• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.39-46
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• 2017

In this paper, a model updating procedure based on the response surface method combined with the multi-objective optimization was proposed and applied for updating of the FE models representing a low-rise reinforced concrete building before and after the seismic retrofit. The dynamic properties to be matched were obtained from vibration tests using a small shaker system. By varying the structural parameters according to the central composite design, analysis results from the initial FE model using a commercial software were collected and used to produce two regression functions each of which representing the errors in the natural frequencies and mode shapes. The two functions were used as the objective functions for multi-objective optimization. Final solution was determined by examining the Pareto solutions with one iteration. The parameters representing the stiffnesses of existing concrete, masonry, connection stiffness in expansion joint, new concrete, retrofitted members with steel section jacketing were selected and identified.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.55-65
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• 2015

Contrast enhancement methods for a single image applied to videos may cause flickering artifacts because these methods do not consider continuity of videos. On the other hands, methods considering the continuity of videos can reduce flickering artifacts but it may cause unnecessary fade-in/out artifacts when the intensity of videos changes abruptly. In this paper, we propose a robust method of video contrast enhancement for sudden illumination changes. The proposed method enhances each frame by Fast Gray-Level Grouping(FGLG) and considers the continuity of videos by an exponential smoothing filter. The proposed method calculates the smoothing factor of an exponential smoothing filter using a sigmoid function and applies to each frame to reduce unnecessary fade-in/out effects. In the experiment, 6 measurements are used for the performance analysis of the proposed method and traditional methods. Through the experiment. it has been shown that the proposed method demonstrates the best quantitative performance of MSSIM and Flickering score and show the adaptive enhancement under sudden illumination change through the visual quality comparison.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1798-1805
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• 2020

This study attempted to numerically verify specific effects on skin condition improvement by measuring and comparing changes in skin conditions such as pores, wrinkles, and sebum of LED masks for beauty devices with low output among light sources. 18 healthy women (4 weeks in the control group and 4 weeks in the experimental group) were conducted once a week for 8 weeks. As a result of measuring the skin condition of pores, wrinkles, and sebum, it was confirmed that the skin condition improved significantly as the LED irradiation progressed, and the difference between the groups by measurement period of the experimental group and the control group also showed significant differences in pores, wrinkles, and sebum (p< .001, p<.05). This is meaningful in that it can be presented as clinical information and quantitative data by preparing continuous data in an academic sense by proving the effect of improving the LED mask as a beauty device. It is also suggested that in the future, follow-up studies to prove more effective skin improvement will be conducted.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.90-94
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• 2011

In this paper, the energy transfer is associated with high frequency band and try to analysis the rectifier circuit structure and characteristics and find ways to maximum efficiency. Input signal at 13.56MHz is converted output DC signal with the experiments and measurements. Rectifier cirsuits can be divided into the half-wave, full-wave, bridge rectifier circuit. Research to the present with the passive components are carried out with a focus on efficiency improvements. Factors affecting the efficiency of rectification is dependent on the characteristics of the device. In this experiment, about 70% efficiency can be measured. By using an improved device for high efficiency could be obtained higher efficiency.

• Journal of the Korean Society for information Management
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• v.24 no.4
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• pp.191-221
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• 2007

The goal of this study was to examine the relationships between usability and the searching experience, and to uncover where an integrated cataloging and metadata system lay the usability problems of its primary users, catalogers. This study showed that the most important aspect of usability in Connexion lay in the experience of information retrieval system. Also, it showed there are seventeen usability problems to be improved in Connexion. Needless to say, it is most important to note that usability is not an exclusive goal of such an integrated cataloging and metadata system. Other goals such as quality of catalogs, and the reliability of its cataloging and metadata system are equally its concern. This study also suggested more testing on diverse cataloging systems and specific user groups, especially catalogers.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.125-128
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• 2008

In the recent construction industry, external tendon method has been widely used for strengthening and repair of civil structures. This paper presents the strengthening effectiveness and application of the proposed external tendons using lifting hole anchorage system. Based on the experimental results of the previous external tendons using lifting hole anchorage systems, two types of modified systems were proposed. In order to verify the strengthening effectiveness of the two systems, six beams were built and a series of experiments was carried out. To compare and analyze the behaviors of the proposed systems, deflections and strains were measured. Additionally, yield load, ultimate load and failure modes were compared and analyzed.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.221-226
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• 2008

최근 건강에 대한 사회 전반의 관심이 증대되면서 자신의 건강을 체크하고 행동 및 습관을 변화시키기 위해 휴대용 건강 체크 기기를 사용하는 사람들이 늘고 있다. 휴대용 기기 중에서 모바일은 네트워크를 사용하여 시간과 장소에 상관없이 정보 제공이 가능하기 때문에 설득적 매체로 각광받고 있다. 모바일을 통해 사용자의 태도 및 행동을 변화시키는 서비스를 제공하기 위해서는 효과적인 설득의 전략을 세워야 한다. 신뢰성(credibility)은 사람이 어떠한 대상에 대해서 믿을 수 있다고 인지한 정도를 의미하는 것으로 일반적인 설득 커뮤니케이션에서 사용자의 태도 및 행동을 변화시키는 것에 큰 영향을 주는 것으로 알려져 있다. 본 연구에서는 모바일의 매체적 설득 효과별 알아보고, 신뢰성에 영향을 주는 요인을 전문성과 믿음성으로 나누어 이들 요인에 따라서 사용자의 태도 및 행동 변화가 어떻게 달라지는지 실험을 통해 분석하였다. 실험 결과 웹을 통해 실험에 참여한 사람보다 모바일을 통해서 실험에 참가한 사람들의 식생활 개선이 크게 나타났다. 이를 통하여 웹보다 모바일의 매체적 설득 효과가 크다는 사실을 앞 수 있었다. 또한 전문가의 메시지를 받은 그룹 참가자들 중에서 설득 메시지에 대하여 인지된 신뢰성을 높게 평가한 사람의 개선 정도가 크게 나타났다. 인지된 신뢰성은 서비스 만족도에 영향을 준다는 사실도 알 수 있었는데, 이는 모바일 환경에서 신뢰성 제공 전략은 설득력을 높이기 위한 전략이면서도 사용자의 서비스 만족도를 높이기 위한 전략이 된다는 것을 의미한다. 본 연구 결과는 모바일을 통해서 사용자에게 동기를 부여하고 더 나아가 직접적인 행동 수정이 이루어지도록 하는데 이용될 수 있을 것이다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.77-86
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• 2007

The repair technique utilizing surface impregnant is widely used due to its simple construction procedures and economical benefit. Surface protection through this reparing technique cannot increase the bearing capacity of concrete members much but increase the durability performance and service life efficiently. In this study, fundamental tests such as water suction and permeation are performed for concrete specimens with several organic/inorgarnic impregnant and suitable impregnant is selected on the basis of the results. Finally, durability tests such as carbonation, freezing and thawing, and chloride attack are carried out for the concrete specimens with selected impregnant and it is experimentally verified that they have good resistance to deteriorations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.225-232
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• 2008

The object of this paper is to study the flexural strengthening effectiveness on the construction method of bonding of the FRP. The existing FRP flexural strengthening methods were divided into FRP sheet strengthening and FRP plate strengthening according to the FRP condition. For improving the existing construction method, this paper proposed the velcro type anchorage system for temporary bonding material, and flexural strengthening effects were tested. Test variables were bonding methods of the FRP strengthening materials, and total 4 specimens were tested. Following to the test results, it is shown that FRP-plate strengthening method using the velcro can get better workability than existing construction methods, and have excellent strengthening performance including flexural strength, stiffness, ductility and failure aspect.

• Journal of The Korean Association For Science Education
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• v.23 no.5
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• pp.592-598
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• 2003

The purpose of this study is to analyze the tenth grade science textbooks as an origin of misconception on greenhouse effect concept and find incorrect descriptions on that concept and then suggest some improved schemes. Some incorrect descriptions, pictures. tables and experiments related to misconceptions on greenhouse effect were found in textbooks. They are considered to contribute to form and reinforce misconceptions on that concept : the most important gas of greenhouse effect, the role of $CO_2$ on the change of greenhouse effect. global warming. energy sources, greenhouse experiments and the physical processes of greenhouse effect. So some improved schemes were suggested