• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.441-443
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• 2009

Piezo Film Sensor를 이용하여 팔뚝의 상완 동맥에서 맥박 측정을 위한 센서부 최적 구조에 관한 연구를 하였다. 탈부착이 쉬운 팔뚝형 밴드 형태에 Piezo Film Sensor를 삽입하여 생체 신호를 측정 하였다. 센서부의 최적 구조를 알기 위해서 센서패드 구조물의 형태에서 매질 및 두께를 변화시켜 가면서 생체 신호의 크기를 비교하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.25-31
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• 2013

The AVC System which has operated in Highways has two-piezo sensors. In this system the piezo sensors are installed on parally each other this configuration has a defect about diversion driving and sensor damage. In this reserch, 3-Sensor AVC algorithm has been proposed which is supported enhance accuracy of the vehicle classification rate compare with usual 2-Sensor systems. This algorithm is allowed to calculate wheel tread, wheel width. The third inclinded piezo sensor can detec twheel tread, wheel width using signal processing. 3-Sensor AVC has been installed in real highway and the outcome performance has been proof.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.3
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• pp.268-274
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• 2004

Patch type piezo-polymer sensors for smart structures were experimented to detect elastic wave. The pencil lead braking test was performed to analyze the characteristics of patch-type piezo-polymer sensors such as polyvinyliden fluoride (PVDF) and polyvinylidene fluoride trifluorethylene (P(VDF-TrFE)) for several test specimens with various elastic wave velocities and acoustical impedances. The characteristics of the patch-type piezo-polymer sensor were compared with the commercial PZT acoustic emission (AE) sensor. The vacuum grease and epoxy resin were used as a couplant for the acoustic impedance matching between the sensor and specimen. The peak amplitude of elastic wave increased as the diameter of piezo-film and acoustical impedance of the specimen increased. The frequency detection range of the piezo-film sensors decreased with increasing diameter of the piezo-film sensor. The P(VDF-TrFE) sensor was more sensitive than the PVDF sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.985-988
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• 2001

A piezo-buzzer being used for the purpose of generation of audible frequency, which is a electric-acoustic transducer utilizing the inverse piezoelectric effect. Also it can be used for a pressure sensor according to the piezoelectric effect. But the output of a piezo-buzzer is a differential signal. In this study, we've made a system that can measure a real pressure by integration of output signal. According to our results, it could be found a possibility of application for pressure sensor by measurement of output characteristics when a piezo-buzzer was pressurized and depressurized, and by measuring of an error by means of the drift current of OP-Amp, etc..

• Journal of Digital Convergence
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• v.12 no.11
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• pp.387-393
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• 2014

In this research, we aimed to investigate the most optimum pulse wave sensor to ear label of live stocks among pulse wave piezo film sensor, conductive textile sensor, photo sensor. As a result of this research with application to 10 cattle, 10 pigs objects with pulse wave piezo film sensor, conductive textile sensor, photo sensor, photo sensor shows less standard deviation to average value than piezo film sensor or conductive textile sensor which means it is the most stable for the cattle. With pigs, piezo film sensor, conductive textile sensor and photo sensor all show stable pulse rate. Thus, to take pulse rate of livestock with curved body and long and dense coat such as cow, photo sensor will be considered as the most efficient mean.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.14-21
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• 2010

For the ubiquitous healthcare environment, real-time measurement of biomedical signals and accuracy of the measured biomedical information are very important. In addition, it is important to develop a healthcare device with low power In this paper, the synchronized pulse in a heartbeat was detected from the radial artery using the piezo film sensor, in order to eliminate inconvenience to wear a pulse detection finger probe. We can get a best output after applying the adaptive noise canceller using two piezo film sensor signals, pulse signal having motion artifacts and motion artifacts reference signal. To detect heartbeat, we use maximum point detection method from pulse removed motion artifacts.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.215-225
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• 2001

Stress waves monitored on the surface of structures under various loading conditions can provide useful information on the structural health status. In this paper, stress waves are measured by several sensors when a steel beam is impacted by a ball drop. The sensors used include the piezo-electric film Sensor, the electrical strain gage, and the ultrasonic transducer, and special attention is given to the pieza film sensor. The wavelet transform is used for the time-frequency analysis of dispersive waves propagating in the beam. The velocities of the wave produced in the team due to the lateral impact is found to be frequency-dependent and identified as the flexural wave velocity based on the comparisons with the Timoshenko beam theory. A linear impact site identification method is developed using the flexural wave, and the impact sites of the beam can be accurately estimated by the piezo film sensors. It is found that the piezo film sensor is appropriate for sensing stress waves due to impact and for locating impact sites in the beam.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.72-77
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• 2007

A pressure sensor is a sensing device to perceive inputing pressure and convert pressure with an electric signal. Currently, a domestic pressure sensor mostly uses mechanical methods. So, it uses many parts and its cost is high. Therefore, It is necessary to improve the weak points of an existing pressure sensor and develop the accurate and reliable pressure sensor using piezo resistance strain gages.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.03a
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• pp.40-62
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• 1995

A micro positioning system using piezoelectric actuators have very wide application region such as ultra-precision machine tool optical device measurement system. In order to keep a high precision displacement resolution it to useful to take a position sensor and feedback of the error. From the practical point of view high-resolution displacement sensor systems are very expensive and it is difficult to make such a sensitive sensor work properly in a poor operational environment of industry. In this study a piezo-electric micro-depth control system which does not require position sensor but piezoelectric voltage feedback has been developed. It is driven by hysteresis-considering reference input voltage calculated in advance and actuator/sensor characteristics of piezoelectric materials. From the result of experiments a fast and stable response of micro-depth control system has been achieved and an efficient technique to control the piezoelectric actuator suggested.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.509-523
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• 2023

The high-level nuclear waste (HLW) repository is exposed to complex environmental conditions consisting of high temperature, high humidity, and radiation, resulting in structural deterioration. Therefore, structural health monitoring is essential, and piezo sensors are used to detect cracks and estimate strength. However, since the monitoring sensors installed in the disposal tunnel and disposal container cannot be replaced or removed, the quantitative life of the monitoring sensor and its suitability must be assessed. In this study, the life of a piezo sensor for monitoring was assessed using an accelerated life test (ALT). The failure mode and mechanism of the piezo sensor under high temperature conditions were determined, and temperature stress's influence on the piezo sensor's life was analyzed. ALT was conducted on temperature stress and the relationship between temperature stress and piezo sensor life was suggested. The life of the piezo sensor was assessed using the Weibull probability distribution and the Arrhenius acceleration model. The suggested relationship can be used in multiple stress ALT designs for more precise life assessment.