Daubechies复小波的生成及其在短时电能质量扰动检测中的应用

在分析比较了现有用于短时电能质量扰动检测的方法后,研究了用正交紧支复小波进行检测与抑制噪声的原理,提出用Daubechies正交紧支实小波派生其复小波的实用方法,并结合复小波变换提供的相位信息构造了多种新型复合信息形式.仿真表明,采用本文方法派生的复小波及其复合信息形式进行电能质量扰动检测,具有良好的噪声鲁棒性且提高了应用Mallat算法的实时性.     

一种欠驱动船舶编队滑模鲁棒控制方法

为实现模型参数不确定和外界风浪流干扰情况下的欠驱动水面船舶编队控制,提出一种跟随者仅利用领航船的位置及航向信息,而不利用领航船的速度、角速度和动力学信息的编队控制方法.根据领航船的位置及航向角信息设计虚拟船,使其轨迹与参考船在有限时间内重合;基于虚拟船策略建立领导-跟随模式下的船舶编队控制模型;将反步法与滑模变结构方法相结合,设计了一种可以有效处理模型参数摄动和外界环境干扰问题的鲁棒控制器,使得跟随船沿着虚拟船的轨迹运动,从而与领航者保持期望的队形,达到编队控制的目的.通过对由3只“Northern Clipper”实船所组成的船舶编队进行编队控制仿真实验,结果验证了所提方法的正确性和有效性.     

无创神经调控技术对全麻患者术后睡眠功能紊乱影响的研究进展

无创神经调控技术是主要通过电刺激、磁刺激等对神经功能状态进行调控的一种非侵入性、安全、便捷的有效治疗手段。近年来,无创神经调控技术越来越多地被用于脑功能调控的相关研究和治疗,其在脑卒中患者的认知障碍调控、抑郁、焦虑、谵妄、失眠等神经精神疾病的治疗上都有相关研究证实。临床科室如神经内科、康复科、疼痛科等多学科都广泛运用无创神经调控这一技术,但其在围术期的应用较少,尤其是针对全麻患者术后睡眠功能紊乱的研究尚未见报道。术后睡眠功能紊乱是术后一个常见且容易被忽视的并发症,常表现为术后睡眠结构紊乱、睡眠质量下降、睡眠时长明显缩短等,全身麻醉患者术后睡眠功能更容易受影响。术后睡眠功能紊乱涉及术前、术中以及术后等很多影响因素,影响患者整个围术期甚至出院后的长期预后。     

电离层垂直探测中扰动观测模式研究

电离层高频反射回波的多普勒频移观测是研究电离层扰动的一个重要方法.利用电离层垂直探测中的组合脉冲控制和回波相位测量分析方法,开发并实现了一种电离层扰动观测模式.实验观测表明,新开发的观测模式在电离层高频反射回波为窄带信号的情况下,可实时获得高精度多普勒频高图,并给出电离层扰动速度的时空变化曲线,能够满足电离层扰动观测研究的需要.     

Hybrid modelling of machine tool axis drives

The x-axis dynamics of a milling machine where the workpiece and saddle are mounted on supporting slides is considered. A permanent magnet motor, lead screw, ball nut and bearings are employed as the machine, traverse actuator mechanism. Hybrid, distributed–lumped parameter methods are used to model the machine tool x-axis drive system. Inclusion of the spatial configuration of the drive generates the incident, travelling and reflected vibration signature of the system. Lead screw interactive torsion and tension loading, which is excited by cutting and input disturbance conditions, is incorporated in the modelling process. Measured and results from simulation exercises are presented in comparative studies enabling the dynamic characteristics of the machine to be identified under, no load and with the application of cyclic, cutting force disturbances. The effect of the lead screw length, cutting speed and hence the load disturbance frequency are examined and the resulting performance accuracy is commented upon.     

Stability of formal thought disorder and referential communication disturbances in schizophrenia.

This study examined the degree to which different types of communication disturbances in the speech of 48 schizophrenia patients and 28 controls were variable and state related versus stable and traitlike. Clinically rated formal thought disorder and 5 types of referential disturbance showed substantial stability within participants over time. The sixth type of referential disturbance, the vague reference, was not stable over time. Formal thought disorder was associated with the severity of core psychotic symptoms in patients, whereas referential disturbances showed little or no association with positive or negative symptom severity. Furthermore, changes in psychotic symptoms over time were accompanied by corresponding changes in formal thought disorder but not referential disturbances. These results support the idea that some types of referential disturbances are traitlike and may be reflective of vulnerability as well as manifest illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Linear set-membership state estimation with unknown but bounded disturbances

In this article, we consider the problem of discrete-time linear state estimation when at every discrete instant Δ the Euclidean norm of the discrete-time disturbance ‖w(Δ)‖₂ is bounded within some known value. Specifically, given a hypersphere that contains the uncertain disturbance signal w(Δ) and an ellipsoid containing the uncertain system state x(Δ) at time step Δ, a sub-optimal approach to computing a linear minimax filter which constructs a minimal ellipsoid to contain x(Δ?+?1) is derived. A distinct feature of our approach when compared to earlier solutions is that both the filter and the performance bound can be pre-computed off-line.     

State predictive model following control system for linear time delays

In this paper, we propose a new state predictive model following control system （MFCS）. The considered system has linear time delays. With the MFCS method, we obtain a simple input control law. The bounded property of the internal states for the control is given and the utility of this control design is guaranteed. Finally, an example is given to illustrate the effectiveness of the proposed method.     

Modeling of organism’s adaptive reaction to environmental changes

A multicellular organism is shown to be a community of special self-regulated cells with rigid and flexible regulating links, and a long-term adaptive trend of its system reaction to environmental changes is due to changes in the consumer gradients of groups of cells functioning against the imbalance between synthesis and decay of microstructures. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 136–147, January–February 2008.     

Robust tracking control design for uncertain robotic systems with persistent bounded disturbances

In this study, a robust nonlinear L_∞‐gain tracking control design for uncertain robotic systems is proposed under persistent bounded disturbances. The design objective is that the peak of the tracking error in time domain must be as small as possible under persistent bounded disturbances. Since the nonlinear L_∞ ‐gain optimal tracking control cannot be solved directly, the nonlinear L_∞ ‐gain optimal tracking problem is transformed into a nonlinear L_∞ ‐gain tracking problem by given a prescribed disturbance attenuation level for the L_∞ ‐gain tracking performance. To guarantee that the L_∞ ‐gain tracking performance can be achieved for the uncertain robotic systems, a sliding‐mode scheme is introduced to eliminate the effect of the parameter uncertainties. By virtue of the skew‐symmetric property of the robotic systems, sufficient conditions are developed for solving the robust L_∞ ‐gain tracking control problems in terms of an algebraic equation instead of a differential equation. The proposed method is simple and the algebraic equation can be solved analytically. Therefore, the proposed robust L_∞ ‐gain tracking control scheme is suitable for practical control design of uncertain robotic systems. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society