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Encrypted internet traffic classification using a supervised spiking neural network
, Article Neurocomputing ; Volume 503 , 2022 , Pages 272-282 ; 09252312 (ISSN) ; Delpech, F ; Aguilar Melchor, C ; Zimmer, R ; Shouraki, S. B ; Masquelier, T ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Internet traffic recognition is essential for access providers since it helps them define adapted priorities in order to enhance user experience, e.g., a high priority for an audio conference and a low priority for a file transfer. As internet traffic becomes increasingly encrypted, the main classic traffic recognition technique, payload inspection, is rendered ineffective. Hence this paper uses machine learning techniques looking only at packet size and time of arrival. For the first time, Spiking neural networks (SNNs), which are inspired by biological neurons, were used for this task for two reasons. Firstly, they can recognize time-related data packet features. Secondly, they can be...
Enhanced ORR catalytic activity of rare earth-doped Gd oxide ions in a CoFe2O4 cathode for low-temperature solid oxide fuel cells (LT-SOFCs)
, Article Ceramics International ; Volume 48, Issue 19 , 2022 , Pages 28142-28153 ; 02728842 (ISSN) ; Akbar, M ; Yousaf Shah, M. A. K ; Noor, A ; Lu, Y ; Akhtar, M. N ; Mushtaq, N ; Hu, E ; Yan, S ; Zhu, B ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The search for cathode materials with fast oxygen reduction reaction (ORR) catalytic activities and high ionic conductivity is the key obstacle to SOFCs commercialization and its operation at low temperatures. In order to search for a cathode with enhanced catalytic functionality, herein we report a single-phase CoFe2O4 (CFO) and CoGd0.2Fe1.80O4 (CGFO), which can be employed as an active cathode to improve electrocatalytic ORR functionalities at low temperature. It is found that CGFO having enriched oxygen vacancies exhibits the least polarization resistance (RP) of 0.42 Ωcm2 compared to the pure CFO which shows polarization resistance of 0.56 Ω cm2 under H2/air conditions. Furthermore,...
Observer-based controller for treatment of hepatitis C infection using fractional order model
, Article Mathematical Methods in the Applied Sciences ; Volume 45, Issue 17 , 2022 , Pages 10689-10709 ; 01704214 (ISSN) ; Shahrokhi, M ; Pishro, A ; Sharif University of Technology
John Wiley and Sons Ltd
2022
Abstract
In this study, a stable observer-based feedback controller has been designed for treatment of hepatitis C infectious disease under interferon (IFN) therapy. In order to consider the memory behavior and uncertain nature of this biological system, an unknown dynamics fractional-order (FO) model has been utilized for describing the interactions between the healthy cells, infected cells, and hepatitis C virus (HCV). To cope with unknown dynamics, the fuzzy logic system (FLS) has been utilized. Limitation of the drug efficacy due to its negative side effects has been taken into account as an input saturation. In order to estimate the unknown states which are required for treatment, a full-order...
Efficient reduction of organic pollutants by novel magnetic Bi2S3/NiCo2O4 MOF- derived composite: Exprimental and DFT investigation
, Article Journal of Molecular Liquids ; Volume 367 , 2022 ; 01677322 (ISSN) ; Akbarzadeh, E ; Gholami, M. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Novel Bi2S3/NiCo2O4 nanocomposites (BS/NCO) with various mass ratios were prepared using NiCo-MOF as precursor. The morphology, composition and structure of the as-prepared catalysts were studied by different techniques such as FE-SEM, EDX, XRD, FT-IR, VSM and BET. The as-synthesized composite with 20 % Bi2S3 (%20 BS/NCO) demonstrated the best performance in reduction reaction of 4-nitrophenol (4-NP). The enhanced catalytic activity of %20 BS/NCO composite compared to the Bi2S3 and NiCo2O4 can be assigned to the optimized synergistic effects between the two pristine materials. Thermodynamic parameters and the activation energy of the reaction in the presence of %20 BS/NCO composite were...
Band-structure calculation of SH-waves in 1D hypersonic nano-sized phononic crystals with deformable interfaces
, Article Mechanics of Materials ; Volume 171 , 2022 ; 01676636 (ISSN) ; Shodja, H. M ; Sanati, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Nanoscopic interface deformations between the layers in a superlattice have a great impact on its phononic band-structure. This work aims to study the SH-wave band-structure in one-dimensional (1D) multilayer hypersonic nano-sized phononic crystals with consideration of local deformations at the interfaces of the layers. At this scale, the traditional theory of elasticity is unable to capture the realistic forbidden and permitted frequencies. Thus, in light of surface/interface elastodynamics theory for nanostructures with deformable interfaces, a mixed variational method which accounts for the notion of interface elasticity, deformability, and inertia is introduced in the present work. For...
A compatible mixed finite element method for large deformation analysis of two-dimensional compressible solids in spatial configuration
, Article International Journal for Numerical Methods in Engineering ; Volume 123, Issue 15 , 2022 , Pages 3530-3566 ; 00295981 (ISSN) ; Sharif University of Technology
John Wiley and Sons Ltd
2022
Abstract
In this article, a new mixed finite element formulation is presented for the analysis of two-dimensional compressible solids in finite strain regime. A three-field Hu–Washizu functional, with displacement, displacement gradient and stress tensor considered as independent fields, is utilized to develop the formulation in spatial configuration. Certain constraints are imposed on displacement gradient and stress tensor so that they satisfy the required continuity conditions across the boundary of elements. From theoretical standpoint, simplex elements are best suited for the application of continuity constraints. The techniques that are proposed to implement the constraints facilitate their...
Efficient simulation of resonance Raman spectra with tight-binding approximations to density functional theory
, Article Journal of Chemical Physics ; Volume 157, Issue 8 , Volume 157, Issue 8 , 2022 ; 00219606 (ISSN) ; Jamshidi, Z ; Visscher, L ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
Resonance Raman spectroscopy has long been established as one of the most sensitive techniques for detection, structure characterization, and probing the excited-state dynamics of biochemical systems. However, the analysis of resonance Raman spectra is much facilitated when measurements are accompanied by Density Functional Theory (DFT) calculations that are expensive for large biomolecules. In this work, resonance Raman spectra are therefore computed with the Density Functional Tight-Binding (DFTB) method in the time-dependent excited-state gradient approximation. To test the accuracy of the tight-binding approximations, this method is first applied to typical resonance Raman benchmark...
Atomistic study of the effect of crystallographic orientation on the twinning and detwinning behavior of NiTi shape memory alloys
, Article Computational Materials Science ; Volume 203 , 2022 ; 09270256 (ISSN) ; Izadifar, M ; Dolado, J. S ; Ramazani, A ; Sadrnezhaad, S. K ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Understanding the effect of crystallographic orientation on the twinnin/detwinning mechanisms in NiTi shape memory alloys at an atomistic scale can help to control and tune the mechanical properties and failure behavior of such materials. In this work, we employed classical molecular dynamics (MD) and density functional theory (DFT) computational methods to better understand how twinning and detwinning occurs through a combination of slip, twin, and shuffle on 〈0 1 0〉, 〈1 1 0〉, and 〈1 1 1〉 crystallographic orientations under uniaxial tensile test. Elastic constants including Young's Modulus (E), Bulk modulus (B), Poisson's ratio (ν), and Shear Modulus (G) are obtained and computed for...
A new approach for simulating D-T fusion interaction using the Geant4 toolkit
, Article Journal of Instrumentation ; Volume 17, Issue 3 , 2022 ; 17480221 (ISSN) ; Moshkbar Bakhshayesh, K ; Sharif University of Technology
IOP Publishing Ltd
2022
Abstract
In this study, the Geant4 toolkit is utilized to present a new approach for simulation of the D-T interaction. The neutron production cross-section and the energy/angle distribution of neutrons produced as the D-T data libraries are incorporated in the Geant4, and their performance is evaluated. The spectra shape of the produced neutrons of the D-T interaction simulated by the Geant4 show good agreement compared to the results of the comparative codes (i.e. MCUNED, ENEA-JSI, and DDT). However, some differences are observed, especially, in angular range of 90-95 degrees. The reason for these differences as well as the results of the proposed approach in comparison with the results of the...
Comments on 'fractional-order sliding mode approach of buck converters with mismatched disturbances'
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 69, Issue 3 , 2022 , Pages 1381-1382 ; 15498328 (ISSN) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In this letter, it is verified that the main result of the above article [1] on converging the voltage tracking error of a buck converter controlled by a fractional-order sliding mode controller cannot be logically justified. The root cause of this inconsistency, which is an improper use of an inequality, is discussed. © 2004-2012 IEEE
Sensitivity analysis of simple methods in determination of offshore jacket structures levels stiffness
, Article Journal of Marine Science and Technology (Japan) ; Volume 27, Issue 1 , 2022 , Pages 619-636 ; 09484280 (ISSN) ; Ahmadi, A ; Sharif University of Technology
Springer Japan
2022
Abstract
Dynamic analyses are necessary problems in offshore jacket structures design and assessment. These analyses have various applications in recognition of dynamic behavior, fatigue analysis, damage detection, etc. Natural frequencies and mode shapes, as inherent vibrational features of a structure, are key parameters in referred analyses. These parameters are mainly affected by mass and stiffness matrices and slightly by damping. Therefore, it is more important to estimate the stiffness matrix of a structure accurately, especially in stiff structures such as offshore jacket platforms. In many cases, the stiffness of levels is required. For example, it can be useful in the construction of an...
An integrative method to increase the reliability of conventional double emulsion method
, Article Analytica Chimica Acta ; Volume 1197 , 2022 ; 00032670 (ISSN) ; Afjoul, H ; Shamloo, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Polymeric microspheres which can load biomolecules, cells and active agents play an important role in tissue engineering and drug delivery systems. The conventional double emulsion method has been frequently used to fabricate polymeric microspheres. However, this method has two major shortcomings: the complicated fabrication process which makes it difficult to predict the characteristics of the final microspheres while the size distribution of the microspheres has a wide range. In this study, we eliminate the shortcomings of the conventional double emulsion method and increase its performance without decreasing its high production rate. This can make the proposed modified method a promising...
Discrete-modulation measurement-device-independent continuous-variable quantum key distribution with a quantum scissor: exact non-Gaussian calculation
, Article Optics Express ; Volume 30, Issue 7 , 2022 , Pages 11400-11423 ; 10944087 (ISSN) ; Golshani, M ; Bahrampour, A ; Sharif University of Technology
Optica Publishing Group (formerly OSA)
2022
Abstract
In this paper, we study non-Gaussian discrete-modulated measurement-deviceindependent continuous-variable quantum key distribution protocol equipped with a proposed quantum scissor at the receiver side. Our suggested scissor truncates all multiphoton number states with four or more photons and amplifies remaining photon number states in a probabilistic way. Using exact non-Gaussian calculation, we find that quantum scissor meliorates the fidelity and entanglement between two legitimate parties Alice and Bob, at long distances. Therefore, quantum scissor enhances the continuous-variable quantum key distribution protocol range. Examination of the system for different values of the excess noise...
Monoelemental two-dimensional iodinene nanosheets: A first-principles study of the electronic and optical properties
, Article Journal of Physics D: Applied Physics ; Volume 55, Issue 13 , 2022 ; 00223727 (ISSN) ; Stampfl, C ; Faraji, M ; Mortazavi, B ; Fadlallah, M. M ; Nguyen, C. V ; Fazeli, S ; Ghergherehchi, M ; Sharif University of Technology
IOP Publishing Ltd
2022
Abstract
Very recently, two-dimensional (2D) iodinene, a novel layered and buckled structure has been successfully fabricated (Qian et al 2020 Adv. Mater. 32 2004835). Motivated by this latest experimental accomplishment, for the first time we conduct density functional theory, first-principles calculations to explore the structural, electronic, and optical properties of monolayer, few-layer and bulk iodinene. Unlike the majority of monoelemental 2D lattices, iodinene is predicted to be an intrinsic semiconductor. On the basis of calculations using the generalized gradient approximation of Perdew-Burke-Ernzerhof for the exchange-correlation functional and the Heyd-Scuseria-Ernzerhof (HSE06)...
Electronic polarization effects on membrane translocation of anti-cancer drugs
, Article Physical Chemistry Chemical Physics ; Volume 24, Issue 20 , 2022 , Pages 12281-12292 ; 14639076 (ISSN) ; Lund, M ; Ejtehadi, M. R ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Free-energy calculations are crucial for investigating biomolecular interactions. However, in theoretical studies, the neglect of electronic polarization can reduce predictive capabilities, specifically for free-energy calculations. To effectively mimick polarization, we explore a Charge Switching (CS) model, aiming to narrow the gap between computational and experimental results. The model requires quantum-level partial charge calculations of the molecule in different environments, combined with atomistic MD simulations. Studying three different anti-cancer drug molecules with three different phospholipid membranes, we show that the method significantly improves agreement with available...
Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)
, Article Arabian Journal of Chemistry ; Volume 15, Issue 5 , 2022 ; 18785352 (ISSN) ; Khayatkashani, M ; Soltani, N ; Yousif, Q. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN)6]3−/4− increased. Process of oxidation, energy...
Pathwise grid valuation of fixed-income portfolios with applications to risk management
, Article Heliyon ; Volume 8, Issue 7 , 2022 ; 24058440 (ISSN) ; Chaghazardi, A ; Arian, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Numerical calculation of Value-at-Risk (VaR) for large-scale portfolios poses great challenges to financial institutions. The problem is even more daunting for large fixed-income portfolios as their underlying instruments have exposure to higher dimensions of risk factors. This article provides an efficient algorithm for calculating VaR using a historical grid-based approach with volatility updating and shows its efficiency in computational cost and accuracy. Our VaR computation algorithm is flexible and simple, while one can easily extend it to cover other nonlinear portfolios such as derivative portfolios on equities and FX securities. © 2022
Design and optimization of a large-scale permanent magnet synchronous generator
, Article Scientia Iranica ; Volume 29, Issue 1 D , 2022 , Pages 217-229 ; 10263098 (ISSN) ; Rezazadeh, G ; Alipour Sarabi, R ; Tahami, F ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
Direct-drive permanent magnet synchronous generators enjoy numerous advantages including improved reliability, low maintenance, long life, and developed performance characteristics. In recent years, many researchers have worked on these generators to enhance their performance, especially for the wind turbine application. The focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then, the winding function method is used to model the generator and calculate its output characteristics analytically. The analytical results of the designed generator are validated using Finite Element Analysis (FEA) and it is demonstrated that...
A full pipeline of diagnosis and prognosis the risk of chronic diseases using deep learning and Shapley values: The Ravansar county anthropometric cohort study
, Article PLoS ONE ; Volume 17, Issue 1 January , 2022 ; 19326203 (ISSN) ; Shohaimi, S ; Salari, N ; Kiaei, A. A ; Najafi, F ; Khazaei, S ; Niaparast, M ; Abdollahi, A ; Mohammadi, M ; Sharif University of Technology
Public Library of Science
2022
Abstract
Anthropometry is a Greek word that consists of the two words "Anthropo"meaning human species and "metery"meaning measurement. It is a science that deals with the size of the body including the dimensions of different parts, the field of motion and the strength of the muscles of the body. Specific individual dimensions such as heights, widths, depths, distances, environments and curvatures are usually measured. In this article, we investigate the anthropometric characteristics of patients with chronic diseases (diabetes, hypertension, cardiovascular disease, heart attacks and strokes) and find the factors affecting these diseases and the extent of the impact of each to make the necessary...
Metal-Organic cubane cage with trimethylplatinum(IV) vertices
, Article Inorganic Chemistry ; Volume 61, Issue 1 , 2022 , Pages 15-19 ; 00201669 (ISSN) ; Jamali, S ; Mahmoudi, S ; Samouei, H ; Nayeri, S ; Chabok, S. M. J ; Jamshidi, Z ; Sharif University of Technology
American Chemical Society
2022
Abstract
Herein we describe the synthesis and characterization of the first platinum(IV) metal-organic cage [(Me3PtIV)8(byp)12](OTf)8 (2), in which the organometallic moieties trimethylplatinum(IV) (PtMe3) occupied the corners of a cubane structure and 4,4′-bipyridine ligands used as linkers. The first-principles density functional theory calculations showed that the highest occupied molecular orbitals were localized on the PtMe3 moieties, while the lowest unoccupied molecular orbitals were distributed on the organic linkers. © 2021 American Chemical Society