• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.94-95
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• 2017

지정된 경로에서 6축 센서의 가속도와 각속도를 이용하여 물체의 이동거리를 계산하는 경우 가속도 센서에서 나오는 데이터는 중력을 사용하여 값을 보내주는데, 평평한 상태에서는 중력가속도만 나오므로 영향이 없지만 물체가 움직이면서 기울어지거나 흔들리는 경우 중력가속도와 운동가속도가 더해지고 이에 따라 이동거리 계산에 오차가 발생한다. 이 논문에서는 가속도와 각속도만으로 보정이 힘들다고 판단하여 적외선 센서를 사용하여 이동거리를 산출하는 방법을 제안하고 시스템을 개발한다. 제안한 시스템은 지정된 경로를 따라 이동할 때 적외선 센서를 이용하여 궤도의 구분선을 인식하여 기존 6축 센서로 계산된 이동거리를 보정한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.237-238
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• 2022

본 논문에서는 안드로이드 플랫폼 기반의 스마트폰에 내장된 중력 센서와 GPS 센서, NFC 태그를 활용한 조난 방지 애플리케이션을 설계하고 구현한다. 중력 센서를 통해 사용자의 움직임을 감지하고 GPS 센서를 사용해 사용자의 위치 정보를 확인하여 필요에 따라 회원가입 시 등록한 보호자에게 문자 메시지를 전송하거나 신고할 수 있도록 구현한다. 또한 등산 중 길을 잃었을 경우, NFC 태그를 통해 등산로의 정보를 이미지로 확인할 수 있도록 구현한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.1
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• pp.63-73
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• 2014

Recently, researches on DBRN(DataBase Referenced Navigation) system are being carried out to replace GNSS(Global Navigation Satellite System), as weaknesses of GNSS were found that are caused by the intentional interference and the jamming of the satellite signal. This paper describes the gravity gradient modeling and the construction of EKF(Extended Kalman Filter) based GGRN(Gravity Gradient Referenced Navigation). To analyze the performance of GGRN, fourteen flight trajectories were made for simulations over whole South Korea. During the simulations, we considered the errors in both DB(DataBase) and sensor as well as the flight altitudes. Accurate performances were found, when errors in the DB and the sensor are small and they located at lower altitude. For comparative evaluation, the traditional TRN(Terrain Referenced Navigation) was also developed and performances were analyzed relative to those from the GGRN. In fact, most of GGRN performed better in low altitude, but both of precise gravity gradient DB and gradiometer were required to obtain similar level of precisions at the high altitude. In the future, additional tests and evaluations on the GGRN need to be performed to investigate on more factors such as DB resolution, flight speed, and the update rate.

• ICROS
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• v.16 no.3
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• pp.40-45
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• 2010

물체의 운동을 측정하기 위하여 관성 센서(inertial sensor)에 대한 배경 지식이 없는 사용자가 가속도계(accelerometer)를 사용하고자 할 경우 센서의 이름이 주는 혼동에 의하여 물체의 운동 가속도(acceleration)를 쉽게 얻어낼 수 있으리라 기대하게 된다. 반면, 가속도계가 실제 측정하여 주는 값은 비력 가속도(acceleration due to specific force)에 해당되므로 적절한 처리를 부가하지 않으면 기대한 바와 같이 물체의 운동 가속도를 얻을 수 없다. 가속도계의 측정값으로부터 운동 가속도를 추출하기 위해서는 중력장 가속도 (gravitational acceleration), 중력 가속도 (acceleration due to gravity), 비력 가속도, 그리고 운동 가속도 사이의 관계를 명확하게 구분 이해할 필요가 있다. 본 고에서는 앞선 고들에서 다룬(막대) 벡터, 좌표값, 좌표계, 좌표변환행렬, 그리고 코리올리 효과 등의 개념을 확장하여 다양한 개념의 가속도들을 구분 설명하였다.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.181-190
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• 2009

This paper presents a multimodal emergency recognition system based on visual information, audio information and gravity sensor information. It consists of video processing module, audio processing module, gravity sensor processing module and multimodal integration module. The video processing module and gravity sensor processing module respectively detects actions such as moving, stopping and fainting and transfer them to the multimodal integration module. The multimodal integration module detects emergency by fusing the transferred information and verifies it by asking a question and recognizing the answer via audio channel. The experiment results show that the recognition rate of video processing module only is 91.5% and that of gravity sensor processing module only is 94%, but when both information are combined the recognition result becomes 100%.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.548-551
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• 2005

In this paper, three axial accelerometer was used to develop a small sensor module, which was attached to human body to calculate the acceleration in gravity direction by human motion, when it was positioned in any direction. To measure its wearer's walking or running motion using the sensor module, the acquired sensor data was pre-processed to enable its quantitative analysis. The acquired digital data was transformed to orthogonal coordinate value in three dimension and calculated to be single scalar acceleration data in gravity direction and normalized to be physical unit value.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.469-475
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• 2017

Workers in industrial fields are highly exposed to accidents or injuries caused by long working hours. An exoskeleton that is able to support the arm muscles of the worker and thereby reduce the probability of an accident and enhance working efficiency could be a solution to this problem. However, existing exoskeletons demand the use of high-priced sensors and motors, which makes them difficult to use in industrial fields. To solve this problem, we developed an arm assisting exoskeleton that consists only of mechanical components without any electronic sensors or motors. The exoskeleton follows the movement of the human arm by shoulder joint and ankle joint. In addition, counterbalance mechanisms are installed on the exoskeleton to support arm strength. The experimental validation of the exoskeleton was conducted using an EMG sensor, confirming the performance of the exoskeleton.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1185-1187
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• 2011

이 논문에서는 운전자의 운전 패턴을 분석하기 위한 멀티 센서 기반의 패턴 분석 알고리즘을 제안한다. 센서를 통해 얻어진 주행 데이터의 상관 관계를 비교, 분석하여 주행 패턴을 인식한다. 가속도 센서에 작용하는 중력값과 지자기 센서의 방향 데이터을 통해 각 운전 패턴을 인식하는 정확도를 높이는데 이용하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.254-259
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• 2013

A newly developed fall recognition algorithm using gravity weighted 3-axis accelerometer data as the input of HMM (Hidden Markov Model) is introduced. Five types of fall feature parameters including the sum vector magnitude(SVM) and a newly-defined gravity-weighted sum vector magnitude(GSVM) are applied to a HMM to evaluate the accuracy of fall recognition. A GSVM parameter shows the best accuracy of falls which is 100% of sensitivity and 97.96% of specificity, and comparing with SVM, the results archive more improved recognition rate, 5.2% of sensitivity and 4.5% of specificity. GSVM shows higher recognition rate than SVM due to expressing falls characteristics well, whereas SVM expresses the only momentum.

• Journal of the Korea Computer Graphics Society
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• v.19 no.4
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• pp.13-22
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• 2013

A motion capture system is widely used in movies, computer game, and computer animation industries because it allows for creating realistic human motions efficiently. The inertial motion capture system has several advantages over more popular vision-based systems in terms of the required space and cost. However, it suffers from low accuracy due to the relatively high noise levels of the inertial sensors. In particular, the accelerometer used for measuring gravity direction loses the accuracy when the sensor is moving with non-zero linear acceleration. In this paper, we propose a method to remove the linear acceleration component from the accelerometer data in order to improve the accuracy of measuring gravity direction. In addition, we develop a simple method to calibrate the joint axis of a link to which an inertial sensor belongs as well as the position of a sensor with respect to the link. The calibration enables attaching inertial sensors in an arbitrary position and orientation with respect to a link.