• 한국전기전자재료학회논문지
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• 제24권1호
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• pp.81-88
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• 2011

A real time monitoring system from a PC has been developed which can be accessed through transmitted data, which incorporates an established low powered transport system equipped with a single chip combined with wireless sensor network technology from a three-axis acceleration sensor. In order to distinguish between static posture and dynamic posture, the extracted parameter from the rapidly transmitted data needs differentiation of movement and activity structures and status for an accurate measurement. When results interpret a static formation, statistics referring to each respective formation, known as the K-mean algorithm is utilized to carry out a determination of detailed positioning, and when results alter towards dynamic activity, fuzzy algorithm (fuzzy categorizer), which is the relationship between speed and ISVM, is used to categorize activity levels into 4 stages. Also, the ISVM is calculated with the instrumented acceleration speed on the running machine according to various speeds and its relationship with kinetic energy goes through correlation analysis. With the evaluation of the proposed system, the accuracy level stands at 100% at a static formation and also a 96.79% accuracy with kinetic energy and we can easily determine the energy consumption through the relationship between ISVM and kinetic energy.

• Journal of Positioning, Navigation, and Timing
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• 제11권2호
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• pp.119-126
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• 2022

This paper presents a method to reduce the vibration-induced noise effect of an inertial measurement device mounted on a self-driving vehicle. The inertial sensor used in the GNSS/INS integrated navigation system of a self-driving vehicle is fixed directly on the chassis of vehicle body so that its navigation output is affected by the vibration of the vehicle's engine, resulting in the degradation of the navigational performance. Therefore, these effects must be considered when mounting the inertial sensor. In order to solve this problem, this paper proposes to use an in-house manufactured vibration suppression device and analyzes its impact on reducing the vibration effect. Experimental test results in a static scenario show that the vibration-induced noise effect is more clearly observed in the lateral direction of the vehicle, but can be effectively suppressed by using the proposed vibration suppression device compared to the case without it. In addition, the dynamic positioning test scenario shows the position, speed, and posture errors are reduced to 74%, 67%, and 14% levels, respectively.

• 한국전문물리치료학회지
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• 제20권2호
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• pp.52-59
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• 2013

The purpose of this study was to determine the reliability and validity of the postural balance program which uses the movement accelerating field principles of posture balance training and evaluation equipment and smartphone movement accelerometer program (SMAP) in healthy young adults. A total of 34 people were appointed as the subject among the healthy young adults. By using Biodex stability system (BSS) and SMAP on the subject, the posture balance capability was evaluated. For the test-retest reliability, SMAP showed the intra-class correlation (ICC: .62~.91) and standard error measurement (SEM: .01~.08). BSS showed the moderate to high reliability of ICC (.88~.93) and SEM (.02~.20). In the reliability of inter-rater, ICC (.59~.73) as to SMAP, showed the reliability of moderate in eyes open stability all (EOSA), eyes open stability anterior posterior (EOSAP), eyes open stability medial lateral (EOSML) and eyes open dinamic all (EODA), eyes open danamic anterior posterior (EODAP), and eyes open danamic medial lateral (EODML). However, ICC showed reliability which was as low as .59 less than in other movements. In addition, BSS showed the reliability of high as ICC (.70~.75). It showed reliability which was as low as ICC (.59 less than) in other movements. In correlation to the balance by attitudes between SMAP and BSS, EOSML (r=.62), EODA (r=.75), EODML (r=.72), ECDAP (r=.64), and ECDML (r=.69) shown differ significantly (p<.05). However, the correlation noted in other movements did not differ significantly. Therefore, SMAP and BSS can be usefully used in the posture balance assessment of the static and dynamic condition with eyes opened and closed.

• Journal of Biosystems Engineering
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• 제36권3호
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• pp.223-230
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• 2011

Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised $0.05^{\circ}C$/min, $0.03^{\circ}C$/ min, and $0.08^{\circ}C$/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker's average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers' physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.

• 융합신호처리학회논문지
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• 제21권2호
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• pp.80-85
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• 2020

최근 학생 및 사무직 종사자에게서 근골격계 질환의 발병률이 증가하고 있으며, 바른 자세의 유지 및 교정 훈련의 필요성이 요구되고 있으나, 관련 연구는 부족한 현실이다. 기존 연구에서는 의자 방석부분에 멤브레인 센서 또는 압력센서를 배치하여 무게의 편중을 보거나, 사용자를 구속하는 센서를 부착하여 체위 변환을 측정하였다. 본 연구에서는 착용편의성을 고려한 체위 변환 감지 센서 디바이스를 개발하였으며, 측정한 각도를 분석앱을 통해 확인하였다. 앉은 자세에서 체위 변환을 측정하기 위하여 경추 및 척추에 IMU 센서로 구성된 센서 디바이스를 부착한다. 두 개의 센서에서 측정되는 체위의 변화값을 각도로 변환하였으며, 각도값은 실시간으로 분석앱을 통해 보여 진다. 본 연구에서는 체위 변화에 따른 실시간 변화값의 측정 가능성과, 착용편의성, 각도 측정의 경향성을 확인해 보았다. 향후 연구에서는 보다 정밀한 각도의 연산 및 동잡음의 보정을 위한 연구를 진행해야 한다.

• 패션비즈니스
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• 제26권5호
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• pp.91-104
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• 2022

In this study, a cycling smart wear for measuring cycling posture and motion was developed using a three-dimensional motion analysis camera and an IMU inertial sensor. Results were compared according to parts to derive the optimal smart device attachment location, enabling correct posture measurement and cycle motion analysis to design a pattern. Conclusions were as follows: 1) 'S-T8' > 'S-T10' > 'S-L4' was the most significant area for each lumbar spine using a 3D motion analysis system with representative posture change (90°, 60°, 30°) to derive incisions and size specifications; 2) the part with the smallest relative angle change among significant section reference points during pattern design was applied as a reference point for attaching a cycling smart device to secure detachable safety of the device. Optimal locations for attaching the cycling device were the "S-L4" hip bone (Sacrum) and lumbar spine No. 4 (Lumbar 4^th); 3) the most suitable sensor attachment location for monitoring knee induction-abduction was the anatomical location of the rectus femoris; 4) a cycling smart wear pattern was developed without incision in the part where the sensor and electrode passed. The wearing was confirmed with 3D CLO. This study aims to provide basic research on exercise analysis smart wear, to expand the smart cycling area that could only be realized with smart devices and smart watches attached to current cycles, and to provide an opportunity to commercialize it as cycling smart wear.

• 감성과학
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• 제8권1호
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• pp.29-36
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• 2005

본 연구에서는 관상동맥질환 환자들의 누운 자세가 자율신경계의 균형에 미치는 효과를 알아보고자 하였다. 관상동맥질환군 43명과 통제군 31명을 대상으로 세 가지 자세-똑바로 누운 자세(supine), 왼쪽으로 누운 자세(left), 오른쪽으로 누운 자세(right) -에서의 심박동변이도(HRV)를 측정하였다. HRV 변수들에 대한 분석 결과, 오른쪽으로 누운 자세에서 normalized high-frequency power가 가장 높았고, normalized low-frequency power는 가장 낮았다. 즉, 오른쪽으로 누운 자세에서 심장교감신경계의 활성도를 나타내는 HRV 변수들은 가장 낮은 반면에 심장부교감신경계의 활성도를 나타내는 HRV 변수들은 가장 높은 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.894-899
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• 2008

Measured sensor datum from a quadruped robotics is commonly used for recognizing physical environment information which controls the posture of robotics. We can advance the ambulation with this sensed information and need to synthesize various sensors for obtaining accurate data, but most of these sensors are expensive and require excessive load for the operation. Those defects can be serious problem when it comes to the prototype's practicality and mass production, and maintenance of the system. This paper suggests virtual sensor technology for avoiding previous defects and presents ways to apply a theory to a walking robotics through virtual sensor information which is trained with several kinds of actual sensor information from the prototype system; the general algorithm is initially based on the neural network theory of back propagation. In specific, we verified a possibility of replacing the virtual sensor with the actual one through a reaction force measurement experiment.

• 한국항해항만학회지
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• 제37권6호
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• pp.575-580
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• 2013

IMU(Inertial Measurement Unit)는 선박, 잠수함, 항공기 및 군용장비 응용분야에서 적용되어 자세 측정 영역에 주로 사용되고 있지만, 이런 IMU는 고가의 장비이기 때문에 특수 분야에서만 한정적으로 이용되어 왔다. 그러나 MEMS AHRS(MEMS : Micro Electro Mechanical System, AHRS : Attitude and Heading Reference System)의 현 기술 상황은 지능형 MEMS AHRS가 채택된 응용분야에서 가격이 높은 IMU를 대체 할 수 있는 수준에 이르고 있다. 본 논문에서는 자이로 센서, 가속도 센서, 지자기 센서를 사용한 AHRS를 이용하여 선박의 주요 운동 요소인 횡동요, 종동요, 선수동요 값을 측정할 수 있는 무선 선체 운동 측정 시스템을 개발하였다. 또한 AHRS 센서가 발생시키는 오차인 순간 가속도, 지자기의 영향 및 진동에 대응하기 위하여 칼만 필터링 기능이 탑재된 센서를 적용함으로서 최적의 성능을 실현하고자 하였다. 본 연구에서 구현한 AHRS 센서를 이용한 무선 선체 운동 측정 시스템을 이용하여 실선 실험을 실행하였으며, 선박의 제한적인 설치 상황에서도 편리하게 적용할 수 있을 것으로 보여진다. 향후 이 시스템이 선박에서 INS(Integrated Navigation System) 및 VDR(Voyage Data Recorder)과 같은 선박 장비와 호환되어 활용될 경우 항해 안전과 해양사고 분석에 유용하게 사용될 수 있을 것으로 판단된다.

• 대한임베디드공학회논문지
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• 제9권5호
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• pp.299-305
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• 2014

In this paper, a simple version of the hybrid navigation system using Kalman filter is proposed. The implemented hybrid navigation system is composed of a GPS to measure the position and the velocity, and a IMU(inertial measurement unit) to measure the acceleration and the posture of a mobile robot. A discrete Kalman filter is applied to provide the position of the robot by fusing both of the sensor data. When GPS signal is available, the navigation system estimates the position of the robot from the Kalman filter using position and velocity from GPS, and acceleration from IMU. During the interval until next GPS signal arrives, the system calculates the position of the robot using acceleration from IMU and velocity obtained at the previous step. Performance of the navigation system is verified by comparing the real path and the estimated path of the mobile robot. From experiments, we conclude that the navigation system is acceptable for the mobile robot.