• 한국운동역학회지
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• 제31권3호
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• pp.199-204
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• 2021

Objective: The purpose of this study was to present a new idea of methodology to evaluate Poomsae performance using inertial measurement unit (IMU) sensors in terms of signal processing techniques. Method: Ten collegian Taekwondo athletes, consisting of five Poomsae elite athletes (age: 21.4 ± 0.9 years, height: 168.4 ± 11.3 cm, weight: 65.0 ± 10.6 kg, experience: 12 ± 0.7 years) and five breaking demonstration athletes (age: 21.0 ± 0.0 years, height: 168.4 ± 4.7 cm, weight: 63.8 ± 8.2 kg, experience: 13.0 ± 2.1 years), voluntarily participated in this study. They performed three different black belt Poomsae such as Goryeo, Geumgang, and Taebaek Poomsae repeatedly twice. Repeated measured motion data on the wrist and ankle were calculated by the methods of cosine similarity and Euclidean distance. Results: The Poomsse athletes showed superior performance in terms of temporal consistency at Goryeo and Taebaek Poomsae, cosine similarity at Geumgang and Taebaek Poomsae, and Euclidian distance at Geumgang Poomsae. Conclusion: IMU sensor would be a useful tool for monitoring and evaluating within-subject temporal variability of Taekwondo Poomsae motions. As well it distinguished spatiotemporal characteristics among three different Poomsae.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.62-66
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• 2023

With the advancement in technology and rapid increase in the demand for microelectromechanical systems (MEMS) based inertial measurement units (IMUs), high-volume production and test system remain a major challenge for the MEMS industry. To compete with the challenging market of Industry 4.0, here we developed an automatic test system to evaluate the performance of the ovenized IMU sensors as well as analyze the data. The automatic test system was developed by interfacing a commercial MEMS IMU (BMI 088) using LabVIEW. The BMI 088 was tested experimentally for long-term bias stability, ON/OFF bias repeatability, and root mean square (rms) noise. Furthermore, the data was analyzed through the developed test system. The results show that the automatic test system has improved the test time and reduced human effort. The developed automatic test system is a significant approach to MEMS research and development (R&D) to increase and improve the mass production of IMUs.

• 한국항행학회논문지
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• 제26권5호
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• pp.365-372
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• 2022

관성 측정 센서는 사람 행동 인식 시스템에 주로 사용되는 센서들에 비해 크기가 작고 가벼우며 낮은 비용으로 시스템의 경량화를 달성할 수 있다. 따라서, 본 논문에서는 관성 측정 센서를 이용한 이진 신경망 기반 걸음걸이 패턴 분석 시스템을 제안하고, 연산 가속을 위한 FPGA 기반 가속기 설계 및 구현 결과를 제시한다. 관성 측정 센서를 통해 걸음걸이에 대한 6가지 신호를 측정하고, 단시간 푸리에 변환을 이용하여 스펙트로그램을 추출한다. 높은 정확도를 가지는 경량화 시스템을 갖추기 위해 걸음걸이 패턴 분류에 BNN (binarized neural network) 기반 구조를 사용하였고, 검증 결과 97.5%의 높은 정확도와 메모리 사용량이 합성곱 신경망에 비해 96.7% 감소한 것을 확인하였다. 이진 신경망의 연산 가속을 위해 FPGA를 이용한 하드웨어 가속기 구조로 설계하였다. 제안된 걸음걸이 패턴 분석 시스템은 24,158개의 logic, 14,669개의 register, 13.687 KB의 block memory를 사용하여 구현되어 62.35 MHz의 최대 동작 주파수에서 1.5ms 내에 연산이 완료되어 실시간 동작이 가능함을 확인하였다.

• 센서학회지
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• 제28권6호
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• pp.345-354
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• 2019

The 3D position of pedestrians is a physical quantity used in various fields, such as automotive navigation and augmented reality. An inertial navigation system (INS) based pedestrian dead reckoning (PDR), hereafter INS-PDR, estimates the relative position of pedestrians using an inertial measurement unit (IMU). Since an INS-PDR integrates the accelerometer signal twice, cumulative errors occur and cause a rapid increase in drifts. Various correction methods have been proposed to reduce drifts. For example, one of the most commonly applied correction method is the zero velocity update (ZUPT). This study investigated the characteristics of the existing INS-PDR methods based on shoe-mounted IMU and compared the estimation performances under various conditions. Four methods were chosen: (i) altitude correction (AC); (ii) step length correction (SLC); (iii) advanced heuristic drift elimination (AHDE); and (iv) magnetometer-based heading correction (MHC). Experimental results reveal that each of the correction methods shows condition-sensitive performance, that is, each method performs better under the test conditions for which the method was developed than it does under other conditions. Nevertheless, AC and AHDE performed better than the SLC and MHC overall. The AC and AHDE methods were complementary to each other, and a combination of the two methods yields better estimation performance.

• International Journal of Advanced Culture Technology
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• 제11권1호
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• pp.296-305
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• 2023

The purpose of this study is to measure and compare the balance of motion between the left and right using a wearable sensor during upper limb exercise using an exercise equipment. Eight participants were asked to perform upper limb exercise using exercise equipment, and exercise data were measured through IMU sensors attached to both wrists. As a result of the PCA test, Euler Yaw(Left: 0.65, Right: 0.75), Roll(Left: 0.72, Right: 0.58), and Gyro X(Left: 0.64, Right: 0.63) were identified as the main components in the Butterfly exercise, and Euler Pitch(Left: 0.70, Right 0.70) and Gyro Z(Left: 0.70, Right: 0.71) were identified as the main components in the Lat pull down exercise. As a result of the Paired-T test of the Euler value, Yaw's Peak to Peak at Butterfly exercise and Roll's Mean, Yaw's Mean and Period at Lat pull down exercise were smaller than the significance level of 0.05, proving meaningful difference was found. In the Symmetry Index and Symmetry Ratio analysis, 89% of the subjects showed a tendency of dominant limb maintaining relatively higher angular movement performance then non-dominant limb as the Butterfly exercise proceeds. 62.5% of the subjects showed the same tendency during the Lat pull down exercise. These experimental results indicate that meaningful difference at balance of motion was found according to an increase in number of exercise trials.

• 반도체디스플레이기술학회지
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• 제23권1호
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• pp.71-78
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• 2024

In indoor environments, since global positioning system (GPS) signals can be blocked by obstacles, such as building structure. the performance of GPS-based positioning methods can be degraded because of the loss of GPS signals. To solve this problem, various localization schemes using inertial measurement unit (IMU) sensors, such as gyroscope, accelerometer, and magnetometer, have been proposed to enhance the positioning accuracy in indoor environments. IMU-based positioning methods can estimate the location of the user by calculating the velocity and heading angle of the user without the help of GPS. However, low-cost MEMS IMUs may lead to drift error and large bias. In addition, positioning errors in IMU-based positioning approaches can be caused by the irrelevant motion of the pedestrian. In this study, we propose an enhanced indoor positioning method that provides more reliable localization results by using the camera, light detection and right (LiDAR), and ARKit framework on the iPhone. Through reliable positioning results and augmented reality (AR) experiences, our indoor positioning system can provide indoor space guidance services.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.141.5-141
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• 2001

An attitude GPS receiver with 3 antennas obtains 3-dimensional attitude using GPS carrier phase measurement INS obtains the 3 dimensional navigation solution for IMU consisting of accelerometers and gyro. Ground-alignment process for the low -cost INS cannot be performed well due to the large sensor noise. Using the standard GPS receiver, however, continuous in-flight alignment for the INS becomes possible, and consequently, the errors in IMU sensors and navigation solution can be compensated. Especially with attitude measurement from the attitude GPS receiver, the compensation of errors in gyroscope and attitude would be done respite of the vehicle´s dynamics and their error covariance would be reduced. This paper presents ...

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.27-43
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• 2005

An INS(Inertial Navigation System) is composed of a navigation computer and an IMU(Inertial Measurement Unit), and can be applied to estimate a vehicle's state. But the inertial sensors assembled in the IMU are too complicated and expensive to use for the general application purpose. In this study, a new concept of inertial sensor system using magnetic levitation is proposed. The proposed system is expected to replace one single-axis rate or position gyroscope, and one single-axis accelerometer concurrently with a relatively simple structure. A simulation of the proposed system is given to describe the capability of this new concept.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.167-172
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• 2004

모바일 매핑시스템은 차량에 GPS(Global Positioning System), IMU(Inertial Measurement Unit), CCD 카메라 등을 탑재하고 공간 및 속성 정보를 취득하는 효율적인 방법이다. 모바일 매핑시스템은 도로 시설물 관리, 지도 갱신 등 다양한 분야에 이용되고 있다. 국외에서 개발된 모바일 매핑 시스템을 업그레이드하거나 새로운 센서를 추가 하고자 할 때 기존 시스템의 센서 통합 및 동기화 방안을 알 수 없으므로 시스템의 개선 및 향상이 어렵다. 본 연구에서는 모바일 매핑시스템의 개선 및 센서추가를 위해서 모바일 매핑시스템에 기본적으로 필요한 GPS, IMU, 그리고 CCD 카메라 등의 효율적인 통합 및 동기화 구현 방안을 제시하고, 동기화에 필요한 각 센서의 요구사항을 파악한 후 동기화 장비를 설계 및 제작하였다. 또한, 향후 추가될 센서인 레이져, 오도미터(Odometer) 등을 센서가 추가될 경우를 고려하여 통합장비를 설계하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.859-861
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• 2003

In order to present a space in details, it is indispensable to acquire 3D shape and texture simultaneously from the same platform. 3D shape is acquired by Laser Scanner as point cloud data, and texture is acquired by CCD sensor. Positioning data is acquired by IMU (Inertial Measurement Unit). All the sensors and equipments are assembled on a hand-trolley. In this research, a method of integrating the 3D shape and texture for automated construction of Digital Surface Model is developed. This Digital Surface Model is applied for efficient feature extraction. More detailed extraction is possible , because 3D Digital Surface Model has both 3D shape and texture information.