• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.59-60
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• 2012

A large-scale construction project relies much on the efficiency of construction equipment. Therefore, efficient and accurate measurement on the productivity of construction equipment is one of important task in the construction industry. Based on the motivation, this paper proposes a 11-axis composite sensor for an automatic measurement of construction equipment. A 11-axis composite sensor is composed of a gyroscope, geomagnetic and accelerometer sensor for the purpose of real-time motion captures of construction equipment. It is expected that the proposed system can save considerable time, effort and cost of measuring a efficiency of construction equipment.

• Journal of Integrative Natural Science
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• v.17 no.3
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• pp.113-122
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• 2024

Advancements in sensor technology, particularly Inertial Measurement Units (IMU), are crucial in modern pose estimation. IMUs typically consist of accelerometers and gyroscopes (6-axis), with some models including magnetometers (9-axis). This study investigates the impact of sensor frequency on pose estimation accuracy using data from a 256Hz IMU sensor. The data sets analyzed include "spiralStairs," "stairsAndCorridor," and "straightLine," with frequencies varied to 128Hz, 64Hz, and 32Hz, and conditions categorized as stationary or dynamic. The results indicate that sensitivity remains high at lower frequencies under stationary conditions but declines in dynamic conditions. Performance comparison, based on Root Mean Square Error (RMSE) values, showed that lower frequencies lead to increased RMSE, thus diminishing model accuracy. Additionally, the Extended Kalman Filter (EKF) was tested as an alternative to Madgwick's algorithm but faced challenges due to insufficient sensor noise data.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.125-130
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• 2011

This paper shows a method to design complementary filter using least square. The complementary filter is one of useful filters estimating angle. The basic concept of this filter is to enhance advantages of each sensor that angle detecting using a gyroscope has good accuracy at a high frequency and an accelerometer at a low frequency. When designing complementary filter, the most commonly used method is using cut-off frequency. However, it may be not easy to obtain a cut-off frequency. This paper presents a systematic method to determine the coefficients of the complementary filter using well-known linear least squares minimizing error between estimating angle and true angle.

• Journal of Mechanical Science and Technology
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• v.16 no.4
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• pp.485-491
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• 2002

The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region (dead band) by the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference and an angular increment is not detected. This problem can be overcome by the mechanical dithering. The purpose of the mechanical dithering is to suppress the dead band, oscillate the monoblock about the rotation axis and add an external rotation rate. This paper presents the theoretical considerations of the mechanical performances of dither on the basis of the loading condition and angular characteristics due to the piezoelement deformation and the validity of theoretical equations are compared through FEM (Finite Element Method) simulations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.930-937
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• 1994

Straodown intertial navigation system(SDINS) is a navigational instrument necessary to guide and control a free vehicle. Dynamically Tuned Gyroscope(DTG) which is widely applied to SDINS convers a wide dynamic range and is simple and small. In study, the analysis of mechanical parts or sensor parts and research of balancing is performed for manufacturing a DTG. In error analysis the criterion considered during designing and manufacturing is established by quantitatively anayzing the effect of DTG performance by tolerance. And the theory of dynamic balancing is derived and unbalance is reduced through experiment. And the stiffness of flexure is verified by tuning experiment.

• International Journal of Control, Automation, and Systems
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• v.4 no.5
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• pp.615-623
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• 2006

The gyroscope free strap-down INS is composed only of accelerometers. Any gyroscope free INS navigation error is deeply affected by the accuracy of the sensor bias, scale factor, orientation and location error. However these parameters can be found by calibration. There is an important research issue about a multi-position calibration method in this paper. It provides a novel method to find the error parameters for the six-accelerometer INS. A superior simulation is shown that the multi-position calibration can find the specifications of a six-accelerometer INS in laboratory. From these parameters the six-accelerometer INS could apply in realistic navigation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.97-98
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• 2015

본 논문에서는 자이로스코프 센서를 장착한 헤드셋 모델을 소개한다. 이 헤드셋은 교육용으로 설계 되었으며 자이로스코프 센서로 사용자의 위치 및 상태에 따라 장애물에서 송출되는 소리가 다르게 들린다. 사용자의 키 정보를 입력하면 좌우 방향은 물론 상, 하를 인식하여 충돌 반경을 더 세부적으로 조절할 수 있다. 본 논문에서 제안하는 기술을 통하여, 후천적 시각장애인의 경우 '물리적 위험'이 적은 상태에서 지형 정보와 그에 따른 행동을 학습할 수 있을 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.345-348
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• 2009

본 연구에서는 실내에서의 위치추적을 위해 가속도 센서와 각속도 센서를 이용한 위치추적기법을 제안하였다. 기존의 실내 위치추적기법은 전파의 세기를 이용하여 위치추적을 수행하는 RSSI기법과 초음파를 이용한 방법이 제시되었다. 하지만 기존 실내위치추적 기법에서는 좌표 값을 알고 있는 고정된 노드를 필수적으로 사용해야하는 단점이 있다. 본 연구에서는 이러한 단점을 보완하기위하여 착용형 노드에 가속도센서와 각속도 센서를 부착하고 이동속도와 방향을 계측하여 실내에서의 위치추적을 수행하고자 하였다. 이를 위해 3축 가속도 센서와 2축의 각속도 센서를 사용하였으며, 센서로부터 출력되는 아날로그신호를 계측 및 무선전송하기 위하여 Zigbee기반의 무선 센서노드를 사용하였다. 무선센서노드로부터 측정된 가속도신호와 각속도 신호의 분석을 통해 실내위치추적 가능성을 평가하였으며, 평가 결과 가속도센서와 각속도 센서를 이용한 실내위치추적의 가능성을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.998-1013
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• 2013

Wireless wearable sensor networks have emerged as a promising technique for human motion tracking due to the flexibility and scalability. In such system several wireless sensor nodes being attached to human limb construct a wearable sensor network, where each sensor node including MEMS sensors (such as 3-axis accelerometer, 3-axis magnetometer and 3-axis gyroscope) monitors the limb orientation and transmits these information to the base station for reconstruction via low-power wireless communication technique. Due to the energy constraint, the high fidelity requirement for real time rendering of human motion and tiny operating system embedded in each sensor node adds more challenges for the system implementation. In this paper, we discuss such challenges and experiences in detail during the implementation of such system with wireless wearable sensor network which includes COTS wireless sensor nodes (Imote 2) and uses TinyOS 1.x in each sensor node. Since our system uses the COTS sensor nodes and popular tiny operating system, it might be helpful for further exploration in such field.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.7-14
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• 2017

A threshold-based fall recognition algorithm using a tri-axial accelerometer and a bi-axial gyroscope mounted on the skin above the upper sternum was proposed to recognize fall-like activities of daily living (ADL) events. The output signals from the tri-axial accelerometer and bi-axial gyroscope were obtained during eight falls and eleven ADL action sequences. The thresholds of signal vector magnitude (SVM_Acc), angular velocity (${\omega}_{res}$), and angular variation (${\theta}_{res}$) were calculated using MATLAB. When the measured values of SVM_Acc, ${\omega}_{res}$, and ${\theta}_{res}$ were compared to the threshold values (TH1, TH2, and TH3), fall-like ADL events could be distinguished from a fall. When SVM_Acc was larger than 2.5 g (TH1), ${\omega}_{res}$ was larger than 1.75 rad/s (TH2), and ${\theta}_{res}$ was larger than 0.385 rad (TH3), eight falls and eleven ADL action sequences were recognized as falls. When at least one of these three conditions was not satisfied, the action sequences were recognized as ADL. Fall-like ADL events such as jogging and jumping up (or down) have posed a problem in distinguishing ADL events from an actual fall. When the measured values of SVM_Acc, ${\omega}_{res}$, and ${\theta}_{res}$ were applied to the sequential processing algorithm proposed in this study, the sensitivity was determined to be 100% for the eight fall action sequences and the specificity was determined to be 100% for the eleven ADL action sequences.