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abdi--jafar
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Analyzing the Relationship Between Tehran and Dubai Stock Exchange
, M.Sc. Thesis Sharif University of Technology ; Keshavarz Haddad, Gholamreza (Supervisor)
Abstract
One of the obvious features of financial markets is the spread of crisis across the markets, which is called contagion and realized in forms of return and volatility spillover. Using the daily data on the stock price from December 2006 through June 2010, this study aims to examine the presence and significance of these spillovers between Tehran and Dubai Stock Exchange, by a FIVECM technique. The FIVECM provides long-run equilibrium relationships between the returns in the markets and short-run dynamics of involved endogenous variables. Furthermore, it takes into account presence of fractionality in the time series’ integration. Our analytical framework, models the spillover effects in...
Synthesis and Experimental Study of Organic-Metal Framework (MOF) Nanophotocatalists with Antibacterial Properties
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manouchehr (Supervisor) ; Abdi, Jafar (Co-Supervisor)
Abstract
MOFs are new class of materials that are used in different scientific fields because of their hybrid structure. In this project, focused on two specific applications, and aim is synthesis of a nanostructure which has antibacterial and photocatalytic activity. ZIF-8 because of its chemical and physical stability has been studied. For improving antibacterial influence and photocatalytic activity, silver nanoparticles are added to the structure. Magnetic nanoparticles covered by silica were used as core to facilitate separation process, ZIF-8 structure was constructed as shell on SiO2@Fe2O3 nano spheres. Magnetic nanoparticles improving stability of ZIF-8 in aqueous solutions. Synthetic nano...
Comments regarding: Pereira SA, Lopez M, Lavado N, Abreu JM, Silva H. A clinical risk prediction model of orthodontic-induced external apical root resorption. Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia Maxilofacial 2014;55(2):66-72
, Article Revista Portuguesa de Estomatologia, Medicina Dentaria e Cirurgia Maxilofacial ; Volume 56, Issue 3 , 2015 , Pages 141-142 ; 16462890 (ISSN) ; Sharif University of Technology
Elsevier Doyma
2015
Assessment of competitive dye removal using a reliable method
, Article Journal of Environmental Chemical Engineering ; Vol. 2, issue. 3 , September , 2014 , p. 1672-1683 ; Bastani, D ; Abdi, J ; Mahmoodi, N. M ; Shokrollahi, A ; Mohammadi, A. H ; Sharif University of Technology
2014
Abstract
In this study, a reliable and predictive model namely, least-squares support vector machine (LS-SVM) was developed to predict dye removal efficiency. Four LS-SVM models have been developed and tested using more than 630 series of experimental data which were obtained from our previous paper. These data consist of adsorbate type, adsorbent dosage, initial dye concentration, salt, absorbance time and dye removal efficiency. Direct Red 31 (DR31), Direct Green 6 (DG6) and Acid Blue (AB92) were used as a model dyes. The results show that the developed model is more accurate and reliable with the average absolute relative deviation of 0.678%, 0.877%, 0.581% and 0.978% for single systems and...
Risk Breakdown Structure (RBS) Identification and Designing for projects
, M.Sc. Thesis Sharif University of Technology ; Sepehri, Mehran (Supervisor)
Abstract
To actualize and making the outputs of a project effectual, it is necessary to conduct an effective management during a project. This case may not be possible without accurately planning for activities, management and controlling all phases of a project ignoring the risk management of that project. If risks of a project cannot be detected before conducting a project, it is possible to challenge the performance and even effectiveness of the project. In current conditions, the most important problem of managers and executives of construction projects through the country is risk management of projects, not acknowledging with definitions of risk, models of risk management and lack of a model for...
Entanglement and Decoherence in Optomechanical Systems Coupled through Photothermal Effects
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor)
Abstract
Optomechanical systems have attracted considerable attention in the last decade. Such a raising prominence is mainly due to its capability in providing new insight into the quantum behavior of macroscopic objects and exploring the interface between quantum and classical mechanics. Alongside this fundamental quest, cavity optomechanics has many other benefits, ranging from very precise measurements on forces and positions to quantum information processing. In this thesis, we investigate quantum properties of such systems. Particularly, we study cooling of the mechanical resonator toward its ground state and the entanglement between this mechanical resonator and the cavity field. Cooling the...
High Speed CDMA Communication in Optical Network on Chip
, M.Sc. Thesis Sharif University of Technology ; Hesabi, Shahin (Supervisor)
Abstract
As the number of processing cores on a single chip continues to grow, the need for a high band width, low power communication structure, will be the most important requirements of next generation chip multiprocessors. Today, a major part of power consumption in multi core architectures belongs to interconnects. Due to these facts, reducing consuming power, as well as supporting high performance, is concerned in these architectures. The concept of “network-on-chip” emerged to improve the performance of CMPs. But now a day, considering the circumstances of power budges, it’s incapable of presenting new strategies to decrease consuming power and delay. However, optical interconnects have the...
Clustering Data Streams using Core-Sets
, M.Sc. Thesis Sharif University of Technology ; Zarei, Alireza (Supervisor)
Abstract
We design a new algorithm for clustering data streams in any fixed di- mension, that use the framework of core-set to summarize data, in order to reduce the complexity of computation. Clustering is to separate data into distinct sets called clusters, which objects in the same cluster has the most similarity and objects in the different clusters has the least similarity.This problem has many application in the areas such as: machine learning,image processing, financial and stock transactions. Data stream has recently emerged as an important concept because in many applications, data is inherently streaming over a network or the data base is extremely large and sequential access is way faster...
Some Problems and Methods on Tournaments
, M.Sc. Thesis Sharif University of Technology ; Mahmoudian, Ebadollah (Supervisor)
Abstract
In 1953, Landau expressed the conditions for the existence of tournaments with a prescribed score vector R. Eleven years later, Ryser proposed an algorithm for constructing the tournament matrix with score vector R and showed that any two tournaments with the same score vector can be obtained from one another by a sequence of 3-cycle switches. Last year (2014) Brualdi and Fristcher explained in an article, similar to this process, the existence of, algorithm and switches for loopy tournament and Hankel tournament and similar structure skew-Hankel tournament. This paper is discussed in a chapter of this thesis. In 1991, De Caen found a lower bound for the real rank of a tournament matrix....
An Investigation on the Role of Metal-Organic Framework (MOF) on the Network Structure and Physical/Mechanical Properties of EPDM Rubber
, M.Sc. Thesis Sharif University of Technology ; Molvai, Hossein (Supervisor)
Abstract
Ethylene-propylene-diene monomer rubber (EPDM) is one of the elastomers that shows non-polar behavior, high elasticity at low temperatures, excellent thermal and ozone resistance, and high electrical resistance. In this respect, it is used in various applications such as sealing materials, conveyor belts, waterproof materials, cables, etc. One of the most important applications of this rubber is its use as a sealing material. In this case, the resilience behavior plays an important role in the sealing behavior of the EPDM rubber. Especially in cases such as the car's hydraulic braking system where high service temperatures and dynamic stresses are applied, resilience behavior will be more...
Fabrication of Porous Electrospun Fibe on Biocompatible Polymers such as Polycaprolactone (Pcl) and Thrs Based eir Application in Sample Preparation
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
The aim of this study was to develop a method to determine the trace residual amounts of nonsteroidal anti-inflammatory drugs in meat-related samples and to study the effect of different cooking methods and storage conditions of meat before cooking as an effective factor on the fate of these drugs. To proceed this goal, a nanocomposite was prepared from polycaprolactone nanofiber/silica mesopores as green sorbent by electrospinning. The synthesized nanocomposite was implemented for micro-solid phase extraction of the desired drugs in conjunction with high performance liquid chromatography. Polycaprolactone, due to its excellent physical properties, availability, biodegradability,...
Condition Monitoring of the DC-link Capacitor in Back-to-back Converter Using Main Transient Parameters
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
Condition monitoring of a system refers to the process of measuring and analyzing the aging indicators of critical components of a system that can be harnessed to estimate the system’s health. One of the main interests in condition monitoring is to performing the scheduled maintenance activities for the system. Monitoring the status of the system reduces maintenance costs and prevents unwanted contingencies and outages in the system.
In power electronics, the capacitors are the most critical components of the system from the point of reliability. Capacitors are the leading cause of failure in the power electronic converters so, this essay attempts to attain a solution to monitor the...
In power electronics, the capacitors are the most critical components of the system from the point of reliability. Capacitors are the leading cause of failure in the power electronic converters so, this essay attempts to attain a solution to monitor the...
On the design of fir optimum orthonormal filter banks
, Article 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05, Philadelphia, PA, 18 March 2005 through 23 March 2005 ; Volume IV , 2005 , Pages 545-548 ; 15206149 (ISSN); 0780388747 (ISBN); 9780780388741 (ISBN) ; Nayebi, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2005
Abstract
The problem of designing optimum filter banks for different applications is a popular research subject. It has also been shown that principal component filter banks (PCFB) are the optimum filter bank for many application. Existing methods to design FIR PCFBs are based on designing energy compaction filters. In this work we concentrate on designing FIR PCFB with the same frequency response as the ideal one. The presented approach results in filter banks with a very good approximation of ideal PCFB, as verified by simulations. © 2005 IEEE
A Heart-On-A-Chip Platform Containing Channeled Hydrogel for Drug Testing
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor)
Abstract
Cardiovascular diseases are one of the leading causes of death worldwide. Despite significant advances in therapeutic interventions for these diseases, the pathophysiology remains incompletely understood. Challenges in drug evaluation include the lack of appropriate clinical trials, such as conventional 2D cell cultures and animal studies, as well as the absence of model systems that can provide complex and patient-specific cardiac functions for diagnosis. Organ-on-a-chip devices have the potential to mimic the body's response to treatments by utilizing microscale cell culture fluid connections and creating realistic models of human organs of interest. Our objective is to develop a...
Scaffold Design and Fabrication for Retinal Tissue Engineering
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor)
Abstract
The retina, a photosensitive area in the central nervous system, is delicate and intricate. It is susceptible to degenerative disorders such as age-related macular degeneration (AMD), retinitis pigmentosa (RP), Stargardt disease (SD), and glaucoma. These diseases can lead to severe vision loss and ultimately irreversible blindness by causing destruction or dysfunction of different types of retinal cells. Unfortunately, there are no proven treatment strategies to cure or reverse these degenerative disorders. However, cell transplantation therapies may be an alternative to replace distorted cells and improve an individual's vision. Recent clinical outcomes show that transplanted cells in the...
Control of Swarm Micro-Swimmers in the Low-Reynolds Number Fluid to Reduce Energy Consumption
, M.Sc. Thesis Sharif University of Technology ; Nejat, Hossein (Supervisor)
Abstract
In this study, at first modeling of a self-propelled microrobot and its hydrodynamic effects on flow field are investigated. Then, a cascade controller has been designed for the fully actuated microrobot in order to track the desired time trajectories. Next, in order to design an optimal controller to decrease energy consumption, regardless of tracking the desired orientation trajectory compared to the desired position trajectory, the fully actuated microrobot would change to over actuated microrobot. Thus, it would be able to orient freely itself according to the flow field so that reduce the energy consumption. By applying the optimal controller on the over actuated microrobot, it was...
Evaluation and Diagnosis of Intraosseos Lesions in Panoramic Radiographs
, M.Sc. Thesis Sharif University of Technology ; Kasaie, Shohre (Supervisor)
Abstract
Panoramic radiography is known to be one of the preliminary means in diagnoses of maxillofacial intraosseos lesions, which has a big role in increasing the prognosis of such patients. Considering the fact that nowadays most health-care centers are equipped with digital radiography systems, we can rely on image processing techniques to recognize such lesions automatically.In this study, we try to segment mandible (lower jaw) out of panoramic image by means of some innovative algorithms based on edge detection and edge following, and some atlas-based methods. Then by extracting some features such as intensity, homogeneity, local energy and local gradient and with the help of SVM classifier we...
Cavity-mediated stationary atom-mirror entanglement in the presence of photothermal effects
, Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 376, Issue 45 , 2012 , Pages 2955-2961 ; 03759601 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
2012
Abstract
We study stationary entanglement properties of an optomechanical system containing an atomic ensemble. We focus onto the case of the movable mirror strongly coupled to the cavity field through both radiation pressure and photothermal force. Exploiting a quantum Langevin equation approach we investigate the bipartite entanglement properties of various bipartite subsystems as well as stationary tripartite entanglement of the system. We particularly study robustness of the atom-mirror entanglement against temperature. We show that, even though the photothermal force is a dissipative force, it can significantly improve the cavity mediated atom-mirror entanglement
Improving the optomechanical entanglement and cooling by photothermal force
, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 85, Issue 6 , 2012 ; 10502947 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
2012
Abstract
Cooling and entanglement in optomechanical systems coupled through radiation pressure and photothermal force are studied. To develop the photothermal model, we derive an expression for deformation constant of the force. By exploiting linearized quantum Langevin equations, we investigate the dynamics of such systems. According to our analysis, in addition to separate action of radiation pressure and photothermal force, their cross-correlation effect plays an important role in the dynamics of the system. We also achieve an exact relation for the phonon number of the mechanical resonator in such systems, and then we derive an analytical expression for it at the weak-coupling limit. At the...
Effect of higher-order waves in parametric oscillatory instability in optical cavities
, Article Physica Scripta ; Volume 83, Issue 4 , 2011 ; 00318949 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
2011
Abstract
A new strict proposal for determining radiation pressure coupling to optical resonator devices has been developed. Our evidence shows that the effect of the anti-Stokes wave cannot be neglected. It is shown that Stokes and anti-Stokes frequencies of all orders will participate in the optomechanical effect. Furthermore, we have shown that for the input pump power, there exists a threshold value for instability behavior. Radiation pressure can couple mechanical modes of a cavity to its optical modes, leading to parametric oscillation instability. Here we present an approximate analysis of such a nonlinear effect with Hamilton's least action principle. Loss in every mode has been taken into...