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Total 26 records

    A new pseudolinear solution to bearing-only tracking

    , Article IEEE National Radar Conference - Proceedings ; 2013 ; 10975659 (ISSN) ; 9781467357920 (ISBN) Hejazi, F ; Khalili, M. M ; Norouzi, Y ; Nayebi, M. M ; Sharif University of Technology
    2013
    Abstract
    The main focus of this paper is on the estimation of target motion parameters using bearing measurements. Here, based on a linearization of measurements, a recursive least squares (RLS) solution is developed. The performance of the proposed method is compared to PLE which uses the same approach in measurement linearization. Simulation results show the excellence of the proposed method over the PLE, and RLS results are in vicinity of the CRLB  

    Indirect adaptive control of discrete chaotic systems

    , Article Chaos, Solitons and Fractals ; Volume 34, Issue 4 , 2007 , Pages 1188-1201 ; 09600779 (ISSN) Salarieh, H ; Shahrokhi, M ; Sharif University of Technology
    2007
    Abstract
    In this paper an indirect adaptive control algorithm is proposed to stabilize the fixed points of discrete chaotic systems. It is assumed that the functionality of the chaotic dynamics is known but the system parameters are unknown. This assumption is usually applicable to many chaotic systems, such as the Henon map, logistic and many other nonlinear maps. Using the recursive-least squares technique, the system parameters are identified and based on the feedback linearization method an adaptive controller is designed for stabilizing the fixed points, or unstable periodic orbits of the chaotic maps. The stability of the proposed scheme has been shown and the effectiveness of the control... 

    Adaptive modeling of laser powder deposition process for control and monitoring application

    , Article JVC/Journal of Vibration and Control ; Volume 13, Issue 5 , 2007 , Pages 461-473 ; 10775463 (ISSN) Durali, M ; Fathi, A ; Khajepour, A ; Toyserkani, E ; Sharif University of Technology
    2007
    Abstract
    The laser powder deposition (LPD) process is an advanced material processing technique with many applications. Despite this fact, reliable and accurate control schemes have not yet been fully developed for the process. In this paper, identification of the LPD process is examined to find a more accurate model to predict and control the height of clad in real time. The model is adaptive single inputsingle output (SISO) and its structure is very similar to the Hammerstein model when the effective power (a function of laser power and velocity) is selected as the input and the clad height as the output. Weighted extended recursive least square (WERLS) is adopted to simultaneously estimate the... 

    Introducing a distributed model of the heart

    , Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 419-424 ; 21551774 (ISSN) ; 9781457711992 (ISBN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    2012
    Abstract
    Conventional models of cardiovascular system (CV) frequently lack required detail. Once utilized to study the heart function, these models focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the CV system. It utilizes non-invasive blood flow and pressure seed data and temporal cardiac muscle regional activation to predict the operation of the heart. Proposed localized analysis considers specific regions of the heart, namely base, mid and apex sections of the left ventricle. This modular system is based on a hydraulic electric analogy model, estimating desired parameters, namely resistance (R), compliance (C),... 

    Ambient data-based online electromechanical mode estimation by error-feedback lattice RLS filter

    , Article IEEE Transactions on Power Systems ; 2017 ; 08858950 (ISSN) Setareh, M ; Parniani, M ; Aminifar, F ; Sharif University of Technology
    Abstract
    This paper proposes a novel error-feedback lattice recursive least-squares (EF-LRLS) filter for online estimation of power system oscillatory modes. The EF-LRLS filter is applied to ambient data provided by phasor measurement units to identify the autoregressive (AR) model parameters. This filter has a modular structure; accordingly, if the length of the filter equals N, it identifies AR(1) to AR(N) models concurrently. In the proposed method, removing very low and high frequencies and re-sampling steps are fulfilled in an online fashion. This adaptive filter has less computational complexity than standard RLS filter, making it an appropriate choice for online system identification. The... 

    Ambient data-based online electromechanical mode estimation by error-feedback lattice RLS filter

    , Article IEEE Transactions on Power Systems ; Volume 33, Issue 4 , July , 2018 , Pages 3745-3756 ; 08858950 (ISSN) Setareh, M ; Parniani, M ; Aminifar, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    This paper proposes a novel error-feedback lattice recursive least-squares (EF-LRLS) filter for online estimation of power system oscillatory modes. The EF-LRLS filter is applied to ambient data provided by phasor measurement units to identify the autoregressive (AR) model parameters. This filter has a modular structure; accordingly, if the length of the filter equals $N$, it identifies AR(1) to ${m{AR(}}N)$ models concurrently. In the proposed method, removing very low and high frequencies and resampling steps are fulfilled in an online fashion. This adaptive filter has less computational complexity than standard RLS filter, making it an appropriate choice for online system identification.... 

    Non-Stationary stabilized fast transversal RLS filter for online power system modal estimation

    , Article IEEE Transactions on Power Systems ; Volume 34, Issue 4 , 2019 , Pages 2744-2754 ; 08858950 (ISSN) Setareh, M ; Parniani, M ; Aminifar, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Online monitoring of inter-area oscillations is a vital need for secure operation of large-scale power systems. This paper aims at online estimation of inter-area modes by a novel stabilized fast transversal recursive least squares (SFTRLS) filter running on ambient power system data received from phasor measurement units. The SFTRLS filter is a fast finite-impulse response adaptive filter that is widely used in communication applications, such as noise and echo cancelation. It has the lowest computational complexity among least-squares filters and directly calculates coefficients of the parametric model selected for identifying a system under study. In the proposed method, the SFTRLS filter... 

    A novel distributed model of the heart under normal and congestive heart failure conditions

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 227, Issue 4 , 2013 , Pages 362-372 ; 09544119 (ISSN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    2013
    Abstract
    Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison... 

    A Recursive Least Squares Solution to Bearing-only Tracking

    , M.Sc. Thesis Sharif University of Technology Hejazi Kookamari, Farzam (Author) ; Nayebi, Mohammd Mahdi (Supervisor)
    Abstract
    The conventional bearing-only tracking solutions are based on Kalman filter. Whenever the problem equations are nonlinear, Extended Kalman Filter (EKF) or more complicated methods are used necessarily. However, EKF suffers of being biased and unstable. Here a new recursive method based on a linear modeling of the problem is proposed, the method does not need an initial guess and outperforms the Kalman filter in the terms of accuracy, complexity and stability. Furthermore, input information needed for the proposed tracking filter is just the observer position, time and value of each angle measurements and the computation load is less than even a simple EKF. mathematical analysis, as well as... 

    Design of a fault Tolerated Intelligent Control System for a Nuclear Reactor Power Control

    , M.Sc. Thesis Sharif University of Technology Hatami, Ehsan (Author) ; Vosoughi, Naser (Supervisor) ; Salarieh, Hassan (Supervisor)
    Abstract
    Many advanced process plants and machines are extremely complex, and always depend on automatic control for satisfactory operation. In order to achieve and maintain system stability and assure satisfactory and safe operation, there is increasing demand for dynamic systems to continue acceptable operation following failures. Therefore failures detection has always been an important aspect of fault tolerant control design. In nuclear power plant, for example, tens of alarms can occur in a few second after a fault. Fault detection might be of utmost importance due to safety, political and other reasons. There are many methods to detect fault on the system. In this project approach based on... 

    A hybrid method of modified cat swarm optimization and gradient descent algorithm for training anfis

    , Article International Journal of Computational Intelligence and Applications ; Volume 12, Issue 2 , June , 2013 ; 14690268 (ISSN) Orouskhani, M ; Mansouri, M ; Orouskhani, Y ; Teshnehlab, M ; Sharif University of Technology
    2013
    Abstract
    This paper introduces a novel approach for tuning the parameters of the adaptive network-based fuzzy inference system (ANFIS). In the commonly used training methods, the antecedent and consequent parameters of ANFIS are trained by gradient-based algorithms and recursive least square method, respectively. In this study, a new swarm-based meta-heuristic optimization algorithm, so-called "Cat Swarm Optimization", is used in order to train the antecedent part parameters and gradient descent algorithm is applied for training the consequent part parameters. Experimental results for prediction of Mackey-Glass model and identification of two nonlinear dynamic systems reveal that the performance of... 

    A low-latency QRD-RLS architecture for high-throughput adaptive applications

    , Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 63, Issue 7 , 2016 , Pages 708-712 ; 15497747 (ISSN) Alizadeh, M. S ; Bagherzadeh, J ; Sharifkhani, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    Abstract
    A novel architecture for QR decomposition-based recursive least squares is presented. It offers low latency for applications where the channel equalization and adaptive filtering are mandatory. This approach reduces the computations by rewriting the equations in a manner that lets intense hardware resource sharing by reusing similar values in different computations. Moreover, precision range conversion allows for combining complex operations such as root square and division with minimum effect on the overall quantization error. Hence, an efficient lookup table-based solution has highly enhanced the performance of the design by 2.7 times with respect to the previous works  

    Parameter identification of a parametrically excited rate micro-gyroscope using recursive least squares method

    , Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1889-1900 ; 10263098 (ISSN) Mohammadi, Z ; Salarieh, H ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    Estimation of physical parameters of a parametrically excited gyroscope is studied in this paper. This estimation is possible by reading the input and output data of the gyroscope. Because of different faults in the manufacturing process and tolerances, physical parameters of a gyroscope are not exactly same as the expected values of the manufacturer. Moreover, changing of temperature, humidity, external acceleration, etc. can change the physical parameters of the gyro. Thus, the physical parameters of gyroscope are not fixed values and may deviate from the desired designed values. The physical parameters of gyroscope determine the optimal region for working of gyroscope. Thus, if the... 

    New method for assessing the utility harmonic impedance based on fuzzy logic

    , Article IET Generation, Transmission and Distribution ; Volume 11, Issue 10 , 2017 , Pages 2448-2456 ; 17518687 (ISSN) Zebardast, A ; Mokhtari, H ; Sharif University of Technology
    Abstract
    This study proposes a novel non-invasive method for estimating the utility harmonic impedance. Since the major concern about non-invasive methods is the dependency of the accuracy of the results on background harmonic fluctuations, proper measured samples are selected using a three-point data selection technique to increase the method accuracy. Then, a new non-invasive method for the evaluation of the utility harmonic impedance at a point of common coupling (PCC) based on fuzzy logic is presented. In the proposed method, fuzzy logic is applied to the constrained recursive least squares algorithm (CRLS) by designing a set of fuzzy if-then rules. Due to the changes in the quantities at a... 

    Damping Critical Electromechanical Oscillations in Power System Through Remedial Actions Using Wide Area Measurement System (WAMS)

    , Ph.D. Dissertation Sharif University of Technology Setareh, Mohammad (Author) ; Parniani, Mostafa (Supervisor) ; Aminifar, Farrokh (Co-Supervisor)
    Abstract
    Nowadays, by proliferation the basis of the phasor-based synchronous wide area measurement system (WAMS), its application for improving electromechanical oscillations damping has been considered by researchers. In interconnected power systems, inter-area modes are usually critical modes. There are two approaches for damping these modes by utilizing WAMS: 1) the traditional approach of using power system stabilizers with wide area signals; and 2) discrete corrective actions by changing the operating conditions. The first approach requires a thorough study at the design stage, installation and testing. Besides, the controller is designed for a specific operating point. Nevertheless, in the... 

    Nonlinear Analysis and Design of Estimation and Filtering System for a MEMS Gyroscope with Parametric Excitation

    , M.Sc. Thesis Sharif University of Technology Fazlyab, Mahyar (Author) ; Salarieh, Hassan (Supervisor) ; Alasti, Aria (Co-Advisor)
    Abstract
    Recently, parametric excitation has been proposed and experimentally proven to provide micro gyroscopes with robustness to parameter variations and enhancement of sensitivity [L.A. Oropeza-Ramos, C.B. Burgner, K.L. Turner, Robust micro-rate sensor actuated by parametric resonance, Sensors and Actuators A: Physical, 152 (2009) 80-87].The first part of this thesis aims at investigating the nonlinear dynamics of MEMS vibratory gyroscopes with parametric excitation which can be represented by a minor variation of nonlinear Mathieu equation coupled to a Duffing oscillator. Our approach is based on analytical frequency response derivation via method of multiple time scales. Stability of responses,... 

    Packet Loss Replacement in VOIP Using Linear Prediction Method

    , M.Sc. Thesis Sharif University of Technology Miralavi, Reza (Author) ; Ghorshi, Mohammad Ali (Supervisor) ; Mortazavi, Mohammad (Supervisor)
    Abstract
    In real-time packet-based communication systems one major problem is misrouted or delayed packets which result in degraded perceived voice quality. If some speech packets are not available on time, the packet is known as lost packet. The easiest task of a network terminal receiver is to replace silence for the duration of lost speech segments. In a high quality communication system in order to avoid quality reduction due to packet loss a suitable method and/or algorithm is needed to replace the missing segments of speech.There are several methods which have been proposed to reduce the effect of packet loss such as Waveform Substitution, High Order Autoregressive, Linear Prediction (LP),... 

    Identification of Mass Properties of a Leo Satellite

    , M.Sc. Thesis Sharif University of Technology Amini, Mohammad Ali (Author) ; Alasti, Aria (Supervisor)
    Abstract
    Algorithms for online identification of parameters of a satellite’s moment of inertia tensor based on two methods (recursive least squares and Kalman Filter) is presented and compared with each other. It is assumed that the satellite actuators are three orthogonal reaction wheels. The only available sensor is a 3-axis rate gyro, which measures the angular velocity of satellite in body coordinate system. For validation of algorithms on earth, a similar identifier was designed for a satellite simulator. Due to difference in Dynamics of satellite and satellite simulator, capability of identifying center of gravity was added to algorithms. In order to account for friction in air bearing of... 

    Structural Health Monitoring using Bayesian Optimization of the finite element model of structures and Kalman filter

    , M.Sc. Thesis Sharif University of Technology Sadegh, Alireza (Author) ; Bakhshi, Ali (Supervisor)
    Abstract
    With confidence in the recorded observations, the RLS method no longer estimates the recorded measurements by sensors, i.e. the displacement and speed of the floors, and only estimates the parameters. In contrast, in the EKF method, in addition to estimating the structure's parameters, a more precise estimation of the observations recorded by the sensors has been done by accepting the noise in the recorded observations. These methods, which are based on the Bayesian updating, investigate the two primary sources of uncertainty in a problem: a) measurement noise or observation noise, and b) process noise, which includes modeling errors. In these methodologies, the unknown system parameters,... 

    Adaptive handover algorithm in heterogeneous femtocellular networks based on received signal strength and signal-to-interference-plus-noise ratio prediction

    , Article IET Communications ; Volume 8, Issue 17 , 27 November , 2014 , Pages 3061-3071 ; ISSN: 17518628 Kalbkhani, H ; Yousefi, S ; Shayesteh, M. G ; Sharif University of Technology
    Abstract
    In this study, an efficient handover algorithm based on the received signal strength (RSS) prediction is presented for two-tier macro-femtocell networks in which, because of the fading effects of channel and short coverage range of femtocells, ping-pong handovers may take place. In the proposed approach, first each mobile station (MS) uses the recursive least square algorithm for predicting the RSS from the candidate base stations (BSs) including both femtocell and macrocell BSs. Then, according to the predicted RSS values, several future values of signal-to-interference plus noise ratio (SINR) are calculated. Afterwards, the candidate list of BSs is pruned according to the estimated future...