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zamani-dehkordi--payam
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Total 458 records
Data Mining Approach for Fault Diagnosis of Power Systemby Wide Area Measurement
, M.Sc. Thesis Sharif University of Technology ; Ranjbar, AliMohammad (Supervisor)
Abstract
Fast and accurate fault diagnosis has a significant role in the power system operation. For a power system to come back to the normal state, the precise fault diagnosis is necessary. The current practice in power system fault diagnosis needs operators in the control center to use data of PR and CB in order to infer the faulted section based on their experiences. Expert systems and artificial intelligence have been suggested as alternatives to the human expert experience and inference. Other model- and optimization-based methods have also been reported for fault diagnosis, provided that similar data is available from the SCADA system.Nevertheless, in large disturbances resulting in partial or...
Analysis and Study the Effect of Knowledge Management Implementation on Productivity Case Study: Tehran Regional Electric Company
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
The successful development and implementation of a knowledge management system requires principles and instructions compatible with the organization. In the absence of essential and domestic components of a given organization, the process of knowledge management implementation will fail to be successfully completed. There are now various models for the implementation of knowledge management; however, these models only recommend general strategic guidelines, hardly offering any specific strategic plans as to how organizations can successfully and effectively implement knowledge management. Since the promotion of productivity is the ultimate goal of knowledge management, the present research...
Coordinated Scheduling of Power and Natural Gas Systems Considering Demand Uncertainty
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
The everyday increasing electricity consumption of household and industrial sectors across the world, and also the limited generation capacity and fuel supplies has led electricity companies, whether in private or government sectors, to focus deliberately on power generation planning, its costs, risks and constraints Because of many reasons including high efficiency, low cost of capital investment, expeditious permitting, and operation flexibility of gas-fired generating units, electricity companies prefer them to old ones like coal-fired or oil-fired generating units. Thus natural gas has gained a significant share in the portfolio of electricity generation fuel resources, and it is...
Robust DTC control of doubly-Fed induction machines based on input-output feedback linearization using recurrent neural networks
, Article Journal of Power Electronics ; Volume 11, Issue 5 , 2011 , Pages 719-725 ; 15982092 (ISSN) ; Hashemnia, M. N ; Faiz, J ; Sharif University of Technology
2011
Abstract
This paper describes a novel Direct Torque Control (DTC) method for adjustable speed Doubly-Fed Induction Machine (DFIM) drives which is supplied by a two-level Space Vector Modulation (SVM) voltage source inverter (DTC-SVM) in the rotor circuit. The inverter reference voltage vector is obtained by using input-output feedback linearization control and a DFIM model in the stator a-b axes reference frame with stator currents and rotor fluxes as state variables. Moreover, to make this nonlinear controller stable and robust to most varying electrical parameter uncertainties, a two layer recurrent Artificial Neural Network (ANN) is used to estimate a certain function which shows the machine...
Alginate/PVP/Pomegranate Seed Hydrogels as Bio-sorbents of Water Pollutants
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Mollaabasi, Payam (Co-Supervisor)
Abstract
In the past decades, hydrogels have been used as an adsorbent with high potential to remove pollutants in water. Hydrogels are three-dimensional polymer networks that have the ability to absorb and store water and water-soluble compounds due to the presence of hydrophilic functional groups in their structure. Different particles with unique characteristics can be used to increase the efficiency of hydrogel absorption. Based on the type of pollutant, hydrogels are divided into three different forms, including particles, films and nanocomposites. In this research, the absorption effect of metal cations as well as the absorption kinetics of polyvinyl pyrrolidine-based hydrogels, sodium...
The Effect of Olive Leaf Green Inhibitor on the Corrosion Resistance of Steel Reinforcement in Geopolymer Concrete Pore Solution
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Hosseini, Payam (Co-Supervisor)
Abstract
In this research project, the aim was to investigate the potential of olive leaf extract as an eco-friendly inhibitor for enhancing the corrosion resistance of reinforcing steel in simulated geopolymer concrete pore solution (GCP) containing chloride ions. The inhibitory effects of olive leaf extract were evaluated using various electrochemical techniques as well as scanning electron microscopy. The main phenolic compounds present in olive leaf extract were identified using high performance liquid chromatography (HPLC). Moreover, the elements and chemical bonds present in the surface passive film of the steel bar immersed in the olive leaf inhibiting system were characterized using...
Iran’s oil development scenarios by 2025 [electronic resource]
, Article Energy Policy ; Volume 56, May 2013, Pages 612-622 ; Sharif University of TechnologyDynamic Simulation and Control of Reactive Systems Involving Metabolic Pathways
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehry Bozarjomehry, Ramin (Supervisor) ; Setoodeh, Payam (Co-Supervisor)
Abstract
In this project, modeling, simulation, and control of the Saccharomyces Cerevisiae were studied. In the first section, simulation and control of a structural model of saccharomyces Cerevisiae were performed. Fuzzy Logic Controller (FLC) as a model-independent controller and Global Linearization Controller (GLC) as a model-based controller were designed. Additionally, two types of Kalman filters were designed to predict all states of the structural model: 1-Extended Kalman Filter (EKF), 2- Unscented Kalman Filter (UKF). As a concise explanation, the control action of the GLC is a function of all states of the model, and since that measuring all metabolites is not practical, the EKF and UKF...
Reaction-diffusion equations with polynomial drifts driven by fractional brownian motions
, Article Stochastic Analysis and Applications ; Volume 28, Issue 6 , Oct , 2010 , Pages 1020-1039 ; 07362994 (ISSN) ; Sharif University of Technology
2010
Abstract
A reaction-diffusion equation on [0, 1]d with the heat conductivity k > 0, a polynomial drift term and an additive noise, fractional in time with H > 1/2, and colored in space, is considered. We have shown the existence, uniqueness and uniform boundedness of solution with respect to k Also we show that if k tends to infinity, then the corresponding solutions of the equation converge to a process satisfying a stochastic ordinary differential equation
Hour-ahead demand forecasting in smart grid using support vector regression (SVR)
, Article International Transactions on Electrical Energy Systems ; Vol. 24, issue. 12 , 2014 , p. 1650-1663 ; Fereidunian A ; Gholami-Dehkordi H ; Lesani H ; Sharif University of Technology
2014
Abstract
Demand forecasting plays an important role as a decision support tool in power system management, especially in smart grid and liberalized power market. In this paper, a demand forecasting method is presented by using support vector regression (SVR). The proposed method is applied to practical hourly data of the Greater Tehran Electricity Distribution Company. The SVR parameters are selected by using a grid optimization process and an investigation on different kernel functions. Moreover, correlation analysis is used to find exogenous variables. Acceptable accuracy of load prediction is shown by comparing the result of SVR model to that of the artificial neural networks and the actual data,...
New method of determination for pressure and shear frictions in the ring rolling process as analytical function
, Article Journal of Solid Mechanics ; Vol. 6, issue. 3 , 2014 , pp. 322-333 ; ISSN: 20083505 ; Sharif University of Technology
2014
Abstract
Ring rolling is one of the most significant methods for producing rings with highly precise dimensions and superior qualities such as high strength uniformity, all accomplished without wasting any materials. In this article, we have achieved analytical formulas for calculating the pressure and shear friction over the contact arcs between the rollers and ring in the ring rolling process for the material in general nonlinear hardening property. We have also asserted the best mathematical model to predict friction for rolling processes. The method we use is based on calculating the analytical stress distribution. In other words, by using of Saint-Venan principal the stress components are...
Assessing new conditions for secretary problem using Multi-Agent Systems
, Article 13th Iranian Conference on Fuzzy Systems, IFSC 2013 ; August , 2013 , Page(s): 1 - 4 ; ISBN: 978147991227-8 ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
The secretary problems are of types of the optimal stopping theory problems and are also distinguished as well known problems in applied probability, statistics and decision theory fields. The importance of these kinds of problems defines many new conditions which have been discussed till now. The significance of these types of problems in social issues causes to define many conditions which are vastly discussed. In this paper, a new condition of this problem is considered. These conditions which have been performed using a real time method are based on Multi-Agent Systems techniques. In this paper, after evaluating this method, the resulted answers are examined using Multi-Agent system...
Novel type of two-impinging-jets reactor for solid-liquid enzyme reactions
, Article AIChE Journal ; Volume 52, Issue 2 , 2006 , Pages 692-704 ; 00011541 (ISSN) ; Sharif University of Technology
2006
Abstract
The isomerization of D-glucose to D-fructose using the immobilized glucose isomerase, as a typical model system of solid-liquid enzyme reactions has been carried out in a novel type of two-impinging-jets reactor (TIJR), which is characterized by a rotating inner cylinder in a stationary one. Because of the impinging process, turbulence, and complex trajectory of the solid particles within the reactor, the fractional conversion of glucose obtained in the TIJR increased dramatically compared to that obtained by conventional reaction systems. A compartment model was considered to describe the pattern of flow [residence time distribution (RTD) of solid particles] within the TIJR. Considering...
Sparse array design for millimeter-wave imaging
, Article 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings, 26 June 2016 through 1 July 2016 ; 2016 , Pages 1039-1040 ; 9781509028863 (ISBN) ; Fakharzadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, the design of an efficient sparse array, used to reconstruct the image from millimeter-wave signals, is presented. The proposed array takes advantage of the sparsity concept of the image in the spatial Fourier domain to reduce the number of array elements such that the beam pattern of the designed array meets the desired beamwidth and sidelobe level. Simulation and measured results confirm the effectiveness of the proposed design on high-quality reconstruction of the image, while 85% reduction in the number of elements is achieved as well as the reduction in scan time and system complexity
A feature fusion based localized multiple kernel learning system for real world image classification
, Article Eurasip Journal on Image and Video Processing ; Volume 2017, Issue 1 , 2017 ; 16875176 (ISSN) ; Jamzad, M ; Sharif University of Technology
2017
Abstract
Real-world image classification, which aims to determine the semantic class of un-labeled images, is a challenging task. In this paper, we focus on two challenges of image classification and propose a method to address both of them simultaneously. The first challenge is that representing images by heterogeneous features, such as color, shape and texture, helps to provide better classification accuracy. The second challenge comes from dissimilarities in the visual appearance of images from the same class (intra class variance) and similarities between images from different classes (inter class relationship). In addition to these two challenges, we should note that the feature space of...
1.5-D sparse array for millimeter-wave imaging based on compressive sensing techniques
, Article IEEE Transactions on Antennas and Propagation ; Volume 66, Issue 4 , April , 2018 , Pages 2008-2015 ; 0018926X (ISSN) ; Fakharzadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The goal of this paper is to reduce the antenna count in a millimeter (mm)-wave imaging system by proposing both hardware and software solutions. The concept of image sparsity in the transform domain is utilized to present the compressive sensing (CS) formulation for both mono-static and multistatic imaging at mm-wave frequencies. To reduce the complexity of the imaging system and reconstruction process, we introduce 1.5-D array structure, which is a random sparse array with orthogonal element locations. It is shown that the peak signal-to-noise ratio (PSNR) of the reconstructed image obtained by a 1.5-D array with 65% sparsity is very close to the PSNR of a uniform 2-D array for mono-static...
An efficient strategy to overproduce glutamic acid in Corynebacterium glutamicum fermentation
, Article Scientia Iranica ; Volume 8, Issue 3 , 2001 , Pages 203-206 ; 10263098 (ISSN) ; Roostaazad, R ; Sharif University of Technology
Sharif University of Technology
2001
Abstract
In this paper, effect of penicillin addition in enhancing the secretion of glutamic acid by Corynebacterium glutamicum was studied. The proper time of adding penicillin to maximize glutamic acid production was found to drift at repeated trials. In contrast, maximum acid productivity was obtained when penicillin was injected at a proper biomass concentration of about 7.7 gram dry weight per lit (gdw/l). Moreover, rate of consumption of sugar and ammonia through the course of glutamic acid fermentation was monitored. In production phase, these two rates were correlated properly with a ratio of 3.2:1 which is comparable to the theoretical stoichiometric value of 5:1. Therefore, through feeding...
Credit Risk Analysis of a Bank's Loan Portfolio
, M.Sc. Thesis Sharif University of Technology ; Zamani, Shiva (Supervisor)
Abstract
Risk management is one of the most important topics in banking. Risk management in banking is divided to several categories including credit risk. Credit risk is also divided to individual credit risk and portfolio credit risk. In Iran many of banks have worked on individual credit risk models, but few of them have worked on portfolio models because these models have developed only in recent years. In our project we present three categories of credit risk models and then analyze the data of a private bank in Iran with CreditPortfolioView model. In CreditPortfolioView model, macroeconomic parameters are used to analyze the correlated behavior of individuals as a benchmark in different...
Project Finance and Motivations and Optimum Approach of Using it in LNG Industry of Iran
, M.Sc. Thesis Sharif University of Technology ; Zamani, Shiva (Supervisor)
Abstract
Project Finance is a novel approach in financing big projects. High debt ratio, independency to promoter credit and establishing a special purpose company, are some of project finance characteristics that could be very beneficial in some projects. Liquid Natural Gas (LNG) is a solution for exporting natural gas to far destination. As economical and environmental benefits of using natural gas have been increased in recent years, LNG industry has been experienced rapid growth. In this project we analyze project finance and then describe economical motivation of using this method in LNG industry of Iran.
Collapsible Behavior of Gorgan Loess Using Odeometer
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
In nature, there are types of soils that when goinging under stress at constant moisture, or increase of moisture at constant stress, or change of both characters, they show a sudden and high level decrease in their volume. These type of soils are named as Collapsible soils. Iran is one of the countries that at some parts of its land collapsible soils are found. In this research by using of laboratory equipments, the volume change behavior of collapsible loess soils of Gorgan plain (North of Iran) is evaluated under increase of water content and inundation stress. In these experiments, the usual odeometer cell has been used for exploring the behaviour of collapsibility and volume change of...