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naderi-shahi--sina
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Design of Digital Block of Receiver Section of Smart Antenna System
, M.Sc. Thesis Sharif University of Technology ; Haj Sadeghi, Khosro (Supervisor)
Abstract
In recent years with the increase of cellular phone subscribers, demand for high capacity networks is inevitable. For this reason, different methods have been proposed to increase the channel capacity. One method which has become popular in recent years is utilizing of Smart Antenna Systems. Smart antennas basically attempt to enhance the desired signal power and suppress the interferers by beamforming toward the DOA (direction-of-arrival) of the desired signal and nullsteering in the interferences’ DOAs. Smart Antennas first find the direction of signal sources, and then put the main gain toward the desired signal and put the nulls toward unwanted signals. As a result, we can obtain the...
Advanced Electromagnetics and Scattering Theory
, Book ; Khorasani, Sina
Springer
2015
Abstract
This book present the lecture notes used in two courses that the late Professor Kasra Barkeshli had offered at Sharif University of Technology, namely, . The prerequisite for the sequence is vector calculus and electromagnetic fields and waves. Some familiarity with Green's functions and integral equations is desirable but not necessary.
The book provides a brief but concise introduction to classical topics in the field. It is divided into three parts including annexes. Part I covers principle of electromagnetic theory. The discussion starts with a review of the Maxwell's equations in differential and integral forms and basic boundary conditions. The solution of inhomogeneous wave...
The book provides a brief but concise introduction to classical topics in the field. It is divided into three parts including annexes. Part I covers principle of electromagnetic theory. The discussion starts with a review of the Maxwell's equations in differential and integral forms and basic boundary conditions. The solution of inhomogeneous wave...
Coordinating a seller-buyer supply chain with a proper allocation of chain’s surplus profit using a general side-payment contract [electronic resource]
, Article International Journal of Industrial and Systems Engineering ; Volume 5, No. 2, Summer 2011, Page 63-79 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, seller-buyer supply chain coordination with general side-payment contracts is introduced to gain the maximum possible chain profit. In our model, the logistics costs for both buyer and seller are considered and the final demand is also supposed to be a decreasing function of the retail price. Since parties aim to maximize their individual profits, the contractual parameters are set in a way that these decisions become aligned with system optimal decisions. Therefore, a side payment contract is suggested in our model to assign the chain surplus profit to the chain members such that they have no intention to leave the coalition. Then, we change the contract into a quantity...
Design of pid controller for control of speed of the robotic fish modeled by Lighthill's large amplitude elongated body theory in linear path
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings, 13 November 2009 through 19 November 2009, Lake Buena Vista, FL ; Volume 10, Issue PART A , 2010 , Pages 117-124 ; 9780791843833 (ISBN) ; Meghdari, A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2010
Abstract
Design of robotic fish based on hydrodynamics is presented and Lighthill's Large Amplitude Elongated Body Theory (LAEBT) is used for modeling of the robotic fish in linear path. A PID controller for control of speed in linear path is designed and simulations are presented which shows its effectiveness for speed control of the robotic fish. It has been shown that in perspective of used approximate LAEBT model, the used control law maintains kinematic parameters and therefore, the associated efficiency will be maintained
On the design of robotic fish based on lighthill's small-amplitude elongated body theory
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 119-125 ; 9780791848722 (ISBN) ; Meghdari, A ; Sharif University of Technology
2009
Abstract
This paper addresses the issues of energy efficiency in robotic fish design by use of hydrodynamic models. The use of LighthilPs small-amplitude elongated body theory for designing of robotic fish, obtaining optimal kinematics and dynamic analysis with emphasis on compliant mechanism is presented. Simulation results for a sample case have demonstrated the importance of proposed approach in robotic fish design. Copyright © 2008 by ASME
Research to Provide Iranian Customer Satisfaction Index Model in Industry, Case Study: Iran Khodro Co., Golrang Co. and Kaleh Co
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
In recent decades many countries have attempted to measure and formulate customer satisfaction index (CSI), as an important factor in micro and macro-economic level. In developed country CSI has the same value of GNP. Customer Satisfaction Index model actually represents the relationship between primary factors of satisfaction and satisfaction results in the macro level for a country and includes all business aspects. In many countries, industrial companies have a wide range of products and providing Customer Satisfaction Index model for this aspect which can be a base of presenting national customer satisfaction index model. Accordingly, the main goal of this study is providing an Iranian...
Investigating the Electrochemical Behavior of Co-Zn Sulfides and Hydroxides on Copper Oxide Nano-structures Grown on Copper Foam for Application in Electrochemical Supercapacitors
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
In the first part, Co-Zn hydroxides were deposited onto CuO nanorods, and their electrochemical behavior and capacitive performance were investigated. To this end, Cu(OH)2 nanorods were grown on copper foam through a chemical process. Then, Cu(OH)2 were converted to CuO nanorods via a calcination process. In the next step, Co-Zn-OH sheets were electrodeposited on CuO nanorods. FE-SEM images of the prepared electrodes demonstrate the formation of Co-Zn-OH nanosheets onto CuO nanorods. Crucial electrochemical evaluations such as cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), rate capability, and electrochemical impedance spectroscopy (EIS) were carried out. According to the...
Photonic Crystal Cavity Quantum Optic in the Very Strong Coupling Regime
, M.Sc. Thesis Sharif University of Technology ; Khorasani, Sina (Supervisor)
Abstract
First, we peruse the intraction between a quantized light and a two level atom which has been described by Janes-Cummings-Paul Hamiltonian. By solving Heisenberg equations in Fourier space and describing electric field by a generalized-transverse Green function, we obtain spectral density for a quantum dot which is in the strong coupling to a slab photonic crystal cavity. Afterward, by solving Shrouding equations precisely we demonstrate when quantum dot is in a very strong coupling to cavity, rotate wave approximation is not reliable anymore. It means that if coupling constant gets comparable to cavity mode frequency then the prevalent approach to solve this Hamiltonian will not be correct....
Analysis of Ultra-Strong Coupling in Optical Waveguides
, M.Sc. Thesis Sharif University of Technology ; Khorasani, Sina (Supervisor)
Abstract
In this project, we were intended to study the ultra-strong coupling in optical waveguides. Hence, we analyze the interaction of an electromagnetic wave with a quantum well embedded in a dielectric slab waveguide. First, we designed a QW with and alloys, which the energy of its electron-heavy holes transition is . By exploiting the envelope function approximation, we derived the wavefunction of electrons and holes, their eigen-energies, and the dipole moment of electon-holes. For finding the wavefunction of holes and their eigen-energies, we used the Luttinger Hamiltonian. Next, we calculated the electrical susceptibility of a three level quantum system (as a model for QW), by using...
Cavity Quantum Electro-Dynamics in Ultra-Strong Coupling Regime
,
M.Sc. Thesis
Sharif University of Technology
;
Khorasani, Sina
(Supervisor)
Abstract
Cavity Quantum Electro-Dynamics (CQED) in Weak, Strong and Ultra-Strong coupling Regimes are studied. A MATLAB m-file is written which is able to solve any arbitrary CQED configuration. This program demands input data such as number of Quantum Dots, number of energy levels of each Quantum Dot, energies of each energy level of Quantum Dots, Number of cavity modes, eign-frequency of each cavity mode, coupling constant, dipole strength of each allowed transition of Quantum Dots and initial state of system from user and begins to solve the Schrodinger equation for annihilation and atomic ladder operators. In addition, coefficients of each possible ket will be calculated. Since, any approximation...
Nonlinear Torsional Vibrations of Thin Walled Beam with Semi-Analytic Methods
, Ph.D. Dissertation Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
Thin Walled Beams are widely used in engineering applications with the minimum weight design criteria, ranging from civil to aerospace and many other industrial fields. The weight reduction of the beam leads to importance of the dynamic behavior of the structure. Frequently used thin walled beams have low torsional stiffness and their torsional deformations may be of such magnitudes that it is not adequate to treat the angles of cross section rotation as small. When the vibration amplitudes are moderate or large, the geometric nonlinearity must be included and some new phenomena which do not exist in linear torsional dynamic come into play. Unfortunately, the equations of motion of nonlinear...
Design and Analysis of Delay Lines Based on Photonic Crystal Coupled Cavities
, M.Sc. Thesis Sharif University of Technology ; Khorasani, Sina (Supervisor)
Abstract
In the recent years, photonic crystal (PhC) devices vastly have been paid attention due to their ignorable loss, very low group velocity, flexibility in shape and dimension.In this thesis a PhC coupled cavity ring known as superresonator is introduced and its properties and applications is studied. Also modes of the structure are extracted through both coupled-resonator model and FDTD method, and two of its application is described and studied. Add-drop filter is one of the essential devices in WDM systems. First, an application of superresonator in designing add-drop filters is explained and a novel filter based on the superresonator is introduced and analyzed by FDTD and coupled mode...
Fidelity-based supervised and unsupervised learning for binary classification of quantum states
, Article European Physical Journal Plus ; Volume 136, Issue 3 , 2021 ; 21905444 (ISSN) ; Rezakhani, A. T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Here, we develop two quantum-computational schemes for supervised and unsupervised classification tasks in a quantum world by employing the quantum information-geometric tools of quantum fidelity and quantum search algorithm. Presuming that pure states of a set of given quantum systems (or objects) belong to one of two known classes, the objective here is to decide to which of these classes each system belongs—without knowing its state. The supervised binary classification algorithm is based on having a training sample of quantum systems whose class memberships are already known. The unsupervised binary classification algorithm, however, uses a quantum oracle which knows the class membership...
Paving property for real stable polynomials and strongly rayleigh processes
, Article Bernoulli ; Volume 28, Issue 2 , 2022 , Pages 1198-1223 ; 13507265 (ISSN) ; Barzegar, M ; Sharif University of Technology
Bernoulli Society for Mathematical Statistics and Probability
2022
Abstract
One of the equivalent formulations of the Kadison–Singer problem which was resolved in 2013 by Marcus, Spielman and Srivastava, is the “paving conjecture”. In this paper, we first extend this result to real stable polynomials. We prove that for every multi-affine real stable polynomial satisfying a simple condition, it is possible to partition its set of variables to a small number of subsets such that the “restriction” of the polynomial to each subset has small roots. Then, we derive a probabilistic interpretation of this result. We show that there exists a partition of the underlying space of every strongly Rayleigh process into a small number of sets such that the restriction of the point...
Axial-torsional vibrations of rotating pretwisted thin walled composite beams
, Article International Journal of Mechanical Sciences ; Vol. 80 , 2014 , pp. 93-101 ; ISSN: 00207403 ; Haddadpour, H ; Sharif University of Technology
2014
Abstract
Axial-torsional vibrations of rotating pretwisted thin-walled composite box beams exhibiting primary and secondary warping are investigated. Considering the nonlinear strain-displacement relations, the coupled nonlinear axial-torsional equations of motion are derived using Hamilton's principle. Ignoring the axial inertia term leads to differential equation of motion in terms of elastic torsion in the case of axially immovable beams. Centrifugal load in the presence of material anisotropy and pretwist angle leads to an induced static torque. The nonlinear equation should be linearized about the corresponding equilibrium state to obtain the linear differential equation of motion. Extended...
Comment on "vibration of turbomachinery rotating blades made-up of functionally graded materials and operating in a high temperature field" by S-Y. Oh, L. Librescu and O. Song (Acta Mech. 166, 69-87, 2003)
, Article Acta Mechanica ; Volume 218, Issue 3-4 , 2011 , Pages 375-376 ; 00015970 (ISSN) ; Haddadpour, H ; Sharif University of Technology
2011
Response to the Authors' reply to the Comment on "vibration of turbomachinery rotating blades made-up of functionally graded materials and operating in a high temperature field", doi:10.1007/s00707-010-0407-5
, Article Acta Mechanica ; Volume 218, Issue 3-4 , 2011 , Pages 379-382 ; 00015970 (ISSN) ; Haddadpour, H ; Sharif University of Technology
2011
Hybrid supercapacitors constructed from double-shelled cobalt-zinc sulfide/copper oxide nanoarrays and ferrous sulfide/graphene oxide nanostructures
, Article Journal of Colloid and Interface Science ; 2020 ; Hekmat, F ; Shahrokhian, S ; Sharif University of Technology
Academic Press Inc
2020
Abstract
Evolution of renewable energies in the era of the modernized world has been strongly tied up to the incessant development of high-performance energy storage systems benefiting from both high energy and power densities. In the present work, binder-free positive electrodes are fabricated via a facile electrochemical deposition route in which copper oxide nanorods (CuO NRs) directly grown onto the copper foam (CF) are decorated with bimetallic cobalt-zinc sulfide nanoarrays (Co-Zn-S NAs). The fabricated Co-Zn-S@CuO-CFs represent promising specific capacity of 317.03 C.g−1 at 1.76 A.g−1, along with superior cyclic stability (113% retention after 4500 cycles). Negative electrodes were further...
Hybrid supercapacitors constructed from double-shelled cobalt-zinc sulfide/copper oxide nanoarrays and ferrous sulfide/graphene oxide nanostructures
, Article Journal of Colloid and Interface Science ; Volume 585 , 2021 , Pages 750-763 ; 00219797 (ISSN) ; Hekmat, F ; Shahrokhian, S ; Sharif University of Technology
Academic Press Inc
2021
Abstract
Evolution of renewable energies in the era of the modernized world has been strongly tied up to the incessant development of high-performance energy storage systems benefiting from both high energy and power densities. In the present work, binder-free positive electrodes are fabricated via a facile electrochemical deposition route in which copper oxide nanorods (CuO NRs) directly grown onto the copper foam (CF) are decorated with bimetallic cobalt-zinc sulfide nanoarrays (Co-Zn-S NAs). The fabricated Co-Zn-S@CuO-CFs represent promising specific capacity of 317.03 C.g−1 at 1.76 A.g−1, along with superior cyclic stability (113% retention after 4500 cycles). Negative electrodes were further...
3D flower-like nickel cobalt sulfide directly decorated grassy nickel sulfide and encapsulated iron in carbon sphere hosts as hybrid energy storage device
, Article Applied Surface Science ; Volume 558 , 2021 ; 01694332 (ISSN) ; Hekmat, F ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Developing high-performance supercapacitors is of great significance in the area of renewable energies by virtue of having both high energy and power densities. In this work, an innovative strategy is employed for the fabrication of binder-free binary nickel–cobalt-sulfide (NCS) nanosheets (NSs) directly decorated onto the hydrothermal nickel-sulfide (Ni3S2) nanowires (NWs) as the positive electrodes. The NCS/Ni3S2-nickel foam (NF) positive electrodes rendered superior specific capacity of 499.1 mAh.g−1 at 6 A.g−1. Encapsulated iron into the carbon sphere hosts (Fe-HTCSs) are used as the negative counterparts, exhibiting remarkable specific capacitance of 336.6 F.g−1 (at 0.1 A.g−1). The...