فصلنامه تحقیقات مدلسازی اقتصادی
سال هشتم شماره 30 (زمستان 1396)

Construction projects are the basic requirements of sustainable development and growth. Inefficient procedures of implementing the construction projects, regardless of our financial and administrative capacities, has imposed a large amount of unfinished and occasionally stopped projects to national economy. Since there are various components that affect the fate of projects, therefore, the main purpose of this paper is to answer this question that whether the political cycles affect the adoption and implementation of provincial construction projects or not? In order to answer this question, two hypotheses are considered in this paper. Therefore, GMM dynamic method was used to estimate the model and test hypothesis in the years 1997-2014. Hypothesis one: political cycles affect the fate of construction projects, and the second hypothesis: the impact of political cycles on the adoption and implementation of construction projects are larger in the year prior to political cycle (election). Therefore, in order to estimate the model and test the research hypothesis, provincial data during the years was used. Results of testing two hypotheses suggest that parliamentary and presidential political cycles have a significant positive correlation with the construction projects. Results also show that the presidential political cycle has a larger impact on construction projects, meaning that the impact of political cycles on the process of adopting and implementing the construction projects in the year prior to the political cycle is larger. In this regard, in order to eliminate the impacts of the governmental and parliamentary political cycle on construction projects, it is recommended to determine a competent authority that has the necessary qualifications as well as the sufficient degree of independence and supervision power over the project's Feasibility studies. The referenced mentioned will be approve projects based on objective justification-technical and district-based studies and it prevents the adoption of development plans based on the political considerations of the government and parliamentarians.

Due to the more dependence among countries and the raised demand for energy, the energy trade have increased during recent decades, while its major share is intra-industry trade (IIT). In this regard, countries are trying to exploit the diversity of a particular product, as well as the technology transfer and knowledge of technology which generated by IIT in this sector. According to the importance of role of IIT in the economies, this study will identify the determinants of IIT in the energy sector among Iran and its major trading partners using gravity model and Poisson pseudo-maximum-likelihood (PPML) method during 1997-2016. Based on the results, the effects of gross domestic product (GDP) per capita of Iran and the selected countries, the products’ diversification in the energy sector of Iran and its partners, access to the open sea for Iran's trading partners, and foreign direct investment (FDI) in the energy sector in Iran are significant and positive on IIT. However, the geographical distance, transportation costs, and trade imbalances among Iran and the selected countries have had the significant and negative effects on IIT.

One of the causes of unemployment is lack of fit between individual skill and needs for skills in the community. The situation of mismatch between the demand and supply of labour, particularly in terms of skills is defined as structural unemployment. Therefore, in this study quantitatively explores the impact of skill mismatches one of the main parameters of structural unemployment on unemployment rate. For this purpose of information available in the Labour Force Survey from 2006 to 2013 is used. Skill mismatch index is calculated from the root mean square error in supply and demand for skills. According to results of this study, skill mismatch have a significantly and positively effects on the unemployment rate. So thata1%increase in skill mismatch index led to an increase in the unemployment rate will be 0.13%. Therefore, creating exact information about job vacancies , reforming the contexts of courses and creating new fields in new areas according to necessities of entrepreneurs in order to updating of applicants knowledge should be mentioned.

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.

Forecasting tax revenues is vitally important issue for optimal allocation of taxable resources, planning and budgeting in national and regional levels and knowing the potential national participation in public expenditures. The classical optimization based on mathematical methods may not be reliable in real world and mostly inefficient and inapplicable in complicated world due to their restricted assumptions. The smart optimization may help us to find the solution. This essay based on modified PSO methodology .The initial trial based on the data during 1971- 2007 in case of various direct and indirect taxes , and using updated data during 2008- 2012 for final forecasting , to estimate tax revenues for upcoming next three years (2013 up to 2016) by MATLAB software.

In this study, we estimate the demand for natural gas in the subsection manufacture of basic metals of Iran using structural time series model (STSM) over the period of time 1981-2013. Such model contains unobservable elements which have been transported to state space model with the use of kalman filter and is estimated by implementing maximum likelihood approach. Also, because the Targeting of Subsidies Plan was approved by the Iranian parliament at the end of 2010, so we evaluate the role of this plan on energy demand of industrial subsectors. Finding of the research is that, first of all the nature of the trend is smooth one. Secondly, it is changing on a nonlinear basis. The estimated demand function shows that price elasticity for natural gas in the long and short run, correspondingly, are (-0.30) and (-0.79) and production elasticities of natural gas in the short and long run, correspondingly, are (0.17) and (0.38). Furthermore, Cross elasticity for electricity and gasoline in the long and short run, correspondingly, are substitute and complementary goods. In addition, the result of evaluating effect of the Targeting of Subsidies Plan show that estimated natural gas demand functions can explain the impact of this policy.

The present paper reviews the impact of the development situation of 3 groups of selected developing countries on environment over the period of 1990 – 2014 using by Environment Kuznets Curve (EKC) hypothesis. For this, it uses economic, social, human and political development factors with the variables that are as follows: GDP, GDP2 and energy consumption as economic development indicators, Urbanization as social and life expectancy at birth and fertility rates as human development indicators and good governance used as political indicator. The results show an inverted U-shaped relationship real GDP per capita and CO2 emission in oil-exporting and whole sample and a U-shaped in non-oil – exporting countries. In addition, the estimated results show a meaningful relationship between the CO2 emission and real GDP, energy use fertility rate, expectancy at birth and urbanization (development situation) in all three groups of the country.