• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 한국재료학회 춘계학술발표강연 및 논문개요집
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• pp.94-94
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• 1998

• 정보관리학회지
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• 제28권3호
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• pp.103-121
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• 2011

본 연구는 RDA 자원유형을 KCR4에 적용하기 위한 방안을 모색하기 위한 것이다. KCR4의 GMD는 내용과 용기의 용어가 혼합되어 적합한 용어를 선정하기 어렵고, FRBR 개념모형 구현도 용이하지 않다. SMD도 이용자의 요구에 맞는 최신의 용어가 포함되지 않아 변경이 필요한 실정이다. 기 개발된 RDA 자원유형은 AACR2 GMD의 한계를 극복하기 위해 다양한 용어의 측면을 고려하였고, 앞으로 목록분야에 많은 영향을 줄 수 있다. 따라서 국내 목록환경에 RDA 자원유형의 적용가능성이 모색되어야 할 것이다. 이를 위해 사례조사, 설문조사를 실시하였으며, 사례조사는 국내 대학도서관 한 개 기관을 대상으로 GMD 기술의 전수조사를 실시하여 용어의 변경 및 사서 및 이용자가 원하는 용어의 방향을 파악하였다. 설문조사에서는 국내 대학도서관 사서를 대상으로 자원유형 기술의 현황과 문제점 및 RDA 자원유형 이해정도를 파악하였다. 조사결과 자원유형 용어는 검색과 기술을 위해 구체적이고 이용자가 이해하기 쉬운 용어로 변경이 필요하였다. RDA 적용 테스트에서는 자원유형에 따라 정답률에 차이가 있었다. 조사를 바탕으로 RDA 내용유형에 컴퓨터게임을, 용기유형에 DVD, CD-ROM, Blu-Ray, 컴퓨터파일을 추가하여 KCR4의 자원유형을 제안하였다. 기술방식과 화면출력에서도 RDA의 방식을 제안하였다. 본 연구는 RDA 자원유형의 국내 적용가능성을 모색하여, KCR4 자원유형 개정의 기반을 마련하였다.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.17-24
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• 2006

This study was performed to figure out spray behavior and fuel atomization characteristics of a piezo-driven injector and a solenoid-driven injector in the common-rail injection system under the same design parameters and test conditions. The process of spray injection was visualized by using the spray visualization system composed of a Nd:YAG laser and an ICCD camera. The atomization characteristics were investigated in terms of axial mean velocity, Sauter mean diameter(SMD) and droplet distributions obtained from a phase Doppler particle analyzer system. Compared with solenoid-driven injector, the piezo-driven injector has short injection delay and reaches quickly to the maximum injection value. Spray tip penetration shows some difference, however, spray angle of piezo-driven injector is wider than that of solenoid-driven injector. Sauter mean diameter of piezo-driven type injector is smaller than that of solenoid-driven type.

• Journal of Mechanical Science and Technology
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• 제18권7호
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• pp.1187-1195
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• 2004

The objective of this study is to investigate the effects of fuel temperature on the spray characteristics of a dual-orifice type swirl injector used in a gas turbine. The major parameters affecting spray characteristics are fuel temperature and injection pressure entering into the injector. In this study, the spray characteristics of a dual-orifice type swirl injector are investigated by varying fuel temperature from - 30$^{\circ}C$ to 120$^{\circ}C$ and injection pressure from 0.29 to 0.69 ㎫. Two kinds of fuel having different surface tension and viscosity are chosen as atomizing fluids. As a result, injection instability occurs in the low fuel temperature range due to icing phenomenon and fuel property change with a decrease of fuel temperature. As the injection pressure increases, the range of kinematic viscosity for stable atomization becomes wider. The properties controlling the SMD of spray is substantially different according to the fuel temperature range.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.54-61
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• 2001

It is reported that during the cold starting, especially in gasoline engine, the engine response and the effect of HC emission can be improved by prompting atomization and reducing the quantity of fuel adhered to the range of injector tip, inlet port, and inlet valve. The purposes of this study are to promote atomization of fuel before air-fuel mixture in the inlet port. In order to achieve its goal, the glow plug is to evaluate the feasibility of for the early fuel evaporator and the spray behavior characteristics of gasoline, injected on the surface of glow plug with room temperature(2$0^{\circ}C$) and high temperature(25$0^{\circ}C$) is to examine. Particle motion analysis system(PMAS) was used to measure the SMD and the dropsize distribution of impinging spray and free spray. The results of this experiment, evaporation rate of impinging spray was higher than that of free spray, and the higher evaporation rate win, the smaller peak dropsize was. Especially, during early spray SMD of impinging spray was still smaller than that of fee spray.

• 성인간호학회지
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• 제29권2호
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• pp.177-189
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• 2017

Purpose: A meta-analysis was conducted to identify the effect of cognitive improvement programs for the elderly with mild cognitive impairment (MCI) in Korea. Methods: Five databases, as well as relevant reference lists, of studies published from 2000 to 2016, were searched. Fourteen studies were identified. Quality assessments of included studies were conducted using the Scottish Intercollegiate Guidelines Network checklist. An R program was used to analyze effect sizes and to identify possible sources of heterogeneity among studies. The potential for publication bias was investigated using a funnel plot, Egger's regression test and sensitivity analysis. Results: The total effect size was large (Standardized Mean Difference [SMD]=1.44, 95% CI: 1.11~1.77), with cognition based intervention (SMD= 1.77, 95% CI: 1.26~2.29) and exercise intervention (SMD=1.13, 95% CI: 0.82~1.44). Statistically significant moderators were identified intervention type by meta-ANOVA analyses. Finally, no significant evidence of publication bias was found. Conclusion: There is clear evidence that cognitive improvement programs can greatly enhance cognition in elderly with MCI. Future research should examine the effects of non-pharmacological interventions targeting elderly populations with mild-to-severe cognitive impairment in order to develop and enhance the effectiveness of cognitive improvement programs in Korea.

• 한국의류학회지
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• 제26권2호
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• pp.355-363
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• 2002

The purpose of this study was to investigate how the weave type, yarn twist fabric count and fiber content of the worsted fabrics affect the subjective sensation of the hand. Thirty worsted fabrics that were mainly used for the spring and fall ladies'suits at national brands were selected. Variables were such as four different kinds of weave types, plain, twill, satin and decorative; two levels of yarn twist, normal and high; various fabric counts; two different fiber contents, pure wool and Lycra contained. Image analysis and wavelet transform techniques were used to quantify the surface fiber, For surface characteristics, MIU, MMD and SMD were measured by KES-FB system. The Questionnaires with 23 adjectives were used for the subjective hand evaluation. Panels were So specialists of fashion or fabric designers and merchandizers. By Factor Analysis, six factors that represent the subjective hand were extracted. The relationship between these factors and structural variables were analyzed. Yarn twist was significantly related to the surface characteristics and resilience. Weave structure affected surface characteristics, volume/warm-cool feeling and resilience. Fabric counts showed relations with volume/warm-cool feeling and the fiber contents with volume/warm-cool feeling, resilience and elastic properties. MIU, MMD and SMD showed no relations with the surface fibers. Subjective sensation of surface characteristics was affected by SMD and surface fibers.

• 전자공학회논문지SC
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• 제43권4호
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• pp.45-52
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• 2006

본 연구에서는 위상잡음과 지터(jitter) 특성을 개선한 $5mm{\times}7mm$ 크기의 적층 세라믹 SMD(surface mounted device)형 VCXO를 개발한다. PECL(positive emitter coupled logic) 칩패키지를 발진수정자에 결선한 VCXO는 그 길이 및 패키지 내부의 패턴 등에 의하여 부유인덕턴스 및 기생 커패시턴스가 발생하고, 전원의 반사 및 잡음 발생으로 출력신호의 진폭 감소 및 신호 손실이 발생하여 발진기 성능을 정상적으로 평가할 수 없다. 이러한 신호 손실 및 진폭감소를 방지하기 위해 지그(Jig) 시스템을 개발하고, 이를 통하여 발진기의 정확한 스펙트럼 분석 및 성능을 평가한다. 동작전원은 3.3 V, 주파수 범위 120-180 MHz 및 Q인수는 5K이다.

• 한국추진공학회지
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• 제13권6호
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• pp.41-47
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• 2009

작동 유체에 따른 APU 가스터빈에 적용되는 연료노즐의 분무특성을 확인하였다. 액체연료에 따라 점도, 표면장력 및 비중 등이 상이하여 분무특성이 변화될 수 있다. 본 연구에서는 연료 물성치 변화에 따른 분무특성을 이해하기 위하여 케로신과 유사한 특성을 갖는 보정 유체 2와 일반적으로 연료노즐의 분무특성을 시험하는데 사용하는 물을 이용하여 분무 시험을 수행하였다. 분무가시화와 분무입자 크기 및 분포를 ND-Yag 레이저 및 PDPA(Phase Doppler Particle Analyzer)를 이용하여 측정하였다. 분무시험 결과, 두 작동유체의 분무형태는 유사하게 나타났으며 주 분무영역에서의 SMD 또한 유사하게 분포됨을 확인할 수 있었다.

• 한국통신학회논문지
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• 제30권2A호
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• pp.107-113
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• 2005

본 논문에서는 통신소자의 경박 단소화 추세에 따라 적층 세라믹 SMD(surface mounted device) 패키지기술을 통하여 소형화한 $5{\times}7mm$의 크기의 VCXO를 개발한다. 이때 안정된 입력신호를 공급하기 위하여 양의 이미터결합논리(PECL)를 이용하고, 역메사형 HFF(high frequency fundamental) 기법을 이용하여 제작한 수정소자로 IC에 설계함으로써 동작전압은 3.3 V, 저전력하에서 120MHz-180MHz 범위의 주파수에서 발진하며, Q인자는 5 K이상, 3.5 ps rms의 낮은 지터(Jitter)와 위상잡음 특성 및 일정기간의 경화실험에서도 안정된 출력특성을 보인다.