جستجوی مقالات مرتبط با کلیدواژه « شبیه سازی » در نشریات گروه « اقتصاد »

Applying a favorable tax system has important conditions such as justice and efficiency, therefore, consumption tax and income tax will comply with the principles of benefit and ability to pay. In this regard, value added tax is known as the most important innovation of the 20th century in terms of tax collection on consumption. Since increasing government revenue is one of the important goals of imposing this type of tax, the government has tried to determine the rate of this type of tax effectively and efficiently. Disproportionate increase in value added tax rates can have negative social effects on inflation, economic growth, income distribution, and general well-being in society. It may also have disruptive effects on other variables and sectors of Iran's economy. To manage the rate increase, one approach is to simulate and examine its consequences and effects on macroeconomic variables in the form of a multi-regional calculable general equilibrium model (MRCGE). Three different scenarios were applied and examined to simulate the shock effects of the increase in the value-added tax rate (12% , 15% , and 20 %) on four macro variables of Iran's economy: inflation, gross domestic product, consumption, and investment.  The simulations were conducted at the country level using a multi-regional calculable general balance model, known as the ORANI-G Iran model, using the 2016 input-output table and regional accounts of the country. The results indicate that the effect of increasing the tax rate on value-added will increase inflation and investment and decrease GDP and consumption.

There is good reason to expect crude oil prices to follow nonlinear models. However, previous research has considered the linear assumption to investigate the existence of a unit root. Unit root linear tests such as ADF, PP, and KPSS are provided for linear models. These tests are not suitable for nonlinear time series. Because the model deviation from the linear state may be considered as a random permanent deviation. The purpose of this article is to test the nonlinear unit root of crude oil prices, specifically Brent and WTI oil in the period 2019-2020 daily. For several decades now, various classes of nonlinear models have been introduced. These models introduce a wider range of dynamics than linear models in time series. A special type of these models that economists pay attention to are TAR models. In these models, as in linear models, valid statistical analysis requires distinguishing between the deterministic trend and the stochastic trend. In this study, the Bayesian unit root test for the general SETAR (1) model has been used with respect to the necessary and sufficient conditions for the maintenance of SETAR processes based on the article by Petrocyl and Wolford (1984). A nonlinear unit root test was performed using Bayesian validity interval. The results show that Brent crude oil prices in both regimes contain a unit root that is consistent with similar findings for the production or consumption of crude oil..

The purpose of this paper is to examine how money is created by recording accounting events in the balance sheets of banks. Therefore, a hypothetical economy, comprised of a central bank, a gharzolhasaneh bank, a commercial bank, and the people has been simulated. We pay special attention to special accounting records in the balance sheet of a commercial bank, interest rates and deferred bank loans in the banking system and their effect on the money creation process.  According to the results, the combined use of accrual basis of accounting in identifying uncollected facility income and cash basis of accounting in the payment of interest on deposits in a commercial bank leads to the money creation in the banking system and the higher the interest rate on deposits, the more money will be created. This will not happen in gharzolhasaneh Bank due to non-payment of interest on deposits and non-use of accrual basis of accounting system in identifying the income of paid loans. Also, in case of non-repayment of granted facilities and creation of deferred bank loans, the accrual basis of accounting system allows the commercial bank to continue the process of identifying facility income and paying unrealized interest on deposits, and interest paid on deposits enters the banking system as the new created money.

project portfolio management is a framework for integrated management of projects to achieve strategic goals of companies, considering the constraints. Its significance is more apparent in uncertain conditions that prevails in Iran's oil and gas industries, which confronts with capital constraints, sanctions, and economics fluctuations. The itroduced framework in this research encompasses the identification and definition of various scenarios for each oil and gas field, determination of mathematical model parameters, necessary data for calculating the model parameters, and the process and methods for their identification. Ultimately, it leads to the development of a mathematical model, which is the distinctive aspect of this study. The research, in terms of objective, is an application with a modeling and mathematical simulation approach, to providing a model for selecting an optimal portfolio of investment projects for upstream oil and gas companies under uncertainty conditions. After collecting the required data, the mathematical programming model was designed as an integer zero-one programming model with an objective function to maximize the net present value of different field scenarios, considering investment constraints and other binding constraints. The coding of the above model was executed and the intended simulation for uncertain parameters was performed using the CRYSTALL BALL software.

Public transportation system plays an important role in economic growth and urban development, including reducing transportation costs and increasing efficiency. To increase the share of public transportation systems in urban travel, measures need to be taken to improve their management and increase their efficiency. In this regard, the most important step in planning for this area is to revise or redefine the routes of the network lines. This process is known as a strategic step in managing long-term programs for the network. Given the growing trend of urbanization in large cities and the need for reliable and efficient public transportation, optimizing and improving the performance of public transportation networks is of great importance. Efficient planning and operation of transportation systems require accurate estimation of passenger waiting times. In this article, using a queuing system, simulation and optimization of urban public transportation system have been investigated with a case study of the Isfahan Bus Company in order to reduce waiting times at bus stops. In this study, first, the current performance of Isfahan's public transportation network was examined using simulation, and then by making changes to the network and various parameters, optimal solutions for reducing waiting times were proposed. The results of the simulation of Isfahan's bus transportation system show that significant improvements in the performance of the public transportation network can be achieved by making corrective changes to the structure and scheduling of the buses.

This article is devoted to the study of the impact of a reform in power plant fuel prices on the key variables of Iran's electricity market (average electricity price and the financial balance of the electricity industry). It is based on a simulation model. In this regard, we employed a model in which the presence or absence of competition in the electricity market is based on the amount of power plant storage factor that is available in every hour. The corresponding critical storage factor, which is based on actual operation, is also calculated. Due to a suppressed price cap and availability rate (that is even lower than what is necessary for sending optimal investment signals), the current price cap and availability rate is not a valid starting point for calculating the desired effects. Hence, before examining the effects of a price reform on the mentioned variables, the price cap and availability rates need to be adjusted to a level that can guarantee a minimum IRR for investors in this sector. According to calculations, in order to sending the necessary signals for investment, by assuming a fixed availability rate, it is necessary to increase the current price cap (nearly 417 Rials per kilowatt hour) to a new level (570 Rials per kilowatt hour). According to that, the average wholesale market price will increase from nearly 600 Rials per kilowatt hour to 706 Rials per kilowatt hour. The implementation of this policy imposes a financial burden of about 29894 billion Rials to the Ministry of Energy. Given that, in markets amid with a price cap (and hence an availability payment), a price reform in fuel price, requires a proportional modification in the market price cap. Based on this obligation, the effects of the price reform on the mentioned variables, is calculated and analyzed. The analysis is based on three different scenarios about fuel price for power plants; The price of gas used in the petrochemical industry (as a raw material for this industry), the price of gas that is exported to Turkey, and, the minimum bound foreseen in the "law on the targeting of subsidies" in relation to the price of natural gas. Implementation of the mentioned scenarios will increase the market cap from 570 Rials per kilowatt hour to 1783, 3655 and 2830 Rials per kilowatt hour respectively. Adjusted average market price, proportional to the adjustment made in the market price cap, would be equivalent to 1922, 3801 and 2973 rials per kilowatt hour respectively. Furthermore, the financial burden corresponding to these scenarios will be 61717, 156574 and 114866 billion Rials respectively.

In recent years, the use of effective risk management techniques in financial institutions, especially banks, has become more important. One of the methods related to this approach, which is very important for effective risk management; It is stress test. This test is considered a complementary tool along with other risk management tools, which determines the amount of capital required by banks and credit institutions to safely face various shocks, for example, macroeconomic shocks and cover the losses caused by these shocks. Empirical studies in recent years show that economic conditions are the cause of financial crises and also the emergence of liquidity risk in the banking system. In this article, by selecting 18 banks of the country and using the information of their financial statements in 54 quarterly periods from 2008 to 2021, stress test of banks' liquidity risk in the conditions of crisis and economic shock has been investigated, which includes two stages; In the first stage, the impact of effective factors such as macro variables and banking variables on liquidity risk has been modeled with a basic dynamic panel regression model, and in the next stage, with making scenario in terms of Basel III, the impact of macro variables' shock on banks' liquidity risk has been investigated to examine the ability and resistance of banking network in the conditions of tension and crisis. In the following, by using the Monte Carlo simulation and by calculating the value at risk of liquidity risk for at least one year after the estimation period, the loss of banks' liquidity risk in the face of shocks has been obtained. The results of stress test show among the shocks of macroeconomic variables, the shock of exchange rate has the greatest impact on banks' liquidity risk. Therefore, by considering effective factors among shocks, not only can financial crises be controlled, but it can be a precursor to the empowerment of banks before the occurrence of any type of shock in macroeconomic conditions.

Hubert's theory showed US oil production on a bell-like curve in 1956 and was introduced in the energy economics literature. This theory shows the lifespan, time trend and peak production of hydrocarbon reserves. In this research, the gas production from independent offshore gas fields, which provide about 60% of the country's natural gas production, was simulated. To compensate for the theoretical limitations of Hubert's model for not considering the dynamics in the ultimate recoverable reserves, the production process and cumulative production, the System Dynamics methodology were used. The model was used to simulate the production volume ​​and present worth of the national wealth of gas produced from independent offshore fields. The simulation results indicate that in the base scenario, the peak production is in the year 1413 (Persian calendar) by 2263 million cubic meters per day of gas production, and the present value of the accumulated produced gas will be $1354 billion at a price of the year 1401. The simulations results show that extraction with an annual growth rate of 13% (average from the year 1390 to 1396) would only be possible up to the year 1404. Each one per cent increase in the recovery factor adds $11 billion to the present value of accumulated production, and a leakage of 10% of the recoverable reserves would cause an economic loss of $87 billion to the national wealth.

Human Development Index is a composite one to measure three criteria of longevity, access to knowledge and appropriate level of welfare. Since 2011, education, the combination of mean study years for adults (25 years of age and elder) and expected years of studying, life expectancy and income per capita have been considered as components of Human Development Index. Human Development Index is in fact the geometrical mean of these three indexes. This index is annually calculated for countries by the United Nations but not for their states, provinces, cities and regions. Therefore, researchers themselves must calculate this index for provinces for certain purposes.

Lack of such statistics is also a statistic deficit in Iran that has made regional and provincial researches limited and inaccurate. To remove this deficit in this research Khouzestan Human Development Indexes in the years 1996, 2006, 2011 and 2016 have been calculated using the latest formula. It needs to be mentioned that the simulation of Human Development Index is difficult and time consuming. Not paying attention to details can deviate the index. So in order to ensure the precision of calculations, the Human Development of the country has also been calculated and compared with the same index calculated by the United Nations for Iran in order to ensure the authenticity of Human Development Index in Khouzestan. The applied method was a simultaneous behavioral pattern which considers the changes in Human Development Index through components of the United Nations Human Development Index and also simultaneously predicts and includes it in Human Development Index. The estimation method is based on Stock and Watson (1993) Dynamic least squared method that is helpful for predicting variables.

According to results, Khouzestan Human Development Index for the period 1990-2019 can be simulated. The related results are presented in table 1.Table 1. Simulation of Khuzestan Human Development Index results  As table 10 shows, Khouzestan Human Development Index had a slow rising trend up until 2005 but from 2006, there seems to be a jump or structural failure in Human Development Index. However, during 2016-2018 the trend reached a plateau and it seems to have reached its stabilized level. Also, based on this simulation Khouzestsan Human Development Index was in an average level up until 2008 but since 2009 it has reached its high.

To assess this hypothesis, in this research using the new formula Khouzestan Human Development Indexes for the years 1996, 2006, 2011 and 2016 were calculated. The results showed that the indexes of life expectancy and education in Khouzestan were in a worse situation than that of the country but the index of income (taking oil into account) was more than that of the country. The calculation of Khouzestan Human Development Index without oil showed a worse situation than that of the country.Based on results, Kouzestan Human Development Index reached from an average level in 1996 to a high level during 2006 to 2016. This is an acceptable growth. Also, Khouzestan Human Development Index without oil is lower than that of the national index and this represents the worse status of the province compared to the country.The results of simulating Human Development Index show that up until 1389, there was a slight rising trend but from this year on there has been a jump or failure. Moreover, Khouzestan Human Development Index was in an average level up to 1385 but it has reached a high one since 2010.

This research presents a method in sizing a combined on-grid battery and PV system with the aim of providing the needs during the peak load of the network and then estimating the cost and determining the amount of fair subsidies from the government. PV and battery systems that are used in many home, office and commercial sectors today are often connected to the national grid and PV and battery systems are considered as backup systems. The important function of such a system, apart from supplying electricity in the event of a nationwide power outage, is to minimize the cost of electricity consumption by reducing the power consumption during the peak. On the other hand, the function of such systems is to reduce the amount of electricity consumption from the network and reduce the pressure on the network. The first step in installing these systems is to obtain the right size for PV and batteries so that the household load is consumed during the peak and thus minimizes the costs. Then, the cost of the optimal size is calculated, and according to the 4-year return on investment period, the amount of subsidy that the government has to pay for the installation of these systems is calculated. In this paper, we try to simulate the consumption load of a residential house to obtain the appropriate capacity for the PV system and batteries in order to meet the mentioned result.

Identifying the behavior of business cycles and factors affecting business cycles has always been one of the most important issues in macroeconomics. Importance of business cycles and the unique economic structure of OPEC member countries, so, this article identifies the behavior of business cycles in these countries. This study uses Quantile Panel Regressions Model to examine the impact of variables such as government expenditure, trade openness, liquidity growth, oil prices and two dummy variables of the global recession and the Joint Comprehensive Plan of Action (JCPOA) agreement on the formation of business cycles in OPEC countries in the period 2000-2019. The results show that the values of the coefficients of each variable in different quantiles were significantly different from each other. Government expenditure and trade openness in the initial quantile has been in the agreed direction to the cycles and the End quantile opposite direction. The results of the effect of liquidity growth show that in the initial and end quantile has been agreed with direction to the cycles and in the middle quantile opposite direction to the cycles. Oil prices have also been agreed with the direction of the business cycles. The Joint Comprehensive Plan of Action (JCPOA) agreement variable in the first quantile has a significant impact on business cycles and the global financial recession has also acted against cycles.

Drugs as a strategic and subsidized commodity and an urgent need for patients have been constantly of particular importance, specially, in the health-care system of a society. On the other hand, one of the parameters concerning the assessment of the family welfare is the amount spent for satisfaction of divergent needs. The more a family spends on essential necessities such as food, housing, clothing and higher education, the less is expected to be devoted to health care. Concerning drugs, the demand for different drugs may vary depending on the patientschr('39') attitudes, the type of illnesses and their income elasticity. The objective of the present research is to investigate the demand for orphan drugs for refractory diseases regarding various income groups in Iran applying Agent-based Models (ABMs). In this research, the behavior dynamics of the orphan drugs applicants and the diversity of their demands in miscellaneous price scenarios resulting from inflation and fluctuations in the exchange rate have been scrutinized in accordance with ABM. To this end, one thousand family applicants for orphan drugs, extracted from Iranchr('39')s statistics center, were categorized in five different income ventiles. Their reactions towards the increase of the price of the aforementioned drugs are predicted based on Net Logo simulation software. The results indicate that the average of price elasticity of demand for generic and branded drugs has been -0.39 and -0.05 percent, respectively; similarly, the demand for these two drug groups has been decreased by the same amount. In the lowest income ventile as the price of generic and branded orphan drugs deceases, for the lowest income ventile families, the allocated expenses for these drugs has been decreased by 3.3 percent and 31.85 percent, respectively. The main reason for the aforementioned problem is assigned to the low budget of the patientschr('39') family and its allocation to essential necessities of life such as food and housing. The severity of the cost reduction in branded drugs is due to the fact that it can be replaced by generic drugs.

The vision of the Islamic Republic of Iran in the 1404 horizon illustrates a bright future for the country, a program that is more qualitative than a little. To achieve the objectives of the vision document, there is a need for a quantitative analysis of the indicators discussed in the document. To achieve this, economic exports as one of the major macroeconomic indicators have been simulated and predicted by Pso algorithms for Iran and Turkey. Using the bands pattern, using the four criteria of mean deviation (MSE), root mean square deviation (RMSE), absolute error percentage (MAPE) and absolute error (MAE) simulation have been performed. The results indicate that the gap between exports of  two countries has continued since 2000, with the current trend of Turkey's exports going to double the export of Iran's economy.

Focusing on financial performance indicators, the present study simulates possible strategic choices of businesses in managing organizational processes in a situation where the industry is experiencing a decline (demand decline) using a system dynamics approach. The system model and causal relationships of its variables are modeled according to the experimental foundations of the research and are simulated and analyzed using the system dynamics approach in the software environment. The results of research consistent with previous studies indicate that strategic decisions in the management of organizational processes should be made according to financial indicators. Implementation of different scenarios regarding the location of consumption of resources derived from business activities, focusing on financial indicators of return on equity, total fixed capital, amount of borrowed cash and asset index minus debt indicates that the cost of this Resources in internal processes (short-term investment), resource extraction and profit sharing, and finally, investments in equipment and machinery can be given the highest priority, respectively.

Theoretical studies show that the wavelet method is a suitable mathematical tool for analyzing signals and displaying them at different levels. At the same time, the wavelet method includes the order of waves and different tools for smoothing the series. Studies have shown that orthogonal walvelets including Haar, Daubechies, Symmelets, Coiflets, and Biorthogonal are the best types of wavelets. On the other hand, each type of wavelet is divided into different  orders, which is defined once for Haar wavelet, nine times for Daubechies wavelet, seven times for Symmelets wavelet, five times for Coiflets wavelet, fifteen times for Biorthogonal wavelet. Given that each of wavelet orders can be considered as a single wavelet, for orthogonal wavelets alone, thirty-seven wavelet types can be selected. On the other hand, for each type of wavelet, up to ten levels of decomposition can be performed, and each level of decomposition shows the process of economic trend in a different way, which means that a series can be decomposed into three hundred and seventy series. Economically, this means that 370 types of economic cycle formulas could be defined to examine a time series such as Gross Domestic Product (GDP), each of which would certainly have different results and interpretations. This is very sensitive in short-term and long-term economic planning.Given that no research has been done on the superiority of the wavelet type in economic projects, many studies have been erroneous due to a lack of attention to the following questions, though valuable. 1- What is the definition of process and cycle? 2- What is the most suitable type of wavelet? 3- Which wavelet order is more suitable? 4- Which wavelet level is more suitable?  To answer these questions using the method of orthogonal wavelets of Haar, Daubechies, Symmelets, Coiflets, and Biorthogonal with a maximum of 5 levels, the best type, order, and level of the wavelets are investigated in order to smooth the business cycles in Iran during the seasonal period of 1367-1397 by applying retrospective simulation (ex-post) method and correlation analysis using MATLAB software. The results show that bior 2.2 wavelet has the highest quality in the analysis and smoothing of business cycles in Iran. Based on these results, the seasonal GDP logarithm series, decomposed using the bior 1.1 wavelet at level 2, has the highest quality of all wavelets in analyzing and smoothing economic data. The wavelets bior 2.2_l4, bior 2.2_l1, bior 3.1_l4, bior 2.2_l3, and bior 3.1_l5 are ranked second to sixth. Moreover, regardless of the type of wavelet, level 4 has the highest repetition in all levels and in this respect, it is considered the best level of analysis. Therefore, it is recommended to select the low selective wavelet level (maximum 3) when using annual data, and the high wavelet level (minimum more than 4) if the data is monthly or seasonal. Moreover, the estimation of Iran's business cycles shows that in the research period, there were 16 business cycles, which were the most consecutive years of recession related to the years 1380-82, 1387-89, and 1391-93.

The conflict between the increase in production welfare and the decrease in welfare due to negative environmental externalities has called into question the idea of maximizing welfare as a result of increased production and has provided the ground for further studies. The purpose of the present study is to evaluate the pathways of economic growth when pollution externality is produced by using of a dynamic system model. The model assumes that some of the income will be expenditure to reduce pollution. The positive effect of utility and the negative effect of pollution are reflected in the welfare function. In the present study, the trend of variables over a period of 50 years is examined. The simulation results show that with increasing investment in improving environmental quality to reduce pollution, pollution and the present value of pollution damage increases and the present value of utility and accumulated welfare decreases. Therefore, policymakers should pay particular attention to environmental pollution and their environmental damages and increase the rate of investment in environmental pollution control. Because the rate of increase in pollution is higher than the rate of increase in investment in pollution control.

This study tries to predict the rental rates in district six of Isfahan for five years in the future by using an agent-based model. According to this simulation, district of Hezar Jerib has the highest and Hemat Abad has the lowest rental rate. Districts of Sa'adat Abad, Abshar, Baghnegar, Feiz, Masjed Mosala, Kuye Emam, Takht-e Foulad and Shahid Keshvari are followed by the district of Hezar Jerib. From the demand point of view, the high rental rate in Hezar Jerib district is due to higher comfort index in that region. From the supply point of view, the high rental rate in Hezar Jerib district is due to low supply of residential units.

This study aims to introduce the microstructure approach to the exchange rate as the 4th generation of exchange rate models and to apply it in a simulation model to study the effects of transparency of macroeconomic data on exchange rate fluctuations. The microstructure approach to the exchange rate is developed to include decentralized and multi-layer structure of currency markets along with information complexities in this market and the role of trading mechanisms in exchange rate determination. After introducing this approach, we have developed our theoretical model to use it for simulation. In this simulation, we have studied the effects of transparency of macro data release on exchange rate fluctuation. To achieve this goal, we have used two variables of “delay in macro data release” and “error in macro data release”. Our simulation results show that an increase in macro data release delay leads to higher volatility of The exchange rate. This is because of increasing uncertainty for economic agents. In addition, an increase in macro data release delay leads to a farther delay in responsiveness of the exchange rate to movements in its macro fundamental variables. Although we have found a non-linear relationship between  the “error in macro data release” variable and exchange rate volatility, the magnitude of this effect is less than the effect of the “delay in macro data release” variable on exchange rate volatility. Based on our results, we recommend that to have lower exchange rate volatility, authorities should increase the transparency of macroeconomic data releases and especially they should lower the delay in macro data releases.

Systemic risk is the risk beared by an economic system because of a special organization. This means that a liquidity problem or a financial crisis in one company could trigger a chain of reactions that puts the whole market into trouble. This kind of risk was underestimated until 2008 financial crisis. Now federal regulations exist for controlling this risk of financial institutions. Among diversified methods of systemic risk evaluation, centrality measures have the most accuracy. In this paper, we apply a combined method of systemic risk evaluation using semi-central centrality and Markov clustering method. Results show outperformance of proposed method over classic criterion CoVaR.