• 한국컴퓨터정보학회논문지
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• 제17권10호
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• pp.137-143
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• 2012

학습자들은 스마트 디바이스를 이용하여 언제 어디서나 인터넷 접속을 통한 각종 학습처리까지 가능하다. 일상생활에서 계속적으로 스마트 디바이스를 이용할 수 있는 인터넷의 자유를 얻는 만큼 학습자들의 다양한 학습(learning) 서비스 요구와 이용 또한 활발해 진 것이다. 이점에서 요구하는 학습의 관련된 자료들을 동시에 제공할 수 있는 조화로운 융합형 학습 서비스를 제공하는 새로운 이-러닝 연구의 필요성이 높아지고 있다. 융합형 학습 서비스는 하나의 혹은 여러 디바이스를 통해 복합 미디어를 구성하는 각각의 콘텐츠간의 조화로운 동기화는 중요 조건이다. 현재는 대표적으로 융합미디어간의 동기화를 제공하는 방법은 콘텐츠간 절대적인 시간 값을 맞추는 방법이다. 그러나 이 방법은 콘텐츠를 전송시 시간적인 딜레이 발생한다. 또한 콘텐츠의 지속시간에 대한 절대적인 시간값을 직접 입력해야하는 번거로움이 있으며, 콘텐츠 작성 시 여러 문제들이 발생한다. 본 논문에는 동기화 문제를 해결 할 수 있는 내용에 따른 하모나이징 동기화 기법 모델(Harmonizing Sync Model)을 제고하고자 한다. 내용에 따른 동기화 기법은 학습 콘텐츠를 집합관계를 효과적으로 모델링 하여 다양한 학습 융합미디어를 갖춘 스마트러닝 개념이다.

• 한국과학예술포럼
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• 제19권
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• pp.623-633
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• 2015

Use of technology through utilization of ICT (Information Communication Technology) in field study area is rapidly increasing. Thus, when applying ICT to experiential education, apart from experiential education contents in simple form, the demand for new high quality contents is increasing considering change in education paradigm focusing on creativity. As a result, high quality interactive experiential education content for developing self-directed future talents is required. As a result of this, the development of ARD-based ICT experiential education content system that enhances learning effect of students by integrating ARD-based (Augmented Reality Display) ICT and experiential education to promote existence and immersion is being tested. This paper aims to improve efficacy and achieve vitalization through case analysis of AR-based ICT experiential education content. As a result of case analysis, the composition of content for improving education content included 1) constant securing and strengthening of experiential education content, 2) necessity for development of participating education content by diverse age groups, 3) development of differentiated ICT experiential education content, and 4) securing professional manpower and development of content in connection with education process. Therefore, with the efficacy of ARD-based ICT experiential education content, this study can first, enhance bond between students, second, enable self-directed learning, third, increase practical understanding in contents that were difficult to control by textbook contents, and fourth, increase interest and immersion in learning. Therefore, the contents on new converging technology that can maximize the development of constant content and cooperation between ICT technology and pedagogy for educating creativity and autonomy of ICT experiential education content.

• 한국레이저가공학회지
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• 제7권3호
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• pp.25-36
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• 2004

This study was performed to clarification of the formation of weld discontinuities in the dissimilar laser fusion zone. Welding parameters were beam power of 1300, 1430, 1560, and 1700 W and travel speed of 1, 1.3, and 1.7 m/min. Most cavities in the fusion zone were observed near the tip. Cavities in the fusion zone observed to be formed and grown from pores in the tip. More cavities were formed as the beam position moves to the tip side. Small cavities were decreased but large cavities were increased when the energy input increased. W content in the fusion zone was increased with heat input and as the beam position close to the tip. In the fusion zone, W content in the dendrite boundary was increased with heat input. Considering the propagation path and fracture morphology, cracks were solidification cracking, and were initiated and propagated along the dendrite boundaries. The formation of cracks might be related with the W rich ${\mu}$ phase which was formed in the grain boundaries and dendrite boundaries.

• Journal of Welding and Joining
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• 제18권1호
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• pp.59-69
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• 2000

The purpose of the present study was to investigate weld metallurgical phenomena such as primary solidification mode, microstructural evolution and hot cracking susceptibility in nitrogen-bearing austenitic stainless steel GTA welds. Eight experimental heats varying nitrogen content from 0.007 to 0.23 wt.% were used in this study. Autogenous GTA welding was performed on weld coupons and the primary solidification mode and their microstructural characteristics were investigated from the fusion welds. Varestraint test was employed to evaluate the solidification cracking susceptibility of the heats and TCL(Total Crack Length) was used as cracking susceptibility index. The solidification mode shifted from primary ferrite to primary austenite with an increase in nitrogen content. Retained delta ferrite exhibited a variety of morphology as nitrogen content varied. The weld fusion zone exhibited duplex structure(austenite+ferrite) at nitrogen contents less than 0.10 wt.% but fully austenitic structure at nitrogen contents more than 0.20 wt.%. The weld fusion zone in alloys with about 0.15 wt.% nitrogen experienced primary austenite + primary ferrite solidification (mode AF) and contained delta ferrite less than 1% at room temperature. Regarding to solidification cracking susceptibility, the welds with fully austenitic structure exhibited high cracking susceptibility while those with duplex structure low susceptibility. The cracking susceptibility increased slowly with an increase in nitrogen content up to 0.20 wt.% but sharply as nitrogen content exceeded 0.20 wt.%, which was attributed to solidification mode shift fro primary ferrite to primary austenite single phase solidification.

• KSBB Journal
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• 제5권3호
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• pp.255-261
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• 1990

Astaxanthin을 생산하는 효모 Phaffia rhodozyma로부터 제조된 상보적 돌연변이 균주간의 세포융합을 통하여 astaxanthin을 대량 생산하는 균주를 얻고자 시도하였다. 이들의 원형질체 융합빈도는 $1.3$\times$10^-^5-6.0$\times$10^-^5$이었고 DNA함량, 핵염색, UV조사에 대한 생존력 비교 그리고 형질분리분석등으로 핵융합을 확인하였다. 융합체 중 F1은 야생형의 모 균주와 비교했을때 astaxanthin생성량이 약 3배 증가하였다.

• 폴리머
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• 제35권3호
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• pp.189-195
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• 2011

조직 형성을 위한 생리학적 환경을 제공하는 새로운 생활성 지지체의 디자인은 생체재료 연구에서 중요한 분야이다. 본 연구에서는 3차원적 실크/PLGA 지지체의 물성평가를 위해 압축강도, 수분친화도, SEM 분석을 하였으며, 세포친화성 평가를 위해 RAW 264.7과 NIH/3T3의 부착, 증식 및 표현형유지와 염증반응에 미치는 영향을 조사하였다. 지지체는 용매 캐스팅/염 추출법으로 제조하였고, 압축강도, 수분친화도 면에서 실크 함량이 20 wt%에서 우수함 확인했으며, 표면의 거침도활 높여 세포부착에 긍정적인 구조임을 확인하였다. 세포친화성 분석 결과 실크함량이 20 wt%인 실크/PLGA 지지체에서 높은 초기부작도 및 증식률을 보였으며, 실크함량이 20 wt%에서 염증반응이 눈에 띄게 감소함을 확인하였다. 조직공학적 응용에 실크/PLGA 지지체가 유용할 것이라 판단하였다.

• 폴리머
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• 제35권2호
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• pp.113-118
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• 2011

고체분산체는 난용성약물의 용해도를 향상시키는 기술로 용출특성을 고분자의 성질, 고분자의 함량 및 물리화학적 성질에 의하여 변화한다. 본 연구에서는 이부프로펜과 셀룰로오스 아세테이트를 사용하여 분무건조와 로터리 증발법을 사용하여 고체분산체를 제조하였다. 제조한 고체분산체의 표면성질을 주사전자현미경(SEM)을 사용하여 분석하였으며, X선 회절기(X-RD)와 사치주사열량계(DSC)를 사용하여 결정성 변화를 관찰하였다. 고체분산체의 화학적 변화를 관찰하기 위하여 적외선 분광기(FTIR) 분석을 하였으며, 수분 친화도를 측정하기 위하여 수분접촉각 측정을 하였다. 용출 특성은 인공정액(pH 6.8) 및 인공위액 (pH 1.2)에서 관찰하였다. 실험결과 약물의 결정성은 고분자의 비율이 증가하면 결정성이 감소하였으며, 화학적 변화는 없었다. 수분 친화도는 고분자비율과 비례하였으며, 분무건조로 제조된 고체분산체의 경우가 조금 높은 수분 친화도를 가졌다. 용출실험 결과 인공위액에서는 고분자의 비율이 높아질수록 용출률이 증가하였으며, 인공장액에서의 용출속도는 고분자의 비율과 반비례하는 것을 볼 수 있었다.

• 미생물학회지
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• 제29권2호
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• pp.123-129
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• 1991

In order to develop the protoplast fusion method of the strains of Fusarium, the interspecific protoplast fusion was attempted between Fusarium poae and F. sporotrichioides. Various auxotrophic mutants were isolated by the treatment of N-Methyl-N'-Nitro-N-Nitrosoguanidine. The optimal conditions for the formation and regeneration of protoplasts were examined and the characteristics of a fusant were studied. As a results, protoplasts were readily obtained from 18 hours cultured mycelia by the treatment of driselase for 3 hours and 0.6 M KCl as a best osmotic stabilizer at pH 6.0 for the formation of protoplast. Sucrose was the most suitable for the regeneration. Polyetylene glycol (M.W. 8,000) in $CaCl_{2}$-glycine solution was used to induce the protoplast fusion. The interspecific fusion frequency between protoplasts among the auxotrophic mutants of the two strains ranged from $2.7*10^{-2}$ to $5.7*10^{-3}$ . DNA content and cellulase activity were rather increased in the interspecific fusant. The lag phase of growth curve was slightly elongated in the fusant.

• Journal of Microbiology and Biotechnology
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• 제2권1호
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• pp.46-49
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• 1992

The availability of Phaffia rhodozyma as an astaxanthin sources in the aquaculture industry is limited because of the low carotenoid content of natural isolate. In this study, we have used the protoplast fusion technique to construct cell hybrids with an increased content of astaxanthin from P. rhodozyma. Cell hybrids (F307 and F406) obtained were very stable and produced considerably more astaxanthin (> 1 mg/g yeast) than the wild parent. Karyogamy was confirmed by the isolation of recombinants after mitotic segregation of parental auxotrophic genetic markers, the increased amount of chromosomal DNA/cell and the presence of single nucleus/cell.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1232-1237
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• 2008

This paper introduces an application of wavelet analysis to the sensor fusion of GPS/INS/baroaltimeter. Using wavelet analysis the baro-inertial altitude is decomposed into the low frequency content and the high frequency content. The high frequency components, 'details', represent the perturbed altitude change from the long time trend. GPS altitude is also broken down by a wavelet decomposition. The low frequency components, 'approximations', of the decomposed signal address the long-term trend of altitude. It is proposed that the final altitude be determined as the sum of both the details of the baro-inertial altitude and the approximations of GPS altitude. Then the final altitude exclude long-term baro-inertial errors and short-term GPS errors. Finally, it is shown from the test results that the proposed method produces continuous and sensitive altitude successfully.