This work presents a controller designed for position-controlled quadrupedal dynamic locomotion,aiming at simple and robust trotting control. The controller takes the torso attitude angles and velocities into planning...This work presents a controller designed for position-controlled quadrupedal dynamic locomotion,aiming at simple and robust trotting control. The controller takes the torso attitude angles and velocities into planning foot trajectories. Firstly design of the servo motor actuated quadruped robot is introduced and the kinematic equations are deduced. Then a scheme is presented for controlling the robot torso attitude based on the virtual leg model. Furthermore,it demonstrates the design of the controller which enables the robot to have a wide range of trotting gaits and omni-directional motions. Finally,results of robust trotting in various speeds,path tracking and push recovery in simulation are reported,and results of trotting on real quadruped robots will be studied.展开更多
A novel two-dimensional (2D) simulation method of positive corona current pulses is proposed. A control-volume- based finite element method (CV-FEM) is used to solve continuity equations, and the Galerkin finite e...A novel two-dimensional (2D) simulation method of positive corona current pulses is proposed. A control-volume- based finite element method (CV-FEM) is used to solve continuity equations, and the Galerkin finite element method (FEM) is used to solve Poisson's equation. In the proposed method, photoionization is considered by adopting an exact Helmholtz photoionization model. Furthermore, fully implicit discretization and variable time step are used to ensure the time-efficiency of the present method. Finally, the method is applied to a positive rod-plane corona problem. The numerical results are in agreement with the experimental results, and the validity of the proposed method is verified.展开更多
This paper discusses the singular ( n\|1,1 ) conjugate boundary value problem as follows by using a fixed point index theorem in cones[HL(2:1,Z;2,Z]u (n) (t)+a(t)f(u(w(t)))=0,(0<t<1), u(t)=φ(t),(-τ≤t&l...This paper discusses the singular ( n\|1,1 ) conjugate boundary value problem as follows by using a fixed point index theorem in cones[HL(2:1,Z;2,Z]u (n) (t)+a(t)f(u(w(t)))=0,(0<t<1), u(t)=φ(t),(-τ≤t<0), u (j) (0)=u(1)=0,(1≤j≤n-2).Effort is devoted to give some sufficient conditions for which the equation has at least two positive solutions.An example to illustrate the application of this theorem is given. [FQ(6*2。39,X-W]展开更多
OBJECTIVE: This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hallucination of patients with schizophrenia spectrum disorders. DATA SOURCES: O...OBJECTIVE: This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hallucination of patients with schizophrenia spectrum disorders. DATA SOURCES: Online literature retrieval was conducted using PubMed, ISI Web of Science, EMBASE, Medline and Cochrane Central Register of Controlled Trials databases from January 1985 to May 2012. Key words were "transcranial magnetic stimulation", "TMS", "repetitive tran- scranial magnetic stimulation", and "hallucination". STUDY SELECTION: Selected studies were randomized controlled trials assessing therapeutic ef- ficacy of repetitive transcranial magnetic stimulation for hallucination in patients with schizophrenia spectrum disorders. Experimental intervention was low-frequency repetitive transcranial magnetic stimulation in left temporoparietal cortex for treatment of auditory hallucination in schizophrenia spectrum disorders. Control groups received sham stimulation. MAIN OUTCOME MEASURES: The primary outcome was total scores of Auditory Hallucinations Rating Scale, Auditory Hallucination Subscale of Psychotic Symptom Rating Scale, Positive and Negative Symptom Scale-Auditory Hallucination item, and Hallucination Change Scale. Secondary outcomes included response rate, global mental state, adverse effects and cognitive function. RESULTS: Seventeen studies addressing repetitive transcranial magnetic stimulation for treatment of schizophrenia spectrum disorders were screened, with controls receiving sham stimulation. All data were completely effective, involving 398 patients. Overall mean weighted effect size for repeti- tive transcranial magnetic stimulation versus sham stimulation was statistically significant (MD = -0.42, 95%C/: -0.64 to -0.20, P = 0.000 2). Patients receiving repetitive transcranial magnetic stimulation responded more frequently than sham stimulation (OR = 2.94, 95%C/: 1.39 to 6.24, P =0.005). No significant differences were found between active repetitive transcranial magnetic stimulation and sham stimulation for positive or negative symptoms. Compared with sham stimulation, active repeti- tive transcranial magnetic stimulation had equivocal outcome in cognitive function and commonly caused headache and facial muscle twitching. CONCLUSION: Repetitive transcranial magnetic stimulation is a safe and effective treatment for auditory hallucination in schizophrenia spectrum disorders,展开更多
Understanding of the basic properties of the positive semi-definite tensor is a prerequisite for its extensive applications in theoretical and practical fields, especially for its square-root. Uniqueness of the square...Understanding of the basic properties of the positive semi-definite tensor is a prerequisite for its extensive applications in theoretical and practical fields, especially for its square-root. Uniqueness of the square-root of a positive semi-definite tensor is proven in this paper without resorting to the notion of eigenvalues, eigenvectors and the spectral decomposition of the second-order symmetric tensor.展开更多
为了提升分布式传感器场景下对于宽带辐射源的定位效果,本文提出了一种基于到达时间差(Time Difference Of Arrival,TDOA)的多频率聚焦与融合的相干辐射源直接定位(Direct Position Determination,DPD)方法 .首先,对衰减系数未知的传感...为了提升分布式传感器场景下对于宽带辐射源的定位效果,本文提出了一种基于到达时间差(Time Difference Of Arrival,TDOA)的多频率聚焦与融合的相干辐射源直接定位(Direct Position Determination,DPD)方法 .首先,对衰减系数未知的传感器时域接收信号进行预处理,进行数据分段和频域变换,将宽带信号转化成若干个多快拍窄带频域信号;其次,根据最佳聚焦矩阵构造准则,构造聚焦矩阵,将各频率对应的信号聚焦到中心频率附近频谱能量最大的聚焦频率,得到聚焦后的接收数据;然后,根据子空间正交性建立关于辐射源位置的最小化代价函数,融合多个聚焦后的代价函数解决衰减系数未知的问题;最后,结合拉格朗日乘子法,通过网格点上代价函数值的谱峰搜索得到宽带辐射源的估计位置.所提方法可以在衰减系数未知的情况下实现相干辐射源的高精度定位,仿真和实际测试结果表明本文所提方法的有效性,在信噪比大于0 dB的四节点多径定位场景中,所提方法的定位性能较其他时差直接定位性能提升了30%以上.展开更多
基金Supported by the National Natural Science Foundation of China(No.61233014,61305130)China Postdoctoral Science Foundation(No.2013M541912)the Shandong Provincial Natural Science Foundation(No.ZR2013FQ003,ZR2013EEM027)
文摘This work presents a controller designed for position-controlled quadrupedal dynamic locomotion,aiming at simple and robust trotting control. The controller takes the torso attitude angles and velocities into planning foot trajectories. Firstly design of the servo motor actuated quadruped robot is introduced and the kinematic equations are deduced. Then a scheme is presented for controlling the robot torso attitude based on the virtual leg model. Furthermore,it demonstrates the design of the controller which enables the robot to have a wide range of trotting gaits and omni-directional motions. Finally,results of robust trotting in various speeds,path tracking and push recovery in simulation are reported,and results of trotting on real quadruped robots will be studied.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB209402)the National Natural Science Foundation of China(Grant No.51177041)the Fundamental Research Funds for the Central Universities,China(Grant No.12QX01)
文摘A novel two-dimensional (2D) simulation method of positive corona current pulses is proposed. A control-volume- based finite element method (CV-FEM) is used to solve continuity equations, and the Galerkin finite element method (FEM) is used to solve Poisson's equation. In the proposed method, photoionization is considered by adopting an exact Helmholtz photoionization model. Furthermore, fully implicit discretization and variable time step are used to ensure the time-efficiency of the present method. Finally, the method is applied to a positive rod-plane corona problem. The numerical results are in agreement with the experimental results, and the validity of the proposed method is verified.
基金Supported by the NSF of Guangdong Province!( 980 0 1 8) Higher Education Bureau!( 1 99873)
文摘This paper discusses the singular ( n\|1,1 ) conjugate boundary value problem as follows by using a fixed point index theorem in cones[HL(2:1,Z;2,Z]u (n) (t)+a(t)f(u(w(t)))=0,(0<t<1), u(t)=φ(t),(-τ≤t<0), u (j) (0)=u(1)=0,(1≤j≤n-2).Effort is devoted to give some sufficient conditions for which the equation has at least two positive solutions.An example to illustrate the application of this theorem is given. [FQ(6*2。39,X-W]
基金Supported by the National High Technology Research and Development Programme of China ( No. 2004AA001210) and the National Natural Science Foundation of China (No. 60532030).
基金financially sponsored by the Special Funding of Henan Health Science and Technology Innovation Talent Project,No.4173(2010-2015)Xinxiang Medical University of High-Level Personnel of Scientific Research Projects,No.08BSKYQD-004the Key Projects of Science and Technology Research of Department of Education in Henan,No.13A320869
文摘OBJECTIVE: This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hallucination of patients with schizophrenia spectrum disorders. DATA SOURCES: Online literature retrieval was conducted using PubMed, ISI Web of Science, EMBASE, Medline and Cochrane Central Register of Controlled Trials databases from January 1985 to May 2012. Key words were "transcranial magnetic stimulation", "TMS", "repetitive tran- scranial magnetic stimulation", and "hallucination". STUDY SELECTION: Selected studies were randomized controlled trials assessing therapeutic ef- ficacy of repetitive transcranial magnetic stimulation for hallucination in patients with schizophrenia spectrum disorders. Experimental intervention was low-frequency repetitive transcranial magnetic stimulation in left temporoparietal cortex for treatment of auditory hallucination in schizophrenia spectrum disorders. Control groups received sham stimulation. MAIN OUTCOME MEASURES: The primary outcome was total scores of Auditory Hallucinations Rating Scale, Auditory Hallucination Subscale of Psychotic Symptom Rating Scale, Positive and Negative Symptom Scale-Auditory Hallucination item, and Hallucination Change Scale. Secondary outcomes included response rate, global mental state, adverse effects and cognitive function. RESULTS: Seventeen studies addressing repetitive transcranial magnetic stimulation for treatment of schizophrenia spectrum disorders were screened, with controls receiving sham stimulation. All data were completely effective, involving 398 patients. Overall mean weighted effect size for repeti- tive transcranial magnetic stimulation versus sham stimulation was statistically significant (MD = -0.42, 95%C/: -0.64 to -0.20, P = 0.000 2). Patients receiving repetitive transcranial magnetic stimulation responded more frequently than sham stimulation (OR = 2.94, 95%C/: 1.39 to 6.24, P =0.005). No significant differences were found between active repetitive transcranial magnetic stimulation and sham stimulation for positive or negative symptoms. Compared with sham stimulation, active repeti- tive transcranial magnetic stimulation had equivocal outcome in cognitive function and commonly caused headache and facial muscle twitching. CONCLUSION: Repetitive transcranial magnetic stimulation is a safe and effective treatment for auditory hallucination in schizophrenia spectrum disorders,
文摘Understanding of the basic properties of the positive semi-definite tensor is a prerequisite for its extensive applications in theoretical and practical fields, especially for its square-root. Uniqueness of the square-root of a positive semi-definite tensor is proven in this paper without resorting to the notion of eigenvalues, eigenvectors and the spectral decomposition of the second-order symmetric tensor.
文摘为了提升分布式传感器场景下对于宽带辐射源的定位效果,本文提出了一种基于到达时间差(Time Difference Of Arrival,TDOA)的多频率聚焦与融合的相干辐射源直接定位(Direct Position Determination,DPD)方法 .首先,对衰减系数未知的传感器时域接收信号进行预处理,进行数据分段和频域变换,将宽带信号转化成若干个多快拍窄带频域信号;其次,根据最佳聚焦矩阵构造准则,构造聚焦矩阵,将各频率对应的信号聚焦到中心频率附近频谱能量最大的聚焦频率,得到聚焦后的接收数据;然后,根据子空间正交性建立关于辐射源位置的最小化代价函数,融合多个聚焦后的代价函数解决衰减系数未知的问题;最后,结合拉格朗日乘子法,通过网格点上代价函数值的谱峰搜索得到宽带辐射源的估计位置.所提方法可以在衰减系数未知的情况下实现相干辐射源的高精度定位,仿真和实际测试结果表明本文所提方法的有效性,在信噪比大于0 dB的四节点多径定位场景中,所提方法的定位性能较其他时差直接定位性能提升了30%以上.