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    Machine Learning in 2D Compressed Sensing Datasets

    , M.Sc. Thesis Sharif University of Technology Keshvari, Fatemeh (Author) ; Babaiezadeh, Massoud (Supervisor)
    Abstract
    Compressed Sensing (CS) technique refers to the digitalization process that efficiently reduces the number of measurements below the Nyquist rate while preserving signal structure. This technique was originally developed for the analysis of vector datasets. An x ∈R^n vector is transformed into an y ∈R^m vector so that n≪m. For a sufficient number of measurements, this transformation has been shown to preserve the signal structure. Therefore, the technique has been applied to machine learning applications.2D-CS was further developed for matrices (image datasets) so that they could be directly applied to matrices without flattening. X ∈R^(n×n) is transformed into Y ∈R^(m×m) via 2D-CD such... 

    Sampling and Distortion Tradeoffs for Band-limited Periodic Signals

    , Ph.D. Dissertation Sharif University of Technology Mohammadi, Elaheh (Author) ; Marvasti, Farokh (Supervisor)
    Abstract
    One of the funadmental problems in signal processing is finding the best sampling strategy of a continuous time signal, and then finding the best strategy for compressing the obtained signal samples. The sampling and compression steps are designed with the aim of minimizing the distortion of the reconstructed signal. The problem of finding the best sampling strategy has been widely studied in the signal processing literature. In particular, the Nyquist–Shannon sampling theorem gives a sufficient condition for perfect reconstruction of a continuous-time signal of finite bandwidth. Most of the signal processing literature deals with deterministic signals, with relatively less attention paid to... 

    A seamless-pitched graphene nanoribbon field effect transistor

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 74 , November , 2015 , Pages 414-420 ; 13869477 (ISSN) Haji Nasiri, S ; Moravvej Farshi, M. K ; Faez, R ; Sharif University of Technology
    Elsevier  2015
    Abstract
    This paper proposes a graphene nanoribbon field effect transistor (GNRFET) consisting of pitched semiconducting GNRs as the channels that are connected to the metallic graphene source/drain in a seamless fashion. We obtained the diagrams for frequency bandwidths, step time responses, and Nyquist stability for the seamless pitched GNRFET (SP-GNRFET) with a channel having 100 pitched GNRs at 10 nm pitch in the common source configuration with various dimensions of the GNRs. The aforementioned diagrams were also obtained for the pitched carbon nanotube field effect transistor (CNTFET) with a channel having 100 pitched CNTs at 10 nm pitch in the common source configuration with various... 

    Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode

    , Article International Journal of Hydrogen Energy ; Volume 34, Issue 2 , 2009 , Pages 859-869 ; 03603199 (ISSN) Danaee, I ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2009
    Abstract
    The electro-oxidation of methanol on nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the...