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    Investigating the Behaviour of Some Kind of Fibre-reinforced Concrete

    , M.Sc. Thesis Sharif University of Technology Alaei Mahabadi, Alireza (Author) ; 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... 

    A Game Theoretic Inventory Model for a Two-Echelon Supply Chain with Poisson Demand

    , M.Sc. Thesis Sharif University of Technology Alaei, Saeed (Author) ; Hajji, Alireza (Supervisor)
    Abstract
    In this research, we study the differences between the centralized and decentralized approaches in a two-stage serial supply chain including a manufacturer and a retailer under the lost sale policy. The centralized approach results in optimal solution of the system and the decentralized one is based on Stackelberg game in which the manufacturer is the leader. The retailer uses the continuous review (r, Q) policy and the demand arrives according to the stationary Poisson process. In order to obtain the solution for two approaches, a set of computational steps are developed. Furthermore, we provide a numerical example and the corresponding sensitivity analysis to compare the two approaches.... 

    A theoretical game approach for two- echelon stochastic inventory system

    , Article Acta Polytechnica Hungarica ; Volume 12, Issue 4 , 2015 , Pages 221-239 ; 17858860 (ISSN) Alaei, S ; Hajji, A ; Alaei, R ; Behravesh, M ; Sharif University of Technology
    Budapest Tech Polytechnical Institution  2015
    Abstract
    In this paper, we study the differences between the Centralized and Decentralized approaches in a two-echelon stochastic inventory system under the lost sale policy. We formulate the condition in which the retailer applies (r, Q) inventory policy, and his relation with the upper echelon who acts as a manufacturer. This situation has not been considered in the literature before. The Centralized approach results in optimal solution of the system and the Decentralized one is based on Stackelberg game in which the manufacturer is the leader. The demand arrives according to the stationary Poisson process. We drive the long-run average cost functions, then a set of computational steps are... 

    Common Areas of Language Impairment in Persian-speaking Autistic Children

    , M.Sc. Thesis Sharif University of Technology Mahabadi, Sara (Author) ; 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... 

    Fermi surface nesting and possibility of orbital ordering in FeO

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 374, Issue 36 , August , 2010 , Pages 3793-3796 ; 03759601 (ISSN) Alaei, M ; Jafari, S. A ; Sharif University of Technology
    2010
    Abstract
    Remarkable inter-band nesting in FeO Fermi surface, hints to examine energy of orbitally ordered states, which turn out to be more stable. We propose this method as a general scheme to check for possibility of orbital ordering in first principle calculations, and demonstrate it for known examples, LiVO2 and LaMnO3  

    Improving Robustness of Deep Neural Networks Against Adversarial Examples in Image

    , M.Sc. Thesis Sharif University of Technology Mahabadi Mohamadi, Mohamad (Author) ; 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... 

    Evaluation of marketing-pricing decisions in a two-echelon supply chain

    , Article Engineering Economics ; Volume 24, Issue 2 , 2013 , Pages 135-143 ; 13922785 (ISSN) Alaei, S ; Behravesh, M ; Karegar, N ; Sharif University of Technology
    Kauno Technologijos Universitetas  2013
    Abstract
    This paper discusses the interaction between one manufacturer and a single retailer in a channel in which both are willing to optimize their profit by adjusting pricing and advertising decisions. The manufacturer produces and sells a product at wholesale price to the retailer who in turn distributes it to consumers with retail price. The market demand is simultaneously affected by retail price, brand advertising of the manufacturer, and local advertising of the retailer. A Cobb-Douglas demand function is used to demonstrate the relationship between the parameters. Decision variables are two firms’ prices and their advertising investments. The problem is modelled under integrated policy and... 

    Skiptree: a new scalable distributed data structure on multidimensional data supporting range-queries

    , Article Computer Communications ; Volume 33, Issue 1 , 2010 , Pages 73-82 ; 01403664 (ISSN) Alaei, S ; Ghodsi, M ; Toossi, M ; Sharif University of Technology
    2010
    Abstract
    This paper presents a new balanced, distributed data structure for storing data with multidimensional keys in a peer-to-peer network. It supports range queries as well as single point queries which are routed in O (log n) hops. Our structure, called SkipTree, is fully decentralized with each node being connected to O (log n) other nodes. We propose modifications to the structures, so that the memory usage for maintaining the link structure at each node is reduced from the worst case of O (n) to O (log n log log n) on the average and O (log2 n) in the worst case. It is also shown that the load balancing is guaranteed to be within a constant factor. Our experimental results verify our... 

    The relative importance of the business model motive for customer participation in the sharing economy

    , Article Sustainable Production and Consumption ; Volume 34 , 2022 , Pages 190-201 ; 23525509 (ISSN) Alaei, S ; Aslani, S ; Talebian, M ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    The sharing economy, defined by peer-to-peer interactions through a platform, has been gaining ground in recent years. In this study, we discuss the relative importance of customers' perceived motives to participate in the two most common models of the sharing economy: access-based consumption and ownership-transfer. We focus on taxi-hailing and post-delivery as examples of access-based consumption and second-hand trade as an example of the ownership-transfer. While these two contain heterogeneous business model patterns that can motivate customers differently, common motives are significant in both models. We study common motives and motives aligned with the business model patterns, which... 

    SkipTree: A Scalable range-queryable distributed data structure for multidimensional data

    , Article 16th International Symposium on Algorithms and Computation, ISAAC 2005, Hainan, 19 December 2005 through 21 December 2005 ; Volume 3827 LNCS , 2005 , Pages 298-307 ; 03029743 (ISSN); 3540309357 (ISBN); 9783540309352 (ISBN) Alaei, S ; Toossi, M ; Ghodsi, M ; Sharif University of Technology
    2005
    Abstract
    This paper presents the SkipTree, a new balanced, distributed data structure for storing data with multidimensional keys in a peer-to-peer network. The SkipTree supports range queries as well as single point queries which are routed in O(log n) hops. SkipTree is fully decentralized with each node being connected to O(logn) other nodes. The memory usage for maintaining the links at each node is O(log n log log n) on average and O(log2 n) in the worst case. Load balance is also guaranteed to be within a constant factor. © Springer-Verlag Berlin Heidelberg 2005  

    Exploring cognitive activation writing strategies among iranian english language teachers

    , Article Language Related Research ; Volume 12, Issue 5 , 2021 , Pages 433-462 ; 23223081 (ISSN) Alaei, M. M ; Hassanzadeh, M ; Masoudi, M ; Sharif University of Technology
    Tarbiat Modares University  2021
    Abstract
    In order to engage students in higher-level thinking, cognitive activation (CA) strategies have been advanced and utilized in mathematics. CA develops when learners are challenged, confronted with conflicts, asked to think and explain clearly on their learning, and realize connections between new and previous content. Extending the theme to English language teaching (ELT), this study investigated Iranian English language teachers‟ knowledge and practice of cognitive activation writing strategies (CAWS). In so doing, a model was proposed based on a questionnaire that was developed and validated in the present study. Through this scale, knowledge and practice of CAWS by 213 English as a... 

    Exploring cognitive activation writing strategies among iranian english language teachers

    , Article Language Related Research ; Volume 12, Issue 5 , 2021 , Pages 433-462 ; 23223081 (ISSN) Mostafaei Alaei, M ; Hassanzadeh, M ; Masoudi, M ; Sharif University of Technology
    Tarbiat Modares University  2021
    Abstract
    In order to engage students in higher-level thinking, cognitive activation (CA) strategies have been advanced and utilized in mathematics. CA develops when learners are challenged, confronted with conflicts, asked to think and explain clearly on their learning, and realize connections between new and previous content. Extending the theme to English language teaching (ELT), this study investigated Iranian English language teachers‟ knowledge and practice of cognitive activation writing strategies (CAWS). In so doing, a model was proposed based on a questionnaire that was developed and validated in the present study. Through this scale, knowledge and practice of CAWS by 213 English as a... 

    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) Mahabadi, A ; 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) Mahabadi, R. K ; 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... 

    Human Genome Sequence Analysis Using Statistical and Machine Learning Methods

    , M.Sc. Thesis Sharif University of Technology Alaei, Shervin (Author) ; Manzuri Shalmani, Mohammad Taghi (Supervisor)
    Abstract
    During recent decades, dramatic advances in Genetics and Molecular Biology, has provided scientists with enormous amounts of molecular genomic information of different living organisms, from DNA sequences to complex 3d structures of proteins. This information is raw data which their analysis can provide better understanding of genome mechanisms, discriminating healthy and tumor cells, predicting disease type, making drugs based on genome information, and many more applications. Here, one important issue is the inevitable use of computer science and statistics to analyze these data; such that according to the vast amount of data, would provide intelligent methods, which yield most accurate... 

    Study of Customers’ Motivations and the Impact of Touchpoints on Motives to Use Different Industries of the Sharing Economy

    , M.Sc. Thesis Sharif University of Technology Alaei, Saedeh (Author) ; Talebian, Masoud (Supervisor) ; Aslani, Shirin (Supervisor)
    Abstract
    With the rise of the sharing economy, customers’ motivations to participate has become a controversial phenomenon. The sharing economy has different industries that might itself be a reason for the emergence of different incentives in customers. Moreover, these industries can affect motivation by controlling various touchpoints Two dimensions, quantity and quality illustrate the impact of touchpoints The encounter of touchpoints with both of the provider and consumer side might confuse companies to choose the best composition of has been conducted to identify the importance of motives to use different industries of the sharing economy and examine the impact of the brands’ touchpoints . In... 

    A Machine Learning Simulator for Task Offloading and Resource Allocation in IoV

    , M.Sc. Thesis Sharif University of Technology Alaei Tabatabaei, Ali (Author) ; Bayat Sarmadi, Siavash (Supervisor)
    Abstract
    Recent years have witnessed significant advancements in the smart transportation industry. Timely execution of processes and tasks prior to deadlines is crucial and sensitive. With the advancement of the automotive industry and smart transportation vehicles, the number of smart vehicles is increasing day by day. However, not all devices can perform their respective tasks on time, hence the need for edge network servers to assist in task execution .Decision-making regarding task execution methods and resource allocation in mobile networks poses a significant challenge. In recent research, given the complexity of the issue and the advancements in machine learning algorithms, the efficacy of... 

    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) Ameri Mahabadi, A ; 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... 

    Study on Structure, Mechanical Properties, and Flammability of PC/ABS

    , M.Sc. Thesis Sharif University of Technology Alaei, Yasaman (Author) ; Bagheri, Reza (Supervisor) ; Seyed Reyhani, Morteza (Supervisor)
    Abstract
    Polycarbonate (PC) is known as one of the engineering plastics with remarkable mechanical properties, but the application of this polymer is limited due to its high notch sensitivity. Blending polycarbonate with other polymers such as acrylonitrile butadiene styrene (ABS) is a method to resolve this disadvantage. PC/ABS blends are commonly used in automotive industry, electrical and electronic devices. As PC and ABS are not completely miscible, a variety of compatibilizers are used to achieve a suitable microstructure and high engineering properties. Considering crucial applications of PC/ABS blends, different flame retardants are also used to reduce the flammability. These flame retardants... 

    Effects of resonator geometry and substrate stiffness on the tunability of a deformable microwave metasurface

    , Article AEU - International Journal of Electronics and Communications ; Volume 146 , 2022 ; 14348411 (ISSN) Karimi Mahabadi, R ; Goudarzi, T ; Fleury, R ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
    Elsevier GmbH  2022
    Abstract
    Tunable metasurfaces can shift their resonant frequency through different approaches, one of which is applying mechanical deformations. Here, we show the effects of two key factors on the tunability of deformable metasurfaces; the resonator geometry and substrate stiffness. To show the effects, we compared the tunability of unit cells with three resonator geometries and three common substrates at microwave frequencies from 1 GHz to 10 GHz under a given mechanical deformation. We showed that the resonator geometry affects the deformation field, as a consequence, causes different resonant frequency shifts. Moreover, it affects the stress field in the metasurface which in turn limits the...