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A simple method for pulse repetition interval estimation and tracking radar pulse trains with complex pulse repetition interval modulations
, Article Advanced Science Letters ; Volume 19, Issue 8 , 2013 , Pages 2262-2265 ; 19366612 (ISSN) ; Keshavarzi, M ; Amiri, K ; Sharif University of Technology
2013
Abstract
In an electronic warfare environment, an electronic support system receives signals emitted by different radars. One of the key tasks in an electronic support system is PRI estimation tracking Pulse Trains using Pulse Repetition Interval (PRI) of these signals. In this paper we present a simple method for PRI estimation and tracking radar pulse trains with complex PRI Modulations. This method uses nonlinear least square, Pisarenko and innovative methods for PRI estimation and tracking pulse train. Simulation results show high robustness of the proposed method against noise (spurious and missing pulses)
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) ; 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...
Proposing a Control Method for Malaria
, M.Sc. Thesis Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor)
Abstract
In every year malaria has enormous fatality around the world, so this disease has to be controlled. In this thesis based on a model given in the literature[12], a model predictive controller has been designed and its performance has been compared with that of the optimal control. The simulation results show that in the case of model mismatch, the performance of model predictive control is superior. In model selection, it has been tried that a comprehensive model that has enough inputs for control to be selected. A linear time varying model is used to simulate the nonlinear behavior of the nonlinear system. The Least Squares method is used to update the model parameters
An accurate FIR approximation of ideal fractional delay filter with complex coefficients in Hilbert space
, Article Journal of Circuits, Systems and Computers ; Volume 14, Issue 3 , 2005 , Pages 497-505 ; 02181266 (ISSN) ; Nabavi, A ; Hessabi, Sh ; Sharif University of Technology
2005
Abstract
This paper presents a low-order and accurate method for the design of FIR fractional delay (FD) filters with complex coefficients. This method employs least square technique in Hilbert space to approximate the ideal FD transfer function with a FIR filter and to calculate its coefficients. The main advantages of the resulting filter are: very good response at all frequencies compared to other FD filter design methods and a good method to create very small delay. Design examples are presented to illustrate the effectiveness of this new design approach. © World Scientific Publishing Company
Face recognition under varying illumination based on histogram equalized processed images
, Article ISPA 2011 - 7th International Symposium on Image and Signal Processing and Analysis ; 2011 , Pages 349-354 ; 9789531841597 (ISBN) ; Jamzad, M ; European Association for Signal Processing (EURASIP); IEEE Signal Processing Society; IEEE Region 8; IEEE Croatia Section; IEEE Croatia Section Signal Processing Chapter ; Sharif University of Technology
Abstract
This paper proposes an enhanced illumination compensation algorithm, which can compensate for the uneven illuminations on human faces and reconstruct face images in normal lighting conditions. To detect the illumination category, based on 65 categories in YaleB database, the images processed using Block-based Histogram Equalization (BHE) is compared with the original face image processed using histogram equalization (HE). Based on the identified illumination category, a quadratic model is used to reconstruct an image that will visually be under normal illumination. In order to avoid the effect of light source intensity on face images, we used HE method. Experimental results show that, by...
Adaptive characterisation of a human hand model during intercations with a telemanipulation system
, Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 688-693 ; 9781467372343 (ISBN) ; Sadeghnejad, S ; Farahmand, F ; Vosoughi, G ; Sharif University of Technology
2015
Abstract
Proper modeling of the human arm dynamic, as it interacts with telemanipulation and haptic systems, is important in enhancing the transparency of these systems. In this article, we introduced an adaptive identifier to estimate the impedance characteristic of a human operator as it interacts with a single translational degree of freedom mechanism. The five parameter model, including an extra spring and damper for a better approximation of the dynamic behavior of human arm, has been used. Since the impedance characteristic of human arm differs from one individual to another, it is important to estimate these parameters for each individual and update the controller to enhance the transparency...
A novel method for fault location of transmission lines by wide-area voltage measurements considering measurement errors
, Article IEEE Transactions on Smart Grid ; Volume 6, Issue 2 , 2015 , Pages 874-884 ; 19493053 (ISSN) ; Ranjbar, A. M ; Sharif University of Technology
Abstract
Smart transmission grids are intended to utilize various measurements for enhanced operation. In particular, synchronized phasor measurements have found many applications in this context. This paper presents a linear weighted least-squares (WLS) method for fault location estimation of transmission lines by synchronized voltage measurements. The measurements may be taken from the faulted line terminals or buses far from the faulted line. The circuit equations of the network are used to find the transfer function between the fault location and each voltage measurement. Next, two auxiliary variables are defined to transform the nonlinear fault location estimation problem into a linear WLS...
Constructing a Robust Least Squares Support Vector Machine Based on Lp-norm and L∞-norm
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezamoddin (Supervisor)
Abstract
In the last decades, Support Vector Machine (SVM) has been used for supervised classification due to its wide applications. In addition, SVM is a mathematical programming tool, that as other optimization-based approaches, turns to be useful for a successful development of supervised classification. Based on current research in the literature, we explain the extension of a developed method for SVM using L2-norm to the more general case of Lp-norms with p > 1. The Kernel function is used frequently in the L2-SVM model, but the multidimensional Kernel is used as a general function in Lp-SVM. Finally, we use Lp-LSSVM model, with 0
Effect of Amplitude of Electric Field on the Rotation of Liquid Film
, M.Sc. Thesis Sharif University of Technology ; Amjadi, Ahmad (Supervisor)
Abstract
By direct and alternating electric field applied to thin film of liquid suspended in the air we can spin out and control it. Rotation pattern depends on the geometry of the electrodes and the applied magnetic field. This is called a rotating liquid film (Liquid Film Motor). To determine the cause of rotation, different models have been proposed. In this project we have tried to check the accuracy of any of the models. Using particle velocimetry using the photo, we calculate the velocity pattern. Then, using the Navier-Stokes equation calculate the acceleration and viscosity from the velocity. Then, for a special arrangement using a finite diffrent method, electric potential and the electric...
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) ; 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...
An alternating minimization method for sparse channel estimation
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 27 September 2010 through 30 September 2010, St. Malo ; Volume 6365 LNCS , 2010 , Pages 319-327 ; 03029743 (ISSN) ; 364215994X (ISBN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2010
Abstract
The problem of estimating a sparse channel, i.e. a channel with a few non-zero taps, appears in many fields of communication including acoustic underwater or wireless transmissions. In this paper, we have developed an algorithm based on Iterative Alternating Minimization technique which iteratively detects the location and the value of the channel taps. In fact, at each iteration we use an approximate Maximum A posteriori Probability (MAP) scheme for detection of the taps, while a least square method is used for estimating the values of the taps at each iteration. For approximate MAP detection, we have proposed three different methods leading to three variants for our algorithm. Finally, we...
A method to calculate the linear load pay back factors for air conditioners
, Article Asia-Pacific Power and Energy Engineering Conference, APPEEC ; 2012 ; 21574839 (ISSN) ; 9781457705472 (ISBN) ; Kazemi, A ; Fotuhi Firuzabad, M ; Parvania, M ; Sharif University of Technology
Abstract
Load pay back effect is the excess of load as a result of load curtailment, observed in direct load control programs related to thermostatically controlled appliances. In this paper, according to a stochastic difference equation, the load profile of an aggregation of customers without control will be attained. Then the assumption to consider load pay back as linear will be examined through simulations. Afterwards, based on a data structure gained from performing load curtailments at each interval, least-square method will be used to fit load pay back factors for each interval. It is notable that there are some significant differences between the results attained in this paper and what was...
Model predictive control of blood sugar in patients with type-1 diabetes
, Article Optimal Control Applications and Methods ; Volume 37, Issue 4 , 2016 , Pages 559-573 ; 01432087 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
John Wiley and Sons Ltd
Abstract
In this article, two adaptive model predictive controllers (AMPC) are applied to regulate the blood glucose in type 1 diabetic patients. The first controller is constructed based on a linear model, while the second one is designed by using a nonlinear Hammerstein model. The adaptive version of these control schemes is considered to make them more robust against model mismatches and external disturbances. The least squares method with forgetting factor is used to update the model parameters. For simulation study, two well-known mathematical models namely, Puckett and Hovorka which describe the dynamical behavior of patient's body have been selected. The performances and robustness of the...
Fabrication, characterization, and error mitigation of non-flat sun sensor
, Article Sensors and Actuators, A: Physical ; Volume 261 , 2017 , Pages 243-251 ; 09244247 (ISSN) ; Durali, M ; Rashidian, B ; Jalali, M. A ; Sharif University of Technology
Abstract
We report the design, fabrication and error analysis of a sun sensor array composed of six photodiodes. The sensor estimates the direction of the sun using a linear least squares method. The performance of the sensor is deteriorated by three major sources: fabrication errors, scattered environmental light, and inexact modeling of photodiodes. Using a calibration procedure and modeling the uniform component of the environmental light, we mitigate the first two errors and significantly reduce root mean squared error from 2.63° to 0.83°. For a Field of View (FOV) of 110°, the maximum estimation error also drops from 3.8° to 1.6°. Through exact mathematical modeling of photodiodes, we...
Modeling convective heat propagation in a fractured domain with x-fem and least square method
, Article ASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017, 3 November 2017 through 9 November 2017 ; Volume 8 , 2017 ; 9780791858431 (ISBN) ; Khoei, A. R ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2017
Abstract
The main goal of the current study is developing an advanced and robust numerical tool for accurate capturing heat front propagation. In some applications such as impermeable medium, Heat transfer in the surrounding domain of fracture acts just as a conduction process but the heat transfer through the fractures appears as a convection process. From a mathematical point of view, a parabolic partial differential equation (PDE) should be solved in the surrounding domain whereas a hyperbolic PDE should be solved in the domain of fractures. In fact, they have completely different treatments and this is one of the complicated problems in this area. In this paper, the presence of fractures and...
Structural damage detection using principal component analysis of frequency response function data
, Article Structural Control and Health Monitoring ; Volume 27, Issue 7 , 2020 ; Nabiyan, M. S ; Rahimzadeh Rofooei, F ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
In this paper, a new sensitivity-based model updating method is presented based on the changes of principal components (PCs) of frequency response function (FRF). Structural damage estimation, identification of damage location and severity, is conducted by an innovative sensitivity relation. The sensitivity relation is derived by incorporating PC analysis (PCA) data obtained from the incomplete measured structural responses in a mathematical formulation and is then solved by the least square method. In order to demonstrate the performance of the proposed method, it is applied to a truss and a frame model. The results prove the ability of the method as a robust damage detection algorithm in...
Investigation of atmosphere thickness on EAS events by an array of particle detectors and CORSIKA simulations
, Article 30th International Cosmic Ray Conference, ICRC 2007, Merida, Yucatan, 3 July 2007 through 11 July 2007 ; Volume 4, Issue HE PART 1 , 2007 , Pages 15-18 ; Bahmanabadi, M ; Samimi, J ; Shadkam, A. H ; Sheydaei, F ; Anvari, A ; Sharif University of Technology
Universidad Nacional Autonoma de Mexico
2007
Abstract
The atmosphere effect before shower maximum is dominantly: an environment for development of Extensive Air Shower(EAS) events, but after that, the absorbtion effect of the atmosphere will be dominant. The shower maximum for about 100 TeV is near 500 gr/cm2 (∼5200m a.s.l), and most of EAS arrays in this energy range are at heights below the shower maximum height, specially for higher zenith angle EAS events, so we need to more concentration on the absorbtion effect specially in this energy range and our site. Therefore for this investigation we logged 476,675 true EAS events by an array of particle water Cherenkov detectors. We calculated the local coordinates (θ, φ) of each EAS event by...
B-Jump: Roller length, sequent depth, and relative energy loss using artificial neural networks
, Article Journal of Hydraulic Research ; Volume 45, Issue 4 , 2007 , Pages 529-537 ; 00221686 (ISSN) ; Bateni, S. M ; Fazeli, M ; Sharif University of Technology
International Association of Hydraulic Engineering Research
2007
Abstract
The phenomenon of the hydraulic jump is so complex that despite considerable laboratory and prototype studies, estimation of its main characteristics in a generalized and accurate form is still difficult. The Artificial Neural Network (ANN) approach aims at limiting the needs for costly and time-consuming experiments. In this study, two ANN models, multi-layer perceptron using back propagation algorithm (MLP/BP) and radial basis function using orthogonal least-squares algorithm (RBF/OLS), were used to predict the roller length, sequent depth, and the relative energy loss of the B-jump. Based on a pre-specified range of jump parameters, the input vectors include: upstream bed slope (tan θ),...
Controlling the chaos using fuzzy estimation of OGY and Pyragas controllers
, Article Chaos, Solitons and Fractals ; Volume 26, Issue 2 , 2005 , Pages 379-392 ; 09600779 (ISSN) ; Salarieh, H ; Sharif University of Technology
Elsevier Ltd
2005
Abstract
This paper illustrates the control of chaos using a fuzzy estimating system based on batch training and recursive least square methods for a continuous time dynamic system. The fuzzy estimator system is trained on both Ott-Geobogi-Yorke (OGY) control algorithm and Pyragas's delayed feedback control algorithm. The system, considered as a case study, is a Bonhoeffer-van der Pol (BVP) oscillator. It is found that the implemented fuzzy control system constructed on OGY algorithm results in smaller control transient response than that of the OGY control algorithm itself. The transient response of Pyragas fuzzy control does not show a significant improvement in compare to the Pyragas control...
State of charge estimation for lithium-ion batteries based on square root sigma point Kalman filter considering temperature variations
, Article IET Electrical Systems in Transportation ; Volume 12, Issue 3 , 2022 , Pages 165-180 ; 20429738 (ISSN) ; Jafari Gavzan, I ; Saidi, M. H ; Ahmadi, N ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The battery management system (BMS) in electric vehicles monitors the state of charge (SOC) and state of health (SOH) of lithium-ion battery by controlling transient parameters such as voltage, current, and temperature prevents the battery from operating outside the optimal operating range. The main feature of the battery management system is the correct estimation of the SOC in the broad range of vehicle navigation. In this paper, to estimate real-time of SOC in lithium-ion batteries and overcome faults of Extended Kalman Filter (EKF), the Square-Root Sigma Point Kalman Filter is applied on the basis of numerical approximations rather than analytical methods of EKF. For this purpose, the...