint clearance in mechanisms and robots leads to uncertainty in function deviation. Unlike the effect of the link tolerance on the performance quality, the uncertainty effect of the joint clearance to the performance can not be eliminated by calibration because of the random nature. In this paper, based on the probability theory, a general probability density function (p.d.f.) of the endpoint of planar robots is established. The p.d.f. of the endpoint of a planer robot is equivalent to that of endpoint of a string of planar joint deviation vectors. By grouping the planar joint deviation vectors and establishing the structural constraint conditions between the vector groups, a basic approach of deriving the general p.d.f. of spatial robots is also presented. Based on the general p.d.f. of the endpoint, the distribution functions of the robot endpoint for any position tolerance zone and any joint distribution type, can be derived. The method is demonstrated by using some common types of position tolerance zones with uniform as well as normal distribution for joint clearance. The distribution functions of the robot endpoint are calculated and tabulated. These distribution functions and tables provide a convenient way to obtain the probability value for a robot to position its end point within a desired tolerance zone, and to determine the joint clearance value for the desired type of tolerance zone and the prescribed probability value of position repeatability. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

关键词： robot joint clearance uncertainty tolerance probability density function probability distribution function

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Interacting multiple model particle filter for prognostics of lithium-ion batteries

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MICROELECTRONICS RELIABILITY 2017年 70卷 59-69页

作者： Su, Xiaohong Wang, Shuai Pecht, Michael Zhao, Lingling Ye, Zhe Harbin Inst Technol Sch Comp Sci & Technol Harbin 150001 Peoples R China Univ Maryland CALCE College Pk MD 20742 USA

We propose a new data-driven prognostic method based on the interacting multiple model particle filter (IMMPF) for determining the remaining useful life (RUL) of lithium-ion (Li-ion) batteries and the probability distribution function (PDF) of the associated uncertainty. The method applies the IMMPF to different state equations. Modeling the battery capacity degradation is very important for predicting the RUL of Li-ion batteries. In this study, improvements are made on various Li-ion battery capacity models (i.e., polynomial, exponential, and Verhulst models). Further, three different one-step state transition equations are developed, and the IMMPF method is applied to estimate the RUL of Li-ion batteries with the use of the three improved models. The PDF of the predicted RUL is obtained by combining the PDFs obtained with each individual model. We conduct four case studies to validate the proposed method. The results are as follows: (1) the three improved models require fewer parameters than the original models, (2) the proposed prognostic method shows stable and high prediction accuracy, and (3) the proposed method narrows the uncertainty PDF of the predicted RUL of Li-ion batteries. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Lithium-ion batteries Remaining useful life Particle filter Interacting multiple model particle filter probability distribution function

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Evaluating the suitability of wind speed probability distribution models: A case of study of east and southeast parts of Iran

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ENERGY CONVERSION AND MANAGEMENT 2016年 119卷 101-108页

作者： Alavi, Omid Mohammadi, Kasra Mostafaeipour, Ali KN Toosi Univ Technol Dept Elect Engn Tehran Iran Univ Massachusetts Dept Mech & Ind Engn Amherst MA 01003 USA Yazd Univ Dept Ind Engn Yazd Iran

Precise information of wind speed probability distribution is truly significant for many wind energy applications. The objective of this study is to evaluate the suitability of different probability functions for estimating wind speed distribution at five stations, distributed in the east and southeast of Iran. Nakagami distribution function is utilized for the first time to estimate the distribution of wind speed. The performance of Nakagami function is compared with seven typically used distribution functions. The achieved results reveal that the more effective function is not similar among all stations. Wind speed characteristics, quantity and quality of the recorded wind speed data can be considered as influential parameters on the performance of the distribution functions. Also, the skewness of the recorded wind speed data may have influence on the accuracy of the Nakagami distribution. For Chabahar and Khaf stations the Nakagami distribution shows the highest performance while for Lutak, Rafsanjan and Zabol stations the Gamma, Generalized Extreme Value and Inverse-Gaussian distributions offer the best fits, respectively. Based on the analysis, the Nakagami distribution can generally be considered as an effective distribution since it provides the best fits in 2 stations and ranks 3rd to 5th in the remaining stations;however, due to the close performance of the Nakagami and Weibull distributions and also flexibility of the Weibull function as its widely proven feature, more assessments on the performance of the Nakagami distribution are required. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Wind speed probability distribution function Nakagami distribution Statistical analysis Maximum likelihood estimator

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Audio analysis of statistically instantaneous signals with mixed Gaussian probability distributions

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INTERNATIONAL JOURNAL OF ELECTRONICS 2012年第10期99卷 1333-1350页

作者： Naik, Ganesh R. Wang, Wenwu RMIT Univ Melbourne Vic 3001 Australia Univ Surrey Ctr Vis Speech & Signal Proc Guildford GU2 5XH Surrey England

In this article, a novel method is proposed to measure the separation qualities of statistically instantaneous audio signals with mixed Gaussian probability distributions. This study evaluates the impact of the probability distribution function (PDF) of the mixed signals on the outcomes of both sub- and super-Gaussian distributions. Different Gaussian measures are evaluated by using various spectral-distortion measures. It aims to compare the different audio mixtures from both super-Gaussian and sub-Gaussian perspectives. Extensive computer simulation confirms that the separated sources always have super-Gaussian characteristics irrespective of the PDF of the signals or mixtures. The result based on the objective measures demonstrates the effectiveness of source separation in improving the quality of the separated audio sources.

关键词： blind source separation probability distribution function independent component analysis kurtosis signal to interference ratio sub-Gaussian super-Gaussian

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A comparative analysis of wind speed probability distributions for wind power assessment of four sites

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TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES 2016年第6期24卷 4724-4735页

作者： Sohoni, Vaishali Gupta, Shivcharan Nema, Rajeshkumar Maulana Azad Natl Inst Technol Dept Elect Engn Bhopal India

In this paper, five probability distribution functions are employed to fit the wind speed data from four different geographical locations in the world in a preliminary analysis. These wind regimes are selected such that they represent wide ranges of mean wind speeds and present different shapes of wind speed histograms. The wind speed data used for modelling consist of 10-min average SCADA data from three US wind farms and hourly averages recorded at a weather station in Canada. Out of the five, three functions, namely Weibull, Rayleigh, and gamma, which provide a better fit to the data, are selected to carry out further analyses. This study investigates the ability of these functions to match different statistical descriptions of wind regimes. Parameter estimation is done by the method of moments, and models are evaluated by root mean square error and R square methods. The suitability of PDFs to predict the wind power densities and annual energy production using manufacturers' power curve data at three of the selected sites is analysed. Power curves extracted from actual data of one wind farm using novel four- and five-parameter logistic approximations are also introduced here for energy analyses.

关键词： Wind speed distribution probability distribution function method of moments wind power density

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