• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2169-2177
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• 2010

The effects of job related factors on psychosocial health status were examined by taking job stress into account. The self-administered questionnaires were performed, during the period between Oct. 1st, 2009 and Nov. 30th, 2009, to 805 individuals in the service of general administration located in Daejeon City. Causal relationships between job related factors, job stress, and, psychosocial health status were examined by structural equation model. The main finding as follows: For correlations of such indices of psychosocial health status as PWI and MFS with various studied items, all of these two indices were found to be in a negative correlation with the job position, job career, satisfaction in job life, autonomy of job, supervisors support and coworkers support, whereas in positive correlation with the experience of sick absence per year and job demand. With the analysis of structural equation model, the degree of job stress factors was more influential on the level of psychosocial health status than job related factors in such a manner as that the greater the job stress, while the lower the job related factors, the higher the psychosocial health status(PWI and MFS). Moreover, it was found to have the inter-relational effects that the greater the job related factors, the lower the job stress factors. Thus the effective strategy for stress and fatigue symptoms reduction among governmental employees requires additional programs focusing on innovated job specifications.

• Journal of Energy Engineering
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• v.21 no.3
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• pp.254-264
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• 2012

Rayleigh-Benard natural convection experiments were carried out as the preliminary experiment to simulate the natural convection of the core melt at the severe accident conditions. This work focused on the influences of plate separation distance(s), the existence of the side walls and crust geometries of upper and lower plates. Based upon the analogy concept, a cupric acid-copper sulfate electroplating system($H_2SO_4-CuSO_4$) was employed as the mass transfer system and measurements were made for $Ra_s$ ranging from $1.06{\times}10^7$ to $2.91{\times}10^{10}$. The test results measured for a single horizontal plate were in good agreement with the correlation reported by McAdams and those for two horizontal plates showed the similar trend to the existing Rayleigh-Benard heat transfer correlations developed by Dropkin and Somerscales, Globe and Dropkin. The measured heat transfer rate decreased with the increasing separation distance between the two plates and became similar to those for a single horizontal plate. Fin arrays mounted on both upper and lower plates enhanced the heat transfer rates. For all cases, the heat transfer rates measured for open side walls are higher than those for closed ones.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.45-62
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• 2010

Zero plane displacement (d) is the elevated height of the apparent momentum sink exerted by the vegetation on the air. For a vegetative canopy, d depends on the roughness structure of a plant canopy such as leaf area index, canopy height and canopy density, and thus is critical for the analysis of canopy turbulence and the calculation of surface scalar fluxes. In this research note, we estimated d at the Gwangneung coniferous forest by employing two independent methods of Rotach (1994) and Martano (2000), which require only a single-level eddy-covariance measurement. In general, these two methods provided comparable estimates of $d/h_c$ (where $h_c$ is the canopy height, i.e., ~23m), which ranged from 0.51 to 0.97 depending on wind directions. These estimates of $d/h_c$ were within the ranges (i.e., 0.64~0.94) reported from other forests in the literature but were sensitive to the forms of the nondimensional functions for atmospheric stability. Our finding indicates that one should be careful in interepreation of zero plane displacement estimated from a single-level eddy covariance measurement that is conductaed within the roughness sublayer.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.97-103
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• 2015

Natural convection heat transfer rates in vertical pipes were measured varying the diameter, length, and roughness of vertical cylinder. To achieve high Rayleigh number with relatively small test rig, mass transfer experiments instead of heat transfer were performed based on the analogy. Prandtl number was 2,014. The length of vertical cylinder was 0.1m, 0.3m, and 0.5m, which correspond to GrL $4.2{\times}10^7$, $1.1{\times}10^9$, and $5.5{\times}10^9$. To each length of vertical cylinder, the heat transfer rates were measured varying the iameter 0.005m, 0.01m, and 0.03m. The heat transfer rate for a short length pipe(0.1m) agreed with the prediction from Le Fevre correlation developed for a vertical plate for all diameter. The heat transfer rate decreases as the diameter and the length of the pipe increases. The heat transfer rate inside of vertical cylinder is affected by roughness only for a laminar flow regime.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.930-938
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• 2018

Underwater noise radiated from submarines is directly related to the probability of being detected by the sonar of an enemy vessel. Therefore, minimizing the noise of a submarine is essential for improving survival outcomes. For modern submarines, as the speed and size of a submarine increase and noise reduction technology is developed, interest in flow noise around the hull has been increasing. In this study, a noise analysis technique was developed to predict flow noise generated around a submarine shape considering the free surface effect. When a submarine is operated near a free surface, turbulence-induced noise due to the turbulence of the flow and bubble noise from breaking waves arise. First, to analyze the flow around a submarine, VOF-based incompressible two-phase flow analysis was performed to derive flow field data and the shape of the free surface around the submarine. Turbulence-induced noise was analyzed by applying permeable FW-H, which is an acoustic analogy technique. Bubble noise was derived through a noise model for breaking waves based on the turbulent kinetic energy distribution results obtained from the CFD results. The analysis method developed was verified by comparison with experimental results for a submarine model measured in a Large Cavitation Tunnel (LCT).

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.383-392
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• 2013

In order to promote social responsibility, a company reads to engage in various activities to increase their competitiveness to ensure stable and continuous development. One of the activities is to input human/material resources in order to draw and develop the core abilities of member for the productivity improvement of the company. This study is concerned with capability improvement of members in relation to core company performance, the focus of the study is to identify how education training in a company may contribute to team performance by leaning transfer through empirical study. As a result of this study, it was found that the personality of members, as well as the training programs, within the company can be a significant factor for improving productivity and performance of the company. In addition, team members noted that learning transfer take place when effectively lead through the leadership of a boss and identified that this leadership ultimately has a significant effect on team performance.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.61-68
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• 1996

In this paper we propose a new visualization technique to characterize qualitative information of a large DNA sequence. While a long DNA sequence has huge information, it is not easy to obtain genetic information from the DNA sequence. We transform DNA sequences into a polygon to compute their homology in image domain rather than text domain. Our program visualizes DNA sequences with colored random walk plots and simplify them k-convex hulls. A random walk plot represents DNA sequence as a curve in a plane. A k-convex hull simplifies a random work plot by removing some parts of its insignificant information. This technique gives a biologist an insight to detect and classify DNA sequences with easy. Experiments with real genome data proves our approach gives a good visual forms for long DNA sequences for homology analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.6
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• pp.98-104
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• 2015

Excessive thrust acting on the rotor of pump can cause the damage of pump or the decrease of pump lifetime. Therefore, for ensuring the safety of LOX pump of a liquid rocket engine, the thrust of pump rotor is estimated by similarity tests. Axial thrust is indirectly measured by an axial thrust measurement unit positioned outside pump. Radial thrust is calculated based on pressure distribution of volute scroll. As a result, axial and radial thrust are increased when the flowrate of pump decreases. However, both thrusts do not affect the stability of pump rotor since their values are not large.

• Journal of the KSME
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• v.33 no.1
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• pp.22-32
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• 1993

본드선도는 물리적 등가가 적용되는 모든 상사 시스템을 대단히 조직이며 일관성 있게 모델링할 수있을 뿐만 아니라 시스템의 동적 방정식을 제어동역학 관점에 유리한 상태방정식으로 직접 유도할 수 있다. 또한 본드선도는 모델링 단계에서 무시된 각 요소들의 동적 특성 즉, 기계시스 템에서 회전축의 탄성처짐이나 운동 물체들 사이의 마찰 효과 전기 . 자기시스템에서 자속유출량, 그리고 유체 . 유압시스템에서 밀봉부분의 유량손실이나 압축성 유체 특성 등을 기곤에 구성된 본드선도의 변경 없이 각 특성들이 나타나는 본드상에 적절한 접합요소와 함께 단순히 첨가하여 고려할 수 있기 때문에 모델링 과정을 다시 반복하지 않고도 무시된 동적 특성들이 전체시스템에 미치는 영향을 파악할 수 있다. 특히 본드선도가 에너지 변환 장치나 에너지 유동 메카니즘이 복잡한 다에너지역 시스템 등에 거동이 전체시스템에 미치는 효과를 시각적으로 보다 세밀히 파악할 수 있을 뿐만 아니라 구성된 본드선도에 인과관계를 할당하여 본드선도의 접합요소를 통하여 유도된 최종적인 동적 방정식이 현실적으로 실현 가능한 물리시스템인지 파악할 수 있어 본드선도 모델링 단계에서 시스템을 묘사하는 동적 방정식의 옳고 그름을 평가할 수 있다. 이와 같이 본드선도는 기계, 전기 . 자기, 유체 . 유압, 열 시스템 및 이들이 조합된 복잡한 다에너지역 시스템 등을 효과적으로 모데링할 수 있는 매우 유용한 동적 시스템 모델링 방법이다.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.837-840
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• 2010

본 연구는 급변하는 의료환경에 대비하여 간호의 질 향상 및 증진을 통한 환자 만족도 증진을 위해 간호전달체계를 기능적 간호방법에서 팀간호제 방법으로 전환을 하면서 이에 따른 간호활동 및 직무 만족도를 조사하였다. 간접간호 수행률 조사를 살펴보면 기록간호, 확인업무, 물품관리, 간접소통, 전달 업무 등 모두에서 유의한 차이를 보이지 않았다. 영양간호, 전적인 식사보조 등은 간호직무만족도가 영향을 미치는 것으로 나타났다. 간호사 직무만족도는 어려움이 있을 때 동료나 상사에게 의논하는 것으로 나타났다. 안전간호, 화재예방 등이 영향을 미치는 것으로 나타났다. 간호사 업무성과 병동의 시설과 기구를 적절히 관리한다. 간호사 업무성과, 환자에게 적절한 휴식 및 안정을 위한 간호를 제공하는 것으로 나타났다. 본 연구 결과 간호사들이 역할을 명확히 규명하고 세분화하여 이를 수행하는 직무내용을 명확하게 파악하고 작업표준 지침서를 작성하여 활용한다면 간호사들의 자가 관리 증진은 물론 환자와 보호자에게도 만족감을 높여 줄 수 있는 계기가 될 것이며, 이를 통한 다양한 팀제 운영이 될 것이라 생각된다. 또한, 향후 다양한 업무 개선 활동이 가능할 것이라 생각된다.