• Clean Technology
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• v.24 no.4
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• pp.339-347
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• 2018

In order to cope with environmental problems and climate change caused by fossil fuels, renewable energy supply is increasing year by year. Currently, waste energy accounts for 60% of renewable energy production. However, waste has a lower calorific value than fossil fuels and contains various harmful substances, which causes serious problems when applied to power generation boilers. In particular, the chlorine in the waste fuel increases slagging and fouling of boiler heat exchangers, leading to a reduction in thermal efficiency and the main cause of high temperature corrosion, lowering facility operation rate and increasing operating cost. In this study, the high temperature corrosion experiments of superheater materials (ASME SA213/ASTM A213 T2, T12 and T22 alloy steel) by alkali chlorides were conducted, and their corrosion characteristics were analyzed by the weight loss method and SEM-EDS. Experiments show that the higher the temperature and chloride content, the more corrosion occurs, and KCl further corrodes the materials compared to NaCl under the same condition. In addition, the higher the chromium content of the material, the better the corrosion resistance to the alkali chlorides.

• Journal of the Korean Geotechnical Society
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• v.35 no.8
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• pp.17-30
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• 2019

Based on pile load test results for various pile types that were constructed in-situ and pile design data of prebored PHC piles, the ratio of skin friction to total capacity (SRF) was analyzed. A SRF distribution range from the pile load test results for pilot test prebored PHC piles was 42~99% regardless of relative penetration lengths, soil types, and pile load test types. However, a SRF distribution range from the pile design data for prebored PHC piles was 20~53% regardless of relative penetration lengths and pile diameters. Also, a SRF distribution range from the restrike dynamic pile load test results for pretest working prebored PHC piles was a scattered range of 4~83% regardless of pile diameters, relative penetration lengths and soil types. The scattered SRF of pretest working piles was caused to the quality control issue on the filling of cement milk around piles and this quality control issue should be improved. The average SRF calculated by the current design method was estimated to be 2.2 times lower than the average SRF of the pilot test piles. It is because skin friction resistance is calculated at a very low level. Therefore, a new design method for skin friction will be proposed based on this study.

• 재활복지
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• v.21 no.4
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• pp.177-193
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• 2017

The purpose of this study was to examine the factors that affect the awareness of disabled in undergraduate students. A sample of 1,998 respondents was surveyed. Of these, a total of 1,957 questionnaires were analysed excluding the 41 questionnaires that did not agree with the survey or had a missing data. The questionnaire consists of the general characteristics, experience related to disability and disability awareness and we used a 4-point Likert scale. Collected data was analyzed using the SPSS 24.0 program and descriptive statistics, t-test, variance analysis and multiple regression analysis were used. According to the results of the study, the disability awareness score of our respondents was average 40.52. Second, female students had more positive about disability awareness than male ones, and senior students had more positive awareness than other grade students. Third, non-rehabilitation department students' disability awareness was more positive than rehabilitation students. Fourth, the disability awareness of people who have a acquaintance member with disability or health worker were significantly positive. Finally, the awareness of people who experienced at the disability related institution were significantly positive. Therefore, to improve the awareness of undergraduate students about disabilities, it is required to activate positive contact experiences with people with disabilities rather than theoretical learning.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.49-60
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• 2019

With the appearance of self-driving cars and electric cars, the automobile industry is rapidly changing. In the midst of these changes, HMI studies are becoming more important as to how the driver obtains safety and convenience with controlling the vehicle. This study sought to understand how automobile manufacturers understand the driving situation, and how they define and limit driver interaction. For this, prior studies about HMI were reviewed and 15 participants performed an on-road study to drive vehicles from five manufacturers with using their interfaces. The results of the study confirmed that buttons and switches that are easily controlled by the user while driving were different from manufacturer to manufacturer. And there are some buttons that are more intensively controlled and others that are difficult to control while driving. It was able to derive 'selection and concentration' from Audi's vehicle, 'optimization of the driving ' from BMW's, 'simple and minimize' from Benz's vehicle, 'remove the manual distraction' from the vehicle of Lexus, and 'visual stability' from KIA's vehicle as the distinctive keywords for the HMI. This shows that each manufacturer has a different definition and interpretation of the driver's driving control area. This study has a distinct value in that it has identified the characteristics of vehicle-specific HMI in actual driving conditions, which is not apparent in appearance. It is expected that this research approach can be useful to see differences in interaction through actual driving despite changes in driving environment such as vehicle platooning and self-driving technology.

• Convergence Security Journal
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• v.18 no.1
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• pp.19-31
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• 2018

As the ICT technologies advance, the unprecedently large amount of digital data is created, transferred, stored, and utilized in every industry. With the data scale extension and the applying technologies advancement, the new services emerging from the use of large scale data make our living more convenient and useful. But the cybercrimes such as data forgery and/or change of data generation time are also increasing. For the data security against the cybercrimes, the technology for data integrity and the time verification are necessary. Today, public key based signature technology is the most commonly used. But a lot of costly system resources and the additional infra to manage the certificates and keys for using it make it impractical to use in the large-scale data environment. In this research, a new and far less system resources consuming signature technology for large scale data, based on the Hash Function and Merkle tree, is introduced. An improved method for processing the distributed hash trees is also suggested to mitigate the disruptions by server failures. The prototype system was implemented, and its performance was evaluated. The results show that the technology can be effectively used in a variety of areas like cloud computing, IoT, big data, fin-tech, etc., which produce a large-scale data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.648-655
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• 2019

This paper proposes the differential development of a Taekwondo electronic body protector. For this development, the most suitable sensor system was selected after analyzing and testing various sensor methods (magnetic sensors, electric capacity sensors, contact switch sensors, and piezo-film sensors) that could be applied in the electronic body protector, the selected sensors were distributed to the body and feet to make a more precise hit score, unlike the existing system in which all sensors are centralized on the body. Furthermore, it aims to illuminate using a lightweight film-type piezoelectric sensor on the body protector. In the case of an existing electronic body protector, all sensors and network device were concentrated on the body protector, so users need to purchase a set if they want it. On the other hand, the proposed system cloud can be used individually using a smart scoring WEP program. The effects of decreasing weight by up to 20% were compared with those of the existing system. Setting up a test facility is very difficult, so more study will be needed to analyze the effects of a hit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.417-426
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• 2019

This study examined to offer practical implications for the bullying for the prevention and response in early childhood education at the scene of the bullying that occur by to confirm the perception of the bullying to pre-service early childhood teachers. The survey questionnaire was completed by 313 pre-service early childhood teachers. SPSS Win program was used to perform frequency analysis, ANOVA. (1)The perception of bullying were significantly different according to grade and experience of child care practice, classroom observation, education program for taking preventive measure. (2)Teachers' perception about the action that can be seen as bullying followed by 'apply the violence, such as kicking, or were frequent', 'shared in things that often prevents','often to another carrier or shame in front of a friend'. (3)Perception about characteristics of bullying Perpetrators was 'aggressive behavior and talk much' and perception about characteristics of bullying victims was 'shy and not much'. (4)The reason of bullying perpetrators was 'Just for fun without a special reason' and the cause of bullying victims was 'problem of parents' child-rearing attitudes and home environment'. (5)Important institutions to combat bullying prevention followed by teacher, parents and family, community and the nation, preschool educational institution. Teachers guidance content of combat and prevent bullying was 'to be isolated from the class to infants continue to monitor'. Parents guidance content of combat and prevent bullying was 'communicate a lot and attention to children'. Early childhood education institutions guidance content of combat and prevent bullying was 'operations to come up with the bullying prevention education in educational time'. This study indicated that it is necessary to make efforts for increasing perception of bullying in pre-service early childhood teachers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.630-637
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• 2019

The scientific, economical and industrial values of the Moon have been increased, as massive ice-water and rare resource were founded from the lunar exploration missions. Korea and other major space agencies in the world are competitively developing the ISRU (In Situ Resource Utilization) technology to secure future lunar resource as well as to construct the lunar base. To prepare for the lunar construction, it is essential to develop the rover based construction spatial information technology to provide a decision-making aided information during the lunar construction process. Thus, this research presented the construction spatial information technology based upon rover's camera system. Specifically, the conceptual design of rover based camera system was designed for acquisition of a rover's navigation image, and lunar terrain and construction images around the rover. The reference architecture of the rover operation system was designed for computation of the lunar construction spatial information. Also, rover's localization and terrain reconstruction methods were introduced considering the characteristics of lunar surface environments. It is necessary to test and validate the conceptual design of the construction spatial information technology. Thus, in the future study, the developed rover and rover operation system will be applied to the lunar terrestrial analogue site for further improvements.

• Clean Technology
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• v.27 no.2
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• pp.115-123
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• 2021

This study demonstrates a new method for the synthesis of organic-inorganic hybrid particles composed of an inorganic silica shell and organic core particles. The organic core particles are prepared with a uniform size using droplet-based microfluidic technology. In the process of preparing the organic core particles, uniform droplets are generated by independently controlling the flow rates of the dispersed phase containing photocurable resins and the continuous phase. After the generation of droplets in a microfluidic device, the droplets are photo-polymerized as particles by ultraviolet irradiation at the ends of microfluidic channels. The core particle is coated with a nano complex composed of polyallylamine hydrochloride (PAH) and phosphate ion (Pi) through strong non-covalent interactions such as hydrogen bonding and electrostatic interaction under optimized pH conditions. The polyamine nano complex rapidly induces the condensation reaction of silicic acid through the arranged amine groups of the main chain of PAH. Therefore, this method enabled the preparation of organic-inorganic hybrid particles coated with inorganic silica nanoparticles on the organic core. Finally, we demonstrated the synthesis of organic-inorganic hybrid particles in a short time under ambient and environmentally friendly conditions, and this is applicable to the production of organic-inorganic hybrid particles having various sizes and shapes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.659-666
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• 2021

This study aimed to investigate the effect of changes in pressure levels and gaze directions on deep neck flexor muscle thickness. Twenty-seven subjects participated in this study. Ultrasound imaging of the longus colli (LC) and sternocleidomastoid (SCM) were measured in four gaze directions (0°, 20°, 40°, 60°) and five pressure levels (20 mmHg, 22 mmHg, 24 mmHg, 26 mmHg, 28 mmHg) during cranial-cervical flexor (CCF) exercises. Repeated ANOVA was performed for analysis of muscle thickness difference according to gaze direction and pressure levels in LC and SCM. Results: LC showed a significant difference between 0° and 20°, 0° and 40°, and 0° and 60° at pressures of 20 mmHg and 22 mmHg (p<.05). SCM displayed a significant difference between 0° and 20°, 20° and 40°, and 40° and 60° at 28 mmHg (p<.05). In this study, it was found that setting the gaze direction to 20° for the CCF exercise can increase the activation of LC and lower the activity of SCM to obtain the effect of exercise. Based on the results of this study, it is hoped that the beneficial effects of the CCF exercise can be increased by setting an optimal gaze direction in a clinical environment.