• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2003년도 봄 학술발표대회논문집
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• pp.268-269
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• 2003

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.73-117
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• 2004

Software 기술의 변화: 다중프로그래밍, 다중 사용자(multiuser), 실시간처리/데이터베이스, 제품소프트웨어 출현, 강력한 데스크-탑 시스템, 객체지향 시스템, 전문가 시스템, 인공지능(중략)

• 대한치과의사협회지
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• 제54권7호
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• pp.563-574
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• 2016

A clear overlay appliance is a type of a removable appliance made from transparent thermoplastic plastic film that covers the entire dentition to move the teeth. It is one of the most favored orthodontic methods opted for by adult patients; this treatment is esthetic, does not cause discomfort and allows oral hygiene to be easily managed when compared to other conventional fixed treatment methods. However, the use of clear overlay appliances, such as invisalign or clear aligner, is associated with various clinical challenges. In particular, the appliances require longer treatment periods compared to fixed treatment, and due to the structural characteristics of the appliances, it is difficult to make proper posterior occlusion and certain type of tooth movement, including extrusion, rotation and tip. Thus, the clear overlay appliances are regarded as supplementary appliances by most orthodontists and have been used for simple orthodontic treatments, such as partial anterior alignments or orthodontic relapse cases. Owing to the remarkable advancement in the field of 3D digital technology over a period of 15 years, the accuracy and convenience of modern clear overlay appliances have continuously improved. Moreover, orthodontic outcomes have also been greatly improved by the introduction of new materials and successful application of various biomechanical methods from conventional orthodontic treatments in the design of clear overlay appliances. This study investigates the clinical limitations that should be considered during the application of clear overlay appliances and also examines the efforts and methods used to overcome these challenges.

• Journal of Mechanical Science and Technology
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• 제18권2호
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• pp.185-192
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• 2004

The aeroacoustic characteristics of a centrifugal fan for a vacuum cleaner and its noise reduction method are studied in this paper. The major noise source of a vacuum cleaner is the centrifugal fan. The impeller of the fan rotates at over 30000 rpm, and generates very high-level noise. It was revealed that the dominant noise source is the aerodynamic interaction between the rotating impeller and stationary diffuser. The directivity of acoustic pressure showed that most of the noise propagates backward direction of the fan-motor assembly. In order to reduce the high tonal sound generated from the aerodynamic interaction, unevenly pitched impeller and diffuser, and tapered impeller designs were proposed and experiments were performed. Uneven pitch design of the impeller changes the sound quality while the overall sound power level (SPL) and the performance remains similar. The effect of the tapered design of impeller was evaluated. The trailing edge of the tapered fan is inclined. This reduces the flow interaction between the rotating impeller and the stationary diffuser because of some phase shifts. The static efficiency of the new impeller design is slightly lower than the previous design. However, the overall SPL is reduced by about 4 dB(A). The SPL of the fundamental blade passing frequency (BPF) is reduced by about 6 dB (A) and the 2$\^$nd/ BPF is reduced about 20 dB (A). The vacuum cleaner with the tapered impeller design produces lower noise level than the previous one, and the strong tonal sound was dramatically reduced.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1341-1346
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• 2008

This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.788-793
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• 2008

This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.189-193
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• 2008

Performance of refrigerant oil at the thrust-bearing and at the journal-bearing of a scroll compressor is a significant factor. This paper presents the friction and anti-wear characteristics of nano oil with a mixture of a refrigerant oil and carbon nano particles in the journal bearing of scroll compressors. The characteristics of friction and anti-wear using nano-oil is evaluated using the disk on disk tester and the journal bearing tester for measuring friction surface temperature and the coefficient of friction at the journal bearing tester. In journal bearing test, the average friction coefficient of high concentration nano-oil was decreased down to 18% compared to raw oil under 4,500 N and 3,600 rpm. It is believed that nano particles can be coated on the wear surfaces and the interaction of nano particles between surfaces can be improved the lubrication in the friction surfaces. Worn surfaces of frictional specimen were measured with straightness. carbon nano oil enhances the characteristics of the anti-wear and friction at the joural bearing of scroll compressors.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2000년도 추계 학술발표대회 논문집
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• pp.28-29
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• 2000

디지털(digital) 기술의 발전에 의해 주도되고 있는 정보 혁명이 과거 어느 때 보다도 강력하고 빠르게 인류 역사의 흐름을 변화시키고 있음은 부인할 수 없는 사실일 것이다. 디지털 환경은 제품의 기능 및 디자인의 기대 가치에 직간접적으로 영향을 미치며 디자인 대상인 제품의 의미, 사용자와의 관계 등에 관한 재해석을 요구하고 있다.(중략)

• 한국콘텐츠학회논문지
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• 제14권12호
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• pp.924-934
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• 2014

지난 10년 동안 디지털 음악콘텐츠 시장은 급속도로 확산되고 있으나 다양한 음원 상품과 서비스 상품에 대한 소비자 사용 및 소비에 영향을 미치는 음악콘텐츠 상품의 가치 요인들을 고려한 상품 구성과 가격 정책에 대한 자료는 미비한 실정이다. 이에 본 연구에서는 현재 국내에서 이루어지는 스트리밍과 다운로드 방식의 디지털 음악콘텐츠 서비스 상품을 중심으로 소비자의 서비스 상품 선택에 영향을 미치는 속성으로 장르, 가격, 음질, 이용기기를 정의하고, 헤도닉 가격모형이론과 컨조인트 분석방법을 통해 소비자가 지각하고 있는 속성 요인별 중요도와 부분 가치를 추정하여 디지털 음악콘텐츠 서비스에 대한 소비자 중심의 시장가격과 상품 구성에 대한 전략적 시사점을 제시하고자 했다. 이를 위해 국내 디지털 음악콘텐츠 서비스 사용자 405명의 설문조사를 실시하였으며, 분석 결과 다운로드 방식에서는 '음질' 속성이 스트리밍 방식에서는 '이용기기' 속성이 '가격' 속성보다 중요하게 나타났다. 결론적으로 디지털 음악콘텐츠 서비스 상품 구성 및 가격 책정의 경우 생산자 중심의 가치에 대한 고려를 넘어 소비자 중심의 시장과 소비 속성을 고려한 차별화가 이루어질 수 있어야 함을 살펴볼 수 있었다.

• 한국컴퓨터정보학회지
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• 제15권1호
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• pp.37-46
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• 2007

최근에는 IT기술의 발전으로 다양한 기능을 하는 모바일 정보 기기의 보급이 많이 늘어나고 있는 추세이다. 모바일 정보기기의 대표적인 휴대폰을 이용하여 더 편리하고 효율적인 생활 및 업무를 하는 순기능도 있지만, 휴대폰을 이용한 첨단기술자료 유출, 개인의 프라이버시 침해, 공갈 및 협박 등의 범죄의 수단으로 활용되는 역기능도 나타나게 되어 문제점들이 많이 나타나게 되었다. 하지만 이러한 휴대폰을 이용한 범죄에 대해서는 법령 미비 등의 법적 연구도 부족할뿐더러 수사 관점에서도 삭제, 복사, 이동이 쉬운 디지털증거의 특성상 객관적인 증거로 보장하기 위한 디지털증거의 무결성을 입증하기 위한 연구와 노력이 필요하게 되었다. 이러한 디지털 포렌식 분야를 모바일 포렌식 이라고 한다. 본 논문에서 모바일 포렌식의 대표격인 휴대폰을 통하여 일어날 수 있는 디지털증거의 획득 방안에 대하여 실제 검증해보고 해쉬함수를 이용하여 디지털증거의 무결성을 입증하는 방안을 제시하는데 목적이 있다.