• 한국화재소방학회논문지
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• 제15권2호
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• pp.91-95
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• 2001

복도나 터널과 같이 특정한 방향성을 가지는 공간에서는 천장아래에 형성되는 연기선단의 성상해석이 학술적인 면에서나 실용적인 면에서도 매우 중요하다. 본 연구는 2차원 축대칭 천장제트 선단의 전파속도를 모델화하기 위하여 상사해석 및 차원해석을 수행하였다. 실험에서는 질소와 헬륨의 혼합가스를 원형 천장에 노즐로 분출시켜 화재로 인한 연기를 구현하였으며 속도측정을 위하여 레이저와 고속카메라를 이용한 가시화 기법이 사용되었다.

• 한국소음진동공학회논문집
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• 제25권2호
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• pp.75-82
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• 2015

Noises from the large scale marine propeller are calculated numerically on non-cavitation condition. The hydrodynamic analysis is carried out by potential based panel method with time marching free wake approach. The distribution of hydrodynamic loads on the propeller surface and noise signals are obtained using the unsteady Bernoulli's equation and the Farasssat's formula respectively. It turns out that the noise signal at the narrow band shows strong peak at the blade passage frequency, and the peak value at the 1/3 octave band also shows the same trend. Noise signals and directivity patterns for both the thickness and the loading noise are compared with each other. The directivity pattern for the loading noise shows minor lobe at the backward side of the rotating disc plane.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.592-596
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• 2007

본 연구에서는 구조물 전면에서 발생하는 권파와 그 이후 발생하는 처오름과 월파의 유속장을 계측하기 위하여 수리모형실험을 실시하였으며, 실험결과를 이용하여 월파의 유속분포를 나타내는 경험식을 제안하였다. 구조물 전면에서 내습파랑이 쇄파된 이후, 구조물을 월파하는 동안에 유체의 흐름은 넓은 연행기포의 지역을 형성하며 다위상(multiphase)상태가 된다. 쇄파에 의한 구조물 주위에서의 유체흐름 중 연행기포가 없는 영역의 유속 측정에는 입자화상유속계(particle image velocimetry, PIV)기법을, 연행기포 영역에서의 유속 측정에는 기포화상유속계(particle image velocimetry, BIV)기법을 적용하였다. 두 기법을 이용하여 측정된 유속장으로부터 구조물 주위에서의 쇄파, 처오름 및 월파시의 최대유속을 계측하였다. 구조물 위로 월파된 유체 흐름 분포는 비선형적인 특성을 보여주며, 시간별 최대유속은 주로 유체의 전면부에서 발생하는 것으로 나타났다. 또한 무차원화된 유속분포로부터 구조물 위에서의 월파시 유속분포가 자기상사성(self-similarity)을 갖는다는 것을 알 수 있었으며, 이를 이용하여 월파의 유속분포를 위한 실험적 경험식을 제시하였다.

• 한국콘텐츠학회논문지
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• 제8권8호
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• pp.223-234
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• 2008

본 연구의 목적은 외식산업을 중심으로 한 서비스산업 종사원의 인식된 사회적 교환관계와 조직시민행동 간의 영향관계를 파악하여 서비스산업의 인적자원관리의 효율성을 제고하는데 있으며, 이러한 연구목적을 달성하기 위하여 문헌적 연구와 구조모형분석을 이용한 실증적 연구를 함께 실시하였다. 본 연구에서 사회적 교환관계는 인식된 상사지원, 인식된 동료지원, 인식된 조직지원으로 구성하였고, 조직시민행동은 개인에 대한 조직시민행동과 조직에 대한 조직시민행동으로 구성하여 각 변수들 간의 영향관계를 파악하였으며, 이러한 분석결과를 바탕으로 서비스산업의 인적자원관리 방안을 제시하였다.

• 설비공학논문집
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• 제18권2호
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• pp.129-136
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• 2006

Optimal design of an air-to-liquid finned plate heat exchanger is considered theoretically in this study. Based on existing correlations for the pressure loss and the heat transfer in channel flows, the optimal configuration of the plate heat exchanger including the optimal plate pitch and the optimal fin pitch is obtained to maximize the heat transfer within the limit of the pressure drop for a given flow depth of the plate heat exchanger. It is found that the optimal fin pitch is about one ninth of the optimal plate pitch. In the optimal configuration, the flow and thermal condition in the channels is just at the boundary between the laminar developing and laminar fully developed states. It is also found when reducing the flow depth of plate heat exchangers for compactness, the heat transfer performance can be maintained exactly the same if the geometric parameters such as the plate thickness, plate pitch, fin thickness, and fin pitch are reduced proportional to the square root of the flow depth as long as the flow keeps laminar within the heat exchangers.

• 대한간호학회지
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• 제46권6호
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• pp.824-835
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• 2016

Purpose: The purpose of this study was to analyze the paths of influence that a hospital's ethical climate exerts on nurses' organizational commitment and organizational citizenship behavior, with supervisor trust as the mediating factor, and verify compatibility of the models in hospital nurses. Methods: The sample consisted of 374 nurses recruited from four hospitals in 3 cities in Korea. The measurements included the Ethical Climate Questionnaire, Supervisor Trust Questionnaire, Organizational Commitment Questionnaire and Organizational Citizenship Behavior Questionnaire. Ethical Climate Questionnaire consisted of 6 factors; benevolence, personal morality, company rules and procedures, laws and professional codes, self-interest and efficiency. Data were analysed using SPSS version 18.0 and AMOS version 18.0. Results: Supervisor trust was explained by benevolence and self-interest (29.8%). Organizational commitment was explained by benevolence, supervisor trust, personal morality, and rules and procedures (40.4%). Organizational citizenship behavior was explained by supervisor trust, laws and codes, and benevolence (21.8%). Conclusion: Findings indicate that managers need to develop a positive hospital ethical climate in order to improve nurses' trust in supervisors, organizational commitment and organizational citizenship behavior.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.208-215
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• 2001

An experimental method to investigate the dynamic charasteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly met with capability of test facilities. It is suggested that the linear wave component that is unable to satisy similarity is separated with others. The model experiment can be carried out with mitigated condition for the linear wave components while others including wave drift, current and wind are keeping the similarities. Then the result is extrapolated to give the dynamic behavior of buoys in extreme condition because linear wave component is soley responsible to oscillatory buoy motion and other environmental components are applied as a initial tension. the similarity for current and wind conditions is viewed as equivalence of restoring forces. the validity of proposed method is examined with different types of standard ocean buoys and it indicates that the linearity of measured characteristics is assured with a limitation of resonable distance between test and estimated wave conditions.

• 산학경영연구
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• 제13권
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• pp.31-47
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• 2000

지금까지 신뢰는 연구 목적과 분야에 따라 여러 각도에서 조망되어 봤다. 본 연구에서는 조직 행동적 차원에서의 신뢰에 대한 기존 연구들을 살펴보는 한편, 최근 제안되고 있는 신뢰 형성 모형의 타당성을 한국적 조직 현실 속에서 실증코자 시도하였다. 신뢰 개념에 대한 여러 시각과 연구 경향을 간략히 소개하였으며, 특히 실증 연구를 통해 신뢰 형성의 4가지 선행 요인으로 제안되어 온 능력, 선의, 신실성 및 개인 신뢰성향의 실재성를 검토하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.567-570
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• 2003

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been developed the new approach method to express the Fractal Dimension(FD) for aging level calculation and estimation system of outside insulator using special image processing algorithm. As a result after FD testing, the recognized aging estimation of FD has a very characteristics compared to the conventional visual inspection.

• Journal of Biosystems Engineering
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• 제14권3호
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• pp.158-167
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• 1989

This study was conducted to investigate the applicability of true model theory in a powered lugged wheel-soil system and to examine the possibility of using principles of similitude in investigating the dimensions of soil parameters pertinent to a powered lugged wheel-soil system concerning the sinkage prediction. The following conclusions were derived from the study; 1) The sinkage of prototype wheels proved to be predicted by those of the model wheels for the range of the dynamic weight tested. 2) A conditional equation which can be used for the prediction of sinkage of prototype by model test was derived as $n_f=n{_\ell}{^{-b}}$. The range of the numerical value of b, which is the exponent on the length dimension of the soil property ${\alpha}$, was found to be -1.48~-2.54. 3) Considering a relatively wide variation of b values, it was concluded that there are several soil properties which are pertinent to the powered lugged-wheel soil system concerning the sinkage prediction.