• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.141-148
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• 2011

Support vector machines have been extensively studied and utilized in pattern recognition area for years. One of interesting applications of this technique is music/speech classification for a standardized codec such as 3GPP2 selectable mode vocoder. In this paper, we propose a novel approach that improves the speech/music classification of support vector machines. While conventional support vector machine optimization techniques apply during training phase, the proposed technique can be adopted in classification phase. In this regard, the proposed approach can be developed and employed in parallel with conventional optimizations, resulting in synergistic boost in classification performance. We first analyze the impact of kernel width parameter on the classifications made by support vector machines. From this analysis, we observe that we can fine-tune outputs of support vector machines with the kernel width parameter. To make the most of this capability, we identify strong correlation among neighboring input frames, and use this correlation information as a guide to adjusting kernel width parameter. According to the experimental results, the proposed algorithm is found to have potential for improving the performance of support vector machines.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.288-294
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• 2011

In this paper, the FPGA-based SoC board (Xilinx Virtex-4 ML401 EVM) is adopted to control electrical power inverter system. For marine application, its performance is shown on PC-based system for monitoring electrical characteristics of a power inverter using by the NMEA 2000 protocol. This power inverter system is achieved in Real-Time monitoring and control by dual micro-processor operation on embedded FPGA-based SoC board. One micro processor is for control (Control processor) electrical power inverter using by PWM signal. And the other microprocessor (Communication processor) is for communication with PC-based monitoring system. The two-processor is communicating each other using by dual-port ram (DPRAM). PC-based system user can control and monitor information of the electrical power inverter via NMEA 2000 based communication processor. Control and monitoring information includes the inverter status and configuration. SoC board converts this information to Parameter Group Numbers (PGNs) in the NMEA 2000 protocol. This system can be applied to marine power electronics for distributed power generation, transmission or regulation systems on the ship.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.13-18
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• 2011

In this paper, we have examined electrical characteristics of LDO regulator according to the process variation using a 1 ${\mu}m$ 20 V high voltage CMOS process. The electrical analysis of LDO regulator have been performed with three kind of SPICE parameter sets (Typ : typical, FF : fast, SS : slow) by process variation which cause change of SPICE parameter such as threshold voltage and effective channel length of MOS devices. From simulation results, we confirmed that in case of SS type SPICE parameter set, the LDO regulator has 3.6 mV/V line regulation, 0.4 mV/mA load regulation and 0.86 ${\mu}s$ output voltage settling time. And in case of Typ type SPICE parameter set, the LDO regulatorhas 4.2 mV/V line regulation, 0.44 mV/mA load regulation and 0.62 ${\mu}s$ output voltage settling time. Finally, in the FF type SPICE parameter set, the LDO regulator has 7.0 mV/V line regulation, 0.56 mV/mA load regulation and 0.27 ${\mu}s$ output voltage settling time.

• Journal of Advanced Navigation Technology
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• v.18 no.2
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• pp.158-164
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• 2014

For transmitting the ultra-high speed optical signals with better performance, the techniques to suppress or mitigate the signal distortion due to group velocity dispersion and optical Kerr effects are required. Dispersion management (DM), optical phase conjugation, and the combination of these two are promising techniques to compensate for the signal distortion. However, the fixed length of single mode fiber (SMF) and the fixed residual dispersion per span (RDPS) usually used in these optical links restricts flexible link configuration. The goal of this paper is to investigate the possibility of the flexible configurations of the ultra-high and long-haul optical transmission systems by using the artificial and the random distribution of SMF length and RDPS of each fiber spans consisted of the optical link. It is confirmed that the proposed link configurations should be one of the methods suitable for implementing the flexible optical transmission systems, however which depend on other link parameters, such as the averaged RDPS, and the launch power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.581-584
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• 2011

It is necessary to know what a range is effective for induction to prepare protective measures. In this paper, a simulation is practised to find ranges appropriate to underground transmission and distribution power line. There are two elements for ranges. They are parallelized length and separate distance between a telecommunication line and power line. The legal law presents limited voltages of induction. Simulation means to find what specification range of above two elements the induced voltage is over the limited voltage at. It was simulated that induced voltage for the case of underground power lines was over at the length of about 13km when the separate distance was fixed at 3m.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.7B
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• pp.907-915
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• 2001

본 논문에서는 차세대 이동통신인 IMT-2000 (하향: 1.885GHz∼2.025GHz) 주파수대역에서 동작하는 정사각형 적층구조 마이크로스트립 안테나를 설계 및 제작 측정하였다. 송/수신 주파수대역이 서로 상이한 IMT-2000 주파수대역에서 동작하도록 하기 위해 시뮬레이터를 사용하여 이중공진 안테나를 설계하였으며 최적화된 파라미터를 가지고 실제 제작 및 측정하였다. 측정된 결과는 다음과 같다. 공진주파수는 1.8475GHz, 2.2GHz에서 각각 나타났으며 대역폭은 각각 10.2%와 7.8%에 이르는 결과를 얻었다. 그리고 반사계수는 -18dB, -27dB로 나타났다. 이득은 시뮬레이터를 이용한 결과를 보면 8dB∼10dB의 높은 이득을 얻을 수 있음을 알 수가 있다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.78.1-78.1
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• 2010

Recently, as much supplied with new-renewable energy, as much invested in PV system. PV system consists of PV module, PCS and Monitering system, and also could be classified into the type and the capacity by installation method and cost etc. When various systems are installed in the field, it is needed to research for applying in the field and establish infrastructure in order to ensure stable efficiency and reliability. In this study, as the basic design of the demonstration test facility, it is designed the basic PV systems for each capacity to test each PCS. In addition, It is drew the climatic conditions such as insolation, temperature and the design parameters such as installation angle, shades for the local demonstration project and expected the generation of each PV system.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.143-145
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• 2008

본 논문에서는 산간벽지 또는 낙도와 같이 중앙계통으로부터 송 배전선을 이용한 전력공급이 어려운 약 계통(Weak grid)에 주로 사용되는 계통연계형 분산전원시스템의 설계 방법을 설명한다. Weak grid에서는 계통의 전압변동의 폭이 매우 크기 때문에 부하에 안정적으로 정전압을 공급할 수 있는 전압제어형 전압원인버터(VCVSI: Voltage-Controlled Voltage Source Inverter)를 주로 사용한다. 따라서 본 연구에서는 계통의 전압에 변동에 따른 각각의 시스템 파라미터 특성을 분석하고 이에 따른 최적의 시스템 용량의 선정방법을 제시한다.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.897-900
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• 2000

본 논문에서는 종방향 충돌경보 및 회피시스템(FCWA ; forward collision warning and avoidance)의 일환으로 가변적인 경사도를 가지는 고속도로상의 차선, 차량, 그리고 도로의 곡률을 효과적으로 검출할 수 있는 알고리듬을 제안하였다. 먼저 2D 영상좌표계에 나타나는 투영효과를 제거하기 위한 역투영(IPM; inverse perspective mapping)기법을 소개하였다. 또한 IPM과 필터로부터 차선과 차량을 효과적으로 검출할 수 있는 알고리듬을 소개하였다. 마지막으로 경사가 있는 실제도로영상에 대한 IMP의 수정된 파라미터 보정에 대한 개념 및 실제도로의 곡률 검출을 위한 기하학적 함수 추정기법을 설명하였다 실험결과 제안한 알고리듬이 실제도로영상에서 차선, 차량, 그리고 곡률의 검출에 효과적임을 확인할 수 있었다.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.115-123
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• 2003

In this paper, in order to guarantee successful operation of KSR-III TVC actuator in the presence of excessive external disturbances, a relief valve is designed as a key component of the actuator. It is shown that the relief valve can resolve the stability problems which occur due to actuator failure in the presence of excessive disturbance torques on the actuator. Six degree-of-freedom simulation shows that relief valves with low operating pressure and low LOHM parameter may be better is stability and performance of the TVC actuator system.