• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.135-142
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• 2009

In this paper the Simplified Refined Instrumental Variable (SRIV) identification algorithm for SISO systems is extended to MIMO systems described by a Left Matrix Fraction Description (LMFD). The performance of the extended algorithm is compared to the well-known MIMO four-step instrumental variable (IV4) algorithm. Monte Carlo simulations for different signal to noise ratios are conducted to assess the performance of the algorithm. Moreover, the algorithm is applied to a simulated quadruple tank process.

• Korean Journal of Logic
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• v.22 no.1
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• pp.183-209
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• 2019

In this paper, I first examine Reiss'(2005) arguments for the causal instrumental variable. Second, I argue that the conditions for causal transitivity I consider meet what the causal instrumental variables and the interveners of the manipulation theory of causation are intended to hold. Reiss shows that two conditions for instrumental variables are not sufficient for causal significance of independent variables for dependent variables. Reiss articulates and reformulates the conditions for instrumental variables in terms of the conditions on causality, while naming his instrumental variables as causal instrumental variables. Reiss argues that the causal instrumental variables are similar to the interveners of the manipulation, or intervention theory of causation. He further argues that the causal instrumental variables do a better job the interveners do. I argue that the conditions for causal transitivity I consider meet the goal the conditions for the causal instrumental variables and the conditions for the interveners both are intended to achieve.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.268-276
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• 2018

This study examined the effects of indemnity private health insurance on the medical utilization among the Korean adults. The used data were the 2014 survey data of Korea Health Panel, and the number of subjects was 11,436. Authors employed instrumental variable regression model where the instrument variables for controlling for endogeneity of indemnity were the purchasing of private pension and number of family members. The results showed that the number of outpatient visits and the number of hospitalizations for indemnity private health insurance subscribers were higher than non-subscribers. The number of household members and the private pension variables were proved to be appropriate as instrumental variables. This paper recommends the Korean government to monitor and evaluate the effects of indemnity private health insurance on the medical utilization in order to improve the efficiency of health care finance.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.1263-1268
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• 2021

This study investigates how dramatic increase of university and college graduates affects labor market outcomes. Using a series of seven repeated cross sections of the Vietnam Household Living Standards Surveys, this paper analyzed the changes in the rate of returns to higher education attainment along with the increased supply of university and college graduates due to the higher education expansion throughout the 2002-2014 period. The study utilized a ratio of number of university and college students to the number of upper-secondary pupils within each province as an instrumental variable to calculate the effects of higher education expansion on the labor wage. The study found that, with the basic equations, the coefficients for higher education attainment are statistically significant and have positive values for the whole period. Our instrumental variables were found to be valid. For instrumental variable estimation, the return to higher education in IV earning equations was quite high. The findings of this study suggested that the expansion of the higher education system in Vietnam during 2002-2014 had positive effects on wages for those who increased their education attainment due to the reforms and there was a declining trend of the returns to higher education toward the end of the period.

• Journal of Families and Better Life
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• v.14 no.2
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• pp.61-76
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• 1996

In this study it was assumed that planning was composed of three activities -resource assessment standard setting information seeking and implementing was composed of money investment and time investment, Two variable groups which were assumed to be related with planning and implementing were household characteristics and housewife's value characteristics. Money investment to children's education was significantly affected by income, net wealth of household instrumental value of eduation and information seeking about private education. The variables assumed to affect time investment to children's education were instrumental value of education information seeking about private education and expected education level.

• Journal of Labour Economics
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• v.38 no.1
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• pp.1-30
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• 2015

The aggregate matching function is estimated to explain dynamics among job seekers, vacancies and new hires in Korea. Due to measurement errors inherent in vacancies data, I introduce a latent variable for job openings and use the instrumental variables to correct its endogeneity. Matching efficiency is also estimated using some explanatory variables like job seekers' characteristics and public employment services. The result shows that Korea's matching function also exhibits a constant returns to scale.

• Journal of KSNVE
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• v.6 no.5
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• pp.679-684
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• 1996

The Instrumental Variable Method(IVM), modified from least square algorithm, is applied to parameter identification of a noise contaminated bearing test rig. The signal to noise ratio included in Frequency Response Function(FRF) can cause significant errors in parameter identification. Therefore, among several candidates of parameter identification method, results of the applied IVM were compared with noise-contaminated least square method. This study shows that the noise-contaminated least square method can have indonsistent accuracy depending on the degree of noise level, while the IVM has robuster performance to signal to noise ratio than least square method.

• KDI Journal of Economic Policy
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• v.38 no.4
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• pp.77-94
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• 2016

This paper examines the empirical magnitude of local human capital spillovers in Korea during the 1980s and mid-1990s. Local human capital spillovers exists if plants in regions with a higher level of human capital can produce more given their own amount of input (Moretti 2004c). In particular, this paper explores an educational reform in South Korea which exogenously induced a large amount of variation in regional human capital levels. Using annually collected plant level data, I explore the effect of changes in the regional human capital levels induced by this reform on plant productivity in Korea. My results suggest that this effect is limited. I find a positive correlation between a regional level of human capital and plant productivity. However, after further addressing endogeneity using an instrumental variable, the effect of the overall regional human capital level on productivity decreases and becomes statistically insignificant.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.354-362
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• 2000

This paper identifies a discrete-time linear combustion model of Refuse Incineration Plant(RIP) which characterizes steam generation quantity, where the RIP is considered as a MIMO system with thirteen-inputs and one-output. The structure of RIP model is described as an ARX model which are analytically obtained from the combustion dynamics. Furthermore, using the Instrumental Variable(IV) identification algorithm, model structure and unknown parameters are identified from experimental input-output data sets, In result, it is shown that the identified ARX model well approximates the input-output combustion characteristics given by experimental data sets.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.688-693
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• 2002

Identification method is formulated to evaluate the dynamic characteristics of air bearings under NFR(Near Field Recording) sliders. Impulse responses and frequency response functions of NFR sliders are obtained on numerical non-linear models including rigid motion of slider and fluid motion of air bearing under the slider. Modal parameters and system parameters are identified by modal analysis method and instrumental variable method. The parameters of sliders are utilized to evaluate the dynamic characteristics of air bearings. Also, this study shows the difference between the dynamic characteristics of NFR and HDD slides, and squeeze effect of air bearings.