• Journal of the Korean Society for information Management
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• v.29 no.2
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• pp.225-246
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• 2012

This study purported to investigate the possibility of automatic descriptor assignment using the reclassification of author keywords in domestic scholarly databases. In the first stage, we selected optimal classifiers and parameters for the reclassification by comparing the characteristics of machine learning classifiers. In the next stage, learning the author keywords that were assigned to the selected articles on readings, the author keywords were automatically added to another set of relevant articles. We examined whether the author keyword reclassifications had the effect of vocabulary control just as descriptors collocate the documents on the same topic. The results showed the author keyword reclassification had the capability of the automatic descriptor assignment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.80-87
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• 2003

Network reconfiguration in distribution systems is realized by changing the status of sectiona1izing switches, and is usually done for loss minimization or load balancing in the system This parer presents an approach for loss minization in distribution systems using reactive tabu search. Tabu search attempts to determine a better solution in the manner of a greatest-descent algorithm, but it can not give any guarantee for the convergence property. Reactive tabu search can give convergence property by using reaction and escape mechanism. Therefore, it can find global optimal solution regardless of initial system configuration. To demonstrate the validity of the proposed algorithm, numerical calculations are carried out the 32 bus system models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2221-2229
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• 1998

Handoff is an important parameter for system performance and capacity analysis in CDMA cell planning. In this paper, simulation tool for analyzing the effects of soft handoff on cell planning of CDMA network is developed by studying propagation model in 1.9GHz frequency specrum, soft hadnoff algorithm given by IS-95, and several parameters for CDMA cell planning. By using the tool, soft handoff gain and effects of soft handoff on cDMA system performance and capacity are analyzed. Research results and simulation tool developed in this paper can be used for optimal CDMA cell planning for PCS and IMT-2000 in 1.9GHz frequency spectrum such as locating base station and parameter optimization.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.78-83
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• 2014

A special part such as a flow passage opening device is required to prevent the disconnection of fuel transfer in a pressurized fuel tank. To meet this requirement, the device utilizing an acceleration follow-up technique was invented. RecurDyn, a dynamic analysis tool, is introduced in this article to predict the device's performance and to determine parameters affecting it. In the analysis, it is shown that balancing weights can open the passage in accordance with fuel position.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.145-151
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• 2005

Cheju-Haenam HVDC link transmits electrical power up to 300[MW] Because of its size, HVDC system has a great potential for damping power system oscillations. This paper with the frequency control of the KEPCO HVDC system linking Haenam to Cheju island. Frequency control at Cheju island ensures that the island AC system frequency is maintained Performance are evaluated using a reduced Cheju network and a detailed model of the fm system modelled in the PST software. Transient oscillations for the 3 phase fault carried out with HVDC frequency control are well damped as the control parameters have been adjusted.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.5
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• pp.317-325
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• 2003

The vibration, which often occurred in a two inertia motor system, makes it difficult to achieve a quick response of speed and disturbance rejection. This paper provides an autonomous pole assignment technique for three kinds of speed controllers (I-P, I-PD, and State feedback) using GAs(Genetic Algorithms) for a two-inertia motor system. Firstly, the optimal parameters are chosen using GAs in view of reducing overshoot and settling time, then those are used in computing the gains of each controller. Some simulation results verify the effectiveness of the proposed design. The proposed controller is expected to be the autonomous design way for controlling a two-inertia motor system with flexible shaft.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.310-312
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• 2018

In this paper, We stduy addtional consideration and method to treat carrier frquency offset on defined system parameter & requirements in IALA G1139, previous studied consecutively. We studied the method to treat carrier frequency offset by extending length of training symbol and by differential modulation. This study will publish and argue in IALA ENAV22. We will decide a method to treat carrier frequency offset from result of IALA ENAV22.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.197-203
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• 2001

Recently, the construction of gas insulated substation(GIS)s has been increased in Korea. But, the whole quantity of the VTs which were used in GIS has been imported. Under the circumstance that $SF_6$ gas power apparatus are being developed up to 800kV rating in Korea, the development of EＨＶ　$SF_6$ gas VT is essential for localizing the power apparatus. As for EHV VT, destructive ferroresonance can be generated due to the combination of capacitiances between poles of circuit breaker, ground capacitance of bus and nonlinear excitation property of VT core. But the theoretical analysis about ferroresonance has not been fully achieved in Korea. Therefore, in this paper the authors would like to contribute for localizing EHV $SF_6$ gas VT by developing the diagram of ferroresonance zone according to the parameters of the circuit and the saturable reactor.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2381-2383
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• 1998

직류직권모터는 전동지게차와 같은 물류용 전동차에서 사용되는데, 우수한 기동 토오크를 가지는 반면에 파라미터의 열적, 변화가 심하고 마찰과 부하의 비선형성이 존재해 기존의 제어기로는 만족할 만한 성능을 내지 못한다. 본 논문에서는 이를 해결하기 위해 퍼지제어기를 사용한다. 퍼지제어기는 변수의 애매성에 바탕을 두고 제어하기 때문에 이러한 비선형성에 대해 강인하나, 소속함수의 결정과 퍼지규칙의 선정이 어려우며, 체계적인 방법이 존재하지 않는다. 이러한 퍼지제 어의 결점을 해결하기 위해 소속함수는 유전 알고리즘을 통해 자기동조 시키며 퍼지규칙은 오차와 오차변화율의 위상평면을 이용하여 결정한다. 실용성을 검증하기 위해 TI사의 DSP TMS320F240을 이용해 실시스템에 적용했으며, 이를 통해 부하의 변동 및 기준 속도의 변화에도 잘 대처함을 알 수가 있었다.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.281-287
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• 2003

This paper proposed an improvement scheme for effective usage of radio-frequency management system(RFMS), which has been operated to facilitate national spectrum management and monitoring in Korea. Based on the wave propagation models, interference analysis algorithms, and sharing criteria recommended by ITU-R, we derived criteria for the automated selection of the channel interference analysis algorithms and sharing conditions adequate to the environment to be analysed. Then using the obtained criteria, computer and program has been made and shown to select the most appropriate propagation models, interference analysis algorithms, and sharing criteria from the ones provided in RFMS, with the illustrative example.