A Machine Learning Approach for Memory Resource Management in GPUs

, M.Sc. Thesis Sharif University of Technology Mohammadi Lak, Masoud (Author) ; Sarbazi Azad, Hamid (Supervisor)

Abstract

Nowadays, GPUs are used in applications such as graph computations and deep learning that require large data processing. These applications necessitate transferring a considerable amount of data between memory and computational units, which increases the average memory access latency. On the other hand, the poor performance of the L1 cache causes many reservation fails, resulting in increased energy consumption and reduced performance. In this thesis, we propose Smart Cache, a new smart cache management in GPUs. This approach models the cache replacement problem as a sequence labeling problem. Then, a machine learning model that combines support vector machine with one-hot encoding and...

Detecting Telegram Channels with Fake Members

, M.Sc. Thesis Sharif University of Technology Mohammadi, Behnam (Author) ; Aslani, Shirin (Supervisor) ; Talebian, Masoud (Supervisor)

Abstract

Nowadays, social media and messenger applications have found widespread usage in peoples’ lives, making them spend numerous hours on these services. As a consequence, it’s imperative for businesses to maintain presence and carry out advertising campaigns in these social networks. Telegram, which started out as a messaging application, has now grown into a prevalent social media platform in many countries. As a result, Telegram channels demonstrate high potential in publishing advertisements, furthering the promotion of products, and even asserting influence on political, societal, and economic situations. The cost of advertising on channels depends on the number the channel’s subscribers...

Strain and Stress Measurement by Image Processing Technique

, M.Sc. Thesis Sharif University of Technology Lak, Mehdi (Author) ; Assempour, Ahmad (Supervisor)

Abstract

This study presents an image processing technique for automatic strain and stress measurement in sheet metals. In order to measure the strain automatically, the sheet blank is electrochemically etched to create circular and rectangular grids. After press forming of the sheet, circular grids are deformed into elliptical grids and rectangular grids are deformed into quadrilateral grids. Different photos are captured for using in image processing technique. These photos are taken in different positions. Finally strain can be measured by processing these photos and the stress is obtained by using Levy-Mises flow rule. In this study, three methods of image processing technique are simultaneously...

Investigating the Effect of Chemical Coating on Reducing Evaporation from Saline Waters (Case Study of Lake Urmia)

, M.Sc. Thesis Sharif University of Technology Mohammadi, Mohammad Reza (Author) ; Tajrishi, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)

Abstract

This study tries to introduce chemical coatings to reducing evaporation from Lake Urmia(LU). In LU, average annual evaporation is estimated at more than 1,000 mm, more than 80% of evaporation occurring in the warmer months of the year. Therefore, by reducing water evaporation, especially in the warmer months of the year, the most crucial factor in water outflow from LU can be reduced.At first, on the scale of class A evaporation pan in Tehran, three kinds of chemical coatings constituted stearic acid, jojoba oil, and fatty alcohols of style and stearyl to reduce evaporation from the LU is investigated. Then the best coating that includes combine of style and stearyl alcohols with stearic...

Photocatalytic activity of TiO2-capped ZnO nanoparticles [electronic resource]

, Article Journal of Materials Science: Materials in Electronics ; 2011 , Vol. 23, Issue 2, P.361-369 Lak, A. (Aidin) ; Simchi, A. (Abdolreza) ; Nemati, Ziarat Ali ; Sharif University of Technology

Abstract

Using a combined hydrothermal and sol–gel route, TiO2-capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ~10 nm. Formation of Zn2TiO4 phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO2 shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm2) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy. Analysis of...

Gel-Electrolyte Based Dye-Sensitized Solar Cell Employing Mesoporous Tio2 Beads

, M.Sc. Thesis Sharif University of Technology Mohsenzadegan, Nima (Author) ; Askarim, Masoud (Supervisor) ; Mohammadi, Mohammad Reza (Co-Supervisor)

Abstract

Nowadays, dye-sensitized solar cells (DSSCs) are highly regarded as a cheap alternative for conventional silicon-based solar cells. Improvements of their efficiency and performance sustainability are two major challenges of their commercialization. Engineering of the photoanode electrode by controlling its thickness, chemical composition, and morphology was proposed as effective method in increasing the light conversion efficiency of the cells. In the present study, mesoporous TiO2 beads with different arrangements including pristine mesoporous beads, mixtures of mesoporous beads with nanoparticles, and in the form of two-layer structure of nanoparticles (as an active layer) and mesoporous...

Photocatalytic activity of TiO 2-capped ZnO nanoparticles

, Article Journal of Materials Science: Materials in Electronics ; Volume 23, Issue 2 , 2012 , Pages 361-369 ; 09574522 (ISSN) Lak, A ; Simchi, A ; Nemati, Z. A ; Sharif University of Technology

2012

Abstract

Using a combined hydrothermal and sol-gel route, TiO 2 -capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ∼10 nm. Formation of Zn 2TiO 4 phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO 2 shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm 2) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy....

Replacement of Pt with Graphene Derivatives in Counter Electrode of Dye-Sensitized Solar Cells

, M.Sc. Thesis Sharif University of Technology Mohammadnejad Hajlari, Sama (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Askari, Masoud (Supervisor)

Abstract

Dye-Sensitized solar cells are the third generation of solar cells that have the potential to increase efficiency as much as solar cells of previous generations, along with lower prices. The cathode electrode of the pigmented solar cell as one of the essential components of the cell plays the role of accelerating the oxidation reaction reduction of the electrolyte. Platinum often is used as a catalyst layer. To reduce production costs and maintain cell viability, platinum should replace with other materials at a lower cost and higher electrochemical activity. Recently, carbon materials have been considered for the production of inexpensive solar cells with suitable performance. Among...

Numerical Simulation of Secondary Sedimentation Tanks to Increase the Efficiency

, M.Sc. Thesis Sharif University of Technology Lak, Behzad (Author) ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Supervisor)

Abstract

Sedimentation tanks are one of the important and costly stages of water treatment process in which remained particles from previous stages settle down due to gravity force. In this research, the hydrodynamics of secondary settling tanks without and in the presence of particles is numerically investigated using VOF method in order to simulate the interphase using RNG k-ε for turbulence modelling. The simulations are performed by means of open-source code OpenFoam, and the code is developed to model particles in the flow. The calculated velocity profiles using VOF method show a reasonable agreement with the experimental data. Comparing the concentration profiles with experiments shows the...

Numerical Analysis of Hybrid Thermal Management System for Lithium-Ion Batteries using Liquid Cooling Method and Phase Change Materials

, M.Sc. Thesis Sharif University of Technology Mohammadi, Mohammad Reza (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Arianpour, Masoud (Supervisor)

Abstract

Lithium-ion battery is a type of rechargeable batteries that operates based on the movement of lithium ions within the battery, generating an electric current in the circuit. During charging and discharging, these batteries generate heat; therefore, it is crucial to employ an efficient battery thermal management system to maintain the temperature within a safe range. In this research, we analyze the temperature control of a battery pack comprising 168 largescale lithium-ion cells, configured as a rectangular cube with a capacity of 53 Ah, under a high discharge rate (5C). The analysis utilizes a hybrid battery thermal management system based on phase change materials (PCMs) and liquid...

Fruits and Vegetables Supply Chain Management (Case Study: Kerman Province)

, M.Sc. Thesis Sharif University of Technology Rajaei Lak, Razieh (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)

Abstract

One of the challenges of today's economy, is improving economic structures and reduce its dependence on oil revenues. Agricultural industry as an important part of the economy, is not dependent on oil revenues and improving its structure can have a significant impact on increasing revenues. Kerman province with a high proportion of horticultural products in the country, plays a significant role in Agricultural industry .However, the problem of water shortages in the country, highlighted the efficient use of water in economic purpose and crop-planning. By the problems with the current structure, lack of management of planting crops, lack of proper supply chain, redesign of agricultural supply...

Rapid formation of hydroxyapatite nanostrips via microwave irradiation

, Article Journal of Alloys and Compounds ; Volume 469, Issue 1-2 , 2009 , Pages 391-394 ; 09258388 (ISSN) Arami, H ; Mohajerani, M ; Mazloumi, M ; Khalifehzadeh, R ; Lak, A ; Sadrnezhaad, S. K ; Sharif University of Technology

2009

Abstract

Hydroxyapatite (HAp) nanostrips were rapidly obtained during a mild microwave heating method. Applying microwave irradiation to Ca(NO3)2·4H2O/CTAB/Na2HPO4 precursor solution, the HAp precipitation process was occurred directly and without common crystallographic transformations including dissolution and slow recrystallization. The cationic surfactant CTAB was used as a soft template to modify nucleation and growth process. TEM investigations showed that the fabricated nanostrips had a width and length of about 10 and 55 nm, respectively. The X-ray diffraction pattern revealed that the fabricated well-crystallized and high purity hydroxyapatite nanostrips had a pattern similar to the bone...

3D bundles of self-assembled lanthanum hydroxide nanorods via a rapid microwave-assisted route

, Article Journal of Alloys and Compounds ; Volume 473, Issue 1-2 , 2009 , Pages 283-287 ; 09258388 (ISSN) Mazloumi, M ; Shahcheraghi, N ; Kajbafvala, A ; Zanganeh, S ; Lak, A ; Mohajerani, M. S ; Sadrnezhaad, K ; Sharif University of Technology

2009

Abstract

Three-dimensional (3D) bundles of self-assembled lanthanum hydroxide nanorods with average crystallite size of about 20 nm were fabricated via a facile and rapid microwave-assisted chemical route. The obtained material was characterized with X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. The obtained nanorods have average diameter of about 115 nm and average length of about 730 nm. Self-assembly of primary La(OH)3 nanoparticles and their subsequent anisotropic growth along 〈2 0 0〉 direction, was proposed to be the mechanism for the formation of 3D bundles of nanorods, using TEM images. The thermal behavior of the...

Self-assembly of dandelion-like hydroxyapatite nanostructures via hydrothermal method

, Article Journal of the American Ceramic Society ; Volume 91, Issue 10 , 2008 , Pages 3292-3297 ; 00027820 (ISSN) Lak, A ; Mazloumi, M ; Mohajerani, M ; Kajbafvala, A ; Zanganeh, S ; Arami, H ; Sadrnezhaad, S. K ; Sharif University of Technology

2008

Abstract

Self-assembled dandelion-like hydroxyapatite (HAp) nanostructures were successfully synthesized via a mild template-free hydrothermal process, using ethylenediaminetetraacetic acid (EDTA) as the surfactant. The obtained dandelion-like HAp nanostructures were between 5 and 8 μm in diameter and were composed of radially oriented nanorods with an average diameter of about 200 nm. The X-ray diffraction analysis and Fourier transform infrared spectroscopy were used to characterize the crystalline phase and purity of the synthesized nanostructures. The Brunauer-Emmett-Teller surface area of the dandelion-like nanostructures was measured to be about 39 m2/g. The results of thermal analysis revealed...

Boehmite nanopetals self assembled to form rosette-like nanostructures

, Article Materials Letters ; Volume 62, Issue 26 , 2008 , Pages 4184-4186 ; 0167577X (ISSN) Mazloumi, M ; Attarchi, M ; Lak, A ; Mohajerani, M. S ; Kajbafvala, A ; Zanganeh, S ; Sadrnezhaad, S. K ; Sharif University of Technology

2008

Abstract

Rosette-like boehmite nanostructures were prepared successfully via a simple hydrothermal process. The obtained material was characterized with X-ray powder diffractometry (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Using Scherrer formula, the average crystallite size of the obtained boehmite rosettes was measured to be about 8 nm. It was shown that boehmite nanopetals with average width of about 41 nm determined by TEM, were formed during the hydrothermal process and then self assembled due to weak hydrogen bonds to fabricate boehmite rosettes. The specific surface area of the obtained rosette-like nanostructures was calculated through BET...

Long Term Effective Factors on House Price of Metropolises of Iran

, M.Sc. Thesis Sharif University of Technology Moeeni, Safoura (Author) ; Nili, Masoud (Supervisor)

Abstract

The notable share of housing sector in GDP (approximately five percent) shows this sector’s relation with macroeconomic activities. On the other hand, House as an asset leads housing sector to be affected by monetary and fiscal variables. A dynamic panel data was used in this study to evaluate the relations between housing sector and some macroeconomic variables in metropolises of Iran. As results show, in long term growth of liquidity, GDP per capita and sharp ratio have positive effects, and land per capita has negative effect on housing price in metropolises of Iran. Price increases have not been equal in different cities. Inequality of land price between metropolises and between...

Estimating an Index of Iran’s Informal Economy in 1350-1386 With Concentration on the Impact of Government’s Intervention by EMIMIC Model (The Multiple Indicators-Multiple Causes Model and Error-Correction Model)

, M.Sc. Thesis Sharif University of Technology Khandan, Abbas (Author) ; Nili, Masoud (Supervisor)

Abstract

In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran...

Water Quality Modeling of Urban Streams

, M.Sc. Thesis Sharif University of Technology Soltani, Maryam (Author) ; Tajrishy, Masoud (Supervisor)

Abstract

With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to...

The Political Economy Aspects of the Redistributive Role of Government in a General Equilibrium Micro-founded Macro Model

, M.Sc. Thesis Sharif University of Technology Zakeri, Hassan (Author) ; Nili, Masoud (Supervisor)

Abstract

The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed....

Measurement of Gini Coefficients by Means of Household’s Special CPI in Iran(1984-2005)

, M.Sc. Thesis Sharif University of Technology Ghasemi, Mojtaba (Author) ; Nili, Masoud (Supervisor)

Abstract

Gini coefficient is the most prevalent index for the measurement of inequality and is usually extracted by means of nominal variables based on income or expenditures of households. In this study we have extracted more accurate Gini coefficients. By using the raw data of Households Budget Survey (HBS) and STATA software, a special CPI for each household of the sample is extracted. Subsequently nominal expenditures are deflated by these special CPIs, and at last, Gini coefficients are extracted from real expenditures. Our findings indicate that in recent years, extracted Gini coefficients are remarkably higher than prevailing ones.