• Journal of agriculture & life science
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• v.53 no.6
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• pp.35-44
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• 2019

The objectives of this study were to identify engineering problems in the design and installation of cable logging operation that affects productivity through case study of actual logging sites, and to analyze associated productivity loss and increased cost. As a result of the study, when the geographic conditions and engineering safety of the site are not sufficiently considered, deflection of the cable line can not be secured. Hourly productivity of the operation decreased to 65% and the logging cost increased by more than two times compared to the productive yarding operation, which lowered overall efficiency of the operation. Thus, it is required to spread filed technologies that minimize unnecessary production cost incurred due to the in-efficient logging operations as well as secure work safety and efficiency to expand cable logging operation throughout the country.

• Atmosphere
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• v.30 no.4
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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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• v.34 no.1
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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.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.40-51
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• 2021

In this paper, the design requirements was produced by analyzing domestic and foreign regulations of the vertical takeoff and landing site required to operate the urban air mobility (UAM) system in Korea and the size of the take-off and landing pads were defined, and the configuration of vertiport was proposed. First, for the metropolitan area with high population density, pilot locations of the vertical take-off and landing site were selected based on the demonstration routes suggested by the Ministry of Land, Infrastructure and Transport and analyzed the characteristics of each location and determined the number of possible installations of vertiport by measuring each site. After that, variables necessary for the operation of the vertical takeoff and landing area were set, and the hourly, daily, monthly aircraft operating cycle, the number of acceptable people, and efficiency were calculated according to the number of simultaneous operation and the number of stand. Finally, using CATIA, the configurations of the virtual vertiport was created by applying the design requirements.

• Journal of Trauma and Injury
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• v.33 no.4
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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.

• The Korea Journal of Herbology
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• v.37 no.4
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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.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.18 no.2
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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.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.249-260
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• 2022

Student pilots receiving flight education are inexperienced in piloting and situation judgment skills and are greatly affected by various factors such as psychological, physical, and environmental factors. In particular, one of the most influential factors in the flight education of student pilots is the weather conditions. Unlike large aircraft used in the air transportation business, small aircraft used for flight education have a great impact on education, such as flight restrictions depending on weather conditions, psychological pressure in severe weather, and deterioration of student skills. Therefore, in this study, the meteorological characteristics of meteorological factors that have a great influence on small aircraft were analyzed. As a result of the analysis, an efficient and safe training operation method was suggested to a professional pilot aviation training organization through the adjustment of the training period for the season, the increase in aircraft operation rate, and a safe solo flight plan considering the weather.

• Journal of Environmental Science International
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• v.30 no.7
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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.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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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.