• Journal of Magnetics
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• 제19권3호
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• pp.273-281
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• 2014

This paper presents an innovative design for a low-speed, direct-drive, axial-flux permanent-magnet (AFPM) generator with a coreless stator and rotor that is intended for application to small wind turbine power generation systems. The performance of the generator is evaluated and optimized by means of comprehensive 3D electromagnetic finite element analysis. The main focus of this study is to improve the power output and efficiency of wind power generation by investigating the electromagnetic and structural features of a coreless AFPM generator. The design is validated by comparing the performance achieved with a prototype. The results of our comparison demonstrate that the proposed generator has a number of advantages such as a simpler structure, higher efficiency over a wide range of operating speeds, higher energy yield, lighter weight and better power utilization than conventional machines. It would be possible to manufacture low-cost, axial-flux permanent-magnet generators by further developing the proposed design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.188-190
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• 2008

In this paper, it proposes a the high efficiency tracking system regarding power loss when operating a tracking system for environment variable such as a rapidly changing insolation to improve the power of PV tracking system. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this paper proposes a nonel control algorithm of the tracking system. The paper is analyzed efficiency about conventional PV tracking method, comparing proposed algorithm with high performance method. We show propriety of proposed algorithm by means of the demonstrable study.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.403-406
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• 2008

In this paper proposes a novel tracking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV tracking system. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this paper proposes a nonel control algorithm of the tracking system. The paper is analyzed efficiency about conventional PV tracking method, comparing proposed algorithm with high performance method. We show propriety of proposed algorithm by means of the demonstrable study.

• Journal of Contemporary Eastern Asia
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• 제17권1호
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• pp.27-49
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• 2018

Public Diplomacy (PD) is the third pillar of South Korean foreign policy. According to the Ministry of Foreign Affairs, PD aims to attract foreign audiences by means of art, knowledge transmission, media, language and foreign aid. When it comes to the Korean language, its global profile has seen an especially marked increase in recent years (Kim, 2009). Thus, this paper's objective is to explain the relevance of the Korean language in the generation of South Korea's soft power. I draw from $C{\acute{e}}sar$ Villanueva's reflections in order to problematize how language promotion can be translated into soft power at five different levels: the empathetic, the sympathetic, the geopolitical, the diplomatic and the utilitarian. I observe that in the case of the Korean language in Mexico City, soft power has the potential to be generated on three levels: it helps to increase knowledge of Korean culture (empathetic); it exercises symbolic persuasion (geopolitical), since the products of cultural industries are mostly in Korean; and it is used as a tool for economic transactions in Mexico City (utilitarian).

• 대한기계학회논문집B
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• 제28권12호
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• pp.1582-1590
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• 2004

The purpose of this study is to show the existence of optimal operation conditions for minimum fuel consumption of the gas turbine based combined cycle cogeneration power plant. Optimal operational condition means the optimal distribution of the power generated by each gas turbine and the heat generated by each HRSG. Total fuel consumption is calculated by the sum of the fuels for gas turbines and supplementary boiler. Fuel consumption is calculated by numerical methods of energy equations which contain the power generated from gas and steam turbines, the heat generated by HRSG and the heat extracted from high pressure steam turbine.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.598-602
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• 2002

This paper presents the 3-phase hybrid series active power filter with dynamic voltage restorer(DVR) which serve as an energy buffer and current harmonics blocking resistor connected to sensitive loads, such as, to compensate voltage dips and current harmonics in power distribution system. The DVR is to inject a dynamically controlled voltage generated by a forced commutated converter in series to the bus voltage by means of a booster transformer. The momentary amplitudes of the three injected phase voltages are controlled such as to eliminate any detrimental effects of a bus fault to the load voltage. The proposed system is able to simultaneously compensate current harmonics, voltage fluctuating and voltage unbalance in power distribution systems. The reference phase angle detected by synchronized with the positive sequence component of the unbalanced source by using symmetrical component transformation. The effectiveness of proposed system is verified by the computer simulation.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.1-5
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• 2014

When renewable sources are connected to the distribution network in the form of a distributed generators(DGs), the effect of intermittent output appears as voltage fluctuation. The surplus power at the consumer ends results in the reverse power flow to the distribution network. This reverse power flow causes several problems to the distribution network such as overvoltage. Application of the reactive power control equipment and power flow control by means of BTB inverter have been suggested as the general solutions to overcome the overvoltage, but they are not economically feasible since they require high cost devices. Herein, we suggest the feeder loop line switch control method to solve the problem.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.591-593
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• 2007

This paper is to cluster the AMR (Automatic Meter Reading) data. The load survey system has been applied to record the power consumption of sampling the contract assortment in KEPRI AMR. The effect of the contract assortment change to the customer power consumption is determined by executing the clustering on the load survey results. We can supply the power to customer according to usage to the analysis cluster. The Korea a class of the electricity supply type is less than other country. Because of the Korea electricity markets exists one electricity provider. Need to further divide of electricity supply type for more efficient supply. We are found pattern that is different from supplied type to customer. Out experiment use the Clementine which data mining tools.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.775-777
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• 1997

This paper presents an algorithm for the calculation of LSC(Load Supplying Capability) in composite power systems. LSC means the maximum load which the composite power system can supply under the constraints of interest and power flow equations. In this paper, Successive Linear Programming algorithm is used to calculate the LSC of composite power systems. This algorithm is applied to the Six-Bus system and IEEE RTS.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.55-58
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• 2014

The next-generation AlGaN/GaN HEMT power devices need higher power at higher frequencies. To know the device characteristics, the simulation of those devices are made. This paper presents a simulation study on the DC and RF characteristics of AlGaN/GaN HEMT power devices. According to the reduction of gate length from $2.0{\mu}m$ to $0.1{\mu}m$, the simulation results show that the drain current at zero gate voltage increases, the gate capacitance decreases, and the maximum transconductance increases, and thus the cutoff frequency and the maximum oscillation frequency increase. The maximum oscillation frequency maintains higher than the cutoff frequency, which means that the devices are useful for power devices at very high frequencies.