In recent years substantial numbers of econometric papers have addressed estimation and inference methods of the THRESHOLD Auto Regression MODEL. THRESHOLD Auto regression MODEL are able to capture asymmetric and nonlinear movement of variables. This paper explains the characteristics of THRESHOLD MODELs and some different applications of these MODELs and then, investigates the THRESHOLD auto regression MODELs and MOMENTUM THRESHOLD auto regression MODELs. Finally, presenting some examples of THRESHOLD MODELs, we used the THRESHOLD co Integration test advanced by Enders and Siklos (2001) to investigate the asymmetric adjustment on long-run (PPP) in Iran between 1339 and 1390. Results prove PPP theory and imply that the adjustment process towards long run PPP is asymmetric.

In this article, the asymmetric co-integration of trade balance, export and import and exchange rate is investigated by applying Endres-Siklos Method, so TAR and M-TAR MODELs are used. The results of estimating the said MODELs show that there is an asymmetric co-integration between trade balance (non-oil), export (non-oil), import and exchange rate. Meantime, THRESHOLD Error Correction MODEL has been estimated to investigate short run dynamics of the said variables with regard to the exchange rate. The findings indicate that the main hypothesis of the MODEL, i.e. asymmetric co-integration between real exchange rate and trade balance, is approved. Furthermore, based on the results, the adjustment speed of the trade balance is higher when standing above its equilibrium point.

Financial markets are considered as a particular important capital market instruments an allocation of financial resources mobilization process. Considering the importance of strategic financial and economic market, when the disruption and diversion occur widely in it, mobilization and allocation of financial resources of the countries are faced with serious problems. One of the factors regenerator these issues is price bubble. Generally, when the price of a share is different from its future expected price, market bubble term is introduced. This paper explores validity of present value MODEL with time - varying expectations, by use of newly developed MOMENTUM THRESHOLD Cointegration test, M-TAR, to investigate if there is any asymmetric adjustment in long-run prices and dividends in Tehran stock Exchange during 2000: M3 to 2008: MIO? Empirical results indicate that long-run prices and dividends cointegration relationship doesn't hold for Tehran's stock exchange, which attests to the presence of rational bubbles.

The effect of exchange rate fluctuations on domestic prices plays a crucial role in designing and implementing macroeconomic policies. Thus, it is of great importance to discern the exchange market pressure, including the range of changes in foreign reserves and the exchange rates, as a measure to efficiently manage macroeconomics especially for developing economies. The present study aims to investigate and analyze the behavior of exchange market pressure in Iran in 1990-2012. To this goal, the exchange market pressure index has been computed using the procedures proposed by Edwards (2002) and Kumah (2007). With regard to the fact that the exchange market pressure index in Iran is nonlinear, the results of the analysis through the THRESHOLD Vector AUTOREGRESSIVE MODEL indicate that lagged variables have no significant effect on exchange market pressure when it is in a low regime, but, when the regime shifts towards a high pressure in exchange markets, the index for market exchange pressure increases. The findings also suggest that money growth and inflation have significant effects on exchange market pressure. Therefore, implementing contractionary policies in a monetary system as well as curbing inflation can regulate the pressure of the market exchange.

In this paper, we discuss the two-stage and the modified two-stage procedures for the estimation of the THRESHOLD AUTOREGRESSIVE parameter in a first-order THRESHOLD AUTOREGRESSIVE MODEL (${\rm TAR(1)}$). This is motivated by the problem of finding a final sample size when the sample size is unknown in advance. For this purpose, a two-stage stopping variable and a class of modified two-stage stopping variables are proposed. Afterward, we {prove} the significant properties of the procedures, including asymptotic efficiency and asymptotic risk efficiency for the point estimation based on least-squares estimators. To illustrate this theory, comprehensive Monte Carlo simulation studies is conducted to observe the significant properties of the procedures. Furthermore, the performance of procedures based on Yule-Walker estimators is investigated and the results are compared in practice that confirm our theoretical results. Finally, real-time-series data is studied to demonstrate the application of the procedures.

Market pressure is defined as a monetary problem caused by the excess demand or national currency supply and obliges monetary policymakers to use monetary devices to mitigate the disorders resulted from the fluctuations of national currency value. The present study aims to investigate the behavior of exchange market pressure (EMP)index in Iran’ s economy in the period 1990-4 to 2017-6 using three-regime Self-Exciting THRESHOLD Auto-Regressive MODEL (SETAR). With regard to the nonlinear nature of this index, the results indicate that the low regime of exchange market pressure includes a lower percentage of the observations in the period as compared to the higher regime. It can be concluded that the exchange market pressure has asymmetric behavior in Iran. On the other hand, the beginning of high exchange market pressure in the present decade and its repetition in these years suggests that Iran’ s economy has entered the high regime of exchange market pressure. In other words, the recent changes in Iran’ s economy, namely the sharp decrease of national currency value and high exchange market pressure, were predictable.

In this paper, an adaptive detection scheme for fluctuating targets with a swerling I MODEL in AR interference is presented. Since the proposed detector uses more information from the target signal in its structure, it has better performance compared with those detectors which do not use the target amplitude MODEL. Performance improvement of this detector compared with the previously AR MODEL based adaptive detector (ARGLR) is shown by simulation results. Besides, another detector is proposed for the known amplitude situation whose performance can be used as an upper bound for all similar detectors.

1- INTRODUCTION The enabling factor for entering the process of globalization is the creation of a competitive enviroment. The goal is to achieve competitive power through growth, development, and improvement in the quality of life. Competitiveness is the foundation for the economic growth of countries worldwide, and the real exchange rate is a good indicator for examination of a country's competitiveness in global markets. It is a variable through which we can assess the relative price of traded and non-traded goods. If there are no changes in the relative prices of other countries in the world and the real exchange rate decreases, it indicates a weakening of the international competitiveness of domestically produced goods. High fluctuations and lack of stability in real exchange rates can create an unstable environment for international trade and, as a result, reduce trade. Given the significance of the real exchange rate in influencing other macroeconomic variables and creating an uncertain environment, having knowledge of the future changes in the real exchange rate can play a crucial role in assisting monetary authorities to increase employment levels and stabilize prices. Since many microeconomic and macroeconomic variables are influenced by the exchange rate, a proper understanding of the linear or nonlinear behavior of the exchange rate can help policymakers, firms, and traders make accurate decisions in order to effectuate desired changes.   2- THEORETICAL FRAMEWORK The relationship between the national currency and the value of the national currency against foreign currencies is called the exchange rate. In international banking, the term "currency" refers to foreign money, sometimes including the adjective "foreign" to distinguish it from the domestic or local currency of a country. Currency is not limited to banknotes issued by central banks. It includes documents such as checks, drafts, and promissory notes that are used for international payments. Due to resource allocation based on relative prices in the free market, efficient resource allocation occurs when relative prices are properly adjusted and serve as an indicator of the real value of resources. The exchange rate is one of the most important prices, and deviations from equilibrium can disrupt the prices of other goods and services. Generally, exchange rates are divided into several categories: 1) Nominal exchange rate, 2) Real exchange rate, 3) Effective nominal exchange rate. The nominal exchange rate is the price of one unit of a currency in terms of another currency on a specific day and at a specific time. The mention of a specific time is necessary because the exchange rate may change during different hours of the day. It is common to express the price of one unit of foreign currency in terms of domestic currency in exchange rate calculations. Changes in the real exchange rate have a significant impact on the balance of payments and the international competitiveness of a country. Economists agree that an inappropriate level of stability for the real exchange rate leads to a decrease in national welfare. Thus, the instability of the real exchange rate from its equilibrium level leads to severe imbalances in the economy.   3- METHODOLOGY To investigate the nonlinear behavior of the real exchange rate in Iran and in order to examine the nonlinear behavior of the real exchange rate in Iranian economy during the years 2004:04- 2018:02 two MODELs have been applied: Self-Exciting THRESHOLD AUTOREGRESSIVE (SETAR) MODEL and Logistic Smooth Transition AUTOREGRESSIVE (LSTAR) MODEL.   4- RESULTS & DISCUSSION The possibility of THRESHOLD behavior in the real exchange rate has been confirmed by Broock, Dechert, and Scheinkman (1987) and Hansen (1999) test. Subsequently, the THRESHOLD values for the growth of the real exchange rate were calculated to be 3.84% in the first MODEL (SETAR) and 5% in the second MODEL (LSTAR). In the first MODEL, when the growth rate of the real exchange rate is below 3.84%, the growth rate of real exchange rate is minimal and classified as a regime with low growth. If the growth rate of the real exchange rate exceeds the THRESHOLD value (3.84%), its stability increases. In other words, when the growth rate of the real exchange rate is severe in Iran's economy, it is expected to be stable. In the second MODEL, values less than 5% are classified as a regime with low growth, while values greater than 5% are classified as a regime with high growth. The estimated coefficients for different orders in the two regimes indicate that if the growth rate of the real exchange rate is greater than 5%, this variable will exhibit stable behavior. However, at values below the THRESHOLD, due to the insignificance of the coefficients, this property will not be applicable.   5- CONCLUSIONS & SUGGESTIONS The results demonstrated the possibility of nonlinear behavior in the growth rate of the real exchange rate. After calculating the optimal order for AR and considering other econometric requirements (Hansen test), two MODELs, namely SETAR and LSTAR, were estimated. The THRESHOLD value was calculated to be 3.84% for the first MODEL and 5% for the second MODEL. In both MODELs, it was observed that as long as the growth rate of the real exchange rate remains in a severe regime, it exhibits significant stability and is positively influenced by its past values.