Sharif Digital Repository

Vibration is one of the most important factors in design, operation and lifetime of drill strings. There for, investigation of vibrations in drill string, like every other rotary machine, is very important. The main goal of this research is developing a nonlinear model for a drill string system dynamics in an inclined well. Effects of drilling mud flow rate, weight on bit, angular velocity along with viscous damping, on the stability and vibration of a drill string are studied. Dynamic equation of the model is developed considering axial displacement and lateral bending geometric nonlinear coupling. The effect of drilling mud flow is modeled using Paidoussis formulations. Equation of motion... 

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... 

This thesis aims to the study of quality-quantity trade off in the family through investigating the effects of family size and birth order on their educational attainment. The latter has been chosen as a criteria for measuring the quality; to measure the effects of quantity we have used the twins for the instrumental variable as an endogenous shock in the family size to reduce bias that happens as a result of omitted variables bias and to measure the effect of family size on it’s quality more accurately. We have also used censored regression to eliminate the bias of student children in the sample.In addition to concentrating on the differences between children of different family sizes we... 

In the past few decades a range of human capital theories were developed by economists. In all these, education and training are considered as a prominent aspect of the human capital. Among all influential factors on the education, the role of the family in the allocation of educational expenditure is one of the most important factors. In this research, we investigate whether in gendr discrimination among sibiling is observed in Iranian households. Based on household budget data, we estimate the Engel curve in order to investigate the gender discrimination in the allocation of educational expenditure. Families divided into 6 clusters based on the composition of their children and the tests... 

Auction literature and economic theories advocate common valuation among bidders in mineral rights auctions. In this study, we have tried to examine the assumption of common valuation between bidders in a first price sealed bid auction. It examines the common valuation hypothesis by assuming the information symmetry and the exogenous entry of bidders. The findings of this study suggest that bidders’ valuation in a first price sealed bid auction of natural resources may be private or common value. We use the non-parametric estimation model to find that after the federal government imposed Area-wide Leasing in the Gulf of Mexico, bidders’ valuations changed from private valuation to common...