Continuous and discrete zeroing dynamics models using JMP function array and design formula for solving time-varying Sylvester-transpose matrix inequality

Numerical Algorithms - Zeroing dynamics (ZD) has shown great performance to solve various time-varying problems. In this paper, the problem of time-varying Sylvester-transpose matrix inequality is...     

New zeroing neural dynamics models for diagonalization of symmetric matrix stream

Numerical Algorithms - In this paper, the problem of diagonalizing a symmetric matrix stream (or say, time-varying matrix) is investigated. To fulfill our goal of diagonalization, two error...     

Continuous and discrete time Zhang dynamics for time-varying <Emphasis Type="Italic">4</Emphasis>th root finding

Recently, a special class of neural dynamics has been proposed by Zhang et al. for online solution of time-varying and/or static nonlinear equations. Different from eliminating a square-based positive error-function associated with gradient-based dynamics (GD), the design method of Zhang dynamics (ZD) is based on the elimination of an indefinite (unbounded) error-function. In this paper, for the purpose of online solution of time-varying 4th root, both continuous-time ZD (CTZD) and discrete-time ZD (DTZD) models are developed and investigated. In addition, power-sigmoid activation function is exploited in Zhang dynamics, which makes ZD models possess the property of superior convergence and better accuracy. To summarize generalization for possible widespread application, such approach is further extended to general time-varying nonlinear equations solving. Computer-simulation results demonstrate the efficacy of the ZD models for finding online time-varying 4th root and solving general time-varying equations.     

Effective parameter range for equivalence of velocity-level and acceleration-level redundancy resolution schemes

This Letter shows the equivalence of the velocity-level and acceleration-level redundancy resolution schemes by using so-called Zhang et al.?s neural-dynamic method. In addition, the equivalence requires that a design parameter be sufficiently large. But how large should it be? The effective range of such a design parameter is thus determined by means of the 2%-difference rule and the runtime of the computer-simulations.     

基于混合左右手和人工传输线的平面双定向耦合器

利用人工传输线作为右手传输线,与混合左右手传输线(CRLH-TL)进行耦合,实现左手传输线和右手传输线的混合耦合,构造了一种新型的定向耦合器。该耦合器具有后向耦合、小型化、结构紧凑的特点。实验测试结果表明:耦合器的工作频率在1.3~1.8 GHz,相对百分比带宽达到32%,实现了10 dB的耦合度,比常规微带线定向耦合器具有更大的耦合度调节范围,隔离度大于25 dB。实验测试结果与电磁仿真结果相吻合。     

基于3个误差函数的复数ZNN模型求解复数满秩矩阵的Moore-Penrose逆

针对复数满秩矩阵的Moore Penrose逆问题,采用一种新型的递归神经网络(ZNN)进行求解.构造3个不同的复数矩阵误差函数,利用ZNN设计公式推导得到对应的不同复数ZNN模型.为了便于计算机仿真,采用向量化技术将所得到的ZNN模型由矩阵形式转换为矩阵向量形式.计算机仿真结果表明了所得到的3个复数ZNN模型在求解复数满秩矩阵Moore Penrose逆时的可行性与有效性.     

Solving time-varying inverse kinematics problem of wheeled mobile manipulators using Zhang neural network with exponential convergence

A mobile manipulator is a robotic device composed of a mobile platform and a stationary manipulator fixed to the platform. The forward kinematics problem for such mobile manipulators has a mathematical analytic solution; however, the inverse kinematics problem is mathematically intractable (especially for satisfying real-time requirements). To obtain the accurate solution of the time-varying inverse kinematics for mobile manipulators, a special class of recurrent neural network, named Zhang neural network (ZNN), is exploited and investigated in this article. It is theoretically proven that such a ZNN model globally and exponentially converges to the solution of the time-varying inverse kinematics for mobile manipulators. In addition, the kinematics equations of the mobile platform and the manipulator are integrated into one system, and thus the resultant solution can co-ordinate simultaneously the wheels and the manipulator to fulfill the end-effector task. For comparison purposes, a gradient neural network (GNN) is developed for solving time-varying inverse kinematics problem of wheeled mobile manipulators. Finally, we conduct extensive tracking-path simulations performed on a wheeled mobile manipulator using such a ZNN model. The results substantiate the efficacy and high accuracy of the ZNN model for solving time-varying inverse kinematics problem of mobile manipulators. Besides, by comparing the simulation results of the GNN and ZNN models, the superiority of the ZNN model is demonstrated clearly.     

Dansylation isotope labeling liquid chromatography mass spectrometry for parallel profiling of human urinary and fecal submetabolomes

Human urine and feces can be non-invasively collected for metabolomics-based disease biomarker discovery research. Because urinary and fecal metabolomes are thought to be different, analysis of both biospecimens may generate a more comprehensive metabolomic profile that can be better related to the health state of an individual. Herein we describe a method of using differential chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS) for parallel metabolomic profiling of urine and feces. Dansylation labeling was used to quantify the amine/phenol submetabolome changes among different samples based on ¹²C-labeling of individual samples and ¹³C-labeling of a pooled urine or pooled feces and subsequent analysis of the ¹³C-/¹²C-labeled mixture by LC-MS. The pooled urine and pooled feces are further differentially labeled, mixed and then analyzed by LC-MS in order to relate the metabolite concentrations of the common metabolites found in both biospecimens. This method offers a means of direct comparison of urinary and fecal submetabolomes. We evaluated the analytical performance and demonstrated the utility of this method in the analysis of urine and feces collected daily from three healthy individuals for 7 days. On average, 2534 ± 113 (n = 126) peak pairs or metabolites could be detected from a urine sample, while 2507 ± 77 (n = 63) peak pairs were detected from a fecal sample. In total, 5372 unique peak pairs were detected from all the samples combined; 3089 and 3012 pairs were found in urine and feces, respectively. These results reveal that the urine and fecal metabolomes are very different, thereby justifying the consideration of using both biospecimens to increase the probability of finding specific biomarkers of diseases. Furthermore, the CIL LC-MS method described can be used to perform parallel quantitative analysis of urine and feces, resulting in more complete coverage of the human metabolome.     

Simultaneous repetitive motion planning of two redundant robot arms for acceleration-level cooperative manipulation

This Letter proposes a novel simultaneous repetitive motion planning (SRMP) scheme of two redundant robot arms for cooperative manipulation. To remedy the joint-angle drift phenomenon, two SRMP subschemes are exploited at the joint-acceleration level. The subschemes are then simultaneously reformulated as two quadratic programs (QPs), which are finally unified into a QP problem solving. Theoretical analysis and computer simulation based on two three-link robot arms both substantiate the feasibility and effectiveness of the proposed SRMP scheme.