• 한국정보과학회논문지:정보통신
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• 제37권5호
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• pp.403-408
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• 2010

센서 노드는 사막, 도시, 데이터 센터등과 같이 온도의 변화가 심한 환경에 설치될 수 있다. 특히 온도가 증가하게 되면 설정한 파워에 비해 출력되는 파워가 감쇄되기 때문에 RSSI와 같은 링크 품질의 저하를 초래하며, 패킷 손실이 발생될 수 있다. 무선 환경에서 온도의 변화를 보상하기 위한 노드간에 링크 품질의 변화를 파악하고 일련의 피드백 과정을 통하여 전송파워 제어하는 기존의 방법이 있으나, 추가적인 제어 패킷들이 많이 발생하는 문제점이 있다. 본 논문에서는 이러한 온도 변화에 따른 링크품질의 유지를 위하여 T2PC(Temperature-aware Transmission Power Control)를 제안하였다. T2PC는 각 노드에서 자체적으로 얻을 수 있는 온도정보를 이용하여 전송파워를 제어함으로서 감쇄된 랭크 품질을 보상하도록 하였다. 또한 기존의 피드백을 이용한 전송파워 제어 기법보다 적은 컨트롤 패킷으로 패킷 수신율을 향상시켰다.

• 대한기계학회논문집A
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• 제20권5호
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• pp.1426-1435
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• 1996

In this paper. a network theory for generaltransmission systme was extended considering the direction of power flow. Also, a modified network model was suggested for a node with 4 shafts in order to verify the power flow. Based on the extended network theory, a simulation program was developed to analyze a hydro-mecaanical tranmission(HMT) system consistion of two hydrostatic pump motors, severeal planetary gear trains steer differential gear. The simulation result showed that the extendednotwork analysis program develped can predict the power circulation as well as the magnitude of torque and speed for each transmission element and can be used design tool for genaral power transmission system.

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.28-36
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• 2002

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.331-332
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• 2008

최근 엘리노 현상과 기상이변(태풍 및 폭설)으로 갤로핑 및 전선도약(Sleet jump) 등에 따른 송전선로 상간단락 고장의 우려가 날로 증가하고 있다. 특히 345kV급 간선계통의 상간단락 고장은 순간전압 강화 등 전기품질 저하로 이어질 수 있다. 이에 본 논문에서는 345kV 2도체용 폴리머 상간스페이서를 개발하여 상간단락고장에 대한 근본적인 예방책을 제시하였다. 폴리머용 345kV 절연 설계, 고강도 FRP ROD 설계 및 턴버클을 이용한 미세조정 장치 적용, 코로나 방지를 위한 코로나 링 채용 등을 통하여 최적의 345kV 2도체용 상간스페이서를 고안하였다. 또한 상간스페이서 소재의 성능 평가 및 해석을 위하여 Maxwell 2D Field Simulator를 이용하여 모델링하였으며 갓 형상에 따른 전계분포 해석과 FRP와 고무 계면에서의 전계분포 해석도 수행하였다.

• 한국소음진동공학회논문집
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• 제20권9호
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• pp.856-862
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• 2010

In this paper, the power flow analysis(PFA) method was developed to predict the vibrational responses of coupled co-planar orthotropic plates in frequencies ranging from medium to high. To cover the power transmission and reflection at the joint of the orthotropic plates, the wave transmission approach is applied with the assumption that all the incident waves are normal to the joint. Through numerical analyses, the power flow energy density and intensity fields of coupled co-planar orthotropic plates were compared with those of classical modal solutions by changing the frequency and internal loss factor, and they show good agreement in terms of the global decay and the attenuation patterns of the energy density.

• 유공압시스템학회논문집
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• 제6권4호
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• pp.16-23
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• 2009

The major system of an agricultural shuttle power-shift tractor is the transmission, using power-shift. Because the shifting performance depends on the hydraulic control system, the most important aspect of the optimization is the design of the hydraulic control system. This study was conducted to develop the simulation model of hydraulic control system for the shuttle power-shift transmission by using Easy5 software. Bench test was conducted to verify the simulation. Also, the design parameters which influence the pressure modulation characteristics were investigated.

• 전기학회논문지
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• 제66권12호
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• pp.1705-1711
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• 2017

This paper analyzes the impact of DRA (Demand Response Aggregator) on market power when competing with power generation companies (Gencos) in the electricity market. If congestion occurs in the transmission line, the strategic choice of the power generation company increases exercise of market power. DRA's strategic reduction of power load impacts the strategy of Gencos, which in turn affects the outcome of the load reduction. As the strategy of Gencos changes according to the location of the congested transmission line, the impact on the market depends on the relative location of the congested line and the DRA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.430-432
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• 2004

The standard power system model is needed to test a transmission line protective relay There are two methods to develop a power system model for transmission line protection. First method is based on characteristic power system model, and second method is based on functional power system model. This paper presents a standard power system model for performance test of transmission line protective relay, where the power system model is based on the two methods. And this model is simulated by using RTDS to test a protective relay.

• Journal of electromagnetic engineering and science
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• 제19권1호
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• pp.42-47
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• 2019

This paper introduces a modified Wilkinson power divider that uses uniform transmission lines for various terminated impedances and an arbitrary power ratio. For the designed power ratio, the proposed divider changes only the electrical lengths of the transmission lines between the input and output ports, and those between the output ports and the isolation resistor. In this case, even when various termination impedances of the ports exist, the divider characteristics are satisfied. To verify the feasibility of the proposed divider, two circuits were designed to operate at a frequency of 2 GHz with 2:1 and 4:1 power splitting ratios and various terminated impedances of 40, 70, and $60{\Omega}$ for one circuit, and 50, 70, and $60{\Omega}$ for the other. The measurement and simulation results were in good agreement.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.283-287
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• 2003

A new method to miniaturize ${\lambda}/4$ transmission line of power divider is proposed. The method utilizes simple combination of the shorted coupled-line pair instead of the transmission line with very high impedance and shunt lumped capacitors. The length of ${\lambda}/4$ transmission line of power divider is about 16% over the conventional power divider at 1 GHz.