• Clean Technology
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• v.27 no.1
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• pp.17-23
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• 2021

Black polymer spacers are currently used for physically separating aligned camera lenses in camera modules of mobile phones. However, the mechanical properties of polymer spacers have their limits, especially in the current trend of using more lenses in thinner camera modules. Thus, copper (Cu) becomes a good candidate for those polymer spacers because of its superior mechanical properties and its inherent blackness due to its black surfaced oxides, such as copper (II) oxide (cupric oxide, CuO). The latter property is critical in quality control because the closer the color of a spacer is to black, the less light interference and flaring phenomena can occur. A standard Cu blackening process and its operational conditions were proposed in this study through a comprehensive analysis of previous research and patents. The Cu blackening process is composed of cleaning, deoxidizing, activating, blackening and sealing. The effects of operational parameters, such as the temperature of each unit process and the activator concentration, were then investigated by measuring the blackness of the Cu strips with a colorimeter. The proposed operational conditions were determined by whether the blackness of Cu strips was within the on-spec. value used in the field.

• Journal of Space Technology and Applications
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• v.1 no.2
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• pp.217-240
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• 2021

Upon the human exploration era of the Moon, this paper introduces lunar topography and geologic fundamentals to space scientists. The origin of scientific terminology for the lunar topography was briefly summarized, and the extension of the current Korean terminology is suggested. Specifically, we suggest the most representative lunar topography that are useful to laymen as 1 ocean (Oceanus Procellarum), 10 maria (Mare Imbrium, Mare Serenitatis, Mare Tranuillitatis, Mare Nectaris, Mare Fecundatis, Mare Crisium, Mare Vaporium, Mare Cognitum, Mare Humorum, Mare Nubium), 6 great craters (Tyco, Copernicus, Kepler, Aristachus, Stebinus, Langrenus). We also suggest Korean terms for highland, maria, mountains, crater, rille, rima, graben, dome, lava tube, wrinkle ridge, trench, rupes, and regolith. In addition, we introduce the standard model for the lunar interior and typical rocks. According to the standard model on the basis of historical impact events, the lunar geological eras are classified as Pre-Nectarian, Nectarian, Imbrian, Erathostenesian, and Copernican in chronologic order. Finally, we summarize the latest discovery records on the water on the Moon, and introduce the concept of water extraction from the lunar soil, which is to be developed by the Korea Institute of Geoscience and Mineral Resources (KIGAM).

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.695-706
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• 2022

Medium and high-resolution optical satellites have proven their effectiveness in detecting wildfire areas. However, smoke plumes generated by wildfire scatter visible light incidents on the surface, thereby interrupting accurate monitoring of the area where wildfire occurs. Therefore, a technology to extract smoke in advance is required. Deep learning technology is expected to improve the accuracy of smoke extraction, but the lack of training datasets limits the application. However, for clouds, which have a similar property of scattering visible light, a large amount of training datasets has been accumulated. The purpose of this study is to develop a smoke extraction technique using deep learning, and the limits due to the lack of datasets were overcome by using a cloud dataset on transfer learning. To check the effectiveness of transfer learning, a small-scale smoke extraction training set was made, and the smoke extraction performance was compared before and after applying transfer learning using a public cloud dataset. As a result, not only the performance in the visible light wavelength band was enhanced but also in the near infrared (NIR) and short-wave infrared (SWIR). Through the results of this study, it is expected that the lack of datasets, which is a critical limit for using deep learning on smoke extraction, can be solved, and therefore, through the advancement of smoke extraction technology, it will be possible to present an advantage in monitoring wildfires.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.205-215
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• 2021

This study was conducted to provide basic data to establish health promotion and chronic disease management education programs and educational plans for well-aging by investigating the educational needs for health promotion and chronic disease management by life cycle. This is a descriptive correlation research study, and collected and analyzed through a structured questionnaire targeting 330 adults over 19 years of age registered at Gallup Korea. The results of the study were perceived health status 3.11 points (SD=.72), health promotion behavior 2.27 points (SD=.47), and health-related quality of life 0.92 points (SD=.10). Health-related quality of life was found to have a positive correlation with perceived health status (r=.472, p<.001) and health promotion behavior (r=.122, p<.026). The priority of educational needs and contents for health promotion and chronic disease management was the highest in chronic disease management. There was a significant difference according to the life cycle (p=0.001), and it was found that the mature stage was more likely to be aware of the level of knowledge, the need for education, and the willingness to participate in education compared to the youth. Through the results of this study, it is necessary to develop a comprehensive customized program that is subdivided according to the life cycle when developing health promotion and chronic disease management education programs for well-aging.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.354-360
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• 2021

People hope to live a healthy and happy life achieving satisfaction by striking a good work-life balance. Therefore, there is a growing interest in well-aging which means living happily to a healthy old age without worry. This study identified important factors related to well-aging by analyzing news articles published in Korea. Using Python-based web crawling, 1,199 articles were collected on the news service of portal site Daum till November 2020, and 374 articles were selected which matched the subject of the study. The frequency analysis results of text mining showed keywords such as 'elderly', 'health', 'skin', 'well-aging', 'product', 'person', 'aging', 'female', 'domestic' and 'retirement' as important keywords. Besides, a social network analysis with 45 important keywords revealed strong connections in the order of 'skin-wrinkle', 'skin-aging' and 'old-health'. The result of the CONCOR analysis showed that 45 main keywords were composed of eight clusters of 'life and happiness', 'disease and death', 'nutrition and exercise', 'healing', 'health', and 'elderly services'.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.713-720
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• 2022

The objective of this study is to provide the basic data for the development of educational programs for the prevention of infectious diseases targeting the elderly by researching the degree of personal hygiene practice, perceived risk of infection, and knowledge and importance of infectious diseases for the prevention of infectious diseases of the elderly. Using the structured questionnaire for a month of October in 2021, this study surveyed total 110 elderly people in their 65 or up by using the one-to-one individual interview method through the Gallup Korea. The collected data was analyzed by using the IBM SPSS Statistics 25.0 Program. In the results of analyzing the ranking by converting it into Borich's needs formula and then totaling up the degree of importance and knowledge, it was researched as the 1^st place for the transmission path of infectious diseases, the 2^nd place for the preventive method of infectious diseases, the 3^rd place for the treatment method of infectious diseases, the 4^th place for the handling procedure in case an infectious disease was doubted and confirmed, and the 5^th place for the major symptoms of infectious diseases. The results of this study could contribute to the improvement of infection preventive practice through the provision of proper information to subjects, by providing the basic data for the development of educational programs for the elderly reflecting the needs of prevention and management of infectious diseases.

• Clinical Pain
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• v.18 no.1
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• pp.24-30
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• 2019

Objective: Greater occipital nerve block (GONB) is a widely accepted treatment of primary headaches. Two ultrasound (US)-guided blockade techniques exist: 1) the classical distal nerve block technique performed medial to the occipital artery at the superior nuchal line, and 2) the new proximal nerve block technique performed at the obliquus capitis inferior muscle at the level of C2. Our study aim was to perform a head-to-head comparative study of these two US-guided techniques. Method: Forty-nine patients with primary headache treated in our university hospital were recruited. Patients were randomized into two groups of the classical nerve block and the new proximal nerve block techniques. The headache questionnaire was made to assess the intensity of the pain of headache attacks, number of days they experience headache, duration of headache, and amount of pain medication they consumed. Results: In both groups, a decrease in the severity and frequency of the headache was observed. There was no measurable difference in outcome between the two groups. Conclusion: Our study showed that the classic and new proximal techniques are equally effective in decreasing the headache severity and frequency.

• Journal of Internet of Things and Convergence
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• v.10 no.4
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• pp.1-8
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• 2024

As technology advances, Internet of Things (IoT) technology is rapidly evolving as well. Various protocols, including Message Queuing Telemetry Transport (MQTT), are being used in IoT technology. MQTT, a lightweight messaging protocol, is considered a de-facto standard in the IoT field due to its efficiency in transmitting data even in environments with limited bandwidth and power. In this paper, we propose a method to improve the message transmission method in MQTT 5.0, specifically focusing on the shared subscription feature. The widely used round-robin method in shared subscriptions has the drawback of not considering the current state of the clients. To address this limitation, we propose a method to select the optimal transmission method by considering the current state. We model this problem based on Markov decision process (MDP) and utilize Q-Learning to select the optimal transmission method. Through simulation results, we compare our proposed method with existing methods in various environments and conduct performance analysis. We confirm that our proposed method outperforms existing methods in terms of performance and conclude by suggesting future research directions.

• The korean journal of orthodontics
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• v.40 no.6
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• pp.373-382
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• 2010

Objective: The purpose of this study was to assess the dentoalveolar compensation in facial asymmetry individuals using an integration of a CBCT image and a laser scanned dental cast image. Methods: The subjects consisted of 30 adults with asymmetric mandibles and 20 adults with symmetric mandibles. The CBCT and laser scanned dental cast images were integrated with a registration technique. Canine and first molar position and angulation were assessed from reference coordinates. The differences between deviated and non-deviated sides were analyzed with the paired t-test. The differences shown according to menton deviation were also statistically analyzed using Pearson correlation analysis. Results: The experimental group showed deviated and non-deviated side differences (dev.-ndev.) in the position and angle of the canine and first molars. Menton deviation showed positive correlation with the deviation side (dev.-ndev.) for the maxillary and mandibular 1st molar angles, negative correlation with the deviation side for the vertical position of the maxillary 1st molars, transverse position of the mandibular canine, transverse position and vertical position of the mesio-lingual cusp of the mandibular 1st molars. Conclusions: The upper and lower canine and first molars of facial asymmetry individuals were compensated, so the transverse position, vertical position, and angle showed differences between the deviated/non-deviated sides.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.169-174
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• 2017

Acute and chronic toxicities of methyl ethyl ketone and methanol were investigated on Paronychiurus kimi (Collembola), for evaluating the potential effects of accidental exposures of these chemical substances on the terrestrial environments. This study was undertaken to establish a toxicity database for these chemical substances, which was required for the preparation of the response compensation and liability act for agricultural production and environmental damage. The 7-d acute toxicity and 28-d chronic toxicity were conducted using the OECD artificial soil spiked with varying, serially diluted concentrations of methyl ethyl ketone and methanol. Mortality was recorded after 7-d and 28-d of exposures, and the number of juveniles were determined after 28-d of exposure in the chronic toxicity test. In both assessments, methanol was more toxic than methyl ethyl ketone in terms of mortality ($LC_{50}$) and reproduction ($EC_{50}$). The 7-d $LC_{50}$ of methyl ethyl ketone and methanol were 762 and $2378mg\;kg^{-1}$ soil dry wt., respectively, and the 28-d $LC_{50}s$ were 6063 and $1857mg\;kg^{-1}$ soil dry wt., respectively. The 28-d $EC_{50}$ of methyl ethyl ketone and methanol were 265 and $602mg\;kg^{-1}$ soil dry wt., respectively. Comparison of results obtained in this study with literature data revealed that P. kimi was more sensitive to methanol than other soil invertebrates. However, given the high volatility of the chemicals tested in this study, further studies are necessary to improve the current test guideline, or to develop new test guidelines for an accurate assessment of chemicals that require toxicity databases for chemical accidents.