소아 비알코올성 지방간의 최신 지견

이경훈,Lee, Kyung-Hun 대한소아소화기영양학회 2009 Pediatric gastroenterology, hepatology & nutrition Vol.12 No.suppl1

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of pediatric liver disease. Similar to NAFLD in adults, NAFLD in children is associated with obesity and insulin resistance and requires liver histology for diagnosis and staging. However, significant histological differences exist between adult and pediatric NAFLD. The rise in childhood obesity has been accompanied by an increase in pediatric NAFLD. Age, gender and race/ethnicity are significant determinants of risk, and sex hormones, insulin sensitivity and adipocytokines are implicated in the pathogenesis of pediatric NAFLD. There is no consensus for treatment of NAFLD, however, data suggest that diet, exercise and some pharmacological therapies may be of benefit. To evaluate and effectively treat pediatric NAFLD, the pathophysiology and natural history of the disease should be clarified and non-invasive methods for screening, diagnosis, and longitudinal assessment developed.

국내 운용 UHF-윈드프로파일러 레이더의 원시 스펙트럼 분석

이경훈,권병혁,김유진,이건명,Lee, Kyung-Hun,Kwon, Byung-Hyuk,Kim, Yu-Jin,Lee, Geon-Myeong 한국전자통신학회 2022 한국전자통신학회 논문지 Vol.17 No.5

In this paper raw spectrum data were analyzed to suggest the moving forward of performance evaluation and quality control of wind profilers of four manufacturers operating in South Korea. For the analysis, the profile of the spectrum averaged by season and the profile of four statistical values (minimum, average, median, and maximum) calculated by Power Spectrum Density (PSD) were used. The quality of spectrum data was the best for LAP-3000, followed by YKJ3, PCL-1300, and CLC-11-H. In Cheorwon and Chupungnyeong, where PCL-1300 was installed, the variability of the spectrum due to ground clutter and non-meteorological signals was large, so ground clutter removal and signal processing such as moving average and multi-peak were required. In Gunsan and Paju, where CLC-11-H was installed, DC (Direct Current) bias and propagation folding were found, so it is necessary to remove the DC bias and limit the effective altitude for observation.

온도를 변수로 갖는 단기부하예측에서의 TAR(Threshold Autoregressive) 모델 도입

이경훈(Kyung-Hun Lee),이윤호(Yunho Lee),김진오(Jin-O Kim) 대한전기학회 2000 대한전기학회 학술대회 논문집 Vol.2000 No.11

다입자유한요소법을 이용한 Al분말 압축공정에서 입자의 거동과 변형에 관한 연구

이경훈(Kyung Hun Lee),이정민(Jung Min Lee),김병민(Byung Min Kim) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.4

본 논문에서는 알루미늄 분말의 치밀화 거동을 분석하기 위하여 다입자유한요소모델을 이용한 분말압축 해석방법을 제시하였다. 다입자유한요소모델을 이용하여 압축공정 동안 압축속도와 입자크기가 입자의 변형거동과 분말의 치밀화에 미치는 영향을 조사하였다. 유한요소해석결과는 평균입도 20, 3㎛의 알루미늄 분말에 대한 일축압축시험을 통해 검증되었다. 압축시험은 만능재료시험기(MTS)를 이용하였으며 해석과 동일하게 5와 15, 30, 60㎜/min압축속도에 대해 수행되었다. 입자직경이 감소할수록 입자간 마찰이 증가하기 때문에 압출하중은 증가하였다. 압축속도가 감소할수록 증가된 입자의 회전모멘트는 입자간의 이동과 분말의 치밀화에 기여하여 최종 분말의 상대밀도를 증가시킨다. This paper describes multiparticle finite element model (MPFEM)-based powder compaction simulations performed to demonstrate the densification of compacted aluminum powders. A 2D MPFEM was used to explore the densification of a collection of aluminum particles with different average particle sizes under various ram speeds. Individual particles are discretized using a finite element mesh for a detailed description of contact mechanics. Porous aluminum powders with average particle sizes of 20 ㎛ and 3 ㎛ were compressed uniaxially at ram speeds of 5, 15, 30, and 60 ㎜/min by using an MTS servo-hydraulic tester. The slow ram speed was of great advantage to powder densification in low compaction force due to sufficient particle rearrangement. Owing to a decrease in the average particle size of aluminum, the compaction force increased.

단락제어에 따른 입향상진 피복아크 용접 특성에 관한 연구

이경훈(Kyung-Hun Lee),유회수(Hoi-Soo Ryoo),현승균(Soong-Keun Hyun) 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.5

SMAW can be used all position mode and anywhere. The weldabiltiy of SMAW depends on the skill of the welder. Especially, the welding of horizontal and vertical-up position is very difficult for beginners to weld. The E4316 (low hydrogen type) electrode is more difficult to weld than other electrodes due to frequent sticking at low current welding. In this study, it is considered that the weldability of E4316 was improved in the case of short-circuit control at vertical-up welding. The characteristics was evaluated by shortcircuit control and compare with flat welding. The SMA welding power source with short-circuit control function was used. The waveform measurement was performed to analyze the characteristics of short- circuit control. As a result, the difficulty of vertical-up welding at low current is due to the low frequency of short-circuit and the long short-circuit period. The short-circuit control is increase weldability of vertical- up by suppressed long short-circuit. So, it is possible to easily weld vertical-up welding by using a short-circuit-controlled SMA welding power source.

자동굴절검사와 자각적 굴절검사의 비교분석 : 사진굴절검사기(VS100)를 중심으로

이경훈(Kyung-Hun Lee),심현석(Hyun-Suk Shim) 한국안광학회 2018 한국안광학회지 Vol.23 No.1

Purpose: This study was conducted for comparition the refractive error measured by auto-refraction and subjective refraction. Methods: 100 adults (200 eyes, mean age 22.04±3.14 years) included in this study. Refractive error was measured using by a Photorefractor (VS100), an open-view autorefractor (Nvision k-5001), and a closed autorefractor (ARK-1a). The measured values were converted into power vector components (M, J0, J45) and compared with subjective refraction. Results: The mean difference between subjective refraction and VS100 was M = -0.08±0.67 D, J0= -0.02±0.28 D, J45 = 0.01±0.23 D, and there was no significant difference in all components (p>0.05). The accuracy coefficients were M= 1.313, J0= 0.564, J45= 0.454. The mean difference between the subjective refraction and ARK-1a was M = 0.49±0.84 D, J0 = -0.05±0.19 D, J45 = 0.01±0.14 D, and there was a significant difference between the M and J0 components (p<0.05). However J45 components were not significantly different (p>0.05). The accuracy coefficients were M = 1.664, J0 = 0.372, J45 = 0.292. The mean difference between the subjective refraction and the Nvision K-5001 was M = 0.16±0.63 D, J0 = -0.09±0.30 D, J45 = 0.01±0.18 D, with a significant difference between M and J0 components (p<0.05), but there was no significant difference in J45 (p>0.05). The accuracy coefficients were M = 1.250, J0 = 0.603, J45 = 0.364. Conclusions: As a result of comparing the refractive error of the autorefractor, the refractive power of the photorefractor was measured in the positive direction, but this is considered to be less influenced by the accommodation, and the difference is considered to be small in term of clinical view. The sensitivity of VS100 was 87.7% and the specificity was 75.9%, which was useful for measuring refractive error and correlated with subjective refraction. Photorefractor can be used as a preliminary examinations for subjective refraction because they can open the binocular and measure the refraction error without a large mistake in a short time.

카지노 종사원의 감정노동과 직무만족 간 영향관계 연구 -강원랜드 비정규직을 중심으로-

이경훈 ( Kyung Hun Lee ),김기동 ( Gi Dong Kim ),이희철 ( Hee Chul Lee ) 한국호텔리조트학회(구 한국호텔리조트카지노산학학회) 2013 호텔리조트연구 Vol.12 No.2

본 연구는 그동안 감정노동에 관한 연구가 실무현장 중심의 직군에 한정되어 연구가 이루어지는 한계를 극복하고, 종사자가 지각하는 감정노동을 조직적인 차원에서 접근하고자 하는데 목적이 있다. 또한 조직성과 지표인 직무만족과의 영향관계를 파악하여 정규직대상자의 감정노동을 관리할 수 있는 정책방안을 마련하고자 하였다. 이러한 연구 목적을 달성하기 위하여 감정노동에 대한 선행연구를 고찰하였고, 강원도 정선소재 K카지노에 근무하는 3년차 비정규직 카지노 종사원을 대상으로 감정노동에 대한 개인의 인식정도를 설문지를 통해 파악하였는데, 분석 결과를 요약하면 다음과 같다. This study identifies mutual relationships on how the emotional hardship element influences the job satisfaction of, so-called non-regular worker and if that satisfied worker acts with client-oriented attitude to have a positive change on the job performance of oneself. By identifying this, the study wants to suggest the human resource strategy for the development of Kangwon Land. The outcome of the verification of hypothesis shows the importance of the relation of labor hardship and job satisfaction that is aiming the non-regular worker since it has hired. In other words, the importance of labor hardship is expanding since a company is not only benefitted by the clients of direct benefit but also benefitted with positive results by the satisfaction of its non-regular worker, the workers.

탄소나노튜브와 나노클레이를 포함하는 폴리스티렌 및 스티렌계 공중합체 나노복합재료의 물성에 관한 연구

이경훈 ( Kyung Hoon Lee ),김영두 ( Young Doo Kim ),이민호 ( Min Ho Lee ),민병훈 ( Byong Hun Min ),김정호 ( Jeong Ho Kim ) 한국공업화학회 2009 공업화학 Vol.20 No.5

연구논문 : 비알코올성 지방간질환에서 nonalcoholic fatty Liver diseases activity score (NAS)의 유용성 평가 및 임상적 요소와의 상관성

이경훈 ( Kyung Hun Lee ),박상훈 ( Sang Hoon Park ),김유진 ( Yu Jin Kim ),허경림 ( Kyung Rim Huh ),민광선 ( Kwang Seon Min ),전선영 ( Sun Young Jun ),김경오 ( Kyoung Oh Kim ),박철희 ( Cheol Hee Park ),한태호 ( Taeho Hahn ),유교상 ( 대한간학회 2010 Clinical and Molecular Hepatology(대한간학회지) Vol.16 No.1

목적: NASH란 비만, 인슐린저항성, 2형 당뇨병, 고혈압, 고지혈증 등이 포함되는 대사증후군에서 나타나는 간질환으로 진단에 있어서 알코올 섭취 병력과 간생검 조직검사가 매우 중요하다. 그 동안 간생검 조직검사의 진단에 있어서 1999년 Brunt 등이 제시한 분류 체계를 사용해 왔는데, 2005년 NAS가 Kleiner등에 의해 제안되었다. 본 연구는 한국인 NASH환자에 대하여 NAS의 유용성 및 임상지표와의 연관성에 대하여 알아보고자 하였다. 대상 및 방법: 1999년부터 2007년까지 임상적으로 NASH로 진단 받고 초음파 유도하 간조직생검을 시행한 56예의 환자를 대상으로 분석을 시행하였다. 두 명의 병리의사가 같은 조직을 서로 다른 각각의 분류 체계를 이용하여 평가하였다. 중성지방을 포함한 혈청 지질과 CRP, 허리둘레, 체질량지수, 수축기혈압, 이완 기혈압, HOMA-IR 같은 대사증후군의 인자들과 공복 시 포도당, leptin, ferritin, 인슐린, C-peptide 비율 등의 생화학적 요소들을 측정하였다. 결과: 환자들의 평균 나이는 32.1±12.5세였으며 44명(78.6%)이 남자였다. 두 분류 체계에서 차이를 보이는 환자들은 약간의 지방 변성과 풍선양 변화와 섬유화를 동반한 환자들이었다. NAS 3, 4점의 borderline은 전체 판독 예 중 36.6%였다. 두 병리의사의 진단 일치도는 카파 값이 0.748(P<0.001)로 우수하였다. NAS가 높을수록 공복 시 혈당과 ALT, 중성지방이 증가되어 있었다. 결론: NAS는 한국인의 NASH진단에 있어서 간단하고 재연성이 좋은 분류 체계이다. Background/Aim: Nonalcoholic steatohepatitis (NASH) is commonly diagnosed using the semi-quantitative grading and staging system proposed by Brunt et al. in 1999. The Pathology Committee of the NASH established the nonalcoholic fatty liver diseases (NAFLD) activity score (NAS) in 2005. The aim of this study was to elucidate the validity and reliability of the NAS in Korean NAFLD patients. Methods: Fifty-six patients on whom sonography-guided liver biopsy for well-defined NAFLD was performed between 1999 and 2007 were identified retrospectively. Two pathologists evaluated each biopsy sample. NAFLD was evaluated using both the grading system developed by Brunt et al. and the NAS. Each pathologist was blinded to the patients` clinical data and scored independently. We evaluated the body mass index (BMI), liver enzymes, lipid profile, peripheral insulin resistance, leptin, insulin/c-peptide ratio, ferritin, and fasting blood glucose. Results: The patients were aged 32.1±12.5 years (mean±SD) and comprised 44 males (78.6%). Patients with different grades at the two grading systems had mild steatosis or ballooning changes with fibrosis, and 36.6% of them were borderline cases (NAS of 3 or 4). The interobserver agreement on diagnostic category was 0.748 (P<0.001) for the NAS (using weighted κ statistics). Elevated fasting glucose, ALT, and triglyceride were associated with the NAS. Conclusions: The simple and reproducible NAS was found to be a useful pathologic grading system in Korean NAFLD patients. However, the proportion of borderline cases based on the NAS was high. The "wait and see" strategy is necessary for evaluating the long-term prognosis. (Korean J Hepatol 2010;16:29-37)

압축형 화약 등방압축성형 공정 개선에 대한 연구

이경훈(Kyung hun Lee),박성일(Seong ill Park),장수호(Soo ho Chang) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.11