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    , M.Sc. Thesis Sharif University of Technology Mahmoodzadeh, Zahra (Author) ; Ehsan, Mehdi (Supervisor)
    Abstract
    Losses are unavoidable in any parts of power systems, from generation to receiving nodes and occur in transmission and distribution networks. However, the main loss component is produced in distribution networks. Energy losses in distribution networks are about 70% of technological transport energy losses.
    Energy losses in distribution networks are an important indicator for the planning and operation of the system. A fast, reliable and accurate energy loss calculation method is required for optimal operation of the distribution networks.
    Energy loss depends on network's operating conditions. Loads values and loads factors are time variables; therefore, methods based on probability... 

    The Effect of Government Ownership on Financial Structure: A Case Study of Sahamedalat in Iran

    , M.Sc. Thesis Sharif University of Technology Jafari, Mohammad Mahdi (Author) ; Mahmoodzadeh, Amineh (Supervisor)
    Abstract
    The distinction between SOEs and private firms in access to loans is essential from the viewpoint of policy-making. This distinction is more crucial when we know that the difference is caused by factors other than natural market forces and has emerged merely by government ownership. In this paper, we investigate a unique intervention in privatization and identify the causal effect of government ownership on access to loans. In this respect, we study Sahamedalat in Iran by using DID approach and estimate the effect of giving up the treatment firm's cashflow right on the amount and composition of the loans. The results show the intervention significantly decreases the long-term loan of the... 

    A framework for protecting privacy on mobile social networks

    , Article Mobile Networks and Applications ; Volume 26, Issue 3 , 2021 , Pages 1281-1299 ; 1383469X (ISSN) Safi, S. M ; Movaghar, A ; Safikhani Mahmoodzadeh, K ; Sharif University of Technology
    Springer  2021
    Abstract
    In recent years, mobile social networks have largely been developed and gained considerable popularity. An approach to protecting privacy on mobile social networks is the use of encryption and access control. Good alternatives for use on mobile social networks are the Public Broadcast Encryption approach for appropriate concordance and consistency with the structure of social networks as well as the Attribute-Based Encryption owing to its capability and proper implementation of the access control policy. Accordingly, in this paper, a framework was presented based on the Public Broadcast Encryption and Attribute-Based Encryption. Using proxies, we outsourced some of these operations in the... 

    Energy loss estimation in distribution networks using stochastic simulation

    , Article IEEE Power and Energy Society General Meeting, 26 July 2015 through 30 July 2015 ; Volume 2015-September , 2015 ; 19449925 (ISSN) ; 9781467380409 (ISBN) Mahmoodzadeh, Z ; Ghanbari, N ; Mehrizi Sani, A ; Ehsan, M ; Sharif University of Technology
    IEEE Computer Society  2015
    Abstract
    This paper presents an improved stochastic simulation method for calculating current dependent energy losses in distribution networks. The method is based on power load curves and integrates the stochastic nature of the load curves with power and voltage covariance matrices. The method reduces calculation effort using the factor analysis of covariance matrices and provides a few quantities needed to calculate energy losses. The method has no limitation for network configuration and gives accurate results several times faster than other existing methods. Therefore, it is appropriate for considering losses in optimization and decision making purposes in operating and planning of distribution... 

    Estimation of Bank Loan Interest Rate and Determining its Correlated Factors: A Case Study of Listed Companies in Iran

    , M.Sc. Thesis Sharif University of Technology Nateghi, Morteza (Author) ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
    Abstract
    Bank loans are one of the main sources of financing for enterprises and the most important source of financing for large enterprises in Iran. Uncertainty about future conditions and asymmetric information between the bank and the firm puts the provision of loans at risk. According to the principle of proportionality of risk and return, the interest rate of bank facilities should be proportional to the risk that the bank incurs in return for granting the loan. In general, the interest rate of bank loans can be affected by three types of risks: the credit risk of the applicant firm, the risk of the lender bank and the macroeconomic environment risk. In this study, we try to estimate the... 

    Conceptualization of a fresh groundwater lens influenced by climate change: A modeling study of an arid-region island in the Persian Gulf, Iran

    , Article Journal of Hydrology ; Vol. 519, issue. PA , 2014 , pp. 399-413 ; ISSN: 00221694 Mahmoodzadeh, D ; Ketabchi, H ; Ataie-Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
    2014
    Abstract
    Understanding the fresh groundwater lens (FGL) behavior and potential threat of climatic-induced seawater intrusion (SWI) are significant for the future water resources management of many small islands. In this paper, the FGL of Kish Island, an arid-region case in the Persian Gulf, Iran, is modeled using two-dimensional (2D) and three-dimensional (3D) simulations. These simulations are based on the application of SUTRA, a density-dependent groundwater numerical model. Also, the numerical model parameters are calibrated using PEST, an automated parameter estimation code. Firstly a detailed conceptualization of the FGL model is completed to understand the sensitivity of the FGL to some... 

    The Real Effect of Banks’ Money Creation Ability in a New Keynesian Framework

    , M.Sc. Thesis Sharif University of Technology Darzi Larijani, Samyar (Author) ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
    Abstract
    In much of the financial economics literature, banks are modeled as financial intermediaries that transfer household deposits to loan applicants. In these models, deposits are obtained from the accumulation of real amounts (household savings). In addition to this, another approach describes banks not as intermediaries of loanable funds, but as money-creators who do not need to accumulate deposit resources to lend. In this study, by modeling the money-creation behavior of the banking network, we try to answer the question that if the bank can create credit and purchasing power for the firm based on its future income, how will the general variables of the economy, including consumption and... 

    Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 Pourjavadi, A. (Ali) ; Mazaheri Tehrani, Zahra ; Sharif University of Technology
    Abstract
    A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5  

    Banks Money Creation and the Transmission Mechanism of Shocks

    , M.Sc. Thesis Sharif University of Technology Esfahani, Mohammad Reshad (Author) ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
    Abstract
    Banks are not only money brokers but also money creators. The ability of a bank to create money is due to its unique feature in issuing debts (deposits) that are accepted as a medium of exchange by economic agents. Although this bank function has been discussed under the "liquidity transformation" heading under the micro-banking literature, it has been less discussed in macro literature. In this study, we want to examine the consequences of the bank's liquidity transformation function by developing a New-Keynesian model in which banks can finance the economy by voluntarily expanding their balance sheet. To identify the mechanisms that the money creator bank creates in the model, we have... 

    Financial Contagion ,Interbank Market, and Central Bank Policy

    , M.Sc. Thesis Sharif University of Technology Rashidi Ravari, Pooya (Author) ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
    Abstract
    Financial distress can propagate through different channels such as bank run, deposit interbank market,networks and asset prices. In this paper, with the assumption of deposit insurance, no linkages between banks, no deposit interbank market and fixed asset prices, we show that asset-side shocks might propagate through both loan interbank market and deposit market. However, when there is aggregate liquidity surplus in the banking system, loan interbank market results in the first best allocation. In contrast, aggregate liquidity shortage does not result in optimum allocation. In the presence of deposit and loan interbank market, not only shocks propagate but also they are magnified with the... 

    The Impact of Exchange Rate Changes on Bank Lending: A Case Study of Iranian Banking System

    , M.Sc. Thesis Sharif University of Technology Hassanpour, Mohammad Reza (Author) ; Mahmoodzadeh, Amineh (Supervisor) ; Madanizadeh, Ali (Supervisor)
    Abstract
    We show evidence of a new mechanism in the lending channel via changes in the exchange rate on the loan supply. Changes in the relative risk or return of banks' balance-sheet items induced by exchange rate fluctuations can modify the level and composition of loans. Using a monthly panel of Iranian banks during 2007-2018, we find that a one percentage point increase in the exchange rate reduces loan supply by 0.05 percentage point. We consider this effect a sign of a change in the supply of loans since banks' responses to the exchange rate fluctuations differ depend on their health conditions. The impact is more remarkable for banks with higher illiquidity, non-performing loans, and foreign... 

    , M.Sc. Thesis Sharif University of Technology (Author) ; Mahmoodzadeh Ahmadi Nezhad, Amineh (Supervisor) ; Madanizadeh, Ali (Supervisor)
    Abstract
    This study seeks to identify the characteristics of pricing behavior in Iran's economy at the producer level. For the first time, this research utilizes Iranian producer price quote microdata from the industrial sector, which is used to construct the Producer Price Index (PPI). Using this new data, five facts about Iran's economy can be inferred: 1) On average, the frequency of price changes each quarter is about 52%, and the average implied duration of prices is 1.6 quarters. 2) There is no significant difference in the price stickiness between producer and consumer prices. 3) Firms' decisions to change or not change prices are more influenced by producer inflation, while their decisions on... 

    Theoretical and Computational Investigation of Quantum Plasmonic Properties of Nanocluster Dimers

    , M.Sc. Thesis Sharif University of Technology Mahmoudi, Erfan (Author) ; Jamshidi, Zahra (Supervisor)
    Abstract
    In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon... 

    Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation

    , M.Sc. Thesis Sharif University of Technology Hadi, Hossein (Author) ; Jamshidi, Zahra (Supervisor)
    Abstract
    Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic... 

    Investigation of Plasmonic Excitation in Carbonic Nanostructures Within Near-IR

    , M.Sc. Thesis Sharif University of Technology Madadi, Mahkam (Author) ; Jamshidi, Zahra (Supervisor)
    Abstract
    To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have... 

    Using Nonlinear Effects of Light for Optical Signal Processing

    , M.Sc. Thesis Sharif University of Technology Shatery, Farshid (Author) ; Kavehvash, Zahra (Supervisor)
    Abstract
    Ultrafast signal processing in time-domain with high resolution and reconfigura-bility is a challenging task. This paper, for the first time, introduces a time-varying metasurface consisting of graphene microribbon array for implementing time-lens in the terahertz domain. Given that the surface conductivity of graphene is proportional to the Fermi energy level in the THz regime, it is possible to change the phase property of the incident electromagnetic pulse by changing the Fermi level while the Fermi level itself is a function of voltage. Upon this fact, a quadratic temporal phase modulator, namely time-lens has been realized. This phase modulation is applied to the impinging signal in the... 

    Using Simulation-Optimization Approach for Fire Station Location and Vehicle Assignment Problem: a Case Study in Tehran, Iran

    , M.Sc. Thesis Sharif University of Technology Pirmohammadi, Ali (Author) ; Amini, Zahra (Supervisor)
    Abstract
    In this research, the problem of locating fire stations and allocating equipment has been studied and a simulation-optimization approach has been presented to solve the problem. The mathematical models of this research were developed based on the idea of the randomness of the covered demand and the maximum expected coverage model. In these models, the issue of non-availability of equipment to cover accidents, the random nature of accidents, various fire incidents and the equipment needed to cover them are considered. Two mathematical models with deterministic and non-deterministic approach with different scenarios for demand are proposed. The non-deterministic model is developed with the aim... 

    Introducing An Integrated Framework For Solving The Fleet Planning Problem Using A Simulation-Optimization Approach

    , M.Sc. Thesis Sharif University of Technology Sahebi, Armin (Author) ; Amini, Zahra (Supervisor)
    Abstract
    One of the main concerns of industrial companies’ managers is providing an efficient logistics system. To achieve an efficient logistics system, the fleet planning problem is studied by many researchers in recent years. This problem consists of multiple sub-problems at three levels: operational, tactical, and strategic. These sub-problems are closely related to each other and need to be studied and addressed in an integrated manner. In this research, an attempt is made to provide an integrated framework to solve the vehicle routing problem (operational), outsourcing problem (tactical), and fleet composition problem (strategic). These problems have various uncertainties, including customer... 

    Analytical Modelling and Optimization of Disk Type, Slot Less Resolver

    , M.Sc. Thesis Sharif University of Technology Moheyseni, Atefeh (Author) ; Nasiri Gheidari, Zahra (Supervisor)
    Abstract
    Resolvers, due to their robust structure, are widely used in automation systems. Among the types of resolvers, the accuracy of the Wound Rotor (WR) resolver in the occurrence of common mechanical errors is higher than other types of resolvers. therefore, in this thesis, an AFWRR is studied to improve the performance. Increasing the number of poles in WR resolvers is a good solution for increasing the accuracy of these electromagnetic position sensors. However, high-speed WR resolvers due to employing fractional slot windings suffer from rich sub-harmonics in the induced voltages. A common solution for suppressing the undesirable sub-harmonics is using multi-layer winding with appropriate... 

    A Survey on Searchable Symmetric Encryption Schemes

    , M.Sc. Thesis Sharif University of Technology Sajadieh, Zahra Sadat (Author) ; Khazaei, Shahram (Supervisor)
    Abstract
    Using “Searchable Encryption” enables us to encrypt the data, while preserving the possibility of running search queries. One of the most important applications of the mentioned is in Cloud Storage. As users do not trust the Cloud space, they are not inclined to store their data on the Could. The solution to this problem is of course, Cryptography. However, ordinary Cryptography methods, eliminate the data’s searchability. Hence, we need encryption schemes that code the data while retaining their searchability. So far, various schemes has been proposed that differ in their performance, security level, and usage. In this thesis, we aim to discuss and analyze these methods