• Therapeutic Science for Rehabilitation
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• v.13 no.1
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• pp.35-47
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• 2024

Objective : This study aimed to investigate the association between lifestyle factors and risk of frailty and depressive symptoms among older South Korean adults. Methods : This study included 10,072 individuals aged 65 or older from the 2017 National Survey of Older Koreans, a cohort of community-dwelling older South Koreans. The following lifestyle factors were assessed: physical activity, nutrition management (NM), and leisure/social activity participation (AP). Frailty was measured using the frail scale and depressive symptoms were measured using the Geriatric Depression Scale. Logistic regression analyses were performed to determine the odds ratios. Results : All lifestyle factors were associated with the risk of frailty and depressive symptoms in the study population. Regular exercise (≥3 times/wk, odds ratio [OR] = 0.59, 95% confidence interval [95% CI] = 0.52~0.91; OR = 0.66, 95% CI = 0.59~0.75), active NM (OR = 0.86, 95% CI = 0.80~0.91; OR = 0.81, 95% CI = 0.76~0.86), leisure AP (OR = 0.79, 95% CI = 0.74~0.84; OR = 0.71, 95% CI = 0.66~0.77) and social AP (OR = 0.92, 95% CI = 0.88~0.96; OR = 0.82, 95% CI = 0.78~0.87) were correlated with lower odds ratios of frailty and depressive symptoms. Conclusion : Adopting a healthier lifestyle characterized by regular exercise, balanced nutrition, and active engagement in various activities can effectively reduce the risk of frailty and depressive symptoms among the older population. Ultimately, this study emphasized the essential role of lifestyle choices in promoting the physical and mental well-being of older adults.

• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.1-8
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• 2024

Persistent droughts due to climate change will intensify water shortage problems in Korea. According to the 1st National Water Management Plan, the shortage of domestic and industrial waters is projected to be 0.07 billion m³/year under a 50-year drought event. A long-term prediction of water demand is essential for effectively responding to water shortage problems. Unlike industrial water, which has a relatively constant monthly usage, domestic water is analyzed on monthly basis due to apparent monthly usage patterns. We analyzed monthly water usage patterns using water usage data from 2017 to 2021 in Chungcheong, South Korea. The monthly water usage rate was calculated by dividing monthly water usage by annual water usage. We also calculated the water distribution rate considering correlations between water usage rate and climate variables. The division method that divided the monthly water usage rate by monthly average temperature resulted in the smallest absolute error. Using the division method with average temperature, we calculated the water distribution rates for the Chungcheong region. Then we predicted future water usage rates in the Chungcheong region by multiplying the average temperature of the SSP5-8.5 scenario and the water distribution rate. As a result, the average of the maximum water usage rate increased from 1.16 to 1.29 and the average of the minimum water usage rate decreased from 0.86 to 0.84, and the first quartile decreased from 0.95 to 0.93 and the third quartile increased from 1.04 to 1.06. Therefore, it is expected that the variability in monthly water usage rates will increase in the future.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.229-241
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• 2024

With the advancement of big data processing technology using cloud platforms, access, processing, and analysis of large-volume data such as satellite imagery have recently been significantly improved. In this study, the Change Detection Method, a relatively simple technique for retrieving soil moisture, was applied to the backscattering coefficient values of pre-processed Sentinel-1 synthetic aperture radar (SAR) satellite imagery product based on Google Earth Engine (GEE), one of those platforms, to estimate the surface soil moisture for six observatories within the Yongdam Dam watershed in South Korea for the period of 2015 to 2023, as well as the watershed average. Subsequently, a correlation analysis was conducted between the estimated values and actual measurements, along with an examination of the applicability of GEE. The results revealed that the surface soil moisture estimated for small areas within the soil moisture observatories of the watershed exhibited low correlations ranging from 0.1 to 0.3 for both VH and VV polarizations, likely due to the inherent measurement accuracy of the SAR satellite imagery and variations in data characteristics. However, the surface soil moisture average, which was derived by extracting the average SAR backscattering coefficient values for the entire watershed area and applying moving averages to mitigate data uncertainties and variability, exhibited significantly improved results at the level of 0.5. The results obtained from estimating soil moisture using GEE demonstrate its utility despite limitations in directly conducting desired analyses due to preprocessed SAR data. However, the efficient processing of extensive satellite imagery data allows for the estimation and evaluation of soil moisture over broad ranges, such as long-term watershed averages. This highlights the effectiveness of GEE in handling vast satellite imagery datasets to assess soil moisture. Based on this, it is anticipated that GEE can be effectively utilized to assess long-term variations of soil moisture average in major dam watersheds, in conjunction with soil moisture observation data from various locations across the country in the future.

• Research in Plant Disease
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• v.30 no.2
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• pp.139-147
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• 2024

Erwinia amylovora is a gram-negative plant pathogen that causes fire blight in apple and pear trees, resulting in significant damage worldwide. In this study, we monitored the emergence of fire blight from 2019 to 2023 to determine the emergence patterns and the factors affecting the outbreak of the disease. As a result of the 5-year survey on the emergence of fire blight, a total of 2,029 cases have emerged, mostly in apple trees of 1,378 cases (67.9%) followed by 645 cases (31.8%) in pear trees, and from quince, hawthorn, and mountain ash trees. Fire blight appeared in specific areas of Gyeonggi, Chungnam, Gangwon, and Chungbuk provinces in 2019, but spread to Andong and Yesan in 2021, Muju and Bonghwa in 2023. In 2020 and 2021, there were 744 and 618 cases of fire blight outbreaks, respectively, compared to other years (188-245 cases/year). Notably, 914 of these cases were observed in apple trees from May to July, with 667 cases reported in Chungju and Jecheon. The incidence of fire blight was positively correlated with the daily maximum temperatures and rainy days in January and February, as well as the rainy days in May and June. The average age of the diseased pear trees was 25 years, higher than the 10-year average age of the apple trees. This study provides fundamental information to understand the status and factors affecting the fire blight emergence in Korea. Prevention measures should be established through continuous analysis of the status of fire blight.

• Bulletin of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.16-29
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• 2024

2014년 4월 18일 오전 8시 48분경 전라남도 병풍도 인근 해역에서 세월호는 전복된 후 침몰하였다. 사고 당시 이 배에는 승객 443명과 선원 및 승무원 33명 모두 476명이 타고 있었고, 이 중 미수습자 5명을 포함하여304명이 생명을 잃었다. 그 동안 공식적인 사고원인 규명활동이 꾸준히 진행되어 이 사고의 원인을 규명하기 위한 조사가 네 차례 있었다. 하지만 아직까지 사고 원인이 무엇인지 명쾌하게 밝혀지지 않고 있다. 이 글에서는 먼저 그동안 있었던 네 차례의 공식적인 세월호 사고원인 규명활동을 정리하였다. 가장 먼저 사고원인 규명활동을 전개한 해양안전심판원 특별조사부는 2014년 사고 직후부터 그해 12월까지 활동하였다. 특별조사부 최종보고서에는 화물의 과적과 평형수 적재 부족으로 인한 선박복원성 기준 미달, 타각의 대각도 조타와 장시간 유지로 인한 부적절한 조타, 화물의 부실한 고박으로 인한 화물의 이동, 수밀문의 관리 부실로 인한 조기 침수와 비상대피장소(muster station)로의 승객대피 조치 미이행을 사고의 원인으로 들고 있다. 2015년 3월부터 2016년 6월까지 활동한 4·16세월호참사 특별조사위원회(특조위)는 '4·16 세월호 참사 특별 조사위원회 청산 백서'만을 간행하고 최종보고서를 제출하지 못한 채 활동을 종료하였다. 세월호 선체조사위원회(선조위)는 2017년 4월부터 2018년 8월까지 활동하였다. 선조위는 세월호 사고원인 규명을 위한 다른 기구에 비해 위원의 구성도 균형이 있었고, 직권사건 위주의 조사방법도 적절하였다. 또한 조타기와 조타 과실 여부, 급선회 항적 및 횡경사와 핀안정기의 물리적 손상에 관한 용역을 국내 여러 기관에 발주하였다. 뿐만 아니라 다양한 해양사고 원인규명 용역에 참여한 실적이 있는 영국의 기술용역회사인 Brookes Bell에 급선회와 빠른 침몰의 원인 조사를 요청하였다. 아울러 세계에서 가장 활발히 수조실험을 수행하고 있는 상업 연구소인 네덜란드의 MARIN에 수조시험과 시뮬레이션도 의뢰하였다. 하지만 아쉽게도 선조위는 서로 다른 사고 원인을 주장하는 두 권의 종합보고서를 간행하였다. 종합보고서로 '내인설' 종합보고서[6]는 타기 솔레노이드 밸브의 고착으로 시작된 급선회를 사고의 직접 원인으로 지목하고 있다. 하지만 '열린안' 종합보고서[7]에서는 수중체와의 충돌을 직접적인 사고 원인으로 밝히고 있다. 마지막으로 가습기살균제 사건과 4·16세월호 참사 특별조사위원회(사참위)가 2019년 3월부터 2022년 9월까지 활동하였다. 사참위는 위원으로 조선해양공학과 항해학 전문가가 포함되어 있지 않아 세월호의 사고원인 규명활동을 효과적으로 수행하기에는 적절하지 못하였다. 사참위는 주로 조타장치 고장에 따른 세월호 전타 선회현상 검증, 세월호 변형 손상부의 확인 및 원인 조사와 세월호 횡경사 원인과 침수과정 분석을 직권 과제로 추진하였다. 또한 네덜란드 MARIN에 자유항주시험을 추가로 의뢰하였으며, 핀란드의 NAPA group에도 복원성 계산과 침수해석을 의뢰하였다. 사참위는 선조위의 두 가지 사고원인에 대해 '내인설'의 솔레노이드 밸브 고착은 사고원인일 가능성이 매우 낮고, '열린안'의 수중체와의 충돌 시나리오는 근거가 부족함을 확인하였다. 이상에서 정리한 바와 같이 규명활동이 진행됨에 따라 사고원인이 수렴되어야 함에도 불구하고 아직까지 원인을 시원하게 밝히지 못하고 있다. 이 글에서는 사고원인 규명활동을 수행한 네 개 기구의 구성과 활동 내용을 비교하고, 사고조사 위원회의 바람직한 구성과 위원회의 운영 방법을 제시하고 있다. 또한 Brookes Bell 보고서에 수록된 출항 당시의 흘수에 근거한 배수량과 선미 램프의 폐쇄 전후의 횡경사각으로부터 도출한 GoM도 소개하고 있다. 아울러 출항 당시의 GoM값으로 추정한 사고 당시의 GoM값도 소개하고 있고, 수중체와의 충돌 시나리오를 후보 사고 시나리오에서 제외시켜야 할 이유도 열거하고 있다. 끝으로 해양사고 원인규명 활동이 보다 과학적으로 그리고 보다 합리적으로 이루어질 수 있기 위해 그리고 우리 사회의 안전문화 제고를 위한 몇 가지의 방안을 제시하고 있다. 또한 세월호 사고로 치른, 아직도 치르고 있는 희생을 딛고 해양안전문화가 한 걸음 더 나아가기 위해서는 세월호 사고의 원인을 반드시 규명해야 한다는 말씀으로 글을 마무리하고 있다.

• Journal of Life Science
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• v.34 no.1
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• pp.18-27
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• 2024

Laying hens are known to be able to 'bio-accumulate' the health-promoting ingredients of their diet into eggs. The purpose of this study was to characterize lignan-rich eggs as functional food fed with Schisandra fruit by-product (SCP). Experimental diets were formulated using yellow corn, rice bran, soybean meal, fish meal, meat bone meal, poultry meal, vitamin premix, mineral premix, CaCO₃, and supplemented Schisandra chinensis by-product. This experiment conducted a completely randomized design with 5 treatments for 5 laying hens. Levels of SCP were fed control diet or each formulated diet containing 1%, 3%, 5% and 7% SCP powder. The weight of eggs and the lignan content in white and yolk of egg were investigated every 7 days. Egg production and egg weight were not affected by diet at less than 5% SCP in the diet, but were significantly reduced when the diet was supplemented with a high concentration of 7% SCP after 3 weeks. Yolks and white in eggs were analyzed by using a high performance liquid chromatography (HPLC) to determine the lignans profile. Higher dietary SCP supplementation significantly increased gomisin N and schisandrin C in Acetonitrile (p<0.05). Gomisin N in egg white increased in a concentration-dependent manner, but shisandrin C not detected. These results indicated that the use of SCP powder in layering diets was effective in egg quality and for the production of lignans fortified eggs. In conclusion, dietary supplementation of Schisandra by-product with less than 5% can produce lignans-enrich eggs used as functional foods.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.371-381
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• 2021

Purpose To evaluate the usefulness and effectiveness of bronchial occluders in the treatment of postoperative bronchopleural fistula (BPF). Materials and Methods The subjects of the study were six out of seven postoperative BPF patients who underwent surgery due to tuberculosis or lung cancer between 2009 and 2019. Each patient had a bronchial occluder inserted to treat BPF that occurred after surgery. Of the six patients, five had lung cancers and one had tuberculosis. Five were male and one was female; their ages ranged from 59 to 74 years, with an average of 69 years. The diagnosis of BPF was based on findings from bronchoscopy and CT, and treatment was initiated approximately 1 to 2 weeks after diagnosis. The technical and clinical success of the bronchial occluders in the treatment of BPF was evaluated. The study assessed the postoperative clinical effects of the occluders, survival duration, and additional treatments. Results All six patients were successfully treated. Clinical success was achieved in five patients, while partial clinical success was achieved in one; there was no clinical failure. No complications during the migration of the device or device perforations were observed. Two patients were diagnosed with BPF by CT, while four were diagnosed by bronchoscopy. Lobectomy, bilobectomy, and pneumonectomy were performed on two patients each. The periods between surgery and diagnosis ranged from 1 to 34 months; the average was 10 months. Four patients (59-103 days; an average of 80.5 days) died and two (313 days, 3331 days) survived. The causes of death were aggravation of the underlying disease (n = 2), pulmonary edema and pleural effusion (n = 1), and pneumonia (n = 1). Additional catheter drainage was performed in one patient, and a chest tube was maintained in two patients. Conclusion Bronchial occluders are useful and effective in the treatment of BPF after pulmonary resection.

• Journal of Science Education
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• v.48 no.1
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• pp.15-30
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• 2024

This study aimed to analyze students' cognitive levels and the cognitive demands of mathematical concepts related to science to understand why students struggle to comprehend scientific concepts and tend to avoid learning them. Initially, the mathematics and science curricula of the 2015 revised curriculum were examined to extract learning elements related to mathematics within middle school science content. The Curriculum Analysis Taxonomy (CAT) was then employed to analyze the cognitive levels required by the learning content. In the domain of chemistry, among a total of 20 learning elements related to mathematics, 12 required an understanding at the level of initial formal manipulation (3A), while 3 necessitated comprehension at the level of later formal manipulation (3B). It was noted that cognitive logic types such as proportional reasoning, mathematical manipulation, and measurement skills were prominently employed in elements corresponding to both 3A and 3B. As for biology, out of 7 learning elements related to mathematics, 3 required an understanding at the level of initial formal manipulation (3A), and 2 necessitated comprehension at the level of later formal manipulation (3B). Elements corresponding to both 3A and 3B in biology predominantly involved correlational logic, indicating a somewhat different cognitive challenge compared to the domain of chemistry. Considering that the average percentage of middle school students capable of formal thinking, as analyzed through the GALT short form, was 12.1% for the first year, 16.6% for the second year, and 29.3% for the third year, it can be concluded that the cognitive demands of mathematics-related chemistry and biology learning content are relatively high compared to students' cognitive levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.25-33
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• 2024

This experiment was conducted at the affiliated farm of the Suncheon University from 2022 to 2023 to investigate the growth, yield, and quality characteristics of soybeans based on the treatment method of Methyl Sulfony Methane (MSM) for the establishment of stable production practices. In the initial investigation of growth characteristics in 2022, an increasing trend in characteristics such as plant height, stem thickness, and branching index was observed as the treatment concentration increased from 50% to 200%. Yield components also followed the same trend, with the basal fertilization + top dressing 3 times at 200% treatment showing the highest yield at 355 kg·10a^-1, with the highest number of pods. In the subsequent study to determine the optimal concentration exceeding 200% in 2023, growth characteristics showed a trend of 400% > 200% > 800%. The basal fertilization + top dressing 3 times at 400% treatment exhibited the longest plant height (106.7 cm) and the most branches (6). In terms of seed quality, this treatment also had the highest proportion (66.9%) of seeds with a diameter over 6.7 mm. Additionally, in yield components such as pods, seeds per pod, and 100-seed weight, the basal fertilization + top dressing 3 times at 400% treatment showed the highest values, resulting in a maximum yield of 374 kg·10a^-1, representing a 23.4% increase compared to the control. Therefore, for the optimal production of high-quality soybeans, it is recommended to apply the treatment of basal fertilization + top dressing 3 times at 400% concentration, with top dressing occurring at 30-day intervals before harvest.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.9-18
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• 2024

The importance of active sonar systems is emerging due to the quietness of underwater targets and the increase in ambient noise due to the increase in maritime traffic. However, the low signal-to-noise ratio of the echo signal due to multipath propagation of the signal, various clutter, ambient noise and reverberation makes it difficult to identify underwater targets using active sonar. Attempts have been made to apply data-based methods such as machine learning or deep learning to improve the performance of underwater target recognition systems, but it is difficult to collect enough data for training due to the nature of sonar datasets. Methods based on mathematical modeling have been mainly used to compensate for insufficient active sonar data. However, methodologies based on mathematical modeling have limitations in accurately simulating complex underwater phenomena. Therefore, in this paper, we propose a sonar signal synthesis method based on a deep neural network. In order to apply the neural network model to the field of sonar signal synthesis, the proposed method appropriately corrects the attention-based encoder and decoder to the sonar signal, which is the main module of the Tacotron model mainly used in the field of speech synthesis. It is possible to synthesize a signal more similar to the actual signal by training the proposed model using the dataset collected by arranging a simulated target in an actual marine environment. In order to verify the performance of the proposed method, Perceptual evaluation of audio quality test was conducted and within score difference -2.3 was shown compared to actual signal in a total of four different environments. These results prove that the active sonar signal generated by the proposed method approximates the actual signal.