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    Adaptive synchronization of two different uncertain chaotic systems with unknown dead-zone input nonlinearities

    , Article JVC/Journal of Vibration and Control ; Volume 26, Issue 21-22 , 2020 , Pages 1956-1968 Heidarzadeh, S ; Shahmoradi, S ; Shahrokhi, M ; Sharif University of Technology
    SAGE Publications Inc  2020
    Abstract
    The present work addresses chaos synchronization between two different general chaotic systems with parametric and structural uncertainties, subject to external disturbances and input dead-zone nonlinearities. In this regard, a novel robust controller has been designed that guarantees asymptotic stability of synchronization errors and boundedness of all closed-loop signals. One advantage of the proposed controller over the existing control algorithms is using only one update law for estimating the structural uncertainties, external disturbances, and unknown characteristics of the dead-zone nonlinearities, which reduces the computational burden considerably. The designed controller is... 

    Behavior study of high impact resistant reinforced concrete frames using crack conduction method

    , Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Heidarzadeh, N ; Razavi, S. M ; Shamsaei, N ; Sharif University of Technology
    American Society of Mechanical Engineers  2006
    Abstract
    In this study, the influence of crack conduction method on behavior of reinforced concrete (RC) frame under iterative high impact loading were experimented. To investigate the structural behavior through large deformations and progressive damage and to identify the failure modes, the falling weight and falling height were set more than the structural strength in elastic state. A comprehensive scheme which indicated influence of location of initial cracks on behavior and failure mode of structure was developed. Falling weight impact test was conducted on twenty-one laboratory scaled RC frames which were categorized in four series regard to considered scheme. Concrete volume and compressive... 

    Using Learning Algorithms for Energy Efficient Routing in Wireless Sensor Network

    , M.Sc. Thesis Sharif University of Technology Heidarzadeh, Elahe (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Wireless Sensor Networks (WSNs) have attracted much attention in recent years for their unique characteristics and wide use in many different applications. WSNs are composed of many tiny sensor nodes that have limitations on energy level, bandwidth, processing power and memory. Therefore, reducing energy consumption and the increased network lifetime and scalability are the main routing challenges in sensor networks. Many algorithms were presented for routing in sensor networks; a class of theses algorithms is hierarchical algorithms based on clustering. Their main goals are to reduce energy consumption, distribution energy consumption in the whole network and increasing scalability. There... 

    Manufacturing and Optimization Of Full Composite Nose Of The Caled Jas 39 Fighter Using Genetic Algorithm

    , M.Sc. Thesis Sharif University of Technology Heidarzadeh, Amir (Author) ; Abedian, Ali (Supervisor)

    A chattering-free finite-time robust synchronization scheme for uncertain chaotic systems

    , Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 43 , 2019 , Pages 995-1003 ; 22286187 (ISSN) Heidarzadeh, S ; Salarieh, H ; Sharif University of Technology
    Springer International Publishing  2019
    Abstract
    This paper addresses a simple chattering-free and finite-time convergent robust synchronization scheme for a general class of disturbed master and slave chaotic systems. Unlike traditional variable structure control schemes, the proposed controller does not directly include a switching function, and chattering is avoided. The term including switching function is the input of a low-pass filter where the filtered output is used in the controller. Also, numerical differentiation of master and slave state trajectories is not required to implement the controller. Stability of the proposed controller is established using a Lyapunov stability analysis and the finite-time convergence theories.... 

    Iterated Integrals and Periods of Algebraic Fundamental Groups

    , M.Sc. Thesis Sharif University of Technology Heidarzadeh, Leila (Author) ; Jafari, Amir (Supervisor)
    Abstract
    In This thesis, we study first the analytic properties of Iterated integrals on complex line and discuss their shuffle relations and also regularization for divergent integrals, Next we turn in to Mixed Hodge theory and define a Hopf algebra of framed Mixed Hodge -Tate Structures. Associated to any iterated integral ∫ an+1 a0 dt ta1 dt ta2 ::: dttan
    we define an n-framed Mixed Hodge-Tate structure denoted by IH(a0; a1; :::; an; an+1) . These structure come from the fundamental group of Cfa1; :::; ang and for this we recall the theory of Chen and Hain for these groups. At the end calculate a coproduct formula for these elements  

    A novel robust model reference adaptive impedance control scheme for an active transtibial prosthesis

    , Article Robotica ; Volume 37, Issue 9 , 2019 , Pages 1562-1581 ; 02635747 (ISSN) Heidarzadeh, S ; Sharifi, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    In this paper, a novel robust model reference adaptive impedance control (RMRAIC) scheme is presented for an active transtibial ankle prosthesis. The controller makes the closed loop dynamics of the prosthesis similar to a reference impedance model and provides asymptotic tracking of the response trajectory of this impedance model. The interactions between human and prosthesis are taken into account by designing a second-order reference impedance model. The proposed controller is robust against parametric uncertainties in the nonlinear dynamic model of the prosthesis. Also, the controller has robustness against bounded uncertainties due to unavailable ground reaction forces and unmeasurable... 

    A novel stable robust adaptive impedance control scheme for ankle prostheses

    , Article 5th RSI International Conference on Robotics and Mechatronics, IcRoM 2017, 25 October 2017 through 27 October 2017 ; 2018 , Pages 63-68 ; 9781538657034 (ISBN) Heidarzadeh, S ; Sharifi, M ; Salarieh, H ; Alasty, A ; Sharif University of Technology
    2018
    Abstract
    A stable robust adaptive impedance control strategy is introduced here as a model-based low-level control scheme for active ankle prostheses. The effects of amputee-prosthesis and prosthesis-environment interactions are included in the controller design. An interesting feature of the proposed controller is that only shank and ankle angles and angular velocities, and ground reaction forces are required to implement the control law. In other words, no feedback from amputee-prosthesis interaction forces and moment, global or local positions, and accelerations of amputated place is required. Using a Lyapunov analysis, exponential convergence characteristics of the proposed controller are proven.... 

    Influence of electrostatic shielding of disc winding on increasing the series capacitance in transformer

    , Article 2007 IEEE Lausanne POWERTECH, Lausanne, 1 July 2007 through 5 July 2007 ; 2007 , Pages 1780-1784 ; 9781424421909 (ISBN) Bagheri, M ; Vakilian, M ; Hekmati, A ; Heidarzadeh, R ; Sharif University of Technology
    2007
    Abstract
    Strike of a lightning stroke to the high voltage terminal of a power transformer results in an impulse stress on its windings. The magnitude of the series capacitance of the windings has an important effect on the impulse voltage distribution and the stresses along the windings. Increasing the series capacitances of the windings, the impulse voltage distribution becomes more linear and the stress on the winding is reduced. So interleaved windings rather than disc windings are used in power transformer windings to increase the series capacitances. In this paper, the electrostatic shielding, used in disc windings to increase the windings series capacitance, and for linearization of its impulse... 

    Analysis of Time-Varying Epsilon-Near-Zero and Zero-Index Metamaterials

    , Ph.D. Dissertation Sharif University of Technology Heidarzadeh, Parham (Author) ; Memarian, Mohammad (Supervisor) ; Mehrany, Khashayar (Supervisor)
    Abstract
    Epsilon-near-zero media have attracted considerable attention in the last decade due to their exceptional behavior in wave propagation. The purpose of this research project is to analyze time-periodic ENZ structures. To this end, layered structures consisting of plasmonic metal and dielectric layers are used to achieve the epsilon-near-zero effect in a specific frequency range, and by time-variations of the dielectric layers, an effective time-varying (TV) ENZ is achieved. A method based on transfer matrix method is developed to analyze such structures while they are undergoing time-variations, and primarily under normal incident waves. Various structures based on such TV layered structures... 

    A hierarchical thermo-mechanical multi-scale technique for modeling of edge dislocations in nano-crystalline structures

    , Article Computational Materials Science ; Volume 141 , 2018 , Pages 360-374 ; 09270256 (ISSN) Jahanshahi, M ; Khoei, A. R ; Heidarzadeh, N ; Jafarian, N ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    In this paper, a hierarchical multi-scale technique is developed to investigate the thermo-mechanical behavior of nano-crystalline structures in the presence of edge dislocations. The primary edge dislocations are generated by proper adjustment of atomic positions to resemble discrete dislocations. The interatomic potential used to perform atomistic simulation is based on the Finnis-Sinclair embedded-atom method as many-body potential and, the Nose-Hoover thermostat is employed to control the effect of temperature. The strain energy density function is obtained for various representative volume elements under biaxial and shear loadings by fitting a fourth order polynomial in the atomistic... 

    Impulse voltage distribution in intershield disk winding VS interleaved and continuous disk winding in power transformer

    , Article 2008 IEEE 2nd International Power and Energy Conference, PECon 2008, Johor Baharu, 1 December 2008 through 3 December 2008 ; 2008 , Pages 387-392 ; 9781424424054 (ISBN) Bagheri, M ; Hekmati, A ; Heidarzadeh, R ; Salay Naderi, M ; Sharif University of Technology
    2008
    Abstract
    Strike of a lightning stroke to the high voltage terminal of a power transformer results in an impulse stress on its windings. The magnitude of the series capacitance of the windings has an important effect on the impulse voltage distribution and the stresses along the windings. Increasing the series capacitances of the windings, the impulse voltage distribution becomes more linear and the stress on the winding is reduced. So interleaved windings rather than disk windings are used in power transformer windings to increase the series capacitances. In this paper, the electrostatic shielding, used in disk windings to increase the windings series capacitance, and for linearization of its impulse... 

    Dynamic Modeling and Control of a Robotic Prosthetic Foot for Transfemoral Amputation

    , M.Sc. Thesis Sharif University of Technology Heidarzadeh Khoramabadi, Siamak (Author) ; Salarieh, Hassan (Supervisor) ; Alasty, Aria (Supervisor)
    Abstract
    The present research has dealt with the modeling and control of a robotic prosthetic foot for transfemoral amputees. In the beginning of this research, we have modeled the normal gait. In order to accomplish this modeling, we have chosen a 7-body segment skeletal model of the human body and derived the motion equations using Lagrangian equations. Then, we have developed a smooth contact model for the ground. After controlling normal gait, we have attempted to model and control the ankle and knee prosthesis. We assumed a rigid model for the ankle prosthesis and derived its dynamic equations. Then, we developed a robust model reference adaptive impedance control (RMRAIC) scheme based on the... 

    Continuum Analysis of Defects Based on Atomistic Simulat

    , M.Sc. Thesis Sharif University of Technology Heidarzadeh, Narges (Author) ; Khoei, Amir Reza (Supervisor) ; Jahanshahi, Mohsen (Co-Advisor)
    Abstract
    In this study, a new multi-scale hierarchical technique has been employed to investigate the role of temperature on nano-plates with hex atomic structure. Different number of primary edge dislocations is considered and the temperature varies from 0 up to 800 K. Primary edge dislocations are created by proper adjustment of atomic positions to resemble discrete dislocations (DD’s) and then the application of equations of motion to the relaxed configuration of this adjustment. The interatomic potential used for atomistic simulation is Finnis-Sinclair Embedded-Atom-Method (FS-EAM) as many-body interatomic potential and the Nose-Hoover thermostat has been implemented to adjust the modulation of... 

    Constrained groove pressing, cold-rolling, and post-deformation isothermal annealing: Consequences of their synergy on material behavior

    , Article Materials Chemistry and Physics ; Volume 206 , 2018 , Pages 85-93 ; 02540584 (ISSN) Pouraliakbar, H ; Jandaghi, M. R ; Heidarzadeh, A ; Jandaghi, M. M ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Stress-relieved Al-Mn-Si specimens were constrained groove pressed (CGPed) and in the following, cold-rolled under different strains of 0.47, 0.8 and 1.27. Dual strained sheets were isothermally heat treated at 150, 250, and 350 °C. Microstructure survey revealed that generated shear-bands by CGP acted as talent sites for further strain-induced grain boundary migration (SIGBM) during annealing. SEM micrographs pointed out that coarse particles (1 μm <) had not preferential positions within the aluminum matrix and often comminuted into fine dispersoids (0.5 μm >) under heavy strains. Assessment of the softening fraction (Rrec) depicted that greater accumulated strains along with higher... 

    Effectiveness Evaluation of Making Natural Childbirth Free of Charge on Household Decision in Choosing Delivery Method

    , M.Sc. Thesis Sharif University of Technology Ashtari Nakhaei, Aida (Author) ; Fatemi Ardestani, Farshad (Supervisor) ; Heidarzadeh, Mohammad (Co-Advisor)
    Abstract
    The rate of cesarean section delivery in Iran is high and during the past 14 years, leading up to 2014, kept rising. In this regard, decreasing cesarean section rate was targeted through the healthcare reform plan, which was offered by Ministry of Health and Medical Education. This plan kicked off on May4, 2014. One of the most important proceedings of this plan was making natural childbirth to be free in all hospitals, which are under the auspices of the medical universities. According to healthcare utilization models, lower prices of healthcare services, more health centers and more accessibility to them, increase the probability of using health care services. Current study evaluated the... 

    The relationship between an EFL teacher's gender and students' willingness to communicate

    , Article International Journal of Communication and Linguistic Studies ; Volume 10, Issue 4 , 2013 , Pages 17-29 ; 23277882 (ISSN) Khosravizadeh, P ; Pakzadian, S. S
    Common Ground Publishing  2013
    Abstract
    Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's... 

    An automated simple algorithm for realistic pore network extraction from micro-tomography images

    , Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 Rabbani, A ; Jamshidi, S ; Salehi, S
    2014
    Abstract
    Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images... 

    Discrimination of heart arrhythmias using novel features in heart rate phase space

    , Article Computing in Cardiology ; Volume 40 , Sept , 2013 , Pages 1035-1038 ; 23258861 (ISSN); 9781479908844 (ISBN) Moharreri, S ; Rezaei, S ; Salavatian, S
    2013
    Abstract
    In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p

    An intelligent hybrid classification algorithm integrating fuzzy rule-based extraction and harmony search optimization: Medical diagnosis applications

    , Article Knowledge-Based Systems ; Volume 220 , 2021 ; 09507051 (ISSN) Mousavi, S. M ; Abdullah, S ; Akhavan Niaki, S. T ; Banihashemi, S ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Uncertainty is a critical factor in medical datasets needed to be overcome for increasing diagnosis efficiency. This paper proposes an intelligent classification algorithm comprising a fuzzy rule-based approach, a harmony search (HS) algorithm, and a heuristic algorithm to classify medical datasets intelligently. Two fuzzy approaches, as well as orthogonal and triangular fuzzy sets, are first utilized to define the attributes of data. Then, an HS algorithm is integrated with a heuristic to generate fuzzy rules to select the best rules in the fuzzy rule-based systems. Moreover, to improve the performance of the proposed classification approach, a three-phase parameter tuning approach is...