• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.67-83
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• 2007

The characteristics of steady two-dimensional laminar boundary layer flow of a viscous and incompressible fluid past a moving wedge with suction or injection are theoretically investigated. The transformed boundary layer equations are solved numerically using an implicit finite-difference scheme known as the Keller-box method. The effects of Falkner-Skan power-law parameter (m), suction/injection parameter ($f_0$) and the ratio of free stream velocity to boundary velocity parameter (${\lambda}$) are discussed in detail. The numerical results for velocity distribution and skin friction coefficient are given for several values of these parameters. Comparisons with the existing results obtained by other researchers under certain conditions are made. The critical values of $f_0$, m and ${\lambda}$ are obtained numerically and their significance on the skin friction and velocity profiles is discussed. The numerical evidence would seem to indicate the onset of reverse flow as it has been found by Riley and Weidman in 1989 for the Falkner-Skan equation for flow past an impermeable stretching boundary.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1998년도 춘계 학술발표회 논문집
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• pp.235-242
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• 1998

Aiming at one of decisive alternatives for long term aspect of nuclear power concerns, an integral and closed nuclear system, AMBIDEXTER (Advanced Molten-salt Break-even Inherently-safe Dual-mission Experimental and TEst Reactor) concept is under development. The AMBIDEXTER complex essentially comprises two mutually independent loops of the radiation/material transport and the heat/energy conversion, centered at the integrated reactor assembly, which enables one to utilize maximum benefits of nuclear energy under minimum risks of nuclear radiation. And it provides precious radioisotopes and radiation sources from its waste stream. Also the reactor operates at very low level of fission products inventory throughout its lifetime. The nuclear and thermalhydraulic characteristics of the molten TH/$^{233}$ U fuel salt extend the capability of the self-sustaining AMBIDEXTER fuel cycle to enhance resource security and safeguard transparency. The reactor system is consisted of a single component module of the core, heat exchangers and recirculation pumps with neither pipe connections nor active valves in between, which will significantly improve inherent features of nuclear safety. States of the core technologies associated with designing and developing the AMBIDEXTER concept are mostly available in commercialized form and thus demonstration of integral aspects of the concept should be the prime area in future R＆D programs.

• 한국의류산업학회지
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• 제8권2호
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• pp.168-176
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• 2006

The court dancing suit, so-called 'Jeongjae suit', has been worn by court dancers on the occasion of the royal court's feasts or festivals such as auspicious events of a country, court banquets, and parties or receptions for national guests from foreign countries. The court dancing suits are divided into two styles; Dangak-Jeongjae style and Hyangak-Jeongjae style, depending on dancing styles. This study examined the change of the dancing suits of Hyangak-Jeongjae styles created in the latter period of Joseon Dynasty, such as Bosangmu, Cheomsumu, Heoncheonhwa, and discussed the thought of EumYang-Ohaeng(the cosmic dual forces and the five elements) that the colors of the court dancing suits imply. Generally, in the dancing suits of Bosangmu, Cheomsumu, and Heoncheonhwa, the color expression focused on the main stream of red, blue, yellow, white and black. The colors were mainly expressed in harmony between upper garments and under garments, outer garments and inner garments, a simple dress and its decorations. Especially, in the dancing suits of Heoncheonhwa, the purple color symbolized the auspiciousness of the Purple Palace where the God lives.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 추계학술발표대회 및 정기총회
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• pp.743-746
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• 2005

본 논문에서는 디지털 비디오 인코딩 과정의 VLC(variable length coding) 영역에서 블록계층의 DC/AC 성분을 이용한 인증과 서명의 이중 비디오 워터마킹 시스템을 제안하였다. 제안한 기법은 블록계층의 DC 성분과 AC 성분에서 HVS(human visual system)의 특성을 고려한 것이다. 인증 워터마킹은 주요한 정보를 포함하는 저주파 영역과 윤곽선 정보를 포함하는 중간 주파수 영역을 이용하여 인트라 프레임의 DC 성분과 움직임 벡터의 부호를 변형시켰고, 서명 워터마킹은 모든 프레임의 AC 성분들 중에서 마지막 AC 성분의 Level이 '1'인 경우에만 워터마크를 삽입하였다. 서명 워터 마크 검출은 저작권자의 비밀 키에 의해서만 가능하고, 기술적인 면에서 저자권자의 판별 기준이 될 수 있다. 제안한 이중 비디오 워터마킹 시스템의 특징은 인증과 서명의 두 가지 기능을 선택적으로 수행할 수 있으며, 계산과정이 복잡하지 않으면서 비트 스트림(bit-stream)을 유지시킨다. 그리고 실험 결과에서 기존의 방법보다 화질 면에서 $2{\sim}3dB$ 더 높은 수치를 얻어 우수함을 보였고, 인코딩 수행 속도에 미치는 영향은 거의 없었으며, 향후 실시간 인코딩 처리에 응용될 수 있다.

• 한국추진공학회지
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• 제12권5호
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• pp.1-8
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• 2008

소형 액체로켓엔진 인젝터 분무의 공간분포 특성 규명을 위해 이중모드 위상도플러속도계(DPDA)를 이용한다. 분사압력 및 분무확산방향 이동거리를 변화시켜 분무액적의 크기, 속도 등을 측정하고, 산술평균직경(AMD), Sauter 평균직경(SMD), 수밀도, 스팬(span of drop size distribution), 그리고 체적 유속(volume flux) 등의 분무 매개변수를 도출하여 인젝터 분무의 분열특성을 고찰한다. 분사압력이 증가함에 따라 분무액적의 수밀도, 스팬, 그리고 체적 유속은 증가하지만, AMD는 감소하였다.

• International Journal of Automotive Technology
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• 제5권1호
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• pp.9-16
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• 2004

An experimental study was carried out to characterize the spray atomization process of micro-machined port fuel injectors with a piezoelectric atomization device, which can generate pressure pulsations through vibration of a piezoelectric transducer. In this study, several types of micro-machined arrays such as 30∼200-microns of hole arrays were tested. Both a dual-stream and a central-port injectors with micro-machined arrays were tested and compared with normal port fuel injectors. The spray visualization was conducted to characterize overall spray structure and phase Doppler particle analyzer (PDPA) system was used to quantify the droplet size and velocity. In addition, the pressure history was recorded by using digitized signal from pressure transducer. The results showed that modulation is effective to the spray atomization for tested injectors and atomization performance depends on injector design factors, orifice sizes, and frequency and power of the modulator. A number of resonance frequencies of the modulator was modified by injector parameters and temperature. In addition, our results suggested that design of sufficient space among holes is critical to avoid droplet coalescence in the multi-hole micro-machined injectors.

• Membrane and Water Treatment
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• 제3권2호
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• pp.113-121
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• 2012

Up-flow multi-layer bioreactor (UMBR) is a hybrid system using dual sludge that consists of an up-flow multi-layer bioreactor as anaerobic/anoxic suspended growth microorganisms followed by an aeration tank. The UMBR acts as a primary settling tank, anaerobic/anoxic reactor, thickener which requires low energy due to mixing by up-flow stream. This study focused on using a pilot UMBR plant with capacity of 20-30 $m^3$/day for domestic wastewater in HCMC. HRTs of UMBR and aeration tank were 4.8 h and 7.2 h, respectively. The average MLSS of UMBR ranged from 10,000-13,600 mg/l SS. Internal recycle rate and sludge return were 200-300% and 150-200%, respectively. The results obtained from this study at flow rate of 20 $m^3$/day showed that removal of COD, SS, TKN, N-$NH_4$, T-N, and color were 91%, 87%, 86%, 80%, 91% and 91%, respectively.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.340-343
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• 2005

본 논문은 유로 가입자에 대해서 수신이 가능하도록 제한하는 제한수신시스템을 적용한 디지털멀티미디어방송 수신시스템 구현에 관한 연구이다. 이 시스템은 스마트카드와 소프트웨어 기법의 제한 수신시스템을 사용하여 스크램블 된 전송 스트림을 역스크램블 하기 위한 제어단어를 추출하므로 강화된 안전성을 제공한다. H.264의 비디오 데이터 복호화 처리를 위한 DSP와 RISP가 있는 듀얼 프로세서를 사용하여 QVGA의 비디오와 24Khz${\sim}$48Khz의 오디오 방송을 평균 15f/s로 재현이 가능하다. 가입자 정보를 추가한 방송 스트림을 수신하여 제한수신의 동작 상태와 역스크램블 된 스트림을 디코딩하였을 때 정상 가입자에 대한 경우 역스크램블 과정이 정상적으로 수행되었음을 확인할 수 있었다.

• 정신신체의학
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• 제7권1호
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• pp.10-25
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• 1999

2세이상의 어린이는 성적 흥분을 느낄 수 있기에 만지거나 자위행위 등의 성적인 즐거움을 찾기 시작 한다. 60년대 후반부터 70년대 초반사이 산부인과 의사 Masters와 사회사업가 Johnson은 인간의 성반응 단계를 흥분기, 고원기, 오르가슴기, 반응소실기의 4단계로 나눠 설명하였고, 여성에게는 무반응기가 없어 여러번의 오르가슴이 가능함을 밝혔다. 그들의 성치료원칙은 행동치료에 입각하여 감각초점법과 부부치료, 성교육등으로 구성되어있다. Masters와 Johnson이후 정신과 의사이자 정신분석가인 Kaplan이 1970년대 초반에 정신분석적 정신치료와 행동치료를 결합한 '새로운 성치료'를 제안했다. 그리고, 성기능 장애를 3가지 카테고리로 재분류했다. 1980년대 이후는 남성의 발기부전의 치료를 중심으로 의학적 치료방법론이 대세를 이루고 있는데, 음경 보속물, 국소주사치료, 경구약제등이 발달하였다. 최근 Sildenafil(Viagra)이 등장해 남성 발기부전 치료의 최선의 선택으로 받아들여지고 있다.

• 사상체질의학회지
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• 제9권1호
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• pp.1-12
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• 1997

Neiging Medicine(內經醫學) based on Yin-Yang and Five elements was the main stream of Korea Traditional Medicine until the end of 19th century. And the establishment of Sasang Constitutional medicine. In this paper, author proved that the Yin-Yang of Sasang Constitutional Medicine was different from that of Neiging Medicine and that explained the Yin-Yang of Sasang Constitutional Medicine as our own medicine. After considering the philosophical and medical background of Sasang Constitutional Medicine, and author researched the Yin-Yang of ontology, structure, function, symptoms in Sasang Constitutional Medicine. Also we compared this with that of Neiging medicine. The results were as follows 1. Neiging Medicine was based on the Yin-Yang and Five elements centering on the nature and Sasang joy, and pleasure centering on the human. 2. The ontology of Sasang Constitutional Medicine were the mind as a unitary substance, the mind and body as a dual substance, and affair, mind, body, and objects as a four substance which were the basic theory of philosophy. 3. Sasang Constitutional Medicine explained social phenomenon with a four substancial structure consisted of affairs, mind, body, and objects, a complex four substancial structure consisted of heaves, human, nature and order, and a three dimension structure including time. 4. On the other hand Neiging Medicine recognized seven emotions as five emotions, Sasang Constitutional Medicine recognized seven emotions as qi, nature, and emotions which consisted of sorrow, anger, joy, and pleasure. The qi had an effect on internal and external part of body and the nature and the emotion had an effect on the upward and downward of body. 5. It was taked great importance to control the up and down balance and the internal and external balance in Sasang Constitutional Medicine instead of reinforcing and reducting method of Neiging Medicine. 6. The Yin-Yang of Korean Traditional Medicine developed centering on the human from centering on the nature and Sasang Constitutional Medicine was a practical medicine compared with Neiging Medicine.