• Journal of the Optical Society of Korea
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• v.8 no.4
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• pp.149-155
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• 2004

Newly developed modal transmission-line theory(MTLT) is used to analyze rigorously the optical power distribution in grating-assisted directional couplers(GADCs) with three guiding channels. By defining a novel coupling efficiency ${\eta}$ amenable to the rigorous analytical solutions of modal transmission-line theory, we explicitly evaluate the power coupling and distribution of TM modes. The results reveal that the incident power is sensitively partitioned through three output channels in terms of such grating parameters as the grating period, the duty cycle, and the operating wavelength.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.29-30
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• 2016

This paper describes a distributed static series compensator (DSSC) which is a type of distributed flexible ac transmission system (DFACTS). The control principles including the power flow control and the current regulation are explained in detail. In order to verify the effectiveness of the DSSC, the simulation results are offered.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1453-1456
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• 2004

PARO, a power-aware routing optimization mechanism, is proposed in [1] to minimize the transmission power needed to forward packets between wireless devices in ad hoc network. The mechanism works by redirecting the route to pass through one or more intermediate nodes on behalf on source-destination pairs, then reducing the end-to-end transmission power. This paper will show an extension of this model and provide an analysis of the geometrical area lying between source and destination in which the intermediate node elects to perform redirection. The duration the intermediate node stays in that area is also computed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.646-655
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• 2015

The purpose of this study was to evaluate the perceived distance from home to high-voltage power lines using a transmission and substation geographic information system(TGIS). Of the 725, 136 respondents reported that high voltage power transmission tower, power lines or substation was within visual field range from home. Among them, 114 respondents reported valid address, which could be used in the analysis of TGIS. Forty two respondents(36.8 %) estimated that the power lines were closer and 15 respondents(13.2 %) estimated that they were farther than they actually were. Our current findings suggest that the reported distance from home to high-voltage power transmission towers, power lines, and substations cannot be used as a proxy for exposure to electromagnetic fields due to the low validity.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.60-65
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• 2016

Dynamic performance of transmission has a substantial effect on dynamic performance and fuel efficiency of a vehicles. Dynamic performance of transmission and mass moments of inertia of transmission gears are related directly each other. Then a smaller amount of kinetic energy from vehicles that repeat acceleration and deceleration requires lighter rotating part in transmission. It is going to increases fuel efficiency as a result. In this study, equivalent inertia moments of inertia at different speeds were calculated by simplifying the transmission system. To find out lightening effect at low speed level gear on fuel efficiency, the powerflow of transmission was analyzed. And the lightning effect of the rotating parts in transmission is compared with the mass reduction of sprung parts in vehicle.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.48-56
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• 2016

In this paper, we analyze the power flow of an eight-speed automatic transmission by using a lever analogy for the manufacturing of planetary gears. The results indicate that the engine power is passed down to the carrier and ring gear in the first double pinion planetary gear (DPPG1), and to the sun gear, carrier, and ring gear in DPPG3 for the first speed. Although the power flow is similar in the second speed, the power circulation occurs in the second single pinion planetary gear (SPPG2). For the third speed, the engine power is passed from the carrier to the ring gear in DPPG, at which point the power is split between the sun gears of SPPG2 and DPPG3.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.98-101
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• 2007

A fully integrated 5-GHz CMOS power amplifier for IEEE 802.11a WLAN applications is implemented using $0.18-{\mu}m$ CMOS technology. An on-chip transmission-line transformer is used for output matching network and voltage combining. Input balun, inter-stage matching components, output transmission line transformer and RF chokes are fully integrated in the designed amplifier so that no external components are required. The power amplifier occupies a total area of $1.7mm{\times}1.2mm$. At a 3.3-V supply voltage, the amplifier exhibits a 22.6-dBm output 1-dB compression point, 23.8-dBm saturated output power, 25-dB power gain. The measured power added efficiency (PAE) is 20.1 % at max. peak, 18.8% at P1dB. When 54 Mbps/64 QAM OFDM signal is applied, the PA delivers 12dBm of average power at the EVM of -25dB.

• 전기의세계
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• v.18 no.1
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• pp.24-29
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• 1969

This is preliminary study concerning the future construction and operation of 345KV power transmission line in Korea which will be added to the existing 161KV power system by the end of 1970 in order to increase the power carrying capacity between Seoul and Pusan area; 350 kilo meters aparts, in accordance with the ambitious second five years power development schedule of Korea Electric Company. The result of this study says that an intermidiate switching station should be installed at the middle position of the line to improve the transient stability of the system, considerable amount of capacitors or synchronous condenser are to be installed to reduce the voltage drop at receving end of line during the heavy load hours, and also in some measure to avoid the voltage rise by self-excitation of power generators during the light load hours and while energizing the line. This is the first attempt to realize the EHV power transmission line in Korea so that the additional study is necessary on the kind and size of conductors, the necessary number of insulators and the suitable clearance distances between conductor and steel tower or earth from the technical and economical view points. These are necessary steps to be taken by the writer before getting into the calculation on the transient stablity of the power system.

• Journal of Magnetics
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• v.22 no.1
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• pp.43-48
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• 2017

In order to detect the current flowing through concealed conductor, this paper proposes a new method based on derivative method. Firstly, this paper analyzes the main peak characteristic of the derivative function of magnetic field generated by a current-carrying conductor, and a relationship between the current flowing through the conductor and the main peak of the derivative function is obtained and applied to calculate the current. Then, the method is applied to detect the conductor current flowing through grounding grids of substations. Finally, the numerical experimental and field experiment verified the feasibility and accuracy of the method, and the computing results show that the method can effectively measure the conductor current of grounding grids with low error, and the error is within 5 %.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.185-185
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• 2020