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    Deformation of outer representations of galois group II

    , Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 6, Issue 2 , 2011 , Pages 33-41 ; 17354463 (ISSN) Rastegar, A ; Sharif University of Technology
    2011
    Abstract
    This paper is devoted to deformation theory of "anabelian" representations of the absolute Galois group landing in outer automorphism group of the algebraic fundamental group of a hyperbolic smooth curve defined over a number-field. In the first part of this paper, we obtained several universal deformations for Lie-algebra versions of the above representation using the Schlessinger criteria for functors on Artin local rings. In the second part, we use a version of Schlessinger criteria for functors on the Artinian category of nilpotent Lie algebras which is formulated by Pridham, and explore arithmetic applications  

    Deformation of outer representations of Galois group

    , Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 6, Issue 1 , 2011 , Pages 35-52 ; 17354463 (ISSN) Rastegar, A ; Sharif University of Technology
    2011
    Abstract
    To a hyperbolic smooth curve defined over a number-field one naturally associates "ananabelian" representation of the absolute Galois group of the base field landing in outer automorphism group of the algebraic fundamental group. In this paper, we introduce several deformation problems for Lie-algebra versions of the above representation and show that, this way we get a richer structure than those coming from deformations of "abelian" Galois representations induced by the Tate module of associated Jacobian variety. We develop an arithmetic deformation theory of graded Lie algebras with finite dimensional graded components to serve our purpose  

    Arithmetic Teichmuller theory

    , Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 14, Issue 2 , 2019 , Pages 157-171 ; 17354463 (ISSN) Rastegar, A ; Sharif University of Technology
    Iranian Academic Center for Education, Culture and Research  2019
    Abstract
    By Grothendieck’s anabelian conjectures, Galois representations landing in outer automorphism group of the algebraic fundamental group which are associated to hyperbolic smooth curves defined over number-fields encode all the arithmetic information of these curves. The Goal of this paper is to develop an arithmetic Teichmuller theory, by which we mean, introducing arithmetic objects summarizing the arithmetic information coming from all curves of the same topological type defined over number-fields. We also introduce Hecke-Teichmuller Lie algebra which plays the role of Hecke algebra in the anabelian framework. © 2019 Academic Center for Education, Culture and Research TMU  

    Arithmetic teichmuller theory

    , Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 14, Issue 2 , 2019 , Pages 157-171 ; 17354463 (ISSN) Rastegar, A ; Sharif University of Technology
    Iranian Academic Center for Education, Culture and Research  2019
    Abstract
    By Grothendieck’s anabelian conjectures, Galois representations landing in outer automorphism group of the algebraic fundamental group which are associated to hyperbolic smooth curves defined over number-fields encode all the arithmetic information of these curves. The Goal of this paper is to develop an arithmetic Teichmuller theory, by which we mean, introducing arithmetic objects summarizing the arithmetic information coming from all curves of the same topological type defined over number-fields. We also introduce Hecke-Teichmuller Lie algebra which plays the role of Hecke algebra in the anabelian framework. © 2019 Academic Center for Education, Culture and Research TMU  

    Ihara-Type results for siegel modular forms

    , Article Bulletin of the Iranian Mathematical Society ; Volume 46, Issue 3 , 2020 , Pages 693-716 Rastegar, A ; Sharif University of Technology
    Springer  2020
    Abstract
    Let p be a prime not dividing the integer n. By an Ihara result, we mean existence of a cokernel torsion-free injection from a full lattice in the space of p-old modular forms into a full lattice in the space of all modular forms of level pn. In this paper, we will prove an Ihara result in the number field case, for Siegel modular forms. The case of elliptic modular forms is discussed in Ihara (Discrete subgroups of Lie groups and applications to moduli, Oxford University Press, Bombay, 1975). We will use a geometric formulation for the notion of p-old Siegel modular forms (Rastegar in BIMS 43(7):1–23, 2017). Then, we apply an argument by Pappas, and prove the Ihara result using density of... 

    On a theorem of Ihara

    , Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 1-9 ; 10263098 (ISSN) Rastegar, A ; Sharif University of Technology
    Sharif University of Technology  2005
    Abstract
    Let p be a prime number and let n be a positive integer prime to p. By an Ihara-result, one means the existence of an injection with torsion-free cokernel, from a full lattice, in the space of p-old modular forms, into a full lattice, in the space of all modular forms of level np. In this paper, Ihara-results are proven for genus two Siegel modular forms, Siegel-Jacobi forms and Hilbert modular forms. Ihara did the genus one case of elliptic modular forms [1]. A geometric formulation is proposed for the notion of p-old Siegel modular forms of genus two, using clarifying comments by R. Schmidt [2] and, then, following suggestions in an earlier paper [3] on how to prove Ihara results. The main... 

    Arithmetic deformation theory of lie algebras

    , Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 18, Issue 1 , 2023 , Pages 19-32 ; 17354463 (ISSN) Rastegar, A ; Sharif University of Technology
    Iranian Academic Center for Education, Culture and Research  2023
    Abstract
    This paper is devoted to deformation theory of graded Lie algebras over Z or Zl with finite dimensional graded pieces. Such deformation problems naturally appear in number theory. In the first part of the paper, we use Schlessinger criteria for functors on Artinian local rings in order to obtain universal deformation rings for deformations of graded Lie algebras and their graded representations. In the second part, we use a version of Schlessinger criteria for functors on the Artinian category of nilpotent Lie algebras which is formulated by Pridham, and explore arithmetic deformations using this technique. © 2023 Academic Center for Education, Culture and Research TMU  

    Investigating the impacts of plug-in hybrid electric vehicles on power distribution systems

    , Article IEEE Transactions on Smart Grid ; Volume 4, Issue 3 , 2013 , Pages 1351-1360 ; 19493053 (ISSN) Shafiee, S ; Fotuhi Firuzabad, M ; Rastegar, M
    2013
    Abstract
    Despite the economic and environmental advantages of plug-in hybrid electric vehicles (PHEVs), the increased utilization of PHEVs brings up new concerns for power distribution system decision makers. Impacts of PHEVs on distribution networks, although have been proven to be noticeable, have not been thoroughly investigated for future years. In this paper, a comprehensive model is proposed to study the PHEV impacts on residential distribution systems. In so doing, PHEV fundamental characteristics, i.e., PHEV battery capacity, PHEV state of charge (SOC), and PHEV energy consumption in daily trips, are accurately modeled. As some of these effective characteristics depend on vehicle owner's... 

    About Space Time

    , M.Sc. Thesis Sharif University of Technology Naderi, Mojtaba (Author) ; Rastegar, Arash (Supervisor)
    Abstract
    Einstein's general theory of relativity is an admirable successful and unifier geometrical modeling among concepts of space, time and gravity. This theory along with special theory of relativity made a massive change in our physical view and this, especially in its historical context, has deep and interesting consequences in man's philosophical viewpoint which can be studied. Some parts of this thesis relates to these consequences. Some of these interesting consequences may be hidden by computional or mathematical viewpoint and often these equations do not contain enough intuition. in one part, we provide a formulizatin of Einstein's equaion that is intuitional which can be translated in... 

    Synthesis and Characterization of Electrospun Ceramic Nanofibers

    , M.Sc. Thesis Sharif University of Technology Rastegar, Soroush (Author) ; Bagheri, Habib (Supervisor)
    Abstract
    Electrospinning is a simple and versatile technique for producing polymeric and ceramic nanofibers. The conventional procedure for fabrication of ceramic nanofibers is a combination of sol-gel techniques and electrospinning. The main challenge is the spin polymer nanofiber in fabricate of fibers with diameter from 1 to 100 nm, while their standard deviation are as low as possible. Uniform beads free polyamidenanofibers with lower diameter were fabricated.A 18% w/w of polyamide in formic acid was chosen and the effect of magnetic field, adding magnetic ionic liquid surfactant, auxiliary electrode on the main fiber were investigated. They termsfiber 1 to fiber 5. The mean diameters of 489,... 

    Tropical Algebraic Geometry

    , M.Sc. Thesis Sharif University of Technology Yaghmayi, Keyvan (Author) ; Rastegar, Arash (Supervisor)
    Abstract
    Tropical algebraic geometry is a fairly new branch in geometry which is called so in honor of Brazilian mathematician Imre Simon who was pioneer of this field.The set equipped with the addition and multiplication is a semifield.Algebraic geometry objects like algebraic varieties can be defined over.Polynomials and rational functions are defined over.The functions that they define are piecewise linear and concave functions and the set of points where they are nonlinear is a tropical variety which is a concave polyhedral. Thus, tropical algebraic geometry is a piecewise linear version of algebraic geometry.Another approach to tropical algebraic geometry comes back to the works of Russian... 

    Deep Learning for Multimodal Data

    , M.Sc. Thesis Sharif University of Technology Rastegar, Sarah (Author) ; Soleymani, Mahdieh (Supervisor)
    Abstract
    Recent advances in data recording has lead to different modalities like text, image, audio and video. Images are annotated and audio accompanies video. Because of distinct modality statistical properties, shallow methods have been unsuccessful in finding a shared representation which maintains the most information about different modalities. Recently, deep networks have been used for extracting high-level representations for multimodal data. In previous methods, for each modality, one modality-specific network was learned. Thus, high-level representations for different modalities were extracted. Since these high-level representations have less difference than raw modalities, a shared... 

    A New Approach Based on Mathematical Modelling and Fuzzy Multi Criteria Decision Making for Supplier Selection in Green Supply Chain

    , M.Sc. Thesis Sharif University of Technology Rastegar, Mohsen (Author) ; Hajji, Alireza (Supervisor)
    Abstract
    Recently, reducing greenhouse gas emissions and the damage to the environment is very important. Due to the increasing environmental awareness of the people on the one hand, and government pressure to reduce damage to the environment on the other hand, has led organizations to pay more attention to this important issue. In addition, these organizations in order to participate in the global competition, should consider green criteria along with other criteria. Hence, the organizations to outsourcing part of their work are looking for Suppliers who along with other criteria also meet the criteria for being green. In this study, a new two-stage approach based on fuzzy... 

    , M.Sc. Thesis Sharif University of Technology (Author) ; Rastegar, Arash (Supervisor)
    Abstract
    Our goal is to reformulate MKR-dictionary for geodesic foliations on hyperbolic 3-manifolds. Where the closed geodesic is considered as a knot. In this new perspective, by topological interpretation at arithmetical objects and considering the etale fundamental group, the ground has been prepared to obtain an analogy between the theory of knots and the algebraic numbers theory. The analogy between knots and prime numbers was pointed out by B. Mazur and also by Y. Manin and developed by the work of Kapranov and Reznikov. Using this analogy, Mazur formulated the Chebotarev density theorem related to prime numbers in number fields for an infinite sequence of knot on a three-dimensional manifold,... 

    Discovery of Effective Genes Via Differential Gene Expression Networks

    , M.Sc. Thesis Sharif University of Technology Rastegar, Soheil (Author) ; Motahari, Abolfazl (Supervisor)
    Abstract
    With the emergence of high-throughput gene expression data collection methods, the development of more precise analytical techniques to extract patterns from these data is increasingly necessary. These methods, of course, vary depending on the specific pattern being targeted for extraction. However, identifying key genes and biological pathways responsible for major changes remains the primary challenge in understanding the structure of gene regulatory networks. Understanding these regulatory networks serves as a foundation for a wide range of biological intervention strategies, which can have diverse objectives. In the field of gene expression network inference, numerous challenges exist,... 

    Optimal Control of Spacecraft on the Earth-Moon Lagrange Point Orbits considering Sun and other Planets and Elliptic Orbit Perturbations

    , M.Sc. Thesis Sharif University of Technology Ghorbani, Mehrdad (Author) ; Assadian, Nima (Supervisor)
    Abstract
    In this thesis, optimal station keeping of spacecraft on the closed-orbits near the Earth-Moon Lagrange points has been investigated. Lagrange points L1 and L2 are unstable equilibrium points of the circular restricted three-body problem (CRTBP), and periodic orbits near them are the destination of modern missions. However, perturbations resulting from the gravitational forces of the Sun and the planets and the eccentricity of the orbit of the Moon around the Earth make the Lagrange point unstable, even L4 and L5, which are stable in CRTBP. The most suitable choice for spacecraft mission near the collinear Lagrange points is the Halo and other closed-orbits around them, which need... 

    Orbit Design and Optimization of Satellite Constellation for Regional Coverage

    , M.Sc. Thesis Sharif University of Technology Borhani, Amir (Author) ; Assadian, Nima (Supervisor)
    Abstract
    In this thesis, the satellite constellation orbit design for regional coverage is investigated. The orbits of satellites in a constellation for Earth observation missions play a crucial role in performance and characteristics of the mission; for example the image resolution, the area of coverage, and the coverage interval. In this thesis the problem is to find the optimal initial orbital elements for meeting the earth observation mission objectives for one or several sites. The cost functions are the total coverage time, the maximum gap time, time average gap, altitude, and number of satellites. The problem is solved in a multi-objective manner for different combination of two of the above... 

    Autonomous Orbit Estimation for Regional Navigation Satellites

    , M.Sc. Thesis Sharif University of Technology Memaran, Mohsen (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis, autonomous orbit estimation of regional navigation satellites has been investigated. Estimation of satellite orbit is an integral part of satellite navigation, which may be executed via assistance of ground station. As the satellite is exposed to the ground station view, range, direction and rate of range is measured by mean of ranging instrumentation relative to ground reference, hence the precise position is calculated. In this thesis a set of satellites are investigated in a unique structure called constellation with the purpose of navigation. The occurrence which is likely to happen in this condition, is the failure of ground station under certain circumstances or losing... 

    Fabrication and Characterization of a UF Ceramic Membrane based on TiO_2 Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Mirkazemi, Amin (Author) ; Taghavinia, Nima (Supervisor)
    Abstract
    UF membranes are widely used in various industries now, a major type of these membranes are ceramic membranes which are resistant to high temperatures and corrosive fluids. In this thesis we developed an anisotropic UF ceramic membrane based on 20nm TiO2 nanoparticles on a prous sustrate. We had two major challenges, the first one was to find a suitable prous substrate and the second one was to find an appropriate coating method. Our main task was to optimise the process conditions to achive a crackless and uniform membrane layer with minimal ups and downs. Lots of coating methods and TiO2 inks have been tried, finally we used a coating method which we called it “Soft Blade Coating”, with... 

    Continuous-thrust Trajectory Optimization in the Binary Asteroids System

    , M.Sc. Thesis Sharif University of Technology Ashrafi, Mehnraz (Author) ; Asadian, Nima (Supervisor)
    Abstract
    In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the...