• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.324-329
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• 2005

In this paper, a robust $H\infty$ stabilization problem to a uncertain discrete-time nonlinear systems with time-delay via fuzzy static output feedback is investigated. The Takagj-Sugeno (T-S) fuzzy model is employed to represent an uncertain nonlinear system with time-delayed state. Then, the parallel distributed compensation technique is used for designing of the robust fuzzy controller. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust $H\infty$ controllers are given in terms of linear matrix inequalities via similarity transform and congruence transform technique. We have shown the effectiveness and feasibility of the proposed method through the simulation.

• Journal of Preventive Medicine and Public Health
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• v.44 no.6
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• pp.249-259
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• 2011

Objectives: This study aimed to analyze long-term trends in the contribution of each cause of death to socioeconomic inequalities in all-cause mortality among Korean adults. Methods: Data were collected from death certificates between 1990 and 2004 and from censuses in 1990, 1995, and 2000. Age-standardized death rates by gender were produced according to education as the socioeconomic position indicator, and the slope index of inequality was calculated to evaluate the contribution of each cause of death to socioeconomic inequalities in all-cause mortality. Results: Among adults aged 25-44, accidental injuries with transport accidents, suicide, liver disease and cerebrovascular disease made relatively large contributions to socioeconomic inequalities in all-cause mortality, while, among adults aged 45-64, liver disease, cerebrovascular disease, transport accidents, liver cancer, and lung cancer did so. Ischemic heart disease, a very important contributor to socioeconomic mortality inequality in North America and Western Europe, showed a very low contribution (less than 3%) in both genders of Koreans. Conclusions: Considering the contributions of different causes of death to absolute mortality inequalities, establishing effective strategies to reduce socioeconomic inequalities in mortality is warranted.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.367-377
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• 2018

This study introduces a DC resistivity inversion method that incorporates structural and inequality constraints to enhance the resolution of resistivity inversions, and presents sample inversion results with these constraints. In the constrained inversions, a base model is constructed from a layered model through interpretation of other geophysical data. Inversion tests establish that both the structural and inequality constraints produce better resistivity models than the unconstrained inversion. However, the inequality inversion not only reproduces the exact layered structure of the background, it reproduces conductive anomalies at a depth of ~ 10 m when an inexact base model of electrical resistivity is used.

• Journal of Korea Technology Innovation Society
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• v.12 no.3
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• pp.457-470
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• 2009

This paper applies a income mobility method to technology inequality using conditional human capital stock and shows their empirical results during the 1980 to 2000. There are several interesting empirical results coming out this analysis. Among the results, the paper turns out that world technology inequality mobility measurement is significantly higher for rapid formation of human capital stock countries than for slow formation of human capital stock countries. This paper, therefore, suggests that technology policy need to focus on improving the public education structure to recover the rate of return to human capital investment and to speed up technology development and deployment in Korea.

• Journal of Preventive Medicine and Public Health
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• v.40 no.5
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• pp.381-387
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• 2007

Objectives: This study was conducted in order to determine how the association between socioeconomic position(SEP) and health status changes with age among Seoul residents aged 25 and over. Methods: We utilized the 2001 and 2005 Seoul Citizens Health Indicators Surveys. We used self-rated 'poor' health status as an outcome variable, and family income as an indicator of SEP. In order to characterize the differential effects of socioeconomic position on health by age, we conducted separate multivariate analyses by 10-year age groups, controlling for sociodemographic covariates. In order to assess the relative health inequality across socioeconomic groups, we estimated the Relative Index of Inequality (RII). Results: The risk of 'poor health' is significantly high in low family income groups, and this increased risk is seen at all ages. However, the magnitude of relative socioeconomic inequality in health, as measured by the odds ratio and RII, is not identical across age groups. The difference in health across income groups is small in early adulthood (ages 25-34), but increases with age until relatively late in life (ages 35-64). It then decreases among the elderly population (ages more than 65). When the RII reported in 2005 is compared to that reported in 2001, RII can be seen to have increased across all ages, with the exception of individuals aged 25-34. Conclusions: The magnitude of health inequality is the greatest during mid- to late adulthood (ages 45-64). In addition, health inequalities have worsened between 2001 and 2005 across all age groups after economic crisis.

• Korea journal of population studies
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• v.28 no.2
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• pp.245-257
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• 2005

The income of wage earners and the transition of the inequality of their income from 1993 through 1998 have been analyzed. Korea's economy went through an epochal change since the beginning of the IMF economy and the inequality of income, which is part of the change incurred by this situation, has been studied in this thesis. The 'human capital theory' has been chosen as the basis of study. Also, gender, educational background and age, which are the key variables of the 'human capital theory', have been set as independent variables to compare each variable's influence in the distribution of income. From 1993 to 1998, the effect of gender has shown a fluctuating pattern whereas the effect of education declined slowly and the effect of age rapidly. The accumulative effect of the three variables show a fluctuating pattern, but at a declining mode. Though discrimination against gender, educational background and age, in terms of income, is at a declining mode, it is apparent that it still exists. Especially, discrimination against gender is continuing at a fluctuating pattern.

• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.359-365
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• 2005

Objectives : An abrupt economic decline may widen the socioeconomic differences in health between the advantaged and disadvantaged in a society. The aim of this study was to examine whether the South Korean economic crisis of 1997-98 affected the socioeconomic inequality from all-causes and from cause-specific mortality between 1995 and 2001. Methods : Population denominators were obtained from the registration population data, with the number of death (numerators) calculated from raw death certificate data. The indicator used to assess the geographic socioeconomic position was the per capita regional tax revenue. Administrative districts (Si-Gun-Gu) were ranked according to this socioeconomic measure, and divided into equal population size quintiles on the basis of this ranking. The sex- and 5-year age-specific numbers of the population and deaths were used to compute the sex- and age-adjusted mortality rates (via direct standardization method), standardized mortality ratios (via indirect standardization methods) and relative indices of inequality (RII) (via Poisson regression). Results : Geographic inequalities from all-causes of mortality, as measured by RII, did not increase as a result of the economic crisis (from 1998-2001). This was true for both sexes and all age groups. However, the cause-specific analyses showed that socioeconomic inequalities in mortalities from external causes were affected by South Korean economic crisis. For males, the RIIs for mortalities from transport accidents and intentional self-harm increased between 1995 and 2001. For females, the RII for mortality from intentional self-harm increased during the same period. Conclusions : The South Korean economic crisis widened the geographic inequality in mortalities from major external causes. This increased inequality requires social discourse and counter policies with respect to the rising health inequalities in the South Korean society.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.439-445
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• 2018

This study was conducted to investigate the status of oral health behavior according to economic inequality in Korea. Raw data for the 3rd year (2015) of the 6th national health and nutrition survey were analyzed. Among surveyed individuals, adults over the age of 19 were designated as research subjects. The results indicated that a smaller 'house income' was associated with a higher supply and demand experience for basic living and a higher DMFT. Additionally, a higher DMFT was associated with a lower 'house income', lower 'education level', and the 'experience of basic living security received'. Oral health behavior inequality was caused by economic inequality. Overall, these results indicate that it is necessary for the oral health service of vulnerable groups to strengthen preventive activities through comprehensive arbitration policies regarding the social decision factors of public health projects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.502-510
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• 2021

This study examines gender inequality in the Utopian literature through Bellamy's novelLooking Backward: 2000-1887. Boston, USA, in 2000 is an equal society in which production and distribution are performed efficiently, and everyone can work with an equal opportunity without discrimination. But a closer look at the social structure shows that housework and parenting are predominantly women's duties, and the jobs that women and men can have are differentiating. Therefore, it is hard to say that true gender equality has been achieved. In addition, we could see that there were still remnants of gender inequality, such as showing the notion of beauty judged by male standards. However, Bellamy's Looking Backward: 2000-1887 is meaningful in that it improved women's status and suggested the direction and hope of social development in the 19th century. This study further examined whether these gender inequality factors have disappeared in modern society and confirmed that there remain many gender inequality factors. Therefore, we should all work together to improve the perception of members of society and make changes in social policies so that there is no discrimination between women and men so that we can truly become a gender-equal society.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1034-1040
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• 2018

Purpose: This study aimed to investigate inequalities in colorectal cancer (CRC) screening rates in Korea and trends therein using the slope index of inequality (SII) and relative index of inequality (RII) across income and education groups. Materials and Methods: Data from the Korean National Cancer Screening Survey, an annually conducted, nationwide cross-sectional survey, were utilized. A total of 17174 men and women aged 50 to 74 years were included for analysis. Prior experience with CRC screening was defined as having either a fecal occult blood test within the past year or a lifetime colonoscopy. CRC screening rates and annual percentage changes (APCs) were evaluated. Then, SII and RII were calculated to assess inequality in CRC screening for each survey year. Results: CRC screening rates increased from 23.4% in 2005 to 50.9% in 2015 (APC, 7.8%; 95% CI, 6.0 to 9.6). Upward trends in CRC screening rates were observed for all age, education, and household income groups. Education inequalities were noted in 2009, 2014, and overall pooled estimates in both indices. Income inequalities were inconsistent among survey years, and overall estimates did not reach statistical significance. Conclusion: Education inequalities in CRC screening among men and women aged 50 to 74 years were observed in Korea. No apparent pattern, however, was found for income inequalities. Further studies are needed to thoroughly outline socio-economic inequalities in CRC screening.