• Journal of Mechanical Science and Technology
• /
• 제19권10호
• /
• pp.1919-1931
• /
• 2005

Human joint motion can be kinematically described in three planes, typically the frontal, sagittal, and transverse, and related to experimentally measured data. The selection of reference systems is a prerequisite for accurate kinematic analysis and resulting development of the equations of motion. Moreover, the development of analysis techniques for the minimization of errors, due to skin movement or body deformation, during experiments involving human locomotion is a critically important step, without which accurate results in this type of experiment are an impossibility. The traditional kinematic analysis method is the Angular-based method (ABM), which utilizes the Euler angle or the Bryant angle. However, this analysis method tends to increase cumulative errors due to skin movement. Therefore, the objective of this study was to propose a new kinematic analysis method, Position-based method (PBM), which directly applies position displacement data to represent locomotion. The PBM presented here was designed to minimize cumulative errors via considerations of angle changes and translational motion between markers occurring due to skin movements. In order to verify the efficacy and accuracy of the developed PBM, the mean value of joint dislocation at the knee during one gait cycle and the pattern of three dimensional translation motion of the tibiofemoral joint at the knee, in both flexion and extension, were accessed via ABM and via new method, PBM, with a Local Reference system (LRS) and Segmental Reference system (SRS), and then the data were compared between the two techniques. Our results indicate that the proposed PBM resulted in improved accuracy in terms of motion analysis, as compared to ABM, with the LRS and SRS.

• International Journal of Contents
• /
• 제16권3호
• /
• pp.1-17
• /
• 2020

Human motion recognition is essential for user-centric services such as surveillance-based security, elderly condition monitoring, exercise tracking, daily calories expend analysis, etc. It is typically based on the movement data analysis such as the acceleration and angular velocity of a target user. The existing motion recognition studies are only intended to measure the basic information (e.g., user's stride, number of steps, speed) or to recognize single motion (e.g., sitting, running, walking). Thus, a new mechanism is required to identify the transition of single motions for assessing a user's consecutive motion more accurately as well as recognizing the user's body and surrounding situations arising from the motion. Thus, in this paper, we collect the human movement data through Android smartphones in real time for five targeting single motions and propose a mechanism to recognize a consecutive motion including transitions among various motions and an occurred situation, with the state transition model to check if a vulnerable (life-threatening) condition, especially for the elderly, has occurred or not. Through implementation and experiments, we demonstrate that the proposed mechanism recognizes a consecutive motion and a user's situation accurately and quickly. As a result of the recognition experiment about mix sequence likened to daily motion, the proposed adoptive weighting method showed 4% (Holding time=15 sec), 88% (30 sec), 6.5% (60 sec) improvements compared to static method.

• 대한물리치료과학회지
• /
• 제2권1호
• /
• pp.383-392
• /
• 1995

The purpose of this investigation was to determine the intratester reliability of measurements obtained with 3 Dimensional Motion Analysis System(3DMAS) by tester on normal subject. Twenty subjects between the ages of 9 and 29(x=22) were evaluated with 3DMAS using a test-retest reliability procedure after a familiarization session. Computerized 3DMAS was done with 4 50 - Hz CCD cameras connected to the ELITE system(B. T. S., Italy) and kinetic data were collected from the AMTI force platform(AMTI., U. S. A). Data were analyzed by the Eliclinic software to obtain gait parameters, joint angles and joint internal moment and power. Test-retest revealed intraclass correlation coefficients from .80 to .99. A series of paired t-tests revealed no significant differences between test and retest values. Finally, it was concluded that tester with 3DMAS could obtain reliable measurements with 3DMAS for determining kinetic, kinematic and gait parameters in normal subjects.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.679-684
• /
• 1993

This article presents an approach to estimate the general 3D motion of a polyhedral object using multiple, sensory data some of which may not provide sufficient information for the estimation of object motion. Motion can be estimated continuously from each sensor through the analysis of the instantaneous state of an object. We have introduced a method based on Moore-Penrose pseudo-inverse theory to estimate the instantaneous state of an object. A linear feedback estimation algorithm is discussed to estimate the object 3D motion. Then, the motion estimated from each sensor is fused to provide more accurate and reliable information about the motion of an unknown object. The techniques of multisensor data fusion can be categorized into three methods: averaging, decision, and guiding. We present a fusion algorithm which combines averaging and decision.

• Journal of the Korean Data and Information Science Society
• /
• 제22권3호
• /
• pp.549-553
• /
• 2011

In this paper, we deal with the problem of deciding the length of data for estimating the parameters in geometric Brownian motion. As an approach to this problem, we consider the change point test and introduce simple test statistic based on the cumulative sum of squares test (cusum test). A real data analysis is performed for illustration.

• 한국멀티미디어학회논문지
• /
• 제10권6호
• /
• pp.716-725
• /
• 2007

In this paper we describe a motion tracking algorithm for 3D human animation using stereo vision system. This allows us to extract the motion data of the end effectors of human body by following the movement through segmentation process in HIS or RGB color model, and then blob analysis is used to detect robust shape. When two hands or two foots are crossed at any position and become disjointed, an adaptive algorithm is presented to recognize whether it is left or right one. And the real motion is the 3-D coordinate motion. A mono image data is a data of 2D coordinate. This data doesn't acquire distance from a camera. By stereo vision like human vision, we can acquire a data of 3D motion such as left, right motion from bottom and distance of objects from camera. This requests a depth value including x axis and y axis coordinate in mono image for transforming 3D coordinate. This depth value(z axis) is calculated by disparity of stereo vision by using only end-effectors of images. The position of the inner joints is calculated and 3D character can be visualized using inverse kinematics.

• 한국융합학회논문지
• /
• 제11권2호
• /
• pp.271-279
• /
• 2020

스쿼트와 런지운동은 다양한 프리웨이트운동 중 몸통과 하체강화를 위한 중요한 운동으로 운동자세에 대한 이론적 근거 및 운동기준 동작의 확립을 통해 안전하고 효과적인 운동이 이루어져야 한다. 따라서 옵티멀 운동동작을 통한 부상 예방과 오류 동작에 대한 과학적 대응방안을 마련하기 위해 운동모형의 개발이 필요한 현실이며 이러한 목적으로 오류동작에 따른 자세교정을 위해 다양한 보조기구를 활용하는 방법이 효과적이다. 본 논문에서는 프리웨이트운동의 동적분석을 위해 지면반발력에 대응한 로드셀을 이용한 4포인트 하중검출을 통해 동적동작에 기반한 운동모형 분석시스템을 개발하고자 한다. 프리웨이트운동의 모형개발을 위해 동적 움직임을 단순화하여 구분동작에 따른 운동 모델링을 확립하고 동적인 동작분석을 통해 오류동작을 분석하고 보정하기 위한 수치정량화 데이터를 확보하였고 이를 활용할 수 있는 분석방법에 대한 타당성을 검증하였다.

• 한국정밀공학회지
• /
• 제32권4호
• /
• pp.377-386
• /
• 2015

Joint force/torque estimation by inverse dynamics is a traditional tool in biomechanical studies. Conventionally for this, kinematic data of human body is obtained by motion capture cameras, of which the bulkiness and occlusion problem make it hard to capture a broad range of movement. As an alternative, inertial motion sensing using cheap and small inertial sensors has been studied recently. In this research, the performance of inertial motion sensing especially to calculate inverse dynamics is studied. Kinematic data from inertial motion sensors is used to calculate ground reaction force (GRF), which is compared to the force plate readings (ground truth) and additionally to the estimation result from optical method. The GRF estimation result showed high correlation and low normalized RMSE(R=0.93, normalized RMSE<0.02 of body weight), which performed even better than conventional optical method. This result guarantees enough accuracy of inertial motion sensing to be used in inverse dynamics analysis.

• 한국실내디자인학회논문집
• /
• 제13권3호
• /
• pp.187-196
• /
• 2004

The purpose of this study is to develope'a digital space design process using user's motion data' through a theoretical and experimental study. In the progress of developing a developing of design process, this study was concentrated on searching a digital method applying user's interactive reflections. As introducing a concept of space form being generated by user's experiences, we proposed'a digital design process using user's motion data'. In the experimental stage, user's motion data were extracted and transferred as digital information by user behavior analysis, optical motion capture system, immersive VR system, 3D softwares com computer programming. As the result of this study, another useful digital design process was embodied by building up a digital form-transforming method using 3D softwares providing internal algorithm. This study would be meaningful in terms of attempting a creative and interactive digital space design method, avoiding dehumanization of existing ones through the theoretical study and the experimental approach.

• 한국컴퓨터그래픽스학회논문지
• /
• 제15권4호
• /
• pp.31-40
• /
• 2009

오늘날 실제 사람의 움직임을 촬영하여 얻은 동작 데이터는 영화제작, 게임 개발, 재활의학, 스포츠 분석 등의 다양한 분야에서 활용되고 있다. 시간에 따라 변화하는 일련의 자세로 이루어진 동작 데이터는 그 내용을 신속하고 정확하게 파악하는 것이 쉽지 않다. 이는 특히 많은 양의 동작데이터를 관리하고 원하는 동작을 찾고자 할 때 장애가 되곤 한다. 널리 사용되는 한 가지 방법은 동영상을 재생하듯이 관찰 시점을 진전시키는 동시에 3차원 공간상의 시야를 조절하는 것이다. 하지만 이 방식은 시점과 시야의 두 요소를 함께 고려하면서 데이터의 길이에 비례하는 시간 동안 지속적인 상호작용을 수행하여야 하는 번거로움을 야기한다. 본 논문은 동작 데이터를 분석하여 일련의 효과적인 관찰 시점 및 시야를 자동으로 찾아내고, 이로부터 생성된 이미지 시퀀스를 만화책 레이아웃 형식으로 배치하는 새로운 시각화 방법을 제안한다. 사용자는 만화책을 읽는 것처럼 바르게 전체 흐름을 파악할 수 있고, 원하는 동작이 등장하는 부분을 쉽게 찾아낼 수 있다. 이동, 권투, 환경과의 상호작용 등 여러 종류의 동작 데이터를 만화책 형식으로 시각화한 결과를 보임으로써 제안된 방법의 유용성을 확인하였다.