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mousavi--hossein
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Characteristics of Stocks that Frequently Hit Price Limits: Empirical Evidence from Tehran Stock Exchange (TSE)
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Vesal, Mohammad (Co-Advisor)
Abstract
Price limits are boundaries established by market regulators to confine daily movements of security prices within a predetermined price range. In this study, we have used the data of trades of all companies listed in the Tehran Stock Exchange during the years 1385-1393 to study the characteristics of stocks that hit price limits repeatedly using a panel regression model with fixed effects and the generalized method of moments (GMM). In fact, this study aims at investigating the price limits in Tehran Stock Exchange by a novel and distinct approach. In general, risky stocks exhibit more price volatility and thus are more likely to experience price-limit hits. In summary, the results reveal...
Statistical Analysis of Surface Hardness for Determination of Residual Stresses
, M.Sc. Thesis Sharif University of Technology ; Hossein Farrahi, Gholam (Supervisor) ; Faghidian, Ali (Co-Advisor)
Abstract
Residual stresses are stress fields that exist in the absence of any external loads. All mechanical processes can cause deformation that may lead to residual stresses. It is well established that virtually no material, no component and no structure of technical importance exists free of residual stresses. However, in practice, the knowledge of the true distribution of exiting residual stress is rare. The residual stress fields are very challenging to evaluate, independent of the measurement techniques. The important aspect about the residual stress determination is that often true distribution is unknown in the engineering specimen. A simple and non-destructive method to measure residual...
Chemical Adjustment of Membrane Surface to Reduce Fouling in Membrane Bioreactors
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
In this study, modification of Polyvinylidene fluoride membrane in order to reduce membrane fouling in membrane bioreactors is investiged. To achieve this goal, chemical modification and grafting methods were used. Initially, by chemical modification, the reaction was made to make hydroxyl groups on the membrane surface. The hydroxyl functional groups were used as a site for connecting of subsequent monomers. Finally, the lysozyme enzyme was used as the main modifier to improve the hydrophilicity and antibacterial properties of the membrane surface. To evaluate the performance of the modified membrane in comparison with the pristine membrane, different tests, such as water contact angle...
Improvement of performance and fouling resistance of polyamide reverse osmosis membranes using acrylamide and TiO2 nanoparticles under UV irradiation for water desalination
, Article Journal of Applied Polymer Science ; Volume 137, Issue 11 , 2020 ; Bastani, D ; Mousavi, S. A ; Heydari, H ; Vaghar Mousavi, D ; Sharif University of Technology
John Wiley and Sons Inc
2020
Abstract
The purpose of this research is to explain the surface modification of fabricated polyamide reverse osmosis (RO) membranes using UV-initiated graft polymerization at different irradiation times (15, 30, 60, and 90 s) and various acrylamide concentrations (10, 20, and 30 g L−1). Also, coating of membranes surface with various concentrations of TiO2 nanoparticles (10, 20, 30, and 50 ppm) followed by the same UV irradiation times was investigated. After that, the membranes modification was done by grafting of acrylamide blended with TiO2 nanoparticles via UV irradiation. The characterization of membranes surface properties and their performance were systematically carried out. The results...
General noise considerations of amplified photons in lightwave systems with optically bistable elements
, Article Proceedings - 10th International Conference on Laser and Fiber-Optical Networks Modeling, LFNM 2010, 12 September 2010 through 14 September 2010 ; 2010 , Pages 93-95 ; 9781424469970 (ISBN) ; Naqavi, A ; Mehrany, K ; Mousavi, S. M ; Aliakbar, J ; Mousavi, S. M ; Sharif University of Technology
2010
Abstract
An optical amplifier followed by a bistable element has been statistically analyzed before [1]. In this manuscript, output noise analysis represents, then signal to noise ratios (SNR) are calculated either for input or output. It will be shown that noise reduction, can be achieved by a proper selection of parameters
Design and assessment of variable-structure LQG PID multivariable controllers
, Article Optimal Control Applications and Methods ; 2016 ; 01432087 (ISSN) ; Nobakhti, A ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that...
Design and assessment of variable-structure LQG PID multivariable controllers
, Article Optimal Control Applications and Methods ; Volume 38, Issue 4 , 2017 , Pages 634-652 ; 01432087 (ISSN) ; Nobakhti, A ; Sharif University of Technology
John Wiley and Sons Ltd
2017
Abstract
Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that...
Challenges in using peer-to-peer structures in order to design a large-scale web search engine
, Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 461-468 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) ; Movaghar, A ; Sharif University of Technology
2008
Abstract
One of the distributed solutions for scaling Web Search Engines (WSEs) may be peer-to-peer (P2P) structures. P2P structures are successfully being used in many systems with lower cost than ordinary distributed solutions. However, the fact that they can also be beneficial for large-scale WSEs is still a controversial subject. In this paper, we introduce challenges in using P2P structures to design a large-scale WSE. Considering different types of P2P systems, we introduce possible P2P models for this purpose. Using some quantitative evaluation, we compare these models from different aspects to find out which one is the best in order to construct a large-scale WSE. Our studies indicate that...
Optimized U-shape convolutional neural network with a novel training strategy for segmentation of concrete cracks
, Article Structural Health Monitoring ; 2022 ; 14759217 (ISSN) ; Bakhshi, A ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Crack detection is a vital component of structural health monitoring. Several computer vision-based studies have been proposed to conduct crack detection on concrete surfaces, but most cases have difficulties in detecting fine cracks. This study proposes a deep learning-based model for automatic crack detection on the concrete surface. Our proposed model is an encoder–decoder model which uses EfficientNet-B7 as the encoder and U-Net’s modified expansion path as the decoder. To overcome the challenges in the detection of fine cracks, we trained our model with a new training strategy on images extracted from an open-access dataset and achieved a 96.98% F1 score for unseen test data. Moreover,...
Optimized U-shape convolutional neural network with a novel training strategy for segmentation of concrete cracks
, Article Structural Health Monitoring ; Volume 22, Issue 2 , 2023 , Pages 1211-1224 ; 14759217 (ISSN) ; Bakhshi, A ; Sharif University of Technology
SAGE Publications Ltd
2023
Abstract
Crack detection is a vital component of structural health monitoring. Several computer vision-based studies have been proposed to conduct crack detection on concrete surfaces, but most cases have difficulties in detecting fine cracks. This study proposes a deep learning-based model for automatic crack detection on the concrete surface. Our proposed model is an encoder–decoder model which uses EfficientNet-B7 as the encoder and U-Net’s modified expansion path as the decoder. To overcome the challenges in the detection of fine cracks, we trained our model with a new training strategy on images extracted from an open-access dataset and achieved a 96.98% F1 score for unseen test data. Moreover,...
Feasibility And Study(CNG Cylinder Production Plant)
, M.Sc. Thesis Sharif University of Technology ; Haji, Alireza (Supervisor)
Abstract
Nowadays best using of fossil fuels sources of the country (and) importance of comparison against lack of capacity in petrol production make determined the programmers and the directors to foresee and design expanded programs of the goals, to use natural gas for car fuels. To reach fulfillment of these programs, the confirmed needs of the natural gas cylinders are improved and make it essential to invest on producing compressive natural gas cylinders. In this way economical and technical change researches has been done in order to construct on department to produce 200,000 compressive natural gas cylinders in a year during two sets.(shifts) According to the results of technical researches...
Numerical Simulation of Forced Impregnation in a Thick Capillary Tube
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor)
Abstract
Drop penetration into the capillary tube, as a classical problem, has been studied over 100 years. But there are a few studies that investigate forced impregnation of capillary tubes, which has major application in coating, inkjet printing and rain drop penetration into the soil, have been made. A comprehensive numerical investigation on millimeter droplet impact dynamics on a thick capillary tube with micrometer sized pore is conducted and validated against experimental data. This work is extended to oblique impact of drops into pores and normal impact on nanoscaled pores. We apply the finite volume numerical method to solve the time-dependent governing equations of continuity, momentum in...
Investigation of Dynamic Response of Shallow Foundations on Layered Soil Medium by Physical Modeling
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Dynamic impedance functions method is most recent approach in the analysis of soil-foundation dynamic interaction, and presented for massless rigid foundations. Impedance functions are frequency dependent functions, and used to obtain dynamic response of foundation with arbitrary mass subjected to dynamic loading of any frequency and magnitude. The important assumptions for appropriate useof mentioned method are rigidity of foundation and visco-elastic behavior of the soil beneath the foundation. In this study, experimental vertical impedance functions of square and circular foundations have been investigated,using physical modeling tests. A granular soil layer with finite thickness...
Optimal Investment Strategies in Discrete-Time With Access to Derivatives
,
M.Sc. Thesis
Sharif University of Technology
;
Kianfar, Farhad
(Supervisor)
Abstract
Optimal investment strategies are often derived in continuous time models, but have to be implemented in discrete time. It has been shown that in models with stochastic volatility or jumps; this could lead to significant utility loss, for an investor who utilizes ‘Derivatives’ in his/her portfolio. In this study, we determine the optimal investment strategies with discrete trading explicitly taken into account, through ‘Stochastic Dynamic Programming’. These strategies are in the form of optimal factor exposures for portfolio. The investor, then, needs to use sufficient non-redundant Derivatives in addition to the ‘Stock’ to gain the desired exposures in each point of state space he meet....
Design and Implementation of 7-10 GHz CMOS Phase Shifter
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Phased array systems which are used for sending and receiving electromagnetic signals in mandatory directions are widely used in today’s wireless communication, satellite communication, and radar systems. Phased array systems are composed of units called transmitter/ receiver (TR) modules. These units are connected to antennas in one end and to the combiner/divider at the other end and are playing a major role in determining the quality of phased arrays. Transmitter/Receiver units include a phase shifting circuit for controlling the phase and an attenuator circuit for amplitude control of the signal being sent or received, solid state switches and a number of amplifiers. The aim of this...
The Prediction Branching Polypropylene Monte Carlo Method
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor)
Abstract
Linear structure of polypropylene, which is a direct result of Ziegler-Natta catalysts, led to the melt strength of the polymer is low and it does not show hardness strain. This defect is cause to the use of polypropylene in some processes, such as thermoforming, making foam etc. are limited. A main methods to solve this defect are branching structure of the polymer. There are three general methods for this purpose, which are modified by chemical, electron beam irradiation and polymerization in the presence of metallocene catalyst. The first two methods that past processing, polypropylene branching using linear type is produced, while the third method branching occurs during polymerization....
Designing a Vehicle Counting and Classification System
, M.Sc. Thesis Sharif University of Technology ; Gholampour, Iman (Supervisor)
Abstract
In recent years, Intelligent Transportation Systems (ITS) have received special attentions both in research and in commercial areas. Increased infrastructure facilities, like surveillance cameras, has made this concept even more attainable than before. In this respect, the ability to automatically extract information from traffic images, as one of the key inputs of ITSs, is of great importance. With an increased number of surveillance cameras and the need for more accurate information regarding the road users and their interactions, in order to better city traffic management, building and repairing roads, trip time estimation, number of people per roads estimation and etc, using human...
Modeling and Dynamic Analysis of a Laboratary Prototyped Rotary MR Damper using a Prosthetic Knee
, Ph.D. Dissertation Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
Regaining biomechanical function, comfort and quality of every-day life is a prime consideration when designing prosthetic devices for amputees. The magnetorheological (MR) prosthetic knee, which is the subject of this study, is an example of such a device. The study presents a comprehensive and a combined MR device design and MR fluid design approach, aiming to advance the MR prosthetic knee. First, this study focuses on developing a new configuration on magnetorheological (MR) brake damper as prosthetic knee. The new configuration is a rotary damper using MR fluid with a single rotary disc will act as a brake while MR fluid is activated by magnetic field in different walking gait. The main...
Total Cost Reduction for Big Data Processing by Smart VM Storage Selection and Data Placement
, M.Sc. Thesis Sharif University of Technology ; Goudarzi, Maziyar (Supervisor)
Abstract
The fastest growing of data in the fields of economic, cultural and scientific quick analysis of this data is one of the needs of users. The inability of the traditional programming model for processing large data makes MapReduce programming model to be introduced. MapReduce model, processing big data in shorter time available. Users to analyze large data processing, rent necessary resources from infrastructure of cloud as one of the most popular are provided. Due to cloud resources acquired and run-time program on selected configurations, the cost of these resources are paid according to their use. So if resources are not proportionate with the needs of the program will be wasting money and...
Study of Heat Transfer in Car
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor)
Abstract
Optimization of heat transfer in vehicle's underhood which contains radiator, cylidir block, cylinder head and … with minimum pressure loss on engine is one of the most important problems of the car companies in all over the world.To design some cooling parts like simple radiators which doesn’t have a effective cooling effect, we can use equations.but for more complicated geometries which is morte efficient we have many complicated solutions.So in this condition computationl analysis and laboratories play an important role.in this condition we should consider that producing a sample and the process of verifying the result of test is too expensive.So recently the car companies prefare...