• Journal of Periodontal and Implant Science
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• 제39권1호
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• pp.17-26
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• 2009

Purpose: The non-carious cervical lesion(NCCL) is a loss of tooth structure at the neck of affected teeth that is unrelated to tooth caries. The reported prevalence of NCCL varies from 5% to 85%. Prevalence and severity of lesions have been found to increase with age. They are becoming more significant as people live longer and become more aware of the importance of oral health. The purposes of this study were first, to examine the periodontal conditions associated with NCCL, and second, to investigate the clinical effects of class V restorations of NCCL on periodontal tissues. Materials and methods: The sample size was 982 teeth of 50 subjects(25 male, mean age $52{\pm}7$) who were seen at the Department of Periodontology, Pusan National University Hospital. At the baseline examination, clinical periodontal parameters were measured. After the initial examination, 24 patients who were absent from hypersensitivity were selected. The teeth with NCCL were randomly divided into the test and control groups. The teeth in the test group were restored with flowable resin; the control teeth were not restored. Six months later, the clinical examinations were repeated. The data were analyzed using the SPSS program. Results: The results were as follows: 1) NCCL occurred on 45.8% of examined teeth. The percentage of affected teeth was higher in maxillary and premolar teeth. 2) The shallow saucer type was the most common. 3) Teeth with NCCL had more gingival recession, lower attachment level, and higher incidences of bleeding on probing(BOP) and plaque than NCCL-free teeth. 4) Six months later, gingival recession, attachment level, the percentages of BOP and plaque in the test group were lower than in the control group(p<0.05). Conclusion: NCCLs were more found in maxillary teeth, especially in premolar teeth. The results suggest that the restoration of NCCL could affect some periodontal parameters favorably.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.64-67
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• 2008

This study investigated the influence of composite resins with different elastic moduli and occlusal loading conditions on the stress distribution of restored notch-shaped non-carious cervical lesions (NCCL) using 3D finite element analysis. Two different materials, Tetric Flow and Z100, were used as representative flowable hybrid resins for the restoration of NCCL. A static point load of 500 N was applied at the buccal and palatal cusps. The ratios of stress reduction to energy dissipation were better in the compressive state than the tensile state regardless of the restorative material. The total dissipation ratios for Tetric Flow were 1.5% and 4.2% larger than those for Z100 under compression and tension, respectively. Therefore, tensile stress poses more of a risk for tooth fracture, and Tetric Flow is a more appropriate material for restoration.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.191-192
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• 2008

• 대한치과의사협회지
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• 제48권4호
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• pp.297-307
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• 2010

Noncarious cervical lesions(NCCLs) are characterized as structural defects found on the tooth surface of the cement-enamel junction. Loss of tooth structure through noncarious mechanisms may vary in etiology and clinical presentation for each individual but presently many clinician now classify this as tooth failure of abfraction due to the stress applied in the cervical area of the tooth under oral physiological and pathological loads. In the current study, we investigated the stress distribution of maxillary premolar with NCCL using simulated 3D finite element analysis. The results were as follows: 1. In the sound maxillary premolar, the stresses were highly concentrated at cervical enamel surface of the mesiobuccal line angle, asymmetrically. 2. Once the lesion has been formed, the highest stress concentration was observed around the apex of the wedge shaped lesion. 3. In four types of NCCL, the patterns of stress distribution were similar and the peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 4. Lesion cavity modification of rounding apex, reduced stress of lesion apex. 5. When restoring the notch-shaped lesion, material with high elastic modulus worked well at the lesion apex and material with low elastic modulus worked well at the cervical cavosurface margin.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.911-931
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• 2021

Recently, most cloud services use Docker container environment to provide their services. However, there are no researches to evaluate the performance of communication libraries for multi-GPU based distributed deep learning in a Docker container environment. In this paper, we propose an efficient communication architecture for multi-GPU based deep learning in a Docker container environment by evaluating the performances of various communication libraries. We compare the performances of the parameter server architecture and the All-reduce architecture, which are typical distributed deep learning architectures. Further, we analyze the performances of two separate multi-GPU resource allocation policies - allocating a single GPU to each Docker container and allocating multiple GPUs to each Docker container. We also experiment with the scalability of collective communication by increasing the number of GPUs from one to four. Through experiments, we compare OpenMPI and MPICH, which are representative open source MPI libraries, and NCCL, which is NVIDIA's collective communication library for the multi-GPU setting. In the parameter server architecture, we show that using CUDA-aware OpenMPI with multi-GPU per Docker container environment reduces communication latency by up to 75%. Also, we show that using NCCL in All-reduce architecture reduces communication latency by up to 93% compared to other libraries.

• Journal of Periodontal and Implant Science
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• 제34권3호
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• pp.647-657
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• 2004

A non-carious cervical lesion(NCCL) is the loss of tooth structure at the cementoenamel junction level that is unrelated to dental caries. This study was to evaluate the occlusal and periodontal status of teeth with non-carious cervical lesions. We evaluated 105 teeth with non-carious cervical lesions in 35 subjects aged 38-75 years and characterized them based on the shape and dimension, plaque retention, bleeding on probing(BOP), probing pocket depth(PPD), occlusal status, brushing type, hypersensitivity and wear facet. The results of this study were as follows 1. No significant association was observed between cervical lesions and occlusal contact in lateral excursions. 2. No significant difference occurred in plaque retention, PPD, BOP between teeth with and without cervical lesions. 3. Test teeth had a significantly higher percentage of hypersensitivity and occlusal wear facet than teeth without cervical lesions. 4. Wedge shaped lesions had a significantly higher percentage of plaque than saucer shaped lesions. 5. Teeth with plaque were found to have significantly deeper PPD than teeth without plaque retention in cervical regions. 6. Teeth with occlusal contacts were found to have significantly deeper PPD than teeth without occlusal contacts. 7. No significant association was observed between cervical lesions and PPD independent of plaque retention and occlusal contacts Although more knowledge is necessary, our results suggest that occlusal contact and bacterial plaque may influence on periodontal tissue, but NCCL is not directly associated with periodontal health

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2023년도 추계학술발표대회
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• pp.2-4
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• 2023

KISTI의 GPU 클러스터 시스템인 뉴론은 NVIDIA의 A100과 V100 GPU가 총 260개 탑재되어 있는 클러스터 시스템이다. 뉴론의 계산노드들은 고성능의 인터커넥트인 Infiniband(IB) 케이블로 연결되어 있어 멀티 노드 작업 수행 시에 고대역 병렬통신이 가능하다. 본 논문에서는 NVIDIA사에서 제공하는 NCCL의 벤치마크 코드를 이용하여 인터커넥트 네트워크의 통신 성능을 비교분석하는 방안에 대해서 소개한다.

• Journal of Periodontal and Implant Science
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• 제52권2호
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• pp.91-115
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• 2022

Purpose: This systematic review aimed to compare the efficacy, defined in terms of the mean percentage of root coverage (mRC), of surgical treatment approaches combined with adhesive restorations of non-carious cervical lesions (NCCLs) to that of root coverage alone in patients with a single gingival recession (GR) and NCCL. Methods: A literature search was conducted to identify longitudinal studies reporting the mRC following treatment for the correction of GR defects associated with NCCLs using a combination of surgical and restorative techniques in systemically and periodontally healthy patients. Results: The search resulted in the retrieval of 12,409 records. Seven publications met the inclusion criteria for the qualitative synthesis of data. The mRCs ranged from 69% to 97%. In the medium term, the gingival margin position was more stable when a connective tissue graft (CTG) was used, independently of whether restoration of teeth with NCCLs was performed. Conclusions: The strength of the evidence was limited by methodological heterogeneity in terms of study design as well as the unit and period of analysis, which precluded a metaanalysis. Although no definitive conclusion could be drawn due to the lack of sufficient evidence to estimate the effectiveness of the interventions, CTG-based procedures contributed to gingival margin stability regardless of the performance of restoration to treat NCCLs.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2728-2735
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• 2022

The research on the flow and heat transfer characteristics of lead bismuth(LBE) is significant for the thermal-hydraulic calculation, safety analysis and practical application of lead-based fast reactors(LFR). In this paper, a new CFD model is proposed to solve the thermal-hydraulic analysis of LBE. The model includes two parts: turbulent model and turbulent Prandtl, which are the important factors for LBE. In order to find the best model, the experiment data and design of 19-pin hexagonal rod bundle with spacer grid, undertaken at the Karlsruhe Liquid Metal Laboratory (KALLA) are used for CFD calculation. Furthermore, the turbulent model includes SST k - 𝜔 and k - 𝜀; the turbulent Prandtl includes Cheng-Tak and constant (Pr_t =1.5,2.0,2.5,3.0). Among them, the combination between SST k - 𝜔 and Cheng-Tak is more suitable for the experiment. But in the low Pe region, the deviation between the experiment data and CFD result is too much. The reason may be the inlet-effect and when Pe is in a low level, the number of molecular thermal diffusion occupies an absolute advantage, and the buoyancy will enhance. In order to test and verify versatility of the model, the NCCL performed by the Nuclear Thermal-hydraulic Laboratory (Nuthel) of Xi'an Jiao tong University is used for CFD to calculate. This paper provides two verification examples for the new universal model.

• Clinical and Experimental Pediatrics
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• 제48권1호
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• pp.40-47
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• 2005

목 적 : 인체의 세균성 호흡기감염 및 중추신경계 감염에 제일 중요하고 흔한 병원균인 폐구균은 전 세계적으로 다양한 항생제에 대한 내성이 발생되기 시작하여 점차 증가하며 최근에는 고도 내성균에 의한 중증 감염이 임상적으로 심각한 문제로 대두되고 있다. 특히 5세 이하의 어린 소아 연령에서 더욱 빈번하게 호흡기감염과 중추신경계 감염을 일으키는 특성이 있어 폐구균에 대한 항균력 평가에 대한 연구는 매우 중요하다. 이런 배경에 따라 국내 급성 중이염, 급성 부비동염 및 폐렴 환아에서 분리된 폐구균에 대하여 페니실린 내성을 파악하고 우리나라에서 이들 질환에 흔히 사용되고 있는 경구용 항생제인 amoxicillin, amoxicillin-clavulanate, cefaclor에 대한 항균력 평가를 실시하였다. 방 법 : 2000년 5월부터 2003년 6월 사이에 가톨릭의대 성모자애병원, 여의도 성모병원, 성빈센트병원, 성바오로병원, 대전성모병원, 고려의대 안산병원, 부산의대병원, 마산파티마병원, 인하의대병원에 외래 방문 또는 입원한 급성 중이염, 급성 부비동염 및 폐렴을 지닌 환아에서 분리 동정된 156개의 폐구균을 대상으로 하였다. 2003년 NCCLS의 기준에 의한 한천배지 희석법으로 페니실린에 대한 MIC를 일차적으로 확인하여 폐구균에 대한 페니실린 내성을 파악하였고, 급성 중이염, 급성 부비동염 및 폐렴에서의 내성률 차이를 확인하였으며, amoxicillin, amoxicillin-clavulanate, cefaclor에 대한 내성 정도를 파악하고 $MIC_{50}$ 및 $MIC_{90}$을 확인하여 감수성 차이를 비교하고 분석하였다. 결 과 : 급성 중이염, 급성 부비동염 및 폐렴 환아로부터 분리된 156 폐구균 검체에서 페니실린에 78.2%(중등도 내성률; 46.2%, 고도 내성률; 32.0%)의 높은 내성률이 확인되었고, 질환별로는 급성 부비동염의 페니실린 내성률이 71.4%, 급성 폐렴의 경우는 73.4%이었으나 급성 중이염의 경우는 92.7%로 두 질환에 비해 현저히 높은 차이점이 있음을 알 수 있었다. 한편 2003년 NCCLS 판정 MIC 기준에 따른 amoxicillin의 내성률은 16.7%(중등도 내성; 15.4%, 고도 내성; 1.3%)로 나타나 페니실린의 내성 결과와 뚜렷한 차이를 보였다. 그리고 amoxicillin-clavulanate의 경우는 내성률이 9.6%(중등도 내성 9.6%, 고도 내성; 0%)로 역시 penicillin 내성 결과와 현저히 다른 결과를 알 수 있었으며, amoxicillin보다도 내성률이 낮았고 고도 내성이 없는 결과를 보였다. 그러나 cefaclor의 내성 결과는 95.5%(중등도 내성 1.9%, 고도 내성; 93.6%)의 결과를 보여 매우 심각한 내성이 있음을 확인하였다. 결 론 : 본 연구 결과로 소아 급성 호흡기감염 환아로부터 분리된 폐구균에 대한 페니실린 내성이 매우 높음을 확인하였으며, 특히 급성 중이염 환아에서 분리된 폐구균에 대한 페니실린 내성이 가장 높아 급성 중이염 환아에게 항생제의 사용이 많았음을 추정할 수 있었다. 그러나 amoxicillin과 amoxicillin-clavulanate에 대한 항균력을 평가한 결과 amoxillin과 amoxicillin-clavulanate의 폐구균에 대한 내성은 페니실린보다 현저히 낮았고, 특히 amoxillin의 고도 내성률은 1.3%이었고, amoxicillin-clavulanate에서는 고도 내성을 보인 폐구균이 없는 결과를 보여 국내에서는 이들 항균제의 표준 용량으로 폐구균에 의한 소아 급성 호흡기감염 치료가 일차적으로 이루어 질 수 있음을 확인하였다. 반면 국내에서 경구 cephalosporin제 중 제일 사용이 많은 cefaclor의 경우는 95.5%의 내성을 보여 일차 약제로서의 역할이 없음을 알 수 있었다.