Search for: estimated-parameter
0.006 seconds

    Estimation of the order and parameters of a fractional order model from a noisy step response data

    , Article Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME ; Vol. 136, issue. 3 , May , 2014 ; ISSN: 00220434 Tavakoli-Kakhki, M ; Tavazoei, M. S ; Sharif University of Technology
    This paper deals with integral based methods to estimate the order and parameters of simple fractional order models from the extracted noisy step response data of a process. This data can be obtained from both open-loop and closed-loop tests. Numerical simulation results are presented to verify the robustness of these proposed methods in the presence of the measurement noise  

    Phase-I robust parameter estimation of simple linear profiles in multistage processes

    , Article Communications in Statistics: Simulation and Computation ; 2019 ; 03610918 (ISSN) Khedmati, M ; Akhavan Niaki, T ; Sharif University of Technology
    Taylor and Francis Inc  2019
    This paper addresses the problem of robust parameter estimation of simple linear profiles in multistage processes in the presence of outliers in Phase I. In this regard, two robust approaches, namely the Huber’s M-estimator and the MM estimator, are proposed to estimate the parameters of the process in Phase I in the presence of outliers in historical data. In addition, the U statistic is applied to the robust parameter estimates to remove the effect of the cascade property in multistage processes and as a result, to obtain adjusted robust estimates of the parameters of simple linear profiles. The performance of the proposed methods is evaluated under weak and strong autocorrelations... 

    Parameter and order estimation from noisy step response data

    , Article IFAC Proceedings Volumes (IFAC-PapersOnline) ; 2013 , Pages 492-497 ; 14746670 (ISSN) ; 9783902823274 (ISBN) Tavakoli Kakhki, M ; Tavazoei, M. S ; Mesbahi, A ; Sharif University of Technology
    In this paper, two integral based methods are proposed to estimate the order and the parameters of simple fractional order models from the noisy step response data. Numerical simulation results show the efficiency of the proposed methods in the presence of the measurement noise  

    Fast estimation of space-robots inertia parameters: A modular mathematical formulation

    , Article Acta Astronautica ; Volume 127 , 2016 , Pages 283-295 ; 00945765 (ISSN) Nabavi Chashmi, S. Y ; Malaek, S. M. B ; Sharif University of Technology
    Elsevier Ltd 
    This work aims to propose a new technique that considerably helps enhance time and precision needed to identify "Inertia Parameters (IPs)" of a typical Autonomous Space-Robot (ASR). Operations might include, capturing an unknown Target Space-Object (TSO), "active space-debris removal" or "automated in-orbit assemblies". In these operations generating precise successive commands are essential to the success of the mission. We show how a generalized, repeatable estimation-process could play an effective role to manage the operation. With the help of the well-known Force-Based approach, a new "modular formulation" has been developed to simultaneously identify IPs of an ASR while it captures a... 

    Estimating the parameters of weibull distribution using simulated annealing algorithm

    , Article Applied Mathematics and Computation ; Volume 183, Issue 1 , 2006 , Pages 85-93 ; 00963003 (ISSN) Abbasi, B ; Eshragh Jahromi, A. H ; Arkat, J ; Hosseinkouchack, M ; Sharif University of Technology
    Weibull distribution plays an important role in failure distribution modeling in reliability studies. It is a hard work to estimate the parameters of Weibull distribution. This distribution has three parameters, but for simplicity, a parameter is omitted and as a result, the estimation of the others will be easily done. When the three-parameter distribution is of interest, the estimation procedure will be quite boring. Maximum likelihood estimation is a good method, which is usually used to elaborate on the parameter estimation. The likelihood function formed for the parameter estimation of a three-parameter Weibull distribution is very hard to maximize. Many researchers have studied this... 

    An efficient parameter selection criterion for image denoising

    , Article 5th IEEE International Symposium on Signal Processing and Information Technology, Athens, 18 December 2005 through 21 December 2005 ; Volume 2005 , 2005 , Pages 872-877 Pirsiavash, H ; Kasaei, S ; Marvasti, F ; Sharif University of Technology
    The performance of most image denoising systems depends on some parameters which should be set carefully based on noise distribution and its variance. As in some applications noise characteristics are unknown, in this research, a criterion which its minimization leads to the best parameter set up is introduced. The proposed criterion is evaluated for the wavelet shrinkage image denoising algorithm using the cross validation procedure. The criterion is tested for some different values of thresholds, and the output leading to the minimum criterion value is selected as the final denoised output. The resulting outputs of our method and the previous threshold selection scheme for the wavelet... 

    Matrix-variate probabilistic model for canonical correlation analysis

    , Article Eurasip Journal on Advances in Signal Processing ; Volume 2011 , 2011 ; 16876172 (ISSN) Safayani, M ; Manzuri Shalmani, M. T ; Sharif University of Technology
    Motivated by the fact that in computer vision data samples are matrices, in this paper, we propose a matrix-variate probabilistic model for canonical correlation analysis (CCA). Unlike probabilistic CCA which converts the image samples into the vectors, our method uses the original image matrices for data representation. We show that the maximum likelihood parameter estimation of the model leads to the two-dimensional canonical correlation directions. This model helps for better understanding of two-dimensional Canonical Correlation Analysis (2DCCA), and for further extending the method into more complex probabilistic model. In addition, we show that two-dimensional Linear Discriminant... 

    Estimation of weibull parameters for wind energy application in Iran's cities

    , Article Wind and Structures, An International Journal ; Volume 21, Issue 2 , 2015 , Pages 203-221 ; 12266116 (ISSN) Sedghi, M ; Hannani, S. K ; Boroushaki, M ; Sharif University of Technology
    Techno Press  2015
    Wind speed is the most important parameter in the design and study of wind energy conversion systems. The weibull distribution is commonly used for wind energy analysis as it can represent the wind variations with an acceptable level of accuracy. In this study, the wind data for 11 cities in Iran have been analysed over a period of one year. The Goodness of fit test is used for testing data fit to weibull distribution. The results show that this data fit to weibull function very well. The scale and shape factors are two parameters of the weibull distribution that depend on the area under study. The kinds of numerical methods commonly used for estimating weibull parameters are reviewed. Their... 

    Energy allocation for parameter estimation in block CS-based distributed MIMO systems

    , Article 2015 International Conference on Sampling Theory and Applications, SampTA 2015, 25 May 2015 through 29 May 2015 ; May , 2015 , Pages 523-527 ; 9781467373531 (ISBN) Abtahi, A ; Modarres Hashemi, M ; Marvasti, F ; Tabataba, F. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Exploiting Compressive Sensing (CS) in MIMO radars, we can remove the need of the high rate A/D converters and send much less samples to the fusion center. In distributed MIMO radars, the received signal can be modeled as a block sparse signal in a basis. Thus, block CS methods can be used instead of classical CS ones to achieve more accurate target parameter estimation. In this paper a new method of energy allocation to the transmitters is proposed to improve the performance of the block CS-based distributed MIMO radars. This method is based on the minimization of an upper bound of the sensing matrix block-coherence. Simulation results show a significant increase in the accuracy of multiple... 

    Phenomenological contact model characterization and haptic simulation of an endoscopic sinus and skull base surgery virtual system

    , Article 4th RSI International Conference on Robotics and Mechatronics, ICRoM 2016, 26 October 2016 through 28 October 2016 ; 2017 , Pages 84-89 ; 9781509032228 (ISBN) Sadeghnejad, S ; Esfandiari, M ; Farahmand, F ; Vossoughi, G ; Sharif University of Technology
    During the endoscopic sinus and skull base training surgeries, the haptic perception of tool-tissue interaction and even transitions and ruptures in the tissues are fundamental which should be taken into account in a robotic control scheme. However, this problem is extremely complex given the nature and the variety of tissues involved in an ESS procedures. In this article, ex-vivo indentation and relaxation experiments associated with an offline model estimation of the interaction between tissues and a surgical tool are presented. The estimated parameters of the modified Kelvin-Voigt model are then used to provide a realistic tool-tissue interaction dynamic model. Finally, the principle of a... 

    A Physiological model-based study of flow-mediated dilation in peripheral arteries using finger photoplethysmogram signal

    , Article 2017 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Habib Parsafar, M ; Zahedi, E ; Vosoughi Vahdat, B ; Sharif University of Technology
    Flow-mediated dilation measurement in the brachial artery using ultrasound imaging (FMD-US) is a common noninvasive procedure for endothelial function evaluation in the peripheral arteries. As FMD-US is operator-dependent and involves onerous equipment, its use has been mostly confined to research settings. In this paper, we propose to use the more accessible finger photoplethysmogram signal in conjunction with the FMD test (FMD-PPG) as a surrogate method. To this end, a tube-load physiological model of the upper arterial path in the arm is developed. Signals acquired from young and elderly subjects (N=20) are then investigated using model parameter estimation by the genetic algorithm. Our... 

    Information hiding with optimal detector for highly correlated signals

    , Article 2009 IEEE International Conference on Communications, ICC 2009, Dresden, 14 June 2009 through 18 June 2009 ; 2009 ; 05361486 (ISSN); 9781424434350 (ISBN) Sahraeian, M. E ; Akhaee, M. A ; Marvasti, F ; Sharif University of Technology
    In this paper, a novel scaling based information hiding approach robust against noise and gain attack is presented. The host signal is assumed to be stationary Gaussian modeled with a first-order autoregressive process. For data embedding, the host signal is divided into two parts. One part is manipulated while the other part is kept unchanged for parameter estimation. The decoding scheme using the ratio of samples is suitable for highly correlated signals in which the decoding process is difficult. By calculating the distribution of the ratio, the performance of the maximum likelihood decoder is analytically studied. The proposed algorithm is applied to several artificial Gaussian... 

    A hybrid assimilation scheme for characterization of three-phase flow in porous media

    , Article Inverse Problems in Science and Engineering ; Volume 27, Issue 9 , 2019 , Pages 1195-1220 ; 17415977 (ISSN) Jahanbakhshi, S ; Pishvaie, M. R ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    In this study, ensemble Kalman filter (EnKF) is first applied to estimate absolute and relative permeabilities jointly under three-phase flow condition in the porous media. By assimilating historical data, absolute permeability field is adjusted progressively towards its reference. However, assimilation process does not improve the estimation of all relative permeability parameters, and some of them are poorly estimated at the end of assimilation. To improve the estimation of the relative permeability curves, we propose a new hybrid approach in which the estimation process of the absolute and relative permeabilities is separated. In this approach, gridblock permeabilities are again estimated... 

    Minimizing the uncertainties of seismological-geotechnical source parameters using a genetic algorithm approach

    , Article 9th International Conference on Computational Structures Technology, CST 2008, Athens, 2 September 2008 through 5 September 2008 ; Volume 88 , 2008 ; 17593433 (ISSN); 9781905088232 (ISBN) Nicknam, A ; Abbasnia, R ; Bozorgnasab, M ; Eslamian, Y ; Nicknam, A ; Sharif University of Technology
    Civil-Comp Press  2008
    The main purpose of this article is to estimate the seismological source parameters of the December 26, 2003, Bam earthquake Mw6.5 (Iran). The selected station is far away from the causative fault so that the synthesized ground motion would not be influenced by near source problems such as directivity effects. The well known Empirical Green's Functions (EGF) is used to synthesize the three components of main shock. The Kostrov slip model describing the entire rupture process was incorporated in the model. A generic algorithm (GA) technique is proposed for minimizing the differences between the synthesized time series and those of observed data. The estimated time series were validated by... 

    Use of PSO in parameter estimation of robot dynamics; part one: No need for parameterization

    , Article 2012 16th International Conference on System Theory, Control and Computing, ICSTCC 2012 - Joint Conference Proceedings ; 2012 ; 9786068348483 (ISBN) Jahandideh, H ; Namvar, M ; Sharif University of Technology
    Offline procedures for estimating parameters of robot dynamics are practically based on the parameterized inverse dynamic model. In this paper, we present a novel approach to parameter estimation of robot dynamics which removes the necessity of parameterization (i.e. finding the minimum number of parameters from which the dynamics can be calculated through a linear model with respect to these parameters). This offline approach is based on a simple and powerful swarm intelligence tool: the particle swarm optimization (PSO). In this paper, we discuss and validate the method through simulated experiments. In "Part Two" we analyze our method in terms of robustness and compare it to robust... 

    Estimating seismic demand parameters using the endurance time method

    , Article Journal of Zhejiang University: Science A ; Volume 12, Issue 8 , 2011 , Pages 616-626 ; 1673565X (ISSN) Madarshahian, R ; Estekanchi, H ; Mahvashmohammadi, A ; Sharif University of Technology
    The endurance time (ET) method is a time history based dynamic analysis in which structures are subjected to gradually intensifying excitations and their performances are judged based on their responses at various excitation levels. Using this method, the computational effort required for estimating probable seismic demand parameters can be reduced by an order of magnitude. Calculation of the maximum displacement or target displacement is a basic requirement for estimating performance based on structural design. The purpose of this paper is to compare the results of the nonlinear ET method with the nonlinear static pushover (NSP) method of FEMA 356 by evaluating performances and target... 

    A neural network applied to estimate Burr XII distribution parameters

    , Article Reliability Engineering and System Safety ; Volume 95, Issue 6 , June , 2010 , Pages 647-654 ; 09518320 (ISSN) Abbasi, B ; Hosseinifard, S. Z ; Coit, D. W ; Sharif University of Technology
    The Burr XII distribution can closely approximate many other well-known probability density functions such as the normal, gamma, lognormal, exponential distributions as well as Pearson type I, II, V, VII, IX, X, XII families of distributions. Considering a wide range of shape and scale parameters of the Burr XII distribution, it can have an important role in reliability modeling, risk analysis and process capability estimation. However, estimating parameters of the Burr XII distribution can be a complicated task and the use of conventional methods such as maximum likelihood estimation (MLE) and moment method (MM) is not straightforward. Some tables to estimate Burr XII parameters have been... 

    A multiscale phase field method for joint segmentation-rigid registration application to motion estimation of human knee joint

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 23, Issue 6 , 2011 , Pages 445-456 ; 10162372 (ISSN) Eslami, A ; Esfandiarpour, F ; Shakourirad, A ; Farahmand, F ; Sharif University of Technology
    Image based registration of rigid objects has been frequently addressed in the literature to obtain an object's motion parameters. In this paper, a new approach of joint segmentation-rigid registration, within the variational framework of the phase field approximation of the Mumford-Shah's functional, is proposed. The defined functional consists of two Mumford-Shah equations, extracting the discontinuity set of the reference and target images due to a rigid spatial transformation. Multiscale minimization of the proposed functional after finite element discretization provided a sub-pixel, robust algorithm for edge extraction as well as edge based rigid registration. The implementation...