• 한국콘텐츠학회논문지
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• 제10권8호
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• pp.461-471
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• 2010

최근, 현실세계와 가상세계를 결합하여 디지털 컨텐츠 형태로 보여주는 증강 현실 기술이 등장하고 있다. 증강현실 기술의 효과를 극대화하기 위해서, 사용자가 현실세계의 사물을 조작하는 것과 유사한 방법으로 디지털 콘텐츠와 상호작용하는 것을 가능하게 해 주는 실감형 인터페이스가 적용된다. 특히, 교육 분야에서는 이러한 기술들이 학습자의 흥미와 몰입도를 높이고, 학습 효과를 극대화할 수 있는 새로운 학습 콘텐츠의 제작을 가능하게 할 것으로 기대되고 있다. 본 논문에서는 멀티 터치스크린과 실감형 인터페이스를 적용한 과학 실험 학습 시스템을 제안한다. 이 시스템은 종래의 실험대 위에서 이루어지는 실험도구의 조작을 대체하기 위하여 대형 멀티 터치스크린을 장착한 실험 테이블과 간단한 사용자의 제스쳐를 인식할 수 있는 실감형 학습 디바이스를 사용한다. 실제 과학 실험에서는 높은 비용이나 긴 시간, 또는 위험 물질들이 요구되기도 하는데, 본 시스템은 이러한 요인들을 극복하면서 학습자들에게 다양한 실험을 현실감 있게 제공할 수 있다.

• Clinical and Experimental Pediatrics
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• 제60권5호
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• pp.138-144
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• 2017

Purpose: Following legal reform in 2013, the annual number of asylum seekers entering South Korea has increased from 1,143 in 2012 to 5,711 in 2015. We interviewed six African refugee mothers of young children regarding their health needs and barriers to access maternal child health services. Methods: We recruited mothers who had visited a clinic for immigrants between July 2013 and August 2015. Participants were African refugee women, aged over 18 years, who had given birth in Korea within the previous 5 years and had come to Korea over a year before recruitment. Interview questions examined participants' experiences in pregnancy and childbirth and concerns regarding their child's health status. Initial data analysis involved all researchers' immersion in the entire collection of transcripts. We then noted recurrent topics and themes and identified similar issues. Results: At the time of giving birth, 5 participants were asylum seekers and one had undocumented status. The following barriers impeded their access to maternal child healthcare: socioeconomic factors (unstable social identity, low economic status, difficulty obtaining health insurance), language barriers (lack of linguistically appropriate health information, limited access to translation services), and cultural barriers (religious and cultural differences). Weak social support also hindered access to healthcare soon after migration; however, social links with the community emerged as a key coping strategy following settlement. Conclusion: We identified barriers to maternal and child healthcare and coping strategies among African refugee mothers in Korea. Future research should assess refugees' health status and improve health access and literacy among refugee mothers.

• 한국멀티미디어학회논문지
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• 제8권10호
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• pp.1293-1305
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• 2005

본 논문에서는 HMD(head mounted display) 하단에 눈동자의 움직임 영상을 취득할 수 있는 USB 카메라를 부착한 후, 3차원 1인칭 슈팅(first Person shooting) 게임에서 게임 캐릭터의 시선방향을 눈동자 움직임에 의해 조작하는 방법을 제안한다. 본 논문에서 제안하는 방법은 다음과 같이 세 부분으로 구성된다. 첫 번째는 입력 영상으로부터 눈동자의 중심 위치를 실시간 영상 처리 방법으로 추출하는 부분, 두 번째는 HMD 모니터상의 임의 지점을 쳐다볼 때 추출된 눈동자의 위치 정보와 모니터상의 응시 위치 사이의 기하학적인 연관관계를 결정하는 캘리브레이션 부분, 그리고 마지막은 캘리브레이션 정보를 기반으로 모니터 상의 최종적인 응시 위치를 결정하고, 이 정보에 의해 게임상의 3차원 뷰(view) 방향을 조정하는 부분으로 구성된다. 실험 결과, 본 논문의 방법에 의해 손이 불편한 사용자에게 게임을 즐길 수 있는 기회를 제공하고, 게임 캐릭터와 게임 사용자의 시선 방향을 일치시킴으로서 게임의 흥미와 몰입감을 증가시키는 결과를 얻을 수 있었다.

• 한국수산과학회지
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• 제3권4호
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• pp.207-212
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• 1970

멸치절임의 숙성 및 저장 중의 효소 활성 VBN, 세균수, 식염 함유량, 산도, amino-N pH 그리고 지방의 산가에 다음과 같은 결과를 얻었다. 1) Protease 활성은 염수 염장 중에는 증가하고 절임 중에는 식초산의 영향으로 감소하고 이후 차차 거의 일정하게 변화하며 이에 따라 amino-N는 대개 증가하여 숙성한다. 2) Lipase 활성은 염수 염장 중에는 감소하며 vinegar의 첨가로 일단 증가하였다가 절임중에는 증감의 일정한 경향을 볼 수 없다. 그리고산도는 대개 증가하고 있다. 3) VBN와 NaCl 농도는 염수 염장 중에는 급격히 증가하고 절임중에서는 VBN는 완만한 증가를 하며 NaCl 농도는 기의 변화가 없었다. 4) 세균수는 염수 염장함으로써 줄었다가 다시 증가하며 절임함으로써 급격한 감소를 보이고 그 이후에는 일정한 수를 유지 하였다. 5) 절임 제품의 저장성을 유지하기 위해서는 육질의 산도가 $2\%$ 이상이 되도록 vinegar의 산도를 높혀 주어야한다. 6) 염수 염장하는 기간은 8일이 적합하였으며 VBN, 산도, amino-N, lipase 활성 및 관능 검사 성적을 보아서 절임한 후 47일까지 보장할 수 있고 32일 때가 가장 맛이 좋았다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권1호
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• pp.53-62
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• 2001

표면결함이 고밀도 폴리에틸렌 지오멤브레인의 열적 안정성과 응력균열저항성에 미치는 영향을 온도와 표면 결함 부여조건을 달리한 환경조건에서 역학적 특성, 화학저항성 및 피로시간을 측정하여, 조사하였다. 특별 고안된 장치를 사용하여 인위적으로 지오멤브레인 표면에 결함을 부여하였다. 표면결함은 표면결함 유도매체의 전단속도 100mm/min에서 표면결함 유도매체의 크기가 작을수록, 표면결함 부여횟수가 커질수록 증가하였다. 또한 이 조건에서 인장강도는 감소하였지만 인장신도는 증가하였다. 표면결함 부여조건이 같을 경우 고온으로 갈수록 그리고 침지시간이 길어질수록 인장강도는 감소되고 인장신도는 증가하여 표면결함이 부여된 지오멤브레인의 화학저항성은 저하되었다. 끝으로 응력균열저항성 시험 결과 온도가 높아질수록 표면결함이 부여된 지오멤브레인의 피로시간은 단시간 영역으로 이동되었다.

• Journal of the Korean Wood Science and Technology
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• 제46권4호
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• pp.355-361
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• 2018

In this study, the dimensional stability and mechanical properties of bamboo fiber-based composites (BFBCs) were studied at two pressing manufacturing processes, i.e., hot- and cold- pressing, and were compared with three density parameters (1.0, 1.1, and $1.2kg/m^3$). Width swelling ratio (WSR), thickness swelling ratio (TSR), and water absorption ratio (WAR) were calculated for water immersions of 4 and 28 h. WSR, TSR, and WAR for specimens immersed for 28 h were higher than those for 4 h treatment, which shows that the immersion time has a significant influence on the dimensional stabilities of BFBCs. Moreover, the positive linear relations between density and dimensional were observed at both the pressing ways, indicating that the WSR, TSR, and WAR decreased with an increase in the density of BFBCs. The compressive strength, shear strength, modulus of rupture (MOR), and modulus of elasticity (MOE) were determined. The compressive strength, MOR, and MOE of hot-pressed specimens were significantly higher than those for the cold-pressed specimens, which are also directly proportional to density. Moreover, the samples with the highest density of $1.2kg/m^3$ performed high values on mechanical properties in both the manufacturing methods.

• Journal of the Optical Society of Korea
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• 제15권3호
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• pp.252-263
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• 2011

In this work, for the first time, the quality of restoration in wide-field microscopy images after deconvolution was analyzed as a function of different Point Spread Functions using one deconvolution method, on a specimen of known size and on a biological specimen. The empirical Point Spread Function determination can significantly depend on the numerical aperture, refractive index of the embedding medium, refractive index of the immersion oil and cover slip thickness. The influence of all of these factors is shown in the same article and using the same microscope. We have found that the best deconvolution results are obtained when the empirical PSF utilized is obtained under the same conditions as the specimen. We also demonstrated that it is very important to quantitatively check the process' outcome using several quality indicators: Full-Width at Half-Maximum, Contrast-to-Noise Ratio, Signal-to-Noise Ratio and a Tenengrad-based function. We detected a significant improvement when using an indicator to measure the focus of the whole stack. Therefore, to qualitatively determinate the best deconvolved image between different conditions, one approach that we are pursuing is to use Tenengrad-based function indicators in images obtained using a wide-field microscope.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1222-1230
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• 2020

The corrosion rates of the reactor pressure vessel materials of SA508 Grade 3 were measured using a weight loss method in aerated boric acid solutions to simulate the evaporation of leaked PWR primary water in an ambient environment. The corrosion behavior and products were examined using X-ray diffraction and electron microscopy. SA508 showed typical general corrosion characteristics. The corrosion rate increased steadily as the boron concentration was increased. As the immersion time elapsed, the corrosion rate slowly or rapidly decreased according to the oxidation reaction of iron. The corrosion rate showed a complicated pattern depending on the temperature; it increased gradually and then rapidly decreased again when reaching a certain transition temperature. The corrosion products of SA508 were found to be FeO(OH), Fe₂O₃, and Fe₃O₄. As the boron concentration decreased and the temperature was increased, the formation of Fe₃O₄ was more favorable as compared to the formation of FeO(OH) and Fe₂O₃. Consequently, the changes of the corrosion rate and behavior were closely related to the oxidation reaction of iron on the surface. The corrosive damage to SA508 appears to be most severe when the oxidation reaction is such that Fe₂O₃ forms as a corrosion product.

• 대한치과보철학회지
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• 제37권5호
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• pp.597-606
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• 1999

This study was performed to evaluate the effect of aging and thermal cycling on the biaxial flexure strength of low commercially available veneering resin composites for crown(Dentacolor : DC, Artglass : AG, Esternia : ET and Targis : TG). Disc specimens were fabricated in a teflon mold giving 12mm in diameter and 1mm in thickness. All samples were divided into 4 groups. Group 1 was dried in a dessicator at $25^{\circ}C$ for 30 days. Group 2 was immersed in distilled water at $37^{\circ}C$ for 30 days. Group 3 was immersed in distilled water at $65^{\circ}C$ for 30 days. Group 4 was subjected to 10,000 thermal cycles between $5^{\circ}C\;and\;55^{\circ}C$, and the immersion time in each bath was 15 seconds per cycle. Biaxial flexure test was conducted using the ball-on-three-ball method at the cross head speed of 0.5mm/min and fracture surfaces were observed with scanning electoron microscope. The results obtained were summarized as follows; 1. Weibull modulus values, except for the AG group, decreased after thermal cycling treatment. 2. Biaxial flexure strength values of aging group at $37^{\circ}C$ were the lowest in all sample groups. Except for the DC group, strength values were significantly decreased for the drying group. 3. After thermal cycling test, the highest value of biaxial flexure strength of 188.8 MPa was observed in the ET group and the lowest value of 73.2 MPa was observed in the DC group. The strength values showed the significant differences in each group (p<0.05). 4. Observation of surfaces after thermal cycling test revealed the ditching in the part of surrounding large fillers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.412-412
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• 2008

ENIG(Electroless Nickel Immersion Gold)is a surface treatment method that is used most widely at fine pitch's SMT and BGA packaging process. ENIG has good diffusion barrier of Ni against solder and good wettability due to Au finish. But when the discoloration occurred on the Au finish of ENIG, some key characteristics related to the quality and reliability of PCB such as bondability, solderability and electrical flowing of packaging process could be deteriorated. In this paper, we have performed the water dip test ($88^{\circ}C$ purified water) which accelerates the galvanic corrosion of Ni diffused from the Ni-P layer. That is, the excessive oxidation of the Ni layer could result in non-wetting of the solder because the flux may not be able to remove excessive oxides. Though Au discoloration have been reported to be caused by Ni oxides in many literature, it is still open to verify and discuss The microstructures and chemical compositions have been investigated using FE-SEM, TEM, FIB, EDS and XPS. As a result, authors have found that the Au discoloration in ENIG type is severely caused by the oxidation of the Ni and the mechanism of Au discoloration can be confirmed through the experiment result of water dip test.