• 융합신호처리학회논문지
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• 제22권3호
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• pp.116-121
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• 2021

에너지를 절약하기 위해 고효율 히트펌프를 개발하기 위한 많은 연구가 이루어지고 있으며, 실외기 코일에 발생하는 서리가 발생하는 현상을 줄이거나 없애기 위한 연구도 동시에 이루어지고 있다. 계절과 관계없이 히트펌프의 실외기에 서리가 발생하지 않는 연구를 진행할 수 있도록 자연 상태와 동일한 조건에서 실험할 수 있는 곡선형 항온챔버를 구축하였다. 이러한 곡선형 항온챔버가 실험 장치로서 타당성을 갖추고 있는지 검증하기 위해 시뮬레이션을 하였다. CFD 조건은 곡선형 항온챔버 내에 위치한 실외기 앞의 직선형 덕트 길이를 덕트 관경의 1배, 5배, 10배, 15배로 하였다. 그 결과 덕트 관경의 10배 길이로 시뮬레이션했을 때 자연 상태와 가장 유사하다는 것을 알게 되었다.

• Computers and Concrete
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• 제34권2호
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• pp.247-265
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• 2024

Measuring the fracture toughness of concrete in laboratory settings is challenging due to various factors, such as complex sample preparation procedures, the requirement for precise instruments, potential sample failure, and the brittleness of the samples. Therefore, there is an urgent need to develop innovative and more effective tools to overcome these limitations. Supervised learning methods offer promising solutions. This study introduces seven machine learning algorithms for predicting concrete's effective fracture toughness (K-eff). The models were trained using 560 datasets obtained from the central straight notched Brazilian disc (CSNBD) test. The concrete samples used in the experiments contained micro silica and powdered stone, which are commonly used additives in the construction industry. The study considered six input parameters that affect concrete's K-eff, including concrete type, sample diameter, sample thickness, crack length, force, and angle of initial crack. All the algorithms demonstrated high accuracy on both the training and testing datasets, with R² values ranging from 0.9456 to 0.9999 and root mean squared error (RMSE) values ranging from 0.000004 to 0.009287. After evaluating their performance, the gated recurrent unit (GRU) algorithm showed the highest predictive accuracy. The ranking of the applied models, from highest to lowest performance in predicting the K-eff of concrete, was as follows: GRU, LSTM, RNN, SFL, ELM, LSSVM, and GEP. In conclusion, it is recommended to use supervised learning models, specifically GRU, for precise estimation of concrete's K-eff. This approach allows engineers to save significant time and costs associated with the CSNBD test. This research contributes to the field by introducing a reliable tool for accurately predicting the K-eff of concrete, enabling efficient decision-making in various engineering applications.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.318-318
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• 2022

Basil(Ocimum basilicum L.) is an annual herb that grows wild in hot and humid regions such as tropical Asia and Africa. This study was carried out for resource discovery, propagation, and DB construction of aromatic plants. In order to evaluate the genetic characteristics, 28 kinds of basil seeds were supplied from the Center for Genetic Resources. For basil characteristics, planting date, plant height, growth shape, leaf length, leaf shape, petiole color, petiole, stem color, flower color, after harvest, Ml length including roots, flower length, stem thickness and biological weight were measured. For anthocyanin analysis, only basil with purple color was selected, anthocyanins were extracted with 60% ethanol containing 1% citric acid, a standard quantitative curve was prepared with cyanidin-3-glucoside, and absorbance was measured at 525 nm. Basil planting started around June 16, and the flowering period lasted for a total of 18 days from July 19 to August 5. On August 6, when flowering was completed, morphological characteristics including flower color were measured at the site by an object. The measured basil plant length was 26.6-59.6 cm, leaf length 2.0-7.9 cm, leaf width 0.7-5.2 cm, and petiole 1.3-3.9 cm. The growth pattern of basil was generally straight, medium in shape. The color of the leaves was observed evenly by mixed green, purple, purple and green, and the recesses in the shape of the leaf were also conspicuously observed. A total of three basil flower colors were observed: white, light pink(149P 10P/84), and purple(37V 2.5RP 4/12). During the second growth survey after harvest, the total length including the basil roots is 26.7-52.0 cm, the flower length is 8.2-29.3cm, the stem thickness is 7.1-15.9mm, the number of stem nodes is 3-12 nodes, and the total weight of the basil was measured to be about 218-1540 g. There are a total of 16 types of basil expressed in purple, and the anthocyanin content was measured to be 73.74 ~ 380.72 mg/100g.

• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.104-108
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• 2014

Objectives: To evaluate the effect of passive ultrasonic agitation on the cleaning capacity of a hybrid instrumentation technique. Materials and Methods: Twenty mandibular incisors with mesiodistal-flattened root shape had their crowns sectioned at 1 mm from the cementoenamel junction. Instrumentation was initiated by catheterization with K-type files (Denstply Maillefer) #10, #15, and #20 at 3 mm from the working length. Cervical preparation was performed with Largo bur #1 (Dentsply Maillefer) followed by apical instrumentation with K-type files #15, #20 and #25, and finishing with ProTaper F2 file (Denstply Maillefer). All files were used up to the working length under irrigation with 1 mL of 2.5% sodium hypochlorite (Biodyn$\hat{a}$mica) at each instrument change. At the end of instrumentation, the roots were randomly separated into 2 groups (n = 10). All specimens received final irrigation with 1 mL of 2.5% sodium hypochlorite. The solution remained in the root canals in Group 1 for one minute; and ultrasonic agitation was performed in Group 2 for one minute using a straight tip inserted at 1 mm from working length. The specimens were processed histologically and the sections were analyzed under optic microscope (x64) to quantify debris present in the root canal. Results: The samples submitted to ultrasonic agitation (Group 2) presented significant decrease in the amount of debris in comparison with those of Group 1 (p < 0.05). Conclusions: The hybrid instrumentation technique associated with passive ultrasonic agitation promoted greater debris removal in the apical third of the root canals.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2092-2099
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• 2020

Many damages due to flow-accelerated corrosion and cracking have been observed during recent in-service inspections of nuclear power plants. To determine the operability or repair for damaged pipes, an integrity evaluation related to the damaged piping system should be performed by using already proven code and standards. One of them, the ASME Code Case is most popularly used to integrity assessment in nuclear power plants. However, the recent version of CC N-513 still recommends the simplified method which means a damaged elbow is assumed as an equivalent straight pipe. In addition, to enhance the accuracy integrity assessment in elbow, several previous studies recommend that the SIF and elastic COD values for an elbow with relatively large crack could be predicted by an interpolation technique. However, those estimates for elbow with relatively large crack might be derived to inaccurate results for crack growth analysis, such as for the allowable crack size and life estimation. Therefore, in this paper, the effect of crack length (0.3≤θ₁/π≤0.5) on SIF and elastic COD for elbow is systematically investigated. Then, for large crack in elbow, accurate estimates for SIF and elastic COD, which are widely used to assess the integrity of elbows, are proposed. Those proposed solutions are expected to be the technical basis for revisions of CC N-513-4 through the validation.

• 한국의상디자인학회지
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• 제13권4호
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• pp.79-91
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• 2011

This study divided school age by considering a change in the stage of body growth by age in elementary schoolgirls with the use of body scan data, and considered by comparing body size characteristics by school age. Elementary schoolgirls' body shape cannot be divided clearly. However, ages 7-10 were bound into the same group for the majority of girth, width, and thickness items. 7-8 years old, 9-10 years old, and 11-12 years old were bound into the same group in most items except ages 9 and 10 for the height item. Thus, significant difference was indicated between groups. Accordingly, this study divided the school age into three periods such as early stage(ages 7-8), middle stage(ages 9-10), and late stage(ages 11-12) in consideration of the stages for elementary schoolgirls' body-shape growth. As a result of analyzing body size according to division of school age, the higher school age leads to continuous growth. The notable growth was indicated especially in the middle stage and late stage. Examining centering on typical items related to the clothing construction, there was notable increase in waist thickness and hip thickness between early and middle stages and in height, weight, breast girth, waist circumference, back length, breast width, and waist width between middle and late stages. On the other hand, hip circumference, hip width, breast thickness, and length between shoulder edges were indicated to grow relatively and evenly among early, middle, and late stages. The lateral form was shown a clear difference in the forms of early, middle, and late stages in height and length of the whole body shape and in side thickness. The early and middle stages belong to body shape that abdomen is projected to be curved. The late stage showed right body shape which is straight and stable form in posture.

• 패션비즈니스
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• 제11권5호
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• pp.15-34
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• 2007

This study held a questionnaire for men in their 60s or above to analyze the market research of slacks, understand the characteristics of their lower body types, and provide the basic data for the slacks pattern-making fitting the body types of senior citizens. The findings are as follows. According to the results of a questionnaire, elderly men preferred order-made slacks for better fitness, but they favored ready-made owing to the matter of prices. In particular, the girth of waist was the most considered when purchasing. However, as most customers tended to repair slacks length and the waist part, their unsatisfaction with sizes was rather high. In body measurements, elderly men had higher variable coefficients or more individual differences in the items of thickness and angles than in those of height, length, and girth. Factor analysis revealed 5 front and 6 side factors. According to the results of front-side somatotype analysis, pimento-flat, trapezoid-flat, and bent-flat types require narrower pattern designs in down-upper width than the middle-aged class. In addition, pimento-protruded hip and straight-jar types need to be designed in the same amount as in the middle-aged class. Based on the questionnaire results, down-upper length as 1cm above real dimensions was analyzed to have superior sense of wearing.

• 한국어병학회지
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• 제9권1호
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• pp.15-19
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• 1996

피라미의 아가미로부터 검출된 Myxobolus sp.의 성숙 포자는 정면에서 특징적인 봉합융기가 없는 난형, 측면에서 직선적인 봉합면을 가진 레몬모양을 나타내었고 대칭적이며 표면이 평평한 포자각을 가졌다. 평균적인 포자의 길이, 넓이 및 두께는 각각 $10.4{\mu}m$, 7.7mm 및 $6.2{\mu}m$ 였고 평균적인 극낭의 길이와 넓이는 $4.6{\mu}m$와 $2.2{\mu}m$로 측정되었고 극낭속에 있는 극사는 6또는 7coil로 관찰되었으며 방출된 극사의 길이는 55-135㎛이었다. 한편으로 성숙 포자는 작은 극포간 돌기, 타원형의 요오드 친화성 공포 및 점막이 존재하는 것으로 관찰되었고 성숙 포자의 형태 및 크기는 M. cyprinicola Reuss, 1906과 가장 비슷한 것으로 나타났다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.265-271
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• 2000

Orifice meters and turbine meters are frequently used for measuring gas flow in gas industry. However, to insure the accuracy of the measurement, a certain length of the meter run at the upstream of the flow meter is required. The objective of this study is to analyze flow measurement errors of the orifice meter quantitatively for shorter lengths of the meter runs than those suggested in the standard manuals with variation of diameter ratio( $\beta$ ratio) and flow rate and also to analyze flow measurement errors of the turbine meter with and without straightener. The test results showed that the flow measurement errors of the orifice meter were inversely proportional to the diameter ratio. In other words, when the diameter ratio is 0.3 and 0.7, the measurement error is $-7.3\%$ and $-3.5\%$, respectively. the main reason of the measurement error is due to the swirl effect from the configuration of the meter run at the upstream of the flow meter. In case the length of the meter run is shorter than that suggested In the standard, the swirl effect is not removed completely and it affects the flow meter's performance. As mentioned above, the less the pipe diameter ratio, the mon the flow measurement error. It means that the swirl effect on the orifice meter increases as the $\beta$ ratio decreases.

• 한국의류산업학회지
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• 제11권5호
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• pp.753-763
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• 2009

The purpose of this study was to investigate the wearing situation and satisfaction of school uniforms with the middle and high school boys and girls, who have been in uniforms for one or more years. The subjects for the survey were a total of 560 from the 2nd and the 3rd grade of the middle school, and the 1st and the 2nd grade of the high school. The survey was performed with the questionnaire of 60 questions; 36 questions related to the actual status, such as the purchase, size, repair, and design of a school uniform, and 24 questions related to satisfaction. The results were as follows; 1. Regarding the school uniform purchase, middle school students attached importance to famous brand, while high school students valued design above everything else. The students confused with the school uniform sizing systems were 82.1 % and 72.5 % in middle and high school students. 2. 43% of middle school students and 34% of high school students had experiences of repairing their school uniforms. Regarding the reason for repair, the size misfit was the highest. Boys preferred a single breasted boxy jacket with middle hip line length, and straight trousers, and girls preferred a fitted jacket of waist line length, and flare skirt of the knee line length. 3. School uniform satisfaction score showed that students were not satisfied with their school uniforms so much. Middle school students had significantly lower satisfaction about the design and psychological protection than high school students. Even though high school students showed lower satisfaction about the price and the care of school uniforms, there were no significant differences between them.