• Title/Summary/Keyword: coefficient bounds

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The Impact of Foreign Remittances and Financial Development on Poverty and Income Inequality in Pakistan: Evidence from ARDL - Bounds Testing Approach

  • Kousar, Rizwana;Rais, Syed Imran;Mansoor, Abdul;Zaman, Khalid;Shah, Syed Tahir Hussain;Ejaz, Shakira
    • The Journal of Asian Finance, Economics and Business
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    • v.6 no.1
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    • pp.71-81
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    • 2019
  • The objective of the study is to examine the impact of financial development and foreign remittances on poverty and income inequality in the context of Pakistan. The study used ARDL-Bounds testing approach for robust inferences. The results show that in the short-run, remittances increases poverty and income inequality, which further translated into its long-run impact. The result confirmed the inverted U-shaped relationship between per capita income and income inequality, while the second order coefficient of per capita income substantially decline poverty incidence in a country. In the long-run, the results disappeared and it's turned into U-shaped relationship between income inequality and country's per capita income. Education largely decreases income inequality both in the short and long-run, however, it increases poverty in the long-run. Unemployment rate substantially damaged the pro-poor growth scenario, as high unemployment rate increases both the poverty rates and income inequality, which suffered poor more than non-poor in a country. Financial development has a positive impact on poverty reduction and income inequality in the short-run. The impact of income inequality on poverty incidence is positive both in the short- and long-run, which need pro-poor growth policies and rationale income distribution in a country.

Beyond Growth: Does Tourism Promote Human Development in India? Evidence from Time Series Analysis

  • SHARMA, Manu;MOHAPATRA, Geetilaxmi;GIRI, Arun Kumar
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.693-702
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    • 2020
  • The present study aims to investigate the impact of tourism growth on human development in Indian economy. For this purpose, the study uses annual data from 1980 to 2018 and utilizes two proxies for tourism growth - tourism receipt and tourist arrivals - and uses human development index calculated by UNDP. The study uses control variables such as government expenditure and trade openness. The study employs auto regressive distributed lag (ARDL) approach to investigate the cointegrating relationship among the variables in the model. Further, the study also explores the causal nexus between tourism sector and human development by using the Toda-Yamamoto Granger non-causality test. The result of ARDL bounds test reveals the existence of cointegrating relationship between human development indicators, government expenditure, trade openness, and tourism sector growth. The cointegating coefficient confirms a positive and significant relationship between tourism sector growth and human development in India. The causality result suggests that economic growth and tourism have a positive impact while trade openness has a negative impact on human development in India. The major findings of this study suggest that tourism plays an important role in the socio-economic development of Indian economy in recent years and the country must develop this sector to achieve sustainable development.

An Error Assessment of the Kriging Based Approximation Model Using a Mean Square Error (평균제곱오차를 이용한 크리깅 근사모델의 오차 평가)

  • Ju Byeong-Hyeon;Cho Tae-Min;Jung Do-Hyun;Lee Byung-Chai
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.8 s.251
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    • pp.923-930
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    • 2006
  • A Kriging model is a sort of approximation model and used as a deterministic model of a computationally expensive analysis or simulation. Although it has various advantages, it is difficult to assess the accuracy of the approximated model. It is generally known that a mean square error (MSE) obtained from the kriging model can't calculate statistically exact error bounds contrary to a response surface method, and a cross validation is mainly used. But the cross validation also has many uncertainties. Moreover, the cross validation can't be used when a maximum error is required in the given region. For solving this problem, we first proposed a modified mean square error which can consider relative errors. Using the modified mean square error, we developed the strategy of adding a new sample to the place that the MSE has the maximum when the MSE is used for the assessment of the kriging model. Finally, we offer guidelines for the use of the MSE which is obtained from the kriging model. Four test problems show that the proposed strategy is a proper method which can assess the accuracy of the kriging model. Based on the results of four test problems, a convergence coefficient of 0.01 is recommended for an exact function approximation.

Maximum Braking Force Control Using Wheel Slip Controller and Optimal Target Slip Assignment Algorithm in Vehicles (휠 슬립 제어기 및 최적 슬립 결정 알고리즘을 이용한 차량의 최대 제동력 제어)

  • Hong Dae-Gun;Hwang In-Yong;SunWoo Myoung-Ho;Huh Kun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.3 s.246
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    • pp.295-301
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    • 2006
  • The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS systems. In order to achieve the superior braking performance through the wheel-slip control, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance, stability enhancement, etc. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm. An adaptive law is formulated to estimate the longitudinal braking force in real-time. The wheel slip controller is designed using the Lyapunov stability theory and considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm is developed for the maximum braking force and searches the optimal target slip value based on the estimated braking force. The performance of the proposed wheel-slip control system is verified In simulations and demonstrates the effectiveness of the wheel slip control in various road conditions.

Statistical Effective Interval Determination and Reliability Assessment of Input Variables Under Aleatory Uncertainties (물리적 불확실성을 내재한 입력변수의 확률 통계 기반 유효 범위 결정 방법 및 신뢰성 평가)

  • Joo, Minho;Doh, Jaehyeok;Choi, Sukyo;Lee, Jongsoo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.11
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    • pp.1099-1108
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    • 2017
  • Data points obtained by conducting repetitive experiments under identical environmental conditions are, theoretically, required to correspond. However, experimental data often display variations due to generated errors or noise resulting from various factors and inherent uncertainties. In this study, an algorithm aiming to determine valid bounds of input variables, representing uncertainties, was developed using probabilistic and statistical methods. Furthermore, a reliability assessment was performed to verify and validate applications of this algorithm using bolt-fastening friction coefficient data in a sample application.

A Study on Steady-State Criterion based on COV and a Fault Detection Method during GHP Operation (GHP 운전시 COV에 의한 정상상태 판별 및 이상검출 방법 연구)

  • Shin, Young-Gy;Oh, Se-Jae;Jeong, Jin-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.11
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    • pp.705-710
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    • 2011
  • Fault detection has to be proceeded by steady state filtering to get rid of transient effect associated with thermal capacity. Coefficient of variance (COV), ratio of standard deviation devided by moving average, was employed as steady-state filter. Engine speed and refrigerant pressures were selected as parameters representing system dynamics. The filtered values were registered as members of steady-state DB. They were found to show good functional relationship with ambient temperature. The relationship was fitted with a second order polynomial and the distribution bounds of the data around the fitted curve were expressed by visual inspection because of varying average and random data interval. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the fault-free one. To make such isolation reliable, tests to construct good DB should be designed in a systematic way.

Correlation Coefficients between Parametric and onparametric Test Statistics for Signal Detection Problems (신호 검파 문제에 쓰는 모수와 비모수 검정 통계량 사이의 상관계수)

  • Park So Ryoung;Kwon Hyoungmoon;Bae Jinsoo;Choi Sang Won;Lee Jumi;Song Iickho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.541-550
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    • 2005
  • In this paper, we address the derivation of joint distributions and correlation coefficients for four pairs of statistics used commonly in a number of signal detection schemes. The upper and lower bounds of the correlation coefficients are obtained, and interesting relationships between the correlation coefficients are derived. Explicit values of the correlation coefficients are given in the form of tables and figures for easy reference. The results in this paper should be useful in comparing various detection statistics.

MAXIMUM BRAKING FORCE CONTROL UTILIZING THE ESTIMATED BRAKING FORCE

  • Hong, D.;Hwang, I.;SunWoo, M.;Huh, K.
    • International Journal of Automotive Technology
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    • v.8 no.2
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    • pp.211-217
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    • 2007
  • The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

Tune of Hydrodynamic Coefficients Based on Empirical Formula by Using Manoeuvring Performance Indices of a Ship (선박 조종성능지수를 활용한 경험식 기반 유체력 미계수의 보정)

  • Kim, Dong Jin;Kim, Yeon Gyu
    • Journal of the Society of Naval Architects of Korea
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    • v.57 no.6
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    • pp.331-344
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    • 2020
  • Ship's hydrodynamic coefficients in manoeuvring equations are generally derived by captive model tests or numerical calculations. Empirical formulas have been also proposed in some previous researches, which were useful for practical predictions of hydrodynamic coefficients of a ship by using main dimensions only. In this study, ship's hydrodynamic coefficients based on empirical formulas were optimized by using its free running test data. Eight manoeuvring performance indices including steady turning radius, reach in zig-zag as well as well-known IMO criteria indices are selected in order to compare simulation results with free runs effectively. Sensitivities of hydrodynamic coefficients on manoeuvring performance indices are analyzed. And hydrodynamic coefficients are tuned within fixed bounds in order of sensitivity so that they are tuned as little as possible. Linear and nonlinear coefficients are successively tuned by using zig-zag and turning performance indices. Trajectories and velocity components by simulations with tuned hydrodynamic coefficients are in good agreements with free running tests. Tuned coefficients are also compared with coefficients by captive model tests or RANS calculations in other previous researches, and the magnitudes and signs of tunes are discussed.

Nuclear energy consumption and CO2 emissions in India: Evidence from Fourier ARDL bounds test approach

  • Ozgur, Onder;Yilanci, Veli;Kongkuah, Maxwell
    • Nuclear Engineering and Technology
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    • v.54 no.5
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    • pp.1657-1663
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    • 2022
  • This study uses data from 1970 to 2016 to analyze the effect of nuclear energy use on CO2 emissions and attempts to validate the EKC hypothesis using the Fourier Autoregressive Distributive Lag model in India for the first time. Because of India's rapidly rising population, the environment is being severely strained. However, with 22 operational nuclear reactors, India boasts tremendous nuclear energy potential to cut down on CO2 emissions. The EKC is validated in India as the significant coefficients of GDP and GDP.2 The short-run estimates also suggest that most environmental externalities are corrected within a year. Given the findings, some policy recommendations abound. The negative statistically significant coefficient of nuclear energy consumption is an indication that nuclear power expansion is essential to achieving clean and sustainable growth as a policy goal. Also, policymakers should enact new environmental laws that support the expansion and responsible use of nuclear energy as it is cleaner than fossil fuels and reduces the cost and over-dependence on oil, which ultimately leads to higher economic growth in the long run. Future research should consider studying the nonlinearities in the nuclear energy-CO2 emissions nexus as the current study is examined in the linear sense.