Sharif Digital Repository

The main objective of this research is to predict the life of a bearing that works in variable speed working condition. In this project, two series of experiments were conducted to investigate the vibration of the bearings. In the first series of experiments, multiple imperfections have been created on parts of the bearing that are susceptible including the inner ring, the outer ring and the balls. The results of this test have been used to study the importance of speed compared to other parameters in increasing the vibration levels of the bearing. In addition, the results of this experiment have been used as inputs to a neural network. This neural network is trained to classify bearing... 

In this research, the main purpose of the controller design is in the second region of operation of a wind turbine, which involves absorbing the maximum energy from the wind. WindPACT 1.5MW turbine has been investigated and the power coefficient of this turbine has been obtained using WT-PERF and FAST softwares. Simulations show that the results of both methods are well matched. Then, using ANFIS, a method for estimating the wind speed is derived from the data obtained by FAST. Inputs to the ANFIS system are the turbine aerodynamic power, rotor speed and blade pitch angle while the output of ANFIS system is the estimated wind speed. The maximum power coefficient of the wind turbine occurs... 

The power control of horizontal axis wind turbines can affect significantly the vibration loads and fatigue life of the tower and the blades. In this thesis, we are going to consider both the power control and vibration load mitigation of the tower fore-aft vibration. For this purpose, at first, we developed a fully coupled model of the NREL 5MW turbine. This model considers the full aeroelastic behavior of the blades and tower and is validated by experiment results, comparing the time history data with the FAST (Fatigue, Aerodynamics, Structures, and Turbulence ) code which is developed by NREL (National Renewable Energy Lab in the United States). In the next, to estimate EWV, a novel... 

In this thesis, with a review on policy simulation and economic reform analysis literature, we design a suitable method to analyze the effects of monetizing energy carriers subsidy on welfare criteria of Iranian households. The selected method is limited general equilibrium that needs demand estimates of goods, services and energy. In firs step,based on 13 years of data on “Iranian Households’ Expenditures and Income” surveys, data are provided as a pseudo-panel. Demand equations are estimated using “Seemingly Unrelated Regressions” for panel data, and elasticities are calculated. In the next step, we evaluated the equivalent variation and equivalent gain measures in each price scenarios.... 

This thesis finds evidence for the presence of adverse selection in the Iranian life insurance market. We use a unique dataset including more than one million policyholders’ profile information alongside their chosen life insurance coverage from the largest Iranian insurance company. Our results not only find evidence in support of adverse selection in this market, but also consider the magnitude of adverse selection relatively notable. Moreover, we found that in addition to the coverage, the other dimensions of contract could be the potential source of adverse selection. Particularly, we focused on the insurance duration and the payment method (monthly, annually, all-in-advance).... 

This thesis aim to the study of the effect of bank’s branching decisions on deposit market. Using panel data banks from Iran, we study effect of branching on market share and market size. In theoretical part, we assume that banks maximize discounted flow of the profits. We also assume that the banks take into account the reaction from rival banks in setting number of branches. Banks are assumed to expect the rival banks react by a lag of one period. In empirical part, in order to distinguish between aggregate market size effect and market share effect, we rewrite quantity of deposit in banks as the product of aggregate deposit and market share. We specify deposit market share function with... 

In the past few years mobile usage is increasing in Iran. Since mobile industry is growing and new innovations are presented, the competition between operators is rising. Although this competition has a great influence on the mobile demand for each operator, lack of the data of the all operators made us to use the data of one of the operators to investigate the demand. Based on the subscriber’s data of Hamrahe-Aval company, it has been introduced an estimation of a demand system for customers of this company by using AIDS model in this essay. This model includes three groups of services: sending short messages, calling to mobile numbers and calling to fixed numbers.
This study has two... 

The identification of the poor and the elimination of their poverty always has been the subject of discussion among researchers and policymakers. Today, most researchers consider poverty as a multidimensional phenomenon, and in addition to income indicator, it has indicators related to the level of knowledge, awareness, well-being and the health of individuals. The study of multidimensional poverty and the search for the discovery of its static and dynamic relationship with income-based poverty is the subject of this research. The analysis shows that both statically and dynamically, there is a substantial mismatch in the identification of the poor households according to these two... 

Since the mid-twentieth century, the issue of gender preference has always been of interest to economists. This preference is demonstrated by sex-selection methods such as differential stopping behavior and sex-selective abortion. While it is almost impossible to look directly into abortion behavior in Iran, due to religious beliefs and illegality, we can investigate gender preference by calculating to what extent parents adapt their fertility behavior to ensure the birth of preferred sex. For this purpose, we use “Households Income and Expenditure Survey of 2019” data from the Statistical Center of Iran. Our results indicate that when Iranian parents are deciding to have second child, they... 

The question of whether sex preferences are present in a certain country has long been of interest for economists and demographers. This study first investigates the existence of these preferences among Iranian parents. Next, if any preference are present, it turns to the task of inferring the quality of the observed preferences. There are two widely used methods for addressing these issues in the literature. The first method is to estimate a Logit model which relates the probability of a mother giving birth to a new child, to the sexes of her previous children. The second one is to estimate a Proportional Hazard model in order to investigate the relationship of the time interval between... 

In standard models, the demand function is considered to be independent from the supply function and the intersection of these curves is considered to determine the price and quantity in the market. The alternative model, called “inducement hypothesis”, describes how the supply side can persuade consumers through particular advices, induce demand for the provided services and though shift the demand curve; i.e. demand is not independent from supply. For the case of physicians, this hypothesis is known as “physician induced demand”. In fact, this theory describes the supply-side moral hazard in the production market. This hypothesis may have vast applications which are different from... 

In Economic literature, investigating effective determinants of driving offences is discussed in Economics of Crime. In this field the effect of economic and sometimes non-economic parameters on offences are investigated. Economics of Crime was introduced as a branch of economics after Becker (1968). Since then different studies have been done and many theories have been made to discuss the relation between economic Variables and crimes in the society. In this study we use a cross-province panel data of driving offences to investigate the Effective Determinants of these offences. The most important result is the deterring effect of the penalty. For example in the regression for the seventeen...