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    An Introduction to Langlands Program

    , M.Sc. Thesis Sharif University of Technology Hatami Varzaneh, Omid (Author) ; Pournaki, Mohammadreza (Supervisor)
    Abstract
    The Weil group WF is assigne to every local field F. Langlands Correspondence is a bijetion between semisimple two-dimensional Deligne representations of Weil Group WF and irreducible representations of GL2(F) which fixes assigned L-functions and local constants. In this thesis we have classified an important class of irreducible representations of GL(2) over local fields called Principal Series. We also tried to give a taste of Langlands Correspondence to the reader. First we explain preliminaries and introduce locally profinite groups and their smooth representations. Then we classify representations of GL2(F) when F is finite. Then we study GL2(F) when F is a local field. Finally we... 

    Approximation Algorithms for Clustering Points in the Data Stream Model

    , M.Sc. Thesis Sharif University of Technology Hatami Varzaneh, Behnam (Author) ; Zarrabi Zadeh, Hamid (Supervisor)
    Abstract
    The k-center problem—covering a set of points using k congruent balls with minimum radius—is a well-known clustering model in computer science with a wide range of applications. The k-center is a well known NP-Hard problem. In this thesis, we focus on the k-center problem with outliers in high dimensional data streams. Due to increase in data size, we focus on the data stream model of the problem. Moreover, in real-world applications, where input points are noisy, it is very important to consider outliers. In this thesis, we study 1-center and 2-center with outliers in high dimensional data streams in Euclidean space. We provide a 1:7-approximation streaming algorithm for 1-center with z... 

    Existence of Arithmetic Progressions in Subsets of Natural Numbers

    , M.Sc. Thesis Sharif University of Technology Zareh Bidaki, Mojtaba (Author) ; Rastegar, Arash (Supervisor) ; Hatami Varzaneh, Omid (Supervisor)
    Abstract
    Szemeredi's theorem is one of the significant theorems in additive combinatorics which was started by Van Der Waerden's theorem in 1927. Erdos and Turan conjectured generalized versions of Van Der Waerden's theorem in several ways included Szemeredi's theorem. In 1975 Szemeredi proved the conjecture using complicated combinatorial methods. In 1977 H. Furstenberg proved Szemeredi's theorem via the Ergodic theory approach which led to prove polynomial Szemeredi's theorem and multi-dimensional Szemeredi's theorem. The Ergodic approach is the only known approach so far to these generalizations of this theorem which is named Ergodic Ramsey theory and led to some other problems in Ergodic theory... 

    A comprehensive architecture platform for smarter universities

    , Article 2023 28th International Computer Conference, Computer Society of Iran, CSICC 2023 ; 2023 ; 979-835033819-5 (ISBN) Saberi Varzaneh, A ; Merikhi, B ; Saberi Varzaneh, M ; Alam Varzaneh Isfahani, M. H ; Habibi Kalahroodi, H ; Fatemipour Sharabiany, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2023
    Abstract
    One of the most crucial infrastructure requirements of integrated systems is designing and providing a comprehensive architecture for implementation, support and improvement of their smart services or platforms. And without exception, smart University would also require a responsive architecture for the integration and consolidation of its current and future systems and services. Providing higher level of academic services, integration and consolidation support, and cost accounting (including 'cloud storage', 'computing', 'network communication and bandwidth' and energy consumption) can be placed as pivotal issues among smart university services. In this article, a basic definition of a... 

    Correction to: Oseledets Splitting and Invariant Manifolds on Fields of Banach Spaces (Journal of Dynamics and Differential Equations, (2021), 10.1007/s10884-021-09969-1)

    , Article Journal of Dynamics and Differential Equations ; 2021 ; 10407294 (ISSN) Ghani Varzaneh, M ; Riedel, S ; Sharif University of Technology
    Springer  2021
    Abstract
    The original version of this article unfortunately contained a typo in co-author name. The author name is “Mazyar Ghani Varzaneh” instead it was published incorrectly as “M. Mazyar Ghani Varzaneh”. © 2021, Springer Science+Business Media, LLC, part of Springer Nature  

    Oseledets splitting and invariant manifolds on fields of banach spaces

    , Article Journal of Dynamics and Differential Equations ; Volume 35, Issue 1 , 2023 , Pages 103-133 ; 10407294 (ISSN) Ghani Varzaneh, M ; Riedel, S ; Sharif University of Technology
    Springer  2023
    Abstract
    We prove a semi-invertible Oseledets theorem for cocycles acting on measurable fields of Banach spaces, i.e. we only assume invertibility of the base, not of the operator. As an application, we prove an invariant manifold theorem for nonlinear cocycles acting on measurable fields of Banach spaces. © 2021, The Author(s)  

    Correction to: Oseledets splitting and invariant manifolds on fields of banach spaces (journal of dynamics and differential equations, (2023), 35, 1, (103-133), 10.1007/s10884-021-09969-1)

    , Article Journal of Dynamics and Differential Equations ; Volume 35, Issue 1 , 2023 , Pages 983- ; 10407294 (ISSN) Ghani Varzaneh, M ; Riedel, S ; Sharif University of Technology
    Springer  2023
    Abstract
    A correction to this paper has been published: https://doi.org/10.1007/s10884-021-09990-4 © 2021, Springer Science+Business Media, LLC, part of Springer Nature  

    Oseledets splitting and invariant manifolds on fields of banach spaces

    , Article Journal of Dynamics and Differential Equations ; 2021 ; 10407294 (ISSN) Ghani Varzaneh, M. M ; Riedel, S ; Sharif University of Technology
    Springer  2021
    Abstract
    We prove a semi-invertible Oseledets theorem for cocycles acting on measurable fields of Banach spaces, i.e. we only assume invertibility of the base, not of the operator. As an application, we prove an invariant manifold theorem for nonlinear cocycles acting on measurable fields of Banach spaces. © 2021, The Author(s)  

    The most optimal barrier height of InGaN light-emitting diodes

    , Article Applied Physics A: Materials Science and Processing ; Volume 127, Issue 2 , 2021 ; 09478396 (ISSN) Alam Varzaneh Isfahani, M. H ; Faez, R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    In this paper, a novel structure is presented in order to decrease the polarization charges of quantum wells. The main purpose of this design is to make electron and hole wavefunctions closer to each other and to increase overlap integral following an increase of radiative recombination rates and internal quantum efficiency. Furthermore, carriers will be increased and become more balanced and identical which leads to an increase in efficiency of light-emitting diodes. The improvement of radiative recombination rates is studied in new structures. Energy bands diagram, carriers density, current density–voltage, and power density–current density are used to demonstrate the superior performance... 

    The most optimal barrier height of InGaN light-emitting diodes

    , Article Applied Physics A: Materials Science and Processing ; Volume 127, Issue 2 , 2021 ; 09478396 (ISSN) Alam Varzaneh Isfahani, M. H ; Faez, R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    In this paper, a novel structure is presented in order to decrease the polarization charges of quantum wells. The main purpose of this design is to make electron and hole wavefunctions closer to each other and to increase overlap integral following an increase of radiative recombination rates and internal quantum efficiency. Furthermore, carriers will be increased and become more balanced and identical which leads to an increase in efficiency of light-emitting diodes. The improvement of radiative recombination rates is studied in new structures. Energy bands diagram, carriers density, current density–voltage, and power density–current density are used to demonstrate the superior performance... 

    A dynamical theory for singular stochastic delay differential equations i: linear equations and a multiplicative ergodic theorem on fields of banach spaces

    , Article SIAM Journal on Applied Dynamical Systems ; Volume 21, Issue 1 , 2022 , Pages 542-587 ; 15360040 (ISSN) Ghani Varzaneh, M ; Riedel, S ; Scheutzow, M ; Sharif University of Technology
    Society for Industrial and Applied Mathematics Publications  2022
    Abstract
    We investigate singular stochastic delay differential equations (SDDEs) in view of their long-time behavior. Using Lyons's rough path theory, we show that SDDEs can be solved pathwise and induce a continuous stochastic flow on the space of (Gubinelli's) controlled paths. In the language of random dynamical systems, this result shows that SDDEs induce a continuous cocycle on random fibers, or, more precisely, on a measurable field of Banach spaces. We furthermore prove a multiplicative ergodic theorem (MET) on measurable fields of Banach spaces that applies under significantly weaker structural and measurability assumptions than preceding METs. Applying it to linear SDDEs shows that the... 

    Simulation and Implementation of Active Energy Management Algorithm on Residential Photovoltaic System with Storage

    , M.Sc. Thesis Sharif University of Technology Ghafouri Varzaneh, Saeed (Author) ; Abbaspour, Ali (Supervisor)
    Abstract
    In majority of the (standalone or grid-connected) PV Systems, predefined rule-based algorithms are utilized in order to manage and control the flow of power. The function of these algorithms is to send the generated energy from solar panels either to load for consumption, or to battery for storage, or to the grid for sale. Their performance is based on predefined instructions and regardless of load change and consumption patterns. Therefore the total efficiency of these systems depend greately upon individual user’s load type and consumption pattern. In current research, an optimum and dynamic energy management algorithm is proposed using dynamic programming (DP) method, in order to increase... 

    Examination of a solar desalination system equipped with an air bubble column humidifier, evacuated tube collectors and thermosyphon heat pipes

    , Article Desalination ; Volume 397 , 2016 , Pages 30-37 ; 00119164 (ISSN) Behnam, P ; Behshad Shafii, M ; Sharif University of Technology
    Elsevier  2016
    Abstract
    In this paper, the performance of a novel HDH solar desalination system equipped with a combination of heat pipe (HP), evacuated tube collector (ETC) and air bubble column humidifier is experimentally investigated. This novel HDH system uses advantages of ETC-HP as a highly efficient thermal absorption and conductor device, and at the same time employs the advantages of an air bubble column humidifier, i.e. high interface area and effective mixing in order to heat the water and humidify the air, respectively. The effects of various parameters including incoming air flow rate into the humidifier, initial depth of water in the humidifier, and adding fluids such as oil and water in the space... 

    Dynamical Properties of Rough Delay Equations

    , Ph.D. Dissertation Sharif University of Technology Ghani Varzaneh, Mazyar (Author) ; Zohuri Zangeneh, Bijan (Supervisor)
    Abstract
    In this monograph, we investigate the long-time behavior of stochastic delay equations. Our approach is random dynamical systems, and we solve our equation in the rough path point of view. Namely, we deal with the singular case, i.e., when the delay terms also are appearing in the diffusion part. Although we can solve the equation using the classical tools of stochastic analysis, the main obstacle is the lack of flow property. More precisely, the solution does not depend continuously on the initial value. To solve this problem, we define this property differently. We will show how we can generate a flow property on fields of Banach spaces using rough path theory. As a consequence, we prove... 

    MRI-PET image fusion based on NSCT transform using local energy and local variance fusion rules

    , Article Journal of Medical Engineering and Technology ; Vol. 38, issue. 4 , 2014 , p. 211-219 Amini, N ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
    2014
    Abstract
    Image fusion means to integrate information from one image to another image. Medical images according to the nature of the images are divided into structural (such as CT and MRI) and functional (such as SPECT, PET). This article fused MRI and PET images and the purpose is adding structural information from MRI to functional information of PET images. The images decomposed with Nonsubsampled Contourlet Transform and then two images were fused with applying fusion rules. The coefficients of the low frequency band are combined by a maximal energy rule and coefficients of the high frequency bands are combined by a maximal variance rule. Finally, visual and quantitative criteria were used to... 

    A robust dual source level set method for three-dimensional echocardiography image segmentation

    , Article Journal of Theoretical and Applied Information Technology ; Volume 95, Issue 21 , 2017 , Pages 5701-5710 ; 19928645 (ISSN) Sahba, N ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
    2017
    Abstract
    Echocardiography as a common place device has been widely used for diagnosis. Segmentation of left ventricle just using the standard level set formulation based on the magnitude of intensity cannot restrict the contour evolution completely due to the lack of sharp edges. This paper aims to introduce a robust method for segmentation of three-dimensional echocardiography images based on two boundary maps namely distance map and probabilistic map as stopping criteria of contour evolution which are extracted using two different approaches. The distance map is extracted by applying Free Form Deformation (FFD) method on manually determined landmarks of initial spherical volume to register the... 

    An optimized probabilistic edge based level set method for left ventricle segmentation in echocardiography images

    , Article Biomedical Research (India) ; Volume 28, Issue 8 , 2017 , Pages 3788-3793 ; 0970938X (ISSN) Sahba, N ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
    Scientific Publishers of India  2017
    Abstract
    In this paper, an efficient approach for ultrasonic object segmentation with special application for left ventricle segmentation in echocardiography images is proposed. At first, an efficient hybrid trend for ultrasonic image edge detection is suggested. Then, a modified level set approach is introduced based on the extracted edges and the computed probabilistic map as the stopping criteria for the contour evolution. Both synthetic and clinical images are utilized as validation measures with respect to the prior techniques which indicate outperform results quantitatively and qualitatively. Left ventricle segmentation using proposed method illustrates expert-approved performance, providing a... 

    A review on state-of-the-art applications of data-driven methods in desalination systems

    , Article Desalination ; Volume 532 , 2022 ; 00119164 (ISSN) Behnam, P ; Faegh, M ; Khiadani, M ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    The substitution of conventional mathematical models with fast and accurate modeling tools can result in the further development of desalination technologies and tackling the need for freshwater. Due to the great capability of data-driven methods in analyzing complex systems, several attempts have been made to study various desalination systems using data-driven approaches. In this state-of-the-art review, the application of various artificial intelligence and design of experiment data-driven methods for analyzing different desalination technologies have been thoroughly investigated. According to the applications of data-driven methods in the field of desalination, the reviewed... 

    Perfect dominating sets in the cartesian products of prime cycles

    , Article Electronic Journal of Combinatorics ; Volume 14, Issue 1 N , 2007 , Pages 1-7 ; 10778926 (ISSN) Hatami, H ; Hatami, P ; Sharif University of Technology
    Australian National University  2007
    Abstract
    We study the structure of a minimum dominating set of C2n+1 n, the Cartesian product of n copies of the cycle of size 2n + 1, where 2n + 1 is a prime  

    Experimental determination of natural convection heat transfer coefficient in a vertical flat-plate solar air heater

    , Article Solar Energy ; Volume 82, Issue 10 , 2008 , Pages 903-910 ; 0038092X (ISSN) Hatami, N ; Bahadorinejad, M ; Sharif University of Technology
    2008
    Abstract
    In this study, natural convection heat transfer in a vertical flat-plate solar air heater of 2.5 m height and 1 m width, with one- and two-glass covers was studied experimentally. Totally six cases of airflow (two for air heater with one glass cover and four for air heater with two-glass covers) were considered. These cases included states that air could flow within spaces between absorber plate and glass covers or air was enclosed in such spaces. Absorber plate temperature, back-plate temperature, glass cover temperatures, mass flow rates of air within channels and the solar radiation were measured. The following relations are suggested:. For channels in which air could flow:Nu = 0.7362...