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hakimi-asiabar--mohammad
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Proposing a Value-based Pricing Model in IaaS based on the Market Segmentation Theory
, M.Sc. Thesis Sharif University of Technology ; Houshmnad, Mahmoud (Supervisor)
Abstract
Cloud infrastructure pricing framework is one of the challenges for many cloud economists and researchers, albeit its proper definition is one of the main requirements for business triumph. Efforts to focus on this issue have been extensively focused on a uniform market. Moreover, the models are mainly based on the cost factor and resources of cloud infrastructure, aiming to maximize revenue and profit margins for cloud service providers. Models that also consider the demand side and define criteria regarding the customer needs, preferences, and experiences are called value-based models, which provide a great competitive advantage for the providers aside from its higher profit margin and...
Optimizing the Investment Portfolio Including Life Insurance
, M.Sc. Thesis Sharif University of Technology ; Moddares Yazdi, Mohammad (Supervisor)
Abstract
Life insurance is a contract whereby the insurer becomes insured under certain conditions and for an amount known as insurance premium. Consequently, the insurer will pay the insured inheritors some given benefit as in the contract. There are different types of life insurance in the market. Other sectors of our proposed portfolio include risky and risk free investments. Household consumption is also considered as another variable in this package. This problem can be raised in both inflationary and non-inflationary states. You can also include a variable called loan. In the literature, this problem has been addressed by considering a sub-category of life insurance (Term Life Insurance)...
Frequency Comb Generation Using Time-Varying Electromagnetic Structures
, M.Sc. Thesis Sharif University of Technology ; Mehrany, Khashayar (Supervisor) ; Memarian, Mohammad (Co-Supervisor)
Abstract
This thesis presents a resonant time-periodic structure based on the Fabry-Perot resonator for frequency comb generation. Time-periodic structures cannot generate a frequency comb by themselves because side-harmonic amplitudes are really weak. However, due to resonant structure, it is expected that the side-harmonics, which are generated because of the time-periodic part of the structure, are increased if they are close to the main modes of the structure. But the results show that, generally, the amplitude of side harmonics, which are close to the main mode, is increased and far side-harmonics don't have remarkable amplitudes. However, we will show that if the modulation frequency of the...
Distribution of Economic Growth in Provinces of Iran and Their Effect to Each Other
, M.Sc. Thesis Sharif University of Technology ; Barakchian, Mahdi (Supervisor) ; Madanizadeh, Ali (Supervisor)
Abstract
Because of Economies of scale,There is trade-off between focus and allocation of economic resources in a region with the aim of balanced growth in all geographic areas and study the impact of economic growth on the other areas will be important . In the first study using the approach of exploratory spatial data analysis (ESDA) We will check the effectiveness of spatial dependence in the distribution of real per capita income growth of provinces of Iran. In the second part We will Study for the first time the severity of the impact of real per capita income growth on other areas in a neoclassical growth model and in addition to the spatial dependence we consider the effect of common factor....
Hardware Implementation of ANFIS Based Equalizer
, M.Sc. Thesis Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor) ; Ghorshi, Mohammad Ali (Co-Advisor)
Abstract
Nowadays, prolific usage of free air as a medium for data transmission leads interests to optimize the conditions of devices which are involved in wireless communication systems. Inter-Symbol Interference (ISI) distortion is a natural characteristic of wireless channels that occurs due to propagating electromagnetic waves in different directions. Due to different paths between a transmitter and a receiver, the received signal consists of several copies of the transmitted signal with different delays. The most common way of eliminating or mitigating the effects of ISI is channel equalization. The present work leads to implementing a supervised equalization in wireless communication. The...
Predicting the Optimal Operation Pattern of Municipal Wastewater Treatment Plant Using Artificial Intelligence Approaches
, M.Sc. Thesis Sharif University of Technology ; Torkian, Ayoub (Supervisor)
Abstract
With the growth of the population and the significant expansion of industries in the last century, many environmental problems have plagued developed and developing countries. One of these environmental problems is water pollution. Observing the effects of water pollution over time, sanitary and industrial wastewater treatment was proposed as a reliable solution. With technology development, wastewater treatment requirements have become stricter. The increase in energy consumption and wastewater treatment costs due to population growth and industrialization on the one hand and strict regulations, on the other hand, have forced those involved in this field to employ a variety of technical and...
Two novel chaos-based algorithms for image and video watermarking
, Article Iranian Journal of Electrical and Electronic Engineering ; Volume 8, Issue 2 , 2012 , Pages 97-107 ; 17352827 (ISSN) ; Talebi, S ; Hakimi, A ; Sharif University of Technology
IJEEE
2012
Abstract
In this paper we introduce two innovative image and video watermarking algorithms. The paper's main emphasis is on the use of chaotic maps to boost the algorithms' security and resistance against attacks. By encrypting the watermark information in a one dimensional chaotic map, we make the extraction of watermark for potential attackers very hard. In another approach, we select embedding positions by a two dimensional chaotic map which enables us to satisfactorily distribute watermark information throughout the host signal. This prevents concentration of watermark data in a corner of the host signal which effectively saves it from being a target for attacks that include cropping of the...
Development of a Model for Prediction of Inhibitors of HIV1 Virus
, M.Sc. Thesis Sharif University of Technology ; Jalali Heravi, Mehdi (Supervisor)
Abstract
The main aim of this study is developing a robust QSAR model for describing and predicting the inhibitory activities of O-(2-phthalimidoethyl)-N-substituted thiocarbamates derivatives as novel HIV-1 non-nucleoside reverse transcriptase (HIV-1 NNRTIs) inhibitors. These drugs change the active site of the reverse transcriptase enzyme, and finally halter the HIV reproduction cycle. As the first step of this study, a multiple linear regression (MLR) model was built but it has no satisfied prediction ability. As a next step, the nonlinear correlation of the molecular descriptors and activities has been investigated by using artificial neural networks (ANN). In this section the effects of variable...
Design of Airport Control Tower Structures Located in Seismic Zones
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Airport Traffic Control Towers (ATCTs) are among the most critical structures in an airport that are expected to keep their level of serviceability after severe strong earthquakes. Therefore analysis and design of these structures need a detailed investigation on the seismic behavior of the structure based on the structural characteristics. In this study three different existing reinforced concrete ATCTs have been investigated. As important parameters of earthquake design of structures, response modification factor (R-factor) of these towers will be determined. R-factor reduces elastic force level to design force level and contains the effect of ductility, overstrength. In Iranian seismic...
Graphene oxide interlayered in binder-free sulfur vapor deposited cathode for lithium-sulfur battery
, Article Journal of Physics D: Applied Physics ; Volume 55, Issue 16 , 2022 ; 00223727 (ISSN) ; Sanaee, Z ; Ghasemi, S ; Mohajerzadeh, S ; Sharif University of Technology
IOP Publishing Ltd
2022
Abstract
The main drawback of lithium-sulfur (Li-S) batteries which leads to a short lifetime, is the shuttle effect during the battery operation. One of the solutions to mitigate the shuttle effect is the utilization of interlayers. Herein, graphene oxide (GO) paper as an interlayer has been implemented between the sulfur cathode fabricated by the vapor deposition process as a binder-free electrode and a separator in a Li-S battery in order to gain a sufficient capacity. The morphological characteristics and electrochemical performance of the fabricated electrode have been investigated. The fabricated battery demonstrates an initial discharge capacity of 1265.46 mAh g-1 at the current density of 100...
Implementation of binder-free SnO2 NWs@C electrode and LiTFSI-based electrolyte for high-performance lithium-ion battery
, Article Journal of Physics D: Applied Physics ; Volume 56, Issue 1 , 2022 ; 00223727 (ISSN) ; Habibi, A ; Sanaee, Z ; Ghasemi, S ; Mohajerzadeh, S ; Sharif University of Technology
Institute of Physics
2022
Abstract
This study has investigated the effect of carbon coating on the electrochemical performance of SnO2 Nanowires (NWs) as an electrode along with a bis (trifluoromethane) sulfonimide lithium (LiTFSI)-based electrolyte in a lithium-ion battery (LIB). The vapor-liquid-solid approach has been used to grow SnO2 NWs on the stainless steel mesh current collector. The obtained results have demonstrated that the utilization of the LiTFSI-based electrolyte improved the battery performance with the SnO2 NWs electrode over the LiPF6-based electrolyte. This may be due to the formation of a stable and thin solid electrolyte interphase layer. Since bare SnO2 NWs exhibit inferior cycling stability due to...
Preparation of sulfur micro-particles suitable for lithium sulfur batteries using sulfur vapor deposition
, Article Materials Research Express ; Volume 6, Issue 10 , 2019 ; 20531591 (ISSN) ; Borzabadi Farahani, A ; Sanaee, Z ; Ghasemi, S ; Mohajerzadeh, S ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
The current paper reports the deposition of sulfur micro-particles using sulfur vapor deposition (SVD). Sulfur particles in size of 5 to 45 μm were deposited on a stainless steel substrate to be used as the cathode with porous structure in lithium sulfur (Li-S) batteries. Mass loading of about 0.5 mg cm-2 was obtained from this pure sulfur cathode. The structure of this binder-free cathode was characterized by field emission scanning electron microscopy (FESEM), x-ray spectroscopy (EDS), and x-ray diffraction (XRD). The electrochemical performance of the battery with two different organic liquid ether- and carbonate-based electrolytes was investigated and the results demonstrated that the...
Effect of a synthesized pulsed electrodeposited Tin/pbo2-ruo2nanocomposite on zinc electrowinning
, Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 31 , 2021 , Pages 11737-11748 ; 08885885 (ISSN) ; Rashchi, F ; Ghalekhani, M ; Dolati, A ; Razi Astaraei, F ; Sharif University of Technology
American Chemical Society
2021
Abstract
Nowadays, there is a growing interest in synthesizing electrodes used in zinc electrowinning, increasing active surface area, decreasing specific energy consumption, and the oxygen evolution reaction (OER) overpotential. In this study, modified nanocomposite anodes were synthesized by applying pulsed and constant direct current electrodeposition to improve the catalytic activity of the electrodes toward the oxygen evolution reaction (OER) and reduce energy consumption in zinc electrowinning. By decreasing particle size, the active surface area of PbO2-RuO2 nano-mixed composite electrode was 2.88 and 14.22 times greater than PbO2-RuO2 microcomposite and pure PbO2 electrodes, respectively....
Construction of an Experimental Device for Foaming Agent and an Experimental Study of the Properties of Foaming Agent
, M.Sc. Thesis Sharif University of Technology ; Bazargan, Mohammad (Supervisor)
Abstract
The primary purpose of acidizing operations in the oil and gas industry is to enhance hydrocarbon production. Acidizing has been a common and conventional method for years, especially when production engineers face issues like declining reservoir pressure leading to reduced production rates. Initially, the treatment solution is referred to as matrix acidizing. In acidizing operations, different additives are combined with the acid to control its behavior in the reservoir. These additives may include iron control agents, corrosion inhibitors, friction reducers, and more. Incompatibility among these additives, the acid, and reservoir fluids can lead to severe damage to the reservoir....
Numerical Analysis of An Annular Gas Turbine Combustor
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
The goal of this research is the simulation of the annular combustion chamber of the turbine engine utilized by liquid fuel. The achievement to this goal will lead to create numerical tools for parametric study, analysis and combustion chamber designing.For this reason simple geometry has been considered. This simplicity of geometry causes to facilitate in parametric study and decrease in saving time for modeling and meshing. This combustion chamber is a simplified model of engine CF6. In recent study, the k – ε realizable model has been used for turbulence modeling. For non-adiabatic condition, chemical reaction is dissolved by utilizing probability density function along with laminar...
Comparison of periodontally compromised splinted teeth and implant supported fixed partial denture: a three-dimensional finite element analysis on bone response
, Article Journal of long-term effects of medical implants ; Volume 31, Issue 2 , 2021 , Pages 1-8 ; 19404379 (ISSN) ; Kadkhodazadeh, M ; Talebi Ardakani, M. R ; Movahhedy, M. R ; Mirakhori, M ; Hakimi, A ; Broukhim, M ; Sharif University of Technology
NLM (Medline)
2021
Abstract
Introduction - This study aimed to compare the amount and pattern of stress and strain distributed around periodontally compromised splinted teeth and the two-implant abutments supported six-unit fixed partial denture (FPD) using finite element analysis (FEA). Methods and Materials - Six mandibular anterior teeth of a dental model were scanned and the scans were transferred to 3D CAD design and finite element software. Jaw bone was also designed and the teeth were splinted by fiber-reinforced composite (FRC) band. In another model, two implants were placed at the site of canine teeth and a six-unit FPD was designed over them. Models were transferred to finite element software and after...
A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]
, Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology
Abstract
Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...
Theoretical and Experimental Study to Conversion of AUC to UO2 by Microwave Heating
, Ph.D. Dissertation Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Ghannadi Maragheh, Mohammad (Co-Advisor) ; Ghasemi, Mohammad Reza (Co-Advisor)SAR Imaging Using the TomoSAR Technique to Resolve Multiple Scatterers
, M.Sc. Thesis Sharif University of Technology ; Bastani, Mohammad Hassan (Supervisor) ; Karbasi, Mohammad (Co-Supervisor)
Abstract
During the last few years, the study of urban environment structures is considered as a research field of interest in remote sensing. In satellite observations of the earth's surface, continuous imaging in terms of time and space has caused the remote sensing technique to be proposed as a useful and efficient tool for the analysis of urban areas. Obtaining quantitative spatial information from the urban environment in fields such as determining the height of buildings plays an essential role in urban planning, monitoring damage to buildings, establishing communication bases and digital cities. During the last two decades, the use of Tomosar approach in order to reconstruct the structures of...
Estimating Possible Effects of Subsidies in Competition and Development of Fixed Broadband Internet
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor) ; Rahmati, Mohammad Hossein (Supervisor)
Abstract
In this work, the dynamic competition between firms providing internet services is studied. The framework is Markov equilibrium whereby structural parameters are obtained using two-step estimations, allowing for analyzing the situation in case of subsidies for service upgrade. The results show that such subsidy has little effect on the number of firms while increasing the number of fast firms