• Journal of Wind Energy
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• v.5 no.1
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• pp.22-32
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• 2014

The structural design of a wind turbine must show the verification of the structural integrity of all load-carrying components. Also, design load calculations shall be performed using appropriate and accurate methods. In this study, advanced numerical approach for the calculation of design loads based on unsteady computational fluid dynamics (CFD) is presented considering extreme design load conditions such as the extreme coherent gust (ECG) and the 50 year extreme operating gust (EOG). Unsteady aerodynamic loads are calculated based on Reynolds average Navier-Stokes (RANS) equations with shear-stress transport k-ω(SST k-ω) turbulent model. A full three-dimensional 5 MW offshore wind-turbine model with rotating blades, hub, nacelle, and tower configuration is practically considered and its aerodynamic interference effect among blades, nacelle, and tower is also accurately considered herein. Calculated blade loads based on unsteady CFD method with respect to blade azimuth angle are compared with those by NREL FAST code and physically investigated in detail.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.433-435
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• 2023

본 연구는 기업가정신 글로벌비즈니스 세미나 과목의 과제로써 기업가정신이 무엇인지 확립하고 기업가정신과 연관 지을 수 있는 주제를 선정하여 스스로 연구함으로써 그 의미를 구체화 하고 새로운 패러다임을 제시하고자 하는데 의미가 있다고 볼 수 있다. 저자들은 '문화'가 갖는 상대성에 주목하여 기업가 정신을 해석하였으며 재학 중 배웠던 '홉스테드의 문화 특성' 이론과 접목시켜 문화가 기업가 정신에 어떤 영향을 끼치는지 연구하였다. 글로벌 기업가정신 모니터(GEM)의 글로벌 기업가 지수 순위 조사 결과와, 홉스테드 인사이트(Hofstede-insight)의 6가지 차원에 따른 국가별 문화지수 파일을 접목시켜 수치화하고, 시각적 그래프 및 엑셀 데이터 다중 회귀분석을 통하여 결과를 도출하였다. 홉스테드의 문화 특성이 기업가 정신 순위에 영향을 미칠 것이라고 가정하고 분석한 결과, 홉스테드의 6가지 차원 중 하나인 불확실성 회피성향이 기업가 정신에 가장 높은 영향을 미친다는 사실을 발견하였다. 이번 연구를 통해기업가 정신을 계승하는 기업문화를 제고하고 경제학과 인류학 통합 연구의 필요성을 제시한다.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.244-249
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• 2021

A 53-year-old woman presented with dyspnea. She had undergone extended thymectomy for an invasive thymoma two months prior. CT revealed numerous small nodules in the lung. After that, she deteriorated owing to acute respiratory distress syndrome (ARDS), and the vascular surgeon planned veno-venous extracorporeal membrane oxygenation (ECMO). During percutaneous cannulation through the left femoral vein, a vascular injury was suspected, and the patient's vital signs became unstable. Diagnostic angiography showed a ruptured left common iliac vein, and the bleeding was stopped by placement of a stent-graft. May-Thurner syndrome was diagnosed on abdominal CT. Here, we report a rare case of ECMO-related vascular injury in a patient with an unrecognized anatomical variant, May-Thurner syndrome.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.97-106
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• 2024

This study utilized the non-invasive MyotonPRO^® device to analyze the stiffness in breast muscles of commercial broilers (Ross 308 and Arbor Acres) and compared these findings with data reported for Ross 708, where Woody Breast (WB) symptoms had been previously documented. The research revealed that Ross 308 and Arbor Acres displayed relatively lower stiffness values compared to Ross 708, suggesting a lack of WB expression. These results indicate differentiation in breast muscle traits across strains and underscore the necessity for further research into factors influencing WB manifestation. The study also measured additional muscle tone characteristics such as Frequency, Decrement, Relaxation, and Creep across various growth stages (2, 4, 6, and 8 weeks), finding significant variations with pronounced severity at weeks 2 and 8. An increase in stiffness was observed as the broilers aged, pointing to potential growth-related or stress-induced changes affecting WB severity. A strong positive correlation was established between increased breast meat weight and WB severity, highlighting that heavier breast meat could exacerbate the condition. This correlation is vital for the poultry industry, suggesting that weight management could help mitigate WB effects. Moreover, the potential for genetic selection and breeding strategies to reduce WB occurrence was emphasized, which could aid in enhancing management practices in commercial poultry production. Collectively, these insights contribute to a deeper understanding of WB in broilers and propose avenues for future research and practical strategies to minimize its impact.

• Journal of the Korean Dietetic Association
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• v.28 no.3
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• pp.205-217
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• 2022

School meals are prepared based using the HACCP system, which is designed to ensure the physical and mental health of students. However, operational recommendations in school cafeterias have changed due to COVID-19 and include delays in serving time to restrict the number of meals and the installation of screens to prevent droplet transmission. Unfortunately, these changes may have detrimentally affected hygiene practices and generated new food poisoning sources. This study aimed to determine the hygiene state of school cafeterias in the Gyeongnam area from December 2020 to September 2021 based on the monitoring of total aerobic and coliform bacteria. Kitchen floors were the most contaminated areas with an average number of total aerobic bacteria of 4.3 log CFU/100 cm², whereas counts in dining areas were relatively low at 0.1~3.5 log CFU/100 cm². Newly installed partitioned areas had the lowest contamination level of 0.1~2.8 log CFU/100 cm². Escherichia coli was not detected on any surface, while coliform was detected on workbenches and floors. In conclusion, hygienic practices appear to have been adequately managed in school cafeterias despite COVID-19 driven changes. Nonetheless, continuous monitoring is recommended to ensure prompt response to changing environments.

• Proceedings of the Petrological Society of Korea Conference
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• 2009.05a
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• pp.166-166
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• 2009

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.208-208
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• 2018

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.92-92
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• 2021

• Economic and Environmental Geology
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• v.33 no.4
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• pp.249-260
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• 2000

The development of dual volcanic chains, parallel to the trend of the subduction trench, is observed in the southern part of Korea. Elsewhere on the Earth volcanic arcs dominantly consist of two such chains. In the southern part of Korea, two volcanic chains within a single volcanic arc was developed. Kyongsang basin, where the first volcanic chain located, and Youngdong-Kwangju depression zone where the second volcanic zone located, showed sub-parallel volcanic rock distributed areas. Concentrations of incompatible elements in the southern part of Korea samples show clear across-arc variations, with lavas from the first volcanic chain being most depleted in these elements, all incompatible element concentrations increase towards the second volcanic chain. The above across-arc variation may be caused by the difference in solid phases coexisting with the fluid phases during the dehydration processes. The concentrations of incompatible elements, Zr/Y ratios, and Rb/K ratios indicate that the second volcanic chain (Youngdong-Kwangiu depression zone) was generated by low degrees of partial melting at the deeper depth compared to the conditions of the first volcanic chain (Kyongsang basin) and residual garnet probably attributed to the their partial melting.

• Transactions of Materials Processing
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• v.31 no.4
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• pp.173-178
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• 2022

The present study employed two different machine-learning approaches, the extreme gradient boosting (XGB) and light gradient boosting machine (LGBM), to predict a compressive deformation behavior of additively manufactured Ti-6Al-4V. Such approaches have rarely been verified in the field of metallurgy in contrast to artificial neural network and its variants. XGB and LGBM provided a good prediction for elongation to failure under an extrapolated condition of processing parameters. The predicting accuracy of these methods was better than that of response surface method. Furthermore, XGB and LGBM with optimum hyperparameters well predicted a deformation behavior of Ti-6Al-4V additively manufactured under the extrapolated condition. Although the predicting capability of two methods was comparable, LGBM was superior to XGB in light of six-fold higher rate of machine learning. It is also noted this work has verified the LGBM approach in solving the metallurgical problem for the first time.