Posture recognition plays an important role in many applications,such as security system and monitoring system.Joint quaternion combined with support vector machine(SVM) can solve the problem of moving human posture r...Posture recognition plays an important role in many applications,such as security system and monitoring system.Joint quaternion combined with support vector machine(SVM) can solve the problem of moving human posture recognition.It is a simple and effective algorithm that only three joints are used as the feature points in the whole human skeleton.Using the quaternion of the three joints,a feature vector with five parameters in gait cycle is extracted.The efficiency of the proposed method is demonstrated through an experimental study,and walking and running postures can be distinguished accurately.展开更多
The exponential weighted moving average technique used in process mean and variance monitoring charts was combined by Gan in 1997 and proposed two combined joint monitoring schemes one with rectangular control region ...The exponential weighted moving average technique used in process mean and variance monitoring charts was combined by Gan in 1997 and proposed two combined joint monitoring schemes one with rectangular control region and the other with elliptical control region. Performance of these two schemes may very depend on the shifts in mean or variance to be detected quickly. In this paper, performances of these two schemes are evaluated with respect to the average run length properties. The results reveal that elliptical scheme is little faster in detecting the shifts in process mean and increase in variance within a limit.展开更多
基金the Key Project of the National Natural Science Foundation of China(No.61134009)National Natural Science Foundations of China(Nos.61473077,61473078,61503075)+6 种基金Cooperative Research Funds of the National Natural Science Funds Overseas and Hong Kong and Macao Scholars,China(No.61428302)Program for Changjiang Scholars from the Ministry of Education,ChinaSpecialized Research Fund for Shanghai Leading Talents,ChinaProject of the Shanghai Committee of Science and Technology,China(No.13JC1407500)Innovation Program of Shanghai Municipal Education Commission,China(No.14ZZ067)Shanghai Pujiang Program,China(No.15PJ1400100)the Fundamental Research Funds for the Central Universities,China(Nos.15D110423,2232015D3-32)
文摘Posture recognition plays an important role in many applications,such as security system and monitoring system.Joint quaternion combined with support vector machine(SVM) can solve the problem of moving human posture recognition.It is a simple and effective algorithm that only three joints are used as the feature points in the whole human skeleton.Using the quaternion of the three joints,a feature vector with five parameters in gait cycle is extracted.The efficiency of the proposed method is demonstrated through an experimental study,and walking and running postures can be distinguished accurately.
文摘The exponential weighted moving average technique used in process mean and variance monitoring charts was combined by Gan in 1997 and proposed two combined joint monitoring schemes one with rectangular control region and the other with elliptical control region. Performance of these two schemes may very depend on the shifts in mean or variance to be detected quickly. In this paper, performances of these two schemes are evaluated with respect to the average run length properties. The results reveal that elliptical scheme is little faster in detecting the shifts in process mean and increase in variance within a limit.
文摘目的探究动态膝外翻(dynamic knee valgus,DKV)女性在跑步着地阶段的动态稳定性与刚度特征,揭示动态稳定性与关节刚度之间的联系,为DKV女性的损伤预防和康复提供理论依据和实践参考。方法根据膝外翻角度进行组别划分,膝外翻角超过13°为DKV组(n=16),膝外翻角0°~13°为正常人群组(n=16)。采用三维动作捕捉系统、三维测力台和无线表面肌电系统测量跑步时运动学、动力学及肌电数据,计算动态稳度(margin of stability,MoS)、关节刚度与肌电指标,并进行组间差异性检验和相关性分析。结果与正常女性相比,DKV女性矢状面膝关节峰值力矩、冠状面膝关节角度变化量均较大(P<0.05);DKV女性冠状面MoS、膝关节刚度、踝关节刚度均较小(P<0.05)。着地前,DKV女性臀中肌、股外侧肌的肌肉预激活程度低于正常女性(P<0.05),腓肠肌外侧肌的预激活程度高于正常女性(P<0.01);着地后,DKV女性髋关节周围肌肉共激活比高于正常女性(P<0.01);正常女性冠状面MoS与冠状面髋关节刚度之间存在高度负相关(r=-0.634,P=0.048);DKV女性冠状面MoS与冠状面髋关节刚度(r=-0.600,P=0.042)、矢状面踝关节刚度(r=-0.673,P=0.024)呈高度负相关。结论跑步时,DKV女性在冠状面表现出动态稳定性下降和膝、踝关节刚度不足的特征,存在潜在损伤风险;为代偿近端关节的控制不足,DKV女性在着地前会增加远端关节肌肉的激活程度,以防止冠状面动态稳定性及膝、踝关节刚度进一步下降。DKV女性跑步时动态稳定性与关节刚度存在高度负相关,当身体在冠状面处于不稳定状态时,通过提高矢状面踝关节刚度和冠状面髋关节刚度以维持身体整体稳定性。
