• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.53-60
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• 2003

This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.454-460
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• 2013

We present qualitative and quantitative component analyses on compound explosives via Terahertz time-domain spectroscopy (THz-TDS) based on a combination of wavelet thresholding and wavelength selection. Despite its importance, the field of signal processing of THz signals of compound plastic explosives is relatively unexplored. In this paper, experiment results from explosives Composition B-3 and Pentolite are newly presented, suggesting a novel signal processing procedure for in situ compound explosives detection. The proposed signal processing method demonstrates effective component analysis even in noisy and humid environments, showing significant decrease in component concentration percentage error of approximately 22.7% for Composition B-3 and 48.8% for Pentolite.

• Journal of The Korean Astronomical Society
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• v.32 no.1
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• pp.17-39
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• 1999

We investigate dynamical evolution of globular clusters with multi-mass component under the Galactic tidal field. We compare the results with our previous work which considered the cases of single-mass component m the globular clusters. We find the followings: 1) The general evolutions are similar to the cases of single-mass component. 2) There is no evidence for dependence on the orbital phase of the cluster as in the case of single-mass component. 3) The escape rate in multi-mass models is larger than that in the single-mass models. 4) The mass-function depends on radius more sensitively in anisotropic models than in isotropic models.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.241-244
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• 2006

본 논문은 지구자계를 이용하여 3축 자계센서의 수직 성분자계를 보정하는 방법과 장치를 제안한다. 자계센서는 설치각도 및 이득오차에 의해 출력 특성이 변화한다. 따라서 자계센서를 사용하기에 앞서 보정이 필요하다. 지구에서 발생되는 지구자계를 이용하여 간편하게 센서의 설치각도 및 이득오차에 의한 영향을 보정하였으며 이를 위한 장치를 설계하였다. 제안한 방법은 실험을 통하여 실용성을 검증하였다.

• Korean Journal of Materials Research
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• v.15 no.11
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• pp.711-716
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• 2005

The effects of change in the component of bonding materials in carbon nanotube cathode (CNT-cathode) on field enhancement and field emission characteristics were investigated. The field enhancement factor$\beta$ was dependent on the electrical conductivity of the bonding materials. The use of frit glass as a bonding material showed a higher field enhancement factor and better field emission characteristics than an Ag paste. The reason for why the frit glass showed better field emission characteristics can be summarized as follows. First, a frit glass improves the real aspect ratio of CNTs compared to an Ag paste. Second, the number of CNTs in CNT-cathodes is considerably reduced because the CNTs were extensively oxidized during $390^{\circ}C$ heat treatment in air atmosphere in the case of Ag paste.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1403-1412
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• 2011

This study performed a detecting research of promising R&D field utilizing intuitive methodology regarding OLED illumination industry. For this, 69 professionals of the illumination industry in Korea were composed as a panel to hold an in-depth interview and survey for 1 month. The study classified the OLED illumination industry as 4 fields of panel, material/component for panel, manufacturing equipment, and lighting system, and selected core technology for each field, and divided it into a total of 14 possible fields for R&D. As a result of evaluating the technological competitive power for each field, the field in Korea which received the highest technological competitive power was OLED panel, and contrarily, technological competitive power of material/component for OLED panel showed the lowest, which requires improvement Meanwhile, evaluating economical aspect, conformity to policy, and effectiveness of R&D in general, 7 promising R&D fields were selected. The 4 core technologies of OLED panel, which are, white, transparent, color change and flexible OLED manufacturing technology were evaluated as the most promising fields, and next, organic material for surface light source, material/component for substrate and equipment for forming large sized substrate were evaluated as promising fields.

• Fire Science and Engineering
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• v.23 no.4
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• pp.137-144
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• 2009

This paper was studied on the problem of field inspection tester of the photoelectric type smoke detector. The experiment objects were chosen 3 type's testers such as A type (incense), B type (dimethylpolysiloxane), C type (mixtures of hydrocarbon) which were used for performance checking of the photoelectric type smoke detector for the fire protection. The experimental methods were used reliability verification experiment, performance verification experiment and performance change of fire detector by smoke component. It was confirmed through the experiment that the testers had problems of smoke concentration condition and wind velocity condition and smoke component. Consequently, this paper verified that the field inspection testers of the photoelectric type smoke detector had problems in the inspection of fire protection.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.313-330
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• 1993

The propagating crack problems under dynamic plane mode in orthotropic material is studied in this paper. To analyze the dynamic fracture problems in orthortropic material, it is important to know the dynamic stress components and dynamic displacement components around the crack tip. Therefore the dynamic stress components of dynamic stress field and dynamic displacement components of dynamic displacement field in the crack tip of orthotropic material under the dynamic load and the steady state in crack propagation were derived. When the crack propagation speed approachs to zero, the dynamic stress component and dynamic displacement components derived in this study are identical to the those of static state. In addition, the relationships between dynamic stress intensity factor and dynamic energy release rate are determinded by using the concept of crack closure closure energy with the dynamic stresses and represented according to physical properties of the orthotrophic material and crack speeds. The faster the crack velocity, the greater the stress value of stress components in crack tip. The stress value of the stress component of crack tip is greater when fiber direction coincides with the crack propagation than when fider direction is normal to the crack propagation.

• Bulletin of the Korean Mathematical Society
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• v.55 no.6
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• pp.1823-1834
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• 2018

The position vector field x is the most elementary and natural geometric object on a Euclidean submanifold M. The position vector field plays very important roles in mathematics as well as in physics. Similarly, the tangential component $x^T$ of the position vector field is the most natural vector field tangent to the Euclidean submanifold M. We simply call the vector field $x^T$ the canonical vector field of the Euclidean submanifold M. In earlier articles [4,5,9,11,12], we investigated Euclidean submanifolds whose canonical vector fields are concurrent, concircular, torse-forming, conservative or incompressible. In this article we study Euclidean submanifolds with conformal canonical vector field. In particular, we characterize such submanifolds. Several applications are also given. In the last section we present three global results on complete Euclidean submanifolds with conformal canonical vector field.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.129-132
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• 2005

Recently, Domestic construction industry is confronted with a new phase by increasement of stock and elation of the concern about environment. In particular, the focus on remodeling as an altanative of the reconstruction system that squanders resources and creates massive construction waste, has increased. However, current remodeling methods are being obstructed factor, because design has not considered the remodeling at the beginning of the construction. The purpose of this study is to search for the improvement of component joint for efficient remodeling. Field survey is conducted on the components grouped by spaces(living room/bed room/kitchen/bathroom) of unit living at 6 construction sites in Seoul & countries. As a result, total 228 component joints are selected and classified according to interface condition and problem pattern.