• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.122-133
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• 2021

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chamber Method (CCM) conducted by a Continuous Radon Monitor (CRM) has been used for the rates of radon exhalation. Based on equations of previous references, the indoor radon concentrations were deducted. As a result, the radon surface exhalation rates resulted in the 1.4208 to 3.0293 Bq·㎡·h-1 range. Significant differences were found among Hwangtohs according to production regions. Materials with higher radon concentration required a longer time to reach a quasi-steady state in a given environment, in other words, the number of half-life cycles increased from a set starting point. The experimentally identified Hwangtohs demonstrated its safety for construction purposes. There exists, so far, a possibility to exert influence radon emanation due to unidentified factors. Therefore, it is necessary to corroborate with more research by increasing the number of Hwangtohs, considering the other references reported high radon exhalation rates. In addition, it is highly recommended that the radon exhalation rates should be measured for all building materials for preventing human health before the material usage.

• 한국건설관리학회논문집
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• 제23권1호
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• pp.113-117
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• 2022

적층제조(AM, 일명 3D프린팅)기술은 디자인 자유도가 높고 디지털화된 기술의 특성으로 품질데이터의 예측·관리가 용이한 형태로 존재한다. 이러한 이점으로 AM기술은 다양한 산업에 적용되고 있다. 특히 건축물과 기반시설을 AM기술로 제조하는 방법이 건설 산업에 제안되고 있다. 다만, 다소 부족한 기술의 역사와 품질 및 시공 관리방법의 미비, 제조상품의 인증과 같은 문제로 인해 기술사용이 제한되고 있다. 따라서 간접적인 형태로 AM기술을 활용하여 건축 상품제조를 구현하고 있다. 특히, 거푸집을 적층 제조하고 건축 소재를 투입하여 상품으로 구현하는 방법이 확인되고 있다. 본 연구에서는 대형크기의 거푸집을 적층제조하고 건축 상품을 구현하기 위해 하이브리드 압출적층제조를 활용한다. 또한, 적층제조과정에서 생산성과 경제성을 예측할 수 있는 인자를 확인한다. 결과적으로, 건축물의 구현결과와 생산 비용과 시간을 줄이기 위한 형상설계 최적화 방법을 제안한다.

• Animal Bioscience
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• 제35권6호
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• pp.804-813
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• 2022

Objective: A formula is needed that is practical for current livestock breeding methods and that predicts the approximate rate of inbreeding (ΔF) in populations where selection is performed according to four-path programs (sires to breed sons, sires to breed daughters, dams to breed sons, and dams to breed daughters). The formula widely used to predict inbreeding neglects selection, we need to develop a new formula that can be applied with or without selection. Methods: The core of the prediction is to incorporate the long-tern genetic influence of the selected parents in four-selection paths executed as sires to breed sons, sires to breed daughters, dams to breed sons, and dams to breed daughters. The rate of inbreeding was computed as the magnitude that is proportional to the sum of squared long-term genetic contributions of the parents of four-selection paths to the selected offspring. Results: We developed a formula to predict the rate of inbreeding in populations undergoing four-path selection on genomically enhanced breeding values and with discrete generations. The new formula can be applied with or without selection. Neglecting the effects of selection led to underestimation of the rate of inbreeding by 40% to 45%. Conclusion: The formula we developed here would be highly useful as a practical method for predicting the approximate rate of inbreeding (ΔF) in populations where selection is performed according to four-path programs.

• 한국기계가공학회지
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• 제21권4호
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• pp.1-13
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• 2022

Household refrigerator cabinets must undergo cyclic testing at -20 ℃ and 65 ℃ for quality control (QC) after their production is complete. These cabinets were assembled from different materials, including acrylonitrile butadiene styrene (ABS), polyurethane (PU) foam, and steel plates. However, different thermal expansion values could be observed owing to differences in the mechanical properties of the materials. In this study, a technique to predict delamination on a refrigerator wall caused by thermal deformation was developed. The mechanical properties of ABS and PU foams were tested, theload factors causing delamination were analyzed, delamination was observed using a high-speed camera, and comparison and verification in terms of stress and strain were performed using a finite element model (FEM). The results indicated that the delamination phenomenon of a refrigerator wall can be defined in two cases. A method for predicting and evaluating delamination was established and applied in an actual refrigerator. To determine the effect of temperature changes on the refrigerator, strain measurements were performed at the weak point and the stress was calculated. The results showed that the proposed FEM prediction technique can be used as a basis for virtual testing to replace future QC testing, thus saving time and cost.

• Animal Bioscience
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• 제36권4호
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• pp.601-608
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• 2023

Objective: This study was conducted to investigate the effects of energy and protein levels in the diet of Hanwoo heifers on growth response and animal behavior. Methods: Forty heifers were randomly allocated into three experimental groups according to the target daily weight gain in 8 pens (T-0.2, 2 replications; T-0.4 and -0.6, 3 replications) based on similar body weight (BW) and age in months. The target average daily gain (ADG) was set at 0.2 (T-0.2), 0.4 (T-0.4), and 0.6 kg/d (T-0.6), and feed was based on National Institute of Animal Science (NIAS, 2017). In order to minimize hunger stress of T-0.2 and -0.4, the feeding ratio of rice straw was set to 55%, 50%, and 45% for T-0.2, -0.4 and T-0.6, respectively, so that the dry matter (DM) intake for all treatment groups was uniform but the energy and protein levels in the diet were adjusted differently. A total of 6 items (lying, standing, eating, rumination, walking and drinking) of animal behavior were analyzed. Results: During the whole period of the experiment, the ADG of the T-0.2, -0.4 and -0.6 treatments were 0.48, 0.56, and 0.65 kg/d (p<0.05), respectively, showing higher gain than the predicted value, especially for the low target ADG group. Based on these results, regression equations for the total digestible nutrient (TDN) and crude protein (CP) requirements were derived. No behavioral differences were found according to the energy and protein levels in the diet because the DM intake was kept constant by adjusting the roughage and concentration ratio. However, eating time was longer (p<0.05) at T-0.2 than T-0.6 during the whole day. Conclusion: Through this study, it was possible to derive regression equations for predicting TDN and CP requirements according to the target ADG and BW.

• 한국전자통신학회논문지
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• 제18권2호
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• pp.329-335
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• 2023

타임지가 선정한 슈퍼푸드이며, 후숙 과일 중 하나인 아보카도는 현지가격과 국내 유통 가격이 크게 차이가 나는 식품 중 하나이다. 이러한 아보카도의 분류과정을 자동화한다면 다양한 분야에서 인건비를 줄여 가격을 낮출 수 있을 것이다. 본 논문에서는 아보카도의 데이터셋을 크롤링을 통하여 제작하고, 딥러닝 기반 전이학습모델을 다수 사용하여, 최적의 분류모델을 만드는 것을 목표로 한다. 실험은 제작한 데이터셋에서 분리한 데이터셋에서 딥러닝 기반 전이학습모델에 직접 대입하고, 해당 모델의 하이퍼 파라미터를 Fine-tuning하며 진행하였다. 제작된 모델은 아보카도의 이미지를 입력하였을 때, 해당 아보카도의 익은 정도를 99% 이상의 정확도로 분류하였으며, 아보카도 생산 및 유통가정의 인력감소 및 정확성을 높일 수 있는 데이터셋 및 알고리즘을 제안한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.334-334
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• 2022

Improvement of old-fashioned rain gauge systems for automatic, timely, continuous, and accurate precipitation observation is highly essential for weather/climate prediction and natural hazards early warning, since the occurrence frequency and intensity of heavy and extreme precipitation events (especially floods) are recently getting more increase and severe worldwide due to climate change. Although rain gauge accuracy of 0.1 mm is recommended by the World Meteorological Organization (WMO), the traditional rain gauges in both weighting and tipping bucket types are often unable to meet that demand due to several existing technical limitations together with higher production and maintenance costs. Therefore, we aim to introduce a newly developed and cost-effective hybrid rain gauge system at 0.1 mm accuracy that combines advantages of weighting and tipping bucket types for continuous, automatic, and accurate precipitation observation, where the errors from long-term load cells and external environmental sources (e.g., winds) can be removed via an automatic drainage system and artificial intelligence-based data quality control procedure. Our rain gauge system consists of an instrument unit for measuring precipitation, a communication unit for transmitting and receiving measured precipitation signals, and a database unit for storing, processing, and analyzing precipitation data. This newly developed rain gauge was designed according to the weather instrument criteria, where precipitation amounts filled into the tipping bucket are measured considering the receiver's diameter, the maximum measurement of precipitation, drainage time, and the conductivity marking. Moreover, it is also designed to transmit the measured precipitation data stored in the PCB through RS232, RS485, and TCP/IP, together with connecting to the data logger to enable data collection and analysis based on user needs. Preliminary results from a comparison with an existing 1.0-mm tipping bucket rain gauge indicated that our developed rain gauge has an excellent performance in continuous precipitation observation with higher measurement accuracy, more correct precipitation days observed (120 days), and a lower error of roughly 27 mm occurred during the measurement period.

• 스마트미디어저널
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• 제12권11호
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• pp.18-26
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• 2023

빌딩에너지관리시스템(BEMS: Building Energy Management System)은 생산 및 소비되는 에너지를 효율적으로 관리하는 시스템이다. 그러나 건물 내 전력소비는 물리적인 특성상으로 인해 생산 및 소비가 일정하지 않아 안정적인 전력 공급이 필수적이다. 이에 따라 건물의 안정적인 전력 공급을 위해서는 정확한 건물 내 전력 소비 예측이 중요하다. 최근에는 시계열분석, 통계분석, 인공지능 등 다양한 방법을 이용하여 전력소비예측에 관한 연구가 진행되고 있다. 본 논문은 Prophet 모델의 장점과 단점을 분석하여 장점인 growth, seasonality, holidays를 선택하였고, Prophet 모델의 단점인 데이터의 복잡성과 외부변수(기후 데이터)의 제한성을 해결하기 위하여 GRU을 조합하여 단기(2일) 및 중기(7일, 15일, 30일) 전력소비량 예측 알고리즘을 제안한다. 실험결과, 제안한 방법은 기존 GRU 및 Prophet 모델보다 성능이 우수하였다.

• Animal Bioscience
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• 제37권7호
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• pp.1289-1302
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• 2024

Objective: There is a strong relationship between the content of beneficial fatty acids in milk and milk fat metabolic activity in the mammary gland. To improve milk quality, it is therefore necessary to study fatty acid metabolism in bovine mammary gland tissue. In adipose tissue, peroxisome proliferator-activated receptor gamma (PPARG), the core transcription factor, regulates the fatty acid metabolism gene network and determines fatty acid deposition. However, its regulatory effects on mammary gland fatty acid metabolism during lactation have rarely been reported. Methods: Transcriptome sequencing was performed during the prelactation period and the peak lactation period to examine mRNA expression. The significant upregulation of PPARG drew our attention and led us to conduct further research. Results: According to bioinformatics prediction, dual-luciferase reporter system detection, real-time quantitative reverse transcription polymerase chain reaction and Western blotting, miR-130a and miR-130b could directly target PPARG and inhibit its expression. Furthermore, triglyceride and oil red O staining proved that miR-130a and miR-130b inhibited milk fat metabolism in bovine mammary epithelial cells (BMECs), while PPARG promoted this metabolism. In addition, we also found that the coexpression of miR-130a and miR-130b significantly enhanced their ability to regulate milk fat metabolism. Conclusion: In conclusion, our findings indicated that miR-130a and miR-130b could target and repress PPARG and that they also have a functional superposition effect. miR-130a and miR-130b seem to synergistically regulate lipid catabolism via the control of PPARG in BMECs. In the long-term, these findings might be helpful in developing practical means to improve high-quality milk.

• 한국전자파학회논문지
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• 제26권2호
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• pp.135-147
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• 2015

전자 산업에서의 소형화와 디지털화에 따라 적층 세라믹 커패시터(Multi-Layer Ceramic Capacitors: MLCC) 또한 DC Blocking, 디커플링, 필터링 등의 기능이 이에 부응하여 그 수요가 꾸준히 증가해왔다. 이에 따라 MLCC의 등가회로를 모델링하는 기법이 많이 연구되었는데, 지금까지의 연구를 살펴보면 대부분이 소자의 주파수 특성을 측정한 후, 그 결과를 바탕으로 소자를 모델링하므로 제작 과정과 측정 과정에서 물질적, 시간적 손실을 수반한다. 이를 해결하기 위한 방법으로 본 논문에서는 구조 정보와 물질 정보로부터 설계단계에서 MLCC의 임피던스 특성을 예측할 수 있는 모델링 방법을 제시한다. 미분 방정식으로 표현되는 결합 전송선로 방정식으로부터 임의의 N개 층을 가지는 다층 평판 커패시터(N-Layer Capacitor)의 임피던스를 구조 정보와 물질 정보의 수식으로 표현할 수 있음을 보였다. 이렇게 정의된 임피던스 수식으로부터 임의의 구조 정보와 물질 정보를 가지는 MLCC의 임피던스를 예측하였으며, EM 시뮬레이션 결과와 비교하였다. 그 결과, 제시한 임피던스 예측 모델링 결과와 측정 결과가 잘 일치하였고, EM 시뮬레이션보다 훨씬 빠르게 예측 결과를 얻을 수 있음을 보였다.