فصلنامه مدلسازی اقتصادی
سال هفتم شماره 2 (پیاپی 22، تابستان 1392)

The main objective of this paper is to investigate the survival and risk probability of pegged and floating exchange rate regimes in different countries: those having exchange rate anchor versus those having inflation targeting monetary regimes during 1999-2010. In order to achieve the goal, Duration Model Approach will be used to represent the survival and risk analysis of pegged and floating exchange rate regimes. The empirical findings of this paper suggest that, in two groups of countries, the floating exchange rate is a credible regime and it has a lower risk and then higher survival probability.

During two past decades, many studies have been done by the researchers about the relationship between natural resources and economic growth. Based on the importance of natural resources in economic growth and by considering both its positive and negative effects on the economy, this study tries to review the effects of natural resource abundance on economic growth in Iran and Norway during 1970-2008. The results represent that, in the short-term and long-term, natural resource by itself isn’t an obstacle for economic growth in Iran. Furthermore, economic freedom and human capital in these two countries have significant and meaningful positive effect on economic growth both short and long term.

Wireless Communication Company (WCC) usually faces the problem of in-time phone bill payment by some subscribers and so encountering this group is a very sensitive challenge. In this paper, the researcher tries to analyze this problem through dynamic games by complete information to consider the possible choices of the company, as well as some assumptions about typical subscriber preferences and ranking them. The way of action, existing strategies and their consequences, the sub-game equilibrium, and the total game will be shown in the form of a wide spread game. It is then solved using Sub-game Perfect Equilibrium method (SPE). The game equilibrium reveals that WCC will disconnect the subscriber's phone in one directional form when he or she does not pay the bill and the subscriber quickly reacts via paying the bill and not using the company's services any more.

It is clear that business cycles are inevitable in economy. On the other hand, the economists are always looking for how to form business cycles and so under the effect of economic policies, since the economic situation is depended to these policies. Therefore, the access to more precise business cycles forecasting methods would direct and manage the economic situation and policies powerfully. Hence, the main objective of this study is to construct a new model based on Markov-Switching Autoregressive (MS-AR) model to forecast the business cycles in Iran. In addition, the model constructed is compared to ARIMA to represent its power. GDP data seasonally covers the period 1989: I – 2009: IV collected from Central Bank of Iran. MS-AR and ARIMA models are applied to forecast the behavior of business cycles. By using MAPE, RMSE and Theil criteria (TIC), the results indicate that MS-AR model will work better than ARIMA to forecast GDP business cycles.

In most of empirical studies based on almost ideal demand system (Aids), the elasticity of the price and income estimated by these equations resulted to some sensitive policy making recommendations in microeconomics and macroeconomics. It is in such a case that there is some doubt about reliability of linear estimation of such models. In this study, the performance of linear and non-linear almost ideal demand system is under the investigation. For this purpose, seemingly unrelated regression (SURE) method will be applied to estimate linear model and multilayered feed forward neural network (MFNN) is used to estimate a non-linear one. The results indicate that multilayered feed forward neural network is associated with less error than the linear model, and consequently, leads to a better estimation of almost ideal demand system. This result creates some hesitate on application of Stone price index for linear zing estimation of almost ideal demand system. Therefore, it is suggested that feed forward neural network will be applied to estimate almost ideal demand systems.

In this paper, the effect of subsidy on the long run urban water demand function has been examined in the city of Qom. To do this, the researchers have used monthly time series data during 2008:01-2011:06. The model estimated is based on the maximization of Stone - Gery utility function, autoregressive and co-integrated model approaches. The results indicate that the decrease or removal of water subsidy would decrease urban water demand. Also, Qom urban water demand has a negative relation to the price of water and other commodities and has a positive one to the revenue. All of these relationships are completely in line with economic theories. The province urban water demand is inelastic to water and other commodities prices and so a necessity for revenue. Also, the minimum level of water consumption of the households, when removing the price subsidy, is 38 liters per day.

Current study aims to investigate the effect of incentive programs on trade and export model of agricultural products. To do this, agricultural products will be divided into 3 categories by various ratios of export awards. Then, the influence of export awards on the product export model will be analyzed 5 years before and 8 years after implementing export award policy during 1997- 2000. To investigate the effect of awards provided on the trade model, 24 agricultural products are divided 3 groups. The first group includes products in which no award is provided. The second group received 1.5 percent or less subsides and the last one received more than 1.5 percent of subsides. Multi-variance analysis reveals that there is no significant difference between the first and second groups (no award and less than 1.5 percent of awards). However, there is a significant difference between the third (more than 1.5 percent award), the first and the second ones. In the other words, to make effective the export awards and incentives, higher than cut-off level awards are required.