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    Finite-SNR diversity-multiplexing tradeoff in multi-relay channels

    , Article 2013 Iran Workshop on Communication and Information Theory ; 2013 ; 9781467350235 (ISBN) Haddadpour, F ; Gholami, E ; Rastegar, S. H ; Behroozi, H ; Sharif University of Technology
    2013
    Abstract
    In this paper, we investigate the diversity-multiplexing tradeoff (DMT) for multi-relay channels in finite-SNR regime. In our analysis, we consider the decode and forward (DF) relaying strategy and a line of sight path from source to destination. First, we determine the outage probability in a multi-relay scenario and obtain its exact analytical expressions. Then, the outage probability of a multi-relay channel with relay selection is calculated and provided as a closed-form expression. Based on these results, we determine the DMT in finite-SNR regime. Finally, using simulation results, we show that our analysis has accurate results which coincides with that of obtained from Monte-Carlo... 

    Magnetic and electric field assisted electrospun polyamide nanofibers for on-line μ-solid phase extraction and HPLC

    , Article RSC Advances ; Vol. 4, Issue. 94 , 2014 , pp. 52590-52597 ; ISSN: 20462069 Bagheri, H ; Piri-Moghadam, H ; Rastegar, S ; Sharif University of Technology
    2014
    Abstract
    The effects of applied magnetic and electric fields on electrospinning were investigated to produce more efficient nanofibers. Considering the previous extensive studies, polyamide nanofibers were prepared by a conventional approach and under auxiliary electric and magnetic fields. The first sorbent was synthesized by electrospinning of a solution of 18% polyamide in formic acid. The second and third types of polyamide were prepared similarly while the electrospinning processes were assisted by an electric and a magnetic field. The third type of polyamide contained a magnetic ionic liquid (MIL) to induce sufficient magnetic susceptibility in the polymeric solution. The SEM images revealed... 

    Centralized home energy management in multi-carrier energy frameworks

    , Article 2015 IEEE 15th International Conference on Environment and Electrical Engineering, EEEIC 2015 - Conference Proceedings, 10 June 2015 through 13 June 2015 ; 2015 , Pages 1562-1566 ; 9781479979936 (ISBN) Rastegar, M ; Fotuhi-Firuzabad, M ; Zareipour, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    This paper proposes a centralized optimization-based home energy management (HEM) scheme in a macro energy hub structure. An energy hub management system manages the aggregated load of a group of residential micro energy hubs to minimize the total load deviation. The operational characteristics of the household appliances and the threshold energy cost of the customers are incorporated in the propounded method to provide the customers' comfort. Numerical studies show the effectiveness of the proposed method performance  

    Rate adaptation and power allocation for time-correlated MISO Rayleigh fading channel with delay-limited HARQ

    , Article IEEE International Conference on Communications, 10 June 2012 through 15 June 2012 ; 2012 , Pages 3915-3919 ; 15503607 (ISSN) ; 9781457720512 (E-ISBN) Rastegar, S. H ; Vakilinia, S ; Khalaj, B. H ; Sharif University of Technology
    2012
    Abstract
    In this paper, we consider the problem of optimum rate adaptation and power allocation to maximize the delay-limited throughput (DLT) in a time-correlated 2×1 MISO Rayleigh fading channel with Hybrid ARQ in Chase-Combining mode (HARQ-CC). To this aim, we have first formulated the DLT equation based on the outage probability for 2×1 MISO-HARQ channel. We show that exact analytical calculation of the outage probability is not tractable. Therefore, we approximate the outage probability using a log-normal approximation approach. Based on such approximation, optimal rate and power allocations are derived. Finally, using Monte-Carlo simulation, we show that the approximation method provides... 

    Home energy management incorporating operational priority of appliances

    , Article International Journal of Electrical Power and Energy Systems ; Volume 74 , 2016 , Pages 286-292 ; 01420615 (ISSN) Rastegar, M ; Fotuhi Firuzabad, M ; Zareipour, H. R ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    Home energy management (HEM) schemes persuade residential customers to actively participate in price-based demand response (DR) programs. In these price-based HEM methods, a controller schedules the energy consumption of household's controllable appliances in response to electricity price signals, considering various customer preferences. Although numerous methods have been recently proposed for HEM application, prioritizing the operation of controllable appliances from the customer's viewpoint in price-based HEM has not been addressed, which is the focus of the present paper. To do this, the value of lost load (VOLL) of each appliance is defined to indicate the operational priority of that... 

    Electrospun titania sol-gel-based ceramic composite nanofibers for online micro- solid-phase extraction with high-performance liquid chromatography

    , Article Journal of Separation Science ; Vol. 37, issue. 15 , August , 2014 , pp. 1982-1988 ; ISSN: 16159306 Bagher, H ; Piri-Moghadam, H ; Rastegar, S ; Taheri, N ; Sharif University of Technology
    2014
    Abstract
    Titanium(IV) tetraisopropoxide was employed as a metal oxide sol-gel precursor to prepare ceramic composite nanofibers by the electrospinning system. To facilitate this process and obtain the desired nanofibers with higher aspect ratios and surface area, poly(vinylpyrrolidone) was added to the sol of titania. Four ceramic nanofibers sheets based on titania were prepared while each sheet contained different transition metals such as Fe-Mn, Fe-Ni, Fe-Co, and Fe-Mn-Co-Ni. The scanning electron microscope images showed good homogeneity for all the prepared ceramic composites with a diameter range of 100-250 nm. The sorption efficiency was investigated by a micro-solid-phase extraction setup in... 

    Distilled water production with combination of solar still and thermosyphon heat pipe heat exchanger coupled with indirect water bath heater – Experimental study and thermoeconomic analysis

    , Article Applied Thermal Engineering ; Volume 176 , 2020 Rastegar, S ; Kargarsharifabad, H ; Rahbar, N ; Shafii, M. B ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The aim of this study is to provide a solution for supplying distilled water used in indirect water bath heaters in the pressure reduction stations. A particular type of distilled water production system consists of a typical solar still and a heat pipe heat exchanger was constructed for recovering heat from the exhaust of an indirect gas heater. The system was tested under the climatic conditions of Semnan-Iran. Experimental results showed that in active type, the average daily production rate of distilled water would be 2.06 times higher than passive type. Also, in the proposed system, the average daily energy efficiency and the exergy efficiency would be 65.5% and 41% higher than the... 

    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... 

    A probabilistic energy management scheme for renewable-based residential energy hubs

    , Article IEEE Transactions on Smart Grid ; Volume 8, Issue 5 , 2017 , Pages 2217-2227 ; 19493053 (ISSN) Rastegar, M ; Fotuhi Firuzabad, M ; Zareipour, H ; Moeini Aghtaieh, M ; Sharif University of Technology
    2017
    Abstract
    This paper proposes a new framework for home energy management (HEM) in the context of renewable-based residential energy hub using a probabilistic optimization approach. Different energy converters and storages, including combined heat and power, a plug-in hybrid electric vehicle, a heat storage unit, solar panels, and generic household appliances, are considered in the energy hub. The customer's energy cost is considered as the objective of the HEM optimization problem and different operational limits of the energy hub components are modeled as the constraints. The two-point estimate method is incorporated in this paper to model the uncertainty associated with output power of the rooftop... 

    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... 

    MDL-CW: A multimodal deep learning framework with cross weights

    , Article 2016 IEEE Conference on Computer Vision and Pattern Recognition, 26 June 2016 through 1 July 2016 ; Volume 2016-January , 2016 , Pages 2601-2609 ; 10636919 (ISSN) ; 9781467388511 (ISBN) Rastegar, S ; Soleymani Baghshah, M ; Rabiee, H. R ; Shojaee, S. M ; Sharif University of Technology
    IEEE Computer Society  2016
    Abstract
    Deep learning has received much attention as of the most powerful approaches for multimodal representation learning in recent years. An ideal model for multimodal data can reason about missing modalities using the available ones, and usually provides more information when multiple modalities are being considered. All the previous deep models contain separate modality-specific networks and find a shared representation on top of those networks. Therefore, they only consider high level interactions between modalities to find a joint representation for them. In this paper, we propose a multimodal deep learning framework (MDLCW) that exploits the cross weights between representation of... 

    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... 

    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... 

    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,... 

    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...