• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.872-875
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• 2004

In this paper, thermal response analysis of a temperature controlled three-axis accelerometer for high temperature environments with integrated micro-heaters and temperature sensors is investigated with finite element method (FEM) program, ANSYS and infrared thermal measurement systems. And availability to application fields from a viewpoint about short thermal response time is discussed. In this paper, the time of three-axis accelerometer for high temperatures becoming $300^{\circ}C$ by integrated micro-heaters and temperature sensors to reduce thermal drift characteristics was analyzed as a thermal response time of this device. The simulated thermal response time (time until SOI piezoresistors actually becomes $300^{\circ}C$) of three-axis accelerometer for high temperatures with ANSYS is about 0.6s, and measured result with infrared temperature measurement systems is about 0.64s. Experimental results using infrared thermal measurement systems agreed well with these theoretical results.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.506-513
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• 2014

In recent years, research on user's activity recognition using a smart phone has attracted a lot of attentions. A smart phone has various sensors, such as camera, GPS, accelerometer, audio, etc. In addition, smart phones are carried by many people throughout the day. Therefore, we can collect log data from smart phone sensors. The log data can be used to analyze user activities. This paper proposes an approach to inferring a user's physical activities based on the tri-axis accelerometer of smart phone. We propose recognition method for four activity which is physical activity; sitting, standing, walking, running. We have to convert accelerometer raw data so that we can extract features to categorize activities. This paper introduces a recognition method that is able to high detection accuracy for physical activity modes. Using the method, we developed an application system to recognize the user's physical activity mode in real-time. As a result, we obtained accuracy of over 80%.

• 한국항공우주학회지
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• 제36권7호
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• pp.674-679
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• 2008

본 논문에서는 안정된 진동을 얻기 위한 자동 이득 제어(AGC) 루프를 이용하여 자가 유지 특성을 갖는 공진형 가속도계를 설계하였다. 제안된 가속도계의 기본 원리는 가속도 입력시, 가변 진동의 진폭을 일정하게 유지시키는 방법을 이용한다. 시스템 모델링과 진동의 포락선을 고려한 루프 설계 및 변환를 통하여 다양한 가속도 입력 하에서 진동 신호의 진폭을 일정하게 유지하도록 제어기를 설계하였고, 시뮬레이션 결과를 통해 실현가능성을 확인하였다. 따라서 고안된 공진 가속도계는 산업과 민간 응용 분야에 있어서 제어용 등급의 관성 측정 시스템에 적용될 수 있을 것으로 기대한다.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.334-343
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• 2014

In this paper, we suggest a method to improve the fusion of an accelerometer and gyro sensor by using a Kalman filter to produce a more high-quality respiration signal to supplement the weakness of using a single accelerometer. To evaluate our proposed algorithm's performance, we developed a chest belt-type module. We performed experiments consisting of aerobic exercise and muscular exercises with 10 subjects. We compared the derived respiration signal from the accelerometer with that from our algorithm using the standard respiration signal from the piezoelectric sensor in the time and frequency domains during the aerobic and muscular exercises. We also analyzed the time delay to verify the synchronization between the output and standard signals. We confirmed that our algorithm improved the respiratory rate's detection accuracy by 4.6% and 9.54% for the treadmill and leg press, respectively, which are dynamic. We also confirmed a small time delay of about 0.638 s on average. We determined that real-time monitoring of the respiration signal is possible. In conclusion, our suggested algorithm can acquire a more high-quality respiration signal in a dynamic exercise environment away from a limited static environment to provide safer and more effective exercises and improve exercise sustainability.

• 한국소음진동공학회논문집
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• 제23권1호
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• pp.17-24
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• 2013

The process of producing high precision and light weight product is always exposed to impact load or shock. Because of this, isolator device is required. To measure the response of the isolator, accelerometer is practically used. However, the measured response of the accelerometer is different to the response of the isolator. To predict the response of the accelerometer and the isolator, 2-DOF damped system with an input shock is modeled using numerical analysis. 1-DOF damped system with a base excitation is also used to predict the response of the isolator. The mass ratio, damping ratio, and natural frequency ratio are then varied. The predicted responses from the two modeling approaches are compared and large errors are found.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.115-120
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• 2008

There are many typesof accelerometer sensor. There was mainly used high-g accelerometer to obtain data for vehicle in crash test. Accelerometer was mounted on test vehicle with mounting blocks. Test result can be influenced by condition of mounting i.e. bonding material and type of block. These influences can be evaluated to variation of sensitivity in calibration test. In this paper, Calibration test were carried out for 3 types of bonding material i.e. stud, beewax and double side tape. Other factor was taken into consideration by 3-types for mounting block. All test was conducted by sinusoidal signal vibrator up to 4500Hz. In order to investigate influence for sensitivity from different input voltage in the calibrator, the same test was repeated. Test results were compared with standard accelerometer data. Relative sensitivities and phases were showed small difference in sensitivity for bonding materials with one block, but significant one for another block and different input voltage below 1000Hz.

• 센서학회지
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• 제13권6호
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• pp.430-435
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• 2004

The resolution of the accelerometer, fabricated with MEMS technology is mainly affected by mechanical and electrical noise. To reduce mechanical noise, we have to increase mass of the structure part and quality factor related with the degree of vacuum packaging. On the other hand, to increase mass of the structure part, the thickness of the structure must be increased and ICP-RIE is used to fabricate the high aspect ratio structure. At this time, footing effect make the sensitivity of the accelerometer decreasing. This paper presents a hybrid SOG(Silicon On Glass) Process to fabricate a lateral silicon accelerometer with differential capacitance sensing scheme which has been designed and simulated. Using hybrid SOG Process, we could make it a real to increase the structural thickness and to prevent the footing effect by deposition of metal layer at the bottom of the structure. Moreover, we bonded glass wafer to structure wafer anodically, so we could realize the vacuum packaging at wafer level. Through this way, we could have an idea of controlling of quality factor.

• 한국구조물진단유지관리공학회 논문집
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• 제16권3호
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• pp.11-22
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• 2012

본 연구는 RTK-GPS (Real Time Kinematic-Global Positioning System) 측위법을 이용한 변위 계측 결과, 가속도계를 이용한 변위계측 결과, 그리고 LVDT(Linear variable differential transformer)의 변위계측 결과를 비교하여 RTK-GPS와 가속도계 센서를 구조물에 적용할 때의 문제점들을 파악하였다. 또한, 관측빈도와 측위 정확도를 향상시킨 RTK-GPS와 가속도계를 이용한 변위계측 결과를 통합 계산하여 절대변위인 LVDT와 비교를 통해 생성된 통합 변위의 정확도와 타당성을 확인하였다.

• 한국인터넷방송통신학회논문지
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• 제17권2호
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• pp.179-190
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• 2017

Hand Accelerometer는 인간신체 운동 패턴을 실시간으로 파악하는데 널리 사용되고 있다. 그러므로 행동 유형을 정확하게 파악하는 것은 아주 중요하다. 이 과정에서 각 행동유형의 형태를 미리 정확하게 파악하는 것이 중요하다. 인간의 신체 행동은 센서를 통해 수집된 시계열 데이터로 표현된다. 이 데이터는 비안정적, 비선형적 성격을 가지고 있다. 그래서 이런 성격의 데이터의 유형을 효율적으로 추출하는 방법을 찾는 것은 매우 중요하다. 힐버트-황 변환은 비안정적 비선형적 요소를 시계열데이터에서 효율적으로 추출하는 방법이다. 이 방법을 위의 시계열 데이터에 적용한 결과 핵심패턴이 성공적으로 추출되었다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.162-165
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• 2016

본 논문은 윗몸 일으키기를 측정하는 타이젠 웨어러블 디바이스용 웹 어플리케이션의 정확도 개선에 대한 연구를 수행한다. 본 연구에서 사용하는 어플리케이션은 디바이스의 Accelerometer 센서를 이용하여 사용자의 윗몸 일으키기 자세를 측정한다. 올바른 윗몸 일으키기 자세에 대한 Accelerometer 데이터를 분석한 후 이를 토대로 운동역학적 데이터를 이용한 알고리즘을 구현하여 어플리케이션을 제작하고, 이를 기존에 존재하는 윗몸 일으키기 측정 앱과 비교했을 때 9.25%의 정확도를 개선할 수 있다.