• Proceedings of the KSME Conference
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• 2004.04a
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• pp.828-833
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• 2004

The performance of a mixed $H_{\infty}/H_2$ design with pole placement constraints based on robust vibration control for a piezo/beam system is investigated. The governing equation of motion for the piezo/beam system is derived by Hamilton's principle. The assumed mode method is used to discretize the governing equation into a set of ordinary differential equation. A robust controller is designed by $H_{\infty}/H_2$ feedback control law that satisfies additional constraints on the closed-loop pole location in the face of model uncertainties, which are derived for a general class of convex regions of the complex plane. These constraints are expressed in terms of linear matrix inequalities (LMIs) approach for the multiobjective synthesis. The validity and applicability of this approach for vibration suppressions of SMART structural systems are discussed by damping out the multiple vibrational modes of the piezo/beam system.

• Journal of the Korean Geographical Society
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• v.45 no.4
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• pp.478-501
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• 2010

The purpose of this study is to understand spatial economic inequalities under the framework of the dynamics of economic spaces in relation to the four global megatrends: globalization, knowledge-based economy, information society, and the service world. The international inequalities in East Asia, as well as inter-regional inequalities within Japan, Korea, and Thailand were analyzed. The variables related to the four megatrends, as a whole, have clearly explained the variations in international inequalities in East Asia, as well as the inter-regional inequalities within a nation. The individual impacts of the variables on spatial inequalities are, however, significantly different depending on the spatial scale of analysis and national characteristics. Overall, there has been a convergence trend of international per capita GNI (Gross National Income) in East Asian nations, while both divergent and convergent trends are evident at the regional scale within a nation. Two global oil crises in the 1970s and the East Asian financial crisis in the late 1990s resulted in the discontinuity of the general convergence trend, and have led to the increase of international and inter-regional inequalities in economic activities. This suggests that although the effect of the global crisis differs in each country, in general, the economies of peripheral countries and regions are more vulnerable during a global economic crisis.

• Communications of the Korean Mathematical Society
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• v.12 no.4
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• pp.985-998
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• 1997

For n random strips chosen so as to meet a fixed bounded convex set K of the plane we let $\nu$ be the number of intersection regions that meet K. We develop the integral formula for the mean value of $\nu$ and $\nu^2$ involving the area and the perimeter of K and the breadths of the strips. We get some geometric inequalities in way of studying integral geometry.

• Health Policy and Management
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• v.31 no.2
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• pp.188-196
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• 2021

Background: This study purposed to analyze the relationship between extinction risk regions and amenable mortality. Methods: This was a cross-sectional study based on the statistics of 2018 which was extracted from the 228 administrative districts in Korea. Cause of death statistics on each region in 2018 was used to produce the age-adjusted amenable mortality. Regional characteristics were measured by demographic factors, health behavior factors, socioeconomic factors, and medical resources factors. Multiple linear regression model was applied to test their relationship. Results: Results showed that extinction risk regions, crude divorce rates, national cancer screening rates, and independent rate of finance were significantly related to the amenable mortality. Conclusion: The study demonstrated differences in health status by the extinction risks of regions. This study suggests that the use of customized community care program can provide integrated services such as housing, health care or the use of information and communications technology which can make early diagnosis.

• Journal of applied mathematics & informatics
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• v.6 no.2
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• pp.631-638
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• 1999

Sensitive testing has been widely employed for many years in connection with the development and evaluation explosives detonation devices and propellants. Perhaps its earliest and possibly most important implementation was in biological studies of dosage mortality and response to drugs. Recently sensitivity experiments has been employed in the evaluation of new materials subject to stress in various environments and in delineanation of unstable combustion regions in chemical propulsion systems. This paper discussed a sta-tistical development of sensitivity testing.

• Bulletin of the Korean Mathematical Society
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• v.57 no.6
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• pp.1529-1539
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• 2020

The present work is aimed at presenting some characteristic properties of functions that map open unit disk onto a lune in the right half plane. Furthermore, we introduce subclasses of functions with boundary and radius rotations which are related to crescent regions. Some useful results, which include coefficient inequalities and some subordination properties associated with these subclasses are derived. Consequently, related problems concerning these classes are also studied.

• Health Policy and Management
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• v.22 no.1
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• pp.85-108
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• 2012

One of the ways to achieve the principle of equal access for equal needs, availability and geographical accessibility of health care resources regardless of resident sites is important. The purpose of this paper is to measure socioeconomic inequities in distribution of health care resources among regions in the Republic of Korea (hereafter Korea). Data were extracted from regional statistics of National Health Insurance, Community Health Survey, Korea Social Science Data Archive, and Korean Statistical Information Services at the same period of 2009. The dependent variables were the number of health workforce and health care facilities in each region. The proxy indicator of regional socioeconomic status was local tax per person. To identify whether inequalities among regions, we examined the concentration index(CI) and indirectly standardized CI by controlling each region's demographics and need factors. Total observations were 232 districts in nationwide, and we analyzed separately Seoul(25 districts) and non-Seoul areas(207 districts). The standardized CI values of health care resources were positive(favoring the rich region) across the nation in almost all kinds of resources. Especially the number of specialist, dentist, dental clinics, clinics, oriental medical clinics, pharmacists, and pharmacies were statistically significantly favoring the rich region. But the CI for the number of long-term care hospitals, public health centers were negative(favoring the poor region). The tendency of CI presenting positive values were increased in Seoul area. But in the case of non-Seoul, the CI indexes were nearly zero. The results suggest that except the Seoul area, little regional socioeconomic-related inequalities were observed in the distribution of health care resources in Korea.

• Health Policy and Management
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• v.33 no.2
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• pp.118-128
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• 2023

Background: Personal socio-economic abilities are crucial as it affects health inequalities. These multidimensional inequalities across the regions have been structured and fixed. This study aimed to analyze health vulnerabilities by regional cluster and identify regional health disparities of self-rated health, using nationally representative cross-sectional data. Methods: This study used personal and regional data. Data from the Community Health Survey 2021 were analyzed. K-means cluster analysis was applied to 250 si-gun-gu using administrative regional data. The clusters were based on three areas: physical environment, health-related behaviors and biological factors, and the psychosocial environment through the conceptual framework for action on the social determinants of health. And binary logistic regression analyses were conducted to examine the differences in self-rated health status by the regional clusters, controlling human biology, environment, lifestyle, and healthcare organization factors. Results: The most vulnerable group was group 3, the moderate vulnerable group was group 1, and the least vulnerable group was group 2. The group 2 was more likely to have high self-rated health status than the moderate vulnerable group (odds ratio [OR], 1.023; p<0.001). And the group 3 showed low self-rated health status than the moderate vulnerable group (OR, 0.775; p<0.001). However, the moderate vulnerable group had significantly higher self-rated health status than the most vulnerable group (group 2: OR, 1.023; p<0.001; group 3: OR, 0.775; p<0.001). Conclusion: These results demonstrate that community members' health status is influenced by regional determinants of health and individual levels. And these contribute to understanding the importance of specific and differentiated interventions like locally tailored support programs considering both individual and regional health determinants.

• Nutrition Research and Practice
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• v.14 no.6
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• pp.679-690
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• 2020

BACKGROUND/OBJECTIVES: Concerns about regional disparities in heathy eating and nutritional status among South Korean adults are increasing. This study aims to identify the magnitude of regional disparities in diet and nutritional status among Korean adults who completed the 2017 Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: The participants were a nationally representative sample of Korean adults aged 19 years and older from the 2017 KNHANES (n = 6,126). We employed the svy commands in STATA to accommodate the complex survey design. The relative concentration index (RCI), absolute concentration index (ACI) and index of disparity were used to measure regional nutritional inequalities. RESULTS: Overweight and obese adults were more prevalent among the poor than among the rich in urban areas (RCI = -0.041; P < 0.05), while overweight and obese adults were more prevalent among the rich than among the poor in rural areas of South Korea (RCI = 0.084; P < 0.05). Economic inequality in fruit and vegetable intake ≥ 500 g per day was greater in rural areas than in urban areas in both relative size (RCI = 0.228 vs. 0.091, difference in equality = 0.137; P < 0.05) and absolute size (ACI = 0.055 vs. 0.023, difference in equality = 0.032; P < 0.05). CONCLUSIONS: This study provides useful information identifying opposite directions in the relative concentration curves between urban and rural areas. Adult overweight/obesity was more prevalent among the poor in urban areas, while adult overweight/obesity was more prevalent among the rich in rural areas. Public health nutrition systems should be implemented to identify nutritional inequalities that should be targeted across regions in South Korea.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.97-107
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• 2021

Abnormal climate caused by climate change causes enormous social and economic damage. And such damage and its impact may vary depending on the location and regional characteristics of the region and the social and economic conditions of local residents. Therefore, it is necessary to continuously monitor whether there are indicators that are weaker than other regions among the detailed indicators that constitute the risk, exposure and vulnerability of climate change risk. In this study, the concept of climate change risk was used for heatwave to determine regional inequality of climate change risk. In other words, it was judged that inequality in climate change risk occurred in regions with high risk but high exposure and low vulnerability compared to other regions. As a result of the analysis, it was found that 13 local governments in Korea experienced regional inequality in climate change risk. In order to resolve regional inequality in climate change risks, the current status of regional inequality in climate change should be checked based on the analysis proposed in this study, there is a need for an evaluation and monitoring system that can provide appropriate feedback on areas where inequality has occurred. This continuous evaluation and monitoring-based feedback system is expected to be of great help in resolving regional inequality in climate change risks.