• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2015년도 추계학술발표대회
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• pp.1459-1460
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• 2015

안경을 제작하기 위하여 안경테 혹은 렌즈의 사이즈를 측정하는 기계를 취형기라 하며, 측정된 데이터를 사용하여 렌즈를 절삭하는 기계를 옥습기라 한다. 본 논문에서는 취형기를 통해 획득한 데이터를 3D 시각화 하는 방법에 대하여 서술한다. 취형기의 탐침자에서 획득된 데이터는 1024개, 즉 데이터당 약 $0.352^{\circ}$에 해당하는 각도로 획득한 데이터로 구성되며, 각 데이터는 취형기 중심에서 경계까지의 거리와 렌즈 혹은 안경테의 높이 데이터를 포함한다. 해당 데이터는 취형기에서 얻은 원통좌표계 형식의 원시 데이터 형태에서 OpenGL에서 사용하기 좋은 3차원 데이터 형식으로 나타낼 수 있도록 재가공하여 X, Y, Z 축 기반의 3차원 직교좌표계 형식으로 변환한다. 그 후, OpenGL을 사용하여 3D로 시각화하였다. 해당 데이터를 회전할 수 있도록 하기 위하여 쿼터니언 기반의 ArcBall을 사용하여 회전 가능하게 하였으며, 3D 시각화 된 결과를 확대/축소할 수 있게 하였다. 디스플레이에서 실제와 같은 크기로 출력하기 위하여 DPI를 활용한 축척 계산법을 사용하였고, 출력결과의 더 나은 시각화를 위하여 평균보간법을 사용하였다.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1011-1017
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• 2023

In this study, the harmless crack size (a_hml) by double shot peening (DSP) using shot balls with different diameters was evaluated on carburized, quenched-tempered SCM822H steel. The minimum crack size (a_NDI) detectable by non-destructive inspection was also evaluated. The relationship between the crack size (a_25,50) that reduces the fatigue limit by 25% and 50% and a_hml was evaluated. The residual stress of DSP was greater in SP_(0.6+0.08) than SP_(0.8+0.08) and appeared deeper in the depth direction. In addition, the hardness below the surface appeared larger. The fatigue limit of DSP increased 2.07 times and 1.95 times compared to non-SP. All a_hml of the DSP specimen was determined at the depth (a). The compressive residual stress distribution affects a_hml, and the a_hml of SP_(0.6+0.08), which has a large compressive residual stress and a high fatigue limit, appeared large. a_hml of SP_(0.6+0.08) introduced deeper than the residual stress of SP_(0.8+0.08) is larger in the range of As=1.0-0.3. Since the residual stress in the thickness direction has a greater effect on a_hml than the residual stress at the surface, it is necessary to introduce it more deeply. The relation of a_hml, a_25,50, and a_NDI were evaluated in the point for safety and reliability.

• 자원리싸이클링
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• 제28권3호
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• pp.26-34
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• 2019

희토류 영구자석(Rare earth magnet)은 사용량이 급격하게 증가하고 있으며, 이와 맞물려 폐희토류 자석의 발생량도 급격히 증가할 것으로 예측된다. 폐희토류 자석의 재활용은 주로 자석에 포함되어 있는 희토류 원소를 침출/분리하여 회수하는 공정으로 이루어지고 있으나, 침출 공정에 투입되는 폐희토류 자석의 분쇄 특성에 대한 연구는 전무한 실정이다. 따라서 본 연구에서는 폐희토류 자석을 이용하여 효과적인 파분쇄 공정 및 분쇄특성에 대한 연구를 진행하였다. NdFeB 폐자석을 조크러셔로 파쇄한 결과 급격한 산화 없이 효과적으로 입도가 감소는 하였지만, 롤크러셔의 경우 지속적인 압축에 의해 증가하는 표면과 대기 중의 산소가 반응하여 불꽃을 내며 급격한 산화가 발생하였다. 또한 파쇄 공정을 통해 생산된 시료를 볼밀에 투입하여 분쇄 특성을 파악한 결과, 일반적인 광물과 다르게 분쇄가 잘 이루어지지 않고 분쇄 16분 이후에 정상적인 분쇄가 이루어졌다. 또한 일반적인 광물에 비해 매우 낮은 분쇄율(S)과 미분이 발생이 매우 높은 분쇄분포(B)를 보임을 확인하였으며, 이는 향후 NdFeB 폐자석 파분쇄 공정 설계 시 기초자료로 사용될 수 있을 것으로 판단된다.

• 산업융합연구
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• 제20권12호
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• pp.59-70
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• 2022

본 연구는 동일한 시장정보에 대하여 이익과 손실이라는 회계정보의 특성차이에 따라 회계이익에 반영되는 민감도가 차별적인지를 검증하였다. 이를 위해 Basu의 조건부 보수주의 측정치 및 Ball and Shivakumar의 보수주의 측정치를 활용하여 2012년부터 2020년까지 유가증권시장 및 코스닥시장에 상장된 비금융 상장기업 11,462개의 기업-연도별 자료를 분석대상으로 시장정보와 회계정보의 조합에 따라 회계이익 민감도를 분석하였다. 연구결과 경제적 이익에 대하여 이익기업과 손실기업 모두 지연 인식하는 것으로 나타난 반면, 경제적 손실에 대하여 손실기업은 신속하게 인식하고, 이익기업은 지연 인식하는 경향이 있음을 확인하였다. 이익기업과 비교하여 손실기업은 경제적 이익을 지연 인식하는 반면, 경제적 손실은 조기 인식함으로써 더욱 엄격한 보수주의가 적용되는 것을 확인하였다. 손실기업은 시장정보에 민감하게 반응하는 반면, 이익기업은 시장정보에 민감하게 반응하지 않음을 검증함으로써 시장정보와 회계정보의 결합효과와 비대칭적 적시성 간의 인과성에 대한 실증자료를 제공하고 있다.

• 한국분말재료학회지
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• 제20권5호
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• pp.359-365
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• 2013

In this study, we fabricated $Nd_2Fe_{14}B$ hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of $Nd_2Fe_{14}B$. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentrations of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to control the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of $Nd_2Fe_{14}B$ phase and magnetic properties was investigated.

• 디지털융복합연구
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• 제11권4호
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• pp.361-368
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• 2013

본 연구에서는 스프린터와 스케이터 패턴을 통합한 PNF 통합 패턴 운동이 만성 요통 노인 환자의 정적 균형과 동적 균형의 변화를 알아보고자 실시하였다. 본 연구는 만성 요통의 질환이 있는 노인 환자 34명을 대상으로 하였고, 34명을 무작위로 각각 PNF 통합 패턴 운동군(17명)과 스위스볼 운동군(17명)으로 나누었다. 운동전후에 정적 균형 능력 측정을 위해 GOOD BALANCE system(Metitur Oy, Palokka, Finland, 2003)을 사용하였다. 동적 균형 능력 측정을 위해 기능적 팔 뻗기 검사(functional reach test; FRT)와 일어나 걸어가기 검사(timed up and go test; TUG)를 시행하였다. 정적 균형 능력과 동적 균형 능력의 거의 대부분의 항목에서 유의한 차이를 나타내었다(p<.05). 군간 비교에서도 다수의 항목에서 스위스볼 운동군과 PNF 통합 패턴 운동군 사이에 유의한 차이를 나타내었다(p<.05). 이와 같은 연구 결과로 볼 때 PNF 통합 패턴 운동은 만성 요통 노인 환자의 균형 능력을 개선시키는데 효과적임을 알 수 있었으며, 임상에서 PNF 통합 패턴 운동을 이용할 수 있는 기초 자료를 충분히 제공하였다고 할 수 있을 것이다.

• 한국분말재료학회지
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• 제20권6호
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• pp.474-478
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• 2013

The most general photocatalyst, $TiO_2$ and $WO_3$, are acknowledged to be ineffective in range of visible light. Therefore, many efforts have been directed at improving their activity such as: band-gap narrowing with non-metal element doping and making composites with high specific surface area to effectively separate electrons and holes. In this paper, the method was introduced to prepare a photo-active catalyst to visible irradiation by making a mixture with $TiO_2$ and $WO_3$. In the $TiO_2-WO_3$ composite, $WO_3$ absorbs visible light creating excited electrons and holes while some of the excited electrons move to $TiO_2$ and the holes remain in $WO_3$. This charge separation reduces electron-hole recombination resulting in an enhancement of photocatalytic activity. Added Ag plays the role of electron acceptor, retarding the recombination rate of excited electrons and holes. In making a mixture of $TiO_2-WO_3$ composite, the mixing route affects the photocatalytic activity. The planetary ball-mill method is more effective than magnetic stirring route, owing to a more effective dispersion of aggregated powders. The volume ratio of $TiO_2(4)$ and $WO_3(6)$ shows the most effective photocatalytic activity in the range of visible light in the view point of effective separation of electrons and holes.

• Human Ecology Research
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• 제59권1호
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• pp.83-97
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• 2021

This study developed safety clothing that is essential for adolescent to protect their bodies from accidents, pursue activities and individuality. Therefore, the developed safety clothing was first based on international standards, while changing design to emphasize creativity, activity, and functionality. Two suits of boy's clothes and a girl's suit were developed as safety clothing for sportswear, along with two pairs of girl's clothes and a pair of boy's clothes for entertainment. It was confirmed that the difference in visibility was revealed by testing under different lighting conditions. Second, the survey on adolescents indicated no significant gender difference in sportswear. Round shirt+shorts for both boys and girls were the most preferred for ball game sportswear. However, there was a significant difference by gender in the design of safety clothing for entertainment. Male students preferred jump suit=cape+pants the most, and female students preferred jump suit>cape+pants in the order (p<0.05). In the safety clothes with the highest preference for entertainment, there was no gender difference. All students preferred the jump suit at the most. Checking at each school level, it was found that both middle and high school students preferred jump suit designs, and in safety clothing, middle school students preferred high-neck shirt blouse+tight skirt, and high school students preferred jump suits. Third, 35.5% responded that they would wear it more if current safety clothing is improved. This indicated the necessity of developing various safety clothing for adolescence.

• Journal of Sport and Applied Science
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• 제5권2호
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• pp.23-29
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• 2021

Purpose: The purpose of the study is to review the current states of new sports imported from foreign countries and to discuss strategic insights for promoting new sports which has been invented in Korea. Research design, data, and methodology: This study employed the qualitative approach, in which reviewed a related literature. First, the study selected flying disc, sports stacking, and T-ball as sample cases. This is because these new sports were recognized the prominent sports frequently played in physical education classes in Korea. Second, the study reviewed prior studies in the field of distribution and marketing in order to determine the criteria of analysis and variables that frequently examined in distribution and marketing studies. Finally, the study confirmed such terminologies as research variables including new sport name, organization name, background of the invented sports, distributional channel, promotional activities and so forth. To collect data, the study search literature via academic search engine including DBpia, KISS, RISS, ScienceDirect, SAGE Journals, SpringerLink, and Taylor & Francis. Results: It was found that all of the imported new sports organized association and its nationwide branches to deliver their sprots to local schools and recreational markets. second, they targeted schools and sought to broaden their markets to recreational communities. Conclusions: In order to promote new sport invented in Korea, associations need to be systematically organized and mission should be clearly stated. In addition, creative methods for promotion need to be developed. Future directions were discussed.

• 한국분말재료학회지
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• 제29권2호
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• pp.118-122
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• 2022

The synthesis of porous W by freeze-casting and vacuum drying is investigated. Ball-milled WO₃ powders and tert-butyl alcohol were used as the starting materials. The tert-butyl alcohol slurry is frozen at -25℃ and dried under vacuum at -25 and -10℃. The dried bodies are hydrogen-reduced at 800℃ and sintered at 1000℃. The XRD analysis shows that WO₃ is completely reduced to W without any reaction phases. SEM observations reveal that the struts and pores aligned in the tert-butyl alcohol growth direction, and the change in the powder content and drying temperature affects the pore structure. Furthermore, the struts of the porous body fabricated under vacuum are thinner than those fabricated under atmospheric pressure. This behavior is explained by the growth mechanism of tert-butyl alcohol and rearrangement of the powders during solidification. These results suggest that the pore structure of a porous body can be controlled by the powder content, drying temperature, and pressure.