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rastegar-lari--amir
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Network-adaptive multipath video delivery over wireless multimedia sensor networks based on packet and path priority scheduling
, Article Proceedings - 2010 International Conference on Broadband, Wireless Computing Communication and Applications, BWCCA 2010, 4 November 2010 through 6 November 2010 ; 2010 , Pages 351-356 ; 9780769542362 (ISBN) ; Akbari, B ; Sharif University of Technology
2010
Abstract
In this paper we investigate multi-path transmission of video over Wireless Multimedia Sensor Networks (WMSNs). Our objective is to provide a transmission mechanism to improve the video quality perceived at the receiver while considering energy, bandwidth and delay constraints of the network. Our approach is based on packet and path priority scheduling in multipath video transmission over WMSN. Video packets are classified according to their types and more important packets are transmitted through paths with better conditions. Path conditions are evaluated by a score mechanism using variant parameters such as free buffer size, energy, hop count and packet loss. Since path conditions are...
Improving Packet Scheduling in Multpath Video Delivery Over Wireless Multimedia Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Akbari, Behzad (Supervisor)
Abstract
Recent advances in WSN have led to next generation of it for multimedia transmission which is WMSN. WMSN has several applications like environmental monitoring, advance health care delivery and etc. However, providing QoS requirements of transmitting video data like delay, bandwidth and packet loss with minimum distortion at perceived video quality over WMSN with resource constraints is a challenging problem. Using multipath routing protocol for video communication can increase bandwidth and decrease delay over WMSN. Moreover, all video packets have not the same effect on video distortion. We propose a scheduling mechanism which classifies packets according to their types and contents and...
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) ; 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) ; 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) ; 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) ; 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 ; 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) ; 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) ; 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
The Impact of Climate Shock on Child Labor
, M.Sc. Thesis Sharif University of Technology ; Keshavarz Haddad, Gholamreza (Supervisor)
Abstract
Precipitation in the water year 1396-1397 is the lowest in the past decade. The present study is conducted during this water year and focuses on the effects of climate variables such as temperature and precipitation on child labor supply between Tir 1397 and Farvardin 1398. Children and household characteristics are also taken into account when evaluating child labor supply using OLS and Logit methods. Estimation results indicate that both child work hours and participation in the job market decline with an increase in precipitation. Furthermore, how much time children spend working or studying is heavily influenced by parents' income. The temperature variable does not have a significant...
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) ; 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...
Modelling of 2D Fluidized Beds using the DPM Method and Investigation of the Pressure Effect on Particle-Wall Collision Frequency
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
In this work, a comprehensive survey on the different methods of modeling fluidized beds was done. Finally, the discrete particle method with soft particle approach was selected as the method of modeling the solid phase. For the gas phase, computational fluid dynamics (CFD) as the method of modeling is used. In order to verify our simulation results for the solid phase, a simulation of a bed with many particles distributed all around the bed was done. At the first second of the simulation, the gas phase flow was truned off and the particles were falling down. The results obtained with this method were verified with the references. For verification of the gas phase, a 2D bed with the gas...
Successful learning of academic word list via MALL: Mobile assisted language learning
, Article International Education Studies ; Volume 5, Issue 6 , Volume 5, Issue 6 , 2012 , Pages 99-109 ; 19139020 (ISSN) ; Sarab, M. R. A ; Lari, Z ; Sharif University of Technology
2012
Abstract
Mobile phones as new addition to information and communication technologies have created new ways to help learners in the process of foreign language learning. Given the importance of academic vocabularies for university students, this study tried to investigate the effectiveness of SMS on Iranian university students' vocabulary learning and retention. To this end forty five university freshman students with upper intermediate proficiency level were chosen to take part in this study. During 16 weeks of experiment, the participants of the experimental group (N = 28) were taught 320 head words from the Academic Word List (Coxhead, 2000) via SMS. During the same period of time the participants...
About Space Time
, M.Sc. Thesis Sharif University of Technology ; 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 ; 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 ; 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 ; 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 ; 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 ; 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,...
Assessment of message missing failures in FlexRay-based networks
, Article 13th Pacific Rim International Symposium on Dependable Computing, PRDC 2007, Melbourne, VIC, 17 December 2007 through 19 December 2007 ; 2007 , Pages 191-194 ; 0769530540 (ISBN); 9780769530543 (ISBN) ; Dehbashi, M ; Miremadi, S. G ; Farazmand, N ; Sharif University of Technology
2007
Abstract
This paper assesses message missing failures in a FlexRay-based network. The assessment is based on about 35680 bit-flip fault injections inside different parts of the FlexRay communication controller; the parts are: controller host interface, protocol operation control, coding and decoding unit, media access control and clock synchronization process. To do this, a FlexRay communication controller is modeled by Verilog HDL at the behavioral level. This HDL model of the controller is exploited to setup a FlexRay-based network composed of four nodes. The results of fault injection show that about 35% of faults led to the message missing failures. The controller host interface and the clock...