• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.24-33
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• 2009

The transition of auxiliary lines for transmitting coding information has been one of the major obstacles to restricting the scalability of Sequence Switch Coding (SSC) algorithms. A new design of SSC which does not use auxiliary lines is presented in this paper. The new design makes overhead transitions far less than the previous designs that use auxiliary lines. By applying the new technique, more than 50% of overhead transitions have been reduced, leading to the increase of 30% of the overall efficiency of SSC algorithm.

• Information and Communications Magazine
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• v.25 no.12
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• pp.10-18
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• 2008

In this paper, we present a low-power design of H.264 codec based on dedicated hardware and software solution on EMP(ETRI Multi-core platform). The dedicated hardware scheme has reducing computation using motion estimation skip and reducing memory access for motion estimation. The design reduces data transfer load to 66% compared to conventional method. The gate count of H.264 encoder and the performance is about 455k and 43Mhz@30fps with D1(720x480) for H.264 encoder. The software solution is with ASIP(Application Specific Instruction Processor) that it is SIMD(Single Instruction Multiple Data), Dual Issue VLIW(Very Long Instruction Word) core, specified register file for SIMD, internal memory and data memory access for memory controller, 6 step pipeline, and 32 bits bus width. Performance and gate count is 400MHz@30fps with CIF(Common Intermediated format) and about 100k per core for H.264 decoder.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.12
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• pp.601-608
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• 2001

The ever increasing density of adjustable speed drives(ASD) device with non-linear operating characteristics has been to put tremendous harmonic stress on end user's electrical application. All ASD controllers which employ solid state power devices cause harmonic currents in the source side line. This paper describes harmonic problems for use of ASD. In order to investigate the effect of harmonics caused by using of nonlinear load at the low voltage system, we fixed up simple load model and measured the voltage and current waveforms. Measurement results show that additional operation of linear load at the parallel bus with nonlinear load such as ASD is helpful to the reduction of harmonic influence.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.1
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• pp.79-87
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• 2000

본 논문은 저 도전 손실을 갖는 새로운 단단, 단일 스위치 역률보상 부스트형 교류/직류 변환기를 소개한다. 제안한 변환기는 약간의 구조적 차이점을 제외하고 기존의 변환기와 동일하게 해석될 수 있다. 먼저, 제안한 변환기와 기존의 변환기의 동작원리를 파악하여 두 변환기의 차이점을 이해하고 1단 역률 보상 교류/직류 변환기의 구조적 문제점인 에너지 저장 커패시터에서의 직류 전압 상승을 방지하기 위한 직류 부스 전압 궤환 방식을 도입하여 제안한 변환기에 적용하였다. 100W급 변환기를 제작/실험하여 본 변환기의 타당성을 검증하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.8
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• pp.441-448
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• 2002

Harmonics studies have been an important aspect of power conversion system analysis and design in recent years. Harmonics using power conversion device, have a harmful effect on power qualify. Nonlinear load such as converter causes harmonic and effects self & other system. There are linear and nonlinear loads in the end-user application. For filter design to reduce harmonics, it is important to understand how loads interact with each other. In this paper, effects on the power conversion system at the low voltage local bus are discussed.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.5
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• pp.573-580
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• 2014

The electrical reliability of the power generation and distribution system of Floating Liquefied Natural Gas vessels has been analyzed according to the operating modes using Electrical Transient Analysis Program in this paper. Electricity is used for the topside processes, cargo pumps for off-loading, thrusters for heading control and marine equipment. It is very important to improve the safety, efficiency, and stability of the electrical power system for successful operation. The voltage variation of the high and the low voltage bus shall be within the primitive limitation range at normal operation loads both in steady state and in the transient state. The power system was simulated and compared with class rule for design verification.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.281-286
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• 1998

This paper proposes a new single-stage, single-switch AC/DC converter based on the boost power factor correction (PFC) cell. The converter offers both high power factor and high efficiency. To reduce the dc voltage on the energy storage capacitor, the dc bus voltage feedback method was used. A 100W (5V/20A) prototype was built and tested to show the validity of the proposed converter.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.566-574
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• 2000

This paper propose a heuristic algorithm based on the Branch-Exchange (BE) method to solve Optimal feeder Routing(OFR) problem for the distribution system planning. The cost function of the OFR problem is consisted of the investment cost representing the feeder installation and the system operation cost representing the system power loss. We propose a properly designed heuristic strategy, which can handle the horizon-year expansion planning problem of power distribution network. We also used the loop selection method which can define the maximum loss reduction in the network to reduce calculation time, and proposed a new index of power loss which is designed to estimate the power loss reduction in the BE. The proposed index, can be considered with both sides, the low voltage side and voltage side branch connected with tie one. The performances of the proposed algorithms and loss index were shown with 32, 69 example bus system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.543-550
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• 2008

This paper proposes an voltage and reactive power control methodology, which is motivated towards implementation in the korea power system. The main voltage control devices are capacitor banks, reactor banks and LTC transformers. Effects of control devices are evaluated by local subsystem's cost computations. This local subsystem is decided by 'Tier' and 'Electrical distance' in the whole system. The control objective at present is to keep the voltage profile within constraints with minimum switching cost. A robust control strategy is proposed to make the control feasible and optimal for a set of power-flow cases that may occur important event from system. This studies conducted for IEEE 39-bus low and high voltage contingency cases indicate that the proposed control methodology is much more effective than PSS/E simulation tool in deciding switching of capacitor and reactor banks.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.326-328
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• 1998

This paper presents an optimal fuzzy power system stabilizer to damp out low frequency oscillation. The fuzzy logic controllers has been applied to a power system stabilizing controllers. But the design of a fuzzy logic power system stabilizer relies on empirical and heuristic knowledge of human experts as well as many trial-and-errors in general. This paper presents the optimal design method of the fuzzy logic stabilizer using the genetic algorithm, which is the optimization method based on the mechanics of natural selection and natural genetics. The proposed method tunes the parameters of the fuzzy logic stabilizer in order to minimize the consuming time during the design process. In this paper, the proposed method tunes the shape of membership function of the fuzzy variables. The proposed system is applied to the one-machine infinite-bus model of a power system. Through the case study, the efficiency of the fuzzy stabilizing controller tuned by genetic algorithm is verified.