• Journal of Preventive Medicine and Public Health
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• v.39 no.2
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• pp.115-122
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• 2006

Objectives : This study was conducted to examine the relationships of the several socioeconomic position indicators with the mortality risk in a representative longitudinal study of South Korea. Methods : The 1998 National Health and Nutrition Examination Survey was conducted on a cross-sectional probability sample of South Korean households, and it contained unique 13-digit personal identification numbers that were linked to the data on mortality from the National Statistical Office of Korea. Of 5,607 males and females, 264 died between 1999 and 2003. Cox's regression was used to estimate the relative risks (RR) and their 95% confidence intervals (CI) of mortality. Results: Socioeconomic differences in mortality were observed after adjustments were made for gender and age. Compared with those people having college or higher education, those people without any formal education had a greater mortality risk (RR=2.21, 95% CI=1.12-4.40). The mortality risk among manual workers was significantly greater than that for the non-manual workers (RR=2.73, 95% CI=1.47-5.06). A non-standard employment status was also associated with an increase in mortality: temporary or daily workers had a greater mortality risk than did the full-time workers (RR=3.01, 95% CI=1.50-6.03). The mortality risk for the low occupational class was 3.06 times greater than that of the high and middle occupational classes (95% CI=1.75-5.36). In addition, graded mortality differences according to equivalized monthly household income were found. A reduction of monthly household income by 500 thousand Korean Won (about 400 US dollars) was related with a 20% excess risk of mortality. Self-reported poor living standards were also associated with an increased risk of mortality. Those without health insurance had a 3.63 times greater risk of mortality than the insured (95% CI=1.61-8.19). Conclusions: This study showed the socioeconomic differentials in mortality in a national longitudinal study of South Korea. The existence of socioeconomic mortality inequalities requires increased social discussion on social policies in Korean society. Furthermore, the mechanisms for the socioeconomic inequalities of mortality need to be explored in future studies.

• 한국노년학
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• v.37 no.3
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• pp.727-745
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• 2017

This study purported to examine the effects of precarious employment and social capital on the changes of self-rated health status among the middle aged and the young-old population in South Korea. The study analyzed 12 year follow-up data generated by the Korean Labor and Income Panel Study(KLIPS 6-17), which included 10532 employed subjects aged 55 to 75. Multi-level growth curve modeling was performed by fixed and random effect models using STATA 13.0 program. Afterwards, Hausman test was performed, which resulted in support of the estimation by fixed effect model. The results showed that a day labor position was significant factor affecting the deteriorated changes of self-rated health status over time. In addition, wage, weekly working hours, and private/relational social capitals were also found to be significant factors affecting the changes of the self-rated health status. The results supported the divergence hypothesis as well as the cumulative advantage theory. Efforts should be made to develop and implement various employment support policies and social service programs to alleviate the health inequality of the employed workers over their middle-aged to young-old period.

• Journal of the Korean Society of Child Welfare
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• no.59
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• pp.115-150
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• 2017

The purpose of this study was to examine the current status of the Dream Start program from the perspective of social investment strategy, and as well as to suggest future directions. The program has become a major government welfare program in korea since it was introduced in 2007 as a demonstration project, following research evidence and a sound rationale about the extensive success of Head Start in the U.S. and Sure Start Programme in the UK. The aim of Dream Start is to provide integrated services for the vulnerable children, aged 0 to 12, and their families who are identified using a national administration data record of disadvantaged families with children. In order to promote the vulnerable child's well-being, to overcome inequalities, and to give every child the best start in life, Dream Start adopted a local, "whole family" approach. Case management services form an essential part of the Dream Start to customize and integrate comprehensive services such as counseling, health care, parenting advice and education, academic tutoring, and after-school activities. Although there has been a general improvement in key factors since its inception, Dream Start has not yet sufficiently shown the strong and hoped-for impact. In the meantime, Dream Start must be given financial expansion and extensive policy supports to get the chance of realizing and evaluating long-term gains for children and their families. More work need to be done to overcome inequalities and to make Dream Start service more accessible for the most disadvantaged families with children in Korea. Practical and policy suggestions for future directions of the Dream Start programs were discussed.

• 한국노년학
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• v.30 no.3
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• pp.779-791
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• 2010

This study was to examine the differential impacts of social experiences and conditions on health among men and women aged 65 years or older, using data of the "2004 Survey on living Status of the Korean Elderly". The outcome variables were any disability, self-rated health, multiple morbidity, and self-rated quality of life. Multiple Classification Analysis was used to test the differential exposure to social factors contributes to gender difference in health. Gender differences in vulnerability of each individual socioeconomic, psycho-social, and behavioral factors for health were assessed by comparing logit coefficients in men and women. I found that gender difference in exposure to social factors contribute to inequalities in health between older men and women, however, gender inequalities remained after controlling for differential exposure except in case of quality of life. In addition, gender differences in health were further explained by differential vulnerabilities to social factors between men and women. Findings of this study may affirm the importance of further and deeper investigation of gender differences in health in later life. Gender sensitive approach in health planning and polices for the elderly is also suggested.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.513-523
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• 2012

For precisely regulating the speed of a permanent magnet synchronous motor system with unknown load torque disturbance and disturbance inputs, an LMI-based sliding mode control scheme is proposed in this paper. After a brief review of the PMSM mathematical model, the sliding mode control law is designed in terms of linear matrix inequalities (LMIs). By adding an extended observer which estimates the unknown load torque, the proposed speed tracking controller can guarantee a good control performance. The stability of the proposed control system is proven through the reachability condition and an approximate method to implement the chattering reduction is also presented. The proposed control algorithm is implemented by using a digital signal processor (DSP) TMS320F28335. The simulation and experimental results verify that the proposed methodology achieves a more robust performance and a faster dynamic response than the conventional linear PI control method in the presence of PMSM parameter uncertainties and unknown external noises.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.1
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• pp.1162-1170
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• 2001

This paper proposes a practical gain-scheduling control law considering robust stability and performance of Linear Parameter Varying(LPV) systems in the presence of nonlinearities and uncertainties. The proposed method introduces LMI-based pole placement synthesis and also associates with a recently developed fuzzy control system based on Takagei-Sugenos fuzzy model. The sufficient conditions for robust controller design of linearized local dynamics and robust stabilization of fuzzy control systems are reduced to a finite set of Linear Matrix inequalities(LMIs) and solved by using co-evolutionary algorithms. The proposed method is applied to the longitudinal acceleration control of high performance aircraft with linear and nonlinear simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.524-529
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• 2004

In this paper, We described the method which developed the optimal control system for air separation unit to change production rates frequently and rapidly. Control models of the process were developed from actual plant data using subspace identification method which is developed by many researchers in resent years. The model consist of a series connection of linear dynamic block and static nonlinear block (Wiener model). The model is controlled by model based predictive controller. In MPC the input is calculated by on-line optimization of a performance index based on predictions by the model, subject to possible constraints. To calculate the optimal the performance index, conditions are expressed by LMI(Linear Matrix Inequalities).In order to access at the Bailey DCS system, we applied the OPC server and developed the Client program. The OPC sever is a device which can access Bailey DCS system.The Client program is developed based on the Matlab language for easy calculation,data simulation and data logging. Using this program, we can apply the optimal input to the DCS system at real time.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.619-624
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• 2011

This paper presents a controller design method for a robust control problem with multiple constraints using genetic algorithms and LMI design method. A robust $H_{\infty}$ constraint with loop shaping and pole placement is used to address disturbance attenuation with error limits and desired transient specifications, in spite of the plant uncertainties and disturbances. In addition, a loop gain constraint is considered so as not to enlarge the loop gain unnecessarily. The robust $H_{\infty}$ constraint and pole placement constraint can be expressed in terms of two matrix inequalities and the loop gain constraint can be considered as an objective function so that genetic algorithms can be applied. Accordingly, a robust controller can be obtained by integrating genetic algorithms with LMI approach. The proposed controller design method is applied to a track-following system of an optical disk drive and is evaluated through simulation results.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.19-27
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• 2004

A delay dependent fuzzy $H_2/H_{\infty}$ controller design method for delayed fuzzy dynamic systems is considered. Using delay-dependent Lyapunov function, the asymptotical stability and $H_2/H_{\infty}$ performance problem are discussed. A sufficient condition for the existence of fuzzy controller is presented in terms of linear matrix inequalities(LMIs). A simulation example is given to illustrate the design procedures and performances of the proposed methods.

• Research in Community and Public Health Nursing
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• v.26 no.2
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• pp.140-149
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• 2015

Purpose: This study was conducted to identify activities of daily living, depression and self-rated health and related factors for Korean Elderly. Methods: Data from the survey for the Korean Longitudinal Study of Aging in 2010 were used. The data were analyzed using frequencies, weighted proportions, and hierarchical multiple logistic regression. Results: Significant difference was observed in health status induced by socioeconomic status between men and women, but not among age groups. Socioeconomic status was strongly associated with self-rated health among male and female elders. Being unschooled and low net family asset were significantly related with dependency in activities of daily living and depressive symptoms among men. Only low net family asset was significantly related with depressive symptoms among women. Family support provides a slight decrease to the negative relationship between socioeconomic status and health status, especially depressive symptoms. Conclusion: This study suggests that interventions to reduce health inequalities should target elderly with lower socioeconomic status and with poor family support, using a gender-specific approach.