• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.256-264
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• 2010

In this paper, a digital controller of magnetic bearing system for a high vacuum turbomolecular pump (TMP) is designed and examined. For stabilizing and providing damping in magnetic bearing, the digital PID controller is applied for each 5 control axes, and the inter-axis cross feedback controller is also applied to suppress low frequency vibration caused by gyroscopic moment of the rotor at high speed of rotation. The fabricated rotor-shaft has its first flexible natural frequency lower than maximum speed, about 614Hz, so the two lead filters are applied to increase damping of flexible mode. Notch filters with rotating frequency were selected to reduce vibration of the pump housing caused by unbalance load. The implemented controllers are verified by examination of frequency response and rotating test up to 40,000 rpm, which is higher than critical speed of backward flexible mode.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.983-986
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• 2007

Concrete surface grinding is required for flatness and adhesiveness of concrete surface. The procedure is, however, labor intensive and has a hazardous work condition. Also, the productivity and the quality of concrete surface grinding depend on the levels of worker. Thus, the development of remote controlled concrete surface grinding equipment is necessary to prevent the environmental pollution and to protect the workers from hazardous work condition. However, it is difficult to evaluate the grinded surface objectively in a remote controlled system. The machine vision system developed in this study takes the images of grinded surface with the network camera for image processing. Then, by representing the quality test results to the graphic MMI program of the remote control station, the quality control system is constructed. The machine vision algorithm means the image processing algorithm of grinded concrete surface and this paper presents the objective quality control standard of grinded concrete surface through the application of the suggested algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2984-2994
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• 2013

The emergence of smart phones has brought about a revolution in introducing a computer into the palm of a hand, and this revolution has lead to a smart society that offers comfort and joy in life; however, some side effects including a smart phone syndrome have been identified on a wider and more varied scale compared with any other IT devices of the past. This paper deduced side effect types and key issues according to type focusing on risk factors in accordance with the purpose of the use of smart phones, and diagnosed social effects based on them. In addition, based on the diagnosed results, the study proposed solutions to minimize side effects in order to produce social understanding and sympathy concerning the desirable utilization of smart phones. The proposed solutions should be able to cope with visible and potential side effects systematically by helping people to utilize smart phones, which are a platform of creativity, cooperation, communications, and entertainments, in a desirable way.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.215-220
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• 2019

The block chain technology is a technique that prevents manipulation of data and ensures integrity and reliability. Ethereum is building a smart contract environment as a type of encryptionenabled system based on block chains. Smart contracts can be implemented when conditions are met, thus increasing confidence in digital data. However, smart contracts that are being tried in various ways are not covered by information security and personal information protection. The structure in which the network participant can view the open transaction ledger is exposed to data or personal information listed in the block chain. In this study, it is possible to manage the data of personal information recorded in the block chain directly. This study is protected personal information by preventing the exposure of personal information and by executing time code, it is possible to erase recorded information after a certain period of time has elapsed. Based on the proposed system in the future, it is necessary to study the additional management techniques of unknown code defects or personal information protection.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.81-88
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• 2019

This study suggests the ways to promote the technology startups founded by professor, who differs from student or researcher in social status, risk-taking tendency, and motivation. Literatures were reviewed to understand the advantage of faculty's tech start-up, foreign cases, and related researches. In addition, key stakeholders were interviewed. The study shows that domestic faculty entrepreneurship is currently in infant stage while facing obstacles in institutional, financial and practical aspects. In order to promote faculty entrepreneurship, the study suggests that university and professor set up the benefit sharing structure in advance, that the public sector establishes a holding company or investment fund dedicated to support a faculty startup, that proactive effort be made to attract passive professors to the startup world, and that private companies join faculty startups in the process of concept proofing and product commercialization. The study is expected to provide government, university, and industry with practical implication in promoting faculty startup.

• Journal of Global Scholars of Marketing Science
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• v.18 no.2
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• pp.89-111
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• 2008

Due to the development of digital technology, studies regarding smart wear integrating daily life have rapidly increased. However, consumer research about perception and attitude toward smart clothing hardly could find. The purpose of this study was to identify innovative characteristics and perceived risk of smart clothing and to analyze the influences of theses factors on product attitudes and intention to adopt. Specifically, five hypotheses were established. H1: Perceived attributes of smart clothing except for complexity would have positive relations to product attitude or purchase intention, while complexity would be opposite. H2: Product attitude would have positive relation to purchase intention. H3: Product attitude would have a mediating effect between perceived attributes and purchase intention. H4: Perceived risks of smart clothing would have negative relations to perceived attributes except for complexity, and positive relations to complexity. H5: Product attitude would have a mediating effect between perceived risks and purchase intention. A self-administered questionnaire was developed based on previous studies. After pretest, the data were collected during September, 2006, from university students in Korea who were relatively sensitive to innovative products. A total of 300 final useful questionnaire were analyzed by SPSS 13.0 program. About 60.3% were male with the mean age of 21.3 years old. About 59.3% reported that they were aware of smart clothing, but only 9 respondents purchased it. The mean of attitudes toward smart clothing and purchase intention was 2.96 (SD=.56) and 2.63 (SD=.65) respectively. Factor analysis using principal components with varimax rotation was conducted to identify perceived attribute and perceived risk dimensions. Perceived attributes of smart wear were categorized into relative advantage (including compatibility), observability (including triability), and complexity. Perceived risks were identified into physical/performance risk, social psychological risk, time loss risk, and economic risk. Regression analysis was conducted to test five hypotheses. Relative advantage and observability were significant predictors of product attitude (adj $R^2$=.223) and purchase intention (adj $R^2$=.221). Complexity showed negative influence on product attitude. Product attitude presented significant relation to purchase intention (adj $R^2$=.692) and partial mediating effect between perceived attributes and purchase intention (adj $R^2$=.698). Therefore hypothesis one to three were accepted. In order to test hypothesis four, four dimensions of perceived risk and demographic variables (age, gender, monthly household income, awareness of smart clothing, and purchase experience) were entered as independent variables in the regression models. Social psychological risk, economic risk, and gender (female) were significant to predict relative advantage (adj $R^2$=.276). When perceived observability was a dependent variable, social psychological risk, time loss risk, physical/performance risk, and age (younger) were significant in order (adj $R^2$=.144). However, physical/performance risk was positively related to observability. The more Koreans seemed to be observable of smart clothing, the more increased the probability of physical harm or performance problems received. Complexity was predicted by product awareness, social psychological risk, economic risk, and purchase experience in order (adj $R^2$=.114). Product awareness was negatively related to complexity, meaning high level of product awareness would reduce complexity of smart clothing. However, purchase experience presented positive relation with complexity. It appears that consumers can perceive high level of complexity when they are actually consuming smart clothing in real life. Risk variables were positively related with complexity. That is, in order to decrease complexity, it is also necessary to consider minimizing anxiety factors about social psychological wound or loss of money. Thus, hypothesis 4 was partially accepted. Finally, in testing hypothesis 5, social psychological risk and economic risk were significant predictors for product attitude (adj $R^2$=.122) and purchase intention (adj $R^2$=.099) respectively. When attitude variable was included with risk variables as independent variables in the regression model to predict purchase intention, only attitude variable was significant (adj $R^2$=.691). Thus attitude variable presented full mediating effect between perceived risks and purchase intention, and hypothesis 5 was accepted. Findings would provide guidelines for fashion and electronic businesses who aim to create and strengthen positive attitude toward smart clothing. Marketers need to consider not only functional feature of smart clothing, but also practical and aesthetic attributes, since appropriateness for social norm or self image would reduce uncertainty of psychological or social risk, which increase relative advantage of smart clothing. Actually social psychological risk was significantly associated to relative advantage. Economic risk is negatively associated with product attitudes as well as purchase intention, suggesting that smart-wear developers have to reflect on price ranges of potential adopters. It will be effective to utilize the findings associated with complexity when marketers in US plan communication strategy.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.507-516
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• 2013

The purpose of this study is to identify physical activity levels of the basic livelihood security recipients elderly women, to investigate relation between cardiovascular disease risk factors and sacrcopenia based on the levels, and to develop physical activity programs for healthy life of the elderly. The subjects of this study were 134 old females with $71{\pm}6.67$ years old who used senior centers in K-gu. The authors used the International Physical Activity Questionnaire for investigating the physical activity levels of the elderly, measuring their physical activity levels for seven days on average and classifying them into two groups, the Low Physical Activity (n=77) and the Moderate Physical Activity (n=57) groups based on the levels. Blood pressure, waist measurement, TC, HDL-C, LDL-C, TG, Glucose, and atherogenic index (AI) were measured as the cardiovascular disease risk factors; percent body fat, appendicular skeletal muscle mass, total muscle mass, and skeletal muscle index were measured as factors related to sarcopenia. Independent samples t-Test was conducted to analyze differences on the two groups based on the physical activity levels, with ${\alpha}=.05$ the as significance level. According to the results, HDL (p=.017) were higher and AI (p=.007) was lower; percent body fat (p=.008) was lower, and ASM (p=.000), total muscle mass (p=.000), and SMI (p=.001) were higher. In conclusion, moderate intensity physical activities rather than low intensity ones may have positive effects on the cardiovascular disease risk factors and sarcopenia levels, and participation in regular physical activities with at least moderate intensity by various methods may be needed for prevention of illness and healthy life of the elderly.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.200-201
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• 2023

Digital twin technology is used in various fields as a method of creating a virtual world to minimize the cost of solving problems in the real world, and is also actively used in the maritime field, such as large-scale systems such as ships and offshore plants. In this paper, we tried to build a digital twin of coastal waters using a ship-handling simulator. The digital twin of the coastal waters developed in this way can be used to safely manage Korea's coastal waters, where maritime traffic is complicated, by providing a actual maritime traffic data. It can be usefully used to develop and advance technologies related to maritime autonomous surface ships and intelligent maritime traffic information services in coastal waters. In addition, it can be used as a 3D-based monitoring equipment for areas where physical monitoring is difficult but real-time maritime traffic monitoring is necessary, and can provide functions to safely manage maritime traffic situations such as aerial views of ports/control areas, bridge views/blind sector views of ships in operation.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1998.12a
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• pp.201-210
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• 1998

전자상거래의 활성화를 위한 전자지불시스템은 보안성과 통용성의 양면을 만족해야한다. 현재 서비스중인 전자현금이나 전자화폐는 디지털정보가 직접 화폐가치를 지니고 있기 때문에 인터넷에서 분실시 복구가 불가능하다. 또한 전자수표나 가상은행을 이용한 계좌이체방식은 인터넷 통용성이 약하며, 신용카드를 이용한 전자지불시스템은 통용성은 양호하나 신용카드번호 노출의 위험이 있고 수수료 등 트랜잭션 비용이 소요되므로 소액지불에는 불리하다. 전자지불시스템의 활성화를 위해서는 신용카드와 같이 휴대 가능하고 실세계에서의 통용성이 우수한 시스템이어야 하며, 직접 지불이 가능하고 소액지불도 가능한 체계이어야 한다. 본 논문에서는 제안하는 새로운 지불시스템 "스마트-Pay"는 모든 사람들이 은행을 사용하고 있다는 점을 착안하여 은행계좌기반이면서 실세계 및 인터넷에서 직접지불이 가능하도록 설계한 것이다. 본 지불시스템의 안전도는 발행기관, 은행, 고객으로 이어지는 인증사슬에 의한 강력한 인증과 스마트카드에 의한 전자서명에 의존하며 기밀성, 무결성, 부인봉쇄를 제공하므로 안전하다고 평가된다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.113-115
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• 2015

각종 자연적 사회적 재난 위험의 증가와 함께 국내에서도 선진국과 같은 대국민 경보 전달체계의 정비가 진행중이다. 본 연구는 경보 전달 체계에 대한 시민들의 인식 실태를 조사 분석하고, 시민들의 인식을 바탕으로 한 시스템 개선 방향점을 찾아보고자 했다. 조사 결과에 의하면 현재 시민들의 경보 전달에 관한 인식은 매우 낮은 것으로 나타났다. 이런 경보 전달의 문제를 해결하는 시스템적 방법으로는 도심형의 야외 디지털 전달체계와 구내방송을 활용한 건물내 전달 체계 개선이 필요한 것으로 파악되었다. 또 한편으로는 경보 상황에서 사람들의 실질적 대응 행동 유발의 전략적 사회 맥락을 제공하는 연구가 필요하다는 것이 나타났다. 예를 들어 왜 사람들은 실제 경보 메시지를 받으면 방송에 주목하게 되는지, 또 그런 시민에게 어떤 식으로 대응 행동 가이드를 제공할지가 앞으로의 과제로 부각되었다.