• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.591-598
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• 2016

For the mobile healthcare environment, it is important to measure the exact biomedical signals in real time, and another key point is to design mobile healthcare devices with low power consumption. In this paper, we propose a method in which the piezo film sensor(PFS), having a low power characteristic, is used to measure the pulse signal synchronized with the heart rate from the radial artery. The critical issue in the bio-signal processing is the existence of the motion artifacts. To dissolve this problem, we have applied the periodic moving average filter using the quasi-periodicity of the pulse signal in addition to the conventional method of the adaptive filtering using the reference signal. Results of simulation and experiments are presented to confirm that the quasi-periodicity of the PFS signal can be used to eliminate completely the motion artifacts which still appears after the adaptive filtering.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.15-19
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• 1984

본 연구는 piezo-electric transducer 등가회로의 모델링에 관한 연구로서 진동시에 발생하는 공진주파수와 harmonics까지 고려한 등가모델을 제시하였다. 실험결과 공진주파수만을 고려한 모델의 경우 harmonics를 제외한 부분에서 평균 6.5%의 오차가 발생하였으며 harmonics까지 고려한 모델에서는 평균오차가 5.3%로서 그 차이점을 줄일 수 있어 실제등가회로에 접근함을 알 수 있었다. 본 연구의 결과는 음향변환기의 전기적 특성을 파악함으로써 전기-음향 상사관계의 제반응용에 이용될 것이 기대된다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.05a
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• pp.95-99
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• 2000

본 연구는 전자라이터용 에폭시 정량공급장치의 개발에 관한 것으로써 기존의 수작업에 의한 생산을 자동화함으로 하여 품질의 균일화를 도모하고 또한 납기준수를 위한 생산성향상에 기반을 둔 개발로서 전자라이터의 핵심 부품이라고 할 수 있는 Piezo igniter 절연부에 에폭시를 정량으로 주입할 수 있게 함으로서 품질 및 생산목표를 달성하고 기업의 이윤을 극대화하는데 초점을 맞추었다.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.1
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• pp.30-35
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• 2009

In this paper, the type of inkjet heads and the control of head of inkjet printer are surveyed. The electronic parts of inkjet printer are composed of main- board and sub-board. The inkjet head is controlled by using these boards. The results from silver ink jetting experiment are given. The results show that the implemented inkjet system can give a satisfactory performance.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1065-1071
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• 2023

In this paper discuss with research developing an LSTM model for classifying the behavior of occupants within a residence. The multi-sensor consists of an IAQ (Indoor Air Quality) sensor that measures indoor air quality, a UWB radar that tracks occupancy detection and location, and a Piezo sensor to measure occupants' biometric information, and collects occupant behavior data such as going out, staying, cooking, cleaning, exercise, and sleep by constructed an experimental environment similar to the actual residential environment. After the data with removed outliers and missing, the LSTM model is used to calculate accuracy, sensitivity, specificity of the occupant behavior classification model, T1 score.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.301-306
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• 2022

With the recent widespread implementation of Internet of Things (IoT) technology driven by Industry 4.0, self-powered sensors for wearable and implantable systems are increasingly gaining attention. Piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), which convert biomechanical energy into electrical energy, can be considered as efficient self-powered sensor platforms. These are energy harvesters that are used as low-power energy sources. However, they can also be used as sensors when an output signal is used to sense any mechanical stimuli. For sensors, collecting high-quality data is important. However, the accuracy of sensing for practical applications is equally important. This paper provides a brief review of the performance advanced by the materials and structures of the latest PENG/TENG-based wearable sensors and intelligent applications applied using artificial intelligence (AI)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.22-25
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• 1995

In this paper, the physical characteristics of piezoelectric transducer which generates acoustic weve at microwave frequency were theoretically analized. We found that increasing electrode thickness is showed large distorthion on bandwidth. ZnO thin film were desposited by RF magnetron sputtering method. considering the sputtering parameters. Thickness of the desposited ZnO was 3.9 $\mu\textrm{m}$. In this experiment, we get that resistivity is 12.196${\times}$109 [cm$\Omega$], that resonance frequency is 827.47MHz Measuring insertion loss, we ascertained to possibility of transducer application for microwave frequency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1314-1319
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• 2004

The rosen types of piezo-transformers were prepared and electrical properties were investigated in order to establish the optimum parameters in the process of polarization for ferroelectric materials. Polarization was readily originated with increasing the external energy such as an applied voltage, time, and temperature so that the planar coupling factor and voltage gain were saturated under the conditions of over 14$0^{\circ}C$, applied voltage and time of 4 kV/mm and 3 minutes respectively. The empirical equation for domain rotation probability, which was in proportion to square of an applied voltage and temperature and square root of time, as functions of the above parameters was defined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.701-704
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• 2003

In this study, to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, PSN-PNN-PZT system ceramics were manufactured as a function of CuO addition. Its dielectric and piezoelectric characteristics were investigated. With increasing the amount of CuO addition, grain size was increased and density increased until 0.3wt% CuO. Taking into consideration electromechanical coupling factor(kp) of 0.53, mechanical quality factor(Qm) of 423 and ${\epsilon}r$ of 1759, it can be cincluded that the CuO 0.5wt% added composition sintered at $920^{\circ}C$ is suitable for piezoelectric transformer application if Qm is improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.697-700
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• 2003

This paper presents design and analysis of step-down piezoelectric transformer for application to AC-adapters. These transformers are consist of rectangular type and disk type multilayered piezoelectric ceramic plate. This piezoelectric transformer operated in third thickness resonance vibration mode. Finite element methode(FEM) was used for analysing transformer. Vibration mode and electric field of piezoelectric transformer were simulated at resonance frequency. As results, rectangular type transformer's output voltage was higher than the disk type. But disk type transformer's current was lagger than rectangular type. These results are assumed that disk type transformer's mixed vibration mode influence transformer's output characteristics. From these results, we expect that disk type piezoelectric transformer is more adoptable than rectangular plate type piezoelectric transformer for AC adapters.