• 농업생명과학연구
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• 제53권6호
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• pp.35-44
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• 2019

본 연구는 국내 가선집재 작업 현장 실태에 대한 사례 조사를 통해 작업의 생산성에 영향을 미치는 집재 작업의 설계와 가선 설치의 공학적 문제점을 파악하고, 그로 인해 손실되는 생산성과 증가되는 비용을 분석하기 위한 목적으로 수행되었다. 분석 결과, 가선집재 설계 시 현장의 지형적 입지여건과 공학적 안전성이 충분히 고려되지 않아 대부분 가선의 처짐(deflection)을 확보하지 못하는 것으로 나타났다. 이로 인해 시간 당 생산성이 최대 65%까지 감소하고, 집재비용이 2배 이상 증가되어 전반적인 작업의 효율성이 떨어지는 것으로 나타났다. 따라서 앞으로 국내에서 가선집재 작업이 확대되기 위해서는 작업 안전과 효율을 확보할 수 있는 가선의 설치와 장비의 운용, 불필요한 생산비용을 최소화할 수 있는 현장 기술의 보급이 필요하다.

• 대기
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• 제30권4호
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• pp.391-404
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• 2020

To understand the characteristics of the relationship between visibility and particulate matter (PM) in different meteorological conditions, we investigated the contributions of PM and relative humidity (RH) to visibility in Seoul, South Korea. For the period from 2001 to 2018, both PM and RH show descending trends, resulting in a visibility increase. PM has little impact on the hourly variation of visibility, which could be explained more by the RH variability. Meanwhile, the daily change of PM accounts for daily visibility variation. For the monthly variation of visibility, both PM and RH showed similar influence. The correlation coefficients of PM10, PM2.5, and RH with visibility was -0.486, -0.644, and -0.556, respectively, which became higher during the high PM seasons of spring and winter. The correlation coefficient between PM2.5 and visibility was -0.454 for RH higher than 80%, and -0.780 for RH between 40% and 60%. From 2017 to 2018, there were 10 cases of extreme visibility impairment, among which five cases were incurred by high PM pollution, and two cases were by high humidity. Further analysis with PM chemical composition measurements is required to better understand the characteristics of visibility in Seoul.

• Journal of Trauma and Injury
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• 제34권1호
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• pp.21-30
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• 2021

Purpose: The purpose of this study was to determine the influence of seasons and weather on the volume of trauma patients in central Korea. Methods: The records of 4,665 patients treated at Chungbuk National Hospital Regional Trauma Center from January 2016 to December 2019 were retrospectively reviewed. Meteorological data including hourly temperature (℃), precipitation (mm), humidity (%), and wind speed (m/s) for each district were collected retrospectively. Statistical analysis was done using the independent t-test, one-way analysis of variance (ANOVA), and linear regression analysis. Results: Patients' average age was 53.66 years, with a significant difference between men (49.92 years) and women (60.48 years) (p<0.001). Rolling/slipping down was a prominent cause of injury in winter (28.4%, n=283), with statistical significance (p<0.001). Trauma occurred least frequently in winter (p=0.005). Linear regression analysis revealed an increasing number of patients as the temperature increased (p<0.05), the humidity increased (p<0.001), and the wind speed decreased (p<0.001). Precipitation did not affect patient volume (p=0.562). One-way ANOVA revealed a decreased incidence of trauma when the temperature exceeded 30℃ (p<0.001), and when the humidity was more than 75%, compared to 25-50% and 50-75%. Conclusions: At the regional trauma center of Chungbuk National University Hospital, in central Korea, the number of trauma patients was lowest in winter, and patient volume was affected by temperature, humidity, and wind speed.

• 한국항행학회논문지
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• 제25권1호
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• pp.40-51
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• 2021

본 논문에서는 도심항공 모빌리티(UAM) 시스템을 국내에서 운용하기 위해 필요한 국내외 규정을 분석하여 수직이착륙장의 설계 요구 조건을 도출하고 이착륙 패드의 크기를 규정하였으며, 이를 바탕으로 수직이착륙장 형상을 제안하였다. 먼저, 인구 밀집도가 높은 수도권에 대해 국토교통부에서 제시한 실증노선을 기준으로 수직이착륙장의 시범 위치를 선정하고 각 위치의 특징을 분석하였으며 크기를 측정하여 수직이착륙장의 설치 가능 수를 파악하였다. 이후 수직이착륙장 운영에 필요한 변수들을 설정하여 동시운용과 주기장 수에 따른 시간당, 하루, 한 달 동안의 항공기 운용 가능 대수, 수용 가능 인원, 효율성 등을 계산하였다. 마지막으로, CATIA를 사용하여 가상의 수직이착륙장 형상을 설계요구조건을 적용하여 구현하였다.

• Journal of Trauma and Injury
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• 제33권4호
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• pp.248-255
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• 2020

Purpose: Trauma incidence and hospitalizations of trauma patients are generally believed to be affected by season and weather. The objective of this study was to explore possible associations of the hospitalization rate of trauma patients with weather and time variables at a single regional trauma center in South Korea. Methods: Trauma hospitalization data were obtained from a regional trauma center in South Korea from January 1, 2017 to December 31, 2019. In total, from 6,788 patients with trauma, data of 3,667 patients were analyzed, excluding those from outside the city where the trauma center was located. Hourly weather service data were obtained from the Korea Meteorological Administration. Results: The hospitalization rate showed positive correlations with temperature (r=0.635) and wind speed (r=0.501), but a negative correlation with humidity (r=-0.620). It showed no significant correlation (r=0.036) with precipitation. The hospitalization rate also showed significant correlations with time of day (p=0.033) and month (p=0.22). Conclusions: Weather and time affected the number of hospitalizations at a trauma center. The findings of this study could be used to determine care delivery, staffing, and resource allocation plans at trauma centers and emergency departments.

• 대한본초학회지
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• 제37권4호
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• pp.1-8
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• 2022

Objectives : Dioscorea batas Decaisne (DB) has been known to be good for the digestive system on Eastern Asia. However, the protective effect of DB on acute pancreatitis (AP) has not been studied. In this study, we tried to investigate the protective effect of DB water extract on caerulein-induced AP. Methods : To measure the protective effect of DB on AP, Mice were injected with cholecystokinin analogue caerulein (50 ㎍/kg) hourly for 6 times. DB water extract (200 or 400 mg/kg) or saline (control group) was administered orally 1 h before the first injection of caerulein. The mice were sacrificed at 6 h after the last injection of caerulein. The pancreas tissues and serum samples were immediately taken for further analysis. Results : Administration of DB water extract showed the inhibitory effect on the increase of pancreas weight/body weight ratio, pancreatic histological damage. And the rise of serum lipase level was significantly reduced in DB water extract treatment group during AP in mice. However administration of DB water extract did not show significant reduction in serum amylase level. Also, mRNA levels of pro-inflammatory cytokines Interleukin (IL)-6 and Tumor necrosis factor (TNF)-𝛼 but not IL-1𝛽 were inhibited by administration of DB water extract. Conclusions : Taken together, we found that administration of DB water extract ameliorates the severity of caerulein-induced AP, which suggests the potential to be an effective treatment on AP.

• 한국지열·수열에너지학회논문집
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• 제18권2호
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• pp.10-21
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• 2022

A water source heat pump (WSHP) system is regarded as an energy-efficiency heating and cooling supply system for buildings due to its high energy efficiency and low greenhouse gas emissions. Recently, water sources such as river water, lake water, and raw water are attracting attention as heat sources for a heat pump system in Korea. This paper analyzed the applicability of a river water source heat pump system (RSHP). The river water temperature level was compared with the outdoor air and ground temperature levels to present applicability. In addition, the cooling and heating performance were compared through a simulation approach for the RSHP and a ground source heat pump (GSHP) applied to a large-scale office building. To compare the temperature level, the actual data were applied to the river water and the outdoor air, while the simulation results were applied to the ground circulation water. The results showed that the change in river water temperature throughout the year was similar to the change in outdoor air temperature. However, unlike the outdoor air temperature, the difference between the hourly and daily average river water temperatures was not large. The temperature level of river water was lower during the heating season and somewhat higher during the cooling season than that of the ground circulation water. Finally, the performance of the RSHP system was 13.4% lower than that of the GSHP system on an annual-based.

• 한국항행학회논문지
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• 제26권5호
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• pp.249-260
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• 2022

비행교육을 받는 학생 조종사들은 조종 및 상황판단 능력이 미숙하며 심리적, 육체적, 환경적 등 다양한 요소에 의해 많은 영향을 받는다. 특히 학생 조종사들의 비행교육에 가장 많은 영향을 미치는 요소 중 하나는 기상상태이다. 항공운송사업에 사용되는 대형 항공기와 달리 비행교육에 사용되는 소형 항공기는 기상조건에 따라 비행 제한, 악기상에서는 심리적 압박, 학생 기량 저하 등 교육에 많은 영향을 준다. 그러므로 본 연구에서는 소형 항공기에 많은 영향을 미치는 기상요소에 대한 기상 특성에 대해 분석을 하였다. 분석 결과 계절에 대한 교육 시기 조절, 항공기 가동률 증가, 기상을 고려한 안전한 단독비행 계획을 통하여 조종사 양성 전문교육기관에 효율적이고 안전한 교육훈련 운영방법을 제시하였다.

• 한국환경과학회지
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• 제30권7호
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• pp.585-595
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• 2021

We used seawater temperature data, measured in the Garolim Bay, to analyze temperature variation on an hourly and daily basis. Lagrange's interpolation using before and after data was applied to restore nonconsecutive missing temperature data. The estimated error of the data restoration was 0.11℃. Spectral analyses of seawater temperature showed significant periodicities of approximately 12.4 h (semidiurnal tide) and 15.0 d (long-period tide), which is close to those of M₂ and M_f partial tides. Variation in seawater temperature was correlated more with tidal height than with air temperature around the Garolim Bay. In June and December, when the seawater temperature difference between the inside and outside of the Garolim Bay was very large, the periodicities of 12.4 h and 15.0 d were highly prominent. These results indicate that the exchange of seawater between the inside and outside of the Garolim Bay induced variations in seawater temperature owing to tide. Understanding temperature variation because of tide helps to prevent abnormal mortality of cultured fish and to predict seawater temperature in the Garolim Bay.

• 한국농공학회논문집
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• 제64권2호
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• pp.47-55
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• 2022

The objective of this study was to analyze the effect of the duration and time distribution of probability rainfall on farmland inundation for the paddy fields in the drainage improvement project site. In this study, eight drainage improvement project sites were selected for inundation modeling. Hourly rainfall data were collected, and 20- and 30-year frequency probability rainfalls were estimated for 14 different durations. Probability rainfalls were distributed using Intensity-Duration-Frequency (IDF) and Huff time distribution methods. Design floods were calculated for 48 hr and critical duration, and IDF time distribution and Huff time distribution were used for 48 hr duration and critical duration, respectively. Inundation modeling was carried out for each study district using 48 hr and critical duration rainfalls. The result showed that six of the eight districts had a larger flood discharge using the method of applying critical duration and Huff distribution. The results of inundation depth analysis showed similar trends to those of design flood calculations. However, the inundation durations showed different tendencies from the inundation depth. The IDF time distribution is a distribution in which most of the rainfall is concentrated at the beginning of rainfall, and the theoretical background is unclear. It is considered desirable to apply critical duration and Huff time distribution to agricultural production infrastructure design standards in consideration of uniformity with other design standards such as flood calculation standard guidelines.