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hassan--ahmadvand
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Full Analysis Antenna Ferrite Disk in Range of Negative Permeability
, M.Sc. Thesis Sharif University of Technology ; Rejaei, Behzad (Supervisor)
Abstract
In wireless communication systems increasing the gain of antennas is seminal to increase in coverage and data transmission rate, and reducing the possible errors. One of the main factors for improving the antenna gain is matching the polarizations of the transmitter and the receiver antennas. Towards this end, both the transmitter and the receiver antennas should have the same axial ratio, specific direction and polarizations. As far as the flexibility of the direction angle between the transmitter and the receiver is concerned, the so-called circular polarization is preferred do the linear polarization. The antennas with circular polarizations are prominently utilized in satellites,...
Using Data Variety in Progressive Processing of Big Data in Cloud Environment
, Ph.D. Dissertation Sharif University of Technology ; Goudarzi, Maziar (Supervisor)
Abstract
Nowdays a large number of companies are faced with Big Data processing. Due to the lack of budget or time, it may not be possible to process all the input data. Data variety is one of the main features of Big Data. Considering Data variety can help us to solve the problem of resource capacity. In this research, we focused on the impact of data variety on the performance of Big Data processing. In the first part, we offer a solution for increasing the performance of progressive Big Data processing. We provide a simple low-overhead mechanism to quickly assess the significance of each data portion, and show its effectiveness in finding the best ranking of data portions. We continue by...
Design and Fabrication of 2D Multi-Electrode Array (MEA)Devices to Evaluate Functionality of Neural Cell Network and Cardiac Cells
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Microelectrode array technology is a broad platform for studying and characterization of the electrophysiological properties of excitable tissues derived from both brain and heart in vitro. Microelectrode arrays can either record or stimulate cells by accessing multiple sites of neural networks and cell tissues and detect signals from all sources around each electrode simultaneously. By using recorded signals, one can detect cell potential changes and its minor fluctuations. Unlike intracellular recording techniques, the noninvasive interface of microelectrode arrays with cells provides durable studying of neural networks and cell tissues. Using related microelectronics fabrication...
SAIR: significance-aware approach to improve QoR of big data processing in case of budget constraint
, Article Journal of Supercomputing ; Volume 75, Issue 9 , 2019 , Pages 5760-5781 ; 09208542 (ISSN) ; Goudarzi, M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
Nowadays, a wide range of enterprises are faced with big data processing in different domains such as transaction operations, business calculations and analytical computations. Large-scale computing is an approach for big data processing. Due to the cost of large-scale computing and limitations of enterprise budgets, it is hardly possible to process all the input data and therefore the Quality of Result (QoR) may be affected. SAIR is an approach to improve QoR of big data processing for aggregative usages based on significance variety when there is a budget constraint. In this paper, the most significant data portions have been assigned to the most efficient resources in terms of time and...
Robust Estimation and Control of a Planet Lander
, M.Sc. Thesis Sharif University of Technology ; Kiani, Maryam (Supervisor)
Abstract
This study has focused on the important problem of landing on a planet as an important current and future space mission. In this regard, dynamics modeling and integrated state estimation and control problems have been investigated in different views. To this aim, first a novel concurrent representation for translational and rotational kinematics has been developed based on the extension of modified Rodrigues parameters to dual space. This parameter set, called dual modified Rodrigues parameters (DMRP), is then utilized to establish an integrated roto-translational dynamic. The proposed DMRP-based kinematics and dynamics have been verified via comparison to traditional methods of...
Error Correction with Partial Knowledge about the Noise
, M.Sc. Thesis Sharif University of Technology ; Memarzadeh, Laleh (Supervisor)
Abstract
Currently, quantum noise stands as one of the foremost challenges in the realization of quantum algorithms and the development of quantum technologies. Consequently, finding methods to eliminate or reduce the impact of noise is imperative. This thesis explores the possibility of correcting the expectation values of observables on a quantum system, specifically a qubit quantum system experiences quantum noise, given partial knowledge of the noise. We begin by reviewing essential background information, including some of the most common methods for correcting noise, with a particular focus on the noise deconvolution technique. Subsequently, we introduce our method for correcting the...
Analysis and Evaluation of Real Timeliness and Safety of VANET
,
M.Sc. Thesis
Sharif University of Technology
;
Jahangir, Amir Hossein
(Supervisor)
Abstract
The increasing number of road accidents and fatalities have yielded the introduction of several solutions by related industries such as automobile manufacture. Proposed solutions can be classified into two categories: passive, such as airbags, and active such as ABS ad ITS-based technologies. Inter vehicles communication let the communication between vehicles(V2V) or between vehicles and road infrastructure (V2I) by relying on DSRC technology and standards. Intelligent Transportation System (ITS) has three main types of applications namely safety, traffic and commercial. Safety applications are the main goal of vehicular communication, and real time guarantee in safety applications is so...
Solvatochromic Parameters Effects Study on Kinetics of Aromatic Nucleophilic Substitution Reaction in Mixture of Ionic Liquid and Alcoholic Solvents
,
M.Sc. Thesis
Sharif University of Technology
;
Gholami, Mohammad Reza
(Supervisor)
Abstract
Solute-solvent and solvent-solvent interactions were investigated in mixtures of ethylammonium propionate with methanol, ethanol, isopropanol and propanol. Solvatochromic parameters, including normalized polarity ( ), polarity/dipolarizability (p*), hydrogen-bond donor (a), and hydrogen-bond acceptor (ß) abilities, were determined in these mixtures. Parameters showed synergetic effects in mixtures of ionic liquid and alcohols due to the preferential solvation. General polarity shows an ideal behavior in all mixtures, polarity/dipolarizability exhibit increasing profile in all mixtures preferential salvation caused nonideal behavior for hydrogen-bond acceptor parameter Solvent...
Chemometric-based determination of polycyclic aromatic hydrocarbons in aqueous samples using ultrasound-assisted emulsification microextraction combined to gas chromatography-mass spectrometry
, Article Journal of Chromatography A ; Volume 1413 , September , 2015 , Pages 117-126 ; 00219673 (ISSN) ; Sereshti, H ; Parastar, H ; Sharif University of Technology
Elsevier
2015
Abstract
In the present research, ultrasonic-assisted emulsification-microextraction (USAEME) coupled with gas chromatography-mass spectrometry (GC-MS) has been proposed for analysis of thirteen environmental protection agency (EPA) polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Tetrachloroethylene was selected as extraction solvent. The main parameters of USAEME affecting the efficiency of the method were modeled and optimized using a central composite design (CCD). Under the optimum conditions (9 μL for extraction solvent, 1.15% (w/v) NaCl (salt concentration) and 10min for ultrasonication time), preconcentration factor (PF) of the PAHs was in the range of 500-950. In order to have a...
Second-order calibration for the determination of fatty acids in pomegranate seeds by vortex-assisted extraction-dispersive liquid-liquid micro-extraction and gas chromatography-mass spectrometry
, Article RSC Advances ; Volume 5, Issue 15 , 2015 , Pages 11633-11643 ; 20462069 (ISSN) ; Sereshti, H ; Parastar, H ; Sharif University of Technology
2015
Abstract
Multivariate curve resolution-alternating least squares (MCR-ALS) as a second-order calibration algorithm was proposed for the simultaneous analysis of eighteen fatty acid methyl esters (FAMEs) in a standard mixture and pomegranate seed sample using vortex-assisted extraction-dispersive liquid-liquid microextraction (VAE-DLLME), followed by gas chromatography-mass spectrometry (GC-MS). The chemometric resolution, identification and quantification of the target FAMEs in the standard mixture and real sample (i.e., the pomegranate seed) were carried out successfully in the presence of some uncalibrated interferences. The lack of fit (LOF) and reverse match factor (RMF) were used for the...
Gapprox: using gallup approach for approximation in big data processing
, Article Journal of Big Data ; Volume 6, Issue 1 , 2019 ; 21961115 (ISSN) ; Goudarzi, M ; Foroutan, F ; Sharif University of Technology
SpringerOpen
2019
Abstract
As Big Data processing often takes a long time and needs a lot of resources, sampling and approximate computing techniques may be used to generate a desired Quality of Result. On the other hand, due to not considering data variety, available sample-based approximation approaches suffer from poor accuracy. Data variety is one of the key features of Big Data which causes various parts of data to have different impact on the final result. To address this problem, we develop a data variety aware approximation approach called Gapprox. Our idea is to use a kind of cluster sampling to improve the accuracy of estimation. Our approach can decrease the amount of data to be processed to achieve the...
DV-DVFS: merging data variety and DVFS technique to manage the energy consumption of big data processing
, Article Journal of Big Data ; Volume 8, Issue 1 , 2021 ; 21961115 (ISSN) ; Foroutan, F ; Fathy, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Data variety is one of the most important features of Big Data. Data variety is the result of aggregating data from multiple sources and uneven distribution of data. This feature of Big Data causes high variation in the consumption of processing resources such as CPU consumption. This issue has been overlooked in previous works. To overcome the mentioned problem, in the present work, we used Dynamic Voltage and Frequency Scaling (DVFS) to reduce the energy consumption of computation. To this goal, we consider two types of deadlines as our constraint. Before applying the DVFS technique to computer nodes, we estimate the processing time and the frequency needed to meet the deadline. In the...
DV-DVFS: merging data variety and DVFS technique to manage the energy consumption of big data processing
, Article Journal of Big Data ; Volume 8, Issue 1 , 2021 ; 21961115 (ISSN) ; Foroutan, F ; Fathy, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Data variety is one of the most important features of Big Data. Data variety is the result of aggregating data from multiple sources and uneven distribution of data. This feature of Big Data causes high variation in the consumption of processing resources such as CPU consumption. This issue has been overlooked in previous works. To overcome the mentioned problem, in the present work, we used Dynamic Voltage and Frequency Scaling (DVFS) to reduce the energy consumption of computation. To this goal, we consider two types of deadlines as our constraint. Before applying the DVFS technique to computer nodes, we estimate the processing time and the frequency needed to meet the deadline. In the...
A novel Markov random field model based on region adjacency graph for T1 magnetic resonance imaging brain segmentation
, Article International Journal of Imaging Systems and Technology ; Volume 27, Issue 1 , 2017 , Pages 78-88 ; 08999457 (ISSN) ; Yousefi, S ; Manzuri Shalmani, M. T ; Sharif University of Technology
John Wiley and Sons Inc
2017
Abstract
Tissue segmentation in magnetic resonance brain scans is the most critical task in different aspects of brain analysis. Because manual segmentation of brain magnetic resonance imaging (MRI) images is a time-consuming and labor-intensive procedure, automatic image segmentation is widely used for this purpose. As Markov Random Field (MRF) model provides a powerful tool for segmentation of images with a high level of artifacts, it has been considered as a superior method. But because of the high computational cost of MRF, it is not appropriate for online processing. This article has proposed a novel method based on a proper combination of MRF model and watershed algorithm in order to alleviate...
Removal of an organic pollutant from waste water by photocatalytic behavior of AgX/TiO2 loaded on mordenite nanocrystals
, Article Research on Chemical Intermediates ; Volume 38, Issue 8 , 2012 , Pages 1975-1985 ; 09226168 (ISSN) ; Salari, H ; Ahmadvand, S ; Gholami, M. R ; Sharif University of Technology
Springer
2012
Abstract
Mordenite (MOR) nanocrystals were synthesized using the hydrothermal method. Sol-gel and deposition methods were utilized to modify the zeolite surface with TiO2 and then AgBr or AgCl particles. Photocatalysts were characterized by using X-ray diffraction, Brunauer-Emmett-Teller (BET), and scanning electron microscopy techniques. Activity was evaluated by photodegradation of Acid Blue 92 as an azo dye. The effect of silver halide deposition on the photocatalytic behavior of the prepared nanocomposites was studied under both ultraviolet (UV) and visible light, and the results were compared. The results showed that AgCl/TiO2/MOR was more active under UV, while with visible source,...
Analytical calculation for input impedance of a circularly-polarized ferrite disk antenna including higher order modes
, Article International Journal of RF and Microwave Computer-Aided Engineering ; Volume 29, Issue 8 , 2019 ; 10964290 (ISSN) ; Heydari, M. B ; Rejaei, B ; Ghalibafan, J ; Sharif University of Technology
John Wiley and Sons Inc
2019
Abstract
We propose an accurate analytical model for a circularly polarized antenna comprising a normally magnetized, grounded ferrite disk with a metalized top surface. The antenna is assumed to be excited by a conventional current probe. In the case of a thin ferrite disk, the electromagnetic fields of the dominant mode of the antenna do not vary in the direction normal to the disk. However, with increasing thickness of the ferrite disk, higher order modes start to affect antenna characteristics such as resonance frequency. This work presents an analysis of the structure that takes into account all higher modes of the antenna. To validate the theoretical calculations, HFSS simulations are...
Thermomechanical synthesis of hybrid in-situ Al-(Al3Ti+Al2O3) composites through nanoscale Al-Al2TiO5 reactive system
, Article Journal of Alloys and Compounds ; Volume 789 , 2019 , Pages 493-505 ; 09258388 (ISSN) ; Azarniya, A ; Madaah Hosseini, H. R ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this work, nanostructured aluminum titanate (Al2TiO5 or AT) was synthesized by the citrate sol gel method. Then, different volume fractions of this ceramic were blended with Al powder through different durations of the high-energy vibratory milling. The effect of mechanical milling on the thermal degradation of AT in exposure to Al and formation mechanism of in-situ Al2O3 and Al3Ti particles were explored in three conditions: (i) in the powder form; (ii) after annealing of green compact; and (iii) after hot extrusion. In the powder form, it was shown that the mechanical milling is able to significantly diminish the thermal stability of AT, so that the required temperature for the Al3Ti...
Structural Design of a Launch Vehicle with Reusable First Stage
, M.Sc. Thesis Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
Aerodynamics loads and aeroheating during reentry, are one of the challenging issues in designing One of the main challenges in the design and application of reusable spacecrafts is the aerodynamic and thermal loads acting on their structures during reentry into the atmosphere. For this reason, all the concepts/prototypes presented in the 20th century were either not fully reusable, or were partially canceled, or did not have economic justification. In this report, the aerodynamic loads on the first stage of a launch vehicle during the launch and return phases have been investigated. Due to the fact that the main part of the first stage of the vehicle includes fuel and oxidizer tanks, the...
Anti-HER2 VHH targeted magnetoliposome for intelligent magnetic resonance imaging of breast cancer cells
, Article Cellular and Molecular Bioengineering ; Volume 10, Issue 3 , 2017 , Pages 263-272 ; 18655025 (ISSN) ; Rahbarizadeh, F ; Ahmadvand, D ; Madaah Hosseini, H. R ; Sharif University of Technology
2017
Abstract
The combination of liposomes with magnetic nanoparticles, because of their strong effect on T2 relaxation can open new ways in the innovative cancer therapy and diagnosis. In order to design an intelligent contrast agent in MRI, we chose anti-HER2 nanobody the smallest fully functional antigen-binding fragments evolved from the variable domain, the VHH, of a camel heavy chain-only antibody. These targeted magnetoliposomes bind to the HER2 antigen which is highly expressed on breast and ovarian cancer cells so reducing the side effects as well as increasing image contrast and effectiveness. Cellular iron uptake analysis and in vitro MRI of HER2 positive cells incubated with targeted...
Fabrication & Characterization of Al-Al3Ti-Al2O3 Nano-composites Based on the Thermal Degradation of Aluminium Titanate & Facile Study on the Correlation between Microstructure & Their Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor)
Abstract
In this study insitu Al-Al3Ti-Al2O3 nanocomposite has been fabricated based on thermal decomposition of tialite (Al2TiO5) precursor in aluminium matrix through powder metallurgy method. Also the effect of high energy mechanical milling and hot extrusion on this procedure has been investigated. In the first step nano-structured tialite were synthesized through citrate sol gel methods. Then, different volume fraction of tialte was mixed with aluminium by high energy vibratory milling. The results of X-ray differaction analysis, scanning electron microscopy and differential thermal analysis showed that mechanical milling can degrade stability of tialite and cause strain-induced decomposition,...