16 resultados para Time-Delayed Systems

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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遥操作机器人系统的应用和研究是目前机器人学一个重要的研究领域.尤其是网络遥操作系统的产生,更进一步扩大了应用领域,并对控制系统的设计带来了新的挑战.该文主要从控制的角度,面向各种性质的时延(如确定的或未知的,时变的或固定的等)对遥操作系统所带来的稳定性和透明度等问题,针对近年来为解决这些问题所提出的新的控制方法和理论进行系统的综述和分析,指出现有各种方法的优缺点,并提出了今后控制方法的研究方向和应具有的特点.

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提出了一种实时异构系统的集成动态调度算法.该算法通过一个新的任务分配策略以及软实时任务的服务质量QoS(quality of service)降级策略,不仅以统一方式完成了对实时异构系统中硬、软实时任务的集成动态调度,而且提高了算法的调度成功率.同时,还进行了大量的模拟研究.这些模拟以传统的近视算法为基准,将其应用在实时异构系统集成动态调度时的调度成功率与新算法进行比较,模拟结果表明,在多种任务参数取值下,新算法的调度成功率均高于传统的近视算法.

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SAR实时成像系统在国防等很多领域都有着重要的应用 ,系统对数据可视化方面的要求也越来越高 ,但目前国内对SAR实时成像系统的数据可视化方面的研究还不多 提出了一种针对SAR实时成像系统的新的数据可视化方案 ,并已在实际的飞行成像中得到了检验 新方案实时提供的信息更全面、更直观、可分析性更强 ,具有较强的信息表现能力和双向实时交互能力 ,能够较好地辅助对图像的在线分析 还对方案的重要组成部分———缩略图的原理和实现算法做了概括介绍

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实时多处理器系统是解决复杂实时应用的有效手段.然而,目前对实时多处理器调度算法的研究却大多集中在同构系统上,对实时异构系统的调度则研究得比较少.提出了一种新的实时异构系统的动态调度算法.该算法采用了集中式的调度方案,同时,引入了一个新的任务分配策略,从而通过提高任务可行性而提高了算法的调度成功率.此外,为了评估该算法的性能,还进行了大量的模拟研究.由于近视算法经简单修改便可以被应用到实时异构系统的动态调度中,因此,在模拟研究中,以近视算法作为基准,将其应用于实时异构系统动态调度时的性能与新算法进行了比较.模拟结果显示,在多种任务参数的取值下,新算法的调度成功率均高于近视算法.

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实时多处理器系统的动态调度算法一直是实时系统研究中的重要课题,而评价实时调度算法性能的一个最重要的指标是调度成功率.在近视算法的基础上提出了一种新的实时多处理器系统的动态调度算法——节约算法.在该算法中,提出了一个新的处理器选择策略,从而提高了算法的调度成功率.同时,为了研究节约算法的有效性,对其进行了大量的模拟,分析了一些任务参数的变化对算法调度成功率的影响,并与近视算法的调度成功率进行了比较.模拟结果显示,节约算法的调度成功率要优于近视算法.

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分析了实时数据库的事务特征,对以往的研究成果进行了总结,以满足事务的按时完成比率(SuccessRatio)为目标,为实时系统设计了一种使用反馈控制思想的基于优先级的实时数据库缓冲区管理算法FCLRU2 dl,并将该算法与常用的实时数据库事务调度算法和并发控制策略配合进行了测试和评估,证明了算法的优越性。实验中得到的另一个结论是在特定的事务调度算法和并发控制策略下,实时数据库不需要全部位于内存中,可以不是内存数据库。

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We explored the origin of power law distribution observed in single-molecule conformational dynamics experiments. By establishing a kinetic master equation approach to study statistically the microscopic state dynamics, we show that the underlying landscape with exponentially distributed density of states leads to power law distribution of kinetics. The exponential density of states emerges when the system becomes glassy and landscape becomes rough with significant trapping.

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针对一类具有单输入滞后不确定非线性系统 ,采用精确反馈线性化方法和 Lyapunov方法设计出一种使系统终极有界 ( UUB)的无记忆光滑状态反馈鲁棒控制器 .仿真算例表明了本文所采用方法的有效性 .

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The nonlinear behavior varying with the instantaneous response was analyzed through the joint time-frequency analysis method for a class of S. D. O. F nonlinear system. A masking operator an definite regions is defined and two theorems are presented. Based on these, the nonlinear system is modeled with a special time-varying linear one, called the generalized skeleton linear system (GSLS). The frequency skeleton curve and the damping skeleton curve are defined to describe the main feature of the non-linearity as well. Moreover, an identification method is proposed through the skeleton curves and the time-frequency filtering technique.

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In the previous paper, a class of nonlinear system is mapped to a so-called skeleton linear model (SLM) based on the joint time-frequency analysis method. Behavior of the nonlinear system may be indicated quantitatively by the variance of the coefficients of SLM versus its response. Using this model we propose an identification method for nonlinear systems based on nonstationary vibration data in this paper. The key technique in the identification procedure is a time-frequency filtering method by which solution of the SLM is extracted from the response data of the corresponding nonlinear system. Two time-frequency filtering methods are discussed here. One is based on the quadratic time-frequency distribution and its inverse transform, the other is based on the quadratic time-frequency distribution and the wavelet transform. Both numerical examples and an experimental application are given to illustrate the validity of the technique.

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The joint time-frequency analysis method is adopted to study the nonlinear behavior varying with the instantaneous response for a class of S.D.O.F nonlinear system. A time-frequency masking operator, together with the conception of effective time-frequency region of the asymptotic signal are defined here. Based on these mathematical foundations, a so-called skeleton linear model (SLM) is constructed which has similar nonlinear characteristics with the nonlinear system. Two skeleton curves are deduced which can indicate the stiffness and damping in the nonlinear system. The relationship between the SLM and the nonlinear system, both parameters and solutions, is clarified. Based on this work a new identification technique of nonlinear systems using the nonstationary vibration data will be proposed through time-frequency filtering technique and wavelet transform in the following paper.