• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.288-294
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• 2010

In recent years, wind energy has been the world's fastest growing source of energy. This paper describes the structural design and analysis of composite blade for 2 kW-level HAWT (horizontal axis wind turbine). The aerodynamic design and force, which are required to design and analyze a composite blade structurally, are calculated through BEMT(blade element momentum theory) implemented in public code PROPID. To obtain the equivalent material properties of filament wound composite blades, the rule-of-mixture is applied using the basic material properties of fiber and matrix, respectively. Lay-up sequence, ply thickness and ply angle are designed to satisfy the loading conditions. Structural analysis by using commercial software ABAQUS is performed to compute the displacement and strength ratio of filament wound composite blades.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1233-1243
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• 1999

This study was done to investigate the lives of the daughters- in- law caring for parents with dementia and participate in their lives through having quality time with them Data were collected by depth interviews and interpreted through the hermeneutic circle as follows. These daughters-in-law have conflict between social custom and subjective self. They had ambivalence toward their demented partents-in- law and were fighting a battle between rationality and emotions in their mind. These daughters-in law and mothers-in- law did not get along and the parents' dementia aggravated the relationships. They were alienated from their family by the parents with dementia. The indifference of their family especially their husbands, made these subjects live in misery. They cared for the demented mother-in-law with hatred. Even though they had this yoke, there daughters- in-law were not able to throw off the shackles of convention.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.37-42
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• 1998

The important parts of the developing AGV model are the fabrication of each part and the design technology of body frame. In the present day, design of the body frame depends on the experience of the industrial place. the systematic data need for the optimal design of the frame for the case of model change. In this study, the strength of the early stage AGV(Automatic guided vehicle) is examined with the 3-dimensional finite elemnt method. In order to verify the finite element results, the computed results are compared with the experimental data from the strain-gage output. A New model was designed by rmoving some parts of the early staged(roughyly designed) model and choosing the thickness change of the rectangular-pipes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.169-176
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• 1995

Change detection is the technique to represent the change of pixel by pixel and band by band between $t_1\;and\;t_2$ times. In this study, authors analize the beach-sand movement using digital image analysis, interpolation and digital terrain model by leveling every years at a coastal area. This paper suggests the useful beach-maintainance plan based on the sand movement and its direction, direction and influence of ocean current, change of oceansand erosion and sedimentation, and area of erosion and sedimentation.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.119-132
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• 2010

In this study, 2-dimensional inundation analysis for Taehwa watershed in Ulsan metropolitan city was conducted to analyze flow behaviors, inundation depth and inundation stage, considering the building effect. Lidar having the interval of 1 m was employed to generate topographic data with 10m interval, and building data extracted from digital map was combined with the constructed topographic data for 2-dimensional inundation analysis. A few scenarios were constructed for the analysis to provide an effective and accurate inundation analysis method through analyzing the results. The disagreement based on the areas of inundation showed over 10% between the cases with and without consideration of building effect. The maximum inundation depth without considering the effects of buildings was 0.29m higher than that with considering the building effects. On the contrary, the maximum inundation stage with consideration of building effects was 0.49m higher than that without consideration of building effects.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.399-424
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• 2014

Although teacher preparation programs are important for prospective teachers to build a foundation of teaching expertise, there has been lack of research in this area. This paper analyzed in what ways prospective teachers' ability in describing and commenting on elementary mathematics instruction has been changed while they were taking in the course of teaching elementary school mathematics. The results of this study showed that in late description the teachers tended to notice the core flow of a lesson and the use of instructional strategies appropriate to the mathematical content to be taught. They also tended to comment on instructional strategies and mathematical discourse from the teacher's perspective and evaluated them without alternative approaches. A noticeable change occurred in late comments wherein prospective teachers considered both the teacher and students, supported their comments by theories they had learned through the course, and interpreted the classroom events they had noticed. Building on these results, this paper closes with implications of teacher education programs to enhance prospective teachers' ability to analyze elementary mathematics lessons.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.485-492
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• 2001

In this paper, electro-magnetic numerical analysis of MFL(magnetic flux leakage) method is presented. For the electromagnetic numerical analysis, 2-D FEM(finite element method) is used. The magnetic vector potential is used as a variable. The analysis of the magnetic field considering the magnetic nonlinearity is performed for the effect of the magnetic salutation. For the verification of the validity of the numerical simulation results, by using the lab-made experimental setup, non-destructive inspection is performed. The SM 45C carbon steel is used as a specimen and the artificial defects are made on the specimen. The non-destructive testing for the detection of the defect is performed. The results according to the variation oi the defect depth and the defect shape are obtained. The experimental results are compared to the numerical ones, and we conclude that the numerical results are similar to the experimental ones. So the possibility of simulation of the MFL by using the numerical analysis is shown in this paper.

• Communications of Mathematical Education
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• v.19 no.2 s.22
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• pp.453-469
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• 2005

기하는 수학의 기초를 이루는 중요한 영역이다. 그러나 기하교육을 위한 프로그램 설계와 교수전략에 대한 연구가 부족한 실정이다. 그러므로 현장의 수학교사들에 의한 프로그램개발과 동시에 프로그램과 지도방법을 통합하는 수학교사들의 지속적인 연구가 절실히 요구된다. 이에 본 연구는 영재의 특성들을 고려하고 교사 중심의 강의식 수업보다는 토론, 발표, 세미나에 적합한 프로그램을 구안해 보았다. 프로그램 설계의 내용적 면에서는 기하학의 한 방법인 해석기하학과 현재 고등학교에서 다루는 Euclid 초등기하의 한계를 넘어 공선(共線), 공점(共點)의 비계량적 개념의 사영기하학을 도입하였다. 그리고 프로그램을 운영하는 방법적인 면에서는 문제제시단계, 문제해결단계, 수학적 개념추출단계, 수학화 단계, 확장단계의 단계별 절차를 두었다. 이와 같은 수학영재교육 프로그램의 설계 및 교수전략의 목적은 수학영재들을 새로운 문제와 지식을 제안하고 생산하는 수학 창조자를 만들고자 하는데 있다.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.74-88
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• 2010

In this study, the points of LiDAR were modified in order to generate various DEM resolutions by applying LiDAR data in Ulsan. Since the LiDAR data have points with 1m intervals, the number of points for each resolution was modified to the size of 1, 5, 10, 30, 50, 100m by uniformly eliminating the points. A runoff analysis was performed on Taehwa river and its tributary, Dongcheon, with 200 year rainfall exceedance probability. 2-dimensional inundation analysis was performed based on the density of LiDAR data using FLUMEN, which was used to establish domestic flood risk map. Once DEM data obtained from LiDAR survey are used, it is expected that the study results can be used as data in determining optimal grid spacing, which is economical, effective and accurate in establishing flood defence plans including the creation of flood risk map.

• Composites Research
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• v.15 no.6
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• pp.1-7
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• 2002

In VARTM process where a sacrificial medium is used to facilitate the resin flow, the velocity of resin varies drastically between the sacrificial medium and the fiber preform. Although the thickness-to-length ratio of a VARTM product is usually small, a 3-D analysis is prerequisite to analyze the lead-lag flow in the two different media. The problem associated with the full 3-D analysis is the CPU time. A full 3-D numerical mesh comprising large number of nodes requires an impractical CPU time on average computer platforms. In this study, a dual-scale analysis technique was developed. The flow analysis for the entire calculation domain was conducted in 2.5-D, and the 3-D analysis was performed for a small area of special concern. In some numerical examples, the local 3-D analysis could discover an eccentric flow pattern as well as the lead-lag flow that will inevitably be neglected in 2.5-D simulations. The global-local analysis technique practiced in this study can be used to analyze the intricate flow of resin through non-uniform media in affordable CPU times.