SB Charite III ® 인공 추간판이 설치된 기능 척추 단위의 하중 분포: 유한 요소 분석 연구

윤상훈,김현집 대한척추신경외과학회 2010 Neurospine Vol.7 No.4

Objective: To evaluate the effects of SB Charite III® artificial disc implantation on the biomechanics of functional spinal units. Methods: A nonlinear intact osteoligamentous three-dimensional finite element model of L4-L5 was developed using 1-mm CT scan data from a human volunteer, and the material properties of each element were determined. The model was validated using biomechanical data. A model that was implanted with SB Charite III® artificial discs via an anterior approach was also developed. The stresses and strains of the vertebral bodies and surrounding spinal ligaments were investigated. The implanted model was compared to the intact model in terms of range of motion, force on facet joints with flexion-exten- sion, lateral bending, and axial rotation under 400N preloading. Results: There were no significant differences between the findings of this finite element study and other reports in the literature. Our analytical method proved useful method for the biomechanical evaluation of the effects of artificial disc implan- tation. The implanted model revealed an increased range of motion in flexion-extension, lateral bending, and axial rotation compared to the intact model. The stresses on facets were greater in the implanted model than in the intact model. Conclusion: The model that was implanted with artificial discs showed increased segmental motion and stress on the facet joints compared to the intact model. We hypothesize that the removal of the anterior longitudinal ligament is the major cause of increased segmental motion and stress on the facet joints in the implanted model. The development of new artificial discs should focus on compensating for these unwanted results. Objective: To evaluate the effects of SB Charite III® artificial disc implantation on the biomechanics of functional spinal units. Methods: A nonlinear intact osteoligamentous three-dimensional finite element model of L4-L5 was developed using 1-mm CT scan data from a human volunteer, and the material properties of each element were determined. The model was validated using biomechanical data. A model that was implanted with SB Charite III® artificial discs via an anterior approach was also developed. The stresses and strains of the vertebral bodies and surrounding spinal ligaments were investigated. The implanted model was compared to the intact model in terms of range of motion, force on facet joints with flexion-exten- sion, lateral bending, and axial rotation under 400N preloading. Results: There were no significant differences between the findings of this finite element study and other reports in the literature. Our analytical method proved useful method for the biomechanical evaluation of the effects of artificial disc implan- tation. The implanted model revealed an increased range of motion in flexion-extension, lateral bending, and axial rotation compared to the intact model. The stresses on facets were greater in the implanted model than in the intact model. Conclusion: The model that was implanted with artificial discs showed increased segmental motion and stress on the facet joints compared to the intact model. We hypothesize that the removal of the anterior longitudinal ligament is the major cause of increased segmental motion and stress on the facet joints in the implanted model. The development of new artificial discs should focus on compensating for these unwanted results.

드롭착지 동작 시 체간모델에 따른 척추분절운동이 자세안정성 해석에 미치는 영향

유경석 ( Kyoung Seok Yoo ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.4

The purpose of this study was to assess the inter-segmental trunk motion during which multi-segmental movements of the spinal column was designed to interpret the effect of segmentation on the total measured spine motion. Also it analyzed the relative motion at three types of the spine models in drop landing. A secondary goal was to determine the intrinsic algorithmic errors of spine motion and the usefulness of such an approach as a tool to assess spinal motions. College students in the soccer team were selected the ten males with no history of spine symptoms or injuries. Each subject was given a fifteen minute adaptation period of drop landing on the 30cm height box. Inter-segmental spine motion were collected Vicon Motion Capture System (250 Hz) and synchronized with GRF data (1000 Hz). The result shows that Model III has a more increased range of motion (ROM) than Model I and Model II. And the Lagrange energy has significant difference of at E3 and E4 (p<.05). This study can be concluded that there are differences in the three models of algorithm during the phase of load absorption. Especially, Model III shows proper spine motion for the inter-segmental joint motion with the interaction effects using the seven segments. Model III shows more proper observed values about dynamic equilibrium than Model I & Model II. The findings have shown that the dynamic stability strategy of Model III toward multi-directional spinal motion supports for better function of the inter-segmental motor-control than the Model I and Model II.

A Trap Motion in Validating Muscle Activity Prediction from Musculoskeletal Model using EMG

Wibawa, A. D,Verdonschot, N,Halbertsma, J. P. K,Burgerhof, J. G. M,Diercks, R. L,Verkerke, G. J 보안공학연구지원센터 2016 International Journal of Bio-Science and Bio-Techn Vol.8 No.6

Musculoskeletal modeling nowadays is becoming the most common tool for studying and analyzing human motion. Besides its potential in predicting muscle activity and muscle force during active motion, musculoskeletal modeling can also calculate many important kinetic data that are difficult to measure in vivo, such as joint force or ligament force. This paper will validate muscle activity predicted by the model during a static motion like knee flexion motion (squat motion). In this experiment, knee flexion motion was performed by 5 healthy subjects and modeled by using Gait Lower Extremity model from AnyBody Modeling System (AMS). Eight lower limb muscle activity prediction from the model will be validated by 8 EMG electrodes that measured the same muscles during squat motion. Muscle activity pattern and the position of onset would be used as a key factor in this validation study. Pearson correlation coefficient will be used to compare the pattern of both graphs. Knee joint force prediction from the model will also be compared with the literature studies. The result showed that 3 muscles showed high correlation coefficient, while the other 4 muscles showed slightly medium and one showed low correlation. Time delay of muscle activation between the model and EMG was recorded from Vastus Medialis muscle (18.38 ms) and Vastus Lateralis (22.8 ms), with muscle activation from the model was late compared to EMG. In conclusion, this statistical study has shown some detail differences between EMG and muscle activity prediction from the model. Knee flexion motion can be used as a trap motion when validating muscle activity of a musculoskeletal model, because the model will activate muscle activity based on motion data of markers, while in knee-flexed position, there was no marker’s movement, but the EMG was highly active due to the posture of the subjects in maintaining the knee-flexed position. However, the knee compressive force prediction from the model has showed positive confirmation from the literatures.

지역좌표계에서 관측한 체간 척추분절운동에 관한 연구

유경석(KyoungSeokYoo),고영완(YoungWanKo),강진형(JinHyoungKang),서승우(SeungWooSuh) 한국체육학회 2013 한국체육학회지 Vol.52 No.6

본 연구는 지역좌표계로부터 체간척추 분절수 정의에 따른 One-Trunk (Model1), Upper-Lower Trunk (Model2), Multi-Segment Trunk (Model3) 모듈로 각각 정의하여 분절운동이 몸통체간운동에 미치는 영향을 연구하였다. 체간몸통운동 유형은 상체 앞으로 굽히기, 옆으로 굽히기, 몸통회전 3가지 동작으로 체간 척추세그먼트 운동의 관절가동범위인 각변위를 측정하였다. 실험대상자들은 6년 이상 축구경력이 있는 대학선수군(n=10)들로 하였다. 분석방법은 X-ray 분석과 3차원비디오영상분석을 하였으며, 측정장비는 적외선카메라 13대(250hz)를 이용한 바이콘모션캡쳐시스템(MX-T40)을 이용하였다. 자료처리는 SPSS(ver. 17) 일원변량분산분석을 하였으며 p<.05 유의수준에서 처리하였다. 분석결과 첫째, 체간 분절 수 증가에 따른 척추모델의 분절동작이 통계적으로 의미 있는 차이를 보였다. 사후검정결과 Model3과 Model2, 그리고 Model3과 Model1에서 모델그룹 간 유의한 차이가 나타났다. 둘째, X,Y,Z좌표축의 체간세그먼트 동작이 x, z축 상에서 통계적으로 유의한 차이를 보였다. 위의 결과를 종합해볼 때 Model3의 7개 세그먼트 움직임이 다양한 운동패턴으로 나타남으로서 인체운동특성에 의한 척추모듈이 권장되어야 할 것이다. The purpose of this study was to compare the effect of the three trunk spine segment models(One -Trunk Model, Upper-Lower Trunk Model, and Multi-Segment Trunk Model) by investigating the ROM of trunk segments from three-dimensional kinematic motion of the pelvis-spine coordinate system. To analyze the ROM of angular displacement on the trunk motion, The forward bending, the side bending, and the axial rotation were compared with the three types of trunk spine model, respectively. Ten male subjects were recruited as soccer players in university entrants. Three-dimensional video analysis and X-ray were performed. And Vicon Motion Capture System(MX-T40) using the thirteen infrared cameras(sampling frequency of 250Hz) and Vicon Nexus 1.7 software programs were used. Statistical process was to use SPSS(ver. 17), to do an one-way ANOVA and to do in significance level p<.05. Significant differences were noted in the trunk spine segment motion with trunk segments interaction effects using three kinematic trunk models between model, as well as between x, y, z축 coordinate system. It should therefore be chosen carefully because the trunk motion can be explained differently depending upon the module types in each trunk segment model, owing to, the number of trunk spine segments.

Measuring motion significance and motion complexity

Suh, I.H.,Lee, S.H.,Cho, N.J.,Kwon, W.Y. North-Holland [etc ; Elsevier Science Ltd 2017 Information sciences Vol.388 No.-

<P>In this paper, we propose two novel measures to specify motion significance and motion complexity from human motion trajectories. Motion significance indicates the relative meaningfulness of every motion frame which is defined as a set of data points acquired at a time index from multiple motion trajectories. Motion complexity indicates the number of meaningful motion frames involved in a set of such human motions. For this, we first show that motion significance can be measured by considering both temporal entropy and spatial entropy of a motion frame, based on the analysis of Gaussian mixtures learned from human motions. Motion complexity is then calculated by measuring the averaged amount of motion significance involved in all time indexes of motion trajectories. These two measures are devised to satisfy the requirement of neural complexity measure proposed to attain small values for totally random or totally regular activities. To show that the proposed measures are consistent with our intuitive notion of motion significance and motion complexity, several human motions for drawing and pouring are analyzed by means of motion significance and motion complexity. Furthermore, our complexity measure is compared with three existing complexity measures to analyze their similarity and dissimilarity. (C) 2017 Elsevier Inc. All rights reserved.</P>

단순인체모델 기반 휴머노이드의 인간형 전신동작 생성

김창환,김승수,나성권,유범재 한국로봇학회 2008 로봇학회 논문지 Vol.3 No.4

People have expected a humanoid robot to move as naturally as a human being does. The natural movements of humanoid robot may provide people with safer physical services and communicate with persons through motions more correctly. This work presented a methodology to generate the natural motions for a humanoid robot, which are converted from human motion capture data. The methodology produces not only kinematically mapped motions but dynamically mapped ones. The kinematical mapping reflects the human-likeness in the converted motions, while the dynamical mapping could ensure the movement stability of whole body motions of a humanoid robot. The methodology consists of three processes: (a) Human modeling, (b) Kinematic mapping and (c) Dynamic mapping. The human modeling based on optimization gives the ZMP (Zero Moment Point) and COM (Center of Mass) time trajectories of an actor. Those trajectories are modified for a humanoid robot through the kinematic mapping. In addition to modifying the ZMP and COM trajectories, the lower body (pelvis and legs) motion of the actor is then scaled kinematically and converted to the motion available to the humanoid robot considering dynamical aspects. The KIST humanoid robot, Mahru, imitated a dancing motion to evaluate the methodology, showing the good agreement in the motion.

Incremental Motion Learning through Kinesthetic Teachings and New Motion Production from Learned Motions by a Humanoid Robot

조수민,조성호 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.1

This work presents a new incremental motion learning algorithm through kinesthetic teachings and a new motion production algorithm by combining learned motions in a humanoid robot. The proposed algorithms are useful for improving the motions that a humanoid robot can produce. The learning algorithm consists of data encoding, time alignment, dimensional reduction, parameter estimation in the Gaussian mixture model (GMM) of motions, GMM refinement, and motion generation steps. The overall procedure is built to be incremental. No historic data memorization is required in any step,and model parameters are enough information to generate motions. The motion production algorithm allows a robot to extract new motions simply from learned motions without requiring teaching sessions. A series of experiments with a humanoid robot serves to validate the performance of the proposed algorithms.

Parameter identification of ship motion mathematical model based on full-scale trial data

Meng Yao,Zhang Xiufeng,Zhu Jinxin 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1

Using the full-scale trial data of vessel YUKUN, a parameter identification scheme, Support Vector Regression (SVR) combined with modified grey wolf optimizer (MGWO), is proposed for identifying ship motion model. This study establishes response mathematical model and 4 Degrees of Freedom (DOF) nonlinear whole-ship mathematical model of vessel YUKUN. The full-scale trial data of vessel YUKUN are processed and analyzed. In the study of grey box identification modeling, the rough parameters reference values of ship response mathematical model and nonlinear whole-ship mathematical model are obtained by SVR. Based on these rough reference values, the MGWO algorithm and Firefly Algorithm are used to further optimize them to obtain final parameter identification values. The final parameter identification values obtained by the three algorithms and recursive least squares with forgetting factor are substituted into the mathematical model to obtain the prediction results of ship motion state. The final prediction results of ship motion state show that the MGWO algorithm has strong search and optimization ability. In the case that the reference values obtained by SVR are not accurate, MGWO algorithm can be used to find accurate parameters of ship motion mathematical model in a given range. The proposed scheme provides a reference for the parameter identification of ship motion mathematical model.

시추공 관측소 계측 자료에 기반한 암반의 지반운동 모델 개발

강신항(Sinhang Kang) 한국암반공학회 2024 터널과지하공간 Vol.34 No.4

우리나라는 2016년 경주 지진과 2017년 포항 지진 이후 지진 재해 방지 대책의 필요성이 증가하고 있으며, 지진 피해 정량화를 위해 신뢰성 있는 지진 재해도 해석 기법과 지반운동 모델이 요구된다. 최근 심층 지하 시설에 대한 수요가 증가하고 있다. 이에 따라 지하 암반층에서의 지진 재해 정량화 기법의 정확성 확보가 필요하다. 본 연구에서는 국내 시추공 관측소에서 계측된 지반운동 자료를 활용하여 지하 암반층에서의 지반운동을 예측할 수 있는 모델을 제안하였다. 스펙트럴 가속도의 0.01~10초 주기 중 17개를 대상으로 경험적 기법 중 회귀분석을 적용하여 지반운동 모델을 개발하였다. 지반운동 모델의 예측 성능을 평가 및 개선하기 위해 잔차 분석을 수행하고, 보정 인자를 모델식에 추가하였다. 제안된 모델을 적용하였을 때 잔차의 구간 평균이 0에 근접하였고, 기존 국외 모델들과 유사한 종합 잔차의 표준편차를 확인함으로써 제안된 모델의 신뢰성을 확인하였다. In South Korea, following the 2016 Gyeongju and 2017 Pohang earthquakes, the need for earthquake disaster prevention has been increasing. Reliable techniques for probabilistic seismic hazard analysis and ground motion models are required for quantifying earthquake damage. Recently, there has been growing demand for deep underground facilities, necessitating accurate quantification techniques for earthquake damage in deep underground. In this study, ground motion models within rock were proposed using ground motion data measured at borehole seismic stations. A regression analysis, a type of empirical technique, was applied to 17 periods selected in a range from 0.01 to 10 s of spectral accelerations to develop the ground motion models. Residual analysis was performed to evaluate and improve the prediction performance of the ground motion model, with correction factors added to the model equation. When applying the proposed model, the group means of residuals approached zero, and the standard deviation of total residuals, similar to existing models proposed in other countries, confirmed the reliability of the proposed model.

Verification and improvement of dynamic motion model in MARS for marine reactor thermal-hydraulic analysis under ocean condition

범희관,김건우,박군철,조형규 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.5

Unlike land-based nuclear power plants, a marine or floating reactor is affected by external forces due toocean conditions. These external forces can cause additional accelerations and affect each system andequipment of the marine reactor. Therefore, in designing a marine reactor and evaluating its performanceand stability, a thermal hydraulic safety analysis code is necessary to consider the thermal hydrodynamiceffects of ship motion. MARS, which is a reactor system analysis code, includes a dynamicmotion model that can simulate the thermal-hydraulic phenomena under three-dimensional motion bycalculating the body force term included in the momentum equation. In this study, it was verified thatthe dynamic motion model can simulate fluid motion with reasonable accuracy using conceptualproblems. In addition, two modifications were made to the dynamic motion model; first, a user-suppliedtable to simulate a realistic ship motion was implemented, and second, the flow regime map determinationalgorithm was improved by calculating the volume inclination information at every time step ifthe dynamic motion model was activated. With these modifications, MARS could simulate the thermalhydraulicphenomena under ocean motion more realistically.