• Journal of KSNVE
• /
• v.21 no.4
• /
• pp.25-29
• /
• 2011

자기변형(magnetostriction)에 관한 연재물 3번째로 이번 호부터는 본격적으로 자기변형 현상을 이용한 구동기(actuator)의 이론적인 모델링에 대해서 알아보기로 한다. 아직 필자의 이해의 수준이‘달인’의 경지에 이르지 않은 탓에 대부분의 내용은 기존의 논문의 내용을 요약 정리하거나 여러 논문들 간의 시각의 차이를 드러내는 방식으로 진행할 것임에 대하여 사전에 양해를 구한다. 또한 이 연재에서는 주로 구동기에 대한 내용을 언급하고 있으나 자기변형 물질 역시 피에조 물질과 마찬가지로 센서로 사용하는 것이 가능하기 때문에 이 연재에서 설명하는 내용은 센서를 설명할 때도 많은 경우 그대로 혹은 약간의 변형을 거쳐서 사용할 수 있음을 언급해둔다.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.951-952
• /
• 2011

발전소에 설치된 대용량 발전기는 고정자 권선을 지지하기 위해 축 방향으로 삽입된 슬롯 Wedge의 지지압력이 느슨해지면 절연파괴와 같은 각종 사고가 발생할 수 있다. 이를 예방하기 위해 주기적으로 Wedge 조임 상태를 점검하고 있으나 그동안 작업자의 손가락 감각으로 평가하던 방법을 가속도 진동 센서를 이용하여 주파수 스펙트럼을 분석함으로써 발전기 고정자 Wedge 조임 상태를 객관적으로 판정할 수 있도록 방법을 고안하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.692-693
• /
• 2004

We introduce a new velocity sensor, micro-flown sensor, which was developed by H-E de Bree. The sound absorption coefficients of a fiber material with the conventional pressure microphones and the micro-flown sensors were measured and compared. The experimental results show that both sensors could be well applied to measure the sound absorption coefficient but the pressure sensor was rather stable than micro-flown sensor

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.402-403
• /
• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.373.1-373
• /
• 2002

Impact is the most common type of dynamic loading conditions that give rise to impulsive forces and affects the vibrational characteristics of mechanical systems. Since the impact force and response are measured indirectly through the sensors, it is difficult to predict the impact force and acceleration. In this study, contact force model based on the Hertz law is proposed in order to predict the impact force correctly. (omitted)

• 한국방재학회:학술대회논문집
• /
• 2009.02b
• /
• pp.107.2-107.2
• /
• 2009

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.2
• /
• pp.99-109
• /
• 2018

The precision of the vibration-sensors, contact or non-contact types, is usually satisfactory for the practical measurement applications, but a sensor is confined to the measurement of a point or a direction. Although the precision and frequency span of the low-cost camera are inferior to these sensors, it has the merits in the cost and in the capability of simultaneous measurement of a large vibrating area. Furthermore, a camera can measure multi-degrees-of-freedom of a vibrating object simultaneously. In this study, the calibration method and the dynamic characteristics of the low-cost machine vision camera as a sensor are studied with a demonstrating example of the two-dimensional vibration of a cantilever beam. The planar image of the camera shot reveals two rectilinear and one rotational motion. The rectilinear vibration motion of a single point is first measured using a camera and the camera is experimentally calibrated by calculating error referencing the LDV (Laser Doppler Vibrometer) measurement. Then, by measuring the motion of multiple points at once, the rotational vibration motion and the whole vibration motion of the cantilever beam are measured. The whole vibration motion of the cantilever beam is analyzed both in time and frequency domain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.586-589
• /
• 2017

The vibration monitoring system using the sensor network is used in various fields. However, in case of the vibration of the existing products, the size of the monitoring system is increased due to the separation of the sensor data collection function and the communication function. In this paper, we design and implement a lightweight vibration monitoring system using the MQTT protocol, which is oneM2M device standard protocol for the Arduino and Ethernet modules, to monitor frequent earthquakes and vibrations in narrow places.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.394-399
• /
• 2012

In recent years, MEMS sensors show huge attraction in machine condition monitoring, which have advantages in power, size, cost, mobility and flexibility. They can integrate with smart sensors and MEMS sensors are batch product. So the prices are cheap. And the suitability of it for condition monitoring is researched by experimental study. This paper presents a comparative study and performance test of classification of MEMS sensors in target machine fault classification by 3 intelligent classifiers. We attempt to signal validation of MEMS sensor accuracy and reliability and performance comparisons of classifiers are conducted. MEMS accelerometer and MEMS current sensors are employed for experiment test. In addition, a simple feature extraction and cross validation methods were applied to make sure MEMS sensors availabilities. The result of application is good for using fault classification.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.11a
• /
• pp.79-83
• /
• 2000

해양에서의 기름유출이 가장 빈번하고 심각한 해양 오염이다. 이러한 오염의 초기 발견을 위한 센서로서 수정진동자의 표면에 활성탄을 도포한 센서의 측정감도와 안정성을 시험하고자 한다. 분말 활성탄과 페놀 수지를 센서의 표면에 도포하고 약1시간 가열하여 성형하였다. 물과 소금용액에 아세톤을 각각 소량 용해하여 유사 오염해수를 만들고 서로 다른 농도의 용액에서 공진주파수를 측정하여 아세톤 농도를 계산하였다. 실험결과를 고려할 때 센서의 제작이 적절하였고 아세톤 농도의 측정이 안정하며 충분히 예민하여 해수의 유기물 오염 측정에 사용할 수 있음을 알 수 있었다.