• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.1
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• pp.13-21
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• 2023

As problems such as difficulties in securing stable energy resources and global warming due to the emission of greenhouse gases due to the use of fossil fuels have emerged, interest in the development of renewable energy is increasing. Since the tidal phenomenon has a regularity that occurs regularly with a certain period, it is possible to predict accurately in advance, which has a advantage in terms of energy recovery. Therefore, various methods have been devised to utilize the tide as an energy source. Tidal power using barrages is a representative method that is widely operated, but the promotion of tidal power generation projects is being delayed or stopped due to the decrease in the level of water in the tidal basin, changes in water quality and in the ecosystem. In this study, a field experiment was conducted to develop and verify the performance of a tidal power device applicable to sea areas where dykes are already installed. As a result of carrying out four cases of experiments using two water tanks, pipe lines, open channels, weirs, and water turbine and generator, the possibility of developing a power generation system capable of 10 kW output or more and 60% efficiency or more was confirmed. These research results can be used for small-scale tidal power by utilizing the existing dykes.

• Clean Technology
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• v.29 no.1
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• pp.22-30
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• 2023

Mongolia is experiencing some of the world's most serious air pollution problems. The air pollution is especially severe during the winter when raw coal and low-grade fuels are used to heat homes in Ger villages. The impact of this pollution has created significant health and socioeconomic challenges for the country. In order to mitigate this air pollution, this study analyzed the fuel quality of the low-grade fuels and Mongolian waste cooking oils used in Ulaanbaatar, Mongolia. Then the environmental characteristics of traditional stove combustion and a prototype combustion heating device were compared and analyzed. In addition, the effect of replacing the heating devices was evaluated by analyzing their risks to humans. Analysis of the fuel characteristics showed that briquettes had relatively low environmental properties as a result of their high ash, N and S content. Also, after analyzing the combustion characteristics, it was found that the air quality improvement effect was higher when waste cooking oil was burned compared to the three types of coal that were analyzed. Finally, this study evaluated the impact of replacing the Mongolia traditional stove with a prototype stove that uses waste cooking oil. The results of this study are expected to help to mitigate the air quality problems currently observed in Ulaanbaatar, Mongolia.

• Journal of IKEEE
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• v.27 no.1
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• pp.45-52
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• 2023

Cold-junction correction(CJC) and disconnection detection circuit design of various thermocouples(TC) and multi-channel TC interface circuit using them were designed. The CJC and disconnection detection circuit consists of a CJC semiconductor device, an instrumentation amplifier(IA), two resistors and a diode for disconnection detection. Based on the basic circuit, a multi-channel interface circuit was also implemented. The CJC was implemented using compensation semiconductor and IA, and disconnection detection was detected by using two resistor and a diode so that IA input voltage became -0.42V. As a result of the experiment using R-type TC, the error of the designed circuit was reduced from 0.14mV to 3㎶ after CJC in the temperature range of 0℃ to 1400℃. In addition, it was confirmed that the output voltage of IA was saturated from 88mV to -14.2V when TC was disconnected from normal. The output voltage of the designed circuit was 0V to 10V in the temperature range of 0℃ to 1400℃. The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel. The implemented multi-channel interface has a feature that can be applied equally to E, J, K, T, R, and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.33-42
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• 2007

The assessment of shear wave velocity($V_s$) in soft soils is extremely difficult due to the soil disturbances during sampling and field access. After a ring type field $V_s$ probe(FVP) has been developed, it has been applied at the southern coastal area of the Korean peninsular. This study presents the upgraded FVP "blade type FVP", which minimizes soil disturbance during penetration. Design concerns of the blade type FVP include the tip shape, soil disturbance, transducers, protection of the cables, and the electromagnetic coupling between transducers and cables. The cross-talking between cables is removed by grouping and extra grounding of the cables. The shear wave velocity of the FVP is simply calculated by using the travel distance and the first arrival time. The large calibration chamber tests are carried out to investigate the disturbance effect due to the penetration of FVP blade and the validity of the shear waves measured by the FVP. The blade type FVP is tested in soils up to 30m in depth. The shear wave velocity is measured every 10cm. This study suggests that the upgraded blade type FVP may be an effective device for measuring the shear wave velocity with minimized soil disturbance in the field.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.51-57
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• 2023

Smart mirror is an IoT device that attaches a display and an embedded computer to the mirror and provides various information to the user along with the mirror function. This paper presents performance evaluation of the CoMirror system as an extension of the previous research in which proposed and implemented the CoMirror system that connects Smart Mirrors using a network. First, the login performance utilizing face recognition was evaluated. As result of the performance evaluation, it was concluded that the 40 face images are most suitable for face learning and only one face image is most suitable for face recognition for login. Second, as a result of evaluating the message transmission time, the average time was 0.5 seconds for text, 0.63 seconds for audio, and 2.9 seconds for images. Third, as a result of measuring a video communication performance, the average setup time for video communication was 1.8 seconds and the average video reception time was 1.9 seconds. Finally, according to the performance evaluation results, we conclude that the CoMirror system has high practicality.

• Journal of Intelligence and Information Systems
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• v.28 no.1
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• pp.217-242
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• 2022

With the launch of Artificial Intelligence(AI)-based intelligent products on the market, innovative changes are taking place not only in business but also in consumers' daily lives. Intelligent products have the potential to realize technology differentiation and increase market competitiveness through advanced functions of artificial intelligence. However, there is no new product development methodology that can sufficiently reflect the characteristics of artificial intelligence for the purpose of developing intelligent products with high market acceptance. This study proposes a KANO-QFD integrated model as a methodology for intelligent product development. As a specific example of the empirical analysis, the types of consumer requirements for hair loss prediction and treatment device were classified, and the relative importance and priority of engineering characteristics were derived to suggest the direction of intelligent medical product development. As a result of a survey of 130 consumers, accurate prediction of future hair loss progress, future hair loss and improved future after treatment realized and viewed on a smartphone, sophisticated design, and treatment using laser and LED combined light energy were realized as attractive quality factors among the KANO categories. As a result of the analysis based on House of Quality of QFD, learning data for hair loss diagnosis and prediction, micro camera resolution for scalp scan, hair loss type classification model, customized personal account management, and hair loss progress diagnosis model were derived. This study is significant in that it presented directions for the development of artificial intelligence-based intelligent medical product that were not previously preceded.

• Korea Trade Review
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• v.41 no.5
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• pp.113-138
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• 2016

This study analyzed the impact when Korea expands Chinese Renminbi(RMB) as invoicing currency on the trade to China using Monte-Carlo simulation. Primarily, we analyzed the impact on the balance of Korean Won(KRW) converted from RMB in a case that simulated exchange rate(Korean won to Chinese Renminbi) and realized historically identical probability distribution but in different stochastic process. In addition, we developed the simulation of the case where the volatility of RMB to KRW exchange rate abnormally expanded. The major results found in this study are as follows. First, in the case where RMB exchange rate simulated in identical probability distribution but in the different stochastic process, no matter how much RMB was utilized as invoicing currency, expansion of the RMB exchange rate and exchange rate volatility operated as positive mechanism to increase the KRW converted balance. Secondly, while the expansion of US dollar exchange rate volatility positively influences the balance on average, it caused a polarization of balance, which makes under-average-balance lower and over-average-balance higher. On the contrary, the expansion of RMB exchange rate volatility even shows a similar mechanism but the impact is more moderate than USD exchange rate volatility. Thirdly, as RMB exchange rate volatility expanded, the balance of translated invoicing currency (RMB) declined, whilst the negative impact of RMB exchange rate volatility on balance of translated invoicing currency(RMB) showed diminishing effect. Lastly, the influence of RMB's exchange rate volatility through RMB usage ratio trends similar to bull spread strategy, which is a combination of call option with put option. Therefore, since RMB usage in invoicing currency could spawn a hedging effect, corporations might utilize RMB as a strategic device for maximizing profits.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.9
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• pp.429-442
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• 2017

This study was performed to investigate and analyze users' needs for m-health based prevention and intervention programs that are intended to improve the awareness of metabolic syndrome and promote health behaviors of college students. A questionnaire survey was conducted to 200 college students of 2 university in D city. Data were analyzed using descriptive statistics, t-tests, chi-square test with the SPSS Version 20.0. The result showed that users wanted customization of prescriptions and accurate measurement of health applications, and provided a positive feedback on information exchange between those who manage their health. The most preferred content was proper exercise methods, and the preferred gamification factors were goal-setting, compensation, and competition. The optimal price for wearable devices was between 10,000 to 50,000 won, and calorie consumption function was also preferred. Although users with experiences of wearable devices and health apps had a higher knowledge score pertaining to metabolic syndrome, there was no significant difference in the overall score. Concerning the health behaviors associated with lifestyles, individuals without the experiences of wearable devices and health apps showed a remarkably lower score. The research has a significance that it investigated and analyzed the contents needed for the development of effective moblie health based prevention and intervention programs targeting the population in their early adulthood. Therefore, based on the findings, we propose a rich and concrete follow-up study on the needs and characteristics of different user types by collecting a population with experiences of wearable devices, and a development of differentiated mobile health based prevention and intervention programs.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.119-128
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• 2022

This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30˚, from 30˚ to 180˚, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5˚. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.

• Journal of Korean Society of Rural Planning
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• v.29 no.1
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• pp.69-79
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• 2023

Uiseong-gun, Gyeongsangbuk-do, one of the representative small rain regions, has developed a traditional irrigation farming system while overcoming and adapting to unfavorable agricultural environments from the days of the ancient nation of Jomunguk to the present. In 2018, its value was recognized and designated as Nationally Important Agricultural Heritage System No. 10. This study was conducted with the purpose of examining the characteristics of the traditional irrigation farming system in Uiseong from the viewpoints of irrigation facilities, irrigation communities, and agricultural activities. The research results are as follows. Uiseong-gun has been expanding irrigation facilities for agriculture since long ago, and it has been investigated that a total of 6,227 irrigation facilities are currently distributed along the Wicheon water system that crosses Uiseong-gun from east to west. Irrigation facilities appear differently depending on the topography. The irrigation facility has a 'su-tong' as an irrigation passage and a corkscrew structure 'mot-tchong' as a water quantity control device, so the amount of water was adjusted as needed. Through this facility, surface water with warmer temperature is supplied to the farmland to prevent cold damage to crops. Uiseong has developed activities to organize irrigation communities in one village or several villages to secure agricultural water from an early age. Currently, this tradition continues, and a total of 213 irrigation communities manage 375 irrigation facilities (6.0% of all irrigation facilities). Through this organization, called Mong-ri-gye, water for agriculture is obtained, managed, and distributed equitably. In order to increase agricultural production, Uiseong implemented double cropping by converting rice fields and fields. In the case of Mt. Geumseong, double cropping of rice and barley was mainly carried out until the 1970s, but since the 1980s, double cropping of rice and garlic has been implemented with higher income. One of the unique features of the agricultural system of this region is the spectacular landscape that changes simultaneously from field to rice field in spring and from rice field to field in autumn.