• 한국전기전자재료학회논문지
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• 제26권6호
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• pp.425-428
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• 2013

In this paper, we present a novel hydrophilic coating material (Wellture Finetech, Korea) which can be utilized as a coating layer for anti-contamination for electrical and electronic system. The coating material was deposited on 4 inch silicon wafer with several different film thickness. The film thickness was controlled by spin coating speed. After curing of the film, we have scratched by permanent marker to check self-cleaning property of the film. Also we have executed several mechanical tests of the films. As the spin coating speed is increased, the film thickness was thinned from 230 nm to 125 nm. Contact angle of the film was lowered from $30^{\circ}$ to $12^{\circ}$ as the spin coating speed is increased from 700 to 2,500 rpm. On permanent marker scratched film surface coated at 1,000 rpm, we have poured regular city water to investigate self cleaning property of the film. The scratches were gradually separated from the film surface due to super-hydrophilicity of the film. Hardness of spin coated film was 9H measured by ASTM D3363 method. and adhesion of all film was 5B tested by ASTM D3359 method. Also, to get exact hardness value of the film, we have utilized a nano-indenter. As spin speed is increased, the hardness of film was increased from 3 GPa to 5 GPa.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권5호
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• pp.487-495
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• 2016

In the offshore project such as semi-submersible FPU and FPSO, the free fall type life boat called TEMPSC (Totally Enclosed Motor Propelled Survival Craft) has been installed for the use of an emergency evacuation of POB (People on Board) from the topside platform. For the design of life boat arrangement for semi-submersible FPU in the initial design stage, the drop height and launch angle are required fulfill with the limitation of classification society rule and Company requirement, including type of approval as applicable when intact and damage condition of the platform. In this paper, we have been performed the numerical studies to find proper arrangement for the life boats consider drop height in various environmental conditions such as wave, wind and current. In the calculations, the contributions from static and low frequency (LF) motions are considered from the hydrodynamic and mooring analysis as well as damage angle from the intact and damage stability analysis. Also, Air-gap calculation at the life boat positions has been carried out to check the effect on the life boat arrangement. The air-gap assessment is based on the extreme air-gap method includes the effect of 1st order wave frequency (WF) motions, 2nd order low frequency roll/pitch motion, static trim/heel and set down.

• 수산해양기술연구
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• 제28권1호
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• pp.10-20
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• 1992

The new course distances of a ship are considered to be the indices to indicate directly her abilities of course altercation. Generally, they have long been calculated by using the maneuvering indices obtained from her Z test. However, at sea actually the maneuvering indices can not sometimes be obtained according to ship's condition or circumstances and the new course distances can not be calculated. To find out other method to calculate the new course distances, in this paper the author analyzed them from a viewpoint of ship motion, and worked out a numerical formula to calculate them easily, using the data of ship's heading test. In order to check whether the presented method is applicable to actual ships or not, the experiment by them were also performed. The results obtained are summarized as follow: 1. The mean difference of the distance between two new course distances by the heading test and the maneuvering indices of the experimental ship was about 0.98% values of the ones by the maneuvering indices, when her heading were 10。, 20。 and 30。, using the rudder angle of 15。. These new course distances were therefore found to be almost same in values of the distance. 2. The mean difference of the distance between two new course distances by the heading test and the observation of experimental ship was about 1.16% values of the ones by the observation, when her headings were 10。, 20。 and 30。, using the rudder angle of 15。. These new course distances were therefore found to be almost same in values of the distance. 3. It is confirmed that the new course distances can be calculated easily by using the method of ship's simple heading test, without the observation or using the maneuvering indices. 4. It is considered to be helpful for the safety of shiphanding to draw curves of new course distances by ship's heading test and utilize them at sea.

• 척추신경추나의학회지
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• 제11권1호
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• pp.33-40
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• 2016

Objectives : To evaluate the foot indices using dynamic and static checking on healthy adult people. Methods : Foot indices analysis was performed for 46 students. Static checking practiced for Foot Pressure(FP) and Toe Pressure Difference(TPD) and dynamic checking was used for Vertical Axis Angle(VAA). Results : On gender, there was generally no statical significant difference, except RFP(Right Foot Pressure). The RFP of male was bigger than that of female. On age, in addition, there was similar tendency, only RFP had a positive correlation (r=0.35, p<0.05). Comparing foot indices on right and left, we found TPD and VAA had a tendency of pronation on left, but FP had a opposite tendency. On consistency of each foot index, discrepancy between TPD and VAA (39.47%) was lesser than combination of the others. Conclusions : According to foot indices among 46 healthy student, we found out that there is partially correlation between dynamic and static checking. We hope that the data we found will contribute to standardization of podiatry indices which provide medical guidance for cure of foot disease, supporting further podiatry research.

• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.437-444
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• 2008

Purpose: A number of techniques and materials have been used for periodontal regeneration and bone graft procedures with guided tissue regeneration(GTR) have been suggested as alternatives to osseous surgery in the management of local infra-bony defects. However, the long-term stability and treatment outcome following bone graft procedure of infra-bony defects is poorly documented. The purpose of this study was to assess radiographic change in infra-bony defects over 2 years after bone graft procedures with various graft materials. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients showed clinical and radiographic evidence of infra-bony defect(s). 44 sites of 34 patients aged 31 to 69 (mean age 48.3) were treated by bone graft procedure with a bone graft material. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. Result: We observed $1.15{\pm}1.95\;mm$ of bone fill, $0.40{\pm}1.19\;mm$ of crestal resorption, $1.55{\pm}1.77\;mm$ of defect resolution, and $40{\pm}44%$ of percentage of defect resolution. Deeper initial defect depth, narrower initial defect angle showed significantly greater bone fill, defect resolution, and % of defect resolution. But no significant difference was observed in graft sites and graft materials. Conclusion: If good oral hygiene maintenance and periodic recall check of patients is assured, bone graft procedure using various graft materials is one of the appropriate treatment modality for regenerative therapy of infra-bony defects.

• 한국가스학회지
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• 제19권5호
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• pp.13-19
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• 2015

본 연구에서는 보다 현실적인 파쇄균열 전파를 묘사하기 위해 수압파쇄균열 전파 모델을 개발하였다. 이 모델에서는 두 가지 균열 전파 기준을 적용하였다. 첫 번째는 균열의 발생각을 결정하기 위한 최대 접선응력 기준과 두 번째는 파쇄균열의 자연균열 통과 여부 기준이다. 본 모델의 검증 결과, 수압파쇄균열이 자연균열을 통과하는 양상이 실험값과 동일함을 확인하였다. 균열의 전파에 직접적인 영향을 미치는 요소인 최대수평응력 방향, 균열면의 마찰계수, 자연균열의 방향성에 대한 민감도 분석 결과, 이론적 기준에 적합하게 균열의 전파 방향과 통과 여부가 결정되는 것으로 나타났다. 기존의 수직 판형 균열 전파 모델과 본 모델을 비교하여 균열의 연결성과 유정 자극부피 측면에서 차이가 있음을 확인하였다.

• 대한건축학회논문집:계획계
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• 제35권3호
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• pp.59-66
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• 2019

In recent years, urban regeneration is focused on smart and pedestrian oriented development utilizing various mobility technology. The characteristics of walkways needs to reflect such development orientations. This research is the first step to find an adequate slope for ramp replacing stairs and shared by pedestrians, personal mobilities and powered wheelchairs. It aims to check if ramps on a recommended degree of angle by general guidelines are more preferred than stairs and find out what make difference of such preferences. Two surveys were conducted at $9^{\circ}$ and $9.6^{\circ}$ ramps coexisted with stairs at sequential and parallel location. The study on the survey result found that the general evaluation of $9^{\circ}$ ramp was better than $9.6^{\circ}$ ramp but $9^{\circ}$ ramp was not preferred than stairs while $9.6^{\circ}$ ramps was preferred. The difference of preferences was related to characteristics of stairs. The stair with shorter tread and riser next to $9^{\circ}$ ramp was evaluated much better than stairs next to $9.6^{\circ}$ ramp. Therefore the research concludes that $10.0^{\circ}$ which many guidelines recommend for the maximum slop of a ramp was not adequate for a ramp to replace stairs as a preferred means of vertical circulation. In addition the research found that the preference was sensitive to moving direction and gender especially in regards to comfort of stairs and safety of ramp. Most pedestrians chose a means of vertical circulation based on its comfort but pedestrian's evaluation of safety was most different based on moving direction.

• 대한조선학회논문집
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• 제59권1호
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• pp.55-63
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• 2022

A stranded ship means a ship which is stuck on a rock or a seabed, and cannot move by itself. The lightening plan is required to refloat the stranded ship. For this, we have to understand the forces and moments acting on the ship, which is composed of the gravity, buoyancy, and reaction force due to the touched area below the ship. This study defines those forces and moments, and proposed the calculation method to find the posture based on the static equilibrium. It is divided by two steps. In the first step, the magnitude and position of the reaction force are obtained based on the known information such as initial trim angle and draft of the ship. In the second step, the reaction force and the posture is calculated due to the three cases such as addition, reduction, and movement of the cargo. It is applied to three examples in order to calculate the reaction force, and the trim angle due to changes of the cargo. As a results, we successfully obtain the magnitudes and positions of forces acting on the stranded ship and to check the posture of the stranded ship.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제27권1호
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• pp.19-38
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• 2024

본 연구는 로봇을 활용한 수학 융합 인공지능교육 프로그램을 개발하고 적용하여 인공지능 및 수학적 개념에 대한 학생의 이해 특성을 분석하는 것을 목적으로 한다. 이를 위해 초등 인공지능교육 내용 기준을 분석하여 인공지능의 개념 요소를 추출하고, 이를 효과적으로 융합할 수 있는 수학과 성취기준을 파악하였다. 특히 로봇의 움직임을 활용하기에 적합한 각도 단원과 사각형 단원을 선택하여 그 성취기준을 인공지능교육 내용 요소와 융합하기 위해 수업을 재구성함으로써 5회기(총 15차시) 분량의 프로그램을 개발하였다. 이를 초등학교 4학년 1개 학급 22명을 대상으로 5개월에 걸쳐 적용하고 적용시 드러난 학생들의 이해를 인공지능 내용 주제별로 분석한 결과, 로봇을 활용한 수학 융합 인공지능교육 프로그램은 인공지능 원리 및 수학적 개념 이해에 도움이 되는 것으로 나타났다. 또한 로봇의 활용은 실행 과정 및 결과 도출까지 일련의 절차를 시각적으로 확인하도록 함으로써 학생들의 인공지능과 수학적 이해뿐만 아니라 수업 참여도를 제고하는 것으로 확인되었다.

• 한국측량학회지
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• 제28권2호
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• pp.247-254
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• 2010

SPOT 4 위성영상의 기하 왜곡을 보정하기 위하여 새로운 접근방법을 연구하였다. 우주공간에서 위성과 지구의 관계를 정립함으로서 새로운 조건 방정식을 유도하였다. 초기 위성에 대한 정보가 어떤 일정한 변화에 의해 왜곡이 있다고 가정하고, LOS(Line-Of-Sight) 벡터를 변화시켜 위성영상의 기하를 보정하는 LOS 벡터 조정 모델을 연구하였다. 본 모델을 증명하기 위하여 관측각이 큰 SPOT 4 위성영상을 대상으로 실험하였다. 또한, 정확한 실험을 위하여 GPS로부터 측량한 10개의 지상기준점(GCPs)과 25개의 검사점(check points)을 사용하였다. SPOT 4 위성영상에 주어진 초기 위성정보(위성 위치, 속도, 자세, 관측각 등)를 그대로 이용하여 계산한 위성영상 기하는 총 35개의 지상기준점과 검사점에 대하여 거의 일정한 변화량을 지녔으며, 이를 통해 SPOT 4 위성영상에 시선벡터조정모델을 적용할 수 있음을 확인하였다. 시선벡터조정모델을 적용하여 영상에 고르게 분포하는 지상기준점을 2점에서 10점까지 변화시키면서 검사점의 오차를 계산하였고, 25개 검사점 오차는 모두 1픽셀 미만이었다. 새로운 접근 방법인 이 모델은 2점 이상의 지상기준점을 이용하여 SPOT 4 영상 기하를 효과적으로 보정하였으며, 또한 SPOT 영상과 촬영방식이 동일한 고해상 위성영상에 대해서도 좋은 결과를 얻을 것으로 기대한다.