• KIPS Transactions on Software and Data Engineering
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• v.9 no.3
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• pp.109-122
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• 2020

In recent, projection mapping, which has attracted high attention in the field of realistic media, is regarded as a technology to increase the users' immersion. However, most existing methods perform projection mapping on static objects. In this paper, we developed a technology to track the movements of users and dynamically map the media contents to the users' bodies. The projected media content is built by predefined gestures just using the user's bare hands without the special devices. An interactive immersive media system has been implemented by integrating these dynamic projection mapping technologies and gesture-based drawing technologies. The proposed realistic media system recognizes the movements and open / closed states of the user 's hands, selects the functions necessary to draw a picture. The users can freely draw the picture by changing the color of the brush using the colors of any real objects. In addition, the user's drawing is dynamically projected on the user's body, allowing the user to design and wear his t-shirt in real-time.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.613-622
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• 2007

The purpose of this study was to evaluate the effect of fluoride varnish on prevention of enamel demineralization. Eighty bovine enamel blocks were divided randomly into 4 groups of 20 specimens: Group I served as the control with no topical application of fluoride. Group II was treated with APF gel for 4 minutes. Group III was treated with Fluor $Protector^{(R)}$. Group IVV was treated with $CavityShield^{TM}$. After 24 hours of treatment, samples were brushed with a soft bristled tooth brush to stimulate normal mechanical wear of varnish. Early caries lesions were produced by placing each specimen into demineralization solution at pH 4.0 for 48 hours. Then the optical density of the lesions was measured by light fluorescence induced by plasma light and the surface microhardness were measured by the vicker's hardness test. The results were as follows: 1. The optical densities of group III, IV were significantly higher than that of group II, but no significant difference was noted between group III and IV. 2. The surface microhardness of group IV was the highest, followed by group III, II, and I(p<0.05). 3. There were no significant differences between group III and IV in optical density. However, the surface microhardness of group IV was significantly higher than that of group III. The results of present study indicate that the fluoride varnish is more effective than APF gel for prevention of dental caries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.97-102
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• 2020

With the advancement of technology, there are almost no constraints on expression in virtual reality (VR) art; however, it still has some limitations. VR artists can be largely classified into two groups in terms of style. The first group is artists who create their works as a live performance. In this case, a major limitation is that the artist cannot see how the audience reacts to the work because he/she wears a VR device while performing, and the audience cannot fully experience the work, since they view it only on-screen without any VR devices. This problem can be solved if all members of the audience wear VR devices; however, that requires astronomical costs and brings about another problem related to device management. If the price of VR devices decreases as technology develops, it may help solve this problem. The second group is exhibition artists who regularly display their works online. In this case, the limitation is that their work using VR remains only in the virtual digital space. In this case, a solution may be creating space in exhibition halls, and providing VR devices to audience members in existing art exhibitions.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.51-58
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• 2021

This study proposes the design and implementation of a low-cost emergency ventilator which can be helpful during the COVID-19 pandemic where the supply of automatic ventilators is not smooth compared with the urgent demand worldwide. Easy implementation and lower price were made possible by using AMBU-bag and off-the-shelf embedded micro-controller board. Moreover, while 3D printing is used by companies and experts around the world to build prototype hardware, materials which are readily available from surrounding environments so that people in countries where it is difficult to access many advanced technologies could manufacture the system. The design features AMBU-bag automation, not use 3D printing, and it can contrl speed. By allowing speed control, ventilation can be performed according to the conditions of the patient being used. A complementary point in the study is that it is difficult to fix the start point of the wiper motor used first. A method for complementing this is a method for replacing the brush DC motor with a position feedback function. Secondly, the AMBU-bag may wear out in the long-term process of compressing the AMBU-bag because the arm and the fixing frame are made of wood. To complement this, the part of fixing frame and arm parts that the AMBU-bag touches need to be wrapped in a material such as silicon to minimize friction.