Journal of Economic Modeling Research

  The intensive effects of “targeted subsidies plan” and its implementation and that of the price of energy carriers on macroeconomic variables such as private consumption and Gross National Product, therefore increase in the price of energy carriers and the relevant issues have been debating and discussing for a long time. Regarding the significance of the issue and also its effect on the economic and society welfare, further and more comprehensive investigations into this subject seems to be necessary. This paper is presented with a review of previous studies and then explores the effect of the increase in the price of energy carriers on the three important macroeconomic variables, i.e. GDP growth, inflation and private consumption in the context of a structural vector regression to model SVAR. The results show that due to implementation of this plan, the economic growth and the private consumption decrease but the inflation will increase. The results showed that, the energy price index shocks the most influence on inflation variation are explained so that voters, in the medium term and long-term changes and about 40 percent of fluctuations in inflation, energy price shocks is described. Other findings of this study is that, in the long-term energy price shocks indices respectively about 20 and 11 percent of the fluctuations in private consumption and gross domestic product by the explained. It should be noted that all results, without considering the effects of resource redistribution payment received from government subsidies are.

  Public-Private Partnerships (PPP) models using the capacities of private sector have provided a background to supply public services and infrastructures in different ways. Transportation sector as a fundamental sector of economic development in Iran needs public-private participation models. For this purpose a theoretical literature of public-private partnerships has been reviewed and then the barriers to the development of such partnerships in transportation sector of Iran economic, infrastructure, legal and social areas were investigated. Finally with AHP, TOPSIS and SAW methods of Multi Criteria Decision Making (MCDM)the barriers were prioritized and their relative importance was analyzed. The results of three methods indicate that factor of financial markets limitations and availability of financing is the main barrier to the development of public-private partnerships. Although there is a little different among the results of TOPSIS in rating some final factors compared to other two methods, by calculating rank correlation coefficient (Spearman) the null hypothesis(the lack of correlation between the results) was rejected and with 99.75 percent probability all of the result are similar. Ranking results of barriers to the development of public-private partner ships in this study can be taken into consideration in policymaking and determining the requirement to use these models in the fields of transportation and other infrastructural areas.

  In recent years, financial economists have increasingly recognized the interaction between market structure and capital structure or financial decisions of the firms.

  This research analyzes the relationship between market structure (power) and the capital structure (leverage ratio) of listed companies in Tehran Stock Exchange (TSE) based on static and dynamic approach. In this research we study a balanced panel dataset of 101 firm-year observations from 2006 to2010 and test significant relationship for testing hypothesis.

  First we use pooled regression to determinant the relationship between capital structure, market structure (Tobin's Q) and five control variables including profitability, size, collateral value of assets, growth rate of assets and uniqueness of assets. After employing chow and hausman test, we selected fixed effect panel data model. Also we employed GMM method to have more efficient result and also to cope with the unobservable firm-specific characteristics and endogeneity problems.

  Our results suggest that the relationship between leverage and market structure is non-linear (cubic) due to the complex interaction of market conditions, agency problems and bankruptcy costs. The study finds a negative relationship between capital structure and profitability and also positive relation between capital structure and the size. So, profitable companies tend to use internal financing such as retained earnings and issuing new shares instead of debt financing. Also big companies prefer to use more leverage due to desirable conditions for getting loans. Our evidence shows that Iranian listed companies are generally more subject to agency cost theory (limited liability effect) and tax shield theory. Finally, the system-GMM results reveal that managers of Iranian firms tend to adjust dynamically their leverage ratios over time.

  Storing the electrical energy in large scale is impossible. So, it is necessary to identify the factors affecting the electricity demand. Researchers have used different methods to forecast the future demand of electricity, among them intelligent methods and fuzzy based methods are more popular. Since ANFIS structure is based on researcher’s experience about phenomenon, the created structure may not have the best result. Therefore, we used PSO-ANFIS structure.

  In this paper long term electricity demand is forecasted until the year 2025 by hybrid PSO-ANFIS algorithm. The results confirm the high power of the Adaptive Neural based Fuzzy Inference System in forecasting the electricity demand. Results also indicate that the forecasted electricity demand will be 401 billion KWh in 2025. The prediction performance of the proposed technique is more accurate than the ARIMA model.

In many Developing Countries liberalization of international trade has been accompanied by demand for skilled labour and inequalityof wages.Thisphenomenon seems to be inconsistant with the Stopler- Samuelson Theorem.Studies in this respect show that imported high –tech capital andintermediate goods are skill-based, thus increasing the relative demand for skilled labour.
In such circumstances, identifying the impact of such goods upon the demand for skilled labour in Iran is of great importance.
In this paper, by using Translog cost function and the Method of Seemingly Unrelated Regression, short and long run demand function for the period of 1977- 2014 in Iran has been estimated. Althoug the short and long –run results arecompatible with the theortical expections, the investment on domestic research and development regarding the employment of skilled labour has been effective only in the long-run and not the short –run.

Fiscal decentralization that is considered a transfer of responsibilities that associated with accountability to sub – national governments, increases efficiency and providing better access to public goods in the Economy. According to the five-year development plans of Iran creating and allocating structure for provincial budgeting, fiscal decentralization generally is moving in the costs of its Provinces in order to give more responsibility to the provincial development projects. The aim of this study is an investigation of effect for partial fiscal decentralization on regional economic growth of Iran. Fiscal decentralization index is proportion of provincial's capital assets to government's capital assets, So this researches the effects of decentralization on economic growth in the framework of Solow's growth model. That the results based on data from 30 provinces between 2000 and 2007 on the panel data estimation, shows partial fiscal decentralization which has a non-linear relationship with the growth (convex shape) and partial fiscal decentralization Indicts the Optimal degree in growth of regional economy in Iran.

As one of the important energy forms, natural gas consumption has an upward trend in recent years. Therefore management and planning for provision of it requires prediction of the future consumption. But many of prediction procedures are inherently stochastic therefore it is important to have better knowledge about the robustness of prediction procedures. This paper compares robustness of two prediction procedures Artificial Neural Networks as a nonlinear and ARIMA as a linear model. using resampling method to predict the monthly consumption of natural gas in the household sector. Data spans from 2001-4 to 2012-3, to train the networks, we used genetic algorithms and Particle Swarming Optimization then results were compared using 10-fold method. According to the results, the particle swarm optimization (PSO) outperforms the genetic algorithm. Then we used data from 2001-4 to 2010-3, with resampling by 2000 to predict the  natural gas consumption for the 2001 -4 to 2012-3 and to form critical values. Results show that prediction by a mixed method using ANN and PSO is more robust than ARIMA method.

The main purpose of this study, is to evaluate the effect of diversion earnings forecast and earnings realized on returns stocks in Tehran Stock Exchange. In fact, this research aims to examine the diversion of earnings resulting from the diversion of corporates managers forecasts earnings, what impact these diversion of earnings have on the returns of stock price. To achieve this, 194 companies listed in the Tehran Stock Exchange selected in the period of 2005-2013.
In this study, two groups of companies experienced the highest returns and lowest returns over the period studied, have been selected. Multi-factor model of Fama and French (1993) was used as the theoretical basis. The results indicate that forecasts of companies have experienced highest returns in comparison with lowest returns are more cautious and accurate than prediction of their future earnings. Changes in earnings realized and Tehran Stock Exchange index returns have positive and considerable relationship with stock returns as well, but these relationships for companies with highest returns are stronger than companies with lowest returns.

Today one of the basic conditions for economic development in one country, is the high performance of energy sources used in different sections of the country economy. When the efficiency is raised, one of essential requirements is benefit from technologies and equipments with higher technical and performance specifications, and removing economic barriers or improving economic policies, in order to achieve as higher efficiency as possible in energy consumption. Considering that close to half of the our country energy consumption accounted for households and this sector is the largest consumer of energy in the country, and considering the importance of the issue of energy consumption, in this study we decided to analyze and scrutiny the phenomenon of energy efficiency in the household sector, and to achieve accurate and scientific analysis in this area based on expert opinion data, using structural equations modeling technique in LISREL. Based on the result of the model, economic policies (price and none price) has relatively more importance than the technical and technological solutions to the problem of improving energy efficiency in the household sector, as well as important and effective indices of each of these factors are extracted and identified. According to it, "levy a tax on energy consumption" among economic policies, and indicators of "e-government infrastructure development", "development of smart counters and Equipments WARNING energy consumption in homes" and "development of vernacular architecture patterns adapted to climatic conditions in different regions of the country" in connection with Technical foctors, have the greatest impact on energy efficiency in the mentioned sector. However, if the relationship identified for both the economic policies and technical-technological factors with the dependent variable "performance" was not acceptable very good, this matter can indicate this fact that there are other variables and factors that are influencing and can have a great role to play. Among these factors it can be addressed the socio-cultural factors and insights and norms of society which can be a help to aggravate the problem of inefficiency in energy use.