• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.872-883
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• 2018

Objective To replace camera-based three-dimensional motion analyzers which are widely used to analyze body movements and gait but are also costly and require a large dedicated space, this study evaluates the validity and reliability of inertial measurement unit (IMU)-based systems by analyzing their spatio-temporal and kinematic measurement parameters. Methods The investigation was conducted in three separate hospitals with three healthy participants. IMUs were attached to the abdomen as well as the thigh, shank, and foot of both legs of each participant. Each participant then completed a 10-m gait course 10 times. During each gait cycle, the hips, knees, and ankle joints were observed from the sagittal, frontal, and transverse planes. The experiments were conducted with both a camera-based system and an IMU-based system. The measured gait analysis data were evaluated for validity and reliability using root mean square error (RMSE) and intraclass correlation coefficient (ICC) analyses. Results The differences between the RMSE values of the two systems determined through kinematic parameters ranged from a minimum of 1.83 to a maximum of 3.98 with a tolerance close to 1%. The results of this study also confirmed the reliability of the IMU-based system, and all of the variables showed a statistically high ICC. Conclusion These results confirmed that IMU-based systems can reliably replace camera-based systems for clinical body motion and gait analyses.

• 한국운동역학회지
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• 제23권2호
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• pp.91-97
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• 2013

The purpose of this study was to compare the effect of a new warm-up condition, overloaded arm weights (721 g each arm, [OA]), on the bat speed during warm-up and immediately after warm-up with traditional warm-up conditions such as no-extra mass warm-up (control condition, [CO]) and overloaded bat warm-up (885 g donut on a bat, [OB]) conditions. Twenty male subjects who had competitive baseball experience participated in this study. Electromagnetic motion capture system was used to capture body segment motions. Results indicated that the OB showed significantly slower bat speed than the CO and OA did during warm-up (p<.05) and the bat speeds of OA and OB were similar. There was no main effect of different types of warm-up condition on the bat speed at post-warm-up swings. However, the first trial immediately after the OA and OB showed significant slower than the later trials (p<.05). Conclusively, the overloaded arm weights and overloaded bat did not show statistical superiority than the standard warm-up conditions in the deck circle and recovery time more than 3 minutes after loaded warm-up is recommended.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.1-9
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• 2009

인형은 여러 가지 재료를 사용하여 사람의 모습을 축소하여 만든 모형으로써 인형극의 한 구성요소를 담당하며 지금까지 인간의 문화 활동의 일부분을 담당해왔다. 그러나 전문가들의 감소, 기술 전수의 어려움 등으로 인해 인형극의 수요와 공급 감소현상이 지속됨에 따라 인형극의 자동화를 목적으로 하는 Robotic Marionette에 대한 연구가 세계적으로 진행되고 있다. 즉, 실제 전통적 줄 인형을 제어하는 컨트롤러를 모터로 대체하기 위한 구조 설계와 줄 인형의 동작표현을 위한 효율적인 프로세스의 개발이 필요하다. 따라서 본 논문은 첫째, 모셥캡쳐와 3D 프로그램을 통해 나온 모션 데이터의 가공 및 생성방법과 둘째, 줄 인형의 동작표현에 효과적인 방안을 제시한다. 셋째, 3차원 모션 데이터를 활용, 시뮬레이션의 선행 방안을 제시함에 따라 실제 Robotic Marionette System을 구축할 때 발생하는 제작 오류와 비용을 최소화하는 방법을 제안하도록 한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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• pp.745-747
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• 2005

최근 가상현실을 이용한 응용에 대한 수요가 증가하고 있다. 특히, 모션캡쳐 시스템을 이용해서 가상현실 공간상의 인체 캐릭터를 동작시킬 수 있는 콘텐츠는 교육용, 오락용등으로 활용 범위가 많다고 할 수 있다. 본 논문은 그래픽 3D 사물 객체, 3D 인체 캐릭터, 소리로 가상현실 공간을 구축할 수 있고, 모션캡쳐 장비로부터 실시간 획득되는 모션데이터를 이용해서 3D 인체 캐릭터를 동작시킬 수 있는 시스템 (가상스튜디오 시스템이라 부름)을 제안한다. 참고로, 우리의 조사에 의하면, 본 시스템과 같은 연구켤과는 거의 발견할 수 없었다. 본 시스템을 가상현실을 이용한 성경콘텐츠 제작에 활용해 본 결과 만족할 만한 성과를 얻었다.

• 한국산업융합학회 논문집
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• 제20권1호
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• pp.19-26
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• 2017

In this paper, we describe the design and performance of UAV system toward compact and fully autonomous quadrotors, where they can complete logistics application, rescue work, inspection tour and remote sensing without external assistance systems like ground station computers, high-performance wireless communication devices or motion capture system. we propose high-speed hovering flyght height control method based on state feedback control with image information from active camera and multirate observer because we can get image of the information only every 30ms. Finally, we show the advantages of proposed method by simulations and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2664-2666
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• 2005

In this paper, we develop the on board type image processing system using the CMOS sensor and the RISC type main processor. The main processor transmits YUV 4:2:2 type raw data captured by a CMOS image sensor to another processor(such as motion controller, PC, etc) via serial communication (rs232, SPI, I2C, etc). The role of another processor is line and obstacle detecting in image data received from the image processing board developed in this paper.

• Coupled systems mechanics
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• 제7권2호
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• pp.111-139
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• 2018

A successful methodology for modelling controlled destruction and progressive collapse of 2D reinforced concrete frames is presented in this paper. The strategy is subdivided into several aspects including the failure mechanism creation, and dynamic motion in failure represented with multibody system (MBS) simulation that are used to jointly capture controlled demolition. First phase employs linear elasto-plastic analysis with isotropic hardening along with softening plastic hinge concept to investigate the complete failure of structure, leading to creation of final failure mechanism that behaves like MBS. Second phase deals with simulation and control of the progressive collapse of the structure up to total demolition, using the nonlinear dynamic analysis, with conserving/decaying energy scheme which is performed on MBS. The contact between structure and ground is also considered in simulation of collapse process. The efficiency of the proposed methodology is proved with several numerical examples including six story reinforced concrete frame structures.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.470-476
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• 2016

This paper proposes a practical algorithm for the reduction of measurement errors due to drift in a micro-electromechanical system (MEMS) gyros that are used for a mobile robot. Any drift in a MEMS gyro will cause an unbounded growth of errors in the estimation of heading, which makes it nearly useless in applications that require high accuracy over a long operating time. In proposed method, maneuvers of a cleaning robot are observed through encoders' measurement process and a decision to correct bias drift will be made if necessary. The method used in this paper is called the "heading estimation filter". To evaluate the accuracy of the proposed method, a comparison was made between the estimation of the heading of the cleaning robot and one from a motion capture system.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.111-118
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• 1999

Recently computer can make cyberspace to walk through by an interactive virtual reality technique. An a avatar in cyberspace can bring us a virtual face-to-face communication environment. In this paper, an avatar is realized which has a real face in cyberspace and a multiuser communication system is constructed by voice transmitted through network. Voice from microphone is transmitted and analyzed, then mouth shape and facial expression of avatar are synchronously estimated and synthesized on real time. And also an entertainment application of a real-time voice driven synthetic face is introduced and this is an example of interactive movie. Finally, face motion capture system using physics based face model is introduced.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.178-186
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• 2021

The wave power extraction by multiple Wave Energy Converters (WECs) deployed in a Y-shaped Water Channel Resonator (WCR) has been investigated. A WCR consists of a long water channel, and a V-shaped wave guider installed at the entrance of a water channel. If the period of the incident waves coincides with the natural periods of the fluid in a WCR, resonance occurs, as a result, the internal fluid in a WCR is greatly amplified. To estimate the wave power by multiple WECs placed at the antinodal points in a WCR, the heave motion response, time-averaged power, and capture width ratio were calculated for several design parameters. Also, the systematic model tests were conducted in a 2D wave tank. The numerical results are in good agreement with the experimental data. It was verified that a WCR helps the WECs to produce electricity more effectively by amplifying the wave energy in a WCR.