• Proceedings of the KSR Conference
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• 2010.06a
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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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• v.6 no.4
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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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• v.6 no.3
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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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• v.28 no.3
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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.

• Proceedings of the KIEE Conference
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• 2002.04a
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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.

• Proceedings of the KIPE Conference
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• 2000.07a
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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.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.4
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• pp.65-73
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• 2003

This paper presents the implementation of an analog signal-processing ASIS to detect an angular velocity signal from a vibrator angular velocity detection sensor. The output of the sensor to be charge appeared as the variation of the capacitance value in the structure of the sensor was detected using charge amplifiers and a self oscillation circuit for driving the sensor was implemented with a sinusoidal self oscillation circuit using the resonance characteristics of the sensor. Specially an automatic gain control circuit was utilized to prevent the deterioration of self-oscillation characteristics due to the external elements such as the characteristic variation of the sensor process and the temperature variation. The angular velocity signal, amplitude-mod)Hated in the operation characteristics of the sensor, was demodulated using a synchronous detection circuit. A switching multiplication circuit was used in the synchronous detection circuit to prevent the magnitude variation of detected signal caused by the amplitude variation of the carrier signal. The ASIC was designed and implemented using 0.5${\mu}{\textrm}{m}$ CMOS process. The chip size was 1.2mm x 1mm. In the experiment under the supply voltage of 3V, the ASIC consumed the supply current of 3.6mA and noise spectrum density from dc to 50Hz was in the range of -95 dBrms/√Hz and -100 dBrms/√Hz when the ASIC, coupled with the sensor, was in normal operation.

• Journal of Power Electronics
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• v.16 no.3
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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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.