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    Secrecy performance of friendly jammer assisted cooperative NOMA systems with internal eavesdroppers

    , Article 31st IEEE Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2020, 31 August 2020 through 3 September 2020 ; Volume 2020-August , 2020 Abolpour, M ; Aissa, S ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    In non-orthogonal multiple access (NOMA) systems, serving multiple users in shared resource blocks can allow untrusted users to overhear the messages of other users. In this context, we study a network consisting of a base station (BS), a near user and a far user, where the latter attempts to overhear the message of the former. The near user is a full-duplex (FD) node that can also act as a relay. Two operating scenarios are considered: 1) friendly jammer (FJ), where the FD node broadcasts noise for degrading the channel between the BS and the far user, while receiving data from the BS; and 2) friendly jammer relay (FJR), where, in addition to degrading the channel between the BS and the far... 

    Exponential stabilization of flexural sway vibration of gantry crane via boundary control method

    , Article JVC/Journal of Vibration and Control ; Volume 26, Issue 1-2 , 2020 , Pages 36-55 Entessari, F ; Najafi Ardekany, A ; Alasty, A ; Sharif University of Technology
    SAGE Publications Inc  2020
    Abstract
    This paper aims to develop a boundary control solution for complicated gantry crane coupled motions. In addition to the large angle sway motion, the crane cable has a flexural transverse vibration. The Hamilton principle has been utilized to derive the governing partial differential equations of motion. The control objectives which are sought include: moving the payload to the desired position; reducing the payload swing with large sway angle; and finally suppressing the cable transverse vibrations in the presence of boundary disturbances simultaneously. These simultaneous boundary control objectives make the problem challenging. The proposed control approach is based on the original... 

    Influence of river cross-section data resolution on flood inundation modeling: Case study of Kashkan river basin in western Iran

    , Article Journal of Hydrology ; Volume 584 , 2020 Geravand, F ; Hosseini, S. M ; Ataie Ashtiani, B ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    In this study, a coupling of a hydrologic and hydraulic model was utilized to assess the impacts of river geometry data resolution on the flood inundation characteristics in a data-scarce environment. Hydrological modeling incorporates soil conservation service curve-number (SCS-CN) and the geomorphologic based instantaneous unit hydrograph model (GIUH) to compute the direct runoff hydrograph in Kashkan river basin located in western Iran. 1D HEC-Geo-RAS model was used and performed to simulate inundation extent of 100-yr floods (~1800 m3/s) along 40 km reach of Kashkan river with a ground survey of river cross-section (2000 cross-sections, each including 500 data-points). The effect of... 

    Insights into the pore-scale mechanisms of formation damage induced by drilling fluid and its control by silica nanoparticles

    , Article Energy and Fuels ; Volume 34, Issue 6 , 20 May , 2020 , Pages 6904-6919 Mohammadi, M ; Mahani, H ; Sharif University of Technology
    American Chemical Society  2020
    Abstract
    The formation damage (FD) caused by the invasion of drilling fluid severely affects reservoir performance during production. Most of the published research studies which address this type of FD have been carried out at the core or field scale. Thus, the main aim of the paper is to investigate the pore-scale mechanisms of FD induced by drilling fluids and their control with silica nanoparticles (NPs) using a microfluidic approach. The proper identification of the mechanisms of FD can lead to the proper selection of NP type and concentration as well as a suitable method to remediate FD. The micromodel was designed in a way to closely simulate the cross-flow at the wellbore surface. A... 

    Delay-Optimal cooperation policy in a slotted aloha full-duplex wireless network: static approach

    , Article IEEE Systems Journal ; Volume 14, Issue 2 , 2020 , Pages 2257-2268 Vaezi, K ; Ashtiani, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    We consider a cooperative wireless communication network comprising two full-duplex (FD) nodes transmitting to a common destination based on slotted Aloha protocol. Each node has exogenous arrivals and also may relay some of the unsuccessfully transmitted packets of the other node. In this article, we find the optimal static policies of nodes in order to minimize the sum of the average transmission delays, while the average transmission delay of each node is constrained. The static policy of each node specifies the probability of accepting an unsuccessfully transmitted packet of the other node and how the node prioritizes its transmissions. We show that in the optimal policies, just the node... 

    Analytical investigation of composite sandwich beams filled with shape memory polymer corrugated core

    , Article Meccanica ; Volume 54, Issue 10 , 2019 , Pages 1647-1661 ; 00256455 (ISSN) Akbari Azar, S ; Baghani, M ; Zakerzadeh, M. R ; Shahsavari, H ; Sohrabpour, S ; Sharif University of Technology
    Springer Netherlands  2019
    Abstract
    Shape memory polymers (SMPs) are a class of smart materials which can recover their shape even after many shape changes in application of an external stimulus. In this paper, flexural behavior of a composite beam, constructed of a corrugated part filled with SMPs, is studied. This composite beam is applicable in sensor and actuator applications. Since the corrugated profiles display higher stiffness-to-mass ratio in the transverse to the corrugation direction, the beams with a corrugated part along the transverse direction are stiffer than ones with a corrugated part along the length. Employing a developed constitutive model for SMPs and the Euler–Bernoulli beam theory, the behavior of the... 

    Revealing electrical stresses acting on the surface of protoplast cells under electric field

    , Article European Journal of Mechanics, B/Fluids ; Volume 76 , 2019 , Pages 292-302 ; 09977546 (ISSN) Dastani, K ; Moghimi Zand, M ; Hadi, A ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    When cells exposed to an electric field, localized changes in the distribution of the electric field will be induced and these changes in turn lead to electrical stresses on cell surface. The electrical stresses play a key role in the cell membrane structural changes which leads to important phenomena like hydrophilic pores formation on the cell membrane resulting in the cell permeability. In this work, protoplast cell interaction with direct current (DC) electric field is investigated. The electrical stresses acted on the cell membrane in the presence of electric field are investigated numerically by a modified finite difference method, fast Immersed Interface Method (IIM). Exact solution... 

    Numerical simulation of shock-disturbances interaction in high-speed compressible inviscid flow over a blunt nose using weighted essentially non-oscillatory scheme

    , Article Wave Motion ; Volume 88 , 2019 , Pages 167-195 ; 01652125 (ISSN) Hejranfar, K ; Rahmani, S ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    In the present study, shock-disturbances interaction in high-speed compressible inviscid flow is simulated utilizing the weighted essentially non-oscillatory (WENO) scheme by employing the shock-capturing technique. For this aim, the two-dimensional Euler equations in strong conservative form are discretized by using the explicit third-order TVD Runge–Kutta scheme in time and the fifth-order WENO finite difference scheme in space. The main advantage of using the WENO scheme is its capability for properly solving the discontinuities in the domain without needing any artificial viscosity, limiter function or filter. Hence, this scheme is stable, and thus, it is suitable for simulating very... 

    A robust short-circuit fault diagnosis for high voltage DC power supply based on multisensor data fusion

    , Article 10th International Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2019, 12 February 2019 through 14 February 2019 ; 2019 , Pages 659-664 ; 9781538692547 (ISBN) Ayoubi, R ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Short-circuit fault (SCF) detection is mandatory in a high voltage DC power supply (HVPS) to prevent fatal damage. The majority of converters employ a single sensor to detect the SCF. This attribute increases the interference vulnerability of the fault detection (FD) system in the presence of noise. Therefore, miss detections and false alarms are possible to occur. Miss detections and false alarms are harmful catastrophes in most applications. A commonly used method to suppress the noise impacts is using a low-bandwidth low-pass filter. However, the use of the low-bandwidth low-pass filter reduces the speed of FD due to the filter delay. This paper proposes a fast FD algorithm based on... 

    A fault-tolerant strategy for three-phase dual active bridge converter

    , Article 10th International Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2019, 12 February 2019 through 14 February 2019 ; 2019 , Pages 253-258 ; 9781538692547 (ISBN) Davoodi, A ; Noroozi, N ; Zolghadri, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Due to several advantages, three-phase Dual Active Bridge (DAB) converter is widely used in numerous applications nowadays. On the other hand, this converter is very vulnerable to Transistor Open-Circuit Fault (TOCF). Therefore, a fault-tolerant (FT) scheme has been proposed in this paper to solve the problem. First, normal and faulty conditions are investigated, and according to the results, a fault-diagnosis (FD) approach is introduced. Using the outcomes of FD unit, a new post-fault strategy is proposed for the converter. The FD method is based on the DC component of transformer phase currents, and the basis of FT technique is shedding the faulty phase. Some benefits of the proposed... 

    IGBT Open-circuit fault diagnosis in a quasi-z-source inverter

    , Article IEEE Transactions on Industrial Electronics ; Volume 66, Issue 4 , 2019 , Pages 2847-2856 ; 02780046 (ISSN) Yaghoubi, M ; Moghani, J. S ; Noroozi, N ; Zolghadri, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, a fast and practical method is proposed for open-circuit (OC) fault diagnosis (FD) in a three-phase quasi-Z-source inverter (q-ZSI). Compared with the existing fast OC FD techniques in three-phase voltage source inverters, this method is more cost-effective since no ultrafast processor or high-speed measurement is required. Additionally, the method is independent of the load condition. The proposed method is only applicable to Z-source family inverters and is based on observing the effect of shoot-through intervals on the system variables during switching periods. The proposed algorithm includes two consecutive stages: OC detection and fault location identification. When both... 

    Simulation of three-dimensional incompressible flows in generalized curvilinear coordinates using a high-order compact finite-difference lattice boltzmann method

    , Article International Journal for Numerical Methods in Fluids ; Volume 89, Issue 7 , 2019 , Pages 235-255 ; 02712091 (ISSN) Ezzatneshan, E ; Hejranfar, K ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    Abstract
    In the present study, a high-order compact finite-difference lattice Boltzmann method is applied for accurately computing 3-D incompressible flows in the generalized curvilinear coordinates to handle practical and realistic geometries with curved boundaries and nonuniform grids. The incompressible form of the 3-D nineteen discrete velocity lattice Boltzmann method is transformed into the generalized curvilinear coordinates. Herein, a fourth-order compact finite-difference scheme and a fourth-order Runge-Kutta scheme are used for the discretization of the spatial derivatives and the temporal term, respectively, in the resulting 3-D nineteen discrete velocity lattice Boltzmann equation to... 

    Tuning the dispersion of reactive solute by steady and oscillatory electroosmotic-Poiseuille flows in polyelectrolyte-grafted micro/nanotubes

    , Article Journal of Fluid Mechanics ; 2019 , Pages 73-112 ; 00221120 (ISSN) Reshadi, M ; Saidi, M. H ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    This paper extends the analysis of solute dispersion in electrohydrodynamic flows to the case of band broadening in polyelectrolyte-grafted (soft) capillaries by accounting for the effects of ion partitioning, irreversible catalytic reaction and pulsatile flow actuation. In the Debye-Hückel limit, we present the benchmark solutions of electric potential and velocity distribution pertinent to steady and oscillatory mixed electroosmotic-pressure-driven flows in soft capillaries. Afterwards, the mathematical models of band broadening based on the Taylor-Aris theory and generalized dispersion method are presented to investigate the late-time asymptotic state and all-time evolution of... 

    A numerical study on fluid flow and acoustic characteristics of a supersonic impinging jet using vorticity confinement

    , Article Acta Acustica united with Acustica ; Volume 105, Issue 6 , 2019 , Pages 1127-1136 ; 16101928 (ISSN) Sadri, M ; Hejranfar, K ; Ebrahimi, M ; Sharif University of Technology
    S. Hirzel Verlag GmbH  2019
    Abstract
    The objective of this work is to numerically study the fluid flow and acoustic field of a supersonic impinging jet by applying the vorticity confinement (VC) method. For this aim, the three-dimensional compressible Navier-Stokes equations with the incorporation of the VC method are considered and the resulting system of equations is solved by using the sixth-order compact finite-difference scheme. To eliminate the numerical instability, a low-pass high-order filter is used. The nonreflective boundary conditions are applied for all the free boundaries and the radiated sound field is obtained by the Kirchhoff surface integration. Comparisons of the present results with the experimental data... 

    Tuning the dispersion of reactive solute by steady and oscillatory electroosmotic-Poiseuille flows in polyelectrolyte-grafted micro/nanotubes

    , Article Journal of Fluid Mechanics ; 2019 , Pages 73-112 ; 00221120 (ISSN) Reshadi, M ; Saidi, M. H ; Sharif University of Technology
    Cambridge University Press  2019
    Abstract
    This paper extends the analysis of solute dispersion in electrohydrodynamic flows to the case of band broadening in polyelectrolyte-grafted (soft) capillaries by accounting for the effects of ion partitioning, irreversible catalytic reaction and pulsatile flow actuation. In the Debye-Hückel limit, we present the benchmark solutions of electric potential and velocity distribution pertinent to steady and oscillatory mixed electroosmotic-pressure-driven flows in soft capillaries. Afterwards, the mathematical models of band broadening based on the Taylor-Aris theory and generalized dispersion method are presented to investigate the late-time asymptotic state and all-time evolution of... 

    A numerical study on fluid flow and acoustic characteristics of a supersonic impinging jet using vorticity confinement

    , Article Acta Acustica united with Acustica ; Volume 105, Issue 6 , 2019 , Pages 1127-1136 ; 16101928 (ISSN) Sadri, M ; Hejranfar, K ; Ebrahimi, M ; Sharif University of Technology
    S. Hirzel Verlag GmbH  2019
    Abstract
    The objective of this work is to numerically study the fluid flow and acoustic field of a supersonic impinging jet by applying the vorticity confinement (VC) method. For this aim, the three-dimensional compressible Navier-Stokes equations with the incorporation of the VC method are considered and the resulting system of equations is solved by using the sixth-order compact finite-difference scheme. To eliminate the numerical instability, a low-pass high-order filter is used. The nonreflective boundary conditions are applied for all the free boundaries and the radiated sound field is obtained by the Kirchhoff surface integration. Comparisons of the present results with the experimental data... 

    The role of ion partitioning in electrohydrodynamic characteristics of soft nanofluidics: Inclusion of EDL overlap and steric effects

    , Article Chemical Engineering Science ; Volume 190 , 2018 , Pages 443-458 ; 00092509 (ISSN) Reshadi, M ; Saidi, M. H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this paper, we aim to account for the partitioning of finite sized ions and electric double layer (EDL) overlapping effects on the electrostatics and hydrodynamics of soft nanofluidics by stablishing a modified Poisson-Boltzmann (MPB) equation enjoying mean field approach. The application of the present MPB equation enables us to describe the interaction between the steric effect and electrostatic repulsion of EDL ions due to permittivity difference of polyelectrolyte layer (PEL) and electrolyte solution. Utilizing the Debye-Hückel approximation pertinent to low surface potentials, we analytically derive the solutions of electric potential and velocity profiles of mixed electroosmotic and... 

    Development of a high-order compact finite-difference total Lagrangian method for nonlinear structural dynamic analysis

    , Article Applied Mathematical Modelling ; Volume 63 , 2018 , Pages 179-202 ; 0307904X (ISSN) Parseh, K ; Hejranfar, K ; Sharif University of Technology
    Elsevier Inc  2018
    Abstract
    A high-order compact finite-difference total Lagrangian method (CFDTLM) is developed and applied to nonlinear structural dynamic analysis. The two-dimensional simulation of thermo-elastodynamics is numerically performed in generalized curvilinear coordinates by taking into account the geometric and material nonlinearities. The spatial discretization is carried out by a fourth-order compact finite-difference scheme and an implicit second-order accurate dual time-stepping method is applied for the time integration. The accuracy and capability of the proposed solution methodology for the nonlinear structural analysis is investigated through simulating different static and dynamic benchmark... 

    Assessment of characteristic boundary conditions based on the artificial compressibility method in generalized curvilinear coordinates for solution of the Euler equations

    , Article Computational Methods in Applied Mathematics ; Volume 18, Issue 4 , 2018 , Pages 717-740 ; 16094840 (ISSN) Parseh, K ; Hejranfar, K ; Sharif University of Technology
    De Gruyter  2018
    Abstract
    The characteristic boundary conditions are applied and assessed for the solution of incompressible inviscid flows. The two-dimensional incompressible Euler equations based on the artificial compressibility method are considered and then the characteristic boundary conditions are formulated in the generalized curvilinear coordinates and implemented on both the far-field and wall boundaries. A fourth-order compact finite-difference scheme is used to discretize the resulting system of equations. The solution methodology adopted is more suitable for this assessment because the Euler equations and the high-accurate numerical scheme applied are quite sensitive to the treatment of boundary... 

    Preconditioned WENO finite-difference lattice Boltzmann method for simulation of incompressible turbulent flows

    , Article Computers and Mathematics with Applications ; Volume 76, Issue 6 , 2018 , Pages 1427-1446 ; 08981221 (ISSN) Hejranfar, K ; Saadat, M. H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this work, a preconditioned high-order weighted essentially non-oscillatory (WENO) finite-difference lattice Boltzmann method (WENO-LBM) is applied to deal with the incompressible turbulent flows. Two different turbulence models namely, the Spalart–Allmaras (SA) and k−ωSST models are used and applied in the solution method for this aim. The spatial derivatives of the two-dimensional (2D) preconditioned LB equation in the generalized curvilinear coordinates are discretized by using the fifth-order WENO finite-difference scheme and an implicit–explicit Runge–Kutta scheme is adopted for the time discretization. For the convective and diffusive terms of the turbulence transport equations, the...