• 전력전자학회논문지
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• 제11권6호
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• pp.535-542
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• 2006

저궤도 인공위성 전력계 시스템의 설계 및 해석을 위한 태양전지 전력조절기의 대신호 안정도해석을 수행한다. 태양전지 전력조절기에서 제어가능한 모든 방법에 따른 태양전지에서 바라본 태양전지 전력조절기의 부하특성을 분류하고, 상태공간해석을 이용하여 태양전지 시스템의 대신호적 안정도를 해석한다. 또한, 본 논문에서는 태양전지 전력조절기의 부하특성을 정전력부하에서 정저항부하로 변환하여 대신호적인 안정도를 확보하는 비선형변환을 제안한다. 제안된 변환기법을 통해 최대전력점 추적제어나 배터리 충전제어 및 전류분배제어가 가능한 병렬 모듈 태양전지 레귤레이터에 적합한 단일 전류 제어기를 구성한다. 제안된 대신호 해석과 저항제어를 검증하기위해, 200W급 태양전지와 100W급 태양전지 전력조절기 두 모듈을 병렬로 구성하여 실험하였다.

• 전기학회논문지
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• 제65권10호
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• pp.1672-1681
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• 2016

This paper proposes a wireless parallel operation method of three-phase modular UPS inverter using resistive droop control. Furthermore, it applies a virtual resistor to droop control so that the output impedance of UPS inverter gets closer to resistive. It makes resistive droop control effective. The simulation using PSIM was performed in order to verify the validity of proposed algorithm. After consisting two-parallel system with three-phase modular UPS inverter, the experiment according to resistive load was conducted. It demonstrated the performance of current sharing and power sharing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1704-1708
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• 2008

Many studies have emphasized the importance of resistive exercise to maintain a healthy human body, particular in prevention of weakening of physical strength. Recently, some studies advocated that an application of vibration as a supplementary means in a regular training was effective in encouraging physical strength. Aim of the current study was, therefore, to identify if an application of vibration in a resistive exercise was effective in encouraging physical strength as that in a regular training. A 3-dimensional virtual lower extremity model for a healthy male and virtual leg-press model were generated and synchronized. Dynamic leg-press exercises on a slide machine with/without extra load and on a footboard with vibration as well as on a slide machine with extra load were analyzed. The results of the current indicated that the application of the vibration on the dynamic leg-press exercise might be not greatly effective in encouraging physical strength, compared with the dynamic leg press exercise with extra load. It was, however, thought that the application of the vibration might be helpful to elderly individuals because the reduced maximum muscle strength appeared by the effect of the vibration may avoid a muscular spasm, which can be driven from a high muscle strength sometimes produced during the leg-press exercise with extra load.

• 대한전자공학회논문지
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• 제8권3호
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• pp.15-26
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• 1971

본논문은 트란지스터발진기의 발진영역과 부저항의 변화에 대하여 하나의 새로운 방법을 써서 고찰한 것이다. 트란지스터귀환발진기의 발진영역을, 귀환소자임피이던스의 복소평면상에 나타내면 원이 된다. 그리고, 귀환소자임퍼이던스의 저항분을 일정하게 하고, 리액턴스분을 변화시키거나, 혹은 이와 반대로 리액틴스분을 일정하게하고, 저항분을 변화시킬 때, 출력콘덕턴스가 극소로 되는 점의 궤적은 쌍곡선이 된다. 트란지스터수정발진기에서는, 발진영역은 부하임퍼이던스의 복소평면상에서, 입력임피이던스의 실수부 및 허수부를 0이 되게 하는, 두개의 원에 의하여 정해진다. 그리고, 부하임피이던스의 저항분을 일정하게 하고 리액턴스분을 변화시키거나, 혹은 반대로 리액턴스분을 일정하게 하고 저항분을 변화시킬 때, 입력저항을 극대 또는 극소로 되게 한는 점의 궤적은, 네 개의 직선이 된다.

• 조명전기설비학회논문지
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• 제28권6호
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• pp.113-121
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• 2014

At the end of the 19th century, a battle known as the War of the Currents was fought over how electricity would be generated, delivered, and utilized. In this day and age, there has been a growing interest in Green Growth policies as countermeasures against global warming. As a result of these policies, the use of new and renewable energy needed a power converter to replace fossil fuels has expanded. To reduce power consumption through high efficiency of conversion, Low Voltage DC (LVDC) distribution systems are suggested as an alternative. In a DC distribution system, DC loads are very efficient due to decrease the stages of power conversion. If the LVDC distribution system is adopted, not only DC load but also existing AC loads should be connected with LVDC system. Thus, the modeling of two loads is needed to analyze the DC distribution system. This paper, especially, is focused on the modeling of resistive load and electronic load including power electronic converters using ElectroMagnetic Transient Program (EMTP) software.

• Architectural research
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• 제10권1호
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• pp.1-11
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• 2008

A Steel column with damaged spray-applied fire resistive material (SFRM) may exhibit reduced structural performance due to the effects of elevated temperature during fire events. Thus, the fire load behavior of steel columns with removed or reduced SFRM needs to be examined to predict the structural damage by fire. FEM analyses were performed for the flange thinning removal models in which the SFRM was reduced as a constant strip in thickness at the top flange of the column. The temperature results for all models obtained from the heat transfer analyses were included as an initial condition in the FEM structural analyses. In this study, the results of analysis show that even small remnants of SFRM led to an effective reduction of temperature at any given fire duration, and improved significantly the axial load capacity of a column as compared to the complete removal cases of SFRM.

• 한국구조물진단유지관리공학회 논문집
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• 제26권5호
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• pp.151-160
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• 2022

최근 폭발사고의 빈도수가 증가함에 따라 주요 구조부재의 손상을 저감시킬 수 있는 방호 구조물 설계에 대한 관심이 높아지고 있다. 그러나, 방호 구조물의 방호성능에 대한 국내 연구는 아직 미진한 실정이며, 아직 설계 가이드라인도 충분히 갖추어지지 못한 실정이다. 따라서, 본 연구에서는 FRP 시트 보강유무를 변수로 하여 RC 방호벽에 대한 해석적 연구를 수행하였다. 해석은 LS-DYNA 프로그램을 활용하여 수행되었으며, 해석을 통해 RC 방호벽과 FRP 시트로 보강된 RC 방호벽의 변위-시간이력곡선, 압력-충격량 도표, 취약도 곡선을 도출하였다. FRP 시트 보강방법은 RC 방호벽의 방호성능을 향상시키는데 매우 효율적인 것으로 나타났다. 또한, 폭발하중의 크기가 클수록 RC 방호벽에 대한 FRP 시트의 보강효과는 높아지는 것으로 나타났다.

• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.97-102
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• 2020

This paper presents the basic research for the design and fabrication of a 3D-printed load cell made of NCPC (nano-carbon piezo-resistive composite). We designed a structure that can resonate at a low frequency range of about 5-6 Hz with ANSYS using sensitivity analysis and a response surface method. The design was verified by fabricating the device with a low-quality commercial 3D printer and ABS filament. We conducted a feasibility test for a commercial sensor using 1000 cyclic load tests at 0.3 Hz in a material testing system. A manufacturing process for the 3D printer filament based on the NCPC was also developed using the nano-composite process.

• 식품보건융합연구
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• 제5권4호
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• pp.19-23
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• 2019

In recent years, the Internet was a lot of information on the use of Tesla coils bifilar [1] in conjunction with induction cooker, for "free" electricity during power resistive load, including different incandescent lamps. With the development of scientific and technological progress, the demand for electricity in each year is increasing, and at the same time, the need to increase the capacity of electricity production, which entails large investments and, consequently, increase of prices for consumers. As before today, the search for free electric energy is an up-to-date and still open topic. The purpose of research - simplification of information on the possibility of using bifilar coils as an electric current source in conjunction with induction cooker. Consequently, it can be concluded from the above that the use of Tesla coils in combination with induction cooker has very low k.k.d. and it is not possible to obtain excessive electric energy using the Tesla coil under the connection schemes considered.

• Advances in Computational Design
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• 제1권2호
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• pp.155-173
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• 2016

This paper presents a method of design for the energy harvesting of a piezoelectric cantilever beam. Vibration modes have strain nodes where the strain distribution changes in the direction of the beam length. Covering the strain nodes of the vibration modes with continuous electrodes effects a cancellation of the voltages outputs. The use of segmented electrodes avoids cancellations of the voltage for multi-mode vibration. The resistive load affects the voltage and generated power. The optimum resistive load is considered for segmented and continuous electrodes, and then the power output is verified. One of the effective parameters on energy harvesting performance is the existence of concentrated mass. This topic is studied in this paper. Resonance and off-resonance cases are considered for the harvester. In this paper, both theoretical and experimental methods are used for satisfactory results.