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아스팔트 혼합물의 골재 간극률 예측을 위한 기계학습 프레임워크
박혜민,나일호,김현환,지봉준,Hyemin Park,Ilho Na,Hyunhwan Kim,Bongjun Ji 한국지반신소재학회 2024 한국지반신소재학회 논문집 Vol.23 No.1
The Voids in the Mineral Aggregate (VMA) within asphalt mixtures play a crucial role in defining the mixture's structural integrity, durability, and resistance to environmental factors. Accurate prediction and optimization of VMA are essential for enhancing the performance and longevity of asphalt pavements, particularly in varying climatic and environmental conditions. This study introduces a novel machine learning framework leveraging ensemble machine learning model for predicting VMA in asphalt mixtures. By analyzing a comprehensive set of variables, including aggregate size distribution, binder content, and compaction levels, our framework offers a more precise prediction of VMA than traditional single-model approaches. The use of advanced machine learning techniques not only surpasses the accuracy of conventional empirical methods but also significantly reduces the reliance on extensive laboratory testing. Our findings highlight the effectiveness of a data-driven approach in the field of asphalt mixture design, showcasing a path toward more efficient and sustainable pavement engineering practices. This research contributes to the advancement of predictive modeling in construction materials, offering valuable insights for the design and optimization of asphalt mixtures with optimal void characteristics.
우라늄 제거를 위한 실험실 규모 동전기 장치의 개선 방안
박혜민,김계남,김승수,김완석,박욱량,문제권,Park, Hye-Min,Kim, Gye-Nam,Kim, Seung-Soo,Kim, Wan-Suk,Park, Uk-Ryang,Moon, Jei-Kwon 한국방사성폐기물학회 2013 방사성폐기물학회지 Vol.11 No.2
The original pilot-scale electrokinetic equipment suitable to soil contamination characteristics of Korean nuclear facility sites was manufactured for the remediation of soil contaminated with uranium. During the experiment with the original electrokinetic equipment, many metal oxides were generated and were stuck on the cathode plate. The uranium removal capability of the original electrokinrtic equipment was almost exhausted because the cathode plate covered with metal oxides did not conduct electricity in the original electrokinetic equipment. Therefore, the original electrokinetic equipment was improved. After the remediation experience for 25 days using the improved electrokinetic remediation equipment, the removal efficiency of uranium from the soil was 96.8% and its residual uranium concentration was 0.81 Bq/g. When the initial uranium concentration of soil was about 50 Bq/g, the electrokinetic remediation time required to remediate the uranium concentration below clearance concentration of 1.0 Bq/g was about 34 days. When the initial uranium concentration of soil was about 75 Bq/g, the electrokinetic remediation time required to remediate below 1.0 Bq/g was about 42 days. When the initial uranium concentration of soil was about 100 Bq/g, the electrokinetic remediation time required to remediate below 1.0 Bq/g was about 49 days. 방사능 오염 토양 복원을 위해 실험실 규모의 동전기 복원장치를 제작하여 가동 하던 중 토양 내 존재하던 금속이온의 용출로 금속 산화물이 발생하여 음극의 전류 흐름을 차단하는 문제가 발생하였다. 전류의 차단으로 토양 내 우라늄 제거 능력이 상실되어 이러한 문제를 해결하는 해결 방안을 모색하여 개선된 동전기 복원 장치를 제작하였다. 개선된 실험실 규모 동전기 복원 장치를 이용하여 토양복원 실험을 25 일간 수행 하였을 때 우라늄 잔류 농도는 0.81 Bq/g으로 약 96.8%의 제거 효율을 보였으며, 초기 우라늄 농도 50 Bq/g 일 때 우라늄 규제 해제 농도인 1 Bq/g 이하로 제거 되기 까지는 34 일의 복원 기간이 필요하고, 초기 우라늄 농도 75 Bq/g, 100 Bq/g 일 때 각 42 일, 49 일이 필요한 것으로 나타났다.
박혜민,주관식,김정호,김동성,박기현,박찬종,한우준 대한방사선방어학회 2016 방사선방어학회지 Vol.41 No.3
Background: To optimize the photon transmission effciency of light guides used in scintillation detectors, LightTools code, which can construct and track light, was used to analyze photon transmission effectiveness with respect to light guides thickness. Materials and Methods: This analysis was carried out using the commercial light guide, N-BK 7 Optical Glass by SCHOTT, as a model for this study. The luminous exitance characteristic of the LYSO scintillator was used to analyze the photon transmission effectiveness according to the thickness of the light guide. Results and Discussion: The results of the simulations showed the effectiveness of the photon transmission according to the thickness of the light guide, which was found to be distributed from 13.38% to 33.57%. In addition, the photon transmission effciency was found to be the highest for light guides of 4 mm of thickness and a receiving angle of 49°. Conclusion: Through such simulations, it is confirmed that photon transmission effciency depends on light guide thickness and subsequent changes in the internal angle of reflection. The aim is to produce an actual light guide based on these results and to evaluate its performance.
IEC 규정 노출지수를 활용한 디지털 방사선 영상시스템에서의 영상 수용체간 특성평가 (Ⅰ)
박혜민,윤용수,노영훈,김성준,나찬영,한태호,김정수,정회원,김정민 대한방사선과학회 2019 방사선기술과학 Vol.42 No.4
The International Electrotechnical Commission (IEC) has regulated the definition and requirements of the exposure index (EI). In this study, we calculated the EI of several image receptors in digital radiography system of two different manufacturers according to the method as per IEC, and evaluated the relationship with incident air kerma. To calculate t he E I, w e obtained the characteristics curve of e ach i mage receptor b y increasing t he i ncident air kerma at R QA 3, 5, 7 and 9, respectively. As a result, there was no significant difference in the EI values between different image receptors of the same manufacturer, but EI values of different manufacturer was different despite the same air kerma was incident. Therefore, understanding the characteristics of the digital radiography systems is important in order to use EI as a tool for measuring and managing the radiation dose.
박혜민,오철웅,손명호 한국통합생물학회 2012 Animal cells and systems Vol.16 No.1
The objective of the study was to investigate if reproductive characteristics of Pandalus eous affect the depth distribution in the East Sea of Korea. P. eous was found at depths of 500900 m in the East Sea of Korea, with the highest percentage occurrence (34%) at 500 m. A negative correlation was observed between the number of individuals and the depth. The overall sex ratio also turned out to be significantly correlated with depth. On average,the larger individuals (bigger than 26.37 cm), which included transitional, female, and ovigerous females, were mostly distributed at 700 m depth. The percentage of males increased by depth and ovigerous females were mainly distributed in the shallow water (300 m) during winter. Ovigerous females were not found at 900 m, which is the deepest depth range in this study. The percentage of transitional individuals was greatest at 500 m and decreased gradually with depth. All ovigerous female individuals were of the spent ovarian stage in winter. Female numbers in the ripe ovarian stage increased with depth and immature females rarely appeared. The gonadosomatic indices of the nonovigerous females and ovigerous females were highest at 700 m in depth. The mean egg size of P. eous was 0.8390.11 mm3 in the noneyed stage and 0.9390.17 mm3 in the eyed stage.