混沌背景中微弱信号参数估计新方法

本文提出一种基于单向耦合同步的混沌背景中谐波频率估计的新方法。该方法把混沌背景中的谐波频率估计问题转变为同步误差中的谐波频率估计问题,改善了信噪比,在混沌背景中存在强随机噪声情况下,仍能估计出谐波信号频率。仿真实验表明,该方法简单有效,计算量小,且估计效果要优于RBF神经网络方法。     

一种基于XML的非线性编辑初剪辑技术研究

随着计算机信息技术的快速发展,非线性编辑已成为影视业界节目制播主要的工作模式.目前虽然通过数字化大大提升了初剪辑的工作效率,但由于仍采用现有的剪辑工作流程,时间成本消耗偏高.通过分析非线性编辑的需求,将XML架构应用在初剪辑工作中,建立起一套基于XML初剪方式的语法,以提高初剪辑工作效率及节目品质.     

Parameter estimation and stabilization for a wave equation with boundary output harmonic disturbance and non‐collocated control

This paper is concerned with the parameter estimation and stabilization of a one‐dimensional wave equation with harmonic disturbance suffered by boundary observation at one end and the non‐collocated control at the other end. An adaptive observer is designed in terms of measured velocity corrupted by harmonic disturbance with unknown magnitude. The backstepping method for infinite‐dimensional system is adopted in the design of the feedback law. It is shown that the resulting closed‐loop system is asymptotically stable. Meanwhile, the estimated parameter is shown to be convergent to the unknown parameter as time goes to infinity. Copyright © 2010 John Wiley & Sons, Ltd.     

Improving responsiveness of soft aperiodic tasks using proportional slack time

In a real-time system with both hard real-time periodic jobs and soft real-time aperiodic jobs, it is important to guarantee that the deadline of each periodic job is met, as well as to provide a fast response time for each aperiodic job. We propose an algorithm, called Proportional Slack Reserve (PSR), that produces an efficient schedule for such an environment. For every execution unit of a periodic job, the PSR algorithm reserves time which can be used for execution of aperiodic jobs. If reserved time is not available, the algorithm assigns a deadline to an aperiodic job for achieving better responsiveness of aperiodic jobs. The proposed algorithm can fully utilize processing power while meeting all deadlines of periodic jobs. It can also easily reclaim the time unused by the periodic job. We analytically show that for each aperiodic job, the response time in a PSR schedule is no longer than that in a TBS schedule, which is known to be efficient for servicing aperiodic jobs. We also present simulation results in which the response time of PSR is significantly improved over that of TBS, and moreover the performance of PSR compares favorably with TB(N) considering scheduling overhead.     

基于定子电流小波变换的感应电机速度估计算法的研究

提出一种基于齿槽谐波检测的转速估计算法。首先对感应电机定子电流进行小波变换,得到谱后再利用脊线检测算法提取瞬时频率,然后根据齿槽谐波频率估计转速。将该算法在感应电机无速度传感器直接转矩控制系统中进行了仿真,仿真结果表明,使用小波变换的估计算法不受电机参数的影响,明显提高了电机的转速估计精度,并且在整个转速范围内有效,从而也解决的了在低速范围内,转速估计精度低的问题。     

Using a Visual Attention Model to Improve Gaze Tracking Systems in Interactive 3D Applications

This paper introduces the use of a visual attention model to improve the accuracy of gaze tracking systems. Visual attention models simulate the selective attention part of the human visual system. For instance, in a bottom‐up approach, a saliency map is defined for the image and gives an attention weight to every pixel of the image as a function of its colour, edge or intensity. Our algorithm uses an uncertainty window, defined by the gaze tracker accuracy, and located around the gaze point given by the tracker. Then, using a visual attention model, it searches for the most salient points, or objects, located inside this uncertainty window, and determines a novel, and hopefully, better gaze point. This combination of a gaze tracker together with a visual attention model is considered as the main contribution of the paper. We demonstrate the promising results of our method by presenting two experiments conducted in two different contexts: (1) a free exploration of a visually rich 3D virtual environment without a specific task, and (2) a video game based on gaze tracking involving a selection task. Our approach can be used to improve real‐time gaze tracking systems in many interactive 3D applications such as video games or virtual reality applications. The use of a visual attention model can be adapted to any gaze tracker and the visual attention model can also be adapted to the application in which it is used.     

一种基于瞬时无功功率理论的谐波电流实时检测新算法

介绍了传统的基于瞬时无功功率理论的ip-iq谐波电流检测算法;针对谐波检测环节产生的时延问题,提出了一种基于传统的瞬时无功功率理论、通过增加预置补偿角来消除时延的谐波电流实时检测新算法。Matlab动态仿真结果表明,利用增加预置补偿角的新算法进行谐波检测补偿效果较好,补偿后的电流波形接近正弦波,实现了谐波的实时检测,验证了该算法的可行性和有效性。     

一种基于图像块的Legendre矩高精度快速算法

针对图像的Legendre正交矩计算量大和矩值求解过程中存在离散近似误差等问题,提出一种新的高精度快速计算图像Legendre矩方法.文中首先提出一种最大块优先分块策略,然后在此基础上,根据图像像素灰度值的取值特征将图像进行分块表示,以每个图像块为单位计算图像的Legendre矩.实验结果表明,与现有的快速算法相比,文中方法在保证矩值高精确的前提下,有效地减少了算术运算的次数,降低了计算复杂度,具有较快的计算速度.