• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1100-1105
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• 2010

The high speed line and conventional line are a single-phase AC feeding system; and power supplies of different phases meet at SS(SubStation)s or SP(Sectioning Post)s. These sections should be negotiated with the main circuit breaker in the traction vehicle switched off, whereby the length of the neutral zone prevents the pantographs shunting adjacent overhead line section. In order for electric railway vehicles to make power running there, there must be a power supply changeover section (approx. for 1km), where a changeover switch changes a power supply to the other power supply of a train running direction sequentially. For a thorough changeover switching control, the precise train position detection is necessarily required. In this paper, to realize the ground-based train position detection method, configuration scheme of train position detection equipment is suggested by using track circuit and axle counter.

• Journal of information and communication convergence engineering
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• 제6권4호
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• pp.439-443
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• 2008

It is shown that even if the modulating frequency of the light is too high for direct detection the signal can be extracted by frequency conversion at the same time as the detection by means of the nonlinearity of the APD. When this frequency conversion detection is applied to an optical receiver, the detection bandwidth can be increased while the configuration of the optical detection circuit and the signal processing in the subsequent stages are simplified. A fundamental analysis is carried out with an APD which is confirmed experimentally.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.270-274
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• 2008

This paper proposes an advanced signal processing circuit for a fingerprint sensor based on ridge resistivity. A novel fingerprint integrated sensor using ridge resistivity variation resulting from ridges and valleys on the fingertip is presented. The pixel level simple detection circuit converts from a small and variable sensing current to binary voltage out effectively. The sensor circuit blocks were designed and simulated in a standard CMOS 0.35 ${\mu}m$ process.

• ETRI Journal
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• 제28권3호
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• pp.355-363
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• 2006

This paper presents a low-cost RF parameter estimation technique using a new RF built-in self-test (BIST) circuit and efficient DC measurement for 4.5 to 5.5 GHz low noise amplifiers (LNAs). The BIST circuit measures gain, noise figure, input impedance, and input return loss for an LNA. The BIST circuit is designed using $0.18\;{\mu}m$ SiGe technology. The test technique utilizes input impedance matching and output DC voltage measurements. The technique is simple and inexpensive.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.183-185
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• 2002

This paper proposes the test method for the testing of a RLC parallel circuit on the electronic circuit board. This method utilizes a guarding circuit and a phase detection circuit. The guarding circuit separates electrically the tested device or circuit from printed circuit board. Phase detector estimates the phase difference from two signals, voltage and current. This method computes R. L and C value from phase difference($\theta$) and impedance value(Z) obtained by enforcing two other frequence stimulus under the guarding state.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.172-176
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• 2000

The paper presents the fault detection and isolation of two DC-DC converters parallel operation by ZCT method. Two experimental prototype converters were designed and implemented for evaluation of fault tolerant system. The experimental results show that fault detection and isolation circuit works very well.

• 대한전자공학회논문지SD
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• 제40권4호
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• pp.65-73
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• 2003

본 논문은 진동형 각속도 검출 센서로부터 각속도 신호를 검출하는 애널로그 신호처리 ASIC의 구현에 관한 것이다. 각속도 검출 센서의 출력은 구조적으로 콘덴서의 용량변화로 나타나므로 이를 검출하기 위하여 전하 증폭기를 이용하였으며, 센서의 구동에 필요한 자체발진회로는 각속도 검출 센서의 공진 특성을 이용한 정현파 발진회로로 구현하였다. 특히 센서의 제조 공정으로 인한 특성 변화나 온도 변화와 같은 외부 요인에 의한 자체발진특성의 열화를 방지하기 위하여 자동이득조절회로를 사용하였다. 진동형 각속도 검출 센서의 동작특성에 의하여 진폭변조 형태로 나타나는 각속도 신호를 검출하기 위하여 동기검파회로를 사용하였다. 동기검파회로에서는 반송파의 크기에 따라 검파신호의 크기가 달라지는 현상을 방지하기 위하여 스위칭 방식의 곱셈회로를 사용하였다. 설계된 칩은 0.5㎛ CMOS 공정으로 구현하였으며, 1.2㎜×1㎜의 칩 크기로 제작되었다. 실험 결과 3V의 전원전압에서 3.6mA의 전류를 소비하였으며, 칩과 각속도 센서를 결합한 정상동작상태에서 직류에서 50㎐까지 잡음 스펙트럼 밀도는 -95 dBrms/√㎐에서 -100 dBrms/√㎐ 사이에 존재하였다.

• Journal of Power Electronics
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• 제16권3호
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• pp.1097-1109
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• 2016

Fault detection and isolation are related to system monitoring, identifying when a fault has occurred, and determining the type of fault and its location. Fault detection is utilized to determine whether a problem has occurred within a certain channel or area of operation. Fault detection and diagnosis have become increasingly important for many technical processes in the development of safe and efficient advanced systems for supervision. This paper presents an integrated technique for fault diagnosis and classification for open- and short-circuit faults in three-phase inverter circuits. Discrete wavelet transform and principal component analysis are utilized to detect the discontinuity in currents caused by a fault. The features of fault diagnosis are then extracted. A fault dictionary is used to acquire details about transistor faults and the corresponding fault identification. Fault classification is performed with a fuzzy logic system and relevance vector machine (RVM). The proposed model is incorporated with a set of optimization techniques, namely, evolutionary particle swarm optimization (EPSO) and cuckoo search optimization (CSO), to improve fault detection. The combination of optimization techniques with classification techniques is analyzed. Experimental results confirm that the combination of CSO with RVM yields better results than the combinations of CSO with fuzzy logic system, EPSO with RVM, and EPSO with fuzzy logic system.

• 전기학회논문지
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• 제60권8호
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• pp.1617-1621
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• 2011

In this paper, in order to reduce the electrical disaster such as electrical fire at traditional markets, we need to develop the circuit breaker which is able to monitor the power status of electrical equipments. Therefore, for solving the those problems, we developed the detection censor(ZCT, CT) and equipment of data analysis and transmission. The detection censor and equipment is able to monitor the electrical equipments condition(over current, leakage current, arc, etc.). We constructed Test-Bed for testing reliability of the circuit breaker and obtained certification. And we tested the over current, leakage current and arc under the normal condition. This paper will be used to the data for development an cabinet panel which is able to monitor the actual loads.

• 전력전자학회논문지
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• 제18권2호
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• pp.199-204
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• 2013

Recently, the demand for fuel efficient electric vehicles (EVs) and hybrid electric vehicles (HEVs) has been growing globally. Due to the increased number of switching devices in the electrified vehicles, the probability of the semiconductor device failure is much higher than in other application areas. A sudden failure in one of the power switches and insufficient power management ability in the systems not only decreases system performance, but also leads to critical safety problems. In this paper, novel switch open circuit fault detection method is proposed, and the proposed approach is verified by experiments.