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asl-asgharian-sardroud--asghar
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An Anonymity Approach Using Cooprerative Security
, M.Sc. Thesis Sharif University of Technology ; Jalili, Rasoul (Supervisor)
Abstract
Providing anonymity in communications is one of the major requirements for the preserving the privacy of users using communication networks. There are several protocols for transmitting anonymous message in public communication networks. DC-Nets can be considered as an important solution to anonymous communications because they provide perfect anonymity; however, their high message and bit complexity is a major obstacle in their practical usage. All DC-Net based protocols provide anonymity of sender and receiver by establishing some anonymous channels for transmission of messages. Each execution of the DC-Net protocol acts as an anonymous channel, which only one participant can send his...
Numerical Study of Vascular Shear Stress Effects on Blood Clotting Processes
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Blood clotting and clot formation in damaged vessels are vital mechanisms of the body. Any disorder in performing this mechanism leads to various problems such as excessive bleeding or, on the contrary, causes vascular occlusion and diseases such as embolism. Due to the importance of this issue, extensive research has been done to understand this phenomenon and the factors affecting it. In this thesis, the effect of shear stress, coagulation factor concentration and wound location in coronary bifurcation on clot formation and growth and its interaction with velocity field is numerically investigated. Blood flow is modeled non-Newtonian with Carreau-Yasuda model. Various chemical species...
Prevention of gestational diabetes mellitus (GDM) and probiotics: Mechanism of action: A review
, Article Current Diabetes Reviews ; Volume 16, Issue 6 , 2020 , Pages 538-545 ; Bagheri, N ; Mohammad Alizadeh Charandabi, S ; Kashani, N ; Mobaraki Asl, N ; Mirghafurvand, M ; Asgharian, H ; Ansari, F ; Pourjafar, H ; Sharif University of Technology
Bentham Science Publishers
2020
Abstract
Background: Gestational Diabetes Mellitus (GDM) is a health problem that is increasing around the world. Introduction: Prevention of GDM, rather than treatment, could have several benefits in terms of both health and economic cost. Even a slight reduction in maternal glucose in non-diabetic women, particularly in women at high risk for GDM, may have significant benefits for pregnancy results and the future health of off-springs. Probiotics are a relatively new intervention, which are assessed by mothers’ metabolism, and can reduce blood sugar levels, prevent gestational diabetes and reduce the maternal and fetal complications resulting from it. The aim of this study was to review the studies...
Functional Connectivity in Depressive Disorder Using Functional Magnetic
Resonance Imaging Data in Auditory Stimulation Mode
,
M.Sc. Thesis
Sharif University of Technology
;
Fatemizadeh, Emadeddin
(Supervisor)
Abstract
Evidence shows that people with depressive disorder show altered functional connectivity in some of the parts of the brain. The functional characteristics of these brain areas in people with this disorder have not been completely determined. On the other hand, some researchers have rejected the static nature of functional connectivity and stated that functional connectivity changes over time. Measuring brain activity non-invasively with functional magnetic resonance imaging increases our understanding of brain organizations and functional mechanisms, so in this study, we used the functional magnetic resonance imaging data of 18 healthy subjects and 18 subjects with depression. Method: The...
Proposing an optimum model for time estimation of construction projects in Iranian gas refineries
, Article Engineering Journal ; Volume 21, Issue 5 , 2017 , Pages 285-304 ; 01258281 (ISSN) ; Majrouhi Sardroud, J ; Mofid, M ; Sharif University of Technology
2017
Abstract
Time management can be effective in a project when the project schedule is based on comprehensive time scheduling. In the industries with complicated processes, many uncertainties and risks affect the timing of projects. Considering the very low reliability of the project planning in certainty-based approach, using more secure models for control and interact with uncertainty should be placed on the agenda. Iranian Gas Company has been using risk management to manage probable uncertainties in construction projects but in the field of possible uncertainties, actions are very scarce. This article aims to propose an optimum model based on the integrated risk management and fuzzy expert systems...
Presenting a model based on fuzzy application to optimize the time of IBS projects in gas refineries
, Article MATEC Web of ConferencesVolume 95, 9 February 2017 ; Volume 95 , 2017 ; 2261236X (ISSN) ; Majrouhi Sardroud, J ; Mofid, M ; Sharif University of Technology
EDP Sciences
2017
Abstract
Nowadays, the construction industry has started to embrace IBS as a method of attaining better construction quality and productivity and reducing risks related to occupational safety and health. The built of pre-fabricated component in factories reduces many problems related to lack of purposing uncertainty in scheduling calculation and time management of projects. In the case of using IBS method for managing time in projects, former studies such as Allan Tay's research, indicates that this method can save up at least 29% of overall completion period versus the conventional method. But beside mentioned advantages of this technical method, the projects could be optimized more and more in...
Should fast-food franchisees pursue entrepreneurial orientation?
, Article Entrepreneurship Research Journal ; 2021 ; 21946175 (ISSN) ; Tasavori, M ; Andersen, J ; Sharif University of Technology
De Gruyter Open Ltd
2021
Abstract
Although it is widely accepted that entrepreneurial orientation (EO) improves firm performance, scholars have advised that particular attention should be paid to the context. In this research, we investigate a less explored context of franchising where business systems and procedures are usually dictated to franchisees by franchisors. Therefore, whether a franchisor should allow franchisees to pursue EO (innovativeness, proactiveness, risk-taking, competitive aggressiveness, and autonomy) is not clear. In the context of franchising, the majority of prior studies have mainly focused on the employment of EO as a unidimensional construct and at the franchisor level. In this research, we take a...
Should fast-food franchisees pursue entrepreneurial orientation?
, Article Entrepreneurship Research Journal ; Volume 13, Issue 2 , 2023 , Pages 185-220 ; 21946175 (ISSN) ; Tasavori, M ; Andersén, J ; Sharif University of Technology
De Gruyter Open Ltd
2023
Abstract
Although it is widely accepted that entrepreneurial orientation (EO) improves firm performance, scholars have advised that particular attention should be paid to the context. In this research, we investigate a less explored context of franchising where business systems and procedures are usually dictated to franchisees by franchisors. Therefore, whether a franchisor should allow franchisees to pursue EO (innovativeness, proactiveness, risk-taking, competitive aggressiveness, and autonomy) is not clear. In the context of franchising, the majority of prior studies have mainly focused on the employment of EO as a unidimensional construct and at the franchisor level. In this research, we take a...
Band-gap narrowing and electrochemical properties in N-doped and reduced anodic TiO2 nanotube arrays
, Article Electrochimica Acta ; Volume 270 , 2018 , Pages 245-255 ; 00134686 (ISSN) ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was...
Improved efficiency in front-side illuminated dye sensitized solar cells based on free-standing one-dimensional TiO2 nanotube array electrodes
, Article Solar Energy ; Volume 184 , 2019 , Pages 115-126 ; 0038092X (ISSN) ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Although morphological disorder of nanotube structure is further down than the nanoparticular electrode, its density of traps are the hindering effects in the charge transport. In this study, crack-free TiO2 nanotube membranes, which obtained through a re-anodizing process, are fixed on transparent fluorine–tin-oxide glass by applying a few drops of Titanium Isopropoxide without needing the TiO2 powder paste. Front-side illuminated dye sensitized solar cells fabricated by undoped, N-doped and blue TiO2 nanotube membranes are investigated. The electrical characteristics of TiO2 nanotube based dye sensitized solar cells are followed by theoretical analysis using simple one-diode model....
MMRO: A feature selection criterion for MR images based on alpha stable filter responses
, Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings ; 2011 ; 9781457715358 (ISBN) ; Fatemizadeh, E ; Sharif University of Technology
2011
Abstract
In feature-based image registration, feature selection and reduction methods play an important role in decreasing computational burden of these operations. In this paper, a new approach is introduced to reduce the dimension of extracted feature vectors of MR images. This approach is based on the selection of the maximum and minimum responses of the alpha stable filter for the MR images over the extracted features with different orientation in frequency domain. This algorithm selects the rotation invariant features which are suitable for image registration purposes. It has been shown that these features could efficiently describe the image elements. The discriminating ability of the features...
Seismic hazard assessment for two cities in Eastern Iran
, Article Earthquake and Structures ; Volume 8, Issue 3 , 2015 , Pages 681-697 ; 20927614 (ISSN) ; Kamali Asl, A ; Sharif University of Technology
Techno Press
2015
Abstract
Iran as one of the countries located on the Alpine-Himalayan seismic belt has recently experienced a few number of catastrophic earthquakes. A well-known index of how buildings are affected by earthquakes is through assessment of probable Peak Ground Acceleration (PGA) and structures' response spectra. In this research, active faults around Kerman and Birjand, two major cities in eastern parts of Iran, have been considered. Seismic catalogues are gathered to categorize effects of surrounding faults on seismicity of the region. These catalogues were further refined with respect to time and space based on Knopoff-Gardner algorithm in order to increase statistical independency of events....
Analysis of Interlaminar Stresses in Boundary Layer of Circumferentially Closed Laminated Cylinders
,
M.Sc. Thesis
Sharif University of Technology
;
Noseir, Asghar
(Supervisor)
Abstract
In this study, using Reddy's layer-wise theory, thermal and rotational inter-laminar stress distribution within cylindrical composite shells with different boundary conditions is analytically studied. Convergence of the layer-wise theory is also studied and the numbers of sub-layers are determined so that efficient and accurate results can be achieved by this method. In order to assess the validity of layer-wise theory, results of this method are compared with results obtained by elasticity theory, for two sets of boundary conditions. It is observed that depending on the shell layer stacking, loading and boundary condition type, each of inter-laminar stresses may be the critical stress...
Hygrothermal Stress Analysis in Composite Laminatesby Perturbation Method
, M.Sc. Thesis Sharif University of Technology ; Nosier, Asghar (Supervisor)
Abstract
For studying the hygrothermal deformation of generally laminated composite platesunder uniform temperature change and uniform moisture absorption change, by starting from the reduced form of elasticity displacement field for a long flat laminate, an analytical method is developed in order to accurately calculate the interlaminar stresses near the free edges of the laminate. The constant parameters appearing in the reduced displacement field, describe the global deformation of the laminate and appropriately obtained by employing an improved first-order shear deformation theory.For solving the coupled equilibrium equations of agenerally laminated composite plate, some of the stiffness...
Nonlinear Forced Vibrations of Thin Circular and Elliptical Functionally Graded Plates
, M.Sc. Thesis Sharif University of Technology ; Nosier, Asghar (Supervisor)
Abstract
Nonlinear forced vibrations of thin functionally graded circular and elliptical plates under classical boundary conditions are investigated based on the classical plate theory. The von Kármán strain-displacement relations is employed to include geometrical nonlinearity caused by large transverse displacements of the plate thickness order, and modal expansion in polar and elliptical coordinate along with the perturbation method of multiple scale is used to solve the governing equations. The material properties are graded through the plate thickness according to a power-law distribution of the volume fraction of the constituents. Transverse forcing is supposed to be harmonic with angular...
Nonlinear Analysis of FG Rectangular Plates under Mechanical and Thermo-Mechanical Loads using the Extended Kantorovich Method
, M.Sc. Thesis Sharif University of Technology ; Nasier, Asghar (Supervisor)
Abstract
The purpose of this research is to provide an analytical solution using first order shear deformation theory for nonlinear bending of rectangular FG plate under mechanical and thermal loads with different boundary conditions. To achieve this goal, extended Kantorovich method have been used. This method has a high convergence rate and is more accurate than other approximate methods, such as the Ritz and Galerkin methods, because the partially differential equations are converted to ordinary differential equations. In order to solving nonlinear odes the perturbation method is used. Material of the plate is a mixture of ceramic and metal and is modeled as an isotropic and non-homogeneous...
Integration of the inertial navigation system with consecutive images of a camera by relative position and attitude updating
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 233, Issue 15 , 2019 , Pages 5592-5605 ; 09544100 (ISSN) ; Dehghani Firouzabadi, A ; Sharif University of Technology
SAGE Publications Ltd
2019
Abstract
This paper introduces a new method for improving the inertial navigation system errors using information provided by the camera. An unscented Kalman filter is used for integrating the inertial measurement unit data with the features’ constraints extracted from the camera’s image. The constraints, in our approach, comprise epipolar geometry of two consecutive images with more than 65% coverage. Tracking down a known feature in two consecutive images results in emergence of stochastic epipolar constraint. It emerges in the form of an implicit measurement equation of the Kalman filter. Correctly matching features of the two images is necessary for reducing the navigation system errors because...
Synthesis, characterization and fluorescence spectra of mixed ligand Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand
, Article Journal of Coordination Chemistry ; Volume 60, Issue 15 , 2007 , Pages 1629-1635 ; 00958972 (ISSN) ; Behzadian Asl , F ; Sharif University of Technology
2007
Abstract
The novel mixed ligand complexes [M(bpy)(phen-dione)](PF6)2 (M = Zn(II), Cd(II) and Hg(II), bpy = 2,2′-bipyridine and phen-dione = 1,10-phenanthroline-5,6-dione) have been synthesized and characterized by elemental analysis, IR, 1H NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione in these complexes are very similar to the free phen-dione ligand showing that phen-dione is not coordinated to metal ion from its C=O sites. Absorption spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence to the dielectric constant of solvent. These complexes exhibit an intensive fluorescence band around 535 nm in...
Synthesis, characterization and fluorescence spectra of mononuclear Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand
, Article Journal of Coordination Chemistry ; Volume 60, Issue 3 , 2007 , Pages 347-353 ; 00958972 (ISSN) ; Behzadian Asl, F ; Sharif University of Technology
2007
Abstract
The mononuclear complexes of Zn(II), Cd(II) and Hg(II), [Zn(phen-dione)Cl2], [Cd(phen-dione)Cl2] and [Hg(phen-dione)Cl2], where phen-dione = 1,10-phenanthroline-5,6-dione, have been synthesized and characterized by elemental analysis and IR, 1H NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione ligands in these complexes shows that the phen-dione is not coordinated to metal ion from its C=O sites. Electronic spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence on the dielectric constant of solvents. These complexes exhibit an intense fluorescence band around 545 nm in DMSO when the excitation...
An adaptive unscented Kalman filter for quaternion-based orientation estimation in low-cost AHRS
, Article Aircraft Engineering and Aerospace Technology ; 2007 , Pages 485-493 ; 00022667 (ISSN) ; Volume 79, Issue 5 ; Ghanbarpour Asl, H ; Sharif University of Technology
2007
Abstract
Purpose - This paper aims to develop an adaptive unscented Kalman filter (AUKF) formulation for orientation estimation of aircraft and UAV utilizing low-cost attitude and heading reference systems (AHRS). Design/methodology/approach - A recursive least-square algorithm with exponential age weighting in time is utilized for estimation of the unknown inputs. The proposed AUKF tunes its measurement covariance to yield optimal performance. Owing to nonlinear nature of the dynamic model as well as the measurement equations, an unscented Kalman filter (UKF) is chosen against the extended Kalman filter, due to its better performance characteristics. The unscented transformation of the UKF is shown...