• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.79.6-79
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• 2002

We propose here sequential 2 methods for obtain information of current or potential data for power transmission line. One is a digital data transmission unit, this is, an output of a current sensor of power transmission line is digitalized by use of an easy asynchronous protocol. The unit has high speed transform rate, easy making header caused of consisting of only logic circuit. The other is, the output of the unit is transformed via LAN interface and displayed on a personal computer. We have confirmed remote measuring using the method for 100A and 240 A of the current information of power transmission line. Therefore we will be able to see a current waveform by use of internet at a cheep c...

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.399-405
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• 2015

In this work we use the mode decomposition technique employing chirplet transform, which is able to separate the individual modes from dispersive and multimodal waveform measured with the magnetostrictive sensor. The mode decomposition technique is also used to estimate the time-frequency centers and individual energies of the reflection, which would be used to locate and characterize axial defects. The arrival times of the separated modes are calculated and the axial defect lengths can be evaluated by using the estimated arrival time. Results from an experiment on a carbon steel pipe are presented and it is shown that the accurate and quantitative defect characterization could become enabled using the proposed technique.

• Smart Structures and Systems
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• v.11 no.2
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• pp.185-197
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• 2013

We developed a simultaneous strain measurement and damage detection technique using a pair of surface-mounted piezoelectric transducers and a fiber connecting them. This is a novel sensor configuration of the fiber acoustic wave (FAW) piezoelectric transducer. In this study, lead-zirconate-titanate (PZT) transducers are installed conventionally on a plate's surface, which is a technique used in many structural health monitoring studies. However, our PZTs are also connected with an optical fiber. A FAW and Lamb wave are simultaneously guided in the optical fiber and the structure, respectively. The dependency of the time-of-flight of the FAW on the applied strain is quantified for strain sensing. In our experimental results, the FAW exhibited excellent linear behavior and no hysteresis with respect to the change in strain. On the other hand, the well-known damage detection function of the surface-mounted PZT transducers was still available by monitoring the waveform change in the conventional Lamb wave ultrasonic path.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.274-277
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• 1999

This paper is concerned with estimating the mass of a loose part in the steam generator of a nuclear power plant. Although there is the basic principle known as “Hertz Theory”for estimating mass and energy of a spherical part impacted on an infinite flat plate, the theory is not directly applicable because real plants do not comply with the underlying ideal assumptions. (Say, the steam generator is of a cylindrical and hemisphere shape.) In this work, a practical method is developed based on the basic theory and considering amplitude and energy attenuation effects. Actually, the impact waves propagating along the plate to the sensor locations become significantly different in shape and frequency spectrum from the original waveform due to the plate and surrounding conditions, distance attenuation and damping loss. To show the validity of the present mass estimation algorithm, it has been applied to the mock-up impact test data and also to real plant data. The results show better performance comparing to the conventional Hertz schemes.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.725-726
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• 2008

This paper deals with characteristic analysis of Linear Switched Reluctance Motor (LSRM) according to switching condition. When approved current in each phase by decided position, we made sure current and voltage according to turn-on, turn-off. In dynamic simulation of LSRM, through an experiment, we decided turn-on position of inductance profile. Also, we presented dynamic characteristic analysis model which is consisted at motor and sensor signal part, etc., and substitute circuit constant that get using magnetic equivalent circuit method, we confirmed current and voltage waveform.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.544-544
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• 2000

From ancient times. the diagnosis method of the oriental medicine has been Performed by curing diseases by means of rectifying and adjusting the unbalance in the Physiological function of the five viscera and the six bowels of a human body. Diseases have been diagnosed by the condition of blood circulation that cycles a human body through blood vessels by dint of the vitality of the heart, Based on such a systematic pulse diagnosis method, the article presents parameters that will be beneficial to clinical application on the basis of its analysis of the filtering for eliminating noises from pulse signals inputted from sensor group the digital hardware dealing with signals necessary for recognition algorithm. and the structure of diagnosis algorithm and components of pulse waveform.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1656-1658
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• 1998

This paper deals with a measurement system of a distance between lightning strokes and observatory station and spectrum analysis of electric fields radiated from lightning discharges. The distance measurement system, which consists of a loop type magnetic field sensor, a microphone and one chip microprocessor, is connected to a personal computer through RS232 port to acquire and process the data. This system is to use a difference of propagation velocity between an electromagnetic wave and a sonic wave produced by lightning discharge. Also, an electric field waveform and a frequency spectrum were investigated by an electric field measurement system with a hemisphere antenna and a spectrum analyzer with a biconical antenna and a log-periodic antenna, respectively. The results would be used as a basic reference to protect the power systems and electric circuits from lightning overvoltages.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.9
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• pp.396-402
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• 1986

Although the structure of the brushless DC motor is similar to the one of the permanent magnet synchronous motor, its operating characteristics are the same as those of the permanent magnet DC motor. This is the reason that the commutators and brushes in the permanent magnet DC motor can be replaced by the power semiconductor devices and rotor position sensors for the brushless DC motor. In this paper, a current control method is presented to make a sinusoidal current waveform for constant torque generation and the operating characteristics of the brushless DC motor using the resolver as the rotor position sensor is also presented and experimented.

• Journal of IKEEE
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• v.21 no.3
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• pp.256-259
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• 2017

SENT (single edge nibble transmission) is a serial communication protocol between automotive sensors and ECU (electronic control unit). SENT exploits digital waveform, so it has a simple and cheap architecture without transceiver circuits. Usually it is exploited as an embedded communication interface in the sensors. In this paper, a SENT interface was designed in Verilog HDL, fully complying with SAE J2716. It was implemented in FPGA, and verified on a test board. When it was synthesized, the gate count is about 2,500 gates in 0.18um technology.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3227-3229
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• 1999

수신된 초음파 파형이 표준 파형과 정합되는 시간을 수신 시점으로 사용함으로써 정확한 거리측정을 가능하게 하는 초음파 센서 거리계의 성능 개선을 제안하였다. 근거리 측정용으로 많이 사용되는 초음파센서는 다른 거리측정 시스템에 비해 하드웨어 구현이 용이하고 가격이 저렴한 장점이 있으나 센서 수신부측 Limit 회로의 threshold level의 선택 문제에 따른 거리 측정의 오차와 소음에 의한 거리 측정 오차가 매우 큰 문제가 되고 있다. 본 논문에서는 수신된 초음파 파형에 표준 파형을 정합하여 최대의 정합값을 가지는 시점을 수신 시간으로 간주하여, 소음환경비서도 거리 측정이 가능한 파형 정합 방법을 제한하였다. 본 논문의 실험을 통하여, 잡음이 심한 소음환경에서도 제안한 파형 정합 방법이 Threshold 방법 보다 초음파센서 거리 측정 성능이 개선됨을 확인할 수 있었다.