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mahabadi-mohamadi--mohamad
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Improving Robustness of Deep Neural Networks Against Adversarial Examples in Image
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
Despite widespread applications and high performance of deep neural networks in the fields of computer vision, they have been shown to be vulnerable to adversarial examples. An adversarial example is a perturbated image that the magnitude of its difference with its corresponding natural image is small and yet given such example, the network produces incorrect output. In recent years, many approaches have been proposed to increase the robustness of DNNs against adversarial examples with adversarial training being proposed as the most effective defense measure. Approaches based on adversarial training try to increase the robustness of the network by training on the adversarial examples. One of...
Investigation of Seismic Response of Circular-Plan Concrete Funicular Shells
, M.Sc. Thesis Sharif University of Technology ;
Abstract
The present study considers the performance of circular-plan concrete funicular shells due to seismic loads for simply boundary conditions. Vibration frequencies of these shells along with their seismic responses included displacement and stresses generated in them due to the acceleration components of Tabas and Manjil earthquakes are determined via the use Abaqus software. Frequencies of vibration determined with software are compared with the results of a semi-analytical model where good agreement is achieved.The results of the performed analyses for vibration frequencies show that both of the reduction of the base diameter and the incerese of the rise increase the frequencies of...
Common Areas of Language Impairment in Persian-speaking Autistic Children
, M.Sc. Thesis Sharif University of Technology ; Khosravizadeh, Parvaneh (Supervisor)
Abstract
In qualitative content analysis research with the aim of identifying areas of language impairmenthigh-functioning Persian-speaking autistic children, ten subjects were observed during fifteen training sessions which were the cognitive block of a three-block training program. Each session lasted 90 minutes and was video recorded. Prior to this, focus group interviews with specialists and semi-structured interviews with mothers and parallel to that focus group interviews with mothers were handled all of which were audio recorded. After two levels of initial and second coding, a final list of areas of impairment in the language of high-functioning Persian-speaking autistic children, that...
Investigating the Behaviour of Some Kind of Fibre-reinforced Concrete
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
While there are many advantages associated with concrete, including high compressive strength, durability and so forth, on the contrary, it has several disadvantages which may make engineers somewhat reluctant to use it. These include low tensile strength, high brittleness, low resistance to impact, large dimensions of structural cross sections, etc. In recent years, there have been many attempts to surmount these disadvantages by various means such as adding pozzolans, using FRPs, fibres, etc. In this project, the effects of using a special type of high strength steel fibre is studied. In order to investigate the effect of this fibre on the compressive behavior of concrete, 30 cylindrical...
Developing a Simulator for Concurrent Execution of Multiple Workflows in Fog Computing Environment
, M.Sc. Thesis Sharif University of Technology ; Izadi, Mohamad (Supervisor)
Abstract
Fog computing environment consists of several devices which distribute across an arbitrary topology. Each of these devices is capable of carrying out a designated computation simultaneously with other devices. One of the common ways of describing a computation is through the usage of workflows. Workflow is a flexible and formal way of modeling tasks and their requirements for execution. A workflow is essentially a DAG. Therefore, it can model the data dependency between tasks quite accurately. The complex structure of a workflow in conjunction with the homogenous nature of devices in a fog environment makes it difficult to find a resource management algorithm to minimize execution time, used...
Investigation of the Drop Tank Influence on Range and Optimization of Its Geometry
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohamad (Supervisor)
Abstract
This project focuses on the design of fuel drop tanks for airplanes that add minimal drag and positive lift to the flying object. This will obviously effect the stability and dynamic performance of the airplane. To reduce adverse dynamic effects the tank was divided to several segment with a special emptying sequence. The add-on tank has to have no interference with the object existing systems and require minimum structural changes in the object. Several designs were proposed and the one gaining highest marks was selected. The flow field and the dynamic behavior of combined vehicle and drop tanks were studied using FE simulations. The result shows that adding a drop tank with optimized...
Introducing a dimensionless number as tank selector in hybrid solar thermal energy storage systems
, Article Evolutionary Ecology ; Volume 25, Issue 4 , 2011 , Pages 871-876 ; 02697653 (ISSN) ; Zohoor, H ; Sharif University of Technology
2011
Abstract
Using hybrid energy storage system is a method for increasing the storage capability of solar thermal energy. If multiple energy storage devices with complementary performance characteristics are used together, the resulting system will be a 'Hybrid Energy Storage System'. In other words, a Hybrid Energy Storage System (HESS) has several media available for storage at any time. In this way, increase in storable energy is obtained without increasing collectors' area. When there are more than one storage mediums, the system should be able to choose the best medium for storing energy according to the conditions. In the previous works, an optimizer program was used to find the proper medium...
Introducing a dimensionless number as tank selector in hybrid solar thermal energy storage systems
, Article Journal of Mechanical Science and Technology ; Volume 25, Issue 4 , 2011 , Pages 871-876 ; 1738494X (ISSN) ; Zohoor, H ; Sharif University of Technology
2011
Abstract
Using hybrid energy storage system is a method for increasing the storage capability of solar thermal energy. If multiple energy storage devices with complementary performance characteristics are used together, the resulting system will be a 'Hybrid Energy Storage System'. In other words, a Hybrid Energy Storage System (HESS) has several media available for storage at any time. In this way, increase in storable energy is obtained without increasing collectors' area. When there are more than one storage mediums, the system should be able to choose the best medium for storing energy according to the conditions. In the previous works, an optimizer program was used to find the proper medium...
An embedded elliptic nano-fiber in anti-plane strain couple stress elasticity
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 13, Issue PART A , 2009 , Pages 145-152 ; 9780791848746 (ISBN) ; Haftbaradaran, H ; Sharif University of Technology
2009
Abstract
The application of higher order continuum theories, with size effect considerations, have recently been spread in the micro and nano-scale studies. One famous version of these theories is the couple stress theory. This paper utilizes this theory to study the anti-plane problem of an elliptic nano-fiber, embedded in an infinite medium, both made of centrosymmetric isotropic material. In this framework, a characteristic length appears in the formulation, by which examination of the size effect is possible. This work presents an analytical solution for the proposed problem. Copyright © 2008 by ASME
A numerical solution of 2D Buckley-Leverett equation via gradient reproducing kernel particle method
, Article CMES - Computer Modeling in Engineering and Sciences ; Volume 32, Issue 1 , 2008 , Pages 17-33 ; 15261492 (ISSN) ; Hashemian, A ; Sharif University of Technology
2008
Abstract
Gradient reproducing kernel particle method (GRKPM) is a meshless technique which incorporates the first gradients of the function into the reproducing equation of RKPM. Therefore, in two-dimensional space GRKPM introduces three types of shape functions rather than one. The robustness of GRKPM's shape functions is established by reconstruction of a third-order polynomial. To enforce the essential boundary conditions (EBCs), GRKPM's shape functions are modified by transformation technique. By utilizing the modified shape functions, the weak form of the nonlinear evolutionary Buckley-Leverett (BL) equation is discretized in space, rendering a system of nonlinear ordinary differential equations...
Parallel Lagrange interpolation on k-ary n-cubes with maximum channel utilization
, Article Journal of Supercomputing ; Volume 46, Issue 1 , 2008 , Pages 1-14 ; 09208542 (ISSN) ; Sarbazi Azad, H ; Khodaie, E ; Navi, K ; Sharif University of Technology
2008
Abstract
This paper proposes an efficient parallel algorithm for computing Lagrange interpolation on k-ary n-cube networks. This is done using the fact that a k-ary n-cube can be decomposed into n link-disjoint Hamiltonian cycles. Using these n link-disjoint cycles, we interpolate Lagrange polynomial using full bandwidth of the employed network. Communication in the main phase of the algorithm is based on an all-to-all broadcast algorithm on the n link-disjoint Hamiltonian cycles exploiting all network channels, and thus, resulting in high-efficiency in using network resources. A performance evaluation of the proposed algorithm reveals an optimum speedup for a typical range of system parameters used...
Multifunctional hyperelastic structured surface for tunable and switchable transparency
, Article Applied Sciences (Switzerland) ; Volume 11, Issue 5 , 2021 , Pages 1-11 ; 20763417 (ISSN) ; Goudarzi, T ; Fleury, R ; Naghdabadi, R ; Sharif University of Technology
MDPI AG
2021
Abstract
We leverage the crucial hyperelastic properties of a multifunctional structured surface to optimize the reconfigurability of the electromagnetic transmission under large nonlinear mechanical deformations. This multiphysics, multifunctional, hyperelastic structured surface (HSS) offers two simultaneous intriguing functionalities; tunability and switchability. It is made of copper reso-nators and a Polydimethylsiloxane (PDMS) substrate, which is one of the most favorable deformable substrates due to its hyperelastic behavior. The proposed HSS is fabricated via an original cost-effective technique and the multiphysics functionalities are captured in both experimental tests and numerical...
Spectroscopic Study and Characterizing of Selenium Dioxide Complex with Pyridoxine(PN-Se):Interaction Between (PN-Se)and Bovine Serum Albumin
, M.Sc. Thesis Sharif University of Technology ; Mohamadi Boghaei, Davar (Supervisor)
Abstract
Temporary existence of some molecules like medicines in body and also existence of diagnostic agents in biological systems and study of the interactions of biomolecules with these agents is a matter of interest. It also may have an important role in design and synthesis of new drugs. Serum Albumin is the most abundant protein in circulation system in the body. So far, many studies about the interaction of this protein with different compounds have been undertaken. The aim of this paper was to synthesize selenium complex and analyze its potential biochemical activity in vitro. The concrete work falls into two parts:(1) to synthesize the selenium-pyridoxine compound (PNSe) (2) to probe into...
New modeling for moment-rotation behavior of bolted endplate connections
, Article Scientia Iranica ; Volume 18, Issue 4 A , August , 2011 , Pages 827-834 ; 10263098 (ISSN) ; Mofid, M ; Sharif University of Technology
2011
Abstract
A new exponential model to depict the moment-rotation (M-θ) relationship of Bolted Endplate Connections (BEC) is proposed. The proposed model represents an approach to the prediction of M-O curves, taking into account the possible failure modes and the deformation characteristics of the connection elements. The presented model has three physical parameters, along with two curve-fitted factors. These physical parameters are generated from dimensional details of the connection, as well as the material properties. By employing simplified connection behavioral models to estimate the connection M-θ behavior, analytical expressions for evaluating major connection parameters, such as initial...
Prediction of the yielding moment of flush endplate splice connections using finite element modeling
, Article Scientia Iranica ; Volume 20, Issue 2 , 2013 , Pages 270-277 ; 10263098 (ISSN) ; Mofid, M ; Sharif University of Technology
2013
Abstract
This paper presents the results of parametric analyses of the yielding moment (My) of Bolted Flush Endplate Beam (BFEB) splice connections using Finite Element Modeling (FEM) tools. The connection components were modeled using three-dimensional brick elements, while contact between the endplates was modeled using Coulomb friction. Materials for beam, endplate and bolts were considered to behave non-linearly. Finite element results with three experimental and numerical studies were compared, and all indicated good agreement, which is also briefly reviewed in this paper. Using verified FEM, fairly large parametric studies, based on the practical configuration of BFEB connections, were carried...
Corrigendum to: "parametric analyses on the initial stiffness of flush end-plate splice connections using FEM" [J. construct. steel res. 64 (2008) 1129-1141] (DOI:10.1016/j.jcsr.2007.09.010)
, Article Journal of Constructional Steel Research ; Volume 65, Issue 3 , 2009 , Pages 749- ; 0143974X (ISSN) ; Mofid, M ; Sharif University of Technology
2009
Intrusion detection in computer networks using tabu search based Fuzzy system
, Article 2008 7th IEEE International Conference on Cybernetic Intelligent Systems, CIS 2008, London, 9 September 2008 through 10 September 2008 ; March , 2008 ; 9781424429141 (ISBN) ; Habibi, J ; Saadi, H ; Sharif University of Technology
2008
Abstract
The process of scanning the events occurring in a computer system or network and analyzing them for warning of intrusions is known as intrusion detection system (IDS). This paper presents a new intrusion detection system based on tabu search based fuzzy system. Here, we use tabu search algorithm to effectively explore and exploit the large state space associated with intrusion detection as a complicated classification problem. Experiments were performed on KDD-Cup99 data set which has information about intrusive and normal behaviors on computer networks. Results show that the proposed method obtains notable accuracy and lower cost in comparison with several renowned algorithms
Parametric analyses on the initial stiffness of flush end-plate splice connections using FEM
, Article Journal of Constructional Steel Research ; Volume 64, Issue 10 , 2008 , Pages 1129-1141 ; 0143974X (ISSN) ; Mofid, M ; Sharif University of Technology
Elsevier BV
2008
Abstract
Existing design procedures for steel frames have been modified during the last three decades to incorporate the semi-rigid behavior of the connections into the frame design advancement. Knowledge in initial rotational stiffness of a connection is important for the global elastic analysis of frame structures. This paper presents the results of several parametric analyses on the Initial Rotational Stiffness (IRS or Sini) of Bolted Flush End-plate Beam (BFEB) splice connections using Finite Element Modeling (FEM). The FEMs have taken into account material behavior, geometrical discontinuities and large displacements. The analyses have been calibrated to experimental results that are also...
A combinational adaptive noise canceller using filter bank
, Article 6th International Symposium on Image and Signal Processing and Analysis, ISPA 2009, Salzburg, 16 September 2009 through 18 September 2009 ; 2009 , Pages 71-74 ; 9789531841351 (ISBN) ; Hejazi, A ; Akhaee, M. A ; Eshghi, M ; Sharif University of Technology
2009
Abstract
This paper proposes a novel combinational Adaptive Noise Canceller (ANC), which is suitable for non stationary noise environments. Pre-filter bank structure improves the convergence rate leading to less error in real-time applications. During our investigations, we have found out adaptive algorithms have better performance for low frequency subbands. Thus, by using Singular Value Decomposition (SVD) in each subband, a simplified version of variable step-size algorithms has been employed in low frequency subbands; while for high frequency subbands, some conventional techniques have been used. Simulation results show that combination of adaptive and conventional methods have better performance...
A Stochastic Model for Cancer Tumor Growth
, M.Sc. Thesis Sharif University of Technology ; Foroughmand Arabi, Mohamad Hadi (Supervisor) ; Alishahi, Kasra (Co-Supervisor)
Abstract
Cancer can be defined as a stochastic phenomenon. Thus, the tumor growth can be defined as a stochastic process. A Cancer tumor can be analyzed by its geometric shape. Furthermore, computing fractal dimension of shapes is a useful technique to analyze chaosity and complexity of shapes. This approach can be used to compare results from laboratory with simulated results of a mathematical model. A stochastic model of tumor growth will be presented. And some geometrical properties will be analyzed through computer simulation of the model