• ETRI Journal
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• 제15권2호
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• pp.69-74
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• 1993

The consumer surplus under the open economy is greater than that under the closed economy from the viewpoint of social welfare. This indication has been proved when only the product market is considered. This article is to show how this result is changed if the R&D market as well as the product market is considered. We find the possibility that the closed economy is preferred to the open economy in case of the (international) R&D joint venture.

• 한국정밀공학회지
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• 제29권3호
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• pp.313-318
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• 2012

Application of composite structures on naval ships strongly depends on the mechanical strength and collapse behavior of the T-joints of the whole structure. Because of the weight advantages over single skin composite and bolt fastening joining, three types of T-joints using both honeycomb sandwich composite and adhesive bonding were suggested to determine the effect of T-joint configuration. It was found that joining with a urethane foam block and overlaminates using the secondary co-bonding technique improves T-joint strength.

• 마이크로전자및패키징학회지
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• 제18권2호
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• pp.35-41
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• 2011

Recently, board level solder joint reliability performance of IC packages during drop impact becomes a great concern to semiconductor and electronic product manufacturers. The handheld electronic products are prone to being dropped during their useful service life because of their size and weight. The IC packages are susceptible to solder joint failures, induced by a combination of printed circuit board (PCB) bending and mechanical shock during impact. The board level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this paper, applying the JEDEC (JESD22-B111) standard present a finite element modeling of the FBGA. The simulation results revealed that maximum stress was located at the outermost solder ball in the PCB or IC package side, which consisted well with the location of crack initiation observed in the failure analysis after drop reliability tests.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제50권2호
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• pp.80-85
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• 2024

Objectives: To access the knowledge of undergraduate and postgraduate students of the dental college on basic anatomy, physiology, clinical examination, and pathology of the temporomandibular joint (TMJ). Materials and Methods: A total of 610 undergraduate and postgraduate students of dental college, were included in this study. The questionnaire was pretested for validation and distributed online through Google forms. Results: A pairwise comparison showed that the percentage of correct answers for interns significantly differed from that of IV Bachelor of Dental Surgery (P=0.050) and postgraduate students (P=0.048) (below average: up to 6 correct answers, good: 7-11 correct answers, excellent: 12 or more correct answers). Conclusion: TMJ diseases are common in daily life but frequently go undiagnosed and untreated due to a lack of clinical expertise. This demonstrates the necessity of providing instructions that give students in-depth knowledge and abilities for TMJ issues in clinical practice.

• ETRI Journal
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• 제33권2호
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• pp.155-162
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• 2011

The scalable extension of the H.264/AVC video coding standard (SVC) demonstrates superb adaptability in video communications. Joint source and channel coding (JSCC) has been shown to be very effective for such scalable video consisting of parts of different significance. In this paper, a new JSCC scheme for SVC transmission over packet loss channels is proposed which performs two-dimensional optimization on the quality layers of each frame in a rate-distortion (R-D) sense as well as on the temporal hierarchical structure of frames under dependency constraints. To compute the end-to-end R-D points of a frame, a novel reduced trellis algorithm is developed with a significant reduction of complexity from the existing Viterbi-based algorithm. The R-D points of frames are sorted under the hierarchical dependency constraints and optimal JSCC solution is obtained in terms of the best R-D performance. Experimental results show that our scheme outperforms the existing scheme of [13] with average quality gains of 0.26 dB and 0.22 dB for progressive and non-progressive modes respectively.

• 기술혁신학회지
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• 제3권2호
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• pp.94-110
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• 2000

This article prospects the patterns of technological innovation in the steel industry and suggests the directions of technological innovation in Korean steel industry. Technological innovation patterns can be analysed through technological trends, innovation-inducing mechanism, and innovators' relationships. In the technological trends, direct coupling of manufacturing processes, lasting growth of mini-mill, and the importance of technological integration are prospected. In the innovation-inducing mechanism, while production system will be specialized, the development of new steel materials and environment-friendly technological innovation will be accelerated. In the innovators' relationships, steel industry faces more complex competition and new forms of inter-firm cooperation including M&A, joint venture, and joint R&D. In order to cope with such changes in the technological innovation patterns, Korean steel industry need to establish core competence based on technological innovation through a great leap in R&D investment, the production of high value-added products, the development of new generation steel technologies, strategic joint R&D, comprehensive technological cooperation, and government's active support.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.335-336
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• 2006

초고압 지중송진선로에 적용되는 가교절연케이블은 전기적 특성의 우수성과 유지보수의 용이성 때문에 확대적용되고 있다. 345kV급 지중송전선로는 장거리 계통에 적용이 되고 있으며, 이에 따라 접속재 부분의 개발이 중요하게 되었다. 현재 154kV용 PMJ는 자체 개발되어 실계통에 설치 운용되고 있다. 345kV급 PMJ개발에 앞서 220kV급 가교절연 송전선로용 PMJ를 자체 설계 및 제조하여 세계적인 인증기간인 KEMA에서 제품의 신뢰성 인증을 받았다.

• 기술혁신학회지
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• 제15권2호
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• pp.400-420
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• 2012

본 연구는 국가연구개발사업의 지원을 받는 기초 및 원천단계의 연구과제를 대상으로 국제공동연구성과를 제고할 수 있는 방안을 검토한다. 연구방법으로는 연구결과의 객관성과 보편 타당성을 확보하기 위해 1단계에서 질적 접근과 양적 접근을 포함한 혼합적 접근 방법이 채택한다. 분석결과 국제공동연구의 영향 요인으로는 SCI 논문 건수, 국내외 학술회의 참가, 박사급 연구인력의 참여로 요약될 수 있다. 2단계는 1단계에서 도출된 결과를 토대로 국제공동연구 성과를 제고할 수 있는 방안을 자료포락분석법을 통해 분석하는데, 분석결과 사업별로 성과 제고 방안이 다양하게 도출되며 정부연구비나 과제수의 증가가 절대적인 영향을 주지 않는다는 결론을 살펴볼 수 있다. 요컨대 본 연구는 단계별 분석을 통해, 연구비 투자를 포함한 투입요소가 반드시 국제공동연구 성과에 비례하지 않음을 살펴볼 수 있고, 국가연구개발사업의 세부 사업별 특성과 목표에 따라 달성하고자 하는 성과와 운영 방식이 재정립되어야 할 필요가 있음을 제시한다는 점에 의의가 있다.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권2호
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• pp.153-165
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• 2013

기존의 보행분석 연구들은 하지를 하나의 스프링으로 간주하였다. 만약 슬관절 신전을 보조할 수 있는 슬관절 액추에이팅 메커니즘을 개발할 수 있다면 보행에 필요한 탄성-변형률에너지를 혁신적으로 저장-방출할 수 있고, 그 결과 보행 중 하지강성은 더욱 증가할 것이다. 게다가 족관절 액추에이팅 메커니즘까지 추가되어 있다면 슬관절 액추에이터에 의한 과도한 인공하지강성을 능동적이고 적절한 수준으로 보상해주는 기전으로 작동할 것이다. 만약 가속도에 의한 보행속도 증가를 방지하기 위해 인위적 감속통제를 작동시킨다면 불필요한 운동에너지의 방출이 발생되고 하지강성 액추에이터의 실효성은 의심을 받게 된다. 따라서 본 저자는 보행속도를 2개의 세그먼트에 의한 상대 각속도 조절기법을 이용하여 하지강성을 증가시킨다는 기본개념으로 슬-족관절 액추에이터 시스템을 개발하였다. 또한 족관절에 슬관절 액추에이팅에 대한 보상기전이 존재하는 경우, 족관절의 보상기전이 중족지절관절 경사각 및 보행속도 변화에 미치는 상호영향을 연구하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1413-1414
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• 2013