• Restorative Dentistry and Endodontics
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• 제48권2호
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• pp.13.1-13.11
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• 2023

Objectives: Natural extracts have been investigated as a biomimetic strategy to mechanically strengthen the collagen network and control the biodegradation of extracellular matrix. This study evaluated the effect of epigallocatechin-3-gallate (EGCG) on abfraction lesions prior to the composite resin. Materials and Methods: The sample consisted of 30 patients (aged between 28 and 60 years) with abfraction lesions located in 2 homologous premolars. The teeth were randomly assigned according to dentin treatment: 0.02% EGCG solution or distilled water (control). After enamel acid etching, the solutions were applied immediately for 1 minute. The teeth were restored with Universal Adhesive (3M) and Filtek Z350 XT (3M). Analyzes were done by 2 independent examiners using modified USPHS (retention, secondary caries, marginal adaptation, and postoperative sensitivity) and photographic (color, marginal pigmentation, and anatomical form) criteria at baseline (7 days) and final (18 months). The data analysis used Friedman and Wilcoxon signed-rank tests (α = 0.05). Results: At baseline, all restorations were evaluated as alpha for all criteria. After 18 months, restorations were evaluated as alpha for secondary caries, color, and marginal pigmentation. There was significant difference between baseline and 18 months (p = 0.009) for marginal adaptation and postoperative sensitivity (p = 0.029), but no significant difference were verified between treatments (p = 0.433). The EGCG group had a restoration retention rate of 93.3%, while the control group had 96.7%. Conclusions: The application of EGCG solution on abfraction lesions did not significantly influence the survival of the restorations based on clinical and photographic criteria.

• 천문학회보
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• 제46권2호
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• pp.49.1-49.1
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• 2021

We carried out simultaneous monitoring observations of five maser lines, H₂O (22 GHz), SiO 𝝊 =1, 2, J =1-0 (43.1, 42.8 GHz), and SiO 𝝊 =1, J=2-1, J =3-2 (86.2, 129.3 GHz), toward the Mira variable star WX Serpentis with the 21-m antennas of the Korean VLBI Network (KVN) in 2009-2021 (~12 years). Most spectra of the H₂O maser are well separated into two parts of two blue- and one redshifted features within ± 10 km s-1 of the stellar velocity. All detected SiO masers are generally concentrated within ± 5 km s-1 of the stellar velocity, and sometimes appear split into two components. Overall, the profiles of SiO and H₂O masers detected in WX Serpentis illustrate typical characteristics of the Mira variable. In addition, flux variations of both SiO and H₂O masers are well correlated with the optical light curve of the central star, showing a phase lag of ~ 0.1 for SiO masers and ~ 0.2 for H₂O maser. This phenomenon is considered to be the direct effect of propagating shock waves generated by the stellar pulsation, because SiO and H₂O masers are sequentially distributed at different positions with respect to the central star. In addition, we analyzed long-term trends and characteristics of maser velocities, maser ratio, and the velocity extents (the full width at zero power; FWZP). We also investigated a spectral energy distribution (SED) ranging from 1.2 to 240 ㎛ obtained using several infrared data: 2MASS, WISE, IRAS, ISO, COBE DIBRE, RAFGL, and AKARI (IRC and FIS). From the IRAS LRS and ISO SWS spectra of this star, we identified 9.7 and 12 ㎛ silicate emission features consistent with the SE6 spectrum model, corresponding to the typical AGB phase.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.469-484
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• 2023

A deep recursive bidirectional Cuda Deep Neural Network Long Short Term Memory (Bi-CuDNNLSTM) layer is recruited in this paper to predict the entire force time histories, and the corresponding hysteresis and backbone curves of reinforced concrete (RC) bridge piers using experimental fast and slow cyclic tests. The proposed stacked Bi-CuDNNLSTM layers involve multiple uncertain input variables, including horizontal actuator displacements, vertical actuators axial loads, the effective height of the bridge pier, the moment of inertia, and mass. The functional application programming interface in the Keras Python library is utilized to develop a deep learning model considering all the above various input attributes. To have a robust and reliable prediction, the dataset for both the fast and slow cyclic tests is split into three mutually exclusive subsets of training, validation, and testing (unseen). The whole datasets include 17 RC bridge piers tested experimentally ten for fast and seven for slow cyclic tests. The results bring to light that the mean absolute error, as a loss function, is monotonically decreased to zero for both the training and validation datasets after 5000 epochs, and a high level of correlation is observed between the predicted and the experimentally measured values of the force time histories for all the datasets, more than 90%. It can be concluded that the maximum mean of the normalized error, obtained through Box-Whisker plot and Gaussian distribution of normalized error, associated with unseen data is about 10% and 3% for the fast and slow cyclic tests, respectively. In recapitulation, it brings to an end that the stacked Bi-CuDNNLSTM layer implemented in this study has a myriad of benefits in reducing the time and experimental costs for conducting new fast and slow cyclic tests in the future and results in a fast and accurate insight into hysteretic behavior of bridge piers.

• 복식문화연구
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• 제31권1호
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• pp.34-52
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• 2023

In this study, text mining was conducted on the product names of skirts, pants, shirts/blouses, and dresses to analyze the characteristics of keywords appearing in online shopping product names. As a result of frequency analysis, the number of keywords that appeared 0.5% or more for each item was around 30, and the number of keywords that appeared 0.1% or more was around 150. The cumulative distribution rate of 150 terms was around 80%. Accordingly, information on 150 key terms was analyzed, from which item, clothing composition, and material information were the found to be the most important types of information (ranking in the top five of all items). In addition, fit and style information for skirts and pants and length information for skirts and dresses were also considered important information. Keywords representing clothing composition information were: banding, high waist, and split for skirts and pants; and V-neck, tie, long sleeves, and puff for shirts/blouses and dresses. It was possible to identify the current design characteristics preferred by consumers from this information. However, there were also problems with terminology that hindered the connection between sellers and consumers. The most common problems were the use of various terms with the same meaning and irregular use of Korean and English terms. However, as a result of using co-appearance frequency analysis, it can be interpreted that there is little intention for product exposure, so it is recommended to avoid it.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제27권4호
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• pp.246-257
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• 2024

Purpose: Administering early parenteral amino acids to very low birth weight (VLBW) premature infants (birth body weight [BBW]<1,500 g) is challenging due to factors such as holidays, cost, and access to sterile compounding facilities. Using advance-prepared parenteral nutrition (PN) may address this issue and should be evaluated for its safety and potential benefits. Methods: We extracted data from medical records collected between July 2015 and August 2019. VLBW infants received PN for at least seven days and were split into two groups: the traditional group (n=30), which initially received a glucose solution and then PN on workdays, and the pre-preparation group (n=16), which received advance-prepared PN immediately upon admission to the neonatal intensive care unit. Results: The median BBWs of the traditional and pre-preparation groups were 1,180.0 vs. 1,210.0 g. In the initial two days, the pre-preparation group had a significantly higher amino acid intake (2.23 and 2.24 g/kg/d) than the traditional group (0 and 1.78 g/kg/d). The pre-preparation group exhibited greater head circumference growth ratio relative to birth (7th day: 1.21% vs. -3.57%, p=0.014; 21st day: 7.71% vs. 3.31%, p=0.017). No significant differences in metabolic tolerance were observed. Conclusion: Advanced preparation of PN can be safely implemented in VLBW preterm infants, offering advantages such as early, higher amino acid intake and improved head circumference growth within the first 21 days post-birth. This strategy may serve as a viable alternative in settings where immediate provision of sterile compounding facilities is challenging.

• 한국사회복지학
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• 제60권1호
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• pp.211-231
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• 2008

본 연구에서는 65세 이상의 한국 노인을 대상으로 한국 노인의 성공적 노화 척도를 개발하였다. 성공적 노화 개념 추출을 위해 25명의 노인들에 대한 심층면접과 4개의 포커스 그룹을 통해 6개 영역의 성공적 노화 핵심 범주와 78개의 문항을 개발하였다. 이를 토대로 66문항의 일대일 면접설문지를 통해 수집된 표본 597부를 무선 분할하여 개발 표본 345부와 타당화 표본 252부의 분석을 통해 최종적으로 31문항으로 구성된 한국 노인의 성공적 노화 척도를 개발하였다. 이 척도는 '자율적 삶', '자기완성 지향', '적극적 인생 참여', '자녀에 대한 만족', '자기수용', 그리고 '타인수용' 등의 하위 요인으로 구성되어 있으며, Cronbach's $\alpha$값이 .903, 모형 적합도 지수 TLI가 .983, RMSEA가 .057로 만족할 만한 수준의 신뢰도와 타당도를 나타내었다. 또한 우리나라에서 노년기를 평가하는 데 있어서 가장 범용적인 척도로 간주되는 '노인의 삶의 질 척도'와 상관분석을 한 결과 r=.72의 높은 상관관계를 보여 공인타당도를 만족시켰다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1141-1141
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• 2001

The aim of the study was to evaluate the performance of 3 calibration methods, modified partial least squares (MPLS), local PLS (LOCAL) and artificial neural network (ANN) on the prediction of chemical composition of forages, using a large NIR database. The study used forage samples (n=25,977) from Australia, Europe (Belgium, Germany, Italy and Sweden) and North America (Canada and U.S.A) with information relative to moisture, crude protein and neutral detergent fibre content. The spectra of the samples were collected with 10 different Foss NIR Systems instruments, which were either standardized or not standardized to one master instrument. The spectra were trimmed to a wavelength range between 1100 and 2498 nm. Two data sets, one standardized (IVAL) and the other not standardized (SVAL) were used as independent validation sets, but 10% of both sets were omitted and kept for later expansion of the calibration database. The remaining samples were combined into one database (n=21,696), which was split into 75% calibration (CALBASE) and 25% validation (VALBASE). The chemical components in the 3 validation data sets were predicted with each model derived from CALBASE using the calibration database before and after it was expanded with 10% of the samples from IVAL and SVAL data sets. Calibration performance was evaluated using standard error of prediction corrected for bias (SEP(C)), bias, slope and R2. None of the models appeared to be consistently better across all validation sets. VALBASE was predicted well by all models, with smaller SEP(C) and bias values than for IVAL and SVAL. This was not surprising as VALBASE was selected from the calibration database and it had a sample population similar to CALBASE, whereas IVAL and SVAL were completely independent validation sets. In most cases, Local and ANN models, but not modified PLS, showed considerable improvement in the prediction of IVAL and SVAL after the calibration database had been expanded with the 10% samples of IVAL and SVAL reserved for calibration expansion. The effects of sample processing, instrument standardization and differences in reference procedure were partially confounded in the validation sets, so it was not possible to determine which factors were most important. Further work on the development of large databases must address the problems of standardization of instruments, harmonization and standardization of laboratory procedures and even more importantly, the definition of the database population.

• 한국콘텐츠학회논문지
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• 제12권1호
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• pp.48-58
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• 2012

다양한 센싱 모듈의 개발과 무선 통신 기술의 발달로 인해, 한정된 통신 능력과 제한된 연산 능력을 갖춘 다수의 센서 노드를 활용하여 무선 센서 네트워크를 구성하는 것이 가능하게 되었다. 이러한 센서 노드는 무인 환경이나 적지와 같은 환경에 배포되기 때문에 보안에 취약하다. 특히 실생활 응용에 사용될 때, 데이터가 노출되면 치명적인 피해를 입을 수 있기 때문에 보안에 대한 고려는 필수적이다. 하지만 기존 네트워크에서의 보안 기법은 센서 노드의 제한된 성능을 고려하지 않기 때문에, 무선 센서 네트워크에 적용하는 것은 한계가 있다. 이러한 점을 해결하기 위해, 본 논문에서는 무선 센서의 제한된 성능을 고려한 에너지 효율적인 보안 기법을 제안한다. 제안하는 기법은 원본 데이터의 해독을 어렵게 하기 위해 단-방향 해쉬 함수인 MD5를 기반으로 데이터를 변환 후, 분할하여 다중 경로를 통해 전송함으로써 보안성을 강화하는 것이 가능하다. 성능 평가 결과, 제안하는 기법은 기존 기법의 약 6%의 에너지만 소비하였다.

• 자원리싸이클링
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• 제26권2호
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• pp.46-55
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• 2017

본 연구에서는 레이저유도붕괴분광(Laser Induced Breakdown Spectroscopy, LIBS)을 이용하여 방사형 기저함수 신경회로망(Radial Basis Function Neural Networks, RBFNNs) 분류기 설계방법론을 개발하고 실제 폐소형가전제품의 플라스틱 분류 시스템에 적용하였다. ABS, PP, PS와 같은 검정색 플라스틱을 구별하기 위해, 지능형 알고리즘 중 하나인 방사형 기저함수 신경회로망 분류기를 설계하였다. 획득한 입력변수는 주성분 분석법(Principal Component Analysis, PCA)을 이용하여 축소시켰으며, 군집화기법 중 하나인 K-means 클러스터링 방법을 이용해 여러 그룹으로 분할하였다. 전체 데이터는 학습 데이터와 테스트 데이터를 4:1의 비율로 나누었으며, 제안된 분류기의 성능 및 신뢰도를 평가하기 위하여 5-FCV(5-Fold Cross Validation) 기법을 사용하였다. 입력변수와 클러스터의 개수가 각각 5개인 경우, 제안된 분류기의 분류 성능은 96.78%로 나타났다. 또한, 제안된 분류기는 다른 분류기들과 비교하였을 경우 분류 성능의 관점에서 우수성을 보여주었다.

• 한국정보과학회논문지:데이타베이스
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• 제35권1호
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• pp.17-28
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• 2008

최신 컴퓨터 시스템의 새로운 병목 현상이 메모리 접근에서 발생하고 있다. 메모리의 접근 속도를 줄이기 위해 캐시 메모리가 도입되었지만, 캐시 메모리는 원하는 데이타가 캐시에 옮겨져 있어야 메모리 접근 속도를 줄일 수 있다. 이를 해결하기 위해 기존의 T 트리를 개선한 CST 트리가 제안되었다. 하지만, CST 트리는 범위 검색 시, 불필요한 노드를 검색해야 한다는 단점이 있다. 본 논문은 캐시 효율적인 CST 트리의 장점을 가지며, 범위 검색이 가능하도록 하기 위해 연결 리스트로 각 노드를 연결한 $CST^+$ 트리를 제안하였으며, CST 및 $CSB^+$에 비해 $4{\sim}10$배의 성능 향상을 보였다. 또한, 메인 메모리 데이타베이스 시스템 장애 시, 빠른 데이타베이스 복구를 위해 인덱스의 빠른 재 구축은 전체 데이타 복구 성능에 있어 매우 중요한 부분이다. 이를 위해 본 논문은 병렬 삽입 기법을 제안하였다. 병렬 삽입은 노드 분할 오버헤드가 없으며, 데이타 복구 단계와 인덱스 구축 단계를 병렬로 수행할 수 있는 장점이 있다. 병렬 삽입은 순차 삽입 및 일괄 삽입에 비해 $2{\sim}11$배의 성능 향상을 보였다.