• ETRI Journal
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• 제35권2호
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• pp.356-359
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• 2013

We present a method for tracking and interaction based on hybrid sensing for virtual environments. The proposed method is applied to motion tracking of whole areas, including the user's occlusion space, for a high-precision interaction. For real-time motion tracking surrounding a user, we estimate each joint position in the human body using a combination of a depth sensor and a wand-type physical user interface, which is necessary to convert gyroscope and acceleration values into positional data. Additionally, we construct virtual contents and evaluate the validity of results related to hybrid sensing-based whole-body tracking of human motion methods used to compensate for the occluded areas.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.41-47
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• 2010

In this paper we suggest an improvement upon the previous method of estimating a body's attitude. This paper presents a method that overcomes the shortcomings of previous studies. Applying the method of separating the acceleration of gravity component from the accelerometer's output improves the performance of the attitude estimation and extends the scope. In order to apply the method of the attitude estimation in an actively moving body, a new acceleration value containing the acceleration of gravity is calculated. This paper also proposes the method which minimizes the estimation error in estimating the moving body's attitude which is changing rapidly. Finally, this paper suggests a method that detects the gyroscope's drift and compensates for this drift using accelerometer. Applying the method improves the performance of the attitude estimation.

• Journal of Information Processing Systems
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• 제20권2호
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• pp.159-172
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• 2024

The number of healthcare products available for pets has increased in recent times, which has prompted active research into wearable devices for pets. However, the data collected through such devices are limited by outliers and missing values owing to the anomalous and irregular characteristics of pets. Hence, we propose pet behavior recognition based on a hybrid one-dimensional convolutional neural network (CNN) and long short- term memory (LSTM) model using pet wearable devices. An Arduino-based pet wearable device was first fabricated to collect data for behavior recognition, where gyroscope and accelerometer values were collected using the device. Then, data augmentation was performed after replacing any missing values and outliers via preprocessing. At this time, the behaviors were classified into five types. To prevent bias from specific actions in the data augmentation, the number of datasets was compared and balanced, and CNN-LSTM-based deep learning was performed. The five subdivided behaviors and overall performance were then evaluated, and the overall accuracy of behavior recognition was found to be about 88.76%.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권8호
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• pp.459-466
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• 2000

In this paper, we propose an attitude controller for an unstructured object using CMG(Control Moment of Gyro) subsystem, which has a stabilizer function. The CMG subsystem consists of one motor for spinning the wheel and the other motor for turning the outer gimbal. While the wheel of CMG subsystem is spinning at high speed, applying force to the spin axis of the wheel leads the torque about the vertical axis. We utilize the torque to control the attitude of object in this study. For the stabilizer function, in additiion, holding the load at the current position, the power applied to the gimbal motor of CMG will be cut, which result in the braking force to stop the load by gyro effect. However, due to the gear reduction connected to outer gimbal, slow load motion cannot generate the braking force. Thus, in this study, we are willing to make a holding force by applying control power to the gimbal motor from the signal of piezoelectric gyroscopic sensor that detected the angular velocity of the load. These two features are demonstrated in experiment, carrying a beam with crane. As a result, load was started to rotate by controlling gimbal positiion and was stopped by turning off the gimbal power. Moreover, slow movement of the load was also rejected by additional control with gyroscopic sensor.

• 한국콘텐츠학회논문지
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• 제18권1호
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• pp.1-9
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• 2018

본 논문에서는 눈을 깜빡(eye-blink)일 때 발생하는 안전도(EOG, electro-oculogram) 신호를 이용하여 손을 사용하지 않는 가상현실 HMD(head mounted display)용 키보드 시스템을 제안하였다. 본 시스템은 디스플레이 소자, 자이로스코프센서, 중력센서, 뇌전도(EEG, electro-encephalogram) 센서 등으로 구성되며, 시스템의 제어 및 그래픽 처리 등을 위한 Unity3D 엔진으로 가상현실 HMD용 키보드 시스템을 구현하였다. 구현된 키보드의 방식은 한글의 경우 천지인 키보드 방식을 사용하였으며 영어, 숫자, 기호의 경우 $3{\times}4$ 방식을 사용하여 공간상의 문제를 해결하였다. 구현된 시스템을 통해 손을 사용하지 않고 목의 움직임과 안전도만으로 가상현실 HMD의 키보드 입력이 가능함을 확인하였다.

• 한국해양공학회지
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• 제31권2호
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• pp.164-169
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• 2017

Studies were performed on an ARS using SDINS's RLG and the geomatic sensor. To develop the ARS, experiments were performed to determine the characteristics of the RLG and geomatic sensor. Based on the results, to reduce the angular position errors of the RLG, which accumulate from the angular velocity data, an algorithm was studied that uses the Extended Kalman filter (EKF) to compensate the RLG data and geomatic sensor data. To verify the performance of the developed algorithm for reducing the cumulative angular errors, experiments that included the developed EKF were performed. Through these, it was shown that a drastic reduction in the angular errors of the RLG were achieved.

• 디지털산업정보학회논문지
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• 제18권4호
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• pp.47-54
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• 2022

In this paper, MEMS embedded system design implemented the sensor events via analyzing the characteristics that dynamically happened to an abnormal status in power IoT environments in order to guarantee a maintainable operation. We used three kinds of tools in this paper, at first Bluetooth Low Energy (BLE) technology which is a suitable protocol that provides a low data rate, low power consumption, and low-cost sensor applications. Secondly LSM6DSOX, a system-in-module containing a 3-axis digital accelerometer and gyroscope with low-power features for optimal motion. Thirdly BM1422AGMV Digital Magnetometer IC, a 3-axis magnetic sensor with an I2C interface and a magnetic measurable range of ±120 uT, which incorporates magneto-impedance elements to detect the magnetic field when the current flowed in the power devices. The proposed MEMS system was developed based on an nRF5340 System on Chip (SoC), previously compared to the standalone embedded system without bluetooth technology via mobile App. And also, MEMS embedded system with BLE 5.0 technology broadcasted the MEMS system status to Android mobile server. The experiment results enhanced the performance of MEMS system design by combination of sensors, BLE technology and mobile application.

• Advances in nano research
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• 제15권2호
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• pp.155-163
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• 2023

Exercise is beneficial to the body in some ways. It is vital for people who have heart problems to perform exercise according to their condition. This paper describes how an Android platform can provide early warnings of fatigue during wushu exercise using Photoplethysmography (PPG) signals. Using the data from a micro-electro-mechanical system (MEMS) gyroscope to detect heart rate, this study contributes an algorithm to determine a user's fatigue during wushu exercise. It sends vibration messages to the user's smartphone device when the heart rate exceeds the limit or is too fast during exercise. The heart rate monitoring system in the app records heart rate data in real-time while exercising. A simple pulse sensor and Android app can be used to monitor heart rate. This plug-in sensor measures heart rate based on photoplethysmography (PPG) signals during exercise. Pulse sensors can be easily inserted into the fingertip of the user. An embedded microcontroller detects the heart rate by connecting a pulse sensor transmitted via Bluetooth to the smartphone. In order to measure the impact of physical activity on heart rate, Wushu System tests are conducted using various factors, such as age, exercise speed, and duration. During testing, the Android app was found to detect heart rate with an accuracy of 95.3% and to warn the user when their heart rate rises to an abnormal level.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.567-568
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• 2018

최근 빈번히 발생하고 있는 지진, 건축물의 노후화에 따라 건축물 붕괴 및 기울어짐 사고 등이 자주 발생하고 있는 실정이다. 이런 건축물에 대한 재난을 방지하기 위하여 다양한 방법이 제시되고 있는 실정이다. 이에 본 논문에서는 IoT(Internet of Things)기반의 건축물 이상 유무를 실시간으로 모니터링 하여 건축물의 붕괴, 기울어짐 등에 대한 이상 징후현상을 사전에 제공하는 시스템을 제시한다. 다중첨단센서는 기울기 센서, 가속도 센서를 기반으로 센서별 검출된 데이터를 서버로 실시간 전송, 데이터를 축적하며, 설정된 임계치를 상위할 경우 대응할 수 있는 서비스를 제공 한다. 건축물의 붕괴, 기울어짐 등 현상에 대한 임계치 상위 이벤트 발생시 경고를 함으로, 건축물의 붕괴 및 기울어짐 현상에 대한 대피, 보수가 가능하여, 건축물에서 발생할 수 있는 재난에 대응할 수 있을 것이라고 사료된다.

• 한국항행학회논문지
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• 제21권1호
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• pp.126-131
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• 2017

본 논문은 오래된 옹벽과 같은 건축물이나 잠재적 위험을 내재한 건설 및 토목 구조물 등에 부착 가능한 블루투스 비콘 센서 노드를 활용하여 위험감지 및 대피/대처 서비스를 제공해줄 수 있는 스마트 안전 계측 시스템을 설계한다. 제안한 시스템은 블루투스 비콘을 활용하여 비콘이 설치된 지점의 가속도, 자이로, 지자계, 압력/고도, 온도/습도 등의 다양한 센서 데이터를 전송할 수 있으며 이러한 데이터를 활용하여 위험 감지, 예측, 경고 등의 다양한 서비스에 활용할 수 있다. 제안한 시스템의 실효성을 검증하기 위해 필드 테스트를 수행하였으며 옹벽의 변위값이 허용변위 38.5 mm 내에 존재한다는 것을 확인하였다.