능동소음제어 및 그 응용

남현도(南炫道) 대한전기학회 1999 전기의 세계 Vol.48 No.6

적응시간 간격 알고리즘을 이용한 KIM의 계산 효율성 개선

남현,최석진 한국기상학회 2023 대기 Vol.33 No.4

A numerical forecasting models usually predict future states by performing time integration considering fixed static time-steps. A time-step that is too long can cause model instability and failure of forecast simulation, and a time-step that is too short can cause unnecessary time integration calculations. Thus, in numerical models, the time-step size can be determined by the CFL (Courant-Friedrichs-Lewy)-condition, and this condition acts as a necessary condition for finding a numerical solution. A static time-step is defined as using the same fixed time-step for time integration. On the other hand, applying a different time-step for each integration while guaranteeing the stability of the solution in time advancement is called an adaptive time-step. The adaptive time-step algorithm is a method of presenting the maximum usable time-step suitable for each integration based on the CFL-condition for the adaptive time-step. In this paper, the adaptive time-step algorithm is applied for the Korean Integrated Model (KIM) to determine suitable parameters used for the adaptive time-step algorithm through the monthly verifications of 10-day simulations (during January and July 2017) at about 12 km resolution. By comparing the numerical results obtained by applying the 25 second static time-step to KIM in Supercomputer 5 (Nurion), it shows similar results in terms of forecast quality, presents the maximum available time-step for each integration, and improves the calculation efficiency by reducing the number of total time integrations by 19%.

열중량분석법에 의한 건조 하수슬러지의 연소 속도 및 특성 평가

남현,박소미,임혁,정성배,김철규 한국열환경공학회 2015 한국열환경공학회 학술대회지 Vol.2015 No.추계

Characterization of Primary Epithelial Cells Derived from Human Salivary Gland Contributing to in vivo Formation of Acini-like Structures

남현,김지혜,황지윤,김지혜,김재완,장미,이종호,박경표,이진 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.6

Patients with head and neck cancer are treated with thera-peutic irradiation, which can result in irreversible salivary gland dysfunction. Because there is no complete cure for such patients, stem cell therapy is an emerging alternative for functional restoration of salivary glands. In this study, we investigated in vitro characteristics of primarily isolated epithelial cells from human salivary gland (Epi-SGs) and in vivo formation of acini-like structures by Epi-SGs. Primarily isolated Epi-SGs showed typical epithelial cell-like morphology and expressed E-cadherin but not N-cadherin. Epi-SGs expressed epithelial stem cell (EpiSC) and embryonic stem cell (ESC) markers. During long-term culture, the expression of EpiSC and ESC markers was highly detected and maintained within the core population with small size and low cytoplasmic complexity. The core population expressed cytokeratin 7 and cytokeratin 14, known as duct markers indicating that Epi-SGs might be originated from the duct. When Epi-SGs were transplanted in vivo with Matrigel, acini-like structures were readily formed at 4 days after transplan-tation and they were maintained at 7 days after transplantation. Taken together, our data suggested that Epi-SGs might contain stem cells which were positive for EpiSC and ESC markers, and Epi-SGs might contribute to the regeneration of acini-like struc-tures in vivo. We expect that Epi-SGs will be useful source for the functional restoration of damaged salivary gland.

일부 도시지역의 당뇨병 관리실태와 혈당관리 수준과 관련된 요인

남현,신민호,권순석,오현숙,이정애,최진수 대한임상건강증진학회 2012 Korean Journal of Health Promotion Vol.12 No.3

Background: We evaluated the current status of diabetes management and the predictors for poor glycemic control in an urban area. Methods: This study included 1,138 community-dwelling adults (≥50 years) with diabetes, of which 584 participated in the diabetes care survey. Logistic regression was used to identify the factors predicting poor glycemic control (hemoglobin A1c [HbA1c]≥7%) in the total sample and to evaluate the relationship between the history of diabetes management checkup and poor glycemic control in the diabetes care survey sample. Results: Of the 1,138 patients, 53.2% had blood pressure less than 130/80 mmHg, 41.7% had fasting glucose between 70 and 130 mg/dL, 48.6% had HbA1c below 7.0%, 60.1% had triglycerides below 150 mg/dL, 41.4%had low density lipoprotein cholesterol below 100 mg/dL, and 59.1% had normoalbuminuria (urine albuminto-creatinine ratio <30 mg/g creatinine). Of the 584 patients completing the diabetes care survey, 63.9% had one or more lipid tests, 32.0% had one or more HbA1c tests, 43.8% had one or more microalbuminuria tests,and 42.5% had one or more fundoscopic examinations annually. Female gender (odds ratio [OR], 1.71; 95%confidence interval [CI], 1.23-2.36), duration of diabetes (OR, 1.07; 95% CI, 1.06-1.09), and alcohol use (OR,1.40; 95% CI, 1.06-1.85) were associated with an increased risk for poor glycemic control while age (OR, 0.97;95% CI, 0.96-0.99) and antihypertensive medication (OR, 0.64; 95% CI, 0.50-0.83) were associated with a decreased risk. Conclusions: This study shows that glycemic control is likely to be poor in urban areas. We need to develop appropriate community-based strategies to achieve optimal glycemic control and prevent diabetes complications. 연구배경: 본 연구는 도시지역 당뇨병 환자들의 관리 현황과 혈당 관리에 영향을 미치는 요인들을 파악하고자 하였다. 방법: 본 연구의 대상은 도시지역에 거주하는 50세 이상당뇨병환자 1,138명이며 그중 584명에 대해 당뇨병 관리에 대한 설문조사가 이루어졌다. 당화혈색소가 7.0% 이상일 때 혈당관리가 미흡하다고 정의하고 다변량 로지스틱분석을 이용하여 전체 대상자에서 혈당관리 수준에 영향을 주는 요인들을 파악하였고 당뇨병 관리 설문조사에 응한 584명에서 당뇨병 관리 검사력과 혈당 관리 수준과의관련성을 알아보았다. 결과: 전체 1138명 중 혈압 130/80 mmHg 미만은53.2%, 공복혈당 70-130 mg/dL 41.7%, 당화혈색소 7%미만은 48.6%, 중성지방 150 mg/dL 미만 60.1%, 저밀도지단백 콜레스테롤 100 mg/dL 미만 41.4%, 미세알부민뇨음성 59.1%였다. 당뇨관리 설문조사를 받은 584명 중 최근1년 이내의 합병증 검사비율은 고지혈증 검사 63.9%, 당화혈색소 검사 32.0%, 미세알부민뇨 검사 43.8%, 그리고 안저검사 42.5% 이었다. 다변량 로지스틱 회귀분석에서 여성(odds ratio [OR], 1.71; 95% confidence interval [CI],1.23-2.36), 당뇨병 유병기간(OR, 1.07; 95% CI, 1.06-1.09)이 긴 경우, 음주(OR, 1.40; 95% CI, 1.06-1.85)를 하는 경우에서 혈당관리가 미흡하였고 고연령층에서(OR, 0.97;95% CI, 0.96-0.99), 항고혈압제를 복용(OR, 0.64; 95%CI, 0.50-0.83)한 경우에서 혈당관리가 잘 되었다. 결론: 본 연구는 도시지역 당뇨병 환자들의 당뇨병 관리상태가 좋지 않음을 보여주고 있다. 지역사회 당뇨병 환자들의 적절한 혈당 관리와 합병증의 예방을 위해서는 지역사회에 기반을 둔 관리 대책의 수립이 필요할 것으로 생각된다.

역사속의 민족의 아픔은 민족종교가 해결해야 한다 : 청산되지 않은 한·일 관계와 민족종교의 역할

남현 중앙승가대학교 1996 僧伽 Vol.13 No.-

Expression Profile of the Stem Cell Markers in Human Hertwig’s Epithelial Root Sheath/Epithelial Rests of Malassez Cells

남현,이진,Jaewon Kim,박재완,박주철,김정욱,서병무,Jae Cheoun Lee 한국분자세포생물학회 2011 Molecules and cells Vol.31 No.4

Hertwig’s epithelial root sheath/Epithelial rests of Malassez (HERS/ERM) cells are unique epithelial cells in the periodontal ligament. They remain in periodontal tissues throughout the adult life, and it is expected that their functional role is to maintain the homeostasis of the periodontium through reciprocal interactions with other periodontal cells. In this study, we investigated whether HERS/ERM cells have primitive stem cell characteristics: those of embryonic stem cells as well as of epithelial stem cells. Primary HERS/ERM cells had typical epithelial cell morphology and characteristics and they maintained for more than five passages. They expressed epithelial stem cell-related genes: ABCG2, ΔNp63, p75, EpCAM, and Bmi-1. Moreover,the expression of embryonic stem cell markers such as Oct-4, Nanog, and SSEA-4 were detected. Next, we investigated whether the expression of these stem cell markers was maintained during the sub-culture process. HERS/ERM cells showed different expression levels of these stemness genes at each passage, but their expression was maintained throughout the passages. Taken together,our data suggest that a primary culture of HERS/ERM cells contains a population of primitive stem cells that express epithelial stem cell markers and embryonic stem cell markers. Furthermore, these cell populations were maintained during the sub-culturing process in our culture conditions. Therefore, our findings suggest that there is a strong possibility of accomplishing cementum tissue engineering with HERS/ERM cells.

비정역학 오일러 방정식계에 수평명시-연직암시(HEVI) 시간이산화기법 적용

남현,최석진 한국기상학회 2021 한국기상학회 학술대회 논문집 Vol.2021 No.10

대기 운동 지배 방정식계의 수치적 계산에 있어서 용이한 시간 차분법은 명시적 기법이다. 일반적으로 이 기법을 통해 모든 파동을 수치적으로 정확하게 계산하는 것이 가장 효과적일 것이다. 그러나 명시적 기법은 느리게 진행하는 대규모 파동의 경우 수치적 안정도를 유지하면서 적분할 수 있지만, 음파나 중력파의 경우 수치적 안정도를 확보하기 위해서는 명시적 기법의 적분 시간 간격이 아주 작아야만 한다. 나아가 고해상도 운용을 고려한다면 격자 크기가 상세화되기 때문에 수치적 안정성 확보를 위해 적분 시간 간격이 더욱 작아지고 이에 따른 계산비용 증가는 필연적이다. 따라서 고해상도에서의 명시적 기법 적용에 따른 계산비용 증가를 극복하기 위해서 준암시적 시간 차분법을 적용하고자 한다. 본 연구에서는 대기 운동 지배 방정식계에 준암시적 시간 차분법을 적용하여 고해상도 운용에 따른 계산비용 증가를 극복하고자 한다. 이때, 지배 방정식계는 한국형 전지구 수치예보시스템(Korean Integrated Model, KIM)에서 고려한 비정역학 오일러 방정식계이다. 준암시적 기법으로는 수평명시-연직암시(Horizontal Explicit-Vertical Implicit, HEVI) 기법을 고려한다. 이 기법은 수평 미분에 대해서는 명시적 기법을 적용하고 연직 방향의 미분에 대해서만 암시적 기법을 적용한다. 수치 해법에서 암시적 부분을 풀기 위해서 각각 변수의 연직 방향으로의 선형 행렬식을 구성하고 일반화된 최소 잔차법(Generalized Minimal RESidual method, GMRES)을 이용하여 수치적 해를 얻는다. 이 기법의 적용을 통해 모델의 수치예보 정확도를 유지하면서 수치적 안정도를 확보하고자 한다. 또한, KIM의 이상실험 수치 결과들을 바탕으로 비정역학 오일러 방정식계에서 HEVI 기법의 특징을 비교 분석한다.

Association between Serum 25-hydroxyvitamin D Levels and Type 2 Diabetes in Korean Adults

남현,김혜연,최진수,권순석,이영훈,남해성,박경수,류소연,최성우,오수현,김선아,신민호 전남대학교 의과학연구소 2017 전남의대학술지 Vol.53 No.1

Previous studies have suggested that a vitamin D deficiency increases the risk of type 2 diabetes. This study evaluated the association between serum vitamin D levels and type 2 diabetes in Korean adults. This study included 9,014 subjects (3,600 males and 5,414 females) aged ≥50 years who participated in the Dong-gu Study. The subjects were divided into groups in whom the serum vitamin D level was severely deficient (<10 ng/mL), deficient (10 to <20 ng/mL), insufficient (20 to <30 ng/mL) and sufficient (≥30 ng/mL). Type 2 diabetes was defined by a fasting blood glucose level of ≥126 mg/dL and/or an HbA1c proportion of ≥6.5% and/or self-reported current use of diabetes medication. Multiple logistic regression was performed to evaluate the association between vitamin D status and type 2 diabetes. The age- and sex-adjusted prevalence of type 2 diabetes was 22.6%, 22.5% and 18.4% and 12.7% for severely deficient, deficient, insufficient, and sufficient, respectively. Multivariate modeling revealed that subjects with insufficient or sufficient vitamin D levels were at a lower risk of type 2 diabetes than were subjects with deficient vitamin D levels [odds ratio (OR), 0.82; 95% confidence interval (CI), 0.71-0.94 and OR, 0.51; 95% CI, 0.35-0.74, respectively]. Higher serum vitamin D levels were associated with a reduced risk of diabetes in Korean adults, suggesting that vitamin D may play a role in the pathogenesis of diabetes.

Articular Eminence Morphology of Temporomandibular Joint in Young Korean Adults

남현,심영주,강진규 대한안면통증∙구강내과학회 2019 Journal of Oral Medicine and Pain Vol.44 No.2

Purpose: The aim of this study was to analyse and evaluate the morphology of the articular eminence of temporomandibular joint in young Korean adults using cone-beam computed tomography (CBCT). Methods: One hundred seventy-one subjects (59 males, 112 females) in the 20s were examined using CBCT. Width and height of articular eminence, top-roof line angle, best-fit line angle, joint space were measured. For the group comparisons, independent t-test was used with the level of significance established at p≤0.05. Results: In asymptomatic young Korean adults, average eminence width was 9.49±1.62 mm in males and 9.33±1.36 mm in females. Average eminence height was 7.23±1.81 mm in males and 6.82±1.31 mm in females. Average eminence inclination of measured by toproof line angle was 37.09o±7.74o in males and 36.12o±5.65o in females. Average eminence inclination measured by best-fit line angle was 50.79o±11.49o in males and 48.43o±9.05o in females. Average joint space was 3.03±0.67 mm in males and 2.63±0.68 mm in females. Conclusions: Increasing age did not affect the morphology of the articular eminence in asymptomatic young Korean adults. Males had slightly larger eminence width, height, toproof line angle, best-fit line angle and joint space, but no statistical significance (p>0.05) was observed only in the joint space (p=0.001). There was no side-to-side difference in morphology (p>0.05).