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    Autonomous runway alignment of fixed-wing unmanned aerial vehicles in landing phase

    , Article 5th International Conference on Autonomic and Autonomous Systems, ICAS 2009, Valencia, 20 April 2009 through 25 April 2009 ; 2009 , Pages 208-213 ; 9780769535845 (ISBN) Pouya, S ; Saghafi, F ; Sharif University of Technology
    2009
    Abstract
    In this paper, the development of a controller for autonomous lateral alignment of fixed-wing Unmanned Aerial Vehicles (UAVs) with runway centerline in landing phase is presented. Fuzzy Logic Control (FLC) is used in order to enable the vehicle to mimic the decision making procedure that a pilot follow in the same situation. Also, for longitudinal motion controller design for the UAV to follow a pre-defined trajectory, the pole-placement technique is used. It is assumed that the runway relative position and orientation are provided by a built in vision system and its associated image processing unit. The performance of the controller in the presence of the Gaussian noises is investigated by... 

    Measuring limb darkening of stars in high-magnification microlensing events by the Finite Element Method

    , Article Monthly Notices of the Royal Astronomical Society ; Volume 494, Issue 1 , 2020 , Pages 584-597 Golchin, L ; Rahvar, S ; Sharif University of Technology
    Oxford University Press  2020
    Abstract
    The finite-size effect in gravitational microlensing provides a possibility to measure the limb darkening of distant stars. We use the Finite Element Method (FEM) as an inversion tool for discretization and inversion of the magnification-limb darkening integral equation. This method makes no explicit assumption about the shape of the brightness profile more than the flatness of the profile near the centre of the stellar disc. From the simulation, we investigate the accuracy and stability of this method and we use regularization techniques to stabilize it. Finally, we apply this method to the single lens, high-magnification transit events of OGLE-2004-BLG-254 (SAAO-I),... 

    Measuring Limb Darkening of Distant Stars Using Microlensing Events by Finite Element Method

    , Ph.D. Dissertation Sharif University of Technology Golchin, Laya (Author) ; Rahvar, Sohrab (Supervisor)
    Abstract
    The finite-size effect in gravitational microlensing provides a possibility to measure the variation of surface brightness of stars from centre to limb which is called limb darkening profile. Measuring limb darkening profile provides information about star atmosphere. It is also useful in other fields of astrophysics. In this thesis we develop a numerical method to recover limb darkening of source stars from single lens microlensing light curves with finite source effect in which the lens transits the source disk. We use the Finite Element Method (FEM) as an inversion tool for discretization and inversion of the finite source effect integral equation. This method makes no explicit assumption... 

    Improved optimal control technique for control of parallel three- phase inverters

    , Article 2009 International Conference on Electric Power and Energy Conversion Systems, EPECS 2009, Sharjah, 10 November 2009 through 12 November 2009 ; 2009 ; 9789948427155 (ISBN) pouya, H. R. N ; Mokhtari, H ; Sharif University of Technology
    2009
    Abstract
    This paper proposes a high performance voltage tracking and current sharing among parallel connected inverters by applying optimal control and minimizing the cost function. The control system forces the voltage of load to track the voltage reference, and the current of all inverters becomes equal. Therefore, both current sharing and voltage tracking are obtained. In addition, the smallest input energy and simplicity in control circuit are the other advantages of the suggested method. To show the performance of the proposed control scheme, the simulations with two-modular practical systems are performed and the results are provided. The results indicate that the control objectives are... 

    Seismic Response of “Karroon III” DAM to Non-Uniform Ground Motions

    , M.Sc. Thesis Sharif University of Technology Pouya, Mohammad Reza (Author) ; Ghaemian, Mohsen (Supervisor)
    Abstract
    Usually in analysis of arch dams, applied seismic motions on dam-foundation interface are assumed to be uniform. This is while that recorded motions show non-uniform accelerations in dam-foundation interface. Analyzing of the dam under this non-uniform accelerations we can find the importance of this assumption in analysis of arch dams. Two earthquakes were excited “KAROON III” dam at 20.11.2007 and 21.11.2007. The respective motions were recorded by the array of accelerometers that has been installed on the dam. The recorded motions, indicated non-uniformity of excitations in accelerometers were installed near the dam-foundation interface. Therefore this data provided an opportunity to... 

    Thermal analysis of RCC dams during construction considering different ambient boundary conditions at the upstream and downstream faces

    , Article Journal of Civil Structural Health Monitoring ; Volume 12, Issue 3 , 2022 , Pages 487-500 ; 21905452 (ISSN) Pouya, M. R ; Sohrabi Gilani, M ; Ghaemian, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Thermal analysis of Roller Compacted Concrete (RCC) dams is generally carried out considering identical ambient boundary conditions at upstream and downstream faces. For the case of Shahri-Kor Dam (an RCC dam with a height of 57 m), recorded thermal data depicts a considerable difference between upstream and downstream ambient temperatures, especially during cold months. This paper investigates how taking this difference into account can affect the thermal response of the dam. For this purpose, two thermal analyses are carried out with and without consideration of these different ambient boundary conditions (DABC). Consequently, the computed temperatures at representative points are compared... 

    The effect of non-uniformity in ground motions on the seismic response of arch dams

    , Article SN Applied Sciences ; Volume 3, Issue 3 , 2021 ; 25233971 (ISSN) Pouya, M. R ; Sohrabi Gilani, M ; Ghaemian, M ; Sharif University of Technology
    Springer Nature  2021
    Abstract
    Recorded ground accelerations at various locations of Karun III Dam during November 20, 2007, were recorded by an array of accelerometers located on the dam. In terms of amplitude and phase, these accelerations show non-uniformities in different elevations. In this paper, the effect of these non-uniform ground motions on the seismic response of the dam taking dam-reservoir-foundation interaction into account is investigated. The EACD-3D-2008 finite element program and ABAQUS Software are used for carrying out the seismic analyses. For this purpose, time histories of the earthquake accelerations are interpolated at nodal points located on the dam foundation interface. The analysis has been... 

    Evaluating the Changes in the Mean Vector and Covariance Matrix of EDP Distribution for different IM and Ground Motion Selections

    , M.Sc. Thesis Sharif University of Technology Golchin, Pouya (Author) ; Rahimzadeh Rofouei, Fayyaz (Supervisor)
    Abstract
    In this study, the changes in the mean vector and the covariance matrix of engineering demand parameter (EDP) distributions for different intensity measures and ground motion selections is evaluated. Although, the changes in the mean distribution of EDPs have been extensively studied in the literature, but the changes in the covariance matrix of EDPs distributions caused by ground motion selections has not been paid the due attention. In other words, no study has specifically looked into the effect of intensity measure changes on the covariance matrix; therefore, for the purpose of this study, several steel frame models were considered with perimeter special moment resisting frames (SMRF).... 

    Development of a Covering Location Model in Congested Networks

    , M.Sc. Thesis Sharif University of Technology Golchin Khiabani Azar, Negar (Author) ; Shavandi, Hassan (Supervisor)
    Abstract
    Plants, distribution centers, and other facilities generally function for years or decades, during which time the environment in which they operate may change substantially. Costs, demands, travel times, and other inputs to classical facility location models may be highly uncertain. So when making decisions of location considering the factors that may change is beneficial. In this thesis a version of covering location model under uncertainty in a congested system is proposed. The aim is to locate m facilities to maximize the captured customer utility, having in mind that there may be up to q facilities established in future; the only information at hand about the number of the new facilities... 

    Design, construction, and evaluation of “sensor lock”: an electromechanical stance control knee joint

    , Article Disability and Rehabilitation: Assistive Technology ; 2017 , Pages 1-8 ; 17483107 (ISSN) Arazpour, M ; Ahmadi Bani, M ; Baniasad, M ; Samadian, M ; Golchin, N ; Sharif University of Technology
    2017
    Abstract
    Background and aim: Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost. Method: Ten able-bodied (AB) participants and two (knee ankle foot orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each... 

    Design, construction, and evaluation of “sensor lock”: an electromechanical stance control knee joint

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 13, Issue 3 , 2018 , Pages 226-233 ; 17483107 (ISSN) Arazpour, M ; Ahmadi Bani, M ; Baniasad, M ; Samadian, M ; Golchin, N ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    Abstract
    Background and aim: Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost. Method: Ten able-bodied (AB) participants and two (knee ankle foot orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; March , 2018 , Pages 1-5 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    Abstract
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 14, Issue 4 , 2019 , Pages 333-337 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were...