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    Leveraging dark silicon to optimize networks-on-chip topology

    , Article Journal of Supercomputing ; Volume 71, Issue 9 , 2015 , Pages 3549-3566 ; 09208542 (ISSN) Modarressi, M ; Sarbazi-Azad, H ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    This paper presents a reconfigurable network-on-chip (NoC) for many-core chip multiprocessors (CMPs) in the dark silicon era, where a considerable part of high-end chips cannot be powered up due to the power and bandwidth walls. Core specialization, which trades off the cheaper silicon area with energy-efficiency, is a promising solution to the dark silicon challenge. This approach integrates a selection of many diverse application-specific cores into a single many-core chip. Each application then activates those cores that best match its processing requirements. Since active cores may not always form a contiguous active region in the chip, such a partially active many-core CMP requires some... 

    Design and simulation of a high power single mode 1550nm InGaAsP VCSELs

    , Article IEICE Electronics Express ; Volume 8, Issue 13 , 2011 , Pages 1096-1101 ; 13492543 (ISSN) Faez, R ; Marjani, A ; Marjani, S ; Sharif University of Technology
    In the present work, a new structure of vertical cavity surface emitting laser (VCSEL) is designed and simulated. In this structure, InGaAsP is used as the active region which is sandwiched between GaAs/AlGaAs distributed bragg mirror at the top of structure and GaAs/AlAs distributed bragg mirror at the bottom. In this work, the hole etching depth was continued down to the top of lower spacer layer while in the previous work the hole etching depth was only down to top of the upper spacer. In this way, the threshold current decrement of 76.52% and increment the power by 28% from 5mW to 6.4mW at bias current of 9mA was achieved. In this paper, device characteristics such as light power versus... 

    Fibre position effects on the operation of opto-pair fibre displacement sensors

    , Article Optics and Laser Technology ; Volume 43, Issue 4 , 2011 , Pages 814-819 ; 00303992 (ISSN) Jafari, R ; Golnabi, H ; Sharif University of Technology
    In this article, two optical-fibre probes used in displacement measurements are reported. In one arrangement, two optical fibres with protective buffer jackets are placed together, while in the second arrangement, the protective buffer jackets are removed and the two fibres are placed with the claddings in contact, with a concomitant smaller centrecentre distance. As the core and cladding diameters are the same in both probes, the effect of the centrecentre distance on double-fibre designs can be investigated. The reflected output powers are recorded for the probes as a function of the axial distance from a reflective surface. A theoretical model is also implemented, which considers the... 

    The effects of recombination lifetime on efficiency and JV characteristics of InxGa1-xN/GaN quantum dot intermediate band solar cell

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 42, Issue 9 , July , 2010 , Pages 2353-2357 ; 13869477 (ISSN) Es'Haghi Gorji, N ; Movla, H ; Sohrabi, F ; Hosseinpour, A ; Rezaei, M ; Babaei, H ; Sharif University of Technology
    We introduce a new third generation of solar cell structure which inserts different-sized quantum dots in the active region of a pin structure. Generating an intermediate band in the bandgap of the host material makes a good overlap with a part of solar spectrum. The effect of the recombination mechanisms on efficiency and currentvoltage characteristics of this intermediate band solar cell is calculated. We deduce that the increase in recombination lifetime of the excited carriers can improve the characteristics of this structure. This result can be a route which helps us to take the effect on solar cell characteristics into consideration  

    A new mathematical approach for detection of active area in human brain fMRI using nonlinear model

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 22, Issue 5 , 2010 , Pages 409-418 ; 10162372 (ISSN) Taalimi, A ; Fatemizadeh, E ; Sharif University of Technology
    Functional magnetic resonance imaging (fMRI) is widely-used for detection of the brain's neural activity. The signals and images acquired through this imaging technique demonstrate the human brain's response to pre-scheduled tasks. Several studies on blood oxygenation level-dependent (BOLD) signal responses demonstrate nonlinear behavior in response to a stimulus. In this paper we propose a new mathematical approach for modeling BOLD signal activity, which is able to model nonlinear and time variant behaviors of this physiological system. We employ the Nonlinear Auto Regressive Moving Average (NARMA) model to describe the mathematical relationship between output signals and predesigned...