• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.555-564
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• 2017

In this paper, a new technique for attitude and heading reference system (AHRS) using low-cost MEMS sensors of the gyroscope, accelerometer, and magnetometer is addressed particularly in vibration environments. The motion of MEMS sensors interact with the scale factor and cross-coupling errors to produce random errors by the harsh environment. A new adaptive attitude estimation algorithm based on the Kalman filter is developed to overcome these undesirable side effects by analyzing windowed measurement error covariance. The key idea is that performance degradation of accelerometers, for example, due to linear vibrations can be reduced by the proposed measurement error covariance analysis. The computed error covariance is utilized to the measurement covariance of Kalman filters adaptively. Finally, the proposed approach is verified by using numerical simulations and experiments in an acceleration phase and/or vibrating environments.

• Journal of Biomedical Engineering Research
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• v.35 no.5
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• pp.111-118
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• 2014

As assessment of quantitative energy expenditure for effective exercise is becoming more important, many researches about the monitoring system for exercise status or result have been actively carried out. In this case, however, bicycle riders feel restrained and uncomfortable because the riders should wear a belt-type electrocardiograph or a watch-type accelerometer or GPS system during the assessment of bicycle exercise. In this study, therefore, an electrocardiograph based on textile electrode was developed for measuring ECG and calculating heart rate from the bicycle rider without feeling restraint, and smartphone application was also developed for monitoring the heart rate.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1205-1208
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• 2014

본 논문은 항상 지니고 있는 스마트폰으로 노트북 사용자가 마우스를 휴대해야 하는 불편함을 해결하기 위해 이를 대체할 수 있는 안드로이드용 스마트폰 마우스 어플리케이션을 설계하였다. 우리는 기존의 다른 연구나 실제 이미 출시된 마우스 어플리케이션들과 달리, 블루투스를 이용하여 인터넷을 사용할 수 없는 상황에서도 작동하도록 하였으며 터치패드가 아닌 가속도 센서를 통해 실제 마우스처럼 동작을 인식하도록 하였다. 또한, 스마트폰 어플리케이션의 장점인 추가적인 기능을 쉽게 추가할 수 있다는 점을 살려서 진동 모드, 자동 연사, dpi 조절 기능 등을 포함한 게이머 마우스로 설계하였다. 정확한 마우스 포인터의 이동을 표현하기 위해 운동방정식으로 센서값을 속도로 바꿔서 이를 사용하였다. 그리고 센서 오차로 인한 오류 막기 위해 센서값을 필터링하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1908-1909
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• 2007

The design of an intelligent toothbrush, capable of monitoring brushing motion, orientation through the grip axis, during toothbrushing is described. Inappropriate Toothbrushing styles, even in adults, sometimes cause dental problems, cavities, gingivitis, etc. This smart system provides user to monitor his or her brushing pattern using accelerometer and magnetic sensors for evaluation of toothbrushing style. Directional information of toothbrush with respect to earth's magnetic field and activity data were measured by a miniaturized low-power micro- controller, MSP430 and transmitted to personal computer by 2.4GHz radio transmitter, nRF2401. A personal computer provides an on-line display of activity and orientation measurements during toothbrushing. The signal trace is then analyzed to extract clinically relevant measurement. This preliminary study showed that the proposed monitoring system was conceived to aid dental care personnel in patient education and instruction in oral hygiene regarding brushing style.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1089-1092
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• 2001

In order to measure the vibration of a ribbed clindrical shell, the principle of reciprocity has been implemented. An accelerometer was fixed at the position defined as the excitation point. An impact hammer was used to tap at the response array points (64 points) located along the circumference of the shell. The frequency response function was reciprocally measured at each point in turn. The response data was processed to obtain the frequency/wavenumber spectrum. From the spectrum the characteristics of wave propagation on the ribbed cylindrical shell have been observed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.883-886
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• 2005

This paper proposed a wireless measurement system (WMS) for an effective condition monitoring using wireless communication. WMS consists of two parts: transmitter(TM) acquired a dynamic signal from physical system using ICP type accelerometer sensor. An acquired signal modulated through the low/high pass filter and amplifier in DAQ board, which converted to digital signal. Embedded board(E-board) transferred digital signals to base station(BS) through the socket IEEE.802.11.b. BS is adopted IOCP server structure. Because it can acquired signal well during transferred digital signal. Signal processing used LabVIEW Library, BS(server) designed to realize multi-thread using visual C++.NET for 1 many meaning data processing

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.6
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• pp.483-500
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• 2007

Emerging sensor-based structural health monitoring (SHM) technology can play an important role in inspecting and securing the safety of aging civil infrastructure, a worldwide problem. However, implementation of SHM in civil infrastructure faces a significant challenge due to the lack of suitable sensors and reliable methods for interpreting sensor data. This paper reviews recent efforts and advances made in addressing this challenge, with example sensor hardware and software developed in the author's research center. It is proposed to integrate real-time continuous monitoring using on structure sensors for global structural integrity evaluation with targeted NDE inspection for local damage assessment.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.313-315
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• 2014

안드로이드는 스마트폰과 같은 휴대용 장치에 널리 사용되는 모바일 운영체제로서, 그를 기반으로 하는 다양한 안드로이드용 애플리케이션이 활발히 개발되고 있다. 본 논문에서는 안드로이드 폰을 PC 의 원격 입력 장치로 사용할 수 있도록 하는 애플리케이션을 개발한다. 본 논문에서 개발한 애플리케이션은 안드로이드 폰을 원격 마우스, 원격 키보드, 원격 터치패드로 사용할 수 있도록 해줌으로써, 다양한 상황에서 PC 에 대한 입력을 편하고 쉽게 할 수 있다. 본 논문의 애플리케이션은 PC 에 설치되어 구동되는 윈도우 애플리케이션과 안드로이드 폰에 설치되어 구동되는 안드로이드 애플리케이션으로 구성되며, 안드로이드 애플리케이션의 입력 요청을 소켓 통신을 통해 윈도우 애플리케이션에 전달한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.385-388
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• 2012

본 논문에서는 스마트 폰에 내장된 3축 가속도 센서를 이용해 제스처 훈련 및 테스터 데이터를 수집하고, DTW(Dynamic Time Warping) 알고리즘을 근간으로 하는 효과적인 제스처 인식 방법을 제안한다. 본 논문에서 제안하는 제스처 인식 방법의 성능을 분석하기 위해 안드로이드 스마트 폰에서 동작하는 제스처 인식 프로그램을 개발하였고, 이것을 이용해 수행한 성능실험 결과를 소개한다.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.87-91
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• 2019

In this paper, we have development of horizontal attitude monitoring system for agricultural robots. A two-axis gyro sensor and a two-axis accelerometer sensor are used to measure the horizontal attitude angle. The roll angle and pitch angle were measured through the fusion of the gyro sensor signal and the acceleration sensor signal for the horizontal attitude monitoring of the robot. This attitude monitoring system includes GPS and Bluetooth communication module for remote monitoring. The roll angle and pitch angle can be measured by the error of less than 1 degree and the linearity and the reproducibility of the output signal are excellent.