• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.117-124
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• 2011

Valve springs with non-circular cross-section are widely used in automotive engines. Because of the reduced height, the oval cross-section provides some merits in its install height and stress distribution. This paper introduces a new method to generate optimal shape of the non-circular cross-section. For given width and height, arbitrary shape of the cross-section are described using the Hermite spline curves. Cross-section area and maximum stress level are chosen as performance indices, and nonlinear optimization problems are formulated with inequality constraints. Compared to a production spring wire, cross-section area can be reduced about 2.4 [%] without increasing maximum stress level. In addition, the other approach gives an optimum cross-section which reduces maximum stress level of 2.0 [%] without increasing cross-section area.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.201-204
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• 2016

This study aimed to quantify associations of the human development inequality (HDI) index with incidence, mortality, and mortality to incidence ratios for eight common cancers among different countries. In this ecological study, data about incidence and mortality rates of cancers was obtained from the Global Cancer Project for 169 countries. HDI indices for the same countries was obtained from the United Nations Development Program (UNDP) database. The concentration index was defined as the covariance between cumulative percentage of cancer indicators (incidence, mortality and mortality to incidence ratio) and the cumulative percentage of economic indicators (country economic rank). Results indicated that incidences of cancers of liver, cervix and esophagus were mainly concentrated in countries with a low HDI index while cancers of lung, breast, colorectum, prostate and stomach were concentrated mainly in countries with a high HDI index. The same pattern was observed for mortality from cancer except for prostate cancer that was more concentrated in countries with a low HDI index. Higher MIRs for all cancers were more concentrated in countries with a low HDI index. It was concluded that patterns of cancer occurrence correlate with care disparities at the country level.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.623-627
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• 2014

Background: Esophagus cancer (EC) is among the five most common cancers in both sexes in Iran, with an incidence rate well above world average. Social rank (SR) of individuals and regions are well-known independent predictors of EC incidence. The aim of current study was to assess gender and social disparities in EC incidence across Iran's provinces through 2003-2009. Materials and Methods: Data on distribution of population at province level were obtained from the Statistical Centre of Iran. Age-standardized incidence rates of EC were gathered from the National Cancer Registry. The Human Development Index (HDI) was used to assess the province social rank. Rate ratios and Kunst and Mackenbach relative indices of inequality ($RII_{KM}$) were used to assess gender and social inequalities, respectively. Annual percentage change (APC) was calculated using joinpoint regression. Results: EC incidence rate increased 4.6% and 6.5% per year among females and males, respectively. There were no gender disparities in EC incidence over the study period. There were substantial social disparities in favor of better-off provinces in Iran. These social disparities were generally the same between males and females and were stable over the study period. Conclusions: The results showed an inverse association between the provinces' social rank and EC incidence rate in Iran. In addition, I found that, in contrast with international trends, women are at the same risk of EC as men in Iran. Further investigations are needed to explain these disparities in EC incidence across the provinces.

• Health Policy and Management
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• v.29 no.3
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• pp.288-302
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• 2019

Background: The one-person households (OPH) are rapidly increasing and vulnerable to socioeconomic and health problems. Because it is predicted to be inequitable to health care utilization, we would like to find out about the equity of health care utilization of the OPH by comparison with the multi-person households (MPH). Methods: This study followed the theoretical framework of Wagstaff and van Doorslaer (2000), O'Donnell and his colleagues (2008), where the horizontal inequity index is the difference between the concentration indices of actual health care utilization and health care needs. This study employed the 9th Korea Health Panel survey, and a total of 10,807 cases were analyzed. Health care needs were measured by age, sex, subjective health status, chronic disease count, Charlson's Comorbidity Index, limitation of activities, and disability. Results: Compared with the MPH, there were pro-poor inequities in hospitalization, emergency utilization, hospitalization out-of-pocket payments, and pro-rich inequities in outpatient out-of-pocket payments for the OPH. The decomposition of the concentration index revealed that chronic disease count made the largest contribution to socioeconomic inequality in outpatient utilization. Age, health insurance, economic activities, and subjective health status also proved more important contributors to inequality. The variables contributing to the hospitalization and emergency utilization inequity were age, education, Charlson's Comorbidity Index, marital status, and income. Conclusion: Because the OPH was more vulnerable to health problems than the MPH and there were pro-poor inequities in medical utilization, hospitalization, and emergency costs, it is necessary to develop a policy that can correct and improve the portion of high contribution to medical utilization of the OPH.

• Journal of Preventive Medicine and Public Health
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• v.46 no.5
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• pp.237-248
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• 2013

Objectives: The purpose of this study is to examine and explain the extent of income-related inequity in health care utilization and expenditures to compare the extent in 2005 and 2010 in Korea. Methods: We employed the concentration indices and the horizontal inequity index proposed by Wagstaff and van Doorslaer based on one- and two-part models. This study was conducted using data from the 2005 and 2010 Korean National Health and Nutrition Examination Survey. We examined health care utilization and expenditures for different types of health care providers, including health centers, physician clinics, hospitals, general hospitals, dental care, and licensed traditional medical practitioners. Results: The results show the equitable distribution of overall health care utilization with pro-poor tendencies and modest pro-rich inequity in the amount of medical expenditures in 2010. For the decomposition analysis, non-need variables such as income, education, private insurance, and occupational status have contributed considerably to pro-rich inequality in health care over the period between 2005 and 2010. Conclusions: We found that health care utilization in Korea in 2010 was fairly equitable, but the poor still have some barriers to accessing primary care and continuing to receive medical care.

• KDI Journal of Economic Policy
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• v.26 no.2
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• pp.105-141
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• 2004

The success of fiscal decentralization depends on an effective intergovernmental transfer system. This paper focuses on the Local Share Tax(LST), the primary intergovernmental fiscal transfer in Korea. The LST, by law, aims to mitigate horizontal fiscal imbalance among the local governments. As an attempt to test the fiscal equity of the LST empirically, net fiscal benefits of each county are calculated based on a simple model. While the LST contributes to horizontal fiscal measured traditional inequality indices, a geographical pattern of net fiscal benefits is observed. From these findings, the role of LST on fiscal equity needs to be carefully re-examined.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2189-2196
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• 2016

This paper proposes a new finite control set-model predictive control (FCS-MPC) method for induction motors. In the method, the reference state that satisfies the given torque and rotor flux requirements is derived. Cost indices for the FCS-MPC are defined using the state tracking error, and a linear matrix inequality is formulated to obtain a proper weighting matrix for the state tracking error. The on-line procedure of the proposed FCS-MPC comprises of two steps: select the output voltage vector of the two level inverter minimizing the cost index and compute the optimal modulation factor of the minimizing output voltage vector in order to reduce the state tracking error and torque ripple. The steady state tracking error is removed by using an integrator to adjust the reference state. The simulation and experimental results demonstrated that the proposed FCS-MPC shows good torque, rotor flux control performances at different rotating speeds.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.45-52
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• 2004

There are many cities installing ITS(Intelligent Transportation Systems) and running TMC(Trafnc Management Center) to improve mobility and safety of roadway transportation by providing roadway information to drivers. There are many devices in ITS which collect real-time traffic data. We can obtain many valuable traffic data from the devices. But it's impossible to avoid missing traffic data for many reasons such as roadway condition, adversary weather, communication shutdown and problems of the devices itself. We couldn't do any secondary process such as travel time forecasting and other transportation related research due to the missing data. If we use the traffic data to produce AADT and DHV, essential data in roadway planning and design, We might get skewed data that could make big loss. Therefore, He study have explored some imputation techniques such as heuristic methods, regression model, EM algorithm and time-series analysis for the missing traffic volume data using some evaluating indices such as MAPE, RMSE, and Inequality coefficient. We could get the best result from time-series model generating 5.0$\%$, 0.03 and 110 as MAPE, Inequality coefficient and RMSE, respectively. Other techniques produce a little different results, but the results were very encouraging.

• Journal of Preventive Medicine and Public Health
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• v.51 no.2
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• pp.83-91
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• 2018

Objectives: One of the main objectives of the Targeted Subsidies Law (TSL) in Iran was to improve equity in healthcare financing. This study aimed at measuring the effects of the TSL, which was implemented in Iran in 2010, on equity in healthcare financing. Methods: Segmented regression analysis was applied to assess the effects of TSL implementation on the Gini and Kakwani indices of outcome variables in Iranian households. Data for the years 1977-2014 were retrieved from formal databases. Changes in the levels and trends of the outcome variables before and after TSL implementation were assessed using Stata version 13. Results: In the 33 years before the implementation of the TSL, the Gini index decreased from 0.401 to 0.381. The Gini index and its intercept significantly decreased to 0.362 (p<0.001) 5 years after the implementation of the TSL. There was no statistically significant change in the gross domestic product or inflation rate after TSL implementation. The Kakwani index significantly increased from -0.020 to 0.007 (p<0.001) before the implementation of the TSL, while we observed no statistically significant change (p=0.81) in the Kakwani index after TSL implementation. Conclusions: The TSL reform, which was introduced as part of an economic development plan in Iran in 2010, led to a significant reduction in households' income inequality. However, the TSL did not significantly affect equity in healthcare financing. Hence, while measuring the long-term impact of TSL is paramount, healthcare decision-makers need to consider the efficacy of the TSL in order to develop plans for achieving the desired equity in healthcare financing.

• The Korean Journal of Health Service Management
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• v.6 no.4
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• pp.13-25
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• 2012

There is growing evidence that substance use such as tobacco or alcohol consumption influences health disparity among adolescents. Previous research papers have shown an inconsistency in the relationship between socio-economic status (SES) and substance use in adolescents. However, little is known about socio-economic differences in unhealthy behaviors among Korean adolescents. The purpose of the present study is to explore associations between SES and substance use in Korean adolescents. The analysis was performed using data from the 2009 Korean Youth Risk Behavior Web-based Survey (YRBS), which included a nationally representative sample of middle and high school students. Drinking/heavy drinking and smoking/daily smoking behavior indices were used for dependent variables, and perceived economic status, family affluence score, parents' education were used for independent variables. Chi-square test were used to compare tobacco and alcohol consumption among 3 SES groups. Logistic regression models were used to identify statistically significant socio-economic factors after adjusting other covariates. Higher perceived economic status and higher family affluence were associated with higher rates of smoking, daily smoking, drinking, and heavy drinking, while lower level of parents' education was related to higher use of tobacco and alcohol. Socio-economic status significantly influences health behaviors in adolescents, and it may consequently affect health disparity in their adulthood. Therefore, there is a need of continuous monitoring and follow-up research of health disparity among adolescents.