Foreign trade as one of the tools of globalization leads to international competition and participation of countries in economic activities. In the foreign trade process, uncompetitive activities will lost the ability to survive and will increase the level of unemployment. But if foreign trade increases through the development and boom of exports, it will lead to the creation of job opportunities with higher performance. The aim of this research is to analyze the effects of export booms on the unemployment rate in Iran. To this end, the annual data during the period 1974-2012, ARDL model, bounds test cointegration and Granger causality test were used. The results indicate the existence of cointegration between the variables. The results show that the export booms in both the short run and long run have a negative and significant effect on unemployment rate. The error correction term shows in each period 95 percent of disequilibrium will adjust along the long run equilibrium path. The results of conditional Granger causality test show that there is no short-run causality between variables. However, the long-run causality relationship from terms of trade, capital accumulation in tradable sector, capital accumulation in non-tradable sector, labor supply, and inflation to unemployment rate is accepted at the 1% level.

The low rate of economic growth in resource-abundant countries remains as a paradox for economists and socio-political scientists. There have been various explanations for these phenomena. One of the latest explanations considers the under-development of legal institutions as the major factor, which is indicated by non-cooperative and rent seeking behavior of the interest groups, leading to serious economic difficulties. This paper examines the case of oil boom in the context of modern approaches of political economy. The saving rate reaction is explained within the conflicting positions of interest groups in an oil exporting economy. The "Varacity Effect" is introduced and examined, indicating a counter cyclical behavior for the saving rate in a developing economy, where the rise in aggregate consumption may exceed the effects of resource boom. An econometric analysis of oil exporting economies indicates the experience of varacity effect in all OPEC members after the oil boom. In conclusion, it is argued that initiation of certain institutional reforms is crucial for improving the savings behavior and overall performance of resource-based economies.

For the first time, this paper analyzes the portfolio selection theory in the presence of housing market in Iran. One of the important theories about the housing price is household portfolio theory. Based on the theory, housing business cycles have determining effect on housing share in portfolio. For this purpose, a set of assets data consisting stocks, exchange, gold coins, bank deposits, bonds and housing over the period 1991-2006 are used. After calculation of returns, risks and correlation coefficients of assets over the period using Mean - Variance Model and MATLAB software, a combination of household assets in the portfolio have been extracted .The model, through simulating and supposing different weights for each asset determines an optimal combination of assets in portfolio based on risk classification of households: low risk, medium risk and high risk. Then, they are thoroughly examined to explore: whether the presence of housing asset in the portfolio can improve its risk, return and the composition of assets? Efficient frontier which covers all portfolios is also extracted. The results reveal that housing is an important asset in the portfolio during the housing boom period and causes the efficient frontier transmission move outwards.

Housing sector fluctuations have many impacts on economic growth, job creating and households welfare. So, it is very important to determine main reasons of speculative bubbles in housing markets. There is almost general agreement about the role of expectations of buyers and sellers in making of speculative bubbles but, only a few researches try to model it. In this research we try to model speculative bubble in Tehran housing market using agent- based economics. Agents have heterogeneous expectations about long-run fundamentals but change their views because of «social dynamics». Agents meet randomly and those with tighter priors are more likely to convert other agents to their beliefs. Results of modeling show the role of non-fundamentals and heterogeneous expectations in speculative bubbles in the Tehran housing market.

Boom equipped tractor mounted sprayer model TF400, is one of the conventional sprayers in Iran. It is employed in many parts of the country to spray the fields of wheat, barley, potato, corn and many other crops as well as rangelands. Having in mind the importance of environment protection as regards rational use of pesticides along with a consideration of production costs, a study together with an evaluation of this equipment is indispensable to find out the most important parameters effective in its proper operatioJ1. Therefore, in this study, the sprayer undergoes a computerized analysis and simulation to obtain a mathematical model governing the fluid (pesticide) flow as well as the systems components. Towards this end, the equations governing the fluid flow from the diaphragm pump's inlet to fan shape spraying nozzles are initially presented. These non linear differential equations are solved through MATLAB software. Then a computerized simulation of the sprayer dynamic behavior, is presented by use of SIMULINK simulation toolbox. To verify the mathematical model of the system, the sprayer was laboratory tested as follows: Pesticide fluid pressure was measured in two parts of the sprayer in 14 different operating conditions to obtain the real dynamic response of the system. The mathematical model was finally verified considering the fact that there existed a close match between the results obtained from laboratory tests and these obtained from computerized simulation.