• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.174-180
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• 2002

A virtual reality technology for multipurpose numerical simulation is developed to reproduce and investigate a variety of ocean environmental problems in a 3D-Numerical Wave Tank. The governing equations for solving incompressible fluid motion are Navier-Stokes equation and continuity equation, and the Marker-Density function technique is adopted to implement the fully-nonlinear free-surface kinematic condition. The marine environmental situations, i.e. waves, currents, wind, etc., are reproduced by use of multi-segmented wavemaker on the basis of the so-called "snake-principle". In this paper, some numerical reproduction techniques for regular and irregular waves, multi-directional waves, Bull's-eye wave, wave-current, and solitary wave are presented, and a model test in motion with large amplitude of roll angle is conducted in the developed 3D-NWT, using a overlaid grid system.

• 한국도서관정보학회지
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• 제53권4호
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• pp.71-100
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• 2022

본 연구는 2021년도 경기도 유아 책꾸러미 정기배송 사업의 성과를 도출하고, 사업의 문제점을 분석하여 개선방안을 제시하여 경기도 독서문화진흥 정책 마련에 도움을 주고자 함에 그 목적이 있다. 이 사업의 성과 분석 및 개선방안 제시를 위해 양육자와 독서코칭사를 대상으로 만족도 조사를 실시하였으며, 전문가 의견수렴과 사업주관자 및 수행사업자를 대상으로 자체 사업 평가를 실시하였다. 만족도 조사 결과 사업의 필요성 및 만족도는 양육자 및 독서코칭사 모두 매우 높게 나타났으며 특히 양육자의 경우 사업 후 독서량이 많이 증가할수록 본 사업의 필요성과 만족도가 더 높은 것으로 나타났고 사업이 중단될 경우에도 지속적으로 책꾸러미 정기배송과 같은 프로그램에 참여하고 싶어하는 것으로 나타났다. 전문가 의견 수렴에서도 양육자의 독서육아에 대한 긍정적인 인식 변화가 있으며, 유아-부모 상호작용 발달로 이 사업의 필요성과 만족도가 매우 높다는 평가를 하였다. 다만 사업주관 및 수행기관의 자체 평가에서는 사전에 철저한 계획적인 준비를 통해 사업이 진행되어야 더 좋은 성과를 낼 수 있을 것으로 평가하였다. 이를 통해 경기도 유아 책꾸러미 정기배송 사업의 지속성을 위해 그 개선방안을 제시하고 경기도 독서문화진흥 정책을 제안하였다.

• 한국인구학
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• 제35권2호
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• pp.159-184
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• 2012

본 연구는 노동시장 통합이 결혼 이행에 미치는 영향을 분석한다. 결혼 시점과 결혼 3년 전의 일자리 유무와 고용형태를 가지고 일자리의 안정성과 지속성이 초혼 형성에 유의한 영향을 미치는지 살펴보았다. 특히 1997년 외환위기 이전과 이후에 노동시장에 진입했을 가능성이 높은 두 집단을 코호트별로 나누어, 거시적인 사회경제적 변동 과정에서 노동시장통합이 결혼에 미친 차별적 영향에 대해 분석한다. 한국노동패널을 사용하여 2008년도 기준으로 18세 이상인 성인 남녀의 결혼 이행을 분석한다. 분석 결과, 취업상태와 정규직 근무는 남성의 초혼 형성 해저드는 높이는 반면 여성의 초혼 형성 해저드는 낮추었다. 장기무직, 즉 교육이나 군대 기간을 제외하고 결혼 전 3년 동안 2년 이상 무직 상태에 있을 때 남녀 모두 결혼이 지연될 가능성이 높았다. 정규직 근속기간이 2년 이상인 여성은 그렇지 않은 여성보다 결혼 해저드가 높아졌다. 정규직 근속기간이 긴 남성에게서는 이러한 효과가 나타나지 않았다. 또한 코호트별로 통계적으로 유의한 차이가 발견되어 최근의 사회경제적 불확실성과 노동시장 불안정화의 부정적 영향이 더욱 강화되었음을 시사했다.

• 농업과학연구
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• 제37권1호
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• pp.37-43
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• 2010

This study carried out to develop barrier-free certification program in forest trail. It is done to provide the certification system presented about certification organized, certification standard and indexes, evaluation method and operation plan. In order to develop certification program in forest trail, detailed measurement index must be developed earlier based on an accessbility, a stability, a preservation and a walking continuity. The suitable forest trail for weak pedestrian was investigated that running slope should be 1/20(5%) maximum, cross slope cannot exceed 1/50(2%) maximum and clear tread width should be above of minimum 90cm. In addition, the trail type is designed as a mixed trail system which is a combination of the loop and the line form and its distance should be 225~675m. Finally, forest trail should be manage sustainably by having regular monitoring and evaluation.

• 한국지구과학회지
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• 제36권5호
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• pp.476-483
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• 2015

The high-order Laplacian-type filter, which is capable of providing isotropic and sharp cut-off filtering on the spherical domain, is essential in processing geophysical data. In this study, a spherical high-order filter was designed by combining the Fourier method with finite difference-method in the longitude and latitude, respectively. The regular grid system was employed in the filter, which has uniform angular spacing including the poles. The singularity at poles was eliminated by incorporating variable transforms and continuity-matching boundary conditions across poles. The high-order filter was assessed using the Rossby-Haurwitz wave, the observed geopotential, and observed wind field. The performance of the filter was found comparable to the filter based on the Galerkin procedure. The filter, employing the finite difference method, can be designed to give any target order of accuracy, which is an important advantage being unavailable in other methods. The computational complexity is represented with 2n-1 diagonal matrices solver with n being the target order of accuracy. Along with the availability of arbitrary target-order, it is also advantageous that the filter can adopt the reduced grid to increase computational efficiency.

• Journal of mucopolysaccharidosis and rare diseases
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• 제1권2호
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• pp.35-39
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• 2015

Sleep problems occur frequently among patients with Prader-Willi syndrome (PWS). The most common problem is excessive daytime sleepiness (EDS) that are closely related to of sleep-related breathing disorder (SRBD) such as obstructive sleep apnea (OSA) and congenital hypoventilation syndrome. Obesity, craniofacial dysmorphism and muscular hypotonia of patients with PWS may increase the risk of SRBD. Sleep apneas can interrupt the continuity of sleep, and these disruptions result in a decrease in both the quality and quantity of sleep. In addition to SRBD, other sleep disorders have been reported, such as hypersomnia, a primary abnormality of the rapid eye movement (REM) sleep and narcolepsy traits at sleep onset REM sleep. Patients with PWS have intrinsic abnormalities of sleep-wake cycles due to hypothalamic dysfunction. The treatment of EDS and other sleep disorders in PWS are similar to standard treatments. Correction of sleep hygiene such as sufficient amount of sleep, maintenance of regular sleep-wake rhythm, and planned naps are important. After comprehensive evaluation of sleep disturbances, CPAP or surgery should be recommended for treatment of SRBD. Remaining EDS or narcolepsy-like syndrome are controlled by stimulant medication. Bright light therapy might be beneficial for disturbed circadian sleep-wake rhythm caused by hypothalamic dysfunction.

• 의학교육논단
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• 제13권2호
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• pp.59-68
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• 2011

This study investigated faculty perceptions of the improvement and effort for achievement of the quality of nursing education through accreditation in baccalaureate nursing programs in 2006. Survey data from 190 professors of 33 accredited nursing schools were statistically analyzed using SPSS ver. 19.0 software with descriptive statistics, t-tests, and ANOVA. Through accreditation, about two-thirds of subjects perceived that the quality of education had 'improved' and the purposes of the accreditation were moderately successfully achieved (score 3.50). They also perceived their schools made a strong attempt (score 4.24) to assure quality. The perception scores of efforts to assure the quality of education varied significantly according to the characteristics of the subjects, the existence of a university hospital, the type of college, and the year of school founding. There were significant differences between the level of improvement in education and the extent of effort to assure the quality of education. Accreditation contributed to improved quality of nursing education except for some issues which need more consideration. To maintain high quality, the accreditation of baccalaureate nursing programs should be performed with continuity and on a regular basis.

• Journal of Advanced Marine Engineering and Technology
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• 제23권1호
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• pp.9-18
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• 1999

The present study is aimed to investigate flow characteristics of two-dimensional backward-fac-ing step by numerical approach. A convection conservation difference scheme based upon SOLA algorithm is used for the solution of the two-dimensional incompressible Navier-Stokes equations to simulate the laminar transitional and trubulent flow conditions at which the experimental data can be available for the backlward-facing step. The twenty kinds of reynolds number are used for the calculations. In an effort to demonstrate that the reported solutions are dependent on the mesh refinement computations are performed on seven different meshes of uniformly increasing refinement. also to investigate the result of inflow dependence two kinds of the inflow profile are chosen for the laminar flow. Irregular grid is adopted to minimize the errors on the satis-faction fo the discretized continuity. As criterion of benchmarking the result of numerical simula-tion reattachment lengthis used for the selected Reynolds numbers. The results of the present study prove the fact that the numerical predictions agree well with the experimental data and the flow characteristics are shown at the backward-facing step.

• 대한기계학회논문집B
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• 제20권4호
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• pp.1416-1425
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• 1996

A numerical method has been proposed to predict 3-dimensional flow in a duct system with multiple outlets. For the duct system, it is supposed that the pressure values are given at multiple outlets while the velocity profile is given at a inlet. To maintain the continuity of pressure distribution between main and branch duct, present method allows that the pressure value taken from analysis of branch duct can be converted to the main duct analysis. The result from present method which can handle the pressure boundary condition closely coincided with that from regular method which can handle the velocity boundary condition only. Furthermore the flow distribution from present method showed good agreement with that from the single block method. From the comparison of the present method with the total pressure method used for engineering duct design, 13% of discrepancy in pressure loss was shown between the main duct inlet and the branch duct outlet.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권1호
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• pp.105-110
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• 2011

Some research work on CFD computation of ship motions and added resistance in waves for a high speed trimaran is carried out in this paper. The governing equations, Reynolds Averaged Navier-Stokes and continuity equations are discretized by finite volume method. Volume of fluid method is adopted to deal with the nonlinear free surface. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling flexible flap wavemaker motions, and the outgoing waves are dissipated inside an artificial damping zone located at the rear part of the wave tank. In this paper, the computed results of ship motion and added resistance for a high speed trimaran are presented. The results of seakeeping experiment for the high speed trimaran carried out in CSSRC towing tank are also presented in this paper. Rather good agreements are shown between the computational and experimental results. The work in this paper provides a numerical tool for the study of seakeeping performance of high speed trimarans.