• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.107-117
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• 2021

The purpose of this study is to provide basic data for the development of UV protection products using natural materials. The research method is investigation and analyzation of the current status of the domestic and foreign industries, natural material research trends, and patent status of skin care-related sunscreen. As the result of the study, the U.S. market for sunscreen is the largest one, accounting for about 21% of the world, and the Chinese market is rapidly growing. The top four major types of functional cosmetics in Korea are complex functional products, followed by wrinkle improvement, sunscreen and whitening, and both the global and domestic markets continue to grow continuously. Over the past decade, research trends in natural sunscreen materials have shown that Scutellaria baicalensis, Humulus lupulus L., licorice, Finger root, Green tea, lespedeza cuneata extracts are effective, and in addition, they are also effective in photo-aging, antioxidant, anti-inflammatory, antibacterial, whitening, and wrinkle improvement. The patent registration status is on the rise and the ingredients were secured from plants and seaweeds. As the conclusion of this research, It is expected that natural UV protection material will be able to be used as multi-functional cosmetics material by developing safe and proven natural materials in line with future global trends.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.81-99
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• 2022

The Baekdudaegan, spanning around 701 km from Hyangrobong to Cheonwangbong of Mt. Jirisan in South Korea, is rich in biodiversity and known as the main ecological axis of the Korean Peninsula. The Neuljae-Yuksimnyeong section of Marugeum in the southern part of the Baekdudaegan, particularly Mt. Deogyusan, is an area in which various types of vegetation appear depending on the environmental characteristics. The aims of this study were to investigate the current vegetation status at the Neuljae-Yuksimnyeong section of the Baekdudaegan and to provide basic data to aid systematic conservation and management through future classification of forest vegetation types. A vegetation survey was conducted using 637 plots from May to October 2019. Vegetation-type analysis showed that the vegetation units could be classified as a Quercus mongolica community group divided into seven communities: the Abies koreana community, Sanguisorba hakusanensis community, Persicaria hydropiper community, Quercus variabilis community, Quercus dentata community, Cornus controversa community, and Quercus mongolica community. The A. koreana community was subdivided into the Dryopteris expansa group and Picea jezoensis group. The Q. variabilis community was also subdivided into the Q. dentata group and Q. variabilis typical group. We concluded that special management plans for distinctive forest vegetation, including subalpine vegetation, grass or herb vegetation, and agricultural vegetation, should be prepared urgently to aid ecosystem preservation and enhancement.

• Journal of Life Science
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• v.32 no.1
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• pp.51-55
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• 2022

Matrix metalloproteinase (MMP) enzymes are responsible for the degradation and formation of the extracellular matrix (ECM), and overproduction of MMPs is observed in several diseases, such as cancer and asthma, that progress with metastatic characteristics. Natural products, especially phytochemicals, have been an important source of MMP inhibitors with reduced side effects. Although the majority of phytochemicals inhibit the enzymatic activity of MMPs, some suppress MMP production. In this context, the current study evaluated the potential of Corydalis heterocarpa, a halophyte with reported bioactivities, to inhibit MMP expression in PMA-stimulated HT-1080 cells. A crude C. heterocarpa extract was shown to decrease the mRNA and protein expression of MMP-2 and MMP-9 while increasing the endogenous MMP inhibitors TIMP-1 and TIMP-2 which regulate MMP expression in healthy tissues. In addition, our results show that the inhibitory effects of C. heterocarpa might occur through suppression of the phosphorylation of MAPK signaling, the upstream activator of MMP overexpression. In conclusion, C. heterocarpa is a potential source of antimetastatic compounds that might serve as lead molecules to develop novel MMP inhibitors.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.115-130
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• 2022

Barrage is an interactive method based on video, and the video itself is visualized from the viewer's point of view to play people's emotions, and it already has an advantage in communication by attracting people's attention using stories and plays. Advances in digital and mobile technology have enabled video viewing anytime, anywhere. Due to the nature of the barrage site that relies on the same video content or playback to participate in video sharing through computers or mobile clients, a barrage that can express users' feelings and thoughts will be added, breaking down the limit of content acceptance by a single user. Barrage satisfy users' entertainment needs, and their influence is growing. Gradually, they are heading to offline movie theaters and TV from barrage videos on the Internet. Attempts to function as offline ammunition facilitated technological innovation for media convergence by converging mobile media with PCs and screens. At the same time, the trend of media convergence shown by coal screens is also a trend of overall technological development. A barrage is an extension of human communication skills. The properties of the barrage fit well with the need for experiential marketing (via video). It can provide a visual experience and create an atmosphere of "surrounding and watching" and eliminate loneliness. Barrage itself provides a function to comment on videos, which is a trigger point for the reason, and donation adds to the amount of information in the video, adding to the fun of the video. Through the barrage, sarcastic, teasing, and expressing emotions can bring entertainment experiences, and users can produce and communicate their shooting text while consuming the satisfaction brought by the shooting. At the same time, Barrage attaches great importance to the needs of the masses, is more individual and diversified, and has commercial significance in line with the current development trend of the Internet. As a new interactive method, barrage contains huge potential value. However, the impact of the interactive way of barrage should also be viewed from a dialectical point of view, how to solve the difficulties in the development of barrage. The way to solve the difficulties in the development of barrage is worth studying. This research will analyze the reasons for the development of barrage and the analysis of Chinese barrage websites, the case analysis of barrage videos, the exploration of the characteristics and values of barrage, and the problems in the process of barrage communication. Provide reference for the development of industrial culture.

• Journal of Biomedical Engineering Research
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• v.43 no.1
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• pp.52-60
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• 2022

Purpose: For now, cognitive load is assessed based on survey-based methods, which can be difficult to track the amount of cognitive load in real-time. In this study, we investigated the difference in electrophysiological activation due to different levels of cognitive load not only at sensor-level but also at source-level using electroencephalogram that might be potentially used for quantitative cognitive load evaluation. Materials and Methods: In this study, ten healthy subjects (mean age 24.3 ± 2.1, three female) participated the experiment. All participants performed 4 sessions of n-back task in different difficulties: 0-, 1-, 2-, and 3-back during electroencephalogram recording. For sensor-level analysis, we calculated the event-related potential and event-related spectral perturbation while low resolution brain electromagnetic tomography (LORETA) to estimate the source activation. Each result was compared between different workload conditions using statistical analysis. Results: Statistical results revealed that the accuracy of the task performance was significantly different between different cognitive loads (p = 0.018). The post-hoc analysis confirmed that the accuracy of the 3-back task was significantly decreased compared to 1-back condition (p = 0.018), but not with 2-back condition (p = 0.180). ERP results showed that P300 target amplitude between 1-back and 3-back had a marginal difference in Cz (p = 0.059) and Pz(p = 0.093). A significant inhibition in Cz high-beta activation (p = 0.017) and decrease in source activation of right parahippocampal gyrus was found in 3-back condition compared to 1-back condition (p < 0.05). Conclusion: In this study, we compared the sensor- and source-level differences in electroencephalogram between different levels of cognitive load, that were found to be in line with the previous reports related to cognitive load evaluation. We expect that the outcome of the current study can be used as a feature to establish a quantitative cognitive load assessment system.

• Journal of Conservation Science
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• v.38 no.3
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• pp.201-216
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• 2022

Materials and techniques used for two portraits (Jo-nyeon Lee and S ung-in Lee) of the Lee family from Seongju enshrined in Seongsan temple were scientifically analyzed, and based on the data, an optimal replica restoration method was designed. According to the expression technique investigation, both portraits were expressed mainly in line drawing, but there were differences in shoes, pupils, the color expression of flesh, overpainting, and traces of reinforcement. Pigment analysis revealed that a mixture of cinnabar and minium, organic pigment, azurite, malachite, lead white, and yellow pigment were used in common. In the case of Sung-in Lee's portrait, seokganju and atacamite were also used. In addition, comparison with the contemporaneous portraits of gentry showed that the portrait style at the time was found in the two portraits, but the singularity was modified differently there. Based on the scientific analysis, it was decided to replicate the old color restoration for Jo-nyeon Lee's portrait while for Sung-in Lee's portrait, it was decided to replicate the phenomenon. Detailed coloring techniques were presented by supplementing the expression techniques that are difficult to confirm visually using scientific data. In addition, by measuring the chromaticity of representative positions in the portrait for each color and presenting the color reference value calculated as the average value, the current color of the artifact can be replicated and restored based on the objective data as much as possible.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.62-72
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• 2022

In this study, a miniaturized GPS band(L₁ : 1.575 GHz) antenna that can be mounted on a small drone is proposed. The miniaturization was designed by applying the perturbation method based on the λ/4 microstrip antenna and lengthening the current path at the edge of the patch. The miniaturized antenna was fabricatred such that it could be attached to the surface of styrofoam(ε_r=1.06, t=10 mm) having a size of 10 mm × 9 mm × 10 mm (0.05 λ × 0.05 λ × 0.05 λ). The thickness and length of the feeding line and the spacing between short stubs were adjusted for impedance matching. S₁₁ was found to be -18.8 dB at the center frequency of the fabricated antenna, 1.575 GHz. The radiation pattern measurement results show that the maximum gain of E_θ is 1.87 dBi in 0 directions in the xz-plane, and that E_θ is an omnidirectional characteristic with an average gain of -1.7 dBi in the yz-plane. It was found that the antenna can be used as an ultra-small microstrip antenna, which can be mounted on a small dron for GPS, and is capable of preserving a reduction ratio of 98.8% as compared to a λ/2 microstrip patch antenna.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.238-247
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• 2023

Liquefied petroleum gas (LPG) is an attractive fuel for ships considering its current technology and economic viability. However, safety guidelines for LPG-fueled ships are still under development, and there have been no cases of applying LPG propulsion systems to small and medium-sized ships in Korea. The purpose of this study was to perform an objective risk assessment for the first marine LPG engine system and propose safe operational standards. First, hazard and operability (HAZOP) analysis was used to divide the engine system into five nodes, and 58 hazards were identified. To compensate for the subjectivity of qualitative evaluation using HAZOP analysis, fuzzy set theory was used, and additional risk factors, such as detectability and sensitivity, were included to compare the relative weights of the risk factors using a fuzzy analytical hierarchy process. As a result, among the five risk factors, those with a major impact on risk were determined to be the frequency and severity. Finally, the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) was applied to select the risk rank more precisely by considering the weights of the risk factors. The risk level was divided into 47 groups, and the major hazard during the operation of the engine system was found through the analysis to be gas leakage during maintenance of the LPG supply line. The technique proposed can be applied to various facilities, such as LPG supply systems, and can be utilized as a standard procedure for risk assessment in developing safety standards for LPG-powered ships.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.227-233
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• 2023

Along with the 4th Industrial Revolution, the impact of "unmanned" is affecting all fields around the world, and in particular, in the military sector, "unmanned" is so important that it occupies a part of the main combat system. Recently, the South Korean military is facing a crisis due to the North Korea's UAV incident that invaded our airspace and descended to Seoul. In response, the South Korea military declared its willingness and countermeasures to capture and destroy North Korea's UAV. However, as the technological development of UAV continues and the utilization plan is expanding, the countermeasures for UAV at the current level can be useless. Also, the threat from North Korea is not just UAV. North Korea has practically a nuclear power and is set to conduct its seventh nuclear test, and its missile technology is also being advanced, with 38 arounds of 67 missile tests conducted in 2022 alone. It is also developing five key strategic weapons that can pose a fatal threat to Korea, and North Korea's strong conventional forces are located around the NLL(Northern Limit Line), and the port of Long Range Artillery is facing the Seoul metropolitan area. It is important to respond to North Korea's UAV threats, which are now receiving much attention, but it will be necessary to comprehensively analyze and clearly prioritize North Korea's threats and use a limited budget to respond to them.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.121-131
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• 2023

The Chinese three northeastern three provinces - Heilongjiang, Liaoning, and Jilin - hold significant geographical, geopolitical, and commercial importance due to their location allowing for cross-border trade and transportation with North Korea. These provinces are crucial for establishing a complex Eurasian logistics network in line with South Korea's new northern policy. The Chinese three northeastern three provinces, as this region is known, boasts excellent maritime transportation links between South Korea, China, and North Korea, making it an logistics hub for transporting goods to Eurasia and Europe through multimodal transport. This study highlights the importance of securing a logistics hub area by fostering cooperation and friendly relations with China's three northeastern three provinces, which are crucial to the success of the New Northern Policy. In particular, the study aims to analyze current status of trade with these region and freight volume transported by ships and recommend political advice for securing logistics hub and revitalizing maritime transport. As the policy suggestion, this study is to establish a logistics hub by implementing joint port operations, constructing port infrastructure jointly, and operating shipping companies together. Additionally, we propose ways to revitalize the maritime passenger transport business between Korea and China, which involves expanding cultural exchanges and developing content.