• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.467-467
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• 2015

Sustainable water resource management requires the assessment of hydrological variability in response to climate fluctuations and anthropogenic activities. Determining quantitative estimates of water balance and total basin discharge are of utmost importance to understand the variations within a basin. Hard-to-reach areas with few infrastructures, coupled with lengthy administrative procedures makes in-situ data collection and water management processes very difficult and unreliable. In this study, the hydrological behavior of Lake Chad whose extent, extreme climatic and environmental conditions make it difficult to collect field observations was examined. During a 10 year period [January 2003 to December 2013], dataset from space-borne and global hydrological models observations were analyzed. Terrestial water storage (TWS) data retrieved from Gravity Recovery and Climate Experiment (GRACE), lake level variations from Satellite altimetry, water fluxes and soil moisture from Global Land Data Assimilation System (GLDAS) were used for this study. Furthermore, we combined altimetry lake volume with TWS over the lake drainage basin to estimate groundwater and soil moisture variations. This will be validated with groundwater estimates from WaterGAP Global Hydrology Model (WGHM) outputs. TWS showed similar variation patterns Lake water level as expected. The TWS in the basin area is governed by the lake's surface water. As expected, rainfall from GLDAS precedes GRACE TWS with a phase lag of about 1 month. Estimates of groundwater and soil moisture content volume changes derived by combining altimetric Lake Volume with TWS over the drainage basin are ongoing. Results obtained shall be compared with WaterGap Hydrology Model (WGHM) groundwater estimate outputs.

• 디지털융복합연구
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• 제19권9호
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• pp.257-269
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• 2021

논문은 심탄도(BCG, Ballistocardiogram) 센서를 이용하여 생체신호 데이터를 비침습, 무구속적인 방식으로 수집하고, ICT 기술과 고성능 컴퓨팅 환경에서 인공지능 기계학습 알고리즘을 활용하여 데이터 기반 혈당 예측 알고리즘 모델 개발 및 검증하는 방법을 제시하고 연구하는 것이다. 혈당수치 예측모델은 MLP 아키텍처에 입력노드는 심박수, 호흡수, 심박출량, 심박변이도, SDNN, RMSSD, PNN50, 나이, 성별이며, 은닉층 7개를 사용하였다. 실험 결과는 5회 실험한 학습데이터의 평균 MSE, MAE 및 RMSE 값은 각각 0.5226, 0.6328 및 0.7692이며 검증데이터 평균 값은 각각 0.5408, 0.6776, 0.7968이었으며, 결정계수(R2) 수치는 0.9997의 결과를 보였다. 데이터를 기반으로 한 혈당수치를 예측하는 모델을 표준화하고 데이터셋 수집과 예측 정확성을 검증하는 연구가 계속적으로 진행된다면 비침습 방식의 혈당 수준 관리에 활용될 수 있을 것으로 사료된다.

• 한국농공학회논문집
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• 제63권5호
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• pp.1-11
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• 2021

Soil moisture plays a critical role in hydrological processes, land-atmosphere interactions and climate variability. It can limit vegetation growth as well as infiltration of rainfall and therefore very important for agriculture sector and food protection. Recently, due to the increased damage from drought caused by climate change, there is a frequent occurrence of shortage of agricultural water, making it difficult to supply and manage stable agricultural water. Efficient water management is necessary to reduce drought damage, and soil moisture management is important in case of upland crops. In this study, soil moisture was calculated based on the water balance model, and the suitability of soil moisture data was verified through the application. The regional soil moisture was calculated based on the meteorological data collected by the meteorological station, and applied the Runs theory. We analyzed the spatiotemporal variability of soil moisture and drought impacts, and analyzed the correlation between actual drought impacts and drought damage through correlation analysis of Standardized Precipitation Index (SPI). The soil moisture steadily decreased and increased until the rainy season, while the drought size steadily increased and decreased until the rainy season. The regional magnitude of the drought was large in Gyeonggi-do and Gyeongsang-do, and in winter, severe drought occurred in areas of Gangwon-do. As a result of comparative analysis with actual drought events, it was confirmed that there is a high correlation with SPI by each time scale drought events with a correlation coefficient.

• Nutrition Research and Practice
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• 제17권4호
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• pp.747-761
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• 2023

BACKGROUND/OBJECTIVES: In Korea, studies of diet in elementary school children are hindered by the need for a comprehensive dietary assessment tool. Thus, the aim of this study was to develop a semi-quantitative food frequency questionnaire (FFQ) for Korean elementary school children. SUBJECTS/METHODS: The 24-h recall data for 1,624 subjects aged 6-11 yrs from the seventh Korea National Health and Nutrition Examination Survey were used to extract the items included in the questionnaire. The FFQ items were developed by selecting major dishes based on the results of nutritional contribution and between-person variability for energy and 14 nutrients (carbohydrate, protein, fat, crude fiber, calcium, phosphorous, iron, sodium, potassium, vitamin A, thiamin, riboflavin, niacin, and vitamin C). We selected the major dishes with over 90% of the total contribution to each nutrient and with over 90% of the accumulated R² for each nutrient. Among the 452 dishes, we selected 248 dishes contributing more than 1% of the total consumption. RESULTS: Finally, the FFQ included 107 items combined from 248 dishes based on nutrient profile and recipe. The FFQ items accounted for an average of 88.6% of the energy, 14 nutrient intakes, and 91.4% of the between-person variability. Quantities of dietary intake were assessed by 9 categories of frequency and 3 categories of portion size. Percentages of coverage for energy, protein, fat, carbohydrate, and calcium were 90.2%, 87.8%, 89.9%, 90.8%, and 88.7%, respectively. CONCLUSIONS: We developed a dish-based, semi-quantitative FFQ comprising 107 items for Korean elementary school children aged 6 to 11. Further studies are needed to evaluate the reproducibility and validity of this FFQ for elementary school children.

• Korean Journal of Radiology
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• 제20권1호
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• pp.148-157
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• 2019

Objective: To evaluate the current status of managing adverse reactions to iodinated contrast media (ICM) for computed tomography in referral hospitals in South Korea compared with hospitals in other countries. Materials and Methods: This survey investigation involved 59 Korean and 15 overseas hospitals using guideline-based questionnaires consisting of 24 items in 7 main categories related to managing adverse reactions to ICM. Results: Informed written consent with risk factor evaluation was appropriately performed in most of the Korean hospitals. There was considerable variability in assessing renal function across the hospitals; serum creatinine level was used as a reference in 76.4% of Korean hospitals. The Korean hospitals preferred a more stringent approach to determining normal renal function (p = 0.01), withholding metformin (p = 0.01), and fasting before ICM exposure (p < 0.001) compared with overseas hospitals. All the Korean hospitals had an emergency protocol and in-hospital system for adverse reactions to ICM. The Korean (87.7%) and overseas hospitals (100%) were similarly equipped with epinephrine (p = 0.332), but only 38.6% of Korean hospitals were equipped with a bronchodilator (p = 0.004). For patients with a previous hypersensitivity reaction to ICM, 62.3% of Korean hospitals pre-medicated with anti-histamine and corticosteroid according to the severity of the previous reaction, and changed the culprit ICM in 52.8%, while skin test was performed in 17%. Conclusion: In general, Korean referral hospitals were well-prepared regarding informed consent, protocol, and an in-hospital system for managing adverse reactions to ICM. Nevertheless, there was considerable variability in details and management, thus requiring standardization by reflecting current guidelines.

• 생태와환경
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• 제49권4호
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• pp.354-374
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• 2016

본 연구는 2012년 5월부터 2015년 12월까지 북한강과 남한강의 유입부를 포함하는 팔당호의 5개 지점에서 시공간적 수질 변동성을 강우 수문학과 비교 고찰하였다. 조사기간 동안 기초 수질요인들의 변동은 계절적 영향이 컸다. 특히, 수온성층은 수심이 깊은 댐 부근에서 형성되었고, 연도에 따라 빈산소 장기화도 관찰되었다. 질소(N) 계열 영양염의 증가는 유량이 빈약할 때 나타났고, 이때 $NH_4$는 하수 처리수의 영향을 크게 받아 $NO_3$와 상반되는 경향을 나타내었다. 인(P)의 증가는 유량이 크거나 극심한 가뭄이 지속될 때이었고, P 영양염 결핍도 빈번하게 관찰되었다. Chl-a의 증감은 유량 변동과 역상관 관계를 보였고, 그 값이 높을 때 AGP 값은 낮았다. 팔당호의 수질 변동성은 유역으로부터 하수 처리수(총량: $472{\times}10^3m^3d^{-1}$)의 오염원을 기반으로 한 유입, 방류 및 취수의 패턴에서 직간접적 관련성과 그 영향을 찾을 수 있었다. 또한 수질의 시공간적 변동 과정에서 기상(장마, 태풍, 이상강우 및 폭염더위) 수문(유량과 수위)학적 인자는 펄스, 희석, 역류, 흡수, 농축 및 침전 등 형태로서 작용하였다. 하천형 저수지인 팔당호의 수질 변동은 매우 역동적이며, 국내 최대 상수원의 오염 수준을 경감하기 위한 실효 대책으로 기상 수문에 기초한 육수학적 조사연구와 P-free 하수 처리 정책 실현의 필요성을 제안한다.

• 한국작물학회지
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• 제50권4호
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• pp.238-246
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if variable rate treatment (VRT) of N fertilizer, that was prescribed for site-specific management at panicle initiation stage, could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, 33kg N/ha at PIS) method. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model· equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for the calculation of the required N were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with an average of 57kg/ha that was higher than 33 kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%$ and $7.1\%$ in VRT from $14.6\%$ and $13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. In conclusion the procedure used in this paper was believed to be reliable and promising method for reducing within-field spatial variability of rice yield and protein content. However, inexpensive, reliable, and fast estimation methods of natural N supply and plant growth and nutrition status should be prepared before this method could be practically used for site-specific crop management in large-scale rice field.

• 한국수자원학회논문집
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• 제55권12호
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• pp.1021-1030
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• 2022

최근 우리나라의 물 관련 정책은 수량-수질-수생태 통합관리 방향으로 진행되고 있으며, 특히 하천의 자연성 회복이 주요한 이슈가 되고 있다. 이수기 댐 운영에 있어서는 가뭄, 물 수요 증가 등으로 용수공급 효과를 극대화시킬 수 있는 부족분 공급방식을 적용하고자하는 시도들이 이어지고 있다. 댐 운영에 부족분 공급방식을 적용하면 댐의 용수공급능력을 극대화 시킬 수는 있지만 하류 하천의 유량이 일정하게 유지된다는 특징이 있다. 자연하천은 오랜 시간동안 형성된 하나의 생태계로 유량의 변동성에 큰 영향을 받는다. 결국 부족분 공급방식을 적용한 댐 운영은 수량 관리에서는 효과적이지만 하천의 자연성 회복 및 수생태 측면에서는 부정적 영향을 미칠 수있다. 본 연구에서는 저수지 모의를 통해 보장량 공급방식, 부족분 공급방식, 선택적 부족분 공급방식 등의 댐 운영이 하류 하천 유황에 미치는 영향을 분석하고, 각 운영방식의 적용 효과에 대해 분석하고자 하였다. 그 결과 보장량 공급방식을 적용하면 하천의 유량 변동성은 크게 유지할 수 있으나 댐의 용수공급능력은 크지 않은 것으로 나타났다. 부족분 공급방식을 활용하면 용수공급능력을 증대시킬 수는 있으나 하류의 평수량과 갈수량의 차이가 매우 작아 유량의 변동성 측면에서는 매우 취약한 것으로 확인되었다. 선택적 부족분 공급방식을 적용할 경우 기간신뢰도를 95% 이상으로 유지하며, 하류 하천의 유황은 보장량 공급방식을 적용할 때와 유사하게 유지할 수 있는 것으로 분석되었다.

• 한국안전학회지
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• 제37권1호
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• pp.64-69
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• 2022

The study measured a subway construction worker's Macpa stress by Heart Rate Variability measuring instrument and conducted a survey of Korean job stress from subway construction workers. Also, the study analyzed the relationship between Macpa stress index and Korean job stress result and suggested managing stress method for each item. According to National Statistical Office data, the first line subway in Seoul was started to open in 1974. The extended total length is 996 kilometers until 2019. Many aged workers are currently working at subway construction sites due to the avoidance of young workers since the past until now. It means that the elderly has a substantial portion among subway construction workers. The productivity has been adversely affected by health problems due to the aging of workers, job stress due to heavy work, and personal health problems. So, the regulation and policies on job stress health management are being strengthened. The data were measured Macpa stress by machine measuring heart rate variability and conducted Korean job stress survey(shortened) from Sa-sang to Ha-dan line Busan subway construction workers for analyzing the relationship. Independent variable were age, job duration, job position, employment type, working type in this study. Macpa's dependent variable was stress index and Korean job stress survey(shortened)'s dependent variables were job requirements, job autonomy, relationship conflict, job instability, organizational structure, inappropriate compensation, working place culture, and total score. SPSS 12.0 K Statistics Program was used for statistical analysis. Kruskal-wallis test, a nonparametric statistical analysis, was used because the data are difficult to be assumed as normal distribution. As a result, the paper indicated the significant correlation between Macpa stress index and Korean job stress(short version). The elderly workers presented higher Macpa index and higher job stress due to aging and heavy-duty work. The majority workers were daily workers who had unstable working condition and uncertainty about the future. The study suggested a manual that could reduce job stress for subway construction workers and future study deriving management tool through analyzing job stress factor is necessary.

• Journal of Acupuncture Research
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• 제23권1호
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• pp.25-38
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• 2006

Objectives : Acupuncture has been widely used in oriental medicine. The aim of this research is to study how does the interaction between reinforcement-reduction by twirling nine and six and subject's cold or heat tendency effect on Heart Rate Variability. Methods : We divided our subjects into 3 groups at random and classified subjects by their cold or heat tendency using questionnaire for cold-heat patternization. Group 1 is acupuncture at shinmun(HT7) reinforcement group, 2 is acupuncture at shinmun(HT7) reduction group, 3 in acupuncture at hapkok(LI4) group. According to their group, we acupunctured. Before and after acupuncture Heart Rate Variability raw data were measured during 5 minutes. LF, HF, LF norm HF norm were calculated. We analyzed these data using 3-way repeated ANOVA, Paired student T-Test. Results : 3-way repeated ANOVA showed significant interaction among LF, each group and subject's cold heat tendency(p<0.05). Paired student T-Test showed significant differences between before and after acupuncture at shinmun(HT7) reinforcement method in cold tendency men and acupuncture at shinmun(HT7) reduction method in heat tendency men(p<0.05). Conclusion : These results suggest that acupuncture at Shinmun(HT7) has an effect on declining sympathetic nerve function and has an effect on stabilizing mind through Interaction between reinforcement-reduction by twirling nine and six and subject's cold or heat tendency. We propose that more prudent care is needed about subject's cold or heat tendency and acupuncture technique of reinforcement-reduction to achieve the most suitable treatment effect.