한자교육(漢字敎育)의 보편화(普遍化) -한글전용반대운동(專用反對運動)의 효과(效果)와 금후(今後)의 국민교육(國民敎育)의 정도(正道)를 중심(中心)으로-

류근수 한국어문교육연구회 1980 어문연구(語文硏究) Vol.8 No.1-2

HSR(Hybrid Surface Rainfall) 기반 레이더 합성강우 추정

류근수,정성화,권수현,박홍목,이규원,석미경 한국기상학회 2015 한국기상학회 학술대회 논문집 Vol.2015 No.4

혼합 최저고도각 반사도 자료를 이용한 레이더 강우추정 정확도 향상

류근수,정성화,남경엽,권수현,이청룡,이규원 한국지구과학회 2015 韓國地球科學會誌 Vol.36 No.1

레이더 반사도를 이용한 강수추정의 개선을 위해 새로운 접근 방식인 경북대학교에서 개발한 하이브리드 고도면을 이용한 강수량 추정기법(Hybrid Surface Rainfall, KNU-HSR)을 사용하였다. KNU-HSR기법은 지형에코와 레이더 빔차폐의 영향을 받지 않는 2차원 하이브리드 고도면에서의 반사도를 이용하여 강수량을 추정한다. 본 연구에서는 정적 HSR 및 동적 HSR기법이 사용되었으며 비교·검증되었다. 정적 HSR은 빔차폐지도와 지형에코지도를 사용하며, 동적 HSR은 정적 HSR에 추가적으로 실시간 퍼지로직 품질관리를 통한 품질지수지도를 사용한다. 검증을 위해 상관계수(correlation coefficient), 총비율(total ratio), 평균편의(mean bias), 정규화된 표준편차(normalized standard deviation), 평균상대오차(mean relative error)를 사용하였으며, 10개 강우사례의 지상우량계 강우자료를 이용하여 두 HSR의 강우추정 성능을 평가하였다. 모든 검증지수에서 동적 HSR은 반사도 보정을 하지 않은 정적 HSR에 비해 더 우수한 성능을 보였다. 동적 HSR은 레이더로부터 근거리에서는 과대추정하였으며 원거리에서는 빔 폭 확장 및 빔 고도증가로 인해 과소추정하였다. 동적 HSR의 정규화된 표준편차와 평균상대오차는 레이더로부터의 거리에 관계없이 가장 좋은 결과를 보였다. 정적 HSR은 약한 강우강도에서 상당히 과대추정하였으나 동적 HSR은 모든 강우강도에서 1.0에 총비율을 보였다. 반사도의 시스템오차 보정 후, 동적 HSR의 정규화된 표준편차와 평균상대오차는 각각 약 20%와 15%로 개선되었다. A novel approach, hybrid surface rainfall (KNU-HSR) technique developed by Kyungpook Natinal University, was utilized for improving the radar rainfall estimation. The KNU-HSR technique estimates radar rainfall at a 2D hybrid surface consistings of the lowest radar bins that is immune to ground clutter contaminations and significant beam blockage. Two HSR techniques, static and dynamic HSRs, were compared and evaluated in this study. Static HSR technique utilizes beam blockage map and ground clutter map to yield the hybrid surface whereas dynamic HSR technique additionally applies quality index map that are derived from the fuzzy logic algorithm for a quality control in real time. The performances of two HSRs were evaluated by correlation coefficient (CORR), total ratio (RATIO), mean bias (BIAS), normalized standard deviation (NSD), and mean relative error (MRE) for ten rain cases. Dynamic HSR (CORR=0.88, BIAS=-0.24mmhr-1, NSD=0.41, MRE=37.6%) shows better performances than static HSR without correction of reflectivity calibration bias (CORR=0.87, BIAS=-2.94mmhr-1, NSD=0.76, MRE=58.4%) for all skill scores. Dynamic HSR technique overestimates surface rainfall at near range whereas it underestimates rainfall at far ranges due to the effects of beam broadening and increasing the radar beam height. In terms of NSD and MRE, dynamic HSR shows the best results regardless of the distance from radar. Static HSR significantly overestimates a surface rainfall at weaker rainfall intensity. However, RATIO of dynamic HSR remains almost 1.0 for all ranges of rainfall intensity. After correcting system bias of reflectivity, NSD and MRE of dynamic HSR are improved by about 20% and 15%, respectively.

환경교육을 실천한다 - 향토학교 어린이 자연교실

류근수 세계평화교수협의회 1996 廣場 Vol.205 No.-

HSR (Hybird Surface Rainfall) 기반 강우추정 및 정확도 분석

류근수,정성화,이규원,권수현,김경익 한국기상학회 2014 한국기상학회 학술대회 논문집 Vol.2014 No.10

기상청 기상레이더 관측망을 이용한 합성 하이브리드 고도면 강우량(HSR)의 정확도 검증

류근수,정성화,오영아,박홍목,이규원 한국지구과학회 2017 한국지구과학회지 Vol.38 No.7

This study presents a new nationwide quantitative precipitation estimation (QPE) based on the hybrid surface rainfall (HSR) technique using the weather radar network of Korea Meteorological Administration (KMA). This new nationwide HSR is characterized by the synthesis of reflectivity at the hybrid surface that is not affected by ground clutter, beam blockage, non-meteorological echoes, and bright band. The nationwide HSR is classified into static (STATIC) and dynamic HSR (DYNAMIC) mosaic depending on employing a quality control process, which is based on the fuzzy logic approach for single-polarization radar and the spatial texture technique for dual-polarization radar. The STATIC and DYNAMIC were evaluated by comparing with official and operational radar rainfall mosaic (MOSAIC) of KMA for 10 rainfall events from May to October 2014. The correlation coefficients within the block region of STATIC, DYNAMIC and MOSAIC are 0.52, 0.78, and 0.69, respectively, and their mean relative errors are 34.08, 30.08, and 40.71%. 본 연구는 기상청의 기상레이더 관측망을 이용한 하이브리드 고도면 강우추정 기법 기반의 새로운 정량적 합성강수량 추정 방법을 제시한다. HSR기법은 지형클러터, 빔차폐, 비 기상 에코 및 밝은 띠의 영향을 받지 않는 하이브리드 고도면의 반사도를 합성하는 것이 특징이다. HSR 합성반사도는 정적 HSR (STATIC)과 단일편파레이더에 대한 퍼지로직 기법과 이중편파레이더에 대한 시선방향 질감 기반의 품질관리 절차를 사용하는 동적 HSR (DYNAMIC) 합성으로 구분된다. STATIC과 DYNAMIC은 2014년 5월부터 10월까지 10개의 강우 사례에 대해 기상청 현업용 합성강우(MOSAIC)와 비교검증 하였다. 차폐 영역에서 STATIC, DYNAMIC, MOSAIC의 상관계수는 각각 0.52, 0.78, 0.69이며평균 상대 오차는 각각 34.08, 30.08, 40.71%로 분석되었다.

인대 거동의 수치해석 모델 ( A numerical analysis model of ligament behaviour )

류근수,민옥기,백형선 대한기계학회 1999 대한기계학회 춘추학술대회 Vol.- No.-

A retrospective study of the long-term survival of RESTORE® dental implants with resorbable blast media surface

류근수,김필종,김성태,조영단,구영 대한치주과학회 2023 Journal of Periodontal & Implant Science Vol.53 No.6

Purpose: The aim of this study was to retrospectively evaluate the survival and failure rates of RESTORE® implants over a follow-up period of 10–15 years at a university dental hospital and to investigate the factors affecting the survival rate of these dental implants. Methods: A total of 247 RESTORE® dental implants with a resorbable blast media (RBM) surface inserted in 86 patients between March 2006 and April 2011 at the Department of Periodontology of Seoul National University Dental Hospital were included. Patients with follow-up periods of less than 10 years were excluded, and data analysis was conducted based on dental records and radiographs. Results: Over a 10- to 15-year period, the cumulative survival rate of the implants was 92.5%. Seventeen implants (6.88%) were explanted due to implant fracture (n=10, 4.05%), periimplantitis (n=6, 2.43%), and screw fracture (n=1, 0.4%). The results of univariate regression analysis using a Cox proportional hazards model demonstrated that implants placed in male patients (hazard ratio [HR], 4.542; 95% confidence interval [CI], 1.305–15.807; P=0.017) and implants that supported removable prostheses (HR, 15.498; 95% CI, 3.105–77.357; P=0.001) showed statistically significant associations with implant failure. Conclusions: Within the limitations of this retrospective study, the RESTORE® dental implant with an RBM surface has a favorable survival rate with stable clinical outcomes.

Effects of adjacent periodontitis on osseointegrated dental implants

류근수,김경화,조영단,설양조,구영 대한치주과학회 2024 Journal of Periodontal & Implant Science Vol.54 No.4

Purpose: This study aimed to investigate whether new-onset periodontitis or apical periodontitis in the adjacent teeth affects osseointegrated dental implants in a beagle dog model. Methods: One control group and 2 experimental groups (periodontitis and apical periodontitis groups) were defined based on the presence of experimental periodontitis or apical periodontitis, with 1 beagle dog randomly assigned to each group. The mandibular second and fourth premolars on both sides of the 3 beagles were extracted. Eight weeks after extraction, 4 bone-level implant fixtures, 2 on both sides of each mandible, were placed in each beagle. Six weeks after implant surgery, healing abutments were connected. After sufficient osseointegration, plaque control was performed in the control group, while periodontitis and apical periodontitis were induced in the experimental groups. The beagles were euthanized for histological analyses 20 weeks after induction of experimental periodontitis. Statistical analyses were performed using the Kruskal–Wallis test with the Bonferroni correction to compare the 3 groups. Results: The implants in the control and apical periodontitis groups were well-maintained, while those in the periodontitis group showed clinical signs of inflammation with bone resorption. The bone-to-implant contact (BIC) and bone area values in the periodontitis group were lower than those in the other groups. The distance between the implant shoulder and the first BIC was significantly greater in the periodontitis group than in the control group (P<0.05). Conclusions: The presence of periodontitis in adjacent teeth can pose a risk to dental implants, potentially resulting in peri-implantitis. However, this was not observed for apical periodontitis. Within the limitations of this study, periodontal care is necessary to reduce the impact of periodontitis in adjacent teeth on osseointegrated implants.

인류평화를 위한 지식인의 책임

류근수 세계기독교통일신령협회 2001 統一世界 Vol.- No.12