• Proceedings of the Korean Society For Composite Materials Conference
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.260-263
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• 2005

Fatigue fracture behavior of a hybrid joint between side-panel and under-frame by riveting and adhesive bonding has been evaluated. Two kinds of joint specimens based on real geometry were fabricated for shearing test as well as bending test. Static and cyclic loadings were used for fatigue assessment. Fatigue fracture results obtained by such experiments were reflected in modifications of design parameters of the hybrid joint.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제28권5호
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• pp.545-552
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• 2004

The purpose of this study is to improve the prediction ability of the atomization and vaporization processes of GDI spray. Several models have been introduced and compared. The atomization process was modeled using hybrid breakup model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed TAB (APTAB) model. The vaporization process was modeled using Spalding model and Abramzon ＆ Sirignano model. Exciplex fluorescence method was used for comparing calculated with experimental results. The experiment and computation were performed at the ambient pressure of 0.1 MPa, 0.5 MPa and 1.0 MPa and the ambient temperature of 293k and 473k. Comparison of calculated and experimental spray characteristics was carried out and the calculated results of GDI spray showed good agreement with experimental results.

• Proceedings of the KSME Conference
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.943-948
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• 2000

The Twin-fluid Swirl Nozzles are used in many parts of the industry to produce homogeneous spray. This study is to investigate the effects of outer air swiller and inner water swiller on atomization of liquid.. The experiment was carried out with increasing air-flow rate at constant liquid-flow rate and with changing outer air swiller angle and inner water swiller angle. A Particle Dynamics Analyzer(PDA) was used to measure drop size, mean and ms values of axial velocity, number density and Sauter mean diameter(SMD). The axial mean velocity and SMD of droplets were measured along the center line and radial directions. It was found that the higher air flow-rate resulted in the smaller Sauter mean diameter of liquid spray and the higher axial mean velocity of droplets. This experimental results will be conveniently used for the preliminary design stage of twin-fluid nozzle development.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 추계학술대회
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• pp.466-471
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• 2003

The purpose of this study is to obtain the accurate prediction for the atomization and vaporization processes of GDI spray. Atomization process is modeled using hybrid model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed TAB (APTAB) model. Vaporization process is modeled using Spalding model and Abramzon & Sirignano model. To obtain the experimental results for comparing with calculated results, the cross-sectional images of liquid and vapor phases and SMD distribution were acquired by exciplex fluorescence method and Phase Doppler Analyzer respectively. The experiment and computation was performed at the ambient pressure of 0.1 MPa, 0.5 MPa, 1.0 MPa and the ambient temperature of 293K, 473K. The calculated results by modified KIVA-II code show good agreement with experimental results.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1745-1747
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• 2002

This paper describes the effect of secondary surges entering low voltage side on the primary winding of pole transformers. After having connected the secondary winding by 4 different methods, surge voltages were applied to the low voltage side, and voltage waveforms were measured at a surge applied point and a high voltage bushing terminal. The measured voltages were compared by the waveform, magnitude and damping characteristics with each connection. As a result, the voltage waveforms induced by the secondary surges were different one another with each connection, especially, the conventional connecting method for 2 voltage sources was far different from the present method supplying only 1 voltage source in shape of the voltage waveform.

• The KSFM Journal of Fluid Machinery
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• 제4권2호
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• pp.22-28
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• 2001

This study was performed to evaluate the dynamic behavior of turbo pump unit. The acceptable separate margin of $1^{st}$ critical speed was obtained by the use of elastic-ring inserted ball bearing, while the poor separate margin of $1^{\st}$ critical speed was appeared in the case without the elastic-ring. In addition, the results show that the stiffness and damping of plain seals give more separate margin of $2^{nd}$ critical speed. However the wear or the failure of seals could reduce the $2^{nd}$ critical speed near the operating speed.

• Proceedings of the Korean Society for Information Management Conference
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• 한국정보관리학회 2005년도 제12회 학술대회 논문집
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• pp.157-164
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• 2005

지금까지 전자저널 서비스를 대상으로 한 연구는 정보원으로써의 전자저널에 대한 접근성의 문제나 비용문제에 중점을 두고 이루어져왔으며, 전자저널 서비스에 대한 이용자집단의 정보이용행태에 관한 연구는 대학교수를 대상으로 수행된 것 외에는 거의 찾아볼 수가 없었다. 본 연구의 목적은 대학도서관의 주요 이용자집단 중의 하나인 대학원생, 특히 인문계열과 공학계열 대학원생들의 전자저널에 대한 정보 요구 및 이용행태에 관해 과학적${\cdot}$체계적인 분석을 통하여 대학도서관이 효율적인 전자저널 서비스를 수행하는데 있어서의 기초 자료를 제공하는데 있다.

• Physical Therapy Korea
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• 제5권1호
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• pp.51-62
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• 1998

Conversion disorder is defined as a specific and enduring sensorimotor dysfunction that contradicts known neurological or musculoskeletal pathology or physical findings. The patient with conversion symptoms unconsciously adopts these symptoms to convert their psychological stress to a physical phenomenon. Conversion disorder often involves the mimicry of organic symptoms similar to those experienced by a relative or an acquaintance. Because conversion symptoms are produced by psychological stress, specific treatment strategy and reinforcement program are needed for treatment. Treatment comprises avoiding unnecessary medical tests and removing symptoms by using graded exercises given by physical therapists. Clinical therapists must maintain a continuous and detailed follow-up to completely recover from conversion symptoms. The goal of treatment is to emphasize health rather than disease, to resolve physical symptoms, and to prevent recurrence. This study looks into the case reports of 4 patients diagnosed with conversion disorder.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1714-1716
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• 1998

The surface breakdown problem has plagued the development of high solid state for more than 30 years, but the physical basis for this flashover phenomenon is still not understood. The only way to overcome those problem and has a workable compact solid state switch is to passivate the surface by a solid state dielectric material, to coating/encapsulation the device in an insulting medium. In this paper, characteristics of flashover in high field Si-dielectric system behavior under high electric field is discussed.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.559-567
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• 2018

In this paper, we propose a new load forecasting method for smart air conditioning (A/C) based on the modified thermodynamics of indoor temperature and the unbiased finite memory estimator (UFME). Based on modified first-order thermodynamics, the dynamic behavior of indoor temperature can be described by the time-domain state-space model, and an accurate estimate of indoor temperature can be achieved by the proposed UFME. In addition, a reliable A/C load forecast can be obtained using the proposed method. Our study involves the experimental validation of the proposed A/C load forecasting method and communication construction between DR server and HEMS in a test bed. Through experimental data sets, the effectiveness of the proposed estimation method is validated.