Sharif Digital Repository

This paper decomposes the saving rate into cohort, age and year effects. This objective is accomplished by constructing a pseudo-panel that amalgamates nineteen consecutive, cross-sectional Household Income and Expenditure Surveys from 1991 to 2009. To construct year-of-birth cohorts with consistent composition over time, analyses are limited to those born between 1926 and 1975. Results reveal that those belonging to younger cohorts save a higher fraction of their income relative to their predecessors at the same age. Moreover, the increase in the saving rate can not be explained by the significant decline in household size or rise in educational attainment among younger cohorts. Closer... 

This study estimates a hedonic model for the price of housing in the city of Tehran. Using 1340 observations from the eighth region of the city as a sample and applying geographically weighted regression, the study shows that hedonic price function regardless of space variation in house price, leads to spatial autocorrelation in the error term of the model. Thus geographically weighted regression method can deal with this problem and is able to explain more than 76% of the variation in housing prices. Additionally, almost all three structural (floor area, kind of housing appearance and type of houses), environmental (distance from nearest hospital, park, school, health club and mosque) and... 

In order to measure poverty, researchers used to consider only the income and the financial aspect of poverty; however, further research has revealed that income in itself cannot be a proper and comprehensive index for measuring poverty, and other factors such as education, health, occupation, personal characteristics, cultural activities, political activities, etc. are also significant in determining the poverty index. Based on the information acquired from "household expenditure-income survey", this study tries to take into account all the factors affecting the poverty index, in four dimensions of economic well-being, capability, political participation and cultural participation. Poverty... 

In recent decades, many empirical issues have been accomplished about poverty respect to various dimensions of this phenomenon in micro level. At the start, monetary aspect of poverty was measured in uni-dimensional form but more researches result that poverty may be as a result of education level, health condition and other household characteristics; so multidimensional poverty indices were defined.The study employs the fuzzy-Set theoretic framework to compare levels of deprivation like income, housing, acquisition of durable goods, health condition, social security and education in Iran over time (2004, 2006) using micro data  

Stock exchanges are one of the most important capital markets and let people and institutions to insvest their savings in stocks and therefore earn money. Investors are going to select a portfolio that has the maximum return and minimum risk; so, they try to forecast stock returns and volatilities. Predictability of stock return and volatility is also important for asset pricing and investigating market efficiency. Now, the question is “are stock returns and volatilities predictable using historical returns and volatilities?” In this research, return and volatility predictability of Tehran Stock Exchange indexes by using historical data are investigated. First, the outocorrelation of return... 

Because of the importance of the issue of poverty, in this study, we introduce and copute aspects & dimensions of multidimensional poverty index. The object of this thesis is studing the trend of changes in Iranian households’ welfare during the years 2005 through 2015 and recognizing the economic and social poor households’ characteristics. There are two methods that are used to computing MPI (Multidimensional Poverty Index). One of them is standard method that is given unique weight to each dimension, the other one is questionnaire method which is asked poverty experts to set proper weight to each dimension. Knowing how poverty index (income & mpi) changes, can help policy makers to... 

Fine-grained image classification is image classification where the considered classes are all sub-classes of a certain, more general class. In this setting of the problem, the classes are visually very similar to each other, such that an unskilled human cannot discriminate between them. In this case, proposed methods for the ordinary image classification problem do not obtain good classification accuracy. So proposing new methods for solving this problem is necessary. In this thesis two new methods, based on recent advances in deep learning are proposed for solving the fine-grained image classification problem. First by improving several parts of one of the recent proposed methods for this... 

This investigation is intended to assess the behavior of SCBFs in the presence of typical brace members, which buckles in compression, and BRBs joining by yielding elements. While braces play a role in providing stiffness for structure, central yielding elements will act as energy-absorbing fuses. In this frame type, energy dissipation will mainly be undertaken by BRBs and yielding elements. The mentioned yielding elements do this by initiating plastic hinges in each corner of the central frame. As it is clear, designing a structure that includes the stated lateral-load-resisting system necessitates seismic performance parameters to be evaluated. Hence, by pursuing the FEMA P695 methodology,... 

The seasonal fluctuations in economics variables relate to the different behavior of economic agents across different seasons. In past, seasonality has been viewed as a redundant feature that needs to be removed from data before economic analysis. From 1988, modeling seasonality has become the major concern of many economists; moreover, it was seen that many economic analysis and forecasts could be flawed if seasonality is ignored. In the present research, periodic times series approach is used for the first time in modeling the seasonality feature of the housing market. Regarding the importance of the housing sector in economy from micro and macroeconomic points of view, using a more... 

Time series of asset returns display specific regularities such as bell-shaped distribution, leptokurticity and volatility clustering. Economists have made continuous efforts to develop models that explain these patterns and can be used to predict the return and the risk of holding an asset. These efforts can be classified into 3 eras: Bachelier Era (1900-1960) in which the random walk model was developed for speculative prices. Mandelbrot Era (1960-1980) in which the normality assumption was replaced with the Pareto-Levy family of distributions which are flexible enough to justify leptokurticity and infinite variance. And finally, the Dynamic Volatility era in which the focus was on... 

Methane conversion into higher hydrocarbons has been investigated by non-thermal plasma. The most important advantages of utilizing this type of plasma are atmospheric pressure and ambient temperature of the operating system. In order to prepare non-thermal plasma, a spark discharge reactor has been used with the main prospect of acetylene production. Other components such as hydrogen, ethylene and ethane are also formed in the process as by-products. By optimizing the affecting parameters on methane conversion and products selectivity, maximum methane conversion of 83.2% is obtained. Acetylene yield varies between 25%-63% with input gas flow rate, voltage, frequency and discharge volume.... 

In order to better understand the performance of the Iranian health insurance industry, household decisions to purchase private health insurance are analyzed using a two-stage (Heckman) model on Survey of Family Income and Expenditure data. Probit and OLS regressions are used to examine the factors influencing the probability and amount of private health insurance purchased. Generally, factors affecting the probability of having insurance also influence the amount of insurance coverage purchased. The results show the importance of some demographics on the insurance decision, particularly age, gender and marital status. Socio-economic factors such as education, income, employment sector,... 

The projeⅽt first explores the ⅽonⅽept of operaⅾs anⅾ the basiⅽ ⅾefinitions of the theory suⅽh as the ⅾifferent ⅾefini− tions of operaⅾs ، anⅾ then expⅼores the types of exaⅿpⅼes of topoⅼogiⅽaⅼ operaⅾs anⅾ their properties anⅾ exaⅿines speⅽifiⅽaⅼⅼy the ⅽonstruⅽtion of the Grassⅿann props by us− ing the aⅼgebraiⅽ geoⅿetry tooⅼ anⅾ finally we ⅽoⅿpute the ⅽohoⅿoⅼogy group of Grassⅿann props by using the aⅼgebraiⅽ geoⅿetry tooⅼ anⅾ aⅼgebraiⅽ topology tool  

In this thesis, behavior of multiple pool fires was investigated in the numerical method. Fire modeling is a complex process. The complexity intensify when simultaneous fires occurred, pool fire is the most likely among all kind of fires in city and industrial units. FDS software, a common CFD model for fire simulation, was used to simulate multiple pool fires. Using of CFD models is one of the most advanced techniques to fire simulation and FDS software have been used by engineers and researchers due to using of this technique. In the beginning, review of the existing investigations which FDS performance was examined of fire simulation is presented. Besides of the data gathering, in this... 

This research aimed to investigate the relationship between household poverty and the gender of the head in the Iranian households. The self-reported gender of the head of household (FHH), underestimates the rate of poverty in female- head households (FHH). The self-reported gender of the head of household considers, conventionally, a family as male-head, even if the man of the family is incapable of making money. In much of these families the wife is the sole income holder even though she is not recognized as the head. In this study, a definition for household headship is introduced, which considers head of household the one who provides more than 50% of household income. Using household’s... 

Nowadays evolutionary algorithms help developers to solve many problems in applied science and engineering aspects. So the main goal of this thesis is to apply and verify the ability of evolutionary algorithms and artificial neural networks in optimization of Ethane recovery unit. Algorithms applied in this study are Ant Colony Algorithm, Artificial Immune Systems Algorithm, Incremental Evolutionary Algorithm, Chaotic Based Algorithm, Variable Population Size Genetic Algorithm, Frog Leaping Algorithm, Frog Leaping with Bacterial Optimization Approach and Different types of Particle Swarm Optimization Algorithm. Optimization methods based on local search are also applied in order to compare...