• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.99-109
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• 2000

Elastic dynamic responses analysis program for ship hulls considering slamming impact loads due to the voyage in large amplitude waves is developed. Ship hull structures are modeled by a thin-walled beam model in order to consider effects of shear deformation. The momentum slamming theory is used to derive nonlinear hydrodynamic forces considering intersection between wave particles and ship section. For the validation of the developed computer program, motions of a V-shaped simple section model and S-175 standard container model are calculated and analyzed. In each numerical example, time histories of relative displacement, velocity and vertical bending moment of a ship section are derived, considering the effect of slamming impacts in various wave conditions.ures near the free surface as well as the wake of the hydrofoil.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.939-947
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• 2001

This paper presents the penetrated electric fields and resonant frequencies inside a metallic enclosure with aperture excited by an external dipole source. In the theoretical analysis, integral equations for the current distribution and electric field distributions on the aperture are solved by applying Galerkin\`s method of moments. The results show that the electric fields inside metallic enclosure is maximum at the near the aperture and resonant frequencies are the same as calculated of the enclosure without aperture. To verify the theoretical analysis the electric field inside enclosure and resonant frequencies are compared with the experimental results.

• Geotechnical Engineering
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• v.13 no.3
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• pp.53-62
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• 1997

Analytical studies were conducted to develop the Spectral-Analysis-of-Surface-Waves (SASW) method for underwater use. For the precise estimation of the in-situ soil stiffness profile from SASW measurements, it is essential to determine economical and reasonable theoretical dispersion curves reflecting various experimental conditions. In this paper, therefore, analytical methods are mainly discussed, which were developed to determine theoretical dispersion curves of surface waves propagated along the soil-water interface. Application of the analytical methods is then illustrated by an example involving estimation of a stiffness profile through a forward modeling process of SASW measurements. Applicabilities of the SASW method as well as the developed analytical methods are evaluated, respectively, from the example.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.1-6
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• 2006

This paper predicts the stall characteristics of three-dimensional wings. An iterative decambering approach is introduced into the nonplanar lifting surface method to take into consideration the stall characteristics of wings. An iterative decambering approach uses known airfoil lift curve and moment curve to predict the stall characteristics of wings. The multi-dimensional Newton iteration is used to take into consideration the coupling between the different sections of wings. Present results are compared with experiments and other numerical results. Computed results are in good agreement with other data. This scheme can be used for any wing with the twist or control surface and for wing-wing configurations such as wing-tail configuration or canard-wing configuration.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.36-42
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• 2010

본 논문은 태양열이용 냉난방시스템 중에서 실제로 액체흡수제를 재생하는 재생탑 내의 충진층에 있어서의 열 및 물질전달의 실험치와 이론적 해석에 의한 결과치와의 비교를 나타내고 있다.특히 물질전달의 극대화를 위하여 충진층 내에서 공기와 흡수제의 접촉면적을 크게 할 필요가 있는데,이를 위해서 본 실험에서는 직경이 3cm인 플라스틱제 충진재를 사용하였으며, 흡수제로는 저농도의 염화리튬 수용액이 사용 되었다. 충진층 내에서의 최적 높이를 예측하기 위하여 해석의 모델인 실험장치를 직접 제작하여 실험을 수행하였고, 이론 해석에 있어서 체적 열전달을 고려한 정상상태를 모델화하여 해석하였다. 이 결과, 충진층 내에서 실험치와 이론적인 계산치가 잘 일치함을 알 수 있었으며, 충진층의 높이가 2m 이상인 경우에는 높이에 따른 재생량의 차이가 없어서 없음을 알 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.950-954
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• 2003

This paper presents the delivered power and reflection coefficient in metallic shielding enclosure excited by the interior source, which are evaluated with the method of moments, and describes a method for reducing the radiation of electromagnetic fields in the cavity by putting lossy dielectric material in one inside wall. In this paper we introduce carbon polystyrene-foam as lossy dielectric material and observe it's effects of reduction when the thickness and permittivity of lossy dielectric material are changed. The results show that the reduction of the electromagnetic radiation can be achieved by controlling the amount of carbon in lossy dielectric material. The theoretical analysis is verified by the measured delivered power.

• Composites Research
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• v.24 no.5
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• pp.1-8
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• 2011

This paper presents the results of theoretical analysis and experimental test to show the size effect on the fiber strength of filament would pressure vessel. First, a series of fully scaled hoop ring tests with filament would carbon-epoxy were conducted, which exhibited a remarkable size effect on the fiber strength. Next, the failure analyses using WWLM(Weibull Weakest Link Model) and the SMFM(Sequential Multi-step Failure Model) were performed and compared to the hoop ring test data, as well as to unidirectional specimens test data from the literature. It was found that the analysis results significantly underestimated the fiber strengths compared to the test data. In this study, a modified SMFM was proposed through the modification of the length size effect. The fiber strengths from modified SMFM analysis showed good agreement with the test data.

• Journal of Christian Education in Korea
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• v.61
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• pp.61-80
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• 2020

This study mark a high complexity of the field, which is further enhanced by the fact, that these discussions are transposed into religious education and professionalism research relating to religious education teachers. It seriously considers very unique semantics and practice of leadership emerge then, crosswise and as a background to the educational hermeneutics. Obviously, besides didactic implications, professional ethical implications in an elementary sense are also at play here. The researcher will proceed in four steps: Firstly, I examine aspects of professionalism theory, into which, secondly, professional ethical considerations are entered in their significance for the topic of leadership, then deepen this through discourse-theoretical considerations before finally, fourthly, perspectives are opened up.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.645-652
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• 1986

For the analysis of equi-biaxial tension, the Lankford values at the various strain levels were measured experimentally at first. It was clarified that the R values depend on strain to a great extent and based on this result, the analysis of the equi-biaxial tension was carried out. Hill's new yield criterion was used to predict the stress-strain curves theoretically. The value of new parameter, m for the coincidence of the theory with the experiment was 2.1. It is desired that the optimum R-value in the case of m=2.1 is measured at strain, 15% for the reasonable correlation between theory and experiment.

• Journal of the Korean Society of Safety
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• v.7 no.1
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• pp.39-45
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• 1992

The impulsive stress and wave propagation of a glass/epoxy laminate subjected to the transverse low-velocity impact of a steel ball are investigated theoretically and experimentally. A plate finite element model based on Whitney and Pagano's theory In consunchon with experimental contact laws is used for the theoretical investigation. The specimens fo, statical indentation and impact test we composed of ［0/45/0/-45/0］$_{2s}$ and ［90/45/90/-45/90］$_{2s}$ stacking sequences and have clamped-simply supported boundary conditions. Finally, these two results are compared and then the impulsive stress and wave propagation characteristics of this laminated composite are studied.ied.