• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.303-312
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• 2003

This paper suggests a fuzzy expert system for fault diagnosis of rotating machinery, based on modulated databases. In the proposed system, alarm and trip levels are set based on ISO, considering operating condition, machinery type and maintenance history. Input signals for diagnosis, such as sub- and super-harmonic components of vibration and mean value, are normalized from 0 to 1 under the threshold level and otherwise equal to one so that chronic faults slightly below the threshold level can be monitored. The database for diagnosis consists of two modules: the well-known Sohre's chart module and if-then type rules. The Sohre's chart is utilized for the most common problems of high-speed turbomachinery, while the rule-based module, which was collected from many papers and reports, is for diagnosing peculiar faults according to the type of machinery. To infer the results from two modules, a fuzzy operation of Yager sum was adopted. Using a simulator constructed in laboratory, experimental verification was performed for the cases of resonance and housing looseness which were intended. The experimental results show that the proposed fuzzy expert system has feasibility in practical diagnosis of rotating machinery.

• 대한토목학회논문집
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• 제29권5B호
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• pp.397-408
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• 2009

본 연구에서는 다지점의 일단위 강수량을 동시에 모의할 수 있는 추계학적 강수모의모형을 제시하였다. 각 지점의 강수발생은 무강수 기간에 대해 고차를 허용하는 혼합차수 마코프 모형을 이용하였으며, 강수량은 Anscombe 잔차와 감마분포를 이용하여 모의하였다. 다지점에 대한 강수발생과 강수량의 공간적 상관관계는, 상관관계를 가진 랜덤자료를 생성하여 재현하였다. 구축된 강수모의모형을 이용하여 우리나라 중부지역에 위치한 17개 관측지점의 강수량을 모의하고 모의정확성을 검토 하였다. 검증에 필요한 통계값들은 50번의 반복실행에 의해 생성된 강수량 시계열로부터 추정하여 제시하였다. 검토결과, 강수모의모형이 관측강수의 강수일수, 강수 지속기간, 무강수 지속기간, 강수일의 평균강수량과 표준편차 등을 비교적 잘 모의 하였다. 최대 강수 지속일과 무강수 지속일의 50번 반복실행의 평균값의 RMSE는 관측자료 평균값의 약 23% 정도, 100년 빈도와 200년빈도의 강수량의 RMSE는 관측자료 평균값의 약 17% 정도에 달하는 것으로 확인되었다. 강우발생과 강우량에 대한 공간적 상관관계는 비교적 정확히 재현하고 있음을 확인하였다.

• The Journal of Advanced Prosthodontics
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• 제7권3호
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• pp.224-232
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• 2015

PURPOSE. The purpose of this study was to find out the effect of immediate dentin sealing (IDS) on bond strength of ceramic restoration under various thermocycling periods with DBA (dentin bonding agent system). MATERIALS AND METHODS. Fifty freshly extracted human mandibular third molars were divided into 5 groups (1 control and 4 experimental groups) of 10 teeth. We removed enamel layer of sound teeth and embedded them which will proceed to be IDS, using All Bond II. A thermocycling was applied to experimental groups for 1, 2, 7, 14 days respectively and was not applied to control group. IPS Empress II for ceramic was acid-etched with ceramic etchant (9.5% HF) and silane was applied. Each ceramic disc was bonded to specimens with Duo-link, dual curable resin cement by means of light curing for 100 seconds. After the cementation procedures, shear bond strength measurement and SEM analysis of the fractured surface were done. The data were analyzed with a one-way ANOVA and Tukey multiple comparison test (${\alpha}$=.05). RESULTS. There were no statistically significant differences between 4 experimental groups and control group, however the mean value started to decrease in group 7d, and group 14d showed the lowest mean bond strength in all groups. Also, group 7d and 14d showed distinct exposed dentin and collapsed hybrid layer was observed in SEM analysis. CONCLUSION. In the present study, it can be concluded that ceramic restorations like a laminate veneer restoration should be bonded using resin cement within one week after IDS procedure.

• 한국연초학회지
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• 제21권1호
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• pp.82-88
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• 1999

The present study was conducted to compare the relative efficiency of two different haploid breeding methods in tobacco varietal development. A single FI hybrid plant from cross of two flue-cured cultivars of Nicotiana tabacum L., Bright Yellow4(BY4) and NC95, was used to develop the 30 anther derived dihaploid (ADH) lines and maternally-derived dihaploid (MDH) lines utilizing Nicotiana africana, respectively. As compared with mid-parent, mean of ADH lines showed increase in number of leaves, delay in days to flower and narrow in width of leaf. However, no significant differences in the other investigated characters were recognized. MDH lines also showed narrow width of leaf, while no significant differences in the other characters were observed. The variations of the investigated characters were generally greater in ADH than MDH lines. MDH lines had higher height of plant and shorter days to flower than ADH lines, while the other characters did not show remarkable differences. The degree of heritability for each of the characters observed between ADH and MDH was almost the same. The characters showing high heritability value were height of plant, number of leaves, days to flower, and yield, while those showing relatively low value were length of leaf, width of leaf, and total alkaloid content. Predicted gains from selection for increased yield were calculated for both populations(ADH, MDH) and correlated responses associated with selection for yield were estimated. Height of plant, width of leaf, days to flower, and concentration of reduceing sugar would be expected to improve with selection for yield much faster in the MDH population than in the ADH.

• 원예과학기술지
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• 제35권2호
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• pp.276-286
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• 2017

Licorice, a traditional Korean medicinal plant, is recognized for its main active ingredient, glycyrrhizin. The level of glycyrrhizin in Chinese licorice (Glycyrrhiza uralensis) is lower than the reference level (2.5%) set by the Korean Pharmacopoeia, reducing its value as a medicinal herb. In this study, we aimed to overcome this problem by generating an interspecific licorice hybrid by crossing European licorice (G. glabra) with Chinese licorice, resulting in the production of 32 $F_1$ lines. A comparison of genetic traits revealed variations in glycyrrhizin content among lines, ranging from 1.5 to 5.6%, with a mean value of 3.2%; these values are higher than that of the parental plants. Additionally, 25 lines (78.1%) had a glycyrrhizin content greater than 2.5%, which is higher than the reference level set by the Korean Pharmacopoeia. Four of these lines had glycyrrhizin levels higher than the WHO recommended level of 4.0%. A comparison of phenotypic characteristics showed that the leaves of the hybrids possessed all of the characteristics of European and Chinese licorice; however, the stems of most hybrids had characteristics of European licorice. Finally, we determined the genetic distances of 34 samples of Glycyrrhiza plants (parents, 32 $F_1$ lines) by random amplified polymorphic DNA (RAPD); the $F_1$ lines showed a close genetic distance. We plan to develop to a cultivar using five of these lines (glycyrrhizin content < 4.0%).

• 농업과학연구
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• 제46권1호
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• pp.183-194
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• 2019

Adulteration of argan oil with some other cheaper oils with similar chemical compositions has resulted in increasing demands for authenticity assurance and quality control. Fast and simple analytical techniques are thus needed for authenticity analysis of high-priced argan oil. Raman spectroscopy is a potent technique and has been extensively used for quality control and safety determination for food products In this study, Raman spectroscopy in combination with a net analyte signal (NAS)-based methodology, i.e., hybrid linear analysis method developed by Goicoechea and Olivieri in 1999 (HLA/GO), was used to predict the different concentrations of olive oil (0 - 20%) added to argan oil. Raman spectra of 90 samples were collected in a spectral range of $400-400cm^{-1}$, and calibration and validation sets were designed to evaluate the performance of the multivariate method. The results revealed a high coefficient of determination ($R^2$) value of 0.98 and a low root-mean-square error (RMSE) value of 0.41% for the calibration set, and an $R^2$ of 0.97 and RMSE of 0.36% for the validation set. Additionally, the figures of merit such as sensitivity, selectivity, limit of detection, and limit of quantification were used for further validation. The high $R^2$ and low RMSE values validate the detection ability and accuracy of the developed method and demonstrate its potential for quantitative determination of oil adulteration.

• 한국지리정보학회지
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• 제23권4호
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• pp.234-252
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• 2020

계측기기만을 이용한 현장 상황대응의 재래적 방식에서 벗어나 온라인 '첨단기술(Hi-Technology)'과 오프라인의 '직관적 경험(Hi-Experience)'을 융합한 하이브리드(Hybrid) 재해관리 기법의 유효성을 검증하였다. 이를 위해 대상 현장에 매설된 상시 계측기 GNSS(RTK) 5대를 지상기준점(Ground Control Point, GCP)으로 사용하였다. 또한, 인근 지점에 크기 불변 특징점(Scale Invariant Feature Transform, SIFT) 4곳을 추출하여 검사점(Control Point, CP)으로 활용하였다. 이를 통해 현장 실측치와 드론기반 3차원 측정 결과치와의 정확도를 각 좌표값의 차이의 평균제곱근오차(Root Mean Square Error)를 이용하여 분석하였다. 결과적으로 드론에 의해 획득된 3차원 수치 모델을 정밀하게 후처리 분석함으로써 피사체의 모든 지형지물이 변위추적의 객체로 활용할 수 있음을 확인할 수 있었다. 포인트 클라우드(Point cloud) 기반의 3-D 수치 영상은 현장 그대로의 모습을 초실감, 고정도 가시화 함으로서 직관적인 경험에 공감할 수 있는 친화적인 솔루션을 제공하며, 단순 신호처리 기반의 계측기기 하드웨어 중심의 재해관리를 탈피해 인명피해/예산 절감 등 비탈면 유지관리에 최적의 플랫폼을 제공할 수 있을 것으로 판단된다. 특히, 특정 위치에 설치된 특정지점(Pin-point) 센서에 의존한 국지적인 정보의 한계를 뛰어넘어 기술생산 중심에서 재난관리의 중심으로 신속하게 전환될 수 있는 매개체가 될 것으로 기대한다.

• 지능정보연구
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• 제27권2호
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• pp.1-15
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• 2021

추천시스템은 사용자의 기호를 파악하여 물품 구매 결정을 도와주는 역할을 할 뿐만 아니라, 비즈니스 전략의 관점에서도 중요한 역할을 하기에 많은 기업과 기관에서 관심을 갖고 있다. 최근에는 다양한 추천시스템 연구 중에서도 NLP와 딥러닝 등을 결합한 하이브리드 추천시스템 연구가 증가하고 있다. NLP를 이용한 감성분석은 사용자 리뷰 데이터가 증가함에 따라 2000년대 중반부터 활용되기 시작하였지만, 기계학습 기반 텍스트 분류를 통해서는 텍스트의 특성을 완전히 고려하기 어렵기 때문에 리뷰의 정보를 식별하기 어려운 단점을 갖고 있다. 본 연구에서는 기계학습의 단점을 보완하기 위하여 BERT 기반 감성분석을 활용한 추천시스템을 제안하고자 한다. 비교 모형은 Naive-CF(collaborative filtering), SVD(singular value decomposition)-CF, MF(matrix factorization)-CF, BPR-MF(Bayesian personalized ranking matrix factorization)-CF, LSTM, CNN-LSTM, GRU(Gated Recurrent Units)를 기반으로 하는 추천 모형이며, 실제 데이터에 대한 분석 결과, BERT를 기반으로 하는 추천시스템의 성과가 가장 우수한 것으로 나타났다.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.310-321
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• 1999

In this in vitro study, confocal laser scanning microscopic morphology of dentin-resin interface and its relationship to shear bond strength were investigated after the exposed dentin surfaces were treated with 3 different kinds of dentin adhesive systems[three-step; Scotchbond Multi-Purpose Plus(SMPP), self-priming bonding resin; Single Bond(SB), self-etching primer; Clearfil Liner Bond 2(LB2)]. 52 extracted human molar teeth without caries and/or restorations. The experimental teeth were randomly divided into three groups of seventeen teeth each. In five teeth of each group, class V cavities(depth: 1.5mm) with 900 cavosurface angles were prepared at the cementoenamel junction on buccal and lingual surfaces. Bonding resins of each dentin adhesive system were mixed with rhodamine B. Primer of SMPP was mixed with fluorescein. In group 1. the exposed dentin was conditioned with etchant, applied with above primer and bonding resin of SMPP. In group 2, with etchant and self-priming bonding agent of SB. In group 3, with self-etching primer and bonding agent of LB2. After treatment with dentin adhesive systems, composite resin were applied and photocured. The experimental teeth were cut longitudinally through the center line of restoration and grounded so that about $90{\mu}m$-thick wafers of buccolingually orientated dentin were obtained. And, $70{\sim}80{\mu}m$-thick wafers sectioned horizontally, thus presenting a dentinal tubules at 900 to the cut surface of a remaining tooth, were obtained. Primer of SMPP mixed with rhodamine B was applied to these wafers. Confocal laser scanning microscopic investigations of these wafers were done within of 24 hours after treatment. To measure shear bond strength, the remaining twelve teeth of each group were grounded horizontally below the dentinoenamel junction, so that no enamel remained. After applying dentin adhesive systems on the dentin surface, composite was applied in the shape of cylinder. The cylinder was 5mm in diameter, and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. It was concluded as follows ; 1. Hybrid layer of SMPP(mean: $4.56{\mu}m$) was thicker than that of any other groups. This value was not statistically significant thicker than that of SB(mean: $3.41{\mu}m$, p>0.05), and significant thicker than that of LB2(mean: $1.56{\mu}m$, p<0.05). There was a statistical difference between SB and LB2(p<0.05). 2. Although there were variations in the length of resin tag even in a sample, and in a group, most samples in SMPP and SB showed resin tags extending above $20{\mu}m$. But samples in LB2 showed resin tags of $10{\mu}m$ at best. 3. Besides primer's infiltration into demineralized peritubular dentin and dentinal tubules, fluorophore of primer was detected in the lateral branches of dentinal tubules. 4. All groups demonstrated statistically significant differences from one another(p<0.05), with shear bond strengths given in descending order as follows: SMPP(18.3MPa), SB(16.0MPa) and LB2(12.4MPa). 5. LB2 having thinnest hybrid layer($1.56{\mu}m$) showed the lowest shear bond strength(12.4MPa).

• 한국초지조사료학회지
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• 제31권4호
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• pp.371-382
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• 2011

연구는 표고 760 m 지역인 강원도 평창군 대관령면에 위치한 국립축산과학원 한우시험장에서 2009년부터 2010년까지 2년간 기후조건과 사일리지용 옥수수의 생육특성과 생산량의 관계를 검토하였다. 파종에서 수확기까지의 평균 최저기온은 2009년에 $12.29^{\circ}C$, 2010년에는 $14.30^{\circ}C$ 였고 평균최고기온은 2009년 $21.66^{\circ}C$, 2010년 $23.48^{\circ}C$ 였다. 평균기온은 2009년 $16.85^{\circ}C$, 2010년 $18.55^{\circ}C$ 였다. 일조시간은 2009년도 711.3시간, 2010년 663.8시간이었고 강수량은 2009년 893.8 mm, 2010년 752.1 mm였다. 초기 생육은 2009년에 광평옥, 강다옥, 청안옥, 청사옥, 평안옥 모두 1.2로 나타나 초기생육이 양호하였고 2010년에는 평안옥은 1.3으로 양호하였으나 다른 네 품종은 2.4~3.0으로 2009년보다 양호하지 못하였다. 착수고는 모든 품종의 평균값에서는 2009년도 85.8cm, 2010년도 105cm로 높은 유의차가 인정되었다(p<0.001). 줄기의 직경도 모든 품종에서 2010년도가 굵었으며 년도 간 유의차가 인정되었고(p<0.01, p<0.001), 모든 품종의 평균값에서도 높은 유의차가 나타났다(p<0.001). 초장은 2009년에는 200 cm, 2010년에는 258 cm로 높은 유의차가 인정되었다(p<0.001). 출사에 소요된 평균기간이 2009년에는 103.8일, 2010년에는 90일로 연도에 따른 높은 상관관계가(p<0.001) 나타났다. 2009년도와 2010년도에 모든 품종에서 도복은 일어나지 않았으며 병충해의 피해도 나타나지 않았다. 암이삭 비율은 모든 품종의 평균 비율은 2009년 23.4%, 2010년 52.1%로 두 배 이상의 차이가 나타났다. 모든 품종의 평균 생초수량은 2009년에 54,611 kg/ha, 2010년도에 78,733 kg/ha으로 나타났다(p<0.001). 건물생산량은 2009년 보다 평균기온이 높은 2010년에 많았다. 가소화영양소총량 비율은 강다옥과 청안옥은 2009년도에 높았으며 청사옥과 평안옥은 2010년도에 높게 나타났다. 조단백질의 함량은 모든 품종에서 2009년 보다 2010년에 더 많은 함량을 나타내었다. 본 연구 결과 기온과 생육특성 및 수량과의 관계를 보았을 때 고랭지에서는 광평옥과 평안옥이 재배하기 적합한 품종이었다.