• 자원리싸이클링
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• 제11권2호
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• pp.28-35
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• 2002

충격형 분채기에 의한 폐프린트배선기판(PCBs)의 분쇄과정에서 일어나는 금속성분의 분쇄특성에 대한 연구가 수행되었다. PCBs로부터 금속성분들을 단체분리하기 위하여 -3 mm로 파쇄한 다음 충격형 분쇄기를 사용하여 분쇄하였으며 햄머의 회전속도가 금속성분의 분쇄에 미치는 영향을 관찰하였다. 동과 땜납 등과 같은 금속성분들의 입도분포 및 단체분리도를 조사하였다. 경사진동판을 사용하는 PCBs 분쇄물로부터 금속입자들의 형상분리에서 햄머의 회전속도와 입자크기가 미치는 영향을 검토하였다 61.3 m/s 햄머속도에서 동 성분은 +297$\mu$m 입자가 80% 이었지만 땜납성분은 -297$\mu$m 입자가 90%에 달했다. 형상분리법에 의한 금속입자의분리 시 햄머의 회전속도가 클수록 회수위치가 짧았으며 +297 $\mu$m 입자의 회수위치가 -297~+149$\mu$m 입자보다 짧았다. 회수위치가 짧을수록 금속입자의 구형도가 좋았으며 KI 값은 KI=1 로 증가하고, $\phi_{c}$ 값은 $\phi_{c}$ =1로 감소하였다.

• 대한조선학회논문집
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• 제41권6호
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• pp.75-83
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• 2004

Ice rubble pieces broken by the bow impact load and side hull of an icebreaking vessel usually pass along the ship's bottom hull and may hit the propeller/rudder or other stern structures causing serious damage to ship's hull . Therefore it is important to estimate the size of broken ice pieces during the icebreaking process. The dynamic interaction process of icebreaker with infinite ice sheet is simplified as a wedge type beam of finite length supported by elastic foundation. The wedge type ice beam is leaded with vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum dynamic bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a failure length of broken ice sheet given design parameters. The results are compared to Nevel(1961)'s analytical solution for static load and observed pattern of ice sheet failure onboard an icebreaker. Also by comparing computed failure length with the characteristic length, the meaning of ice rubble sizes is discussed.

• 가족자원경영과 정책
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• 제18권2호
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• pp.1-15
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• 2014

The purpose of this study was to investigate the impact of lifestyle on the perceived value of children in university students. Questionnaires were distributed to 467 university students with questions covering topics including general personal information and characteristics, lifestyle type, and value of children. First, a cluster analysis based on lifestyle showed that the subjects could be categorized into three groups: negative-leisure types, active-achievement types, and affirmative-fidelity types. The negative-leisure type was highly leisure-oriented and showed a negative self-value; the active-achievement type showed a perspective that valued personal and occupational self-development and a high level of labor-oriented value; and the affirmative-fidelity type favored materialism, seeking occupational aptitude and worth and showing a positive self-value. Second, an investigation of the impact of these three lifestyle types on the students' value of children revealed that the active-achievement type group had high level of belief in the necessity of childbirth, the affirmative-fidelity type group highly valued fulfilling an active parent role, and the active-achievement type group were inclined to delay childbirth. Further, the negative-leisure type group wanted the lowest number of children, while the affirmative-fidelity type group wanted the highest number of children. This study reveals that university students' lifestyle does have an effect on their value of children. It is therefore proposed that a value-focused population education for increasing fertility should relate not only to individuals' value of children but also to their broader lifestyle.

• Smart Structures and Systems
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• 제24권1호
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• pp.83-94
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• 2019

Passive negative stiffness dampers (NSDs) that possess superior energy dissipation abilities, have been proved to be more efficient than commonly adopted passive viscous dampers in controlling stay cable vibrations. Recently, inertial mass dampers (IMDs) have attracted extensive attentions since their properties are similar to NSDs. It has been theoretically predicted that superior supplemental damping can be generated for a taut cable with an IMD. This paper aims to theoretically investigate the impact of the cable sag on the efficiency of an IMD in controlling stay cable vibrations, and experimentally validate superior vibration mitigation performance of the IMD. Both the numerical and asymptotic solutions were obtained for an inclined sag cable with an IMD installed close to the cable end. Based on the asymptotic solution, the cable attainable maximum modal damping ratio and the corresponding optimal damping coefficient of the IMD were derived for a given inertial mass. An electromagnetic IMD (EIMD) with adjustable inertial mass was developed to investigate the effects of inertial mass and cable sag on the vibration mitigation performance of two model cables with different sags through series of first modal free vibration tests. The results show that the sag generally reduces the attainable first modal damping ratio of the cable with a passive viscous damper, while tends to increase the cable maximum attainable modal damping ratio provided by the IMD. The cable sag also decreases the optimum damping coefficient of the IMD when the inertial mass is less than its optimal value. The theoretically predicted first modal damping ratio of the cable with an IMD, taking into account the sag generally, agrees well with that identified from experimental results, while it will be significantly overestimated with a taut-cable model, especially for the cable with large sag.

• 한국건설관리학회논문집
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• 제4권4호
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• pp.201-211
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• 2003

불확정 요소가 많은 건설 프로젝트에서 코스트 리스크의 분석은 관련 전문가의 통찰력이나 주관적 판단에 의존하는 경우가 많다. 하지만 국내 건설산업의 경우 코스트 리스크 분석시 객관적인 산출근거에 의한 확률만을 고려 할 뿐 계량적 측정이 어려운 주관적 요소를 합리 적으로 반영하기 위한 방법이나 절차를 갖고 있지 못하다. 이와 같은 관점에서 본 연구는 보다 신뢰성이 우수한 비용견적을 위해서 전문가의 주관적인 요소까지 종합적으로 평가하고, 리스크로 인한 비용의 변동을 정량적으로 분석할 수 있는 새로운 로스트 리스크 분석모델을 제시하였다 아울러 실무에서도 간단한 절차에 따라 모델을 체계적으로 수행할 수 있도록 편리한 사용자 인터페이스를 제공해 주는 프로토타입을 구현하였다.

• 한국의류학회지
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• 제32권5호
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• pp.777-787
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• 2008

The purpose of this study is to identify impacts of adolescent consumers' assertiveness and appearance concerns on their buying behaviors when they buy school uniforms. This research examined information sources and purchase evaluative criteria as related variables of clothing buying behaviors. The Internet survey was carried out to middle and high school students in Seoul. A total of 907 data were analyzed by factor analysis, frequency analysis and step-wise multiple regression analysis. The results of this study were as follows: From a result of factor analysis on adolescent consumers' assertiveness, appearance concerns and information sources and purchase evaluative criteria for buying school uniforms, each four variances showed factorial structures clearly. School uniform consumers' assertiveness and appearance concerns had significant influences on information sources and purchase evaluative criteria. Especially, an impact of conformity appearance concern was inclined to be high on information sources and purchase evaluative criteria.

• 한국정보시스템학회지:정보시스템연구
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• 제18권4호
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• pp.87-103
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• 2009

Although the Internet has been a important communication tool in modem societies, researchers did not pay attention to its' positive impacts on individual's psychological process. The Internet provides users with a unique environment such as visual isolation, non face-to-face communication, and easiness to escape from social influences. This environment enables people to take free action according to their personality and disclose themselves. From the uses and gratification perspective, the current research reveals that individuals with high extraversion are inclined to maintain social networking sites and those with high openness participate in web communities. The findings indicate that individuals' social use of the internet may reflect their personality. This study, also, reveals that controlling the big five personality dimensions, the amount of self-disclosure through ones' social networking site is positively related with subjective happiness. This finding suggests that like confession behaviors in religious or curing facilities, people can use the Internet as a therapeutic or a preventative method for promoting their well-being. Theoretical contributions and practical implications are discussed.

• 대한안전경영과학회지
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• 제16권2호
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• pp.19-29
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• 2014

Korean societal concern for the train accidents is fast and widely increasing with an ever-increasing demand and use for KTX. Most of these train accidents are inclined to be caused by human error. Experts used to attribute the causes of human error to the defects in various aspects such as technology, organizational system, practices, corporate culture, and/or human resource itself. Among the diverse causes of human error, an important one, even though it was rarely focused, may be the issue of impact of rule or procedure change on human error. Giving attention to the implicit importance of this issue, this study intends to highlight the theme of frequent procedure change in railway driving manual as a critical factor of human error. To attain this purpose mentioned above, dual methodologies were adopted. One is to qualitatively analyze the real cases of procedure change in relevant manuals followed by the incident case(passing the station scheduled to stop) happened lately. Another is to quantitatively perform statistical analysis based on questionnaires received from 224 train drivers. Results show that frequent changes in internal affairs procedure is or may be an important factor causing stress and human error from train drivers.

• The Journal of Asian Finance, Economics and Business
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• 제8권10호
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• pp.197-205
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• 2021

This study aims to investigate factors influencing customer behavior towards nylon bags and single-use plastics. These factors are environmental protection awareness, health protection awareness, sense of responsibility, expectations, and green marketing. A quantitative method with the use of surveys is deployed to collect data of young people under 30, generating 1650 valid responses. The collected data is then analyzed with SPSS 22, using Cronbach's Alpha and Exploratory Factor Analysis to test the reliability of the model before validating the hypotheses by regression analysis. The study found that the majority of respondents are inclined to use plastic bags, despite their environmental awareness. The results also demonstrate that health consciousness, environmental concerns, self-driven responsibility for the sustainability of young people have a significant impact on their behaviors in using nylon bags and plastic products, whereas expectation and green marketing are confirmed not to be the factors. The study suggests that if green marketing is to gain higher influence, an increase in research and development to support other environmentally friendly packaging would be the right path. Finally, this research proposes some feasible recommendations for the government, which include imposing bolder and more targeted environmental policies on consumers and introducing educational campaigns to raise awareness about minimizing plastic consumption.

• 한국농공학회논문집
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• 제61권5호
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• pp.11-22
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• 2019

The purpose of this study was to examine the relationships between the community business, performance and the life satisfaction of local residents and to investigate the mediating effects that community business performance has on the life satisfaction of local residents. The results of the study investigating the effect of community business, performance and the residents' life satisfaction mediating effect of performance are summarized as follows: First, there were differences with the economical, environmental, and performance factors pertaining to the participants' age while there were no differences concerning the social-cultural factors and the life satisfaction of local residents. Second, the higher the impact a community business has, the higher the life satisfaction of the local residents have. In addition, the higher the performance in community business, the more ready local residents are to be inclined to be satisfied. Third, economical and environmental factors have direct effects on the life satisfaction of local residents, but also indirectly effect the performance of local residents. In addition, the level of performance that a community business plays has a mediating role in the life satisfaction of local residents.