• 한국해양공학회지
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• 제37권1호
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• pp.8-19
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• 2023

In recent years, modular-type floating islands have been considered as a promising option for future ocean space utilization. A modular floating island consists of a number of standardized pontoon-type modules and connectors between them. In this study, the motion responses of a modular floating island in waves was investigated based on frequency-domain numerical analysis. The numerical method is based on the potential flow theory and adopts a higher-order boundary element method with Green's function. First, motion RAOs were directly compared with the model test data by reference to validate the present numerical method. Then, numerical investigations were conducted to analyze the motion characteristics of the floating island by considering various modules shapes and arrangements. It was found that motion responses were reduced in a single central module compared to when divided central modules were used. Finally, the effect of modular arrangement on the motion responses in irregular waves was discussed. It was confirmed that multiple-layer outer modules are more effective in calming the central module than using single-layer outer modules, except under very long period conditions.

• 스마트미디어저널
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• 제11권2호
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• pp.53-62
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• 2022

산업화 이후 가속화된 지구 온난화 현상으로 인해 기존환경 변화 및 이상기후 발생 빈도가 증가하고 있다. 농업은 기후변화에 매우 민감한 분야의 산업으로 지구 온난화는 작물의 생산량을 감소시키고 재배 지역이 변하는 등의 문제를 발생시킨다. 또한, 환경 변화는 작물의 생육 시기를 불규칙하게 만들어 숙련된 농사꾼들도 작물의 생육단계를 쉽게 추정할 수 없도록 만들어 여러 문제를 발생시킨다. 이에 본 논문에서는 작물의 생육단계를 추정하기 위한 CNN(Convolution Neural Network) 모델을 제안한다. 제안한 모델은 ResNet의 Pooling Layer를 수정한 모델로 ResNet, DenseNet 모델의 생육단계 추정보다 높은 성능 결과를 확인하였다.

• 한국수산과학회지
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• 제34권1호
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• pp.43-50
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• 2001

규칙파, 불규칙파 및 파랑과 흐름이 공존하는 상태에서 프레임에 우리형 그물을 부착하여 구성되어 있는 가두리 시설의 운동특성을 분석하기 위하여 정사각형 및 원형 구조의 가두리 시설을 대상으로 예인 수조에서 수리 모형실험을 실시하였으며, 규칙파중 운동 특성은 선형 포텐셜 이론에 의한 수치 해석의 그것과 비교하였다. 그 결과는 다음과 같이 요약할 수 있다. 1) 규칙파중 모형 가두리 시설의 상하 및 종 동요는 전후 동요와는 달리 그물의 영향을 거의 받지 않았으므로 이 시설물의운동 특성중 가장 중요한 상하 동요를 해석하는 경우에는 그물을 제외하고 프레임만을 고려해도 된다는 것을 확인하였다. 2) 불규칙파중 및 파랑과 흐름이 공존하는 상태에서 모형 가두리 시설의 운동 특성은 입사파 주기의 2배 되는 고주파수에서 시설물의 고유 주기 등에 의해 동적 운동의 peak frequency가 나타남으로써 비선형 즉, 2nd order harmonic 성분이 존재하였다 3) 파동 및 흐름장에서 동요 특성이 정사각형에 비해 비교적 작게 나타난 원형이 파도, 조류 등 환경 조건이 거친 해역에 보다 적합한 것으로 판단되었다.

• 가족자원경영과 정책
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• 제19권2호
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• pp.1-26
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• 2015

The purpose of this study was to analyze the quality of life (QoL) of elderly women and the effect of social support on their QoL. The data were used 'urvey on the Elderly in 2011', which was held from 'Ministry of Health & Welfare' and 'Korea Institute for Health and Social Affairs'. Among the total 15,146 respondents, 3,880 of elderly women whose age was over 65, and who did not live together with their married children were included in the analysis. Multiple regression analysis and path analysis were used to analyze the research model. The findings were as follows. First, from the fact that the elderly women showed the highest mean in 'contact frequency with friends' among social support, it seemed that the elderly women contacted their friends more than their children in their old age. Among the support types from their children, elderly women received emotional support, physical support, instrumental support in order and irregular cash as a way of economic support. Second, from the regression results, the most critical factor that affected the QoL of elderly women was 'subjective physical condition level' and 'subjective standard of living' comes next. Third, the most important factor was 'subjective standard of living' from path analysis results, and 'subjective physical condition level' and 'total amount of annual income' in order. Also, social supports such as 'phone call contact frequency with children', 'emotional support from children', phone call contact frequency with relatives', 'phone call contact frequency with friends' positively affected the QoL of elderly women. Therefore, raising social supports from children, relatives, and friends positively contributes to improve the QoL of elderly women directly and indirectly. The results show that social supporters, which is a part of the structural aspects of social support, and types of social support, which lies in functional aspects, directly affect QoL of the elderly women and turn out to be factors that improve the QoL as mediating variables. It is concluded that the social supports can be the most important resources that make up declining personal and social resources in old age and maintain the QoL of elderly women.

• 펄프종이기술
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• 제47권4호
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• pp.177-186
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• 2015

Until Mandelbrot introduced the concept of fractal geometry and fractal dimension in early 1970s, it has been generally considered that the geometry of nature should be too complex and irregular to describe analytically or mathematically. Here fractal dimension indicates a non-integer number such as 0.5, 1.5, or 2.5 instead of only integers used in the traditional Euclidean geometry, i.e., 0 for point, 1 for line, 2 for area, and 3 for volume. Since his pioneering work on fractal geometry, the geometry of nature has been found fractal. Mandelbrot introduced the concept of fractal geometry. For example, fractal geometry has been found in mountains, coastlines, clouds, lightning, earthquakes, turbulence, trees and plants. Even human organs are found to be fractal. This suggests that the fractal geometry should be the law for Nature rather than the exception. Fractal geometry has a hierarchical structure consisting of the elements having the same shape, but the different sizes from the largest to the smallest. Thus, fractal geometry can be characterized by the similarity and hierarchical structure. A process requires driving energy to proceed. Otherwise, the process would stop. A hierarchical structure is considered ideal to generate such driving force. This explains why natural process or phenomena such as lightning, thunderstorm, earth quakes, and turbulence has fractal geometry. It would not be surprising to find that even the human organs such as the brain, the lung, and the circulatory system have fractal geometry. Until now, a normal frequency distribution (or Gaussian frequency distribution) has been commonly used to describe frequencies of an object. However, a log-normal frequency distribution has been most frequently found in natural phenomena and chemical processes such as corrosion and coagulation. It can be mathematically shown that if an object has a log-normal frequency distribution, it has fractal geometry. In other words, these two go hand in hand. Lastly, applying fractal principles is discussed, focusing on pulp and paper industry. The principles should be applicable to characterizing surface roughness, particle size distributions, and formation. They should be also applicable to wet-end chemistry for ideal mixing, felt and fabric design for papermaking process, dewatering, drying, creping, and post-converting such as laminating, embossing, and printing.

• 한국지진공학회논문집
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• 제22권3호
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• pp.175-184
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• 2018

In this paper, comparative analysis of the 9.12 Gyeongju and 11.15 Pohang earthquakes was conducted in order to provide probable explanations and reasons for the damage observed in the 11.15 Pohang earthquake from both earthquake and structural engineering perspectives. The damage potentials like Arias intensity, effective peak ground acceleration, etc observed in the 11.15 Pohang earthquake were generally weaker than those of the 9.12 Gyeongju earthquake. However, in contrast to the high-frequency dominant nature of the 9.12 Gyeongju earthquake records, the spectral power of PHA2 record observed in the soft soil site was highly concentrated around 2Hz. The base shear around 2 Hz frequency was as high as 40% building weight. This frequency band is very close to the fundamental frequency of the piloti-type buildings severely damaged in the northern part of Pohang. Unfortunately, in addition to inherent vertical irregularity, most of the damaged piloti-type buildings had plan irregularity as well and were non-seismic. All these contributed to the fatal damage. Inelastic dynamic analysis indicated that PHA2 record demands system ductility capacity of 3.5 for a structure with a fundamental period of 0.5 sec and yield base shear strength of 10% building weight. The system ductility level of 3.5 seems very difficult to be achievable in non-seismic brittle piloti-type buildings. The soil profile of the PHA2 site was inversely estimated based on deconvolution technique and trial-error procedure with utilizing available records measured at several rock sites during the 11.15 Pohang earthquake. The soil profile estimated was very typical of soil class D, implying significant soil amplification in the 11.15 Pohang earthquake. The 11.15 Pohang earthquake gave us the expensive lesson that near-collapse damage to irregular and brittle buildings is highly possible when soil is soft and epicenter is close, although the earthquake magnitude is just minor to moderate (M 5+).

• 한국측량학회지
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• 제33권5호
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• pp.353-361
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• 2015

매년 적조가 발생하여 양식어민들에게 막대한 피해를 주고 있으며 발생해역도 남해안을 중심으로 발생되던 패턴에서 전국 연안 해역으로 확대되는 추이를 보이고 있다. 광활한 해양에서 발생되는 적조를 효과적으로 모니터링하기 위해 2010년에 발사된 천리안 위성의 GOCI(Geostationary Ocean Color Imager)영상을 이용한 적조 탐지기술 개발에 관심이 모아지고 있다. 본 연구에서는 남해안 해역에 대해 최근 3년간(2012, 2013, 2014년) 관측된 천리안 GOCI영상을 이용하여 적조해역을 탐지하고 탐지된 해역에 대한 적조발생빈도와 밀도를 분석하였다. 그 결과 3년간 남해안을 대상으로 적조 발생 해역을 추출하고 중첩분석과 밀도분석을 통하여 적조우심해역을 추출하여 제시하였다. 또한 연도별 적조발생 경향은 2012년에 적조 발생규모가 작고 산발적으로 발생하였고, 2013년은 적조 발생해역이 광범위하게 분포하면서 공간적 밀집도도 높게 나타났으며, 2014년의 경우에는 소규모의 적조가 산발적으로 발생하였다. 이처럼 연도별 적조발생의 공간적 분포패턴은 불규칙한 특징을 보였으며 다양하게 변화되고 있음을 알 수 있었다. 하지만 적조발생빈도를 기반으로 핫스팟을 분석한 결과 특정 해역에서는 발생빈도가 꾸준히 증가되고 있어서 천리안 GOCI 영상과 같은 위성영상모니터링 기술을 이용하여 지속적으로 모니터링을 실시함으로써 적조의 움직임을 정확히 예측할 수 있고 이에 따른 방재계획을 체계적으로 수립할 수 있다고 판단된다.

• 부모자녀건강학회지
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• 제3권2호
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• pp.25-40
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• 2000

The purpose of this study is to identify the sleep/activity patterns of neonates and to provide a baseline data in developing an effective maternal-child nursing intervention strategies. The subjects of this study were 57 normal newborn babies from birth to 4 weeks of age, who visited the Postpartum Care Center and two General Hospitals and One Local clinic in Taejon. The data were collected from October 28th, 1999 to April 28th, 2000. The instrument used in this study was NCASA developed by Barnard and validated by the Academic Society of Parent-Child Health. The data were analyzed with the SPSS PC+ 7.5 for window program using means, standard deviation, one-way ANOVA. The results of this study were as follows: 1. The mean amount of daytime sleep was 7.45 hours, nighttime sleep was 4.27 hours, and the total daily sleep was 11.72 hours. The mean amount of longest sleep period was 4.32 hours. The mean regularity of daytime sleep was 35.55%, the nighttime sleep was 44.82%, and the total daily sleep was 39.02%. The mean frequency of nighttime awakenings was 2.44 times. 2. The mean amount of daytime awake periods was 8.54 hours, the nighttime awake periods was 3.72 hours, and the daily total awake periods was 12.27 hours. The mean amount of the longest awake period was 3.98 hours. 3. The mean frequency of daytime feeding was 5.18 times, the nighttime feeding was 2.50 times, and the total daily feeding was 7.49. The mean of regularity of total daily feeding was 61.34%. 4. According to an analysis of sleep patterns based on newborn's age, there were some statistically significant differences noted in the following factors ; amount of nighttime sleep (F=7.65, p=.002), longest sleep period(F=5.84, P=.006). 5. According to an analysis of activity patterns based on newborn's age, there were some statistically significant differences noted in the following factors ; amount of nighttime activity (F=7.64, P=.002), longest activity period (F=4.34, P=.020), frequency of nighttime feeding(F=3.89, p=.029), frequency of total daily feeding(F=3.76, P=.033), and regularity of daily feeding(F=4.66, P=.016). In conclusion, the newborn baby slept more during the daytime than nighttime and more active during the daytime. And there were some irregular sleep/activity pattern noted during 1 to 2 weeks of newborn baby. The results of this study will contribute to maternal-child health nursing practice and nursing research, and provide an information to parents about what to expect their newborn baby.

• Nutrition Research and Practice
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• 제15권3호
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• pp.355-366
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• 2021

BACKGROUND/OBJECTIVES: The study was performed to investigate health-related lifestyle, dietary habits, and depression according to exercise frequency to understand complex factors that affect effective health management. Thus, exercise frequency, health-related lifestyle, dietary habits, and depression were evaluated in college students in Seoul and Gyeonggi-do areas. SUBJECTS/METHODS: A survey was conducted on college students, aged 19-29, in Seoul and Gyeonggi-do areas from May 13 to May 31, 2020. A total of 594 questionnaires were collected and 566 (269 from males, 297 from females) were statistically analyzed, except 28 with incomplete responses. Collected data were analyzed using SPSS WIN 21.0 program. RESULTS: The sex distribution of the 3 groups according to exercise frequency was significantly different; the ratio of males in over 3 times/week group was significantly higher than those in 1-2 times/week group and no-exercise group (P < 0.001). The height (P < 0.001), weight (P < 0.001), and body mass index (P < 0.05) were significantly higher in over 3 times/week group compared to no-exercise group. The ratio of subjects who answered 'good' or 'very good' for subjective health condition was significantly high in the order of 'over 3 times/week' group (59.1%), '1-2 times/week' group (34.5%), and 'no-exercise' group (25.0%) (P < 0.001). The ratio for meal regularity was high as 56.6% in 'over 3 times/week' group and the ratio for irregular meals was significantly higher in 'no-exercise' group (67.2%) and '1-2 times/week' group (54.9%) (P < 0.001). Among questions on dietary habits, 'Eat meat, fish, egg or beans' (P < 0.01) and 'Eat fruit' (P < 0.01) were significantly higher in 'over 3 times/week' group compared to 'no-exercise' group. 'Drink more than 2 liters of water' (P < 0.001) was 0.70 in 'over 3 times/week' group, which was significantly higher than 0.54 in '1-2 times/week' group and 0.38 in 'no-exercise' group. Moderate depression and severe depression that need treatments were significantly lower in 'over 3 times/week' group (18.7%) compared to '1-2 times/week' group (26.0%) and 'no-exercise' group (29.7%) (P < 0.05). CONCLUSIONS: It is considered that combined intervention for exercise habits, proper dietary habits, and depression management is needed for effective health management.

• 한국동물학회지
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• 제12권3호
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• pp.85-93
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• 1969

5-AU에 의해 同時分裂促進된 사람의 胎兒 賢臟細胞를 材料로 steroid 에 의한 染色體 異常率 時間經過에 따른 染色體異常率, DNA 合成樣相을 調査한 結果는 다음과 같다. 1. 5-AU 處理區에서 細胞當 染色體 異常率은 0.131로 對照區에 比해 3倍 이상이나 된다. 또한 5-AU + progesterone 과 5-AU + testosterone 處理區에서는 細胞當 染色體異常率이 각각 0.340과 0.452이다. 2. 5-AU 處理區에서 異常染色體를 지니는 細胞는 0.8%로 時間變化에 무관하게 전체 其間에 걸쳐 존재한다. 5-AU + progesterone과 5-AU + testosterone 處理區에서는 2.2%, 4.3%의 異常染色體數가 觀察되고, 時間이 지남에 따라 增加한다. 또한 染色體 異常率은 5-AU + progesterone 處理區에서는 12時間과 18時間에 가장 높았고, 5-AU + testosterone 處理區에서는 時間變化에 따라 감소하고 5-AU 處理區에서는 유의한 차이가 없다. 3. 5-AU 는 標識分裂像의 出現頻度와 標識强度를 增加시키는데, 이는 5-AU에 의해 S-stage의 細胞가 축적되는 결과로 생각된다. 그러나 steroid는 標識分裂像의 出現頻度를 감소시키고 DNA 合成時期를 지연시키고 있다. 또한 性染色體의 DNA 合成樣相이 細胞週期의 각 段階에 따라 다르며, 이는 5-AU와 steroid의 二重處理로 DNA 合成時期를 不規則하게 만든 때문이다.