小波变换和分形理论在脉象识别中的应用

提出基于小波变换的多尺度空间能量分布特征提取方法,和利用分形理论提取的分数维,并作为波形的重要特征,可以用于脉象分类识别.最后,利用这些特征矢量和BP神经网络对实测的脉象数据进行了分类,取得了令人满意的分类正确率.与频域分析参数识别的方法相比较,小波变换和盒维数方法更简单易行.     

Local-homogeneity-based global continuous control for mechanical systems with constrained inputs: finite-time and exponential stabilisation

A global continuous control scheme for the finite-time or (local) exponential stabilisation of mechanical systems with constrained inputs is proposed. The approach is formally developed within the theoretical framework of local homogeneity. This has permitted to solve the formulated problem not only guaranteeing input saturation avoidance but also giving a wide range of design flexibility. The proposed scheme is characterised by a saturating-proportional-derivative type term with generalised saturating and locally homogeneous structure that permits multiple design choices on both aspects. The work includes a simulation implementation section where the veracity of the so-cited argument claiming that finite-time stabilisers are faster than asymptotical ones is studied. In particular, a way to carry out the design so as to, indeed, guarantee faster stabilisation through finite-time controllers (beyond their finite-time convergence) is shown.     

Hybrid position/force tracking for a class of constrained mechanical systems

We study the hybrid tracking problem for a class of mechanical systems, described by Euler-Lagrange equations of motion, subject to a set of holonomic and/or nonholonomic constraints in a unified fashion. Based on a QR-like decomposition of the constraint Jacobian, it is shown that the constraint-force free and reduced constrained motions of constrained mechanical systems can be naturally separated. A new hybrid control is proposed for the decomposed motions to achieve simultaneous, independent position and force tracking. Some comments about the applicability of main tracking result are given.     

用flip变换法恢复四面体网格中的约束边

本文介绍了约束四面体网格生成中的一种恢复约束边的方法——flip变换法。即首先找到所有被约束边穿过的三角形面，然后依次对这些面执行flip23变换，以此实现约束边的恢复。     

On the transformation of nonlinear dynamical systems into the extended nonlinear observable canonical form

This article deals with the transformation of a class of nonlinear systems into an extended nonlinear observable canonical form (ENOCF) by dynamic extension. The dynamic extension is obtained by adding auxiliary dynamics and virtual outputs to the original system, thus giving rise to a higher dimensional system in an extended state space. Sufficient geometrical conditions to guarantee the existence of a local diffeomorphism which allow the transformation of the extended system into the ENOCF are given. In particular, an algorithm that permits us to compute such a diffeomorphism is derived.     

Feedback diagonal canonical form and its application to stabilization of nonlinear systems

~~Feedback diagonal canonical form and its application to stabilization of nonlinear systems1. Aeyels, D., Stabilization of a class of non-linear systems by a smooth feedback control, Sys. Contr. Lett., 1985, 5: 289-294. 2. Behtash, S., Dastry, D., Stabilization of non-linear systems with uncontrollable linearization, IEEE Trans. Aut. Contr., 1988, 33(6): 585-590. 3. Byrnes, C. I., Isidori, A., Willems, J. C., Passivity, feedback equivalence, and the global stabilization of …     

Modelling worker fatigue and recovery in dual-resource constrained systems

The operational benefits that dual-resource constrained (DRC) job shop systems bring have captured the attention of researchers for some time. Although several studies that investigate DRCs are available in the literature, none has investigated a DRC system for the effects of human fatigue and recovery, which poses important parameters to avoiding overload and injury to employees. The purpose of this paper is to address this limitation by presenting a mixed-integer linear programming (MILP) model that describes fatigue and recovery in a DRC system with one worker performing n tasks (flexibility level) within m cycles. Later, the complexity of the MILP problem was reduced to four practical cases. These cases were investigated to evaluate several research questions. The results obtained from the MILP model and the four practical cases suggest that short rest breaks after each task, short cycle times and faster recovery rates improve the system’s performance and that reduced force levels in the work tasks will reduce recovery needs and further increase performance. Further research is still needed to identify or to develop better models of physiological and mental fatigue that can be integrated to the modelling framework presented here.     

Hamilton系统的保辛 守恒积分算法

给出了Hamilton系统基于辛矩阵乘法的显式时不变正则变换和时变正则变换．引入含参变量的近似Hamilton系统,并以近似Hamilton系统为基础进行辛矩阵乘法的正则变换．正则变换保证了数值积分的保辛性质,而通过调整引入的参变量可保证能量在积分格点上守恒．实现了Hamilton系统即保辛又保能量的算法．     

Stability,positive invariance and design of constrained regulators for networked control systems

In this article, the stability analysis, the positive invariance of polyhedral sets and the design of state-feedback regulators for networked control systems (NCS) with bounded transmission delays, constant and unknown or time-varying, are investigated. The dynamics of the NCS is described by autoregressive-moving-average (ARMA) models. Contrary to former approaches based on quadratic Lyapunov functions, in this article polyhedral Lyapunov functions are used for both stability and positive invariance analysis and state-feedback synthesis. Then, based on the property that the exponential of a matrix can be expressed as a weighted sum of its constituent matrices, it is proven that the problems of determination of stability margins or the design of stabilising controllers can be reduced to linear programming optimisation problems. The use of ARMA models allows the development of methods for the design of state-feedback controllers satisfying state constraints or convergence rate specifications defined on the NCS state space and not on the state of an augmented state space representation.     

离散约束系统最优控制中的内点法

对于带约束的力学系统的最优控制,约束系统离散力学最优控制（Discrete Mechanics and Optimal Control for Constrained Systems,DMOCC）采用了“先离散,后变分”的方法,结合离散零空间法,能很好地保持系统的物理特性,其模型方程可表示为非线性等式约束的优化问题,通常采用标准序列二次规划（Sequence Quadratic Program,SQP）算法求解。由于约束条件的规模大,SQP算法的计算效率不高。相对于SQP,内点法具有收敛性好、稳定性强的特点。在对DMOCC约束条件的特点进行分析之后,将内点法用于DMOCC的数学模型进行数值计算,能有效提高计算效率。曲柄滑块的数值仿真证明了在数值精度一致的情况下,内点法具有效率上的优势。