• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.103-111
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• 2011

최근 만성질환을 예방하고 건강을 증진시킬 목적으로 신체활동에 대한 중요성이 인식되면서 신체활동 연구가 활발히 진행되고 있다. 본 연구에서는 3축 가속도 동작감지기 x, y, z축에 대한 $cm/s^2$의 가속도 합인 SVM(Signal Vector Magnitude)를 이용하여 신체활동 에너지 소비량 알고리즘을 구현하였다. 기존 실험을 통해 타당도가 입증된 COUNT 방식의 Freedson, Hendelman, Leenders, Yngve 알고리즘에 SVM 방식을 적용하여 구현 하였다. COUNT와 SVM 상관관계 분석을 위하여 총 10명의(성인 남성 5명, 여성 5명, 20 ~ 30 대) 피험자를 대상으로 실험을 진행하였다. 피험자는 트레드밀위에서 3단계 신체활동 (걷기: 3km/h, 빨리 걷기: 5km/h, 러닝: 8km/h)을 1주 간격으로 4주 간 반복 실험을 진행하였다. 실험결과 얻어진 COUNT와 SVM의 간의 상관관계를 분석하여 다양한 신체활동에 따른 맞춤형 에너지 측정 알고리즘을 구현하였다.

• 재활복지공학회논문지
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• 제5권1호
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• pp.27-33
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• 2011

3축 가속도 동작감지기를 이용하여 x, y, z축에 대한 가속도 합인 SVM(Signal Vector Magnitude)를 적용한 신체활동 에너지 소비량과 신체활동 강도 예측 알고리즘을 구현하였다. 신체 건강한 20~30대 성인 남성 5명, 여성 5명을 대상으로 골반 장골능에 엑티그라프(LLC, USA)와 피트미터(Fit.life. korea)를 착용하고 트레드밀위에서 3단계 신체활동(걷기: 3km/h, 빨리 걷기: 5km/h, 러닝: 8km/h)을 수행하였다. 각 신체활동 단계별로 7분간 신체활동을 수행하고 5분간 휴식을 통하여 각 신체활동 단계별로 안정화된 상태에서 실험하였다. 이러한 실험을 1주 간격으로 4주간 반복 실험을 진행하였다. 실험결과 얻어진 엑티그라프와 피트미터의 600여개 데이터 상관관계를 분석하여 METs와 kcal 그리고 신체활동 강도를 구분하는 알고리즘을 구현하였다.

• 제어로봇시스템학회논문지
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• 제16권12호
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• pp.1167-1175
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• 2010

This paper presents the use of the inertial measurement unit information and the infrared sector information for getting the position of an object. Travel distance is usually calculated from the double integration of the accelerometer output with respect to time; however, the accumulated errors due to the drift are inevitable. The orientation change of the accelerometer also causes error because the gravity is added to the measured acceleration. Unless three axis orientations are completely identified, the accelerometer alone does not provide correct acceleration for estimating the travel distance. We propose a way of minimizing the error due to the change of the orientation. In order to reduce the accumulated error, the infrared sector information is fused with the inertial measurement unit information. Infrared sector information has highly deterministic characteristics, different from RFID. By putting several infrared emitters on the ceiling, the floor is divided into many different sectors and each sector is set to have a unique identification. Infrared light based sector information tells the sector the object is in, but the size of the uncertainty is too large if only the sector information is used. This paper presents an algorithm which combines both the inertial measurement unit information and the sector information so that the size of the uncertainty becomes smaller. It also introduces a framework which can be used with other types of the artificial landmarks. The characteristics of the developed infrared light based sector and the proposed algorithm are verified from the experiments.

• 대한의용생체공학회:의공학회지
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• 제40권1호
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• pp.32-37
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• 2019

In this study, we designed a blending algorithm for rate adaptive pacing for cardiac pacemaker. Generally, rate adaptive pacing (RAP) is applied to patients whose heart rate does not rise during exercise for chronotropic incompetence (CI) patient. It is very important to develop an algorithm for RAP that can be properly applied to CI patients. In order to design an RAP algorithm we used dual sensors. Firstly, we designed a bio-signal measurement system based on the dual sensors, which are accelerometer and respiratory system. Secondly, we conducted treadmill test for the simulation experiment while using 3-lead ECG as reference. Finally, we designed a blending algorithm based on activation state of the dual sensors. The proposed blending algorithm was subdivided into three sections based on the accelerometer signal, which are rapidly increased section (W1), hardly changed section (W2), and decreased section (W3). Each weight is set aside for each section. To evaluate this algorithm, ten healthy adult males were participated. The correlation and Root Mean Square Error between the proposed algorithm and the reference were compared, and shown to be r=0.88 and 2.82 bpm, respectively. These results show that the proposed blending algorithm of dual sensors enables proper tracking of the heart rate during exercise. Also, it shows the possibility that the proposed blending algorithm can be applied to improve quality of life of the chronotropic incompetence patient.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.69-74
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• 2011

In the curving detection method by using an accelerometer, the ride comfort in the first car is worse than one in the others due to spend the time to calculate the tilting command and drive the tilting mechanism after entering in the curve. In order to enhance the ride comfort in the first car, the preditive curve detection method which predicts the distance from a train to the starting point of curve by using the GPS, Tachometer, Ground balise and position DB for track. In this study, we predicted and evaluated the ride comfort for predictive curve detection method in transient curves according to the shape and dimension of transient curve and the various driving speed. Also, we predicted the improvement of the ride comfort for predictive curve detection method by comparing with the result of the ride comfort for predictive curve detection method and for curve detection method using an accelerometer in the short transient curve.

• 로봇학회논문지
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• 제5권1호
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• pp.32-40
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• 2010

This paper proposes the technique of estimating the pipe thickness using the measured group velocity. To measure the group velocity from the accelerometer data in the frequency domain, Wigner-Ville distribution is utilized, which interprets the waveform of the shock wave. Using this measured group velocity, this paper proposes the technique to estimate the thickness of pipes with the impact on the pipe. The group velocity is estimated by the modeling correlation between the group velocity and the thickness of the pipe based on the propagation velocities. The correlation model between thickness and group velocity has been proved through the real experiments. The measured group velocity in the frequency-domain is the maximum at the center frequency of the bending waves in the modeling of the group velocity. In addition to these, a smoothing technique for analyzing lamb wave Wigner-Ville distribution has been introduced to improve the reliability of the data acquisition.

• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.1039-1044
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• 2000

In this paper, the error caused by the measurement delay in INS/GPS integrated systems with Kalman filtering is defined and analyzed through the analytical method and the simulation. It is proved that the error of measurement delay causes not only the position error but also the estimate error of the x-axis accelerometer bias when a vehicle turns. And the estimation method of the delay time and the compensation method using an extrapolation method are presented. The performance of the compensation method is shown by the analytic method and the simulation.

• 한국생산제조학회지
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• 제20권6호
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• pp.799-804
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• 2011

CFRP(Carbon Fiber Reinforced Plastics) has been used many industries aerospace, automobile, medical device and building material industries, etc. Because it is lighter than other metals and has good properties, such as rigidity, strength and wear. CFRP may be cured integrity. However, it needs postprocessing similar to drilling or endmilling for shape cutting and combination of various material. In this paper, tool dynamometer and accelerometer used to signal analysis for machining properties under various cutting conditions and tool shape changes. In addition, microscope used to verify the machined CFRP surface. As the results, it was found that the cutting force and the vibration were decreased in the increasing of cutting edge (2-flute < 4-flute < composite tool), and the good machined surface can be obtained in this experiments.

• 비파괴검사학회지
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• 제14권4호
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• pp.219-227
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• 1995

아르곤 이온 레이저를 광원으로 시편을 주기적으로 가열하여 광음향신호를 발생시키고 가속도 센서로 측정하는 2차원 광음향 현미경을 제작하였다. 다양한 결함을 가진 알루미늄 시편을 검사하고 광음향현미경의 특성을 조사하였으며 변조주파수, 레이저광의 단면적 등 실험 조건에 대한 의존성을 조사하여 적절한 실험조건을 확립하였다.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2012년도 제45차 동계학술발표논문집 20권1호
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• pp.7-10
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• 2012

본 논문에서는 스마트폰을 이용하여 도로 주행 정보를 기록하고 운전자에게 패턴 별 주행정보를 제공하는 라이프로그(Lifelog) 형태의 서비스에 목적을 두고 있다. 운전자의 도로 주행 데이터를 데이터베이스화한 이 정보는 다양하게 이용될 수 있다. 주행 패턴 인식은 이벤트 구간 검출 과정을 통한 패턴 구간을 검출하고 가속도 센서와 방향 센서, 즉 멀티 센서 기반으로 주행패턴을 인식한다. 주행 패턴을 분석 후 시간 정보를 이용하여 촬영된 영상 데이터에서의 패턴 구간 영상을 같이 제공한다. 이렇게 패턴 구간의 센서 스트리밍 정보와 영상을 제공하면 운전자의 운전 성향 및 주행 기록을 분석하는데 이용될 수 있다. 따라서 주행패턴 인식 알고리즘을 프로토타입으로 제안한다.