• 천문학회지
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• 제55권2호
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• pp.23-36
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• 2022

We present a method to determine nitrogen abundance ratios with respect to iron ([N/Fe]) from molecular CN-band features observed in low-resolution (R ~ 2000) stellar spectra obtained by the Sloan Digital Sky Survey (SDSS) and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Various tests are carried out to check the systematic and random errors of our technique, and the impact of signal-to-noise (S/N) ratios of stellar spectra on the determined [N/Fe]. We find that the uncertainty of our derived [N/Fe] is less than 0.3 dex for S/N ratios larger than 10 in the ranges T_eff = [4000, 6000] K, log g = [0.0, 3.5], [Fe/H] = [-3.0, 0.0], [C/Fe] = [-1.0, +4.5], and [N/Fe] = [-1.0, +4.5], the parameter space that we are interested in to identify N-enhanced stars in the Galactic halo. A star-by-star comparison with a sample of stars with [N/Fe] estimates available from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) also suggests a similar level of uncertainty in our measured [N/Fe], after removing its systematic error. Based on these results, we conclude that our method is able to reproduce [N/Fe] from low-resolution spectroscopic data, with an uncertainty sufficiently small to discover N-rich stars that presumably originated from disrupted Galactic globular clusters.

• 대한한방부인과학회지
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• 제34권3호
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• pp.15-28
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• 2021

Objectives: This study was designed to examine the anti-cancer activity by innate immunomodulating and anti-inflammatory effects of liriopis tuber water extract (LPE). Methods: Cell cytotoxicity was tested with 4T1 mouse mammary carcinoma cells, spleen cells, macrophage, and RAW264.7 cells. To investigate innate immunomodulating effects of LPE on macrophage, we measured tumor necrosis factor-alpha (TNF-α), interleukin-12 (IL-12), and interleukin-10 (IL-10). To investigate innate immunomodulating effects of LPE on RAW264.7 cell, we measured TNF-α, interleukin-6 (IL-6). In addition, TNF-α and nitric oxide (NO) induced by lipopolysaccharide (LPS) were measured after treating with LPE to observe innate immunomodulating effect of LPE on RAW264.7 cell. Also, mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) were examined by western blot analysis. Results: In an in vitro cytotoxicity analysis, LPE affected tumor cell growth above specific concentration. As compared with the control group, the production of TNF-α, IL-12, and IL-10 were increased in macrophage. As compared with the control group, the production of TNF-α and IL-6 were increased in RAW 264.7 cell. The expression of TNF-α and NO induced by LPS after treating LPE was decreased. In addition, treatment of RAW 264.7 cell with LPE increased the phosphorylation levels of p-extracellular signal-regulated kinase (p-ERK), p-Jun N-terminal kinase (p-JNK), and p-p38. Conclusions: LPE might have impact on the anti-cancer effect by activation of innate immune system and inflammation control.

• 한국안전학회지
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• 제37권6호
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• pp.102-107
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• 2022

South Korea will soon be a super-aged society, as more than 20.6% of its population will be 65 years and older by 2025. As of 2022, 17.5% of the total population in South Korea is 65 years and older, which exceeds the set threshold for an aged society, where more than 14% of the population is 65 years and older. The proportion of older subway construction workers has increased. Aging workers and their work stress negatively impact their workability. A previous study demonstrated that the stress index measured using the uBioMacpa measurement device (Macpa stress index) had a significant correlation with work stress in South Korea. The device tests vascular health and measures stress levels via Macpa signal analysis. In this study, the pulse waves of subway construction workers were measured using uBioMacpa to identify their stress levels. The stress levels were analyzed by age, years of service, job position, employment type, and work type. Herein, these statistics could not be easily represented by a normal distribution; therefore, the Kruskal-Wallis test, a nonparametric statistical method, was used for the analysis of data. The results showed that age, job position, employment type, and working type affected the Macpa stress index and the stress levels of workers increased with age. In terms of job position, technical engineers were more stressed than other workers because of their poor working environment. In terms of employment type, daily-wage workers were more stressed than other workers. In terms of working type, tunneling, waterproofing, and construction scored the highest Macpa stress indexes without any significant difference, whereas earthworks scored the lowest. Based on the analysis of Macpa stress index, safety and health management plans were proposed to reduce the stress levels of workers. Moreover, a manual for efficient stress management must be developed for subway construction workers.

• 대한의용생체공학회:의공학회지
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• 제44권2호
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• pp.118-124
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• 2023

Many recent studies have reported that the quality of input learning data was vital to the detection of regions of interest. However, due to a lack of research on the quality of learning data on lesion detetcting using gastroscopy, we aimed to quantify the impact of quality difference in endoscopic images to lesion detection models using Image Quality Assessment (IQA) algorithms. Through IQA methods such as BRISQUE (Blind/Referenceless Image Spatial Quality Evaluation), Laplacian Score, and PSNR (Peak Signal-To-Noise) algorithm on 430 sheets of high quality data (HQD) and 430 sheets of low quality data (PQD), we showed that there were significant differences between high and low quality images in lesion detecting through BRISQUE and Laplacian scores (p<0.05). The PSNR value showed 10.62±1.76 dB on average, illustrating the lower lesion detection performance of PQD than HQD. In addition, F1-Score of HQD showed higher detection performance at 77.42±3.36% while F1-Score of PQD showed 66.82±9.07%. Through this study, we hope to contribute to future gastroscopy lesion detection assistance systems that involve IQA algorithms by emphasizing the importance of using high quality data over lower quality data.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1242-1242
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• 2022

Annually, several construction workers fall ill, are injured, or die due to heat-related exposure. The prevalence of work-related heat illness may rise and become an issue for workers operating in temperate climates, given the increase in frequency and intensity of heatwaves in the US. An increase in temperature negatively impacts physical exertion levels and mental state, thereby increasing the potential of accidents on the job site. To reduce the impact of heat stress on workers, it is critical to develop and implement measures for monitoring physical exertion levels and mental state in hot conditions. For this, limited studies have evaluated the utility of wearable biosensors in measuring physical exertion and mental workload in hot conditions. In addition, most studies focus solely on male participants, with little to no reference to female workers who may be exposed to greater heat stress risk. Therefore, this study aims to develop a process for objective and continuous assessment of worker physical exertion and mental workload using wearable biosensors. Physiological data were collected from eight (four male and four female) participants performing a simulated drilling task at 92oF and about 50% humidity level. After removing signal artifacts from the data using multiple filtering processes, the data was compared to a perceived muscle exertion scale and mental workload scale. Results indicate that biosensors' features can effectively detect the change in worker physical and mental state in hot conditions. Therefore, wearable biosensors provide a feasible and effective opportunity to continuously assess worker physical exertion and mental workload.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4431-4440
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• 2022

An advanced nuclear reactor based on molten salts including a molten salt reactor and pyroprocessing needs a sensitive monitoring system suitable for operation in harsh environments with limited access. Multi-element detection is challenging with the conventional technologies that are compatible with the in-situ operation; hence laser-induced breakdown spectroscopy (LIBS) has been investigated as a potential alternative. However, limited precision is a chronic problem with LIBS. We increased the precision of LIBS under high temperature by protecting optics using a gas protective layer and correcting for shotto-shot variance and lens-to-sample distance using a laser-induced acoustic signal. This study investigates cerium as a surrogate for uranium and corrosion products for simulating corrosive environments in LiCl-KCl. While the un-corrected limit of detection (LOD) range is 425-513 ppm, the acoustic-corrected LOD range is 360-397 ppm. The typical cerium concentrations in pyroprocessing are about two orders of magnitude higher than the LOD found in this study. A LIBS monitoring system that adopts these methods could have a significant impact on the ability to monitor and provide early detection of the transient behavior of salt composition in advanced molten salt-based nuclear reactors.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.485-491
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• 2023

As an auxiliary tool for fixing the patient's posture when taking an X-ray, sponges with high radiolucencies are laminated in various thicknesses. This study aimed to evaluate the usefulness of an auxiliary tool for hand oblique projection X-ray by manufacturing it with a uniform thickness by 3D printing and comparing it with existing sponge tools. In the auxiliary tool, radiolucency was measured at the stairs where each finger was located, and pixel information values were compared in the digital imaging and communications in medicine(DICOM) image. Contrast to noise ratio(CNR) and signal to noise ratio(SNR) were compared by shooting the hand phantom and the auxiliary tool together. As the thickness of the sponge tool increased, radiolucency decreased by 15.52% and pixel information value increased by 20.61%. The transmittance of the 3D printing tool increased by 0.82%, and the pixel information value differed by 5.66%. CNR and SNR increased by 20.03% and 22.42% in 3D printing compared to existing sponge tools. while taking hand oblique projection, maintaining the thickness of the auxiliary tool uniformly through 3D printing maintains high radiolucency and minimal impact on medical images, and increases CNR and SNR, making it useful as an auxiliary tool for taking hand oblique projection.

• Nutrition Research and Practice
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• 제17권6호
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• pp.1070-1083
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• 2023

BACKGROUND/OBJECTIVES: Sanghuangporus sanghuang (SS) has various medicinal effects, including anti-inflammation and anticancer activities. Despite the extensive research on SS, its molecular mechanisms of action on lung cancer are unclear. This study examined the impact of an SS alcohol extract (SAE) on lung cancer using in vitro and in vivo models. MATERIALS/METHODS: Different concentrations of SAE were used to culture lung cancer cells (A549 and H1650). A cell counting kit-8 assay was used to detect the survival ability of A549 and H1650 cells. A scratch assay and transwell cell invasion assay were used to detect the migration rate and invasive ability of SAE. Western blot analysis was used to detect the expression of B-cell lymphoma-2 (Bcl-2), Bcl2-associated X (Bax), cyclin D1, cyclin-dependent kinases 4 (CDK4), signal transducer and activator of transcription 3 (STAT3), and phosphorylated STAT3 (p-STAT3). Lung cancer xenograft mice were used to detect the inhibiting ability of SAE in vivo. Hematoxylin and eosin staining and immunohistochemistry were used to detect the effect of SAE on the structural changes to the tumor and the expression of Bcl-2, Bax, cyclin D1, CDK4, STAT3, and p-STAT3 in lung cancer xenograft mice. RESULTS: SAE could inhibit lung cancer proliferation significantly in vitro and in vivo without cytotoxicity. SAE suppressed the viability, migration, and invasion of lung cancer cells in a dose and time-dependent manner. The SAE treatment significantly decreased the proapoptotic Bcl-2/Bax ratio and the expression of pro-proliferative proteins Cyclin D1 and CDK4 in vitro and in vivo. Furthermore, SAE also inhibited STAT3 expression. CONCLUSIONS: SAE reduced the cell viability and suppressed cell migration and invasion in human lung cancer cells. Moreover, SAE also exhibited anti-proliferation effects in vivo. Therefore, SAE may have benefits in cancer therapy.

• 정보보호학회논문지
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• 제34권2호
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• pp.217-228
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• 2024

자율주행 자동차의 안전한 운행을 위해 카메라, RADAR(RAdio Detection And Ranging), 초음파 센서 중 중추적인 역할을 하는 LiDAR(Light Detection And Ranging) 센서는 360도에서 사물을 인식하고 탐지할 수 있다. 하지만 이러한 LiDAR 센서는 레이저를 통해서 거리를 측정하기 때문에 공격자에 노출되기 쉬우며 다양한 보안위협에 직면해있다. 따라서 본 논문에서는 LiDAR 센서를 대상으로 한 여러 가지 보안 위협인 Relay, Spoofing, Replay 공격을 살펴보고 물리적 신호교란(Jamming) 공격의 가능성과 그 영향을 분석하며, 이러한 공격이 자율주행 시스템의 안정성에 미치는 위험을 분석한다. 실험을 통해, 물리적 신호교란 공격이 LiDAR 센서의 거리 측정 능력에 오류를 유발할 수 있음을 보여준다. 개발이 진행 중인 차량 간 통신(Vehicle-to-Vehicle, V2V), 다중 센서 융합과 LiDAR 비정상 데이터 탐지를 통해 이러한 위협에 대한 대응방안과 자율주행 차량의 보안 강화를 위한 기초적인 방향을 제시하고 향후 연구에서 제안된 대응방안의 실제 적용 가능성과 효과를 검증하는 것을 목표로 한다.

• 농업과학연구
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• 제51권1호
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• pp.63-77
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• 2024

Yield monitoring systems have become integral to precision agriculture, providing insights into the spatial variability of crop yield and playing an important role in modern harvesting technology. This paper aims to review current research trends in yield monitoring systems, specifically designed for non-grain crops, including cabbages, radishes, potatoes, and tomatoes. A systematic literature survey was conducted to evaluate the performance of various monitoring methods for non-grain crop yields. This study also assesses both mass- and volume-based yield monitoring systems to provide precise evaluations of agricultural productivity. Integrating load cell technology enables precise mass flow rate measurements and cumulative weighing, offering an accurate representation of crop yields, and the incorporation of image-based analysis enhances the overall system accuracy by facilitating volumetric flow rate calculations and refined volume estimations. Mass flow methods, including weighing, force impact, and radiometric approaches, have demonstrated impressive results, with some measurement error levels below 5%. Volume flow methods, including paddle wheel and optical methodologies, yielded error levels below 3%. Signal processing and correction measures also play a crucial role in achieving accurate yield estimations. Moreover, the selection of sensing approach, sensor layout, and mounting significantly influence the performance of monitoring systems for specific crops.