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yousefzadeh-asl-miandoab--ehsan
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Unifying L1 Data Cache and Shared Memory in GPUs
, M.Sc. Thesis Sharif University of Technology ; Sarbazi Azad, Hamid (Supervisor)
Abstract
Graphics Processing Units (GPUs) employ a scratch-pad memory (a.k.a., shared memory) in each streaming multiprocessor to accelerate data sharing among the threads in a thread block and provide a software-managed cache for the programmers.However, we observe that about 60% of GPU workloads of several well-known benchmark suites do not use shared memory. Morever, among those workloads that use shared memory, about 42% of shared memory is not utilized, on average. On the other hand, we observe that many general purpose GPU applications suffer from the low hit rate and limited bandwidth of L1 data cache.We aim to use shared memory space and its corrsponding bandwidth for improving L1 data cache,...
NURA: A framework for supporting non-uniform resource accesses in gpus
, Article Proceedings of the ACM on Measurement and Analysis of Computing Systems ; Volume 6, Issue 1 , 2022 ; 24761249 (ISSN) ; Mahani, N ; Baxishi, H ; Yousefzadeh Asl Miandoab, E ; Sadrosadati, M ; Sarbazi Azad, H ; Sharif University of Technology
Association for Computing Machinery
2022
Abstract
Multi-application execution in Graphics Processing Units (GPUs), a promising way to utilize GPU resources, is still challenging. Some pieces of prior work (e.g., spatial multitasking) have limited opportunity to improve resource utilization, while other works, e.g., simultaneous multi-kernel, provide fine-grained resource sharing at the price of unfair execution. This paper proposes a new multi-application paradigm for GPUs, called NURA, that provides high potential to improve resource utilization and ensures fairness and Quality-of-Service (QoS). The key idea is that each streaming multiprocessor (SM) executes Cooperative Thread Arrays (CTAs) belong to only one application (similar to the...
An audio band low voltage CT-ΔΣ modulator with VCO-based quantizer
, Article 18th IEEE International Conference on Electronics, Circuits, and Systems, ICECS 2011, 11 December 2011 through 14 December 2011 ; December , 2011 , Pages 232-235 ; 9781457718458 (ISBN) ; Sharifkhani, M ; Sharif University of Technology
2011
Abstract
This paper presents the design and implementation of a low power, low voltage, continuous time delta sigma modulator for audio band in 90 nm CMOS technology. A VCO-based integrator and quantizer are used. Inherent dynamic element matching (DEM) of the quantizer eliminates the need for explicit DEM logic which results in a short excess-delay and power saving. Simulation results show that the modulator achieves 78 dB SNDR and 87 dB SNR in a 20 kHz input bandwidth and dissipates 106 μW from 1 V supply. The power consumption for different parts is discussed
An Investigation on Physical and Photochemical Properties of Sol-Gel Derived MWCNT-WO3 Nanocomposite thin Films
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
WO3 have good electrochromic, gas sensor, photocatalyst, phoelectrochemical (PEC) properties. due its properties, tungsten oxide have many application in technology and industry. In this thesis, pure WO3 thin film and MWCNT-WO3 nanocomposite thin films with different weight percent of MWCNT/WO3 utilize for energy domain, particular hydrogen production with phoelectrochemical reactions spiliting water. For this purpose, initially WO3 thin films were deposited on glass and ITO substrates using sol-gel dip-coating method. Optical and surface properties of the films dried at 100ºC and annealed at 400 ºC had been investigated. UV-Visible spectrophotometer, atomic force microscopy (AFM), X-ray...
Synthesis and Investigation on Physical and Photoelectrochemical Properties of Visible Active TiO2/Graphene Based Nanocomposite Thin Films for Hydrogen Production
, Ph.D. Dissertation Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
World population growth, depletion of fossil fuels resources depletion and increased air pollution resulting from their consumption, human society has had to replace fossil fuels with renewable sources. In this context, the production of hydrogen using solar energy is feasible candidate to replace fossil fuels, which can be produced by water splitting in a photoelectrochemical (PEC) cell using an appropriate photocatalyst. This clean production method has been attended by many researchers in recent years. The most common photocatalyst for the conversion of sunlight to hydrogen by splitting water is Titanium dioxide (TiO2). But high energy gap and fast electron-hole recombination rate in TiO2...
A 10MHz CTDSM with differential VCO-based quantizer in 90nm
, Article Proceedings of the 2013 8th International Conference on Design and Technology of Integrated Systems in Nanoscale Era, DTIS 2013 ; 2013 , Pages 128-133 ; 9781467360388 (ISBN) ; Hajian, A ; Sharifkhani, M ; Sharif University of Technology
2013
Abstract
This paper presents a new architecture for VCO-based Continuous Time Delta Sigma Modulators. This approach is based on the differential configuration for the quantizer while maintains its inherent dynamic element matching property. Consuming no additional power and area compared to the conventional scheme, this architecture can eliminate the even orders of harmonic distortion and achieve higher linearity. Theoretical analysis for signal to quantization noise, power and area consumption and mismatch effect is provided. To illustrate the effectiveness of the new architecture in continuous time modulators, a modulator with 640 MHz sampling rate utilizing the mentioned quantizer is simulated in...
Application of particle swarm optimization and genetic algorithm for optimization of a southern Iranian oilfield
, Article Journal of Petroleum Exploration and Production ; Volume 11, Issue 4 , 2021 , Pages 1781-1796 ; 21900558 (ISSN) ; Dehghan, A ; Yousefzadeh, R ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Optimization of the placement and operational conditions of oil wells plays an important role in the development of the oilfields. Several automatic optimization algorithms have been used by different authors in recent years. However, different optimizers give different results depending on the nature of the problem. In the current study, a comparison between the genetic algorithm and particle swarm optimization algorithms was made to optimize the operational conditions of the injection and production wells and also to optimize the location of the injection wells in a southern Iranian oilfield. The current study was carried out with the principal purpose of evaluating and comparing the...
Design and Implementation of Low Power Delta Sigma Modulator for Audio Application
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
iN This thesis, Design and implementation of a low voltage, low power Delta-Sigma Modulator (DSM) is presented. System level considerations have been discussed thoroughly. In addition a systematic design flow in the context of continuous time delta sigma modulators is provided. While voltage-domain signal processing becomes more difficult in deep sub-micron processes, a finer time resolution is achievable. Time-domain quantizers can ameliorate the design challenges of flash quantizers which arises from lower supply voltages and higher fraction of comparator metastable region. VCO based quantizer such as voltage to frequency and voltage to phase considered as time domain quantizers can be a...
Constructing BiVO4/Graphene/TiO2 nanocomposite photoanode for photoelectrochemical conversion applications
, Article Journal of Electroanalytical Chemistry ; Volume 763 , 2016 , Pages 1-9 ; 15726657 (ISSN) ; Faraji, M ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier B.V
2016
Abstract
BiVO4/Graphene/TiO2 as a novel nanocomposite photoanode was designed, synthesized and characterized for photoelectrochemical application. BiVO4/Graphene nanocomposite was initially synthesized by photocatalytic process and then, BiVO4/Graphene/TiO2 nanocomposite thin film was prepared by deposition of the BiVO4/Graphene solution onto the surface of sol-gel derived TiO2 thin film. Morphology, crystal structure, surface chemical composition and optical properties of the synthesized BiVO4/Graphene/TiO2 nanocomposite thin film were characterized and compared with the BiVO4/Graphene and pure TiO2 samples. Observations of scanning electron microscopy (SEM) images revealed that the surface of the...
Band-gap narrowing and electrochemical properties in N-doped and reduced anodic TiO2 nanotube arrays
, Article Electrochimica Acta ; Volume 270 , 2018 , Pages 245-255 ; 00134686 (ISSN) ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was...
Improved efficiency in front-side illuminated dye sensitized solar cells based on free-standing one-dimensional TiO2 nanotube array electrodes
, Article Solar Energy ; Volume 184 , 2019 , Pages 115-126 ; 0038092X (ISSN) ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Although morphological disorder of nanotube structure is further down than the nanoparticular electrode, its density of traps are the hindering effects in the charge transport. In this study, crack-free TiO2 nanotube membranes, which obtained through a re-anodizing process, are fixed on transparent fluorine–tin-oxide glass by applying a few drops of Titanium Isopropoxide without needing the TiO2 powder paste. Front-side illuminated dye sensitized solar cells fabricated by undoped, N-doped and blue TiO2 nanotube membranes are investigated. The electrical characteristics of TiO2 nanotube based dye sensitized solar cells are followed by theoretical analysis using simple one-diode model....
Effect of surface energy on nano-resonator dynamic behavior
, Article International Journal of Mechanical Sciences ; Volume 119 , 2016 , Pages 51-58 ; 00207403 (ISSN) ; Nejat Pishkenari, H ; Meghdari, A ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Presented herein is a comprehensive analysis on the size-dependent dynamic behaviors of electrostatically actuated nano-resonator including surface stresses effect. To this end, partial differential equation of nano-resonator based on Gurtin–Murdoch and Euler–Bernoulli theories is converted to ordinary differential equation utilizing assumed mode method. Effect of applied DC voltage on stability and bi-stability of nano-resonator is investigated and it revealed that surface elasticity and stress affect the bi-stability region of nano-resonator. By plotting frequency response of the resonator, hardening and softening behavior of nano-resonator are analyzed and it is shown that surface effect...
The Impact of Unconditional Cash Subsidies on the time Allocation of Household by using “Dose-Response Function”
, M.Sc. Thesis Sharif University of Technology ; Keshavarz Haddad, Gholamreza (Supervisor)
Abstract
This study aims to estimate impact of the energy subsidy reform on households’ head time allocation in rural and urban areas in to 2011 to 2013 by making use of treatment effect particularly dose response function approach. Our main contribution is estimation and calculation of labor supply reaction to the unconditional cash transfer by dose of the subsidy that they received, while the previous works in this literature have used the well know binary variable of being in the exposure of program. To control for the demand determinants which are deriving the labor demand, we include the province level GDP and unemployment rate in the model. Our findings show that the subsidy dose does not have...
Dynamic analysis of electrostatically actuated nanobeam based on strain gradient theory
, Article International Journal of Structural Stability and Dynamics ; Volume 15, Issue 4 , 2014 ; ISSN: 02194554 ; Pishkenari, H. N ; Yousefi Koma, A ; Sharif University of Technology
2014
Abstract
In this study, dynamic response of a micro- and nanobeams under electrostatic actuation is investigated using strain gradient theory. To solve the governing sixth-order partial differential equation, mode shapes and natural frequencies of beam using Euler–Bernoulli and strain gradient theories are derived and then compared with classical theory. Galerkin projection is utilized to convert the partial differential equation to ordinary differential equations representing the system mode shapes. Accuracy of proposed one degree of freedom model is verified by comparing the dynamic response of the electrostatically actuated micro-beam with analogue equation and differential quadrature methods....
Nonlocal and strain gradient based model for electrostatically actuated silicon nano-beams
, Article Microsystem Technologies ; Vol. 21, Issue 2 , 2014 , pp. 457-464 ; Online ISSN: 1432-1858 ; Yousefi-Koma, A ; Pishkenari, H. N ; Sharif University of Technology
2014
Abstract
Conventional continuum theory does not account for contributions from length scale effects which are important in modeling of nano-beams. Failure to include size-dependent contributions can lead to underestimates of deflection, stresses, and pull-in voltage of electrostatic actuated micro and nano-beams. This research aims to use nonlocal and strain gradient elasticity theories to study the static behavior of electrically actuated micro- and nano-beams. To solve the boundary value nonlinear differential equations, analogue equation and Gauss–Seidel iteration methods are used. Both clamped-free and clamped–clamped micro- and nano-beams under electrostatical actuation are considered where...
Poly silicon nanobeam model based on strain gradient theory
, Article Mechanics Research Communications ; Vol. 62 , December , 2014 , pp. 83-88 ; ISSN: 00936413 ; Yousefi-Koma, A ; Pishkenari, H. N ; Sharif University of Technology
2014
Abstract
Conventional continuum theory does not account for contributions from length scale effects. Failure to include size-dependent contributions can lead to underestimates of deflection and stresses of micro and nanobeams. This research aims to use strain gradient elasticity theory to model size-dependent behavior of small beams. In this regard, Young's modulus and length scale parameters of poly silicon are estimated by fitting the predicted static pull-in voltages to the reported experimental results in the literature. The results demonstrate that decreasing the beam thickness results in higher pull-in voltage, lower deflection and lower sensitivity to axial stress and mid-plane stretching in...
Nonlinear dynamics of nano-resonators: an analytical approach
, Article Microsystem Technologies ; Volume 22, Issue 9 , 2016 , Pages 2259-2271 ; 09467076 (ISSN) ; Nejat Pishkenari, H ; Yousefi Koma, A ; Sharif University of Technology
Springer Verlag
2016
Abstract
Prior to the design and fabrication of MEMS/NEMS devices, analysis of static and dynamic behaviors of these systems is necessary. In the present study, the nonlinear dynamic behavior of micro- and nano-mechanical resonators is investigated and classified based on the resonator’s physical parameters for first time. The Galerkin method is used to convert the distributed-parameter model to a nonlinear ordinary differential equation where mid-plane stretching, axial stress, DC electrostatic and AC harmonic voltages are taken into account. To obtain the analytical frequency response of the micro resonator near its primary resonance, the second order multiple scales method is applied to the...
Nonlinear dynamics of nano-resonators: an analytical approach
, Article Microsystem Technologies ; 2015 ; 09467076 (ISSN) ; Nejat Pishkenari,, H ; Yousefi Koma, A ; Sharif University of Technology
2015
Abstract
Prior to the design and fabrication of MEMS/NEMS devices, analysis of static and dynamic behaviors of these systems is necessary. In the present study, the nonlinear dynamic behavior of micro- and nano-mechanical resonators is investigated and classified based on the resonator’s physical parameters for first time. The Galerkin method is used to convert the distributed-parameter model to a nonlinear ordinary differential equation where mid-plane stretching, axial stress, DC electrostatic and AC harmonic voltages are taken into account. To obtain the analytical frequency response of the micro resonator near its primary resonance, the second order multiple scales method is applied to the...
MWCNT/WO3 nanocomposite photoanode for visible light induced water splitting
, Article Journal of Solid State Chemistry ; Volume 204 , 2013 , Pages 341-347 ; 00224596 (ISSN) ; Reyhani, A ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
2013
Abstract
The Multi-walled carbon nanotube (MWCNT)/WO3 nanocomposite thin films with different MWCNT's weight percentages were prepared by sol-gel method as visible light induced photoanode in water splitting reaction. Weight percentage of MWCNT in the all nanocomposite thin films was confirmed by TGA/DSC analysis. According to XPS analysis, oxygenated groups at the surface of the MWCNT and stoichiometric formation of WO3 thin films were determined, while the crystalline structure of the nanocomposite samples was studied by XRD indicating (0 0 2) peak of MWCNT in the monoclinic phase of WO3. The influence of different weight percentage (wt%) of MWCNT on WO3 photoactivity showed that the electron...
Analysis and Development of Security Enhancements in Layer 2 Ethernet Based Networks
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor)
Abstract
Ethernet is among the most popular forms of data networking in the world. It has been widely used for local area networks and recently, it has also become very popular in metro area networks. As the usage of Ethernet grows, security and privacy of data transport using Ethernet becomes more important. As a result, there have been a lot of developments in improving security of Ethernet. In this thesis, we first provide a brief introduction of data security concepts. Then we briefly review important encryption standards. We focus on IEEE MACsec standard to provide the required security for Ethernet data transport. We have implemented the core encryption/decryption algorithms using HDL codes. We...