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김철현 ( Chul Hyun Kim ),이영익 ( Young Ik Lee ),김윤만 ( Yoon Man Kim ),조인호 ( In Ho Cho ),제임스전 ( James Jeon ),김지연 ( Ji Yeon Kim ),박재현 ( Jae Hyun Park ),김혜진 ( Hea Jin Kim ),신경아 ( Kyung A Shin ),이승주 ( Seong Ju 한국운동영양학회 2004 Physical Activity and Nutrition (Phys Act Nutr) Vol.8 No.3
The α-actinin is an actin-binding protein belonging to the spectrin protein superfamily. a-actinin-3(ACTN-3) expression is limited to skeletal muscle, especially Type Ⅱ muscle fiber. This gene has homozygosity for a premature stop codon resulting in a-actinin-3 deficiency. The deficiency in the type Ⅱ muscle is able to be compensated by a-actinin-2(ACTN-2). While that deficiency does not induce a disease phenotype, the ACTN-3 is highly conserved in evolutionary terms because of its functions independent of the ACTN2. Researchers have suggested that this trait is related to muscle function at the extremes of power performance. Therefore, we compared the relative frequencies of the ACTN-3 R577X polymorphism between anaerobic power athletes and control group. For this study, we recruited 158 sprint or power elite athletes and 414 healthy adults. The results of the current study showed significant differences in the genotype frequencies such that elite anaerobic power athletes have 4% higher of the RR genotype and 9% lower of the XX genotype than the healthy adults. With respect to the allele frequencies, the athletic group had significantly higher R allele frequency and significantly lower X allele frequency than the control group. In summary, these results suggest that the ACTN-3 R577X genotype may represent a genetic marker for anaerobic power performance.
김철현(Kim Chul Hyun),김혜진(Kim Hyeoi Jin) 한국체육측정평가학회 2014 한국체육측정평가학회지 Vol.16 No.1
이 연구는 한국 성인의 비만을 평가하기 위해 체지방률의 기준치와 동등한 체질량지수의 분별점을 확인하고, 체질량 지수에 대한 유용성을 판단하고자 하였다. 이를 위해 한국성인 929명(남성 364명, 여성 565명, 18~64세)을 대상으로 신체구성의 준거방법인 DXA를 이용하여 체지방률을 구하고, 신장과 체중을 이용하여 체질량지수(BMI)를 산출하였다. 체질량지수와 체지방률에 대한 관계를 분석하기 위해 상관분석과 회귀분석을 실시하였으며, 체질량지수 분별치의 설정 을 위해 ROC 곡선과 일치도 검사를 실시하였다. 연구결과, 체질량지수는 체지방률에 대하여 남녀 모두에서 높은 정적 상관관계를 나타내었다(남자 r=0.816, %fat=1.437×BMI-14.397, p<0.01; 여자: r=0.751, %fat=1.609×BMI-4.567, p<.01). 그리고 ROC 곡선을 이용하여 분석한 체질량지수의 과체중은 남자는 23kg.m-2, 여자는 22kg.m-2를 나타내 었고, 비만 기준은 남자와 여자 모두 체질량지수 25kg.m-2인 것으로 분석되었다. 한편, 기존의 국제 체질량지수 분별 치와 아시아 권장 체질량지수 분별치를 체지방률 진단법에 대한 일치도로 분석한 결과, 남자는 63.2%, 여자는 72.6% 이고, Kappa 계수는 남자가 0.440(p<.001) 여자가 0.570(p<.001)로 나타났다. 이상의 결과를 종합해 보면 우리나라 성인 BMI의 비만진단 기준은 아시아태평양 권장 BMI 비만진단기준인 23kg.m-2과 25kg.m-2가 적합하다. 그러나 BMI가 신체구성성분(체지방)이 아닌 신체계측지수인 것을 고려할 때 향후 현장에서 체지방을 쉽고 정확하게 측정하는 방안이 필요할 것으로 사료된다. The World Health Organization consensus proposed ethnically specific criteria of body mass index(BMI) for abnormally accumulated fatness(obesity). However, the nationwide definition of BMI is still debated in Korea. Therefore, this study aimed to determine the cut-off points of body mass index for overweight and obesity in Korean adults by the ROC curve analysis. For this study, we recruited 929 Korea adults(364 men, 565 women) aged 18 to 64. Body compositions including body fat, fat-free mass, and percentage body fat were measured by DXA and body mass index was also assessed by weight and height. The correlation, regression analysis, ROC curve, agreements and Kappa test were performed for the relationships between %fat and BMI, determination of BMI cutoff points for overweight and obesity and final confirmation of usefulness of BMI for obesity diagnosis. As results, BMI and percentage body fat were closely associated in both men(r=0.861, p<.01) and women(r=0.751, p<.01) with the regression equation in %fat=1.437×BMI-14.397 for men and %fat=1.609×BMI-4.567(p<.01). According to the ROC curve, 23kg.m-2 and 23kg.m-2 of BMI in men and women had highest sensitivity and specificity in related to optimal sensitivity and specificity in relation with obesity of body fat. Overall percentage agreements between %fat-based obesity diagnosis and BMI-based obesity diagnosis were located into 0.368~726. In conclusion, the profit cutoffs of BMI for obesity for Korean adults were 23kg.m-2 for overwieght and 25kg.m-2 for obeisty in both men and women in this study. However, there were limitations and needs for using BMI such as percentage body fat. Further studies were needed to develop usuful and practical percentage body fat for obesity diagnosis.
운동유발성 고혈압 주자의 울트라 마라톤 달리기가 전구염증과 항염증 사이토카인 및 혈관내피세포 기능인자에 미치는 영향
김철현 ( Chul-hyun Kim ),강덕호 ( Duk-ho Kang ),김영주 ( Young-joo Kim ) 대한스포츠의학회 2016 대한스포츠의학회지 Vol.34 No.2
Running for a long distance in runners with exercise-induced hypertension (EIH) increases high blood pressure (BP) which causes myocardial burden, inducing elevation of cardiac markers. It is assumed to be associated with endothelial dysfunction, but has not been studied so far. The purpose of this study is to exam the responses of anti-inflammatory, inflammatory, and endothelial regulation factors to 100 km ultra-marathon of athletes who have EIH. For this study, we obtain and analysis interleukin-6, tumor necrosis factor-α, interleukin-10 (IL-10), monocyte chemoattractant protein-1, creatine kinase and nitric oxide (NO) from 100 km ultra-marathoners before and right after the 100 km race. There were 40 volunteers who had ever won the 100 km marathon race before more than one time. They had the graded exercise test with measurement of BP for assessing EIH. Among them, eight athletes were categorized to normal control group (NCG) and 10 athletes were assessed by EIH group (EIHG). The graded exercise test with treadmill was performed for the maximal strenuous exercise and BP. EIH was diagnosed as <140/90 mm Hg in normal and ≥210 mm Hg in maximal exercise. Marathoners including EIHG (n=10) and NCG (n=8) participated in the race and blood extracted from them before the race and right after the race. As results, EIHG had lower IL-10 than NCG during resting states and after the 100 km race EIHG had significantly lower NO concentration than NCG. Therefore, the NO in the endothelial is inhibited during strenuous endurance exercise, resulting in vasoconstriction with increasing the BP.
엘리트 운동선수에서 부위별 다주파수 생체 전기 임피던스법(SMF-BIA)에 의한 체지방 추정의 유효성
김철현(Chul Hyun Kim) 한국사회체육학회 2008 한국사회체육학회지 Vol.0 No.34
The purpose of this study was to exam the accuracy and availability of SMF-BIA to predict percent body fat(%fat) of elite athletes in Korea. 183 elite athletes (107 male, 76 female) participated on the present study. Interview was administered for finding disease and any change of body composition, and than tests were proceeded including hieght, weight, SMF-BIA, and DEXA. The data of predicted %fat by SMF-BIA and measured %fat by DEXA were analyzed by the simple linear regression analysis, T-test, and Bland-Altman methods. The results showed that the correlation coefficient between predicted %fat and measured %fat was r=0.757 and r=0.667 in male and female respectively. Also, the slopes for the line of identity and y-intercepts were significantly different from the zero or one in both male and female. However, the total errors were 2.3%fat in male and 2.6%fat, which were evaluated as `very good`. In the Bland-Altman plot, the residuals in male had a negatively correlation with the mean of %fat from SMF-BIA and DEXA, but not in female. The results suggested that the regression equation of %fat by SMF-BIA was low in accuracy. Especially, use of SMF-BIA in male athletes should be great careful because of existence of systemic errors.
김철현 ( Chul-hyun Kim ),이동수 ( Dong-su Lee ),이민태 ( Min-tae Lee ),김병기 ( Byung-ki Kim ) 한국정보처리학회 2007 한국정보처리학회 학술대회논문집 Vol.14 No.1
본 논문에서는 Model Driven Architecture를 다양한 모바일 플랫폼에서 적용하는 방안에 대해 설명한다. 모바일 플랫폼은 Symbian OS, Microsoft Windows CE 등 다양한 종류가 있으며, 이들의 어플리케이션을 재사용하기 위해서는 각 플랫폼에 맞는 언어로 다시 개발해야 한다. MDA는 이러한 이기종의 플랫폼에 적용할 수 있는 가장 효율적인 아키텍처이다. PIM 모델을 작성하고 변환규칙을 적용한 자동화 도구로써 PSM 모델과 소스코드까지 자동으로 생성이 가능하기 때문에 높은 개발 생산성과 이식성, 상호운용성을 제공할 수 있다.
디지털 시네마 영상의 최적 압축을 위한 H.264/AVC와 JPEG-2000 비교 연구
김철현(Kim Chul-Hyun),강남오(Knag Nam-Oh),김용환(Kim Yong-Hwan),정수연(Jung Soo-Yeun),임상희(Lim Sang-Hee),백준기(Paik Joon-Ki) 한국방송·미디어공학회 2006 한국방송공학회 학술발표대회 논문집 Vol.2006 No.-
현재 디지털 시네마의 압축 표준으로는 DCI(Digital Cinema Initiatives)에 의해 정지 영상 압축의 국제 표준인 JPEG-2000이 선정되어 있다. 하지만 영상 압축에 있어 또 하나의 국제 표준인 H.264/AVC는 현재까지 동영상 압축에 있어 과거 어떤 동영상 압축 코덱보다 큰 효율을 달성해왔다. 본 논문에서는 이 두 가지 압축 방법을 사용하여 디지털 시네마 압축에서 요구하는 시각적 무손실 압축을 연구하였다. 즉 실험 영상에 다양한 파라메터 값으로 JPEG-2000과 H.264/AVC 압축을 수행 하였고 산출된 결과를 시각적 무손실 압축의 환경 조건하에서 제시하였다. JPEG-2000의 경우 RATE 0.02, 0.03 이전의 PSNR 변화값이 낮은 편이었으며, DCI 규격에도 만족시키는 결과를 보여주었다. H.264의 경우 압축 성능에 있어서 JPEG-2000보다 다소 우월한 결과를 보여주었다. 계층적 코딩을 통해 매체간 높은 호환성을 보장하는 H.264/AVC의 장점은 디지털 시네마의 배포에 적용 가능함을 함께 고려할 때 JPEG-2000과 함께 디지털 시네마를 위한 압축 표준으로 고려해 볼 만 하다.