فصلنامه تحقیقات مدلسازی اقتصادی
سال ششم شماره 23 (بهار 1395)

Regarding to studies in different countries the research and development (R&D) play a major role in economy growth. Investment in R&D increase level of knowledge, and we have increase in production efficiency by knowledge increasing, after that economic growth will improve by productivity channel. Many studies exist on the R&D but in any of them not used the same variable for this indicator. The time series of knowledge level is not visible because of complexity the calculations and measurements of this variable. In this study the level of knowledge is intended as an unobservable variable. After that using LP and OP method the time series of this variable is extracted during the period 1974-2014 for Iranian economy. Estimates this series will be an important way for future empirical studies in research and development. Algorithms and methods that used in this paper can be run for other countries. Based on LP method, results shows during the 40 years of knowledge for Iranian economy has upward trend and the averages of grow rate of knowledge level is 0.42 percent for each year.

Value at risk (VaR) is one of the most important risk measures for computing risk which is entered in financial framework in past two decades. In general there are three approaches including parametric, nonparametric and semi-parametric is used for estimating of VaR. this paper present a new method that is named window simulation which is classified in nonparametric approach. Processing of VaR calculation in window simulation method based on reproduction of data such as Monte Carlo simulation. But, in this new method, data production is done in basis of distance and similarity measures. Considering generated distribution quantile, VaR is estimated. Next, VaR of Tehran Stock Exchange indices are computed by this method. Also the accuracy of estimated VaR is evaluated by backtesting statistics. Empirical results indicate that based on window method, the best outcome is associated to measures of Euclidean, DTW, Kolmogorov-Smirnov, square χ^2 , distance-similar and cosine respectively.

The electricity industry that has been administrated with integrated vertical structure worldwide is now undergoing dramatic changes. Electricity industry is converting to a competitive industry in which market powers determine the price of electricity, there for it is important to identify market power. The Electricity Market of Iran and Iran Grid Management Company were established in 2003 and 2004, respectively. One of the most important objectives of the restructuring of Iran’s Electricity Market is to establish a competitive environment. The purpose of this study was to assess the level of competition among regional power companies in the electricity market in 2013. The method employed separates the strategic companies from marginal companies by market share index in the hours of peak consumption in summer, and then simulates the performance of the strategic companies using Cournot’s model. Each Cournot (strategic) company aims to maximize its profits, assuming its competitors keep a constant production. This goes on to reach equilibrium, as long as companies do not take advantage of changes in their production. The results of the simulation shows that firms with higher market share at the summer peak hours have been acting strategically in 2013. Another part of the study investigated the circumstances of the power plants of these companies. Lerner’s index was estimated and showed that all the power plants of Tehran’s Regional Electricity Company had an index of higher than 50 percent which is an indicator of their high market power.

This paper investigates the relationship between monetary policy and stock market fluctuations for Iranian economy within a DSGE model. This study models the role of monetary policy in two monetary regimes including money growth and Taylor rule with traditional factors and optimal simple rule in the new Keynesian monetary framework with nominal wage and price rigidities in the Iranian economy. Bubbles in our model emerge through a positive feedback loop mechanism supported by self-fulfilling beliefs. Results show that: first, using an optimal simple rule and determining the optimal coefficients of the Taylor rule by policy makers decrease the loss function. Second, the sentiment shock which represents the size of current bubbles relative to newly born bubbles and transfers to the real economy through endogenous credit constraint, drives the movements of stock market fluctuations and variations in real economy, leading to explain the positive contemporaneous correlation between stock prices and the real economy Third, using an optimal simple rule and determining the optimal coefficients of the Taylor rule with stock price Fluctuations by policy makers decrease the loss function and it confirms that monetary policy should respond to stock market bubbles in the economy

Targeted subsidies plan affects income distribution and poverty through several channels. On most of the analyzies, changes on labor supply are not considered. Increasing nominal income alone after paying cash subsidy rule can reduce labor supply in targeted subsidies. This issue may decrease effect of targeted subsidies. In this research by CGE we calculate the result of impact of energy price increase and direct cash subsidy transfer with considering labor supply decrease in the first phase of this plan. Then we use this CGE data to calculate the poverty index and income distribution. The model is calibrated based on 2001 Micro Consistent Matrix (MCM) designed by Research Institute of Planning and Management Deputy Strategic Planning and Control. The results of the model show that while the plan reduce supply of labor, it improve income distribution and poverty in Iran. The results also reveal that the percentage of improvement in purchasing power of rural deciles is more than the percentage of improvement in purchasing power of urban deciles.

Environmental quality is affected by many factors such as economic and political inequality. The main purpose of this article is to investigate the effects of income and political inequality on the environment quality in the selected countries. Using the Generalized Method of Moments (GMM), the effects of gini coefficient, democracy index and income per capita, energy consumption and human development index on environmental quality are estimated for 57 countries during the period 2000 to 2012. The results show that income inequality and Political inequality significantly had a negative effect on environment quality. While the energy consumption has the negative effect on the quality of environment, improvement in human development index and the income per capita have a positive effect on the quality of environment. This finding might has important policy implication for policymakers and authorities to achieve sustainable development in different countries.

Modeling price fluctuations in financial markets is very important. We try to model price fluctuations in Tehran stock exchange using heterogeneous agents’ model. We used agent-based computational approach. In this model, there are two kinds of agents, some agents have extrapolating expectations (chartists) and others have stabilizing or mean-reverting expectations (fundamentalists). The dynamics of shares of these two types of agents make price fluctuations. For determining the relative effectiveness of agents expectations, Diechi and Westerhoff (2012) method, is used. For this purpose, weekly data of Tehran Stock Exchange price index (TEPIX) from 1997 to 2014 were used. Modeling results show that the relative sensitivity of buyers with different expectations, and their relative impact to aggregate demand, have significant and important role in the price dynamics of Tehran stock market. We also show that the relative impact of chartists to price fluctuations very important and over the past two decades, the share of them from aggregate demand have been more than 80 percent.