• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.795-796
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• 2011

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.166-167
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• 2003

파랑ㆍ흐름의 공존장에서 그 간섭작용은 Tidal inlet 와 하구부근와 같은 천해영역에서 중요한 물리적 현상이다. 이러한 파ㆍ흐름간섭현상은 파랑의 파고, 스펙트럼과 파향등을 현저하게 변화시키고, 하구와 inlet부근에 출현하는 사주(砂洲)등의 발생기구 및 해빈 안정화에 관계하는 중요한 요인이기 때문에 이에 대한 적절한 해석이 필요하다. 본 보고에서는 확장형 부시네스크방정식을 토대로 한 수치모델을 통하여 파ㆍ흐름 공존장에서의 적용성을 검토하고자 한다. (중략)

• Journal of Industrial Technology
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• v.9
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• pp.109-117
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• 1989

In the finite element analysis of semiconductor devices analysis, the solution often be diverged due to the numerical instability of discretized equations. To overcome this problems, a noble finite element code which guarantees a successful convergence is developed. The factor of divergence in the current continuity equation of semiconductor governing equations is derived using stability test and an adaptive mesh refine scheme is introduced to eliminates the divergence properties. A test calculation of GaAs MESFET model reveals that the proposed scheme has a robust self-convergence property and is suitable for the semiconductor devices analysis.

• 전기의세계
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• v.42 no.8
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• pp.41-54
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• 1993

PSS는 향후 장기적인 전력공급 안정화를 위한 기술개발이나 기술력 향상에 전자계산기 이용기술과 더불어 상호 보완적으로 크게 이용되어야 한다. 더불어 전력회사 뿐만 아니라 관련 산업계, 학계까지를 망라한 우리나라의 전력기술 기반구축과 전문 기술인력의 양성을 위하여 PPS의 이용은 필수적인 것으로 생각된다. 기본적인 PSS의 기능 및 이용분야를 종합적으로 다시 한번 요약하면 아래와 같다. - 전력 계통 특수 기술현상 해석 - 현장 실증시험의 대체 및 신규 도입기술의 사용전 성능시험 - 고급전문 기술인력의 확보(교육훈련, 유치 및 양성) - 홍보 및 이해증진(전력계통 관련기술의 역할 및 중요성)

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.742-745
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• 1993

In this paper, instantaneous current tracking control inverter is applied to photovoltaic system and then optimum operating area is described by state space average method for optimum design of maximum output control. Also control system is realized by DSP and excellence of system shows the effectiveness of inverter system using the instantaneous control method.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1660-1661
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• 2007

수 처리 분야의 통합시스템을 구현함에 있어 이기종 장비 간의 데이터 연계는 프로그래머의 통신 프로그래밍 작업으로 매번 개발을 하여하는 문제점을 가지고 있다. 이로 인해 시스템의 안정화에 많은 시간 및 인력이 투입되고 있다. 본 연구는 인터프리터 엔진을 활용하여 엔지니어가 엔지니어링 한 데이터 (통신 스크립트)를 번역, 해석, 자동동작 시켜 별도의 프로그래밍 작업(개발)없이 엔지니어링으로만 통합 시스템의 감시 및 제어를 구축 가능케 프로토콜 편집기를 개발 하여 신뢰성 높은 시스템을 구축키 위한 내용이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.5
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• pp.419-426
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• 2018

For an orbit transfer in a space exploration mission, a solid or liquid rocket booster is included at the last stage of the launch vehicle. During the orbit transfer, thrust misalignment can cause a severe orbit error. Three axis attitude control or spin stabilization can be implemented to minimize the error. Spin stabilization technique has advantages in structural simplicity and lightness. One of ways to apply the spin stabilization to the payload is to include a spin table system in the launch vehicle. In this paper, effect of the spin table system on separation dynamics of the payload is analyzed. Simple model of the spin table to mimic basic functions is designed and simulation environment is established with the model. Effect of the spin table is tested by evaluating separation dynamics of a payload with and without the spin table. Analysis on tolerance effect of separation spring constant on separation dynamics of a payload is conducted.

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.745-754
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• 2007

This paper presents a unified modeling technique for tension stiffening effect in structural concrete members. The model is mathematically derived from the bond stress-slip relationships which account for splitting crack. The relationships in CEB-FIP Model Code 1990 and Eurocode 2 are employed together with the assumptions of a linear slip distribution along the interface and the uniform condition of concrete tensile contribution for the mid section of cracked member at the stabilized cracking stage. With these assumptions, a model of tension stiffening effect is proposed by accounting for the force equilibrium and strain compatibility condition associated to the steel strain and concrete contribution by bond stress. The model is applied to the test results available in literatures, and the predicted values are shown to be in good agreement with the experimentally measured behavior.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.674-682
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• 2009

The purpose of this study was to investigate the effect of aquatic gait training on plantar foot pressure, foot kinesiology and gait speed in right hemiplegic patients. The subject were 20 stroke patients who elapsed from 12 month to 24 month after stroke(aquatic gait training group(n=10), land gait training group(n=10)). This study measured plantar foot pressure, toe out angle, subtalar joint angle, gait speed from data of gate on 2m long measuring apparatus for RS-scan system(RS scan Ltd. German). This experiment performed in twice, before and after the aquatic gait training and land gait training. Collected data were statistically analyzed by SPSS Ver. 12.0 using descriptive statistics, paired t-test. Aquatic gait training group had more variety pressure area on their foot such as T1(Toe 1), HM(Heel medial), and HL(Heel lateral). But motion of subtalar joint flexibility and toe out angle decreased considerably and gate speed also increased. According to the result, aquatic gait training is considered as more effective way in foot stability and normal gait pattern than land gait training.

• The Journal of the Acoustical Society of Korea
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• v.34 no.3
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• pp.200-209
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• 2015

An underwater sound surveillance system detects and tracks enemy ships in real-time using hydrophone arrays, in which seabed-mounted sensor arrays play a pivotal role. In this paper the conceptual design of seabed-mounted, cylindrical hydrophone arrays for use in shallow coastal waters is performed via finite element calculations. To stabilize the receiving characteristics under the ocean ambient noise, a technique for whitening the ambient noise spectrum using a metal baffle is proposed. Optimization of the array configuration is performed to achieve the directivity in the vertical and azimuthal directions. And the effects of the sonar dome shape and material on the structural vibration and sound scattering properties are studied. It is demonstrated that a robust hydrophone array, having a sensitivity deviation less than 4 dB over the frequency range of interest, can be obtained through the whitening of the ambient noise, the optimization of the array configuration, and the design of acoustically transparent sonar domes.