• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.433-436
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• 2011

The effect of plasma on flow characteristics in subsonic flow in backward-facing step is studied. The velocty of main flows are 0.5 m/s. DBD plasma is using for flow control. Stainless foil and polymide films are used as an electrode and dielectric material. The change of flow characteristics are shown by different of plasma generation region in fluid flow.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.6
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• pp.33-41
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• 2015

Scaled model of a dual-mode ramjet engine with large backward-facing step, as a component of the rocket-based combined cycle engine, was designed. Design parameters were derived for this engine with the consideration of application for the rocket-based combined cycle engine. Design methodology was established for these design parameters. The design was partially verified through numerical study. Flow characteristics of the dual-mode ramjet engine with large backward-facing step was investigated experimentally. The design methodology for relevant design parameters established in this study was verified as feasible.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1317-1325
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• 2015

There are two types of clinical research to figure out risk factor for disease using collected data. One is prospective study to approach the subjects from the present time and the other is retrospective study to find the risk factor using the subject's information in the past. Both approached and study design are different but the purpose of the two studies is to identify a significant difference between two groups and to find out what the variables to influence groups. Especially when comparing the two groups in clinical research, we have to look at the difference between the impact clinical variables by group while controlling the influence of the baseline characteristics variables such as age and sex. However, in the retrospective study, the difference of baseline characteristic variables can occur more frequently because the past records did not randomly assign subjects into two groups. In clinical data analysis use covariates to solve this problem. Typically, the analysis method using the analysis of covariance of variance, adjusted model, and propensity score matching method. This study is introduce the way of equality adjustment between groups data analysis using covariates in retrospective clinical studies and apply it to the recurrence of gastric cancer data.

• 월간산업보건
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• s.46
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• pp.16-20
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• 1992

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.97-103
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• 2003

Numerical research has been done for the transverse jet behind a rearward-facings step in turbulent supersonic flow without chemical reaction. Purpose of transverse jet is to enhance mixing of the fuel in the combustor. Two-dimensional unsteady flowfields generated by slot injection into supersonic flow are numerically simulated with the Navier-Stokes equations with two-equation k-$\varepsilon$ turbulence model. Numerical method is used high-order upwind TVD scheme. Eight cases are computed for different slot momentum flux ratios and slot position at downstream of the step. The flow is very similar to the cavity flow, because the jet acts as an obstacle. The numerical results thus show the periodic phenomenon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.507-514
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• 2009

Large eddy simulation code was developed to predict the turbulent flows over backward-facing steps including a recirculating flow phenomena. Localized dynamic ksgs-equation model was employed as a LES subgrid model and the LES solver was implemented on parallel computer consisting of 16 processors to reduce computational costs. The results of laminar flow showed qualitative and quantitative agreements between current simulations and experimental results availablein literatures. The simulation of the turbulent flows also yielded reasonable results. From these results, it can be expected that developed LES code will be very useful to analyze the combustion in stabilities and noise of a practical combustor in the future.

• Journal of Korean Academy of Nursing Administration
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• v.8 no.3
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• pp.403-410
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• 2002

최근 병원행정가들의 가장 관심을 끄는 분야 중 하나가 간호사의 이직이다. 본 연구는 실제 이직을 한 간호사를 대상으로 이직요인을 파악하고 이에 대한 이직대책을 제시함으로써 조기에 간호사의 이직을 예방하여 효율적으로 간호인력을 관리하고 간호의 질적 향상을 하는데 도움을 주고자 46개 종합병원에서 1998년 1월${\sim}$1999년 1월 사이에 이직을 한 간호사 369명을 대상으로 조사, 분석한 후향연구이다. 연구결과를 통해 이직결정에는 다양한 요인들이 영향을 미침을 알 수 있었다. 특히 결혼상태가 가장 큰 요인으로 나타났으며, 기혼인 경우는 자식의 양육문제가 가장 원인이었으며, 미혼인 경우는 불규칙한 근무시간이 큰 영향을 미치고 있었다. 그에 대한 해결책으로 자식 양육문제의 경우, 근무병원 내에 탁아시설을 운영하거나 육아양육휴가제도 및 시간제 근무 등의 도입을 심각하게 고려해 볼 필요가 있다. 불규칙한 근무시간은 근무외 수당을 지불하거나 간호사가 스스로 자신의 근무시간을 선택할 수 있는 융통성 있는 스케줄링, 또는 승진평가 제도를 적절하게 할 수 있는 제도의 도입을 제안한다.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.37-47
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• 2003

• 월간산업보건
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• s.79
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• pp.34-35
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• 1994

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.109-109
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• 2009