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    An Efficient Reconfigurable Architecture in Embedded Processors

    , M.Sc. Thesis Sharif University of Technology Tamimi, Sajjad (Author) ; Asadi, Hossein (Supervisor)
    Abstract
    Nowadays, embedded processors are widely used in wide range of domains from low-power to safety-critical applications. By providing prominent features such as variant peripheral support and flexibility to partial or major design modifications, Field-Programmable Gate Arrays (FPGAs) are used in industry for implementing either an entire embedded system or a Hardware Description Language (HDL)-based processor, known as soft-core processor. FPGA-based designs, however, suffer from high power consumption, large die area, and low performance that hinders common use of soft-core processors. In this thesis, we present an efficient reconfigurable architecture to implement embedded processors in... 

    Global Existence and Asymptitic Behavior of The Boussinesq-burgers System

    , M.Sc. Thesis Sharif University of Technology Tamimi, Hengameh (Author) ; Hesaraki, Mahmoud (Supervisor)
    Abstract
    This thesis is concerned with the Boussinesq-Burgers system which models the propagation of bores by combing the dissipation, Dispasion and nonlinearity . we establish the global existence and asymptotical behavior of classical solutions of the initial value and Dirichlet boundary problem of the Boussinesq-Burgers system with the help of a lyapunov functional and the technique of Moser itrtation. Particularly we show that the solution converges to the constant stationary solution as time tends to infinity. Furthermore if we have real domain or non-hemogenous boundary condition then we will arrive constant stationary solution as time tends to infinity  

    Experimental Investigation of Fretting Fatigue of Titanium Specimens Made by Additive Manufacturing Method

    , M.Sc. Thesis Sharif University of Technology Sajjad Houshmand (Author) ; Adibnazari, Saeed (Supervisor)
    Abstract
    Additive manufacturing (AM) has gained significant attention in recent years as a novel approach to fabricate three-dimensional parts. Its advantages, including high speed, low-cost production for small-scale batches, and greater design freedom, have made it a competitive alternative to traditional manufacturing methods. However, the application of AM for components subjected to fretting fatigue requires careful evaluation. Fretting fatigue is a major cause of failure in turbines, particularly at the contact interface between turbine blade roots and disk. In this study, the influence of AM and post-processing treatments on the fretting fatigue life of Ti-6Al-4V alloy was investigated. Five... 

    An efficient SRAM-Based reconfigurable architecture for embedded processors

    , Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 38, Issue 3 , 2019 , Pages 466-479 ; 02780070 (ISSN) Tamimi, S ; Ebrahimi, Z ; Khaleghi, B ; Asadi, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Nowadays, embedded processors are widely used in wide range of domains from low-power to safety-critical applications. By providing prominent features such as variant peripheral support and flexibility to partial or major design modifications, field-programmable gate arrays (FPGAs) are commonly used to implement either an entire embedded system or a hardware description language-based processor, known as soft-core processor. FPGA-based designs, however, suffer from high power consumption, large die area, and low performance that hinders common use of soft-core processors in low-power embedded systems. In this paper, we present an efficient reconfigurable architecture to implement soft-core... 

    Face Forgery Detection Through Statistical Analysis and Local Correlation Investigation

    , M.Sc. Thesis Sharif University of Technology Asasi, Sobhan (Author) ; Ghaemmaghami, Shahrokh (Supervisor) ; Amini, Sajjad (Supervisor)
    Abstract
    Existing face forgery detection methods mainly focus on certain features of images, such as features related to image noise, local textures or frequency statistics of images for forgery detection. This makes the extracted representations and the final decision depend on the data in the database and makes it difficult to detect forgery with unknown manipulation methods. Solving this challenge, which is called the generalization challenge in artificial intelligence literature, has become the main goal of researchers in this field. In this thesis, the focus is on extracting effective features for success in forgery detection and preventing the performance of the forgery detection network from... 

    Analytical Investigation and Evaluation of Vulnerability of Deep Networks to Adversarial Perturbations

    , M.Sc. Thesis Sharif University of Technology Azizi, Shayan (Author) ; Ghaemmaghami, Shahrokh (Supervisor) ; Amini, Sajjad (Co-Supervisor)
    Abstract
    One of the most important problems in machine learning is investigating the performance of the learning algorithms, and especially deep neural networks, on adversarial examples, which are generated by imperceptibly perturbing input images, so that cause the model make a wrong prediction. Not only this line of research is important for making deep neural networks dependable, but also can help with understanding the fundamental limitations of deep neural networks, and the nature of their operation, which can in turn provide researchers with valuable insights into artificial intelligence. In this research work, we have tried to approach the topic with a mainly theoretical mindset. The method we... 

    Analysis and Enhancement of Low Voltage Ride Through Of Wind Turbines with Brushless Doubly Fed Induction Generator

    , Ph.D. Dissertation Sharif University of Technology Gholizadeh, Mahyar (Author) ; Oraee Mirzamani, Hashem (Supervisor) ; Tohidi, Sajjad (Co-Advisor)
    Abstract
    Wind energy technologies guarantee low pollution and operational costs. Using a DFIG and a fractionally rated power electronics converter gives variable speed operation with a low cost drive train. As energy policy organizations have allocated a considerable quota of wind energy generation to offshore wind farms, the absence of slip rings and brushes in the brushless DFIG (BDFIG) is an advantage for offshore wind turbines where maintenance is vital and expensive. With increasing wind power penetration in power systems, grid code requirements are an important consideration for the ride-through capability of wind farms through voltage dips, particularly for multi- MW wind turbine generators.... 

    Effects of after-body on the FIV of a right-angle triangular cylinder in comparison to circular, square, and diamond cross-sections

    , Article Ships and Offshore Structures ; 2018 ; 17445302 (ISSN) Tamimi, V ; Naeeni, T. O ; Zeinoddini, M ; Seif, M. S ; Dolatshahi Pirooz, M ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    Abstract
    This in-water experimental study deals with the effects of the after-body on the FIV response of round and sharp edge cylinders. Different circular, square, diamond, and right-angle isosceles triangular cross-sections are investigated. The triangular cylinder is examined in four different symmetrical and unsymmetrical configurations with respect to the incident flow. The current towing tank experiments form a basis for the feasibility study of the isosceles triangular cylinders for FIV energy converters. The results indicate that the cylinders with a flat side perpendicular to the flow have a galloping type of response. In contrast, the cylinders with a sharp vertex pointing the flow show a... 

    Optical bistability in fiber ring resonator containing an erbium doped fiber amplifier and quantum dot doped fiber saturable absorber

    , Article Applied Optics ; Volume 51, Issue 29 , 2012 , Pages 7016-7024 ; 1559128X (ISSN) Tofighi, S ; Farshemi, S. S ; Sajjad, B ; Shahshahani, F ; Bahrampour, A. R ; Sharif University of Technology
    2012
    Abstract
    In this paper we study the optical bistability in a double coupler fiber ring resonator which consists of an erbium doped fiber amplifier (EDFA) in half part of the fiber ring and a quantum dot doped fiber (QDF) saturable absorber in the other half. The bistability is provided by the QDF section of the ring resonator. The EDFA is employed to reduce the switching power. The transmitted and reflected bistability characteristics are investigated. It is shown that the switching power for this new bistable device is less than 10 mW  

    Effects of after-body on the FIV of a right-angle triangular cylinder in comparison to circular, square, and diamond cross-sections

    , Article Ships and Offshore Structures ; Volume 14, Issue 6 , 2019 , Pages 589-599 ; 17445302 (ISSN) Tamimi, V ; Naeeni, S. T. O ; Zeinoddini, M ; Seif, M. S ; Dolatshahi Pirooz, M ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    This in-water experimental study deals with the effects of the after-body on the FIV response of round and sharp edge cylinders. Different circular, square, diamond, and right-angle isosceles triangular cross-sections are investigated. The triangular cylinder is examined in four different symmetrical and unsymmetrical configurations with respect to the incident flow. The current towing tank experiments form a basis for the feasibility study of the isosceles triangular cylinders for FIV energy converters. The results indicate that the cylinders with a flat side perpendicular to the flow have a galloping type of response. In contrast, the cylinders with a sharp vertex pointing the flow show a... 

    Modeling and analysis of the dynamic response of an off-grid synchronous generator driven micro hydro power system

    , Article International Journal of Renewable Energy Development ; Volume 10, Issue 2 , 2021 , Pages 373-384 ; 22524940 (ISSN) Ali, W ; Farooq, H ; Rasool, A ; Sajjad, I. A ; Zhenhua, C ; Ning, L ; Sharif University of Technology
    Diponegoro university Indonesia - Center of Biomass and Renewable Energy (CBIORE)  2021
    Abstract
    This paper models and analyses the dynamic response of a synchronous generator driven off-grid micro hydro power system using Simulink tool of MATLAB software. The results are assessed from various perspectives including regulation through no load to full load and overload scenarios under normal and abnormal operating conditions. The investigation under the normal conditions of no load, linearly changing load and full load divulges that the system operates in a satisfactory manner as generator voltage and frequency remain approximately constant at 1 pu. However, at full load generator voltage and frequency drop 3% and 0.5% respectively from its nominal values but remain within prescribed... 

    Modeling and analysis of the dynamic response of an off-grid synchronous generator driven micro hydro power system

    , Article International Journal of Renewable Energy Development ; Volume 10, Issue 2 , 2021 , Pages 373-384 ; 22524940 (ISSN) Ali, W ; Farooq, H ; Rasool, A ; Sajjad, I. A ; Zhenhua, C ; Ning, L ; Sharif University of Technology
    Diponegoro university Indonesia - Center of Biomass and Renewable Energy (CBIORE)  2021
    Abstract
    This paper models and analyses the dynamic response of a synchronous generator driven off-grid micro hydro power system using Simulink tool of MATLAB software. The results are assessed from various perspectives including regulation through no load to full load and overload scenarios under normal and abnormal operating conditions. The investigation under the normal conditions of no load, linearly changing load and full load divulges that the system operates in a satisfactory manner as generator voltage and frequency remain approximately constant at 1 pu. However, at full load generator voltage and frequency drop 3% and 0.5% respectively from its nominal values but remain within prescribed... 

    Marine hydrokinetic energy harvesting performance of diamond and square oscillators in tandem arrangements

    , Article Energy ; Volume 202 , 2020 Tamimi, V ; Esfehani, M. J ; Zeinoddini, M ; Naeeni, S. T. O ; Wu, J ; Shahvaghar Asl, S ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The global demand for renewable energy sources has arisen significant research interests in marine hydrokinetic energy harvesting from flow induced vibrations. The current study deals with the hydrokinetic energy harvesting potentials of diamond and square oscillators at various inline configurations. Both the sharp edge sections and the wake induced vibrations in tandem arrangement can lead to galloping type of instability with high energy efficiency ratios. The present in-water towing tank experiments comprise 1DoF vibrating systems at Re ranging from 2 × 103 to 4.8 × 104. The results show that the upstream wake generally enhances the system efficiency and the mechanical work done by the... 

    Compact 5G millimeter-wave dual-band filter with application in filtenna

    , Article Microwave and Optical Technology Letters ; Volume 63, Issue 2 , 2021 , Pages 620-625 ; 08952477 (ISSN) Nouri, M ; Jafarieh, A ; Behroozi, H ; Mallat, N. K ; Jamaluddin, M. H ; Sajjad Abazari, S ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    In this article, a dual-band sixth order double symmetric T-slot filter is proposed for the 5G communication systems. This filter contains two duplicate square resonators and a T-shape feedline on the Rogers RT duroid 5880 substrate. Operating at the 28 and 38.5 GHz frequencies from licensed 5G frequency bands and small size make this filter appropriate for different 5G applications. Furthermore, an LC equivalent circuit for the filter has been considered that helps us to have a better sight of this filter. Measurement results show good agreement with simulations. The attenuation on the passband is less than 1 dB. In order to evaluate the filter performance besides other millimeter waves...