• 한국약용작물학회지
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• 제26권6호
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• pp.447-454
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• 2018

Background: The leaf temperature ($T_{LEAF}$) is one of the most important physical parameters governing water and carbon flux, including evapotranspiration, photosynthesis and respiration. Cnidium officinale is one of the important folk medicines for counteracting a variety of diseases, and is particularly used as a traditional medicinal crop in the treatment of female genital inflammatory diseases. In this study, we developed a model to estimate $T_{Leaf}$ of Cnidium officinale Makino based on black globe temperature ($T_{BGT}$). Methods and Results: This study was performed from April to July 2018 in field characterized by a valley and alluvial fan topography. Databases of $T_{LEAF}$ were curated by infrared thermometry, along with meteorological instruments, including a thermometer, a pyranometer, and an anemometer. Linear regression analysis and Student's t-test were performed to evaluate the performance of the model and significance of the parameters. The correlation coefficient between observed $T_{LEAF}$ and calculated $T_{BGT}$ obtained using an equation, developed to predict $T_{LEAF}$ based on $T_{BGT}$ was very high ($r^2=0.9500$, p < 0.0001). There was a positive relationship between $T_{BGT}$ and solar radiation ($r^2=0.8556$, p < 0.0001), but a negative relationship between $T_{BGT}$ and wind speed ($r^2=0.9707$, p < 0.0001). These results imply that heat exchange in leaves seems to be mainly controlled by solar radiation and wind speed. The correlation coefficient between actual and estimated $T_{BGT}$ was 0.9710 (p < 0.0001). Conclusions: The developed model can be used to accurately estimate the $T_{Leaf}$ of Cnidium officinale Makino and has the potential to become a practical alternative to assessing cold and heat stress.

• 한국해양공학회지
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• 제33권5호
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• pp.470-478
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• 2019

Because the global positioning system (GPS) is not available in underwater environments, an inertial navigation system (INS)/doppler velocity log (DVL) integrated navigation system is generally implemented. In general, an INS/DVL integrated system adopts a loosely coupled method. However, in this loosely coupled method, although the measurement equation for the filter design is simple, the velocity of the body frame cannot be accurately measured if even one of the DVL transducer signals is not received. In contrast, even if only one or two velocities are measured by the DVL transducers, the tightly coupled method can utilize them as measurements and suppress the error increase of the INS. In this paper, a filter was designed to regenerate the measurements of failed transducers by taking advantage of the tightly coupled method. The regenerated measurements were the normal DVL transducer measurements and the estimated velocity in RPM. In order to effectively estimate the velocity in RPM, a filter was designed considering the effects of the tide. The proposed filter does not switch all of the measurements to RPM if the DVL transducer fails, but only switches information from the failed transducer. In this case, the filter has the advantage of being able to be used as a measurement while continuously estimating the RPM error state. A Monte Carlo simulation was used to determine the performance of the proposed filters, and the scope of the analysis was shown by the standard deviation ($1{\sigma}$, 68%). Finally, the performance of the proposed filter was verified by comparison with the conventional tightly coupled method.

• 한국수자원학회논문집
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• 제53권12호
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• pp.1109-1117
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• 2020

본 연구에서는 토사유출량 산정에 가장 많이 사용되고 있는 RUSLE방법과 MSDPM, 그리고 LADMP를 실제 산지하천에 적용하여 토사유출량을 비교·분석하였다. 기존 토사유출량 산정 시 사용자가 주관적으로 선택할 수 있는 식생피복인자(C), 보전관리인자(P), 토양침식조절인자(VM)가 토사유출량 산정결과에 미치는 영향을 비교하였다. 또한 MSDPM과 LADMP을 사용하여 10년, 20년, 30년, 50년, 100년, 200년 빈도 재현기간의 강우강도에 의한 토사유출량을 산정하고, RUSLE의 결과값과 비교 분석하였다. 이를 통하여 식생피복인자(C), 보전관리인자(P), 토양침식조절인자(VM)값에 따라 토사량의 차이가 최대 400%까지 발생하는 것을 확인할 수 있었으며, MSDPM과 LADMP의 국내 적용 가능성을 확인하였다.

• 한국물환경학회지
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• 제27권5호
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• pp.625-633
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• 2011

A long-term water quality monitoring in the Han River Basin reveals a consistent increasing trend for the concentration of refractory organic matter (R-OM) in major monitoring sites of the watershed. Because the determination of R-OM concentrations typically requires a long time of microbial incubation, it is essential to present the estimation indices for R-OM for an efficient watershed management. In this study, a number of surface water samples were classified into three groups, each of which were collected from Lake Paldang, rivers at rain and non-rain events, respectively. The corresponding R-OM concentrations were correlated with biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) concentrations as well as ultraviolet and fluorescence intensities of the filtered samples. Among the traditional organic matter parameters, TOC exhibited the highest correlation coefficient with the R-OM concentrations regardless of the types of the sample groups. The equations for conversing TOC into R-OM concentrations were finally suggested as $0.43{\times}TOC+1.12$, $0.44{\times}TOC+0.61$, $0.24{\times}TOC+1.28$ for river samples at rain and non-rain events, and lake samples, respectively. TOC-BOD(C), the values of the TOC concentrations subtracted by carbon-converted BOD concentrations, was a good index for estimating the absolute concentrations of R-OM. UV absorbance at 254 nm was well correlated with R-OM concentrations of river samples while fluorescence intensities at 350 nm showed an excellent relationship with R-OM concentration of the lake samples. Our results suggests that simple spectroscopic parameters could be applied for in-situ monitoring tool techniques in watersheds.

• Animal Bioscience
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• 제34권4호
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• pp.558-566
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• 2021

Objective: Objectives were to estimate energy and protein requirements of dairy crossbred steers, as well as to evaluate equations previously described in the literature (HH46 and CS16) to predict the carcass and empty body chemical composition of crossbred dairy cattle. Methods: Thirty-three Holstein×Zebu steers, aged 19±1 months old, with an initial shrunk body weight (BW) of 324±7.7 kg, were randomly divided into three groups: reference group (n = 5), maintenance level (1.17% BW; n = 4), and the remaining 24 steers were randomly allocated to 1 of 4 treatments. Treatments were: intake restricted to 85% of ad libitum feed intake for either 0, 28, 42, or 84 d of an 84-d finishing period. Results: The net energy and the metabolizable protein requirements for maintenance were 0.083 Mcal/EBW0.75/d and 4.40 g/EBW0.75, respectively. The net energy (NEG) and protein (NPG) requirements for growth can be estimated with the following equations: NEG (Mcal/kg EBG) = $0.2973_{({\pm}0.1212)}{\times}EBW^{0.4336_{({\pm}0.1002)}$ and NPG (g/d) = 183.6(±22.5333)×EBG-2.0693(±4.7254)×RE, where EBW, empty BW; EBG, empty body gain; and RE, retained energy. Crude protein (CP) and ether extract (EE) chemical contents in carcass, and all the chemical components in the empty body were precisely and accurately estimated by CS16 equations. However, water content in carcass was better predicted by HH46 equation. Conclusion: The equations proposed in this study can be used for estimating the energy and protein requirements of crossbred dairy steers. The CS16 equations were the best estimator for CP and EE chemical contents in carcass, and all chemical components in the empty body of crossbred dairy steers, whereas water in carcass was better estimated using the HH46 equations.

• 지질공학
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• 제30권4호
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• pp.635-648
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• 2020

본 연구는 회전관입말뚝의 이음부를 용접이나 볼트가 필요 없는 육각형 이음부로 개선하여 압축재하시험을 수행하였다. 또한 인발시험의 경우 기존 방법과 유사하게 볼트체결 방법으로 적용하여 인발시험을 수행하였다. 회전관입말뚝의 지지력을 평가하기 위해 현장시험 2지역을 선정하였다. 하중재하시험은 정재하시험과 인발시험을 수행하였으며 회전관입말뚝에 대한 지지력을 평가하였다. 현장시험결과, 정재하시험시 중력식 그라우트를 적용한 말뚝에서 AC 358 Code에 따른 지지력평가 결과 600 kN 이상으로 나타났으며, 그라우트가 없는 말뚝에서는 600 kN 이하의 지지력을 보여 중력 그라우팅이 필요함을 확인하였다. 또한 현장시험결과를 고려하여 지지력을 평가하였으며, 적은 표본에 의해서 도출된 결과로 추후 기초자료로 활용될 수 있을 것으로 판단된다.

• 보건행정학회지
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• 제31권1호
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• pp.125-139
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• 2021

Background: In Korea, the health gap widens due to the number of medical resources and access to medical services between metropolitan and rural. The purpose of this study is to identify the impact of residential migration on medical utilization and accessibility. Methods: This study extracted 528,516 claimed cases in the National Health Insurance Service-Cohort Sample Database from 2006 to 2015. Subjects were classified into two groups by the magnitude of the region, the metropolitan and the rural. The inversed probability weights were calculated for each group. And coefficients of the two-part model were estimated by generalized estimation equation. Results: Those who moved region from metropolitan to rural tend to increase the length of stay and inpatients with ambulatory care sensitive conditions (ACSC) disease. Contrariwise, those who moved areas from rural to metropolitan tend to decrease the total medical cost, the adjusted patient days, the number of outpatients and the number of outpatients and inpatients with ACSC disease. Conclusion: This study identified that between the residents who continued to reside in the region and the migrants, there were significant differences in the medical accessibility, quality of primary care, and unmet medical need.

• 대한조선학회논문집
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• 제57권6호
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• pp.322-330
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• 2020

This study deals with underwater explosion (UNDEX) characteristics of various non-explosive underwater shock sources for the development of non-explosive underwater shock testing devices. UNDEX can neutralize ships' structure and the equipment onboard causing serious damage to combat and survivability. The shock proof performance of naval ships has been for a long time studied through simulations, but full-scale Live Fire Test and Evaluation (LFT&E) using real explosives have been limited due to the high risk and cost. For this reason, many researches have been tried to develop full scale ship shock tests without using actual explosives. In this study, experiments were conducted to find the characteristics of the underwater shock waves from actual explosive and non-explosive shock sources such as the airbag inflators and Vaporizing Foil Actuator (VFA). In order to derive the empirical equation for the maximum pressure value of the underwater shock wave generated by the non-explosive impact source, repeated experiments were conducted according to the number and distance. In addition, a Shock Response Spectrum (SRS) technique, which is a frequency-based function, was used to compare the response of floating bodies generated by underwater shock waves from each explosion source. In order to compare the magnitude of the underwater shock waves generated by each explosion source, Keel Shock Factor (KSF), which is a measure for estimating the amount of shock experienced by a naval ship from an underwater explosionan, was used.

• Journal of Preventive Medicine and Public Health
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• 제54권6호
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• pp.441-450
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• 2021

Objectives: Socioeconomic disadvantages interact with numerous factors which affect geriatric mental health. One of the main factors is the social relations of the elderly. The elderly have different experiences and meanings in their social lives depending on their socio-cultural environment. In this study, we compared the effects of social relations on depression among the elderly according to their living arrangement (living alone or living with others) and residential area. Methods: We defined social relations as "meetings with neighbors" (MN). We then analyzed the impact of MN on depression using data from the Korean Longitudinal Study of Aging Panel with the generalized estimating equation model. We also examined the moderating effect of living alone and performed subgroup analysis by dividing the sample according to which area they lived in. Results: MN was associated with a reduced risk of depressive symptoms among elderlies. The size of the effect was larger in rural areas than in large cities. However, elderly those who lived alone in rural areas had a smaller protective impact of MN on depression, comparing to those who lived with others. The moderating effect of living alone was significant only in rural areas. Conclusions: The social relations among elderlies had a positive effect on their mental health: The more frequent MN were held, the less risk of depressive symptoms occurred. However, the effect may vary depending on their living arrangement and environment. Thus, policies or programs targeting to enhance geriatric mental health should consider different socio-cultural backgrounds among elderlies.

• 대한토목학회논문집
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• 제41권6호
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• pp.637-644
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• 2021

대부분 동적 성능 평가는 반복 가력 실험을 수행함으로써 구조물의 동적 응답을 평가할 수 있다. 일반적으로 강재는 재하속도 의존성 재료로 알려져 있으며 기둥 부재의 횡방향인 수평방향 가력 시 기둥 부재의 축력인 수직하중이 작용하면 부재의 응답에 영향을 미친다. 하지만, 강재 기둥 구조물의 실험 시 수평 및 수직하중을 동시에 제어하는 것이 어려워 관련 연구는 부족한 실정이다. 본 연구에서는 기둥 부재를 ATS Compensator와 FLB 시스템을 이용하여 수평 및 수직하중을 고속으로 제어하였다. 실험은 H-형 구조용 압연강재인 SS275을 이용하여 수직 하중을 제어하면서 여러 속도로 단조 및 반복 가력 실험을 수행하고 부재의 항복 하중을 비교하였다. 또한, 유한요소해석 시 재하속도에 따라 새로운 항복 응력을 제안하고 수치해석을 통해 비교하였다.