• The Korean Journal of Food & Health Convergence
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• v.5 no.3
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• pp.7-20
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• 2019

The use of caffeine as a psychoactive stimulant in tea has been observed to have serious negative effects in humans' systems such as respiratory, nervous, cardiovascular, renal and skeletal systems. This study was carried out to assess the levels of caffeine in 10 different tea brands available in local market in Dutse, Jigawa State, Nigeria. Quantitative analysis of caffeine was performed by a simple and fast UV-Vis spectrophotometric methods using different solvents for extraction. The caffeine content in all the tea samples analyzed in this study were below the maximum allowable limits set by the USFDA. Tea have been associated with adverse health effects and the claims made by manufacturers about the benefits of tea do not highlight risks associated with excessive consumption of a combination of the ingredients contained in tea. Long term effects of tea consumption of children and young people have not been adequately studied. Therefore, it is recommended that further research be carried out on the adverse effects of energy drinks on children. Research is also needed to be done on the effects of the combination of ingredients on health and excessive consumption of those ingredients to children and adolescents. People need to be educated and given proper awareness on the health risks associated with caffeine containing beverages.

• Convergence Security Journal
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• v.22 no.2
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• pp.67-75
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• 2022

Due to the COVID-19 pandemic, many companies have introduced remote work. However, the introduction of remote work has increased attacks on companies to access sensitive information, and many companies have begun to use cloud services to respond to security threats. This study used LDA topic modeling techniques by collecting news data with the keyword 'cloud security' to analyze changes in domestic cloud security trends before and after the COVID-19 pandemic. Before the COVID-19 pandemic, interest in domestic cloud security was low, so representation or association could not be found in the extracted topics. However, it was analyzed that the introduction of cloud is necessary for high computing performance for AI, IoT, and blockchain, which are IT technologies that are currently being studied. On the other hand, looking at topics extracted after the COVID-19 pandemic, it was confirmed that interest in the cloud increased in Korea, and accordingly, interest in cloud security improved. Therefore, security measures should be established to prepare for the ever-increasing usage of cloud services.

• Journal of Environmental Science International
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• v.23 no.6
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• pp.1095-1100
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• 2014

Keratin wastes are generated in excess of million tons per year worldwide and biodegradation of keratin by microorganisms possessing keratinase activity can be used as an alternative tool to prevent environmental pollution. For practical use of keratinase, its physicochemical properties should be investigated in detail. In this study, we investigated characteristics of keratinase produced by Xanthomonas sp. P5 which is isolated from rhizospheric soil of soybean. The level of keratinase produced by the strain P5 increased with time and reached its maximum (10.6 U/ml) at 3 days. The production of soluble protein had the same tendency as the production of keratinase. Optimal temperature and pH of keratinase were $40^{\circ}C-45^{\circ}C$ and pH 9, respectively. The enzyme showed broad temperature and pH stabilities. Thermostability profile showed that the enzyme retained 94.6%-100% of the original activity after 1 h treatment at $10^{\circ}C-40^{\circ}C$. After treatment for 1 h at pH 6-10, 89.2%-100% of the activity was remained. At pH 11, 71.6% of the original activity was retained after 1 h treatment. Although the strain P5 did not degrade human hair, it degraded duck feather and chicken feather. These results indicate that keratinase from Xanthomonas sp. P5 could be not only used to upgrade the nutritional value of feather hydrolysate but also useful in situ biodegradation of feather.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.155-164
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• 2009

Digital Content Marketplace based on Interactive Media is defmed as the marketplace for content service between contents supplier and consumer through iDTV environment. This Marketplace is increasing interest to u-Life service with Digital Environment. To Interactive Media, it can contribute to enhance its effectiveness by developing various contents and service model in the initial phase of broadcasting-communication convergence. This study designed metadata using Digital Content marketplace based on Interactive Media. Specially the matadata designing include recommendation-tag for supply supplementary content. It can support self-directed action. Through basic metadata with weight value, it is designed to support supplementary content customer to want on the marketplace. Recommendation-System can be built by many method and to recommend the service content including explicit properties using collaborative filtering method can solve limitations in existing content recommendation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.233-239
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• 2015

The demand of remote control and monitoring for efficiency and applications of LED streetlight is increasing continuously because the demand of LED streetlight was increase last few years. Existing street light remote control system is wired using a power line network. The wireless connection exists, but due to its low data transmission rate, it cannot support specialized applications. It can only support simple control and monitoring. In this paper, we propose a system that uses a IEEE 802.11s wireless mesh network based on WLAN, as a backbone network for remote control and monitoring of the LED street lights along with other specialized applications. Using the wireless mesh network for remote control and monitoring the LED street lights, the same can be used to act like a public Wi-Fi access point. We have designed Wi-Fi integrated LED streetlight controller and implemented our system. We evaluated the performance of our system on a real test bed. Our proposed system is expected to perform the role of a U-city infrastructure by utilizing the wireless mesh network.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.78-88
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• 2024

Ship-radiated noise received by passive sonar that can measure underwater noise can be identified and classified ship using Detection of Envelope Modulation on Noise (DEMON) analysis. However, in a low Signal-to-Noise Ratio (SNR) environment, it is difficult to analyze and identify the target frequency line containing ship information in the DEMONgram. In this paper, we conducted a study to extract target frequency lines using semantic segmentation among deep learning techniques for more accurate target identification in a low SNR environment. The semantic segmentation models U-Net, UNet++, and DeepLabv3+ were trained and evaluated using simulated DEMONgram data generated by changing SNR and fundamental frequency, and the DEMONgram prediction performance of DeepShip, a dataset of ship-radiated noise recordings on the strait of Georgia in Canada, was compared using the trained models. As a result of evaluating the trained model with the simulated DEMONgram, it was confirmed that U-Net had the highest performance and that it was possible to extract the target frequency line of the DEMONgram made by DeepShip to some extent.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.270-276
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• 2013

We have been unwittingly exposed to magnetic field. Biological effects due to electromagnetic field exposure has been studied over the past several decades. There has been epidemiological studies and laboratory studies. In the case of laboratory studies, the effect has been observed through the cell stimulation of an artificial magnetic field. The used frequency and waveform are various in the cell experiment, but the intensity of the magnetic field is usually around 10G. Intensity of Earth's magnetic field is about 300-400mG. Although this intensity is not much higher than artificial magnetic field as 3-4% amplitude, we can't ignore the effect because every living thing on earth has already adapted for long time ago. In this study, we have designed and implemented the 3-axis magnetic field generation system in oder to remove the static magnetic field in the real-time and kept its intensity less than ${\pm}5mG({\pm}0.5uT)$ using 3-axis helmholtz coil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.507-518
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• 2018

The purpose of this research is to prepare measures to secure the competitiveness (of Korea?) in the global market by further developing the domestic smart city business, which is in a transition period. First, we examined the origin and growth process of domestic smart city (U-City) policy, Second, we analyzed the functions and policy problems that appeared in the process of building smart cities. Third, we studied advanced cases in which smart city projects overseas were promoted in a different way from domestic ones. Fourth, we examined the concept of the expanded smart city and the pattern of policy changes in Korea. Fifth, we analyzed previous studies and presented the direction to take and challenges to overcome for the future development of smart cities in Korea. This research, which looks at the trend of domestic smart city policy from the earliest point in the past to the present, and presents the future direction based on environmental changes, is significant, in that it is expected to serve as the basis for establishing policies for the development and advancement of smart cities in the future.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.351-356
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• 2018

The aim of this study is to propose guidelines for bus-stop information design that is more congested with the advent of U-Shelter, via case studies and focus group interviews. First, the literature research explored the concept of information design and correlation of information design and route map. Second, raising problems and consider improvement plans through case study in korea, overseas. Finally, current information design was evaluated and user's requests were derived through focus group interview. The current information design had problems with lack of priority, information overlaying, and hard recognition. Priority shall be selected by bus route, direction of bus, arrival time, interval, and operating time, and information overlay can be reduced into one. Also visualize the connection and direction between the lines using schematic and two-dimensional lines and shapes for recognition. Through this study, it will be used as a reference material to help improve and develop the bus-stop information design.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.59-65
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• 2012

The evolution of cloud computing service over the recent years is potentially one of the major advances in information and communication technology. However, if cloud computing service is to achieve its potential, there needs to be a clear understanding of the various issues such as service security, performance and availability and so on, both from the perspectives of the providers and the consumers of the cloud service. As more and more information on individuals, companies and public sectors are placed in the cloud service, concerns are beginning to grow about just how safe and reliable an environment it is. In order to overcome these situations, the Korea cloud service certification system and U.S. FedRAMP were performed in each country. This paper aims at comparing and analyzing between Korean cloud service certification systems and U.S. FedRAMP and describing the difference between them. Eventually, we propose the improvement strategy of Korea cloud service certification systems based on the comparison results between them.