Showing 14 results for mohammadi
Dr. Vahid Mahmoudi, Dr. Shapour Mohammadi, Dr. Hasti Chitsazan,
Volume 1, Issue 1 (10-2010)
Abstract
The characterization of memory effects in crude oil markets is an interesting issue that has attracted the attention of researchers from different disciplines, from econophysics to more classical economics. The importance of the problem relies in the fact that the departure from uncorrelated behavior would imply the presence of not-random effects which, in principle, can be exploited for arbitrage.
This paper tries to contribute into the issue by estimating the memory effects by means of different parametric, semi-parametric, and non-parametric methods. In the other words, this paper provides analysis on the memory of the oil markets measured via the fractional integration parameter (d) by estimating it with various methods such as the MLE, NLS, GPH, Whittle, Lo, Hurst Exponent and Wavelet. To achieve this goal, we use the daily time series for WTI and Brent spot crude oil prices as well as 3-month futures, and further divide them into yearly subsections to obtain the historical series of memories.
Results of the whittle and wavelet estimations, which are better suitted for this analysis, show no evidence of a long memory process. However, the oil price time series exhibits a nonstationary mean-reverting behaviour.
Note that in this paper the behaviour of memory is our concern instead of the memory value itself. The results of memory changes trend shows that memory of international oil markets does not have an important trend change. In the other words, in our study period the efficiency of the market does not have an important decline or increase.
Dr Rahman Khoshakhlagh, Dr Rahim Dalali Isfahani, Nasser Yarmohammadian,
Volume 2, Issue 6 (12-2011)
Abstract
Environmental Kuznets Curve ( EKC) theory has evolved over several decades from its initial intuitive conception to the complex theoretical models of today. Through successive steps of empirical and theoretical debate, a quadratic relationship between income and environmental degradation has been proposed, criticized, defended, and criticized again.
Along the way, each finding have new look at the subject. Critic that is provided by Mazzanti et al. (2007) and Stern (1998) is that instead of attempting to gain insight into the underlying mechanics of an EKC theoretical foundation, there are undue focus on exploring empirical regularities among a large set of variables. These critics from opponent and supporter cause researcher to review their approach and take more concerns on details and methodology of EKC theory that make the way of theoretical works.
In this paper, a microeconomics model is provided in which household confront with decision about consumption of dirty and clean goods. It is showed that household make decision in the way that, as income increases, environment pollution rise at first and then fall when household substitute dirty goods by clean goods.
Homa Ghasemi, Dr Mostafa Dinmohammadi, Dr Esmaeil Najafi,
Volume 2, Issue 6 (12-2011)
Abstract
Data envelopment analysis (DEA) estimates the relative performance of decision making units (DMUs). This paper uses the idea of the Analytical hierarchy process (AHP) method and fuzzy set theory to modify the model of DEA which can be used to evaluate the performance of business units. In this paper, a new method has been proposed for estimating the performance of DMUs with interval data and weights of data. The models proposed in previous studies have interval data or interval weights of data, so the proposed model has more flexibility than previous studies . Thus, innovation has been done theoretically and the experimental part is for testing the theory. Finally, a method is introduced for ranking the DMUs by computed performance. In order to prove the applicability of the proposed method, a case study for ranking of some Iranian automotive companies products is given. The model results indicate that the proposed model will be useful for practical problems, especially when the number of choices is limited.
Mehran Amirmoeini, Teymour Mohammadi, Morteza Khorsandi,
Volume 5, Issue 18 (12-2014)
Abstract
This paper tries to model the electricity demand in Iran’s industrial sector which captures economic factors and also non-economic exogenous factors. The structural time series model (STSM) approach is employed which allows using economic theory and time series flexibility. In this approach the role of UEDT (Underlying Energy Demand Trend) including technological improvement and structural changes is modeled, therefore the income and price elasticity are estimated more accurately. The results show that the UEDT has the stochastic nature. And UEDT has a great impact on industrial energy demand during 1975-2012. So, the electricity has not been used efficiently in this sector. In the short run the estimation of the income and price elasticity are 0.42 and 0.11 respectively. The value of the cross-price elasticity of electricity demand is estimated about 0.06. It shows that natural gas substitute electricity in industrial sector, however it is small.
Bagher Adabi Firouzjaee, Mohsen Mehrara, Shapour Mohammadi,
Volume 7, Issue 23 (3-2016)
Abstract
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.
Dr Mohammad Mahdi Barghi Oskooee, Ahad Mohammadi Bilankohi,
Volume 7, Issue 25 (10-2016)
Abstract
Energy as one of the most important factors of production, as well as one of the most important marginal products, has effential role in trade and economic development.The importance of energy has increased after the two oil crises in 1970’s. The relationship between energy and trade is an important topic to study for several reasons. If energy consumption is found to Granger cause exports or imports, then any reductions in energy consumption, coming from say energy conservation polices, will reduce exports or imports and lessen the benefits of trade. Energy conservation policies which reduce energy consumption will offset trade liberalization policies designed to promote economic growth. This places energy conservation policies at odds with trade liberalization policies.In this regard, the impact of trade on energy consumption through energy applications in the production process of import and export goods and their transportation is included. This study uses panel data to investigat effect of trade on energy consumption in D8 countries (Bangladesh, Egypt, Indonesia, Iran, Malaysia, Nigeria, Pakistan and Turkey) during the years 1990 to 2014. The results indicat that foreign trade has a significant and positive impact on energy consumption. The findings show a significant and negative impact of energy prices on energy use.
Ezatollah Abbasian, Mohammad Jafari, Ebrahim Nasiroleslami, Farzaneh Farzaneh Mohammadi,
Volume 8, Issue 28 (7-2017)
Abstract
In recent years, with increasing of international sanctions and oil revenues falling in Iran, more attention has paid to public spending and taxes as a source of government financing. In this regard, numerous studies have focused on the issue of taxation and its role in economic development. However, the most studies in Iran analyses the role of taxes on macroeconomic variables such as economic growth, inflation and income inequality, and there is no research in the row of the changes in tax income over the business cycle. In this study, using the dynamic least squares method, short and long-run elasticity of tax bases in Iran in response to changes in GDP over the period 1973-2014 is calculated. The results shows that in the long run, the elasticity of income and corporate tax are statistically greater than one and for other tax bases are not significantly different from the unit. In the short run, elasticity of corporate tax is different from unit and other tax bases were not significantly different than unity. According to these results, it is suggested that the Iranian government should have less focusing on income and corporate tax during the recession period
Hosein Mohammadi, Mehdi Mahmoudi,
Volume 8, Issue 28 (7-2017)
Abstract
Interest rate is one of the most important policy variabels in macroeconomic. Global financial crises and big debt in some countries around the world, make the importance interest rate more explicitly. In the carrent study, the effect of interest rate, inflation, government investment and expenditure on GDP capita per was investigated using panel data approach. Forthermore panel VAR method was used to consider the effects of each mentioned variables on each other and investigating causality relationships between these variabls. 20 Islamic and 19 Non-Islamic countries during 1990-2014 were selected for this study. The results show that in both Islamic and Non-Islamic countries, interest and inflation rate have a significant negative effect on GDP per capita. Government investment in both groups of countries have a significant positive effect on GDP per capita. These results are inline with economic theories. Finally, government expenditures in these groups of countries have different effect on GDP per capita. also lowering interest rate Non-Islamic countries has a considerable effect on other variables.
Hosein Mohammadi, Morteza Mohammadi, Mohammad Tirgari-Seraji,
Volume 8, Issue 30 (12-2017)
Abstract
Proposed by the World Bank, in which the emphasis is on the participation of all sectors in order to achieve comprehensive development in economic, political, social and cultural fields. In this research, by using data of governance quality in 97 countries in 2000-2012, using panel data method, the effect of governance quality index and its sub-indices on the growth rate of per capita GDP is studied. To achieve the comparable results, countries have divided into five groups with low income (first group), with lower than average income (second group), with higher than average income (third group), high income and non-OECD (Group 4) and high-income and OECD (Group 5) countries. Then the effects of some explanatory variables such as governance indicator and its sub-indices on the per capita GDP is estimated for each group of countries separately. The results of the research indicate that in the studied period and for the countries under study, the governance indicator and its sub-indices do not have the same effects on GDP per capita in different groups of countries. Voice and accountability index has a positive significant effect on per capita GDP growth only in three groups of countries (third, fourth and fifth groups). Political stability index only has a positive significant effect on per capita GDP growth in the third group. The government efficiency indicator only has a positive significant effect on per capita GDP growth in the third, fourth and fifth groups. In the first group, only the regulatory quality index has a positive significant effect on per capita GDP growth. This difference in the way indicators are used implies a difference in regulatory policies in order to influence the per capita GDP growth in different groups of countries.
Ali Takroosta, Parisa Mohajeri, Taymour Mohammadi, Abbas Shakeri , Abdoulrasoul Ghasemi ,
Volume 10, Issue 37 (10-2019)
Abstract
Oil price wild fluctuations impact the economies of developing countries as well as those of developed ones. Focusing on OPEC’s political risks as a proxy of precautionary demand, this study aims to disentangle oil price factors using an SVAR approach for 1994Q1 to 2016Q4. We disentangled oil price shocks into political risks, supplies, global demand for industrial goods and other oil price shocks. Our results highlight that shocks originated from different sources affect oil prices differently in terms of both their lifetime and directions. Besides, it is revealed that the structure of oil market has changed due to the 2008 financial crisis, increased oil price fluctuations, changes in OPEC’s behaviour and accordingly its market power, and the advent of new shale oil technologies, thus affecting oil price sensitivities. Therefore, we found out that OPEC’s political risks affected oil markets way more significantly in 2008-2016.
Pegah Pasha Wanous, Javid Vahrami, Hossein Tavakkolian, Taymour Mohammadi,
Volume 11, Issue 39 (3-2020)
Abstract
The effects of International financial integration on the fluctuations of variables in response to shocks are a matter of heavily concentrated literature of the business cycle in recent years. In this paper, a New Keynesian DSGE model is developed in which there is a channel for capital account changes through the foreign deposit's inflow and outflow. Then the effects of financial integration are simulated. The integration factor is defined by the percentage of the total foreign deposits absorbed by the banking system. This coefficient could change due to changes in effective domestic interest rate and global interest rate. This paper shows in presence of oil shocks, the fluctuation of production, consumption, real exchange rate and variables of the banking system such as deposits and loans, is higher in financial integration but there is no significant difference in inflation. In presence of technology shocks, there is no significant difference.
Abolghasem Golkhandan, Sahebe Mohammadian Mansour,
Volume 12, Issue 46 (12-2021)
Abstract
Based on theoretical foundations and empirical studies in the field of the relationship between natural resources and internal conflict, 4 states can be imagined: a. Positive relationship between natural resources abundance and internal conflict (hypothesis of political resources curse) b. positive relationship between natural resources scarcity and internal conflict (hypothesis of political resources endowment) c. Non-linear relationship between natural resources and internal conflict (combination of state A and B) d. Absence of relationship. Based on this, the main purpose of this article is to investigate the relationship between natural resources types and internal conflict risk in the MENAP region countries during the period of 2000-2019 using the System Generalized Method of Moments (SGMM). For this purpose, the index of the percentage share of total natural resource rent from GDP and eight separate indicators including: the percentage share of oil, natural gas, coal, forest and mining rent from GDP, the percentage share of fuel export and the export of ore and metals from the export of goods and the percentage share of arable land in the total area have been used. The results show that there is a U-shaped relationship between the total rent of natural resources and the internal conflict risk; In other words, countries with a shortage of natural resources as well as countries with an abundance of natural resources have a higher internal conflict risk than other countries. This U-shaped relationship is also confirmed for oil rent and fuel export. Also, coal and forest rent have a meaningless effect and arable land has an inverted U effect on the internal conflict risk in the studied countries. The evaluation of the marginal effect of the total rent of natural resources on the internal conflict risk shows that its value varies from -0.08 to 0.1. According to the other results, per capita income and democracy have a negative and significant effect, and population and religious and racial tensions have a positive and significant effect on the internal conflict risk.
Mr Abdolah Afshari, Mr Teimour Mohammadi, Mr Farhad Ghaffari,
Volume 13, Issue 50 (3-2023)
Abstract
This research investigated the effects of oil revenue decreases as a non-linear model based on Threshold Vector auto-regression(TVAR), with an emphasis on Iran’s sanctions during the period of 2003–2021 with seasonal data. Real oil revenue growth was selected as a threshold variable; during the two regimes, the threshold was selected as -0. 021 for oil revenues, and by the generalized impulse response functions(GIRF), the effects of oil revenue increases on economic growth were investigated. Results revealed that shocks of oil revenue in upward and downward regimes had different effects on economic growth rates. The effects of shocks of oil revenue on economic growth in a downward regime were positive until the second period, and after that, they decreased, and after the sixth period, the economic growth was negative. And in the upward regime, it was positive, and after the first period, it decreased at a lower rate than in the downward regime and finally tended to zero. Finally, it can be concluded that the effects of oil revenue decreases on economic growth rate were more in the downward regime than upward, revealing that sanctions and decreases of oil revenue have a great impact on reductions of production and economic growth. Therefore, it is recommended that the government, by implementing true politics and economic programs in line with the reduction of sanctions, reduce the sanctions' effects on production and economic growth.
Alireza Moradi, Mehdi Mohammadi,
Volume 14, Issue 52 (9-2023)
Abstract
The main goal of this research is the impact of the wage gap between managers and workers on stock returns: the mediating role of investors' supervision. In terms of categorizing the research according to the method of data collection, the current research is of the causal and post-event type. The research method is correlation. In this research, library methods were used to collect information. Library methods have been used to collect information on the theoretical foundations and literature of the topic, library resources, articles and required books have been used, and Kodal website and Rahavard Novin software have also been used to obtain statistical information. In this chapter, using data collected from a statistical sample of 76 companies admitted to the Tehran Stock Exchange in the period of 2015-2022. Hypotheses were tested using Pearson's correlation test and Limer's F test in the Eviews13 software environment. The results of the regression test showed that the wage gap between managers and workers with the mediating role of investors' supervision has a significant effect on stock returns.
