• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.2
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• pp.10-14
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• 1980

In this paper, the second harmonic distortion of the DH L.D. is analyzed using dynamic and static rate equations. In this analysis the modulation current Jm is changed by varang the iinjection current with the relation of where m stands for modulation index. It is showed that relative harmonic distortion ( ) has a peak exactly at the threshold current. It is also confirmed that this method is simople and more accurate than previously reported methods in the decision of the threshold current.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.2
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• pp.90-103
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• 1997

A numerical procedure is described for predicting the motion and structural responses of the very large floating offshore structures supported by multiple 3-D floating bodies of arbitrary shape in multi-directional irregular waves. The developed numerical approach taking into account of the hydrodynamic interactions among the multiple floating bodies is based on a combination of the 3-D source distribution method, the wave interaction theory, the finite element method and the spectral analysis method to get the significant values of the dynamic responses in the multi-directional irregular waves. The effects of wave interactions and directionality on the dynamic responses of a very large offshore structure, which is semisubmersible ring type, are numerically examined.

• Solar Energy
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• v.11 no.1
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• pp.50-60
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• 1991

A centrifugal pump was selected as a basic study, for it was utilized widely at the industry among various types of pumps. The purpose of this study was to develop the software for design of centrifugal pump. The step of this design was divided into two stages. First, the impeller was designed by the experiences and theory of A.J.Stepanoff, and the head was checked whether the design of impeller was acceptable. Second, the volute chamber was designed by the Archimedes spiral. Then, These procedures of impeller and volute chamber were developed into the software in C-language. Checked the validity of the developed software, the results were consistent with the actual pump produced domestically.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.161-176
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• 1993

For the purpose of assessing structural integrity at a level of complexity and accuracy appropriate for the situation, integrity assessment methods are formulated with the following methods. One is three-tier assessment method of the revised BSI PD 6493 which considers stable crack growth effect, the others are limit load analysis which estimates the plastic collapse load and stability assessment method which considers stable crack growth of ductile material exactly using J-integral and tearing modulus. Besides, integrity assessments for center cracked panel(CCP) specimen and the circumferential through-cracked pipe are carried out and reliability analysis is accomplished by the first order reliability method which is one of the conventional reliability methods. Also the accuracy of the present method is verified by Monte Carlo method.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.749-760
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• 2016

The purpose of this study was to identify the effects influencing path behaviors of pre-service childcare teachers to present the educational and social welfare measures for promoting children's character development and preventing the alienation of the elderly. The subjects for this study are 176 students who completed the childcare teacher course in four universities located in G city and J province. The scale of this study utilized modified, supplemented scale used in previous studies[1][2] that was constituted for a newly transformed model based on planned behavior theories. The contents of research design include salience beliefs such as attitude beliefs, normative beliefs, control beliefs, etc. as well as a model of planned behavior theories such as attitudes, subjective norms, perceived behavior control, behavior intension, behavior, etc. This study conducted frequency analysis and regression analysis for the data collected by using the SPSS 18.0 for Windows. From the results of verification, all hypothesis was supported. Thus, usefulness of this theory was reconfirmed, and the results of this study are to be utilized as basic materials for professionals who make every endeavor in a perspective of children's character development and in a perspective of reducing alienation phenomenon of the elderly.

• Archives of design research
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• v.12 no.2
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• pp.185-196
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• 1999

It has been known that deconstruction has affected various fields as literature, architecture, an, film, industrial design, and so on. Especially, deconstruction has applied into a wide scope of the design related fields through diverse ways and the results also show that there is a great potentiality in the ways of it's expression with different styles. Deconstruction design has been approached in connection with post-modernism, deconstruction theory of J. Derrida and pluralistic post industrial society. In particular, it is obvious that deconstruction philosophy has deeply affected the fields of visual design and typography which are mostly communicated with symbols and texts. This study intends to examine how the deconstruction theory has been practically applied into the typography by analyzing the change of deconstruction typographic styles and exploring the distinctiveness of the change.

• Journal of the Korean Ceramic Society
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• v.38 no.8
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• pp.693-697
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• 2001

고상반응법으로 이론 밀도의 약 92%의 소결 밀도를 갖는 입방정계의 새로운 이온전도체 L $a_{2-x}$S $r_{x}$M $o_{2-y}$C $r_{y}$ $O_{9-{\delta}}$(x=0, 0.05, y=0, 0.1)를 제조하였다. 교류 복소임피던스는 3$50^{\circ}C$~90$0^{\circ}C$의 온도범위에서 공기중에서 측정하여, EQUIVCRT 모델링 소프트웨어로 해석하였다. 상 전이온도인 58$0^{\circ}C$ 전.후로 임피던스 스펙트럼에 큰 차이가 있었으며, 전기전도도는 L $a_2$M $o_2$ $O_{9}$ 시편의 경우 7$50^{\circ}C$에서 3$\times$$10^{-2}$ S$cm^{-1}$ /로 우수하였으며, 활성화 에너지는 고온 상 영역에서는 0.89 eV, 저온 상 영역에서는 1.12 eV이었다. 순수한 L $a_2$M $o_2$ $O_{9}$과 비교하여 Cr 치환효과는 크지 않았으나, Sr 치환 시에는 상 전이온도의 감소와 전기전도도의 증가 현상을 보였으며, 전이온도 부근에서의 전기전도도 변화 폭은 작았다.다.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.79-86
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• 2005

The external conditions for estimating dynamic wind loads of wind turbines, such as the turbulence, the extreme wind, the mean velocity gradients and the flow angles, are simulated over GangWon Wind Energy Test Field placed in one of the most complex terrain in Korea. Reference meteorological data has been gathered at a height of 30m from 2003 to 2004 with a ultrasonic anemometer. The absolute value of the spectral energy are simulated and the verification of this prediction has been carried out with comparing to the experimental data. The most desirable place for constructing new wind turbine are resulted as Point 2 and Point 3 due to the lower value of Turbulence Intensity and the higher value of wind resource relatively.

• Progress in Medical Physics
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• v.23 no.3
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• pp.145-153
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• 2012

In this study, we quantify the residual motion artifact in 4D-CT scan using the dynamic lung phantom which could simulate respiratory target motion and suggest a simple one-dimension theoretical model to explain and characterize the source of motion artifacts in 4DCT scanning. We set-up regular 1D sine motion and adjusted three level of amplitude (10, 20, 30 mm) with fixed period (4s). The 4DCT scans are acquired in helical mode and phase information provided by the belt type respiratory monitoring system. The images were sorted into ten phase bins ranging from 0% to 90%. The reconstructed images were subsequently imported into the Treatment Planning System (CorePLAN, SC&J) for target delineation using a fixed contour window and dimensions of the three targets are measured along the direction of motion. Target dimension of each phase image have same changing trend. The error is minimum at 50% phase in all case (10, 20, 30 mm) and we found that ${\Delta}S$ (target dimension change) of 10, 20 and 30 mm amplitude were 0 (0%), 0.1 (5%), 0.1 (5%) cm respectively compare to the static image of target diameter (2 cm). while the error is maximum at 30% and 80% phase ${\Delta}S$ of 10, 20 and 30 mm amplitude were 0.2 (10%), 0.7 (35%), 0.9 (45%) cm respectively. Based on these result, we try to analysis the residual motion artifact in 4D-CT scan using a simple one-dimension theoretical model and also we developed a simulation program. Our results explain the effect of residual motion on each phase target displacement and also shown that residual motion artifact was affected that the target velocity at each phase. In this study, we focus on provides a more intuitive understanding about the residual motion artifact and try to explain the relationship motion parameters of the scanner, treatment couch and tumor. In conclusion, our results could help to decide the appropriate reconstruction phase and CT parameters which reduce the residual motion artifact in 4DCT.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.1
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• pp.80-87
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• 2001

This article shows how general software-ergonomic principles are successfully applied in the design of user friendly graphical interfaces. A theoretical model(WOB-Model) is derived from empirical studies and validated in the development of several systems. It provides basic principles within a well-balanced framework and leads to concrete design guidelines. The user tests with the software shows that many of the common usability problems can be eliminated.