Byung Ok Kim

Inje University Paik Hospital, Sŏul, Seoul, South Korea

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Publications (31)37.55 Total impact

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    Journal of cardiovascular ultrasound 09/2014; 22(3):162-3.
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    ABSTRACT: Besides poor clinical outcomes, female gender has been known as a high-risk factor for bleeding complications. This study aimed to investigate the impact of gender on clinical outcomes and bleeding complications after transradial coronary intervention (TRI). The Korean TRI registry is a retrospective multicenter registry with 4,890 patients who underwent percutaneous coronary intervention in 2009 at 12 centers. To compare clinical outcomes and bleeding complications between the male and female groups, we performed a propensity score matching in patients who received TRI. A total of 1,194 patients (597 in each group) were studied. The primary outcome was 1-year major adverse cardiac events, including all-cause mortality, myocardial infarction, target vessel revascularization, and stroke. The secondary outcome was major bleeding (composite of bleeding requiring transfusion of ≥2 units of packed cells or bleeding that was fatal). The proportion of major adverse cardiac events was similar between the 2 groups (6.2% vs 4.7%, p = 0.308). The female group had a greater incidence of major bleeding (0.3% vs 3.2%, p <0.001). On multivariate analysis, female gender (odds ratio [OR] 7.748, 95% confidence interval [CI] 1.767 to 13.399), age ≥75 years (OR 5.824, 95% CI 2.085 to 16.274), and chronic kidney disease (OR 7.264, 95% CI 2.369 to 12.276) were independent predictors of major bleeding. In conclusion, the female gender had a tendency for more bleeding complications than male gender after TRI without difference in the clinical outcome.
    The American journal of cardiology 04/2014; · 3.58 Impact Factor
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    ABSTRACT: The aim of our study was to determine the impact of vascular access on in-hospital major bleeding (IHMB) in acute coronary syndrome (ACS). We analyzed 995 patients with non-ST elevation myocardial infarction and unstable angina at the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines (CRUSADE) moderate- to very high-bleeding risk scores in trans-radial intervention (TRI) retrospective registry from 16 centers in Korea. A total of 402 patients received TRI and 593 patients did trans-femoral intervention (TFI). The primary end-point was IHMB as defined in the CRUSADE. There were no significant differences in in-hospital and 1-yr mortality rates between two groups. However, TRI had lower incidences of IHMB and blood transfusion than TFI (6.0% vs 9.4%, P = 0.048; 4.5% vs 9.4%, P = 0.003). The patients suffered from IHMB had higher incidences of in-hospital and 1-yr mortality than those free from IHMB (3.1% vs 15.0%, P < 0.001; 7.2% vs 30.0%, P < 0.001). TRI was an independent negative predictor of IHMB (odds ratio, 0.305; 95% confidence interval, 0.109-0.851; P = 0.003). In conclusions, IHMB is still significantly correlated with in-hospital and 1-yr mortality. Our study suggests that compared to TFI, TRI could reduce IHMB in patients with ACS at moderate- to very high-bleeding risk.
    Journal of Korean medical science 09/2013; 28(9):1307-15. · 0.84 Impact Factor
  • An Sung Lee, Byung Ok Kim
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    ABSTRACT: In this study, for the purpose of improving the rotordynamic characteristics of a large power recovery train, PRT, motor-generator rotor fundamentally by design, firstly, a bearing improvement analysis is carried-out by retrofitting from plain partial journal bearings, originally applied for an operation at a rated speed of 1,800 rpm, to final tilting pad journal bearings. Results show that satisfying evenly key basic lubrication performances such as the minimum lift-off speed and maximum oil-film temperature, a careful design solution of 5-pad tilting pad journal bearings may effectively result in enhancing the direct stiffness of bearings by about two times at such a relatively low rated speed. Next, a detailed rotordynamic analysis is performed, applying both of the original plain partial and retrofitted tilting pad journal bearings, in order to confirm the effect of rotordynamic improvement after the suggested bearing retrofit. Results show that the rotor unbalance response vibrations with the tilting pad journal bearings are greatly reduced to as much as about 11% of those with the plain partial journal bearings. In addition, for the tilting pad journal bearings there is no critical speed up to the rated speed while for the plain partial journal bearings there is one critical speed close to the rated speed with some damping but not sufficiently enough.
    ASME Turbo Expo 2013: Turbine Technical Conference and Exposition; 06/2013
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    ABSTRACT: BACKGROUND: Augmentation index (AIx) and pulse pressure amplification (PPA, here the aortic/brachial pulse pressure ratio) are an age-related emerging risk factor for cardiovascular disease. However, it has not been clearly shown that AIx and PPA predict a high risk of coronary artery disease (CAD). OBJECTIVES: The aim of the study was to investigate the association between non-invasively measured aortic wave reflection (AWR) and PPA and CAD. METHODS: The study group consisted of 80 patients who were admitted to our institute for elective coronary angiography. We non-invasively measured augmentation pressure (AP), AIx, and PPA using radial applanation tonometry. RESULTS: When the extent of CAD was divided by no or minimal CAD, 1- or 2- and 3-vessel disease (VD), there was a significant association between the extent of CAD and AIx and PPA in patients aged <65 years, but not in patients aged ≥65 years. In multivariate regression analysis after controlling the traditional risk factors, the odds ratio of having 3VD was significant in patients aged <65 years: 2.15 (1.04-4.44; p=0.039) per 5% increase of AIx and 2.02 (1.15-3.55; p=0.015) per 0.05 increase of PPA, but not in patients aged ≥65 years. The severity of CAD expressed as a Gensini score showed a significant correlation with AP, AIx, and PPA in patients aged <65 years, but not in patients aged ≥65 years. CONCLUSION: Increasing of non-invasively measured AWR and PPA is related to the severity of CAD, particularly in younger patients up to 65 years of age.
    Journal of Cardiology 05/2013; · 2.30 Impact Factor
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    ABSTRACT: Primary cardiac lymphoma (PCL) is a rare disorder, but the incidence is increasing and its clinical manifestations are various. We report a case of PCL, which mimics an acute coronary and aortic syndrome. A 51 year-old female was presented with chest pain radiating to the back. Her initial electrocardiogram revealed T wave inversion in the leads of V 5-6, II, III and aVF. Additionally, cardiac troponin-T was slightly elevated. Chest radiography showed marked mediastinal widening. Computed tomography scan showed a huge pericardial mass. The histopathologic findings of the mass were compatible with diffuse large B cell lymphoma. She died of refractory ventricular tachycardia, probably, due to an extensive infiltration of PCL to the myocardium.
    Korean Circulation Journal 11/2012; 42(11):776-80.
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    ABSTRACT: BACKGROUND: There is paucity of data with regard to the clinical spectrum according to left ventricle (LV) morphological variation in stress-induced cardiomyopathy (SCMP) patients, and still there is controversy in terms of prognosis since some people believe that the published in-hospital mortality data of patients with SCMP are underestimated. Therefore, we sought to investigate the morphological features of LV and in-hospital outcome of patients with SCMP and explored predictors of short-term prognosis. METHODS: This was a multicenter, observational study of 208 SCMP patients. Morphological features of LV were determined by echocardiography and were divided into typical (apical) and atypical ballooning types, which were subcategorized into mid-LV ballooning and basal 'inverted' ballooning type. All-cause mortality of patients with SCMP during hospitalization was recorded. RESULTS: The apical ballooning type was most common (67.3%) in SCMP followed by the mid-LV ballooning type (28.3%), and the basal 'inverted' ballooning type (4.3%). There were no differences in stressor types and in-hospital mortality between patients with typical and atypical SCMP. Notably, all the in-hospital mortality of SCMP patients occurred in patients with physical stressors, where age, shock, and LV ejection fraction were the independent risk factors for predicting in-hospital mortality. CONCLUSIONS: SCMP patients showed diverse patterns of LV morphology, but there were no definite differences on clinical spectrum among SCMP patients presenting various LV morphological patterns. In terms of short-term prognosis, underlying physical conditions combined with old age, hemodynamic compromise, and low LV systolic function might be the most important factors in SCMP patients.
    International journal of cardiology 10/2012; · 6.18 Impact Factor
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    ABSTRACT: BACKGROUND: It is well known that cardiac rehabilitation (CR) including regular exercise training (ET) is cardioprotective with respect to clinical events in patients with acute myocardial infarction (AMI). However, it is not known whether the regular ET may affect coronary restenosis after percutaneous coronary intervention (PCI) with stenting in AMI. The aim of this study was to evaluate the effect of regular ET on a stented coronary segment and its association with inflammatory markers in AMI. METHODS: Consecutively 74 AMI patients who underwent PCI with implantation of a drug-eluting stent and 9month follow-up angiography were included. Thirty seven patients who received CR with ET were assigned to the ET group. Another 37 patients who did not participate in ET, of similar age to those of participants, were assigned to the control group. At 9months, angiographic restenosis measured as in-segment late luminal loss of the stented coronary artery was analyzed via quantitative coronary angiography using CAAS 5.9. RESULTS: There were no significant differences in baseline characteristics including age, sex, body mass index, smoking, DM, hypertension, lipid profile, use of statin, and complete blood cell between two groups. On 9month follow-up angiography, late luminal loss per stent was significantly smaller in the ET group compared to the control group (0.14±0.57 vs. 0.54±0.88mm, p=0.02). Maximal oxygen consumption (VO(2)max) significantly improved in the ET group after 9months (27.9±6.4 vs. 30.8±5.2mL/kg/min, p<0.001). Increment in high density lipoprotein-cholesterol (HDL-C) was significantly larger in the ET group at 9months (0.15±0.12 vs. 0.04±0.24mg/dL, p=0.03). CONCLUSION: Regular ET contributes to a significant reduction in late luminal loss in the stented coronary segment in AMI patients. This effect was associated with increased exercise capacity and increased HDL-C.
    International journal of cardiology 07/2012; · 6.18 Impact Factor
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    Chul Kim, Hee Eun Choi, Byung Ok Kim, Min Ho Lim
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    ABSTRACT: To compare the rate of restenosis between a cardiac rehabilitation (CR) group and a control group within three different generations of drug eluting stents (DES). Patients who received DES due to an acute coronary syndrome were included. They were divided into a CR group and a control group. The CR group received six to eight weeks of early cardiac rehabilitation program in a hospital setting, and sustained a self-exercise program for six months in a community. The control group was instructed to exercise by themselves after leaving the hospital. Nine months after the first onset of disease, we implemented a coronary angiography and compared the two groups. In addition, we divided the patients into three subgroups according to the generation of DES, and compared the rate of restenosis between the CR group and control group within these three subgroups. At 9 months, in-stent restenosis, measured as an in-segment late luminal loss (LLL) of the stented coronary area, was smaller in the CR group (n=52) 0.16±0.42 mm compared to the control group (n=51) 0.39±0.78 mm (p<0.05). A reduction of LLL in the CR group compared to the control group was consistent among the three different generations of DES. The CR program is strongly associated with a significant reduction in LLL in the stented coronary segments, regardless of the generation of DES.
    Annals of rehabilitation medicine. 04/2012; 36(2):254-61.
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    ABSTRACT: To evaluate the effects of power walking (PW) training on a treadmill in patients with coronary heart disease (CHD) and to compare the cardiovascular effects of PW with usual walking (UW). Patients were recruited as participants in phase 2 cardiac rehabilitation program after receiving percutaneous coronary intervention (PCI) due to acute coronary syndrome from our hospital. The participants were divided into the PW group (n=16) and UW group (n=18). All participants received graded exercise test (GXT) and significant difference in maximal oxygen consumption (VO(2Max)) was not observed between the groups. Aerobic exercise training on treadmill was given for 50 minutes per session, three times a week, for six weeks. Physiological and hematological parameters were tested before and 6 weeks after the cardiac rehabilitation program. Exercise duration, VO(2Max), heart rate, blood pressure, and rate pressure product were evaluated through graded exercise test. Hematological measurements included serum lipid profile, and high-sensitivity C reactive protein (hs-CRP). There were no significant differences in resting heart rate, maximal heart rate, resting systolic and diastolic blood pressures, lipid profile, hs-CRP, VO(2Max), and RPP between the PW group and UW group. However, after 6 weeks of the intervention, VO(2Max) in the PW group (36.03±5.69 ml/kg/min) was significantly higher than that in the UW group (29.73±5.63 ml/kg/min) (p<0.05). After six weeks of phase 2 cardiac rehabilitation program, the PW group showed significant improvement in VO(2Max) than the UW group. Thus, it will beneficial to recommend power walking in cardiac rehabilitation program.
    Annals of rehabilitation medicine. 02/2012; 36(1):133-40.
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    ABSTRACT: Acute total obstruction of the left main coronary artery (LMCA) is a serious emergency condition requiring prompt diagnosis and treatment. Unless properly treated, it will like-ly progress to cardiogenic shock and a high mortality rate. We report a case of acute LMCA total obstruction present-ing with atypical momentary electrocardiogram (ECG) changes including right bundle branch block with left axis deviation, and ST-segment elevation in aVR and aVL. We focus on the unusual ECG changes associated with LMCA obstruction which should be noted in order to ensure revas-cularization without delay, especially when this condition is accompanied by cardiogenic shock.
    Journal of the Korean Society of Emergency Medicine. 02/2012;
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    Byung Ok Kim, Kyung Ho Sun, An Sung Lee
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    ABSTRACT: This paper deals with the study on repair case of journal shaft and bearing damage in 25MW industrial gas turbine caused by sudden blackout, operation mistake, and logic abnormal, etc. When a serious accident such as journal and bearing damage in a gas turbine occurs, the domestic local companies having the gas turbine are dependent on manufacturer for all maintenance and repair schedule until now. This case study shows that the damaged gas turbine is normally re-operated itself in domestic by establishing repair schedule in a short period of time, repairing damage journal shaft and tilting pad bearings, and performing rotating test for a reliability check. This paper can be regarded as the important case study of emergency test run experience of the refurbished 25MW gas turbine rotor.
    Journal of Fluid Machinery. 01/2012; 15(6).
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    ABSTRACT: This study investigated the efficacy and the safety of the upstream glycoprotein (Gp) IIb/IIIa inhibitor (clotinab; ISU ABXIS, Seoul, Republic of Korea) under 600-mg clopidogrel pretreatment compared with provisional use in ST-elevation myocardial infarction (STEMI). A total of 786 STEMI patients were randomized to upstream use in the emergency room (ER) (n = 392) or provisional use during percutaneous coronary intervention (PCI) (n = 394). All patients were prescribed 600-mg clopidogrel in the ER. The primary endpoint was the 30-day incidence of composite events including death, nonfatal myocardial infarction, target vessel revascularization, and stroke. There was no significant difference in the events that occurred in 40 patients (10.2%) in the upstream arm and 55 patients (14.0%) in the provisional arm during the 30 days (odds ratio 0.70, 95% confidence interval 0.45-1.08). Major bleeding was higher in the upstream arm (1.5% vs. 0%, P = 0.02). However, there was a significant reduction in 30-day composite events in the upstream arm in the high-risk population (Killip class ≥II or GRACE score >140). The upstream use of clotinab under a 600-mg clopidogrel loading may not significantly reduce cardiac events following primary PCI but may improve the clinical outcome in high-risk patients.
    Circulation Journal 12/2011; 76(2):405-13. · 3.58 Impact Factor
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    ABSTRACT: The aim of this study was to compare the efficacy and safety of zotarolimus-eluting stents (ZES), sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). This study was a prospective, single-blind, multicentre, randomised trial. The primary endpoint was major adverse cardiac events (MACE) at 12 months post-procedure, defined as cardiac death, recurrent myocardial infarction (MI), or ischaemia-driven target lesion revascularisation (TLR). An angiographic substudy was performed at nine months among 348 patients. From October 2006 to April 2008, 611 patients with STEMI undergoing primary PCI were randomly assigned to treatment with ZES (n=205), SES (n=204), or PES (n=202). The cumulative incidence of MACE was 5.9% in the ZES group, 3.4% in the SES group and 5.7% in the PES group at 12-month follow-up (p=0.457). There was a trend towards a lower rate of ischaemia-driven TLR at 12- (p=0.092) and 18-month (p=0.080) follow-up in the SES group compared to the ZES and PES groups. No difference was observed in rates of cardiac death, recurrent MI and combined death and/or recurrent MI among three groups at 12- and 18-month follow-up. The rate of stent thrombosis was similar among the three groups (2.0% in each group, p=1.000). As compared with SES and PES, the use of ZES in patients with STEMI undergoing primary PCI, showed similar rates of MACE, cardiac death and recurrent MI at 12 and 18 months. There was a trend towards a higher rate of TLR with ZES or PES compared to SES.
    EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 09/2011; 7(8):936-43. · 3.17 Impact Factor
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    ABSTRACT: The aim of the study was to assess the relationship between non-invasively (NIA) and invasively assessed (IA) aortic pulsatile indices and the presence and severity of coronary artery disease (CAD). The study group consisted of 58 patients who were admitted to our institute for elective coronary angiography (CAG). We measured the aortic systolic, diastolic and mean blood pressure (BP) using non-invasive and invasive techniques. We assessed the pulsatile indices of the aortic pressure waveform (APW) including pulse pressure (PP), fractional PP (FPP, the ratio of PP to mean BP) and pulsatility index (PI, the ratio of PP to diastolic BP). The severity of CAD was assessed by Gensini score. IA aortic PP, FPP and PI were significantly higher in patients with CAD than without CAD, but NIA indices did not show significant differences between two groups. After multivariate stepwise adjustment, the odds ratio (OR) and confidence interval (CI) of having significant CAD was: PP per 10 mmHg, OR = 2.51 (95% CI 1.12-5.63); FPP per 0.1, OR = 3.30 (95% CI 1.25-8.72); and PI per 0.1, OR = 1.88 (95% CI 1.09-3.23). In linear regression analysis, IA aortic systolic BP (SBP), PP, FPP and PI were significantly correlated with Gensini score, but NIA indices were not correlated. The NIA aortic PP was lower than IA aortic PP (mean difference: 6.1 ± 15.8 mmHg). IA aortic PP, FPP and PI were related to the presence and severity of CAD, but NIA assessed indices of APW were not related. NIA aortic PP underestimated IA aortic PP.
    Blood pressure 03/2011; 20(5):309-16. · 1.26 Impact Factor
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    ABSTRACT: Aspiration thrombectomy (AT) during primary percutaneous coronary intervention (PCI) is an effective adjunctive therapy for ST-segment elevation myocardial infarction (STEMI). An elevated neutrophil count in STEMI is associated with microvascular dysfunction and adverse outcomes. We evaluated whether AT can improve microvascular dysfunction in patients with STEMI and an elevated neutrophil count. Seventy patients with STEMI undergoing primary PCI from August 2007 to February 2009 in our institution were classified by tertiles of neutrophil count on admission (<5,300/mm(3), 5,300-7,600/mm(3), and >7,600/mm(3)). The angiographic outcome was post-procedural thrombolysis in myocardial infarction (TIMI) flow grade. Microvascular dysfunction was assessed by TIMI myocardial perfusion (TMP) grade and ST-segment resolution on electrocardiography 90 minutes after PCI. The clinical outcome was major adverse cardiac event (MACE), defined as cardiac death, re-infarction, and target lesion revascularization at 9 months. There were no significant differences in the clinical characteristics and pre- and post-procedural TIMI flow grades between the neutrophil tertiles. As the neutrophil count increased, a lower tendency toward TMP grade 3 (83% vs. 52% vs. 54%, p=0.06) and more persistent residual ST-segment elevation (>4 mm: 13% vs. 26% vs. 58%, p=0.005) was observed. The 9-month MACE rate was similar between the groups. On subgroup analysis of AT patients (n=52) classified by neutrophil tertiles, the same tendency toward less frequent TMP grade 3 (77% vs. 56% vs. 47%, p=0.06) and persistent residual ST-segment elevation (>4 mm: 12% vs. 28% vs. 53%, p=0.05) was observed as neutrophil count increased. A higher neutrophil count at presentation in STEMI is associated with more severe microvascular dysfunction after primary PCI, which is not improved with AT.
    Korean Circulation Journal 02/2011; 41(2):68-75.
  • An Sung Lee, Byung Ok Kim
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    ABSTRACT: Turbomachinery such as turbines, pumps and compressors, which are installed in transportation systems such as warships, submarines and space vehicles, etc., often perform crucial missions and are exposed to potential dangerous impact environments such as base-transferred shock forces. To protect the machines from such excessive shock forces, one may need to accurately analyze transient responses of rotors earlier on in their design stages, considering the dynamics of mount designs to be applied with. In this study, utilizing the generalized FE transient response analysis method of a flexible rotor-bearing system with a mount system to base-transferred shock forces, constructions of the shock response and static deflection maps of turbine rotor-bearing and mount system are devised, introducing the mount mass, resilient support stiffness and damping ratios to the counterpart rotor mass, bearing stiffness and damping and the mount system natural frequency. For the given turbine rotor system design a best available mount system design, composed of a mount plate and resilient support, can be readily selected from the constructed maps to meet the rotor’s shock response and mount’s static design limits. The shock response maps also show that for the same shock the FE flexible rotor model used herein yield a more compact light-weighed mount system design than the conventional simple rigid rotor model. Therefore, the shock response map approach in conjunction with the more complicated FE flexible rotor transient response analysis method is justified.
    ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition; 01/2011
  • American Journal of Cardiology - AMER J CARDIOL. 01/2011; 107(8).
  • American Journal of Cardiology - AMER J CARDIOL. 01/2011; 107(8).
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    ABSTRACT: Primary cardiac angiosarcoma is a very rare disease with a poor prognosis. We report a case of a patient with a primary cardiac angiosarcoma who presented with cardiac tamponade; the angiosarcoma was successfully resected surgically.
    Korean Circulation Journal 02/2010; 40(2):86-9.

Publication Stats

91 Citations
37.55 Total Impact Points

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Institutions

  • 2010–2014
    • Inje University Paik Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2012–2013
    • Korea Advanced Institute of Science and Technology
      Sŏul, Seoul, South Korea
  • 2005–2013
    • Korea Institute of Machinery and Materials
      Sŏul, Seoul, South Korea
  • 2011
    • Gachon University
      Sŏngnam, Gyeonggi Province, South Korea
  • 2008
    • Inje University
      Kŭmhae, South Gyeongsang, South Korea